ext4: calculate and verify block bitmap checksum
[pandora-kernel.git] / fs / ext4 / resize.c
1 /*
2  *  linux/fs/ext4/resize.c
3  *
4  * Support for resizing an ext4 filesystem while it is mounted.
5  *
6  * Copyright (C) 2001, 2002 Andreas Dilger <adilger@clusterfs.com>
7  *
8  * This could probably be made into a module, because it is not often in use.
9  */
10
11
12 #define EXT4FS_DEBUG
13
14 #include <linux/errno.h>
15 #include <linux/slab.h>
16
17 #include "ext4_jbd2.h"
18
19 int ext4_resize_begin(struct super_block *sb)
20 {
21         int ret = 0;
22
23         if (!capable(CAP_SYS_RESOURCE))
24                 return -EPERM;
25
26         /*
27          * We are not allowed to do online-resizing on a filesystem mounted
28          * with error, because it can destroy the filesystem easily.
29          */
30         if (EXT4_SB(sb)->s_mount_state & EXT4_ERROR_FS) {
31                 ext4_warning(sb, "There are errors in the filesystem, "
32                              "so online resizing is not allowed\n");
33                 return -EPERM;
34         }
35
36         if (test_and_set_bit_lock(EXT4_RESIZING, &EXT4_SB(sb)->s_resize_flags))
37                 ret = -EBUSY;
38
39         return ret;
40 }
41
42 void ext4_resize_end(struct super_block *sb)
43 {
44         clear_bit_unlock(EXT4_RESIZING, &EXT4_SB(sb)->s_resize_flags);
45         smp_mb__after_clear_bit();
46 }
47
48 #define outside(b, first, last) ((b) < (first) || (b) >= (last))
49 #define inside(b, first, last)  ((b) >= (first) && (b) < (last))
50
51 static int verify_group_input(struct super_block *sb,
52                               struct ext4_new_group_data *input)
53 {
54         struct ext4_sb_info *sbi = EXT4_SB(sb);
55         struct ext4_super_block *es = sbi->s_es;
56         ext4_fsblk_t start = ext4_blocks_count(es);
57         ext4_fsblk_t end = start + input->blocks_count;
58         ext4_group_t group = input->group;
59         ext4_fsblk_t itend = input->inode_table + sbi->s_itb_per_group;
60         unsigned overhead = ext4_bg_has_super(sb, group) ?
61                 (1 + ext4_bg_num_gdb(sb, group) +
62                  le16_to_cpu(es->s_reserved_gdt_blocks)) : 0;
63         ext4_fsblk_t metaend = start + overhead;
64         struct buffer_head *bh = NULL;
65         ext4_grpblk_t free_blocks_count, offset;
66         int err = -EINVAL;
67
68         input->free_blocks_count = free_blocks_count =
69                 input->blocks_count - 2 - overhead - sbi->s_itb_per_group;
70
71         if (test_opt(sb, DEBUG))
72                 printk(KERN_DEBUG "EXT4-fs: adding %s group %u: %u blocks "
73                        "(%d free, %u reserved)\n",
74                        ext4_bg_has_super(sb, input->group) ? "normal" :
75                        "no-super", input->group, input->blocks_count,
76                        free_blocks_count, input->reserved_blocks);
77
78         ext4_get_group_no_and_offset(sb, start, NULL, &offset);
79         if (group != sbi->s_groups_count)
80                 ext4_warning(sb, "Cannot add at group %u (only %u groups)",
81                              input->group, sbi->s_groups_count);
82         else if (offset != 0)
83                         ext4_warning(sb, "Last group not full");
84         else if (input->reserved_blocks > input->blocks_count / 5)
85                 ext4_warning(sb, "Reserved blocks too high (%u)",
86                              input->reserved_blocks);
87         else if (free_blocks_count < 0)
88                 ext4_warning(sb, "Bad blocks count %u",
89                              input->blocks_count);
90         else if (!(bh = sb_bread(sb, end - 1)))
91                 ext4_warning(sb, "Cannot read last block (%llu)",
92                              end - 1);
93         else if (outside(input->block_bitmap, start, end))
94                 ext4_warning(sb, "Block bitmap not in group (block %llu)",
95                              (unsigned long long)input->block_bitmap);
96         else if (outside(input->inode_bitmap, start, end))
97                 ext4_warning(sb, "Inode bitmap not in group (block %llu)",
98                              (unsigned long long)input->inode_bitmap);
99         else if (outside(input->inode_table, start, end) ||
100                  outside(itend - 1, start, end))
101                 ext4_warning(sb, "Inode table not in group (blocks %llu-%llu)",
102                              (unsigned long long)input->inode_table, itend - 1);
103         else if (input->inode_bitmap == input->block_bitmap)
104                 ext4_warning(sb, "Block bitmap same as inode bitmap (%llu)",
105                              (unsigned long long)input->block_bitmap);
106         else if (inside(input->block_bitmap, input->inode_table, itend))
107                 ext4_warning(sb, "Block bitmap (%llu) in inode table "
108                              "(%llu-%llu)",
109                              (unsigned long long)input->block_bitmap,
110                              (unsigned long long)input->inode_table, itend - 1);
111         else if (inside(input->inode_bitmap, input->inode_table, itend))
112                 ext4_warning(sb, "Inode bitmap (%llu) in inode table "
113                              "(%llu-%llu)",
114                              (unsigned long long)input->inode_bitmap,
115                              (unsigned long long)input->inode_table, itend - 1);
116         else if (inside(input->block_bitmap, start, metaend))
117                 ext4_warning(sb, "Block bitmap (%llu) in GDT table (%llu-%llu)",
118                              (unsigned long long)input->block_bitmap,
119                              start, metaend - 1);
120         else if (inside(input->inode_bitmap, start, metaend))
121                 ext4_warning(sb, "Inode bitmap (%llu) in GDT table (%llu-%llu)",
122                              (unsigned long long)input->inode_bitmap,
123                              start, metaend - 1);
124         else if (inside(input->inode_table, start, metaend) ||
125                  inside(itend - 1, start, metaend))
126                 ext4_warning(sb, "Inode table (%llu-%llu) overlaps GDT table "
127                              "(%llu-%llu)",
128                              (unsigned long long)input->inode_table,
129                              itend - 1, start, metaend - 1);
130         else
131                 err = 0;
132         brelse(bh);
133
134         return err;
135 }
136
137 /*
138  * ext4_new_flex_group_data is used by 64bit-resize interface to add a flex
139  * group each time.
140  */
141 struct ext4_new_flex_group_data {
142         struct ext4_new_group_data *groups;     /* new_group_data for groups
143                                                    in the flex group */
144         __u16 *bg_flags;                        /* block group flags of groups
145                                                    in @groups */
146         ext4_group_t count;                     /* number of groups in @groups
147                                                  */
148 };
149
150 /*
151  * alloc_flex_gd() allocates a ext4_new_flex_group_data with size of
152  * @flexbg_size.
153  *
154  * Returns NULL on failure otherwise address of the allocated structure.
155  */
156 static struct ext4_new_flex_group_data *alloc_flex_gd(unsigned long flexbg_size)
157 {
158         struct ext4_new_flex_group_data *flex_gd;
159
160         flex_gd = kmalloc(sizeof(*flex_gd), GFP_NOFS);
161         if (flex_gd == NULL)
162                 goto out3;
163
164         flex_gd->count = flexbg_size;
165
166         flex_gd->groups = kmalloc(sizeof(struct ext4_new_group_data) *
167                                   flexbg_size, GFP_NOFS);
168         if (flex_gd->groups == NULL)
169                 goto out2;
170
171         flex_gd->bg_flags = kmalloc(flexbg_size * sizeof(__u16), GFP_NOFS);
172         if (flex_gd->bg_flags == NULL)
173                 goto out1;
174
175         return flex_gd;
176
177 out1:
178         kfree(flex_gd->groups);
179 out2:
180         kfree(flex_gd);
181 out3:
182         return NULL;
183 }
184
185 static void free_flex_gd(struct ext4_new_flex_group_data *flex_gd)
186 {
187         kfree(flex_gd->bg_flags);
188         kfree(flex_gd->groups);
189         kfree(flex_gd);
190 }
191
192 /*
193  * ext4_alloc_group_tables() allocates block bitmaps, inode bitmaps
194  * and inode tables for a flex group.
195  *
196  * This function is used by 64bit-resize.  Note that this function allocates
197  * group tables from the 1st group of groups contained by @flexgd, which may
198  * be a partial of a flex group.
