29ed682061f6453341c48a0c0f5aab34ac42cd89
[pandora-kernel.git] / fs / ext2 / inode.c
1 /*
2  *  linux/fs/ext2/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@dcs.ed.ac.uk), 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 ext2_get_block() by Al Viro, 2000
23  */
24
25 #include <linux/smp_lock.h>
26 #include <linux/time.h>
27 #include <linux/highuid.h>
28 #include <linux/pagemap.h>
29 #include <linux/quotaops.h>
30 #include <linux/module.h>
31 #include <linux/writeback.h>
32 #include <linux/buffer_head.h>
33 #include <linux/mpage.h>
34 #include <linux/fiemap.h>
35 #include <linux/namei.h>
36 #include "ext2.h"
37 #include "acl.h"
38 #include "xip.h"
39
40 MODULE_AUTHOR("Remy Card and others");
41 MODULE_DESCRIPTION("Second Extended Filesystem");
42 MODULE_LICENSE("GPL");
43
44 /*
45  * Test whether an inode is a fast symlink.
46  */
47 static inline int ext2_inode_is_fast_symlink(struct inode *inode)
48 {
49         int ea_blocks = EXT2_I(inode)->i_file_acl ?
50                 (inode->i_sb->s_blocksize >> 9) : 0;
51
52         return (S_ISLNK(inode->i_mode) &&
53                 inode->i_blocks - ea_blocks == 0);
54 }
55
56 /*
57  * Called at the last iput() if i_nlink is zero.
58  */
59 void ext2_delete_inode (struct inode * inode)
60 {
61         truncate_inode_pages(&inode->i_data, 0);
62
63         if (is_bad_inode(inode))
64                 goto no_delete;
65         EXT2_I(inode)->i_dtime  = get_seconds();
66         mark_inode_dirty(inode);
67         ext2_write_inode(inode, inode_needs_sync(inode));
68
69         inode->i_size = 0;
70         if (inode->i_blocks)
71                 ext2_truncate (inode);
72         ext2_free_inode (inode);
73
74         return;
75 no_delete:
76         clear_inode(inode);     /* We must guarantee clearing of inode... */
77 }
78
79 typedef struct {
80         __le32  *p;
81         __le32  key;
82         struct buffer_head *bh;
83 } Indirect;
84
85 static inline void add_chain(Indirect *p, struct buffer_head *bh, __le32 *v)
86 {
87         p->key = *(p->p = v);
88         p->bh = bh;
89 }
90
91 static inline int verify_chain(Indirect *from, Indirect *to)
92 {
93         while (from <= to && from->key == *from->p)
94                 from++;
95         return (from > to);
96 }
97
98 /**
99  *      ext2_block_to_path - parse the block number into array of offsets
100  *      @inode: inode in question (we are only interested in its superblock)
101  *      @i_block: block number to be parsed
102  *      @offsets: array to store the offsets in
103  *      @boundary: set this non-zero if the referred-to block is likely to be
104  *             followed (on disk) by an indirect block.
105  *      To store the locations of file's data ext2 uses a data structure common
106  *      for UNIX filesystems - tree of pointers anchored in the inode, with
107  *      data blocks at leaves and indirect blocks in intermediate nodes.
108  *      This function translates the block number into path in that tree -
109  *      return value is the path length and @offsets[n] is the offset of
110  *      pointer to (n+1)th node in the nth one. If @block is out of range
111  *      (negative or too large) warning is printed and zero returned.
112  *
113  *      Note: function doesn't find node addresses, so no IO is needed. All
114  *      we need to know is the capacity of indirect blocks (taken from the
115  *      inode->i_sb).
116  */
117
118 /*
119  * Portability note: the last comparison (check that we fit into triple
120  * indirect block) is spelled differently, because otherwise on an
121  * architecture with 32-bit longs and 8Kb pages we might get into trouble
122  * if our filesystem had 8Kb blocks. We might use long long, but that would
123  * kill us on x86. Oh, well, at least the sign propagation does not matter -
124  * i_block would have to be negative in the very beginning, so we would not
125  * get there at all.
126  */
127
128 static int ext2_block_to_path(struct inode *inode,
129                         long i_block, int offsets[4], int *boundary)
130 {
131         int ptrs = EXT2_ADDR_PER_BLOCK(inode->i_sb);
132         int ptrs_bits = EXT2_ADDR_PER_BLOCK_BITS(inode->i_sb);
133         const long direct_blocks = EXT2_NDIR_BLOCKS,
134                 indirect_blocks = ptrs,
135                 double_blocks = (1 << (ptrs_bits * 2));
136         int n = 0;
137         int final = 0;
138
139         if (i_block < 0) {
140                 ext2_warning (inode->i_sb, "ext2_block_to_path", "block < 0");
141         } else if (i_block < direct_blocks) {
142                 offsets[n++] = i_block;
143                 final = direct_blocks;
144         } else if ( (i_block -= direct_blocks) < indirect_blocks) {
145                 offsets[n++] = EXT2_IND_BLOCK;
146                 offsets[n++] = i_block;
147                 final = ptrs;
148         } else if ((i_block -= indirect_blocks) < double_blocks) {
149                 offsets[n++] = EXT2_DIND_BLOCK;
150                 offsets[n++] = i_block >> ptrs_bits;
151                 offsets[n++] = i_block & (ptrs - 1);
152                 final = ptrs;
153         } else if (((i_block -= double_blocks) >> (ptrs_bits * 2)) < ptrs) {
154                 offsets[n++] = EXT2_TIND_BLOCK;
155                 offsets[n++] = i_block >> (ptrs_bits * 2);
156                 offsets[n++] = (i_block >> ptrs_bits) & (ptrs - 1);
157                 offsets[n++] = i_block & (ptrs - 1);
158                 final = ptrs;
159         } else {
160                 ext2_warning (inode->i_sb, "ext2_block_to_path", "block > big");
161         }
162         if (boundary)
163                 *boundary = final - 1 - (i_block & (ptrs - 1));
164
165         return n;
166 }
167
168 /**
169  *      ext2_get_branch - read the chain of indirect blocks leading to data
170  *      @inode: inode in question
171  *      @depth: depth of the chain (1 - direct pointer, etc.)
172  *      @offsets: offsets of pointers in inode/indirect blocks
173  *      @chain: place to store the result
174  *      @err: here we store the error value
175  *
176  *      Function fills the array of triples <key, p, bh> and returns %NULL
177  *      if everything went OK or the pointer to the last filled triple
178  *      (incomplete one) otherwise. Upon the return chain[i].key contains
179  *      the number of (i+1)-th block in the chain (as it is stored in memory,
180  *      i.e. little-endian 32-bit), chain[i].p contains the address of that
181  *      number (it points into struct inode for i==0 and into the bh->b_data
182  *      for i>0) and chain[i].bh points to the buffer_head of i-th indirect
183  *      block for i>0 and NULL for i==0. In other words, it holds the block
184  *      numbers of the chain, addresses they were taken from (and where we can
185  *      verify that chain did not change) and buffer_heads hosting these
186  *      numbers.
187  *
188  *      Function stops when it stumbles upon zero pointer (absent block)
189  *              (pointer to last triple returned, *@err == 0)
190  *      or when it gets an IO error reading an indirect block
191  *              (ditto, *@err == -EIO)
192  *      or when it notices that chain had been changed while it was reading
193  *              (ditto, *@err == -EAGAIN)
194  *      or when it reads all @depth-1 indirect blocks successfully and finds
195  *      the whole chain, all way to the data (returns %NULL, *err == 0).
