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Linux/fs/ext4/resize.c

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  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 static ext4_group_t ext4_meta_bg_first_group(struct super_block *sb,
 49                                              ext4_group_t group) {
 50         return (group >> EXT4_DESC_PER_BLOCK_BITS(sb)) <<
 51                EXT4_DESC_PER_BLOCK_BITS(sb);
 52 }
 53 
 54 static ext4_fsblk_t ext4_meta_bg_first_block_no(struct super_block *sb,
 55                                              ext4_group_t group) {
 56         group = ext4_meta_bg_first_group(sb, group);
 57         return ext4_group_first_block_no(sb, group);
 58 }
 59 
 60 static ext4_grpblk_t ext4_group_overhead_blocks(struct super_block *sb,
 61                                                 ext4_group_t group) {
 62         ext4_grpblk_t overhead;
 63         overhead = ext4_bg_num_gdb(sb, group);
 64         if (ext4_bg_has_super(sb, group))
 65                 overhead += 1 +
 66                           le16_to_cpu(EXT4_SB(sb)->s_es->s_reserved_gdt_blocks);
 67         return overhead;
 68 }
 69 
 70 #define outside(b, first, last) ((b) < (first) || (b) >= (last))
 71 #define inside(b, first, last)  ((b) >= (first) && (b) < (last))
 72 
 73 static int verify_group_input(struct super_block *sb,
 74                               struct ext4_new_group_data *input)
 75 {
 76         struct ext4_sb_info *sbi = EXT4_SB(sb);
 77         struct ext4_super_block *es = sbi->s_es;
 78         ext4_fsblk_t start = ext4_blocks_count(es);
 79         ext4_fsblk_t end = start + input->blocks_count;
 80         ext4_group_t group = input->group;
 81         ext4_fsblk_t itend = input->inode_table + sbi->s_itb_per_group;
 82         unsigned overhead;
 83         ext4_fsblk_t metaend;
 84         struct buffer_head *bh = NULL;
 85         ext4_grpblk_t free_blocks_count, offset;
 86         int err = -EINVAL;
 87 
 88         if (group != sbi->s_groups_count) {
 89                 ext4_warning(sb, "Cannot add at group %u (only %u groups)",
 90                              input->group, sbi->s_groups_count);
 91                 return -EINVAL;
 92         }
 93 
 94         overhead = ext4_group_overhead_blocks(sb, group);
 95         metaend = start + overhead;
 96         input->free_blocks_count = free_blocks_count =
 97                 input->blocks_count - 2 - overhead - sbi->s_itb_per_group;
 98 
 99         if (test_opt(sb, DEBUG))
100                 printk(KERN_DEBUG "EXT4-fs: adding %s group %u: %u blocks "
101                        "(%d free, %u reserved)\n",
102                        ext4_bg_has_super(sb, input->group) ? "normal" :
103                        "no-super", input->group, input->blocks_count,
104                        free_blocks_count, input->reserved_blocks);
105 
106         ext4_get_group_no_and_offset(sb, start, NULL, &offset);
107         if (offset != 0)
108                         ext4_warning(sb, "Last group not full");
109         else if (input->reserved_blocks > input->blocks_count / 5)
110                 ext4_warning(sb, "Reserved blocks too high (%u)",
111                              input->reserved_blocks);
112         else if (free_blocks_count < 0)
113                 ext4_warning(sb, "Bad blocks count %u",
114                              input->blocks_count);
115         else if (!(bh = sb_bread(sb, end - 1)))
116                 ext4_warning(sb, "Cannot read last block (%llu)",
117                              end - 1);
118         else if (outside(input->block_bitmap, start, end))
119                 ext4_warning(sb, "Block bitmap not in group (block %llu)",
120                              (unsigned long long)input->block_bitmap);
121         else if (outside(input->inode_bitmap, start, end))
122                 ext4_warning(sb, "Inode bitmap not in group (block %llu)",
123                              (unsigned long long)input->inode_bitmap);
124         else if (outside(input->inode_table, start, end) ||
125                  outside(itend - 1, start, end))
126                 ext4_warning(sb, "Inode table not in group (blocks %llu-%llu)",
127                              (unsigned long long)input->inode_table, itend - 1);
128         else if (input->inode_bitmap == input->block_bitmap)
129                 ext4_warning(sb, "Block bitmap same as inode bitmap (%llu)",
130                              (unsigned long long)input->block_bitmap);
131         else if (inside(input->block_bitmap, input->inode_table, itend))
132                 ext4_warning(sb, "Block bitmap (%llu) in inode table "
133                              "(%llu-%llu)",
134                              (unsigned long long)input->block_bitmap,
135                              (unsigned long long)input->inode_table, itend - 1);
136         else if (inside(input->inode_bitmap, input->inode_table, itend))
137                 ext4_warning(sb, "Inode bitmap (%llu) in inode table "
138                              "(%llu-%llu)",
139                              (unsigned long long)input->inode_bitmap,
140                              (unsigned long long)input->inode_table, itend - 1);
141         else if (inside(input->block_bitmap, start, metaend))
142                 ext4_warning(sb, "Block bitmap (%llu) in GDT table (%llu-%llu)",
143                              (unsigned long long)input->block_bitmap,
144                              start, metaend - 1);
145         else if (inside(input->inode_bitmap, start, metaend))
146                 ext4_warning(sb, "Inode bitmap (%llu) in GDT table (%llu-%llu)",
147                              (unsigned long long)input->inode_bitmap,
148                              start, metaend - 1);
149         else if (inside(input->inode_table, start, metaend) ||
150                  inside(itend - 1, start, metaend))
151                 ext4_warning(sb, "Inode table (%llu-%llu) overlaps GDT table "
152                              "(%llu-%llu)",
153                              (unsigned long long)input->inode_table,
154                              itend - 1, start, metaend - 1);
155         else
156                 err = 0;
157         brelse(bh);
158 
159         return err;
160 }
161 
162 /*
163  * ext4_new_flex_group_data is used by 64bit-resize interface to add a flex
164  * group each time.
165  */
166 struct ext4_new_flex_group_data {
167         struct ext4_new_group_data *groups;     /* new_group_data for groups
168                                                    in the flex group */
169         __u16 *bg_flags;                        /* block group flags of groups
170                                                    in @groups */
171         ext4_group_t count;                     /* number of groups in @groups
172                                                  */
173 };
174 
175 /*
176  * alloc_flex_gd() allocates a ext4_new_flex_group_data with size of
177  * @flexbg_size.
178  *
179  * Returns NULL on failure otherwise address of the allocated structure.
180  */
181 static struct ext4_new_flex_group_data *alloc_flex_gd(unsigned long flexbg_size)
182 {
183         struct ext4_new_flex_group_data *flex_gd;
184 
185         flex_gd = kmalloc(sizeof(*flex_gd), GFP_NOFS);
186         if (flex_gd == NULL)
187                 goto out3;
188 
189         if (flexbg_size >= UINT_MAX / sizeof(struct ext4_new_flex_group_data))
190                 goto out2;
191         flex_gd->count = flexbg_size;
192 
193         flex_gd->groups = kmalloc(sizeof(struct ext4_new_group_data) *
194                                   flexbg_size, GFP_NOFS);
195         if (flex_gd->groups == NULL)
196                 goto out2;
197 
198         flex_gd->bg_flags = kmalloc(flexbg_size * sizeof(__u16), GFP_NOFS);
199         if (flex_gd->bg_flags == NULL)
200                 goto out1;
201 
202         return flex_gd;
203 
204 out1:
205         kfree(flex_gd->groups);
206 out2:
207         kfree(flex_gd);
208 out3:
209         return NULL;
210 }
211 
212 static void free_flex_gd(struct ext4_new_flex_group_data *flex_gd)
213 {
214         kfree(flex_gd->bg_flags);
215         kfree(flex_gd->groups);
216         kfree(flex_gd);
217 }
218 
219 /*
220  * ext4_alloc_group_tables() allocates block bitmaps, inode bitmaps
221  * and inode tables for a flex group.
222  *
223  * This function is used by 64bit-resize.  Note that this function allocates
224  * group tables from the 1st group of groups contained by @flexgd, which may
225  * be a partial of a flex group.
226  *
227  * @sb: super block of fs to which the groups belongs
228  *
229  * Returns 0 on a successful allocation of the metadata blocks in the
230  * block group.
