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diff --git a/fs/ext3/balloc.c b/fs/ext3/balloc.c
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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
14#include <linux/config.h>
15#include <linux/time.h>
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
41struct 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 */
82static struct buffer_head *
83read_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));
97error_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
115static 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
122restart:
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
164static int
165goal_in_my_reservation(struct ext3_reserve_window *rsv, int goal,
166 unsigned int group, struct super_block * sb)
167{
168 unsigned long group_first_block, group_last_block;
169
170 group_first_block = le32_to_cpu(EXT3_SB(sb)->s_es->s_first_data_block) +
171 group * EXT3_BLOCKS_PER_GROUP(sb);
172 group_last_block = group_first_block + EXT3_BLOCKS_PER_GROUP(sb) - 1;
173
174 if ((rsv->_rsv_start > group_last_block) ||
175 (rsv->_rsv_end < group_first_block))
176 return 0;
177 if ((goal >= 0) && ((goal + group_first_block < rsv->_rsv_start)
178 || (goal + group_first_block > rsv->_rsv_end)))
179 return 0;
180 return 1;
181}
182
183/*
184 * Find the reserved window which includes the goal, or the previous one
185 * if the goal is not in any window.
186 * Returns NULL if there are no windows or if all windows start after the goal.
187 */
188static struct ext3_reserve_window_node *
189search_reserve_window(struct rb_root *root, unsigned long goal)
190{
191 struct rb_node *n = root->rb_node;
192 struct ext3_reserve_window_node *rsv;
193
194 if (!n)
195 return NULL;
196
197 do {
198 rsv = rb_entry(n, struct ext3_reserve_window_node, rsv_node);
199
200 if (goal < rsv->rsv_start)
201 n = n->rb_left;
202 else if (goal > rsv->rsv_end)
203 n = n->rb_right;
204 else
205 return rsv;
206 } while (n);
207 /*
208 * We've fallen off the end of the tree: the goal wasn't inside
209 * any particular node. OK, the previous node must be to one
210 * side of the interval containing the goal. If it's the RHS,
211 * we need to back up one.
212 */
213 if (rsv->rsv_start > goal) {
214 n = rb_prev(&rsv->rsv_node);
215 rsv = rb_entry(n, struct ext3_reserve_window_node, rsv_node);
216 }
217 return rsv;
218}
219
220void ext3_rsv_window_add(struct super_block *sb,
221 struct ext3_reserve_window_node *rsv)
222{
223 struct rb_root *root = &EXT3_SB(sb)->s_rsv_window_root;
224 struct rb_node *node = &rsv->rsv_node;
225 unsigned int start = rsv->rsv_start;
226
227 struct rb_node ** p = &root->rb_node;
228 struct rb_node * parent = NULL;
229 struct ext3_reserve_window_node *this;
230
231 while (*p)
232 {
233 parent = *p;
234 this = rb_entry(parent, struct ext3_reserve_window_node, rsv_node);
235
236 if (start < this->rsv_start)
237 p = &(*p)->rb_left;
238 else if (start > this->rsv_end)
239 p = &(*p)->rb_right;
240 else
241 BUG();
242 }
243
244 rb_link_node(node, parent, p);
245 rb_insert_color(node, root);
246}
247
248static void rsv_window_remove(struct super_block *sb,
249 struct ext3_reserve_window_node *rsv)
