Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * linux/fs/ext2/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 | ||
1da177e4 LT |
14 | #include "ext2.h" |
15 | #include <linux/quotaops.h> | |
16 | #include <linux/sched.h> | |
17 | #include <linux/buffer_head.h> | |
16f7e0fe | 18 | #include <linux/capability.h> |
1da177e4 LT |
19 | |
20 | /* | |
21 | * balloc.c contains the blocks allocation and deallocation routines | |
22 | */ | |
23 | ||
24 | /* | |
25 | * The free blocks are managed by bitmaps. A file system contains several | |
26 | * blocks groups. Each group contains 1 bitmap block for blocks, 1 bitmap | |
27 | * block for inodes, N blocks for the inode table and data blocks. | |
28 | * | |
29 | * The file system contains group descriptors which are located after the | |
30 | * super block. Each descriptor contains the number of the bitmap block and | |
31 | * the free blocks count in the block. The descriptors are loaded in memory | |
32 | * when a file system is mounted (see ext2_read_super). | |
33 | */ | |
34 | ||
35 | ||
36 | #define in_range(b, first, len) ((b) >= (first) && (b) <= (first) + (len) - 1) | |
37 | ||
38 | struct ext2_group_desc * ext2_get_group_desc(struct super_block * sb, | |
39 | unsigned int block_group, | |
40 | struct buffer_head ** bh) | |
41 | { | |
42 | unsigned long group_desc; | |
43 | unsigned long offset; | |
44 | struct ext2_group_desc * desc; | |
45 | struct ext2_sb_info *sbi = EXT2_SB(sb); | |
46 | ||
47 | if (block_group >= sbi->s_groups_count) { | |
48 | ext2_error (sb, "ext2_get_group_desc", | |
49 | "block_group >= groups_count - " | |
50 | "block_group = %d, groups_count = %lu", | |
51 | block_group, sbi->s_groups_count); | |
52 | ||
53 | return NULL; | |
54 | } | |
55 | ||
56 | group_desc = block_group >> EXT2_DESC_PER_BLOCK_BITS(sb); | |
57 | offset = block_group & (EXT2_DESC_PER_BLOCK(sb) - 1); | |
58 | if (!sbi->s_group_desc[group_desc]) { | |
59 | ext2_error (sb, "ext2_get_group_desc", | |
60 | "Group descriptor not loaded - " | |
61 | "block_group = %d, group_desc = %lu, desc = %lu", | |
62 | block_group, group_desc, offset); | |
63 | return NULL; | |
64 | } | |
65 | ||
66 | desc = (struct ext2_group_desc *) sbi->s_group_desc[group_desc]->b_data; | |
67 | if (bh) | |
68 | *bh = sbi->s_group_desc[group_desc]; | |
69 | return desc + offset; | |
70 | } | |
71 | ||
72 | /* | |
73 | * Read the bitmap for a given block_group, reading into the specified | |
74 | * slot in the superblock's bitmap cache. | |
75 | * | |
76 | * Return buffer_head on success or NULL in case of failure. | |
77 | */ | |
78 | static struct buffer_head * | |
79 | read_block_bitmap(struct super_block *sb, unsigned int block_group) | |
80 | { | |
81 | struct ext2_group_desc * desc; | |
82 | struct buffer_head * bh = NULL; | |
83 | ||
84 | desc = ext2_get_group_desc (sb, block_group, NULL); | |
85 | if (!desc) | |
86 | goto error_out; | |
87 | bh = sb_bread(sb, le32_to_cpu(desc->bg_block_bitmap)); | |
88 | if (!bh) | |
89 | ext2_error (sb, "read_block_bitmap", | |
90 | "Cannot read block bitmap - " | |
91 | "block_group = %d, block_bitmap = %u", | |
92 | block_group, le32_to_cpu(desc->bg_block_bitmap)); | |
93 | error_out: | |