231  */
232 static int ext4_alloc_group_tables(struct super_block *sb,
233                                 struct ext4_new_flex_group_data *flex_gd,
234                                 int flexbg_size)
235 {
236         struct ext4_new_group_data *group_data = flex_gd->groups;
237         ext4_fsblk_t start_blk;
238         ext4_fsblk_t last_blk;
239         ext4_group_t src_group;
240         ext4_group_t bb_index = 0;
241         ext4_group_t ib_index = 0;
242         ext4_group_t it_index = 0;
243         ext4_group_t group;
244         ext4_group_t last_group;
245         unsigned overhead;
246         __u16 uninit_mask = (flexbg_size > 1) ? ~EXT4_BG_BLOCK_UNINIT : ~0;
247 
248         BUG_ON(flex_gd->count == 0 || group_data == NULL);
249 
250         src_group = group_data[0].group;
251         last_group  = src_group + flex_gd->count - 1;
252 
253         BUG_ON((flexbg_size > 1) && ((src_group & ~(flexbg_size - 1)) !=
254                (last_group & ~(flexbg_size - 1))));
255 next_group:
256         group = group_data[0].group;
257         if (src_group >= group_data[0].group + flex_gd->count)
258                 return -ENOSPC;
259         start_blk = ext4_group_first_block_no(sb, src_group);
260         last_blk = start_blk + group_data[src_group - group].blocks_count;
261 
262         overhead = ext4_group_overhead_blocks(sb, src_group);
263 
264         start_blk += overhead;
265 
266         /* We collect contiguous blocks as much as possible. */
267         src_group++;
268         for (; src_group <= last_group; src_group++) {
269                 overhead = ext4_group_overhead_blocks(sb, src_group);
270                 if (overhead == 0)
271                         last_blk += group_data[src_group - group].blocks_count;
272                 else
273                         break;
274         }
275 
276         /* Allocate block bitmaps */
277         for (; bb_index < flex_gd->count; bb_index++) {
278                 if (start_blk >= last_blk)
279                         goto next_group;
280                 group_data[bb_index].block_bitmap = start_blk++;
281                 group = ext4_get_group_number(sb, start_blk - 1);
282                 group -= group_data[0].group;
283                 group_data[group].free_blocks_count--;
284                 flex_gd->bg_flags[group] &= uninit_mask;
285         }
286 
287         /* Allocate inode bitmaps */
288         for (; ib_index < flex_gd->count; ib_index++) {
289                 if (start_blk >= last_blk)
290                         goto next_group;
291                 group_data[ib_index].inode_bitmap = start_blk++;
292                 group = ext4_get_group_number(sb, start_blk - 1);
293                 group -= group_data[0].group;
294                 group_data[group].free_blocks_count--;
295                 flex_gd->bg_flags[group] &= uninit_mask;
296         }
297 
298         /* Allocate inode tables */
299         for (; it_index < flex_gd->count; it_index++) {
300                 unsigned int itb = EXT4_SB(sb)->s_itb_per_group;
301                 ext4_fsblk_t next_group_start;
302 
303                 if (start_blk + itb > last_blk)
304                         goto next_group;
305                 group_data[it_index].inode_table = start_blk;
306                 group = ext4_get_group_number(sb, start_blk);
307                 next_group_start = ext4_group_first_block_no(sb, group + 1);
308                 group -= group_data[0].group;
309 
310                 if (start_blk + itb > next_group_start) {
311                         flex_gd->bg_flags[group + 1] &= uninit_mask;
312                         overhead = start_blk + itb - next_group_start;
313                         group_data[group + 1].free_blocks_count -= overhead;
314                         itb -= overhead;
315                 }
316 
317                 group_data[group].free_blocks_count -= itb;
318                 flex_gd->bg_flags[group] &= uninit_mask;
319                 start_blk += EXT4_SB(sb)->s_itb_per_group;
320         }
321 
322         if (test_opt(sb, DEBUG)) {
323                 int i;
324                 group = group_data[0].group;
325 
326                 printk(KERN_DEBUG "EXT4-fs: adding a flex group with "
327                        "%d groups, flexbg size is %d:\n", flex_gd->count,
328                        flexbg_size);
329 
330                 for (i = 0; i < flex_gd->count; i++) {
331                         printk(KERN_DEBUG "adding %s group %u: %u "
332                                "blocks (%d free)\n",
333                                ext4_bg_has_super(sb, group + i) ? "normal" :
334                                "no-super", group + i,
335                                group_data[i].blocks_count,
336                                group_data[i].free_blocks_count);
337                 }
338         }
339         return 0;
340 }
341 
342 static struct buffer_head *bclean(handle_t *handle, struct super_block *sb,
343                                   ext4_fsblk_t blk)
344 {
345         struct buffer_head *bh;
346         int err;
347 
348         bh = sb_getblk(sb, blk);
349         if (unlikely(!bh))
350                 return ERR_PTR(-ENOMEM);
351         if ((err = ext4_journal_get_write_access(handle, bh))) {
352                 brelse(bh);
353                 bh = ERR_PTR(err);
354         } else {
355                 memset(bh->b_data, 0, sb->s_blocksize);
356                 set_buffer_uptodate(bh);
357         }
358 
359         return bh;
360 }
361 
362 /*
363  * If we have fewer than thresh credits, extend by EXT4_MAX_TRANS_DATA.
364  * If that fails, restart the transaction & regain write access for the
365  * buffer head which is used for block_bitmap modifications.
366  */
367 static int extend_or_restart_transaction(handle_t *handle, int thresh)
368 {
369         int err;
370 
371         if (ext4_handle_has_enough_credits(handle, thresh))
372                 return 0;
373 
374         err = ext4_journal_extend(handle, EXT4_MAX_TRANS_DATA);
375         if (err < 0)
376                 return err;
377         if (err) {
378                 err = ext4_journal_restart(handle, EXT4_MAX_TRANS_DATA);
379                 if (err)
380                         return err;
381         }
382 
383         return 0;
384 }
385 
386 /*
387  * set_flexbg_block_bitmap() mark @count blocks starting from @block used.
388  *
389  * Helper function for ext4_setup_new_group_blocks() which set .
390  *
391  * @sb: super block
392  * @handle: journal handle
393  * @flex_gd: flex group data
394  */
395 static int set_flexbg_block_bitmap(struct super_block *sb, handle_t *handle,
396                         struct ext4_new_flex_group_data *flex_gd,
397                         ext4_fsblk_t block, ext4_group_t count)
398 {
399         ext4_group_t count2;
400 
401         ext4_debug("mark blocks [%llu/%u] used\n", block, count);
402         for (count2 = count; count > 0; count -= count2, block += count2) {
403                 ext4_fsblk_t start;
404                 struct buffer_head *bh;
405                 ext4_group_t group;
406                 int err;
407 
408                 group = ext4_get_group_number(sb, block);
409                 start = ext4_group_first_block_no(sb, group);
410                 group -= flex_gd->groups[0].group;
411 
412                 count2 = EXT4_BLOCKS_PER_GROUP(sb) - (block - start);
413                 if (count2 > count)
414                         count2 = count;
415 
416                 if (flex_gd->bg_flags[group] & EXT4_BG_BLOCK_UNINIT) {
417                         BUG_ON(flex_gd->count > 1);
418                         continue;
419                 }
420 
421                 err = extend_or_restart_transaction(handle, 1);
422                 if (err)
423                         return err;
424 
425                 bh = sb_getblk(sb, flex_gd->groups[group].block_bitmap);
426                 if (unlikely(!bh))
427                         return -ENOMEM;
428 
429                 err = ext4_journal_get_write_access(handle, bh);
430                 if (err)
431                         return err;
432                 ext4_debug("mark block bitmap %#04llx (+%llu/%u)\n", block,
433                            block - start, count2);
434                 ext4_set_bits(bh->b_data, block - start, count2);
435 
436                 err = ext4_handle_dirty_metadata(handle, NULL, bh);
437                 if (unlikely(err))
438                         return err;
439                 brelse(bh);
440         }
441 
442         return 0;
443 }
444 
445 /*
446  * Set up the block and inode bitmaps, and the inode table for the new groups.
447  * This doesn't need to be part of the main transaction, since we are only
448  * changing blocks outside the actual filesystem.  We still do journaling to
449  * ensure the recovery is correct in case of a failure just after resize.
450  * If any part of this fails, we simply abort the resize.
451  *
452  * setup_new_flex_group_blocks handles a flex group as follow:
453  *  1. copy super block and GDT, and initialize group tables if necessary.
454  *     In this step, we only set bits in blocks bitmaps for blocks taken by
455  *     super block and GDT.
456  *  2. allocate group tables in block bitmaps, that is, set bits in block
457  *     bitmap for blocks taken by group tables.
458  */
459 static int setup_new_flex_group_blocks(struct super_block *sb,
460                                 struct ext4_new_flex_group_data *flex_gd)
461 {
462         int group_table_count[] = {1, 1, EXT4_SB(sb)->s_itb_per_group};
463         ext4_fsblk_t start;
464         ext4_fsblk_t block;
465         struct ext4_sb_info *sbi = EXT4_SB(sb);
466         struct ext4_super_block *es = sbi->s_es;
467         struct ext4_new_group_data *group_data = flex_gd->groups;
468         __u16 *bg_flags = flex_gd->bg_flags;
469         handle_t *handle;
470         ext4_group_t group, count;
471         struct buffer_head *bh = NULL;
472         int reserved_gdb, i, j, err = 0, err2;
473         int meta_bg;
474 
475         BUG_ON(!flex_gd->count || !group_data ||
476                group_data[0].group != sbi->s_groups_count);
477 
478         reserved_gdb = le16_to_cpu(es->s_reserved_gdt_blocks);
479         meta_bg = EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_META_BG);
480 
481         /* This transaction may be extended/restarted along the way */
482         handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, EXT4_MAX_TRANS_DATA);
483         if (IS_ERR(handle))
484                 return PTR_ERR(handle);
485 
486         group = group_data[0].group;
487         for (i = 0; i < flex_gd->count; i++, group++) {
488                 unsigned long gdblocks;
489                 ext4_grpblk_t overhead;
490 
491                 gdblocks = ext4_bg_num_gdb(sb, group);
492                 start = ext4_group_first_block_no(sb, group);
493 
494                 if (meta_bg == 0 && !ext4_bg_has_super(sb, group))
495                         goto handle_itb;
496 
497                 if (meta_bg == 1) {
498                         ext4_group_t first_group;
499                         first_group = ext4_meta_bg_first_group(sb, group);
500                         if (first_group != group + 1 &&
501                             first_group != group + EXT4_DESC_PER_BLOCK(sb) - 1)
502                                 goto handle_itb;
503                 }
504 
505                 block = start + ext4_bg_has_super(sb, group);
506                 /* Copy all of the GDT blocks into the backup in this group */
507                 for (j = 0; j < gdblocks; j++, block++) {
508                         struct buffer_head *gdb;
509 
510                         ext4_debug("update backup group %#04llx\n", block);
511                         err = extend_or_restart_transaction(handle, 1);
512                         if (err)
513                                 goto out;
514 
515                         gdb = sb_getblk(sb, block);
516                         if (unlikely(!gdb)) {
517                                 err = -ENOMEM;
518                                 goto out;
519                         }
520 
521                         err = ext4_journal_get_write_access(handle, gdb);
522                         if (err) {
523                                 brelse(gdb);