199  *
200  * @sb: super block of fs to which the groups belongs
201  */
202 static void ext4_alloc_group_tables(struct super_block *sb,
203                                 struct ext4_new_flex_group_data *flex_gd,
204                                 int flexbg_size)
205 {
206         struct ext4_new_group_data *group_data = flex_gd->groups;
207         struct ext4_super_block *es = EXT4_SB(sb)->s_es;
208         ext4_fsblk_t start_blk;
209         ext4_fsblk_t last_blk;
210         ext4_group_t src_group;
211         ext4_group_t bb_index = 0;
212         ext4_group_t ib_index = 0;
213         ext4_group_t it_index = 0;
214         ext4_group_t group;
215         ext4_group_t last_group;
216         unsigned overhead;
217
218         BUG_ON(flex_gd->count == 0 || group_data == NULL);
219
220         src_group = group_data[0].group;
221         last_group  = src_group + flex_gd->count - 1;
222
223         BUG_ON((flexbg_size > 1) && ((src_group & ~(flexbg_size - 1)) !=
224                (last_group & ~(flexbg_size - 1))));
225 next_group:
226         group = group_data[0].group;
227         start_blk = ext4_group_first_block_no(sb, src_group);
228         last_blk = start_blk + group_data[src_group - group].blocks_count;
229
230         overhead = ext4_bg_has_super(sb, src_group) ?
231                    (1 + ext4_bg_num_gdb(sb, src_group) +
232                     le16_to_cpu(es->s_reserved_gdt_blocks)) : 0;
233
234         start_blk += overhead;
235
236         BUG_ON(src_group >= group_data[0].group + flex_gd->count);
237         /* We collect contiguous blocks as much as possible. */
238         src_group++;
239         for (; src_group <= last_group; src_group++)
240                 if (!ext4_bg_has_super(sb, src_group))
241                         last_blk += group_data[src_group - group].blocks_count;
242                 else
243                         break;
244
245         /* Allocate block bitmaps */
246         for (; bb_index < flex_gd->count; bb_index++) {
247                 if (start_blk >= last_blk)
248                         goto next_group;
249                 group_data[bb_index].block_bitmap = start_blk++;
250                 ext4_get_group_no_and_offset(sb, start_blk - 1, &group, NULL);
251                 group -= group_data[0].group;
252                 group_data[group].free_blocks_count--;
253                 if (flexbg_size > 1)
254                         flex_gd->bg_flags[group] &= ~EXT4_BG_BLOCK_UNINIT;
255         }
256
257         /* Allocate inode bitmaps */
258         for (; ib_index < flex_gd->count; ib_index++) {
259                 if (start_blk >= last_blk)
260                         goto next_group;
261                 group_data[ib_index].inode_bitmap = start_blk++;
262                 ext4_get_group_no_and_offset(sb, start_blk - 1, &group, NULL);
263                 group -= group_data[0].group;
264                 group_data[group].free_blocks_count--;
265                 if (flexbg_size > 1)
266                         flex_gd->bg_flags[group] &= ~EXT4_BG_BLOCK_UNINIT;
267         }
268
269         /* Allocate inode tables */
270         for (; it_index < flex_gd->count; it_index++) {
271                 if (start_blk + EXT4_SB(sb)->s_itb_per_group > last_blk)
272                         goto next_group;
273                 group_data[it_index].inode_table = start_blk;
274                 ext4_get_group_no_and_offset(sb, start_blk, &group, NULL);
275                 group -= group_data[0].group;
276                 group_data[group].free_blocks_count -=
277                                         EXT4_SB(sb)->s_itb_per_group;
278                 if (flexbg_size > 1)
279                         flex_gd->bg_flags[group] &= ~EXT4_BG_BLOCK_UNINIT;
280
281                 start_blk += EXT4_SB(sb)->s_itb_per_group;
282         }
283
284         if (test_opt(sb, DEBUG)) {
285                 int i;
286                 group = group_data[0].group;
287
288                 printk(KERN_DEBUG "EXT4-fs: adding a flex group with "
289                        "%d groups, flexbg size is %d:\n", flex_gd->count,
290                        flexbg_size);
291
292                 for (i = 0; i < flex_gd->count; i++) {
293                         printk(KERN_DEBUG "adding %s group %u: %u "
294                                "blocks (%d free)\n",
295                                ext4_bg_has_super(sb, group + i) ? "normal" :
296                                "no-super", group + i,
297                                group_data[i].blocks_count,
298                                group_data[i].free_blocks_count);
299                 }
300         }
301 }
302
303 static struct buffer_head *bclean(handle_t *handle, struct super_block *sb,
304                                   ext4_fsblk_t blk)
305 {
306         struct buffer_head *bh;
307         int err;
308
309         bh = sb_getblk(sb, blk);
310         if (!bh)
311                 return ERR_PTR(-EIO);
312         if ((err = ext4_journal_get_write_access(handle, bh))) {
313                 brelse(bh);
314                 bh = ERR_PTR(err);
315         } else {
316                 memset(bh->b_data, 0, sb->s_blocksize);
317                 set_buffer_uptodate(bh);
318         }
319
320         return bh;
321 }
322
323 /*
324  * If we have fewer than thresh credits, extend by EXT4_MAX_TRANS_DATA.
325  * If that fails, restart the transaction & regain write access for the
326  * buffer head which is used for block_bitmap modifications.
327  */
328 static int extend_or_restart_transaction(handle_t *handle, int thresh)
329 {
330         int err;
331
332         if (ext4_handle_has_enough_credits(handle, thresh))
333                 return 0;
334
335         err = ext4_journal_extend(handle, EXT4_MAX_TRANS_DATA);
336         if (err < 0)
337                 return err;
338         if (err) {
339                 err = ext4_journal_restart(handle, EXT4_MAX_TRANS_DATA);
340                 if (err)
341                         return err;
342         }
343
344         return 0;
345 }
346
347 /*
348  * set_flexbg_block_bitmap() mark @count blocks starting from @block used.
349  *
350  * Helper function for ext4_setup_new_group_blocks() which set .
351  *
352  * @sb: super block
353  * @handle: journal handle
354  * @flex_gd: flex group data
355  */
356 static int set_flexbg_block_bitmap(struct super_block *sb, handle_t *handle,
357                         struct ext4_new_flex_group_data *flex_gd,
358                         ext4_fsblk_t block, ext4_group_t count)
359 {
360         ext4_group_t count2;
361
362         ext4_debug("mark blocks [%llu/%u] used\n", block, count);
363         for (count2 = count; count > 0; count -= count2, block += count2) {
364                 ext4_fsblk_t start;
365                 struct buffer_head *bh;
366                 ext4_group_t group;
367                 int err;
368
369                 ext4_get_group_no_and_offset(sb, block, &group, NULL);
370                 start = ext4_group_first_block_no(sb, group);
371                 group -= flex_gd->groups[0].group;
372
373                 count2 = sb->s_blocksize * 8 - (block - start);
374                 if (count2 > count)
375                         count2 = count;
376
377                 if (flex_gd->bg_flags[group] & EXT4_BG_BLOCK_UNINIT) {
378                         BUG_ON(flex_gd->count > 1);
379                         continue;
380                 }
381
382                 err = extend_or_restart_transaction(handle, 1);
383                 if (err)
384                         return err;
385
386                 bh = sb_getblk(sb, flex_gd->groups[group].block_bitmap);
387                 if (!bh)
388                         return -EIO;
389
390                 err = ext4_journal_get_write_access(handle, bh);
391                 if (err)
392                         return err;
393                 ext4_debug("mark block bitmap %#04llx (+%llu/%u)\n", block,
394                            block - start, count2);
395                 ext4_set_bits(bh->b_data, block - start, count2);
396
397                 err = ext4_handle_dirty_metadata(handle, NULL, bh);
398                 if (unlikely(err))
399                         return err;
400                 brelse(bh);
401         }
402
403         return 0;
404 }
405
406 /*
407  * Set up the block and inode bitmaps, and the inode table for the new groups.
408  * This doesn't need to be part of the main transaction, since we are only
409  * changing blocks outside the actual filesystem.  We still do journaling to
410  * ensure the recovery is correct in case of a failure just after resize.
411  * If any part of this fails, we simply abort the resize.
412  *
413  * setup_new_flex_group_blocks handles a flex group as follow:
414  *  1. copy super block and GDT, and initialize group tables if necessary.
415  *     In this step, we only set bits in blocks bitmaps for blocks taken by
416  *     super block and GDT.
417  *  2. allocate group tables in block bitmaps, that is, set bits in block
418  *     bitmap for blocks taken by group tables.
