ext4: fix BUG when calling ext4_error with locked block group
[linux-2.6] / fs / ext4 / balloc.c
1 /*
2  *  linux/fs/ext4/balloc.c
3  *
4  * Copyright (C) 1992, 1993, 1994, 1995
5  * Remy Card (card@masi.ibp.fr)
6  * Laboratoire MASI - Institut Blaise Pascal
7  * Universite Pierre et Marie Curie (Paris VI)
8  *
9  *  Enhanced block allocation by Stephen Tweedie (sct@redhat.com), 1993
10  *  Big-endian to little-endian byte-swapping/bitmaps by
11  *        David S. Miller (davem@caip.rutgers.edu), 1995
12  */
13
14 #include <linux/time.h>
15 #include <linux/capability.h>
16 #include <linux/fs.h>
17 #include <linux/jbd2.h>
18 #include <linux/quotaops.h>
19 #include <linux/buffer_head.h>
20 #include "ext4.h"
21 #include "ext4_jbd2.h"
22 #include "group.h"
23 #include "mballoc.h"
24
25 /*
26  * balloc.c contains the blocks allocation and deallocation routines
27  */
28
29 /*
30  * Calculate the block group number and offset, given a block number
31  */
32 void ext4_get_group_no_and_offset(struct super_block *sb, ext4_fsblk_t blocknr,
33                 ext4_group_t *blockgrpp, ext4_grpblk_t *offsetp)
34 {
35         struct ext4_super_block *es = EXT4_SB(sb)->s_es;
36         ext4_grpblk_t offset;
37
38         blocknr = blocknr - le32_to_cpu(es->s_first_data_block);
39         offset = do_div(blocknr, EXT4_BLOCKS_PER_GROUP(sb));
40         if (offsetp)
41                 *offsetp = offset;
42         if (blockgrpp)
43                 *blockgrpp = blocknr;
44
45 }
46
47 static int ext4_block_in_group(struct super_block *sb, ext4_fsblk_t block,
48                         ext4_group_t block_group)
49 {
50         ext4_group_t actual_group;
51         ext4_get_group_no_and_offset(sb, block, &actual_group, NULL);
52         if (actual_group == block_group)
53                 return 1;
54         return 0;
55 }
56
57 static int ext4_group_used_meta_blocks(struct super_block *sb,
58                                 ext4_group_t block_group)
59 {
60         ext4_fsblk_t tmp;
61         struct ext4_sb_info *sbi = EXT4_SB(sb);
62         /* block bitmap, inode bitmap, and inode table blocks */
63         int used_blocks = sbi->s_itb_per_group + 2;
64
65         if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG)) {
66                 struct ext4_group_desc *gdp;
67                 struct buffer_head *bh;
68
69                 gdp = ext4_get_group_desc(sb, block_group, &bh);
70                 if (!ext4_block_in_group(sb, ext4_block_bitmap(sb, gdp),
71                                         block_group))
72                         used_blocks--;
73
74                 if (!ext4_block_in_group(sb, ext4_inode_bitmap(sb, gdp),
75                                         block_group))
76                         used_blocks--;
77
78                 tmp = ext4_inode_table(sb, gdp);
79                 for (; tmp < ext4_inode_table(sb, gdp) +
80                                 sbi->s_itb_per_group; tmp++) {
81                         if (!ext4_block_in_group(sb, tmp, block_group))
82                                 used_blocks -= 1;
83                 }
84         }
85         return used_blocks;
86 }
87
88 /* Initializes an uninitialized block bitmap if given, and returns the
89  * number of blocks free in the group. */
90 unsigned ext4_init_block_bitmap(struct super_block *sb, struct buffer_head *bh,
91                  ext4_group_t block_group, struct ext4_group_desc *gdp)
92 {
93         int bit, bit_max;
94         unsigned free_blocks, group_blocks;
95         struct ext4_sb_info *sbi = EXT4_SB(sb);
96
97         if (bh) {
98                 J_ASSERT_BH(bh, buffer_locked(bh));
99
100                 /* If checksum is bad mark all blocks used to prevent allocation
101                  * essentially implementing a per-group read-only flag. */
102                 if (!ext4_group_desc_csum_verify(sbi, block_group, gdp)) {
103                         ext4_error(sb, __func__,
104                                   "Checksum bad for group %u", block_group);
105                         gdp->bg_free_blocks_count = 0;
106                         gdp->bg_free_inodes_count = 0;
