Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * linux/fs/ext3/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 | 14 | #include <linux/time.h> |
16f7e0fe | 15 | #include <linux/capability.h> |
1da177e4 LT |
16 | #include <linux/fs.h> |
17 | #include <linux/jbd.h> | |
18 | #include <linux/ext3_fs.h> | |
19 | #include <linux/ext3_jbd.h> | |
20 | #include <linux/quotaops.h> | |
21 | #include <linux/buffer_head.h> | |
22 | ||
23 | /* | |
24 | * balloc.c contains the blocks allocation and deallocation routines | |
25 | */ | |
26 | ||
27 | /* | |
28 | * The free blocks are managed by bitmaps. A file system contains several | |
29 | * blocks groups. Each group contains 1 bitmap block for blocks, 1 bitmap | |
30 | * block for inodes, N blocks for the inode table and data blocks. | |
31 | * | |
32 | * The file system contains group descriptors which are located after the | |
33 | * super block. Each descriptor contains the number of the bitmap block and | |
34 | * the free blocks count in the block. The descriptors are loaded in memory | |
35 | * when a file system is mounted (see ext3_read_super). | |
36 | */ | |
37 | ||
38 | ||
39 | #define in_range(b, first, len) ((b) >= (first) && (b) <= (first) + (len) - 1) | |
40 | ||
41 | struct ext3_group_desc * ext3_get_group_desc(struct super_block * sb, | |
42 | unsigned int block_group, | |
43 | struct buffer_head ** bh) | |
44 | { | |
45 | unsigned long group_desc; | |
46 | unsigned long offset; | |
47 | struct ext3_group_desc * desc; | |
48 | struct ext3_sb_info *sbi = EXT3_SB(sb); | |
49 | ||
50 | if (block_group >= sbi->s_groups_count) { | |
51 | ext3_error (sb, "ext3_get_group_desc", | |
52 | "block_group >= groups_count - " | |
53 | "block_group = %d, groups_count = %lu", | |
54 | block_group, sbi->s_groups_count); | |
55 | ||
56 | return NULL; | |
57 | } | |
58 | smp_rmb(); | |
59 | ||
60 | group_desc = block_group >> EXT3_DESC_PER_BLOCK_BITS(sb); | |
61 | offset = block_group & (EXT3_DESC_PER_BLOCK(sb) - 1); | |
62 | if (!sbi->s_group_desc[group_desc]) { | |
63 | ext3_error (sb, "ext3_get_group_desc", | |
64 | "Group descriptor not loaded - " | |
65 | "block_group = %d, group_desc = %lu, desc = %lu", | |
66 | block_group, group_desc, offset); | |
67 | return NULL; | |
68 | } | |
69 | ||
70 | desc = (struct ext3_group_desc *) sbi->s_group_desc[group_desc]->b_data; | |
71 | if (bh) | |
72 | *bh = sbi->s_group_desc[group_desc]; | |
73 | return desc + offset; | |
74 | } | |
75 | ||
76 | /* | |
77 | * Read the bitmap for a given block_group, reading into the specified | |
78 | * slot in the superblock's bitmap cache. | |
79 | * | |
80 | * Return buffer_head on success or NULL in case of failure. | |
81 | */ | |
82 | static struct buffer_head * | |
83 | read_block_bitmap(struct super_block *sb, unsigned int block_group) | |
84 | { | |
85 | struct ext3_group_desc * desc; | |
86 | struct buffer_head * bh = NULL; | |
87 | ||
88 | desc = ext3_get_group_desc (sb, block_group, NULL); | |
89 | if (!desc) | |
90 | goto error_out; | |
91 | bh = sb_bread(sb, le32_to_cpu(desc->bg_block_bitmap)); | |
92 | if (!bh) | |
93 | ext3_error (sb, "read_block_bitmap", | |
94 | "Cannot read block bitmap - " | |
95 | "block_group = %d, block_bitmap = %u", | |
96 | block_group, le32_to_cpu(desc->bg_block_bitmap)); | |
97 | error_out: | |
98 | return bh; | |
99 | } | |
100 | /* | |
101 | * The reservation window structure operations | |
102 | * -------------------------------------------- | |
103 | * Operations include: | |
104 | * dump, find, add, remove, is_empty, find_next_reservable_window, etc. | |
105 | * | |
106 | * We use sorted double linked list for the per-filesystem reservation | |
107 | * window list. (like in vm_region). | |
108 | * | |
109 | * Initially, we keep those small operations in the abstract functions, | |
110 | * so later if we need a better searching tree than double linked-list, | |
111 | * we could easily switch to that without changing too much | |
112 | * code. | |
113 | */ | |
114 | #if 0 | |
115 | static void __rsv_window_dump(struct rb_root *root, int verbose, | |
116 | const char *fn) | |
117 | { | |
118 | struct rb_node *n; | |
119 | struct ext3_reserve_window_node *rsv, *prev; | |
120 | int bad; | |
121 | ||
122 | restart: | |
123 | n = rb_first(root); | |
124 | bad = 0; | |
125 | prev = NULL; | |
126 | ||
127 | printk("Block Allocation Reservation Windows Map (%s):\n", fn); | |
128 | while (n) { | |
129 | rsv = list_entry(n, struct ext3_reserve_window_node, rsv_node); | |
130 | if (verbose) | |
131 | printk("reservation window 0x%p " | |
132 | "start: %d, end: %d\n", | |
133 | rsv, rsv->rsv_start, rsv->rsv_end); | |
134 | if (rsv->rsv_start && rsv->rsv_start >= rsv->rsv_end) { | |
135 | printk("Bad reservation %p (start >= end)\n", | |
136 | rsv); | |
137 | bad = 1; | |
138 | } | |
139 | if (prev && prev->rsv_end >= rsv->rsv_start) { | |
140 | printk("Bad reservation %p (prev->end >= start)\n", | |
141 | rsv); | |
142 | bad = 1; | |
143 | } | |
144 | if (bad) { | |
145 | if (!verbose) { | |
146 | printk("Restarting reservation walk in verbose mode\n"); | |
147 | verbose = 1; | |
148 | goto restart; | |
149 | } | |
150 | } | |
151 | n = rb_next(n); | |
152 | prev = rsv; | |
153 | } | |
154 | printk("Window map complete.\n"); | |
155 | if (bad) | |
156 | BUG(); | |
157 | } | |
158 | #define rsv_window_dump(root, verbose) \ | |
159 | __rsv_window_dump((root), (verbose), __FUNCTION__) | |
160 | #else | |
161 | #define rsv_window_dump(root, verbose) do {} while (0) | |
162 | #endif | |
163 | ||
164 | static int | |
1c2bf374 | 165 | goal_in_my_reservation(struct ext3_reserve_window *rsv, ext3_grpblk_t grp_goal, |
1da177e4 LT |
166 | unsigned int group, struct super_block * sb) |
167 | { | |
1c2bf374 | 168 | ext3_fsblk_t group_first_block, group_last_block; |
1da177e4 | 169 | |
43d23f90 | 170 | group_first_block = ext3_group_first_block_no(sb, group); |
1da177e4 LT |
171 | group_last_block = group_first_block + EXT3_BLOCKS_PER_GROUP(sb) - 1; |
172 | ||
173 | if ((rsv->_rsv_start > group_last_block) || | |
174 | (rsv->_rsv_end < group_first_block)) | |
175 | return 0; | |
1c2bf374 MC |
176 | if ((grp_goal >= 0) && ((grp_goal + group_first_block < rsv->_rsv_start) |
177 | || (grp_goal + group_first_block > rsv->_rsv_end))) | |
1da177e4 LT |
178 | return 0; |
179 | return 1; | |
180 | } | |
181 | ||
182 | /* | |
183 | * Find the reserved window which includes the goal, or the previous one | |
184 | * if the goal is not in any window. | |
185 | * Returns NULL if there are no windows or if all windows start after the goal. | |
186 | */ | |
187 | static struct ext3_reserve_window_node * | |
1c2bf374 | 188 | search_reserve_window(struct rb_root *root, ext3_fsblk_t goal) |
1da177e4 LT |
189 | { |
190 | struct rb_node *n = root->rb_node; | |
191 | struct ext3_reserve_window_node *rsv; | |
192 | ||
193 | if (!n) | |
194 | return NULL; | |
195 | ||
196 | do { | |
197 | rsv = rb_entry(n, struct ext3_reserve_window_node, rsv_node); | |
198 | ||
199 | if (goal < rsv->rsv_start) | |
200 | n = n->rb_left; | |
201 | else if (goal > rsv->rsv_end) | |
202 | n = n->rb_right; | |
203 | else | |
204 | return rsv; | |
205 | } while (n); | |
206 | /* | |
207 | * We've fallen off the end of the tree: the goal wasn't inside | |
208 | * any particular node. OK, the previous node must be to one | |
209 | * side of the interval containing the goal. If it's the RHS, | |
210 | * we need to back up one. | |
211 | */ | |
212 | if (rsv->rsv_start > goal) { | |
213 | n = rb_prev(&rsv->rsv_node); | |
214 | rsv = rb_entry(n, struct ext3_reserve_window_node, rsv_node); | |
215 | } | |
216 | return rsv; | |
217 | } | |
218 | ||
219 | void ext3_rsv_window_add(struct super_block *sb, | |
220 | struct ext3_reserve_window_node *rsv) | |
221 | { | |
222 | struct rb_root *root = &EXT3_SB(sb)->s_rsv_window_root; | |
223 | struct rb_node *node = &rsv->rsv_node; | |