524                                 goto out;
525                         }
526                         memcpy(gdb->b_data, sbi->s_group_desc[j]->b_data,
527                                gdb->b_size);
528                         set_buffer_uptodate(gdb);
529 
530                         err = ext4_handle_dirty_metadata(handle, NULL, gdb);
531                         if (unlikely(err)) {
532                                 brelse(gdb);
533                                 goto out;
534                         }
535                         brelse(gdb);
536                 }
537 
538                 /* Zero out all of the reserved backup group descriptor
539                  * table blocks
540                  */
541                 if (ext4_bg_has_super(sb, group)) {
542                         err = sb_issue_zeroout(sb, gdblocks + start + 1,
543                                         reserved_gdb, GFP_NOFS);
544                         if (err)
545                                 goto out;
546                 }
547 
548 handle_itb:
549                 /* Initialize group tables of the grop @group */
550                 if (!(bg_flags[i] & EXT4_BG_INODE_ZEROED))
551                         goto handle_bb;
552 
553                 /* Zero out all of the inode table blocks */
554                 block = group_data[i].inode_table;
555                 ext4_debug("clear inode table blocks %#04llx -> %#04lx\n",
556                            block, sbi->s_itb_per_group);
557                 err = sb_issue_zeroout(sb, block, sbi->s_itb_per_group,
558                                        GFP_NOFS);
559                 if (err)
560                         goto out;
561 
562 handle_bb:
563                 if (bg_flags[i] & EXT4_BG_BLOCK_UNINIT)
564                         goto handle_ib;
565 
566                 /* Initialize block bitmap of the @group */
567                 block = group_data[i].block_bitmap;
568                 err = extend_or_restart_transaction(handle, 1);
569                 if (err)
570                         goto out;
571 
572                 bh = bclean(handle, sb, block);
573                 if (IS_ERR(bh)) {
574                         err = PTR_ERR(bh);
575                         goto out;
576                 }
577                 overhead = ext4_group_overhead_blocks(sb, group);
578                 if (overhead != 0) {
579                         ext4_debug("mark backup superblock %#04llx (+0)\n",
580                                    start);
581                         ext4_set_bits(bh->b_data, 0, overhead);
582                 }
583                 ext4_mark_bitmap_end(group_data[i].blocks_count,
584                                      sb->s_blocksize * 8, bh->b_data);
585                 err = ext4_handle_dirty_metadata(handle, NULL, bh);
586                 if (err)
587                         goto out;
588                 brelse(bh);
589 
590 handle_ib:
591                 if (bg_flags[i] & EXT4_BG_INODE_UNINIT)
592                         continue;
593 
594                 /* Initialize inode bitmap of the @group */
595                 block = group_data[i].inode_bitmap;
596                 err = extend_or_restart_transaction(handle, 1);
597                 if (err)
598                         goto out;
599                 /* Mark unused entries in inode bitmap used */
600                 bh = bclean(handle, sb, block);
601                 if (IS_ERR(bh)) {
602                         err = PTR_ERR(bh);
603                         goto out;
604                 }
605 
606                 ext4_mark_bitmap_end(EXT4_INODES_PER_GROUP(sb),
607                                      sb->s_blocksize * 8, bh->b_data);
608                 err = ext4_handle_dirty_metadata(handle, NULL, bh);
609                 if (err)
610                         goto out;
611                 brelse(bh);
612         }
613         bh = NULL;
614 
615         /* Mark group tables in block bitmap */
616         for (j = 0; j < GROUP_TABLE_COUNT; j++) {
617                 count = group_table_count[j];
618                 start = (&group_data[0].block_bitmap)[j];
619                 block = start;
620                 for (i = 1; i < flex_gd->count; i++) {
621                         block += group_table_count[j];
622                         if (block == (&group_data[i].block_bitmap)[j]) {
623                                 count += group_table_count[j];
624                                 continue;
625                         }
626                         err = set_flexbg_block_bitmap(sb, handle,
627                                                 flex_gd, start, count);
628                         if (err)
629                                 goto out;
630                         count = group_table_count[j];
631                         start = (&group_data[i].block_bitmap)[j];
632                         block = start;
633                 }
634 
635                 if (count) {
636                         err = set_flexbg_block_bitmap(sb, handle,
637                                                 flex_gd, start, count);
638                         if (err)
639                                 goto out;
640                 }
641         }
642 
643 out:
644         brelse(bh);
645         err2 = ext4_journal_stop(handle);
646         if (err2 && !err)
647                 err = err2;
648 
649         return err;
650 }
651 
652 /*
653  * Iterate through the groups which hold BACKUP superblock/GDT copies in an
654  * ext4 filesystem.  The counters should be initialized to 1, 5, and 7 before
655  * calling this for the first time.  In a sparse filesystem it will be the
656  * sequence of powers of 3, 5, and 7: 1, 3, 5, 7, 9, 25, 27, 49, 81, ...
657  * For a non-sparse filesystem it will be every group: 1, 2, 3, 4, ...
658  */
659 static unsigned ext4_list_backups(struct super_block *sb, unsigned *three,
660                                   unsigned *five, unsigned *seven)
661 {
662         unsigned *min = three;
663         int mult = 3;
664         unsigned ret;
665 
666         if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
667                                         EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER)) {
668                 ret = *min;
669                 *min += 1;
670                 return ret;
671         }
672 
673         if (*five < *min) {
674                 min = five;
675                 mult = 5;
676         }
677         if (*seven < *min) {
678                 min = seven;
679                 mult = 7;
680         }
681 
682         ret = *min;
683         *min *= mult;
684 
685         return ret;
686 }
687 
688 /*
689  * Check that all of the backup GDT blocks are held in the primary GDT block.
690  * It is assumed that they are stored in group order.  Returns the number of
691  * groups in current filesystem that have BACKUPS, or -ve error code.
692  */
693 static int verify_reserved_gdb(struct super_block *sb,
694                                ext4_group_t end,
695                                struct buffer_head *primary)
696 {
697         const ext4_fsblk_t blk = primary->b_blocknr;
698         unsigned three = 1;
699         unsigned five = 5;
700         unsigned seven = 7;
701         unsigned grp;
702         __le32 *p = (__le32 *)primary->b_data;
703         int gdbackups = 0;
704 
705         while ((grp = ext4_list_backups(sb, &three, &five, &seven)) < end) {
706                 if (le32_to_cpu(*p++) !=
707                     grp * EXT4_BLOCKS_PER_GROUP(sb) + blk){
708                         ext4_warning(sb, "reserved GDT %llu"
709                                      " missing grp %d (%llu)",
710                                      blk, grp,
711                                      grp *
712                                      (ext4_fsblk_t)EXT4_BLOCKS_PER_GROUP(sb) +
713                                      blk);
714                         return -EINVAL;
715                 }
716                 if (++gdbackups > EXT4_ADDR_PER_BLOCK(sb))
717                         return -EFBIG;
718         }
719 
720         return gdbackups;
721 }
722 
723 /*
724  * Called when we need to bring a reserved group descriptor table block into
725  * use from the resize inode.  The primary copy of the new GDT block currently
726  * is an indirect block (under the double indirect block in the resize inode).
727  * The new backup GDT blocks will be stored as leaf blocks in this indirect
728  * block, in group order.  Even though we know all the block numbers we need,
729  * we check to ensure that the resize inode has actually reserved these blocks.
730  *
731  * Don't need to update the block bitmaps because the blocks are still in use.
732  *
733  * We get all of the error cases out of the way, so that we are sure to not
734  * fail once we start modifying the data on disk, because JBD has no rollback.
735  */
736 static int add_new_gdb(handle_t *handle, struct inode *inode,
737                        ext4_group_t group)
738 {
739         struct super_block *sb = inode->i_sb;
740         struct ext4_super_block *es = EXT4_SB(sb)->s_es;
741         unsigned long gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
742         ext4_fsblk_t gdblock = EXT4_SB(sb)->s_sbh->b_blocknr + 1 + gdb_num;
743         struct buffer_head **o_group_desc, **n_group_desc;
744         struct buffer_head *dind;
745         struct buffer_head *gdb_bh;
746         int gdbackups;
747         struct ext4_iloc iloc;
748         __le32 *data;
749         int err;
750 
751         if (test_opt(sb, DEBUG))
752                 printk(KERN_DEBUG
753                        "EXT4-fs: ext4_add_new_gdb: adding group block %lu\n",
754                        gdb_num);
755 
756         /*
757          * If we are not using the primary superblock/GDT copy don't resize,
758          * because the user tools have no way of handling this.  Probably a
759          * bad time to do it anyways.
760          */
761         if (EXT4_SB(sb)->s_sbh->b_blocknr !=
762             le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block)) {
763                 ext4_warning(sb, "won't resize using backup superblock at %llu",
764                         (unsigned long long)EXT4_SB(sb)->s_sbh->b_blocknr);
765                 return -EPERM;
766         }
767 
768         gdb_bh = sb_bread(sb, gdblock);
769         if (!gdb_bh)
770                 return -EIO;
771 
772         gdbackups = verify_reserved_gdb(sb, group, gdb_bh);
773         if (gdbackups < 0) {
774                 err = gdbackups;
775                 goto exit_bh;
776         }
777 
778         data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK;
779         dind = sb_bread(sb, le32_to_cpu(*data));
780         if (!dind) {
781                 err = -EIO;
782                 goto exit_bh;
783         }
784 
785         data = (__le32 *)dind->b_data;
786         if (le32_to_cpu(data[gdb_num % EXT4_ADDR_PER_BLOCK(sb)]) != gdblock) {
787                 ext4_warning(sb, "new group %u GDT block %llu not reserved",
788                              group, gdblock);
789                 err = -EINVAL;
790                 goto exit_dind;
791         }
792 
793         err = ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh);
794         if (unlikely(err))
795                 goto exit_dind;
796 
797         err = ext4_journal_get_write_access(handle, gdb_bh);
798         if (unlikely(err))
799                 goto exit_dind;
800 
801         err = ext4_journal_get_write_access(handle, dind);
802         if (unlikely(err))
803                 ext4_std_error(sb, err);
804 
805         /* ext4_reserve_inode_write() gets a reference on the iloc */
806         err = ext4_reserve_inode_write(handle, inode, &iloc);
807         if (unlikely(err))
808                 goto exit_dind;
809 
810         n_group_desc = ext4_kvmalloc((gdb_num + 1) *
811                                      sizeof(struct buffer_head *),
812                                      GFP_NOFS);
813         if (!n_group_desc) {
814                 err = -ENOMEM;
815                 ext4_warning(sb, "not enough memory for %lu groups",
816                              gdb_num + 1);
817                 goto exit_inode;
818         }
819 
820         /*
821          * Finally, we have all of the possible failures behind us...