94 | return bh; | |
95 | } | |
96 | ||
97 | /* | |
98 | * Set sb->s_dirt here because the superblock was "logically" altered. We | |
99 | * need to recalculate its free blocks count and flush it out. | |
100 | */ | |
101 | static int reserve_blocks(struct super_block *sb, int count) | |
102 | { | |
103 | struct ext2_sb_info *sbi = EXT2_SB(sb); | |
104 | struct ext2_super_block *es = sbi->s_es; | |
105 | unsigned free_blocks; | |
106 | unsigned root_blocks; | |
107 | ||
108 | free_blocks = percpu_counter_read_positive(&sbi->s_freeblocks_counter); | |
109 | root_blocks = le32_to_cpu(es->s_r_blocks_count); | |
110 | ||
111 | if (free_blocks < count) | |
112 | count = free_blocks; | |
113 | ||
114 | if (free_blocks < root_blocks + count && !capable(CAP_SYS_RESOURCE) && | |
115 | sbi->s_resuid != current->fsuid && | |
116 | (sbi->s_resgid == 0 || !in_group_p (sbi->s_resgid))) { | |
117 | /* | |
118 | * We are too close to reserve and we are not privileged. | |
119 | * Can we allocate anything at all? | |
120 | */ | |
121 | if (free_blocks > root_blocks) | |
122 | count = free_blocks - root_blocks; | |
123 | else | |
124 | return 0; | |
125 | } | |
126 | ||
127 | percpu_counter_mod(&sbi->s_freeblocks_counter, -count); | |
128 | sb->s_dirt = 1; | |
129 | return count; | |
130 | } | |
131 | ||
132 | static void release_blocks(struct super_block *sb, int count) | |
133 | { | |
134 | if (count) { | |
135 | struct ext2_sb_info *sbi = EXT2_SB(sb); | |
136 | ||
137 | percpu_counter_mod(&sbi->s_freeblocks_counter, count); | |
138 | sb->s_dirt = 1; | |
139 | } | |
140 | } | |
141 | ||
142 | static int group_reserve_blocks(struct ext2_sb_info *sbi, int group_no, | |
143 | struct ext2_group_desc *desc, struct buffer_head *bh, int count) | |
144 | { | |
145 | unsigned free_blocks; | |
146 | ||
147 | if (!desc->bg_free_blocks_count) | |
148 | return 0; | |
149 | ||
150 | spin_lock(sb_bgl_lock(sbi, group_no)); | |
151 | free_blocks = le16_to_cpu(desc->bg_free_blocks_count); | |
152 | if (free_blocks < count) | |
153 | count = free_blocks; | |
154 | desc->bg_free_blocks_count = cpu_to_le16(free_blocks - count); | |
155 | spin_unlock(sb_bgl_lock(sbi, group_no)); | |
156 | mark_buffer_dirty(bh); | |
157 | return count; | |
158 | } | |
159 | ||
160 | static void group_release_blocks(struct super_block *sb, int group_no, | |
161 | struct ext2_group_desc *desc, struct buffer_head *bh, int count) | |
162 | { | |
163 | if (count) { | |
164 | struct ext2_sb_info *sbi = EXT2_SB(sb); | |
165 | unsigned free_blocks; | |
166 | ||
167 | spin_lock(sb_bgl_lock(sbi, group_no)); | |
168 | free_blocks = le16_to_cpu(desc->bg_free_blocks_count); | |
169 | desc->bg_free_blocks_count = cpu_to_le16(free_blocks + count); | |
170 | spin_unlock(sb_bgl_lock(sbi, group_no)); | |
171 | sb->s_dirt = 1; | |
172 | mark_buffer_dirty(bh); | |
173 | } | |
174 | } | |
175 | ||
176 | /* Free given blocks, update quota and i_blocks field */ | |
177 | void ext2_free_blocks (struct inode * inode, unsigned long block, | |
178 | unsigned long count) | |
179 | { | |
180 | struct buffer_head *bitmap_bh = NULL; | |
181 | struct buffer_head * bh2; | |
182 | unsigned long block_group; | |
183 | unsigned long bit; | |