250{
251 rsv->rsv_start = EXT3_RESERVE_WINDOW_NOT_ALLOCATED;
252 rsv->rsv_end = EXT3_RESERVE_WINDOW_NOT_ALLOCATED;
253 rsv->rsv_alloc_hit = 0;
254 rb_erase(&rsv->rsv_node, &EXT3_SB(sb)->s_rsv_window_root);
255}
256
257static inline int rsv_is_empty(struct ext3_reserve_window *rsv)
258{
259 /* a valid reservation end block could not be 0 */
260 return (rsv->_rsv_end == EXT3_RESERVE_WINDOW_NOT_ALLOCATED);
261}
262void ext3_init_block_alloc_info(struct inode *inode)
263{
264 struct ext3_inode_info *ei = EXT3_I(inode);
265 struct ext3_block_alloc_info *block_i = ei->i_block_alloc_info;
266 struct super_block *sb = inode->i_sb;
267
268 block_i = kmalloc(sizeof(*block_i), GFP_NOFS);
269 if (block_i) {
270 struct ext3_reserve_window_node *rsv = &block_i->rsv_window_node;
271
272 rsv->rsv_start = EXT3_RESERVE_WINDOW_NOT_ALLOCATED;
273 rsv->rsv_end = EXT3_RESERVE_WINDOW_NOT_ALLOCATED;
274
275 /*
276 * if filesystem is mounted with NORESERVATION, the goal
277 * reservation window size is set to zero to indicate
278 * block reservation is off
279 */
280 if (!test_opt(sb, RESERVATION))
281 rsv->rsv_goal_size = 0;
282 else
283 rsv->rsv_goal_size = EXT3_DEFAULT_RESERVE_BLOCKS;
284 rsv->rsv_alloc_hit = 0;
285 block_i->last_alloc_logical_block = 0;
286 block_i->last_alloc_physical_block = 0;
287 }
288 ei->i_block_alloc_info = block_i;
289}
290
291void ext3_discard_reservation(struct inode *inode)
292{
293 struct ext3_inode_info *ei = EXT3_I(inode);
294 struct ext3_block_alloc_info *block_i = ei->i_block_alloc_info;
295 struct ext3_reserve_window_node *rsv;
296 spinlock_t *rsv_lock = &EXT3_SB(inode->i_sb)->s_rsv_window_lock;
297
298 if (!block_i)
299 return;
300
301 rsv = &block_i->rsv_window_node;
302 if (!rsv_is_empty(&rsv->rsv_window)) {
303 spin_lock(rsv_lock);
304 if (!rsv_is_empty(&rsv->rsv_window))
305 rsv_window_remove(inode->i_sb, rsv);
306 spin_unlock(rsv_lock);
307 }
308}
309
310/* Free given blocks, update quota and i_blocks field */
311void ext3_free_blocks_sb(handle_t *handle, struct super_block *sb,
312 unsigned long block, unsigned long count,
313 int *pdquot_freed_blocks)
314{
315 struct buffer_head *bitmap_bh = NULL;
316 struct buffer_head *gd_bh;
317 unsigned long block_group;
318 unsigned long bit;
319 unsigned long i;
320 unsigned long overflow;
321 struct ext3_group_desc * desc;
322 struct ext3_super_block * es;
323 struct ext3_sb_info *sbi;
324 int err = 0, ret;
325 unsigned group_freed;
326
327 *pdquot_freed_blocks = 0;
328 sbi = EXT3_SB(sb);
329 es = sbi->s_es;
330 if (block < le32_to_cpu(es->s_first_data_block) ||
331 block + count < block ||
332 block + count > le32_to_cpu(es->s_blocks_count)) {
333 ext3_error (sb, "ext3_free_blocks",
334 "Freeing blocks not in datazone - "
335 "block = %lu, count = %lu", block, count);
336 goto error_return;
337 }
338
339 ext3_debug ("freeing block(s) %lu-%lu\n", block, block + count - 1);
340
341do_more:
342 overflow = 0;
343 block_group = (block - le32_to_cpu(es->s_first_data_block)) /
344 EXT3_BLOCKS_PER_GROUP(sb);
345 bit = (block - le32_to_cpu(es->s_first_data_block)) %
346 EXT3_BLOCKS_PER_GROUP(sb);
347 /*
348 * Check to see if we are freeing blocks across a group
349 * boundary.