822          *
823          * Remove new GDT block from inode double-indirect block and clear out
824          * the new GDT block for use (which also "frees" the backup GDT blocks
825          * from the reserved inode).  We don't need to change the bitmaps for
826          * these blocks, because they are marked as in-use from being in the
827          * reserved inode, and will become GDT blocks (primary and backup).
828          */
829         data[gdb_num % EXT4_ADDR_PER_BLOCK(sb)] = 0;
830         err = ext4_handle_dirty_metadata(handle, NULL, dind);
831         if (unlikely(err)) {
832                 ext4_std_error(sb, err);
833                 goto exit_inode;
834         }
835         inode->i_blocks -= (gdbackups + 1) * sb->s_blocksize >> 9;
836         ext4_mark_iloc_dirty(handle, inode, &iloc);
837         memset(gdb_bh->b_data, 0, sb->s_blocksize);
838         err = ext4_handle_dirty_metadata(handle, NULL, gdb_bh);
839         if (unlikely(err)) {
840                 ext4_std_error(sb, err);
841                 goto exit_inode;
842         }
843         brelse(dind);
844 
845         o_group_desc = EXT4_SB(sb)->s_group_desc;
846         memcpy(n_group_desc, o_group_desc,
847                EXT4_SB(sb)->s_gdb_count * sizeof(struct buffer_head *));
848         n_group_desc[gdb_num] = gdb_bh;
849         EXT4_SB(sb)->s_group_desc = n_group_desc;
850         EXT4_SB(sb)->s_gdb_count++;
851         ext4_kvfree(o_group_desc);
852 
853         le16_add_cpu(&es->s_reserved_gdt_blocks, -1);
854         err = ext4_handle_dirty_super(handle, sb);
855         if (err)
856                 ext4_std_error(sb, err);
857 
858         return err;
859 
860 exit_inode:
861         ext4_kvfree(n_group_desc);
862         brelse(iloc.bh);
863 exit_dind:
864         brelse(dind);
865 exit_bh:
866         brelse(gdb_bh);
867 
868         ext4_debug("leaving with error %d\n", err);
869         return err;
870 }
871 
872 /*
873  * add_new_gdb_meta_bg is the sister of add_new_gdb.
874  */
875 static int add_new_gdb_meta_bg(struct super_block *sb,
876                                handle_t *handle, ext4_group_t group) {
877         ext4_fsblk_t gdblock;
878         struct buffer_head *gdb_bh;
879         struct buffer_head **o_group_desc, **n_group_desc;
880         unsigned long gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
881         int err;
882 
883         gdblock = ext4_meta_bg_first_block_no(sb, group) +
884                    ext4_bg_has_super(sb, group);
885         gdb_bh = sb_bread(sb, gdblock);
886         if (!gdb_bh)
887                 return -EIO;
888         n_group_desc = ext4_kvmalloc((gdb_num + 1) *
889                                      sizeof(struct buffer_head *),
890                                      GFP_NOFS);
891         if (!n_group_desc) {
892                 err = -ENOMEM;
893                 ext4_warning(sb, "not enough memory for %lu groups",
894                              gdb_num + 1);
895                 return err;
896         }
897 
898         o_group_desc = EXT4_SB(sb)->s_group_desc;
899         memcpy(n_group_desc, o_group_desc,
900                EXT4_SB(sb)->s_gdb_count * sizeof(struct buffer_head *));
901         n_group_desc[gdb_num] = gdb_bh;
902         EXT4_SB(sb)->s_group_desc = n_group_desc;
903         EXT4_SB(sb)->s_gdb_count++;
904         ext4_kvfree(o_group_desc);
905         err = ext4_journal_get_write_access(handle, gdb_bh);
906         if (unlikely(err))
907                 brelse(gdb_bh);
908         return err;
909 }
910 
911 /*
912  * Called when we are adding a new group which has a backup copy of each of
913  * the GDT blocks (i.e. sparse group) and there are reserved GDT blocks.
914  * We need to add these reserved backup GDT blocks to the resize inode, so
915  * that they are kept for future resizing and not allocated to files.
916  *
917  * Each reserved backup GDT block will go into a different indirect block.
918  * The indirect blocks are actually the primary reserved GDT blocks,
919  * so we know in advance what their block numbers are.  We only get the
920  * double-indirect block to verify it is pointing to the primary reserved
921  * GDT blocks so we don't overwrite a data block by accident.  The reserved
922  * backup GDT blocks are stored in their reserved primary GDT block.
923  */
924 static int reserve_backup_gdb(handle_t *handle, struct inode *inode,
925                               ext4_group_t group)
926 {
927         struct super_block *sb = inode->i_sb;
928         int reserved_gdb =le16_to_cpu(EXT4_SB(sb)->s_es->s_reserved_gdt_blocks);
929         struct buffer_head **primary;
930         struct buffer_head *dind;
931         struct ext4_iloc iloc;
932         ext4_fsblk_t blk;
933         __le32 *data, *end;
934         int gdbackups = 0;
935         int res, i;
936         int err;
937 
938         primary = kmalloc(reserved_gdb * sizeof(*primary), GFP_NOFS);
939         if (!primary)
940                 return -ENOMEM;
941 
942         data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK;
943         dind = sb_bread(sb, le32_to_cpu(*data));
944         if (!dind) {
945                 err = -EIO;
946                 goto exit_free;
947         }
948 
949         blk = EXT4_SB(sb)->s_sbh->b_blocknr + 1 + EXT4_SB(sb)->s_gdb_count;
950         data = (__le32 *)dind->b_data + (EXT4_SB(sb)->s_gdb_count %
951                                          EXT4_ADDR_PER_BLOCK(sb));
952         end = (__le32 *)dind->b_data + EXT4_ADDR_PER_BLOCK(sb);
953 
954         /* Get each reserved primary GDT block and verify it holds backups */
955         for (res = 0; res < reserved_gdb; res++, blk++) {
956                 if (le32_to_cpu(*data) != blk) {
957                         ext4_warning(sb, "reserved block %llu"
958                                      " not at offset %ld",
959                                      blk,
960                                      (long)(data - (__le32 *)dind->b_data));
961                         err = -EINVAL;
962                         goto exit_bh;
963                 }
964                 primary[res] = sb_bread(sb, blk);
965                 if (!primary[res]) {
966                         err = -EIO;
967                         goto exit_bh;
968                 }
969                 gdbackups = verify_reserved_gdb(sb, group, primary[res]);
970                 if (gdbackups < 0) {
971                         brelse(primary[res]);
972                         err = gdbackups;
973                         goto exit_bh;
974                 }
975                 if (++data >= end)
976                         data = (__le32 *)dind->b_data;
977         }
978 
979         for (i = 0; i < reserved_gdb; i++) {
980                 if ((err = ext4_journal_get_write_access(handle, primary[i])))
981                         goto exit_bh;
982         }
983 
984         if ((err = ext4_reserve_inode_write(handle, inode, &iloc)))
985                 goto exit_bh;
986 
987         /*
988          * Finally we can add each of the reserved backup GDT blocks from
989          * the new group to its reserved primary GDT block.
990          */
991         blk = group * EXT4_BLOCKS_PER_GROUP(sb);
992         for (i = 0; i < reserved_gdb; i++) {
993                 int err2;
994                 data = (__le32 *)primary[i]->b_data;
995                 /* printk("reserving backup %lu[%u] = %lu\n",
996                        primary[i]->b_blocknr, gdbackups,
997                        blk + primary[i]->b_blocknr); */
998                 data[gdbackups] = cpu_to_le32(blk + primary[i]->b_blocknr);
999                 err2 = ext4_handle_dirty_metadata(handle, NULL, primary[i]);
1000                 if (!err)
1001                         err = err2;
1002         }
1003         inode->i_blocks += reserved_gdb * sb->s_blocksize >> 9;
1004         ext4_mark_iloc_dirty(handle, inode, &iloc);
1005 
1006 exit_bh:
1007         while (--res >= 0)
1008                 brelse(primary[res]);
1009         brelse(dind);
1010 
1011 exit_free:
1012         kfree(primary);
1013 
1014         return err;
1015 }
1016 
1017 /*
1018  * Update the backup copies of the ext4 metadata.  These don't need to be part
1019  * of the main resize transaction, because e2fsck will re-write them if there
1020  * is a problem (basically only OOM will cause a problem).  However, we
1021  * _should_ update the backups if possible, in case the primary gets trashed
1022  * for some reason and we need to run e2fsck from a backup superblock.  The
1023  * important part is that the new block and inode counts are in the backup
1024  * superblocks, and the location of the new group metadata in the GDT backups.
1025  *
1026  * We do not need take the s_resize_lock for this, because these
1027  * blocks are not otherwise touched by the filesystem code when it is
1028  * mounted.  We don't need to worry about last changing from
1029  * sbi->s_groups_count, because the worst that can happen is that we
1030  * do not copy the full number of backups at this time.  The resize
1031  * which changed s_groups_count will backup again.
