perf data: Add is_perf_data function
[linux-2.6-microblaze.git] / fs / ext4 / balloc.c
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  *  linux/fs/ext4/balloc.c
4  *
5  * Copyright (C) 1992, 1993, 1994, 1995
6  * Remy Card (card@masi.ibp.fr)
7  * Laboratoire MASI - Institut Blaise Pascal
8  * Universite Pierre et Marie Curie (Paris VI)
9  *
10  *  Enhanced block allocation by Stephen Tweedie (sct@redhat.com), 1993
11  *  Big-endian to little-endian byte-swapping/bitmaps by
12  *        David S. Miller (davem@caip.rutgers.edu), 1995
13  */
14
15 #include <linux/time.h>
16 #include <linux/capability.h>
17 #include <linux/fs.h>
18 #include <linux/quotaops.h>
19 #include <linux/buffer_head.h>
20 #include "ext4.h"
21 #include "ext4_jbd2.h"
22 #include "mballoc.h"
23
24 #include <trace/events/ext4.h>
25
26 static unsigned ext4_num_base_meta_clusters(struct super_block *sb,
27                                             ext4_group_t block_group);
28 /*
29  * balloc.c contains the blocks allocation and deallocation routines
30  */
31
32 /*
33  * Calculate block group number for a given block number
34  */
35 ext4_group_t ext4_get_group_number(struct super_block *sb,
36                                    ext4_fsblk_t block)
37 {
38         ext4_group_t group;
39
40         if (test_opt2(sb, STD_GROUP_SIZE))
41                 group = (block -
42                          le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block)) >>
43                         (EXT4_BLOCK_SIZE_BITS(sb) + EXT4_CLUSTER_BITS(sb) + 3);
44         else
45                 ext4_get_group_no_and_offset(sb, block, &group, NULL);
46         return group;
47 }
48
49 /*
50  * Calculate the block group number and offset into the block/cluster
51  * allocation bitmap, given a block number
52  */
53 void ext4_get_group_no_and_offset(struct super_block *sb, ext4_fsblk_t blocknr,
54                 ext4_group_t *blockgrpp, ext4_grpblk_t *offsetp)
55 {
56         struct ext4_super_block *es = EXT4_SB(sb)->s_es;
57         ext4_grpblk_t offset;
58
59         blocknr = blocknr - le32_to_cpu(es->s_first_data_block);
60         offset = do_div(blocknr, EXT4_BLOCKS_PER_GROUP(sb)) >>
61                 EXT4_SB(sb)->s_cluster_bits;
62         if (offsetp)
63                 *offsetp = offset;
64         if (blockgrpp)
65                 *blockgrpp = blocknr;
66
67 }
68
69 /*
70  * Check whether the 'block' lives within the 'block_group'. Returns 1 if so
71  * and 0 otherwise.
72  */
73 static inline int ext4_block_in_group(struct super_block *sb,
74                                       ext4_fsblk_t block,
75                                       ext4_group_t block_group)
76 {
77         ext4_group_t actual_group;
78
79         actual_group = ext4_get_group_number(sb, block);
80         return (actual_group == block_group) ? 1 : 0;
81 }
82
83 /* Return the number of clusters used for file system metadata; this
84  * represents the overhead needed by the file system.
85  */
86 static unsigned ext4_num_overhead_clusters(struct super_block *sb,
87                                            ext4_group_t block_group,
88                                            struct ext4_group_desc *gdp)
89 {
90         unsigned num_clusters;
91         int block_cluster = -1, inode_cluster = -1, itbl_cluster = -1, i, c;
92         ext4_fsblk_t start = ext4_group_first_block_no(sb, block_group);
93         ext4_fsblk_t itbl_blk;
94         struct ext4_sb_info *sbi = EXT4_SB(sb);
95
96         /* This is the number of clusters used by the superblock,
97          * block group descriptors, and reserved block group
98          * descriptor blocks */
99         num_clusters = ext4_num_base_meta_clusters(sb, block_group);
100
101         /*
102          * For the allocation bitmaps and inode table, we first need
103          * to check to see if the block is in the block group.  If it
104          * is, then check to see if the cluster is already accounted
105          * for in the clusters used for the base metadata cluster, or
106          * if we can increment the base metadata cluster to include
107          * that block.  Otherwise, we will have to track the cluster
108          * used for the allocation bitmap or inode table explicitly.
109          * Normally all of these blocks are contiguous, so the special
110          * case handling shouldn't be necessary except for *very*
111          * unusual file system layouts.