419  */
420 static int setup_new_flex_group_blocks(struct super_block *sb,
421                                 struct ext4_new_flex_group_data *flex_gd)
422 {
423         int group_table_count[] = {1, 1, EXT4_SB(sb)->s_itb_per_group};
424         ext4_fsblk_t start;
425         ext4_fsblk_t block;
426         struct ext4_sb_info *sbi = EXT4_SB(sb);
427         struct ext4_super_block *es = sbi->s_es;
428         struct ext4_new_group_data *group_data = flex_gd->groups;
429         __u16 *bg_flags = flex_gd->bg_flags;
430         handle_t *handle;
431         ext4_group_t group, count;
432         struct buffer_head *bh = NULL;
433         int reserved_gdb, i, j, err = 0, err2;
434
435         BUG_ON(!flex_gd->count || !group_data ||
436                group_data[0].group != sbi->s_groups_count);
437
438         reserved_gdb = le16_to_cpu(es->s_reserved_gdt_blocks);
439
440         /* This transaction may be extended/restarted along the way */
441         handle = ext4_journal_start_sb(sb, EXT4_MAX_TRANS_DATA);
442         if (IS_ERR(handle))
443                 return PTR_ERR(handle);
444
445         group = group_data[0].group;
446         for (i = 0; i < flex_gd->count; i++, group++) {
447                 unsigned long gdblocks;
448
449                 gdblocks = ext4_bg_num_gdb(sb, group);
450                 start = ext4_group_first_block_no(sb, group);
451
452                 /* Copy all of the GDT blocks into the backup in this group */
453                 for (j = 0, block = start + 1; j < gdblocks; j++, block++) {
454                         struct buffer_head *gdb;
455
456                         ext4_debug("update backup group %#04llx\n", block);
457                         err = extend_or_restart_transaction(handle, 1);
458                         if (err)
459                                 goto out;
460
461                         gdb = sb_getblk(sb, block);
462                         if (!gdb) {
463                                 err = -EIO;
464                                 goto out;
465                         }
466
467                         err = ext4_journal_get_write_access(handle, gdb);
468                         if (err) {
469                                 brelse(gdb);
470                                 goto out;
471                         }
472                         memcpy(gdb->b_data, sbi->s_group_desc[j]->b_data,
473                                gdb->b_size);
474                         set_buffer_uptodate(gdb);
475
476                         err = ext4_handle_dirty_metadata(handle, NULL, gdb);
477                         if (unlikely(err)) {
478                                 brelse(gdb);
479                                 goto out;
480                         }
481                         brelse(gdb);
482                 }
483
484                 /* Zero out all of the reserved backup group descriptor
485                  * table blocks
486                  */
487                 if (ext4_bg_has_super(sb, group)) {
488                         err = sb_issue_zeroout(sb, gdblocks + start + 1,
489                                         reserved_gdb, GFP_NOFS);
490                         if (err)
491                                 goto out;
492                 }
493
494                 /* Initialize group tables of the grop @group */
495                 if (!(bg_flags[i] & EXT4_BG_INODE_ZEROED))
496                         goto handle_bb;
497
498                 /* Zero out all of the inode table blocks */
499                 block = group_data[i].inode_table;
500                 ext4_debug("clear inode table blocks %#04llx -> %#04lx\n",
501                            block, sbi->s_itb_per_group);
502                 err = sb_issue_zeroout(sb, block, sbi->s_itb_per_group,
503                                        GFP_NOFS);
504                 if (err)
505                         goto out;
506
507 handle_bb:
508                 if (bg_flags[i] & EXT4_BG_BLOCK_UNINIT)
509                         goto handle_ib;
510
511                 /* Initialize block bitmap of the @group */
512                 block = group_data[i].block_bitmap;
513                 err = extend_or_restart_transaction(handle, 1);
514                 if (err)
515                         goto out;
516
517                 bh = bclean(handle, sb, block);
518                 if (IS_ERR(bh)) {
519                         err = PTR_ERR(bh);
520                         goto out;
521                 }
522                 if (ext4_bg_has_super(sb, group)) {
523                         ext4_debug("mark backup superblock %#04llx (+0)\n",
524                                    start);
525                         ext4_set_bits(bh->b_data, 0, gdblocks + reserved_gdb +
526                                                      1);
527                 }
528                 ext4_mark_bitmap_end(group_data[i].blocks_count,
529                                      sb->s_blocksize * 8, bh->b_data);
530                 err = ext4_handle_dirty_metadata(handle, NULL, bh);
531                 if (err)
532                         goto out;
533                 brelse(bh);
534
535 handle_ib:
536                 if (bg_flags[i] & EXT4_BG_INODE_UNINIT)
537                         continue;
538
539                 /* Initialize inode bitmap of the @group */
540                 block = group_data[i].inode_bitmap;
541                 err = extend_or_restart_transaction(handle, 1);
542                 if (err)
543                         goto out;
544                 /* Mark unused entries in inode bitmap used */
545                 bh = bclean(handle, sb, block);
546                 if (IS_ERR(bh)) {
547                         err = PTR_ERR(bh);
548                         goto out;
549                 }
550
551                 ext4_mark_bitmap_end(EXT4_INODES_PER_GROUP(sb),
552                                      sb->s_blocksize * 8, bh->b_data);
553                 err = ext4_handle_dirty_metadata(handle, NULL, bh);
554                 if (err)
555                         goto out;
556                 brelse(bh);
557         }
558         bh = NULL;
559
560         /* Mark group tables in block bitmap */
561         for (j = 0; j < GROUP_TABLE_COUNT; j++) {
562                 count = group_table_count[j];
563                 start = (&group_data[0].block_bitmap)[j];
564                 block = start;
565                 for (i = 1; i < flex_gd->count; i++) {
566                         block += group_table_count[j];
567                         if (block == (&group_data[i].block_bitmap)[j]) {
568                                 count += group_table_count[j];
569                                 continue;
570                         }
571                         err = set_flexbg_block_bitmap(sb, handle,
572                                                 flex_gd, start, count);
573                         if (err)
574                                 goto out;
575                         count = group_table_count[j];
576                         start = group_data[i].block_bitmap;
577                         block = start;
578                 }
579
580                 if (count) {
581                         err = set_flexbg_block_bitmap(sb, handle,
582                                                 flex_gd, start, count);
583                         if (err)
584                                 goto out;
585                 }
586         }
587
588 out:
589         brelse(bh);
590         err2 = ext4_journal_stop(handle);
591         if (err2 && !err)
592                 err = err2;
593
594         return err;
595 }
596
597 /*
598  * Iterate through the groups which hold BACKUP superblock/GDT copies in an
599  * ext4 filesystem.  The counters should be initialized to 1, 5, and 7 before
600  * calling this for the first time.  In a sparse filesystem it will be the
601  * sequence of powers of 3, 5, and 7: 1, 3, 5, 7, 9, 25, 27, 49, 81, ...
602  * For a non-sparse filesystem it will be every group: 1, 2, 3, 4, ...
603  */
604 static unsigned ext4_list_backups(struct super_block *sb, unsigned *three,
605                                   unsigned *five, unsigned *seven)
606 {
607         unsigned *min = three;
608         int mult = 3;
609         unsigned ret;
610
611         if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
612                                         EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER)) {
613                 ret = *min;
614                 *min += 1;
615                 return ret;
616         }
617
618         if (*five < *min) {
619                 min = five;
620                 mult = 5;
621         }
622         if (*seven < *min) {
623                 min = seven;
624                 mult = 7;
625         }
626
627         ret = *min;
628         *min *= mult;
629
630         return ret;
631 }
632
633 /*
634  * Check that all of the backup GDT blocks are held in the primary GDT block.
635  * It is assumed that they are stored in group order.  Returns the number of
636  * groups in current filesystem that have BACKUPS, or -ve error code.
637  */
638 static int verify_reserved_gdb(struct super_block *sb,
639                                ext4_group_t end,
640                                struct buffer_head *primary)
641 {
642         const ext4_fsblk_t blk = primary->b_blocknr;
643         unsigned three = 1;
644         unsigned five = 5;
645         unsigned seven = 7;
646         unsigned grp;
647         __le32 *p = (__le32 *)primary->b_data;
648         int gdbackups = 0;
649
650         while ((grp = ext4_list_backups(sb, &three, &five, &seven)) < end) {
651                 if (le32_to_cpu(*p++) !=
652                     grp * EXT4_BLOCKS_PER_GROUP(sb) + blk){
653                         ext4_warning(sb, "reserved GDT %llu"
654                                      " missing grp %d (%llu)",
655                                      blk, grp,
656                                      grp *
657                                      (ext4_fsblk_t)EXT4_BLOCKS_PER_GROUP(sb) +
658                                      blk);
659                         return -EINVAL;
660                 }
661                 if (++gdbackups > EXT4_ADDR_PER_BLOCK(sb))
662                         return -EFBIG;
663         }
664
665         return gdbackups;
666 }
667
668 /*
669  * Called when we need to bring a reserved group descriptor table block into
670  * use from the resize inode.  The primary copy of the new GDT block currently
671  * is an indirect block (under the double indirect block in the resize inode).
672  * The new backup GDT blocks will be stored as leaf blocks in this indirect
673  * block, in group order.  Even though we know all the block numbers we need,
674  * we check to ensure that the resize inode has actually reserved these blocks.
675  *
676  * Don't need to update the block bitmaps because the blocks are still in use.
677  *
678  * We get all of the error cases out of the way, so that we are sure to not
679  * fail once we start modifying the data on disk, because JBD has no rollback.