1032  */
1033 static void update_backups(struct super_block *sb, int blk_off, char *data,
1034                            int size, int meta_bg)
1035 {
1036         struct ext4_sb_info *sbi = EXT4_SB(sb);
1037         ext4_group_t last;
1038         const int bpg = EXT4_BLOCKS_PER_GROUP(sb);
1039         unsigned three = 1;
1040         unsigned five = 5;
1041         unsigned seven = 7;
1042         ext4_group_t group = 0;
1043         int rest = sb->s_blocksize - size;
1044         handle_t *handle;
1045         int err = 0, err2;
1046 
1047         handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, EXT4_MAX_TRANS_DATA);
1048         if (IS_ERR(handle)) {
1049                 group = 1;
1050                 err = PTR_ERR(handle);
1051                 goto exit_err;
1052         }
1053 
1054         if (meta_bg == 0) {
1055                 group = ext4_list_backups(sb, &three, &five, &seven);
1056                 last = sbi->s_groups_count;
1057         } else {
1058                 group = ext4_meta_bg_first_group(sb, group) + 1;
1059                 last = (ext4_group_t)(group + EXT4_DESC_PER_BLOCK(sb) - 2);
1060         }
1061 
1062         while (group < sbi->s_groups_count) {
1063                 struct buffer_head *bh;
1064                 ext4_fsblk_t backup_block;
1065 
1066                 /* Out of journal space, and can't get more - abort - so sad */
1067                 if (ext4_handle_valid(handle) &&
1068                     handle->h_buffer_credits == 0 &&
1069                     ext4_journal_extend(handle, EXT4_MAX_TRANS_DATA) &&
1070                     (err = ext4_journal_restart(handle, EXT4_MAX_TRANS_DATA)))
1071                         break;
1072 
1073                 if (meta_bg == 0)
1074                         backup_block = group * bpg + blk_off;
1075                 else
1076                         backup_block = (ext4_group_first_block_no(sb, group) +
1077                                         ext4_bg_has_super(sb, group));
1078 
1079                 bh = sb_getblk(sb, backup_block);
1080                 if (unlikely(!bh)) {
1081                         err = -ENOMEM;
1082                         break;
1083                 }
1084                 ext4_debug("update metadata backup %llu(+%llu)\n",
1085                            backup_block, backup_block -
1086                            ext4_group_first_block_no(sb, group));
1087                 if ((err = ext4_journal_get_write_access(handle, bh)))
1088                         break;
1089                 lock_buffer(bh);
1090                 memcpy(bh->b_data, data, size);
1091                 if (rest)
1092                         memset(bh->b_data + size, 0, rest);
1093                 set_buffer_uptodate(bh);
1094                 unlock_buffer(bh);
1095                 err = ext4_handle_dirty_metadata(handle, NULL, bh);
1096                 if (unlikely(err))
1097                         ext4_std_error(sb, err);
1098                 brelse(bh);
1099 
1100                 if (meta_bg == 0)
1101                         group = ext4_list_backups(sb, &three, &five, &seven);
1102                 else if (group == last)
1103                         break;
1104                 else
1105                         group = last;
1106         }
1107         if ((err2 = ext4_journal_stop(handle)) && !err)
1108                 err = err2;
1109 
1110         /*
1111          * Ugh! Need to have e2fsck write the backup copies.  It is too
1112          * late to revert the resize, we shouldn't fail just because of
1113          * the backup copies (they are only needed in case of corruption).
1114          *
1115          * However, if we got here we have a journal problem too, so we
1116          * can't really start a transaction to mark the superblock.
1117          * Chicken out and just set the flag on the hope it will be written
1118          * to disk, and if not - we will simply wait until next fsck.
1119          */
1120 exit_err:
1121         if (err) {
1122                 ext4_warning(sb, "can't update backup for group %u (err %d), "
1123                              "forcing fsck on next reboot", group, err);
1124                 sbi->s_mount_state &= ~EXT4_VALID_FS;
1125                 sbi->s_es->s_state &= cpu_to_le16(~EXT4_VALID_FS);
1126                 mark_buffer_dirty(sbi->s_sbh);
1127         }
1128 }
1129 
1130 /*
1131  * ext4_add_new_descs() adds @count group descriptor of groups
1132  * starting at @group
1133  *
1134  * @handle: journal handle
1135  * @sb: super block
1136  * @group: the group no. of the first group desc to be added
1137  * @resize_inode: the resize inode
1138  * @count: number of group descriptors to be added
1139  */
1140 static int ext4_add_new_descs(handle_t *handle, struct super_block *sb,
1141                               ext4_group_t group, struct inode *resize_inode,
1142                               ext4_group_t count)
1143 {
1144         struct ext4_sb_info *sbi = EXT4_SB(sb);
1145         struct ext4_super_block *es = sbi->s_es;
1146         struct buffer_head *gdb_bh;
1147         int i, gdb_off, gdb_num, err = 0;
1148         int meta_bg;
1149 
1150         meta_bg = EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_META_BG);
1151         for (i = 0; i < count; i++, group++) {
1152                 int reserved_gdb = ext4_bg_has_super(sb, group) ?
1153                         le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
1154 
1155                 gdb_off = group % EXT4_DESC_PER_BLOCK(sb);
1156                 gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
1157 
1158                 /*
1159                  * We will only either add reserved group blocks to a backup group
1160                  * or remove reserved blocks for the first group in a new group block.
1161                  * Doing both would be mean more complex code, and sane people don't
1162                  * use non-sparse filesystems anymore.  This is already checked above.
1163                  */
1164                 if (gdb_off) {
1165                         gdb_bh = sbi->s_group_desc[gdb_num];
1166                         err = ext4_journal_get_write_access(handle, gdb_bh);
1167 
1168                         if (!err && reserved_gdb && ext4_bg_num_gdb(sb, group))
1169                                 err = reserve_backup_gdb(handle, resize_inode, group);
1170                 } else if (meta_bg != 0) {
1171                         err = add_new_gdb_meta_bg(sb, handle, group);
1172                 } else {
1173                         err = add_new_gdb(handle, resize_inode, group);
1174                 }
1175                 if (err)
1176                         break;
1177         }
1178         return err;
1179 }
1180 
1181 static struct buffer_head *ext4_get_bitmap(struct super_block *sb, __u64 block)
1182 {
1183         struct buffer_head *bh = sb_getblk(sb, block);
1184         if (unlikely(!bh))
1185                 return NULL;
1186         if (!bh_uptodate_or_lock(bh)) {
1187                 if (bh_submit_read(bh) < 0) {
1188                         brelse(bh);
1189                         return NULL;
1190                 }
1191         }
1192 
1193         return bh;
1194 }
1195 
1196 static int ext4_set_bitmap_checksums(struct super_block *sb,
1197                                      ext4_group_t group,
1198                                      struct ext4_group_desc *gdp,
1199                                      struct ext4_new_group_data *group_data)
1200 {
1201         struct buffer_head *bh;
1202 
1203         if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
1204                                         EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
1205                 return 0;
1206 
1207         bh = ext4_get_bitmap(sb, group_data->inode_bitmap);
1208         if (!bh)
1209                 return -EIO;
1210         ext4_inode_bitmap_csum_set(sb, group, gdp, bh,
1211                                    EXT4_INODES_PER_GROUP(sb) / 8);
1212         brelse(bh);
1213 
1214         bh = ext4_get_bitmap(sb, group_data->block_bitmap);
1215         if (!bh)
1216                 return -EIO;
1217         ext4_block_bitmap_csum_set(sb, group, gdp, bh);
1218         brelse(bh);
1219 
1220         return 0;
1221 }
1222 
1223 /*
1224  * ext4_setup_new_descs() will set up the group descriptor descriptors of a flex bg
1225  */
1226 static int ext4_setup_new_descs(handle_t *handle, struct super_block *sb,
1227                                 struct ext4_new_flex_group_data *flex_gd)
1228 {
1229         struct ext4_new_group_data      *group_data = flex_gd->groups;
1230         struct ext4_group_desc          *gdp;
1231         struct ext4_sb_info             *sbi = EXT4_SB(sb);
1232         struct buffer_head              *gdb_bh;
1233         ext4_group_t                    group;
1234         __u16                           *bg_flags = flex_gd->bg_flags;
1235         int                             i, gdb_off, gdb_num, err = 0;
1236         
1237 
1238         for (i = 0; i < flex_gd->count; i++, group_data++, bg_flags++) {
1239                 group = group_data->group;
1240 
1241                 gdb_off = group % EXT4_DESC_PER_BLOCK(sb);
1242                 gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
1243 
1244                 /*
1245                  * get_write_access() has been called on gdb_bh by ext4_add_new_desc().
1246                  */
1247                 gdb_bh = sbi->s_group_desc[gdb_num];
1248                 /* Update group descriptor block for new group */
1249                 gdp = (struct ext4_group_desc *)(gdb_bh->b_data +
1250                                                  gdb_off * EXT4_DESC_SIZE(sb));
1251 
1252                 memset(gdp, 0, EXT4_DESC_SIZE(sb));
1253                 ext4_block_bitmap_set(sb, gdp, group_data->block_bitmap);
1254                 ext4_inode_bitmap_set(sb, gdp, group_data->inode_bitmap);
1255                 err = ext4_set_bitmap_checksums(sb, group, gdp, group_data);
1256                 if (err) {
1257                         ext4_std_error(sb, err);
1258                         break;
1259                 }
1260 
1261                 ext4_inode_table_set(sb, gdp, group_data->inode_table);
1262                 ext4_free_group_clusters_set(sb, gdp,
1263                         EXT4_NUM_B2C(sbi, group_data->free_blocks_count));
1264                 ext4_free_inodes_set(sb, gdp, EXT4_INODES_PER_GROUP(sb));
1265                 if (ext4_has_group_desc_csum(sb))
1266                         ext4_itable_unused_set(sb, gdp,
1267                                                EXT4_INODES_PER_GROUP(sb));
1268                 gdp->bg_flags = cpu_to_le16(*bg_flags);
1269                 ext4_group_desc_csum_set(sb, group, gdp);
1270 
1271                 err = ext4_handle_dirty_metadata(handle, NULL, gdb_bh);
1272                 if (unlikely(err)) {
1273                         ext4_std_error(sb, err);
1274                         break;
1275                 }
1276 
1277                 /*
1278                  * We can allocate memory for mb_alloc based on the new group
1279                  * descriptor
1280                  */
1281                 err = ext4_mb_add_groupinfo(sb, group, gdp);
1282                 if (err)
1283                         break;
1284         }
1285         return err;
1286 }
1287 
1288 /*
1289  * ext4_update_super() updates the super block so that the newly added
1290  * groups can be seen by the filesystem.