107                         gdp->bg_itable_unused = 0;
108                         memset(bh->b_data, 0xff, sb->s_blocksize);
109                         return 0;
110                 }
111                 memset(bh->b_data, 0, sb->s_blocksize);
112         }
113
114         /* Check for superblock and gdt backups in this group */
115         bit_max = ext4_bg_has_super(sb, block_group);
116
117         if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_META_BG) ||
118             block_group < le32_to_cpu(sbi->s_es->s_first_meta_bg) *
119                           sbi->s_desc_per_block) {
120                 if (bit_max) {
121                         bit_max += ext4_bg_num_gdb(sb, block_group);
122                         bit_max +=
123                                 le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks);
124                 }
125         } else { /* For META_BG_BLOCK_GROUPS */
126                 bit_max += ext4_bg_num_gdb(sb, block_group);
127         }
128
129         if (block_group == sbi->s_groups_count - 1) {
130                 /*
131                  * Even though mke2fs always initialize first and last group
132                  * if some other tool enabled the EXT4_BG_BLOCK_UNINIT we need
133                  * to make sure we calculate the right free blocks
134                  */
135                 group_blocks = ext4_blocks_count(sbi->s_es) -
136                         le32_to_cpu(sbi->s_es->s_first_data_block) -
137                         (EXT4_BLOCKS_PER_GROUP(sb) * (sbi->s_groups_count - 1));
138         } else {
139                 group_blocks = EXT4_BLOCKS_PER_GROUP(sb);
140         }
141
142         free_blocks = group_blocks - bit_max;
143
144         if (bh) {
145                 ext4_fsblk_t start, tmp;
146                 int flex_bg = 0;
147
148                 for (bit = 0; bit < bit_max; bit++)
149                         ext4_set_bit(bit, bh->b_data);
150
151                 start = ext4_group_first_block_no(sb, block_group);
152
153                 if (EXT4_HAS_INCOMPAT_FEATURE(sb,
154                                               EXT4_FEATURE_INCOMPAT_FLEX_BG))
155                         flex_bg = 1;
156
157                 /* Set bits for block and inode bitmaps, and inode table */
158                 tmp = ext4_block_bitmap(sb, gdp);
159                 if (!flex_bg || ext4_block_in_group(sb, tmp, block_group))
160                         ext4_set_bit(tmp - start, bh->b_data);
161
162                 tmp = ext4_inode_bitmap(sb, gdp);
163                 if (!flex_bg || ext4_block_in_group(sb, tmp, block_group))
164                         ext4_set_bit(tmp - start, bh->b_data);
165
166                 tmp = ext4_inode_table(sb, gdp);
167                 for (; tmp < ext4_inode_table(sb, gdp) +
168                                 sbi->s_itb_per_group; tmp++) {
169                         if (!flex_bg ||
170                                 ext4_block_in_group(sb, tmp, block_group))
171                                 ext4_set_bit(tmp - start, bh->b_data);
172                 }
173                 /*
174                  * Also if the number of blocks within the group is
175                  * less than the blocksize * 8 ( which is the size
176                  * of bitmap ), set rest of the block bitmap to 1
177                  */
178                 mark_bitmap_end(group_blocks, sb->s_blocksize * 8, bh->b_data);
179         }
180         return free_blocks - ext4_group_used_meta_blocks(sb, block_group);
181 }
182
183
184 /*
185  * The free blocks are managed by bitmaps.  A file system contains several
186  * blocks groups.  Each group contains 1 bitmap block for blocks, 1 bitmap
187  * block for inodes, N blocks for the inode table and data blocks.
188  *
189  * The file system contains group descriptors which are located after the
190  * super block.  Each descriptor contains the number of the bitmap block and
191  * the free blocks count in the block.  The descriptors are loaded in memory
192  * when a file system is mounted (see ext4_fill_super).
