ext4: fix fencepost error in check for inode count overflow during resize
[muen/linux.git] / fs / ext4 / resize.c
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  *  linux/fs/ext4/resize.c
4  *
5  * Support for resizing an ext4 filesystem while it is mounted.
6  *
7  * Copyright (C) 2001, 2002 Andreas Dilger <adilger@clusterfs.com>
8  *
9  * This could probably be made into a module, because it is not often in use.
10  */
11
12
13 #define EXT4FS_DEBUG
14
15 #include <linux/errno.h>
16 #include <linux/slab.h>
17
18 #include "ext4_jbd2.h"
19
20 int ext4_resize_begin(struct super_block *sb)
21 {
22         int ret = 0;
23
24         if (!capable(CAP_SYS_RESOURCE))
25                 return -EPERM;
26
27         /*
28          * If we are not using the primary superblock/GDT copy don't resize,
29          * because the user tools have no way of handling this.  Probably a
30          * bad time to do it anyways.
31          */
32         if (EXT4_SB(sb)->s_sbh->b_blocknr !=
33             le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block)) {
34                 ext4_warning(sb, "won't resize using backup superblock at %llu",
35                         (unsigned long long)EXT4_SB(sb)->s_sbh->b_blocknr);
36                 return -EPERM;
37         }
38
39         /*
40          * We are not allowed to do online-resizing on a filesystem mounted
41          * with error, because it can destroy the filesystem easily.
42          */
43         if (EXT4_SB(sb)->s_mount_state & EXT4_ERROR_FS) {
44                 ext4_warning(sb, "There are errors in the filesystem, "
45                              "so online resizing is not allowed");
46                 return -EPERM;
47         }
48
49         if (test_and_set_bit_lock(EXT4_FLAGS_RESIZING,
50                                   &EXT4_SB(sb)->s_ext4_flags))
51                 ret = -EBUSY;
52
53         return ret;
54 }
55
56 void ext4_resize_end(struct super_block *sb)
57 {
58         clear_bit_unlock(EXT4_FLAGS_RESIZING, &EXT4_SB(sb)->s_ext4_flags);
59         smp_mb__after_atomic();
60 }
61
62 static ext4_group_t ext4_meta_bg_first_group(struct super_block *sb,
63                                              ext4_group_t group) {
64         return (group >> EXT4_DESC_PER_BLOCK_BITS(sb)) <<
65                EXT4_DESC_PER_BLOCK_BITS(sb);
66 }
67
68 static ext4_fsblk_t ext4_meta_bg_first_block_no(struct super_block *sb,
69                                              ext4_group_t group) {
70         group = ext4_meta_bg_first_group(sb, group);
71         return ext4_group_first_block_no(sb, group);
72 }
73
74 static ext4_grpblk_t ext4_group_overhead_blocks(struct super_block *sb,
75                                                 ext4_group_t group) {
76         ext4_grpblk_t overhead;
77         overhead = ext4_bg_num_gdb(sb, group);
78         if (ext4_bg_has_super(sb, group))
79                 overhead += 1 +
80                           le16_to_cpu(EXT4_SB(sb)->s_es->s_reserved_gdt_blocks);
81         return overhead;
82 }
83
84 #define outside(b, first, last) ((b) < (first) || (b) >= (last))
85 #define inside(b, first, last)  ((b) >= (first) && (b) < (last))
86
87 static int verify_group_input(struct super_block *sb,
88                               struct ext4_new_group_data *input)
89 {
90         struct ext4_sb_info *sbi = EXT4_SB(sb);
91         struct ext4_super_block *es = sbi->s_es;
92         ext4_fsblk_t start = ext4_blocks_count(es);
93         ext4_fsblk_t end = start + input->blocks_count;
94         ext4_group_t group = input->group;
95         ext4_fsblk_t itend = input->inode_table + sbi->s_itb_per_group;
96         unsigned overhead;
97         ext4_fsblk_t metaend;
98         struct buffer_head *bh = NULL;
99         ext4_grpblk_t free_blocks_count, offset;
100         int err = -EINVAL;
101
102         if (group != sbi->s_groups_count) {
103                 ext4_warning(sb, "Cannot add at group %u (only %u groups)",
104                              input->group, sbi->s_groups_count);
105                 return -EINVAL;
106         }
107
108         overhead = ext4_group_overhead_blocks(sb, group);
109         metaend = start + overhead;
110         input->free_clusters_count = free_blocks_count =
111                 input->blocks_count - 2 - overhead - sbi->s_itb_per_group;
112
113         if (test_opt(sb, DEBUG))
114                 printk(KERN_DEBUG "EXT4-fs: adding %s group %u: %u blocks "
115                        "(%d free, %u reserved)\n",
116                        ext4_bg_has_super(sb, input->group) ? "normal" :
117                        "no-super", input->group, input->blocks_count,
118                        free_blocks_count, input->reserved_blocks);
119
120         ext4_get_group_no_and_offset(sb, start, NULL, &offset);
121         if (offset != 0)
122                         ext4_warning(sb, "Last group not full");
123         else if (input->reserved_blocks > input->blocks_count / 5)
124                 ext4_warning(sb, "Reserved blocks too high (%u)",
125                              input->reserved_blocks);
126         else if (free_blocks_count < 0)
127                 ext4_warning(sb, "Bad blocks count %u",
128                              input->blocks_count);
129         else if (!(bh = sb_bread(sb, end - 1)))
130                 ext4_warning(sb, "Cannot read last block (%llu)",
131                              end - 1);
132         else if (outside(input->block_bitmap, start, end))
133                 ext4_warning(sb, "Block bitmap not in group (block %llu)",
134                              (unsigned long long)input->block_bitmap);
135         else if (outside(input->inode_bitmap, start, end))
136                 ext4_warning(sb, "Inode bitmap not in group (block %llu)",
137                              (unsigned long long)input->inode_bitmap);
138         else if (outside(input->inode_table, start, end) ||
139                  outside(itend - 1, start, end))
140                 ext4_warning(sb, "Inode table not in group (blocks %llu-%llu)",
141                              (unsigned long long)input->inode_table, itend - 1);
142         else if (input->inode_bitmap == input->block_bitmap)
143                 ext4_warning(sb, "Block bitmap same as inode bitmap (%llu)",
144                              (unsigned long long)input->block_bitmap);
145         else if (inside(input->block_bitmap, input->inode_table, itend))
146                 ext4_warning(sb, "Block bitmap (%llu) in inode table "
147                              "(%llu-%llu)",
148                              (unsigned long long)input->block_bitmap,
149                              (unsigned long long)input->inode_table, itend - 1);
150         else if (inside(input->inode_bitmap, input->inode_table, itend))
151                 ext4_warning(sb, "Inode bitmap (%llu) in inode table "
152                              "(%llu-%llu)",
153                              (unsigned long long)input->inode_bitmap,
154                              (unsigned long long)input->inode_table, itend - 1);
155         else if (inside(input->block_bitmap, start, metaend))
156                 ext4_warning(sb, "Block bitmap (%llu) in GDT table (%llu-%llu)",
157                              (unsigned long long)input->block_bitmap,
158                              start, metaend - 1);
159         else if (inside(input->inode_bitmap, start, metaend))
160                 ext4_warning(sb, "Inode bitmap (%llu) in GDT table (%llu-%llu)",
161                              (unsigned long long)input->inode_bitmap,
162                              start, metaend - 1);
163         else if (inside(input->inode_table, start, metaend) ||
164                  inside(itend - 1, start, metaend))
165                 ext4_warning(sb, "Inode table (%llu-%llu) overlaps GDT table "
166                              "(%llu-%llu)",
167                              (unsigned long long)input->inode_table,
168                              itend - 1, start, metaend - 1);
169         else
170                 err = 0;
171         brelse(bh);
172
173         return err;
174 }
175
176 /*
177  * ext4_new_flex_group_data is used by 64bit-resize interface to add a flex
178  * group each time.
179  */
180 struct ext4_new_flex_group_data {
181         struct ext4_new_group_data *groups;     /* new_group_data for groups
182                                                    in the flex group */
183         __u16 *bg_flags;                        /* block group flags of groups
184                                                    in @groups */
185         ext4_group_t count;                     /* number of groups in @groups
186                                                  */
187 };
188
189 /*
190  * alloc_flex_gd() allocates a ext4_new_flex_group_data with size of
191  * @flexbg_size.
192  *
193  * Returns NULL on failure otherwise address of the allocated structure.
194  */
195 static struct ext4_new_flex_group_data *alloc_flex_gd(unsigned long flexbg_size)
196 {
197         struct ext4_new_flex_group_data *flex_gd;
198
199         flex_gd = kmalloc(sizeof(*flex_gd), GFP_NOFS);
200         if (flex_gd == NULL)
201                 goto out3;
202
203         if (flexbg_size >= UINT_MAX / sizeof(struct ext4_new_group_data))
204                 goto out2;
205         flex_gd->count = flexbg_size;
206
207         flex_gd->groups = kmalloc(sizeof(struct ext4_new_group_data) *
208                                   flexbg_size, GFP_NOFS);
209         if (flex_gd->groups == NULL)
210                 goto out2;
211
212         flex_gd->bg_flags = kmalloc(flexbg_size * sizeof(__u16), GFP_NOFS);
213         if (flex_gd->bg_flags == NULL)
214                 goto out1;
215
216         return flex_gd;
217
218 out1:
219         kfree(flex_gd->groups);
220 out2:
221         kfree(flex_gd);
222 out3:
223         return NULL;
224 }
225
226 static void free_flex_gd(struct ext4_new_flex_group_data *flex_gd)
227 {
228         kfree(flex_gd->bg_flags);
229         kfree(flex_gd->groups);
230         kfree(flex_gd);
231 }
232
233 /*
234  * ext4_alloc_group_tables() allocates block bitmaps, inode bitmaps
235  * and inode tables for a flex group.
236  *
237  * This function is used by 64bit-resize.  Note that this function allocates
238  * group tables from the 1st group of groups contained by @flexgd, which may
239  * be a partial of a flex group.
240  *
241  * @sb: super block of fs to which the groups belongs
242  *
243  * Returns 0 on a successful allocation of the metadata blocks in the
244  * block group.