1c2bf374 | 224 | ext3_fsblk_t start = rsv->rsv_start; |
1da177e4 LT |
225 | |
226 | struct rb_node ** p = &root->rb_node; | |
227 | struct rb_node * parent = NULL; | |
228 | struct ext3_reserve_window_node *this; | |
229 | ||
230 | while (*p) | |
231 | { | |
232 | parent = *p; | |
233 | this = rb_entry(parent, struct ext3_reserve_window_node, rsv_node); | |
234 | ||
235 | if (start < this->rsv_start) | |
236 | p = &(*p)->rb_left; | |
237 | else if (start > this->rsv_end) | |
238 | p = &(*p)->rb_right; | |
239 | else | |
240 | BUG(); | |
241 | } | |
242 | ||
243 | rb_link_node(node, parent, p); | |
244 | rb_insert_color(node, root); | |
245 | } | |
246 | ||
247 | static void rsv_window_remove(struct super_block *sb, | |
248 | struct ext3_reserve_window_node *rsv) | |
249 | { | |
250 | rsv->rsv_start = EXT3_RESERVE_WINDOW_NOT_ALLOCATED; | |
251 | rsv->rsv_end = EXT3_RESERVE_WINDOW_NOT_ALLOCATED; | |
252 | rsv->rsv_alloc_hit = 0; | |
253 | rb_erase(&rsv->rsv_node, &EXT3_SB(sb)->s_rsv_window_root); | |
254 | } | |
255 | ||
256 | static inline int rsv_is_empty(struct ext3_reserve_window *rsv) | |
257 | { | |
258 | /* a valid reservation end block could not be 0 */ | |
259 | return (rsv->_rsv_end == EXT3_RESERVE_WINDOW_NOT_ALLOCATED); | |
260 | } | |
261 | void ext3_init_block_alloc_info(struct inode *inode) | |
262 | { | |
263 | struct ext3_inode_info *ei = EXT3_I(inode); | |
264 | struct ext3_block_alloc_info *block_i = ei->i_block_alloc_info; | |
265 | struct super_block *sb = inode->i_sb; | |
266 | ||
267 | block_i = kmalloc(sizeof(*block_i), GFP_NOFS); | |
268 | if (block_i) { | |
269 | struct ext3_reserve_window_node *rsv = &block_i->rsv_window_node; | |
270 | ||
271 | rsv->rsv_start = EXT3_RESERVE_WINDOW_NOT_ALLOCATED; | |
272 | rsv->rsv_end = EXT3_RESERVE_WINDOW_NOT_ALLOCATED; | |
273 | ||
274 | /* | |
275 | * if filesystem is mounted with NORESERVATION, the goal | |
276 | * reservation window size is set to zero to indicate | |
277 | * block reservation is off | |
278 | */ | |
279 | if (!test_opt(sb, RESERVATION)) | |
280 | rsv->rsv_goal_size = 0; | |
281 | else | |
282 | rsv->rsv_goal_size = EXT3_DEFAULT_RESERVE_BLOCKS; | |
283 | rsv->rsv_alloc_hit = 0; | |
284 | block_i->last_alloc_logical_block = 0; | |
285 | block_i->last_alloc_physical_block = 0; | |
286 | } | |
287 | ei->i_block_alloc_info = block_i; | |
288 | } | |
289 | ||
290 | void ext3_discard_reservation(struct inode *inode) | |
291 | { | |
292 | struct ext3_inode_info *ei = EXT3_I(inode); | |
293 | struct ext3_block_alloc_info *block_i = ei->i_block_alloc_info; | |
294 | struct ext3_reserve_window_node *rsv; | |
295 | spinlock_t *rsv_lock = &EXT3_SB(inode->i_sb)->s_rsv_window_lock; | |
296 | ||
297 | if (!block_i) | |
298 | return; | |
299 | ||
300 | rsv = &block_i->rsv_window_node; | |
301 | if (!rsv_is_empty(&rsv->rsv_window)) { | |
302 | spin_lock(rsv_lock); | |
303 | if (!rsv_is_empty(&rsv->rsv_window)) | |
304 | rsv_window_remove(inode->i_sb, rsv); | |
305 | spin_unlock(rsv_lock); | |
306 | } | |
307 | } | |
308 | ||
309 | /* Free given blocks, update quota and i_blocks field */ | |
310 | void ext3_free_blocks_sb(handle_t *handle, struct super_block *sb, | |
1c2bf374 MC |
311 | ext3_fsblk_t block, unsigned long count, |
312 | unsigned long *pdquot_freed_blocks) | |
1da177e4 LT |
313 | { |
314 | struct buffer_head *bitmap_bh = NULL; | |
315 | struct buffer_head *gd_bh; | |
316 | unsigned long block_group; | |
1c2bf374 | 317 | ext3_grpblk_t bit; |
1da177e4 LT |
318 | unsigned long i; |
319 | unsigned long overflow; | |
320 | struct ext3_group_desc * desc; | |
321 | struct ext3_super_block * es; | |
322 | struct ext3_sb_info *sbi; | |
323 | int err = 0, ret; | |
1c2bf374 | 324 | ext3_grpblk_t group_freed; |
1da177e4 LT |
325 | |
326 | *pdquot_freed_blocks = 0; | |
327 | sbi = EXT3_SB(sb); | |
328 | es = sbi->s_es; | |
329 | if (block < le32_to_cpu(es->s_first_data_block) || | |
330 | block + count < block || | |
331 | block + count > le32_to_cpu(es->s_blocks_count)) { | |
332 | ext3_error (sb, "ext3_free_blocks", | |
333 | "Freeing blocks not in datazone - " | |
1c2bf374 | 334 | "block = "E3FSBLK", count = %lu", block, count); |
1da177e4 LT |
335 | goto error_return; |
336 | } | |
337 | ||
338 | ext3_debug ("freeing block(s) %lu-%lu\n", block, block + count - 1); | |
339 | ||
340 | do_more: | |
341 | overflow = 0; | |
342 | block_group = (block - le32_to_cpu(es->s_first_data_block)) / | |
343 | EXT3_BLOCKS_PER_GROUP(sb); | |
344 | bit = (block - le32_to_cpu(es->s_first_data_block)) % | |
345 | EXT3_BLOCKS_PER_GROUP(sb); | |
346 | /* | |
347 | * Check to see if we are freeing blocks across a group | |
348 | * boundary. | |
349 | */ | |
350 | if (bit + count > EXT3_BLOCKS_PER_GROUP(sb)) { | |
351 | overflow = bit + count - EXT3_BLOCKS_PER_GROUP(sb); | |
352 | count -= overflow; | |
353 | } | |
354 | brelse(bitmap_bh); | |
355 | bitmap_bh = read_block_bitmap(sb, block_group); | |
356 | if (!bitmap_bh) | |
357 | goto error_return; | |
358 | desc = ext3_get_group_desc (sb, block_group, &gd_bh); | |
359 | if (!desc) | |
360 | goto error_return; | |
361 | ||
362 | if (in_range (le32_to_cpu(desc->bg_block_bitmap), block, count) || | |
363 | in_range (le32_to_cpu(desc->bg_inode_bitmap), block, count) || | |
364 | in_range (block, le32_to_cpu(desc->bg_inode_table), | |
365 | sbi->s_itb_per_group) || | |
366 | in_range (block + count - 1, le32_to_cpu(desc->bg_inode_table), | |
367 | sbi->s_itb_per_group)) | |
368 | ext3_error (sb, "ext3_free_blocks", | |
369 | "Freeing blocks in system zones - " | |
1c2bf374 | 370 | "Block = "E3FSBLK", count = %lu", |
1da177e4 LT |
371 | block, count); |
372 | ||
373 | /* | |
374 | * We are about to start releasing blocks in the bitmap, | |
375 | * so we need undo access. | |
376 | */ | |
377 | /* @@@ check errors */ | |
378 | BUFFER_TRACE(bitmap_bh, "getting undo access"); | |
379 | err = ext3_journal_get_undo_access(handle, bitmap_bh); | |
380 | if (err) | |
381 | goto error_return; | |
382 | ||
383 | /* | |
384 | * We are about to modify some metadata. Call the journal APIs | |
385 | * to unshare ->b_data if a currently-committing transaction is | |
386 | * using it | |
387 | */ | |
388 | BUFFER_TRACE(gd_bh, "get_write_access"); | |
389 | err = ext3_journal_get_write_access(handle, gd_bh); | |
390 | if (err) | |
391 | goto error_return; | |
392 | ||
393 | jbd_lock_bh_state(bitmap_bh); | |
394 | ||
395 | for (i = 0, group_freed = 0; i < count; i++) { | |
396 | /* | |
397 | * An HJ special. This is expensive... | |
398 | */ | |
399 | #ifdef CONFIG_JBD_DEBUG | |
400 | jbd_unlock_bh_state(bitmap_bh); | |
401 | { | |
402 | struct buffer_head *debug_bh; | |
403 | debug_bh = sb_find_get_block(sb, block + i); | |
404 | if (debug_bh) { | |
405 | BUFFER_TRACE(debug_bh, "Deleted!"); | |
406 | if (!bh2jh(bitmap_bh)->b_committed_data) | |
407 | BUFFER_TRACE(debug_bh, | |
408 | "No commited data in bitmap"); | |
409 | BUFFER_TRACE2(debug_bh, bitmap_bh, "bitmap"); | |
410 | __brelse(debug_bh); | |
411 | } | |
412 | } | |
413 | jbd_lock_bh_state(bitmap_bh); | |
414 | #endif | |
415 | if (need_resched()) { | |
416 | jbd_unlock_bh_state(bitmap_bh); | |
417 | cond_resched(); | |
418 | jbd_lock_bh_state(bitmap_bh); | |
419 | } | |
420 | /* @@@ This prevents newly-allocated data from being | |
421 | * freed and then reallocated within the same | |
422 | * transaction. | |
423 | * | |
424 | * Ideally we would want to allow that to happen, but to | |
425 | * do so requires making journal_forget() capable of | |
426 | * revoking the queued write of a data block, which | |
427 | * implies blocking on the journal lock. *forget() | |
428 | * cannot block due to truncate races. | |
429 | * | |
430 | * Eventually we can fix this by making journal_forget() | |
431 | * return a status indicating whether or not it was able | |
432 | * to revoke the buffer. On successful revoke, it is | |
433 | * safe not to set the allocation bit in the committed | |
