Commit | Line | Data |
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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
ac27a0ec | 2 | /* |
617ba13b | 3 | * linux/fs/ext4/balloc.c |
ac27a0ec DK |
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> | |
ac27a0ec DK |
18 | #include <linux/quotaops.h> |
19 | #include <linux/buffer_head.h> | |
3dcf5451 CH |
20 | #include "ext4.h" |
21 | #include "ext4_jbd2.h" | |
e21675d4 | 22 | #include "mballoc.h" |
3dcf5451 | 23 | |
0562e0ba JZ |
24 | #include <trace/events/ext4.h> |
25 | ||
5f163cc7 ES |
26 | static unsigned ext4_num_base_meta_clusters(struct super_block *sb, |
27 | ext4_group_t block_group); | |
ac27a0ec DK |
28 | /* |
29 | * balloc.c contains the blocks allocation and deallocation routines | |
30 | */ | |
31 | ||
bd86298e LC |
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)) | |
960fd856 TT |
41 | group = (block - |
42 | le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block)) >> | |
bd86298e LC |
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 | ||
72b64b59 | 49 | /* |
3212a80a TT |
50 | * Calculate the block group number and offset into the block/cluster |
51 | * allocation bitmap, given a block number | |
72b64b59 AM |
52 | */ |
53 | void ext4_get_group_no_and_offset(struct super_block *sb, ext4_fsblk_t blocknr, | |
fd2d4291 | 54 | ext4_group_t *blockgrpp, ext4_grpblk_t *offsetp) |
72b64b59 | 55 | { |
8c55e204 | 56 | struct ext4_super_block *es = EXT4_SB(sb)->s_es; |
72b64b59 AM |
57 | ext4_grpblk_t offset; |
58 | ||
8c55e204 | 59 | blocknr = blocknr - le32_to_cpu(es->s_first_data_block); |
3212a80a TT |
60 | offset = do_div(blocknr, EXT4_BLOCKS_PER_GROUP(sb)) >> |
61 | EXT4_SB(sb)->s_cluster_bits; | |
72b64b59 AM |
62 | if (offsetp) |
63 | *offsetp = offset; | |
64 | if (blockgrpp) | |
8c55e204 | 65 | *blockgrpp = blocknr; |
72b64b59 AM |
66 | |
67 | } | |
68 | ||
68911009 LC |
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) | |
0bf7e837 JS |
76 | { |
77 | ext4_group_t actual_group; | |
68911009 | 78 | |
bd86298e | 79 | actual_group = ext4_get_group_number(sb, block); |
68911009 | 80 | return (actual_group == block_group) ? 1 : 0; |
0bf7e837 JS |
81 | } |
82 | ||
d5b8f310 TT |
83 | /* Return the number of clusters used for file system metadata; this |
84 | * represents the overhead needed by the file system. | |
85 | */ | |
c197855e SH |
86 | static unsigned ext4_num_overhead_clusters(struct super_block *sb, |
87 | ext4_group_t block_group, | |
88 | struct ext4_group_desc *gdp) | |
0bf7e837 | 89 | { |
d5b8f310 TT |
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; | |
0bf7e837 | 94 | struct ext4_sb_info *sbi = EXT4_SB(sb); |
0bf7e837 | 95 | |
d5b8f310 TT |
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)) { | |
b0dd6b70 TT |
114 | block_cluster = EXT4_B2C(sbi, |
115 | ext4_block_bitmap(sb, gdp) - start); | |
d5b8f310 TT |
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, | |
b0dd6b70 | 126 | ext4_inode_bitmap(sb, gdp) - start); |
d5b8f310 TT |
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)) { | |
b0dd6b70 | 138 | c = EXT4_B2C(sbi, itbl_blk + i - start); |
d5b8f310 TT |
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; | |
0bf7e837 JS |
148 | } |
149 | } | |
d5b8f310 TT |
150 | |
151 | if (block_cluster != -1) | |
152 | num_clusters++; | |
153 | if (inode_cluster != -1) | |
154 | num_clusters++; | |
155 | ||
156 | return num_clusters; | |
0bf7e837 | 157 | } |
c2ea3fde | 158 | |
d5b8f310 TT |
159 | static unsigned int num_clusters_in_group(struct super_block *sb, |
160 | ext4_group_t block_group) | |
49f7f9af | 161 | { |
d5b8f310 TT |
162 | unsigned int blocks; |
163 | ||
49f7f9af TT |
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 | */ | |
d5b8f310 | 171 | blocks = ext4_blocks_count(EXT4_SB(sb)->s_es) - |
49f7f9af TT |
172 | ext4_group_first_block_no(sb, block_group); |
173 | } else | |
d5b8f310 TT |
174 | blocks = EXT4_BLOCKS_PER_GROUP(sb); |
175 | return EXT4_NUM_B2C(EXT4_SB(sb), blocks); | |
49f7f9af TT |
176 | } |
177 | ||
fd034a84 | 178 | /* Initializes an uninitialized block bitmap */ |
aef4885a | 179 | static int ext4_init_block_bitmap(struct super_block *sb, |
c197855e SH |
180 | struct buffer_head *bh, |
181 | ext4_group_t block_group, | |
182 | struct ext4_group_desc *gdp) | |
717d50e4 | 183 | { |
d5b8f310 | 184 | unsigned int bit, bit_max; |
717d50e4 | 185 | struct ext4_sb_info *sbi = EXT4_SB(sb); |