680  */
681 static int add_new_gdb(handle_t *handle, struct inode *inode,
682                        ext4_group_t group)
683 {
684         struct super_block *sb = inode->i_sb;
685         struct ext4_super_block *es = EXT4_SB(sb)->s_es;
686         unsigned long gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
687         ext4_fsblk_t gdblock = EXT4_SB(sb)->s_sbh->b_blocknr + 1 + gdb_num;
688         struct buffer_head **o_group_desc, **n_group_desc;
689         struct buffer_head *dind;
690         struct buffer_head *gdb_bh;
691         int gdbackups;
692         struct ext4_iloc iloc;
693         __le32 *data;
694         int err;
695
696         if (test_opt(sb, DEBUG))
697                 printk(KERN_DEBUG
698                        "EXT4-fs: ext4_add_new_gdb: adding group block %lu\n",
699                        gdb_num);
700
701         /*
702          * If we are not using the primary superblock/GDT copy don't resize,
703          * because the user tools have no way of handling this.  Probably a
704          * bad time to do it anyways.
705          */
706         if (EXT4_SB(sb)->s_sbh->b_blocknr !=
707             le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block)) {
708                 ext4_warning(sb, "won't resize using backup superblock at %llu",
709                         (unsigned long long)EXT4_SB(sb)->s_sbh->b_blocknr);
710                 return -EPERM;
711         }
712
713         gdb_bh = sb_bread(sb, gdblock);
714         if (!gdb_bh)
715                 return -EIO;
716
717         gdbackups = verify_reserved_gdb(sb, group, gdb_bh);
718         if (gdbackups < 0) {
719                 err = gdbackups;
720                 goto exit_bh;
721         }
722
723         data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK;
724         dind = sb_bread(sb, le32_to_cpu(*data));
725         if (!dind) {
726                 err = -EIO;
727                 goto exit_bh;
728         }
729
730         data = (__le32 *)dind->b_data;
731         if (le32_to_cpu(data[gdb_num % EXT4_ADDR_PER_BLOCK(sb)]) != gdblock) {
732                 ext4_warning(sb, "new group %u GDT block %llu not reserved",
733                              group, gdblock);
734                 err = -EINVAL;
735                 goto exit_dind;
736         }
737
738         err = ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh);
739         if (unlikely(err))
740                 goto exit_dind;
741
742         err = ext4_journal_get_write_access(handle, gdb_bh);
743         if (unlikely(err))
744                 goto exit_sbh;
745
746         err = ext4_journal_get_write_access(handle, dind);
747         if (unlikely(err))
748                 ext4_std_error(sb, err);
749
750         /* ext4_reserve_inode_write() gets a reference on the iloc */
751         err = ext4_reserve_inode_write(handle, inode, &iloc);
752         if (unlikely(err))
753                 goto exit_dindj;
754
755         n_group_desc = ext4_kvmalloc((gdb_num + 1) *
756                                      sizeof(struct buffer_head *),
757                                      GFP_NOFS);
758         if (!n_group_desc) {
759                 err = -ENOMEM;
760                 ext4_warning(sb, "not enough memory for %lu groups",
761                              gdb_num + 1);
762                 goto exit_inode;
763         }
764
765         /*
766          * Finally, we have all of the possible failures behind us...
767          *
768          * Remove new GDT block from inode double-indirect block and clear out
769          * the new GDT block for use (which also "frees" the backup GDT blocks
770          * from the reserved inode).  We don't need to change the bitmaps for
771          * these blocks, because they are marked as in-use from being in the
772          * reserved inode, and will become GDT blocks (primary and backup).
773          */
774         data[gdb_num % EXT4_ADDR_PER_BLOCK(sb)] = 0;
775         err = ext4_handle_dirty_metadata(handle, NULL, dind);
776         if (unlikely(err)) {
777                 ext4_std_error(sb, err);
778                 goto exit_inode;
779         }
780         inode->i_blocks -= (gdbackups + 1) * sb->s_blocksize >> 9;
781         ext4_mark_iloc_dirty(handle, inode, &iloc);
782         memset(gdb_bh->b_data, 0, sb->s_blocksize);
783         err = ext4_handle_dirty_metadata(handle, NULL, gdb_bh);
784         if (unlikely(err)) {
785                 ext4_std_error(sb, err);
786                 goto exit_inode;
787         }
788         brelse(dind);
789
790         o_group_desc = EXT4_SB(sb)->s_group_desc;
791         memcpy(n_group_desc, o_group_desc,
792                EXT4_SB(sb)->s_gdb_count * sizeof(struct buffer_head *));
793         n_group_desc[gdb_num] = gdb_bh;
794         EXT4_SB(sb)->s_group_desc = n_group_desc;
795         EXT4_SB(sb)->s_gdb_count++;
796         ext4_kvfree(o_group_desc);
797
798         le16_add_cpu(&es->s_reserved_gdt_blocks, -1);
799         err = ext4_handle_dirty_super_now(handle, sb);
800         if (err)
801                 ext4_std_error(sb, err);
802
803         return err;
804
805 exit_inode:
806         ext4_kvfree(n_group_desc);
807         /* ext4_handle_release_buffer(handle, iloc.bh); */
808         brelse(iloc.bh);
809 exit_dindj:
810         /* ext4_handle_release_buffer(handle, dind); */
811 exit_sbh:
812         /* ext4_handle_release_buffer(handle, EXT4_SB(sb)->s_sbh); */
813 exit_dind:
814         brelse(dind);
815 exit_bh:
816         brelse(gdb_bh);
817
818         ext4_debug("leaving with error %d\n", err);
819         return err;
820 }
821
822 /*
823  * Called when we are adding a new group which has a backup copy of each of
824  * the GDT blocks (i.e. sparse group) and there are reserved GDT blocks.
825  * We need to add these reserved backup GDT blocks to the resize inode, so
826  * that they are kept for future resizing and not allocated to files.
827  *
828  * Each reserved backup GDT block will go into a different indirect block.
829  * The indirect blocks are actually the primary reserved GDT blocks,
830  * so we know in advance what their block numbers are.  We only get the
831  * double-indirect block to verify it is pointing to the primary reserved
832  * GDT blocks so we don't overwrite a data block by accident.  The reserved
833  * backup GDT blocks are stored in their reserved primary GDT block.
834  */
835 static int reserve_backup_gdb(handle_t *handle, struct inode *inode,
836                               ext4_group_t group)
837 {
838         struct super_block *sb = inode->i_sb;
839         int reserved_gdb =le16_to_cpu(EXT4_SB(sb)->s_es->s_reserved_gdt_blocks);
840         struct buffer_head **primary;
841         struct buffer_head *dind;
842         struct ext4_iloc iloc;
843         ext4_fsblk_t blk;
844         __le32 *data, *end;
845         int gdbackups = 0;
846         int res, i;
847         int err;
848
849         primary = kmalloc(reserved_gdb * sizeof(*primary), GFP_NOFS);
850         if (!primary)
851                 return -ENOMEM;
852
853         data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK;
854         dind = sb_bread(sb, le32_to_cpu(*data));
855         if (!dind) {
856                 err = -EIO;
857                 goto exit_free;
858         }
859
860         blk = EXT4_SB(sb)->s_sbh->b_blocknr + 1 + EXT4_SB(sb)->s_gdb_count;
861         data = (__le32 *)dind->b_data + (EXT4_SB(sb)->s_gdb_count %
862                                          EXT4_ADDR_PER_BLOCK(sb));
863         end = (__le32 *)dind->b_data + EXT4_ADDR_PER_BLOCK(sb);
864
865         /* Get each reserved primary GDT block and verify it holds backups */
866         for (res = 0; res < reserved_gdb; res++, blk++) {
867                 if (le32_to_cpu(*data) != blk) {
868                         ext4_warning(sb, "reserved block %llu"
869                                      " not at offset %ld",
870                                      blk,
871                                      (long)(data - (__le32 *)dind->b_data));
872                         err = -EINVAL;
873                         goto exit_bh;
874                 }
875                 primary[res] = sb_bread(sb, blk);
876                 if (!primary[res]) {
877                         err = -EIO;
878                         goto exit_bh;
879                 }
880                 gdbackups = verify_reserved_gdb(sb, group, primary[res]);
881                 if (gdbackups < 0) {
882                         brelse(primary[res]);
883                         err = gdbackups;
884                         goto exit_bh;
885                 }
886                 if (++data >= end)
887                         data = (__le32 *)dind->b_data;
888         }
889
890         for (i = 0; i < reserved_gdb; i++) {
891                 if ((err = ext4_journal_get_write_access(handle, primary[i]))) {
892                         /*
893                         int j;
894                         for (j = 0; j < i; j++)
895                                 ext4_handle_release_buffer(handle, primary[j]);
896                          */
897                         goto exit_bh;
898                 }
899         }
900
901         if ((err = ext4_reserve_inode_write(handle, inode, &iloc)))
902                 goto exit_bh;
903
904         /*
905          * Finally we can add each of the reserved backup GDT blocks from
906          * the new group to its reserved primary GDT block.