184 | unsigned long i; | |
185 | unsigned long overflow; | |
186 | struct super_block * sb = inode->i_sb; | |
187 | struct ext2_sb_info * sbi = EXT2_SB(sb); | |
188 | struct ext2_group_desc * desc; | |
189 | struct ext2_super_block * es = sbi->s_es; | |
190 | unsigned freed = 0, group_freed; | |
191 | ||
192 | if (block < le32_to_cpu(es->s_first_data_block) || | |
193 | block + count < block || | |
194 | block + count > le32_to_cpu(es->s_blocks_count)) { | |
195 | ext2_error (sb, "ext2_free_blocks", | |
196 | "Freeing blocks not in datazone - " | |
197 | "block = %lu, count = %lu", block, count); | |
198 | goto error_return; | |
199 | } | |
200 | ||
201 | ext2_debug ("freeing block(s) %lu-%lu\n", block, block + count - 1); | |
202 | ||
203 | do_more: | |
204 | overflow = 0; | |
205 | block_group = (block - le32_to_cpu(es->s_first_data_block)) / | |
206 | EXT2_BLOCKS_PER_GROUP(sb); | |
207 | bit = (block - le32_to_cpu(es->s_first_data_block)) % | |
208 | EXT2_BLOCKS_PER_GROUP(sb); | |
209 | /* | |
210 | * Check to see if we are freeing blocks across a group | |
211 | * boundary. | |
212 | */ | |
213 | if (bit + count > EXT2_BLOCKS_PER_GROUP(sb)) { | |
214 | overflow = bit + count - EXT2_BLOCKS_PER_GROUP(sb); | |
215 | count -= overflow; | |
216 | } | |
217 | brelse(bitmap_bh); | |
218 | bitmap_bh = read_block_bitmap(sb, block_group); | |
219 | if (!bitmap_bh) | |
220 | goto error_return; | |
221 | ||
222 | desc = ext2_get_group_desc (sb, block_group, &bh2); | |
223 | if (!desc) | |
224 | goto error_return; | |
225 | ||
226 | if (in_range (le32_to_cpu(desc->bg_block_bitmap), block, count) || | |
227 | in_range (le32_to_cpu(desc->bg_inode_bitmap), block, count) || | |
228 | in_range (block, le32_to_cpu(desc->bg_inode_table), | |
229 | sbi->s_itb_per_group) || | |
230 | in_range (block + count - 1, le32_to_cpu(desc->bg_inode_table), | |
231 | sbi->s_itb_per_group)) | |
232 | ext2_error (sb, "ext2_free_blocks", | |
233 | "Freeing blocks in system zones - " | |
234 | "Block = %lu, count = %lu", | |
235 | block, count); | |
236 | ||
237 | for (i = 0, group_freed = 0; i < count; i++) { | |
238 | if (!ext2_clear_bit_atomic(sb_bgl_lock(sbi, block_group), | |
239 | bit + i, bitmap_bh->b_data)) { | |
240 | ext2_error(sb, __FUNCTION__, | |
241 | "bit already cleared for block %lu", block + i); | |
242 | } else { | |
243 | group_freed++; | |
244 | } | |
245 | } | |
246 | ||
247 | mark_buffer_dirty(bitmap_bh); | |
248 | if (sb->s_flags & MS_SYNCHRONOUS) | |
249 | sync_dirty_buffer(bitmap_bh); | |
250 | ||
251 | group_release_blocks(sb, block_group, desc, bh2, group_freed); | |
252 | freed += group_freed; | |
253 | ||
254 | if (overflow) { | |
255 | block += count; | |
256 | count = overflow; | |
257 | goto do_more; | |
258 | } | |
259 | error_return: | |
260 | brelse(bitmap_bh); | |
261 | release_blocks(sb, freed); | |
262 | DQUOT_FREE_BLOCK(inode, freed); | |
263 | } | |
264 | ||
265 | static int grab_block(spinlock_t *lock, char *map, unsigned size, int goal) | |
266 | { | |
267 | int k; | |
268 | char *p, *r; | |
269 | ||
270 | if (!ext2_test_bit(goal, map)) | |
271 | goto got_it; | |
272 | ||
273 | repeat: | |
274 | if (goal) { | |
275 | /* | |