fd034a84 | 186 | ext4_fsblk_t start, tmp; |
bdfb6ff4 | 187 | struct ext4_group_info *grp; |
fd034a84 TT |
188 | |
189 | J_ASSERT_BH(bh, buffer_locked(bh)); | |
190 | ||
191 | /* If checksum is bad mark all blocks used to prevent allocation | |
192 | * essentially implementing a per-group read-only flag. */ | |
feb0ab32 | 193 | if (!ext4_group_desc_csum_verify(sb, block_group, gdp)) { |
bdfb6ff4 | 194 | grp = ext4_get_group_info(sb, block_group); |
e43bb4e6 NJ |
195 | if (!EXT4_MB_GRP_BBITMAP_CORRUPT(grp)) |
196 | percpu_counter_sub(&sbi->s_freeclusters_counter, | |
197 | grp->bb_free); | |
bdfb6ff4 | 198 | set_bit(EXT4_GROUP_INFO_BBITMAP_CORRUPT_BIT, &grp->bb_state); |
e43bb4e6 NJ |
199 | if (!EXT4_MB_GRP_IBITMAP_CORRUPT(grp)) { |
200 | int count; | |
201 | count = ext4_free_inodes_count(sb, gdp); | |
202 | percpu_counter_sub(&sbi->s_freeinodes_counter, | |
203 | count); | |
204 | } | |
bdfb6ff4 | 205 | set_bit(EXT4_GROUP_INFO_IBITMAP_CORRUPT_BIT, &grp->bb_state); |
6a797d27 | 206 | return -EFSBADCRC; |
717d50e4 | 207 | } |
fd034a84 | 208 | memset(bh->b_data, 0, sb->s_blocksize); |
717d50e4 | 209 | |
d5b8f310 | 210 | bit_max = ext4_num_base_meta_clusters(sb, block_group); |
5b9554dc TT |
211 | if ((bit_max >> 3) >= bh->b_size) |
212 | return -EFSCORRUPTED; | |
213 | ||
fd034a84 TT |
214 | for (bit = 0; bit < bit_max; bit++) |
215 | ext4_set_bit(bit, bh->b_data); | |
d00a6d7b | 216 | |
fd034a84 | 217 | start = ext4_group_first_block_no(sb, block_group); |
717d50e4 | 218 | |
fd034a84 TT |
219 | /* Set bits for block and inode bitmaps, and inode table */ |
220 | tmp = ext4_block_bitmap(sb, gdp); | |
ac48bb9b | 221 | if (ext4_block_in_group(sb, tmp, block_group)) |
d5b8f310 | 222 | ext4_set_bit(EXT4_B2C(sbi, tmp - start), bh->b_data); |
717d50e4 | 223 | |
fd034a84 | 224 | tmp = ext4_inode_bitmap(sb, gdp); |
ac48bb9b | 225 | if (ext4_block_in_group(sb, tmp, block_group)) |
d5b8f310 | 226 | ext4_set_bit(EXT4_B2C(sbi, tmp - start), bh->b_data); |
0bf7e837 | 227 | |
fd034a84 TT |
228 | tmp = ext4_inode_table(sb, gdp); |
229 | for (; tmp < ext4_inode_table(sb, gdp) + | |
230 | sbi->s_itb_per_group; tmp++) { | |
ac48bb9b | 231 | if (ext4_block_in_group(sb, tmp, block_group)) |
d5b8f310 | 232 | ext4_set_bit(EXT4_B2C(sbi, tmp - start), bh->b_data); |
717d50e4 | 233 | } |
d5b8f310 | 234 | |
fd034a84 TT |
235 | /* |
236 | * Also if the number of blocks within the group is less than | |
237 | * the blocksize * 8 ( which is the size of bitmap ), set rest | |
238 | * of the block bitmap to 1 | |
239 | */ | |
d5b8f310 | 240 | ext4_mark_bitmap_end(num_clusters_in_group(sb, block_group), |
fd034a84 | 241 | sb->s_blocksize * 8, bh->b_data); |
aef4885a | 242 | return 0; |
717d50e4 AD |
243 | } |
244 | ||
fd034a84 TT |
245 | /* Return the number of free blocks in a block group. It is used when |
246 | * the block bitmap is uninitialized, so we can't just count the bits | |
247 | * in the bitmap. */ | |
cff1dfd7 TT |
248 | unsigned ext4_free_clusters_after_init(struct super_block *sb, |
249 | ext4_group_t block_group, | |
250 | struct ext4_group_desc *gdp) | |
fd034a84 | 251 | { |
d5b8f310 TT |
252 | return num_clusters_in_group(sb, block_group) - |
253 | ext4_num_overhead_clusters(sb, block_group, gdp); | |
fd034a84 | 254 | } |
717d50e4 | 255 | |
ac27a0ec DK |
256 | /* |
257 | * The free blocks are managed by bitmaps. A file system contains several | |
258 | * blocks groups. Each group contains 1 bitmap block for blocks, 1 bitmap | |
259 | * block for inodes, N blocks for the inode table and data blocks. | |
260 | * | |
261 | * The file system contains group descriptors which are located after the | |
262 | * super block. Each descriptor contains the number of the bitmap block and | |
263 | * the free blocks count in the block. The descriptors are loaded in memory | |
e627432c | 264 | * when a file system is mounted (see ext4_fill_super). |
ac27a0ec DK |
265 | */ |
266 | ||
ac27a0ec | 267 | /** |
617ba13b | 268 | * ext4_get_group_desc() -- load group descriptor from disk |
ac27a0ec DK |
269 | * @sb: super block |
270 | * @block_group: given block group | |
271 | * @bh: pointer to the buffer head to store the block | |
272 | * group descriptor | |
273 | */ | |
af5bc92d | 274 | struct ext4_group_desc * ext4_get_group_desc(struct super_block *sb, |
fd2d4291 | 275 | ext4_group_t block_group, |
af5bc92d | 276 | struct buffer_head **bh) |
ac27a0ec | 277 | { |
498e5f24 TT |