350 */
351 if (bit + count > EXT3_BLOCKS_PER_GROUP(sb)) {
352 overflow = bit + count - EXT3_BLOCKS_PER_GROUP(sb);
353 count -= overflow;
354 }
355 brelse(bitmap_bh);
356 bitmap_bh = read_block_bitmap(sb, block_group);
357 if (!bitmap_bh)
358 goto error_return;
359 desc = ext3_get_group_desc (sb, block_group, &gd_bh);
360 if (!desc)
361 goto error_return;
362
363 if (in_range (le32_to_cpu(desc->bg_block_bitmap), block, count) ||
364 in_range (le32_to_cpu(desc->bg_inode_bitmap), block, count) ||
365 in_range (block, le32_to_cpu(desc->bg_inode_table),
366 sbi->s_itb_per_group) ||
367 in_range (block + count - 1, le32_to_cpu(desc->bg_inode_table),
368 sbi->s_itb_per_group))
369 ext3_error (sb, "ext3_free_blocks",
370 "Freeing blocks in system zones - "
371 "Block = %lu, count = %lu",
372 block, count);
373
374 /*
375 * We are about to start releasing blocks in the bitmap,
376 * so we need undo access.
377 */
378 /* @@@ check errors */
379 BUFFER_TRACE(bitmap_bh, "getting undo access");
380 err = ext3_journal_get_undo_access(handle, bitmap_bh);
381 if (err)
382 goto error_return;
383
384 /*
385 * We are about to modify some metadata. Call the journal APIs
386 * to unshare ->b_data if a currently-committing transaction is
387 * using it
388 */
389 BUFFER_TRACE(gd_bh, "get_write_access");
390 err = ext3_journal_get_write_access(handle, gd_bh);
391 if (err)
392 goto error_return;
393
394 jbd_lock_bh_state(bitmap_bh);
395
396 for (i = 0, group_freed = 0; i < count; i++) {
397 /*
398 * An HJ special. This is expensive...
399 */
400#ifdef CONFIG_JBD_DEBUG
401 jbd_unlock_bh_state(bitmap_bh);
402 {
403 struct buffer_head *debug_bh;
404 debug_bh = sb_find_get_block(sb, block + i);
405 if (debug_bh) {
406 BUFFER_TRACE(debug_bh, "Deleted!");
407 if (!bh2jh(bitmap_bh)->b_committed_data)
408 BUFFER_TRACE(debug_bh,
409 "No commited data in bitmap");
410 BUFFER_TRACE2(debug_bh, bitmap_bh, "bitmap");
411 __brelse(debug_bh);
412 }
413 }
414 jbd_lock_bh_state(bitmap_bh);
415#endif
416 if (need_resched()) {
417 jbd_unlock_bh_state(bitmap_bh);
418 cond_resched();
419 jbd_lock_bh_state(bitmap_bh);
420 }
421 /* @@@ This prevents newly-allocated data from being
422 * freed and then reallocated within the same
423 * transaction.
424 *
425 * Ideally we would want to allow that to happen, but to
426 * do so requires making journal_forget() capable of
427 * revoking the queued write of a data block, which
428 * implies blocking on the journal lock. *forget()
429 * cannot block due to truncate races.
430 *
431 * Eventually we can fix this by making journal_forget()
432 * return a status indicating whether or not it was able
433 * to revoke the buffer. On successful revoke, it is
434 * safe not to set the allocation bit in the committed
435 * bitmap, because we know that there is no outstanding
436 * activity on the buffer any more and so it is safe to
437 * reallocate it.
438 */
439 BUFFER_TRACE(bitmap_bh, "set in b_committed_data");
440 J_ASSERT_BH(bitmap_bh,
441 bh2jh(bitmap_bh)->b_committed_data != NULL);
442 ext3_set_bit_atomic(sb_bgl_lock(sbi, block_group), bit + i,
443 bh2jh(bitmap_bh)->b_committed_data);
444
445 /*
446 * We clear the bit in the bitmap after setting the committed
447 * data bit, because this is the reverse order to that which
448 * the allocator uses.