434 | * bitmap, because we know that there is no outstanding | |
435 | * activity on the buffer any more and so it is safe to | |
436 | * reallocate it. | |
437 | */ | |
438 | BUFFER_TRACE(bitmap_bh, "set in b_committed_data"); | |
439 | J_ASSERT_BH(bitmap_bh, | |
440 | bh2jh(bitmap_bh)->b_committed_data != NULL); | |
441 | ext3_set_bit_atomic(sb_bgl_lock(sbi, block_group), bit + i, | |
442 | bh2jh(bitmap_bh)->b_committed_data); | |
443 | ||
444 | /* | |
445 | * We clear the bit in the bitmap after setting the committed | |
446 | * data bit, because this is the reverse order to that which | |
447 | * the allocator uses. | |
448 | */ | |
449 | BUFFER_TRACE(bitmap_bh, "clear bit"); | |
450 | if (!ext3_clear_bit_atomic(sb_bgl_lock(sbi, block_group), | |
451 | bit + i, bitmap_bh->b_data)) { | |
452 | jbd_unlock_bh_state(bitmap_bh); | |
453 | ext3_error(sb, __FUNCTION__, | |
1c2bf374 MC |
454 | "bit already cleared for block "E3FSBLK, |
455 | block + i); | |
1da177e4 LT |
456 | jbd_lock_bh_state(bitmap_bh); |
457 | BUFFER_TRACE(bitmap_bh, "bit already cleared"); | |
458 | } else { | |
459 | group_freed++; | |
460 | } | |
461 | } | |
462 | jbd_unlock_bh_state(bitmap_bh); | |
463 | ||
464 | spin_lock(sb_bgl_lock(sbi, block_group)); | |
465 | desc->bg_free_blocks_count = | |
466 | cpu_to_le16(le16_to_cpu(desc->bg_free_blocks_count) + | |
467 | group_freed); | |
468 | spin_unlock(sb_bgl_lock(sbi, block_group)); | |
469 | percpu_counter_mod(&sbi->s_freeblocks_counter, count); | |
470 | ||
471 | /* We dirtied the bitmap block */ | |
472 | BUFFER_TRACE(bitmap_bh, "dirtied bitmap block"); | |
473 | err = ext3_journal_dirty_metadata(handle, bitmap_bh); | |
474 | ||
475 | /* And the group descriptor block */ | |
476 | BUFFER_TRACE(gd_bh, "dirtied group descriptor block"); | |
477 | ret = ext3_journal_dirty_metadata(handle, gd_bh); | |
478 | if (!err) err = ret; | |
479 | *pdquot_freed_blocks += group_freed; | |
480 | ||
481 | if (overflow && !err) { | |
482 | block += count; | |
483 | count = overflow; | |
484 | goto do_more; | |
485 | } | |
486 | sb->s_dirt = 1; | |
487 | error_return: | |
488 | brelse(bitmap_bh); | |
489 | ext3_std_error(sb, err); | |
490 | return; | |
491 | } | |
492 | ||
493 | /* Free given blocks, update quota and i_blocks field */ | |
494 | void ext3_free_blocks(handle_t *handle, struct inode *inode, | |
1c2bf374 | 495 | ext3_fsblk_t block, unsigned long count) |
1da177e4 LT |
496 | { |
497 | struct super_block * sb; | |
1c2bf374 | 498 | unsigned long dquot_freed_blocks; |
1da177e4 LT |
499 | |
500 | sb = inode->i_sb; | |
501 | if (!sb) { | |
502 | printk ("ext3_free_blocks: nonexistent device"); | |
503 | return; | |
504 | } | |
505 | ext3_free_blocks_sb(handle, sb, block, count, &dquot_freed_blocks); | |
506 | if (dquot_freed_blocks) | |
507 | DQUOT_FREE_BLOCK(inode, dquot_freed_blocks); | |
508 | return; | |
509 | } | |
510 | ||
511 | /* | |
512 | * For ext3 allocations, we must not reuse any blocks which are | |
513 | * allocated in the bitmap buffer's "last committed data" copy. This | |
514 | * prevents deletes from freeing up the page for reuse until we have | |
515 | * committed the delete transaction. | |
516 | * | |
517 | * If we didn't do this, then deleting something and reallocating it as | |
518 | * data would allow the old block to be overwritten before the | |
519 | * transaction committed (because we force data to disk before commit). | |
520 | * This would lead to corruption if we crashed between overwriting the | |
521 | * data and committing the delete. | |
522 | * | |
523 | * @@@ We may want to make this allocation behaviour conditional on | |
524 | * data-writes at some point, and disable it for metadata allocations or | |
525 | * sync-data inodes. | |
526 | */ | |
1c2bf374 | 527 | static int ext3_test_allocatable(ext3_grpblk_t nr, struct buffer_head *bh) |
1da177e4 LT |
528 | { |
529 | int ret; | |
530 | struct journal_head *jh = bh2jh(bh); | |
531 | ||
532 | if (ext3_test_bit(nr, bh->b_data)) | |
533 | return 0; | |
534 | ||
535 | jbd_lock_bh_state(bh); | |
536 | if (!jh->b_committed_data) | |
537 | ret = 1; | |
538 | else | |
539 | ret = !ext3_test_bit(nr, jh->b_committed_data); | |
540 | jbd_unlock_bh_state(bh); | |
541 | return ret; | |
542 | } | |
543 | ||
1c2bf374 MC |
544 | static ext3_grpblk_t |
545 | bitmap_search_next_usable_block(ext3_grpblk_t start, struct buffer_head *bh, | |
546 | ext3_grpblk_t maxblocks) | |
1da177e4 | 547 | { |
1c2bf374 | 548 | ext3_grpblk_t next; |
1da177e4 LT |
549 | struct journal_head *jh = bh2jh(bh); |
550 | ||
551 | /* | |
552 | * The bitmap search --- search forward alternately through the actual | |
553 | * bitmap and the last-committed copy until we find a bit free in | |
554 | * both | |
555 | */ | |
556 | while (start < maxblocks) { | |
557 | next = ext3_find_next_zero_bit(bh->b_data, maxblocks, start); | |
558 | if (next >= maxblocks) | |
559 | return -1; | |
560 | if (ext3_test_allocatable(next, bh)) | |
561 | return next; | |
562 | jbd_lock_bh_state(bh); | |
563 | if (jh->b_committed_data) | |
564 | start = ext3_find_next_zero_bit(jh->b_committed_data, | |
565 | maxblocks, next); | |
566 | jbd_unlock_bh_state(bh); | |
567 | } | |
568 | return -1; | |
569 | } | |
570 | ||
571 | /* | |
572 | * Find an allocatable block in a bitmap. We honour both the bitmap and | |
573 | * its last-committed copy (if that exists), and perform the "most | |
574 | * appropriate allocation" algorithm of looking for a free block near | |
575 | * the initial goal; then for a free byte somewhere in the bitmap; then | |
576 | * for any free bit in the bitmap. | |
577 | */ | |
1c2bf374 MC |
578 | static ext3_grpblk_t |
579 | find_next_usable_block(ext3_grpblk_t start, struct buffer_head *bh, | |
580 | ext3_grpblk_t maxblocks) | |
1da177e4 | 581 | { |
1c2bf374 | 582 | ext3_grpblk_t here, next; |
1da177e4 LT |
583 | char *p, *r; |
584 | ||
585 | if (start > 0) { | |
586 | /* | |
587 | * The goal was occupied; search forward for a free | |
588 | * block within the next XX blocks. | |
589 | * | |
590 | * end_goal is more or less random, but it has to be | |
591 | * less than EXT3_BLOCKS_PER_GROUP. Aligning up to the | |
592 | * next 64-bit boundary is simple.. | |
593 | */ | |
1c2bf374 | 594 | ext3_grpblk_t end_goal = (start + 63) & ~63; |
1da177e4 LT |
595 | if (end_goal > maxblocks) |
596 | end_goal = maxblocks; | |
597 | here = ext3_find_next_zero_bit(bh->b_data, end_goal, start); | |
598 | if (here < end_goal && ext3_test_allocatable(here, bh)) | |
599 | return here; | |
600 | ext3_debug("Bit not found near goal\n"); | |
601 | } | |
602 | ||
603 | here = start; | |
604 | if (here < 0) | |
605 | here = 0; | |
606 | ||
607 | p = ((char *)bh->b_data) + (here >> 3); | |
608 | r = memscan(p, 0, (maxblocks - here + 7) >> 3); | |
609 | next = (r - ((char *)bh->b_data)) << 3; | |
610 | ||
611 | if (next < maxblocks && next >= start && ext3_test_allocatable(next, bh)) | |
612 | return next; | |
613 | ||
614 | /* | |
615 | * The bitmap search --- search forward alternately through the actual | |
616 | * bitmap and the last-committed copy until we find a bit free in | |
617 | * both | |
618 | */ | |
619 | here = bitmap_search_next_usable_block(here, bh, maxblocks); | |
620 | return here; | |
621 | } | |
622 | ||
623 | /* | |
624 | * We think we can allocate this block in this bitmap. Try to set the bit. | |
625 | * If that succeeds then check that nobody has allocated and then freed the | |
626 | * block since we saw that is was not marked in b_committed_data. If it _was_ | |
627 | * allocated and freed then clear the bit in the bitmap again and return | |
628 | * zero (failure). | |
629 | */ | |
630 | static inline int | |
1c2bf374 | 631 | claim_block(spinlock_t *lock, ext3_grpblk_t block, struct buffer_head *bh) |
1da177e4 LT |
632 | { |
633 | struct journal_head *jh = bh2jh(bh); | |
634 | int ret; | |
635 | ||