245  */
246 static int ext4_alloc_group_tables(struct super_block *sb,
247                                 struct ext4_new_flex_group_data *flex_gd,
248                                 int flexbg_size)
249 {
250         struct ext4_new_group_data *group_data = flex_gd->groups;
251         ext4_fsblk_t start_blk;
252         ext4_fsblk_t last_blk;
253         ext4_group_t src_group;
254         ext4_group_t bb_index = 0;
255         ext4_group_t ib_index = 0;
256         ext4_group_t it_index = 0;
257         ext4_group_t group;
258         ext4_group_t last_group;
259         unsigned overhead;
260         __u16 uninit_mask = (flexbg_size > 1) ? ~EXT4_BG_BLOCK_UNINIT : ~0;
261         int i;
262
263         BUG_ON(flex_gd->count == 0 || group_data == NULL);
264
265         src_group = group_data[0].group;
266         last_group  = src_group + flex_gd->count - 1;
267
268         BUG_ON((flexbg_size > 1) && ((src_group & ~(flexbg_size - 1)) !=
269                (last_group & ~(flexbg_size - 1))));
270 next_group:
271         group = group_data[0].group;
272         if (src_group >= group_data[0].group + flex_gd->count)
273                 return -ENOSPC;
274         start_blk = ext4_group_first_block_no(sb, src_group);
275         last_blk = start_blk + group_data[src_group - group].blocks_count;
276
277         overhead = ext4_group_overhead_blocks(sb, src_group);
278
279         start_blk += overhead;
280
281         /* We collect contiguous blocks as much as possible. */
282         src_group++;
283         for (; src_group <= last_group; src_group++) {
284                 overhead = ext4_group_overhead_blocks(sb, src_group);
285                 if (overhead == 0)
286                         last_blk += group_data[src_group - group].blocks_count;
287                 else
288                         break;
289         }
290
291         /* Allocate block bitmaps */
292         for (; bb_index < flex_gd->count; bb_index++) {
293                 if (start_blk >= last_blk)
294                         goto next_group;
295                 group_data[bb_index].block_bitmap = start_blk++;
296                 group = ext4_get_group_number(sb, start_blk - 1);
297                 group -= group_data[0].group;
298                 group_data[group].mdata_blocks++;
299                 flex_gd->bg_flags[group] &= uninit_mask;
300         }
301
302         /* Allocate inode bitmaps */
303         for (; ib_index < flex_gd->count; ib_index++) {
304                 if (start_blk >= last_blk)
305                         goto next_group;
306                 group_data[ib_index].inode_bitmap = start_blk++;
307                 group = ext4_get_group_number(sb, start_blk - 1);
308                 group -= group_data[0].group;
309                 group_data[group].mdata_blocks++;
310                 flex_gd->bg_flags[group] &= uninit_mask;
311         }
312
313         /* Allocate inode tables */
314         for (; it_index < flex_gd->count; it_index++) {
315                 unsigned int itb = EXT4_SB(sb)->s_itb_per_group;
316                 ext4_fsblk_t next_group_start;
317
318                 if (start_blk + itb > last_blk)
319                         goto next_group;
320                 group_data[it_index].inode_table = start_blk;
321                 group = ext4_get_group_number(sb, start_blk);
322                 next_group_start = ext4_group_first_block_no(sb, group + 1);
323                 group -= group_data[0].group;
324
325                 if (start_blk + itb > next_group_start) {
326                         flex_gd->bg_flags[group + 1] &= uninit_mask;
327                         overhead = start_blk + itb - next_group_start;
328                         group_data[group + 1].mdata_blocks += overhead;
329                         itb -= overhead;
330                 }
331
332                 group_data[group].mdata_blocks += itb;
333                 flex_gd->bg_flags[group] &= uninit_mask;
334                 start_blk += EXT4_SB(sb)->s_itb_per_group;
335         }
336
337         /* Update free clusters count to exclude metadata blocks */
338         for (i = 0; i < flex_gd->count; i++) {
339                 group_data[i].free_clusters_count -=
340                                 EXT4_NUM_B2C(EXT4_SB(sb),
341                                              group_data[i].mdata_blocks);
342         }
343
344         if (test_opt(sb, DEBUG)) {
345                 int i;
346                 group = group_data[0].group;
347
348                 printk(KERN_DEBUG "EXT4-fs: adding a flex group with "
349                        "%d groups, flexbg size is %d:\n", flex_gd->count,
350                        flexbg_size);
351
352                 for (i = 0; i < flex_gd->count; i++) {
353                         ext4_debug(
354                                "adding %s group %u: %u blocks (%d free, %d mdata blocks)\n",
355                                ext4_bg_has_super(sb, group + i) ? "normal" :
356                                "no-super", group + i,
357                                group_data[i].blocks_count,
358                                group_data[i].free_clusters_count,
359                                group_data[i].mdata_blocks);
360                 }
361         }
362         return 0;
363 }
364
365 static struct buffer_head *bclean(handle_t *handle, struct super_block *sb,
366                                   ext4_fsblk_t blk)
367 {
368         struct buffer_head *bh;
369         int err;
370
371         bh = sb_getblk(sb, blk);
372         if (unlikely(!bh))
373                 return ERR_PTR(-ENOMEM);
374         BUFFER_TRACE(bh, "get_write_access");
375         if ((err = ext4_journal_get_write_access(handle, bh))) {
376                 brelse(bh);
377                 bh = ERR_PTR(err);
378         } else {
379                 memset(bh->b_data, 0, sb->s_blocksize);
380                 set_buffer_uptodate(bh);
381         }
382
383         return bh;
384 }
385
386 /*
387  * If we have fewer than thresh credits, extend by EXT4_MAX_TRANS_DATA.
388  * If that fails, restart the transaction & regain write access for the
389  * buffer head which is used for block_bitmap modifications.
390  */
391 static int extend_or_restart_transaction(handle_t *handle, int thresh)
392 {
393         int err;
394
395         if (ext4_handle_has_enough_credits(handle, thresh))
396                 return 0;
397
398         err = ext4_journal_extend(handle, EXT4_MAX_TRANS_DATA);
399         if (err < 0)
400                 return err;
401         if (err) {
402                 err = ext4_journal_restart(handle, EXT4_MAX_TRANS_DATA);
403                 if (err)
404                         return err;
405         }
406
407         return 0;
408 }
409
410 /*
411  * set_flexbg_block_bitmap() mark clusters [@first_cluster, @last_cluster] used.
412  *
413  * Helper function for ext4_setup_new_group_blocks() which set .
414  *
415  * @sb: super block
416  * @handle: journal handle
417  * @flex_gd: flex group data
418  */
419 static int set_flexbg_block_bitmap(struct super_block *sb, handle_t *handle,
420                         struct ext4_new_flex_group_data *flex_gd,
421                         ext4_fsblk_t first_cluster, ext4_fsblk_t last_cluster)
422 {
423         struct ext4_sb_info *sbi = EXT4_SB(sb);
424         ext4_group_t count = last_cluster - first_cluster + 1;
425         ext4_group_t count2;
426
427         ext4_debug("mark clusters [%llu-%llu] used\n", first_cluster,
428                    last_cluster);
429         for (count2 = count; count > 0;
430              count -= count2, first_cluster += count2) {
431                 ext4_fsblk_t start;
432                 struct buffer_head *bh;
433                 ext4_group_t group;
434                 int err;
435
436                 group = ext4_get_group_number(sb, EXT4_C2B(sbi, first_cluster));
437                 start = EXT4_B2C(sbi, ext4_group_first_block_no(sb, group));
438                 group -= flex_gd->groups[0].group;
439
440                 count2 = EXT4_CLUSTERS_PER_GROUP(sb) - (first_cluster - start);
441                 if (count2 > count)
442                         count2 = count;
443
444                 if (flex_gd->bg_flags[group] & EXT4_BG_BLOCK_UNINIT) {
445                         BUG_ON(flex_gd->count > 1);
446                         continue;
447                 }
448
449                 err = extend_or_restart_transaction(handle, 1);
450                 if (err)
451                         return err;
452
453                 bh = sb_getblk(sb, flex_gd->groups[group].block_bitmap);
454                 if (unlikely(!bh))
455                         return -ENOMEM;
456
457                 BUFFER_TRACE(bh, "get_write_access");
458                 err = ext4_journal_get_write_access(handle, bh);
459                 if (err)
460                         return err;
461                 ext4_debug("mark block bitmap %#04llx (+%llu/%u)\n",
462                            first_cluster, first_cluster - start, count2);
463                 ext4_set_bits(bh->b_data, first_cluster - start, count2);
464
465                 err = ext4_handle_dirty_metadata(handle, NULL, bh);
466                 if (unlikely(err))
467                         return err;
468                 brelse(bh);
469         }
470
471         return 0;
472 }
473
474 /*
475  * Set up the block and inode bitmaps, and the inode table for the new groups.
476  * This doesn't need to be part of the main transaction, since we are only
477  * changing blocks outside the actual filesystem.  We still do journaling to
478  * ensure the recovery is correct in case of a failure just after resize.
479  * If any part of this fails, we simply abort the resize.
480  *
481  * setup_new_flex_group_blocks handles a flex group as follow:
482  *  1. copy super block and GDT, and initialize group tables if necessary.
483  *     In this step, we only set bits in blocks bitmaps for blocks taken by
484  *     super block and GDT.
485  *  2. allocate group tables in block bitmaps, that is, set bits in block
486  *     bitmap for blocks taken by group tables.