907          */
908         blk = group * EXT4_BLOCKS_PER_GROUP(sb);
909         for (i = 0; i < reserved_gdb; i++) {
910                 int err2;
911                 data = (__le32 *)primary[i]->b_data;
912                 /* printk("reserving backup %lu[%u] = %lu\n",
913                        primary[i]->b_blocknr, gdbackups,
914                        blk + primary[i]->b_blocknr); */
915                 data[gdbackups] = cpu_to_le32(blk + primary[i]->b_blocknr);
916                 err2 = ext4_handle_dirty_metadata(handle, NULL, primary[i]);
917                 if (!err)
918                         err = err2;
919         }
920         inode->i_blocks += reserved_gdb * sb->s_blocksize >> 9;
921         ext4_mark_iloc_dirty(handle, inode, &iloc);
922
923 exit_bh:
924         while (--res >= 0)
925                 brelse(primary[res]);
926         brelse(dind);
927
928 exit_free:
929         kfree(primary);
930
931         return err;
932 }
933
934 /*
935  * Update the backup copies of the ext4 metadata.  These don't need to be part
936  * of the main resize transaction, because e2fsck will re-write them if there
937  * is a problem (basically only OOM will cause a problem).  However, we
938  * _should_ update the backups if possible, in case the primary gets trashed
939  * for some reason and we need to run e2fsck from a backup superblock.  The
940  * important part is that the new block and inode counts are in the backup
941  * superblocks, and the location of the new group metadata in the GDT backups.
942  *
943  * We do not need take the s_resize_lock for this, because these
944  * blocks are not otherwise touched by the filesystem code when it is
945  * mounted.  We don't need to worry about last changing from
946  * sbi->s_groups_count, because the worst that can happen is that we
947  * do not copy the full number of backups at this time.  The resize
948  * which changed s_groups_count will backup again.
949  */
950 static void update_backups(struct super_block *sb,
951                            int blk_off, char *data, int size)
952 {
953         struct ext4_sb_info *sbi = EXT4_SB(sb);
954         const ext4_group_t last = sbi->s_groups_count;
955         const int bpg = EXT4_BLOCKS_PER_GROUP(sb);
956         unsigned three = 1;
957         unsigned five = 5;
958         unsigned seven = 7;
959         ext4_group_t group;
960         int rest = sb->s_blocksize - size;
961         handle_t *handle;
962         int err = 0, err2;
963
964         handle = ext4_journal_start_sb(sb, EXT4_MAX_TRANS_DATA);
965         if (IS_ERR(handle)) {
966                 group = 1;
967                 err = PTR_ERR(handle);
968                 goto exit_err;
969         }
970
971         ext4_superblock_csum_set(sb, (struct ext4_super_block *)data);
972
973         while ((group = ext4_list_backups(sb, &three, &five, &seven)) < last) {
974                 struct buffer_head *bh;
975
976                 /* Out of journal space, and can't get more - abort - so sad */
977                 if (ext4_handle_valid(handle) &&
978                     handle->h_buffer_credits == 0 &&
979                     ext4_journal_extend(handle, EXT4_MAX_TRANS_DATA) &&
980                     (err = ext4_journal_restart(handle, EXT4_MAX_TRANS_DATA)))
981                         break;
982
983                 bh = sb_getblk(sb, group * bpg + blk_off);
984                 if (!bh) {
985                         err = -EIO;
986                         break;
987                 }
988                 ext4_debug("update metadata backup %#04lx\n",
989                           (unsigned long)bh->b_blocknr);
990                 if ((err = ext4_journal_get_write_access(handle, bh)))
991                         break;
992                 lock_buffer(bh);
993                 memcpy(bh->b_data, data, size);
994                 if (rest)
995                         memset(bh->b_data + size, 0, rest);
996                 set_buffer_uptodate(bh);
997                 unlock_buffer(bh);
998                 err = ext4_handle_dirty_metadata(handle, NULL, bh);
999                 if (unlikely(err))
1000                         ext4_std_error(sb, err);
1001                 brelse(bh);
1002         }
1003         if ((err2 = ext4_journal_stop(handle)) && !err)
1004                 err = err2;
1005
1006         /*
1007          * Ugh! Need to have e2fsck write the backup copies.  It is too
1008          * late to revert the resize, we shouldn't fail just because of
1009          * the backup copies (they are only needed in case of corruption).
1010          *
1011          * However, if we got here we have a journal problem too, so we
1012          * can't really start a transaction to mark the superblock.
1013          * Chicken out and just set the flag on the hope it will be written
1014          * to disk, and if not - we will simply wait until next fsck.
1015          */
1016 exit_err:
1017         if (err) {
1018                 ext4_warning(sb, "can't update backup for group %u (err %d), "
1019                              "forcing fsck on next reboot", group, err);
1020                 sbi->s_mount_state &= ~EXT4_VALID_FS;
1021                 sbi->s_es->s_state &= cpu_to_le16(~EXT4_VALID_FS);
1022                 mark_buffer_dirty(sbi->s_sbh);
1023         }
1024 }
1025
1026 /*
1027  * ext4_add_new_descs() adds @count group descriptor of groups
1028  * starting at @group
1029  *
1030  * @handle: journal handle
1031  * @sb: super block
1032  * @group: the group no. of the first group desc to be added
1033  * @resize_inode: the resize inode
1034  * @count: number of group descriptors to be added
1035  */
1036 static int ext4_add_new_descs(handle_t *handle, struct super_block *sb,
1037                               ext4_group_t group, struct inode *resize_inode,
1038                               ext4_group_t count)
1039 {
1040         struct ext4_sb_info *sbi = EXT4_SB(sb);
1041         struct ext4_super_block *es = sbi->s_es;
1042         struct buffer_head *gdb_bh;
1043         int i, gdb_off, gdb_num, err = 0;
1044
1045         for (i = 0; i < count; i++, group++) {
1046                 int reserved_gdb = ext4_bg_has_super(sb, group) ?
1047                         le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
1048
1049                 gdb_off = group % EXT4_DESC_PER_BLOCK(sb);
1050                 gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
1051
1052                 /*
1053                  * We will only either add reserved group blocks to a backup group
1054                  * or remove reserved blocks for the first group in a new group block.
1055                  * Doing both would be mean more complex code, and sane people don't
1056                  * use non-sparse filesystems anymore.  This is already checked above.
1057                  */
1058                 if (gdb_off) {
1059                         gdb_bh = sbi->s_group_desc[gdb_num];
1060                         err = ext4_journal_get_write_access(handle, gdb_bh);
1061
1062                         if (!err && reserved_gdb && ext4_bg_num_gdb(sb, group))
1063                                 err = reserve_backup_gdb(handle, resize_inode, group);
1064                 } else
1065                         err = add_new_gdb(handle, resize_inode, group);
1066                 if (err)
1067                         break;
1068         }
1069         return err;
1070 }
1071
1072 static struct buffer_head *ext4_get_bitmap(struct super_block *sb, __u64 block)
1073 {
1074         struct buffer_head *bh = sb_getblk(sb, block);
1075         if (!bh)
1076                 return NULL;
1077
1078         if (bitmap_uptodate(bh))
1079                 return bh;
1080
1081         lock_buffer(bh);
1082         if (bh_submit_read(bh) < 0) {
1083                 unlock_buffer(bh);
1084                 brelse(bh);
1085                 return NULL;
1086         }
1087         unlock_buffer(bh);
1088
1089         return bh;
1090 }
1091
1092 static int ext4_set_bitmap_checksums(struct super_block *sb,
1093                                      ext4_group_t group,
1094                                      struct ext4_group_desc *gdp,
1095                                      struct ext4_new_group_data *group_data)
1096 {
1097         struct buffer_head *bh;
1098
1099         if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
1100                                         EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
1101                 return 0;
1102
1103         bh = ext4_get_bitmap(sb, group_data->inode_bitmap);
1104         if (!bh)
1105                 return -EIO;
1106         ext4_inode_bitmap_csum_set(sb, group, gdp, bh,
1107                                    EXT4_INODES_PER_GROUP(sb) / 8);
1108         brelse(bh);
1109
1110         bh = ext4_get_bitmap(sb, group_data->block_bitmap);
1111         if (!bh)
1112                 return -EIO;
1113         ext4_block_bitmap_csum_set(sb, group, gdp, bh,
1114                                    EXT4_BLOCKS_PER_GROUP(sb) / 8);
1115         brelse(bh);
1116
1117         return 0;
1118 }
1119
1120 /*
1121  * ext4_setup_new_descs() will set up the group descriptor descriptors of a flex bg
1122  */
1123 static int ext4_setup_new_descs(handle_t *handle, struct super_block *sb,
1124                                 struct ext4_new_flex_group_data *flex_gd)
1125 {
1126         struct ext4_new_group_data      *group_data = flex_gd->groups;
1127         struct ext4_group_desc          *gdp;
1128         struct ext4_sb_info             *sbi = EXT4_SB(sb);
1129         struct buffer_head              *gdb_bh;
1130         ext4_group_t                    group;
1131         __u16                           *bg_flags = flex_gd->bg_flags;
1132         int                             i, gdb_off, gdb_num, err = 0;
1133         
1134
1135         for (i = 0; i < flex_gd->count; i++, group_data++, bg_flags++) {
1136                 group = group_data->group;
1137
1138                 gdb_off = group % EXT4_DESC_PER_BLOCK(sb);
1139                 gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
1140
1141                 /*
1142                  * get_write_access() has been called on gdb_bh by ext4_add_new_desc().