636 | if (ext3_set_bit_atomic(lock, block, bh->b_data)) | |
637 | return 0; | |
638 | jbd_lock_bh_state(bh); | |
639 | if (jh->b_committed_data && ext3_test_bit(block,jh->b_committed_data)) { | |
640 | ext3_clear_bit_atomic(lock, block, bh->b_data); | |
641 | ret = 0; | |
642 | } else { | |
643 | ret = 1; | |
644 | } | |
645 | jbd_unlock_bh_state(bh); | |
646 | return ret; | |
647 | } | |
648 | ||
649 | /* | |
650 | * If we failed to allocate the desired block then we may end up crossing to a | |
651 | * new bitmap. In that case we must release write access to the old one via | |
652 | * ext3_journal_release_buffer(), else we'll run out of credits. | |
653 | */ | |
1c2bf374 | 654 | static ext3_grpblk_t |
1da177e4 | 655 | ext3_try_to_allocate(struct super_block *sb, handle_t *handle, int group, |
1c2bf374 | 656 | struct buffer_head *bitmap_bh, ext3_grpblk_t grp_goal, |
b54e41ec | 657 | unsigned long *count, struct ext3_reserve_window *my_rsv) |
1da177e4 | 658 | { |
1c2bf374 MC |
659 | ext3_fsblk_t group_first_block; |
660 | ext3_grpblk_t start, end; | |
b54e41ec | 661 | unsigned long num = 0; |
1da177e4 LT |
662 | |
663 | /* we do allocation within the reservation window if we have a window */ | |
664 | if (my_rsv) { | |
43d23f90 | 665 | group_first_block = ext3_group_first_block_no(sb, group); |
1da177e4 LT |
666 | if (my_rsv->_rsv_start >= group_first_block) |
667 | start = my_rsv->_rsv_start - group_first_block; | |
668 | else | |
669 | /* reservation window cross group boundary */ | |
670 | start = 0; | |
671 | end = my_rsv->_rsv_end - group_first_block + 1; | |
672 | if (end > EXT3_BLOCKS_PER_GROUP(sb)) | |
673 | /* reservation window crosses group boundary */ | |
674 | end = EXT3_BLOCKS_PER_GROUP(sb); | |
1c2bf374 MC |
675 | if ((start <= grp_goal) && (grp_goal < end)) |
676 | start = grp_goal; | |
1da177e4 | 677 | else |
1c2bf374 | 678 | grp_goal = -1; |
1da177e4 | 679 | } else { |
1c2bf374 MC |
680 | if (grp_goal > 0) |
681 | start = grp_goal; | |
1da177e4 LT |
682 | else |
683 | start = 0; | |
684 | end = EXT3_BLOCKS_PER_GROUP(sb); | |
685 | } | |
686 | ||
687 | BUG_ON(start > EXT3_BLOCKS_PER_GROUP(sb)); | |
688 | ||
689 | repeat: | |
1c2bf374 MC |
690 | if (grp_goal < 0 || !ext3_test_allocatable(grp_goal, bitmap_bh)) { |
691 | grp_goal = find_next_usable_block(start, bitmap_bh, end); | |
692 | if (grp_goal < 0) | |
1da177e4 LT |
693 | goto fail_access; |
694 | if (!my_rsv) { | |
695 | int i; | |
696 | ||
1c2bf374 MC |
697 | for (i = 0; i < 7 && grp_goal > start && |
698 | ext3_test_allocatable(grp_goal - 1, | |
1da177e4 | 699 | bitmap_bh); |
1c2bf374 | 700 | i++, grp_goal--) |
1da177e4 LT |
701 | ; |
702 | } | |
703 | } | |
1c2bf374 | 704 | start = grp_goal; |
1da177e4 | 705 | |
1c2bf374 | 706 | if (!claim_block(sb_bgl_lock(EXT3_SB(sb), group), grp_goal, bitmap_bh)) { |
1da177e4 LT |
707 | /* |
708 | * The block was allocated by another thread, or it was | |
709 | * allocated and then freed by another thread | |
710 | */ | |
711 | start++; | |
1c2bf374 | 712 | grp_goal++; |
1da177e4 LT |
713 | if (start >= end) |
714 | goto fail_access; | |
715 | goto repeat; | |
716 | } | |
b54e41ec | 717 | num++; |
1c2bf374 MC |
718 | grp_goal++; |
719 | while (num < *count && grp_goal < end | |
720 | && ext3_test_allocatable(grp_goal, bitmap_bh) | |
721 | && claim_block(sb_bgl_lock(EXT3_SB(sb), group), grp_goal, bitmap_bh)) { | |
b54e41ec | 722 | num++; |
1c2bf374 | 723 | grp_goal++; |
b54e41ec MC |
724 | } |
725 | *count = num; | |
1c2bf374 | 726 | return grp_goal - num; |
1da177e4 | 727 | fail_access: |
b54e41ec | 728 | *count = num; |
1da177e4 LT |
729 | return -1; |
730 | } | |
731 | ||
732 | /** | |
733 | * find_next_reservable_window(): | |
734 | * find a reservable space within the given range. | |
735 | * It does not allocate the reservation window for now: | |
736 | * alloc_new_reservation() will do the work later. | |
737 | * | |
738 | * @search_head: the head of the searching list; | |
739 | * This is not necessarily the list head of the whole filesystem | |
740 | * | |
741 | * We have both head and start_block to assist the search | |
742 | * for the reservable space. The list starts from head, | |
743 | * but we will shift to the place where start_block is, | |
744 | * then start from there, when looking for a reservable space. | |
745 | * | |
746 | * @size: the target new reservation window size | |
747 | * | |
748 | * @group_first_block: the first block we consider to start | |
749 | * the real search from | |
750 | * | |
751 | * @last_block: | |
752 | * the maximum block number that our goal reservable space | |
753 | * could start from. This is normally the last block in this | |
754 | * group. The search will end when we found the start of next | |
755 | * possible reservable space is out of this boundary. | |
756 | * This could handle the cross boundary reservation window | |
757 | * request. | |
758 | * | |
759 | * basically we search from the given range, rather than the whole | |
760 | * reservation double linked list, (start_block, last_block) | |
761 | * to find a free region that is of my size and has not | |
762 | * been reserved. | |
763 | * | |
1da177e4 | 764 | */ |
21fe3471 | 765 | static int find_next_reservable_window( |
1da177e4 | 766 | struct ext3_reserve_window_node *search_head, |
21fe3471 | 767 | struct ext3_reserve_window_node *my_rsv, |
1c2bf374 MC |
768 | struct super_block * sb, |
769 | ext3_fsblk_t start_block, | |
770 | ext3_fsblk_t last_block) | |
1da177e4 LT |
771 | { |
772 | struct rb_node *next; | |
773 | struct ext3_reserve_window_node *rsv, *prev; | |
1c2bf374 | 774 | ext3_fsblk_t cur; |
21fe3471 | 775 | int size = my_rsv->rsv_goal_size; |
1da177e4 LT |
776 | |
777 | /* TODO: make the start of the reservation window byte-aligned */ | |
778 | /* cur = *start_block & ~7;*/ | |
21fe3471 | 779 | cur = start_block; |
1da177e4 LT |
780 | rsv = search_head; |
781 | if (!rsv) | |
21fe3471 | 782 | return -1; |
1da177e4 LT |
783 | |
784 | while (1) { | |
785 | if (cur <= rsv->rsv_end) | |
786 | cur = rsv->rsv_end + 1; | |
787 | ||
788 | /* TODO? | |
789 | * in the case we could not find a reservable space | |
790 | * that is what is expected, during the re-search, we could | |
791 | * remember what's the largest reservable space we could have | |
792 | * and return that one. | |
793 | * | |
794 | * For now it will fail if we could not find the reservable | |
795 | * space with expected-size (or more)... | |
796 | */ | |
797 | if (cur > last_block) | |
21fe3471 | 798 | return -1; /* fail */ |
1da177e4 LT |
799 | |
800 | prev = rsv; | |
801 | next = rb_next(&rsv->rsv_node); | |
21fe3471 | 802 | rsv = list_entry(next,struct ext3_reserve_window_node,rsv_node); |
1da177e4 LT |
803 | |
804 | /* | |
805 | * Reached the last reservation, we can just append to the | |
806 | * previous one. | |
807 | */ | |
808 | if (!next) | |
809 | break; | |
810 | ||
811 | if (cur + size <= rsv->rsv_start) { | |
812 | /* | |
813 | * Found a reserveable space big enough. We could | |
814 | * have a reservation across the group boundary here | |
815 | */ | |
816 | break; | |
817 | } | |
818 | } | |
819 | /* | |
820 | * we come here either : | |
821 | * when we reach the end of the whole list, | |
822 | * and there is empty reservable space after last entry in the list. | |
823 | * append it to the end of the list. | |
824 | * | |
825 | * or we found one reservable space in the middle of the list, | |
826 | * return the reservation window that we could append to. | |
827 | * succeed. | |
828 | */ | |
21fe3471 MC |
829 | |
830 | if ((prev != my_rsv) && (!rsv_is_empty(&my_rsv->rsv_window))) | |
831 | rsv_window_remove(sb, my_rsv); | |
832 | ||
833 | /* | |
834 | * Let's book the whole avaliable window for now. We will check the | |
835 | * disk bitmap later and then, if there are free blocks then we adjust | |
836 | * the window size if it's larger than requested. | |
