Merge branch 'for-usb-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sarah...
[pandora-kernel.git] / fs / ext4 / inode.c
1 /*
2  *  linux/fs/ext4/inode.c
3  *
4  * Copyright (C) 1992, 1993, 1994, 1995
5  * Remy Card (card@masi.ibp.fr)
6  * Laboratoire MASI - Institut Blaise Pascal
7  * Universite Pierre et Marie Curie (Paris VI)
8  *
9  *  from
10  *
11  *  linux/fs/minix/inode.c
12  *
13  *  Copyright (C) 1991, 1992  Linus Torvalds
14  *
15  *  Goal-directed block allocation by Stephen Tweedie
16  *      (sct@redhat.com), 1993, 1998
17  *  Big-endian to little-endian byte-swapping/bitmaps by
18  *        David S. Miller (davem@caip.rutgers.edu), 1995
19  *  64-bit file support on 64-bit platforms by Jakub Jelinek
20  *      (jj@sunsite.ms.mff.cuni.cz)
21  *
22  *  Assorted race fixes, rewrite of ext4_get_block() by Al Viro, 2000
23  */
24
25 #include <linux/module.h>
26 #include <linux/fs.h>
27 #include <linux/time.h>
28 #include <linux/jbd2.h>
29 #include <linux/highuid.h>
30 #include <linux/pagemap.h>
31 #include <linux/quotaops.h>
32 #include <linux/string.h>
33 #include <linux/buffer_head.h>
34 #include <linux/writeback.h>
35 #include <linux/pagevec.h>
36 #include <linux/mpage.h>
37 #include <linux/namei.h>
38 #include <linux/uio.h>
39 #include <linux/bio.h>
40 #include <linux/workqueue.h>
41 #include <linux/kernel.h>
42 #include <linux/slab.h>
43
44 #include "ext4_jbd2.h"
45 #include "xattr.h"
46 #include "acl.h"
47 #include "ext4_extents.h"
48
49 #include <trace/events/ext4.h>
50
51 #define MPAGE_DA_EXTENT_TAIL 0x01
52
53 static inline int ext4_begin_ordered_truncate(struct inode *inode,
54                                               loff_t new_size)
55 {
56         trace_ext4_begin_ordered_truncate(inode, new_size);
57         return jbd2_journal_begin_ordered_truncate(
58                                         EXT4_SB(inode->i_sb)->s_journal,
59                                         &EXT4_I(inode)->jinode,
60                                         new_size);
61 }
62
63 static void ext4_invalidatepage(struct page *page, unsigned long offset);
64 static int noalloc_get_block_write(struct inode *inode, sector_t iblock,
65                                    struct buffer_head *bh_result, int create);
66 static int ext4_set_bh_endio(struct buffer_head *bh, struct inode *inode);
67 static void ext4_end_io_buffer_write(struct buffer_head *bh, int uptodate);
68 static int __ext4_journalled_writepage(struct page *page, unsigned int len);
69 static int ext4_bh_delay_or_unwritten(handle_t *handle, struct buffer_head *bh);
70
71 /*
72  * Test whether an inode is a fast symlink.
73  */
74 static int ext4_inode_is_fast_symlink(struct inode *inode)
75 {
76         int ea_blocks = EXT4_I(inode)->i_file_acl ?
77                 (inode->i_sb->s_blocksize >> 9) : 0;
78
79         return (S_ISLNK(inode->i_mode) && inode->i_blocks - ea_blocks == 0);
80 }
81
82 /*
83  * Work out how many blocks we need to proceed with the next chunk of a
84  * truncate transaction.
85  */
86 static unsigned long blocks_for_truncate(struct inode *inode)
87 {
88         ext4_lblk_t needed;
89
90         needed = inode->i_blocks >> (inode->i_sb->s_blocksize_bits - 9);
91
92         /* Give ourselves just enough room to cope with inodes in which
93          * i_blocks is corrupt: we've seen disk corruptions in the past
94          * which resulted in random data in an inode which looked enough
95          * like a regular file for ext4 to try to delete it.  Things
96          * will go a bit crazy if that happens, but at least we should
97          * try not to panic the whole kernel. */
98         if (needed < 2)
99                 needed = 2;
100
101         /* But we need to bound the transaction so we don't overflow the
102          * journal. */
103         if (needed > EXT4_MAX_TRANS_DATA)
104                 needed = EXT4_MAX_TRANS_DATA;
105
106         return EXT4_DATA_TRANS_BLOCKS(inode->i_sb) + needed;
107 }
108
109 /*
110  * Truncate transactions can be complex and absolutely huge.  So we need to
111  * be able to restart the transaction at a conventient checkpoint to make
112  * sure we don't overflow the journal.
113  *
114  * start_transaction gets us a new handle for a truncate transaction,
115  * and extend_transaction tries to extend the existing one a bit.  If
116  * extend fails, we need to propagate the failure up and restart the
117  * transaction in the top-level truncate loop. --sct
118  */
119 static handle_t *start_transaction(struct inode *inode)
120 {
121         handle_t *result;
122
123         result = ext4_journal_start(inode, blocks_for_truncate(inode));
124         if (!IS_ERR(result))
125                 return result;
126
127         ext4_std_error(inode->i_sb, PTR_ERR(result));
128         return result;
129 }
130
131 /*
132  * Try to extend this transaction for the purposes of truncation.
133  *
134  * Returns 0 if we managed to create more room.  If we can't create more
135  * room, and the transaction must be restarted we return 1.
136  */
137 static int try_to_extend_transaction(handle_t *handle, struct inode *inode)
138 {
139         if (!ext4_handle_valid(handle))
140                 return 0;
141         if (ext4_handle_has_enough_credits(handle, EXT4_RESERVE_TRANS_BLOCKS+1))
142                 return 0;
143         if (!ext4_journal_extend(handle, blocks_for_truncate(inode)))
144                 return 0;
145         return 1;
146 }
147
148 /*
149  * Restart the transaction associated with *handle.  This does a commit,
150  * so before we call here everything must be consistently dirtied against
151  * this transaction.
152  */
153 int ext4_truncate_restart_trans(handle_t *handle, struct inode *inode,
154                                  int nblocks)
155 {
156         int ret;
157
158         /*
159          * Drop i_data_sem to avoid deadlock with ext4_map_blocks.  At this
160          * moment, get_block can be called only for blocks inside i_size since
161          * page cache has been already dropped and writes are blocked by
162          * i_mutex. So we can safely drop the i_data_sem here.
163          */
164         BUG_ON(EXT4_JOURNAL(inode) == NULL);
165         jbd_debug(2, "restarting handle %p\n", handle);
166         up_write(&EXT4_I(inode)->i_data_sem);
167         ret = ext4_journal_restart(handle, blocks_for_truncate(inode));
168         down_write(&EXT4_I(inode)->i_data_sem);
169         ext4_discard_preallocations(inode);
170
171         return ret;
172 }
173
174 /*
175  * Called at the last iput() if i_nlink is zero.
176  */
177 void ext4_evict_inode(struct inode *inode)
178 {
179         handle_t *handle;
180         int err;
181
182         trace_ext4_evict_inode(inode);
183         if (inode->i_nlink) {
184                 truncate_inode_pages(&inode->i_data, 0);
185                 goto no_delete;
186         }
187
188         if (!is_bad_inode(inode))
189                 dquot_initialize(inode);
190
191         if (ext4_should_order_data(inode))
192                 ext4_begin_ordered_truncate(inode, 0);
193         truncate_inode_pages(&inode->i_data, 0);
194
195         if (is_bad_inode(inode))
196                 goto no_delete;
197
198         handle = ext4_journal_start(inode, blocks_for_truncate(inode)+3);
199         if (IS_ERR(handle)) {
200                 ext4_std_error(inode->i_sb, PTR_ERR(handle));
201                 /*
202                  * If we're going to skip the normal cleanup, we still need to
203                  * make sure that the in-core orphan linked list is properly
204                  * cleaned up.
205                  */
206                 ext4_orphan_del(NULL, inode);
207                 goto no_delete;
208         }
209
210         if (IS_SYNC(inode))
211                 ext4_handle_sync(handle);
212         inode->i_size = 0;
213         err = ext4_mark_inode_dirty(handle, inode);
214         if (err) {
215                 ext4_warning(inode->i_sb,
216                              "couldn't mark inode dirty (err %d)", err);
217                 goto stop_handle;
218         }
219         if (inode->i_blocks)
220                 ext4_truncate(inode);
221
222         /*
223          * ext4_ext_truncate() doesn't reserve any slop when it
224          * restarts journal transactions; therefore there may not be
225          * enough credits left in the handle to remove the inode from
226          * the orphan list and set the dtime field.
227          */
228         if (!ext4_handle_has_enough_credits(handle, 3)) {
229                 err = ext4_journal_extend(handle, 3);
230                 if (err > 0)
231                         err = ext4_journal_restart(handle, 3);
232                 if (err != 0) {
233                         ext4_warning(inode->i_sb,
234                                      "couldn't extend journal (err %d)", err);
235                 stop_handle:
236                         ext4_journal_stop(handle);
237                         ext4_orphan_del(NULL, inode);
238                         goto no_delete;
239                 }
240         }
241
242         /*
243          * Kill off the orphan record which ext4_truncate created.
244          * AKPM: I think this can be inside the above `if'.
245          * Note that ext4_orphan_del() has to be able to cope with the
246          * deletion of a non-existent orphan - this is because we don't
247          * know if ext4_truncate() actually created an orphan record.
248          * (Well, we could do this if we need to, but heck - it works)
249          */
250         ext4_orphan_del(handle, inode);
251         EXT4_I(inode)->i_dtime  = get_seconds();
252
253         /*
254          * One subtle ordering requirement: if anything has gone wrong
255          * (transaction abort, IO errors, whatever), then we can still
256          * do these next steps (the fs will already have been marked as
257          * having errors), but we can't free the inode if the mark_dirty
258          * fails.
259          */
260         if (ext4_mark_inode_dirty(handle, inode))
261                 /* If that failed, just do the required in-core inode clear. */
262                 ext4_clear_inode(inode);
263         else
264                 ext4_free_inode(handle, inode);
265         ext4_journal_stop(handle);
266         return;
267 no_delete:
268         ext4_clear_inode(inode);        /* We must guarantee clearing of inode... */
269 }
270
271 typedef struct {
272         __le32  *p;
273         __le32  key;
274         struct buffer_head *bh;
275 } Indirect;
276
277 static inline void add_chain(Indirect *p, struct buffer_head *bh, __le32 *v)
278 {
279         p->key = *(p->p = v);
280         p->bh = bh;
281 }
282
283 /**
284  *      ext4_block_to_path - parse the block number into array of offsets
285  *      @inode: inode in question (we are only interested in its superblock)
286  *      @i_block: block number to be parsed
287  *      @offsets: array to store the offsets in
288  *      @boundary: set this non-zero if the referred-to block is likely to be
289  *             followed (on disk) by an indirect block.
290  *
291  *      To store the locations of file's data ext4 uses a data structure common
292  *      for UNIX filesystems - tree of pointers anchored in the inode, with
293  *      data blocks at leaves and indirect blocks in intermediate nodes.
294  *      This function translates the block number into path in that tree -
295  *      return value is the path length and @offsets[n] is the offset of
296  *      pointer to (n+1)th node in the nth one. If @block is out of range
297  *      (negative or too large) warning is printed and zero returned.
298  *
299  *      Note: function doesn't find node addresses, so no IO is needed. All
300  *      we need to know is the capacity of indirect blocks (taken from the
301  *      inode->i_sb).
302  */
303
304 /*
305  * Portability note: the last comparison (check that we fit into triple
306  * indirect block) is spelled differently, because otherwise on an
307  * architecture with 32-bit longs and 8Kb pages we might get into trouble
308  * if our filesystem had 8Kb blocks. We might use long long, but that would
309  * kill us on x86. Oh, well, at least the sign propagation does not matter -
310  * i_block would have to be negative in the very beginning, so we would not
311  * get there at all.
312  */
313
314 static int ext4_block_to_path(struct inode *inode,
315                               ext4_lblk_t i_block,
316                               ext4_lblk_t offsets[4], int *boundary)
317 {
318         int ptrs = EXT4_ADDR_PER_BLOCK(inode->i_sb);
319         int ptrs_bits = EXT4_ADDR_PER_BLOCK_BITS(inode->i_sb);
320         const long direct_blocks = EXT4_NDIR_BLOCKS,
321                 indirect_blocks = ptrs,
322                 double_blocks = (1 << (ptrs_bits * 2));
323         int n = 0;
324         int final = 0;
325
326         if (i_block < direct_blocks) {
327                 offsets[n++] = i_block;
328                 final = direct_blocks;
329         } else if ((i_block -= direct_blocks) < indirect_blocks) {
330                 offsets[n++] = EXT4_IND_BLOCK;
331                 offsets[n++] = i_block;
332                 final = ptrs;
333         } else if ((i_block -= indirect_blocks) < double_blocks) {
334                 offsets[n++] = EXT4_DIND_BLOCK;
335                 offsets[n++] = i_block >> ptrs_bits;
336                 offsets[n++] = i_block & (ptrs - 1);
337                 final = ptrs;
338         } else if (((i_block -= double_blocks) >> (ptrs_bits * 2)) < ptrs) {
339                 offsets[n++] = EXT4_TIND_BLOCK;
340                 offsets[n++] = i_block >> (ptrs_bits * 2);
341                 offsets[n++] = (i_block >> ptrs_bits) & (ptrs - 1);
342                 offsets[n++] = i_block & (ptrs - 1);
343                 final = ptrs;
344         } else {
345                 ext4_warning(inode->i_sb, "block %lu > max in inode %lu",
346                              i_block + direct_blocks +
347                              indirect_blocks + double_blocks, inode->i_ino);
348         }
349         if (boundary)
350                 *boundary = final - 1 - (i_block & (ptrs - 1));
351         return n;
352 }
353
354 static int __ext4_check_blockref(const char *function, unsigned int line,
355                                  struct inode *inode,
356                                  __le32 *p, unsigned int max)
357 {
358         struct ext4_super_block *es = EXT4_SB(inode->i_sb)->s_es;
359         __le32 *bref = p;
360         unsigned int blk;
361
362         while (bref < p+max) {
363                 blk = le32_to_cpu(*bref++);
364                 if (blk &&
365                     unlikely(!ext4_data_block_valid(EXT4_SB(inode->i_sb),
366                                                     blk, 1))) {
367                         es->s_last_error_block = cpu_to_le64(blk);
368                         ext4_error_inode(inode, function, line, blk,
369                                          "invalid block");
370                         return -EIO;
371                 }
372         }
373         return 0;
374 }
375
376
377 #define ext4_check_indirect_blockref(inode, bh)                         \
378         __ext4_check_blockref(__func__, __LINE__, inode,                \
379                               (__le32 *)(bh)->b_data,                   \
380                               EXT4_ADDR_PER_BLOCK((inode)->i_sb))
381
382 #define ext4_check_inode_blockref(inode)                                \
383         __ext4_check_blockref(__func__, __LINE__, inode,                \
384                               EXT4_I(inode)->i_data,                    \
385                               EXT4_NDIR_BLOCKS)
386
387 /**
388  *      ext4_get_branch - read the chain of indirect blocks leading to data
389  *      @inode: inode in question
390  *      @depth: depth of the chain (1 - direct pointer, etc.)
391  *      @offsets: offsets of pointers in inode/indirect blocks
392  *      @chain: place to store the result
393  *      @err: here we store the error value
394  *
395  *      Function fills the array of triples <key, p, bh> and returns %NULL
396  *      if everything went OK or the pointer to the last filled triple
397  *      (incomplete one) otherwise. Upon the return chain[i].key contains
398  *      the number of (i+1)-th block in the chain (as it is stored in memory,
399  *      i.e. little-endian 32-bit), chain[i].p contains the address of that
400  *      number (it points into struct inode for i==0 and into the bh->b_data
401  *      for i>0) and chain[i].bh points to the buffer_head of i-th indirect
402  *      block for i>0 and NULL for i==0. In other words, it holds the block
403  *      numbers of the chain, addresses they were taken from (and where we can
404  *      verify that chain did not change) and buffer_heads hosting these
405  *      numbers.
406  *
407  *      Function stops when it stumbles upon zero pointer (absent block)
408  *              (pointer to last triple returned, *@err == 0)
409  *      or when it gets an IO error reading an indirect block
410  *              (ditto, *@err == -EIO)
411  *      or when it reads all @depth-1 indirect blocks successfully and finds
412  *      the whole chain, all way to the data (returns %NULL, *err == 0).
413  *
414  *      Need to be called with
415  *      down_read(&EXT4_I(inode)->i_data_sem)
416  */
417 static Indirect *ext4_get_branch(struct inode *inode, int depth,
418                                  ext4_lblk_t  *offsets,
419                                  Indirect chain[4], int *err)
420 {
421         struct super_block *sb = inode->i_sb;
422         Indirect *p = chain;
423         struct buffer_head *bh;
424
425         *err = 0;
426         /* i_data is not going away, no lock needed */
427         add_chain(chain, NULL, EXT4_I(inode)->i_data + *offsets);
428         if (!p->key)
429                 goto no_block;
430         while (--depth) {
431                 bh = sb_getblk(sb, le32_to_cpu(p->key));
432                 if (unlikely(!bh))
433                         goto failure;
434
435                 if (!bh_uptodate_or_lock(bh)) {
436                         if (bh_submit_read(bh) < 0) {
437                                 put_bh(bh);
438                                 goto failure;
439                         }
440                         /* validate block references */
441                         if (ext4_check_indirect_blockref(inode, bh)) {
442                                 put_bh(bh);
443                                 goto failure;
444                         }
445                 }
446
447                 add_chain(++p, bh, (__le32 *)bh->b_data + *++offsets);
448                 /* Reader: end */
449                 if (!p->key)
450                         goto no_block;
451         }
452         return NULL;
453
454 failure:
455         *err = -EIO;
456 no_block:
457         return p;
458 }
459
460 /**
461  *      ext4_find_near - find a place for allocation with sufficient locality
462  *      @inode: owner
463  *      @ind: descriptor of indirect block.
464  *
465  *      This function returns the preferred place for block allocation.
466  *      It is used when heuristic for sequential allocation fails.
467  *      Rules are:
468  *        + if there is a block to the left of our position - allocate near it.
469  *        + if pointer will live in indirect block - allocate near that block.
470  *        + if pointer will live in inode - allocate in the same
471  *          cylinder group.
472  *
473  * In the latter case we colour the starting block by the callers PID to
474  * prevent it from clashing with concurrent allocations for a different inode
475  * in the same block group.   The PID is used here so that functionally related
476  * files will be close-by on-disk.
477  *
478  *      Caller must make sure that @ind is valid and will stay that way.
479  */
480 static ext4_fsblk_t ext4_find_near(struct inode *inode, Indirect *ind)
481 {
482         struct ext4_inode_info *ei = EXT4_I(inode);
483         __le32 *start = ind->bh ? (__le32 *) ind->bh->b_data : ei->i_data;
484         __le32 *p;
485         ext4_fsblk_t bg_start;
486         ext4_fsblk_t last_block;
487         ext4_grpblk_t colour;
488         ext4_group_t block_group;
489         int flex_size = ext4_flex_bg_size(EXT4_SB(inode->i_sb));
490
491         /* Try to find previous block */
492         for (p = ind->p - 1; p >= start; p--) {
493                 if (*p)
494                         return le32_to_cpu(*p);
495         }
496
497         /* No such thing, so let's try location of indirect block */
498         if (ind->bh)
499                 return ind->bh->b_blocknr;
500
501         /*
502          * It is going to be referred to from the inode itself? OK, just put it
503          * into the same cylinder group then.
504          */
505         block_group = ei->i_block_group;
506         if (flex_size >= EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME) {
507                 block_group &= ~(flex_size-1);
508                 if (S_ISREG(inode->i_mode))
509                         block_group++;
510         }
511         bg_start = ext4_group_first_block_no(inode->i_sb, block_group);
512         last_block = ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es) - 1;
513
514         /*
515          * If we are doing delayed allocation, we don't need take
516          * colour into account.
517          */
518         if (test_opt(inode->i_sb, DELALLOC))
519                 return bg_start;
520
521         if (bg_start + EXT4_BLOCKS_PER_GROUP(inode->i_sb) <= last_block)
522                 colour = (current->pid % 16) *
523                         (EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16);
524         else
525                 colour = (current->pid % 16) * ((last_block - bg_start) / 16);
526         return bg_start + colour;
527 }
528
529 /**
530  *      ext4_find_goal - find a preferred place for allocation.
531  *      @inode: owner
532  *      @block:  block we want
533  *      @partial: pointer to the last triple within a chain
534  *
535  *      Normally this function find the preferred place for block allocation,
536  *      returns it.
537  *      Because this is only used for non-extent files, we limit the block nr
538  *      to 32 bits.
539  */
540 static ext4_fsblk_t ext4_find_goal(struct inode *inode, ext4_lblk_t block,
541                                    Indirect *partial)
542 {
543         ext4_fsblk_t goal;
544
545         /*
546          * XXX need to get goal block from mballoc's data structures
547          */
548
549         goal = ext4_find_near(inode, partial);
550         goal = goal & EXT4_MAX_BLOCK_FILE_PHYS;
551         return goal;
552 }
553
554 /**
555  *      ext4_blks_to_allocate: Look up the block map and count the number
556  *      of direct blocks need to be allocated for the given branch.
557  *
558  *      @branch: chain of indirect blocks
559  *      @k: number of blocks need for indirect blocks
560  *      @blks: number of data blocks to be mapped.
561  *      @blocks_to_boundary:  the offset in the indirect block
562  *
563  *      return the total number of blocks to be allocate, including the
564  *      direct and indirect blocks.
565  */
566 static int ext4_blks_to_allocate(Indirect *branch, int k, unsigned int blks,
567                                  int blocks_to_boundary)
568 {
569         unsigned int count = 0;
570
571         /*
572          * Simple case, [t,d]Indirect block(s) has not allocated yet
573          * then it's clear blocks on that path have not allocated
574          */
575         if (k > 0) {
576                 /* right now we don't handle cross boundary allocation */
577                 if (blks < blocks_to_boundary + 1)
578                         count += blks;
579                 else
580                         count += blocks_to_boundary + 1;
581                 return count;
582         }
583
584         count++;
585         while (count < blks && count <= blocks_to_boundary &&
586                 le32_to_cpu(*(branch[0].p + count)) == 0) {
587                 count++;
588         }
589         return count;
590 }
591
592 /**
593  *      ext4_alloc_blocks: multiple allocate blocks needed for a branch
594  *      @indirect_blks: the number of blocks need to allocate for indirect
595  *                      blocks
596  *
597  *      @new_blocks: on return it will store the new block numbers for
598  *      the indirect blocks(if needed) and the first direct block,
599  *      @blks:  on return it will store the total number of allocated
600  *              direct blocks
601  */
602 static int ext4_alloc_blocks(handle_t *handle, struct inode *inode,
603                              ext4_lblk_t iblock, ext4_fsblk_t goal,
604                              int indirect_blks, int blks,
605                              ext4_fsblk_t new_blocks[4], int *err)
606 {
607         struct ext4_allocation_request ar;
608         int target, i;
609         unsigned long count = 0, blk_allocated = 0;
610         int index = 0;
611         ext4_fsblk_t current_block = 0;
612         int ret = 0;
613
614         /*
615          * Here we try to allocate the requested multiple blocks at once,
616          * on a best-effort basis.
617          * To build a branch, we should allocate blocks for
618          * the indirect blocks(if not allocated yet), and at least
619          * the first direct block of this branch.  That's the
620          * minimum number of blocks need to allocate(required)
621          */
622         /* first we try to allocate the indirect blocks */
623         target = indirect_blks;
624         while (target > 0) {
625                 count = target;
626                 /* allocating blocks for indirect blocks and direct blocks */
627                 current_block = ext4_new_meta_blocks(handle, inode,
628                                                         goal, &count, err);
629                 if (*err)
630                         goto failed_out;
631
632                 if (unlikely(current_block + count > EXT4_MAX_BLOCK_FILE_PHYS)) {
633                         EXT4_ERROR_INODE(inode,
634                                          "current_block %llu + count %lu > %d!",
635                                          current_block, count,
636                                          EXT4_MAX_BLOCK_FILE_PHYS);
637                         *err = -EIO;
638                         goto failed_out;
639                 }
640
641                 target -= count;
642                 /* allocate blocks for indirect blocks */
643                 while (index < indirect_blks && count) {
644                         new_blocks[index++] = current_block++;
645                         count--;
646                 }
647                 if (count > 0) {
648                         /*
649                          * save the new block number
650                          * for the first direct block
651                          */
652                         new_blocks[index] = current_block;
653                         printk(KERN_INFO "%s returned more blocks than "
654                                                 "requested\n", __func__);
655                         WARN_ON(1);
656                         break;
657                 }
658         }
659
660         target = blks - count ;
661         blk_allocated = count;
662         if (!target)
663                 goto allocated;
664         /* Now allocate data blocks */
665         memset(&ar, 0, sizeof(ar));
666         ar.inode = inode;
667         ar.goal = goal;
668         ar.len = target;
669         ar.logical = iblock;
670         if (S_ISREG(inode->i_mode))
671                 /* enable in-core preallocation only for regular files */
672                 ar.flags = EXT4_MB_HINT_DATA;
673
674         current_block = ext4_mb_new_blocks(handle, &ar, err);
675         if (unlikely(current_block + ar.len > EXT4_MAX_BLOCK_FILE_PHYS)) {
676                 EXT4_ERROR_INODE(inode,
677                                  "current_block %llu + ar.len %d > %d!",
678                                  current_block, ar.len,
679                                  EXT4_MAX_BLOCK_FILE_PHYS);
680                 *err = -EIO;
681                 goto failed_out;
682         }
683
684         if (*err && (target == blks)) {
685                 /*
686                  * if the allocation failed and we didn't allocate
687                  * any blocks before
688                  */
689                 goto failed_out;
690         }
691         if (!*err) {
692                 if (target == blks) {
693                         /*
694                          * save the new block number
695                          * for the first direct block
696                          */
697                         new_blocks[index] = current_block;
698                 }
699                 blk_allocated += ar.len;
700         }
701 allocated:
702         /* total number of blocks allocated for direct blocks */
703         ret = blk_allocated;
704         *err = 0;
705         return ret;
706 failed_out:
707         for (i = 0; i < index; i++)
708                 ext4_free_blocks(handle, inode, 0, new_blocks[i], 1, 0);
709         return ret;
710 }
711
712 /**
713  *      ext4_alloc_branch - allocate and set up a chain of blocks.
714  *      @inode: owner
715  *      @indirect_blks: number of allocated indirect blocks
716  *      @blks: number of allocated direct blocks
717  *      @offsets: offsets (in the blocks) to store the pointers to next.
718  *      @branch: place to store the chain in.
719  *
720  *      This function allocates blocks, zeroes out all but the last one,
721  *      links them into chain and (if we are synchronous) writes them to disk.
722  *      In other words, it prepares a branch that can be spliced onto the
723  *      inode. It stores the information about that chain in the branch[], in
724  *      the same format as ext4_get_branch() would do. We are calling it after
725  *      we had read the existing part of chain and partial points to the last
726  *      triple of that (one with zero ->key). Upon the exit we have the same
727  *      picture as after the successful ext4_get_block(), except that in one
728  *      place chain is disconnected - *branch->p is still zero (we did not
729  *      set the last link), but branch->key contains the number that should
730  *      be placed into *branch->p to fill that gap.
731  *
732  *      If allocation fails we free all blocks we've allocated (and forget
733  *      their buffer_heads) and return the error value the from failed
734  *      ext4_alloc_block() (normally -ENOSPC). Otherwise we set the chain
735  *      as described above and return 0.
736  */
737 static int ext4_alloc_branch(handle_t *handle, struct inode *inode,
738                              ext4_lblk_t iblock, int indirect_blks,
739                              int *blks, ext4_fsblk_t goal,
740                              ext4_lblk_t *offsets, Indirect *branch)
741 {
742         int blocksize = inode->i_sb->s_blocksize;
743         int i, n = 0;
744         int err = 0;
745         struct buffer_head *bh;
746         int num;
747         ext4_fsblk_t new_blocks[4];
748         ext4_fsblk_t current_block;
749
750         num = ext4_alloc_blocks(handle, inode, iblock, goal, indirect_blks,
751                                 *blks, new_blocks, &err);
752         if (err)
753                 return err;
754
755         branch[0].key = cpu_to_le32(new_blocks[0]);
756         /*
757          * metadata blocks and data blocks are allocated.