112          */
113         if (ext4_block_in_group(sb, ext4_block_bitmap(sb, gdp), block_group)) {
114                 block_cluster = EXT4_B2C(sbi,
115                                          ext4_block_bitmap(sb, gdp) - start);
116                 if (block_cluster < num_clusters)
117                         block_cluster = -1;
118                 else if (block_cluster == num_clusters) {
119                         num_clusters++;
120                         block_cluster = -1;
121                 }
122         }
123
124         if (ext4_block_in_group(sb, ext4_inode_bitmap(sb, gdp), block_group)) {
125                 inode_cluster = EXT4_B2C(sbi,
126                                          ext4_inode_bitmap(sb, gdp) - start);
127                 if (inode_cluster < num_clusters)
128                         inode_cluster = -1;
129                 else if (inode_cluster == num_clusters) {
130                         num_clusters++;
131                         inode_cluster = -1;
132                 }
133         }
134
135         itbl_blk = ext4_inode_table(sb, gdp);
136         for (i = 0; i < sbi->s_itb_per_group; i++) {
137                 if (ext4_block_in_group(sb, itbl_blk + i, block_group)) {
138                         c = EXT4_B2C(sbi, itbl_blk + i - start);
139                         if ((c < num_clusters) || (c == inode_cluster) ||
140                             (c == block_cluster) || (c == itbl_cluster))
141                                 continue;
142                         if (c == num_clusters) {
143                                 num_clusters++;
144                                 continue;
145                         }
146                         num_clusters++;
147                         itbl_cluster = c;
148                 }
149         }
150
151         if (block_cluster != -1)
152                 num_clusters++;
153         if (inode_cluster != -1)
154                 num_clusters++;
155
156         return num_clusters;
157 }
158
159 static unsigned int num_clusters_in_group(struct super_block *sb,
160                                           ext4_group_t block_group)
161 {
162         unsigned int blocks;
163
164         if (block_group == ext4_get_groups_count(sb) - 1) {
165                 /*
166                  * Even though mke2fs always initializes the first and
167                  * last group, just in case some other tool was used,
168                  * we need to make sure we calculate the right free
169                  * blocks.
170                  */
171                 blocks = ext4_blocks_count(EXT4_SB(sb)->s_es) -
172                         ext4_group_first_block_no(sb, block_group);
173         } else
174                 blocks = EXT4_BLOCKS_PER_GROUP(sb);
175         return EXT4_NUM_B2C(EXT4_SB(sb), blocks);
176 }
177
178 /* Initializes an uninitialized block bitmap */
179 static int ext4_init_block_bitmap(struct super_block *sb,
180                                    struct buffer_head *bh,
181                                    ext4_group_t block_group,
182                                    struct ext4_group_desc *gdp)
183 {
184         unsigned int bit, bit_max;
185         struct ext4_sb_info *sbi = EXT4_SB(sb);
186         ext4_fsblk_t start, tmp;
187
188         J_ASSERT_BH(bh, buffer_locked(bh));
189
190         /* If checksum is bad mark all blocks used to prevent allocation
191          * essentially implementing a per-group read-only flag. */
192         if (!ext4_group_desc_csum_verify(sb, block_group, gdp)) {
193                 ext4_mark_group_bitmap_corrupted(sb, block_group,
194                                         EXT4_GROUP_INFO_BBITMAP_CORRUPT |
195                                         EXT4_GROUP_INFO_IBITMAP_CORRUPT);
196                 return -EFSBADCRC;
197         }
198         memset(bh->b_data, 0, sb->s_blocksize);
199
200         bit_max = ext4_num_base_meta_clusters(sb, block_group);
201         if ((bit_max >> 3) >= bh->b_size)
202                 return -EFSCORRUPTED;
203
204         for (bit = 0; bit < bit_max; bit++)
205                 ext4_set_bit(bit, bh->b_data);
206
207         start = ext4_group_first_block_no(sb, block_group);
208
209         /* Set bits for block and inode bitmaps, and inode table */
210         tmp = ext4_block_bitmap(sb, gdp);
211         if (ext4_block_in_group(sb, tmp, block_group))
212                 ext4_set_bit(EXT4_B2C(sbi, tmp - start), bh->b_data);
213
214         tmp = ext4_inode_bitmap(sb, gdp);
215         if (ext4_block_in_group(sb, tmp, block_group))
216                 ext4_set_bit(EXT4_B2C(sbi, tmp - start), bh->b_data);
217
218         tmp = ext4_inode_table(sb, gdp);
219         for (; tmp < ext4_inode_table(sb, gdp) +
220                      sbi->s_itb_per_group; tmp++) {
221                 if (ext4_block_in_group(sb, tmp, block_group))
222                         ext4_set_bit(EXT4_B2C(sbi, tmp - start), bh->b_data);
223         }
224
225         /*
226          * Also if the number of blocks within the group is less than
227          * the blocksize * 8 ( which is the size of bitmap ), set rest
228          * of the block bitmap to 1
229          */
230         ext4_mark_bitmap_end(num_clusters_in_group(sb, block_group),
231                              sb->s_blocksize * 8, bh->b_data);
232         return 0;
233 }
234
235 /* Return the number of free blocks in a block group.  It is used when
236  * the block bitmap is uninitialized, so we can't just count the bits
237  * in the bitmap. */
238 unsigned ext4_free_clusters_after_init(struct super_block *sb,
239                                        ext4_group_t block_group,
240                                        struct ext4_group_desc *gdp)
241 {
242         return num_clusters_in_group(sb, block_group) - 
243                 ext4_num_overhead_clusters(sb, block_group, gdp);
244 }
245
246 /*
247  * The free blocks are managed by bitmaps.  A file system contains several
248  * blocks groups.  Each group contains 1 bitmap block for blocks, 1 bitmap
249  * block for inodes, N blocks for the inode table and data blocks.