837 | * Otherwise, we will remove this node from the tree next time | |
838 | * call find_next_reservable_window. | |
839 | */ | |
840 | my_rsv->rsv_start = cur; | |
841 | my_rsv->rsv_end = cur + size - 1; | |
842 | my_rsv->rsv_alloc_hit = 0; | |
843 | ||
844 | if (prev != my_rsv) | |
845 | ext3_rsv_window_add(sb, my_rsv); | |
846 | ||
847 | return 0; | |
1da177e4 LT |
848 | } |
849 | ||
850 | /** | |
851 | * alloc_new_reservation()--allocate a new reservation window | |
852 | * | |
853 | * To make a new reservation, we search part of the filesystem | |
854 | * reservation list (the list that inside the group). We try to | |
855 | * allocate a new reservation window near the allocation goal, | |
856 | * or the beginning of the group, if there is no goal. | |
857 | * | |
858 | * We first find a reservable space after the goal, then from | |
859 | * there, we check the bitmap for the first free block after | |
860 | * it. If there is no free block until the end of group, then the | |
861 | * whole group is full, we failed. Otherwise, check if the free | |
862 | * block is inside the expected reservable space, if so, we | |
863 | * succeed. | |
864 | * If the first free block is outside the reservable space, then | |
865 | * start from the first free block, we search for next available | |
866 | * space, and go on. | |
867 | * | |
868 | * on succeed, a new reservation will be found and inserted into the list | |
869 | * It contains at least one free block, and it does not overlap with other | |
870 | * reservation windows. | |
871 | * | |
872 | * failed: we failed to find a reservation window in this group | |
873 | * | |
874 | * @rsv: the reservation | |
875 | * | |
1c2bf374 | 876 | * @grp_goal: The goal (group-relative). It is where the search for a |
1da177e4 | 877 | * free reservable space should start from. |
1c2bf374 MC |
878 | * if we have a grp_goal(grp_goal >0 ), then start from there, |
879 | * no grp_goal(grp_goal = -1), we start from the first block | |
1da177e4 LT |
880 | * of the group. |
881 | * | |
882 | * @sb: the super block | |
883 | * @group: the group we are trying to allocate in | |
884 | * @bitmap_bh: the block group block bitmap | |
21fe3471 | 885 | * |
1da177e4 LT |
886 | */ |
887 | static int alloc_new_reservation(struct ext3_reserve_window_node *my_rsv, | |
1c2bf374 | 888 | ext3_grpblk_t grp_goal, struct super_block *sb, |
1da177e4 LT |
889 | unsigned int group, struct buffer_head *bitmap_bh) |
890 | { | |
891 | struct ext3_reserve_window_node *search_head; | |
1c2bf374 MC |
892 | ext3_fsblk_t group_first_block, group_end_block, start_block; |
893 | ext3_grpblk_t first_free_block; | |
1da177e4 LT |
894 | struct rb_root *fs_rsv_root = &EXT3_SB(sb)->s_rsv_window_root; |
895 | unsigned long size; | |
21fe3471 MC |
896 | int ret; |
897 | spinlock_t *rsv_lock = &EXT3_SB(sb)->s_rsv_window_lock; | |
1da177e4 | 898 | |
43d23f90 | 899 | group_first_block = ext3_group_first_block_no(sb, group); |
1da177e4 LT |
900 | group_end_block = group_first_block + EXT3_BLOCKS_PER_GROUP(sb) - 1; |
901 | ||
1c2bf374 | 902 | if (grp_goal < 0) |
1da177e4 LT |
903 | start_block = group_first_block; |
904 | else | |
1c2bf374 | 905 | start_block = grp_goal + group_first_block; |
1da177e4 LT |
906 | |
907 | size = my_rsv->rsv_goal_size; | |
21fe3471 | 908 | |
1da177e4 LT |
909 | if (!rsv_is_empty(&my_rsv->rsv_window)) { |
910 | /* | |
911 | * if the old reservation is cross group boundary | |
912 | * and if the goal is inside the old reservation window, | |
913 | * we will come here when we just failed to allocate from | |
914 | * the first part of the window. We still have another part | |
915 | * that belongs to the next group. In this case, there is no | |
916 | * point to discard our window and try to allocate a new one | |
917 | * in this group(which will fail). we should | |
918 | * keep the reservation window, just simply move on. | |
919 | * | |
920 | * Maybe we could shift the start block of the reservation | |
921 | * window to the first block of next group. | |
922 | */ | |
923 | ||
924 | if ((my_rsv->rsv_start <= group_end_block) && | |
925 | (my_rsv->rsv_end > group_end_block) && | |
926 | (start_block >= my_rsv->rsv_start)) | |
927 | return -1; | |
928 | ||
929 | if ((my_rsv->rsv_alloc_hit > | |
930 | (my_rsv->rsv_end - my_rsv->rsv_start + 1) / 2)) { | |
931 | /* | |
932 | * if we previously allocation hit ration is greater than half | |
933 | * we double the size of reservation window next time | |
934 | * otherwise keep the same | |
935 | */ | |
936 | size = size * 2; | |
937 | if (size > EXT3_MAX_RESERVE_BLOCKS) | |
938 | size = EXT3_MAX_RESERVE_BLOCKS; | |
939 | my_rsv->rsv_goal_size= size; | |
940 | } | |
941 | } | |
21fe3471 MC |
942 | |
943 | spin_lock(rsv_lock); | |
1da177e4 LT |
944 | /* |
945 | * shift the search start to the window near the goal block | |
946 | */ | |
947 | search_head = search_reserve_window(fs_rsv_root, start_block); | |
948 | ||
949 | /* | |
950 | * find_next_reservable_window() simply finds a reservable window | |
951 | * inside the given range(start_block, group_end_block). | |
952 | * | |
953 | * To make sure the reservation window has a free bit inside it, we | |
954 | * need to check the bitmap after we found a reservable window. | |
955 | */ | |
956 | retry: | |
21fe3471 MC |
957 | ret = find_next_reservable_window(search_head, my_rsv, sb, |
958 | start_block, group_end_block); | |
959 | ||
960 | if (ret == -1) { | |
961 | if (!rsv_is_empty(&my_rsv->rsv_window)) | |
962 | rsv_window_remove(sb, my_rsv); | |
963 | spin_unlock(rsv_lock); | |
964 | return -1; | |
965 | } | |
966 | ||
1da177e4 LT |
967 | /* |
968 | * On success, find_next_reservable_window() returns the | |
969 | * reservation window where there is a reservable space after it. | |
970 | * Before we reserve this reservable space, we need | |
971 | * to make sure there is at least a free block inside this region. | |
972 | * | |
973 | * searching the first free bit on the block bitmap and copy of | |
974 | * last committed bitmap alternatively, until we found a allocatable | |
975 | * block. Search start from the start block of the reservable space | |
976 | * we just found. | |
977 | */ | |
21fe3471 | 978 | spin_unlock(rsv_lock); |
1da177e4 | 979 | first_free_block = bitmap_search_next_usable_block( |
21fe3471 | 980 | my_rsv->rsv_start - group_first_block, |
1da177e4 LT |
981 | bitmap_bh, group_end_block - group_first_block + 1); |
982 | ||
983 | if (first_free_block < 0) { | |
984 | /* | |
985 | * no free block left on the bitmap, no point | |
986 | * to reserve the space. return failed. | |
987 | */ | |
21fe3471 MC |
988 | spin_lock(rsv_lock); |
989 | if (!rsv_is_empty(&my_rsv->rsv_window)) | |
990 | rsv_window_remove(sb, my_rsv); | |
991 | spin_unlock(rsv_lock); | |
992 | return -1; /* failed */ | |
1da177e4 | 993 | } |
21fe3471 | 994 | |
1da177e4 LT |
995 | start_block = first_free_block + group_first_block; |
996 | /* | |
997 | * check if the first free block is within the | |
21fe3471 | 998 | * free space we just reserved |
1da177e4 | 999 | */ |
21fe3471 MC |
1000 | if (start_block >= my_rsv->rsv_start && start_block < my_rsv->rsv_end) |
1001 | return 0; /* success */ | |
1da177e4 LT |
1002 | /* |
1003 | * if the first free bit we found is out of the reservable space | |
21fe3471 | 1004 | * continue search for next reservable space, |
1da177e4 LT |
1005 | * start from where the free block is, |
1006 | * we also shift the list head to where we stopped last time | |
1007 | */ | |
21fe3471 MC |
1008 | search_head = my_rsv; |
1009 | spin_lock(rsv_lock); | |
1da177e4 | 1010 | goto retry; |
1da177e4 LT |
1011 | } |
1012 | ||
d48589bf MC |
1013 | static void try_to_extend_reservation(struct ext3_reserve_window_node *my_rsv, |
1014 | struct super_block *sb, int size) | |
1015 | { | |
1016 | struct ext3_reserve_window_node *next_rsv; | |
1017 | struct rb_node *next; | |
1018 | spinlock_t *rsv_lock = &EXT3_SB(sb)->s_rsv_window_lock; | |