758          */
759         for (n = 1; n <= indirect_blks;  n++) {
760                 /*
761                  * Get buffer_head for parent block, zero it out
762                  * and set the pointer to new one, then send
763                  * parent to disk.
764                  */
765                 bh = sb_getblk(inode->i_sb, new_blocks[n-1]);
766                 if (unlikely(!bh)) {
767                         err = -EIO;
768                         goto failed;
769                 }
770
771                 branch[n].bh = bh;
772                 lock_buffer(bh);
773                 BUFFER_TRACE(bh, "call get_create_access");
774                 err = ext4_journal_get_create_access(handle, bh);
775                 if (err) {
776                         /* Don't brelse(bh) here; it's done in
777                          * ext4_journal_forget() below */
778                         unlock_buffer(bh);
779                         goto failed;
780                 }
781
782                 memset(bh->b_data, 0, blocksize);
783                 branch[n].p = (__le32 *) bh->b_data + offsets[n];
784                 branch[n].key = cpu_to_le32(new_blocks[n]);
785                 *branch[n].p = branch[n].key;
786                 if (n == indirect_blks) {
787                         current_block = new_blocks[n];
788                         /*
789                          * End of chain, update the last new metablock of
790                          * the chain to point to the new allocated
791                          * data blocks numbers
792                          */
793                         for (i = 1; i < num; i++)
794                                 *(branch[n].p + i) = cpu_to_le32(++current_block);
795                 }
796                 BUFFER_TRACE(bh, "marking uptodate");
797                 set_buffer_uptodate(bh);
798                 unlock_buffer(bh);
799
800                 BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
801                 err = ext4_handle_dirty_metadata(handle, inode, bh);
802                 if (err)
803                         goto failed;
804         }
805         *blks = num;
806         return err;
807 failed:
808         /* Allocation failed, free what we already allocated */
809         ext4_free_blocks(handle, inode, 0, new_blocks[0], 1, 0);
810         for (i = 1; i <= n ; i++) {
811                 /*
812                  * branch[i].bh is newly allocated, so there is no
813                  * need to revoke the block, which is why we don't
814                  * need to set EXT4_FREE_BLOCKS_METADATA.
815                  */
816                 ext4_free_blocks(handle, inode, 0, new_blocks[i], 1,
817                                  EXT4_FREE_BLOCKS_FORGET);
818         }
819         for (i = n+1; i < indirect_blks; i++)
820                 ext4_free_blocks(handle, inode, 0, new_blocks[i], 1, 0);
821
822         ext4_free_blocks(handle, inode, 0, new_blocks[i], num, 0);
823
824         return err;
825 }
826
827 /**
828  * ext4_splice_branch - splice the allocated branch onto inode.
829  * @inode: owner
830  * @block: (logical) number of block we are adding
831  * @chain: chain of indirect blocks (with a missing link - see
832  *      ext4_alloc_branch)
833  * @where: location of missing link
834  * @num:   number of indirect blocks we are adding
835  * @blks:  number of direct blocks we are adding
836  *
837  * This function fills the missing link and does all housekeeping needed in
838  * inode (->i_blocks, etc.). In case of success we end up with the full
839  * chain to new block and return 0.
840  */
841 static int ext4_splice_branch(handle_t *handle, struct inode *inode,
842                               ext4_lblk_t block, Indirect *where, int num,
843                               int blks)
844 {
845         int i;
846         int err = 0;
847         ext4_fsblk_t current_block;
848
849         /*
850          * If we're splicing into a [td]indirect block (as opposed to the
851          * inode) then we need to get write access to the [td]indirect block
852          * before the splice.
853          */
854         if (where->bh) {
855                 BUFFER_TRACE(where->bh, "get_write_access");
856                 err = ext4_journal_get_write_access(handle, where->bh);
857                 if (err)
858                         goto err_out;
859         }
860         /* That's it */
861
862         *where->p = where->key;
863
864         /*
865          * Update the host buffer_head or inode to point to more just allocated
866          * direct blocks blocks
867          */
868         if (num == 0 && blks > 1) {
869                 current_block = le32_to_cpu(where->key) + 1;
870                 for (i = 1; i < blks; i++)
871                         *(where->p + i) = cpu_to_le32(current_block++);
872         }
873
874         /* We are done with atomic stuff, now do the rest of housekeeping */
875         /* had we spliced it onto indirect block? */
876         if (where->bh) {
877                 /*
878                  * If we spliced it onto an indirect block, we haven't
879                  * altered the inode.  Note however that if it is being spliced
880                  * onto an indirect block at the very end of the file (the
881                  * file is growing) then we *will* alter the inode to reflect
882                  * the new i_size.  But that is not done here - it is done in
883                  * generic_commit_write->__mark_inode_dirty->ext4_dirty_inode.
884                  */
885                 jbd_debug(5, "splicing indirect only\n");
886                 BUFFER_TRACE(where->bh, "call ext4_handle_dirty_metadata");
887                 err = ext4_handle_dirty_metadata(handle, inode, where->bh);
888                 if (err)
889                         goto err_out;
890         } else {
891                 /*
892                  * OK, we spliced it into the inode itself on a direct block.
893                  */
894                 ext4_mark_inode_dirty(handle, inode);
895                 jbd_debug(5, "splicing direct\n");
896         }
897         return err;
898
899 err_out:
900         for (i = 1; i <= num; i++) {
901                 /*
902                  * branch[i].bh is newly allocated, so there is no
903                  * need to revoke the block, which is why we don't
904                  * need to set EXT4_FREE_BLOCKS_METADATA.
905                  */
906                 ext4_free_blocks(handle, inode, where[i].bh, 0, 1,
907                                  EXT4_FREE_BLOCKS_FORGET);
908         }
909         ext4_free_blocks(handle, inode, 0, le32_to_cpu(where[num].key),
910                          blks, 0);
911
912         return err;
913 }
914
915 /*
916  * The ext4_ind_map_blocks() function handles non-extents inodes
917  * (i.e., using the traditional indirect/double-indirect i_blocks
918  * scheme) for ext4_map_blocks().
919  *
920  * Allocation strategy is simple: if we have to allocate something, we will
921  * have to go the whole way to leaf. So let's do it before attaching anything
922  * to tree, set linkage between the newborn blocks, write them if sync is
923  * required, recheck the path, free and repeat if check fails, otherwise
924  * set the last missing link (that will protect us from any truncate-generated
925  * removals - all blocks on the path are immune now) and possibly force the
926  * write on the parent block.
927  * That has a nice additional property: no special recovery from the failed
928  * allocations is needed - we simply release blocks and do not touch anything
929  * reachable from inode.
930  *
931  * `handle' can be NULL if create == 0.
932  *
933  * return > 0, # of blocks mapped or allocated.
934  * return = 0, if plain lookup failed.
935  * return < 0, error case.
936  *
937  * The ext4_ind_get_blocks() function should be called with
938  * down_write(&EXT4_I(inode)->i_data_sem) if allocating filesystem
939  * blocks (i.e., flags has EXT4_GET_BLOCKS_CREATE set) or
940  * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system
941  * blocks.
942  */
943 static int ext4_ind_map_blocks(handle_t *handle, struct inode *inode,
944                                struct ext4_map_blocks *map,
945                                int flags)
946 {
947         int err = -EIO;
948         ext4_lblk_t offsets[4];
949         Indirect chain[4];
950         Indirect *partial;
951         ext4_fsblk_t goal;
952         int indirect_blks;
953         int blocks_to_boundary = 0;
954         int depth;
955         int count = 0;
956         ext4_fsblk_t first_block = 0;
957
958         J_ASSERT(!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)));
959         J_ASSERT(handle != NULL || (flags & EXT4_GET_BLOCKS_CREATE) == 0);
960         depth = ext4_block_to_path(inode, map->m_lblk, offsets,
961                                    &blocks_to_boundary);
962
963         if (depth == 0)
964                 goto out;
965
966         partial = ext4_get_branch(inode, depth, offsets, chain, &err);
967
968         /* Simplest case - block found, no allocation needed */
969         if (!partial) {
970                 first_block = le32_to_cpu(chain[depth - 1].key);
971                 count++;
972                 /*map more blocks*/
973                 while (count < map->m_len && count <= blocks_to_boundary) {
974                         ext4_fsblk_t blk;
975
976                         blk = le32_to_cpu(*(chain[depth-1].p + count));
977
978                         if (blk == first_block + count)
979                                 count++;
980                         else
981                                 break;
982                 }
983                 goto got_it;
984         }
985
986         /* Next simple case - plain lookup or failed read of indirect block */
987         if ((flags & EXT4_GET_BLOCKS_CREATE) == 0 || err == -EIO)
988                 goto cleanup;
989
990         /*
991          * Okay, we need to do block allocation.
992         */
993         goal = ext4_find_goal(inode, map->m_lblk, partial);
994
995         /* the number of blocks need to allocate for [d,t]indirect blocks */
996         indirect_blks = (chain + depth) - partial - 1;
997
998         /*
999          * Next look up the indirect map to count the totoal number of
1000          * direct blocks to allocate for this branch.
1001          */
1002         count = ext4_blks_to_allocate(partial, indirect_blks,
1003                                       map->m_len, blocks_to_boundary);
1004         /*
1005          * Block out ext4_truncate while we alter the tree
1006          */
1007         err = ext4_alloc_branch(handle, inode, map->m_lblk, indirect_blks,
1008                                 &count, goal,
1009                                 offsets + (partial - chain), partial);
1010
1011         /*
1012          * The ext4_splice_branch call will free and forget any buffers
1013          * on the new chain if there is a failure, but that risks using
1014          * up transaction credits, especially for bitmaps where the
1015          * credits cannot be returned.  Can we handle this somehow?  We
1016          * may need to return -EAGAIN upwards in the worst case.  --sct
1017          */
1018         if (!err)
1019                 err = ext4_splice_branch(handle, inode, map->m_lblk,
1020                                          partial, indirect_blks, count);
1021         if (err)
1022                 goto cleanup;
1023
1024         map->m_flags |= EXT4_MAP_NEW;
1025
1026         ext4_update_inode_fsync_trans(handle, inode, 1);
1027 got_it:
1028         map->m_flags |= EXT4_MAP_MAPPED;
1029         map->m_pblk = le32_to_cpu(chain[depth-1].key);
1030         map->m_len = count;
1031         if (count > blocks_to_boundary)
1032                 map->m_flags |= EXT4_MAP_BOUNDARY;
1033         err = count;
1034         /* Clean up and exit */
1035         partial = chain + depth - 1;    /* the whole chain */
1036 cleanup:
1037         while (partial > chain) {
1038                 BUFFER_TRACE(partial->bh, "call brelse");
1039                 brelse(partial->bh);
1040                 partial--;
1041         }
1042 out:
1043         return err;
1044 }
1045
1046 #ifdef CONFIG_QUOTA
1047 qsize_t *ext4_get_reserved_space(struct inode *inode)
1048 {
1049         return &EXT4_I(inode)->i_reserved_quota;
1050 }
1051 #endif
1052
1053 /*
1054  * Calculate the number of metadata blocks need to reserve
1055  * to allocate a new block at @lblocks for non extent file based file
1056  */
1057 static int ext4_indirect_calc_metadata_amount(struct inode *inode,
1058                                               sector_t lblock)
1059 {
1060         struct ext4_inode_info *ei = EXT4_I(inode);
1061         sector_t dind_mask = ~((sector_t)EXT4_ADDR_PER_BLOCK(inode->i_sb) - 1);
1062         int blk_bits;
1063
1064         if (lblock < EXT4_NDIR_BLOCKS)
1065                 return 0;
1066
1067         lblock -= EXT4_NDIR_BLOCKS;
1068
1069         if (ei->i_da_metadata_calc_len &&
1070             (lblock & dind_mask) == ei->i_da_metadata_calc_last_lblock) {
1071                 ei->i_da_metadata_calc_len++;
1072                 return 0;
1073         }
1074         ei->i_da_metadata_calc_last_lblock = lblock & dind_mask;
1075         ei->i_da_metadata_calc_len = 1;
1076         blk_bits = order_base_2(lblock);
1077         return (blk_bits / EXT4_ADDR_PER_BLOCK_BITS(inode->i_sb)) + 1;
1078 }
1079
1080 /*
1081  * Calculate the number of metadata blocks need to reserve
1082  * to allocate a block located at @lblock
1083  */
1084 static int ext4_calc_metadata_amount(struct inode *inode, sector_t lblock)
1085 {
1086         if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
1087                 return ext4_ext_calc_metadata_amount(inode, lblock);
1088
1089         return ext4_indirect_calc_metadata_amount(inode, lblock);
1090 }
1091
1092 /*
1093  * Called with i_data_sem down, which is important since we can call
1094  * ext4_discard_preallocations() from here.
1095  */
1096 void ext4_da_update_reserve_space(struct inode *inode,
1097                                         int used, int quota_claim)
1098 {
1099         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1100         struct ext4_inode_info *ei = EXT4_I(inode);
1101
1102         spin_lock(&ei->i_block_reservation_lock);
1103         trace_ext4_da_update_reserve_space(inode, used);
1104         if (unlikely(used > ei->i_reserved_data_blocks)) {
1105                 ext4_msg(inode->i_sb, KERN_NOTICE, "%s: ino %lu, used %d "
1106                          "with only %d reserved data blocks\n",
1107                          __func__, inode->i_ino, used,
1108                          ei->i_reserved_data_blocks);
1109                 WARN_ON(1);
1110                 used = ei->i_reserved_data_blocks;
1111         }
1112
1113         /* Update per-inode reservations */
1114         ei->i_reserved_data_blocks -= used;
1115         ei->i_reserved_meta_blocks -= ei->i_allocated_meta_blocks;
1116         percpu_counter_sub(&sbi->s_dirtyblocks_counter,
1117                            used + ei->i_allocated_meta_blocks);
1118         ei->i_allocated_meta_blocks = 0;
1119
1120         if (ei->i_reserved_data_blocks == 0) {
1121                 /*
1122                  * We can release all of the reserved metadata blocks
1123                  * only when we have written all of the delayed
1124                  * allocation blocks.
1125                  */
1126                 percpu_counter_sub(&sbi->s_dirtyblocks_counter,
1127                                    ei->i_reserved_meta_blocks);
1128                 ei->i_reserved_meta_blocks = 0;
1129                 ei->i_da_metadata_calc_len = 0;
1130         }
1131         spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
1132
1133         /* Update quota subsystem for data blocks */
1134         if (quota_claim)
1135                 dquot_claim_block(inode, used);
1136         else {
1137                 /*
1138                  * We did fallocate with an offset that is already delayed
1139                  * allocated. So on delayed allocated writeback we should
1140                  * not re-claim the quota for fallocated blocks.
1141                  */
1142                 dquot_release_reservation_block(inode, used);
1143         }
1144
1145         /*
1146          * If we have done all the pending block allocations and if
1147          * there aren't any writers on the inode, we can discard the
1148          * inode's preallocations.
1149          */
1150         if ((ei->i_reserved_data_blocks == 0) &&
1151             (atomic_read(&inode->i_writecount) == 0))
1152                 ext4_discard_preallocations(inode);
1153 }
1154
1155 static int __check_block_validity(struct inode *inode, const char *func,
1156                                 unsigned int line,
1157                                 struct ext4_map_blocks *map)
1158 {
1159         if (!ext4_data_block_valid(EXT4_SB(inode->i_sb), map->m_pblk,
1160                                    map->m_len)) {
1161                 ext4_error_inode(inode, func, line, map->m_pblk,
1162                                  "lblock %lu mapped to illegal pblock "
1163                                  "(length %d)", (unsigned long) map->m_lblk,
1164                                  map->m_len);
1165                 return -EIO;
1166         }
1167         return 0;
1168 }
1169
1170 #define check_block_validity(inode, map)        \
1171         __check_block_validity((inode), __func__, __LINE__, (map))
1172
1173 /*
1174  * Return the number of contiguous dirty pages in a given inode
1175  * starting at page frame idx.
1176  */
1177 static pgoff_t ext4_num_dirty_pages(struct inode *inode, pgoff_t idx,
1178                                     unsigned int max_pages)
1179 {
1180         struct address_space *mapping = inode->i_mapping;
1181         pgoff_t index;
1182         struct pagevec pvec;
1183         pgoff_t num = 0;
1184         int i, nr_pages, done = 0;
1185
1186         if (max_pages == 0)
1187                 return 0;
1188         pagevec_init(&pvec, 0);
1189         while (!done) {
1190                 index = idx;
1191                 nr_pages = pagevec_lookup_tag(&pvec, mapping, &index,
1192                                               PAGECACHE_TAG_DIRTY,
1193                                               (pgoff_t)PAGEVEC_SIZE);
1194                 if (nr_pages == 0)
1195                         break;
1196                 for (i = 0; i < nr_pages; i++) {
1197                         struct page *page = pvec.pages[i];
1198                         struct buffer_head *bh, *head;
1199
1200                         lock_page(page);
1201                         if (unlikely(page->mapping != mapping) ||
1202                             !PageDirty(page) ||
1203                             PageWriteback(page) ||
1204                             page->index != idx) {
1205                                 done = 1;
1206                                 unlock_page(page);
1207                                 break;
1208                         }
1209                         if (page_has_buffers(page)) {
1210                                 bh = head = page_buffers(page);
1211                                 do {
1212                                         if (!buffer_delay(bh) &&
1213                                             !buffer_unwritten(bh))
1214                                                 done = 1;
1215                                         bh = bh->b_this_page;
1216                                 } while (!done && (bh != head));
1217                         }
1218                         unlock_page(page);
1219                         if (done)
1220                                 break;
1221                         idx++;
1222                         num++;
1223                         if (num >= max_pages) {
1224                                 done = 1;
1225                                 break;
1226                         }
1227                 }
1228                 pagevec_release(&pvec);
1229         }
1230         return num;
1231 }
1232
1233 /*
1234  * The ext4_map_blocks() function tries to look up the requested blocks,
1235  * and returns if the blocks are already mapped.
1236  *
1237  * Otherwise it takes the write lock of the i_data_sem and allocate blocks
1238  * and store the allocated blocks in the result buffer head and mark it
1239  * mapped.
1240  *
1241  * If file type is extents based, it will call ext4_ext_map_blocks(),
1242  * Otherwise, call with ext4_ind_map_blocks() to handle indirect mapping
1243  * based files
1244  *
1245  * On success, it returns the number of blocks being mapped or allocate.
1246  * if create==0 and the blocks are pre-allocated and uninitialized block,
1247  * the result buffer head is unmapped. If the create ==1, it will make sure
1248  * the buffer head is mapped.
1249  *
1250  * It returns 0 if plain look up failed (blocks have not been allocated), in
1251  * that casem, buffer head is unmapped
1252  *
1253  * It returns the error in case of allocation failure.
1254  */
1255 int ext4_map_blocks(handle_t *handle, struct inode *inode,
1256                     struct ext4_map_blocks *map, int flags)
1257 {
1258         int retval;
1259
1260         map->m_flags = 0;
1261         ext_debug("ext4_map_blocks(): inode %lu, flag %d, max_blocks %u,"
1262                   "logical block %lu\n", inode->i_ino, flags, map->m_len,
1263                   (unsigned long) map->m_lblk);
1264         /*
1265          * Try to see if we can get the block without requesting a new
1266          * file system block.
1267          */
1268         down_read((&EXT4_I(inode)->i_data_sem));
1269         if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
1270                 retval = ext4_ext_map_blocks(handle, inode, map, 0);
1271         } else {
1272                 retval = ext4_ind_map_blocks(handle, inode, map, 0);
1273         }
1274         up_read((&EXT4_I(inode)->i_data_sem));
1275
1276         if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED) {
1277                 int ret = check_block_validity(inode, map);
1278                 if (ret != 0)
1279                         return ret;
1280         }
1281
1282         /* If it is only a block(s) look up */
1283         if ((flags & EXT4_GET_BLOCKS_CREATE) == 0)
1284                 return retval;
1285
1286         /*
1287          * Returns if the blocks have already allocated
1288          *
1289          * Note that if blocks have been preallocated
1290          * ext4_ext_get_block() returns th create = 0
1291          * with buffer head unmapped.
1292          */
1293         if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED)
1294                 return retval;
1295
1296         /*
1297          * When we call get_blocks without the create flag, the
1298          * BH_Unwritten flag could have gotten set if the blocks
1299          * requested were part of a uninitialized extent.  We need to
1300          * clear this flag now that we are committed to convert all or
1301          * part of the uninitialized extent to be an initialized
1302          * extent.  This is because we need to avoid the combination
1303          * of BH_Unwritten and BH_Mapped flags being simultaneously
1304          * set on the buffer_head.
1305          */
1306         map->m_flags &= ~EXT4_MAP_UNWRITTEN;
1307
1308         /*
1309          * New blocks allocate and/or writing to uninitialized extent
1310          * will possibly result in updating i_data, so we take
1311          * the write lock of i_data_sem, and call get_blocks()
1312          * with create == 1 flag.
1313          */
1314         down_write((&EXT4_I(inode)->i_data_sem));
1315
1316         /*
1317          * if the caller is from delayed allocation writeout path
1318          * we have already reserved fs blocks for allocation
1319          * let the underlying get_block() function know to
1320          * avoid double accounting
1321          */
1322         if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
1323                 EXT4_I(inode)->i_delalloc_reserved_flag = 1;
1324         /*
1325          * We need to check for EXT4 here because migrate
1326          * could have changed the inode type in between
1327          */
1328         if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
1329                 retval = ext4_ext_map_blocks(handle, inode, map, flags);
1330         } else {
1331                 retval = ext4_ind_map_blocks(handle, inode, map, flags);
1332
1333                 if (retval > 0 && map->m_flags & EXT4_MAP_NEW) {
1334                         /*
1335                          * We allocated new blocks which will result in
1336                          * i_data's format changing.  Force the migrate
1337                          * to fail by clearing migrate flags
1338                          */
1339                         ext4_clear_inode_state(inode, EXT4_STATE_EXT_MIGRATE);
1340                 }
1341
1342                 /*
1343                  * Update reserved blocks/metadata blocks after successful
1344                  * block allocation which had been deferred till now. We don't
1345                  * support fallocate for non extent files. So we can update
1346                  * reserve space here.
1347                  */
1348                 if ((retval > 0) &&
1349                         (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE))
1350                         ext4_da_update_reserve_space(inode, retval, 1);
1351         }
1352         if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
1353                 EXT4_I(inode)->i_delalloc_reserved_flag = 0;
1354
1355         up_write((&EXT4_I(inode)->i_data_sem));
1356         if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED) {
1357                 int ret = check_block_validity(inode, map);
1358                 if (ret != 0)
1359                         return ret;
1360         }
1361         return retval;
1362 }
1363
1364 /* Maximum number of blocks we map for direct IO at once. */
1365 #define DIO_MAX_BLOCKS 4096
1366
1367 static int _ext4_get_block(struct inode *inode, sector_t iblock,
1368                            struct buffer_head *bh, int flags)
1369 {
1370         handle_t *handle = ext4_journal_current_handle();
1371         struct ext4_map_blocks map;
1372         int ret = 0, started = 0;
1373         int dio_credits;
1374
1375         map.m_lblk = iblock;
1376         map.m_len = bh->b_size >> inode->i_blkbits;
1377
1378         if (flags && !handle) {
1379                 /* Direct IO write... */
1380                 if (map.m_len > DIO_MAX_BLOCKS)
1381                         map.m_len = DIO_MAX_BLOCKS;
1382                 dio_credits = ext4_chunk_trans_blocks(inode, map.m_len);
1383                 handle = ext4_journal_start(inode, dio_credits);
1384                 if (IS_ERR(handle)) {
1385                         ret = PTR_ERR(handle);
1386                         return ret;
1387                 }
1388                 started = 1;
1389         }
1390
1391         ret = ext4_map_blocks(handle, inode, &map, flags);
1392         if (ret > 0) {
1393                 map_bh(bh, inode->i_sb, map.m_pblk);
1394                 bh->b_state = (bh->b_state & ~EXT4_MAP_FLAGS) | map.m_flags;
1395                 bh->b_size = inode->i_sb->s_blocksize * map.m_len;
1396                 ret = 0;
1397         }
1398         if (started)
1399                 ext4_journal_stop(handle);
1400         return ret;
1401 }
1402
1403 int ext4_get_block(struct inode *inode, sector_t iblock,
1404                    struct buffer_head *bh, int create)
1405 {
1406         return _ext4_get_block(inode, iblock, bh,
1407                                create ? EXT4_GET_BLOCKS_CREATE : 0);
1408 }
1409
1410 /*
1411  * `handle' can be NULL if create is zero
1412  */
1413 struct buffer_head *ext4_getblk(handle_t *handle, struct inode *inode,
1414                                 ext4_lblk_t block, int create, int *errp)
1415 {
1416         struct ext4_map_blocks map;
1417         struct buffer_head *bh;
1418         int fatal = 0, err;
1419
1420         J_ASSERT(handle != NULL || create == 0);
1421
1422         map.m_lblk = block;
1423         map.m_len = 1;
1424         err = ext4_map_blocks(handle, inode, &map,
1425                               create ? EXT4_GET_BLOCKS_CREATE : 0);
1426
1427         if (err < 0)
1428                 *errp = err;
1429         if (err <= 0)
1430                 return NULL;
1431         *errp = 0;
1432
1433         bh = sb_getblk(inode->i_sb, map.m_pblk);
1434         if (!bh) {
1435                 *errp = -EIO;
1436                 return NULL;
1437         }
1438         if (map.m_flags & EXT4_MAP_NEW) {
1439                 J_ASSERT(create != 0);
1440                 J_ASSERT(handle != NULL);
1441
1442                 /*
1443                  * Now that we do not always journal data, we should
1444                  * keep in mind whether this should always journal the
1445                  * new buffer as metadata.  For now, regular file
1446                  * writes use ext4_get_block instead, so it's not a
1447                  * problem.
1448                  */
1449                 lock_buffer(bh);
1450                 BUFFER_TRACE(bh, "call get_create_access");
1451                 fatal = ext4_journal_get_create_access(handle, bh);
1452                 if (!fatal && !buffer_uptodate(bh)) {
1453                         memset(bh->b_data, 0, inode->i_sb->s_blocksize);
1454                         set_buffer_uptodate(bh);
1455                 }
1456                 unlock_buffer(bh);
1457                 BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
1458                 err = ext4_handle_dirty_metadata(handle, inode, bh);
1459                 if (!fatal)
1460                         fatal = err;
1461         } else {
1462                 BUFFER_TRACE(bh, "not a new buffer");
1463         }
1464         if (fatal) {
1465                 *errp = fatal;
1466                 brelse(bh);
1467                 bh = NULL;
1468         }
1469         return bh;
1470 }
1471
1472 struct buffer_head *ext4_bread(handle_t *handle, struct inode *inode,
1473                                ext4_lblk_t block, int create, int *err)
1474 {
1475         struct buffer_head *bh;
1476
1477         bh = ext4_getblk(handle, inode, block, create, err);
1478         if (!bh)
1479                 return bh;
1480         if (buffer_uptodate(bh))
1481                 return bh;
1482         ll_rw_block(READ_META, 1, &bh);
1483         wait_on_buffer(bh);
1484         if (buffer_uptodate(bh))
1485                 return bh;
1486         put_bh(bh);
1487         *err = -EIO;
1488         return NULL;
1489 }
1490
1491 static int walk_page_buffers(handle_t *handle,
1492                              struct buffer_head *head,
1493                              unsigned from,
1494                              unsigned to,
1495                              int *partial,
1496                              int (*fn)(handle_t *handle,
1497                                        struct buffer_head *bh))
1498 {
1499         struct buffer_head *bh;
1500         unsigned block_start, block_end;
1501         unsigned blocksize = head->b_size;
1502         int err, ret = 0;
1503         struct buffer_head *next;
1504
1505         for (bh = head, block_start = 0;
1506              ret == 0 && (bh != head || !block_start);
1507              block_start = block_end, bh = next) {
1508                 next = bh->b_this_page;
1509                 block_end = block_start + blocksize;
1510                 if (block_end <= from || block_start >= to) {
1511                         if (partial && !buffer_uptodate(bh))
1512                                 *partial = 1;
1513                         continue;
1514                 }
1515                 err = (*fn)(handle, bh);
1516                 if (!ret)
1517                         ret = err;
1518         }
1519         return ret;
1520 }
1521
1522 /*
1523  * To preserve ordering, it is essential that the hole instantiation and
1524  * the data write be encapsulated in a single transaction.  We cannot
1525  * close off a transaction and start a new one between the ext4_get_block()
1526  * and the commit_write().  So doing the jbd2_journal_start at the start of
1527  * prepare_write() is the right place.