278 | unsigned int group_desc; |
279 | unsigned int offset; | |
8df9675f | 280 | ext4_group_t ngroups = ext4_get_groups_count(sb); |
af5bc92d | 281 | struct ext4_group_desc *desc; |
617ba13b | 282 | struct ext4_sb_info *sbi = EXT4_SB(sb); |
ac27a0ec | 283 | |
8df9675f | 284 | if (block_group >= ngroups) { |
12062ddd ES |
285 | ext4_error(sb, "block_group >= groups_count - block_group = %u," |
286 | " groups_count = %u", block_group, ngroups); | |
ac27a0ec DK |
287 | |
288 | return NULL; | |
289 | } | |
ac27a0ec | 290 | |
617ba13b MC |
291 | group_desc = block_group >> EXT4_DESC_PER_BLOCK_BITS(sb); |
292 | offset = block_group & (EXT4_DESC_PER_BLOCK(sb) - 1); | |
ac27a0ec | 293 | if (!sbi->s_group_desc[group_desc]) { |
12062ddd | 294 | ext4_error(sb, "Group descriptor not loaded - " |
498e5f24 | 295 | "block_group = %u, group_desc = %u, desc = %u", |
af5bc92d | 296 | block_group, group_desc, offset); |
ac27a0ec DK |
297 | return NULL; |
298 | } | |
299 | ||
0d1ee42f AR |
300 | desc = (struct ext4_group_desc *)( |
301 | (__u8 *)sbi->s_group_desc[group_desc]->b_data + | |
302 | offset * EXT4_DESC_SIZE(sb)); | |
ac27a0ec DK |
303 | if (bh) |
304 | *bh = sbi->s_group_desc[group_desc]; | |
0d1ee42f | 305 | return desc; |
ac27a0ec DK |
306 | } |
307 | ||
7a4c5de2 TT |
308 | /* |
309 | * Return the block number which was discovered to be invalid, or 0 if | |
310 | * the block bitmap is valid. | |
311 | */ | |
312 | static ext4_fsblk_t ext4_valid_block_bitmap(struct super_block *sb, | |
313 | struct ext4_group_desc *desc, | |
dbde0abe | 314 | ext4_group_t block_group, |
7a4c5de2 | 315 | struct buffer_head *bh) |
abcb2947 | 316 | { |
e674e5cb | 317 | struct ext4_sb_info *sbi = EXT4_SB(sb); |
abcb2947 AK |
318 | ext4_grpblk_t offset; |
319 | ext4_grpblk_t next_zero_bit; | |
ae0db58d | 320 | ext4_grpblk_t max_bit = EXT4_CLUSTERS_PER_GROUP(sb); |
7a4c5de2 | 321 | ext4_fsblk_t blk; |
abcb2947 AK |
322 | ext4_fsblk_t group_first_block; |
323 | ||
e2b911c5 | 324 | if (ext4_has_feature_flex_bg(sb)) { |
abcb2947 AK |
325 | /* with FLEX_BG, the inode/block bitmaps and itable |
326 | * blocks may not be in the group at all | |
327 | * so the bitmap validation will be skipped for those groups | |
328 | * or it has to also read the block group where the bitmaps | |
329 | * are located to verify they are set. | |
330 | */ | |
7a4c5de2 | 331 | return 0; |
abcb2947 AK |
332 | } |
333 | group_first_block = ext4_group_first_block_no(sb, block_group); | |
334 | ||
335 | /* check whether block bitmap block number is set */ | |
7a4c5de2 TT |
336 | blk = ext4_block_bitmap(sb, desc); |
337 | offset = blk - group_first_block; | |
ae0db58d | 338 | if (offset < 0 || EXT4_B2C(sbi, offset) >= max_bit || |
b39430ea | 339 | !ext4_test_bit(EXT4_B2C(sbi, offset), bh->b_data)) |
abcb2947 | 340 | /* bad block bitmap */ |
7a4c5de2 | 341 | return blk; |
abcb2947 AK |
342 | |
343 | /* check whether the inode bitmap block number is set */ | |
7a4c5de2 TT |
344 | blk = ext4_inode_bitmap(sb, desc); |
345 | offset = blk - group_first_block; | |
ae0db58d | 346 | if (offset < 0 || EXT4_B2C(sbi, offset) >= max_bit || |
b39430ea | 347 | !ext4_test_bit(EXT4_B2C(sbi, offset), bh->b_data)) |
abcb2947 | 348 | /* bad block bitmap */ |
7a4c5de2 | 349 | return blk; |
abcb2947 AK |
350 | |
351 | /* check whether the inode table block number is set */ | |
7a4c5de2 TT |
352 | blk = ext4_inode_table(sb, desc); |
353 | offset = blk - group_first_block; | |
ae0db58d LC |
354 | if (offset < 0 || EXT4_B2C(sbi, offset) >= max_bit || |
355 | EXT4_B2C(sbi, offset + sbi->s_itb_per_group) >= max_bit) | |
b39430ea | 356 | return blk; |
abcb2947 | 357 | next_zero_bit = ext4_find_next_zero_bit(bh->b_data, |
e674e5cb DW |
358 | EXT4_B2C(sbi, offset + EXT4_SB(sb)->s_itb_per_group), |
359 | EXT4_B2C(sbi, offset)); | |
360 | if (next_zero_bit < | |
361 | EXT4_B2C(sbi, offset + EXT4_SB(sb)->s_itb_per_group)) | |
7a4c5de2 TT |
362 | /* bad bitmap for inode tables */ |
363 | return blk; | |
abcb2947 AK |
364 | return 0; |
365 | } | |
fa77dcfa | 366 | |
9008a58e DW |
367 | static int ext4_validate_block_bitmap(struct super_block *sb, |
368 | struct ext4_group_desc *desc, | |
369 | ext4_group_t block_group, | |
370 | struct buffer_head *bh) | |
fa77dcfa | 371 | { |
7a4c5de2 | 372 | ext4_fsblk_t blk; |
163a203d | 373 | struct ext4_group_info *grp = ext4_get_group_info(sb, block_group); |
e43bb4e6 | 374 | struct ext4_sb_info *sbi = EXT4_SB(sb); |