1019 | ||
1020 | if (!spin_trylock(rsv_lock)) | |
1021 | return; | |
1022 | ||
1023 | next = rb_next(&my_rsv->rsv_node); | |
1024 | ||
1025 | if (!next) | |
1026 | my_rsv->rsv_end += size; | |
1027 | else { | |
1028 | next_rsv = list_entry(next, struct ext3_reserve_window_node, rsv_node); | |
1029 | ||
1030 | if ((next_rsv->rsv_start - my_rsv->rsv_end - 1) >= size) | |
1031 | my_rsv->rsv_end += size; | |
1032 | else | |
1033 | my_rsv->rsv_end = next_rsv->rsv_start - 1; | |
1034 | } | |
1035 | spin_unlock(rsv_lock); | |
1036 | } | |
1037 | ||
1da177e4 LT |
1038 | /* |
1039 | * This is the main function used to allocate a new block and its reservation | |
1040 | * window. | |
1041 | * | |
1042 | * Each time when a new block allocation is need, first try to allocate from | |
1043 | * its own reservation. If it does not have a reservation window, instead of | |
1044 | * looking for a free bit on bitmap first, then look up the reservation list to | |
1045 | * see if it is inside somebody else's reservation window, we try to allocate a | |
1046 | * reservation window for it starting from the goal first. Then do the block | |
1047 | * allocation within the reservation window. | |
1048 | * | |
1049 | * This will avoid keeping on searching the reservation list again and | |
5b116879 | 1050 | * again when somebody is looking for a free block (without |
1da177e4 LT |
1051 | * reservation), and there are lots of free blocks, but they are all |
1052 | * being reserved. | |
1053 | * | |
1054 | * We use a sorted double linked list for the per-filesystem reservation list. | |
1055 | * The insert, remove and find a free space(non-reserved) operations for the | |
1056 | * sorted double linked list should be fast. | |
1057 | * | |
1058 | */ | |
1c2bf374 | 1059 | static ext3_grpblk_t |
1da177e4 LT |
1060 | ext3_try_to_allocate_with_rsv(struct super_block *sb, handle_t *handle, |
1061 | unsigned int group, struct buffer_head *bitmap_bh, | |
1c2bf374 MC |
1062 | ext3_grpblk_t grp_goal, |
1063 | struct ext3_reserve_window_node * my_rsv, | |
b54e41ec | 1064 | unsigned long *count, int *errp) |
1da177e4 | 1065 | { |
1c2bf374 MC |
1066 | ext3_fsblk_t group_first_block; |
1067 | ext3_grpblk_t ret = 0; | |
1da177e4 | 1068 | int fatal; |
b54e41ec | 1069 | unsigned long num = *count; |
1da177e4 LT |
1070 | |
1071 | *errp = 0; | |
1072 | ||
1073 | /* | |
1074 | * Make sure we use undo access for the bitmap, because it is critical | |
1075 | * that we do the frozen_data COW on bitmap buffers in all cases even | |
1076 | * if the buffer is in BJ_Forget state in the committing transaction. | |
1077 | */ | |
1078 | BUFFER_TRACE(bitmap_bh, "get undo access for new block"); | |
1079 | fatal = ext3_journal_get_undo_access(handle, bitmap_bh); | |
1080 | if (fatal) { | |
1081 | *errp = fatal; | |
1082 | return -1; | |
1083 | } | |
1084 | ||
1085 | /* | |
1086 | * we don't deal with reservation when | |
1087 | * filesystem is mounted without reservation | |
1088 | * or the file is not a regular file | |
1089 | * or last attempt to allocate a block with reservation turned on failed | |
1090 | */ | |
1091 | if (my_rsv == NULL ) { | |
b54e41ec | 1092 | ret = ext3_try_to_allocate(sb, handle, group, bitmap_bh, |
1c2bf374 | 1093 | grp_goal, count, NULL); |
1da177e4 LT |
1094 | goto out; |
1095 | } | |
1da177e4 | 1096 | /* |
1c2bf374 MC |
1097 | * grp_goal is a group relative block number (if there is a goal) |
1098 | * 0 < grp_goal < EXT3_BLOCKS_PER_GROUP(sb) | |
1da177e4 LT |
1099 | * first block is a filesystem wide block number |
1100 | * first block is the block number of the first block in this group | |
1101 | */ | |
43d23f90 | 1102 | group_first_block = ext3_group_first_block_no(sb, group); |
1da177e4 LT |
1103 | |
1104 | /* | |
1105 | * Basically we will allocate a new block from inode's reservation | |
1106 | * window. | |
1107 | * | |
1108 | * We need to allocate a new reservation window, if: | |
1109 | * a) inode does not have a reservation window; or | |
1110 | * b) last attempt to allocate a block from existing reservation | |
1111 | * failed; or | |
1112 | * c) we come here with a goal and with a reservation window | |
1113 | * | |
1114 | * We do not need to allocate a new reservation window if we come here | |
1115 | * at the beginning with a goal and the goal is inside the window, or | |
1116 | * we don't have a goal but already have a reservation window. | |
1117 | * then we could go to allocate from the reservation window directly. | |
1118 | */ | |
1119 | while (1) { | |
21fe3471 | 1120 | if (rsv_is_empty(&my_rsv->rsv_window) || (ret < 0) || |
1c2bf374 | 1121 | !goal_in_my_reservation(&my_rsv->rsv_window, grp_goal, group, sb)) { |
d48589bf MC |
1122 | if (my_rsv->rsv_goal_size < *count) |
1123 | my_rsv->rsv_goal_size = *count; | |
1c2bf374 | 1124 | ret = alloc_new_reservation(my_rsv, grp_goal, sb, |
1da177e4 | 1125 | group, bitmap_bh); |
1da177e4 LT |
1126 | if (ret < 0) |
1127 | break; /* failed */ | |
1128 | ||
1c2bf374 MC |
1129 | if (!goal_in_my_reservation(&my_rsv->rsv_window, grp_goal, group, sb)) |
1130 | grp_goal = -1; | |
1131 | } else if (grp_goal > 0 && (my_rsv->rsv_end-grp_goal+1) < *count) | |
d48589bf | 1132 | try_to_extend_reservation(my_rsv, sb, |
1c2bf374 | 1133 | *count-my_rsv->rsv_end + grp_goal - 1); |
d48589bf | 1134 | |
21fe3471 MC |
1135 | if ((my_rsv->rsv_start >= group_first_block + EXT3_BLOCKS_PER_GROUP(sb)) |
1136 | || (my_rsv->rsv_end < group_first_block)) | |
1da177e4 | 1137 | BUG(); |
1c2bf374 | 1138 | ret = ext3_try_to_allocate(sb, handle, group, bitmap_bh, grp_goal, |
b54e41ec | 1139 | &num, &my_rsv->rsv_window); |
1da177e4 | 1140 | if (ret >= 0) { |
b54e41ec MC |
1141 | my_rsv->rsv_alloc_hit += num; |
1142 | *count = num; | |
1da177e4 LT |
1143 | break; /* succeed */ |
1144 | } | |
b54e41ec | 1145 | num = *count; |
1da177e4 LT |
1146 | } |
1147 | out: | |
1148 | if (ret >= 0) { | |
1149 | BUFFER_TRACE(bitmap_bh, "journal_dirty_metadata for " | |
1150 | "bitmap block"); | |
1151 | fatal = ext3_journal_dirty_metadata(handle, bitmap_bh); | |
1152 | if (fatal) { | |
1153 | *errp = fatal; | |
1154 | return -1; | |
1155 | } | |
1156 | return ret; | |
1157 | } | |
1158 | ||
1159 | BUFFER_TRACE(bitmap_bh, "journal_release_buffer"); | |
1160 | ext3_journal_release_buffer(handle, bitmap_bh); | |
1161 | return ret; | |
1162 | } | |
1163 | ||
1164 | static int ext3_has_free_blocks(struct ext3_sb_info *sbi) | |
1165 | { | |
1c2bf374 | 1166 | ext3_fsblk_t free_blocks, root_blocks; |
1da177e4 LT |
1167 | |
1168 | free_blocks = percpu_counter_read_positive(&sbi->s_freeblocks_counter); | |
1169 | root_blocks = le32_to_cpu(sbi->s_es->s_r_blocks_count); | |
1170 | if (free_blocks < root_blocks + 1 && !capable(CAP_SYS_RESOURCE) && | |
1171 | sbi->s_resuid != current->fsuid && | |
1172 | (sbi->s_resgid == 0 || !in_group_p (sbi->s_resgid))) { | |
1173 | return 0; | |
1174 | } | |
1175 | return 1; | |
1176 | } | |
1177 | ||
1178 | /* | |
1179 | * ext3_should_retry_alloc() is called when ENOSPC is returned, and if | |
1180 | * it is profitable to retry the operation, this function will wait | |
1181 | * for the current or commiting transaction to complete, and then | |
1182 | * return TRUE. | |
1183 | */ | |
1184 | int ext3_should_retry_alloc(struct super_block *sb, int *retries) | |
1185 | { | |
1186 | if (!ext3_has_free_blocks(EXT3_SB(sb)) || (*retries)++ > 3) | |
1187 | return 0; | |
1188 | ||
1189 | jbd_debug(1, "%s: retrying operation after ENOSPC\n", sb->s_id); | |
1190 | ||
1191 | return journal_force_commit_nested(EXT3_SB(sb)->s_journal); | |
1192 | } | |
1193 | ||
1194 | /* | |
1195 | * ext3_new_block uses a goal block to assist allocation. If the goal is | |
1196 | * free, or there is a free block within 32 blocks of the goal, that block | |
1197 | * is allocated. Otherwise a forward search is made for a free block; within | |