1528  *
1529  * Also, this function can nest inside ext4_writepage() ->
1530  * block_write_full_page(). In that case, we *know* that ext4_writepage()
1531  * has generated enough buffer credits to do the whole page.  So we won't
1532  * block on the journal in that case, which is good, because the caller may
1533  * be PF_MEMALLOC.
1534  *
1535  * By accident, ext4 can be reentered when a transaction is open via
1536  * quota file writes.  If we were to commit the transaction while thus
1537  * reentered, there can be a deadlock - we would be holding a quota
1538  * lock, and the commit would never complete if another thread had a
1539  * transaction open and was blocking on the quota lock - a ranking
1540  * violation.
1541  *
1542  * So what we do is to rely on the fact that jbd2_journal_stop/journal_start
1543  * will _not_ run commit under these circumstances because handle->h_ref
1544  * is elevated.  We'll still have enough credits for the tiny quotafile
1545  * write.
1546  */
1547 static int do_journal_get_write_access(handle_t *handle,
1548                                        struct buffer_head *bh)
1549 {
1550         int dirty = buffer_dirty(bh);
1551         int ret;
1552
1553         if (!buffer_mapped(bh) || buffer_freed(bh))
1554                 return 0;
1555         /*
1556          * __block_write_begin() could have dirtied some buffers. Clean
1557          * the dirty bit as jbd2_journal_get_write_access() could complain
1558          * otherwise about fs integrity issues. Setting of the dirty bit
1559          * by __block_write_begin() isn't a real problem here as we clear
1560          * the bit before releasing a page lock and thus writeback cannot
1561          * ever write the buffer.
1562          */
1563         if (dirty)
1564                 clear_buffer_dirty(bh);
1565         ret = ext4_journal_get_write_access(handle, bh);
1566         if (!ret && dirty)
1567                 ret = ext4_handle_dirty_metadata(handle, NULL, bh);
1568         return ret;
1569 }
1570
1571 /*
1572  * Truncate blocks that were not used by write. We have to truncate the
1573  * pagecache as well so that corresponding buffers get properly unmapped.
1574  */
1575 static void ext4_truncate_failed_write(struct inode *inode)
1576 {
1577         truncate_inode_pages(inode->i_mapping, inode->i_size);
1578         ext4_truncate(inode);
1579 }
1580
1581 static int ext4_get_block_write(struct inode *inode, sector_t iblock,
1582                    struct buffer_head *bh_result, int create);
1583 static int ext4_write_begin(struct file *file, struct address_space *mapping,
1584                             loff_t pos, unsigned len, unsigned flags,
1585                             struct page **pagep, void **fsdata)
1586 {
1587         struct inode *inode = mapping->host;
1588         int ret, needed_blocks;
1589         handle_t *handle;
1590         int retries = 0;
1591         struct page *page;
1592         pgoff_t index;
1593         unsigned from, to;
1594
1595         trace_ext4_write_begin(inode, pos, len, flags);
1596         /*
1597          * Reserve one block more for addition to orphan list in case
1598          * we allocate blocks but write fails for some reason
1599          */
1600         needed_blocks = ext4_writepage_trans_blocks(inode) + 1;
1601         index = pos >> PAGE_CACHE_SHIFT;
1602         from = pos & (PAGE_CACHE_SIZE - 1);
1603         to = from + len;
1604
1605 retry:
1606         handle = ext4_journal_start(inode, needed_blocks);
1607         if (IS_ERR(handle)) {
1608                 ret = PTR_ERR(handle);
1609                 goto out;
1610         }
1611
1612         /* We cannot recurse into the filesystem as the transaction is already
1613          * started */
1614         flags |= AOP_FLAG_NOFS;
1615
1616         page = grab_cache_page_write_begin(mapping, index, flags);
1617         if (!page) {
1618                 ext4_journal_stop(handle);
1619                 ret = -ENOMEM;
1620                 goto out;
1621         }
1622         *pagep = page;
1623
1624         if (ext4_should_dioread_nolock(inode))
1625                 ret = __block_write_begin(page, pos, len, ext4_get_block_write);
1626         else
1627                 ret = __block_write_begin(page, pos, len, ext4_get_block);
1628
1629         if (!ret && ext4_should_journal_data(inode)) {
1630                 ret = walk_page_buffers(handle, page_buffers(page),
1631                                 from, to, NULL, do_journal_get_write_access);
1632         }
1633
1634         if (ret) {
1635                 unlock_page(page);
1636                 page_cache_release(page);
1637                 /*
1638                  * __block_write_begin may have instantiated a few blocks
1639                  * outside i_size.  Trim these off again. Don't need
1640                  * i_size_read because we hold i_mutex.
1641                  *
1642                  * Add inode to orphan list in case we crash before
1643                  * truncate finishes
1644                  */
1645                 if (pos + len > inode->i_size && ext4_can_truncate(inode))
1646                         ext4_orphan_add(handle, inode);
1647
1648                 ext4_journal_stop(handle);
1649                 if (pos + len > inode->i_size) {
1650                         ext4_truncate_failed_write(inode);
1651                         /*
1652                          * If truncate failed early the inode might
1653                          * still be on the orphan list; we need to
1654                          * make sure the inode is removed from the
1655                          * orphan list in that case.
1656                          */
1657                         if (inode->i_nlink)
1658                                 ext4_orphan_del(NULL, inode);
1659                 }
1660         }
1661
1662         if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
1663                 goto retry;
1664 out:
1665         return ret;
1666 }
1667
1668 /* For write_end() in data=journal mode */
1669 static int write_end_fn(handle_t *handle, struct buffer_head *bh)
1670 {
1671         if (!buffer_mapped(bh) || buffer_freed(bh))
1672                 return 0;
1673         set_buffer_uptodate(bh);
1674         return ext4_handle_dirty_metadata(handle, NULL, bh);
1675 }
1676
1677 static int ext4_generic_write_end(struct file *file,
1678                                   struct address_space *mapping,
1679                                   loff_t pos, unsigned len, unsigned copied,
1680                                   struct page *page, void *fsdata)
1681 {
1682         int i_size_changed = 0;
1683         struct inode *inode = mapping->host;
1684         handle_t *handle = ext4_journal_current_handle();
1685
1686         copied = block_write_end(file, mapping, pos, len, copied, page, fsdata);
1687
1688         /*
1689          * No need to use i_size_read() here, the i_size
1690          * cannot change under us because we hold i_mutex.
1691          *
1692          * But it's important to update i_size while still holding page lock:
1693          * page writeout could otherwise come in and zero beyond i_size.
1694          */
1695         if (pos + copied > inode->i_size) {
1696                 i_size_write(inode, pos + copied);
1697                 i_size_changed = 1;
1698         }
1699
1700         if (pos + copied >  EXT4_I(inode)->i_disksize) {
1701                 /* We need to mark inode dirty even if
1702                  * new_i_size is less that inode->i_size
1703                  * bu greater than i_disksize.(hint delalloc)
1704                  */
1705                 ext4_update_i_disksize(inode, (pos + copied));
1706                 i_size_changed = 1;
1707         }
1708         unlock_page(page);
1709         page_cache_release(page);
1710
1711         /*
1712          * Don't mark the inode dirty under page lock. First, it unnecessarily
1713          * makes the holding time of page lock longer. Second, it forces lock
1714          * ordering of page lock and transaction start for journaling
1715          * filesystems.
1716          */
1717         if (i_size_changed)
1718                 ext4_mark_inode_dirty(handle, inode);
1719
1720         return copied;
1721 }
1722
1723 /*
1724  * We need to pick up the new inode size which generic_commit_write gave us
1725  * `file' can be NULL - eg, when called from page_symlink().
1726  *
1727  * ext4 never places buffers on inode->i_mapping->private_list.  metadata
1728  * buffers are managed internally.
1729  */
1730 static int ext4_ordered_write_end(struct file *file,
1731                                   struct address_space *mapping,
1732                                   loff_t pos, unsigned len, unsigned copied,
1733                                   struct page *page, void *fsdata)
1734 {
1735         handle_t *handle = ext4_journal_current_handle();
1736         struct inode *inode = mapping->host;
1737         int ret = 0, ret2;
1738
1739         trace_ext4_ordered_write_end(inode, pos, len, copied);
1740         ret = ext4_jbd2_file_inode(handle, inode);
1741
1742         if (ret == 0) {
1743                 ret2 = ext4_generic_write_end(file, mapping, pos, len, copied,
1744                                                         page, fsdata);
1745                 copied = ret2;
1746                 if (pos + len > inode->i_size && ext4_can_truncate(inode))
1747                         /* if we have allocated more blocks and copied
1748                          * less. We will have blocks allocated outside
1749                          * inode->i_size. So truncate them
1750                          */
1751                         ext4_orphan_add(handle, inode);
1752                 if (ret2 < 0)
1753                         ret = ret2;
1754         }
1755         ret2 = ext4_journal_stop(handle);
1756         if (!ret)
1757                 ret = ret2;
1758
1759         if (pos + len > inode->i_size) {
1760                 ext4_truncate_failed_write(inode);
1761                 /*
1762                  * If truncate failed early the inode might still be
1763                  * on the orphan list; we need to make sure the inode
1764                  * is removed from the orphan list in that case.
1765                  */
1766                 if (inode->i_nlink)
1767                         ext4_orphan_del(NULL, inode);
1768         }
1769
1770
1771         return ret ? ret : copied;
1772 }
1773
1774 static int ext4_writeback_write_end(struct file *file,
1775                                     struct address_space *mapping,
1776                                     loff_t pos, unsigned len, unsigned copied,
1777                                     struct page *page, void *fsdata)
1778 {
1779         handle_t *handle = ext4_journal_current_handle();
1780         struct inode *inode = mapping->host;
1781         int ret = 0, ret2;
1782
1783         trace_ext4_writeback_write_end(inode, pos, len, copied);
1784         ret2 = ext4_generic_write_end(file, mapping, pos, len, copied,
1785                                                         page, fsdata);
1786         copied = ret2;
1787         if (pos + len > inode->i_size && ext4_can_truncate(inode))
1788                 /* if we have allocated more blocks and copied
1789                  * less. We will have blocks allocated outside
1790                  * inode->i_size. So truncate them
1791                  */
1792                 ext4_orphan_add(handle, inode);
1793
1794         if (ret2 < 0)
1795                 ret = ret2;
1796
1797         ret2 = ext4_journal_stop(handle);
1798         if (!ret)
1799                 ret = ret2;
1800
1801         if (pos + len > inode->i_size) {
1802                 ext4_truncate_failed_write(inode);
1803                 /*
1804                  * If truncate failed early the inode might still be
1805                  * on the orphan list; we need to make sure the inode
1806                  * is removed from the orphan list in that case.
1807                  */
1808                 if (inode->i_nlink)
1809                         ext4_orphan_del(NULL, inode);
1810         }
1811
1812         return ret ? ret : copied;
1813 }
1814
1815 static int ext4_journalled_write_end(struct file *file,
1816                                      struct address_space *mapping,
1817                                      loff_t pos, unsigned len, unsigned copied,
1818                                      struct page *page, void *fsdata)
1819 {
1820         handle_t *handle = ext4_journal_current_handle();
1821         struct inode *inode = mapping->host;
1822         int ret = 0, ret2;
1823         int partial = 0;
1824         unsigned from, to;
1825         loff_t new_i_size;
1826
1827         trace_ext4_journalled_write_end(inode, pos, len, copied);
1828         from = pos & (PAGE_CACHE_SIZE - 1);
1829         to = from + len;
1830
1831         if (copied < len) {
1832                 if (!PageUptodate(page))
1833                         copied = 0;
1834                 page_zero_new_buffers(page, from+copied, to);
1835         }
1836
1837         ret = walk_page_buffers(handle, page_buffers(page), from,
1838                                 to, &partial, write_end_fn);
1839         if (!partial)
1840                 SetPageUptodate(page);
1841         new_i_size = pos + copied;
1842         if (new_i_size > inode->i_size)
1843                 i_size_write(inode, pos+copied);
1844         ext4_set_inode_state(inode, EXT4_STATE_JDATA);
1845         if (new_i_size > EXT4_I(inode)->i_disksize) {
1846                 ext4_update_i_disksize(inode, new_i_size);
1847                 ret2 = ext4_mark_inode_dirty(handle, inode);
1848                 if (!ret)
1849                         ret = ret2;
1850         }
1851
1852         unlock_page(page);
1853         page_cache_release(page);
1854         if (pos + len > inode->i_size && ext4_can_truncate(inode))
1855                 /* if we have allocated more blocks and copied
1856                  * less. We will have blocks allocated outside
1857                  * inode->i_size. So truncate them
1858                  */
1859                 ext4_orphan_add(handle, inode);
1860
1861         ret2 = ext4_journal_stop(handle);
1862         if (!ret)
1863                 ret = ret2;
1864         if (pos + len > inode->i_size) {
1865                 ext4_truncate_failed_write(inode);
1866                 /*
1867                  * If truncate failed early the inode might still be
1868                  * on the orphan list; we need to make sure the inode
1869                  * is removed from the orphan list in that case.
1870                  */
1871                 if (inode->i_nlink)
1872                         ext4_orphan_del(NULL, inode);
1873         }
1874
1875         return ret ? ret : copied;
1876 }
1877
1878 /*
1879  * Reserve a single block located at lblock
1880  */
1881 static int ext4_da_reserve_space(struct inode *inode, sector_t lblock)
1882 {
1883         int retries = 0;
1884         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1885         struct ext4_inode_info *ei = EXT4_I(inode);
1886         unsigned long md_needed;
1887         int ret;
1888
1889         /*
1890          * recalculate the amount of metadata blocks to reserve
1891          * in order to allocate nrblocks
1892          * worse case is one extent per block
1893          */
1894 repeat:
1895         spin_lock(&ei->i_block_reservation_lock);
1896         md_needed = ext4_calc_metadata_amount(inode, lblock);
1897         trace_ext4_da_reserve_space(inode, md_needed);
1898         spin_unlock(&ei->i_block_reservation_lock);
1899
1900         /*
1901          * We will charge metadata quota at writeout time; this saves
1902          * us from metadata over-estimation, though we may go over by
1903          * a small amount in the end.  Here we just reserve for data.
1904          */
1905         ret = dquot_reserve_block(inode, 1);
1906         if (ret)
1907                 return ret;
1908         /*
1909          * We do still charge estimated metadata to the sb though;
1910          * we cannot afford to run out of free blocks.
1911          */
1912         if (ext4_claim_free_blocks(sbi, md_needed + 1)) {
1913                 dquot_release_reservation_block(inode, 1);
1914                 if (ext4_should_retry_alloc(inode->i_sb, &retries)) {
1915                         yield();
1916                         goto repeat;
1917                 }
1918                 return -ENOSPC;
1919         }
1920         spin_lock(&ei->i_block_reservation_lock);
1921         ei->i_reserved_data_blocks++;
1922         ei->i_reserved_meta_blocks += md_needed;
1923         spin_unlock(&ei->i_block_reservation_lock);
1924
1925         return 0;       /* success */
1926 }
1927
1928 static void ext4_da_release_space(struct inode *inode, int to_free)
1929 {
1930         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1931         struct ext4_inode_info *ei = EXT4_I(inode);
1932
1933         if (!to_free)
1934                 return;         /* Nothing to release, exit */
1935
1936         spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
1937
1938         trace_ext4_da_release_space(inode, to_free);
1939         if (unlikely(to_free > ei->i_reserved_data_blocks)) {
1940                 /*
1941                  * if there aren't enough reserved blocks, then the
1942                  * counter is messed up somewhere.  Since this
1943                  * function is called from invalidate page, it's
1944                  * harmless to return without any action.
1945                  */
1946                 ext4_msg(inode->i_sb, KERN_NOTICE, "ext4_da_release_space: "
1947                          "ino %lu, to_free %d with only %d reserved "
1948                          "data blocks\n", inode->i_ino, to_free,
1949                          ei->i_reserved_data_blocks);
1950                 WARN_ON(1);
1951                 to_free = ei->i_reserved_data_blocks;
1952         }
1953         ei->i_reserved_data_blocks -= to_free;
1954
1955         if (ei->i_reserved_data_blocks == 0) {
1956                 /*
1957                  * We can release all of the reserved metadata blocks
1958                  * only when we have written all of the delayed
1959                  * allocation blocks.
1960                  */
1961                 percpu_counter_sub(&sbi->s_dirtyblocks_counter,
1962                                    ei->i_reserved_meta_blocks);
1963                 ei->i_reserved_meta_blocks = 0;
1964                 ei->i_da_metadata_calc_len = 0;
1965         }
1966
1967         /* update fs dirty data blocks counter */
1968         percpu_counter_sub(&sbi->s_dirtyblocks_counter, to_free);
1969
1970         spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
1971
1972         dquot_release_reservation_block(inode, to_free);
1973 }
1974
1975 static void ext4_da_page_release_reservation(struct page *page,
1976                                              unsigned long offset)
1977 {
1978         int to_release = 0;
1979         struct buffer_head *head, *bh;
1980         unsigned int curr_off = 0;
1981
1982         head = page_buffers(page);
1983         bh = head;
1984         do {
1985                 unsigned int next_off = curr_off + bh->b_size;
1986
1987                 if ((offset <= curr_off) && (buffer_delay(bh))) {
1988                         to_release++;
1989                         clear_buffer_delay(bh);
1990                 }
1991                 curr_off = next_off;
1992         } while ((bh = bh->b_this_page) != head);
1993         ext4_da_release_space(page->mapping->host, to_release);
1994 }
1995
1996 /*
1997  * Delayed allocation stuff
1998  */
1999
2000 /*
2001  * mpage_da_submit_io - walks through extent of pages and try to write
2002  * them with writepage() call back
2003  *
2004  * @mpd->inode: inode
2005  * @mpd->first_page: first page of the extent
2006  * @mpd->next_page: page after the last page of the extent
2007  *
2008  * By the time mpage_da_submit_io() is called we expect all blocks
2009  * to be allocated. this may be wrong if allocation failed.
2010  *
2011  * As pages are already locked by write_cache_pages(), we can't use it
2012  */
2013 static int mpage_da_submit_io(struct mpage_da_data *mpd,
2014                               struct ext4_map_blocks *map)
2015 {
2016         struct pagevec pvec;
2017         unsigned long index, end;
2018         int ret = 0, err, nr_pages, i;
2019         struct inode *inode = mpd->inode;
2020         struct address_space *mapping = inode->i_mapping;
2021         loff_t size = i_size_read(inode);
2022         unsigned int len, block_start;
2023         struct buffer_head *bh, *page_bufs = NULL;
2024         int journal_data = ext4_should_journal_data(inode);
2025         sector_t pblock = 0, cur_logical = 0;
2026         struct ext4_io_submit io_submit;
2027
2028         BUG_ON(mpd->next_page <= mpd->first_page);
2029         memset(&io_submit, 0, sizeof(io_submit));
2030         /*
2031          * We need to start from the first_page to the next_page - 1
2032          * to make sure we also write the mapped dirty buffer_heads.
2033          * If we look at mpd->b_blocknr we would only be looking
2034          * at the currently mapped buffer_heads.
2035          */
2036         index = mpd->first_page;
2037         end = mpd->next_page - 1;
2038
2039         pagevec_init(&pvec, 0);
2040         while (index <= end) {
2041                 nr_pages = pagevec_lookup(&pvec, mapping, index, PAGEVEC_SIZE);
2042                 if (nr_pages == 0)
2043                         break;
2044                 for (i = 0; i < nr_pages; i++) {
2045                         int commit_write = 0, redirty_page = 0;
2046                         struct page *page = pvec.pages[i];
2047
2048                         index = page->index;
2049                         if (index > end)
2050                                 break;
2051
2052                         if (index == size >> PAGE_CACHE_SHIFT)
2053                                 len = size & ~PAGE_CACHE_MASK;
2054                         else
2055                                 len = PAGE_CACHE_SIZE;
2056                         if (map) {
2057                                 cur_logical = index << (PAGE_CACHE_SHIFT -
2058                                                         inode->i_blkbits);
2059                                 pblock = map->m_pblk + (cur_logical -
2060                                                         map->m_lblk);
2061                         }
2062                         index++;
2063
2064                         BUG_ON(!PageLocked(page));
2065                         BUG_ON(PageWriteback(page));
2066
2067                         /*
2068                          * If the page does not have buffers (for
2069                          * whatever reason), try to create them using
2070                          * __block_write_begin.  If this fails,
2071                          * redirty the page and move on.
2072                          */
2073                         if (!page_has_buffers(page)) {
2074                                 if (__block_write_begin(page, 0, len,
2075                                                 noalloc_get_block_write)) {
2076                                 redirty_page:
2077                                         redirty_page_for_writepage(mpd->wbc,
2078                                                                    page);
2079                                         unlock_page(page);
2080                                         continue;
2081                                 }
2082                                 commit_write = 1;
2083                         }
2084
2085                         bh = page_bufs = page_buffers(page);
2086                         block_start = 0;
2087                         do {
2088                                 if (!bh)
2089                                         goto redirty_page;
2090                                 if (map && (cur_logical >= map->m_lblk) &&
2091                                     (cur_logical <= (map->m_lblk +
2092                                                      (map->m_len - 1)))) {
2093                                         if (buffer_delay(bh)) {
2094                                                 clear_buffer_delay(bh);
2095                                                 bh->b_blocknr = pblock;
2096                                         }
2097                                         if (buffer_unwritten(bh) ||
2098                                             buffer_mapped(bh))
2099                                                 BUG_ON(bh->b_blocknr != pblock);
2100                                         if (map->m_flags & EXT4_MAP_UNINIT)
2101                                                 set_buffer_uninit(bh);
2102                                         clear_buffer_unwritten(bh);
2103                                 }
2104
2105                                 /* redirty page if block allocation undone */
2106                                 if (buffer_delay(bh) || buffer_unwritten(bh))
2107                                         redirty_page = 1;
2108                                 bh = bh->b_this_page;
2109                                 block_start += bh->b_size;
2110                                 cur_logical++;
2111                                 pblock++;
2112                         } while (bh != page_bufs);
2113
2114                         if (redirty_page)
2115                                 goto redirty_page;
2116
2117                         if (commit_write)
2118                                 /* mark the buffer_heads as dirty & uptodate */
2119                                 block_commit_write(page, 0, len);
2120
2121                         /*
2122                          * Delalloc doesn't support data journalling,
2123                          * but eventually maybe we'll lift this
2124                          * restriction.
2125                          */
2126                         if (unlikely(journal_data && PageChecked(page)))
2127                                 err = __ext4_journalled_writepage(page, len);
2128                         else
2129                                 err = ext4_bio_write_page(&io_submit, page,
2130                                                           len, mpd->wbc);
2131
2132                         if (!err)
2133                                 mpd->pages_written++;
2134                         /*
2135                          * In error case, we have to continue because
2136                          * remaining pages are still locked
2137                          */
2138                         if (ret == 0)
2139                                 ret = err;
2140                 }
2141                 pagevec_release(&pvec);
2142         }
2143         ext4_io_submit(&io_submit);
2144         return ret;
2145 }
2146
2147 static void ext4_da_block_invalidatepages(struct mpage_da_data *mpd,
2148                                         sector_t logical, long blk_cnt)
2149 {
2150         int nr_pages, i;
2151         pgoff_t index, end;
2152         struct pagevec pvec;
2153         struct inode *inode = mpd->inode;
2154         struct address_space *mapping = inode->i_mapping;
2155
2156         index = logical >> (PAGE_CACHE_SHIFT - inode->i_blkbits);
2157         end   = (logical + blk_cnt - 1) >>
2158                                 (PAGE_CACHE_SHIFT - inode->i_blkbits);
2159         while (index <= end) {
2160                 nr_pages = pagevec_lookup(&pvec, mapping, index, PAGEVEC_SIZE);
2161                 if (nr_pages == 0)
2162                         break;
2163                 for (i = 0; i < nr_pages; i++) {
2164                         struct page *page = pvec.pages[i];
2165                         if (page->index > end)
2166                                 break;
2167                         BUG_ON(!PageLocked(page));
2168                         BUG_ON(PageWriteback(page));
2169                         block_invalidatepage(page, 0);
2170                         ClearPageUptodate(page);
2171                         unlock_page(page);
2172                 }
2173                 index = pvec.pages[nr_pages - 1]->index + 1;
2174                 pagevec_release(&pvec);
2175         }
2176         return;
2177 }
2178
2179 static void ext4_print_free_blocks(struct inode *inode)
2180 {
2181         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2182         printk(KERN_CRIT "Total free blocks count %lld\n",
2183                ext4_count_free_blocks(inode->i_sb));
2184         printk(KERN_CRIT "Free/Dirty block details\n");
2185         printk(KERN_CRIT "free_blocks=%lld\n",
2186                (long long) percpu_counter_sum(&sbi->s_freeblocks_counter));
2187         printk(KERN_CRIT "dirty_blocks=%lld\n",
2188                (long long) percpu_counter_sum(&sbi->s_dirtyblocks_counter));
2189         printk(KERN_CRIT "Block reservation details\n");
2190         printk(KERN_CRIT "i_reserved_data_blocks=%u\n",
2191                EXT4_I(inode)->i_reserved_data_blocks);
2192         printk(KERN_CRIT "i_reserved_meta_blocks=%u\n",
2193                EXT4_I(inode)->i_reserved_meta_blocks);
2194         return;
2195 }
2196
2197 /*
2198  * mpage_da_map_and_submit - go through given space, map them
2199  *       if necessary, and then submit them for I/O
2200  *
2201  * @mpd - bh describing space
2202  *
2203  * The function skips space we know is already mapped to disk blocks.
2204  *
2205  */
2206 static void mpage_da_map_and_submit(struct mpage_da_data *mpd)
2207 {
2208         int err, blks, get_blocks_flags;
2209         struct ext4_map_blocks map, *mapp = NULL;
2210         sector_t next = mpd->b_blocknr;
2211         unsigned max_blocks = mpd->b_size >> mpd->inode->i_blkbits;
2212         loff_t disksize = EXT4_I(mpd->inode)->i_disksize;
2213         handle_t *handle = NULL;
2214
2215         /*
2216          * If the blocks are mapped already, or we couldn't accumulate
2217          * any blocks, then proceed immediately to the submission stage.
2218          */
2219         if ((mpd->b_size == 0) ||
2220             ((mpd->b_state  & (1 << BH_Mapped)) &&
2221              !(mpd->b_state & (1 << BH_Delay)) &&
2222              !(mpd->b_state & (1 << BH_Unwritten))))
2223                 goto submit_io;
2224
2225         handle = ext4_journal_current_handle();
2226         BUG_ON(!handle);
2227
2228         /*
2229          * Call ext4_map_blocks() to allocate any delayed allocation
2230          * blocks, or to convert an uninitialized extent to be
2231          * initialized (in the case where we have written into
2232          * one or more preallocated blocks).
2233          *
2234          * We pass in the magic EXT4_GET_BLOCKS_DELALLOC_RESERVE to
2235          * indicate that we are on the delayed allocation path.  This
2236          * affects functions in many different parts of the allocation
2237          * call path.  This flag exists primarily because we don't
2238          * want to change *many* call functions, so ext4_map_blocks()
2239          * will set the magic i_delalloc_reserved_flag once the
2240          * inode's allocation semaphore is taken.
2241          *
2242          * If the blocks in questions were delalloc blocks, set
2243          * EXT4_GET_BLOCKS_DELALLOC_RESERVE so the delalloc accounting
2244          * variables are updated after the blocks have been allocated.
2245          */
2246         map.m_lblk = next;
2247         map.m_len = max_blocks;
2248         get_blocks_flags = EXT4_GET_BLOCKS_CREATE;
2249         if (ext4_should_dioread_nolock(mpd->inode))
2250                 get_blocks_flags |= EXT4_GET_BLOCKS_IO_CREATE_EXT;
2251         if (mpd->b_state & (1 << BH_Delay))
2252                 get_blocks_flags |= EXT4_GET_BLOCKS_DELALLOC_RESERVE;
2253
2254         blks = ext4_map_blocks(handle, mpd->inode, &map, get_blocks_flags);
2255         if (blks < 0) {
2256                 struct super_block *sb = mpd->inode->i_sb;
2257
2258                 err = blks;
2259                 /*
2260                  * If get block returns EAGAIN or ENOSPC and there
2261                  * appears to be free blocks we will call
2262                  * ext4_writepage() for all of the pages which will
2263                  * just redirty the pages.
2264                  */
2265                 if (err == -EAGAIN)
2266                         goto submit_io;
2267
2268                 if (err == -ENOSPC &&
2269                     ext4_count_free_blocks(sb)) {
2270                         mpd->retval = err;
2271                         goto submit_io;
2272                 }
2273
2274                 /*
2275                  * get block failure will cause us to loop in
2276                  * writepages, because a_ops->writepage won't be able
2277                  * to make progress. The page will be redirtied by
2278                  * writepage and writepages will again try to write
2279                  * the same.