193  */
194
195
196 #define in_range(b, first, len) ((b) >= (first) && (b) <= (first) + (len) - 1)
197
198 /**
199  * ext4_get_group_desc() -- load group descriptor from disk
200  * @sb:                 super block
201  * @block_group:        given block group
202  * @bh:                 pointer to the buffer head to store the block
203  *                      group descriptor
204  */
205 struct ext4_group_desc * ext4_get_group_desc(struct super_block *sb,
206                                              ext4_group_t block_group,
207                                              struct buffer_head **bh)
208 {
209         unsigned int group_desc;
210         unsigned int offset;
211         struct ext4_group_desc *desc;
212         struct ext4_sb_info *sbi = EXT4_SB(sb);
213
214         if (block_group >= sbi->s_groups_count) {
215                 ext4_error(sb, "ext4_get_group_desc",
216                            "block_group >= groups_count - "
217                            "block_group = %u, groups_count = %u",
218                            block_group, sbi->s_groups_count);
219
220                 return NULL;
221         }
222         smp_rmb();
223
224         group_desc = block_group >> EXT4_DESC_PER_BLOCK_BITS(sb);
225         offset = block_group & (EXT4_DESC_PER_BLOCK(sb) - 1);
226         if (!sbi->s_group_desc[group_desc]) {
227                 ext4_error(sb, "ext4_get_group_desc",
228                            "Group descriptor not loaded - "
229                            "block_group = %u, group_desc = %u, desc = %u",
230                            block_group, group_desc, offset);
231                 return NULL;
232         }
233
234         desc = (struct ext4_group_desc *)(
235                 (__u8 *)sbi->s_group_desc[group_desc]->b_data +
236                 offset * EXT4_DESC_SIZE(sb));
237         if (bh)
238                 *bh = sbi->s_group_desc[group_desc];
239         return desc;
240 }
241
242 static int ext4_valid_block_bitmap(struct super_block *sb,
243                                         struct ext4_group_desc *desc,
244                                         unsigned int block_group,
245                                         struct buffer_head *bh)
246 {
247         ext4_grpblk_t offset;
248         ext4_grpblk_t next_zero_bit;
249         ext4_fsblk_t bitmap_blk;
250         ext4_fsblk_t group_first_block;
251
252         if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG)) {
253                 /* with FLEX_BG, the inode/block bitmaps and itable
254                  * blocks may not be in the group at all
255                  * so the bitmap validation will be skipped for those groups
256                  * or it has to also read the block group where the bitmaps
257                  * are located to verify they are set.
258                  */
259                 return 1;
260         }
261         group_first_block = ext4_group_first_block_no(sb, block_group);
262
263         /* check whether block bitmap block number is set */
264         bitmap_blk = ext4_block_bitmap(sb, desc);
265         offset = bitmap_blk - group_first_block;
266         if (!ext4_test_bit(offset, bh->b_data))
267                 /* bad block bitmap */
268                 goto err_out;
269
270         /* check whether the inode bitmap block number is set */
271         bitmap_blk = ext4_inode_bitmap(sb, desc);
272         offset = bitmap_blk - group_first_block;
273         if (!ext4_test_bit(offset, bh->b_data))
274                 /* bad block bitmap */
275                 goto err_out;
276
277         /* check whether the inode table block number is set */
278         bitmap_blk = ext4_inode_table(sb, desc);
279         offset = bitmap_blk - group_first_block;
280         next_zero_bit = ext4_find_next_zero_bit(bh->b_data,
281                                 offset + EXT4_SB(sb)->s_itb_per_group,
282                                 offset);
283         if (next_zero_bit >= offset + EXT4_SB(sb)->s_itb_per_group)
284                 /* good bitmap for inode tables */
285                 return 1;
286
287 err_out:
288         ext4_error(sb, __func__,
289                         "Invalid block bitmap - "
290                         "block_group = %d, block = %llu",
291                         block_group, bitmap_blk);
292         return 0;
293 }
294 /**
295  * ext4_read_block_bitmap()
296  * @sb:                 super block
297  * @block_group:        given block group
298  *
299  * Read the bitmap for a given block_group,and validate the
300  * bits for block/inode/inode tables are set in the bitmaps
301  *
302  * Return buffer_head on success or NULL in case of failure.