250  *
251  * The file system contains group descriptors which are located after the
252  * super block.  Each descriptor contains the number of the bitmap block and
253  * the free blocks count in the block.  The descriptors are loaded in memory
254  * when a file system is mounted (see ext4_fill_super).
255  */
256
257 /**
258  * ext4_get_group_desc() -- load group descriptor from disk
259  * @sb:                 super block
260  * @block_group:        given block group
261  * @bh:                 pointer to the buffer head to store the block
262  *                      group descriptor
263  */
264 struct ext4_group_desc * ext4_get_group_desc(struct super_block *sb,
265                                              ext4_group_t block_group,
266                                              struct buffer_head **bh)
267 {
268         unsigned int group_desc;
269         unsigned int offset;
270         ext4_group_t ngroups = ext4_get_groups_count(sb);
271         struct ext4_group_desc *desc;
272         struct ext4_sb_info *sbi = EXT4_SB(sb);
273         struct buffer_head *bh_p;
274
275         if (block_group >= ngroups) {
276                 ext4_error(sb, "block_group >= groups_count - block_group = %u,"
277                            " groups_count = %u", block_group, ngroups);
278
279                 return NULL;
280         }
281
282         group_desc = block_group >> EXT4_DESC_PER_BLOCK_BITS(sb);
283         offset = block_group & (EXT4_DESC_PER_BLOCK(sb) - 1);
284         bh_p = sbi_array_rcu_deref(sbi, s_group_desc, group_desc);
285         /*
286          * sbi_array_rcu_deref returns with rcu unlocked, this is ok since
287          * the pointer being dereferenced won't be dereferenced again. By
288          * looking at the usage in add_new_gdb() the value isn't modified,
289          * just the pointer, and so it remains valid.
290          */
291         if (!bh_p) {
292                 ext4_error(sb, "Group descriptor not loaded - "
293                            "block_group = %u, group_desc = %u, desc = %u",
294                            block_group, group_desc, offset);
295                 return NULL;
296         }
297
298         desc = (struct ext4_group_desc *)(
299                 (__u8 *)bh_p->b_data +
300                 offset * EXT4_DESC_SIZE(sb));
301         if (bh)
302                 *bh = bh_p;
303         return desc;
304 }
305
306 /*
307  * Return the block number which was discovered to be invalid, or 0 if
308  * the block bitmap is valid.
309  */
310 static ext4_fsblk_t ext4_valid_block_bitmap(struct super_block *sb,
311                                             struct ext4_group_desc *desc,
312                                             ext4_group_t block_group,
313                                             struct buffer_head *bh)
314 {
315         struct ext4_sb_info *sbi = EXT4_SB(sb);
316         ext4_grpblk_t offset;
317         ext4_grpblk_t next_zero_bit;
318         ext4_grpblk_t max_bit = EXT4_CLUSTERS_PER_GROUP(sb);
319         ext4_fsblk_t blk;
320         ext4_fsblk_t group_first_block;
321
322         if (ext4_has_feature_flex_bg(sb)) {
323                 /* with FLEX_BG, the inode/block bitmaps and itable
324                  * blocks may not be in the group at all
325                  * so the bitmap validation will be skipped for those groups
326                  * or it has to also read the block group where the bitmaps
327                  * are located to verify they are set.