276 | * The goal was occupied; search forward for a free | |
277 | * block within the next XX blocks. | |
278 | * | |
279 | * end_goal is more or less random, but it has to be | |
280 | * less than EXT2_BLOCKS_PER_GROUP. Aligning up to the | |
281 | * next 64-bit boundary is simple.. | |
282 | */ | |
283 | k = (goal + 63) & ~63; | |
284 | goal = ext2_find_next_zero_bit(map, k, goal); | |
285 | if (goal < k) | |
286 | goto got_it; | |
287 | /* | |
288 | * Search in the remainder of the current group. | |
289 | */ | |
290 | } | |
291 | ||
292 | p = map + (goal >> 3); | |
293 | r = memscan(p, 0, (size - goal + 7) >> 3); | |
294 | k = (r - map) << 3; | |
295 | if (k < size) { | |
296 | /* | |
297 | * We have succeeded in finding a free byte in the block | |
298 | * bitmap. Now search backwards to find the start of this | |
299 | * group of free blocks - won't take more than 7 iterations. | |
300 | */ | |
301 | for (goal = k; goal && !ext2_test_bit (goal - 1, map); goal--) | |
302 | ; | |
303 | goto got_it; | |
304 | } | |
305 | ||
306 | k = ext2_find_next_zero_bit ((u32 *)map, size, goal); | |
307 | if (k < size) { | |
308 | goal = k; | |
309 | goto got_it; | |
310 | } | |
311 | return -1; | |
312 | got_it: | |
313 | if (ext2_set_bit_atomic(lock, goal, (void *) map)) | |
314 | goto repeat; | |
315 | return goal; | |
316 | } | |
317 | ||
318 | /* | |
319 | * ext2_new_block uses a goal block to assist allocation. If the goal is | |
320 | * free, or there is a free block within 32 blocks of the goal, that block | |
321 | * is allocated. Otherwise a forward search is made for a free block; within | |
322 | * each block group the search first looks for an entire free byte in the block | |
323 | * bitmap, and then for any free bit if that fails. | |
324 | * This function also updates quota and i_blocks field. | |
325 | */ | |
326 | int ext2_new_block(struct inode *inode, unsigned long goal, | |
327 | u32 *prealloc_count, u32 *prealloc_block, int *err) | |
328 | { | |
329 | struct buffer_head *bitmap_bh = NULL; | |
330 | struct buffer_head *gdp_bh; /* bh2 */ | |
331 | struct ext2_group_desc *desc; | |
332 | int group_no; /* i */ | |
333 | int ret_block; /* j */ | |
334 | int group_idx; /* k */ | |
335 | int target_block; /* tmp */ | |
336 | int block = 0; | |
337 | struct super_block *sb = inode->i_sb; | |
338 | struct ext2_sb_info *sbi = EXT2_SB(sb); | |
339 | struct ext2_super_block *es = sbi->s_es; | |
340 | unsigned group_size = EXT2_BLOCKS_PER_GROUP(sb); | |
341 | unsigned prealloc_goal = es->s_prealloc_blocks; | |
342 | unsigned group_alloc = 0, es_alloc, dq_alloc; | |
343 | int nr_scanned_groups; | |
344 | ||
345 | if (!prealloc_goal--) | |
346 | prealloc_goal = EXT2_DEFAULT_PREALLOC_BLOCKS - 1; | |
347 | if (!prealloc_count || *prealloc_count) | |
348 | prealloc_goal = 0; | |
349 | ||
350 | if (DQUOT_ALLOC_BLOCK(inode, 1)) { | |
351 | *err = -EDQUOT; | |
352 | goto out; | |
353 | } | |
354 | ||
355 | while (prealloc_goal && DQUOT_PREALLOC_BLOCK(inode, prealloc_goal)) | |
356 | prealloc_goal--; | |
357 | ||
358 | dq_alloc = prealloc_goal + 1; | |
359 | es_alloc = reserve_blocks(sb, dq_alloc); | |
360 | if (!es_alloc) { | |
361 | *err = -ENOSPC; | |
362 | goto out_dquot; | |
363 | } | |