487  */
488 static int setup_new_flex_group_blocks(struct super_block *sb,
489                                 struct ext4_new_flex_group_data *flex_gd)
490 {
491         int group_table_count[] = {1, 1, EXT4_SB(sb)->s_itb_per_group};
492         ext4_fsblk_t start;
493         ext4_fsblk_t block;
494         struct ext4_sb_info *sbi = EXT4_SB(sb);
495         struct ext4_super_block *es = sbi->s_es;
496         struct ext4_new_group_data *group_data = flex_gd->groups;
497         __u16 *bg_flags = flex_gd->bg_flags;
498         handle_t *handle;
499         ext4_group_t group, count;
500         struct buffer_head *bh = NULL;
501         int reserved_gdb, i, j, err = 0, err2;
502         int meta_bg;
503
504         BUG_ON(!flex_gd->count || !group_data ||
505                group_data[0].group != sbi->s_groups_count);
506
507         reserved_gdb = le16_to_cpu(es->s_reserved_gdt_blocks);
508         meta_bg = ext4_has_feature_meta_bg(sb);
509
510         /* This transaction may be extended/restarted along the way */
511         handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, EXT4_MAX_TRANS_DATA);
512         if (IS_ERR(handle))
513                 return PTR_ERR(handle);
514
515         group = group_data[0].group;
516         for (i = 0; i < flex_gd->count; i++, group++) {
517                 unsigned long gdblocks;
518                 ext4_grpblk_t overhead;
519
520                 gdblocks = ext4_bg_num_gdb(sb, group);
521                 start = ext4_group_first_block_no(sb, group);
522
523                 if (meta_bg == 0 && !ext4_bg_has_super(sb, group))
524                         goto handle_itb;
525
526                 if (meta_bg == 1) {
527                         ext4_group_t first_group;
528                         first_group = ext4_meta_bg_first_group(sb, group);
529                         if (first_group != group + 1 &&
530                             first_group != group + EXT4_DESC_PER_BLOCK(sb) - 1)
531                                 goto handle_itb;
532                 }
533
534                 block = start + ext4_bg_has_super(sb, group);
535                 /* Copy all of the GDT blocks into the backup in this group */
536                 for (j = 0; j < gdblocks; j++, block++) {
537                         struct buffer_head *gdb;
538
539                         ext4_debug("update backup group %#04llx\n", block);
540                         err = extend_or_restart_transaction(handle, 1);
541                         if (err)
542                                 goto out;
543
544                         gdb = sb_getblk(sb, block);
545                         if (unlikely(!gdb)) {
546                                 err = -ENOMEM;
547                                 goto out;
548                         }
549
550                         BUFFER_TRACE(gdb, "get_write_access");
551                         err = ext4_journal_get_write_access(handle, gdb);
552                         if (err) {
553                                 brelse(gdb);
554                                 goto out;
555                         }
556                         memcpy(gdb->b_data, sbi->s_group_desc[j]->b_data,
557                                gdb->b_size);
558                         set_buffer_uptodate(gdb);
559
560                         err = ext4_handle_dirty_metadata(handle, NULL, gdb);
561                         if (unlikely(err)) {
562                                 brelse(gdb);
563                                 goto out;
564                         }
565                         brelse(gdb);
566                 }
567
568                 /* Zero out all of the reserved backup group descriptor
569                  * table blocks
570                  */
571                 if (ext4_bg_has_super(sb, group)) {
572                         err = sb_issue_zeroout(sb, gdblocks + start + 1,
573                                         reserved_gdb, GFP_NOFS);
574                         if (err)
575                                 goto out;
576                 }
577
578 handle_itb:
579                 /* Initialize group tables of the grop @group */
580                 if (!(bg_flags[i] & EXT4_BG_INODE_ZEROED))
581                         goto handle_bb;
582
583                 /* Zero out all of the inode table blocks */
584                 block = group_data[i].inode_table;
585                 ext4_debug("clear inode table blocks %#04llx -> %#04lx\n",
586                            block, sbi->s_itb_per_group);
587                 err = sb_issue_zeroout(sb, block, sbi->s_itb_per_group,
588                                        GFP_NOFS);
589                 if (err)
590                         goto out;
591
592 handle_bb:
593                 if (bg_flags[i] & EXT4_BG_BLOCK_UNINIT)
594                         goto handle_ib;
595
596                 /* Initialize block bitmap of the @group */
597                 block = group_data[i].block_bitmap;
598                 err = extend_or_restart_transaction(handle, 1);
599                 if (err)
600                         goto out;
601
602                 bh = bclean(handle, sb, block);
603                 if (IS_ERR(bh)) {
604                         err = PTR_ERR(bh);
605                         bh = NULL;
606                         goto out;
607                 }
608                 overhead = ext4_group_overhead_blocks(sb, group);
609                 if (overhead != 0) {
610                         ext4_debug("mark backup superblock %#04llx (+0)\n",
611                                    start);
612                         ext4_set_bits(bh->b_data, 0,
613                                       EXT4_NUM_B2C(sbi, overhead));
614                 }
615                 ext4_mark_bitmap_end(EXT4_B2C(sbi, group_data[i].blocks_count),
616                                      sb->s_blocksize * 8, bh->b_data);
617                 err = ext4_handle_dirty_metadata(handle, NULL, bh);
618                 if (err)
619                         goto out;
620                 brelse(bh);
621
622 handle_ib:
623                 if (bg_flags[i] & EXT4_BG_INODE_UNINIT)
624                         continue;
625
626                 /* Initialize inode bitmap of the @group */
627                 block = group_data[i].inode_bitmap;
628                 err = extend_or_restart_transaction(handle, 1);
629                 if (err)
630                         goto out;
631                 /* Mark unused entries in inode bitmap used */
632                 bh = bclean(handle, sb, block);
633                 if (IS_ERR(bh)) {
634                         err = PTR_ERR(bh);
635                         bh = NULL;
636                         goto out;
637                 }
638
639                 ext4_mark_bitmap_end(EXT4_INODES_PER_GROUP(sb),
640                                      sb->s_blocksize * 8, bh->b_data);
641                 err = ext4_handle_dirty_metadata(handle, NULL, bh);
642                 if (err)
643                         goto out;
644                 brelse(bh);
645         }
646         bh = NULL;
647
648         /* Mark group tables in block bitmap */
649         for (j = 0; j < GROUP_TABLE_COUNT; j++) {
650                 count = group_table_count[j];
651                 start = (&group_data[0].block_bitmap)[j];
652                 block = start;
653                 for (i = 1; i < flex_gd->count; i++) {
654                         block += group_table_count[j];
655                         if (block == (&group_data[i].block_bitmap)[j]) {
656                                 count += group_table_count[j];
657                                 continue;
658                         }
659                         err = set_flexbg_block_bitmap(sb, handle,
660                                                       flex_gd,
661                                                       EXT4_B2C(sbi, start),
662                                                       EXT4_B2C(sbi,
663                                                                start + count
664                                                                - 1));
665                         if (err)
666                                 goto out;
667                         count = group_table_count[j];
668                         start = (&group_data[i].block_bitmap)[j];
669                         block = start;
670                 }
671
672                 if (count) {
673                         err = set_flexbg_block_bitmap(sb, handle,
674                                                       flex_gd,
675                                                       EXT4_B2C(sbi, start),
676                                                       EXT4_B2C(sbi,
677                                                                start + count
678                                                                - 1));
679                         if (err)
680                                 goto out;
681                 }
682         }
683
684 out:
685         brelse(bh);
686         err2 = ext4_journal_stop(handle);
687         if (err2 && !err)
688                 err = err2;
689
690         return err;
691 }
692
693 /*
694  * Iterate through the groups which hold BACKUP superblock/GDT copies in an
695  * ext4 filesystem.  The counters should be initialized to 1, 5, and 7 before
696  * calling this for the first time.  In a sparse filesystem it will be the
697  * sequence of powers of 3, 5, and 7: 1, 3, 5, 7, 9, 25, 27, 49, 81, ...
698  * For a non-sparse filesystem it will be every group: 1, 2, 3, 4, ...
699  */
700 static unsigned ext4_list_backups(struct super_block *sb, unsigned *three,
701                                   unsigned *five, unsigned *seven)
702 {
703         unsigned *min = three;
704         int mult = 3;
705         unsigned ret;
706
707         if (!ext4_has_feature_sparse_super(sb)) {
708                 ret = *min;
709                 *min += 1;
710                 return ret;
711         }
712
713         if (*five < *min) {
714                 min = five;
715                 mult = 5;
716         }
717         if (*seven < *min) {
718                 min = seven;
719                 mult = 7;
720         }
721
722         ret = *min;
723         *min *= mult;
724
725         return ret;
726 }
727
728 /*
729  * Check that all of the backup GDT blocks are held in the primary GDT block.
730  * It is assumed that they are stored in group order.  Returns the number of
731  * groups in current filesystem that have BACKUPS, or -ve error code.
732  */
733 static int verify_reserved_gdb(struct super_block *sb,
734                                ext4_group_t end,
735                                struct buffer_head *primary)
736 {
737         const ext4_fsblk_t blk = primary->b_blocknr;
738         unsigned three = 1;
739         unsigned five = 5;
740         unsigned seven = 7;
741         unsigned grp;
742         __le32 *p = (__le32 *)primary->b_data;
743         int gdbackups = 0;
744
745         while ((grp = ext4_list_backups(sb, &three, &five, &seven)) < end) {
746                 if (le32_to_cpu(*p++) !=
747                     grp * EXT4_BLOCKS_PER_GROUP(sb) + blk){
748                         ext4_warning(sb, "reserved GDT %llu"
749                                      " missing grp %d (%llu)",
750                                      blk, grp,
751                                      grp *
752                                      (ext4_fsblk_t)EXT4_BLOCKS_PER_GROUP(sb) +
753                                      blk);
754                         return -EINVAL;
755                 }
756                 if (++gdbackups > EXT4_ADDR_PER_BLOCK(sb))
757                         return -EFBIG;
758         }
759
760         return gdbackups;
761 }
762
763 /*
764  * Called when we need to bring a reserved group descriptor table block into
765  * use from the resize inode.  The primary copy of the new GDT block currently
766  * is an indirect block (under the double indirect block in the resize inode).
767  * The new backup GDT blocks will be stored as leaf blocks in this indirect
768  * block, in group order.  Even though we know all the block numbers we need,
769  * we check to ensure that the resize inode has actually reserved these blocks.
770  *
771  * Don't need to update the block bitmaps because the blocks are still in use.
772  *
773  * We get all of the error cases out of the way, so that we are sure to not
774  * fail once we start modifying the data on disk, because JBD has no rollback.