1291  *
1292  * @sb: super block
1293  * @flex_gd: new added groups
1294  */
1295 static void ext4_update_super(struct super_block *sb,
1296                              struct ext4_new_flex_group_data *flex_gd)
1297 {
1298         ext4_fsblk_t blocks_count = 0;
1299         ext4_fsblk_t free_blocks = 0;
1300         ext4_fsblk_t reserved_blocks = 0;
1301         struct ext4_new_group_data *group_data = flex_gd->groups;
1302         struct ext4_sb_info *sbi = EXT4_SB(sb);
1303         struct ext4_super_block *es = sbi->s_es;
1304         int i;
1305 
1306         BUG_ON(flex_gd->count == 0 || group_data == NULL);
1307         /*
1308          * Make the new blocks and inodes valid next.  We do this before
1309          * increasing the group count so that once the group is enabled,
1310          * all of its blocks and inodes are already valid.
1311          *
1312          * We always allocate group-by-group, then block-by-block or
1313          * inode-by-inode within a group, so enabling these
1314          * blocks/inodes before the group is live won't actually let us
1315          * allocate the new space yet.
1316          */
1317         for (i = 0; i < flex_gd->count; i++) {
1318                 blocks_count += group_data[i].blocks_count;
1319                 free_blocks += group_data[i].free_blocks_count;
1320         }
1321 
1322         reserved_blocks = ext4_r_blocks_count(es) * 100;
1323         reserved_blocks = div64_u64(reserved_blocks, ext4_blocks_count(es));
1324         reserved_blocks *= blocks_count;
1325         do_div(reserved_blocks, 100);
1326 
1327         ext4_blocks_count_set(es, ext4_blocks_count(es) + blocks_count);
1328         ext4_free_blocks_count_set(es, ext4_free_blocks_count(es) + free_blocks);
1329         le32_add_cpu(&es->s_inodes_count, EXT4_INODES_PER_GROUP(sb) *
1330                      flex_gd->count);
1331         le32_add_cpu(&es->s_free_inodes_count, EXT4_INODES_PER_GROUP(sb) *
1332                      flex_gd->count);
1333 
1334         ext4_debug("free blocks count %llu", ext4_free_blocks_count(es));
1335         /*
1336          * We need to protect s_groups_count against other CPUs seeing
1337          * inconsistent state in the superblock.
1338          *
1339          * The precise rules we use are:
1340          *
1341          * * Writers must perform a smp_wmb() after updating all
1342          *   dependent data and before modifying the groups count
1343          *
1344          * * Readers must perform an smp_rmb() after reading the groups
1345          *   count and before reading any dependent data.
1346          *
1347          * NB. These rules can be relaxed when checking the group count
1348          * while freeing data, as we can only allocate from a block
1349          * group after serialising against the group count, and we can
1350          * only then free after serialising in turn against that
1351          * allocation.
1352          */
1353         smp_wmb();
1354 
1355         /* Update the global fs size fields */
1356         sbi->s_groups_count += flex_gd->count;
1357         sbi->s_blockfile_groups = min_t(ext4_group_t, sbi->s_groups_count,
1358                         (EXT4_MAX_BLOCK_FILE_PHYS / EXT4_BLOCKS_PER_GROUP(sb)));
1359 
1360         /* Update the reserved block counts only once the new group is
1361          * active. */
1362         ext4_r_blocks_count_set(es, ext4_r_blocks_count(es) +
1363                                 reserved_blocks);
1364 
1365         /* Update the free space counts */
1366         percpu_counter_add(&sbi->s_freeclusters_counter,
1367                            EXT4_NUM_B2C(sbi, free_blocks));
1368         percpu_counter_add(&sbi->s_freeinodes_counter,
1369                            EXT4_INODES_PER_GROUP(sb) * flex_gd->count);
1370 
1371         ext4_debug("free blocks count %llu",
1372                    percpu_counter_read(&sbi->s_freeclusters_counter));
1373         if (EXT4_HAS_INCOMPAT_FEATURE(sb,
1374                                       EXT4_FEATURE_INCOMPAT_FLEX_BG) &&
1375             sbi->s_log_groups_per_flex) {
1376                 ext4_group_t flex_group;
1377                 flex_group = ext4_flex_group(sbi, group_data[0].group);
1378                 atomic64_add(EXT4_NUM_B2C(sbi, free_blocks),
1379                              &sbi->s_flex_groups[flex_group].free_clusters);
1380                 atomic_add(EXT4_INODES_PER_GROUP(sb) * flex_gd->count,
1381                            &sbi->s_flex_groups[flex_group].free_inodes);
1382         }
1383 
1384         /*
1385          * Update the fs overhead information
1386          */
1387         ext4_calculate_overhead(sb);
1388 
1389         if (test_opt(sb, DEBUG))
1390                 printk(KERN_DEBUG "EXT4-fs: added group %u:"
1391                        "%llu blocks(%llu free %llu reserved)\n", flex_gd->count,
1392                        blocks_count, free_blocks, reserved_blocks);
1393 }
1394 
1395 /* Add a flex group to an fs. Ensure we handle all possible error conditions
1396  * _before_ we start modifying the filesystem, because we cannot abort the
1397  * transaction and not have it write the data to disk.
1398  */
1399 static int ext4_flex_group_add(struct super_block *sb,
1400                                struct inode *resize_inode,
1401                                struct ext4_new_flex_group_data *flex_gd)
1402 {
1403         struct ext4_sb_info *sbi = EXT4_SB(sb);
1404         struct ext4_super_block *es = sbi->s_es;
1405         ext4_fsblk_t o_blocks_count;
1406         ext4_grpblk_t last;
1407         ext4_group_t group;
1408         handle_t *handle;
1409         unsigned reserved_gdb;
1410         int err = 0, err2 = 0, credit;
1411 
1412         BUG_ON(!flex_gd->count || !flex_gd->groups || !flex_gd->bg_flags);
1413 
1414         reserved_gdb = le16_to_cpu(es->s_reserved_gdt_blocks);
1415         o_blocks_count = ext4_blocks_count(es);
1416         ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
1417         BUG_ON(last);
1418 
1419         err = setup_new_flex_group_blocks(sb, flex_gd);
1420         if (err)
1421                 goto exit;
1422         /*
1423          * We will always be modifying at least the superblock and  GDT
1424          * block.  If we are adding a group past the last current GDT block,
1425          * we will also modify the inode and the dindirect block.  If we
1426          * are adding a group with superblock/GDT backups  we will also
1427          * modify each of the reserved GDT dindirect blocks.
1428          */
1429         credit = flex_gd->count * 4 + reserved_gdb;
1430         handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, credit);
1431         if (IS_ERR(handle)) {
1432                 err = PTR_ERR(handle);
1433                 goto exit;
1434         }
1435 
1436         err = ext4_journal_get_write_access(handle, sbi->s_sbh);
1437         if (err)
1438                 goto exit_journal;
1439 
1440         group = flex_gd->groups[0].group;
1441         BUG_ON(group != EXT4_SB(sb)->s_groups_count);
1442         err = ext4_add_new_descs(handle, sb, group,
1443                                 resize_inode, flex_gd->count);
1444         if (err)
1445                 goto exit_journal;
1446 
1447         err = ext4_setup_new_descs(handle, sb, flex_gd);
1448         if (err)
1449                 goto exit_journal;
1450 
1451         ext4_update_super(sb, flex_gd);
1452 
1453         err = ext4_handle_dirty_super(handle, sb);
1454 
1455 exit_journal:
1456         err2 = ext4_journal_stop(handle);
1457         if (!err)
1458                 err = err2;
1459 
1460         if (!err) {
1461                 int gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
1462                 int gdb_num_end = ((group + flex_gd->count - 1) /
1463                                    EXT4_DESC_PER_BLOCK(sb));
1464                 int meta_bg = EXT4_HAS_INCOMPAT_FEATURE(sb,
1465                                 EXT4_FEATURE_INCOMPAT_META_BG);
1466                 sector_t old_gdb = 0;
1467 
1468                 update_backups(sb, sbi->s_sbh->b_blocknr, (char *)es,
1469                                sizeof(struct ext4_super_block), 0);
1470                 for (; gdb_num <= gdb_num_end; gdb_num++) {
1471                         struct buffer_head *gdb_bh;
1472 
1473                         gdb_bh = sbi->s_group_desc[gdb_num];
1474                         if (old_gdb == gdb_bh->b_blocknr)
1475                                 continue;
1476                         update_backups(sb, gdb_bh->b_blocknr, gdb_bh->b_data,
1477                                        gdb_bh->b_size, meta_bg);
1478                         old_gdb = gdb_bh->b_blocknr;
1479                 }
1480         }
1481 exit:
1482         return err;
1483 }
1484 
1485 static int ext4_setup_next_flex_gd(struct super_block *sb,
1486                                     struct ext4_new_flex_group_data *flex_gd,
1487                                     ext4_fsblk_t n_blocks_count,
1488                                     unsigned long flexbg_size)
1489 {
1490         struct ext4_super_block *es = EXT4_SB(sb)->s_es;
1491         struct ext4_new_group_data *group_data = flex_gd->groups;
1492         ext4_fsblk_t o_blocks_count;
1493         ext4_group_t n_group;
1494         ext4_group_t group;
1495         ext4_group_t last_group;
1496         ext4_grpblk_t last;
1497         ext4_grpblk_t blocks_per_group;
1498         unsigned long i;
1499 
1500         blocks_per_group = EXT4_BLOCKS_PER_GROUP(sb);
1501 
1502         o_blocks_count = ext4_blocks_count(es);
1503 
1504         if (o_blocks_count == n_blocks_count)
1505                 return 0;
1506 
1507         ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
1508         BUG_ON(last);
1509         ext4_get_group_no_and_offset(sb, n_blocks_count - 1, &n_group, &last);
1510 
1511         last_group = group | (flexbg_size - 1);
1512         if (last_group > n_group)
1513                 last_group = n_group;
1514 
1515         flex_gd->count = last_group - group + 1;
1516 
1517         for (i = 0; i < flex_gd->count; i++) {
1518                 int overhead;
1519 
1520                 group_data[i].group = group + i;
1521                 group_data[i].blocks_count = blocks_per_group;
1522                 overhead = ext4_group_overhead_blocks(sb, group + i);
1523                 group_data[i].free_blocks_count = blocks_per_group - overhead;
1524                 if (ext4_has_group_desc_csum(sb)) {
1525                         flex_gd->bg_flags[i] = EXT4_BG_BLOCK_UNINIT |
1526                                                EXT4_BG_INODE_UNINIT;
1527                         if (!test_opt(sb, INIT_INODE_TABLE))
1528                                 flex_gd->bg_flags[i] |= EXT4_BG_INODE_ZEROED;
1529                 } else
1530                         flex_gd->bg_flags[i] = EXT4_BG_INODE_ZEROED;
1531         }
1532 
1533         if (last_group == n_group && ext4_has_group_desc_csum(sb))
1534                 /* We need to initialize block bitmap of last group. */
1535                 flex_gd->bg_flags[i - 1] &= ~EXT4_BG_BLOCK_UNINIT;
1536 
1537         if ((last_group == n_group) && (last != blocks_per_group - 1)) {
1538                 group_data[i - 1].blocks_count = last + 1;
1539                 group_data[i - 1].free_blocks_count -= blocks_per_group-
1540                                         last - 1;
1541         }
1542 
1543         return 1;
1544 }
1545 
1546 /* Add group descriptor data to an existing or new group descriptor block.