196  */
197 static Indirect *ext2_get_branch(struct inode *inode,
198                                  int depth,
199                                  int *offsets,
200                                  Indirect chain[4],
201                                  int *err)
202 {
203         struct super_block *sb = inode->i_sb;
204         Indirect *p = chain;
205         struct buffer_head *bh;
206
207         *err = 0;
208         /* i_data is not going away, no lock needed */
209         add_chain (chain, NULL, EXT2_I(inode)->i_data + *offsets);
210         if (!p->key)
211                 goto no_block;
212         while (--depth) {
213                 bh = sb_bread(sb, le32_to_cpu(p->key));
214                 if (!bh)
215                         goto failure;
216                 read_lock(&EXT2_I(inode)->i_meta_lock);
217                 if (!verify_chain(chain, p))
218                         goto changed;
219                 add_chain(++p, bh, (__le32*)bh->b_data + *++offsets);
220                 read_unlock(&EXT2_I(inode)->i_meta_lock);
221                 if (!p->key)
222                         goto no_block;
223         }
224         return NULL;
225
226 changed:
227         read_unlock(&EXT2_I(inode)->i_meta_lock);
228         brelse(bh);
229         *err = -EAGAIN;
230         goto no_block;
231 failure:
232         *err = -EIO;
233 no_block:
234         return p;
235 }
236
237 /**
238  *      ext2_find_near - find a place for allocation with sufficient locality
239  *      @inode: owner
240  *      @ind: descriptor of indirect block.
241  *
242  *      This function returns the preferred place for block allocation.
243  *      It is used when heuristic for sequential allocation fails.
244  *      Rules are:
245  *        + if there is a block to the left of our position - allocate near it.
246  *        + if pointer will live in indirect block - allocate near that block.
247  *        + if pointer will live in inode - allocate in the same cylinder group.
248  *
249  * In the latter case we colour the starting block by the callers PID to
250  * prevent it from clashing with concurrent allocations for a different inode
251  * in the same block group.   The PID is used here so that functionally related
252  * files will be close-by on-disk.
253  *
254  *      Caller must make sure that @ind is valid and will stay that way.
255  */
256
257 static ext2_fsblk_t ext2_find_near(struct inode *inode, Indirect *ind)
258 {
259         struct ext2_inode_info *ei = EXT2_I(inode);
260         __le32 *start = ind->bh ? (__le32 *) ind->bh->b_data : ei->i_data;
261         __le32 *p;
262         ext2_fsblk_t bg_start;
263         ext2_fsblk_t colour;
264
265         /* Try to find previous block */
266         for (p = ind->p - 1; p >= start; p--)
267                 if (*p)
268                         return le32_to_cpu(*p);
269
270         /* No such thing, so let's try location of indirect block */
271         if (ind->bh)
272                 return ind->bh->b_blocknr;
273
274         /*
275          * It is going to be refered from inode itself? OK, just put it into
276          * the same cylinder group then.
277          */
278         bg_start = ext2_group_first_block_no(inode->i_sb, ei->i_block_group);
279         colour = (current->pid % 16) *
280                         (EXT2_BLOCKS_PER_GROUP(inode->i_sb) / 16);
281         return bg_start + colour;
282 }
283
284 /**
285  *      ext2_find_goal - find a preferred place for allocation.
286  *      @inode: owner
287  *      @block:  block we want
288  *      @partial: pointer to the last triple within a chain
289  *
290  *      Returns preferred place for a block (the goal).
291  */
292
293 static inline ext2_fsblk_t ext2_find_goal(struct inode *inode, long block,
294                                           Indirect *partial)
295 {
296         struct ext2_block_alloc_info *block_i;
297
298         block_i = EXT2_I(inode)->i_block_alloc_info;
299
300         /*
301          * try the heuristic for sequential allocation,
302          * failing that at least try to get decent locality.
303          */
304         if (block_i && (block == block_i->last_alloc_logical_block + 1)
305                 && (block_i->last_alloc_physical_block != 0)) {
306                 return block_i->last_alloc_physical_block + 1;
307         }
308
309         return ext2_find_near(inode, partial);
310 }
311
312 /**
313  *      ext2_blks_to_allocate: Look up the block map and count the number
314  *      of direct blocks need to be allocated for the given branch.
315  *
316  *      @branch: chain of indirect blocks
317  *      @k: number of blocks need for indirect blocks
318  *      @blks: number of data blocks to be mapped.
319  *      @blocks_to_boundary:  the offset in the indirect block
320  *
321  *      return the total number of blocks to be allocate, including the
322  *      direct and indirect blocks.
323  */
324 static int
325 ext2_blks_to_allocate(Indirect * branch, int k, unsigned long blks,
326                 int blocks_to_boundary)
327 {
328         unsigned long count = 0;
329
330         /*
331          * Simple case, [t,d]Indirect block(s) has not allocated yet
332          * then it's clear blocks on that path have not allocated
333          */
334         if (k > 0) {
335                 /* right now don't hanel cross boundary allocation */
336                 if (blks < blocks_to_boundary + 1)
337                         count += blks;
338                 else
339                         count += blocks_to_boundary + 1;
340                 return count;
341         }
342
343         count++;
344         while (count < blks && count <= blocks_to_boundary
345                 && le32_to_cpu(*(branch[0].p + count)) == 0) {
346                 count++;
347         }
348         return count;
349 }
350
351 /**
352  *      ext2_alloc_blocks: multiple allocate blocks needed for a branch
353  *      @indirect_blks: the number of blocks need to allocate for indirect
354  *                      blocks
355  *
356  *      @new_blocks: on return it will store the new block numbers for
357  *      the indirect blocks(if needed) and the first direct block,
358  *      @blks:  on return it will store the total number of allocated
359  *              direct blocks
360  */
361 static int ext2_alloc_blocks(struct inode *inode,
362                         ext2_fsblk_t goal, int indirect_blks, int blks,
363                         ext2_fsblk_t new_blocks[4], int *err)
364 {
365         int target, i;
366         unsigned long count = 0;
367         int index = 0;
368         ext2_fsblk_t current_block = 0;
369         int ret = 0;
370
371         /*
372          * Here we try to allocate the requested multiple blocks at once,
373          * on a best-effort basis.
374          * To build a branch, we should allocate blocks for
375          * the indirect blocks(if not allocated yet), and at least
376          * the first direct block of this branch.  That's the
377          * minimum number of blocks need to allocate(required)
378          */
379         target = blks + indirect_blks;
380
381         while (1) {
382                 count = target;
383                 /* allocating blocks for indirect blocks and direct blocks */
384                 current_block = ext2_new_blocks(inode,goal,&count,err);
385                 if (*err)
386                         goto failed_out;
387
388                 target -= count;
389                 /* allocate blocks for indirect blocks */
390                 while (index < indirect_blks && count) {
391                         new_blocks[index++] = current_block++;
392                         count--;
393                 }
394
395                 if (count > 0)
396                         break;
397         }
398
399         /* save the new block number for the first direct block */
400         new_blocks[index] = current_block;
401
402         /* total number of blocks allocated for direct blocks */
403         ret = count;
404         *err = 0;
405         return ret;
406 failed_out:
407         for (i = 0; i <index; i++)
408                 ext2_free_blocks(inode, new_blocks[i], 1);
409         return ret;
410 }
411
412 /**
413  *      ext2_alloc_branch - allocate and set up a chain of blocks.