775  */
776 static int add_new_gdb(handle_t *handle, struct inode *inode,
777                        ext4_group_t group)
778 {
779         struct super_block *sb = inode->i_sb;
780         struct ext4_super_block *es = EXT4_SB(sb)->s_es;
781         unsigned long gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
782         ext4_fsblk_t gdblock = EXT4_SB(sb)->s_sbh->b_blocknr + 1 + gdb_num;
783         struct buffer_head **o_group_desc, **n_group_desc;
784         struct buffer_head *dind;
785         struct buffer_head *gdb_bh;
786         int gdbackups;
787         struct ext4_iloc iloc;
788         __le32 *data;
789         int err;
790
791         if (test_opt(sb, DEBUG))
792                 printk(KERN_DEBUG
793                        "EXT4-fs: ext4_add_new_gdb: adding group block %lu\n",
794                        gdb_num);
795
796         gdb_bh = sb_bread(sb, gdblock);
797         if (!gdb_bh)
798                 return -EIO;
799
800         gdbackups = verify_reserved_gdb(sb, group, gdb_bh);
801         if (gdbackups < 0) {
802                 err = gdbackups;
803                 goto exit_bh;
804         }
805
806         data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK;
807         dind = sb_bread(sb, le32_to_cpu(*data));
808         if (!dind) {
809                 err = -EIO;
810                 goto exit_bh;
811         }
812
813         data = (__le32 *)dind->b_data;
814         if (le32_to_cpu(data[gdb_num % EXT4_ADDR_PER_BLOCK(sb)]) != gdblock) {
815                 ext4_warning(sb, "new group %u GDT block %llu not reserved",
816                              group, gdblock);
817                 err = -EINVAL;
818                 goto exit_dind;
819         }
820
821         BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access");
822         err = ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh);
823         if (unlikely(err))
824                 goto exit_dind;
825
826         BUFFER_TRACE(gdb_bh, "get_write_access");
827         err = ext4_journal_get_write_access(handle, gdb_bh);
828         if (unlikely(err))
829                 goto exit_dind;
830
831         BUFFER_TRACE(dind, "get_write_access");
832         err = ext4_journal_get_write_access(handle, dind);
833         if (unlikely(err))
834                 ext4_std_error(sb, err);
835
836         /* ext4_reserve_inode_write() gets a reference on the iloc */
837         err = ext4_reserve_inode_write(handle, inode, &iloc);
838         if (unlikely(err))
839                 goto exit_dind;
840
841         n_group_desc = ext4_kvmalloc((gdb_num + 1) *
842                                      sizeof(struct buffer_head *),
843                                      GFP_NOFS);
844         if (!n_group_desc) {
845                 err = -ENOMEM;
846                 ext4_warning(sb, "not enough memory for %lu groups",
847                              gdb_num + 1);
848                 goto exit_inode;
849         }
850
851         /*
852          * Finally, we have all of the possible failures behind us...
853          *
854          * Remove new GDT block from inode double-indirect block and clear out
855          * the new GDT block for use (which also "frees" the backup GDT blocks
856          * from the reserved inode).  We don't need to change the bitmaps for
857          * these blocks, because they are marked as in-use from being in the
858          * reserved inode, and will become GDT blocks (primary and backup).
859          */
860         data[gdb_num % EXT4_ADDR_PER_BLOCK(sb)] = 0;
861         err = ext4_handle_dirty_metadata(handle, NULL, dind);
862         if (unlikely(err)) {
863                 ext4_std_error(sb, err);
864                 goto exit_inode;
865         }
866         inode->i_blocks -= (gdbackups + 1) * sb->s_blocksize >>
867                            (9 - EXT4_SB(sb)->s_cluster_bits);
868         ext4_mark_iloc_dirty(handle, inode, &iloc);
869         memset(gdb_bh->b_data, 0, sb->s_blocksize);
870         err = ext4_handle_dirty_metadata(handle, NULL, gdb_bh);
871         if (unlikely(err)) {
872                 ext4_std_error(sb, err);
873                 goto exit_inode;
874         }
875         brelse(dind);
876
877         o_group_desc = EXT4_SB(sb)->s_group_desc;
878         memcpy(n_group_desc, o_group_desc,
879                EXT4_SB(sb)->s_gdb_count * sizeof(struct buffer_head *));
880         n_group_desc[gdb_num] = gdb_bh;
881         EXT4_SB(sb)->s_group_desc = n_group_desc;
882         EXT4_SB(sb)->s_gdb_count++;
883         kvfree(o_group_desc);
884
885         le16_add_cpu(&es->s_reserved_gdt_blocks, -1);
886         err = ext4_handle_dirty_super(handle, sb);
887         if (err)
888                 ext4_std_error(sb, err);
889
890         return err;
891
892 exit_inode:
893         kvfree(n_group_desc);
894         brelse(iloc.bh);
895 exit_dind:
896         brelse(dind);
897 exit_bh:
898         brelse(gdb_bh);
899
900         ext4_debug("leaving with error %d\n", err);
901         return err;
902 }
903
904 /*
905  * add_new_gdb_meta_bg is the sister of add_new_gdb.
906  */
907 static int add_new_gdb_meta_bg(struct super_block *sb,
908                                handle_t *handle, ext4_group_t group) {
909         ext4_fsblk_t gdblock;
910         struct buffer_head *gdb_bh;
911         struct buffer_head **o_group_desc, **n_group_desc;
912         unsigned long gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
913         int err;
914
915         gdblock = ext4_meta_bg_first_block_no(sb, group) +
916                    ext4_bg_has_super(sb, group);
917         gdb_bh = sb_bread(sb, gdblock);
918         if (!gdb_bh)
919                 return -EIO;
920         n_group_desc = ext4_kvmalloc((gdb_num + 1) *
921                                      sizeof(struct buffer_head *),
922                                      GFP_NOFS);
923         if (!n_group_desc) {
924                 err = -ENOMEM;
925                 ext4_warning(sb, "not enough memory for %lu groups",
926                              gdb_num + 1);
927                 return err;
928         }
929
930         o_group_desc = EXT4_SB(sb)->s_group_desc;
931         memcpy(n_group_desc, o_group_desc,
932                EXT4_SB(sb)->s_gdb_count * sizeof(struct buffer_head *));
933         n_group_desc[gdb_num] = gdb_bh;
934         EXT4_SB(sb)->s_group_desc = n_group_desc;
935         EXT4_SB(sb)->s_gdb_count++;
936         kvfree(o_group_desc);
937         BUFFER_TRACE(gdb_bh, "get_write_access");
938         err = ext4_journal_get_write_access(handle, gdb_bh);
939         if (unlikely(err))
940                 brelse(gdb_bh);
941         return err;
942 }
943
944 /*
945  * Called when we are adding a new group which has a backup copy of each of
946  * the GDT blocks (i.e. sparse group) and there are reserved GDT blocks.
947  * We need to add these reserved backup GDT blocks to the resize inode, so
948  * that they are kept for future resizing and not allocated to files.
949  *
950  * Each reserved backup GDT block will go into a different indirect block.
951  * The indirect blocks are actually the primary reserved GDT blocks,
952  * so we know in advance what their block numbers are.  We only get the
953  * double-indirect block to verify it is pointing to the primary reserved
954  * GDT blocks so we don't overwrite a data block by accident.  The reserved
955  * backup GDT blocks are stored in their reserved primary GDT block.
956  */
957 static int reserve_backup_gdb(handle_t *handle, struct inode *inode,
958                               ext4_group_t group)
959 {
960         struct super_block *sb = inode->i_sb;
961         int reserved_gdb =le16_to_cpu(EXT4_SB(sb)->s_es->s_reserved_gdt_blocks);
962         int cluster_bits = EXT4_SB(sb)->s_cluster_bits;
963         struct buffer_head **primary;
964         struct buffer_head *dind;
965         struct ext4_iloc iloc;
966         ext4_fsblk_t blk;
967         __le32 *data, *end;
968         int gdbackups = 0;
969         int res, i;
970         int err;
971
972         primary = kmalloc(reserved_gdb * sizeof(*primary), GFP_NOFS);
973         if (!primary)
974                 return -ENOMEM;
975
976         data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK;
977         dind = sb_bread(sb, le32_to_cpu(*data));
978         if (!dind) {
979                 err = -EIO;
980                 goto exit_free;
981         }
982
983         blk = EXT4_SB(sb)->s_sbh->b_blocknr + 1 + EXT4_SB(sb)->s_gdb_count;
984         data = (__le32 *)dind->b_data + (EXT4_SB(sb)->s_gdb_count %
985                                          EXT4_ADDR_PER_BLOCK(sb));
986         end = (__le32 *)dind->b_data + EXT4_ADDR_PER_BLOCK(sb);
987
988         /* Get each reserved primary GDT block and verify it holds backups */
989         for (res = 0; res < reserved_gdb; res++, blk++) {
990                 if (le32_to_cpu(*data) != blk) {
991                         ext4_warning(sb, "reserved block %llu"
992                                      " not at offset %ld",
993                                      blk,
994                                      (long)(data - (__le32 *)dind->b_data));
995                         err = -EINVAL;
996                         goto exit_bh;
997                 }
998                 primary[res] = sb_bread(sb, blk);
999                 if (!primary[res]) {
1000                         err = -EIO;
1001                         goto exit_bh;
1002                 }
1003                 gdbackups = verify_reserved_gdb(sb, group, primary[res]);
1004                 if (gdbackups < 0) {
1005                         brelse(primary[res]);
1006                         err = gdbackups;
1007                         goto exit_bh;
1008                 }
1009                 if (++data >= end)
1010                         data = (__le32 *)dind->b_data;
1011         }
1012
1013         for (i = 0; i < reserved_gdb; i++) {
1014                 BUFFER_TRACE(primary[i], "get_write_access");
1015                 if ((err = ext4_journal_get_write_access(handle, primary[i])))
1016                         goto exit_bh;
1017         }
1018
1019         if ((err = ext4_reserve_inode_write(handle, inode, &iloc)))
1020                 goto exit_bh;
1021
1022         /*
1023          * Finally we can add each of the reserved backup GDT blocks from
1024          * the new group to its reserved primary GDT block.
1025          */
1026         blk = group * EXT4_BLOCKS_PER_GROUP(sb);
1027         for (i = 0; i < reserved_gdb; i++) {
1028                 int err2;
1029                 data = (__le32 *)primary[i]->b_data;
1030                 /* printk("reserving backup %lu[%u] = %lu\n",
1031                        primary[i]->b_blocknr, gdbackups,
1032                        blk + primary[i]->b_blocknr); */
1033                 data[gdbackups] = cpu_to_le32(blk + primary[i]->b_blocknr);
1034                 err2 = ext4_handle_dirty_metadata(handle, NULL, primary[i]);
1035                 if (!err)
1036                         err = err2;
1037         }
1038
1039         inode->i_blocks += reserved_gdb * sb->s_blocksize >> (9 - cluster_bits);
1040         ext4_mark_iloc_dirty(handle, inode, &iloc);
1041
1042 exit_bh:
1043         while (--res >= 0)
1044                 brelse(primary[res]);
1045         brelse(dind);
1046
1047 exit_free:
1048         kfree(primary);
1049
1050         return err;
1051 }
1052
1053 /*
1054  * Update the backup copies of the ext4 metadata.  These don't need to be part
1055  * of the main resize transaction, because e2fsck will re-write them if there
1056  * is a problem (basically only OOM will cause a problem).  However, we
1057  * _should_ update the backups if possible, in case the primary gets trashed
1058  * for some reason and we need to run e2fsck from a backup superblock.  The
1059  * important part is that the new block and inode counts are in the backup
1060  * superblocks, and the location of the new group metadata in the GDT backups.