2280                  */
2281                 if (!(EXT4_SB(sb)->s_mount_flags & EXT4_MF_FS_ABORTED)) {
2282                         ext4_msg(sb, KERN_CRIT,
2283                                  "delayed block allocation failed for inode %lu "
2284                                  "at logical offset %llu with max blocks %zd "
2285                                  "with error %d", mpd->inode->i_ino,
2286                                  (unsigned long long) next,
2287                                  mpd->b_size >> mpd->inode->i_blkbits, err);
2288                         ext4_msg(sb, KERN_CRIT,
2289                                 "This should not happen!! Data will be lost\n");
2290                         if (err == -ENOSPC)
2291                                 ext4_print_free_blocks(mpd->inode);
2292                 }
2293                 /* invalidate all the pages */
2294                 ext4_da_block_invalidatepages(mpd, next,
2295                                 mpd->b_size >> mpd->inode->i_blkbits);
2296                 return;
2297         }
2298         BUG_ON(blks == 0);
2299
2300         mapp = &map;
2301         if (map.m_flags & EXT4_MAP_NEW) {
2302                 struct block_device *bdev = mpd->inode->i_sb->s_bdev;
2303                 int i;
2304
2305                 for (i = 0; i < map.m_len; i++)
2306                         unmap_underlying_metadata(bdev, map.m_pblk + i);
2307         }
2308
2309         if (ext4_should_order_data(mpd->inode)) {
2310                 err = ext4_jbd2_file_inode(handle, mpd->inode);
2311                 if (err)
2312                         /* This only happens if the journal is aborted */
2313                         return;
2314         }
2315
2316         /*
2317          * Update on-disk size along with block allocation.
2318          */
2319         disksize = ((loff_t) next + blks) << mpd->inode->i_blkbits;
2320         if (disksize > i_size_read(mpd->inode))
2321                 disksize = i_size_read(mpd->inode);
2322         if (disksize > EXT4_I(mpd->inode)->i_disksize) {
2323                 ext4_update_i_disksize(mpd->inode, disksize);
2324                 err = ext4_mark_inode_dirty(handle, mpd->inode);
2325                 if (err)
2326                         ext4_error(mpd->inode->i_sb,
2327                                    "Failed to mark inode %lu dirty",
2328                                    mpd->inode->i_ino);
2329         }
2330
2331 submit_io:
2332         mpage_da_submit_io(mpd, mapp);
2333         mpd->io_done = 1;
2334 }
2335
2336 #define BH_FLAGS ((1 << BH_Uptodate) | (1 << BH_Mapped) | \
2337                 (1 << BH_Delay) | (1 << BH_Unwritten))
2338
2339 /*
2340  * mpage_add_bh_to_extent - try to add one more block to extent of blocks
2341  *
2342  * @mpd->lbh - extent of blocks
2343  * @logical - logical number of the block in the file
2344  * @bh - bh of the block (used to access block's state)
2345  *
2346  * the function is used to collect contig. blocks in same state
2347  */
2348 static void mpage_add_bh_to_extent(struct mpage_da_data *mpd,
2349                                    sector_t logical, size_t b_size,
2350                                    unsigned long b_state)
2351 {
2352         sector_t next;
2353         int nrblocks = mpd->b_size >> mpd->inode->i_blkbits;
2354
2355         /*
2356          * XXX Don't go larger than mballoc is willing to allocate
2357          * This is a stopgap solution.  We eventually need to fold
2358          * mpage_da_submit_io() into this function and then call
2359          * ext4_map_blocks() multiple times in a loop
2360          */
2361         if (nrblocks >= 8*1024*1024/mpd->inode->i_sb->s_blocksize)
2362                 goto flush_it;
2363
2364         /* check if thereserved journal credits might overflow */
2365         if (!(ext4_test_inode_flag(mpd->inode, EXT4_INODE_EXTENTS))) {
2366                 if (nrblocks >= EXT4_MAX_TRANS_DATA) {
2367                         /*
2368                          * With non-extent format we are limited by the journal
2369                          * credit available.  Total credit needed to insert
2370                          * nrblocks contiguous blocks is dependent on the
2371                          * nrblocks.  So limit nrblocks.
2372                          */
2373                         goto flush_it;
2374                 } else if ((nrblocks + (b_size >> mpd->inode->i_blkbits)) >
2375                                 EXT4_MAX_TRANS_DATA) {
2376                         /*
2377                          * Adding the new buffer_head would make it cross the
2378                          * allowed limit for which we have journal credit
2379                          * reserved. So limit the new bh->b_size
2380                          */
2381                         b_size = (EXT4_MAX_TRANS_DATA - nrblocks) <<
2382                                                 mpd->inode->i_blkbits;
2383                         /* we will do mpage_da_submit_io in the next loop */
2384                 }
2385         }
2386         /*
2387          * First block in the extent
2388          */
2389         if (mpd->b_size == 0) {
2390                 mpd->b_blocknr = logical;
2391                 mpd->b_size = b_size;
2392                 mpd->b_state = b_state & BH_FLAGS;
2393                 return;
2394         }
2395
2396         next = mpd->b_blocknr + nrblocks;
2397         /*
2398          * Can we merge the block to our big extent?
2399          */
2400         if (logical == next && (b_state & BH_FLAGS) == mpd->b_state) {
2401                 mpd->b_size += b_size;
2402                 return;
2403         }
2404
2405 flush_it:
2406         /*
2407          * We couldn't merge the block to our extent, so we
2408          * need to flush current  extent and start new one
2409          */
2410         mpage_da_map_and_submit(mpd);
2411         return;
2412 }
2413
2414 static int ext4_bh_delay_or_unwritten(handle_t *handle, struct buffer_head *bh)
2415 {
2416         return (buffer_delay(bh) || buffer_unwritten(bh)) && buffer_dirty(bh);
2417 }
2418
2419 /*
2420  * __mpage_da_writepage - finds extent of pages and blocks
2421  *
2422  * @page: page to consider
2423  * @wbc: not used, we just follow rules
2424  * @data: context
2425  *
2426  * The function finds extents of pages and scan them for all blocks.
2427  */
2428 static int __mpage_da_writepage(struct page *page,
2429                                 struct writeback_control *wbc,
2430                                 struct mpage_da_data *mpd)
2431 {
2432         struct inode *inode = mpd->inode;
2433         struct buffer_head *bh, *head;
2434         sector_t logical;
2435
2436         /*
2437          * Can we merge this page to current extent?
2438          */
2439         if (mpd->next_page != page->index) {
2440                 /*
2441                  * Nope, we can't. So, we map non-allocated blocks
2442                  * and start IO on them
2443                  */
2444                 if (mpd->next_page != mpd->first_page) {
2445                         mpage_da_map_and_submit(mpd);
2446                         /*
2447                          * skip rest of the page in the page_vec
2448                          */
2449                         redirty_page_for_writepage(wbc, page);
2450                         unlock_page(page);
2451                         return MPAGE_DA_EXTENT_TAIL;
2452                 }
2453
2454                 /*
2455                  * Start next extent of pages ...
2456                  */
2457                 mpd->first_page = page->index;
2458
2459                 /*
2460                  * ... and blocks
2461                  */
2462                 mpd->b_size = 0;
2463                 mpd->b_state = 0;
2464                 mpd->b_blocknr = 0;
2465         }
2466
2467         mpd->next_page = page->index + 1;
2468         logical = (sector_t) page->index <<
2469                   (PAGE_CACHE_SHIFT - inode->i_blkbits);
2470
2471         if (!page_has_buffers(page)) {
2472                 mpage_add_bh_to_extent(mpd, logical, PAGE_CACHE_SIZE,
2473                                        (1 << BH_Dirty) | (1 << BH_Uptodate));
2474                 if (mpd->io_done)
2475                         return MPAGE_DA_EXTENT_TAIL;
2476         } else {
2477                 /*
2478                  * Page with regular buffer heads, just add all dirty ones
2479                  */
2480                 head = page_buffers(page);
2481                 bh = head;
2482                 do {
2483                         BUG_ON(buffer_locked(bh));
2484                         /*
2485                          * We need to try to allocate
2486                          * unmapped blocks in the same page.
2487                          * Otherwise we won't make progress
2488                          * with the page in ext4_writepage
2489                          */
2490                         if (ext4_bh_delay_or_unwritten(NULL, bh)) {
2491                                 mpage_add_bh_to_extent(mpd, logical,
2492                                                        bh->b_size,
2493                                                        bh->b_state);
2494                                 if (mpd->io_done)
2495                                         return MPAGE_DA_EXTENT_TAIL;
2496                         } else if (buffer_dirty(bh) && (buffer_mapped(bh))) {
2497                                 /*
2498                                  * mapped dirty buffer. We need to update
2499                                  * the b_state because we look at
2500                                  * b_state in mpage_da_map_blocks. We don't
2501                                  * update b_size because if we find an
2502                                  * unmapped buffer_head later we need to
2503                                  * use the b_state flag of that buffer_head.
2504                                  */
2505                                 if (mpd->b_size == 0)
2506                                         mpd->b_state = bh->b_state & BH_FLAGS;
2507                         }
2508                         logical++;
2509                 } while ((bh = bh->b_this_page) != head);
2510         }
2511
2512         return 0;
2513 }
2514
2515 /*
2516  * This is a special get_blocks_t callback which is used by
2517  * ext4_da_write_begin().  It will either return mapped block or
2518  * reserve space for a single block.
2519  *
2520  * For delayed buffer_head we have BH_Mapped, BH_New, BH_Delay set.
2521  * We also have b_blocknr = -1 and b_bdev initialized properly
2522  *
2523  * For unwritten buffer_head we have BH_Mapped, BH_New, BH_Unwritten set.
2524  * We also have b_blocknr = physicalblock mapping unwritten extent and b_bdev
2525  * initialized properly.
2526  */
2527 static int ext4_da_get_block_prep(struct inode *inode, sector_t iblock,
2528                                   struct buffer_head *bh, int create)
2529 {
2530         struct ext4_map_blocks map;
2531         int ret = 0;
2532         sector_t invalid_block = ~((sector_t) 0xffff);
2533
2534         if (invalid_block < ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es))
2535                 invalid_block = ~0;
2536
2537         BUG_ON(create == 0);
2538         BUG_ON(bh->b_size != inode->i_sb->s_blocksize);
2539
2540         map.m_lblk = iblock;
2541         map.m_len = 1;
2542
2543         /*
2544          * first, we need to know whether the block is allocated already
2545          * preallocated blocks are unmapped but should treated
2546          * the same as allocated blocks.
2547          */
2548         ret = ext4_map_blocks(NULL, inode, &map, 0);
2549         if (ret < 0)
2550                 return ret;
2551         if (ret == 0) {
2552                 if (buffer_delay(bh))
2553                         return 0; /* Not sure this could or should happen */
2554                 /*
2555                  * XXX: __block_write_begin() unmaps passed block, is it OK?
2556                  */
2557                 ret = ext4_da_reserve_space(inode, iblock);
2558                 if (ret)
2559                         /* not enough space to reserve */
2560                         return ret;
2561
2562                 map_bh(bh, inode->i_sb, invalid_block);
2563                 set_buffer_new(bh);
2564                 set_buffer_delay(bh);
2565                 return 0;
2566         }
2567
2568         map_bh(bh, inode->i_sb, map.m_pblk);
2569         bh->b_state = (bh->b_state & ~EXT4_MAP_FLAGS) | map.m_flags;
2570
2571         if (buffer_unwritten(bh)) {
2572                 /* A delayed write to unwritten bh should be marked
2573                  * new and mapped.  Mapped ensures that we don't do
2574                  * get_block multiple times when we write to the same
2575                  * offset and new ensures that we do proper zero out
2576                  * for partial write.
2577                  */
2578                 set_buffer_new(bh);
2579                 set_buffer_mapped(bh);
2580         }
2581         return 0;
2582 }
2583
2584 /*
2585  * This function is used as a standard get_block_t calback function
2586  * when there is no desire to allocate any blocks.  It is used as a
2587  * callback function for block_write_begin() and block_write_full_page().
2588  * These functions should only try to map a single block at a time.
2589  *
2590  * Since this function doesn't do block allocations even if the caller
2591  * requests it by passing in create=1, it is critically important that
2592  * any caller checks to make sure that any buffer heads are returned
2593  * by this function are either all already mapped or marked for
2594  * delayed allocation before calling  block_write_full_page().  Otherwise,
2595  * b_blocknr could be left unitialized, and the page write functions will
2596  * be taken by surprise.
2597  */
2598 static int noalloc_get_block_write(struct inode *inode, sector_t iblock,
2599                                    struct buffer_head *bh_result, int create)
2600 {
2601         BUG_ON(bh_result->b_size != inode->i_sb->s_blocksize);
2602         return _ext4_get_block(inode, iblock, bh_result, 0);
2603 }
2604
2605 static int bget_one(handle_t *handle, struct buffer_head *bh)
2606 {
2607         get_bh(bh);
2608         return 0;
2609 }
2610
2611 static int bput_one(handle_t *handle, struct buffer_head *bh)
2612 {
2613         put_bh(bh);
2614         return 0;
2615 }
2616
2617 static int __ext4_journalled_writepage(struct page *page,
2618                                        unsigned int len)
2619 {
2620         struct address_space *mapping = page->mapping;
2621         struct inode *inode = mapping->host;
2622         struct buffer_head *page_bufs;
2623         handle_t *handle = NULL;
2624         int ret = 0;
2625         int err;
2626
2627         ClearPageChecked(page);
2628         page_bufs = page_buffers(page);
2629         BUG_ON(!page_bufs);
2630         walk_page_buffers(handle, page_bufs, 0, len, NULL, bget_one);
2631         /* As soon as we unlock the page, it can go away, but we have
2632          * references to buffers so we are safe */
2633         unlock_page(page);
2634
2635         handle = ext4_journal_start(inode, ext4_writepage_trans_blocks(inode));
2636         if (IS_ERR(handle)) {
2637                 ret = PTR_ERR(handle);
2638                 goto out;
2639         }
2640
2641         ret = walk_page_buffers(handle, page_bufs, 0, len, NULL,
2642                                 do_journal_get_write_access);
2643
2644         err = walk_page_buffers(handle, page_bufs, 0, len, NULL,
2645                                 write_end_fn);
2646         if (ret == 0)
2647                 ret = err;
2648         err = ext4_journal_stop(handle);
2649         if (!ret)
2650                 ret = err;
2651
2652         walk_page_buffers(handle, page_bufs, 0, len, NULL, bput_one);
2653         ext4_set_inode_state(inode, EXT4_STATE_JDATA);
2654 out:
2655         return ret;
2656 }
2657
2658 static int ext4_set_bh_endio(struct buffer_head *bh, struct inode *inode);
2659 static void ext4_end_io_buffer_write(struct buffer_head *bh, int uptodate);
2660
2661 /*
2662  * Note that we don't need to start a transaction unless we're journaling data
2663  * because we should have holes filled from ext4_page_mkwrite(). We even don't
2664  * need to file the inode to the transaction's list in ordered mode because if
2665  * we are writing back data added by write(), the inode is already there and if
2666  * we are writing back data modified via mmap(), noone guarantees in which
2667  * transaction the data will hit the disk. In case we are journaling data, we
2668  * cannot start transaction directly because transaction start ranks above page
2669  * lock so we have to do some magic.
2670  *
2671  * This function can get called via...
2672  *   - ext4_da_writepages after taking page lock (have journal handle)
2673  *   - journal_submit_inode_data_buffers (no journal handle)
2674  *   - shrink_page_list via pdflush (no journal handle)
2675  *   - grab_page_cache when doing write_begin (have journal handle)
2676  *
2677  * We don't do any block allocation in this function. If we have page with
2678  * multiple blocks we need to write those buffer_heads that are mapped. This
2679  * is important for mmaped based write. So if we do with blocksize 1K
2680  * truncate(f, 1024);
2681  * a = mmap(f, 0, 4096);
2682  * a[0] = 'a';
2683  * truncate(f, 4096);
2684  * we have in the page first buffer_head mapped via page_mkwrite call back
2685  * but other bufer_heads would be unmapped but dirty(dirty done via the
2686  * do_wp_page). So writepage should write the first block. If we modify
2687  * the mmap area beyond 1024 we will again get a page_fault and the
2688  * page_mkwrite callback will do the block allocation and mark the
2689  * buffer_heads mapped.
2690  *
2691  * We redirty the page if we have any buffer_heads that is either delay or
2692  * unwritten in the page.
2693  *
2694  * We can get recursively called as show below.
2695  *
2696  *      ext4_writepage() -> kmalloc() -> __alloc_pages() -> page_launder() ->
2697  *              ext4_writepage()
2698  *
2699  * But since we don't do any block allocation we should not deadlock.
2700  * Page also have the dirty flag cleared so we don't get recurive page_lock.
2701  */
2702 static int ext4_writepage(struct page *page,
2703                           struct writeback_control *wbc)
2704 {
2705         int ret = 0, commit_write = 0;
2706         loff_t size;
2707         unsigned int len;
2708         struct buffer_head *page_bufs = NULL;
2709         struct inode *inode = page->mapping->host;
2710
2711         trace_ext4_writepage(inode, page);
2712         size = i_size_read(inode);
2713         if (page->index == size >> PAGE_CACHE_SHIFT)
2714                 len = size & ~PAGE_CACHE_MASK;
2715         else
2716                 len = PAGE_CACHE_SIZE;
2717
2718         /*
2719          * If the page does not have buffers (for whatever reason),
2720          * try to create them using __block_write_begin.  If this
2721          * fails, redirty the page and move on.
2722          */
2723         if (!page_has_buffers(page)) {
2724                 if (__block_write_begin(page, 0, len,
2725                                         noalloc_get_block_write)) {
2726                 redirty_page:
2727                         redirty_page_for_writepage(wbc, page);
2728                         unlock_page(page);
2729                         return 0;
2730                 }
2731                 commit_write = 1;
2732         }
2733         page_bufs = page_buffers(page);
2734         if (walk_page_buffers(NULL, page_bufs, 0, len, NULL,
2735                               ext4_bh_delay_or_unwritten)) {
2736                 /*
2737                  * We don't want to do block allocation, so redirty
2738                  * the page and return.  We may reach here when we do
2739                  * a journal commit via journal_submit_inode_data_buffers.
2740                  * We can also reach here via shrink_page_list
2741                  */
2742                 goto redirty_page;
2743         }
2744         if (commit_write)
2745                 /* now mark the buffer_heads as dirty and uptodate */
2746                 block_commit_write(page, 0, len);
2747
2748         if (PageChecked(page) && ext4_should_journal_data(inode))
2749                 /*
2750                  * It's mmapped pagecache.  Add buffers and journal it.  There
2751                  * doesn't seem much point in redirtying the page here.
2752                  */
2753                 return __ext4_journalled_writepage(page, len);
2754
2755         if (buffer_uninit(page_bufs)) {
2756                 ext4_set_bh_endio(page_bufs, inode);
2757                 ret = block_write_full_page_endio(page, noalloc_get_block_write,
2758                                             wbc, ext4_end_io_buffer_write);
2759         } else
2760                 ret = block_write_full_page(page, noalloc_get_block_write,
2761                                             wbc);
2762
2763         return ret;
2764 }
2765
2766 /*
2767  * This is called via ext4_da_writepages() to
2768  * calulate the total number of credits to reserve to fit
2769  * a single extent allocation into a single transaction,
2770  * ext4_da_writpeages() will loop calling this before
2771  * the block allocation.
2772  */
2773
2774 static int ext4_da_writepages_trans_blocks(struct inode *inode)
2775 {
2776         int max_blocks = EXT4_I(inode)->i_reserved_data_blocks;
2777
2778         /*
2779          * With non-extent format the journal credit needed to
2780          * insert nrblocks contiguous block is dependent on
2781          * number of contiguous block. So we will limit
2782          * number of contiguous block to a sane value
2783          */
2784         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) &&
2785             (max_blocks > EXT4_MAX_TRANS_DATA))
2786                 max_blocks = EXT4_MAX_TRANS_DATA;
2787
2788         return ext4_chunk_trans_blocks(inode, max_blocks);
2789 }
2790
2791 /*
2792  * write_cache_pages_da - walk the list of dirty pages of the given
2793  * address space and call the callback function (which usually writes
2794  * the pages).
2795  *
2796  * This is a forked version of write_cache_pages().  Differences:
2797  *      Range cyclic is ignored.
2798  *      no_nrwrite_index_update is always presumed true
2799  */
2800 static int write_cache_pages_da(struct address_space *mapping,
2801                                 struct writeback_control *wbc,
2802                                 struct mpage_da_data *mpd,
2803                                 pgoff_t *done_index)
2804 {
2805         int ret = 0;
2806         int done = 0;
2807         struct pagevec pvec;
2808         unsigned nr_pages;
2809         pgoff_t index;
2810         pgoff_t end;            /* Inclusive */
2811         long nr_to_write = wbc->nr_to_write;
2812         int tag;
2813
2814         pagevec_init(&pvec, 0);
2815         index = wbc->range_start >> PAGE_CACHE_SHIFT;
2816         end = wbc->range_end >> PAGE_CACHE_SHIFT;
2817
2818         if (wbc->sync_mode == WB_SYNC_ALL)
2819                 tag = PAGECACHE_TAG_TOWRITE;
2820         else
2821                 tag = PAGECACHE_TAG_DIRTY;
2822
2823         *done_index = index;
2824         while (!done && (index <= end)) {
2825                 int i;
2826
2827                 nr_pages = pagevec_lookup_tag(&pvec, mapping, &index, tag,
2828                               min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1);
2829                 if (nr_pages == 0)
2830                         break;
2831
2832                 for (i = 0; i < nr_pages; i++) {
2833                         struct page *page = pvec.pages[i];
2834
2835                         /*
2836                          * At this point, the page may be truncated or
2837                          * invalidated (changing page->mapping to NULL), or
2838                          * even swizzled back from swapper_space to tmpfs file
2839                          * mapping. However, page->index will not change
2840                          * because we have a reference on the page.
2841                          */
2842                         if (page->index > end) {
2843                                 done = 1;
2844                                 break;
2845                         }
2846
2847                         *done_index = page->index + 1;
2848
2849                         lock_page(page);
2850
2851                         /*
2852                          * Page truncated or invalidated. We can freely skip it
2853                          * then, even for data integrity operations: the page
2854                          * has disappeared concurrently, so there could be no
2855                          * real expectation of this data interity operation
2856                          * even if there is now a new, dirty page at the same
2857                          * pagecache address.
2858                          */
2859                         if (unlikely(page->mapping != mapping)) {
2860 continue_unlock:
2861                                 unlock_page(page);
2862                                 continue;
2863                         }
2864
2865                         if (!PageDirty(page)) {
2866                                 /* someone wrote it for us */
2867                                 goto continue_unlock;
2868                         }
2869
2870                         if (PageWriteback(page)) {
2871                                 if (wbc->sync_mode != WB_SYNC_NONE)
2872                                         wait_on_page_writeback(page);
2873                                 else
2874                                         goto continue_unlock;
2875                         }
2876
2877                         BUG_ON(PageWriteback(page));
2878                         if (!clear_page_dirty_for_io(page))
2879                                 goto continue_unlock;
2880
2881                         ret = __mpage_da_writepage(page, wbc, mpd);
2882                         if (unlikely(ret)) {
2883                                 if (ret == AOP_WRITEPAGE_ACTIVATE) {
2884                                         unlock_page(page);
2885                                         ret = 0;
2886                                 } else {
2887                                         done = 1;
2888                                         break;
2889                                 }
2890                         }
2891
2892                         if (nr_to_write > 0) {
2893                                 nr_to_write--;
2894                                 if (nr_to_write == 0 &&
2895                                     wbc->sync_mode == WB_SYNC_NONE) {
2896                                         /*
2897                                          * We stop writing back only if we are
2898                                          * not doing integrity sync. In case of
2899                                          * integrity sync we have to keep going
2900                                          * because someone may be concurrently
2901                                          * dirtying pages, and we might have
2902                                          * synced a lot of newly appeared dirty
2903                                          * pages, but have not synced all of the
2904                                          * old dirty pages.
2905                                          */
2906                                         done = 1;
2907                                         break;
2908                                 }
2909                         }
2910                 }
2911                 pagevec_release(&pvec);
2912                 cond_resched();
2913         }
2914         return ret;
2915 }
2916
2917
2918 static int ext4_da_writepages(struct address_space *mapping,
2919                               struct writeback_control *wbc)
2920 {
2921         pgoff_t index;
2922         int range_whole = 0;
2923         handle_t *handle = NULL;
2924         struct mpage_da_data mpd;
2925         struct inode *inode = mapping->host;
2926         int pages_written = 0;
2927         long pages_skipped;
2928         unsigned int max_pages;
2929         int range_cyclic, cycled = 1, io_done = 0;
2930         int needed_blocks, ret = 0;
2931         long desired_nr_to_write, nr_to_writebump = 0;
2932         loff_t range_start = wbc->range_start;
2933         struct ext4_sb_info *sbi = EXT4_SB(mapping->host->i_sb);
2934         pgoff_t done_index = 0;
2935         pgoff_t end;
2936
2937         trace_ext4_da_writepages(inode, wbc);
2938
2939         /*
2940          * No pages to write? This is mainly a kludge to avoid starting
2941          * a transaction for special inodes like journal inode on last iput()
2942          * because that could violate lock ordering on umount
2943          */
2944         if (!mapping->nrpages || !mapping_tagged(mapping, PAGECACHE_TAG_DIRTY))
2945                 return 0;
2946
2947         /*
2948          * If the filesystem has aborted, it is read-only, so return
2949          * right away instead of dumping stack traces later on that
2950          * will obscure the real source of the problem.  We test
2951          * EXT4_MF_FS_ABORTED instead of sb->s_flag's MS_RDONLY because
2952          * the latter could be true if the filesystem is mounted
2953          * read-only, and in that case, ext4_da_writepages should
2954          * *never* be called, so if that ever happens, we would want
2955          * the stack trace.
2956          */
2957         if (unlikely(sbi->s_mount_flags & EXT4_MF_FS_ABORTED))
2958                 return -EROFS;
2959
2960         if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
2961                 range_whole = 1;
2962
2963         range_cyclic = wbc->range_cyclic;
2964         if (wbc->range_cyclic) {
2965                 index = mapping->writeback_index;
2966                 if (index)
2967                         cycled = 0;
2968                 wbc->range_start = index << PAGE_CACHE_SHIFT;
2969                 wbc->range_end  = LLONG_MAX;
2970                 wbc->range_cyclic = 0;
2971                 end = -1;
2972         } else {
2973                 index = wbc->range_start >> PAGE_CACHE_SHIFT;
2974                 end = wbc->range_end >> PAGE_CACHE_SHIFT;
2975         }
2976
2977         /*
2978          * This works around two forms of stupidity.  The first is in
2979          * the writeback code, which caps the maximum number of pages
2980          * written to be 1024 pages.  This is wrong on multiple
2981          * levels; different architectues have a different page size,
2982          * which changes the maximum amount of data which gets
2983          * written.  Secondly, 4 megabytes is way too small.  XFS
2984          * forces this value to be 16 megabytes by multiplying
2985          * nr_to_write parameter by four, and then relies on its
2986          * allocator to allocate larger extents to make them
2987          * contiguous.  Unfortunately this brings us to the second
2988          * stupidity, which is that ext4's mballoc code only allocates
2989          * at most 2048 blocks.  So we force contiguous writes up to
2990          * the number of dirty blocks in the inode, or
2991          * sbi->max_writeback_mb_bump whichever is smaller.
2992          */
2993         max_pages = sbi->s_max_writeback_mb_bump << (20 - PAGE_CACHE_SHIFT);
2994         if (!range_cyclic && range_whole) {
2995                 if (wbc->nr_to_write == LONG_MAX)
2996                         desired_nr_to_write = wbc->nr_to_write;
2997                 else
2998                         desired_nr_to_write = wbc->nr_to_write * 8;
2999         } else
3000                 desired_nr_to_write = ext4_num_dirty_pages(inode, index,
3001                                                            max_pages);
3002         if (desired_nr_to_write > max_pages)
3003                 desired_nr_to_write = max_pages;
3004
3005         if (wbc->nr_to_write < desired_nr_to_write) {
3006                 nr_to_writebump = desired_nr_to_write - wbc->nr_to_write;
3007                 wbc->nr_to_write = desired_nr_to_write;
3008         }
3009
3010         mpd.wbc = wbc;
3011         mpd.inode = mapping->host;
3012
3013         pages_skipped = wbc->pages_skipped;
3014
3015 retry:
3016         if (wbc->sync_mode == WB_SYNC_ALL)
3017                 tag_pages_for_writeback(mapping, index, end);
3018
3019         while (!ret && wbc->nr_to_write > 0) {
3020
3021                 /*
3022                  * we  insert one extent at a time. So we need
3023                  * credit needed for single extent allocation.