7a4c5de2 | 375 | |
9008a58e DW |
376 | if (buffer_verified(bh)) |
377 | return 0; | |
378 | if (EXT4_MB_GRP_BBITMAP_CORRUPT(grp)) | |
379 | return -EFSCORRUPTED; | |
fa77dcfa DW |
380 | |
381 | ext4_lock_group(sb, block_group); | |
dc1b4b71 TT |
382 | if (buffer_verified(bh)) |
383 | goto verified; | |
9008a58e DW |
384 | if (unlikely(!ext4_block_bitmap_csum_verify(sb, block_group, |
385 | desc, bh))) { | |
7a4c5de2 | 386 | ext4_unlock_group(sb, block_group); |
9008a58e | 387 | ext4_error(sb, "bg %u: bad block bitmap checksum", block_group); |
e43bb4e6 NJ |
388 | if (!EXT4_MB_GRP_BBITMAP_CORRUPT(grp)) |
389 | percpu_counter_sub(&sbi->s_freeclusters_counter, | |
390 | grp->bb_free); | |
163a203d | 391 | set_bit(EXT4_GROUP_INFO_BBITMAP_CORRUPT_BIT, &grp->bb_state); |
9008a58e | 392 | return -EFSBADCRC; |
7a4c5de2 | 393 | } |
9008a58e DW |
394 | blk = ext4_valid_block_bitmap(sb, desc, block_group, bh); |
395 | if (unlikely(blk != 0)) { | |
7a4c5de2 | 396 | ext4_unlock_group(sb, block_group); |
9008a58e DW |
397 | ext4_error(sb, "bg %u: block %llu: invalid block bitmap", |
398 | block_group, blk); | |
e43bb4e6 NJ |
399 | if (!EXT4_MB_GRP_BBITMAP_CORRUPT(grp)) |
400 | percpu_counter_sub(&sbi->s_freeclusters_counter, | |
401 | grp->bb_free); | |
163a203d | 402 | set_bit(EXT4_GROUP_INFO_BBITMAP_CORRUPT_BIT, &grp->bb_state); |
9008a58e | 403 | return -EFSCORRUPTED; |
7a4c5de2 TT |
404 | } |
405 | set_buffer_verified(bh); | |
dc1b4b71 | 406 | verified: |
fa77dcfa | 407 | ext4_unlock_group(sb, block_group); |
9008a58e | 408 | return 0; |
fa77dcfa DW |
409 | } |
410 | ||
ac27a0ec | 411 | /** |
15b49132 | 412 | * ext4_read_block_bitmap_nowait() |
ac27a0ec DK |
413 | * @sb: super block |
414 | * @block_group: given block group | |
415 | * | |
abcb2947 AK |
416 | * Read the bitmap for a given block_group,and validate the |
417 | * bits for block/inode/inode tables are set in the bitmaps | |
ac27a0ec DK |
418 | * |
419 | * Return buffer_head on success or NULL in case of failure. | |
420 | */ | |
717d50e4 | 421 | struct buffer_head * |
813e5727 | 422 | ext4_read_block_bitmap_nowait(struct super_block *sb, ext4_group_t block_group) |
ac27a0ec | 423 | { |
af5bc92d | 424 | struct ext4_group_desc *desc; |
b39430ea | 425 | struct ext4_sb_info *sbi = EXT4_SB(sb); |
813e5727 | 426 | struct buffer_head *bh; |
7c9e69fa | 427 | ext4_fsblk_t bitmap_blk; |
9008a58e | 428 | int err; |
ac27a0ec | 429 | |
717d50e4 | 430 | desc = ext4_get_group_desc(sb, block_group, NULL); |
ac27a0ec | 431 | if (!desc) |
9008a58e | 432 | return ERR_PTR(-EFSCORRUPTED); |
7c9e69fa | 433 | bitmap_blk = ext4_block_bitmap(sb, desc); |
b39430ea TT |
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 | return ERR_PTR(-EFSCORRUPTED); | |
439 | } | |
abcb2947 AK |
440 | bh = sb_getblk(sb, bitmap_blk); |
441 | if (unlikely(!bh)) { | |
813e5727 TT |
442 | ext4_error(sb, "Cannot get buffer for block bitmap - " |
443 | "block_group = %u, block_bitmap = %llu", | |
444 | block_group, bitmap_blk); | |
9008a58e | 445 | return ERR_PTR(-ENOMEM); |
abcb2947 | 446 | } |
2ccb5fb9 AK |
447 | |
448 | if (bitmap_uptodate(bh)) | |
fa77dcfa | 449 | goto verify; |
abcb2947 | 450 | |
c806e68f | 451 | lock_buffer(bh); |
2ccb5fb9 AK |
452 | if (bitmap_uptodate(bh)) { |
453 | unlock_buffer(bh); | |
fa77dcfa | 454 | goto verify; |
2ccb5fb9 | 455 | } |
955ce5f5 | 456 | ext4_lock_group(sb, block_group); |
44a4bc97 TT |
457 | if (ext4_has_group_desc_csum(sb) && |
458 | (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT))) { | |
459 | if (block_group == 0) { | |
460 | ext4_unlock_group(sb, block_group); | |
461 | unlock_buffer(bh); | |
462 | ext4_error(sb, "Block bitmap for bg 0 marked " | |
463 | "uninitialized"); | |
464 | err = -EFSCORRUPTED; | |
465 | goto out; | |
466 | } | |
aef4885a | 467 | err = ext4_init_block_bitmap(sb, bh, block_group, desc); |
2ccb5fb9 | 468 | set_bitmap_uptodate(bh); |
abcb2947 | 469 | set_buffer_uptodate(bh); |
bd499f55 | 470 | set_buffer_verified(bh); |
955ce5f5 | 471 | ext4_unlock_group(sb, block_group); |
3300beda | 472 | unlock_buffer(bh); |
05145bd7 JK |
473 | if (err) { |
474 | ext4_error(sb, "Failed to init block bitmap for group " | |
475 | "%u: %d", block_group, err); | |
9008a58e | 476 | goto out; |
05145bd7 | 477 | } |
41e5b7ed | 478 | goto verify; |
717d50e4 | 479 | } |
955ce5f5 | 480 | ext4_unlock_group(sb, block_group); |
2ccb5fb9 AK |
481 | if (buffer_uptodate(bh)) { |
482 | /* | |