328                  */
329                 return 0;
330         }
331         group_first_block = ext4_group_first_block_no(sb, block_group);
332
333         /* check whether block bitmap block number is set */
334         blk = ext4_block_bitmap(sb, desc);
335         offset = blk - group_first_block;
336         if (offset < 0 || EXT4_B2C(sbi, offset) >= max_bit ||
337             !ext4_test_bit(EXT4_B2C(sbi, offset), bh->b_data))
338                 /* bad block bitmap */
339                 return blk;
340
341         /* check whether the inode bitmap block number is set */
342         blk = ext4_inode_bitmap(sb, desc);
343         offset = blk - group_first_block;
344         if (offset < 0 || EXT4_B2C(sbi, offset) >= max_bit ||
345             !ext4_test_bit(EXT4_B2C(sbi, offset), bh->b_data))
346                 /* bad block bitmap */
347                 return blk;
348
349         /* check whether the inode table block number is set */
350         blk = ext4_inode_table(sb, desc);
351         offset = blk - group_first_block;
352         if (offset < 0 || EXT4_B2C(sbi, offset) >= max_bit ||
353             EXT4_B2C(sbi, offset + sbi->s_itb_per_group) >= max_bit)
354                 return blk;
355         next_zero_bit = ext4_find_next_zero_bit(bh->b_data,
356                         EXT4_B2C(sbi, offset + sbi->s_itb_per_group),
357                         EXT4_B2C(sbi, offset));
358         if (next_zero_bit <
359             EXT4_B2C(sbi, offset + sbi->s_itb_per_group))
360                 /* bad bitmap for inode tables */
361                 return blk;
362         return 0;
363 }
364
365 static int ext4_validate_block_bitmap(struct super_block *sb,
366                                       struct ext4_group_desc *desc,
367                                       ext4_group_t block_group,
368                                       struct buffer_head *bh)
369 {
370         ext4_fsblk_t    blk;
371         struct ext4_group_info *grp;
372
373         if (EXT4_SB(sb)->s_mount_state & EXT4_FC_REPLAY)
374                 return 0;
375
376         grp = ext4_get_group_info(sb, block_group);
377
378         if (buffer_verified(bh))
379                 return 0;
380         if (EXT4_MB_GRP_BBITMAP_CORRUPT(grp))
381                 return -EFSCORRUPTED;
382
383         ext4_lock_group(sb, block_group);
384         if (buffer_verified(bh))
385                 goto verified;
386         if (unlikely(!ext4_block_bitmap_csum_verify(sb, block_group,
387                                                     desc, bh) ||
388                      ext4_simulate_fail(sb, EXT4_SIM_BBITMAP_CRC))) {
389                 ext4_unlock_group(sb, block_group);
390                 ext4_error(sb, "bg %u: bad block bitmap checksum", block_group);
391                 ext4_mark_group_bitmap_corrupted(sb, block_group,
392                                         EXT4_GROUP_INFO_BBITMAP_CORRUPT);
393                 return -EFSBADCRC;
394         }
395         blk = ext4_valid_block_bitmap(sb, desc, block_group, bh);
396         if (unlikely(blk != 0)) {
397                 ext4_unlock_group(sb, block_group);
398                 ext4_error(sb, "bg %u: block %llu: invalid block bitmap",
399                            block_group, blk);
400                 ext4_mark_group_bitmap_corrupted(sb, block_group,
401                                         EXT4_GROUP_INFO_BBITMAP_CORRUPT);
402                 return -EFSCORRUPTED;
403         }
404         set_buffer_verified(bh);
405 verified:
406         ext4_unlock_group(sb, block_group);
407         return 0;
408 }
409
410 /**
411  * ext4_read_block_bitmap_nowait()
412  * @sb:                 super block
413  * @block_group:        given block group
414  *
415  * Read the bitmap for a given block_group,and validate the
416  * bits for block/inode/inode tables are set in the bitmaps
417  *
418  * Return buffer_head on success or an ERR_PTR in case of failure.