3024                  * journalled mode is currently not supported
3025                  * by delalloc
3026                  */
3027                 BUG_ON(ext4_should_journal_data(inode));
3028                 needed_blocks = ext4_da_writepages_trans_blocks(inode);
3029
3030                 /* start a new transaction*/
3031                 handle = ext4_journal_start(inode, needed_blocks);
3032                 if (IS_ERR(handle)) {
3033                         ret = PTR_ERR(handle);
3034                         ext4_msg(inode->i_sb, KERN_CRIT, "%s: jbd2_start: "
3035                                "%ld pages, ino %lu; err %d", __func__,
3036                                 wbc->nr_to_write, inode->i_ino, ret);
3037                         goto out_writepages;
3038                 }
3039
3040                 /*
3041                  * Now call __mpage_da_writepage to find the next
3042                  * contiguous region of logical blocks that need
3043                  * blocks to be allocated by ext4.  We don't actually
3044                  * submit the blocks for I/O here, even though
3045                  * write_cache_pages thinks it will, and will set the
3046                  * pages as clean for write before calling
3047                  * __mpage_da_writepage().
3048                  */
3049                 mpd.b_size = 0;
3050                 mpd.b_state = 0;
3051                 mpd.b_blocknr = 0;
3052                 mpd.first_page = 0;
3053                 mpd.next_page = 0;
3054                 mpd.io_done = 0;
3055                 mpd.pages_written = 0;
3056                 mpd.retval = 0;
3057                 ret = write_cache_pages_da(mapping, wbc, &mpd, &done_index);
3058                 /*
3059                  * If we have a contiguous extent of pages and we
3060                  * haven't done the I/O yet, map the blocks and submit
3061                  * them for I/O.
3062                  */
3063                 if (!mpd.io_done && mpd.next_page != mpd.first_page) {
3064                         mpage_da_map_and_submit(&mpd);
3065                         ret = MPAGE_DA_EXTENT_TAIL;
3066                 }
3067                 trace_ext4_da_write_pages(inode, &mpd);
3068                 wbc->nr_to_write -= mpd.pages_written;
3069
3070                 ext4_journal_stop(handle);
3071
3072                 if ((mpd.retval == -ENOSPC) && sbi->s_journal) {
3073                         /* commit the transaction which would
3074                          * free blocks released in the transaction
3075                          * and try again
3076                          */
3077                         jbd2_journal_force_commit_nested(sbi->s_journal);
3078                         wbc->pages_skipped = pages_skipped;
3079                         ret = 0;
3080                 } else if (ret == MPAGE_DA_EXTENT_TAIL) {
3081                         /*
3082                          * got one extent now try with
3083                          * rest of the pages
3084                          */
3085                         pages_written += mpd.pages_written;
3086                         wbc->pages_skipped = pages_skipped;
3087                         ret = 0;
3088                         io_done = 1;
3089                 } else if (wbc->nr_to_write)
3090                         /*
3091                          * There is no more writeout needed
3092                          * or we requested for a noblocking writeout
3093                          * and we found the device congested
3094                          */
3095                         break;
3096         }
3097         if (!io_done && !cycled) {
3098                 cycled = 1;
3099                 index = 0;
3100                 wbc->range_start = index << PAGE_CACHE_SHIFT;
3101                 wbc->range_end  = mapping->writeback_index - 1;
3102                 goto retry;
3103         }
3104         if (pages_skipped != wbc->pages_skipped)
3105                 ext4_msg(inode->i_sb, KERN_CRIT,
3106                          "This should not happen leaving %s "
3107                          "with nr_to_write = %ld ret = %d",
3108                          __func__, wbc->nr_to_write, ret);
3109
3110         /* Update index */
3111         wbc->range_cyclic = range_cyclic;
3112         if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
3113                 /*
3114                  * set the writeback_index so that range_cyclic
3115                  * mode will write it back later
3116                  */
3117                 mapping->writeback_index = done_index;
3118
3119 out_writepages:
3120         wbc->nr_to_write -= nr_to_writebump;
3121         wbc->range_start = range_start;
3122         trace_ext4_da_writepages_result(inode, wbc, ret, pages_written);
3123         return ret;
3124 }
3125
3126 #define FALL_BACK_TO_NONDELALLOC 1
3127 static int ext4_nonda_switch(struct super_block *sb)
3128 {
3129         s64 free_blocks, dirty_blocks;
3130         struct ext4_sb_info *sbi = EXT4_SB(sb);
3131
3132         /*
3133          * switch to non delalloc mode if we are running low
3134          * on free block. The free block accounting via percpu
3135          * counters can get slightly wrong with percpu_counter_batch getting
3136          * accumulated on each CPU without updating global counters
3137          * Delalloc need an accurate free block accounting. So switch
3138          * to non delalloc when we are near to error range.
3139          */
3140         free_blocks  = percpu_counter_read_positive(&sbi->s_freeblocks_counter);
3141         dirty_blocks = percpu_counter_read_positive(&sbi->s_dirtyblocks_counter);
3142         if (2 * free_blocks < 3 * dirty_blocks ||
3143                 free_blocks < (dirty_blocks + EXT4_FREEBLOCKS_WATERMARK)) {
3144                 /*
3145                  * free block count is less than 150% of dirty blocks
3146                  * or free blocks is less than watermark
3147                  */
3148                 return 1;
3149         }
3150         /*
3151          * Even if we don't switch but are nearing capacity,
3152          * start pushing delalloc when 1/2 of free blocks are dirty.
3153          */
3154         if (free_blocks < 2 * dirty_blocks)
3155                 writeback_inodes_sb_if_idle(sb);
3156
3157         return 0;
3158 }
3159
3160 static int ext4_da_write_begin(struct file *file, struct address_space *mapping,
3161                                loff_t pos, unsigned len, unsigned flags,
3162                                struct page **pagep, void **fsdata)
3163 {
3164         int ret, retries = 0;
3165         struct page *page;
3166         pgoff_t index;
3167         struct inode *inode = mapping->host;
3168         handle_t *handle;
3169
3170         index = pos >> PAGE_CACHE_SHIFT;
3171
3172         if (ext4_nonda_switch(inode->i_sb)) {
3173                 *fsdata = (void *)FALL_BACK_TO_NONDELALLOC;
3174                 return ext4_write_begin(file, mapping, pos,
3175                                         len, flags, pagep, fsdata);
3176         }
3177         *fsdata = (void *)0;
3178         trace_ext4_da_write_begin(inode, pos, len, flags);
3179 retry:
3180         /*
3181          * With delayed allocation, we don't log the i_disksize update
3182          * if there is delayed block allocation. But we still need
3183          * to journalling the i_disksize update if writes to the end
3184          * of file which has an already mapped buffer.
3185          */
3186         handle = ext4_journal_start(inode, 1);
3187         if (IS_ERR(handle)) {
3188                 ret = PTR_ERR(handle);
3189                 goto out;
3190         }
3191         /* We cannot recurse into the filesystem as the transaction is already
3192          * started */
3193         flags |= AOP_FLAG_NOFS;
3194
3195         page = grab_cache_page_write_begin(mapping, index, flags);
3196         if (!page) {
3197                 ext4_journal_stop(handle);
3198                 ret = -ENOMEM;
3199                 goto out;
3200         }
3201         *pagep = page;
3202
3203         ret = __block_write_begin(page, pos, len, ext4_da_get_block_prep);
3204         if (ret < 0) {
3205                 unlock_page(page);
3206                 ext4_journal_stop(handle);
3207                 page_cache_release(page);
3208                 /*
3209                  * block_write_begin may have instantiated a few blocks
3210                  * outside i_size.  Trim these off again. Don't need
3211                  * i_size_read because we hold i_mutex.
3212                  */
3213                 if (pos + len > inode->i_size)
3214                         ext4_truncate_failed_write(inode);
3215         }
3216
3217         if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
3218                 goto retry;
3219 out:
3220         return ret;
3221 }
3222
3223 /*
3224  * Check if we should update i_disksize
3225  * when write to the end of file but not require block allocation
3226  */
3227 static int ext4_da_should_update_i_disksize(struct page *page,
3228                                             unsigned long offset)
3229 {
3230         struct buffer_head *bh;
3231         struct inode *inode = page->mapping->host;
3232         unsigned int idx;
3233         int i;
3234
3235         bh = page_buffers(page);
3236         idx = offset >> inode->i_blkbits;
3237
3238         for (i = 0; i < idx; i++)
3239                 bh = bh->b_this_page;
3240
3241         if (!buffer_mapped(bh) || (buffer_delay(bh)) || buffer_unwritten(bh))
3242                 return 0;
3243         return 1;
3244 }
3245
3246 static int ext4_da_write_end(struct file *file,
3247                              struct address_space *mapping,
3248                              loff_t pos, unsigned len, unsigned copied,
3249                              struct page *page, void *fsdata)
3250 {
3251         struct inode *inode = mapping->host;
3252         int ret = 0, ret2;
3253         handle_t *handle = ext4_journal_current_handle();
3254         loff_t new_i_size;
3255         unsigned long start, end;
3256         int write_mode = (int)(unsigned long)fsdata;
3257
3258         if (write_mode == FALL_BACK_TO_NONDELALLOC) {
3259                 if (ext4_should_order_data(inode)) {
3260                         return ext4_ordered_write_end(file, mapping, pos,
3261                                         len, copied, page, fsdata);
3262                 } else if (ext4_should_writeback_data(inode)) {
3263                         return ext4_writeback_write_end(file, mapping, pos,
3264                                         len, copied, page, fsdata);
3265                 } else {
3266                         BUG();
3267                 }
3268         }
3269
3270         trace_ext4_da_write_end(inode, pos, len, copied);
3271         start = pos & (PAGE_CACHE_SIZE - 1);
3272         end = start + copied - 1;
3273
3274         /*
3275          * generic_write_end() will run mark_inode_dirty() if i_size
3276          * changes.  So let's piggyback the i_disksize mark_inode_dirty
3277          * into that.
3278          */
3279
3280         new_i_size = pos + copied;
3281         if (new_i_size > EXT4_I(inode)->i_disksize) {
3282                 if (ext4_da_should_update_i_disksize(page, end)) {
3283                         down_write(&EXT4_I(inode)->i_data_sem);
3284                         if (new_i_size > EXT4_I(inode)->i_disksize) {
3285                                 /*
3286                                  * Updating i_disksize when extending file
3287                                  * without needing block allocation
3288                                  */
3289                                 if (ext4_should_order_data(inode))
3290                                         ret = ext4_jbd2_file_inode(handle,
3291                                                                    inode);
3292
3293                                 EXT4_I(inode)->i_disksize = new_i_size;
3294                         }
3295                         up_write(&EXT4_I(inode)->i_data_sem);
3296                         /* We need to mark inode dirty even if
3297                          * new_i_size is less that inode->i_size
3298                          * bu greater than i_disksize.(hint delalloc)
3299                          */
3300                         ext4_mark_inode_dirty(handle, inode);
3301                 }
3302         }
3303         ret2 = generic_write_end(file, mapping, pos, len, copied,
3304                                                         page, fsdata);
3305         copied = ret2;
3306         if (ret2 < 0)
3307                 ret = ret2;
3308         ret2 = ext4_journal_stop(handle);
3309         if (!ret)
3310                 ret = ret2;
3311
3312         return ret ? ret : copied;
3313 }
3314
3315 static void ext4_da_invalidatepage(struct page *page, unsigned long offset)
3316 {
3317         /*
3318          * Drop reserved blocks
3319          */
3320         BUG_ON(!PageLocked(page));
3321         if (!page_has_buffers(page))
3322                 goto out;
3323
3324         ext4_da_page_release_reservation(page, offset);
3325
3326 out:
3327         ext4_invalidatepage(page, offset);
3328
3329         return;
3330 }
3331
3332 /*
3333  * Force all delayed allocation blocks to be allocated for a given inode.
3334  */
3335 int ext4_alloc_da_blocks(struct inode *inode)
3336 {
3337         trace_ext4_alloc_da_blocks(inode);
3338
3339         if (!EXT4_I(inode)->i_reserved_data_blocks &&
3340             !EXT4_I(inode)->i_reserved_meta_blocks)
3341                 return 0;
3342
3343         /*
3344          * We do something simple for now.  The filemap_flush() will
3345          * also start triggering a write of the data blocks, which is
3346          * not strictly speaking necessary (and for users of
3347          * laptop_mode, not even desirable).  However, to do otherwise
3348          * would require replicating code paths in:
3349          *
3350          * ext4_da_writepages() ->
3351          *    write_cache_pages() ---> (via passed in callback function)
3352          *        __mpage_da_writepage() -->
3353          *           mpage_add_bh_to_extent()
3354          *           mpage_da_map_blocks()
3355          *
3356          * The problem is that write_cache_pages(), located in
3357          * mm/page-writeback.c, marks pages clean in preparation for
3358          * doing I/O, which is not desirable if we're not planning on
3359          * doing I/O at all.
3360          *
3361          * We could call write_cache_pages(), and then redirty all of
3362          * the pages by calling redirty_page_for_writeback() but that
3363          * would be ugly in the extreme.  So instead we would need to
3364          * replicate parts of the code in the above functions,
3365          * simplifying them becuase we wouldn't actually intend to
3366          * write out the pages, but rather only collect contiguous
3367          * logical block extents, call the multi-block allocator, and
3368          * then update the buffer heads with the block allocations.
3369          *
3370          * For now, though, we'll cheat by calling filemap_flush(),
3371          * which will map the blocks, and start the I/O, but not
3372          * actually wait for the I/O to complete.
3373          */
3374         return filemap_flush(inode->i_mapping);
3375 }
3376
3377 /*
3378  * bmap() is special.  It gets used by applications such as lilo and by
3379  * the swapper to find the on-disk block of a specific piece of data.
3380  *
3381  * Naturally, this is dangerous if the block concerned is still in the
3382  * journal.  If somebody makes a swapfile on an ext4 data-journaling
3383  * filesystem and enables swap, then they may get a nasty shock when the
3384  * data getting swapped to that swapfile suddenly gets overwritten by
3385  * the original zero's written out previously to the journal and
3386  * awaiting writeback in the kernel's buffer cache.
3387  *
3388  * So, if we see any bmap calls here on a modified, data-journaled file,
3389  * take extra steps to flush any blocks which might be in the cache.
3390  */
3391 static sector_t ext4_bmap(struct address_space *mapping, sector_t block)
3392 {
3393         struct inode *inode = mapping->host;
3394         journal_t *journal;
3395         int err;
3396
3397         if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY) &&
3398                         test_opt(inode->i_sb, DELALLOC)) {
3399                 /*
3400                  * With delalloc we want to sync the file
3401                  * so that we can make sure we allocate
3402                  * blocks for file
3403                  */
3404                 filemap_write_and_wait(mapping);
3405         }
3406
3407         if (EXT4_JOURNAL(inode) &&
3408             ext4_test_inode_state(inode, EXT4_STATE_JDATA)) {
3409                 /*
3410                  * This is a REALLY heavyweight approach, but the use of
3411                  * bmap on dirty files is expected to be extremely rare:
3412                  * only if we run lilo or swapon on a freshly made file
3413                  * do we expect this to happen.
3414                  *
3415                  * (bmap requires CAP_SYS_RAWIO so this does not
3416                  * represent an unprivileged user DOS attack --- we'd be
3417                  * in trouble if mortal users could trigger this path at
3418                  * will.)
3419                  *
3420                  * NB. EXT4_STATE_JDATA is not set on files other than
3421                  * regular files.  If somebody wants to bmap a directory
3422                  * or symlink and gets confused because the buffer
3423                  * hasn't yet been flushed to disk, they deserve
3424                  * everything they get.
3425                  */
3426
3427                 ext4_clear_inode_state(inode, EXT4_STATE_JDATA);
3428                 journal = EXT4_JOURNAL(inode);
3429                 jbd2_journal_lock_updates(journal);
3430                 err = jbd2_journal_flush(journal);
3431                 jbd2_journal_unlock_updates(journal);
3432
3433                 if (err)
3434                         return 0;
3435         }
3436
3437         return generic_block_bmap(mapping, block, ext4_get_block);
3438 }
3439
3440 static int ext4_readpage(struct file *file, struct page *page)
3441 {
3442         return mpage_readpage(page, ext4_get_block);
3443 }
3444
3445 static int
3446 ext4_readpages(struct file *file, struct address_space *mapping,
3447                 struct list_head *pages, unsigned nr_pages)
3448 {
3449         return mpage_readpages(mapping, pages, nr_pages, ext4_get_block);
3450 }
3451
3452 static void ext4_invalidatepage_free_endio(struct page *page, unsigned long offset)
3453 {
3454         struct buffer_head *head, *bh;
3455         unsigned int curr_off = 0;
3456
3457         if (!page_has_buffers(page))
3458                 return;
3459         head = bh = page_buffers(page);
3460         do {
3461                 if (offset <= curr_off && test_clear_buffer_uninit(bh)
3462                                         && bh->b_private) {
3463                         ext4_free_io_end(bh->b_private);
3464                         bh->b_private = NULL;
3465                         bh->b_end_io = NULL;
3466                 }
3467                 curr_off = curr_off + bh->b_size;
3468                 bh = bh->b_this_page;
3469         } while (bh != head);
3470 }
3471
3472 static void ext4_invalidatepage(struct page *page, unsigned long offset)
3473 {
3474         journal_t *journal = EXT4_JOURNAL(page->mapping->host);
3475
3476         /*
3477          * free any io_end structure allocated for buffers to be discarded
3478          */
3479         if (ext4_should_dioread_nolock(page->mapping->host))
3480                 ext4_invalidatepage_free_endio(page, offset);
3481         /*
3482          * If it's a full truncate we just forget about the pending dirtying
3483          */
3484         if (offset == 0)
3485                 ClearPageChecked(page);
3486
3487         if (journal)
3488                 jbd2_journal_invalidatepage(journal, page, offset);
3489         else
3490                 block_invalidatepage(page, offset);
3491 }
3492
3493 static int ext4_releasepage(struct page *page, gfp_t wait)
3494 {
3495         journal_t *journal = EXT4_JOURNAL(page->mapping->host);
3496
3497         WARN_ON(PageChecked(page));
3498         if (!page_has_buffers(page))
3499                 return 0;
3500         if (journal)
3501                 return jbd2_journal_try_to_free_buffers(journal, page, wait);
3502         else
3503                 return try_to_free_buffers(page);
3504 }
3505
3506 /*
3507  * O_DIRECT for ext3 (or indirect map) based files
3508  *
3509  * If the O_DIRECT write will extend the file then add this inode to the
3510  * orphan list.  So recovery will truncate it back to the original size
3511  * if the machine crashes during the write.
3512  *
3513  * If the O_DIRECT write is intantiating holes inside i_size and the machine
3514  * crashes then stale disk data _may_ be exposed inside the file. But current
3515  * VFS code falls back into buffered path in that case so we are safe.
3516  */
3517 static ssize_t ext4_ind_direct_IO(int rw, struct kiocb *iocb,
3518                               const struct iovec *iov, loff_t offset,
3519                               unsigned long nr_segs)
3520 {
3521         struct file *file = iocb->ki_filp;
3522         struct inode *inode = file->f_mapping->host;
3523         struct ext4_inode_info *ei = EXT4_I(inode);
3524         handle_t *handle;
3525         ssize_t ret;
3526         int orphan = 0;
3527         size_t count = iov_length(iov, nr_segs);
3528         int retries = 0;
3529
3530         if (rw == WRITE) {
3531                 loff_t final_size = offset + count;
3532
3533                 if (final_size > inode->i_size) {
3534                         /* Credits for sb + inode write */
3535                         handle = ext4_journal_start(inode, 2);
3536                         if (IS_ERR(handle)) {
3537                                 ret = PTR_ERR(handle);
3538                                 goto out;
3539                         }
3540                         ret = ext4_orphan_add(handle, inode);
3541                         if (ret) {
3542                                 ext4_journal_stop(handle);
3543                                 goto out;
3544                         }
3545                         orphan = 1;
3546                         ei->i_disksize = inode->i_size;
3547                         ext4_journal_stop(handle);
3548                 }
3549         }
3550
3551 retry:
3552         if (rw == READ && ext4_should_dioread_nolock(inode))
3553                 ret = __blockdev_direct_IO(rw, iocb, inode,
3554                                  inode->i_sb->s_bdev, iov,
3555                                  offset, nr_segs,
3556                                  ext4_get_block, NULL, NULL, 0);
3557         else {
3558                 ret = blockdev_direct_IO(rw, iocb, inode,
3559                                  inode->i_sb->s_bdev, iov,
3560                                  offset, nr_segs,
3561                                  ext4_get_block, NULL);
3562
3563                 if (unlikely((rw & WRITE) && ret < 0)) {
3564                         loff_t isize = i_size_read(inode);
3565                         loff_t end = offset + iov_length(iov, nr_segs);
3566
3567                         if (end > isize)
3568                                 vmtruncate(inode, isize);
3569                 }
3570         }
3571         if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
3572                 goto retry;
3573
3574         if (orphan) {
3575                 int err;
3576
3577                 /* Credits for sb + inode write */
3578                 handle = ext4_journal_start(inode, 2);
3579                 if (IS_ERR(handle)) {
3580                         /* This is really bad luck. We've written the data
3581                          * but cannot extend i_size. Bail out and pretend
3582                          * the write failed... */
3583                         ret = PTR_ERR(handle);
3584                         if (inode->i_nlink)
3585                                 ext4_orphan_del(NULL, inode);
3586
3587                         goto out;
3588                 }
3589                 if (inode->i_nlink)
3590                         ext4_orphan_del(handle, inode);
3591                 if (ret > 0) {
3592                         loff_t end = offset + ret;
3593                         if (end > inode->i_size) {
3594                                 ei->i_disksize = end;
3595                                 i_size_write(inode, end);
3596                                 /*
3597                                  * We're going to return a positive `ret'
3598                                  * here due to non-zero-length I/O, so there's
3599                                  * no way of reporting error returns from
3600                                  * ext4_mark_inode_dirty() to userspace.  So
3601                                  * ignore it.
3602                                  */
3603                                 ext4_mark_inode_dirty(handle, inode);
3604                         }
3605                 }
3606                 err = ext4_journal_stop(handle);
3607                 if (ret == 0)
3608                         ret = err;
3609         }
3610 out:
3611         return ret;
3612 }
3613
3614 /*
3615  * ext4_get_block used when preparing for a DIO write or buffer write.
3616  * We allocate an uinitialized extent if blocks haven't been allocated.
3617  * The extent will be converted to initialized after the IO is complete.
3618  */
3619 static int ext4_get_block_write(struct inode *inode, sector_t iblock,
3620                    struct buffer_head *bh_result, int create)
3621 {
3622         ext4_debug("ext4_get_block_write: inode %lu, create flag %d\n",
3623                    inode->i_ino, create);
3624         return _ext4_get_block(inode, iblock, bh_result,
3625                                EXT4_GET_BLOCKS_IO_CREATE_EXT);
3626 }
3627
3628 static void ext4_end_io_dio(struct kiocb *iocb, loff_t offset,
3629                             ssize_t size, void *private, int ret,
3630                             bool is_async)
3631 {
3632         ext4_io_end_t *io_end = iocb->private;
3633         struct workqueue_struct *wq;
3634         unsigned long flags;
3635         struct ext4_inode_info *ei;
3636
3637         /* if not async direct IO or dio with 0 bytes write, just return */
3638         if (!io_end || !size)
3639                 goto out;
3640
3641         ext_debug("ext4_end_io_dio(): io_end 0x%p"
3642                   "for inode %lu, iocb 0x%p, offset %llu, size %llu\n",
3643                   iocb->private, io_end->inode->i_ino, iocb, offset,
3644                   size);
3645
3646         /* if not aio dio with unwritten extents, just free io and return */
3647         if (!(io_end->flag & EXT4_IO_END_UNWRITTEN)) {
3648                 ext4_free_io_end(io_end);
3649                 iocb->private = NULL;
3650 out:
3651                 if (is_async)
3652                         aio_complete(iocb, ret, 0);
3653                 return;
3654         }
3655
3656         io_end->offset = offset;
3657         io_end->size = size;
3658         if (is_async) {
3659                 io_end->iocb = iocb;
3660                 io_end->result = ret;
3661         }
3662         wq = EXT4_SB(io_end->inode->i_sb)->dio_unwritten_wq;
3663
3664         /* Add the io_end to per-inode completed aio dio list*/
3665         ei = EXT4_I(io_end->inode);
3666         spin_lock_irqsave(&ei->i_completed_io_lock, flags);
3667         list_add_tail(&io_end->list, &ei->i_completed_io_list);
3668         spin_unlock_irqrestore(&ei->i_completed_io_lock, flags);
3669
3670         /* queue the work to convert unwritten extents to written */
3671         queue_work(wq, &io_end->work);
3672         iocb->private = NULL;
3673 }
3674
3675 static void ext4_end_io_buffer_write(struct buffer_head *bh, int uptodate)
3676 {
3677         ext4_io_end_t *io_end = bh->b_private;
3678         struct workqueue_struct *wq;
3679         struct inode *inode;
3680         unsigned long flags;
3681
3682         if (!test_clear_buffer_uninit(bh) || !io_end)
3683                 goto out;
3684
3685         if (!(io_end->inode->i_sb->s_flags & MS_ACTIVE)) {
3686                 printk("sb umounted, discard end_io request for inode %lu\n",
3687                         io_end->inode->i_ino);
3688                 ext4_free_io_end(io_end);
3689                 goto out;
3690         }
3691
3692         io_end->flag = EXT4_IO_END_UNWRITTEN;
3693         inode = io_end->inode;
3694
3695         /* Add the io_end to per-inode completed io list*/
3696         spin_lock_irqsave(&EXT4_I(inode)->i_completed_io_lock, flags);
3697         list_add_tail(&io_end->list, &EXT4_I(inode)->i_completed_io_list);
3698         spin_unlock_irqrestore(&EXT4_I(inode)->i_completed_io_lock, flags);
3699
3700         wq = EXT4_SB(inode->i_sb)->dio_unwritten_wq;
3701         /* queue the work to convert unwritten extents to written */
3702         queue_work(wq, &io_end->work);
3703 out:
3704         bh->b_private = NULL;
3705         bh->b_end_io = NULL;
3706         clear_buffer_uninit(bh);
3707         end_buffer_async_write(bh, uptodate);
3708 }
3709
3710 static int ext4_set_bh_endio(struct buffer_head *bh, struct inode *inode)
3711 {
3712         ext4_io_end_t *io_end;
3713         struct page *page = bh->b_page;
3714         loff_t offset = (sector_t)page->index << PAGE_CACHE_SHIFT;
3715         size_t size = bh->b_size;
3716
3717 retry:
3718         io_end = ext4_init_io_end(inode, GFP_ATOMIC);
3719         if (!io_end) {
3720                 if (printk_ratelimit())
3721                         printk(KERN_WARNING "%s: allocation fail\n", __func__);
3722                 schedule();
3723                 goto retry;
3724         }
3725         io_end->offset = offset;
3726         io_end->size = size;
3727         /*
3728          * We need to hold a reference to the page to make sure it
3729          * doesn't get evicted before ext4_end_io_work() has a chance
3730          * to convert the extent from written to unwritten.
3731          */
3732         io_end->page = page;
3733         get_page(io_end->page);
3734
3735         bh->b_private = io_end;
3736         bh->b_end_io = ext4_end_io_buffer_write;
3737         return 0;
3738 }
3739
3740 /*
3741  * For ext4 extent files, ext4 will do direct-io write to holes,
3742  * preallocated extents, and those write extend the file, no need to
3743  * fall back to buffered IO.
3744  *
3745  * For holes, we fallocate those blocks, mark them as unintialized
3746  * If those blocks were preallocated, we mark sure they are splited, but
3747  * still keep the range to write as unintialized.
3748  *
3749  * The unwrritten extents will be converted to written when DIO is completed.
3750  * For async direct IO, since the IO may still pending when return, we
3751  * set up an end_io call back function, which will do the convertion
3752  * when async direct IO completed.
3753  *
3754  * If the O_DIRECT write will extend the file then add this inode to the
3755  * orphan list.  So recovery will truncate it back to the original size
3756  * if the machine crashes during the write.