414  *      @inode: owner
415  *      @num: depth of the chain (number of blocks to allocate)
416  *      @offsets: offsets (in the blocks) to store the pointers to next.
417  *      @branch: place to store the chain in.
418  *
419  *      This function allocates @num blocks, zeroes out all but the last one,
420  *      links them into chain and (if we are synchronous) writes them to disk.
421  *      In other words, it prepares a branch that can be spliced onto the
422  *      inode. It stores the information about that chain in the branch[], in
423  *      the same format as ext2_get_branch() would do. We are calling it after
424  *      we had read the existing part of chain and partial points to the last
425  *      triple of that (one with zero ->key). Upon the exit we have the same
426  *      picture as after the successful ext2_get_block(), excpet that in one
427  *      place chain is disconnected - *branch->p is still zero (we did not
428  *      set the last link), but branch->key contains the number that should
429  *      be placed into *branch->p to fill that gap.
430  *
431  *      If allocation fails we free all blocks we've allocated (and forget
432  *      their buffer_heads) and return the error value the from failed
433  *      ext2_alloc_block() (normally -ENOSPC). Otherwise we set the chain
434  *      as described above and return 0.
435  */
436
437 static int ext2_alloc_branch(struct inode *inode,
438                         int indirect_blks, int *blks, ext2_fsblk_t goal,
439                         int *offsets, Indirect *branch)
440 {
441         int blocksize = inode->i_sb->s_blocksize;
442         int i, n = 0;
443         int err = 0;
444         struct buffer_head *bh;
445         int num;
446         ext2_fsblk_t new_blocks[4];
447         ext2_fsblk_t current_block;
448
449         num = ext2_alloc_blocks(inode, goal, indirect_blks,
450                                 *blks, new_blocks, &err);
451         if (err)
452                 return err;
453
454         branch[0].key = cpu_to_le32(new_blocks[0]);
455         /*
456          * metadata blocks and data blocks are allocated.
457          */
458         for (n = 1; n <= indirect_blks;  n++) {
459                 /*
460                  * Get buffer_head for parent block, zero it out
461                  * and set the pointer to new one, then send
462                  * parent to disk.
463                  */
464                 bh = sb_getblk(inode->i_sb, new_blocks[n-1]);
465                 branch[n].bh = bh;
466                 lock_buffer(bh);
467                 memset(bh->b_data, 0, blocksize);
468                 branch[n].p = (__le32 *) bh->b_data + offsets[n];
469                 branch[n].key = cpu_to_le32(new_blocks[n]);
470                 *branch[n].p = branch[n].key;
471                 if ( n == indirect_blks) {
472                         current_block = new_blocks[n];
473                         /*
474                          * End of chain, update the last new metablock of
475                          * the chain to point to the new allocated
476                          * data blocks numbers
477                          */
478                         for (i=1; i < num; i++)
479                                 *(branch[n].p + i) = cpu_to_le32(++current_block);
480                 }
481                 set_buffer_uptodate(bh);
482                 unlock_buffer(bh);
483                 mark_buffer_dirty_inode(bh, inode);
484                 /* We used to sync bh here if IS_SYNC(inode).
485                  * But we now rely upon generic_osync_inode()
486                  * and b_inode_buffers.  But not for directories.
487                  */
488                 if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode))
489                         sync_dirty_buffer(bh);
490         }
491         *blks = num;
492         return err;
493 }
494
495 /**
496  * ext2_splice_branch - splice the allocated branch onto inode.
497  * @inode: owner
498  * @block: (logical) number of block we are adding
499  * @where: location of missing link
500  * @num:   number of indirect blocks we are adding
501  * @blks:  number of direct blocks we are adding
502  *
503  * This function fills the missing link and does all housekeeping needed in
504  * inode (->i_blocks, etc.). In case of success we end up with the full
505  * chain to new block and return 0.
506  */
507 static void ext2_splice_branch(struct inode *inode,
508                         long block, Indirect *where, int num, int blks)
509 {
510         int i;
511         struct ext2_block_alloc_info *block_i;
512         ext2_fsblk_t current_block;
513
514         block_i = EXT2_I(inode)->i_block_alloc_info;
515
516         /* XXX LOCKING probably should have i_meta_lock ?*/
517         /* That's it */
518
519         *where->p = where->key;
520
521         /*
522          * Update the host buffer_head or inode to point to more just allocated
523          * direct blocks blocks
524          */
525         if (num == 0 && blks > 1) {
526                 current_block = le32_to_cpu(where->key) + 1;
527                 for (i = 1; i < blks; i++)
528                         *(where->p + i ) = cpu_to_le32(current_block++);
529         }
530
531         /*
532          * update the most recently allocated logical & physical block
533          * in i_block_alloc_info, to assist find the proper goal block for next
534          * allocation
535          */
536         if (block_i) {
537                 block_i->last_alloc_logical_block = block + blks - 1;
538                 block_i->last_alloc_physical_block =
539                                 le32_to_cpu(where[num].key) + blks - 1;
540         }
541
542         /* We are done with atomic stuff, now do the rest of housekeeping */
543
544         /* had we spliced it onto indirect block? */
545         if (where->bh)
546                 mark_buffer_dirty_inode(where->bh, inode);
547
548         inode->i_ctime = CURRENT_TIME_SEC;
549         mark_inode_dirty(inode);
550 }
551
552 /*
553  * Allocation strategy is simple: if we have to allocate something, we will
554  * have to go the whole way to leaf. So let's do it before attaching anything
555  * to tree, set linkage between the newborn blocks, write them if sync is
556  * required, recheck the path, free and repeat if check fails, otherwise
557  * set the last missing link (that will protect us from any truncate-generated
558  * removals - all blocks on the path are immune now) and possibly force the
559  * write on the parent block.
560  * That has a nice additional property: no special recovery from the failed
561  * allocations is needed - we simply release blocks and do not touch anything
562  * reachable from inode.
563  *
564  * `handle' can be NULL if create == 0.
565  *
566  * return > 0, # of blocks mapped or allocated.
567  * return = 0, if plain lookup failed.
568  * return < 0, error case.
569  */
570 static int ext2_get_blocks(struct inode *inode,
571                            sector_t iblock, unsigned long maxblocks,
572                            struct buffer_head *bh_result,
573                            int create)
574 {
575         int err = -EIO;
576         int offsets[4];
577         Indirect chain[4];
578         Indirect *partial;
579         ext2_fsblk_t goal;
580         int indirect_blks;
581         int blocks_to_boundary = 0;
582         int depth;
583         struct ext2_inode_info *ei = EXT2_I(inode);
584         int count = 0;
585         ext2_fsblk_t first_block = 0;
586
587         depth = ext2_block_to_path(inode,iblock,offsets,&blocks_to_boundary);
588
589         if (depth == 0)
590                 return (err);
591
592         partial = ext2_get_branch(inode, depth, offsets, chain, &err);
593         /* Simplest case - block found, no allocation needed */
594         if (!partial) {
595                 first_block = le32_to_cpu(chain[depth - 1].key);
596                 clear_buffer_new(bh_result); /* What's this do? */
597                 count++;
598                 /*map more blocks*/
599                 while (count < maxblocks && count <= blocks_to_boundary) {
600                         ext2_fsblk_t blk;
601
602                         if (!verify_chain(chain, chain + depth - 1)) {
603                                 /*
604                                  * Indirect block might be removed by
605                                  * truncate while we were reading it.