419  */
420 struct buffer_head *
421 ext4_read_block_bitmap_nowait(struct super_block *sb, ext4_group_t block_group,
422                               bool ignore_locked)
423 {
424         struct ext4_group_desc *desc;
425         struct ext4_sb_info *sbi = EXT4_SB(sb);
426         struct buffer_head *bh;
427         ext4_fsblk_t bitmap_blk;
428         int err;
429
430         desc = ext4_get_group_desc(sb, block_group, NULL);
431         if (!desc)
432                 return ERR_PTR(-EFSCORRUPTED);
433         bitmap_blk = ext4_block_bitmap(sb, desc);
434         if ((bitmap_blk <= le32_to_cpu(sbi->s_es->s_first_data_block)) ||
435             (bitmap_blk >= ext4_blocks_count(sbi->s_es))) {
436                 ext4_error(sb, "Invalid block bitmap block %llu in "
437                            "block_group %u", bitmap_blk, block_group);
438                 ext4_mark_group_bitmap_corrupted(sb, block_group,
439                                         EXT4_GROUP_INFO_BBITMAP_CORRUPT);
440                 return ERR_PTR(-EFSCORRUPTED);
441         }
442         bh = sb_getblk(sb, bitmap_blk);
443         if (unlikely(!bh)) {
444                 ext4_warning(sb, "Cannot get buffer for block bitmap - "
445                              "block_group = %u, block_bitmap = %llu",
446                              block_group, bitmap_blk);
447                 return ERR_PTR(-ENOMEM);
448         }
449
450         if (ignore_locked && buffer_locked(bh)) {
451                 /* buffer under IO already, return if called for prefetching */
452                 put_bh(bh);
453                 return NULL;
454         }
455
456         if (bitmap_uptodate(bh))
457                 goto verify;
458
459         lock_buffer(bh);
460         if (bitmap_uptodate(bh)) {
461                 unlock_buffer(bh);
462                 goto verify;
463         }
464         ext4_lock_group(sb, block_group);
465         if (ext4_has_group_desc_csum(sb) &&
466             (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT))) {
467                 if (block_group == 0) {
468                         ext4_unlock_group(sb, block_group);
469                         unlock_buffer(bh);
470                         ext4_error(sb, "Block bitmap for bg 0 marked "
471                                    "uninitialized");
472                         err = -EFSCORRUPTED;
473                         goto out;
474                 }
475                 err = ext4_init_block_bitmap(sb, bh, block_group, desc);
476                 set_bitmap_uptodate(bh);
477                 set_buffer_uptodate(bh);
478                 set_buffer_verified(bh);
479                 ext4_unlock_group(sb, block_group);
480                 unlock_buffer(bh);
481                 if (err) {
482                         ext4_error(sb, "Failed to init block bitmap for group "
483                                    "%u: %d", block_group, err);
484                         goto out;
485                 }
486                 goto verify;
487         }
488         ext4_unlock_group(sb, block_group);
489         if (buffer_uptodate(bh)) {
490                 /*
491                  * if not uninit if bh is uptodate,
492                  * bitmap is also uptodate
493                  */
494                 set_bitmap_uptodate(bh);
495                 unlock_buffer(bh);
496                 goto verify;
497         }
498         /*
499          * submit the buffer_head for reading
500          */
501         set_buffer_new(bh);
502         trace_ext4_read_block_bitmap_load(sb, block_group, ignore_locked);
503         ext4_read_bh_nowait(bh, REQ_META | REQ_PRIO |
504                             (ignore_locked ? REQ_RAHEAD : 0),
505                             ext4_end_bitmap_read);
506         return bh;
507 verify:
508         err = ext4_validate_block_bitmap(sb, desc, block_group, bh);
509         if (err)
510                 goto out;
511         return bh;
512 out:
513         put_bh(bh);
514         return ERR_PTR(err);
515 }
516
517 /* Returns 0 on success, -errno on error */
518 int ext4_wait_block_bitmap(struct super_block *sb, ext4_group_t block_group,
519                            struct buffer_head *bh)
520 {
521         struct ext4_group_desc *desc;
522
523         if (!buffer_new(bh))
524                 return 0;
525         desc = ext4_get_group_desc(sb, block_group, NULL);
526         if (!desc)
527                 return -EFSCORRUPTED;
528         wait_on_buffer(bh);
529         ext4_simulate_fail_bh(sb, bh, EXT4_SIM_BBITMAP_EIO);
530         if (!buffer_uptodate(bh)) {
531                 ext4_error_err(sb, EIO, "Cannot read block bitmap - "
532                                "block_group = %u, block_bitmap = %llu",
533                                block_group, (unsigned long long) bh->b_blocknr);
534                 ext4_mark_group_bitmap_corrupted(sb, block_group,
535                                         EXT4_GROUP_INFO_BBITMAP_CORRUPT);
536                 return -EIO;
537         }
538         clear_buffer_new(bh);
539         /* Panic or remount fs read-only if block bitmap is invalid */
540         return ext4_validate_block_bitmap(sb, desc, block_group, bh);
541 }
542
543 struct buffer_head *
544 ext4_read_block_bitmap(struct super_block *sb, ext4_group_t block_group)
545 {
546         struct buffer_head *bh;
547         int err;
548
549         bh = ext4_read_block_bitmap_nowait(sb, block_group, false);
550         if (IS_ERR(bh))
551                 return bh;
552         err = ext4_wait_block_bitmap(sb, block_group, bh);
553         if (err) {
554                 put_bh(bh);
555                 return ERR_PTR(err);
556         }
557         return bh;
558 }
559
560 /**
561  * ext4_has_free_clusters()
562  * @sbi:        in-core super block structure.
563  * @nclusters:  number of needed blocks
564  * @flags:      flags from ext4_mb_new_blocks()
565  *
566  * Check if filesystem has nclusters free & available for allocation.
567  * On success return 1, return 0 on failure.