483 | * if not uninit if bh is uptodate, | |
484 | * bitmap is also uptodate | |
485 | */ | |
486 | set_bitmap_uptodate(bh); | |
487 | unlock_buffer(bh); | |
fa77dcfa | 488 | goto verify; |
2ccb5fb9 AK |
489 | } |
490 | /* | |
813e5727 | 491 | * submit the buffer_head for reading |
2ccb5fb9 | 492 | */ |
813e5727 | 493 | set_buffer_new(bh); |
0562e0ba | 494 | trace_ext4_read_block_bitmap_load(sb, block_group); |
813e5727 TT |
495 | bh->b_end_io = ext4_end_bitmap_read; |
496 | get_bh(bh); | |
2a222ca9 | 497 | submit_bh(REQ_OP_READ, REQ_META | REQ_PRIO, bh); |
813e5727 | 498 | return bh; |
fa77dcfa | 499 | verify: |
9008a58e DW |
500 | err = ext4_validate_block_bitmap(sb, desc, block_group, bh); |
501 | if (err) | |
502 | goto out; | |
503 | return bh; | |
504 | out: | |
48d9eb97 | 505 | put_bh(bh); |
9008a58e | 506 | return ERR_PTR(err); |
813e5727 TT |
507 | } |
508 | ||
509 | /* Returns 0 on success, 1 on error */ | |
510 | int ext4_wait_block_bitmap(struct super_block *sb, ext4_group_t block_group, | |
511 | struct buffer_head *bh) | |
512 | { | |
513 | struct ext4_group_desc *desc; | |
514 | ||
515 | if (!buffer_new(bh)) | |
516 | return 0; | |
517 | desc = ext4_get_group_desc(sb, block_group, NULL); | |
518 | if (!desc) | |
9008a58e | 519 | return -EFSCORRUPTED; |
813e5727 TT |
520 | wait_on_buffer(bh); |
521 | if (!buffer_uptodate(bh)) { | |
12062ddd | 522 | ext4_error(sb, "Cannot read block bitmap - " |
813e5727 | 523 | "block_group = %u, block_bitmap = %llu", |
d4dc462f | 524 | block_group, (unsigned long long) bh->b_blocknr); |
9008a58e | 525 | return -EIO; |
abcb2947 | 526 | } |
813e5727 TT |
527 | clear_buffer_new(bh); |
528 | /* Panic or remount fs read-only if block bitmap is invalid */ | |
9008a58e | 529 | return ext4_validate_block_bitmap(sb, desc, block_group, bh); |
813e5727 TT |
530 | } |
531 | ||
532 | struct buffer_head * | |
533 | ext4_read_block_bitmap(struct super_block *sb, ext4_group_t block_group) | |
534 | { | |
535 | struct buffer_head *bh; | |
9008a58e | 536 | int err; |
813e5727 TT |
537 | |
538 | bh = ext4_read_block_bitmap_nowait(sb, block_group); | |
9008a58e DW |
539 | if (IS_ERR(bh)) |
540 | return bh; | |
541 | err = ext4_wait_block_bitmap(sb, block_group, bh); | |
542 | if (err) { | |
813e5727 | 543 | put_bh(bh); |
9008a58e | 544 | return ERR_PTR(err); |
813e5727 | 545 | } |
ac27a0ec DK |
546 | return bh; |
547 | } | |
ac27a0ec | 548 | |
8c3bf8a0 | 549 | /** |
df55c99d | 550 | * ext4_has_free_clusters() |
8c3bf8a0 | 551 | * @sbi: in-core super block structure. |
df55c99d TT |
552 | * @nclusters: number of needed blocks |
553 | * @flags: flags from ext4_mb_new_blocks() | |
8c3bf8a0 | 554 | * |
df55c99d | 555 | * Check if filesystem has nclusters free & available for allocation. |
8c3bf8a0 ES |
556 | * On success return 1, return 0 on failure. |
557 | */ | |
df55c99d TT |
558 | static int ext4_has_free_clusters(struct ext4_sb_info *sbi, |
559 | s64 nclusters, unsigned int flags) | |
a30d542a | 560 | { |
27dd4385 | 561 | s64 free_clusters, dirty_clusters, rsv, resv_clusters; |
57042651 | 562 | struct percpu_counter *fcc = &sbi->s_freeclusters_counter; |
df55c99d | 563 | struct percpu_counter *dcc = &sbi->s_dirtyclusters_counter; |
a30d542a | 564 | |
df55c99d TT |
565 | free_clusters = percpu_counter_read_positive(fcc); |
566 | dirty_clusters = percpu_counter_read_positive(dcc); | |
27dd4385 | 567 | resv_clusters = atomic64_read(&sbi->s_resv_clusters); |
304e220f LC |
568 | |
569 | /* | |
570 | * r_blocks_count should always be multiple of the cluster ratio so | |
571 | * we are safe to do a plane bit shift only. | |
572 | */ | |
27dd4385 LC |
573 | rsv = (ext4_r_blocks_count(sbi->s_es) >> sbi->s_cluster_bits) + |
574 | resv_clusters; | |
a30d542a | 575 | |
27dd4385 | 576 | if (free_clusters - (nclusters + rsv + dirty_clusters) < |
df55c99d | 577 | EXT4_FREECLUSTERS_WATERMARK) { |
304e220f | 578 | free_clusters = percpu_counter_sum_positive(fcc); |
df55c99d | 579 | dirty_clusters = percpu_counter_sum_positive(dcc); |
6bc6e63f | 580 | } |
df55c99d TT |
581 | /* Check whether we have space after accounting for current |
582 | * dirty clusters & root reserved clusters. | |
6bc6e63f | 583 | */ |
27dd4385 | 584 | if (free_clusters >= (rsv + nclusters + dirty_clusters)) |
a996031c | 585 | return 1; |
a30d542a | 586 | |
df55c99d | 587 | /* Hm, nope. Are (enough) root reserved clusters available? */ |
08cefc7a EB |