606                                  * Handling of that case: forget what we've
607                                  * got now, go to reread.
608                                  */
609                                 err = -EAGAIN;
610                                 count = 0;
611                                 break;
612                         }
613                         blk = le32_to_cpu(*(chain[depth-1].p + count));
614                         if (blk == first_block + count)
615                                 count++;
616                         else
617                                 break;
618                 }
619                 if (err != -EAGAIN)
620                         goto got_it;
621         }
622
623         /* Next simple case - plain lookup or failed read of indirect block */
624         if (!create || err == -EIO)
625                 goto cleanup;
626
627         mutex_lock(&ei->truncate_mutex);
628         /*
629          * If the indirect block is missing while we are reading
630          * the chain(ext3_get_branch() returns -EAGAIN err), or
631          * if the chain has been changed after we grab the semaphore,
632          * (either because another process truncated this branch, or
633          * another get_block allocated this branch) re-grab the chain to see if
634          * the request block has been allocated or not.
635          *
636          * Since we already block the truncate/other get_block
637          * at this point, we will have the current copy of the chain when we
638          * splice the branch into the tree.
639          */
640         if (err == -EAGAIN || !verify_chain(chain, partial)) {
641                 while (partial > chain) {
642                         brelse(partial->bh);
643                         partial--;
644                 }
645                 partial = ext2_get_branch(inode, depth, offsets, chain, &err);
646                 if (!partial) {
647                         count++;
648                         mutex_unlock(&ei->truncate_mutex);
649                         if (err)
650                                 goto cleanup;
651                         clear_buffer_new(bh_result);
652                         goto got_it;
653                 }
654         }
655
656         /*
657          * Okay, we need to do block allocation.  Lazily initialize the block
658          * allocation info here if necessary
659         */
660         if (S_ISREG(inode->i_mode) && (!ei->i_block_alloc_info))
661                 ext2_init_block_alloc_info(inode);
662
663         goal = ext2_find_goal(inode, iblock, partial);
664
665         /* the number of blocks need to allocate for [d,t]indirect blocks */
666         indirect_blks = (chain + depth) - partial - 1;
667         /*
668          * Next look up the indirect map to count the totoal number of
669          * direct blocks to allocate for this branch.
670          */
671         count = ext2_blks_to_allocate(partial, indirect_blks,
672                                         maxblocks, blocks_to_boundary);
673         /*
674          * XXX ???? Block out ext2_truncate while we alter the tree
675          */
676         err = ext2_alloc_branch(inode, indirect_blks, &count, goal,
677                                 offsets + (partial - chain), partial);
678
679         if (err) {
680                 mutex_unlock(&ei->truncate_mutex);
681                 goto cleanup;
682         }
683
684         if (ext2_use_xip(inode->i_sb)) {
685                 /*
686                  * we need to clear the block
687                  */
688                 err = ext2_clear_xip_target (inode,
689                         le32_to_cpu(chain[depth-1].key));
690                 if (err) {
691                         mutex_unlock(&ei->truncate_mutex);
692                         goto cleanup;
693                 }
694         }
695
696         ext2_splice_branch(inode, iblock, partial, indirect_blks, count);
697         mutex_unlock(&ei->truncate_mutex);
698         set_buffer_new(bh_result);
699 got_it:
700         map_bh(bh_result, inode->i_sb, le32_to_cpu(chain[depth-1].key));
701         if (count > blocks_to_boundary)
702                 set_buffer_boundary(bh_result);
703         err = count;
704         /* Clean up and exit */
705         partial = chain + depth - 1;    /* the whole chain */
706 cleanup:
707         while (partial > chain) {
708                 brelse(partial->bh);
709                 partial--;
710         }
711         return err;
712 }
713
714 int ext2_get_block(struct inode *inode, sector_t iblock, struct buffer_head *bh_result, int create)
715 {
716         unsigned max_blocks = bh_result->b_size >> inode->i_blkbits;
717         int ret = ext2_get_blocks(inode, iblock, max_blocks,
718                               bh_result, create);
719         if (ret > 0) {
720                 bh_result->b_size = (ret << inode->i_blkbits);
721                 ret = 0;
722         }
723         return ret;
724
725 }
726
727 int ext2_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
728                 u64 start, u64 len)
729 {
730         return generic_block_fiemap(inode, fieinfo, start, len,
731                                     ext2_get_block);
732 }
733
734 static int ext2_writepage(struct page *page, struct writeback_control *wbc)
735 {
736         return block_write_full_page(page, ext2_get_block, wbc);
737 }
738
739 static int ext2_readpage(struct file *file, struct page *page)
740 {
741         return mpage_readpage(page, ext2_get_block);
742 }
743
744 static int
745 ext2_readpages(struct file *file, struct address_space *mapping,
746                 struct list_head *pages, unsigned nr_pages)
747 {
748         return mpage_readpages(mapping, pages, nr_pages, ext2_get_block);
749 }
750
751 int __ext2_write_begin(struct file *file, struct address_space *mapping,
752                 loff_t pos, unsigned len, unsigned flags,
753                 struct page **pagep, void **fsdata)
754 {
755         return block_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
756                                                         ext2_get_block);
757 }
758
759 static int
760 ext2_write_begin(struct file *file, struct address_space *mapping,
761                 loff_t pos, unsigned len, unsigned flags,
762                 struct page **pagep, void **fsdata)
763 {
764         *pagep = NULL;
765         return __ext2_write_begin(file, mapping, pos, len, flags, pagep,fsdata);
766 }
767
768 static int
769 ext2_nobh_write_begin(struct file *file, struct address_space *mapping,
770                 loff_t pos, unsigned len, unsigned flags,
771                 struct page **pagep, void **fsdata)
772 {
773         /*
774          * Dir-in-pagecache still uses ext2_write_begin. Would have to rework
775          * directory handling code to pass around offsets rather than struct
776          * pages in order to make this work easily.