3757  *
3758  */
3759 static ssize_t ext4_ext_direct_IO(int rw, struct kiocb *iocb,
3760                               const struct iovec *iov, loff_t offset,
3761                               unsigned long nr_segs)
3762 {
3763         struct file *file = iocb->ki_filp;
3764         struct inode *inode = file->f_mapping->host;
3765         ssize_t ret;
3766         size_t count = iov_length(iov, nr_segs);
3767
3768         loff_t final_size = offset + count;
3769         if (rw == WRITE && final_size <= inode->i_size) {
3770                 /*
3771                  * We could direct write to holes and fallocate.
3772                  *
3773                  * Allocated blocks to fill the hole are marked as uninitialized
3774                  * to prevent paralel buffered read to expose the stale data
3775                  * before DIO complete the data IO.
3776                  *
3777                  * As to previously fallocated extents, ext4 get_block
3778                  * will just simply mark the buffer mapped but still
3779                  * keep the extents uninitialized.
3780                  *
3781                  * for non AIO case, we will convert those unwritten extents
3782                  * to written after return back from blockdev_direct_IO.
3783                  *
3784                  * for async DIO, the conversion needs to be defered when
3785                  * the IO is completed. The ext4 end_io callback function
3786                  * will be called to take care of the conversion work.
3787                  * Here for async case, we allocate an io_end structure to
3788                  * hook to the iocb.
3789                  */
3790                 iocb->private = NULL;
3791                 EXT4_I(inode)->cur_aio_dio = NULL;
3792                 if (!is_sync_kiocb(iocb)) {
3793                         iocb->private = ext4_init_io_end(inode, GFP_NOFS);
3794                         if (!iocb->private)
3795                                 return -ENOMEM;
3796                         /*
3797                          * we save the io structure for current async
3798                          * direct IO, so that later ext4_map_blocks()
3799                          * could flag the io structure whether there
3800                          * is a unwritten extents needs to be converted
3801                          * when IO is completed.
3802                          */
3803                         EXT4_I(inode)->cur_aio_dio = iocb->private;
3804                 }
3805
3806                 ret = blockdev_direct_IO(rw, iocb, inode,
3807                                          inode->i_sb->s_bdev, iov,
3808                                          offset, nr_segs,
3809                                          ext4_get_block_write,
3810                                          ext4_end_io_dio);
3811                 if (iocb->private)
3812                         EXT4_I(inode)->cur_aio_dio = NULL;
3813                 /*
3814                  * The io_end structure takes a reference to the inode,
3815                  * that structure needs to be destroyed and the
3816                  * reference to the inode need to be dropped, when IO is
3817                  * complete, even with 0 byte write, or failed.
3818                  *
3819                  * In the successful AIO DIO case, the io_end structure will be
3820                  * desctroyed and the reference to the inode will be dropped
3821                  * after the end_io call back function is called.
3822                  *
3823                  * In the case there is 0 byte write, or error case, since
3824                  * VFS direct IO won't invoke the end_io call back function,
3825                  * we need to free the end_io structure here.
3826                  */
3827                 if (ret != -EIOCBQUEUED && ret <= 0 && iocb->private) {
3828                         ext4_free_io_end(iocb->private);
3829                         iocb->private = NULL;
3830                 } else if (ret > 0 && ext4_test_inode_state(inode,
3831                                                 EXT4_STATE_DIO_UNWRITTEN)) {
3832                         int err;
3833                         /*
3834                          * for non AIO case, since the IO is already
3835                          * completed, we could do the convertion right here
3836                          */
3837                         err = ext4_convert_unwritten_extents(inode,
3838                                                              offset, ret);
3839                         if (err < 0)
3840                                 ret = err;
3841                         ext4_clear_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN);
3842                 }
3843                 return ret;
3844         }
3845
3846         /* for write the the end of file case, we fall back to old way */
3847         return ext4_ind_direct_IO(rw, iocb, iov, offset, nr_segs);
3848 }
3849
3850 static ssize_t ext4_direct_IO(int rw, struct kiocb *iocb,
3851                               const struct iovec *iov, loff_t offset,
3852                               unsigned long nr_segs)
3853 {
3854         struct file *file = iocb->ki_filp;
3855         struct inode *inode = file->f_mapping->host;
3856
3857         if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
3858                 return ext4_ext_direct_IO(rw, iocb, iov, offset, nr_segs);
3859
3860         return ext4_ind_direct_IO(rw, iocb, iov, offset, nr_segs);
3861 }
3862
3863 /*
3864  * Pages can be marked dirty completely asynchronously from ext4's journalling
3865  * activity.  By filemap_sync_pte(), try_to_unmap_one(), etc.  We cannot do
3866  * much here because ->set_page_dirty is called under VFS locks.  The page is
3867  * not necessarily locked.
3868  *
3869  * We cannot just dirty the page and leave attached buffers clean, because the
3870  * buffers' dirty state is "definitive".  We cannot just set the buffers dirty
3871  * or jbddirty because all the journalling code will explode.
3872  *
3873  * So what we do is to mark the page "pending dirty" and next time writepage
3874  * is called, propagate that into the buffers appropriately.
3875  */
3876 static int ext4_journalled_set_page_dirty(struct page *page)
3877 {
3878         SetPageChecked(page);
3879         return __set_page_dirty_nobuffers(page);
3880 }
3881
3882 static const struct address_space_operations ext4_ordered_aops = {
3883         .readpage               = ext4_readpage,
3884         .readpages              = ext4_readpages,
3885         .writepage              = ext4_writepage,
3886         .sync_page              = block_sync_page,
3887         .write_begin            = ext4_write_begin,
3888         .write_end              = ext4_ordered_write_end,
3889         .bmap                   = ext4_bmap,
3890         .invalidatepage         = ext4_invalidatepage,
3891         .releasepage            = ext4_releasepage,
3892         .direct_IO              = ext4_direct_IO,
3893         .migratepage            = buffer_migrate_page,
3894         .is_partially_uptodate  = block_is_partially_uptodate,
3895         .error_remove_page      = generic_error_remove_page,
3896 };
3897
3898 static const struct address_space_operations ext4_writeback_aops = {
3899         .readpage               = ext4_readpage,
3900         .readpages              = ext4_readpages,
3901         .writepage              = ext4_writepage,
3902         .sync_page              = block_sync_page,
3903         .write_begin            = ext4_write_begin,
3904         .write_end              = ext4_writeback_write_end,
3905         .bmap                   = ext4_bmap,
3906         .invalidatepage         = ext4_invalidatepage,
3907         .releasepage            = ext4_releasepage,
3908         .direct_IO              = ext4_direct_IO,
3909         .migratepage            = buffer_migrate_page,
3910         .is_partially_uptodate  = block_is_partially_uptodate,
3911         .error_remove_page      = generic_error_remove_page,
3912 };
3913
3914 static const struct address_space_operations ext4_journalled_aops = {
3915         .readpage               = ext4_readpage,
3916         .readpages              = ext4_readpages,
3917         .writepage              = ext4_writepage,
3918         .sync_page              = block_sync_page,
3919         .write_begin            = ext4_write_begin,
3920         .write_end              = ext4_journalled_write_end,
3921         .set_page_dirty         = ext4_journalled_set_page_dirty,
3922         .bmap                   = ext4_bmap,
3923         .invalidatepage         = ext4_invalidatepage,
3924         .releasepage            = ext4_releasepage,
3925         .is_partially_uptodate  = block_is_partially_uptodate,
3926         .error_remove_page      = generic_error_remove_page,
3927 };
3928
3929 static const struct address_space_operations ext4_da_aops = {
3930         .readpage               = ext4_readpage,
3931         .readpages              = ext4_readpages,
3932         .writepage              = ext4_writepage,
3933         .writepages             = ext4_da_writepages,
3934         .sync_page              = block_sync_page,
3935         .write_begin            = ext4_da_write_begin,
3936         .write_end              = ext4_da_write_end,
3937         .bmap                   = ext4_bmap,
3938         .invalidatepage         = ext4_da_invalidatepage,
3939         .releasepage            = ext4_releasepage,
3940         .direct_IO              = ext4_direct_IO,
3941         .migratepage            = buffer_migrate_page,
3942         .is_partially_uptodate  = block_is_partially_uptodate,
3943         .error_remove_page      = generic_error_remove_page,
3944 };
3945
3946 void ext4_set_aops(struct inode *inode)
3947 {
3948         if (ext4_should_order_data(inode) &&
3949                 test_opt(inode->i_sb, DELALLOC))
3950                 inode->i_mapping->a_ops = &ext4_da_aops;
3951         else if (ext4_should_order_data(inode))
3952                 inode->i_mapping->a_ops = &ext4_ordered_aops;
3953         else if (ext4_should_writeback_data(inode) &&
3954                  test_opt(inode->i_sb, DELALLOC))
3955                 inode->i_mapping->a_ops = &ext4_da_aops;
3956         else if (ext4_should_writeback_data(inode))
3957                 inode->i_mapping->a_ops = &ext4_writeback_aops;
3958         else
3959                 inode->i_mapping->a_ops = &ext4_journalled_aops;
3960 }
3961
3962 /*
3963  * ext4_block_truncate_page() zeroes out a mapping from file offset `from'
3964  * up to the end of the block which corresponds to `from'.
3965  * This required during truncate. We need to physically zero the tail end
3966  * of that block so it doesn't yield old data if the file is later grown.
3967  */
3968 int ext4_block_truncate_page(handle_t *handle,
3969                 struct address_space *mapping, loff_t from)
3970 {
3971         ext4_fsblk_t index = from >> PAGE_CACHE_SHIFT;
3972         unsigned offset = from & (PAGE_CACHE_SIZE-1);
3973         unsigned blocksize, length, pos;
3974         ext4_lblk_t iblock;
3975         struct inode *inode = mapping->host;
3976         struct buffer_head *bh;
3977         struct page *page;
3978         int err = 0;
3979
3980         page = find_or_create_page(mapping, from >> PAGE_CACHE_SHIFT,
3981                                    mapping_gfp_mask(mapping) & ~__GFP_FS);
3982         if (!page)
3983                 return -EINVAL;
3984
3985         blocksize = inode->i_sb->s_blocksize;
3986         length = blocksize - (offset & (blocksize - 1));
3987         iblock = index << (PAGE_CACHE_SHIFT - inode->i_sb->s_blocksize_bits);
3988
3989         if (!page_has_buffers(page))
3990                 create_empty_buffers(page, blocksize, 0);
3991
3992         /* Find the buffer that contains "offset" */
3993         bh = page_buffers(page);
3994         pos = blocksize;
3995         while (offset >= pos) {
3996                 bh = bh->b_this_page;
3997                 iblock++;
3998                 pos += blocksize;
3999         }
4000
4001         err = 0;
4002         if (buffer_freed(bh)) {
4003                 BUFFER_TRACE(bh, "freed: skip");
4004                 goto unlock;
4005         }
4006
4007         if (!buffer_mapped(bh)) {
4008                 BUFFER_TRACE(bh, "unmapped");
4009                 ext4_get_block(inode, iblock, bh, 0);
4010                 /* unmapped? It's a hole - nothing to do */
4011                 if (!buffer_mapped(bh)) {
4012                         BUFFER_TRACE(bh, "still unmapped");
4013                         goto unlock;
4014                 }
4015         }
4016
4017         /* Ok, it's mapped. Make sure it's up-to-date */
4018         if (PageUptodate(page))
4019                 set_buffer_uptodate(bh);
4020
4021         if (!buffer_uptodate(bh)) {
4022                 err = -EIO;
4023                 ll_rw_block(READ, 1, &bh);
4024                 wait_on_buffer(bh);
4025                 /* Uhhuh. Read error. Complain and punt. */
4026                 if (!buffer_uptodate(bh))
4027                         goto unlock;
4028         }
4029
4030         if (ext4_should_journal_data(inode)) {
4031                 BUFFER_TRACE(bh, "get write access");
4032                 err = ext4_journal_get_write_access(handle, bh);
4033                 if (err)
4034                         goto unlock;
4035         }
4036
4037         zero_user(page, offset, length);
4038
4039         BUFFER_TRACE(bh, "zeroed end of block");
4040
4041         err = 0;
4042         if (ext4_should_journal_data(inode)) {
4043                 err = ext4_handle_dirty_metadata(handle, inode, bh);
4044         } else {
4045                 if (ext4_should_order_data(inode))
4046                         err = ext4_jbd2_file_inode(handle, inode);
4047                 mark_buffer_dirty(bh);
4048         }
4049
4050 unlock:
4051         unlock_page(page);
4052         page_cache_release(page);
4053         return err;
4054 }
4055
4056 /*
4057  * Probably it should be a library function... search for first non-zero word
4058  * or memcmp with zero_page, whatever is better for particular architecture.
4059  * Linus?
4060  */
4061 static inline int all_zeroes(__le32 *p, __le32 *q)
4062 {
4063         while (p < q)
4064                 if (*p++)
4065                         return 0;
4066         return 1;
4067 }
4068
4069 /**
4070  *      ext4_find_shared - find the indirect blocks for partial truncation.
4071  *      @inode:   inode in question
4072  *      @depth:   depth of the affected branch
4073  *      @offsets: offsets of pointers in that branch (see ext4_block_to_path)
4074  *      @chain:   place to store the pointers to partial indirect blocks
4075  *      @top:     place to the (detached) top of branch
4076  *
4077  *      This is a helper function used by ext4_truncate().
4078  *
4079  *      When we do truncate() we may have to clean the ends of several
4080  *      indirect blocks but leave the blocks themselves alive. Block is
4081  *      partially truncated if some data below the new i_size is refered
4082  *      from it (and it is on the path to the first completely truncated
4083  *      data block, indeed).  We have to free the top of that path along
4084  *      with everything to the right of the path. Since no allocation
4085  *      past the truncation point is possible until ext4_truncate()
4086  *      finishes, we may safely do the latter, but top of branch may
4087  *      require special attention - pageout below the truncation point
4088  *      might try to populate it.
4089  *
4090  *      We atomically detach the top of branch from the tree, store the
4091  *      block number of its root in *@top, pointers to buffer_heads of
4092  *      partially truncated blocks - in @chain[].bh and pointers to
4093  *      their last elements that should not be removed - in
4094  *      @chain[].p. Return value is the pointer to last filled element
4095  *      of @chain.
4096  *
4097  *      The work left to caller to do the actual freeing of subtrees:
4098  *              a) free the subtree starting from *@top
4099  *              b) free the subtrees whose roots are stored in
4100  *                      (@chain[i].p+1 .. end of @chain[i].bh->b_data)
4101  *              c) free the subtrees growing from the inode past the @chain[0].
4102  *                      (no partially truncated stuff there).  */
4103
4104 static Indirect *ext4_find_shared(struct inode *inode, int depth,
4105                                   ext4_lblk_t offsets[4], Indirect chain[4],
4106                                   __le32 *top)
4107 {
4108         Indirect *partial, *p;
4109         int k, err;
4110
4111         *top = 0;
4112         /* Make k index the deepest non-null offset + 1 */
4113         for (k = depth; k > 1 && !offsets[k-1]; k--)
4114                 ;
4115         partial = ext4_get_branch(inode, k, offsets, chain, &err);
4116         /* Writer: pointers */
4117         if (!partial)
4118                 partial = chain + k-1;
4119         /*
4120          * If the branch acquired continuation since we've looked at it -
4121          * fine, it should all survive and (new) top doesn't belong to us.
4122          */
4123         if (!partial->key && *partial->p)
4124                 /* Writer: end */
4125                 goto no_top;
4126         for (p = partial; (p > chain) && all_zeroes((__le32 *) p->bh->b_data, p->p); p--)
4127                 ;
4128         /*
4129          * OK, we've found the last block that must survive. The rest of our
4130          * branch should be detached before unlocking. However, if that rest
4131          * of branch is all ours and does not grow immediately from the inode
4132          * it's easier to cheat and just decrement partial->p.
4133          */
4134         if (p == chain + k - 1 && p > chain) {
4135                 p->p--;
4136         } else {
4137                 *top = *p->p;
4138                 /* Nope, don't do this in ext4.  Must leave the tree intact */
4139 #if 0
4140                 *p->p = 0;
4141 #endif
4142         }
4143         /* Writer: end */
4144
4145         while (partial > p) {
4146                 brelse(partial->bh);
4147                 partial--;
4148         }
4149 no_top:
4150         return partial;
4151 }
4152
4153 /*
4154  * Zero a number of block pointers in either an inode or an indirect block.
4155  * If we restart the transaction we must again get write access to the
4156  * indirect block for further modification.
4157  *
4158  * We release `count' blocks on disk, but (last - first) may be greater
4159  * than `count' because there can be holes in there.
4160  */
4161 static int ext4_clear_blocks(handle_t *handle, struct inode *inode,
4162                              struct buffer_head *bh,
4163                              ext4_fsblk_t block_to_free,
4164                              unsigned long count, __le32 *first,
4165                              __le32 *last)
4166 {
4167         __le32 *p;
4168         int     flags = EXT4_FREE_BLOCKS_FORGET | EXT4_FREE_BLOCKS_VALIDATED;
4169
4170         if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode))
4171                 flags |= EXT4_FREE_BLOCKS_METADATA;
4172
4173         if (!ext4_data_block_valid(EXT4_SB(inode->i_sb), block_to_free,
4174                                    count)) {
4175                 EXT4_ERROR_INODE(inode, "attempt to clear invalid "
4176                                  "blocks %llu len %lu",
4177                                  (unsigned long long) block_to_free, count);
4178                 return 1;
4179         }
4180
4181         if (try_to_extend_transaction(handle, inode)) {
4182                 if (bh) {
4183                         BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
4184                         ext4_handle_dirty_metadata(handle, inode, bh);
4185                 }
4186                 ext4_mark_inode_dirty(handle, inode);
4187                 ext4_truncate_restart_trans(handle, inode,
4188                                             blocks_for_truncate(inode));
4189                 if (bh) {
4190                         BUFFER_TRACE(bh, "retaking write access");
4191                         ext4_journal_get_write_access(handle, bh);
4192                 }
4193         }
4194
4195         for (p = first; p < last; p++)
4196                 *p = 0;
4197
4198         ext4_free_blocks(handle, inode, 0, block_to_free, count, flags);
4199         return 0;
4200 }
4201
4202 /**
4203  * ext4_free_data - free a list of data blocks
4204  * @handle:     handle for this transaction
4205  * @inode:      inode we are dealing with
4206  * @this_bh:    indirect buffer_head which contains *@first and *@last
4207  * @first:      array of block numbers
4208  * @last:       points immediately past the end of array
4209  *
4210  * We are freeing all blocks refered from that array (numbers are stored as
4211  * little-endian 32-bit) and updating @inode->i_blocks appropriately.
4212  *
4213  * We accumulate contiguous runs of blocks to free.  Conveniently, if these
4214  * blocks are contiguous then releasing them at one time will only affect one
4215  * or two bitmap blocks (+ group descriptor(s) and superblock) and we won't
4216  * actually use a lot of journal space.
4217  *
4218  * @this_bh will be %NULL if @first and @last point into the inode's direct
4219  * block pointers.
4220  */
4221 static void ext4_free_data(handle_t *handle, struct inode *inode,
4222                            struct buffer_head *this_bh,
4223                            __le32 *first, __le32 *last)
4224 {
4225         ext4_fsblk_t block_to_free = 0;    /* Starting block # of a run */
4226         unsigned long count = 0;            /* Number of blocks in the run */
4227         __le32 *block_to_free_p = NULL;     /* Pointer into inode/ind
4228                                                corresponding to
4229                                                block_to_free */
4230         ext4_fsblk_t nr;                    /* Current block # */
4231         __le32 *p;                          /* Pointer into inode/ind
4232                                                for current block */
4233         int err;
4234
4235         if (this_bh) {                          /* For indirect block */
4236                 BUFFER_TRACE(this_bh, "get_write_access");
4237                 err = ext4_journal_get_write_access(handle, this_bh);
4238                 /* Important: if we can't update the indirect pointers
4239                  * to the blocks, we can't free them. */
4240                 if (err)
4241                         return;
4242         }
4243
4244         for (p = first; p < last; p++) {
4245                 nr = le32_to_cpu(*p);
4246                 if (nr) {
4247                         /* accumulate blocks to free if they're contiguous */
4248                         if (count == 0) {
4249                                 block_to_free = nr;
4250                                 block_to_free_p = p;
4251                                 count = 1;
4252                         } else if (nr == block_to_free + count) {
4253                                 count++;
4254                         } else {
4255                                 if (ext4_clear_blocks(handle, inode, this_bh,
4256                                                       block_to_free, count,
4257                                                       block_to_free_p, p))
4258                                         break;
4259                                 block_to_free = nr;
4260                                 block_to_free_p = p;
4261                                 count = 1;
4262                         }
4263                 }
4264         }
4265
4266         if (count > 0)
4267                 ext4_clear_blocks(handle, inode, this_bh, block_to_free,
4268                                   count, block_to_free_p, p);
4269
4270         if (this_bh) {
4271                 BUFFER_TRACE(this_bh, "call ext4_handle_dirty_metadata");
4272
4273                 /*
4274                  * The buffer head should have an attached journal head at this
4275                  * point. However, if the data is corrupted and an indirect
4276                  * block pointed to itself, it would have been detached when
4277                  * the block was cleared. Check for this instead of OOPSing.
4278                  */
4279                 if ((EXT4_JOURNAL(inode) == NULL) || bh2jh(this_bh))
4280                         ext4_handle_dirty_metadata(handle, inode, this_bh);
4281                 else
4282                         EXT4_ERROR_INODE(inode,
4283                                          "circular indirect block detected at "
4284                                          "block %llu",
4285                                 (unsigned long long) this_bh->b_blocknr);
4286         }
4287 }
4288
4289 /**
4290  *      ext4_free_branches - free an array of branches
4291  *      @handle: JBD handle for this transaction
4292  *      @inode: inode we are dealing with
4293  *      @parent_bh: the buffer_head which contains *@first and *@last
4294  *      @first: array of block numbers
4295  *      @last:  pointer immediately past the end of array
4296  *      @depth: depth of the branches to free
4297  *
4298  *      We are freeing all blocks refered from these branches (numbers are
4299  *      stored as little-endian 32-bit) and updating @inode->i_blocks
4300  *      appropriately.
4301  */
4302 static void ext4_free_branches(handle_t *handle, struct inode *inode,
4303                                struct buffer_head *parent_bh,
4304                                __le32 *first, __le32 *last, int depth)
4305 {
4306         ext4_fsblk_t nr;
4307         __le32 *p;
4308
4309         if (ext4_handle_is_aborted(handle))
4310                 return;
4311
4312         if (depth--) {
4313                 struct buffer_head *bh;
4314                 int addr_per_block = EXT4_ADDR_PER_BLOCK(inode->i_sb);
4315                 p = last;
4316                 while (--p >= first) {
4317                         nr = le32_to_cpu(*p);
4318                         if (!nr)
4319                                 continue;               /* A hole */
4320
4321                         if (!ext4_data_block_valid(EXT4_SB(inode->i_sb),
4322                                                    nr, 1)) {
4323                                 EXT4_ERROR_INODE(inode,
4324                                                  "invalid indirect mapped "
4325                                                  "block %lu (level %d)",
4326                                                  (unsigned long) nr, depth);
4327                                 break;
4328                         }
4329
4330                         /* Go read the buffer for the next level down */
4331                         bh = sb_bread(inode->i_sb, nr);
4332
4333                         /*
4334                          * A read failure? Report error and clear slot
4335                          * (should be rare).
4336                          */
4337                         if (!bh) {
4338                                 EXT4_ERROR_INODE_BLOCK(inode, nr,
4339                                                        "Read failure");
4340                                 continue;
4341                         }
4342
4343                         /* This zaps the entire block.  Bottom up. */
4344                         BUFFER_TRACE(bh, "free child branches");
4345                         ext4_free_branches(handle, inode, bh,
4346                                         (__le32 *) bh->b_data,
4347                                         (__le32 *) bh->b_data + addr_per_block,
4348                                         depth);
4349
4350                         /*
4351                          * Everything below this this pointer has been
4352                          * released.  Now let this top-of-subtree go.
4353                          *
4354                          * We want the freeing of this indirect block to be
4355                          * atomic in the journal with the updating of the
4356                          * bitmap block which owns it.  So make some room in
4357                          * the journal.
4358                          *
4359                          * We zero the parent pointer *after* freeing its
4360                          * pointee in the bitmaps, so if extend_transaction()
4361                          * for some reason fails to put the bitmap changes and
4362                          * the release into the same transaction, recovery
4363                          * will merely complain about releasing a free block,
4364                          * rather than leaking blocks.
4365                          */
4366                         if (ext4_handle_is_aborted(handle))
4367                                 return;
4368                         if (try_to_extend_transaction(handle, inode)) {
4369                                 ext4_mark_inode_dirty(handle, inode);
4370                                 ext4_truncate_restart_trans(handle, inode,
4371                                             blocks_for_truncate(inode));
4372                         }
4373
4374                         /*
4375                          * The forget flag here is critical because if
4376                          * we are journaling (and not doing data
4377                          * journaling), we have to make sure a revoke
4378                          * record is written to prevent the journal
4379                          * replay from overwriting the (former)
4380                          * indirect block if it gets reallocated as a
4381                          * data block.  This must happen in the same
4382                          * transaction where the data blocks are
4383                          * actually freed.
4384                          */
4385                         ext4_free_blocks(handle, inode, 0, nr, 1,
4386                                          EXT4_FREE_BLOCKS_METADATA|
4387                                          EXT4_FREE_BLOCKS_FORGET);
4388
4389                         if (parent_bh) {
4390                                 /*
4391                                  * The block which we have just freed is
4392                                  * pointed to by an indirect block: journal it
4393                                  */
4394                                 BUFFER_TRACE(parent_bh, "get_write_access");
4395                                 if (!ext4_journal_get_write_access(handle,
4396                                                                    parent_bh)){
4397                                         *p = 0;
4398                                         BUFFER_TRACE(parent_bh,
4399                                         "call ext4_handle_dirty_metadata");
4400                                         ext4_handle_dirty_metadata(handle,
4401                                                                    inode,
4402                                                                    parent_bh);
4403                                 }
4404                         }
4405                 }
4406         } else {
4407                 /* We have reached the bottom of the tree. */
4408                 BUFFER_TRACE(parent_bh, "free data blocks");
4409                 ext4_free_data(handle, inode, parent_bh, first, last);
4410         }
4411 }
4412
4413 int ext4_can_truncate(struct inode *inode)
4414 {
4415         if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
4416                 return 0;
4417         if (S_ISREG(inode->i_mode))
4418                 return 1;
4419         if (S_ISDIR(inode->i_mode))
4420                 return 1;
4421         if (S_ISLNK(inode->i_mode))
4422                 return !ext4_inode_is_fast_symlink(inode);
4423         return 0;
4424 }
4425
4426 /*
4427  * ext4_truncate()
4428  *
4429  * We block out ext4_get_block() block instantiations across the entire
4430  * transaction, and VFS/VM ensures that ext4_truncate() cannot run
4431  * simultaneously on behalf of the same inode.
4432  *
4433  * As we work through the truncate and commmit bits of it to the journal there
4434  * is one core, guiding principle: the file's tree must always be consistent on
4435  * disk.  We must be able to restart the truncate after a crash.
4436  *
4437  * The file's tree may be transiently inconsistent in memory (although it
4438  * probably isn't), but whenever we close off and commit a journal transaction,
4439  * the contents of (the filesystem + the journal) must be consistent and
4440  * restartable.  It's pretty simple, really: bottom up, right to left (although
4441  * left-to-right works OK too).
4442  *
4443  * Note that at recovery time, journal replay occurs *before* the restart of
4444  * truncate against the orphan inode list.
4445  *
4446  * The committed inode has the new, desired i_size (which is the same as
4447  * i_disksize in this case).  After a crash, ext4_orphan_cleanup() will see
4448  * that this inode's truncate did not complete and it will again call
4449  * ext4_truncate() to have another go.  So there will be instantiated blocks
4450  * to the right of the truncation point in a crashed ext4 filesystem.  But
4451  * that's fine - as long as they are linked from the inode, the post-crash
4452  * ext4_truncate() run will find them and release them.