588 | if (uid_eq(sbi->s_resuid, current_fsuid()) || |
589 | (!gid_eq(sbi->s_resgid, GLOBAL_ROOT_GID) && in_group_p(sbi->s_resgid)) || | |
55f020db | 590 | capable(CAP_SYS_RESOURCE) || |
27dd4385 | 591 | (flags & EXT4_MB_USE_ROOT_BLOCKS)) { |
55f020db | 592 | |
27dd4385 LC |
593 | if (free_clusters >= (nclusters + dirty_clusters + |
594 | resv_clusters)) | |
595 | return 1; | |
596 | } | |
597 | /* No free blocks. Let's see if we can dip into reserved pool */ | |
598 | if (flags & EXT4_MB_USE_RESERVED) { | |
df55c99d | 599 | if (free_clusters >= (nclusters + dirty_clusters)) |
a996031c ES |
600 | return 1; |
601 | } | |
602 | ||
603 | return 0; | |
a30d542a AK |
604 | } |
605 | ||
e7d5f315 TT |
606 | int ext4_claim_free_clusters(struct ext4_sb_info *sbi, |
607 | s64 nclusters, unsigned int flags) | |
ac27a0ec | 608 | { |
df55c99d | 609 | if (ext4_has_free_clusters(sbi, nclusters, flags)) { |
e7d5f315 | 610 | percpu_counter_add(&sbi->s_dirtyclusters_counter, nclusters); |
16eb7295 | 611 | return 0; |
8c3bf8a0 ES |
612 | } else |
613 | return -ENOSPC; | |
a30d542a | 614 | } |
07031431 | 615 | |
ac27a0ec | 616 | /** |
617ba13b | 617 | * ext4_should_retry_alloc() |
ac27a0ec DK |
618 | * @sb: super block |
619 | * @retries number of attemps has been made | |
620 | * | |
617ba13b | 621 | * ext4_should_retry_alloc() is called when ENOSPC is returned, and if |
ac27a0ec | 622 | * it is profitable to retry the operation, this function will wait |
25985edc | 623 | * for the current or committing transaction to complete, and then |
ac27a0ec DK |
624 | * return TRUE. |
625 | * | |
626 | * if the total number of retries exceed three times, return FALSE. | |
627 | */ | |
617ba13b | 628 | int ext4_should_retry_alloc(struct super_block *sb, int *retries) |
ac27a0ec | 629 | { |
df55c99d | 630 | if (!ext4_has_free_clusters(EXT4_SB(sb), 1, 0) || |
8f64b32e ES |
631 | (*retries)++ > 3 || |
632 | !EXT4_SB(sb)->s_journal) | |
ac27a0ec DK |
633 | return 0; |
634 | ||
635 | jbd_debug(1, "%s: retrying operation after ENOSPC\n", sb->s_id); | |
636 | ||
d08854f5 TT |
637 | smp_mb(); |
638 | if (EXT4_SB(sb)->s_mb_free_pending) | |
639 | jbd2_journal_force_commit_nested(EXT4_SB(sb)->s_journal); | |
dbc427ce | 640 | return 1; |
ac27a0ec DK |
641 | } |
642 | ||
654b4908 | 643 | /* |
d2a17637 | 644 | * ext4_new_meta_blocks() -- allocate block for meta data (indexing) blocks |
654b4908 AK |
645 | * |
646 | * @handle: handle to this transaction | |
647 | * @inode: file inode | |
648 | * @goal: given target block(filesystem wide) | |
7b415bf6 | 649 | * @count: pointer to total number of clusters needed |
654b4908 AK |
650 | * @errp: error code |
651 | * | |
97df5d15 | 652 | * Return 1st allocated block number on success, *count stores total account |
d2a17637 | 653 | * error stores in errp pointer |
654b4908 | 654 | */ |
d2a17637 | 655 | ext4_fsblk_t ext4_new_meta_blocks(handle_t *handle, struct inode *inode, |
55f020db AH |
656 | ext4_fsblk_t goal, unsigned int flags, |
657 | unsigned long *count, int *errp) | |
654b4908 | 658 | { |
97df5d15 | 659 | struct ext4_allocation_request ar; |
d2a17637 | 660 | ext4_fsblk_t ret; |
97df5d15 TT |
661 | |
662 | memset(&ar, 0, sizeof(ar)); | |
663 | /* Fill with neighbour allocated blocks */ | |
664 | ar.inode = inode; | |
665 | ar.goal = goal; | |
666 | ar.len = count ? *count : 1; | |
55f020db | 667 | ar.flags = flags; |
97df5d15 TT |
668 | |
669 | ret = ext4_mb_new_blocks(handle, &ar, errp); | |
670 | if (count) | |
671 | *count = ar.len; | |
d2a17637 | 672 | /* |
72b8ab9d ES |
673 | * Account for the allocated meta blocks. We will never |
674 | * fail EDQUOT for metdata, but we do account for it. | |
d2a17637 | 675 | */ |
e3cf5d5d | 676 | if (!(*errp) && (flags & EXT4_MB_DELALLOC_RESERVED)) { |
7b415bf6 AK |
677 | dquot_alloc_block_nofail(inode, |
678 | EXT4_C2B(EXT4_SB(inode->i_sb), ar.len)); | |
d2a17637 MC |
679 | } |
680 | return ret; | |
654b4908 AK |
681 | } |
682 | ||
ac27a0ec | 683 | /** |
5dee5437 | 684 | * ext4_count_free_clusters() -- count filesystem free clusters |
ac27a0ec DK |
685 | * @sb: superblock |
686 | * | |
5dee5437 | 687 | * Adds up the number of free clusters from each block group. |
ac27a0ec | 688 | */ |
5dee5437 | 689 | ext4_fsblk_t ext4_count_free_clusters(struct super_block *sb) |
ac27a0ec | 690 | { |
617ba13b MC |
691 | ext4_fsblk_t desc_count; |
692 | struct ext4_group_desc *gdp; | |
fd2d4291 | 693 | ext4_group_t i; |