1061  *
1062  * We do not need take the s_resize_lock for this, because these
1063  * blocks are not otherwise touched by the filesystem code when it is
1064  * mounted.  We don't need to worry about last changing from
1065  * sbi->s_groups_count, because the worst that can happen is that we
1066  * do not copy the full number of backups at this time.  The resize
1067  * which changed s_groups_count will backup again.
1068  */
1069 static void update_backups(struct super_block *sb, sector_t blk_off, char *data,
1070                            int size, int meta_bg)
1071 {
1072         struct ext4_sb_info *sbi = EXT4_SB(sb);
1073         ext4_group_t last;
1074         const int bpg = EXT4_BLOCKS_PER_GROUP(sb);
1075         unsigned three = 1;
1076         unsigned five = 5;
1077         unsigned seven = 7;
1078         ext4_group_t group = 0;
1079         int rest = sb->s_blocksize - size;
1080         handle_t *handle;
1081         int err = 0, err2;
1082
1083         handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, EXT4_MAX_TRANS_DATA);
1084         if (IS_ERR(handle)) {
1085                 group = 1;
1086                 err = PTR_ERR(handle);
1087                 goto exit_err;
1088         }
1089
1090         if (meta_bg == 0) {
1091                 group = ext4_list_backups(sb, &three, &five, &seven);
1092                 last = sbi->s_groups_count;
1093         } else {
1094                 group = ext4_get_group_number(sb, blk_off) + 1;
1095                 last = (ext4_group_t)(group + EXT4_DESC_PER_BLOCK(sb) - 2);
1096         }
1097
1098         while (group < sbi->s_groups_count) {
1099                 struct buffer_head *bh;
1100                 ext4_fsblk_t backup_block;
1101
1102                 /* Out of journal space, and can't get more - abort - so sad */
1103                 if (ext4_handle_valid(handle) &&
1104                     handle->h_buffer_credits == 0 &&
1105                     ext4_journal_extend(handle, EXT4_MAX_TRANS_DATA) &&
1106                     (err = ext4_journal_restart(handle, EXT4_MAX_TRANS_DATA)))
1107                         break;
1108
1109                 if (meta_bg == 0)
1110                         backup_block = ((ext4_fsblk_t)group) * bpg + blk_off;
1111                 else
1112                         backup_block = (ext4_group_first_block_no(sb, group) +
1113                                         ext4_bg_has_super(sb, group));
1114
1115                 bh = sb_getblk(sb, backup_block);
1116                 if (unlikely(!bh)) {
1117                         err = -ENOMEM;
1118                         break;
1119                 }
1120                 ext4_debug("update metadata backup %llu(+%llu)\n",
1121                            backup_block, backup_block -
1122                            ext4_group_first_block_no(sb, group));
1123                 BUFFER_TRACE(bh, "get_write_access");
1124                 if ((err = ext4_journal_get_write_access(handle, bh)))
1125                         break;
1126                 lock_buffer(bh);
1127                 memcpy(bh->b_data, data, size);
1128                 if (rest)
1129                         memset(bh->b_data + size, 0, rest);
1130                 set_buffer_uptodate(bh);
1131                 unlock_buffer(bh);
1132                 err = ext4_handle_dirty_metadata(handle, NULL, bh);
1133                 if (unlikely(err))
1134                         ext4_std_error(sb, err);
1135                 brelse(bh);
1136
1137                 if (meta_bg == 0)
1138                         group = ext4_list_backups(sb, &three, &five, &seven);
1139                 else if (group == last)
1140                         break;
1141                 else
1142                         group = last;
1143         }
1144         if ((err2 = ext4_journal_stop(handle)) && !err)
1145                 err = err2;
1146
1147         /*
1148          * Ugh! Need to have e2fsck write the backup copies.  It is too
1149          * late to revert the resize, we shouldn't fail just because of
1150          * the backup copies (they are only needed in case of corruption).
1151          *
1152          * However, if we got here we have a journal problem too, so we
1153          * can't really start a transaction to mark the superblock.
1154          * Chicken out and just set the flag on the hope it will be written
1155          * to disk, and if not - we will simply wait until next fsck.
1156          */
1157 exit_err:
1158         if (err) {
1159                 ext4_warning(sb, "can't update backup for group %u (err %d), "
1160                              "forcing fsck on next reboot", group, err);
1161                 sbi->s_mount_state &= ~EXT4_VALID_FS;
1162                 sbi->s_es->s_state &= cpu_to_le16(~EXT4_VALID_FS);
1163                 mark_buffer_dirty(sbi->s_sbh);
1164         }
1165 }
1166
1167 /*
1168  * ext4_add_new_descs() adds @count group descriptor of groups
1169  * starting at @group
1170  *
1171  * @handle: journal handle
1172  * @sb: super block
1173  * @group: the group no. of the first group desc to be added
1174  * @resize_inode: the resize inode
1175  * @count: number of group descriptors to be added
1176  */
1177 static int ext4_add_new_descs(handle_t *handle, struct super_block *sb,
1178                               ext4_group_t group, struct inode *resize_inode,
1179                               ext4_group_t count)
1180 {
1181         struct ext4_sb_info *sbi = EXT4_SB(sb);
1182         struct ext4_super_block *es = sbi->s_es;
1183         struct buffer_head *gdb_bh;
1184         int i, gdb_off, gdb_num, err = 0;
1185         int meta_bg;
1186
1187         meta_bg = ext4_has_feature_meta_bg(sb);
1188         for (i = 0; i < count; i++, group++) {
1189                 int reserved_gdb = ext4_bg_has_super(sb, group) ?
1190                         le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
1191
1192                 gdb_off = group % EXT4_DESC_PER_BLOCK(sb);
1193                 gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
1194
1195                 /*
1196                  * We will only either add reserved group blocks to a backup group
1197                  * or remove reserved blocks for the first group in a new group block.
1198                  * Doing both would be mean more complex code, and sane people don't
1199                  * use non-sparse filesystems anymore.  This is already checked above.
1200                  */
1201                 if (gdb_off) {
1202                         gdb_bh = sbi->s_group_desc[gdb_num];
1203                         BUFFER_TRACE(gdb_bh, "get_write_access");
1204                         err = ext4_journal_get_write_access(handle, gdb_bh);
1205
1206                         if (!err && reserved_gdb && ext4_bg_num_gdb(sb, group))
1207                                 err = reserve_backup_gdb(handle, resize_inode, group);
1208                 } else if (meta_bg != 0) {
1209                         err = add_new_gdb_meta_bg(sb, handle, group);
1210                 } else {
1211                         err = add_new_gdb(handle, resize_inode, group);
1212                 }
1213                 if (err)
1214                         break;
1215         }
1216         return err;
1217 }
1218
1219 static struct buffer_head *ext4_get_bitmap(struct super_block *sb, __u64 block)
1220 {
1221         struct buffer_head *bh = sb_getblk(sb, block);
1222         if (unlikely(!bh))
1223                 return NULL;
1224         if (!bh_uptodate_or_lock(bh)) {
1225                 if (bh_submit_read(bh) < 0) {
1226                         brelse(bh);
1227                         return NULL;
1228                 }
1229         }
1230
1231         return bh;
1232 }
1233
1234 static int ext4_set_bitmap_checksums(struct super_block *sb,
1235                                      ext4_group_t group,
1236                                      struct ext4_group_desc *gdp,
1237                                      struct ext4_new_group_data *group_data)
1238 {
1239         struct buffer_head *bh;
1240
1241         if (!ext4_has_metadata_csum(sb))
1242                 return 0;
1243
1244         bh = ext4_get_bitmap(sb, group_data->inode_bitmap);
1245         if (!bh)
1246                 return -EIO;
1247         ext4_inode_bitmap_csum_set(sb, group, gdp, bh,
1248                                    EXT4_INODES_PER_GROUP(sb) / 8);
1249         brelse(bh);
1250
1251         bh = ext4_get_bitmap(sb, group_data->block_bitmap);
1252         if (!bh)
1253                 return -EIO;
1254         ext4_block_bitmap_csum_set(sb, group, gdp, bh);
1255         brelse(bh);
1256
1257         return 0;
1258 }
1259
1260 /*
1261  * ext4_setup_new_descs() will set up the group descriptor descriptors of a flex bg
1262  */
1263 static int ext4_setup_new_descs(handle_t *handle, struct super_block *sb,
1264                                 struct ext4_new_flex_group_data *flex_gd)
1265 {
1266         struct ext4_new_group_data      *group_data = flex_gd->groups;
1267         struct ext4_group_desc          *gdp;
1268         struct ext4_sb_info             *sbi = EXT4_SB(sb);
1269         struct buffer_head              *gdb_bh;
1270         ext4_group_t                    group;
1271         __u16                           *bg_flags = flex_gd->bg_flags;
1272         int                             i, gdb_off, gdb_num, err = 0;
1273
1274
1275         for (i = 0; i < flex_gd->count; i++, group_data++, bg_flags++) {
1276                 group = group_data->group;
1277
1278                 gdb_off = group % EXT4_DESC_PER_BLOCK(sb);
1279                 gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
1280
1281                 /*
1282                  * get_write_access() has been called on gdb_bh by ext4_add_new_desc().
1283                  */
1284                 gdb_bh = sbi->s_group_desc[gdb_num];
1285                 /* Update group descriptor block for new group */
1286                 gdp = (struct ext4_group_desc *)(gdb_bh->b_data +
1287                                                  gdb_off * EXT4_DESC_SIZE(sb));
1288
1289                 memset(gdp, 0, EXT4_DESC_SIZE(sb));
1290                 ext4_block_bitmap_set(sb, gdp, group_data->block_bitmap);
1291                 ext4_inode_bitmap_set(sb, gdp, group_data->inode_bitmap);
1292                 err = ext4_set_bitmap_checksums(sb, group, gdp, group_data);
1293                 if (err) {
1294                         ext4_std_error(sb, err);
1295                         break;
1296                 }
1297
1298                 ext4_inode_table_set(sb, gdp, group_data->inode_table);
1299                 ext4_free_group_clusters_set(sb, gdp,
1300                                              group_data->free_clusters_count);
1301                 ext4_free_inodes_set(sb, gdp, EXT4_INODES_PER_GROUP(sb));
1302                 if (ext4_has_group_desc_csum(sb))
1303                         ext4_itable_unused_set(sb, gdp,
1304                                                EXT4_INODES_PER_GROUP(sb));
1305                 gdp->bg_flags = cpu_to_le16(*bg_flags);
1306                 ext4_group_desc_csum_set(sb, group, gdp);
1307
1308                 err = ext4_handle_dirty_metadata(handle, NULL, gdb_bh);
1309                 if (unlikely(err)) {
1310                         ext4_std_error(sb, err);
1311                         break;
1312                 }
1313
1314                 /*
1315                  * We can allocate memory for mb_alloc based on the new group
1316                  * descriptor
1317                  */
1318                 err = ext4_mb_add_groupinfo(sb, group, gdp);
1319                 if (err)
1320                         break;
1321         }
1322         return err;
1323 }
1324
1325 /*
1326  * ext4_update_super() updates the super block so that the newly added
1327  * groups can be seen by the filesystem.