303  */
304 struct buffer_head *
305 ext4_read_block_bitmap(struct super_block *sb, ext4_group_t block_group)
306 {
307         struct ext4_group_desc *desc;
308         struct buffer_head *bh = NULL;
309         ext4_fsblk_t bitmap_blk;
310
311         desc = ext4_get_group_desc(sb, block_group, NULL);
312         if (!desc)
313                 return NULL;
314         bitmap_blk = ext4_block_bitmap(sb, desc);
315         bh = sb_getblk(sb, bitmap_blk);
316         if (unlikely(!bh)) {
317                 ext4_error(sb, __func__,
318                             "Cannot read block bitmap - "
319                             "block_group = %u, block_bitmap = %llu",
320                             block_group, bitmap_blk);
321                 return NULL;
322         }
323         if (buffer_uptodate(bh) &&
324             !(desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)))
325                 return bh;
326
327         lock_buffer(bh);
328         spin_lock(sb_bgl_lock(EXT4_SB(sb), block_group));
329         if (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
330                 ext4_init_block_bitmap(sb, bh, block_group, desc);
331                 set_buffer_uptodate(bh);
332                 unlock_buffer(bh);
333                 spin_unlock(sb_bgl_lock(EXT4_SB(sb), block_group));
334                 return bh;
335         }
336         spin_unlock(sb_bgl_lock(EXT4_SB(sb), block_group));
337         if (bh_submit_read(bh) < 0) {
338                 put_bh(bh);
339                 ext4_error(sb, __func__,
340                             "Cannot read block bitmap - "
341                             "block_group = %u, block_bitmap = %llu",
342                             block_group, bitmap_blk);
343                 return NULL;
344         }
345         ext4_valid_block_bitmap(sb, desc, block_group, bh);
346         /*
347          * file system mounted not to panic on error,
348          * continue with corrupt bitmap
349          */
350         return bh;
351 }
352
353 /**
354  * ext4_add_groupblocks() -- Add given blocks to an existing group
355  * @handle:                     handle to this transaction
356  * @sb:                         super block
357  * @block:                      start physcial block to add to the block group
358  * @count:                      number of blocks to free
359  *
360  * This marks the blocks as free in the bitmap. We ask the
361  * mballoc to reload the buddy after this by setting group
362  * EXT4_GROUP_INFO_NEED_INIT_BIT flag
363  */
364 void ext4_add_groupblocks(handle_t *handle, struct super_block *sb,
365                          ext4_fsblk_t block, unsigned long count)
366 {
367         struct buffer_head *bitmap_bh = NULL;
368         struct buffer_head *gd_bh;
369         ext4_group_t block_group;
370         ext4_grpblk_t bit;
371         unsigned int i;
372         struct ext4_group_desc *desc;
373         struct ext4_super_block *es;
374         struct ext4_sb_info *sbi;
375         int err = 0, ret;
376         ext4_grpblk_t blocks_freed;
377         struct ext4_group_info *grp;
378
379         sbi = EXT4_SB(sb);
380         es = sbi->s_es;
381         ext4_debug("Adding block(s) %llu-%llu\n", block, block + count - 1);
382
383         ext4_get_group_no_and_offset(sb, block, &block_group, &bit);
384         grp = ext4_get_group_info(sb, block_group);
385         /*
386          * Check to see if we are freeing blocks across a group
387          * boundary.
388          */
389         if (bit + count > EXT4_BLOCKS_PER_GROUP(sb)) {
390                 goto error_return;
391         }
392         bitmap_bh = ext4_read_block_bitmap(sb, block_group);
393         if (!bitmap_bh)
394                 goto error_return;
395         desc = ext4_get_group_desc(sb, block_group, &gd_bh);
396         if (!desc)
397                 goto error_return;
398
399         if (in_range(ext4_block_bitmap(sb, desc), block, count) ||
400             in_range(ext4_inode_bitmap(sb, desc), block, count) ||
401             in_range(block, ext4_inode_table(sb, desc), sbi->s_itb_per_group) ||
402             in_range(block + count - 1, ext4_inode_table(sb, desc),
403                      sbi->s_itb_per_group)) {
404                 ext4_error(sb, __func__,
405                            "Adding blocks in system zones - "
406                            "Block = %llu, count = %lu",
407                            block, count);
408                 goto error_return;
409         }
410
411         /*
412          * We are about to add blocks to the bitmap,
413          * so we need undo access.