8df9675f | 694 | ext4_group_t ngroups = ext4_get_groups_count(sb); |
2746f7a1 | 695 | struct ext4_group_info *grp; |
617ba13b MC |
696 | #ifdef EXT4FS_DEBUG |
697 | struct ext4_super_block *es; | |
698 | ext4_fsblk_t bitmap_count; | |
498e5f24 | 699 | unsigned int x; |
ac27a0ec DK |
700 | struct buffer_head *bitmap_bh = NULL; |
701 | ||
617ba13b | 702 | es = EXT4_SB(sb)->s_es; |
ac27a0ec DK |
703 | desc_count = 0; |
704 | bitmap_count = 0; | |
705 | gdp = NULL; | |
706 | ||
ac27a0ec | 707 | for (i = 0; i < ngroups; i++) { |
617ba13b | 708 | gdp = ext4_get_group_desc(sb, i, NULL); |
ac27a0ec DK |
709 | if (!gdp) |
710 | continue; | |
2746f7a1 DW |
711 | grp = NULL; |
712 | if (EXT4_SB(sb)->s_group_info) | |
713 | grp = ext4_get_group_info(sb, i); | |
714 | if (!grp || !EXT4_MB_GRP_BBITMAP_CORRUPT(grp)) | |
715 | desc_count += ext4_free_group_clusters(sb, gdp); | |
ac27a0ec | 716 | brelse(bitmap_bh); |
574ca174 | 717 | bitmap_bh = ext4_read_block_bitmap(sb, i); |
9008a58e DW |
718 | if (IS_ERR(bitmap_bh)) { |
719 | bitmap_bh = NULL; | |
ac27a0ec | 720 | continue; |
9008a58e | 721 | } |
ac27a0ec | 722 | |
f6fb99ca | 723 | x = ext4_count_free(bitmap_bh->b_data, |
036acea2 | 724 | EXT4_CLUSTERS_PER_GROUP(sb) / 8); |
9fd9784c | 725 | printk(KERN_DEBUG "group %u: stored = %d, counted = %u\n", |
021b65bb | 726 | i, ext4_free_group_clusters(sb, gdp), x); |
ac27a0ec DK |
727 | bitmap_count += x; |
728 | } | |
729 | brelse(bitmap_bh); | |
5dee5437 TT |
730 | printk(KERN_DEBUG "ext4_count_free_clusters: stored = %llu" |
731 | ", computed = %llu, %llu\n", | |
810da240 | 732 | EXT4_NUM_B2C(EXT4_SB(sb), ext4_free_blocks_count(es)), |
4776004f | 733 | desc_count, bitmap_count); |
ac27a0ec DK |
734 | return bitmap_count; |
735 | #else | |
736 | desc_count = 0; | |
ac27a0ec | 737 | for (i = 0; i < ngroups; i++) { |
617ba13b | 738 | gdp = ext4_get_group_desc(sb, i, NULL); |
ac27a0ec DK |
739 | if (!gdp) |
740 | continue; | |
2746f7a1 DW |
741 | grp = NULL; |
742 | if (EXT4_SB(sb)->s_group_info) | |
743 | grp = ext4_get_group_info(sb, i); | |
744 | if (!grp || !EXT4_MB_GRP_BBITMAP_CORRUPT(grp)) | |
745 | desc_count += ext4_free_group_clusters(sb, gdp); | |
ac27a0ec DK |
746 | } |
747 | ||
748 | return desc_count; | |
749 | #endif | |
750 | } | |
751 | ||
fd2d4291 | 752 | static inline int test_root(ext4_group_t a, int b) |
ac27a0ec | 753 | { |
f4afb4f4 TT |
754 | while (1) { |
755 | if (a < b) | |
756 | return 0; | |
757 | if (a == b) | |
758 | return 1; | |
759 | if ((a % b) != 0) | |
760 | return 0; | |
761 | a = a / b; | |
762 | } | |
ac27a0ec DK |
763 | } |
764 | ||
ac27a0ec | 765 | /** |
617ba13b | 766 | * ext4_bg_has_super - number of blocks used by the superblock in group |
ac27a0ec DK |
767 | * @sb: superblock for filesystem |
768 | * @group: group number to check | |
769 | * | |
770 | * Return the number of blocks used by the superblock (primary or backup) | |
771 | * in this group. Currently this will be only 0 or 1. | |
772 | */ | |
fd2d4291 | 773 | int ext4_bg_has_super(struct super_block *sb, ext4_group_t group) |
ac27a0ec | 774 | { |
1beeef1b DW |
775 | struct ext4_super_block *es = EXT4_SB(sb)->s_es; |
776 | ||
777 | if (group == 0) | |
778 | return 1; | |
e2b911c5 | 779 | if (ext4_has_feature_sparse_super2(sb)) { |
1beeef1b DW |
780 | if (group == le32_to_cpu(es->s_backup_bgs[0]) || |
781 | group == le32_to_cpu(es->s_backup_bgs[1])) | |
782 | return 1; | |
783 | return 0; | |
784 | } | |
e2b911c5 | 785 | if ((group <= 1) || !ext4_has_feature_sparse_super(sb)) |
1beeef1b DW |
786 | return 1; |
787 | if (!(group & 1)) | |
ac27a0ec | 788 | return 0; |
1beeef1b DW |
789 | if (test_root(group, 3) || (test_root(group, 5)) || |
790 | test_root(group, 7)) | |
791 | return 1; | |
792 | ||
793 | return 0; | |
ac27a0ec DK |
794 | } |
795 | ||
fd2d4291 AM |
796 | static unsigned long ext4_bg_num_gdb_meta(struct super_block *sb, |
797 | ext4_group_t group) | |
ac27a0ec | 798 | { |
617ba13b | 799 | unsigned long metagroup = group / EXT4_DESC_PER_BLOCK(sb); |
fd2d4291 AM |
800 | ext4_group_t first = metagroup * EXT4_DESC_PER_BLOCK(sb); |
801 | ext4_group_t last = first + EXT4_DESC_PER_BLOCK(sb) - 1; | |
ac27a0ec DK |
802 | |
803 | if (group == first || group == first + 1 || group == last) | |
804 | return 1; | |
805 | return 0; | |
806 | } | |
807 | ||
fd2d4291 AM |
808 | static unsigned long ext4_bg_num_gdb_nometa(struct super_block *sb, |
809 | ext4_group_t group) | |