1143                  */
1144                 gdb_bh = sbi->s_group_desc[gdb_num];
1145                 /* Update group descriptor block for new group */
1146                 gdp = (struct ext4_group_desc *)((char *)gdb_bh->b_data +
1147                                                  gdb_off * EXT4_DESC_SIZE(sb));
1148
1149                 memset(gdp, 0, EXT4_DESC_SIZE(sb));
1150                 ext4_block_bitmap_set(sb, gdp, group_data->block_bitmap);
1151                 ext4_inode_bitmap_set(sb, gdp, group_data->inode_bitmap);
1152                 err = ext4_set_bitmap_checksums(sb, group, gdp, group_data);
1153                 if (err) {
1154                         ext4_std_error(sb, err);
1155                         break;
1156                 }
1157
1158                 ext4_inode_table_set(sb, gdp, group_data->inode_table);
1159                 ext4_free_group_clusters_set(sb, gdp,
1160                                              EXT4_B2C(sbi, group_data->free_blocks_count));
1161                 ext4_free_inodes_set(sb, gdp, EXT4_INODES_PER_GROUP(sb));
1162                 gdp->bg_flags = cpu_to_le16(*bg_flags);
1163                 gdp->bg_checksum = ext4_group_desc_csum(sbi, group, gdp);
1164
1165                 err = ext4_handle_dirty_metadata(handle, NULL, gdb_bh);
1166                 if (unlikely(err)) {
1167                         ext4_std_error(sb, err);
1168                         break;
1169                 }
1170
1171                 /*
1172                  * We can allocate memory for mb_alloc based on the new group
1173                  * descriptor
1174                  */
1175                 err = ext4_mb_add_groupinfo(sb, group, gdp);
1176                 if (err)
1177                         break;
1178         }
1179         return err;
1180 }
1181
1182 /*
1183  * ext4_update_super() updates the super block so that the newly added
1184  * groups can be seen by the filesystem.
1185  *
1186  * @sb: super block
1187  * @flex_gd: new added groups
1188  */
1189 static void ext4_update_super(struct super_block *sb,
1190                              struct ext4_new_flex_group_data *flex_gd)
1191 {
1192         ext4_fsblk_t blocks_count = 0;
1193         ext4_fsblk_t free_blocks = 0;
1194         ext4_fsblk_t reserved_blocks = 0;
1195         struct ext4_new_group_data *group_data = flex_gd->groups;
1196         struct ext4_sb_info *sbi = EXT4_SB(sb);
1197         struct ext4_super_block *es = sbi->s_es;
1198         int i;
1199
1200         BUG_ON(flex_gd->count == 0 || group_data == NULL);
1201         /*
1202          * Make the new blocks and inodes valid next.  We do this before
1203          * increasing the group count so that once the group is enabled,
1204          * all of its blocks and inodes are already valid.
1205          *
1206          * We always allocate group-by-group, then block-by-block or
1207          * inode-by-inode within a group, so enabling these
1208          * blocks/inodes before the group is live won't actually let us
1209          * allocate the new space yet.
1210          */
1211         for (i = 0; i < flex_gd->count; i++) {
1212                 blocks_count += group_data[i].blocks_count;
1213                 free_blocks += group_data[i].free_blocks_count;
1214         }
1215
1216         reserved_blocks = ext4_r_blocks_count(es) * 100;
1217         do_div(reserved_blocks, ext4_blocks_count(es));
1218         reserved_blocks *= blocks_count;
1219         do_div(reserved_blocks, 100);
1220
1221         ext4_blocks_count_set(es, ext4_blocks_count(es) + blocks_count);
1222         ext4_free_blocks_count_set(es, ext4_free_blocks_count(es) + free_blocks);
1223         le32_add_cpu(&es->s_inodes_count, EXT4_INODES_PER_GROUP(sb) *
1224                      flex_gd->count);
1225         le32_add_cpu(&es->s_free_inodes_count, EXT4_INODES_PER_GROUP(sb) *
1226                      flex_gd->count);
1227
1228         /*
1229          * We need to protect s_groups_count against other CPUs seeing
1230          * inconsistent state in the superblock.
1231          *
1232          * The precise rules we use are:
1233          *
1234          * * Writers must perform a smp_wmb() after updating all
1235          *   dependent data and before modifying the groups count
1236          *
1237          * * Readers must perform an smp_rmb() after reading the groups
1238          *   count and before reading any dependent data.
1239          *
1240          * NB. These rules can be relaxed when checking the group count
1241          * while freeing data, as we can only allocate from a block
1242          * group after serialising against the group count, and we can
1243          * only then free after serialising in turn against that
1244          * allocation.
1245          */
1246         smp_wmb();
1247
1248         /* Update the global fs size fields */
1249         sbi->s_groups_count += flex_gd->count;
1250
1251         /* Update the reserved block counts only once the new group is
1252          * active. */
1253         ext4_r_blocks_count_set(es, ext4_r_blocks_count(es) +
1254                                 reserved_blocks);
1255
1256         /* Update the free space counts */
1257         percpu_counter_add(&sbi->s_freeclusters_counter,
1258                            EXT4_B2C(sbi, free_blocks));
1259         percpu_counter_add(&sbi->s_freeinodes_counter,
1260                            EXT4_INODES_PER_GROUP(sb) * flex_gd->count);
1261
1262         if (EXT4_HAS_INCOMPAT_FEATURE(sb,
1263                                       EXT4_FEATURE_INCOMPAT_FLEX_BG) &&
1264             sbi->s_log_groups_per_flex) {
1265                 ext4_group_t flex_group;
1266                 flex_group = ext4_flex_group(sbi, group_data[0].group);
1267                 atomic_add(EXT4_B2C(sbi, free_blocks),
1268                            &sbi->s_flex_groups[flex_group].free_clusters);
1269                 atomic_add(EXT4_INODES_PER_GROUP(sb) * flex_gd->count,
1270                            &sbi->s_flex_groups[flex_group].free_inodes);
1271         }
1272
1273         if (test_opt(sb, DEBUG))
1274                 printk(KERN_DEBUG "EXT4-fs: added group %u:"
1275                        "%llu blocks(%llu free %llu reserved)\n", flex_gd->count,
1276                        blocks_count, free_blocks, reserved_blocks);
1277 }
1278
1279 /* Add a flex group to an fs. Ensure we handle all possible error conditions
1280  * _before_ we start modifying the filesystem, because we cannot abort the
1281  * transaction and not have it write the data to disk.
1282  */
1283 static int ext4_flex_group_add(struct super_block *sb,
1284                                struct inode *resize_inode,
1285                                struct ext4_new_flex_group_data *flex_gd)
1286 {
1287         struct ext4_sb_info *sbi = EXT4_SB(sb);
1288         struct ext4_super_block *es = sbi->s_es;
1289         ext4_fsblk_t o_blocks_count;
1290         ext4_grpblk_t last;
1291         ext4_group_t group;
1292         handle_t *handle;
1293         unsigned reserved_gdb;
1294         int err = 0, err2 = 0, credit;
1295
1296         BUG_ON(!flex_gd->count || !flex_gd->groups || !flex_gd->bg_flags);
1297
1298         reserved_gdb = le16_to_cpu(es->s_reserved_gdt_blocks);
1299         o_blocks_count = ext4_blocks_count(es);
1300         ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
1301         BUG_ON(last);
1302
1303         err = setup_new_flex_group_blocks(sb, flex_gd);
1304         if (err)
1305                 goto exit;
1306         /*
1307          * We will always be modifying at least the superblock and  GDT
1308          * block.  If we are adding a group past the last current GDT block,
1309          * we will also modify the inode and the dindirect block.  If we
1310          * are adding a group with superblock/GDT backups  we will also
1311          * modify each of the reserved GDT dindirect blocks.