777          */
778         return nobh_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
779                                                         ext2_get_block);
780 }
781
782 static int ext2_nobh_writepage(struct page *page,
783                         struct writeback_control *wbc)
784 {
785         return nobh_writepage(page, ext2_get_block, wbc);
786 }
787
788 static sector_t ext2_bmap(struct address_space *mapping, sector_t block)
789 {
790         return generic_block_bmap(mapping,block,ext2_get_block);
791 }
792
793 static ssize_t
794 ext2_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
795                         loff_t offset, unsigned long nr_segs)
796 {
797         struct file *file = iocb->ki_filp;
798         struct inode *inode = file->f_mapping->host;
799
800         return blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iov,
801                                 offset, nr_segs, ext2_get_block, NULL);
802 }
803
804 static int
805 ext2_writepages(struct address_space *mapping, struct writeback_control *wbc)
806 {
807         return mpage_writepages(mapping, wbc, ext2_get_block);
808 }
809
810 const struct address_space_operations ext2_aops = {
811         .readpage               = ext2_readpage,
812         .readpages              = ext2_readpages,
813         .writepage              = ext2_writepage,
814         .sync_page              = block_sync_page,
815         .write_begin            = ext2_write_begin,
816         .write_end              = generic_write_end,
817         .bmap                   = ext2_bmap,
818         .direct_IO              = ext2_direct_IO,
819         .writepages             = ext2_writepages,
820         .migratepage            = buffer_migrate_page,
821         .is_partially_uptodate  = block_is_partially_uptodate,
822 };
823
824 const struct address_space_operations ext2_aops_xip = {
825         .bmap                   = ext2_bmap,
826         .get_xip_mem            = ext2_get_xip_mem,
827 };
828
829 const struct address_space_operations ext2_nobh_aops = {
830         .readpage               = ext2_readpage,
831         .readpages              = ext2_readpages,
832         .writepage              = ext2_nobh_writepage,
833         .sync_page              = block_sync_page,
834         .write_begin            = ext2_nobh_write_begin,
835         .write_end              = nobh_write_end,
836         .bmap                   = ext2_bmap,
837         .direct_IO              = ext2_direct_IO,
838         .writepages             = ext2_writepages,
839         .migratepage            = buffer_migrate_page,
840 };
841
842 /*
843  * Probably it should be a library function... search for first non-zero word
844  * or memcmp with zero_page, whatever is better for particular architecture.
845  * Linus?
846  */
847 static inline int all_zeroes(__le32 *p, __le32 *q)
848 {
849         while (p < q)
850                 if (*p++)
851                         return 0;
852         return 1;
853 }
854
855 /**
856  *      ext2_find_shared - find the indirect blocks for partial truncation.
857  *      @inode:   inode in question
858  *      @depth:   depth of the affected branch
859  *      @offsets: offsets of pointers in that branch (see ext2_block_to_path)
860  *      @chain:   place to store the pointers to partial indirect blocks
861  *      @top:     place to the (detached) top of branch
862  *
863  *      This is a helper function used by ext2_truncate().
864  *
865  *      When we do truncate() we may have to clean the ends of several indirect
866  *      blocks but leave the blocks themselves alive. Block is partially
867  *      truncated if some data below the new i_size is refered from it (and
868  *      it is on the path to the first completely truncated data block, indeed).
869  *      We have to free the top of that path along with everything to the right
870  *      of the path. Since no allocation past the truncation point is possible
871  *      until ext2_truncate() finishes, we may safely do the latter, but top
872  *      of branch may require special attention - pageout below the truncation
873  *      point might try to populate it.
874  *
875  *      We atomically detach the top of branch from the tree, store the block
876  *      number of its root in *@top, pointers to buffer_heads of partially
877  *      truncated blocks - in @chain[].bh and pointers to their last elements
878  *      that should not be removed - in @chain[].p. Return value is the pointer
879  *      to last filled element of @chain.
880  *
881  *      The work left to caller to do the actual freeing of subtrees:
882  *              a) free the subtree starting from *@top
883  *              b) free the subtrees whose roots are stored in
884  *                      (@chain[i].p+1 .. end of @chain[i].bh->b_data)
885  *              c) free the subtrees growing from the inode past the @chain[0].p
886  *                      (no partially truncated stuff there).
887  */
888
889 static Indirect *ext2_find_shared(struct inode *inode,
890                                 int depth,
891                                 int offsets[4],
892                                 Indirect chain[4],
893                                 __le32 *top)
894 {
895         Indirect *partial, *p;
896         int k, err;
897
898         *top = 0;
899         for (k = depth; k > 1 && !offsets[k-1]; k--)
900                 ;
901         partial = ext2_get_branch(inode, k, offsets, chain, &err);
902         if (!partial)
903                 partial = chain + k-1;
904         /*
905          * If the branch acquired continuation since we've looked at it -
906          * fine, it should all survive and (new) top doesn't belong to us.
907          */
908         write_lock(&EXT2_I(inode)->i_meta_lock);
909         if (!partial->key && *partial->p) {
910                 write_unlock(&EXT2_I(inode)->i_meta_lock);
911                 goto no_top;
912         }
913         for (p=partial; p>chain && all_zeroes((__le32*)p->bh->b_data,p->p); p--)
914                 ;
915         /*
916          * OK, we've found the last block that must survive. The rest of our
917          * branch should be detached before unlocking. However, if that rest
918          * of branch is all ours and does not grow immediately from the inode
919          * it's easier to cheat and just decrement partial->p.
920          */
921         if (p == chain + k - 1 && p > chain) {
922                 p->p--;
923         } else {
924                 *top = *p->p;
925                 *p->p = 0;
926         }
927         write_unlock(&EXT2_I(inode)->i_meta_lock);
928
929         while(partial > p)
930         {
931                 brelse(partial->bh);
932                 partial--;
933         }
934 no_top:
935         return partial;
936 }
937
938 /**
939  *      ext2_free_data - free a list of data blocks
940  *      @inode: inode we are dealing with
941  *      @p:     array of block numbers
942  *      @q:     points immediately past the end of array
943  *
944  *      We are freeing all blocks refered from that array (numbers are
945  *      stored as little-endian 32-bit) and updating @inode->i_blocks
946  *      appropriately.
947  */
948 static inline void ext2_free_data(struct inode *inode, __le32 *p, __le32 *q)
949 {
950         unsigned long block_to_free = 0, count = 0;
951         unsigned long nr;
952
953         for ( ; p < q ; p++) {
954                 nr = le32_to_cpu(*p);
955                 if (nr) {
956                         *p = 0;
957                         /* accumulate blocks to free if they're contiguous */
958                         if (count == 0)
959                                 goto free_this;
960                         else if (block_to_free == nr - count)
961                                 count++;
962                         else {
963                                 mark_inode_dirty(inode);
964                                 ext2_free_blocks (inode, block_to_free, count);
965                         free_this:
966                                 block_to_free = nr;
967                                 count = 1;
968                         }
969                 }
970         }
971         if (count > 0) {
972                 mark_inode_dirty(inode);
973                 ext2_free_blocks (inode, block_to_free, count);
974         }
975 }
976
977 /**
978  *      ext2_free_branches - free an array of branches
979  *      @inode: inode we are dealing with
980  *      @p:     array of block numbers
981  *      @q:     pointer immediately past the end of array
982  *      @depth: depth of the branches to free
983  *
984  *      We are freeing all blocks refered from these branches (numbers are
985  *      stored as little-endian 32-bit) and updating @inode->i_blocks
986  *      appropriately.
987  */
988 static void ext2_free_branches(struct inode *inode, __le32 *p, __le32 *q, int depth)
989 {
990         struct buffer_head * bh;
991         unsigned long nr;
992
993         if (depth--) {
994                 int addr_per_block = EXT2_ADDR_PER_BLOCK(inode->i_sb);
995                 for ( ; p < q ; p++) {
996                         nr = le32_to_cpu(*p);
997                         if (!nr)
998                                 continue;
999                         *p = 0;
1000                         bh = sb_bread(inode->i_sb, nr);
1001                         /*
1002                          * A read failure? Report error and clear slot
1003                          * (should be rare).