1328  *
1329  * @sb: super block
1330  * @flex_gd: new added groups
1331  */
1332 static void ext4_update_super(struct super_block *sb,
1333                              struct ext4_new_flex_group_data *flex_gd)
1334 {
1335         ext4_fsblk_t blocks_count = 0;
1336         ext4_fsblk_t free_blocks = 0;
1337         ext4_fsblk_t reserved_blocks = 0;
1338         struct ext4_new_group_data *group_data = flex_gd->groups;
1339         struct ext4_sb_info *sbi = EXT4_SB(sb);
1340         struct ext4_super_block *es = sbi->s_es;
1341         int i;
1342
1343         BUG_ON(flex_gd->count == 0 || group_data == NULL);
1344         /*
1345          * Make the new blocks and inodes valid next.  We do this before
1346          * increasing the group count so that once the group is enabled,
1347          * all of its blocks and inodes are already valid.
1348          *
1349          * We always allocate group-by-group, then block-by-block or
1350          * inode-by-inode within a group, so enabling these
1351          * blocks/inodes before the group is live won't actually let us
1352          * allocate the new space yet.
1353          */
1354         for (i = 0; i < flex_gd->count; i++) {
1355                 blocks_count += group_data[i].blocks_count;
1356                 free_blocks += EXT4_C2B(sbi, group_data[i].free_clusters_count);
1357         }
1358
1359         reserved_blocks = ext4_r_blocks_count(es) * 100;
1360         reserved_blocks = div64_u64(reserved_blocks, ext4_blocks_count(es));
1361         reserved_blocks *= blocks_count;
1362         do_div(reserved_blocks, 100);
1363
1364         ext4_blocks_count_set(es, ext4_blocks_count(es) + blocks_count);
1365         ext4_free_blocks_count_set(es, ext4_free_blocks_count(es) + free_blocks);
1366         le32_add_cpu(&es->s_inodes_count, EXT4_INODES_PER_GROUP(sb) *
1367                      flex_gd->count);
1368         le32_add_cpu(&es->s_free_inodes_count, EXT4_INODES_PER_GROUP(sb) *
1369                      flex_gd->count);
1370
1371         ext4_debug("free blocks count %llu", ext4_free_blocks_count(es));
1372         /*
1373          * We need to protect s_groups_count against other CPUs seeing
1374          * inconsistent state in the superblock.
1375          *
1376          * The precise rules we use are:
1377          *
1378          * * Writers must perform a smp_wmb() after updating all
1379          *   dependent data and before modifying the groups count
1380          *
1381          * * Readers must perform an smp_rmb() after reading the groups
1382          *   count and before reading any dependent data.
1383          *
1384          * NB. These rules can be relaxed when checking the group count
1385          * while freeing data, as we can only allocate from a block
1386          * group after serialising against the group count, and we can
1387          * only then free after serialising in turn against that
1388          * allocation.
1389          */
1390         smp_wmb();
1391
1392         /* Update the global fs size fields */
1393         sbi->s_groups_count += flex_gd->count;
1394         sbi->s_blockfile_groups = min_t(ext4_group_t, sbi->s_groups_count,
1395                         (EXT4_MAX_BLOCK_FILE_PHYS / EXT4_BLOCKS_PER_GROUP(sb)));
1396
1397         /* Update the reserved block counts only once the new group is
1398          * active. */
1399         ext4_r_blocks_count_set(es, ext4_r_blocks_count(es) +
1400                                 reserved_blocks);
1401
1402         /* Update the free space counts */
1403         percpu_counter_add(&sbi->s_freeclusters_counter,
1404                            EXT4_NUM_B2C(sbi, free_blocks));
1405         percpu_counter_add(&sbi->s_freeinodes_counter,
1406                            EXT4_INODES_PER_GROUP(sb) * flex_gd->count);
1407
1408         ext4_debug("free blocks count %llu",
1409                    percpu_counter_read(&sbi->s_freeclusters_counter));
1410         if (ext4_has_feature_flex_bg(sb) && sbi->s_log_groups_per_flex) {
1411                 ext4_group_t flex_group;
1412                 flex_group = ext4_flex_group(sbi, group_data[0].group);
1413                 atomic64_add(EXT4_NUM_B2C(sbi, free_blocks),
1414                              &sbi->s_flex_groups[flex_group].free_clusters);
1415                 atomic_add(EXT4_INODES_PER_GROUP(sb) * flex_gd->count,
1416                            &sbi->s_flex_groups[flex_group].free_inodes);
1417         }
1418
1419         /*
1420          * Update the fs overhead information
1421          */
1422         ext4_calculate_overhead(sb);
1423
1424         if (test_opt(sb, DEBUG))
1425                 printk(KERN_DEBUG "EXT4-fs: added group %u:"
1426                        "%llu blocks(%llu free %llu reserved)\n", flex_gd->count,
1427                        blocks_count, free_blocks, reserved_blocks);
1428 }
1429
1430 /* Add a flex group to an fs. Ensure we handle all possible error conditions
1431  * _before_ we start modifying the filesystem, because we cannot abort the
1432  * transaction and not have it write the data to disk.
1433  */
1434 static int ext4_flex_group_add(struct super_block *sb,
1435                                struct inode *resize_inode,
1436                                struct ext4_new_flex_group_data *flex_gd)
1437 {
1438         struct ext4_sb_info *sbi = EXT4_SB(sb);
1439         struct ext4_super_block *es = sbi->s_es;
1440         ext4_fsblk_t o_blocks_count;
1441         ext4_grpblk_t last;
1442         ext4_group_t group;
1443         handle_t *handle;
1444         unsigned reserved_gdb;
1445         int err = 0, err2 = 0, credit;
1446
1447         BUG_ON(!flex_gd->count || !flex_gd->groups || !flex_gd->bg_flags);
1448
1449         reserved_gdb = le16_to_cpu(es->s_reserved_gdt_blocks);
1450         o_blocks_count = ext4_blocks_count(es);
1451         ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
1452         BUG_ON(last);
1453
1454         err = setup_new_flex_group_blocks(sb, flex_gd);
1455         if (err)
1456                 goto exit;
1457         /*
1458          * We will always be modifying at least the superblock and  GDT
1459          * blocks.  If we are adding a group past the last current GDT block,
1460          * we will also modify the inode and the dindirect block.  If we
1461          * are adding a group with superblock/GDT backups  we will also
1462          * modify each of the reserved GDT dindirect blocks.
1463          */
1464         credit = 3;     /* sb, resize inode, resize inode dindirect */
1465         /* GDT blocks */
1466         credit += 1 + DIV_ROUND_UP(flex_gd->count, EXT4_DESC_PER_BLOCK(sb));
1467         credit += reserved_gdb; /* Reserved GDT dindirect blocks */
1468         handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, credit);
1469         if (IS_ERR(handle)) {
1470                 err = PTR_ERR(handle);
1471                 goto exit;
1472         }
1473
1474         BUFFER_TRACE(sbi->s_sbh, "get_write_access");
1475         err = ext4_journal_get_write_access(handle, sbi->s_sbh);
1476         if (err)
1477                 goto exit_journal;
1478
1479         group = flex_gd->groups[0].group;
1480         BUG_ON(group != sbi->s_groups_count);
1481         err = ext4_add_new_descs(handle, sb, group,
1482                                 resize_inode, flex_gd->count);
1483         if (err)
1484                 goto exit_journal;
1485
1486         err = ext4_setup_new_descs(handle, sb, flex_gd);
1487         if (err)
1488                 goto exit_journal;
1489
1490         ext4_update_super(sb, flex_gd);
1491
1492         err = ext4_handle_dirty_super(handle, sb);
1493
1494 exit_journal:
1495         err2 = ext4_journal_stop(handle);
1496         if (!err)
1497                 err = err2;
1498
1499         if (!err) {
1500                 int gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
1501                 int gdb_num_end = ((group + flex_gd->count - 1) /
1502                                    EXT4_DESC_PER_BLOCK(sb));
1503                 int meta_bg = ext4_has_feature_meta_bg(sb);
1504                 sector_t old_gdb = 0;
1505
1506                 update_backups(sb, sbi->s_sbh->b_blocknr, (char *)es,
1507                                sizeof(struct ext4_super_block), 0);
1508                 for (; gdb_num <= gdb_num_end; gdb_num++) {
1509                         struct buffer_head *gdb_bh;
1510
1511                         gdb_bh = sbi->s_group_desc[gdb_num];
1512                         if (old_gdb == gdb_bh->b_blocknr)
1513                                 continue;
1514                         update_backups(sb, gdb_bh->b_blocknr, gdb_bh->b_data,
1515                                        gdb_bh->b_size, meta_bg);
1516                         old_gdb = gdb_bh->b_blocknr;
1517                 }
1518         }
1519 exit:
1520         return err;
1521 }
1522
1523 static int ext4_setup_next_flex_gd(struct super_block *sb,
1524                                     struct ext4_new_flex_group_data *flex_gd,
1525                                     ext4_fsblk_t n_blocks_count,
1526                                     unsigned long flexbg_size)
1527 {
1528         struct ext4_sb_info *sbi = EXT4_SB(sb);
1529         struct ext4_super_block *es = sbi->s_es;
1530         struct ext4_new_group_data *group_data = flex_gd->groups;
1531         ext4_fsblk_t o_blocks_count;
1532         ext4_group_t n_group;
1533         ext4_group_t group;
1534         ext4_group_t last_group;
1535         ext4_grpblk_t last;
1536         ext4_grpblk_t clusters_per_group;
1537         unsigned long i;
1538
1539         clusters_per_group = EXT4_CLUSTERS_PER_GROUP(sb);
1540
1541         o_blocks_count = ext4_blocks_count(es);
1542
1543         if (o_blocks_count == n_blocks_count)
1544                 return 0;
1545
1546         ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
1547         BUG_ON(last);
1548         ext4_get_group_no_and_offset(sb, n_blocks_count - 1, &n_group, &last);
1549
1550         last_group = group | (flexbg_size - 1);
1551         if (last_group > n_group)
1552                 last_group = n_group;
1553
1554         flex_gd->count = last_group - group + 1;
1555
1556         for (i = 0; i < flex_gd->count; i++) {
1557                 int overhead;
1558
1559                 group_data[i].group = group + i;
1560                 group_data[i].blocks_count = EXT4_BLOCKS_PER_GROUP(sb);
1561                 overhead = ext4_group_overhead_blocks(sb, group + i);
1562                 group_data[i].mdata_blocks = overhead;
1563                 group_data[i].free_clusters_count = EXT4_CLUSTERS_PER_GROUP(sb);
1564                 if (ext4_has_group_desc_csum(sb)) {
1565                         flex_gd->bg_flags[i] = EXT4_BG_BLOCK_UNINIT |
1566                                                EXT4_BG_INODE_UNINIT;
1567                         if (!test_opt(sb, INIT_INODE_TABLE))
1568                                 flex_gd->bg_flags[i] |= EXT4_BG_INODE_ZEROED;
1569                 } else
1570                         flex_gd->bg_flags[i] = EXT4_BG_INODE_ZEROED;
1571         }
1572
1573         if (last_group == n_group && ext4_has_group_desc_csum(sb))
1574                 /* We need to initialize block bitmap of last group. */
1575                 flex_gd->bg_flags[i - 1] &= ~EXT4_BG_BLOCK_UNINIT;
1576
1577         if ((last_group == n_group) && (last != clusters_per_group - 1)) {
1578                 group_data[i - 1].blocks_count = EXT4_C2B(sbi, last + 1);
1579                 group_data[i - 1].free_clusters_count -= clusters_per_group -
1580                                                        last - 1;
1581         }
1582
1583         return 1;
1584 }
1585
1586 /* Add group descriptor data to an existing or new group descriptor block.