1312          */
1313         credit = flex_gd->count * 4 + reserved_gdb;
1314         handle = ext4_journal_start_sb(sb, credit);
1315         if (IS_ERR(handle)) {
1316                 err = PTR_ERR(handle);
1317                 goto exit;
1318         }
1319
1320         err = ext4_journal_get_write_access(handle, sbi->s_sbh);
1321         if (err)
1322                 goto exit_journal;
1323
1324         group = flex_gd->groups[0].group;
1325         BUG_ON(group != EXT4_SB(sb)->s_groups_count);
1326         err = ext4_add_new_descs(handle, sb, group,
1327                                 resize_inode, flex_gd->count);
1328         if (err)
1329                 goto exit_journal;
1330
1331         err = ext4_setup_new_descs(handle, sb, flex_gd);
1332         if (err)
1333                 goto exit_journal;
1334
1335         ext4_update_super(sb, flex_gd);
1336
1337         err = ext4_handle_dirty_super(handle, sb);
1338
1339 exit_journal:
1340         err2 = ext4_journal_stop(handle);
1341         if (!err)
1342                 err = err2;
1343
1344         if (!err) {
1345                 int i;
1346                 update_backups(sb, sbi->s_sbh->b_blocknr, (char *)es,
1347                                sizeof(struct ext4_super_block));
1348                 for (i = 0; i < flex_gd->count; i++, group++) {
1349                         struct buffer_head *gdb_bh;
1350                         int gdb_num;
1351                         gdb_num = group / EXT4_BLOCKS_PER_GROUP(sb);
1352                         gdb_bh = sbi->s_group_desc[gdb_num];
1353                         update_backups(sb, gdb_bh->b_blocknr, gdb_bh->b_data,
1354                                        gdb_bh->b_size);
1355                 }
1356         }
1357 exit:
1358         return err;
1359 }
1360
1361 static int ext4_setup_next_flex_gd(struct super_block *sb,
1362                                     struct ext4_new_flex_group_data *flex_gd,
1363                                     ext4_fsblk_t n_blocks_count,
1364                                     unsigned long flexbg_size)
1365 {
1366         struct ext4_super_block *es = EXT4_SB(sb)->s_es;
1367         struct ext4_new_group_data *group_data = flex_gd->groups;
1368         ext4_fsblk_t o_blocks_count;
1369         ext4_group_t n_group;
1370         ext4_group_t group;
1371         ext4_group_t last_group;
1372         ext4_grpblk_t last;
1373         ext4_grpblk_t blocks_per_group;
1374         unsigned long i;
1375
1376         blocks_per_group = EXT4_BLOCKS_PER_GROUP(sb);
1377
1378         o_blocks_count = ext4_blocks_count(es);
1379
1380         if (o_blocks_count == n_blocks_count)
1381                 return 0;
1382
1383         ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
1384         BUG_ON(last);
1385         ext4_get_group_no_and_offset(sb, n_blocks_count - 1, &n_group, &last);
1386
1387         last_group = group | (flexbg_size - 1);
1388         if (last_group > n_group)
1389                 last_group = n_group;
1390
1391         flex_gd->count = last_group - group + 1;
1392
1393         for (i = 0; i < flex_gd->count; i++) {
1394                 int overhead;
1395
1396                 group_data[i].group = group + i;
1397                 group_data[i].blocks_count = blocks_per_group;
1398                 overhead = ext4_bg_has_super(sb, group + i) ?
1399                            (1 + ext4_bg_num_gdb(sb, group + i) +
1400                             le16_to_cpu(es->s_reserved_gdt_blocks)) : 0;
1401                 group_data[i].free_blocks_count = blocks_per_group - overhead;
1402                 if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
1403                                                EXT4_FEATURE_RO_COMPAT_GDT_CSUM))
1404                         flex_gd->bg_flags[i] = EXT4_BG_BLOCK_UNINIT |
1405                                                EXT4_BG_INODE_UNINIT;
1406                 else
1407                         flex_gd->bg_flags[i] = EXT4_BG_INODE_ZEROED;
1408         }
1409
1410         if (last_group == n_group &&
1411             EXT4_HAS_RO_COMPAT_FEATURE(sb,
1412                                        EXT4_FEATURE_RO_COMPAT_GDT_CSUM))
1413                 /* We need to initialize block bitmap of last group. */
1414                 flex_gd->bg_flags[i - 1] &= ~EXT4_BG_BLOCK_UNINIT;
1415
1416         if ((last_group == n_group) && (last != blocks_per_group - 1)) {
1417                 group_data[i - 1].blocks_count = last + 1;
1418                 group_data[i - 1].free_blocks_count -= blocks_per_group-
1419                                         last - 1;
1420         }
1421
1422         return 1;
1423 }
1424
1425 /* Add group descriptor data to an existing or new group descriptor block.
1426  * Ensure we handle all possible error conditions _before_ we start modifying
1427  * the filesystem, because we cannot abort the transaction and not have it
1428  * write the data to disk.
1429  *
1430  * If we are on a GDT block boundary, we need to get the reserved GDT block.
1431  * Otherwise, we may need to add backup GDT blocks for a sparse group.
1432  *
1433  * We only need to hold the superblock lock while we are actually adding
1434  * in the new group's counts to the superblock.  Prior to that we have
1435  * not really "added" the group at all.  We re-check that we are still
1436  * adding in the last group in case things have changed since verifying.
1437  */
1438 int ext4_group_add(struct super_block *sb, struct ext4_new_group_data *input)
1439 {
1440         struct ext4_new_flex_group_data flex_gd;
1441         struct ext4_sb_info *sbi = EXT4_SB(sb);
1442         struct ext4_super_block *es = sbi->s_es;
1443         int reserved_gdb = ext4_bg_has_super(sb, input->group) ?
1444                 le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
1445         struct inode *inode = NULL;
1446         int gdb_off, gdb_num;
1447         int err;
1448         __u16 bg_flags = 0;
1449
1450         gdb_num = input->group / EXT4_DESC_PER_BLOCK(sb);
1451         gdb_off = input->group % EXT4_DESC_PER_BLOCK(sb);
1452
1453         if (gdb_off == 0 && !EXT4_HAS_RO_COMPAT_FEATURE(sb,
1454                                         EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER)) {
1455                 ext4_warning(sb, "Can't resize non-sparse filesystem further");
1456                 return -EPERM;
1457         }
1458
1459         if (ext4_blocks_count(es) + input->blocks_count <
1460             ext4_blocks_count(es)) {
1461                 ext4_warning(sb, "blocks_count overflow");
1462                 return -EINVAL;
1463         }
1464
1465         if (le32_to_cpu(es->s_inodes_count) + EXT4_INODES_PER_GROUP(sb) <
1466             le32_to_cpu(es->s_inodes_count)) {
1467                 ext4_warning(sb, "inodes_count overflow");
1468                 return -EINVAL;
1469         }
1470
1471         if (reserved_gdb || gdb_off == 0) {
1472                 if (!EXT4_HAS_COMPAT_FEATURE(sb,
1473                                              EXT4_FEATURE_COMPAT_RESIZE_INODE)
1474                     || !le16_to_cpu(es->s_reserved_gdt_blocks)) {
1475                         ext4_warning(sb,
1476                                      "No reserved GDT blocks, can't resize");
1477                         return -EPERM;
1478                 }
1479                 inode = ext4_iget(sb, EXT4_RESIZE_INO);
1480                 if (IS_ERR(inode)) {
1481                         ext4_warning(sb, "Error opening resize inode");
1482                         return PTR_ERR(inode);
1483                 }
1484         }
1485
1486
1487         err = verify_group_input(sb, input);
1488         if (err)
1489                 goto out;
1490
1491         flex_gd.count = 1;
1492         flex_gd.groups = input;
1493         flex_gd.bg_flags = &bg_flags;
1494         err = ext4_flex_group_add(sb, inode, &flex_gd);
1495 out:
1496         iput(inode);
1497         return err;
1498 } /* ext4_group_add */
1499
1500 /*
1501  * extend a group without checking assuming that checking has been done.
1502  */
1503 static int ext4_group_extend_no_check(struct super_block *sb,
1504                                       ext4_fsblk_t o_blocks_count, ext4_grpblk_t add)
1505 {
1506         struct ext4_super_block *es = EXT4_SB(sb)->s_es;
1507         handle_t *handle;
1508         int err = 0, err2;
1509
1510         /* We will update the superblock, one block bitmap, and
1511          * one group descriptor via ext4_group_add_blocks().