414          */
415         BUFFER_TRACE(bitmap_bh, "getting undo access");
416         err = ext4_journal_get_undo_access(handle, bitmap_bh);
417         if (err)
418                 goto error_return;
419
420         /*
421          * We are about to modify some metadata.  Call the journal APIs
422          * to unshare ->b_data if a currently-committing transaction is
423          * using it
424          */
425         BUFFER_TRACE(gd_bh, "get_write_access");
426         err = ext4_journal_get_write_access(handle, gd_bh);
427         if (err)
428                 goto error_return;
429         /*
430          * make sure we don't allow a parallel init on other groups in the
431          * same buddy cache
432          */
433         down_write(&grp->alloc_sem);
434         for (i = 0, blocks_freed = 0; i < count; i++) {
435                 BUFFER_TRACE(bitmap_bh, "clear bit");
436                 if (!ext4_clear_bit_atomic(sb_bgl_lock(sbi, block_group),
437                                                 bit + i, bitmap_bh->b_data)) {
438                         ext4_error(sb, __func__,
439                                    "bit already cleared for block %llu",
440                                    (ext4_fsblk_t)(block + i));
441                         BUFFER_TRACE(bitmap_bh, "bit already cleared");
442                 } else {
443                         blocks_freed++;
444                 }
445         }
446         spin_lock(sb_bgl_lock(sbi, block_group));
447         le16_add_cpu(&desc->bg_free_blocks_count, blocks_freed);
448         desc->bg_checksum = ext4_group_desc_csum(sbi, block_group, desc);
449         spin_unlock(sb_bgl_lock(sbi, block_group));
450         percpu_counter_add(&sbi->s_freeblocks_counter, blocks_freed);
451
452         if (sbi->s_log_groups_per_flex) {
453                 ext4_group_t flex_group = ext4_flex_group(sbi, block_group);
454                 spin_lock(sb_bgl_lock(sbi, flex_group));
455                 sbi->s_flex_groups[flex_group].free_blocks += blocks_freed;
456                 spin_unlock(sb_bgl_lock(sbi, flex_group));
457         }
458         /*
459          * request to reload the buddy with the
460          * new bitmap information
461          */
462         set_bit(EXT4_GROUP_INFO_NEED_INIT_BIT, &(grp->bb_state));
463         ext4_mb_update_group_info(grp, blocks_freed);
464         up_write(&grp->alloc_sem);
465
466         /* We dirtied the bitmap block */
467         BUFFER_TRACE(bitmap_bh, "dirtied bitmap block");
468         err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
469
470         /* And the group descriptor block */
471         BUFFER_TRACE(gd_bh, "dirtied group descriptor block");
472         ret = ext4_handle_dirty_metadata(handle, NULL, gd_bh);
473         if (!err)
474                 err = ret;
475         sb->s_dirt = 1;
476
477 error_return:
478         brelse(bitmap_bh);
479         ext4_std_error(sb, err);
480         return;
481 }
482
483 /**
484  * ext4_free_blocks() -- Free given blocks and update quota
485  * @handle:             handle for this transaction
486  * @inode:              inode
487  * @block:              start physical block to free
488  * @count:              number of blocks to count
489  * @metadata:           Are these metadata blocks
490  */
491 void ext4_free_blocks(handle_t *handle, struct inode *inode,
492                         ext4_fsblk_t block, unsigned long count,
493                         int metadata)
494 {
495         struct super_block *sb;
496         unsigned long dquot_freed_blocks;
497
498         /* this isn't the right place to decide whether block is metadata
499          * inode.c/extents.c knows better, but for safety ... */
500         if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode))
501                 metadata = 1;
502
503         /* We need to make sure we don't reuse
504          * block released untill the transaction commit.
505          * writeback mode have weak data consistency so
506          * don't force data as metadata when freeing block
507          * for writeback mode.
508          */
509         if (metadata == 0 && !ext4_should_writeback_data(inode))
510                 metadata = 1;
511
512         sb = inode->i_sb;
513
514         ext4_mb_free_blocks(handle, inode, block, count,
515                             metadata, &dquot_freed_blocks);
516         if (dquot_freed_blocks)
517                 DQUOT_FREE_BLOCK(inode, dquot_freed_blocks);
518         return;
519 }
520
521 /**
522  * ext4_has_free_blocks()
523  * @sbi:        in-core super block structure.
524  * @nblocks:    number of needed blocks
525  *
526  * Check if filesystem has nblocks free & available for allocation.
527  * On success return 1, return 0 on failure.