568  */
569 static int ext4_has_free_clusters(struct ext4_sb_info *sbi,
570                                   s64 nclusters, unsigned int flags)
571 {
572         s64 free_clusters, dirty_clusters, rsv, resv_clusters;
573         struct percpu_counter *fcc = &sbi->s_freeclusters_counter;
574         struct percpu_counter *dcc = &sbi->s_dirtyclusters_counter;
575
576         free_clusters  = percpu_counter_read_positive(fcc);
577         dirty_clusters = percpu_counter_read_positive(dcc);
578         resv_clusters = atomic64_read(&sbi->s_resv_clusters);
579
580         /*
581          * r_blocks_count should always be multiple of the cluster ratio so
582          * we are safe to do a plane bit shift only.
583          */
584         rsv = (ext4_r_blocks_count(sbi->s_es) >> sbi->s_cluster_bits) +
585               resv_clusters;
586
587         if (free_clusters - (nclusters + rsv + dirty_clusters) <
588                                         EXT4_FREECLUSTERS_WATERMARK) {
589                 free_clusters  = percpu_counter_sum_positive(fcc);
590                 dirty_clusters = percpu_counter_sum_positive(dcc);
591         }
592         /* Check whether we have space after accounting for current
593          * dirty clusters & root reserved clusters.
594          */
595         if (free_clusters >= (rsv + nclusters + dirty_clusters))
596                 return 1;
597
598         /* Hm, nope.  Are (enough) root reserved clusters available? */
599         if (uid_eq(sbi->s_resuid, current_fsuid()) ||
600             (!gid_eq(sbi->s_resgid, GLOBAL_ROOT_GID) && in_group_p(sbi->s_resgid)) ||
601             capable(CAP_SYS_RESOURCE) ||
602             (flags & EXT4_MB_USE_ROOT_BLOCKS)) {
603
604                 if (free_clusters >= (nclusters + dirty_clusters +
605                                       resv_clusters))
606                         return 1;
607         }
608         /* No free blocks. Let's see if we can dip into reserved pool */
609         if (flags & EXT4_MB_USE_RESERVED) {
610                 if (free_clusters >= (nclusters + dirty_clusters))
611                         return 1;
612         }
613
614         return 0;
615 }
616
617 int ext4_claim_free_clusters(struct ext4_sb_info *sbi,
618                              s64 nclusters, unsigned int flags)
619 {
620         if (ext4_has_free_clusters(sbi, nclusters, flags)) {
621                 percpu_counter_add(&sbi->s_dirtyclusters_counter, nclusters);
622                 return 0;
623         } else
624                 return -ENOSPC;
625 }
626
627 /**
628  * ext4_should_retry_alloc() - check if a block allocation should be retried
629  * @sb:                 super block
630  * @retries:            number of attemps has been made
631  *
632  * ext4_should_retry_alloc() is called when ENOSPC is returned, and if
633  * it is profitable to retry the operation, this function will wait
634  * for the current or committing transaction to complete, and then
635  * return TRUE.  We will only retry once.
636  */
637 int ext4_should_retry_alloc(struct super_block *sb, int *retries)
638 {
639         if (!ext4_has_free_clusters(EXT4_SB(sb), 1, 0) ||
640             (*retries)++ > 1 ||
641             !EXT4_SB(sb)->s_journal)
642                 return 0;
643
644         smp_mb();
645         if (EXT4_SB(sb)->s_mb_free_pending == 0)
646                 return 0;
647
648         jbd_debug(1, "%s: retrying operation after ENOSPC\n", sb->s_id);
649         jbd2_journal_force_commit_nested(EXT4_SB(sb)->s_journal);
650         return 1;
651 }
652
653 /*
654  * ext4_new_meta_blocks() -- allocate block for meta data (indexing) blocks
655  *
656  * @handle:             handle to this transaction
657  * @inode:              file inode
658  * @goal:               given target block(filesystem wide)
659  * @count:              pointer to total number of clusters needed
660  * @errp:               error code
661  *
662  * Return 1st allocated block number on success, *count stores total account
663  * error stores in errp pointer
664  */
665 ext4_fsblk_t ext4_new_meta_blocks(handle_t *handle, struct inode *inode,
666                                   ext4_fsblk_t goal, unsigned int flags,
667                                   unsigned long *count, int *errp)
668 {
669         struct ext4_allocation_request ar;
670         ext4_fsblk_t ret;
671
672         memset(&ar, 0, sizeof(ar));
673         /* Fill with neighbour allocated blocks */
674         ar.inode = inode;
675         ar.goal = goal;
676         ar.len = count ? *count : 1;
677         ar.flags = flags;
678
679         ret = ext4_mb_new_blocks(handle, &ar, errp);
680         if (count)
681                 *count = ar.len;
682         /*
683          * Account for the allocated meta blocks.  We will never
684          * fail EDQUOT for metdata, but we do account for it.