1547  * Ensure we handle all possible error conditions _before_ we start modifying
1548  * the filesystem, because we cannot abort the transaction and not have it
1549  * write the data to disk.
1550  *
1551  * If we are on a GDT block boundary, we need to get the reserved GDT block.
1552  * Otherwise, we may need to add backup GDT blocks for a sparse group.
1553  *
1554  * We only need to hold the superblock lock while we are actually adding
1555  * in the new group's counts to the superblock.  Prior to that we have
1556  * not really "added" the group at all.  We re-check that we are still
1557  * adding in the last group in case things have changed since verifying.
1558  */
1559 int ext4_group_add(struct super_block *sb, struct ext4_new_group_data *input)
1560 {
1561         struct ext4_new_flex_group_data flex_gd;
1562         struct ext4_sb_info *sbi = EXT4_SB(sb);
1563         struct ext4_super_block *es = sbi->s_es;
1564         int reserved_gdb = ext4_bg_has_super(sb, input->group) ?
1565                 le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
1566         struct inode *inode = NULL;
1567         int gdb_off;
1568         int err;
1569         __u16 bg_flags = 0;
1570 
1571         gdb_off = input->group % EXT4_DESC_PER_BLOCK(sb);
1572 
1573         if (gdb_off == 0 && !EXT4_HAS_RO_COMPAT_FEATURE(sb,
1574                                         EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER)) {
1575                 ext4_warning(sb, "Can't resize non-sparse filesystem further");
1576                 return -EPERM;
1577         }
1578 
1579         if (ext4_blocks_count(es) + input->blocks_count <
1580             ext4_blocks_count(es)) {
1581                 ext4_warning(sb, "blocks_count overflow");
1582                 return -EINVAL;
1583         }
1584 
1585         if (le32_to_cpu(es->s_inodes_count) + EXT4_INODES_PER_GROUP(sb) <
1586             le32_to_cpu(es->s_inodes_count)) {
1587                 ext4_warning(sb, "inodes_count overflow");
1588                 return -EINVAL;
1589         }
1590 
1591         if (reserved_gdb || gdb_off == 0) {
1592                 if (!EXT4_HAS_COMPAT_FEATURE(sb,
1593                                              EXT4_FEATURE_COMPAT_RESIZE_INODE)
1594                     || !le16_to_cpu(es->s_reserved_gdt_blocks)) {
1595                         ext4_warning(sb,
1596                                      "No reserved GDT blocks, can't resize");
1597                         return -EPERM;
1598                 }
1599                 inode = ext4_iget(sb, EXT4_RESIZE_INO);
1600                 if (IS_ERR(inode)) {
1601                         ext4_warning(sb, "Error opening resize inode");
1602                         return PTR_ERR(inode);
1603                 }
1604         }
1605 
1606 
1607         err = verify_group_input(sb, input);
1608         if (err)
1609                 goto out;
1610 
1611         err = ext4_alloc_flex_bg_array(sb, input->group + 1);
1612         if (err)
1613                 goto out;
1614 
1615         err = ext4_mb_alloc_groupinfo(sb, input->group + 1);
1616         if (err)
1617                 goto out;
1618 
1619         flex_gd.count = 1;
1620         flex_gd.groups = input;
1621         flex_gd.bg_flags = &bg_flags;
1622         err = ext4_flex_group_add(sb, inode, &flex_gd);
1623 out:
1624         iput(inode);
1625         return err;
1626 } /* ext4_group_add */
1627 
1628 /*
1629  * extend a group without checking assuming that checking has been done.
1630  */
1631 static int ext4_group_extend_no_check(struct super_block *sb,
1632                                       ext4_fsblk_t o_blocks_count, ext4_grpblk_t add)
1633 {
1634         struct ext4_super_block *es = EXT4_SB(sb)->s_es;
1635         handle_t *handle;
1636         int err = 0, err2;
1637 
1638         /* We will update the superblock, one block bitmap, and
1639          * one group descriptor via ext4_group_add_blocks().
1640          */
1641         handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, 3);
1642         if (IS_ERR(handle)) {
1643                 err = PTR_ERR(handle);
1644                 ext4_warning(sb, "error %d on journal start", err);
1645                 return err;
1646         }
1647 
1648         err = ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh);
1649         if (err) {
1650                 ext4_warning(sb, "error %d on journal write access", err);
1651                 goto errout;
1652         }
1653 
1654         ext4_blocks_count_set(es, o_blocks_count + add);
1655         ext4_free_blocks_count_set(es, ext4_free_blocks_count(es) + add);
1656         ext4_debug("freeing blocks %llu through %llu\n", o_blocks_count,
1657                    o_blocks_count + add);
1658         /* We add the blocks to the bitmap and set the group need init bit */
1659         err = ext4_group_add_blocks(handle, sb, o_blocks_count, add);
1660         if (err)
1661                 goto errout;
1662         ext4_handle_dirty_super(handle, sb);
1663         ext4_debug("freed blocks %llu through %llu\n", o_blocks_count,
1664                    o_blocks_count + add);
1665 errout:
1666         err2 = ext4_journal_stop(handle);
1667         if (err2 && !err)
1668                 err = err2;
1669 
1670         if (!err) {
1671                 if (test_opt(sb, DEBUG))
1672                         printk(KERN_DEBUG "EXT4-fs: extended group to %llu "
1673                                "blocks\n", ext4_blocks_count(es));
1674                 update_backups(sb, EXT4_SB(sb)->s_sbh->b_blocknr,
1675                                (char *)es, sizeof(struct ext4_super_block), 0);
1676         }
1677         return err;
1678 }
1679 
1680 /*
1681  * Extend the filesystem to the new number of blocks specified.  This entry
1682  * point is only used to extend the current filesystem to the end of the last
1683  * existing group.  It can be accessed via ioctl, or by "remount,resize=<size>"
1684  * for emergencies (because it has no dependencies on reserved blocks).
1685  *
1686  * If we _really_ wanted, we could use default values to call ext4_group_add()
1687  * allow the "remount" trick to work for arbitrary resizing, assuming enough
1688  * GDT blocks are reserved to grow to the desired size.