364 | ||
365 | ext2_debug ("goal=%lu.\n", goal); | |
366 | ||
367 | if (goal < le32_to_cpu(es->s_first_data_block) || | |
368 | goal >= le32_to_cpu(es->s_blocks_count)) | |
369 | goal = le32_to_cpu(es->s_first_data_block); | |
370 | group_no = (goal - le32_to_cpu(es->s_first_data_block)) / group_size; | |
371 | desc = ext2_get_group_desc (sb, group_no, &gdp_bh); | |
372 | if (!desc) { | |
373 | /* | |
374 | * gdp_bh may still be uninitialised. But group_release_blocks | |
375 | * will not touch it because group_alloc is zero. | |
376 | */ | |
377 | goto io_error; | |
378 | } | |
379 | ||
380 | group_alloc = group_reserve_blocks(sbi, group_no, desc, | |
381 | gdp_bh, es_alloc); | |
382 | if (group_alloc) { | |
383 | ret_block = ((goal - le32_to_cpu(es->s_first_data_block)) % | |
384 | group_size); | |
385 | brelse(bitmap_bh); | |
386 | bitmap_bh = read_block_bitmap(sb, group_no); | |
387 | if (!bitmap_bh) | |
388 | goto io_error; | |
389 | ||
390 | ext2_debug("goal is at %d:%d.\n", group_no, ret_block); | |
391 | ||
392 | ret_block = grab_block(sb_bgl_lock(sbi, group_no), | |
393 | bitmap_bh->b_data, group_size, ret_block); | |
394 | if (ret_block >= 0) | |
395 | goto got_block; | |
396 | group_release_blocks(sb, group_no, desc, gdp_bh, group_alloc); | |
397 | group_alloc = 0; | |
398 | } | |
399 | ||
400 | ext2_debug ("Bit not found in block group %d.\n", group_no); | |
401 | ||
402 | /* | |
403 | * Now search the rest of the groups. We assume that | |
404 | * i and desc correctly point to the last group visited. | |
405 | */ | |
406 | nr_scanned_groups = 0; | |
407 | retry: | |
408 | for (group_idx = 0; !group_alloc && | |
409 | group_idx < sbi->s_groups_count; group_idx++) { | |
410 | group_no++; | |
411 | if (group_no >= sbi->s_groups_count) | |
412 | group_no = 0; | |
413 | desc = ext2_get_group_desc(sb, group_no, &gdp_bh); | |
414 | if (!desc) | |
415 | goto io_error; | |
416 | group_alloc = group_reserve_blocks(sbi, group_no, desc, | |
417 | gdp_bh, es_alloc); | |
418 | } | |
419 | if (!group_alloc) { | |
420 | *err = -ENOSPC; | |
421 | goto out_release; | |
422 | } | |
423 | brelse(bitmap_bh); | |
424 | bitmap_bh = read_block_bitmap(sb, group_no); | |
425 | if (!bitmap_bh) | |
426 | goto io_error; | |
427 | ||
428 | ret_block = grab_block(sb_bgl_lock(sbi, group_no), bitmap_bh->b_data, | |
429 | group_size, 0); | |
430 | if (ret_block < 0) { | |
431 | /* | |
432 | * If a free block counter is corrupted we can loop inifintely. | |
433 | * Detect that here. | |
434 | */ | |
435 | nr_scanned_groups++; | |
436 | if (nr_scanned_groups > 2 * sbi->s_groups_count) { | |
437 | ext2_error(sb, "ext2_new_block", | |
438 | "corrupted free blocks counters"); | |
439 | goto io_error; | |
440 | } | |
441 | /* | |
442 | * Someone else grabbed the last free block in this blockgroup | |
443 | * before us. Retry the scan. | |
444 | */ | |
445 | group_release_blocks(sb, group_no, desc, gdp_bh, group_alloc); | |
446 | group_alloc = 0; | |
447 | goto retry; | |
448 | } | |
449 | ||
450 | got_block: | |
451 | ext2_debug("using block group %d(%d)\n", | |
452 | group_no, desc->bg_free_blocks_count); | |
453 | ||
454 | target_block = ret_block + group_no * group_size + | |