1004                          */ 
1005                         if (!bh) {
1006                                 ext2_error(inode->i_sb, "ext2_free_branches",
1007                                         "Read failure, inode=%ld, block=%ld",
1008                                         inode->i_ino, nr);
1009                                 continue;
1010                         }
1011                         ext2_free_branches(inode,
1012                                            (__le32*)bh->b_data,
1013                                            (__le32*)bh->b_data + addr_per_block,
1014                                            depth);
1015                         bforget(bh);
1016                         ext2_free_blocks(inode, nr, 1);
1017                         mark_inode_dirty(inode);
1018                 }
1019         } else
1020                 ext2_free_data(inode, p, q);
1021 }
1022
1023 void ext2_truncate(struct inode *inode)
1024 {
1025         __le32 *i_data = EXT2_I(inode)->i_data;
1026         struct ext2_inode_info *ei = EXT2_I(inode);
1027         int addr_per_block = EXT2_ADDR_PER_BLOCK(inode->i_sb);
1028         int offsets[4];
1029         Indirect chain[4];
1030         Indirect *partial;
1031         __le32 nr = 0;
1032         int n;
1033         long iblock;
1034         unsigned blocksize;
1035
1036         if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
1037             S_ISLNK(inode->i_mode)))
1038                 return;
1039         if (ext2_inode_is_fast_symlink(inode))
1040                 return;
1041         if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
1042                 return;
1043
1044         blocksize = inode->i_sb->s_blocksize;
1045         iblock = (inode->i_size + blocksize-1)
1046                                         >> EXT2_BLOCK_SIZE_BITS(inode->i_sb);
1047
1048         if (mapping_is_xip(inode->i_mapping))
1049                 xip_truncate_page(inode->i_mapping, inode->i_size);
1050         else if (test_opt(inode->i_sb, NOBH))
1051                 nobh_truncate_page(inode->i_mapping,
1052                                 inode->i_size, ext2_get_block);
1053         else
1054                 block_truncate_page(inode->i_mapping,
1055                                 inode->i_size, ext2_get_block);
1056
1057         n = ext2_block_to_path(inode, iblock, offsets, NULL);
1058         if (n == 0)
1059                 return;
1060
1061         /*
1062          * From here we block out all ext2_get_block() callers who want to
1063          * modify the block allocation tree.
1064          */
1065         mutex_lock(&ei->truncate_mutex);
1066
1067         if (n == 1) {
1068                 ext2_free_data(inode, i_data+offsets[0],
1069                                         i_data + EXT2_NDIR_BLOCKS);
1070                 goto do_indirects;
1071         }
1072
1073         partial = ext2_find_shared(inode, n, offsets, chain, &nr);
1074         /* Kill the top of shared branch (already detached) */
1075         if (nr) {
1076                 if (partial == chain)
1077                         mark_inode_dirty(inode);
1078                 else
1079                         mark_buffer_dirty_inode(partial->bh, inode);
1080                 ext2_free_branches(inode, &nr, &nr+1, (chain+n-1) - partial);
1081         }
1082         /* Clear the ends of indirect blocks on the shared branch */
1083         while (partial > chain) {
1084                 ext2_free_branches(inode,
1085                                    partial->p + 1,
1086                                    (__le32*)partial->bh->b_data+addr_per_block,
1087                                    (chain+n-1) - partial);
1088                 mark_buffer_dirty_inode(partial->bh, inode);
1089                 brelse (partial->bh);
1090                 partial--;
1091         }
1092 do_indirects:
1093         /* Kill the remaining (whole) subtrees */
1094         switch (offsets[0]) {
1095                 default:
1096                         nr = i_data[EXT2_IND_BLOCK];
1097                         if (nr) {
1098                                 i_data[EXT2_IND_BLOCK] = 0;
1099                                 mark_inode_dirty(inode);
1100                                 ext2_free_branches(inode, &nr, &nr+1, 1);
1101                         }
1102                 case EXT2_IND_BLOCK:
1103                         nr = i_data[EXT2_DIND_BLOCK];
1104                         if (nr) {
1105                                 i_data[EXT2_DIND_BLOCK] = 0;
1106                                 mark_inode_dirty(inode);
1107                                 ext2_free_branches(inode, &nr, &nr+1, 2);
1108                         }
1109                 case EXT2_DIND_BLOCK:
1110                         nr = i_data[EXT2_TIND_BLOCK];
1111                         if (nr) {
1112                                 i_data[EXT2_TIND_BLOCK] = 0;
1113                                 mark_inode_dirty(inode);
1114                                 ext2_free_branches(inode, &nr, &nr+1, 3);
1115                         }
1116                 case EXT2_TIND_BLOCK:
1117                         ;
1118         }
1119
1120         ext2_discard_reservation(inode);
1121
1122         mutex_unlock(&ei->truncate_mutex);
1123         inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC;
1124         if (inode_needs_sync(inode)) {
1125                 sync_mapping_buffers(inode->i_mapping);
1126                 ext2_sync_inode (inode);
1127         } else {
1128                 mark_inode_dirty(inode);
1129         }
1130 }
1131
1132 static struct ext2_inode *ext2_get_inode(struct super_block *sb, ino_t ino,
1133                                         struct buffer_head **p)
1134 {
1135         struct buffer_head * bh;
1136         unsigned long block_group;
1137         unsigned long block;
1138         unsigned long offset;
1139         struct ext2_group_desc * gdp;
1140
1141         *p = NULL;
1142         if ((ino != EXT2_ROOT_INO && ino < EXT2_FIRST_INO(sb)) ||
1143             ino > le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count))