528  */
529 int ext4_has_free_blocks(struct ext4_sb_info *sbi, s64 nblocks)
530 {
531         s64 free_blocks, dirty_blocks, root_blocks;
532         struct percpu_counter *fbc = &sbi->s_freeblocks_counter;
533         struct percpu_counter *dbc = &sbi->s_dirtyblocks_counter;
534
535         free_blocks  = percpu_counter_read_positive(fbc);
536         dirty_blocks = percpu_counter_read_positive(dbc);
537         root_blocks = ext4_r_blocks_count(sbi->s_es);
538
539         if (free_blocks - (nblocks + root_blocks + dirty_blocks) <
540                                                 EXT4_FREEBLOCKS_WATERMARK) {
541                 free_blocks  = percpu_counter_sum_positive(fbc);
542                 dirty_blocks = percpu_counter_sum_positive(dbc);
543                 if (dirty_blocks < 0) {
544                         printk(KERN_CRIT "Dirty block accounting "
545                                         "went wrong %lld\n",
546                                         (long long)dirty_blocks);
547                 }
548         }
549         /* Check whether we have space after
550          * accounting for current dirty blocks & root reserved blocks.
551          */
552         if (free_blocks >= ((root_blocks + nblocks) + dirty_blocks))
553                 return 1;
554
555         /* Hm, nope.  Are (enough) root reserved blocks available? */
556         if (sbi->s_resuid == current_fsuid() ||
557             ((sbi->s_resgid != 0) && in_group_p(sbi->s_resgid)) ||
558             capable(CAP_SYS_RESOURCE)) {
559                 if (free_blocks >= (nblocks + dirty_blocks))
560                         return 1;
561         }
562
563         return 0;
564 }
565
566 int ext4_claim_free_blocks(struct ext4_sb_info *sbi,
567                                                 s64 nblocks)
568 {
569         if (ext4_has_free_blocks(sbi, nblocks)) {
570                 percpu_counter_add(&sbi->s_dirtyblocks_counter, nblocks);
571                 return 0;
572         } else
573                 return -ENOSPC;
574 }
575
576 /**
577  * ext4_should_retry_alloc()
578  * @sb:                 super block
579  * @retries             number of attemps has been made
580  *
581  * ext4_should_retry_alloc() is called when ENOSPC is returned, and if
582  * it is profitable to retry the operation, this function will wait
583  * for the current or commiting transaction to complete, and then
584  * return TRUE.
585  *
586  * if the total number of retries exceed three times, return FALSE.
587  */
588 int ext4_should_retry_alloc(struct super_block *sb, int *retries)
589 {
590         if (!ext4_has_free_blocks(EXT4_SB(sb), 1) || (*retries)++ > 3)
591                 return 0;
592
593         jbd_debug(1, "%s: retrying operation after ENOSPC\n", sb->s_id);
594
595         return jbd2_journal_force_commit_nested(EXT4_SB(sb)->s_journal);
596 }
597
598 /*
599  * ext4_new_meta_blocks() -- allocate block for meta data (indexing) blocks
600  *
601  * @handle:             handle to this transaction
602  * @inode:              file inode
603  * @goal:               given target block(filesystem wide)
604  * @count:              pointer to total number of blocks needed
605  * @errp:               error code
606  *
607  * Return 1st allocated block number on success, *count stores total account
608  * error stores in errp pointer
609  */
610 ext4_fsblk_t ext4_new_meta_blocks(handle_t *handle, struct inode *inode,
611                 ext4_fsblk_t goal, unsigned long *count, int *errp)
612 {
613         struct ext4_allocation_request ar;
614         ext4_fsblk_t ret;
615
616         memset(&ar, 0, sizeof(ar));
617         /* Fill with neighbour allocated blocks */
618         ar.inode = inode;
619         ar.goal = goal;
620         ar.len = count ? *count : 1;
621
622         ret = ext4_mb_new_blocks(handle, &ar, errp);
623         if (count)
624                 *count = ar.len;
625
626         /*
627          * Account for the allocated meta blocks
628          */
629         if (!(*errp) && EXT4_I(inode)->i_delalloc_reserved_flag) {
630                 spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
631                 EXT4_I(inode)->i_allocated_meta_blocks += ar.len;
632                 spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
633         }
634         return ret;
635 }
636
637 /**
638  * ext4_count_free_blocks() -- count filesystem free blocks
639  * @sb:         superblock
640  *
641  * Adds up the number of free blocks from each block group.