449 */
450 BUFFER_TRACE(bitmap_bh, "clear bit");
451 if (!ext3_clear_bit_atomic(sb_bgl_lock(sbi, block_group),
452 bit + i, bitmap_bh->b_data)) {
453 jbd_unlock_bh_state(bitmap_bh);
454 ext3_error(sb, __FUNCTION__,
455 "bit already cleared for block %lu", block + i);
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;
487error_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 */
494void ext3_free_blocks(handle_t *handle, struct inode *inode,
495 unsigned long block, unsigned long count)
496{
497 struct super_block * sb;
498 int dquot_freed_blocks;
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 */
527static int ext3_test_allocatable(int nr, struct buffer_head *bh)
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
544static int
545bitmap_search_next_usable_block(int start, struct buffer_head *bh,
546 int maxblocks)
547{
548 int next;
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 */
578static int
579find_next_usable_block(int start, struct buffer_head *bh, int maxblocks)
580{
581 int here, next;
582 char *p, *r;
583
584 if (start > 0) {
585 /*
586 * The goal was occupied; search forward for a free
587 * block within the next XX blocks.
588 *
589 * end_goal is more or less random, but it has to be
590 * less than EXT3_BLOCKS_PER_GROUP. Aligning up to the
591 * next 64-bit boundary is simple..
592 */
593 int end_goal = (start + 63) & ~63;
594 if (end_goal > maxblocks)
595 end_goal = maxblocks;
596 here = ext3_find_next_zero_bit(bh->b_data, end_goal, start);
597 if (here < end_goal && ext3_test_allocatable(here, bh))
598 return here;
599 ext3_debug("Bit not found near goal\n");
600 }
601
602 here = start;
603 if (here < 0)
604 here = 0;
605
606 p = ((char *)bh->b_data) + (here >> 3);
607 r = memscan(p, 0, (maxblocks - here + 7) >> 3);
608 next = (r - ((char *)bh->b_data)) << 3;
609
610 if (next < maxblocks && next >= start && ext3_test_allocatable(next, bh))
611 return next;
612
613 /*
614 * The bitmap search --- search forward alternately through the actual
615 * bitmap and the last-committed copy until we find a bit free in
616 * both
617 */
618 here = bitmap_search_next_usable_block(here, bh, maxblocks);
619 return here;
620}
621
622/*
623 * We think we can allocate this block in this bitmap. Try to set the bit.
624 * If that succeeds then check that nobody has allocated and then freed the
625 * block since we saw that is was not marked in b_committed_data. If it _was_
626 * allocated and freed then clear the bit in the bitmap again and return
627 * zero (failure).
628 */
629static inline int
630claim_block(spinlock_t *lock, int block, struct buffer_head *bh)
631{
632 struct journal_head *jh = bh2jh(bh);
633 int ret;
634
635 if (ext3_set_bit_atomic(lock, block, bh->b_data))
636 return 0;
637 jbd_lock_bh_state(bh);
638 if (jh->b_committed_data && ext3_test_bit(block,jh->b_committed_data)) {
639 ext3_clear_bit_atomic(lock, block, bh->b_data);
640 ret = 0;
641 } else {
642 ret = 1;
643 }
644 jbd_unlock_bh_state(bh);
645 return ret;
646}
647
648/*
649 * If we failed to allocate the desired block then we may end up crossing to a
650 * new bitmap. In that case we must release write access to the old one via
651 * ext3_journal_release_buffer(), else we'll run out of credits.