685          */
686         if (!(*errp) && (flags & EXT4_MB_DELALLOC_RESERVED)) {
687                 dquot_alloc_block_nofail(inode,
688                                 EXT4_C2B(EXT4_SB(inode->i_sb), ar.len));
689         }
690         return ret;
691 }
692
693 /**
694  * ext4_count_free_clusters() -- count filesystem free clusters
695  * @sb:         superblock
696  *
697  * Adds up the number of free clusters from each block group.
698  */
699 ext4_fsblk_t ext4_count_free_clusters(struct super_block *sb)
700 {
701         ext4_fsblk_t desc_count;
702         struct ext4_group_desc *gdp;
703         ext4_group_t i;
704         ext4_group_t ngroups = ext4_get_groups_count(sb);
705         struct ext4_group_info *grp;
706 #ifdef EXT4FS_DEBUG
707         struct ext4_super_block *es;
708         ext4_fsblk_t bitmap_count;
709         unsigned int x;
710         struct buffer_head *bitmap_bh = NULL;
711
712         es = EXT4_SB(sb)->s_es;
713         desc_count = 0;
714         bitmap_count = 0;
715         gdp = NULL;
716
717         for (i = 0; i < ngroups; i++) {
718                 gdp = ext4_get_group_desc(sb, i, NULL);
719                 if (!gdp)
720                         continue;
721                 grp = NULL;
722                 if (EXT4_SB(sb)->s_group_info)
723                         grp = ext4_get_group_info(sb, i);
724                 if (!grp || !EXT4_MB_GRP_BBITMAP_CORRUPT(grp))
725                         desc_count += ext4_free_group_clusters(sb, gdp);
726                 brelse(bitmap_bh);
727                 bitmap_bh = ext4_read_block_bitmap(sb, i);
728                 if (IS_ERR(bitmap_bh)) {
729                         bitmap_bh = NULL;
730                         continue;
731                 }
732
733                 x = ext4_count_free(bitmap_bh->b_data,
734                                     EXT4_CLUSTERS_PER_GROUP(sb) / 8);
735                 printk(KERN_DEBUG "group %u: stored = %d, counted = %u\n",
736                         i, ext4_free_group_clusters(sb, gdp), x);
737                 bitmap_count += x;
738         }
739         brelse(bitmap_bh);
740         printk(KERN_DEBUG "ext4_count_free_clusters: stored = %llu"
741                ", computed = %llu, %llu\n",
742                EXT4_NUM_B2C(EXT4_SB(sb), ext4_free_blocks_count(es)),
743                desc_count, bitmap_count);
744         return bitmap_count;
745 #else
746         desc_count = 0;
747         for (i = 0; i < ngroups; i++) {
748                 gdp = ext4_get_group_desc(sb, i, NULL);
749                 if (!gdp)
750                         continue;
751                 grp = NULL;
752                 if (EXT4_SB(sb)->s_group_info)
753                         grp = ext4_get_group_info(sb, i);
754                 if (!grp || !EXT4_MB_GRP_BBITMAP_CORRUPT(grp))
755                         desc_count += ext4_free_group_clusters(sb, gdp);
756         }
757
758         return desc_count;
759 #endif
760 }
761
762 static inline int test_root(ext4_group_t a, int b)
763 {
764         while (1) {
765                 if (a < b)
766                         return 0;
767                 if (a == b)
768                         return 1;
769                 if ((a % b) != 0)
770                         return 0;
771                 a = a / b;
772         }
773 }
774
775 /**
776  *      ext4_bg_has_super - number of blocks used by the superblock in group
777  *      @sb: superblock for filesystem
778  *      @group: group number to check
779  *
780  *      Return the number of blocks used by the superblock (primary or backup)
781  *      in this group.  Currently this will be only 0 or 1.