1198 | * each block group the search first looks for an entire free byte in the block | |
1199 | * bitmap, and then for any free bit if that fails. | |
1200 | * This function also updates quota and i_blocks field. | |
1201 | */ | |
1c2bf374 MC |
1202 | ext3_fsblk_t ext3_new_blocks(handle_t *handle, struct inode *inode, |
1203 | ext3_fsblk_t goal, unsigned long *count, int *errp) | |
1da177e4 LT |
1204 | { |
1205 | struct buffer_head *bitmap_bh = NULL; | |
1206 | struct buffer_head *gdp_bh; | |
1207 | int group_no; | |
1208 | int goal_group; | |
1c2bf374 MC |
1209 | ext3_grpblk_t grp_target_blk; /* blockgroup relative goal block */ |
1210 | ext3_grpblk_t grp_alloc_blk; /* blockgroup-relative allocated block*/ | |
1211 | ext3_fsblk_t ret_block; /* filesyetem-wide allocated block */ | |
1da177e4 | 1212 | int bgi; /* blockgroup iteration index */ |
1da177e4 LT |
1213 | int fatal = 0, err; |
1214 | int performed_allocation = 0; | |
1c2bf374 | 1215 | ext3_grpblk_t free_blocks; /* number of free blocks in a group */ |
1da177e4 LT |
1216 | struct super_block *sb; |
1217 | struct ext3_group_desc *gdp; | |
1218 | struct ext3_super_block *es; | |
1219 | struct ext3_sb_info *sbi; | |
1220 | struct ext3_reserve_window_node *my_rsv = NULL; | |
1221 | struct ext3_block_alloc_info *block_i; | |
1222 | unsigned short windowsz = 0; | |
1223 | #ifdef EXT3FS_DEBUG | |
1224 | static int goal_hits, goal_attempts; | |
1225 | #endif | |
1226 | unsigned long ngroups; | |
b54e41ec | 1227 | unsigned long num = *count; |
1da177e4 LT |
1228 | |
1229 | *errp = -ENOSPC; | |
1230 | sb = inode->i_sb; | |
1231 | if (!sb) { | |
1232 | printk("ext3_new_block: nonexistent device"); | |
1233 | return 0; | |
1234 | } | |
1235 | ||
1236 | /* | |
1237 | * Check quota for allocation of this block. | |
1238 | */ | |
faa56976 | 1239 | if (DQUOT_ALLOC_BLOCK(inode, num)) { |
1da177e4 LT |
1240 | *errp = -EDQUOT; |
1241 | return 0; | |
1242 | } | |
1243 | ||
1244 | sbi = EXT3_SB(sb); | |
1245 | es = EXT3_SB(sb)->s_es; | |
1246 | ext3_debug("goal=%lu.\n", goal); | |
1247 | /* | |
1248 | * Allocate a block from reservation only when | |
1249 | * filesystem is mounted with reservation(default,-o reservation), and | |
1250 | * it's a regular file, and | |
1251 | * the desired window size is greater than 0 (One could use ioctl | |
1252 | * command EXT3_IOC_SETRSVSZ to set the window size to 0 to turn off | |
1253 | * reservation on that particular file) | |
1254 | */ | |
1255 | block_i = EXT3_I(inode)->i_block_alloc_info; | |
1256 | if (block_i && ((windowsz = block_i->rsv_window_node.rsv_goal_size) > 0)) | |
1257 | my_rsv = &block_i->rsv_window_node; | |
1258 | ||
1259 | if (!ext3_has_free_blocks(sbi)) { | |
1260 | *errp = -ENOSPC; | |
1261 | goto out; | |
1262 | } | |
1263 | ||
1264 | /* | |
1265 | * First, test whether the goal block is free. | |
1266 | */ | |
1267 | if (goal < le32_to_cpu(es->s_first_data_block) || | |
1268 | goal >= le32_to_cpu(es->s_blocks_count)) | |
1269 | goal = le32_to_cpu(es->s_first_data_block); | |
1270 | group_no = (goal - le32_to_cpu(es->s_first_data_block)) / | |
1271 | EXT3_BLOCKS_PER_GROUP(sb); | |
1272 | gdp = ext3_get_group_desc(sb, group_no, &gdp_bh); | |
1273 | if (!gdp) | |
1274 | goto io_error; | |
1275 | ||
1276 | goal_group = group_no; | |
1277 | retry: | |
1278 | free_blocks = le16_to_cpu(gdp->bg_free_blocks_count); | |
1279 | /* | |
1280 | * if there is not enough free blocks to make a new resevation | |
1281 | * turn off reservation for this allocation | |
1282 | */ | |
1283 | if (my_rsv && (free_blocks < windowsz) | |
1284 | && (rsv_is_empty(&my_rsv->rsv_window))) | |
1285 | my_rsv = NULL; | |
1286 | ||
1287 | if (free_blocks > 0) { | |
1c2bf374 | 1288 | grp_target_blk = ((goal - le32_to_cpu(es->s_first_data_block)) % |
1da177e4 LT |
1289 | EXT3_BLOCKS_PER_GROUP(sb)); |
1290 | bitmap_bh = read_block_bitmap(sb, group_no); | |
1291 | if (!bitmap_bh) | |
1292 | goto io_error; | |
1c2bf374 MC |
1293 | grp_alloc_blk = ext3_try_to_allocate_with_rsv(sb, handle, |
1294 | group_no, bitmap_bh, grp_target_blk, | |
1295 | my_rsv, &num, &fatal); | |
1da177e4 LT |
1296 | if (fatal) |
1297 | goto out; | |
1c2bf374 | 1298 | if (grp_alloc_blk >= 0) |
1da177e4 LT |
1299 | goto allocated; |
1300 | } | |
1301 | ||
1302 | ngroups = EXT3_SB(sb)->s_groups_count; | |
1303 | smp_rmb(); | |
1304 | ||
1305 | /* | |
1306 | * Now search the rest of the groups. We assume that | |
1307 | * i and gdp correctly point to the last group visited. | |
1308 | */ | |
1309 | for (bgi = 0; bgi < ngroups; bgi++) { | |
1310 | group_no++; | |
1311 | if (group_no >= ngroups) | |
1312 | group_no = 0; | |
1313 | gdp = ext3_get_group_desc(sb, group_no, &gdp_bh); | |
1314 | if (!gdp) { | |
1315 | *errp = -EIO; | |
1316 | goto out; | |
1317 | } | |
1318 | free_blocks = le16_to_cpu(gdp->bg_free_blocks_count); | |
1319 | /* | |
1320 | * skip this group if the number of | |
1321 | * free blocks is less than half of the reservation | |
1322 | * window size. | |
1323 | */ | |
1324 | if (free_blocks <= (windowsz/2)) | |
1325 | continue; | |
1326 | ||
1327 | brelse(bitmap_bh); | |
1328 | bitmap_bh = read_block_bitmap(sb, group_no); | |
1329 | if (!bitmap_bh) | |
1330 | goto io_error; | |
1c2bf374 MC |
1331 | /* |
1332 | * try to allocate block(s) from this group, without a goal(-1). | |
1333 | */ | |
1334 | grp_alloc_blk = ext3_try_to_allocate_with_rsv(sb, handle, | |
1335 | group_no, bitmap_bh, -1, my_rsv, | |
1336 | &num, &fatal); | |
1da177e4 LT |
1337 | if (fatal) |
1338 | goto out; | |
1c2bf374 | 1339 | if (grp_alloc_blk >= 0) |
1da177e4 LT |
1340 | goto allocated; |
1341 | } | |
1342 | /* | |
1343 | * We may end up a bogus ealier ENOSPC error due to | |
1344 | * filesystem is "full" of reservations, but | |
1345 | * there maybe indeed free blocks avaliable on disk | |
1346 | * In this case, we just forget about the reservations | |
1347 | * just do block allocation as without reservations. | |
1348 | */ | |
1349 | if (my_rsv) { | |
1350 | my_rsv = NULL; | |
1351 | group_no = goal_group; | |
1352 | goto retry; | |
1353 | } | |
1354 | /* No space left on the device */ | |
1355 | *errp = -ENOSPC; | |
1356 | goto out; | |
1357 | ||
1358 | allocated: | |
1359 | ||
1360 | ext3_debug("using block group %d(%d)\n", | |
1361 | group_no, gdp->bg_free_blocks_count); | |
1362 | ||
1363 | BUFFER_TRACE(gdp_bh, "get_write_access"); | |
1364 | fatal = ext3_journal_get_write_access(handle, gdp_bh); | |
1365 | if (fatal) | |
1366 | goto out; | |
1367 | ||
43d23f90 | 1368 | ret_block = grp_alloc_blk + ext3_group_first_block_no(sb, group_no); |
1da177e4 | 1369 | |
1c2bf374 MC |
1370 | if (in_range(le32_to_cpu(gdp->bg_block_bitmap), ret_block, num) || |
1371 | in_range(le32_to_cpu(gdp->bg_inode_bitmap), ret_block, num) || | |
1372 | in_range(ret_block, le32_to_cpu(gdp->bg_inode_table), | |
faa56976 | 1373 | EXT3_SB(sb)->s_itb_per_group) || |
1c2bf374 | 1374 | in_range(ret_block + num - 1, le32_to_cpu(gdp->bg_inode_table), |
1da177e4 LT |
1375 | EXT3_SB(sb)->s_itb_per_group)) |
1376 | ext3_error(sb, "ext3_new_block", | |
1377 | "Allocating block in system zone - " | |
1c2bf374 MC |
1378 | "blocks from "E3FSBLK", length %lu", |
1379 | ret_block, num); | |
1da177e4 LT |
1380 | |
1381 | performed_allocation = 1; | |
1382 | ||
1383 | #ifdef CONFIG_JBD_DEBUG | |
1384 | { | |
1385 | struct buffer_head *debug_bh; | |
1386 | ||
1387 | /* Record bitmap buffer state in the newly allocated block */ | |
1c2bf374 | 1388 | debug_bh = sb_find_get_block(sb, ret_block); |
1da177e4 LT |
1389 | if (debug_bh) { |
1390 | BUFFER_TRACE(debug_bh, "state when allocated"); | |
1391 | BUFFER_TRACE2(debug_bh, bitmap_bh, "bitmap state"); | |
1392 | brelse(debug_bh); | |
1393 | } | |
1394 | } | |
1395 | jbd_lock_bh_state(bitmap_bh); | |
1396 | spin_lock(sb_bgl_lock(sbi, group_no)); | |
1397 | if (buffer_jbd(bitmap_bh) && bh2jh(bitmap_bh)->b_committed_data) { | |
faa56976 MC |
1398 | int i; |
1399 | ||
1400 | for (i = 0; i < num; i++) { | |