1144                 goto Einval;
1145
1146         block_group = (ino - 1) / EXT2_INODES_PER_GROUP(sb);
1147         gdp = ext2_get_group_desc(sb, block_group, NULL);
1148         if (!gdp)
1149                 goto Egdp;
1150         /*
1151          * Figure out the offset within the block group inode table
1152          */
1153         offset = ((ino - 1) % EXT2_INODES_PER_GROUP(sb)) * EXT2_INODE_SIZE(sb);
1154         block = le32_to_cpu(gdp->bg_inode_table) +
1155                 (offset >> EXT2_BLOCK_SIZE_BITS(sb));
1156         if (!(bh = sb_bread(sb, block)))
1157                 goto Eio;
1158
1159         *p = bh;
1160         offset &= (EXT2_BLOCK_SIZE(sb) - 1);
1161         return (struct ext2_inode *) (bh->b_data + offset);
1162
1163 Einval:
1164         ext2_error(sb, "ext2_get_inode", "bad inode number: %lu",
1165                    (unsigned long) ino);
1166         return ERR_PTR(-EINVAL);
1167 Eio:
1168         ext2_error(sb, "ext2_get_inode",
1169                    "unable to read inode block - inode=%lu, block=%lu",
1170                    (unsigned long) ino, block);
1171 Egdp:
1172         return ERR_PTR(-EIO);
1173 }
1174
1175 void ext2_set_inode_flags(struct inode *inode)
1176 {
1177         unsigned int flags = EXT2_I(inode)->i_flags;
1178
1179         inode->i_flags &= ~(S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC);
1180         if (flags & EXT2_SYNC_FL)
1181                 inode->i_flags |= S_SYNC;
1182         if (flags & EXT2_APPEND_FL)
1183                 inode->i_flags |= S_APPEND;
1184         if (flags & EXT2_IMMUTABLE_FL)
1185                 inode->i_flags |= S_IMMUTABLE;
1186         if (flags & EXT2_NOATIME_FL)
1187                 inode->i_flags |= S_NOATIME;
1188         if (flags & EXT2_DIRSYNC_FL)
1189                 inode->i_flags |= S_DIRSYNC;
1190 }
1191
1192 /* Propagate flags from i_flags to EXT2_I(inode)->i_flags */
1193 void ext2_get_inode_flags(struct ext2_inode_info *ei)
1194 {
1195         unsigned int flags = ei->vfs_inode.i_flags;
1196
1197         ei->i_flags &= ~(EXT2_SYNC_FL|EXT2_APPEND_FL|
1198                         EXT2_IMMUTABLE_FL|EXT2_NOATIME_FL|EXT2_DIRSYNC_FL);
1199         if (flags & S_SYNC)
1200                 ei->i_flags |= EXT2_SYNC_FL;
1201         if (flags & S_APPEND)
1202                 ei->i_flags |= EXT2_APPEND_FL;
1203         if (flags & S_IMMUTABLE)
1204                 ei->i_flags |= EXT2_IMMUTABLE_FL;
1205         if (flags & S_NOATIME)
1206                 ei->i_flags |= EXT2_NOATIME_FL;
1207         if (flags & S_DIRSYNC)
1208                 ei->i_flags |= EXT2_DIRSYNC_FL;
1209 }
1210
1211 struct inode *ext2_iget (struct super_block *sb, unsigned long ino)
1212 {
1213         struct ext2_inode_info *ei;
1214         struct buffer_head * bh;
1215         struct ext2_inode *raw_inode;
1216         struct inode *inode;
1217         long ret = -EIO;
1218         int n;
1219
1220         inode = iget_locked(sb, ino);
1221         if (!inode)
1222                 return ERR_PTR(-ENOMEM);
1223         if (!(inode->i_state & I_NEW))
1224                 return inode;
1225
1226         ei = EXT2_I(inode);
1227 #ifdef CONFIG_EXT2_FS_POSIX_ACL
1228         ei->i_acl = EXT2_ACL_NOT_CACHED;
1229         ei->i_default_acl = EXT2_ACL_NOT_CACHED;
1230 #endif
1231         ei->i_block_alloc_info = NULL;
1232
1233         raw_inode = ext2_get_inode(inode->i_sb, ino, &bh);
1234         if (IS_ERR(raw_inode)) {
1235                 ret = PTR_ERR(raw_inode);
1236                 goto bad_inode;
1237         }
1238
1239         inode->i_mode = le16_to_cpu(raw_inode->i_mode);
1240         inode->i_uid = (uid_t)le16_to_cpu(raw_inode->i_uid_low);
1241         inode->i_gid = (gid_t)le16_to_cpu(raw_inode->i_gid_low);
1242         if (!(test_opt (inode->i_sb, NO_UID32))) {
1243                 inode->i_uid |= le16_to_cpu(raw_inode->i_uid_high) << 16;
1244                 inode->i_gid |= le16_to_cpu(raw_inode->i_gid_high) << 16;
1245         }
1246         inode->i_nlink = le16_to_cpu(raw_inode->i_links_count);
1247         inode->i_size = le32_to_cpu(raw_inode->i_size);
1248         inode->i_atime.tv_sec = (signed)le32_to_cpu(raw_inode->i_atime);
1249         inode->i_ctime.tv_sec = (signed)le32_to_cpu(raw_inode->i_ctime);
1250         inode->i_mtime.tv_sec = (signed)le32_to_cpu(raw_inode->i_mtime);
1251         inode->i_atime.tv_nsec = inode->i_mtime.tv_nsec = inode->i_ctime.tv_nsec = 0;
1252         ei->i_dtime = le32_to_cpu(raw_inode->i_dtime);
1253         /* We now have enough fields to check if the inode was active or not.
1254          * This is needed because nfsd might try to access dead inodes
1255          * the test is that same one that e2fsck uses
1256          * NeilBrown 1999oct15
1257          */
1258         if (inode->i_nlink == 0 && (inode->i_mode == 0 || ei->i_dtime)) {
1259                 /* this inode is deleted */
1260                 brelse (bh);
1261                 ret = -ESTALE;
1262                 goto bad_inode;
1263         }
1264         inode->i_blocks = le32_to_cpu(raw_inode->i_blocks);
1265         ei->i_flags = le32_to_cpu(raw_inode->i_flags);
1266         ei->i_faddr = le32_to_cpu(raw_inode->i_faddr);
1267         ei->i_frag_no = raw_inode->i_frag;
1268         ei->i_frag_size = raw_inode->i_fsize;
1269         ei->i_file_acl = le32_to_cpu(raw_inode->i_file_acl);
1270         ei->i_dir_acl = 0;
1271         if (S_ISREG(inode->i_mode))
1272                 inode->i_size |= ((__u64)le32_to_cpu(raw_inode->i_size_high)) << 32;
1273         else
1274                 ei->i_dir_acl = le32_to_cpu(raw_inode->i_dir_acl);
1275         ei->i_dtime = 0;
1276         inode->i_generation = le32_to_cpu(raw_inode->i_generation);
1277         ei->i_state = 0;
1278         ei->i_block_group = (ino - 1) / EXT2_INODES_PER_GROUP(inode->i_sb);
1279         ei->i_dir_start_lookup = 0;
1280
1281         /*
1282          * NOTE! The in-memory inode i_data array is in little-endian order
1283          * even on big-endian machines: we do NOT byteswap the block numbers!