4453  */
4454 void ext4_truncate(struct inode *inode)
4455 {
4456         handle_t *handle;
4457         struct ext4_inode_info *ei = EXT4_I(inode);
4458         __le32 *i_data = ei->i_data;
4459         int addr_per_block = EXT4_ADDR_PER_BLOCK(inode->i_sb);
4460         struct address_space *mapping = inode->i_mapping;
4461         ext4_lblk_t offsets[4];
4462         Indirect chain[4];
4463         Indirect *partial;
4464         __le32 nr = 0;
4465         int n;
4466         ext4_lblk_t last_block;
4467         unsigned blocksize = inode->i_sb->s_blocksize;
4468
4469         if (!ext4_can_truncate(inode))
4470                 return;
4471
4472         ext4_clear_inode_flag(inode, EXT4_INODE_EOFBLOCKS);
4473
4474         if (inode->i_size == 0 && !test_opt(inode->i_sb, NO_AUTO_DA_ALLOC))
4475                 ext4_set_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE);
4476
4477         if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
4478                 ext4_ext_truncate(inode);
4479                 return;
4480         }
4481
4482         handle = start_transaction(inode);
4483         if (IS_ERR(handle))
4484                 return;         /* AKPM: return what? */
4485
4486         last_block = (inode->i_size + blocksize-1)
4487                                         >> EXT4_BLOCK_SIZE_BITS(inode->i_sb);
4488
4489         if (inode->i_size & (blocksize - 1))
4490                 if (ext4_block_truncate_page(handle, mapping, inode->i_size))
4491                         goto out_stop;
4492
4493         n = ext4_block_to_path(inode, last_block, offsets, NULL);
4494         if (n == 0)
4495                 goto out_stop;  /* error */
4496
4497         /*
4498          * OK.  This truncate is going to happen.  We add the inode to the
4499          * orphan list, so that if this truncate spans multiple transactions,
4500          * and we crash, we will resume the truncate when the filesystem
4501          * recovers.  It also marks the inode dirty, to catch the new size.
4502          *
4503          * Implication: the file must always be in a sane, consistent
4504          * truncatable state while each transaction commits.
4505          */
4506         if (ext4_orphan_add(handle, inode))
4507                 goto out_stop;
4508
4509         /*
4510          * From here we block out all ext4_get_block() callers who want to
4511          * modify the block allocation tree.
4512          */
4513         down_write(&ei->i_data_sem);
4514
4515         ext4_discard_preallocations(inode);
4516
4517         /*
4518          * The orphan list entry will now protect us from any crash which
4519          * occurs before the truncate completes, so it is now safe to propagate
4520          * the new, shorter inode size (held for now in i_size) into the
4521          * on-disk inode. We do this via i_disksize, which is the value which
4522          * ext4 *really* writes onto the disk inode.
4523          */
4524         ei->i_disksize = inode->i_size;
4525
4526         if (n == 1) {           /* direct blocks */
4527                 ext4_free_data(handle, inode, NULL, i_data+offsets[0],
4528                                i_data + EXT4_NDIR_BLOCKS);
4529                 goto do_indirects;
4530         }
4531
4532         partial = ext4_find_shared(inode, n, offsets, chain, &nr);
4533         /* Kill the top of shared branch (not detached) */
4534         if (nr) {
4535                 if (partial == chain) {
4536                         /* Shared branch grows from the inode */
4537                         ext4_free_branches(handle, inode, NULL,
4538                                            &nr, &nr+1, (chain+n-1) - partial);
4539                         *partial->p = 0;
4540                         /*
4541                          * We mark the inode dirty prior to restart,
4542                          * and prior to stop.  No need for it here.
4543                          */
4544                 } else {
4545                         /* Shared branch grows from an indirect block */
4546                         BUFFER_TRACE(partial->bh, "get_write_access");
4547                         ext4_free_branches(handle, inode, partial->bh,
4548                                         partial->p,
4549                                         partial->p+1, (chain+n-1) - partial);
4550                 }
4551         }
4552         /* Clear the ends of indirect blocks on the shared branch */
4553         while (partial > chain) {
4554                 ext4_free_branches(handle, inode, partial->bh, partial->p + 1,
4555                                    (__le32*)partial->bh->b_data+addr_per_block,
4556                                    (chain+n-1) - partial);
4557                 BUFFER_TRACE(partial->bh, "call brelse");
4558                 brelse(partial->bh);
4559                 partial--;
4560         }
4561 do_indirects:
4562         /* Kill the remaining (whole) subtrees */
4563         switch (offsets[0]) {
4564         default:
4565                 nr = i_data[EXT4_IND_BLOCK];
4566                 if (nr) {
4567                         ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 1);
4568                         i_data[EXT4_IND_BLOCK] = 0;
4569                 }
4570         case EXT4_IND_BLOCK:
4571                 nr = i_data[EXT4_DIND_BLOCK];
4572                 if (nr) {
4573                         ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 2);
4574                         i_data[EXT4_DIND_BLOCK] = 0;
4575                 }
4576         case EXT4_DIND_BLOCK:
4577                 nr = i_data[EXT4_TIND_BLOCK];
4578                 if (nr) {
4579                         ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 3);
4580                         i_data[EXT4_TIND_BLOCK] = 0;
4581                 }
4582         case EXT4_TIND_BLOCK:
4583                 ;
4584         }
4585
4586         up_write(&ei->i_data_sem);
4587         inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
4588         ext4_mark_inode_dirty(handle, inode);
4589
4590         /*
4591          * In a multi-transaction truncate, we only make the final transaction
4592          * synchronous
4593          */
4594         if (IS_SYNC(inode))
4595                 ext4_handle_sync(handle);
4596 out_stop:
4597         /*
4598          * If this was a simple ftruncate(), and the file will remain alive
4599          * then we need to clear up the orphan record which we created above.
4600          * However, if this was a real unlink then we were called by
4601          * ext4_delete_inode(), and we allow that function to clean up the
4602          * orphan info for us.
4603          */
4604         if (inode->i_nlink)
4605                 ext4_orphan_del(handle, inode);
4606
4607         ext4_journal_stop(handle);
4608 }
4609
4610 /*
4611  * ext4_get_inode_loc returns with an extra refcount against the inode's
4612  * underlying buffer_head on success. If 'in_mem' is true, we have all
4613  * data in memory that is needed to recreate the on-disk version of this
4614  * inode.
4615  */
4616 static int __ext4_get_inode_loc(struct inode *inode,
4617                                 struct ext4_iloc *iloc, int in_mem)
4618 {
4619         struct ext4_group_desc  *gdp;
4620         struct buffer_head      *bh;
4621         struct super_block      *sb = inode->i_sb;
4622         ext4_fsblk_t            block;
4623         int                     inodes_per_block, inode_offset;
4624
4625         iloc->bh = NULL;
4626         if (!ext4_valid_inum(sb, inode->i_ino))
4627                 return -EIO;
4628
4629         iloc->block_group = (inode->i_ino - 1) / EXT4_INODES_PER_GROUP(sb);
4630         gdp = ext4_get_group_desc(sb, iloc->block_group, NULL);
4631         if (!gdp)
4632                 return -EIO;
4633
4634         /*
4635          * Figure out the offset within the block group inode table
4636          */
4637         inodes_per_block = (EXT4_BLOCK_SIZE(sb) / EXT4_INODE_SIZE(sb));
4638         inode_offset = ((inode->i_ino - 1) %
4639                         EXT4_INODES_PER_GROUP(sb));
4640         block = ext4_inode_table(sb, gdp) + (inode_offset / inodes_per_block);
4641         iloc->offset = (inode_offset % inodes_per_block) * EXT4_INODE_SIZE(sb);
4642
4643         bh = sb_getblk(sb, block);
4644         if (!bh) {
4645                 EXT4_ERROR_INODE_BLOCK(inode, block,
4646                                        "unable to read itable block");
4647                 return -EIO;
4648         }
4649         if (!buffer_uptodate(bh)) {
4650                 lock_buffer(bh);
4651
4652                 /*
4653                  * If the buffer has the write error flag, we have failed
4654                  * to write out another inode in the same block.  In this
4655                  * case, we don't have to read the block because we may
4656                  * read the old inode data successfully.
4657                  */
4658                 if (buffer_write_io_error(bh) && !buffer_uptodate(bh))
4659                         set_buffer_uptodate(bh);
4660
4661                 if (buffer_uptodate(bh)) {
4662                         /* someone brought it uptodate while we waited */
4663                         unlock_buffer(bh);
4664                         goto has_buffer;
4665                 }
4666
4667                 /*
4668                  * If we have all information of the inode in memory and this
4669                  * is the only valid inode in the block, we need not read the
4670                  * block.
4671                  */
4672                 if (in_mem) {
4673                         struct buffer_head *bitmap_bh;
4674                         int i, start;
4675
4676                         start = inode_offset & ~(inodes_per_block - 1);
4677
4678                         /* Is the inode bitmap in cache? */
4679                         bitmap_bh = sb_getblk(sb, ext4_inode_bitmap(sb, gdp));
4680                         if (!bitmap_bh)
4681                                 goto make_io;
4682
4683                         /*
4684                          * If the inode bitmap isn't in cache then the
4685                          * optimisation may end up performing two reads instead
4686                          * of one, so skip it.
4687                          */
4688                         if (!buffer_uptodate(bitmap_bh)) {
4689                                 brelse(bitmap_bh);
4690                                 goto make_io;
4691                         }
4692                         for (i = start; i < start + inodes_per_block; i++) {
4693                                 if (i == inode_offset)
4694                                         continue;
4695                                 if (ext4_test_bit(i, bitmap_bh->b_data))
4696                                         break;
4697                         }
4698                         brelse(bitmap_bh);
4699                         if (i == start + inodes_per_block) {
4700                                 /* all other inodes are free, so skip I/O */
4701                                 memset(bh->b_data, 0, bh->b_size);
4702                                 set_buffer_uptodate(bh);
4703                                 unlock_buffer(bh);
4704                                 goto has_buffer;
4705                         }
4706                 }
4707
4708 make_io:
4709                 /*
4710                  * If we need to do any I/O, try to pre-readahead extra
4711                  * blocks from the inode table.
4712                  */
4713                 if (EXT4_SB(sb)->s_inode_readahead_blks) {
4714                         ext4_fsblk_t b, end, table;
4715                         unsigned num;
4716
4717                         table = ext4_inode_table(sb, gdp);
4718                         /* s_inode_readahead_blks is always a power of 2 */
4719                         b = block & ~(EXT4_SB(sb)->s_inode_readahead_blks-1);
4720                         if (table > b)
4721                                 b = table;
4722                         end = b + EXT4_SB(sb)->s_inode_readahead_blks;
4723                         num = EXT4_INODES_PER_GROUP(sb);
4724                         if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
4725                                        EXT4_FEATURE_RO_COMPAT_GDT_CSUM))
4726                                 num -= ext4_itable_unused_count(sb, gdp);
4727                         table += num / inodes_per_block;
4728                         if (end > table)
4729                                 end = table;
4730                         while (b <= end)
4731                                 sb_breadahead(sb, b++);
4732                 }
4733
4734                 /*
4735                  * There are other valid inodes in the buffer, this inode
4736                  * has in-inode xattrs, or we don't have this inode in memory.
4737                  * Read the block from disk.
4738                  */
4739                 get_bh(bh);
4740                 bh->b_end_io = end_buffer_read_sync;
4741                 submit_bh(READ_META, bh);
4742                 wait_on_buffer(bh);
4743                 if (!buffer_uptodate(bh)) {
4744                         EXT4_ERROR_INODE_BLOCK(inode, block,
4745                                                "unable to read itable block");
4746                         brelse(bh);
4747                         return -EIO;
4748                 }
4749         }
4750 has_buffer:
4751         iloc->bh = bh;
4752         return 0;
4753 }
4754
4755 int ext4_get_inode_loc(struct inode *inode, struct ext4_iloc *iloc)
4756 {
4757         /* We have all inode data except xattrs in memory here. */
4758         return __ext4_get_inode_loc(inode, iloc,
4759                 !ext4_test_inode_state(inode, EXT4_STATE_XATTR));
4760 }
4761
4762 void ext4_set_inode_flags(struct inode *inode)
4763 {
4764         unsigned int flags = EXT4_I(inode)->i_flags;
4765
4766         inode->i_flags &= ~(S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC);
4767         if (flags & EXT4_SYNC_FL)
4768                 inode->i_flags |= S_SYNC;
4769         if (flags & EXT4_APPEND_FL)
4770                 inode->i_flags |= S_APPEND;
4771         if (flags & EXT4_IMMUTABLE_FL)
4772                 inode->i_flags |= S_IMMUTABLE;
4773         if (flags & EXT4_NOATIME_FL)
4774                 inode->i_flags |= S_NOATIME;
4775         if (flags & EXT4_DIRSYNC_FL)
4776                 inode->i_flags |= S_DIRSYNC;
4777 }
4778
4779 /* Propagate flags from i_flags to EXT4_I(inode)->i_flags */
4780 void ext4_get_inode_flags(struct ext4_inode_info *ei)
4781 {
4782         unsigned int vfs_fl;
4783         unsigned long old_fl, new_fl;
4784
4785         do {
4786                 vfs_fl = ei->vfs_inode.i_flags;
4787                 old_fl = ei->i_flags;
4788                 new_fl = old_fl & ~(EXT4_SYNC_FL|EXT4_APPEND_FL|
4789                                 EXT4_IMMUTABLE_FL|EXT4_NOATIME_FL|
4790                                 EXT4_DIRSYNC_FL);
4791                 if (vfs_fl & S_SYNC)
4792                         new_fl |= EXT4_SYNC_FL;
4793                 if (vfs_fl & S_APPEND)
4794                         new_fl |= EXT4_APPEND_FL;
4795                 if (vfs_fl & S_IMMUTABLE)
4796                         new_fl |= EXT4_IMMUTABLE_FL;
4797                 if (vfs_fl & S_NOATIME)
4798                         new_fl |= EXT4_NOATIME_FL;
4799                 if (vfs_fl & S_DIRSYNC)
4800                         new_fl |= EXT4_DIRSYNC_FL;
4801         } while (cmpxchg(&ei->i_flags, old_fl, new_fl) != old_fl);
4802 }
4803
4804 static blkcnt_t ext4_inode_blocks(struct ext4_inode *raw_inode,
4805                                   struct ext4_inode_info *ei)
4806 {
4807         blkcnt_t i_blocks ;
4808         struct inode *inode = &(ei->vfs_inode);
4809         struct super_block *sb = inode->i_sb;
4810
4811         if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
4812                                 EXT4_FEATURE_RO_COMPAT_HUGE_FILE)) {
4813                 /* we are using combined 48 bit field */
4814                 i_blocks = ((u64)le16_to_cpu(raw_inode->i_blocks_high)) << 32 |
4815                                         le32_to_cpu(raw_inode->i_blocks_lo);
4816                 if (ext4_test_inode_flag(inode, EXT4_INODE_HUGE_FILE)) {
4817                         /* i_blocks represent file system block size */
4818                         return i_blocks  << (inode->i_blkbits - 9);
4819                 } else {
4820                         return i_blocks;
4821                 }
4822         } else {
4823                 return le32_to_cpu(raw_inode->i_blocks_lo);
4824         }
4825 }
4826
4827 struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
4828 {
4829         struct ext4_iloc iloc;
4830         struct ext4_inode *raw_inode;
4831         struct ext4_inode_info *ei;
4832         struct inode *inode;
4833         journal_t *journal = EXT4_SB(sb)->s_journal;
4834         long ret;
4835         int block;
4836
4837         inode = iget_locked(sb, ino);
4838         if (!inode)
4839                 return ERR_PTR(-ENOMEM);
4840         if (!(inode->i_state & I_NEW))
4841                 return inode;
4842
4843         ei = EXT4_I(inode);
4844         iloc.bh = 0;
4845
4846         ret = __ext4_get_inode_loc(inode, &iloc, 0);
4847         if (ret < 0)
4848                 goto bad_inode;
4849         raw_inode = ext4_raw_inode(&iloc);
4850         inode->i_mode = le16_to_cpu(raw_inode->i_mode);
4851         inode->i_uid = (uid_t)le16_to_cpu(raw_inode->i_uid_low);
4852         inode->i_gid = (gid_t)le16_to_cpu(raw_inode->i_gid_low);
4853         if (!(test_opt(inode->i_sb, NO_UID32))) {
4854                 inode->i_uid |= le16_to_cpu(raw_inode->i_uid_high) << 16;
4855                 inode->i_gid |= le16_to_cpu(raw_inode->i_gid_high) << 16;
4856         }
4857         inode->i_nlink = le16_to_cpu(raw_inode->i_links_count);
4858
4859         ei->i_state_flags = 0;
4860         ei->i_dir_start_lookup = 0;
4861         ei->i_dtime = le32_to_cpu(raw_inode->i_dtime);
4862         /* We now have enough fields to check if the inode was active or not.
4863          * This is needed because nfsd might try to access dead inodes
4864          * the test is that same one that e2fsck uses
4865          * NeilBrown 1999oct15
4866          */
4867         if (inode->i_nlink == 0) {
4868                 if (inode->i_mode == 0 ||
4869                     !(EXT4_SB(inode->i_sb)->s_mount_state & EXT4_ORPHAN_FS)) {
4870                         /* this inode is deleted */
4871                         ret = -ESTALE;
4872                         goto bad_inode;
4873                 }
4874                 /* The only unlinked inodes we let through here have
4875                  * valid i_mode and are being read by the orphan
4876                  * recovery code: that's fine, we're about to complete
4877                  * the process of deleting those. */
4878         }
4879         ei->i_flags = le32_to_cpu(raw_inode->i_flags);
4880         inode->i_blocks = ext4_inode_blocks(raw_inode, ei);
4881         ei->i_file_acl = le32_to_cpu(raw_inode->i_file_acl_lo);
4882         if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_64BIT))
4883                 ei->i_file_acl |=
4884                         ((__u64)le16_to_cpu(raw_inode->i_file_acl_high)) << 32;
4885         inode->i_size = ext4_isize(raw_inode);
4886         ei->i_disksize = inode->i_size;
4887 #ifdef CONFIG_QUOTA
4888         ei->i_reserved_quota = 0;
4889 #endif
4890         inode->i_generation = le32_to_cpu(raw_inode->i_generation);
4891         ei->i_block_group = iloc.block_group;
4892         ei->i_last_alloc_group = ~0;
4893         /*
4894          * NOTE! The in-memory inode i_data array is in little-endian order
4895          * even on big-endian machines: we do NOT byteswap the block numbers!
4896          */
4897         for (block = 0; block < EXT4_N_BLOCKS; block++)
4898                 ei->i_data[block] = raw_inode->i_block[block];
4899         INIT_LIST_HEAD(&ei->i_orphan);
4900
4901         /*
4902          * Set transaction id's of transactions that have to be committed
4903          * to finish f[data]sync. We set them to currently running transaction
4904          * as we cannot be sure that the inode or some of its metadata isn't
4905          * part of the transaction - the inode could have been reclaimed and
4906          * now it is reread from disk.
4907          */
4908         if (journal) {
4909                 transaction_t *transaction;
4910                 tid_t tid;
4911
4912                 read_lock(&journal->j_state_lock);
4913                 if (journal->j_running_transaction)
4914                         transaction = journal->j_running_transaction;
4915                 else
4916                         transaction = journal->j_committing_transaction;
4917                 if (transaction)
4918                         tid = transaction->t_tid;
4919                 else
4920                         tid = journal->j_commit_sequence;
4921                 read_unlock(&journal->j_state_lock);
4922                 ei->i_sync_tid = tid;
4923                 ei->i_datasync_tid = tid;
4924         }
4925
4926         if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
4927                 ei->i_extra_isize = le16_to_cpu(raw_inode->i_extra_isize);
4928                 if (EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize >
4929                     EXT4_INODE_SIZE(inode->i_sb)) {
4930                         ret = -EIO;
4931                         goto bad_inode;
4932                 }
4933                 if (ei->i_extra_isize == 0) {
4934                         /* The extra space is currently unused. Use it. */
4935                         ei->i_extra_isize = sizeof(struct ext4_inode) -
4936                                             EXT4_GOOD_OLD_INODE_SIZE;
4937                 } else {
4938                         __le32 *magic = (void *)raw_inode +
4939                                         EXT4_GOOD_OLD_INODE_SIZE +
4940                                         ei->i_extra_isize;
4941                         if (*magic == cpu_to_le32(EXT4_XATTR_MAGIC))
4942                                 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
4943                 }
4944         } else
4945                 ei->i_extra_isize = 0;
4946
4947         EXT4_INODE_GET_XTIME(i_ctime, inode, raw_inode);
4948         EXT4_INODE_GET_XTIME(i_mtime, inode, raw_inode);
4949         EXT4_INODE_GET_XTIME(i_atime, inode, raw_inode);
4950         EXT4_EINODE_GET_XTIME(i_crtime, ei, raw_inode);
4951
4952         inode->i_version = le32_to_cpu(raw_inode->i_disk_version);
4953         if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
4954                 if (EXT4_FITS_IN_INODE(raw_inode, ei, i_version_hi))
4955                         inode->i_version |=
4956                         (__u64)(le32_to_cpu(raw_inode->i_version_hi)) << 32;
4957         }
4958
4959         ret = 0;
4960         if (ei->i_file_acl &&
4961             !ext4_data_block_valid(EXT4_SB(sb), ei->i_file_acl, 1)) {
4962                 EXT4_ERROR_INODE(inode, "bad extended attribute block %llu",
4963                                  ei->i_file_acl);
4964                 ret = -EIO;
4965                 goto bad_inode;
4966         } else if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
4967                 if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
4968                     (S_ISLNK(inode->i_mode) &&
4969                      !ext4_inode_is_fast_symlink(inode)))
4970                         /* Validate extent which is part of inode */
4971                         ret = ext4_ext_check_inode(inode);
4972         } else if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
4973                    (S_ISLNK(inode->i_mode) &&
4974                     !ext4_inode_is_fast_symlink(inode))) {
4975                 /* Validate block references which are part of inode */
4976                 ret = ext4_check_inode_blockref(inode);
4977         }
4978         if (ret)
4979                 goto bad_inode;
4980
4981         if (S_ISREG(inode->i_mode)) {
4982                 inode->i_op = &ext4_file_inode_operations;
4983                 inode->i_fop = &ext4_file_operations;
4984                 ext4_set_aops(inode);
4985         } else if (S_ISDIR(inode->i_mode)) {
4986                 inode->i_op = &ext4_dir_inode_operations;
4987                 inode->i_fop = &ext4_dir_operations;
4988         } else if (S_ISLNK(inode->i_mode)) {
4989                 if (ext4_inode_is_fast_symlink(inode)) {
4990                         inode->i_op = &ext4_fast_symlink_inode_operations;
4991                         nd_terminate_link(ei->i_data, inode->i_size,
4992                                 sizeof(ei->i_data) - 1);
4993                 } else {
4994                         inode->i_op = &ext4_symlink_inode_operations;
4995                         ext4_set_aops(inode);
4996                 }
4997         } else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
4998               S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
4999                 inode->i_op = &ext4_special_inode_operations;
5000                 if (raw_inode->i_block[0])
5001                         init_special_inode(inode, inode->i_mode,
5002                            old_decode_dev(le32_to_cpu(raw_inode->i_block[0])));
5003                 else
5004                         init_special_inode(inode, inode->i_mode,
5005                            new_decode_dev(le32_to_cpu(raw_inode->i_block[1])));
5006         } else {
5007                 ret = -EIO;
5008                 EXT4_ERROR_INODE(inode, "bogus i_mode (%o)", inode->i_mode);
5009                 goto bad_inode;
5010         }
5011         brelse(iloc.bh);
5012         ext4_set_inode_flags(inode);
5013         unlock_new_inode(inode);
5014         return inode;
5015
5016 bad_inode:
5017         brelse(iloc.bh);
5018         iget_failed(inode);
5019         return ERR_PTR(ret);
5020 }
5021
5022 static int ext4_inode_blocks_set(handle_t *handle,
5023                                 struct ext4_inode *raw_inode,
5024                                 struct ext4_inode_info *ei)
5025 {
5026         struct inode *inode = &(ei->vfs_inode);
5027         u64 i_blocks = inode->i_blocks;
5028         struct super_block *sb = inode->i_sb;
5029
5030         if (i_blocks <= ~0U) {
5031                 /*
5032                  * i_blocks can be represnted in a 32 bit variable
5033                  * as multiple of 512 bytes
5034                  */
5035                 raw_inode->i_blocks_lo   = cpu_to_le32(i_blocks);
5036                 raw_inode->i_blocks_high = 0;
5037                 ext4_clear_inode_flag(inode, EXT4_INODE_HUGE_FILE);
5038                 return 0;
5039         }
5040         if (!EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_HUGE_FILE))
5041                 return -EFBIG;
5042
5043         if (i_blocks <= 0xffffffffffffULL) {
5044                 /*
5045                  * i_blocks can be represented in a 48 bit variable
5046                  * as multiple of 512 bytes
5047                  */
5048                 raw_inode->i_blocks_lo   = cpu_to_le32(i_blocks);
5049                 raw_inode->i_blocks_high = cpu_to_le16(i_blocks >> 32);
5050                 ext4_clear_inode_flag(inode, EXT4_INODE_HUGE_FILE);
5051         } else {
5052                 ext4_set_inode_flag(inode, EXT4_INODE_HUGE_FILE);
5053                 /* i_block is stored in file system block size */
5054                 i_blocks = i_blocks >> (inode->i_blkbits - 9);
5055                 raw_inode->i_blocks_lo   = cpu_to_le32(i_blocks);
5056                 raw_inode->i_blocks_high = cpu_to_le16(i_blocks >> 32);
5057         }
5058         return 0;
5059 }
5060
5061 /*
5062  * Post the struct inode info into an on-disk inode location in the
5063  * buffer-cache.  This gobbles the caller's reference to the
5064  * buffer_head in the inode location struct.
5065  *
5066  * The caller must have write access to iloc->bh.
5067  */
5068 static int ext4_do_update_inode(handle_t *handle,
5069                                 struct inode *inode,
5070                                 struct ext4_iloc *iloc)
5071 {
5072         struct ext4_inode *raw_inode = ext4_raw_inode(iloc);
5073         struct ext4_inode_info *ei = EXT4_I(inode);
5074         struct buffer_head *bh = iloc->bh;
5075         int err = 0, rc, block;
5076
5077         /* For fields not not tracking in the in-memory inode,
5078          * initialise them to zero for new inodes. */
5079         if (ext4_test_inode_state(inode, EXT4_STATE_NEW))
5080                 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
5081
5082         ext4_get_inode_flags(ei);
5083         raw_inode->i_mode = cpu_to_le16(inode->i_mode);
5084         if (!(test_opt(inode->i_sb, NO_UID32))) {
5085                 raw_inode->i_uid_low = cpu_to_le16(low_16_bits(inode->i_uid));
5086                 raw_inode->i_gid_low = cpu_to_le16(low_16_bits(inode->i_gid));
5087 /*
5088  * Fix up interoperability with old kernels. Otherwise, old inodes get
5089  * re-used with the upper 16 bits of the uid/gid intact
5090  */
5091                 if (!ei->i_dtime) {
5092                         raw_inode->i_uid_high =
5093                                 cpu_to_le16(high_16_bits(inode->i_uid));
5094                         raw_inode->i_gid_high =
5095                                 cpu_to_le16(high_16_bits(inode->i_gid));
5096                 } else {
5097                         raw_inode->i_uid_high = 0;
5098                         raw_inode->i_gid_high = 0;
5099                 }
5100         } else {
5101                 raw_inode->i_uid_low =
5102                         cpu_to_le16(fs_high2lowuid(inode->i_uid));
5103                 raw_inode->i_gid_low =
5104                         cpu_to_le16(fs_high2lowgid(inode->i_gid));
5105                 raw_inode->i_uid_high = 0;
5106                 raw_inode->i_gid_high = 0;
5107         }
5108         raw_inode->i_links_count = cpu_to_le16(inode->i_nlink);
5109
5110         EXT4_INODE_SET_XTIME(i_ctime, inode, raw_inode);
5111         EXT4_INODE_SET_XTIME(i_mtime, inode, raw_inode);
5112         EXT4_INODE_SET_XTIME(i_atime, inode, raw_inode);
5113         EXT4_EINODE_SET_XTIME(i_crtime, ei, raw_inode);
5114
5115         if (ext4_inode_blocks_set(handle, raw_inode, ei))
5116                 goto out_brelse;
5117         raw_inode->i_dtime = cpu_to_le32(ei->i_dtime);
5118         raw_inode->i_flags = cpu_to_le32(ei->i_flags);
5119         if (EXT4_SB(inode->i_sb)->s_es->s_creator_os !=
5120             cpu_to_le32(EXT4_OS_HURD))
5121                 raw_inode->i_file_acl_high =
5122                         cpu_to_le16(ei->i_file_acl >> 32);
5123         raw_inode->i_file_acl_lo = cpu_to_le32(ei->i_file_acl);
5124         ext4_isize_set(raw_inode, ei->i_disksize);
5125         if (ei->i_disksize > 0x7fffffffULL) {
5126                 struct super_block *sb = inode->i_sb;
5127                 if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
5128                                 EXT4_FEATURE_RO_COMPAT_LARGE_FILE) ||
5129                                 EXT4_SB(sb)->s_es->s_rev_level ==
5130                                 cpu_to_le32(EXT4_GOOD_OLD_REV)) {
5131                         /* If this is the first large file
5132                          * created, add a flag to the superblock.