1587  * Ensure we handle all possible error conditions _before_ we start modifying
1588  * the filesystem, because we cannot abort the transaction and not have it
1589  * write the data to disk.
1590  *
1591  * If we are on a GDT block boundary, we need to get the reserved GDT block.
1592  * Otherwise, we may need to add backup GDT blocks for a sparse group.
1593  *
1594  * We only need to hold the superblock lock while we are actually adding
1595  * in the new group's counts to the superblock.  Prior to that we have
1596  * not really "added" the group at all.  We re-check that we are still
1597  * adding in the last group in case things have changed since verifying.
1598  */
1599 int ext4_group_add(struct super_block *sb, struct ext4_new_group_data *input)
1600 {
1601         struct ext4_new_flex_group_data flex_gd;
1602         struct ext4_sb_info *sbi = EXT4_SB(sb);
1603         struct ext4_super_block *es = sbi->s_es;
1604         int reserved_gdb = ext4_bg_has_super(sb, input->group) ?
1605                 le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
1606         struct inode *inode = NULL;
1607         int gdb_off;
1608         int err;
1609         __u16 bg_flags = 0;
1610
1611         gdb_off = input->group % EXT4_DESC_PER_BLOCK(sb);
1612
1613         if (gdb_off == 0 && !ext4_has_feature_sparse_super(sb)) {
1614                 ext4_warning(sb, "Can't resize non-sparse filesystem further");
1615                 return -EPERM;
1616         }
1617
1618         if (ext4_blocks_count(es) + input->blocks_count <
1619             ext4_blocks_count(es)) {
1620                 ext4_warning(sb, "blocks_count overflow");
1621                 return -EINVAL;
1622         }
1623
1624         if (le32_to_cpu(es->s_inodes_count) + EXT4_INODES_PER_GROUP(sb) <
1625             le32_to_cpu(es->s_inodes_count)) {
1626                 ext4_warning(sb, "inodes_count overflow");
1627                 return -EINVAL;
1628         }
1629
1630         if (reserved_gdb || gdb_off == 0) {
1631                 if (ext4_has_feature_resize_inode(sb) ||
1632                     !le16_to_cpu(es->s_reserved_gdt_blocks)) {
1633                         ext4_warning(sb,
1634                                      "No reserved GDT blocks, can't resize");
1635                         return -EPERM;
1636                 }
1637                 inode = ext4_iget(sb, EXT4_RESIZE_INO);
1638                 if (IS_ERR(inode)) {
1639                         ext4_warning(sb, "Error opening resize inode");
1640                         return PTR_ERR(inode);
1641                 }
1642         }
1643
1644
1645         err = verify_group_input(sb, input);
1646         if (err)
1647                 goto out;
1648
1649         err = ext4_alloc_flex_bg_array(sb, input->group + 1);
1650         if (err)
1651                 goto out;
1652
1653         err = ext4_mb_alloc_groupinfo(sb, input->group + 1);
1654         if (err)
1655                 goto out;
1656
1657         flex_gd.count = 1;
1658         flex_gd.groups = input;
1659         flex_gd.bg_flags = &bg_flags;
1660         err = ext4_flex_group_add(sb, inode, &flex_gd);
1661 out:
1662         iput(inode);
1663         return err;
1664 } /* ext4_group_add */
1665
1666 /*
1667  * extend a group without checking assuming that checking has been done.
1668  */
1669 static int ext4_group_extend_no_check(struct super_block *sb,
1670                                       ext4_fsblk_t o_blocks_count, ext4_grpblk_t add)
1671 {
1672         struct ext4_super_block *es = EXT4_SB(sb)->s_es;
1673         handle_t *handle;
1674         int err = 0, err2;
1675
1676         /* We will update the superblock, one block bitmap, and
1677          * one group descriptor via ext4_group_add_blocks().
1678          */
1679         handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, 3);
1680         if (IS_ERR(handle)) {
1681                 err = PTR_ERR(handle);
1682                 ext4_warning(sb, "error %d on journal start", err);
1683                 return err;
1684         }
1685
1686         BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access");
1687         err = ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh);
1688         if (err) {
1689                 ext4_warning(sb, "error %d on journal write access", err);
1690                 goto errout;
1691         }
1692
1693         ext4_blocks_count_set(es, o_blocks_count + add);
1694         ext4_free_blocks_count_set(es, ext4_free_blocks_count(es) + add);
1695         ext4_debug("freeing blocks %llu through %llu\n", o_blocks_count,
1696                    o_blocks_count + add);
1697         /* We add the blocks to the bitmap and set the group need init bit */
1698         err = ext4_group_add_blocks(handle, sb, o_blocks_count, add);
1699         if (err)
1700                 goto errout;
1701         ext4_handle_dirty_super(handle, sb);
1702         ext4_debug("freed blocks %llu through %llu\n", o_blocks_count,
1703                    o_blocks_count + add);
1704 errout:
1705         err2 = ext4_journal_stop(handle);
1706         if (err2 && !err)
1707                 err = err2;
1708
1709         if (!err) {
1710                 if (test_opt(sb, DEBUG))
1711                         printk(KERN_DEBUG "EXT4-fs: extended group to %llu "
1712                                "blocks\n", ext4_blocks_count(es));
1713                 update_backups(sb, EXT4_SB(sb)->s_sbh->b_blocknr,
1714                                (char *)es, sizeof(struct ext4_super_block), 0);
1715         }
1716         return err;
1717 }
1718
1719 /*
1720  * Extend the filesystem to the new number of blocks specified.  This entry
1721  * point is only used to extend the current filesystem to the end of the last
1722  * existing group.  It can be accessed via ioctl, or by "remount,resize=<size>"
1723  * for emergencies (because it has no dependencies on reserved blocks).
1724  *
1725  * If we _really_ wanted, we could use default values to call ext4_group_add()
1726  * allow the "remount" trick to work for arbitrary resizing, assuming enough
1727  * GDT blocks are reserved to grow to the desired size.