1284          */
1285         for (n = 0; n < EXT2_N_BLOCKS; n++)
1286                 ei->i_data[n] = raw_inode->i_block[n];
1287
1288         if (S_ISREG(inode->i_mode)) {
1289                 inode->i_op = &ext2_file_inode_operations;
1290                 if (ext2_use_xip(inode->i_sb)) {
1291                         inode->i_mapping->a_ops = &ext2_aops_xip;
1292                         inode->i_fop = &ext2_xip_file_operations;
1293                 } else if (test_opt(inode->i_sb, NOBH)) {
1294                         inode->i_mapping->a_ops = &ext2_nobh_aops;
1295                         inode->i_fop = &ext2_file_operations;
1296                 } else {
1297                         inode->i_mapping->a_ops = &ext2_aops;
1298                         inode->i_fop = &ext2_file_operations;
1299                 }
1300         } else if (S_ISDIR(inode->i_mode)) {
1301                 inode->i_op = &ext2_dir_inode_operations;
1302                 inode->i_fop = &ext2_dir_operations;
1303                 if (test_opt(inode->i_sb, NOBH))
1304                         inode->i_mapping->a_ops = &ext2_nobh_aops;
1305                 else
1306                         inode->i_mapping->a_ops = &ext2_aops;
1307         } else if (S_ISLNK(inode->i_mode)) {
1308                 if (ext2_inode_is_fast_symlink(inode)) {
1309                         inode->i_op = &ext2_fast_symlink_inode_operations;
1310                         nd_terminate_link(ei->i_data, inode->i_size,
1311                                 sizeof(ei->i_data) - 1);
1312                 } else {
1313                         inode->i_op = &ext2_symlink_inode_operations;
1314                         if (test_opt(inode->i_sb, NOBH))
1315                                 inode->i_mapping->a_ops = &ext2_nobh_aops;
1316                         else
1317                                 inode->i_mapping->a_ops = &ext2_aops;
1318                 }
1319         } else {
1320                 inode->i_op = &ext2_special_inode_operations;
1321                 if (raw_inode->i_block[0])
1322                         init_special_inode(inode, inode->i_mode,
1323                            old_decode_dev(le32_to_cpu(raw_inode->i_block[0])));
1324                 else 
1325                         init_special_inode(inode, inode->i_mode,
1326                            new_decode_dev(le32_to_cpu(raw_inode->i_block[1])));
1327         }
1328         brelse (bh);
1329         ext2_set_inode_flags(inode);
1330         unlock_new_inode(inode);
1331         return inode;
1332         
1333 bad_inode:
1334         iget_failed(inode);
1335         return ERR_PTR(ret);
1336 }
1337
1338 int ext2_write_inode(struct inode *inode, int do_sync)
1339 {
1340         struct ext2_inode_info *ei = EXT2_I(inode);
1341         struct super_block *sb = inode->i_sb;
1342         ino_t ino = inode->i_ino;
1343         uid_t uid = inode->i_uid;
1344         gid_t gid = inode->i_gid;
1345         struct buffer_head * bh;
1346         struct ext2_inode * raw_inode = ext2_get_inode(sb, ino, &bh);
1347         int n;
1348         int err = 0;
1349
1350         if (IS_ERR(raw_inode))
1351                 return -EIO;
1352
1353         /* For fields not not tracking in the in-memory inode,
1354          * initialise them to zero for new inodes. */
1355         if (ei->i_state & EXT2_STATE_NEW)
1356                 memset(raw_inode, 0, EXT2_SB(sb)->s_inode_size);
1357
1358         ext2_get_inode_flags(ei);
1359         raw_inode->i_mode = cpu_to_le16(inode->i_mode);
1360         if (!(test_opt(sb, NO_UID32))) {
1361                 raw_inode->i_uid_low = cpu_to_le16(low_16_bits(uid));
1362                 raw_inode->i_gid_low = cpu_to_le16(low_16_bits(gid));
1363 /*
1364  * Fix up interoperability with old kernels. Otherwise, old inodes get
1365  * re-used with the upper 16 bits of the uid/gid intact
1366  */
1367                 if (!ei->i_dtime) {
1368                         raw_inode->i_uid_high = cpu_to_le16(high_16_bits(uid));
1369                         raw_inode->i_gid_high = cpu_to_le16(high_16_bits(gid));
1370                 } else {
1371                         raw_inode->i_uid_high = 0;
1372                         raw_inode->i_gid_high = 0;
1373                 }
1374         } else {
1375                 raw_inode->i_uid_low = cpu_to_le16(fs_high2lowuid(uid));
1376                 raw_inode->i_gid_low = cpu_to_le16(fs_high2lowgid(gid));
1377                 raw_inode->i_uid_high = 0;
1378                 raw_inode->i_gid_high = 0;
1379         }
1380         raw_inode->i_links_count = cpu_to_le16(inode->i_nlink);
1381         raw_inode->i_size = cpu_to_le32(inode->i_size);
1382         raw_inode->i_atime = cpu_to_le32(inode->i_atime.tv_sec);
1383         raw_inode->i_ctime = cpu_to_le32(inode->i_ctime.tv_sec);
1384         raw_inode->i_mtime = cpu_to_le32(inode->i_mtime.tv_sec);
1385
1386         raw_inode->i_blocks = cpu_to_le32(inode->i_blocks);
1387         raw_inode->i_dtime = cpu_to_le32(ei->i_dtime);
1388         raw_inode->i_flags = cpu_to_le32(ei->i_flags);
1389         raw_inode->i_faddr = cpu_to_le32(ei->i_faddr);
1390         raw_inode->i_frag = ei->i_frag_no;
1391         raw_inode->i_fsize = ei->i_frag_size;
1392         raw_inode->i_file_acl = cpu_to_le32(ei->i_file_acl);
1393         if (!S_ISREG(inode->i_mode))
1394                 raw_inode->i_dir_acl = cpu_to_le32(ei->i_dir_acl);
1395         else {
1396                 raw_inode->i_size_high = cpu_to_le32(inode->i_size >> 32);
1397                 if (inode->i_size > 0x7fffffffULL) {
1398                         if (!EXT2_HAS_RO_COMPAT_FEATURE(sb,
1399                                         EXT2_FEATURE_RO_COMPAT_LARGE_FILE) ||
1400                             EXT2_SB(sb)->s_es->s_rev_level ==
1401                                         cpu_to_le32(EXT2_GOOD_OLD_REV)) {
1402                                /* If this is the first large file
1403                                 * created, add a flag to the superblock.
1404                                 */
1405                                 lock_kernel();
1406                                 ext2_update_dynamic_rev(sb);
1407                                 EXT2_SET_RO_COMPAT_FEATURE(sb,
1408                                         EXT2_FEATURE_RO_COMPAT_LARGE_FILE);
1409                                 unlock_kernel();
1410                                 ext2_write_super(sb);
1411                         }
1412                 }
1413         }
1414         
1415         raw_inode->i_generation = cpu_to_le32(inode->i_generation);
1416         if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) {
1417                 if (old_valid_dev(inode->i_rdev)) {
1418                         raw_inode->i_block[0] =
1419                                 cpu_to_le32(old_encode_dev(inode->i_rdev));
1420                         raw_inode->i_block[1] = 0;
1421                 } else {
1422                         raw_inode->i_block[0] = 0;
1423                         raw_inode->i_block[1] =
1424                                 cpu_to_le32(new_encode_dev(inode->i_rdev));
1425                         raw_inode->i_block[2] = 0;
1426                 }
1427         } else for (n = 0; n < EXT2_N_BLOCKS; n++)
1428                 raw_inode->i_block[n] = ei->i_data[n];
1429         mark_buffer_dirty(bh);
1430         if (do_sync) {
1431                 sync_dirty_buffer(bh);
1432                 if (buffer_req(bh) && !buffer_uptodate(bh)) {
1433                         printk ("IO error syncing ext2 inode [%s:%08lx]\n",
1434                                 sb->s_id, (unsigned long) ino);
1435                         err = -EIO;
1436                 }
1437         }
1438         ei->i_state &= ~EXT2_STATE_NEW;
1439         brelse (bh);
1440         return err;
1441 }
1442
1443 int ext2_sync_inode(struct inode *inode)
1444 {
1445         struct writeback_control wbc = {
1446                 .sync_mode = WB_SYNC_ALL,
1447                 .nr_to_write = 0,       /* sys_fsync did this */
1448         };
1449         return sync_inode(inode, &wbc);
1450 }
1451
1452 int ext2_setattr(struct dentry *dentry, struct iattr *iattr)
1453 {
1454         struct inode *inode = dentry->d_inode;
1455         int error;
1456
1457         error = inode_change_ok(inode, iattr);
1458         if (error)
1459                 return error;
1460         if ((iattr->ia_valid & ATTR_UID && iattr->ia_uid != inode->i_uid) ||
1461             (iattr->ia_valid & ATTR_GID && iattr->ia_gid != inode->i_gid)) {
1462                 error = vfs_dq_transfer(inode, iattr) ? -EDQUOT : 0;
1463                 if (error)
1464                         return error;
1465         }
1466         error = inode_setattr(inode, iattr);
1467         if (!error && (iattr->ia_valid & ATTR_MODE))
1468                 error = ext2_acl_chmod(inode);
1469         return error;
1470 }