782  */
783 int ext4_bg_has_super(struct super_block *sb, ext4_group_t group)
784 {
785         struct ext4_super_block *es = EXT4_SB(sb)->s_es;
786
787         if (group == 0)
788                 return 1;
789         if (ext4_has_feature_sparse_super2(sb)) {
790                 if (group == le32_to_cpu(es->s_backup_bgs[0]) ||
791                     group == le32_to_cpu(es->s_backup_bgs[1]))
792                         return 1;
793                 return 0;
794         }
795         if ((group <= 1) || !ext4_has_feature_sparse_super(sb))
796                 return 1;
797         if (!(group & 1))
798                 return 0;
799         if (test_root(group, 3) || (test_root(group, 5)) ||
800             test_root(group, 7))
801                 return 1;
802
803         return 0;
804 }
805
806 static unsigned long ext4_bg_num_gdb_meta(struct super_block *sb,
807                                         ext4_group_t group)
808 {
809         unsigned long metagroup = group / EXT4_DESC_PER_BLOCK(sb);
810         ext4_group_t first = metagroup * EXT4_DESC_PER_BLOCK(sb);
811         ext4_group_t last = first + EXT4_DESC_PER_BLOCK(sb) - 1;
812
813         if (group == first || group == first + 1 || group == last)
814                 return 1;
815         return 0;
816 }
817
818 static unsigned long ext4_bg_num_gdb_nometa(struct super_block *sb,
819                                         ext4_group_t group)
820 {
821         if (!ext4_bg_has_super(sb, group))
822                 return 0;
823
824         if (ext4_has_feature_meta_bg(sb))
825                 return le32_to_cpu(EXT4_SB(sb)->s_es->s_first_meta_bg);
826         else
827                 return EXT4_SB(sb)->s_gdb_count;
828 }
829
830 /**
831  *      ext4_bg_num_gdb - number of blocks used by the group table in group
832  *      @sb: superblock for filesystem
833  *      @group: group number to check
834  *
835  *      Return the number of blocks used by the group descriptor table
836  *      (primary or backup) in this group.  In the future there may be a
837  *      different number of descriptor blocks in each group.
838  */
839 unsigned long ext4_bg_num_gdb(struct super_block *sb, ext4_group_t group)
840 {
841         unsigned long first_meta_bg =
842                         le32_to_cpu(EXT4_SB(sb)->s_es->s_first_meta_bg);
843         unsigned long metagroup = group / EXT4_DESC_PER_BLOCK(sb);
844
845         if (!ext4_has_feature_meta_bg(sb) || metagroup < first_meta_bg)
846                 return ext4_bg_num_gdb_nometa(sb, group);
847
848         return ext4_bg_num_gdb_meta(sb,group);
849
850 }
851
852 /*
853  * This function returns the number of file system metadata clusters at
854  * the beginning of a block group, including the reserved gdt blocks.
855  */
856 static unsigned ext4_num_base_meta_clusters(struct super_block *sb,
857                                      ext4_group_t block_group)
858 {
859         struct ext4_sb_info *sbi = EXT4_SB(sb);
860         unsigned num;
861
862         /* Check for superblock and gdt backups in this group */
863         num = ext4_bg_has_super(sb, block_group);
864
865         if (!ext4_has_feature_meta_bg(sb) ||
866             block_group < le32_to_cpu(sbi->s_es->s_first_meta_bg) *
867                           sbi->s_desc_per_block) {
868                 if (num) {
869                         num += ext4_bg_num_gdb(sb, block_group);
870                         num += le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks);
871                 }
872         } else { /* For META_BG_BLOCK_GROUPS */
873                 num += ext4_bg_num_gdb(sb, block_group);
874         }
875         return EXT4_NUM_B2C(sbi, num);
876 }
877 /**
878  *      ext4_inode_to_goal_block - return a hint for block allocation
879  *      @inode: inode for block allocation
880  *
881  *      Return the ideal location to start allocating blocks for a
882  *      newly created inode.
883  */
884 ext4_fsblk_t ext4_inode_to_goal_block(struct inode *inode)
885 {
886         struct ext4_inode_info *ei = EXT4_I(inode);
887         ext4_group_t block_group;
888         ext4_grpblk_t colour;
889         int flex_size = ext4_flex_bg_size(EXT4_SB(inode->i_sb));
890         ext4_fsblk_t bg_start;
891         ext4_fsblk_t last_block;
892
893         block_group = ei->i_block_group;
894         if (flex_size >= EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME) {
895                 /*
896                  * If there are at least EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME
897                  * block groups per flexgroup, reserve the first block
898                  * group for directories and special files.  Regular
899                  * files will start at the second block group.  This
900                  * tends to speed up directory access and improves
901                  * fsck times.
902                  */
903                 block_group &= ~(flex_size-1);
904                 if (S_ISREG(inode->i_mode))
905                         block_group++;
906         }
907         bg_start = ext4_group_first_block_no(inode->i_sb, block_group);
908         last_block = ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es) - 1;
909
910         /*
911          * If we are doing delayed allocation, we don't need take
912          * colour into account.
913          */
914         if (test_opt(inode->i_sb, DELALLOC))
915                 return bg_start;
916
917         if (bg_start + EXT4_BLOCKS_PER_GROUP(inode->i_sb) <= last_block)
918                 colour = (task_pid_nr(current) % 16) *
919                         (EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16);
920         else
921                 colour = (task_pid_nr(current) % 16) *
922                         ((last_block - bg_start) / 16);
923         return bg_start + colour;
924 }
925