5133                          */
5134                         err = ext4_journal_get_write_access(handle,
5135                                         EXT4_SB(sb)->s_sbh);
5136                         if (err)
5137                                 goto out_brelse;
5138                         ext4_update_dynamic_rev(sb);
5139                         EXT4_SET_RO_COMPAT_FEATURE(sb,
5140                                         EXT4_FEATURE_RO_COMPAT_LARGE_FILE);
5141                         sb->s_dirt = 1;
5142                         ext4_handle_sync(handle);
5143                         err = ext4_handle_dirty_metadata(handle, NULL,
5144                                         EXT4_SB(sb)->s_sbh);
5145                 }
5146         }
5147         raw_inode->i_generation = cpu_to_le32(inode->i_generation);
5148         if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) {
5149                 if (old_valid_dev(inode->i_rdev)) {
5150                         raw_inode->i_block[0] =
5151                                 cpu_to_le32(old_encode_dev(inode->i_rdev));
5152                         raw_inode->i_block[1] = 0;
5153                 } else {
5154                         raw_inode->i_block[0] = 0;
5155                         raw_inode->i_block[1] =
5156                                 cpu_to_le32(new_encode_dev(inode->i_rdev));
5157                         raw_inode->i_block[2] = 0;
5158                 }
5159         } else
5160                 for (block = 0; block < EXT4_N_BLOCKS; block++)
5161                         raw_inode->i_block[block] = ei->i_data[block];
5162
5163         raw_inode->i_disk_version = cpu_to_le32(inode->i_version);
5164         if (ei->i_extra_isize) {
5165                 if (EXT4_FITS_IN_INODE(raw_inode, ei, i_version_hi))
5166                         raw_inode->i_version_hi =
5167                         cpu_to_le32(inode->i_version >> 32);
5168                 raw_inode->i_extra_isize = cpu_to_le16(ei->i_extra_isize);
5169         }
5170
5171         BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
5172         rc = ext4_handle_dirty_metadata(handle, NULL, bh);
5173         if (!err)
5174                 err = rc;
5175         ext4_clear_inode_state(inode, EXT4_STATE_NEW);
5176
5177         ext4_update_inode_fsync_trans(handle, inode, 0);
5178 out_brelse:
5179         brelse(bh);
5180         ext4_std_error(inode->i_sb, err);
5181         return err;
5182 }
5183
5184 /*
5185  * ext4_write_inode()
5186  *
5187  * We are called from a few places:
5188  *
5189  * - Within generic_file_write() for O_SYNC files.
5190  *   Here, there will be no transaction running. We wait for any running
5191  *   trasnaction to commit.
5192  *
5193  * - Within sys_sync(), kupdate and such.
5194  *   We wait on commit, if tol to.
5195  *
5196  * - Within prune_icache() (PF_MEMALLOC == true)
5197  *   Here we simply return.  We can't afford to block kswapd on the
5198  *   journal commit.
5199  *
5200  * In all cases it is actually safe for us to return without doing anything,
5201  * because the inode has been copied into a raw inode buffer in
5202  * ext4_mark_inode_dirty().  This is a correctness thing for O_SYNC and for
5203  * knfsd.
5204  *
5205  * Note that we are absolutely dependent upon all inode dirtiers doing the
5206  * right thing: they *must* call mark_inode_dirty() after dirtying info in
5207  * which we are interested.
5208  *
5209  * It would be a bug for them to not do this.  The code:
5210  *
5211  *      mark_inode_dirty(inode)
5212  *      stuff();
5213  *      inode->i_size = expr;
5214  *
5215  * is in error because a kswapd-driven write_inode() could occur while
5216  * `stuff()' is running, and the new i_size will be lost.  Plus the inode
5217  * will no longer be on the superblock's dirty inode list.
5218  */
5219 int ext4_write_inode(struct inode *inode, struct writeback_control *wbc)
5220 {
5221         int err;
5222
5223         if (current->flags & PF_MEMALLOC)
5224                 return 0;
5225
5226         if (EXT4_SB(inode->i_sb)->s_journal) {
5227                 if (ext4_journal_current_handle()) {
5228                         jbd_debug(1, "called recursively, non-PF_MEMALLOC!\n");
5229                         dump_stack();
5230                         return -EIO;
5231                 }
5232
5233                 if (wbc->sync_mode != WB_SYNC_ALL)
5234                         return 0;
5235
5236                 err = ext4_force_commit(inode->i_sb);
5237         } else {
5238                 struct ext4_iloc iloc;
5239
5240                 err = __ext4_get_inode_loc(inode, &iloc, 0);
5241                 if (err)
5242                         return err;
5243                 if (wbc->sync_mode == WB_SYNC_ALL)
5244                         sync_dirty_buffer(iloc.bh);
5245                 if (buffer_req(iloc.bh) && !buffer_uptodate(iloc.bh)) {
5246                         EXT4_ERROR_INODE_BLOCK(inode, iloc.bh->b_blocknr,
5247                                          "IO error syncing inode");
5248                         err = -EIO;
5249                 }
5250                 brelse(iloc.bh);
5251         }
5252         return err;
5253 }
5254
5255 /*
5256  * ext4_setattr()
5257  *
5258  * Called from notify_change.
5259  *
5260  * We want to trap VFS attempts to truncate the file as soon as
5261  * possible.  In particular, we want to make sure that when the VFS
5262  * shrinks i_size, we put the inode on the orphan list and modify
5263  * i_disksize immediately, so that during the subsequent flushing of
5264  * dirty pages and freeing of disk blocks, we can guarantee that any
5265  * commit will leave the blocks being flushed in an unused state on
5266  * disk.  (On recovery, the inode will get truncated and the blocks will
5267  * be freed, so we have a strong guarantee that no future commit will
5268  * leave these blocks visible to the user.)
5269  *
5270  * Another thing we have to assure is that if we are in ordered mode
5271  * and inode is still attached to the committing transaction, we must
5272  * we start writeout of all the dirty pages which are being truncated.
5273  * This way we are sure that all the data written in the previous
5274  * transaction are already on disk (truncate waits for pages under
5275  * writeback).
5276  *
5277  * Called with inode->i_mutex down.
5278  */
5279 int ext4_setattr(struct dentry *dentry, struct iattr *attr)
5280 {
5281         struct inode *inode = dentry->d_inode;
5282         int error, rc = 0;
5283         int orphan = 0;
5284         const unsigned int ia_valid = attr->ia_valid;
5285
5286         error = inode_change_ok(inode, attr);
5287         if (error)
5288                 return error;
5289
5290         if (is_quota_modification(inode, attr))
5291                 dquot_initialize(inode);
5292         if ((ia_valid & ATTR_UID && attr->ia_uid != inode->i_uid) ||
5293                 (ia_valid & ATTR_GID && attr->ia_gid != inode->i_gid)) {
5294                 handle_t *handle;
5295
5296                 /* (user+group)*(old+new) structure, inode write (sb,
5297                  * inode block, ? - but truncate inode update has it) */
5298                 handle = ext4_journal_start(inode, (EXT4_MAXQUOTAS_INIT_BLOCKS(inode->i_sb)+
5299                                         EXT4_MAXQUOTAS_DEL_BLOCKS(inode->i_sb))+3);
5300                 if (IS_ERR(handle)) {
5301                         error = PTR_ERR(handle);
5302                         goto err_out;
5303                 }
5304                 error = dquot_transfer(inode, attr);
5305                 if (error) {
5306                         ext4_journal_stop(handle);
5307                         return error;
5308                 }
5309                 /* Update corresponding info in inode so that everything is in
5310                  * one transaction */
5311                 if (attr->ia_valid & ATTR_UID)
5312                         inode->i_uid = attr->ia_uid;
5313                 if (attr->ia_valid & ATTR_GID)
5314                         inode->i_gid = attr->ia_gid;
5315                 error = ext4_mark_inode_dirty(handle, inode);
5316                 ext4_journal_stop(handle);
5317         }
5318
5319         if (attr->ia_valid & ATTR_SIZE) {
5320                 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
5321                         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
5322
5323                         if (attr->ia_size > sbi->s_bitmap_maxbytes)
5324                                 return -EFBIG;
5325                 }
5326         }
5327
5328         if (S_ISREG(inode->i_mode) &&
5329             attr->ia_valid & ATTR_SIZE &&
5330             (attr->ia_size < inode->i_size ||
5331              (ext4_test_inode_flag(inode, EXT4_INODE_EOFBLOCKS)))) {
5332                 handle_t *handle;
5333
5334                 handle = ext4_journal_start(inode, 3);
5335                 if (IS_ERR(handle)) {
5336                         error = PTR_ERR(handle);
5337                         goto err_out;
5338                 }
5339                 if (ext4_handle_valid(handle)) {
5340                         error = ext4_orphan_add(handle, inode);
5341                         orphan = 1;
5342                 }
5343                 EXT4_I(inode)->i_disksize = attr->ia_size;
5344                 rc = ext4_mark_inode_dirty(handle, inode);
5345                 if (!error)
5346                         error = rc;
5347                 ext4_journal_stop(handle);
5348
5349                 if (ext4_should_order_data(inode)) {
5350                         error = ext4_begin_ordered_truncate(inode,
5351                                                             attr->ia_size);
5352                         if (error) {
5353                                 /* Do as much error cleanup as possible */
5354                                 handle = ext4_journal_start(inode, 3);
5355                                 if (IS_ERR(handle)) {
5356                                         ext4_orphan_del(NULL, inode);
5357                                         goto err_out;
5358                                 }
5359                                 ext4_orphan_del(handle, inode);
5360                                 orphan = 0;
5361                                 ext4_journal_stop(handle);
5362                                 goto err_out;
5363                         }
5364                 }
5365                 /* ext4_truncate will clear the flag */
5366                 if ((ext4_test_inode_flag(inode, EXT4_INODE_EOFBLOCKS)))
5367                         ext4_truncate(inode);
5368         }
5369
5370         if ((attr->ia_valid & ATTR_SIZE) &&
5371             attr->ia_size != i_size_read(inode))
5372                 rc = vmtruncate(inode, attr->ia_size);
5373
5374         if (!rc) {
5375                 setattr_copy(inode, attr);
5376                 mark_inode_dirty(inode);
5377         }
5378
5379         /*
5380          * If the call to ext4_truncate failed to get a transaction handle at
5381          * all, we need to clean up the in-core orphan list manually.
5382          */
5383         if (orphan && inode->i_nlink)
5384                 ext4_orphan_del(NULL, inode);
5385
5386         if (!rc && (ia_valid & ATTR_MODE))
5387                 rc = ext4_acl_chmod(inode);
5388
5389 err_out:
5390         ext4_std_error(inode->i_sb, error);
5391         if (!error)
5392                 error = rc;
5393         return error;
5394 }
5395
5396 int ext4_getattr(struct vfsmount *mnt, struct dentry *dentry,
5397                  struct kstat *stat)
5398 {
5399         struct inode *inode;
5400         unsigned long delalloc_blocks;
5401
5402         inode = dentry->d_inode;
5403         generic_fillattr(inode, stat);
5404
5405         /*
5406          * We can't update i_blocks if the block allocation is delayed
5407          * otherwise in the case of system crash before the real block
5408          * allocation is done, we will have i_blocks inconsistent with
5409          * on-disk file blocks.
5410          * We always keep i_blocks updated together with real
5411          * allocation. But to not confuse with user, stat
5412          * will return the blocks that include the delayed allocation
5413          * blocks for this file.
5414          */
5415         delalloc_blocks = EXT4_I(inode)->i_reserved_data_blocks;
5416
5417         stat->blocks += (delalloc_blocks << inode->i_sb->s_blocksize_bits)>>9;
5418         return 0;
5419 }
5420
5421 static int ext4_indirect_trans_blocks(struct inode *inode, int nrblocks,
5422                                       int chunk)
5423 {
5424         int indirects;
5425
5426         /* if nrblocks are contiguous */
5427         if (chunk) {
5428                 /*
5429                  * With N contiguous data blocks, it need at most
5430                  * N/EXT4_ADDR_PER_BLOCK(inode->i_sb) indirect blocks
5431                  * 2 dindirect blocks
5432                  * 1 tindirect block
5433                  */
5434                 indirects = nrblocks / EXT4_ADDR_PER_BLOCK(inode->i_sb);
5435                 return indirects + 3;
5436         }
5437         /*
5438          * if nrblocks are not contiguous, worse case, each block touch
5439          * a indirect block, and each indirect block touch a double indirect
5440          * block, plus a triple indirect block
5441          */
5442         indirects = nrblocks * 2 + 1;
5443         return indirects;
5444 }
5445
5446 static int ext4_index_trans_blocks(struct inode *inode, int nrblocks, int chunk)
5447 {
5448         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
5449                 return ext4_indirect_trans_blocks(inode, nrblocks, chunk);
5450         return ext4_ext_index_trans_blocks(inode, nrblocks, chunk);
5451 }
5452
5453 /*
5454  * Account for index blocks, block groups bitmaps and block group
5455  * descriptor blocks if modify datablocks and index blocks
5456  * worse case, the indexs blocks spread over different block groups
5457  *
5458  * If datablocks are discontiguous, they are possible to spread over
5459  * different block groups too. If they are contiuguous, with flexbg,
5460  * they could still across block group boundary.
5461  *
5462  * Also account for superblock, inode, quota and xattr blocks
5463  */
5464 static int ext4_meta_trans_blocks(struct inode *inode, int nrblocks, int chunk)
5465 {
5466         ext4_group_t groups, ngroups = ext4_get_groups_count(inode->i_sb);
5467         int gdpblocks;
5468         int idxblocks;
5469         int ret = 0;
5470
5471         /*
5472          * How many index blocks need to touch to modify nrblocks?
5473          * The "Chunk" flag indicating whether the nrblocks is
5474          * physically contiguous on disk
5475          *
5476          * For Direct IO and fallocate, they calls get_block to allocate
5477          * one single extent at a time, so they could set the "Chunk" flag
5478          */
5479         idxblocks = ext4_index_trans_blocks(inode, nrblocks, chunk);
5480
5481         ret = idxblocks;
5482
5483         /*
5484          * Now let's see how many group bitmaps and group descriptors need
5485          * to account
5486          */
5487         groups = idxblocks;
5488         if (chunk)
5489                 groups += 1;
5490         else
5491                 groups += nrblocks;
5492
5493         gdpblocks = groups;
5494         if (groups > ngroups)
5495                 groups = ngroups;
5496         if (groups > EXT4_SB(inode->i_sb)->s_gdb_count)
5497                 gdpblocks = EXT4_SB(inode->i_sb)->s_gdb_count;
5498
5499         /* bitmaps and block group descriptor blocks */
5500         ret += groups + gdpblocks;
5501
5502         /* Blocks for super block, inode, quota and xattr blocks */
5503         ret += EXT4_META_TRANS_BLOCKS(inode->i_sb);
5504
5505         return ret;
5506 }
5507
5508 /*
5509  * Calulate the total number of credits to reserve to fit
5510  * the modification of a single pages into a single transaction,
5511  * which may include multiple chunks of block allocations.
5512  *
5513  * This could be called via ext4_write_begin()
5514  *
5515  * We need to consider the worse case, when
5516  * one new block per extent.
5517  */
5518 int ext4_writepage_trans_blocks(struct inode *inode)
5519 {
5520         int bpp = ext4_journal_blocks_per_page(inode);
5521         int ret;
5522
5523         ret = ext4_meta_trans_blocks(inode, bpp, 0);
5524
5525         /* Account for data blocks for journalled mode */
5526         if (ext4_should_journal_data(inode))
5527                 ret += bpp;
5528         return ret;
5529 }
5530
5531 /*
5532  * Calculate the journal credits for a chunk of data modification.
5533  *
5534  * This is called from DIO, fallocate or whoever calling
5535  * ext4_map_blocks() to map/allocate a chunk of contiguous disk blocks.
5536  *
5537  * journal buffers for data blocks are not included here, as DIO
5538  * and fallocate do no need to journal data buffers.
5539  */
5540 int ext4_chunk_trans_blocks(struct inode *inode, int nrblocks)
5541 {
5542         return ext4_meta_trans_blocks(inode, nrblocks, 1);
5543 }
5544
5545 /*
5546  * The caller must have previously called ext4_reserve_inode_write().
5547  * Give this, we know that the caller already has write access to iloc->bh.
5548  */
5549 int ext4_mark_iloc_dirty(handle_t *handle,
5550                          struct inode *inode, struct ext4_iloc *iloc)
5551 {
5552         int err = 0;
5553
5554         if (test_opt(inode->i_sb, I_VERSION))
5555                 inode_inc_iversion(inode);
5556
5557         /* the do_update_inode consumes one bh->b_count */
5558         get_bh(iloc->bh);
5559
5560         /* ext4_do_update_inode() does jbd2_journal_dirty_metadata */
5561         err = ext4_do_update_inode(handle, inode, iloc);
5562         put_bh(iloc->bh);
5563         return err;
5564 }
5565
5566 /*
5567  * On success, We end up with an outstanding reference count against
5568  * iloc->bh.  This _must_ be cleaned up later.
5569  */
5570
5571 int
5572 ext4_reserve_inode_write(handle_t *handle, struct inode *inode,
5573                          struct ext4_iloc *iloc)
5574 {
5575         int err;
5576
5577         err = ext4_get_inode_loc(inode, iloc);
5578         if (!err) {
5579                 BUFFER_TRACE(iloc->bh, "get_write_access");
5580                 err = ext4_journal_get_write_access(handle, iloc->bh);
5581                 if (err) {
5582                         brelse(iloc->bh);
5583                         iloc->bh = NULL;
5584                 }
5585         }
5586         ext4_std_error(inode->i_sb, err);
5587         return err;
5588 }
5589
5590 /*
5591  * Expand an inode by new_extra_isize bytes.
5592  * Returns 0 on success or negative error number on failure.
5593  */
5594 static int ext4_expand_extra_isize(struct inode *inode,
5595                                    unsigned int new_extra_isize,
5596                                    struct ext4_iloc iloc,
5597                                    handle_t *handle)
5598 {
5599         struct ext4_inode *raw_inode;
5600         struct ext4_xattr_ibody_header *header;
5601
5602         if (EXT4_I(inode)->i_extra_isize >= new_extra_isize)
5603                 return 0;
5604
5605         raw_inode = ext4_raw_inode(&iloc);
5606
5607         header = IHDR(inode, raw_inode);
5608
5609         /* No extended attributes present */
5610         if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR) ||
5611             header->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC)) {
5612                 memset((void *)raw_inode + EXT4_GOOD_OLD_INODE_SIZE, 0,
5613                         new_extra_isize);
5614                 EXT4_I(inode)->i_extra_isize = new_extra_isize;
5615                 return 0;
5616         }
5617
5618         /* try to expand with EAs present */
5619         return ext4_expand_extra_isize_ea(inode, new_extra_isize,
5620                                           raw_inode, handle);
5621 }
5622
5623 /*
5624  * What we do here is to mark the in-core inode as clean with respect to inode
5625  * dirtiness (it may still be data-dirty).
5626  * This means that the in-core inode may be reaped by prune_icache
5627  * without having to perform any I/O.  This is a very good thing,
5628  * because *any* task may call prune_icache - even ones which
5629  * have a transaction open against a different journal.
5630  *
5631  * Is this cheating?  Not really.  Sure, we haven't written the
5632  * inode out, but prune_icache isn't a user-visible syncing function.
5633  * Whenever the user wants stuff synced (sys_sync, sys_msync, sys_fsync)
5634  * we start and wait on commits.
5635  *
5636  * Is this efficient/effective?  Well, we're being nice to the system
5637  * by cleaning up our inodes proactively so they can be reaped
5638  * without I/O.  But we are potentially leaving up to five seconds'
5639  * worth of inodes floating about which prune_icache wants us to
5640  * write out.  One way to fix that would be to get prune_icache()
5641  * to do a write_super() to free up some memory.  It has the desired
5642  * effect.
5643  */
5644 int ext4_mark_inode_dirty(handle_t *handle, struct inode *inode)
5645 {
5646         struct ext4_iloc iloc;
5647         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
5648         static unsigned int mnt_count;
5649         int err, ret;
5650
5651         might_sleep();
5652         trace_ext4_mark_inode_dirty(inode, _RET_IP_);
5653         err = ext4_reserve_inode_write(handle, inode, &iloc);
5654         if (ext4_handle_valid(handle) &&
5655             EXT4_I(inode)->i_extra_isize < sbi->s_want_extra_isize &&
5656             !ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND)) {
5657                 /*
5658                  * We need extra buffer credits since we may write into EA block
5659                  * with this same handle. If journal_extend fails, then it will
5660                  * only result in a minor loss of functionality for that inode.
5661                  * If this is felt to be critical, then e2fsck should be run to
5662                  * force a large enough s_min_extra_isize.
5663                  */
5664                 if ((jbd2_journal_extend(handle,
5665                              EXT4_DATA_TRANS_BLOCKS(inode->i_sb))) == 0) {
5666                         ret = ext4_expand_extra_isize(inode,
5667                                                       sbi->s_want_extra_isize,
5668                                                       iloc, handle);
5669                         if (ret) {
5670                                 ext4_set_inode_state(inode,
5671                                                      EXT4_STATE_NO_EXPAND);
5672                                 if (mnt_count !=
5673                                         le16_to_cpu(sbi->s_es->s_mnt_count)) {
5674                                         ext4_warning(inode->i_sb,
5675                                         "Unable to expand inode %lu. Delete"
5676                                         " some EAs or run e2fsck.",
5677                                         inode->i_ino);
5678                                         mnt_count =
5679                                           le16_to_cpu(sbi->s_es->s_mnt_count);
5680                                 }
5681                         }
5682                 }
5683         }
5684         if (!err)
5685                 err = ext4_mark_iloc_dirty(handle, inode, &iloc);
5686         return err;
5687 }
5688
5689 /*
5690  * ext4_dirty_inode() is called from __mark_inode_dirty()
5691  *
5692  * We're really interested in the case where a file is being extended.
5693  * i_size has been changed by generic_commit_write() and we thus need
5694  * to include the updated inode in the current transaction.
5695  *
5696  * Also, dquot_alloc_block() will always dirty the inode when blocks
5697  * are allocated to the file.
5698  *
5699  * If the inode is marked synchronous, we don't honour that here - doing
5700  * so would cause a commit on atime updates, which we don't bother doing.
5701  * We handle synchronous inodes at the highest possible level.
5702  */
5703 void ext4_dirty_inode(struct inode *inode)
5704 {
5705         handle_t *handle;
5706
5707         handle = ext4_journal_start(inode, 2);
5708         if (IS_ERR(handle))
5709                 goto out;
5710
5711         ext4_mark_inode_dirty(handle, inode);
5712
5713         ext4_journal_stop(handle);
5714 out:
5715         return;
5716 }
5717
5718 #if 0
5719 /*
5720  * Bind an inode's backing buffer_head into this transaction, to prevent
5721  * it from being flushed to disk early.  Unlike
5722  * ext4_reserve_inode_write, this leaves behind no bh reference and
5723  * returns no iloc structure, so the caller needs to repeat the iloc
5724  * lookup to mark the inode dirty later.
5725  */
5726 static int ext4_pin_inode(handle_t *handle, struct inode *inode)
5727 {
5728         struct ext4_iloc iloc;
5729
5730         int err = 0;
5731         if (handle) {
5732                 err = ext4_get_inode_loc(inode, &iloc);
5733                 if (!err) {
5734                         BUFFER_TRACE(iloc.bh, "get_write_access");
5735                         err = jbd2_journal_get_write_access(handle, iloc.bh);
5736                         if (!err)
5737                                 err = ext4_handle_dirty_metadata(handle,
5738                                                                  NULL,
5739                                                                  iloc.bh);
5740                         brelse(iloc.bh);
5741                 }
5742         }
5743         ext4_std_error(inode->i_sb, err);
5744         return err;
5745 }
5746 #endif
5747
5748 int ext4_change_inode_journal_flag(struct inode *inode, int val)
5749 {
5750         journal_t *journal;
5751         handle_t *handle;
5752         int err;
5753
5754         /*
5755          * We have to be very careful here: changing a data block's
5756          * journaling status dynamically is dangerous.  If we write a
5757          * data block to the journal, change the status and then delete
5758          * that block, we risk forgetting to revoke the old log record
5759          * from the journal and so a subsequent replay can corrupt data.
5760          * So, first we make sure that the journal is empty and that
5761          * nobody is changing anything.
5762          */
5763
5764         journal = EXT4_JOURNAL(inode);
5765         if (!journal)
5766                 return 0;
5767         if (is_journal_aborted(journal))
5768                 return -EROFS;
5769
5770         jbd2_journal_lock_updates(journal);
5771         jbd2_journal_flush(journal);
5772
5773         /*
5774          * OK, there are no updates running now, and all cached data is
5775          * synced to disk.  We are now in a completely consistent state
5776          * which doesn't have anything in the journal, and we know that
5777          * no filesystem updates are running, so it is safe to modify
5778          * the inode's in-core data-journaling state flag now.
5779          */
5780
5781         if (val)
5782                 ext4_set_inode_flag(inode, EXT4_INODE_JOURNAL_DATA);
5783         else
5784                 ext4_clear_inode_flag(inode, EXT4_INODE_JOURNAL_DATA);
5785         ext4_set_aops(inode);
5786
5787         jbd2_journal_unlock_updates(journal);
5788
5789         /* Finally we can mark the inode as dirty. */
5790
5791         handle = ext4_journal_start(inode, 1);
5792         if (IS_ERR(handle))
5793                 return PTR_ERR(handle);
5794
5795         err = ext4_mark_inode_dirty(handle, inode);
5796         ext4_handle_sync(handle);
5797         ext4_journal_stop(handle);
5798         ext4_std_error(inode->i_sb, err);
5799
5800         return err;
5801 }
5802
5803 static int ext4_bh_unmapped(handle_t *handle, struct buffer_head *bh)
5804 {
5805         return !buffer_mapped(bh);
5806 }
5807
5808 int ext4_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
5809 {
5810         struct page *page = vmf->page;
5811         loff_t size;
5812         unsigned long len;
5813         int ret = -EINVAL;
5814         void *fsdata;
5815         struct file *file = vma->vm_file;
5816         struct inode *inode = file->f_path.dentry->d_inode;
5817         struct address_space *mapping = inode->i_mapping;
5818
5819         /*
5820          * Get i_alloc_sem to stop truncates messing with the inode. We cannot
5821          * get i_mutex because we are already holding mmap_sem.
5822          */
5823         down_read(&inode->i_alloc_sem);
5824         size = i_size_read(inode);
5825         if (page->mapping != mapping || size <= page_offset(page)
5826             || !PageUptodate(page)) {
5827                 /* page got truncated from under us? */
5828                 goto out_unlock;
5829         }
5830         ret = 0;
5831         if (PageMappedToDisk(page))
5832                 goto out_unlock;
5833
5834         if (page->index == size >> PAGE_CACHE_SHIFT)
5835                 len = size & ~PAGE_CACHE_MASK;
5836         else
5837                 len = PAGE_CACHE_SIZE;
5838
5839         lock_page(page);
5840         /*
5841          * return if we have all the buffers mapped. This avoid
5842          * the need to call write_begin/write_end which does a
5843          * journal_start/journal_stop which can block and take
5844          * long time
5845          */
5846         if (page_has_buffers(page)) {
5847                 if (!walk_page_buffers(NULL, page_buffers(page), 0, len, NULL,
5848                                         ext4_bh_unmapped)) {
5849                         unlock_page(page);
5850                         goto out_unlock;
5851                 }
5852         }
5853         unlock_page(page);
5854         /*
5855          * OK, we need to fill the hole... Do write_begin write_end
5856          * to do block allocation/reservation.We are not holding
5857          * inode.i__mutex here. That allow * parallel write_begin,
5858          * write_end call. lock_page prevent this from happening
5859          * on the same page though
5860          */
5861         ret = mapping->a_ops->write_begin(file, mapping, page_offset(page),
5862                         len, AOP_FLAG_UNINTERRUPTIBLE, &page, &fsdata);
5863         if (ret < 0)
5864                 goto out_unlock;
5865         ret = mapping->a_ops->write_end(file, mapping, page_offset(page),
5866                         len, len, page, fsdata);
5867         if (ret < 0)
5868                 goto out_unlock;
5869         ret = 0;
5870 out_unlock:
5871         if (ret)
5872                 ret = VM_FAULT_SIGBUS;
5873         up_read(&inode->i_alloc_sem);
5874         return ret;
5875 }