ac27a0ec | 810 | { |
8dadb198 TT |
811 | if (!ext4_bg_has_super(sb, group)) |
812 | return 0; | |
813 | ||
e2b911c5 | 814 | if (ext4_has_feature_meta_bg(sb)) |
8dadb198 TT |
815 | return le32_to_cpu(EXT4_SB(sb)->s_es->s_first_meta_bg); |
816 | else | |
817 | return EXT4_SB(sb)->s_gdb_count; | |
ac27a0ec DK |
818 | } |
819 | ||
820 | /** | |
617ba13b | 821 | * ext4_bg_num_gdb - number of blocks used by the group table in group |
ac27a0ec DK |
822 | * @sb: superblock for filesystem |
823 | * @group: group number to check | |
824 | * | |
825 | * Return the number of blocks used by the group descriptor table | |
826 | * (primary or backup) in this group. In the future there may be a | |
827 | * different number of descriptor blocks in each group. | |
828 | */ | |
fd2d4291 | 829 | unsigned long ext4_bg_num_gdb(struct super_block *sb, ext4_group_t group) |
ac27a0ec DK |
830 | { |
831 | unsigned long first_meta_bg = | |
617ba13b MC |
832 | le32_to_cpu(EXT4_SB(sb)->s_es->s_first_meta_bg); |
833 | unsigned long metagroup = group / EXT4_DESC_PER_BLOCK(sb); | |
ac27a0ec | 834 | |
e2b911c5 | 835 | if (!ext4_has_feature_meta_bg(sb) || metagroup < first_meta_bg) |
af5bc92d | 836 | return ext4_bg_num_gdb_nometa(sb, group); |
ac27a0ec | 837 | |
617ba13b | 838 | return ext4_bg_num_gdb_meta(sb,group); |
ac27a0ec DK |
839 | |
840 | } | |
c2ea3fde | 841 | |
49f7f9af | 842 | /* |
d5b8f310 | 843 | * This function returns the number of file system metadata clusters at |
49f7f9af TT |
844 | * the beginning of a block group, including the reserved gdt blocks. |
845 | */ | |
5f163cc7 | 846 | static unsigned ext4_num_base_meta_clusters(struct super_block *sb, |
d5b8f310 | 847 | ext4_group_t block_group) |
49f7f9af TT |
848 | { |
849 | struct ext4_sb_info *sbi = EXT4_SB(sb); | |
d5b8f310 | 850 | unsigned num; |
49f7f9af TT |
851 | |
852 | /* Check for superblock and gdt backups in this group */ | |
853 | num = ext4_bg_has_super(sb, block_group); | |
854 | ||
e2b911c5 | 855 | if (!ext4_has_feature_meta_bg(sb) || |
49f7f9af TT |
856 | block_group < le32_to_cpu(sbi->s_es->s_first_meta_bg) * |
857 | sbi->s_desc_per_block) { | |
858 | if (num) { | |
859 | num += ext4_bg_num_gdb(sb, block_group); | |
860 | num += le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks); | |
861 | } | |
862 | } else { /* For META_BG_BLOCK_GROUPS */ | |
863 | num += ext4_bg_num_gdb(sb, block_group); | |
864 | } | |
d5b8f310 | 865 | return EXT4_NUM_B2C(sbi, num); |
49f7f9af | 866 | } |
f86186b4 ES |
867 | /** |
868 | * ext4_inode_to_goal_block - return a hint for block allocation | |
869 | * @inode: inode for block allocation | |
870 | * | |
871 | * Return the ideal location to start allocating blocks for a | |
872 | * newly created inode. | |
873 | */ | |
874 | ext4_fsblk_t ext4_inode_to_goal_block(struct inode *inode) | |
875 | { | |
876 | struct ext4_inode_info *ei = EXT4_I(inode); | |
877 | ext4_group_t block_group; | |
878 | ext4_grpblk_t colour; | |
879 | int flex_size = ext4_flex_bg_size(EXT4_SB(inode->i_sb)); | |
880 | ext4_fsblk_t bg_start; | |
881 | ext4_fsblk_t last_block; | |
882 | ||
883 | block_group = ei->i_block_group; | |
884 | if (flex_size >= EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME) { | |
885 | /* | |
886 | * If there are at least EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME | |
887 | * block groups per flexgroup, reserve the first block | |
888 | * group for directories and special files. Regular | |
889 | * files will start at the second block group. This | |
890 | * tends to speed up directory access and improves | |
891 | * fsck times. | |
892 | */ | |
893 | block_group &= ~(flex_size-1); | |
894 | if (S_ISREG(inode->i_mode)) | |
895 | block_group++; | |
896 | } | |
897 | bg_start = ext4_group_first_block_no(inode->i_sb, block_group); | |
898 | last_block = ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es) - 1; | |
899 | ||
900 | /* | |
901 | * If we are doing delayed allocation, we don't need take | |
902 | * colour into account. | |
903 | */ | |
904 | if (test_opt(inode->i_sb, DELALLOC)) | |
905 | return bg_start; | |
906 | ||
907 | if (bg_start + EXT4_BLOCKS_PER_GROUP(inode->i_sb) <= last_block) | |
908 | colour = (current->pid % 16) * | |
909 | (EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16); | |
910 | else | |
911 | colour = (current->pid % 16) * ((last_block - bg_start) / 16); | |
912 | return bg_start + colour; | |
913 | } | |
914 |