1c2bf374 | 1401 | if (ext3_test_bit(grp_alloc_blk+i, |
faa56976 MC |
1402 | bh2jh(bitmap_bh)->b_committed_data)) { |
1403 | printk("%s: block was unexpectedly set in " | |
1404 | "b_committed_data\n", __FUNCTION__); | |
1405 | } | |
1da177e4 LT |
1406 | } |
1407 | } | |
1c2bf374 | 1408 | ext3_debug("found bit %d\n", grp_alloc_blk); |
1da177e4 LT |
1409 | spin_unlock(sb_bgl_lock(sbi, group_no)); |
1410 | jbd_unlock_bh_state(bitmap_bh); | |
1411 | #endif | |
1412 | ||
faa56976 | 1413 | if (ret_block + num - 1 >= le32_to_cpu(es->s_blocks_count)) { |
1da177e4 | 1414 | ext3_error(sb, "ext3_new_block", |
1c2bf374 | 1415 | "block("E3FSBLK") >= blocks count(%d) - " |
1da177e4 LT |
1416 | "block_group = %d, es == %p ", ret_block, |
1417 | le32_to_cpu(es->s_blocks_count), group_no, es); | |
1418 | goto out; | |
1419 | } | |
1420 | ||
1421 | /* | |
1422 | * It is up to the caller to add the new buffer to a journal | |
1423 | * list of some description. We don't know in advance whether | |
1424 | * the caller wants to use it as metadata or data. | |
1425 | */ | |
1c2bf374 | 1426 | ext3_debug("allocating block %lu. Goal hits %d of %d.\n", |
1da177e4 LT |
1427 | ret_block, goal_hits, goal_attempts); |
1428 | ||
1429 | spin_lock(sb_bgl_lock(sbi, group_no)); | |
1430 | gdp->bg_free_blocks_count = | |
faa56976 | 1431 | cpu_to_le16(le16_to_cpu(gdp->bg_free_blocks_count) - num); |
1da177e4 | 1432 | spin_unlock(sb_bgl_lock(sbi, group_no)); |
faa56976 | 1433 | percpu_counter_mod(&sbi->s_freeblocks_counter, -num); |
1da177e4 LT |
1434 | |
1435 | BUFFER_TRACE(gdp_bh, "journal_dirty_metadata for group descriptor"); | |
1436 | err = ext3_journal_dirty_metadata(handle, gdp_bh); | |
1437 | if (!fatal) | |
1438 | fatal = err; | |
1439 | ||
1440 | sb->s_dirt = 1; | |
1441 | if (fatal) | |
1442 | goto out; | |
1443 | ||
1444 | *errp = 0; | |
1445 | brelse(bitmap_bh); | |
faa56976 | 1446 | DQUOT_FREE_BLOCK(inode, *count-num); |
b54e41ec | 1447 | *count = num; |
1da177e4 LT |
1448 | return ret_block; |
1449 | ||
1450 | io_error: | |
1451 | *errp = -EIO; | |
1452 | out: | |
1453 | if (fatal) { | |
1454 | *errp = fatal; | |
1455 | ext3_std_error(sb, fatal); | |
1456 | } | |
1457 | /* | |
1458 | * Undo the block allocation | |
1459 | */ | |
1460 | if (!performed_allocation) | |
faa56976 | 1461 | DQUOT_FREE_BLOCK(inode, *count); |
1da177e4 LT |
1462 | brelse(bitmap_bh); |
1463 | return 0; | |
1464 | } | |
1465 | ||
1c2bf374 MC |
1466 | ext3_fsblk_t ext3_new_block(handle_t *handle, struct inode *inode, |
1467 | ext3_fsblk_t goal, int *errp) | |
b54e41ec MC |
1468 | { |
1469 | unsigned long count = 1; | |
1470 | ||
1471 | return ext3_new_blocks(handle, inode, goal, &count, errp); | |
1472 | } | |
1473 | ||
43d23f90 | 1474 | ext3_fsblk_t ext3_count_free_blocks(struct super_block *sb) |
1da177e4 | 1475 | { |
43d23f90 | 1476 | ext3_fsblk_t desc_count; |
1da177e4 LT |
1477 | struct ext3_group_desc *gdp; |
1478 | int i; | |
8bdac5d1 | 1479 | unsigned long ngroups = EXT3_SB(sb)->s_groups_count; |
1da177e4 LT |
1480 | #ifdef EXT3FS_DEBUG |
1481 | struct ext3_super_block *es; | |
43d23f90 MC |
1482 | ext3_fsblk_t bitmap_count; |
1483 | unsigned long x; | |
1da177e4 LT |
1484 | struct buffer_head *bitmap_bh = NULL; |
1485 | ||
1da177e4 LT |
1486 | es = EXT3_SB(sb)->s_es; |
1487 | desc_count = 0; | |
1488 | bitmap_count = 0; | |
1489 | gdp = NULL; | |
8bdac5d1 | 1490 | |
5b116879 | 1491 | smp_rmb(); |
8bdac5d1 | 1492 | for (i = 0; i < ngroups; i++) { |
1da177e4 LT |
1493 | gdp = ext3_get_group_desc(sb, i, NULL); |
1494 | if (!gdp) | |
1495 | continue; | |
1496 | desc_count += le16_to_cpu(gdp->bg_free_blocks_count); | |
1497 | brelse(bitmap_bh); | |
1498 | bitmap_bh = read_block_bitmap(sb, i); | |
1499 | if (bitmap_bh == NULL) | |
1500 | continue; | |
1501 | ||
1502 | x = ext3_count_free(bitmap_bh, sb->s_blocksize); | |
1503 | printk("group %d: stored = %d, counted = %lu\n", | |
1504 | i, le16_to_cpu(gdp->bg_free_blocks_count), x); | |
1505 | bitmap_count += x; | |
1506 | } | |
1507 | brelse(bitmap_bh); | |
43d23f90 MC |
1508 | printk("ext3_count_free_blocks: stored = "E3FSBLK |
1509 | ", computed = "E3FSBLK", "E3FSBLK"\n", | |
1510 | le32_to_cpu(es->s_free_blocks_count), | |
1511 | desc_count, bitmap_count); | |
1da177e4 LT |
1512 | return bitmap_count; |
1513 | #else | |
1514 | desc_count = 0; | |
1da177e4 LT |
1515 | smp_rmb(); |
1516 | for (i = 0; i < ngroups; i++) { | |
1517 | gdp = ext3_get_group_desc(sb, i, NULL); | |
1518 | if (!gdp) | |
1519 | continue; | |
1520 | desc_count += le16_to_cpu(gdp->bg_free_blocks_count); | |
1521 | } | |
1522 | ||
1523 | return desc_count; | |
1524 | #endif | |
1525 | } | |
1526 | ||
1527 | static inline int | |
1c2bf374 | 1528 | block_in_use(ext3_fsblk_t block, struct super_block *sb, unsigned char *map) |
1da177e4 LT |
1529 | { |
1530 | return ext3_test_bit ((block - | |
1531 | le32_to_cpu(EXT3_SB(sb)->s_es->s_first_data_block)) % | |
1532 | EXT3_BLOCKS_PER_GROUP(sb), map); | |
1533 | } | |
1534 | ||
1535 | static inline int test_root(int a, int b) | |
1536 | { | |
1537 | int num = b; | |
1538 | ||
1539 | while (a > num) | |
1540 | num *= b; | |
1541 | return num == a; | |
1542 | } | |
1543 | ||
1544 | static int ext3_group_sparse(int group) | |
1545 | { | |
1546 | if (group <= 1) | |
1547 | return 1; | |
1548 | if (!(group & 1)) | |
1549 | return 0; | |
1550 | return (test_root(group, 7) || test_root(group, 5) || | |
1551 | test_root(group, 3)); | |
1552 | } | |
1553 | ||
1554 | /** | |
1555 | * ext3_bg_has_super - number of blocks used by the superblock in group | |
1556 | * @sb: superblock for filesystem | |
1557 | * @group: group number to check | |
1558 | * | |
1559 | * Return the number of blocks used by the superblock (primary or backup) | |
1560 | * in this group. Currently this will be only 0 or 1. | |
1561 | */ | |
1562 | int ext3_bg_has_super(struct super_block *sb, int group) | |
1563 | { | |
b5a7c4f5 GOC |
1564 | if (EXT3_HAS_RO_COMPAT_FEATURE(sb, |
1565 | EXT3_FEATURE_RO_COMPAT_SPARSE_SUPER) && | |
1566 | !ext3_group_sparse(group)) | |
1da177e4 LT |
1567 | return 0; |
1568 | return 1; | |
1569 | } | |
1570 | ||
b5a7c4f5 GOC |
1571 | static unsigned long ext3_bg_num_gdb_meta(struct super_block *sb, int group) |
1572 | { | |
1573 | unsigned long metagroup = group / EXT3_DESC_PER_BLOCK(sb); | |
1574 | unsigned long first = metagroup * EXT3_DESC_PER_BLOCK(sb); | |
1575 | unsigned long last = first + EXT3_DESC_PER_BLOCK(sb) - 1; | |
1576 | ||
1577 | if (group == first || group == first + 1 || group == last) | |
1578 | return 1; | |
1579 | return 0; | |
1580 | } | |
1581 | ||
1582 | static unsigned long ext3_bg_num_gdb_nometa(struct super_block *sb, int group) | |
1583 | { | |
1584 | if (EXT3_HAS_RO_COMPAT_FEATURE(sb, | |
1585 | EXT3_FEATURE_RO_COMPAT_SPARSE_SUPER) && | |
1586 | !ext3_group_sparse(group)) | |
1587 | return 0; | |
1588 | return EXT3_SB(sb)->s_gdb_count; | |
1589 | } | |
1590 | ||
1da177e4 LT |
1591 | /** |
1592 | * ext3_bg_num_gdb - number of blocks used by the group table in group | |
1593 | * @sb: superblock for filesystem | |
1594 | * @group: group number to check | |
1595 | * | |
1596 | * Return the number of blocks used by the group descriptor table | |
1597 | * (primary or backup) in this group. In the future there may be a | |
1598 | * different number of descriptor blocks in each group. | |
1599 | */ | |
1600 | unsigned long ext3_bg_num_gdb(struct super_block *sb, int group) | |
1601 | { | |
b5a7c4f5 GOC |
1602 | unsigned long first_meta_bg = |
1603 | le32_to_cpu(EXT3_SB(sb)->s_es->s_first_meta_bg); | |
1604 | unsigned long metagroup = group / EXT3_DESC_PER_BLOCK(sb); | |
1605 | ||
1606 | if (!EXT3_HAS_INCOMPAT_FEATURE(sb,EXT3_FEATURE_INCOMPAT_META_BG) || | |
1607 | metagroup < first_meta_bg) | |
1608 | return ext3_bg_num_gdb_nometa(sb,group); | |
1da177e4 | 1609 | |
b5a7c4f5 GOC |
1610 | return ext3_bg_num_gdb_meta(sb,group); |
1611 | ||
1612 | } |