1512          */
1513         handle = ext4_journal_start_sb(sb, 3);
1514         if (IS_ERR(handle)) {
1515                 err = PTR_ERR(handle);
1516                 ext4_warning(sb, "error %d on journal start", err);
1517                 return err;
1518         }
1519
1520         err = ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh);
1521         if (err) {
1522                 ext4_warning(sb, "error %d on journal write access", err);
1523                 goto errout;
1524         }
1525
1526         ext4_blocks_count_set(es, o_blocks_count + add);
1527         ext4_free_blocks_count_set(es, ext4_free_blocks_count(es) + add);
1528         ext4_debug("freeing blocks %llu through %llu\n", o_blocks_count,
1529                    o_blocks_count + add);
1530         /* We add the blocks to the bitmap and set the group need init bit */
1531         err = ext4_group_add_blocks(handle, sb, o_blocks_count, add);
1532         if (err)
1533                 goto errout;
1534         ext4_handle_dirty_super(handle, sb);
1535         ext4_debug("freed blocks %llu through %llu\n", o_blocks_count,
1536                    o_blocks_count + add);
1537 errout:
1538         err2 = ext4_journal_stop(handle);
1539         if (err2 && !err)
1540                 err = err2;
1541
1542         if (!err) {
1543                 if (test_opt(sb, DEBUG))
1544                         printk(KERN_DEBUG "EXT4-fs: extended group to %llu "
1545                                "blocks\n", ext4_blocks_count(es));
1546                 update_backups(sb, EXT4_SB(sb)->s_sbh->b_blocknr, (char *)es,
1547                                sizeof(struct ext4_super_block));
1548         }
1549         return err;
1550 }
1551
1552 /*
1553  * Extend the filesystem to the new number of blocks specified.  This entry
1554  * point is only used to extend the current filesystem to the end of the last
1555  * existing group.  It can be accessed via ioctl, or by "remount,resize=<size>"
1556  * for emergencies (because it has no dependencies on reserved blocks).
1557  *
1558  * If we _really_ wanted, we could use default values to call ext4_group_add()
1559  * allow the "remount" trick to work for arbitrary resizing, assuming enough
1560  * GDT blocks are reserved to grow to the desired size.
1561  */
1562 int ext4_group_extend(struct super_block *sb, struct ext4_super_block *es,
1563                       ext4_fsblk_t n_blocks_count)
1564 {
1565         ext4_fsblk_t o_blocks_count;
1566         ext4_grpblk_t last;
1567         ext4_grpblk_t add;
1568         struct buffer_head *bh;
1569         int err;
1570         ext4_group_t group;
1571
1572         o_blocks_count = ext4_blocks_count(es);
1573
1574         if (test_opt(sb, DEBUG))
1575                 ext4_msg(sb, KERN_DEBUG,
1576                          "extending last group from %llu to %llu blocks",
1577                          o_blocks_count, n_blocks_count);
1578
1579         if (n_blocks_count == 0 || n_blocks_count == o_blocks_count)
1580                 return 0;
1581
1582         if (n_blocks_count > (sector_t)(~0ULL) >> (sb->s_blocksize_bits - 9)) {
1583                 ext4_msg(sb, KERN_ERR,
1584                          "filesystem too large to resize to %llu blocks safely",
1585                          n_blocks_count);
1586                 if (sizeof(sector_t) < 8)
1587                         ext4_warning(sb, "CONFIG_LBDAF not enabled");
1588                 return -EINVAL;
1589         }
1590
1591         if (n_blocks_count < o_blocks_count) {
1592                 ext4_warning(sb, "can't shrink FS - resize aborted");
1593                 return -EINVAL;
1594         }
1595
1596         /* Handle the remaining blocks in the last group only. */
1597         ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
1598
1599         if (last == 0) {
1600                 ext4_warning(sb, "need to use ext2online to resize further");
1601                 return -EPERM;
1602         }
1603
1604         add = EXT4_BLOCKS_PER_GROUP(sb) - last;
1605
1606         if (o_blocks_count + add < o_blocks_count) {
1607                 ext4_warning(sb, "blocks_count overflow");
1608                 return -EINVAL;
1609         }
1610
1611         if (o_blocks_count + add > n_blocks_count)
1612                 add = n_blocks_count - o_blocks_count;
1613
1614         if (o_blocks_count + add < n_blocks_count)
1615                 ext4_warning(sb, "will only finish group (%llu blocks, %u new)",
1616                              o_blocks_count + add, add);
1617
1618         /* See if the device is actually as big as what was requested */
1619         bh = sb_bread(sb, o_blocks_count + add - 1);
1620         if (!bh) {
1621                 ext4_warning(sb, "can't read last block, resize aborted");
1622                 return -ENOSPC;
1623         }
1624         brelse(bh);
1625
1626         err = ext4_group_extend_no_check(sb, o_blocks_count, add);
1627         return err;
1628 } /* ext4_group_extend */
1629
1630 /*
1631  * ext4_resize_fs() resizes a fs to new size specified by @n_blocks_count
1632  *
1633  * @sb: super block of the fs to be resized
1634  * @n_blocks_count: the number of blocks resides in the resized fs
1635  */
1636 int ext4_resize_fs(struct super_block *sb, ext4_fsblk_t n_blocks_count)
1637 {
1638         struct ext4_new_flex_group_data *flex_gd = NULL;
1639         struct ext4_sb_info *sbi = EXT4_SB(sb);
1640         struct ext4_super_block *es = sbi->s_es;
1641         struct buffer_head *bh;
1642         struct inode *resize_inode;
1643         ext4_fsblk_t o_blocks_count;
1644         ext4_group_t o_group;
1645         ext4_group_t n_group;
1646         ext4_grpblk_t offset, add;
1647         unsigned long n_desc_blocks;
1648         unsigned long o_desc_blocks;
1649         unsigned long desc_blocks;
1650         int err = 0, flexbg_size = 1;
1651
1652         o_blocks_count = ext4_blocks_count(es);
1653
1654         if (test_opt(sb, DEBUG))
1655                 ext4_msg(sb, KERN_DEBUG, "resizing filesystem from %llu "
1656                        "to %llu blocks", o_blocks_count, n_blocks_count);
1657
1658         if (n_blocks_count < o_blocks_count) {
1659                 /* On-line shrinking not supported */
1660                 ext4_warning(sb, "can't shrink FS - resize aborted");
1661                 return -EINVAL;
1662         }
1663
1664         if (n_blocks_count == o_blocks_count)
1665                 /* Nothing need to do */
1666                 return 0;
1667
1668         ext4_get_group_no_and_offset(sb, n_blocks_count - 1, &n_group, &offset);
1669         ext4_get_group_no_and_offset(sb, o_blocks_count - 1, &o_group, &offset);
1670
1671         n_desc_blocks = (n_group + EXT4_DESC_PER_BLOCK(sb)) /
1672                         EXT4_DESC_PER_BLOCK(sb);
1673         o_desc_blocks = (sbi->s_groups_count + EXT4_DESC_PER_BLOCK(sb) - 1) /
1674                         EXT4_DESC_PER_BLOCK(sb);
1675         desc_blocks = n_desc_blocks - o_desc_blocks;
1676
1677         if (desc_blocks &&
1678             (!EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_RESIZE_INODE) ||
1679              le16_to_cpu(es->s_reserved_gdt_blocks) < desc_blocks)) {
1680                 ext4_warning(sb, "No reserved GDT blocks, can't resize");
1681                 return -EPERM;
1682         }
1683
1684         resize_inode = ext4_iget(sb, EXT4_RESIZE_INO);
1685         if (IS_ERR(resize_inode)) {
1686                 ext4_warning(sb, "Error opening resize inode");
1687                 return PTR_ERR(resize_inode);
1688         }
1689
1690         /* See if the device is actually as big as what was requested */
1691         bh = sb_bread(sb, n_blocks_count - 1);
1692         if (!bh) {
1693                 ext4_warning(sb, "can't read last block, resize aborted");
1694                 return -ENOSPC;
1695         }
1696         brelse(bh);
1697
1698         /* extend the last group */
1699         if (n_group == o_group)
1700                 add = n_blocks_count - o_blocks_count;
1701         else
1702                 add = EXT4_BLOCKS_PER_GROUP(sb) - (offset + 1);
1703         if (add > 0) {
1704                 err = ext4_group_extend_no_check(sb, o_blocks_count, add);
1705                 if (err)
1706                         goto out;
1707         }
1708
1709         if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG) &&
1710             es->s_log_groups_per_flex)
1711                 flexbg_size = 1 << es->s_log_groups_per_flex;
1712
1713         o_blocks_count = ext4_blocks_count(es);
1714         if (o_blocks_count == n_blocks_count)
1715                 goto out;
1716
1717         flex_gd = alloc_flex_gd(flexbg_size);
1718         if (flex_gd == NULL) {
1719                 err = -ENOMEM;
1720                 goto out;
1721         }
1722
1723         /* Add flex groups. Note that a regular group is a
1724          * flex group with 1 group.
1725          */
1726         while (ext4_setup_next_flex_gd(sb, flex_gd, n_blocks_count,
1727                                               flexbg_size)) {
1728                 ext4_alloc_group_tables(sb, flex_gd, flexbg_size);
1729                 err = ext4_flex_group_add(sb, resize_inode, flex_gd);
1730                 if (unlikely(err))
1731                         break;
1732         }
1733
1734 out:
1735         if (flex_gd)
1736                 free_flex_gd(flex_gd);
1737
1738         iput(resize_inode);
1739         if (test_opt(sb, DEBUG))
1740                 ext4_msg(sb, KERN_DEBUG, "resized filesystem from %llu "
1741                        "upto %llu blocks", o_blocks_count, n_blocks_count);
1742         return err;
1743 }