455 | le32_to_cpu(es->s_first_data_block); | |
456 | ||
457 | if (target_block == le32_to_cpu(desc->bg_block_bitmap) || | |
458 | target_block == le32_to_cpu(desc->bg_inode_bitmap) || | |
459 | in_range(target_block, le32_to_cpu(desc->bg_inode_table), | |
460 | sbi->s_itb_per_group)) | |
461 | ext2_error (sb, "ext2_new_block", | |
462 | "Allocating block in system zone - " | |
463 | "block = %u", target_block); | |
464 | ||
465 | if (target_block >= le32_to_cpu(es->s_blocks_count)) { | |
466 | ext2_error (sb, "ext2_new_block", | |
467 | "block(%d) >= blocks count(%d) - " | |
468 | "block_group = %d, es == %p ", ret_block, | |
469 | le32_to_cpu(es->s_blocks_count), group_no, es); | |
470 | goto io_error; | |
471 | } | |
472 | block = target_block; | |
473 | ||
474 | /* OK, we _had_ allocated something */ | |
475 | ext2_debug("found bit %d\n", ret_block); | |
476 | ||
477 | dq_alloc--; | |
478 | es_alloc--; | |
479 | group_alloc--; | |
480 | ||
481 | /* | |
482 | * Do block preallocation now if required. | |
483 | */ | |
484 | write_lock(&EXT2_I(inode)->i_meta_lock); | |
485 | if (group_alloc && !*prealloc_count) { | |
486 | unsigned n; | |
487 | ||
488 | for (n = 0; n < group_alloc && ++ret_block < group_size; n++) { | |
489 | if (ext2_set_bit_atomic(sb_bgl_lock(sbi, group_no), | |
490 | ret_block, | |
491 | (void*) bitmap_bh->b_data)) | |
492 | break; | |
493 | } | |
494 | *prealloc_block = block + 1; | |
495 | *prealloc_count = n; | |
496 | es_alloc -= n; | |
497 | dq_alloc -= n; | |
498 | group_alloc -= n; | |
499 | } | |
500 | write_unlock(&EXT2_I(inode)->i_meta_lock); | |
501 | ||
502 | mark_buffer_dirty(bitmap_bh); | |
503 | if (sb->s_flags & MS_SYNCHRONOUS) | |
504 | sync_dirty_buffer(bitmap_bh); | |
505 | ||
506 | ext2_debug ("allocating block %d. ", block); | |
507 | ||
508 | *err = 0; | |
509 | out_release: | |
510 | group_release_blocks(sb, group_no, desc, gdp_bh, group_alloc); | |
511 | release_blocks(sb, es_alloc); | |
512 | out_dquot: | |
513 | DQUOT_FREE_BLOCK(inode, dq_alloc); | |
514 | out: | |
515 | brelse(bitmap_bh); | |
516 | return block; | |
517 | ||
518 | io_error: | |
519 | *err = -EIO; | |
520 | goto out_release; | |
521 | } | |
522 | ||
21730eed VH |
523 | #ifdef EXT2FS_DEBUG |
524 | ||
525 | static int nibblemap[] = {4, 3, 3, 2, 3, 2, 2, 1, 3, 2, 2, 1, 2, 1, 1, 0}; | |
526 | ||
527 | unsigned long ext2_count_free (struct buffer_head * map, unsigned int numchars) | |
528 | { | |
529 | unsigned int i; | |
530 | unsigned long sum = 0; | |
531 | ||
532 | if (!map) | |
533 | return (0); | |
534 | for (i = 0; i < numchars; i++) | |
535 | sum += nibblemap[map->b_data[i] & 0xf] + | |
536 | nibblemap[(map->b_data[i] >> 4) & 0xf]; | |
537 | return (sum); | |
538 | } | |
539 | ||
540 | #endif /* EXT2FS_DEBUG */ | |
541 | ||
1da177e4 LT |
542 | unsigned long ext2_count_free_blocks (struct super_block * sb) |
543 | { | |
544 | struct ext2_group_desc * desc; | |
545 | unsigned long desc_count = 0; | |
546 | int i; | |
547 | #ifdef EXT2FS_DEBUG | |
548 | unsigned long bitmap_count, x; | |
549 | struct ext2_super_block *es; | |
550 | ||
1da177e4 LT |
551 | es = EXT2_SB(sb)->s_es; |
552 | desc_count = 0; | |
553 | bitmap_count = 0; | |
554 | desc = NULL; | |