642  */
643 ext4_fsblk_t ext4_count_free_blocks(struct super_block *sb)
644 {
645         ext4_fsblk_t desc_count;
646         struct ext4_group_desc *gdp;
647         ext4_group_t i;
648         ext4_group_t ngroups = EXT4_SB(sb)->s_groups_count;
649 #ifdef EXT4FS_DEBUG
650         struct ext4_super_block *es;
651         ext4_fsblk_t bitmap_count;
652         unsigned int x;
653         struct buffer_head *bitmap_bh = NULL;
654
655         es = EXT4_SB(sb)->s_es;
656         desc_count = 0;
657         bitmap_count = 0;
658         gdp = NULL;
659
660         smp_rmb();
661         for (i = 0; i < ngroups; i++) {
662                 gdp = ext4_get_group_desc(sb, i, NULL);
663                 if (!gdp)
664                         continue;
665                 desc_count += le16_to_cpu(gdp->bg_free_blocks_count);
666                 brelse(bitmap_bh);
667                 bitmap_bh = ext4_read_block_bitmap(sb, i);
668                 if (bitmap_bh == NULL)
669                         continue;
670
671                 x = ext4_count_free(bitmap_bh, sb->s_blocksize);
672                 printk(KERN_DEBUG "group %lu: stored = %d, counted = %u\n",
673                         i, le16_to_cpu(gdp->bg_free_blocks_count), x);
674                 bitmap_count += x;
675         }
676         brelse(bitmap_bh);
677         printk(KERN_DEBUG "ext4_count_free_blocks: stored = %llu"
678                 ", computed = %llu, %llu\n", ext4_free_blocks_count(es),
679                desc_count, bitmap_count);
680         return bitmap_count;
681 #else
682         desc_count = 0;
683         smp_rmb();
684         for (i = 0; i < ngroups; i++) {
685                 gdp = ext4_get_group_desc(sb, i, NULL);
686                 if (!gdp)
687                         continue;
688                 desc_count += le16_to_cpu(gdp->bg_free_blocks_count);
689         }
690
691         return desc_count;
692 #endif
693 }
694
695 static inline int test_root(ext4_group_t a, int b)
696 {
697         int num = b;
698
699         while (a > num)
700                 num *= b;
701         return num == a;
702 }
703
704 static int ext4_group_sparse(ext4_group_t group)
705 {
706         if (group <= 1)
707                 return 1;
708         if (!(group & 1))
709                 return 0;
710         return (test_root(group, 7) || test_root(group, 5) ||
711                 test_root(group, 3));
712 }
713
714 /**
715  *      ext4_bg_has_super - number of blocks used by the superblock in group
716  *      @sb: superblock for filesystem
717  *      @group: group number to check
718  *
719  *      Return the number of blocks used by the superblock (primary or backup)
720  *      in this group.  Currently this will be only 0 or 1.
721  */
722 int ext4_bg_has_super(struct super_block *sb, ext4_group_t group)
723 {
724         if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
725                                 EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER) &&
726                         !ext4_group_sparse(group))
727                 return 0;
728         return 1;
729 }
730
731 static unsigned long ext4_bg_num_gdb_meta(struct super_block *sb,
732                                         ext4_group_t group)
733 {
734         unsigned long metagroup = group / EXT4_DESC_PER_BLOCK(sb);
735         ext4_group_t first = metagroup * EXT4_DESC_PER_BLOCK(sb);
736         ext4_group_t last = first + EXT4_DESC_PER_BLOCK(sb) - 1;
737
738         if (group == first || group == first + 1 || group == last)
739                 return 1;
740         return 0;
741 }
742
743 static unsigned long ext4_bg_num_gdb_nometa(struct super_block *sb,
744                                         ext4_group_t group)
745 {
746         return ext4_bg_has_super(sb, group) ? EXT4_SB(sb)->s_gdb_count : 0;
747 }
748
749 /**
750  *      ext4_bg_num_gdb - number of blocks used by the group table in group
751  *      @sb: superblock for filesystem
752  *      @group: group number to check
753  *
754  *      Return the number of blocks used by the group descriptor table
755  *      (primary or backup) in this group.  In the future there may be a
756  *      different number of descriptor blocks in each group.
757  */
758 unsigned long ext4_bg_num_gdb(struct super_block *sb, ext4_group_t group)
759 {
760         unsigned long first_meta_bg =
761                         le32_to_cpu(EXT4_SB(sb)->s_es->s_first_meta_bg);
762         unsigned long metagroup = group / EXT4_DESC_PER_BLOCK(sb);
763
764         if (!EXT4_HAS_INCOMPAT_FEATURE(sb,EXT4_FEATURE_INCOMPAT_META_BG) ||
765                         metagroup < first_meta_bg)
766                 return ext4_bg_num_gdb_nometa(sb, group);
767
768         return ext4_bg_num_gdb_meta(sb,group);
769
770 }
771