1728  */
1729 int ext4_group_extend(struct super_block *sb, struct ext4_super_block *es,
1730                       ext4_fsblk_t n_blocks_count)
1731 {
1732         ext4_fsblk_t o_blocks_count;
1733         ext4_grpblk_t last;
1734         ext4_grpblk_t add;
1735         struct buffer_head *bh;
1736         int err;
1737         ext4_group_t group;
1738
1739         o_blocks_count = ext4_blocks_count(es);
1740
1741         if (test_opt(sb, DEBUG))
1742                 ext4_msg(sb, KERN_DEBUG,
1743                          "extending last group from %llu to %llu blocks",
1744                          o_blocks_count, n_blocks_count);
1745
1746         if (n_blocks_count == 0 || n_blocks_count == o_blocks_count)
1747                 return 0;
1748
1749         if (n_blocks_count > (sector_t)(~0ULL) >> (sb->s_blocksize_bits - 9)) {
1750                 ext4_msg(sb, KERN_ERR,
1751                          "filesystem too large to resize to %llu blocks safely",
1752                          n_blocks_count);
1753                 if (sizeof(sector_t) < 8)
1754                         ext4_warning(sb, "CONFIG_LBDAF not enabled");
1755                 return -EINVAL;
1756         }
1757
1758         if (n_blocks_count < o_blocks_count) {
1759                 ext4_warning(sb, "can't shrink FS - resize aborted");
1760                 return -EINVAL;
1761         }
1762
1763         /* Handle the remaining blocks in the last group only. */
1764         ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
1765
1766         if (last == 0) {
1767                 ext4_warning(sb, "need to use ext2online to resize further");
1768                 return -EPERM;
1769         }
1770
1771         add = EXT4_BLOCKS_PER_GROUP(sb) - last;
1772
1773         if (o_blocks_count + add < o_blocks_count) {
1774                 ext4_warning(sb, "blocks_count overflow");
1775                 return -EINVAL;
1776         }
1777
1778         if (o_blocks_count + add > n_blocks_count)
1779                 add = n_blocks_count - o_blocks_count;
1780
1781         if (o_blocks_count + add < n_blocks_count)
1782                 ext4_warning(sb, "will only finish group (%llu blocks, %u new)",
1783                              o_blocks_count + add, add);
1784
1785         /* See if the device is actually as big as what was requested */
1786         bh = sb_bread(sb, o_blocks_count + add - 1);
1787         if (!bh) {
1788                 ext4_warning(sb, "can't read last block, resize aborted");
1789                 return -ENOSPC;
1790         }
1791         brelse(bh);
1792
1793         err = ext4_group_extend_no_check(sb, o_blocks_count, add);
1794         return err;
1795 } /* ext4_group_extend */
1796
1797
1798 static int num_desc_blocks(struct super_block *sb, ext4_group_t groups)
1799 {
1800         return (groups + EXT4_DESC_PER_BLOCK(sb) - 1) / EXT4_DESC_PER_BLOCK(sb);
1801 }
1802
1803 /*
1804  * Release the resize inode and drop the resize_inode feature if there
1805  * are no more reserved gdt blocks, and then convert the file system
1806  * to enable meta_bg
1807  */
1808 static int ext4_convert_meta_bg(struct super_block *sb, struct inode *inode)
1809 {
1810         handle_t *handle;
1811         struct ext4_sb_info *sbi = EXT4_SB(sb);
1812         struct ext4_super_block *es = sbi->s_es;
1813         struct ext4_inode_info *ei = EXT4_I(inode);
1814         ext4_fsblk_t nr;
1815         int i, ret, err = 0;
1816         int credits = 1;
1817
1818         ext4_msg(sb, KERN_INFO, "Converting file system to meta_bg");
1819         if (inode) {
1820                 if (es->s_reserved_gdt_blocks) {
1821                         ext4_error(sb, "Unexpected non-zero "
1822                                    "s_reserved_gdt_blocks");
1823                         return -EPERM;
1824                 }
1825
1826                 /* Do a quick sanity check of the resize inode */
1827                 if (inode->i_blocks != 1 << (inode->i_blkbits -
1828                                              (9 - sbi->s_cluster_bits)))
1829                         goto invalid_resize_inode;
1830                 for (i = 0; i < EXT4_N_BLOCKS; i++) {
1831                         if (i == EXT4_DIND_BLOCK) {
1832                                 if (ei->i_data[i])
1833                                         continue;
1834                                 else
1835                                         goto invalid_resize_inode;
1836                         }
1837                         if (ei->i_data[i])
1838                                 goto invalid_resize_inode;
1839                 }
1840                 credits += 3;   /* block bitmap, bg descriptor, resize inode */
1841         }
1842
1843         handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, credits);
1844         if (IS_ERR(handle))
1845                 return PTR_ERR(handle);
1846
1847         BUFFER_TRACE(sbi->s_sbh, "get_write_access");
1848         err = ext4_journal_get_write_access(handle, sbi->s_sbh);
1849         if (err)
1850                 goto errout;
1851
1852         ext4_clear_feature_resize_inode(sb);
1853         ext4_set_feature_meta_bg(sb);
1854         sbi->s_es->s_first_meta_bg =
1855                 cpu_to_le32(num_desc_blocks(sb, sbi->s_groups_count));
1856
1857         err = ext4_handle_dirty_super(handle, sb);
1858         if (err) {
1859                 ext4_std_error(sb, err);
1860                 goto errout;
1861         }
1862
1863         if (inode) {
1864                 nr = le32_to_cpu(ei->i_data[EXT4_DIND_BLOCK]);
1865                 ext4_free_blocks(handle, inode, NULL, nr, 1,
1866                                  EXT4_FREE_BLOCKS_METADATA |
1867                                  EXT4_FREE_BLOCKS_FORGET);
1868                 ei->i_data[EXT4_DIND_BLOCK] = 0;
1869                 inode->i_blocks = 0;
1870
1871                 err = ext4_mark_inode_dirty(handle, inode);
1872                 if (err)
1873                         ext4_std_error(sb, err);
1874         }
1875
1876 errout:
1877         ret = ext4_journal_stop(handle);
1878         if (!err)
1879                 err = ret;
1880         return ret;
1881
1882 invalid_resize_inode:
1883         ext4_error(sb, "corrupted/inconsistent resize inode");
1884         return -EINVAL;
1885 }
1886
1887 /*
1888  * ext4_resize_fs() resizes a fs to new size specified by @n_blocks_count
1889  *
1890  * @sb: super block of the fs to be resized
1891  * @n_blocks_count: the number of blocks resides in the resized fs
1892  */
1893 int ext4_resize_fs(struct super_block *sb, ext4_fsblk_t n_blocks_count)
1894 {
1895         struct ext4_new_flex_group_data *flex_gd = NULL;
1896         struct ext4_sb_info *sbi = EXT4_SB(sb);
1897         struct ext4_super_block *es = sbi->s_es;
1898         struct buffer_head *bh;
1899         struct inode *resize_inode = NULL;
1900         ext4_grpblk_t add, offset;
1901         unsigned long n_desc_blocks;
1902         unsigned long o_desc_blocks;
1903         ext4_group_t o_group;
1904         ext4_group_t n_group;
1905         ext4_fsblk_t o_blocks_count;
1906         ext4_fsblk_t n_blocks_count_retry = 0;
1907         unsigned long last_update_time = 0;
1908         int err = 0, flexbg_size = 1 << sbi->s_log_groups_per_flex;
1909         int meta_bg;
1910
1911         /* See if the device is actually as big as what was requested */
1912         bh = sb_bread(sb, n_blocks_count - 1);
1913         if (!bh) {
1914                 ext4_warning(sb, "can't read last block, resize aborted");
1915                 return -ENOSPC;
1916         }
1917         brelse(bh);
1918
1919 retry:
1920         o_blocks_count = ext4_blocks_count(es);
1921
1922         ext4_msg(sb, KERN_INFO, "resizing filesystem from %llu "
1923                  "to %llu blocks", o_blocks_count, n_blocks_count);
1924
1925         if (n_blocks_count < o_blocks_count) {
1926                 /* On-line shrinking not supported */
1927                 ext4_warning(sb, "can't shrink FS - resize aborted");
1928                 return -EINVAL;
1929         }
1930
1931         if (n_blocks_count == o_blocks_count)
1932                 /* Nothing need to do */
1933                 return 0;
1934
1935         n_group = ext4_get_group_number(sb, n_blocks_count - 1);
1936         if (n_group >= (0xFFFFFFFFUL / EXT4_INODES_PER_GROUP(sb))) {
1937                 ext4_warning(sb, "resize would cause inodes_count overflow");
1938                 return -EINVAL;
1939         }
1940         ext4_get_group_no_and_offset(sb, o_blocks_count - 1, &o_group, &offset);
1941
1942         n_desc_blocks = num_desc_blocks(sb, n_group + 1);
1943         o_desc_blocks = num_desc_blocks(sb, sbi->s_groups_count);
1944
1945         meta_bg = ext4_has_feature_meta_bg(sb);
1946
1947         if (ext4_has_feature_resize_inode(sb)) {
1948                 if (meta_bg) {
1949                         ext4_error(sb, "resize_inode and meta_bg enabled "
1950                                    "simultaneously");
1951                         return -EINVAL;
1952                 }
1953                 if (n_desc_blocks > o_desc_blocks +
1954                     le16_to_cpu(es->s_reserved_gdt_blocks)) {
1955                         n_blocks_count_retry = n_blocks_count;
1956                         n_desc_blocks = o_desc_blocks +
1957                                 le16_to_cpu(es->s_reserved_gdt_blocks);
1958                         n_group = n_desc_blocks * EXT4_DESC_PER_BLOCK(sb);
1959                         n_blocks_count = (ext4_fsblk_t)n_group *
1960                                 EXT4_BLOCKS_PER_GROUP(sb);
1961                         n_group--; /* set to last group number */
1962                 }
1963
1964                 if (!resize_inode)
1965                         resize_inode = ext4_iget(sb, EXT4_RESIZE_INO);
1966                 if (IS_ERR(resize_inode)) {
1967                         ext4_warning(sb, "Error opening resize inode");
1968                         return PTR_ERR(resize_inode);
1969                 }
1970         }
1971
1972         if ((!resize_inode && !meta_bg) || n_blocks_count == o_blocks_count) {
1973                 err = ext4_convert_meta_bg(sb, resize_inode);
1974                 if (err)
1975                         goto out;
1976                 if (resize_inode) {
1977                         iput(resize_inode);
1978                         resize_inode = NULL;
1979                 }
1980                 if (n_blocks_count_retry) {
1981                         n_blocks_count = n_blocks_count_retry;
1982                         n_blocks_count_retry = 0;
1983                         goto retry;
1984                 }
1985         }
1986
1987         /* extend the last group */
1988         if (n_group == o_group)
1989                 add = n_blocks_count - o_blocks_count;
1990         else
1991                 add = EXT4_C2B(sbi, EXT4_CLUSTERS_PER_GROUP(sb) - (offset + 1));
1992         if (add > 0) {
1993                 err = ext4_group_extend_no_check(sb, o_blocks_count, add);
1994                 if (err)
1995                         goto out;
1996         }
1997
1998         if (ext4_blocks_count(es) == n_blocks_count)
1999                 goto out;
2000
2001         err = ext4_alloc_flex_bg_array(sb, n_group + 1);
2002         if (err)
2003                 return err;
2004
2005         err = ext4_mb_alloc_groupinfo(sb, n_group + 1);
2006         if (err)
2007                 goto out;
2008
2009         flex_gd = alloc_flex_gd(flexbg_size);
2010         if (flex_gd == NULL) {
2011                 err = -ENOMEM;
2012                 goto out;
2013         }
2014
2015         /* Add flex groups. Note that a regular group is a
2016          * flex group with 1 group.
2017          */
2018         while (ext4_setup_next_flex_gd(sb, flex_gd, n_blocks_count,
2019                                               flexbg_size)) {
2020                 if (jiffies - last_update_time > HZ * 10) {
2021                         if (last_update_time)
2022                                 ext4_msg(sb, KERN_INFO,
2023                                          "resized to %llu blocks",
2024                                          ext4_blocks_count(es));
2025                         last_update_time = jiffies;
2026                 }
2027                 if (ext4_alloc_group_tables(sb, flex_gd, flexbg_size) != 0)
2028                         break;
2029                 err = ext4_flex_group_add(sb, resize_inode, flex_gd);
2030                 if (unlikely(err))
2031                         break;
2032         }
2033
2034         if (!err && n_blocks_count_retry) {
2035                 n_blocks_count = n_blocks_count_retry;
2036                 n_blocks_count_retry = 0;
2037                 free_flex_gd(flex_gd);
2038                 flex_gd = NULL;
2039                 goto retry;
2040         }
2041
2042 out:
2043         if (flex_gd)
2044                 free_flex_gd(flex_gd);
2045         if (resize_inode != NULL)
2046                 iput(resize_inode);
2047         ext4_msg(sb, KERN_INFO, "resized filesystem to %llu", n_blocks_count);
2048         return err;
2049 }