555 | for (i = 0; i < EXT2_SB(sb)->s_groups_count; i++) { | |
556 | struct buffer_head *bitmap_bh; | |
557 | desc = ext2_get_group_desc (sb, i, NULL); | |
558 | if (!desc) | |
559 | continue; | |
560 | desc_count += le16_to_cpu(desc->bg_free_blocks_count); | |
561 | bitmap_bh = read_block_bitmap(sb, i); | |
562 | if (!bitmap_bh) | |
563 | continue; | |
564 | ||
565 | x = ext2_count_free(bitmap_bh, sb->s_blocksize); | |
566 | printk ("group %d: stored = %d, counted = %lu\n", | |
567 | i, le16_to_cpu(desc->bg_free_blocks_count), x); | |
568 | bitmap_count += x; | |
569 | brelse(bitmap_bh); | |
570 | } | |
571 | printk("ext2_count_free_blocks: stored = %lu, computed = %lu, %lu\n", | |
572 | (long)le32_to_cpu(es->s_free_blocks_count), | |
573 | desc_count, bitmap_count); | |
1da177e4 LT |
574 | return bitmap_count; |
575 | #else | |
576 | for (i = 0; i < EXT2_SB(sb)->s_groups_count; i++) { | |
577 | desc = ext2_get_group_desc (sb, i, NULL); | |
578 | if (!desc) | |
579 | continue; | |
580 | desc_count += le16_to_cpu(desc->bg_free_blocks_count); | |
581 | } | |
582 | return desc_count; | |
583 | #endif | |
584 | } | |
585 | ||
586 | static inline int | |
587 | block_in_use(unsigned long block, struct super_block *sb, unsigned char *map) | |
588 | { | |
589 | return ext2_test_bit ((block - | |
590 | le32_to_cpu(EXT2_SB(sb)->s_es->s_first_data_block)) % | |
591 | EXT2_BLOCKS_PER_GROUP(sb), map); | |
592 | } | |
593 | ||
594 | static inline int test_root(int a, int b) | |
595 | { | |
596 | int num = b; | |
597 | ||
598 | while (a > num) | |
599 | num *= b; | |
600 | return num == a; | |
601 | } | |
602 | ||
603 | static int ext2_group_sparse(int group) | |
604 | { | |
605 | if (group <= 1) | |
606 | return 1; | |
607 | return (test_root(group, 3) || test_root(group, 5) || | |
608 | test_root(group, 7)); | |
609 | } | |
610 | ||
611 | /** | |
612 | * ext2_bg_has_super - number of blocks used by the superblock in group | |
613 | * @sb: superblock for filesystem | |
614 | * @group: group number to check | |
615 | * | |
616 | * Return the number of blocks used by the superblock (primary or backup) | |
617 | * in this group. Currently this will be only 0 or 1. | |
618 | */ | |
619 | int ext2_bg_has_super(struct super_block *sb, int group) | |
620 | { | |
621 | if (EXT2_HAS_RO_COMPAT_FEATURE(sb,EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER)&& | |
622 | !ext2_group_sparse(group)) | |
623 | return 0; | |
624 | return 1; | |
625 | } | |
626 | ||
627 | /** | |
628 | * ext2_bg_num_gdb - number of blocks used by the group table in group | |
629 | * @sb: superblock for filesystem | |
630 | * @group: group number to check | |
631 | * | |
632 | * Return the number of blocks used by the group descriptor table | |
633 | * (primary or backup) in this group. In the future there may be a | |
634 | * different number of descriptor blocks in each group. | |
635 | */ | |
636 | unsigned long ext2_bg_num_gdb(struct super_block *sb, int group) | |
637 | { | |
638 | if (EXT2_HAS_RO_COMPAT_FEATURE(sb,EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER)&& | |
639 | !ext2_group_sparse(group)) | |
640 | return 0; | |
641 | return EXT2_SB(sb)->s_gdb_count; | |
642 | } | |
643 |