1689  */
1690 int ext4_group_extend(struct super_block *sb, struct ext4_super_block *es,
1691                       ext4_fsblk_t n_blocks_count)
1692 {
1693         ext4_fsblk_t o_blocks_count;
1694         ext4_grpblk_t last;
1695         ext4_grpblk_t add;
1696         struct buffer_head *bh;
1697         int err;
1698         ext4_group_t group;
1699 
1700         o_blocks_count = ext4_blocks_count(es);
1701 
1702         if (test_opt(sb, DEBUG))
1703                 ext4_msg(sb, KERN_DEBUG,
1704                          "extending last group from %llu to %llu blocks",
1705                          o_blocks_count, n_blocks_count);
1706 
1707         if (n_blocks_count == 0 || n_blocks_count == o_blocks_count)
1708                 return 0;
1709 
1710         if (n_blocks_count > (sector_t)(~0ULL) >> (sb->s_blocksize_bits - 9)) {
1711                 ext4_msg(sb, KERN_ERR,
1712                          "filesystem too large to resize to %llu blocks safely",
1713                          n_blocks_count);
1714                 if (sizeof(sector_t) < 8)
1715                         ext4_warning(sb, "CONFIG_LBDAF not enabled");
1716                 return -EINVAL;
1717         }
1718 
1719         if (n_blocks_count < o_blocks_count) {
1720                 ext4_warning(sb, "can't shrink FS - resize aborted");
1721                 return -EINVAL;
1722         }
1723 
1724         /* Handle the remaining blocks in the last group only. */
1725         ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
1726 
1727         if (last == 0) {
1728                 ext4_warning(sb, "need to use ext2online to resize further");
1729                 return -EPERM;
1730         }
1731 
1732         add = EXT4_BLOCKS_PER_GROUP(sb) - last;
1733 
1734         if (o_blocks_count + add < o_blocks_count) {
1735                 ext4_warning(sb, "blocks_count overflow");
1736                 return -EINVAL;
1737         }
1738 
1739         if (o_blocks_count + add > n_blocks_count)
1740                 add = n_blocks_count - o_blocks_count;
1741 
1742         if (o_blocks_count + add < n_blocks_count)
1743                 ext4_warning(sb, "will only finish group (%llu blocks, %u new)",
1744                              o_blocks_count + add, add);
1745 
1746         /* See if the device is actually as big as what was requested */
1747         bh = sb_bread(sb, o_blocks_count + add - 1);
1748         if (!bh) {
1749                 ext4_warning(sb, "can't read last block, resize aborted");
1750                 return -ENOSPC;
1751         }
1752         brelse(bh);
1753 
1754         err = ext4_group_extend_no_check(sb, o_blocks_count, add);
1755         return err;
1756 } /* ext4_group_extend */
1757 
1758 
1759 static int num_desc_blocks(struct super_block *sb, ext4_group_t groups)
1760 {
1761         return (groups + EXT4_DESC_PER_BLOCK(sb) - 1) / EXT4_DESC_PER_BLOCK(sb);
1762 }
1763 
1764 /*
1765  * Release the resize inode and drop the resize_inode feature if there
1766  * are no more reserved gdt blocks, and then convert the file system
1767  * to enable meta_bg
1768  */
1769 static int ext4_convert_meta_bg(struct super_block *sb, struct inode *inode)
1770 {
1771         handle_t *handle;
1772         struct ext4_sb_info *sbi = EXT4_SB(sb);
1773         struct ext4_super_block *es = sbi->s_es;
1774         struct ext4_inode_info *ei = EXT4_I(inode);
1775         ext4_fsblk_t nr;
1776         int i, ret, err = 0;
1777         int credits = 1;
1778 
1779         ext4_msg(sb, KERN_INFO, "Converting file system to meta_bg");
1780         if (inode) {
1781                 if (es->s_reserved_gdt_blocks) {
1782                         ext4_error(sb, "Unexpected non-zero "
1783                                    "s_reserved_gdt_blocks");
1784                         return -EPERM;
1785                 }
1786 
1787                 /* Do a quick sanity check of the resize inode */
1788                 if (inode->i_blocks != 1 << (inode->i_blkbits - 9))
1789                         goto invalid_resize_inode;
1790                 for (i = 0; i < EXT4_N_BLOCKS; i++) {
1791                         if (i == EXT4_DIND_BLOCK) {
1792                                 if (ei->i_data[i])
1793                                         continue;
1794                                 else
1795                                         goto invalid_resize_inode;
1796                         }
1797                         if (ei->i_data[i])
1798                                 goto invalid_resize_inode;
1799                 }
1800                 credits += 3;   /* block bitmap, bg descriptor, resize inode */
1801         }
1802 
1803         handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, credits);
1804         if (IS_ERR(handle))
1805                 return PTR_ERR(handle);
1806 
1807         err = ext4_journal_get_write_access(handle, sbi->s_sbh);
1808         if (err)
1809                 goto errout;
1810 
1811         EXT4_CLEAR_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_RESIZE_INODE);
1812         EXT4_SET_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_META_BG);
1813         sbi->s_es->s_first_meta_bg =
1814                 cpu_to_le32(num_desc_blocks(sb, sbi->s_groups_count));
1815 
1816         err = ext4_handle_dirty_super(handle, sb);
1817         if (err) {
1818                 ext4_std_error(sb, err);
1819                 goto errout;
1820         }
1821 
1822         if (inode) {
1823                 nr = le32_to_cpu(ei->i_data[EXT4_DIND_BLOCK]);
1824                 ext4_free_blocks(handle, inode, NULL, nr, 1,
1825                                  EXT4_FREE_BLOCKS_METADATA |
1826                                  EXT4_FREE_BLOCKS_FORGET);
1827                 ei->i_data[EXT4_DIND_BLOCK] = 0;
1828                 inode->i_blocks = 0;
1829 
1830                 err = ext4_mark_inode_dirty(handle, inode);
1831                 if (err)
1832                         ext4_std_error(sb, err);
1833         }
1834 
1835 errout:
1836         ret = ext4_journal_stop(handle);
1837         if (!err)
1838                 err = ret;
1839         return ret;
1840 
1841 invalid_resize_inode:
1842         ext4_error(sb, "corrupted/inconsistent resize inode");
1843         return -EINVAL;
1844 }
1845 
1846 /*
1847  * ext4_resize_fs() resizes a fs to new size specified by @n_blocks_count
1848  *
1849  * @sb: super block of the fs to be resized
1850  * @n_blocks_count: the number of blocks resides in the resized fs
1851  */
1852 int ext4_resize_fs(struct super_block *sb, ext4_fsblk_t n_blocks_count)
1853 {
1854         struct ext4_new_flex_group_data *flex_gd = NULL;
1855         struct ext4_sb_info *sbi = EXT4_SB(sb);
1856         struct ext4_super_block *es = sbi->s_es;
1857         struct buffer_head *bh;
1858         struct inode *resize_inode = NULL;
1859         ext4_grpblk_t add, offset;
1860         unsigned long n_desc_blocks;
1861         unsigned long o_desc_blocks;
1862         ext4_group_t o_group;
1863         ext4_group_t n_group;
1864         ext4_fsblk_t o_blocks_count;
1865         ext4_fsblk_t n_blocks_count_retry = 0;
1866         unsigned long last_update_time = 0;
1867         int err = 0, flexbg_size = 1 << sbi->s_log_groups_per_flex;
1868         int meta_bg;
1869 
1870         /* See if the device is actually as big as what was requested */
1871         bh = sb_bread(sb, n_blocks_count - 1);
1872         if (!bh) {
1873                 ext4_warning(sb, "can't read last block, resize aborted");
1874                 return -ENOSPC;
1875         }
1876         brelse(bh);
1877 
1878 retry:
1879         o_blocks_count = ext4_blocks_count(es);
1880 
1881         ext4_msg(sb, KERN_INFO, "resizing filesystem from %llu "
1882                  "to %llu blocks", o_blocks_count, n_blocks_count);
1883 
1884         if (n_blocks_count < o_blocks_count) {
1885                 /* On-line shrinking not supported */
1886                 ext4_warning(sb, "can't shrink FS - resize aborted");
1887                 return -EINVAL;
1888         }
1889 
1890         if (n_blocks_count == o_blocks_count)
1891                 /* Nothing need to do */
1892                 return 0;
1893 
1894         n_group = ext4_get_group_number(sb, n_blocks_count - 1);
1895         if (n_group > (0xFFFFFFFFUL / EXT4_INODES_PER_GROUP(sb))) {
1896                 ext4_warning(sb, "resize would cause inodes_count overflow");
1897                 return -EINVAL;
1898         }
1899         ext4_get_group_no_and_offset(sb, o_blocks_count - 1, &o_group, &offset);
1900 
1901         n_desc_blocks = num_desc_blocks(sb, n_group + 1);
1902         o_desc_blocks = num_desc_blocks(sb, sbi->s_groups_count);
1903 
1904         meta_bg = EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_META_BG);
1905 
1906         if (EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_RESIZE_INODE)) {
1907                 if (meta_bg) {
1908                         ext4_error(sb, "resize_inode and meta_bg enabled "
1909                                    "simultaneously");
1910                         return -EINVAL;
1911                 }
1912                 if (n_desc_blocks > o_desc_blocks +
1913                     le16_to_cpu(es->s_reserved_gdt_blocks)) {
1914                         n_blocks_count_retry = n_blocks_count;
1915                         n_desc_blocks = o_desc_blocks +
1916                                 le16_to_cpu(es->s_reserved_gdt_blocks);
1917                         n_group = n_desc_blocks * EXT4_DESC_PER_BLOCK(sb);
1918                         n_blocks_count = n_group * EXT4_BLOCKS_PER_GROUP(sb);
1919                         n_group--; /* set to last group number */
1920                 }
1921 
1922                 if (!resize_inode)
1923                         resize_inode = ext4_iget(sb, EXT4_RESIZE_INO);
1924                 if (IS_ERR(resize_inode)) {
1925                         ext4_warning(sb, "Error opening resize inode");
1926                         return PTR_ERR(resize_inode);
1927                 }
1928         }
1929 
1930         if ((!resize_inode && !meta_bg) || n_blocks_count == o_blocks_count) {
1931                 err = ext4_convert_meta_bg(sb, resize_inode);
1932                 if (err)
1933                         goto out;
1934                 if (resize_inode) {
1935                         iput(resize_inode);
1936                         resize_inode = NULL;
1937                 }
1938                 if (n_blocks_count_retry) {
1939                         n_blocks_count = n_blocks_count_retry;
1940                         n_blocks_count_retry = 0;
1941                         goto retry;
1942                 }
1943         }
1944 
1945         /* extend the last group */
1946         if (n_group == o_group)
1947                 add = n_blocks_count - o_blocks_count;
1948         else
1949                 add = EXT4_BLOCKS_PER_GROUP(sb) - (offset + 1);
1950         if (add > 0) {
1951                 err = ext4_group_extend_no_check(sb, o_blocks_count, add);
1952                 if (err)
1953                         goto out;
1954         }
1955 
1956         if (ext4_blocks_count(es) == n_blocks_count)
1957                 goto out;
1958 
1959         err = ext4_alloc_flex_bg_array(sb, n_group + 1);
1960         if (err)
1961                 return err;
1962 
1963         err = ext4_mb_alloc_groupinfo(sb, n_group + 1);
1964         if (err)
1965                 goto out;
1966 
1967         flex_gd = alloc_flex_gd(flexbg_size);
1968         if (flex_gd == NULL) {
1969                 err = -ENOMEM;
1970                 goto out;
1971         }
1972 
1973         /* Add flex groups. Note that a regular group is a
1974          * flex group with 1 group.
1975          */
1976         while (ext4_setup_next_flex_gd(sb, flex_gd, n_blocks_count,
1977                                               flexbg_size)) {
1978                 if (jiffies - last_update_time > HZ * 10) {
1979                         if (last_update_time)
1980                                 ext4_msg(sb, KERN_INFO,
1981                                          "resized to %llu blocks",
1982                                          ext4_blocks_count(es));
1983                         last_update_time = jiffies;
1984                 }
1985                 if (ext4_alloc_group_tables(sb, flex_gd, flexbg_size) != 0)
1986                         break;
1987                 err = ext4_flex_group_add(sb, resize_inode, flex_gd);
1988                 if (unlikely(err))
1989                         break;
1990         }
1991 
1992         if (!err && n_blocks_count_retry) {
1993                 n_blocks_count = n_blocks_count_retry;
1994                 n_blocks_count_retry = 0;
1995                 free_flex_gd(flex_gd);
1996                 flex_gd = NULL;
1997                 goto retry;
1998         }
1999 
2000 out:
2001         if (flex_gd)
2002                 free_flex_gd(flex_gd);
2003         if (resize_inode != NULL)
2004                 iput(resize_inode);
2005         ext4_msg(sb, KERN_INFO, "resized filesystem to %llu", n_blocks_count);
2006         return err;
2007 }
2008 

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