652 */
653static int
654ext3_try_to_allocate(struct super_block *sb, handle_t *handle, int group,
655 struct buffer_head *bitmap_bh, int goal, struct ext3_reserve_window *my_rsv)
656{
657 int group_first_block, start, end;
658
659 /* we do allocation within the reservation window if we have a window */
660 if (my_rsv) {
661 group_first_block =
662 le32_to_cpu(EXT3_SB(sb)->s_es->s_first_data_block) +
663 group * EXT3_BLOCKS_PER_GROUP(sb);
664 if (my_rsv->_rsv_start >= group_first_block)
665 start = my_rsv->_rsv_start - group_first_block;
666 else
667 /* reservation window cross group boundary */
668 start = 0;
669 end = my_rsv->_rsv_end - group_first_block + 1;
670 if (end > EXT3_BLOCKS_PER_GROUP(sb))
671 /* reservation window crosses group boundary */
672 end = EXT3_BLOCKS_PER_GROUP(sb);
673 if ((start <= goal) && (goal < end))
674 start = goal;
675 else
676 goal = -1;
677 } else {
678 if (goal > 0)
679 start = goal;
680 else
681 start = 0;
682 end = EXT3_BLOCKS_PER_GROUP(sb);
683 }
684
685 BUG_ON(start > EXT3_BLOCKS_PER_GROUP(sb));
686
687repeat:
688 if (goal < 0 || !ext3_test_allocatable(goal, bitmap_bh)) {
689 goal = find_next_usable_block(start, bitmap_bh, end);
690 if (goal < 0)
691 goto fail_access;
692 if (!my_rsv) {
693 int i;
694
695 for (i = 0; i < 7 && goal > start &&
696 ext3_test_allocatable(goal - 1,
697 bitmap_bh);
698 i++, goal--)
699 ;
700 }
701 }
702 start = goal;
703
704 if (!claim_block(sb_bgl_lock(EXT3_SB(sb), group), goal, bitmap_bh)) {
705 /*
706 * The block was allocated by another thread, or it was
707 * allocated and then freed by another thread
708 */
709 start++;
710 goal++;
711 if (start >= end)
712 goto fail_access;
713 goto repeat;
714 }
715 return goal;
716fail_access:
717 return -1;
718}
719
720/**
721 * find_next_reservable_window():
722 * find a reservable space within the given range.
723 * It does not allocate the reservation window for now:
724 * alloc_new_reservation() will do the work later.
725 *
726 * @search_head: the head of the searching list;
727 * This is not necessarily the list head of the whole filesystem
728 *
729 * We have both head and start_block to assist the search
730 * for the reservable space. The list starts from head,
731 * but we will shift to the place where start_block is,
732 * then start from there, when looking for a reservable space.
733 *
734 * @size: the target new reservation window size
735 *
736 * @group_first_block: the first block we consider to start
737 * the real search from
738 *
739 * @last_block:
740 * the maximum block number that our goal reservable space
741 * could start from. This is normally the last block in this
742 * group. The search will end when we found the start of next
743 * possible reservable space is out of this boundary.
744 * This could handle the cross boundary reservation window
745 * request.
746 *
747 * basically we search from the given range, rather than the whole
748 * reservation double linked list, (start_block, last_block)
749 * to find a free region that is of my size and has not
750 * been reserved.
751 *
752 * on succeed, it returns the reservation window to be appended to.
753 * failed, return NULL.
754 */
755static struct ext3_reserve_window_node *find_next_reservable_window(
756 struct ext3_reserve_window_node *search_head,
757 unsigned long size, int *start_block,
758 int last_block)
759{
760 struct rb_node *next;
761 struct ext3_reserve_window_node *rsv, *prev;
762 int cur;
763
764 /* TODO: make the start of the reservation window byte-aligned */
765 /* cur = *start_block & ~7;*/
766 cur = *start_block;
767 rsv = search_head;
768 if (!rsv)
769 return NULL;
770
771 while (1) {
772 if (cur <= rsv->rsv_end)
773 cur = rsv->rsv_end + 1;
774
775 /* TODO?
776 * in the case we could not find a reservable space
777 * that is what is expected, during the re-search, we could
778 * remember what's the largest reservable space we could have
779 * and return that one.
780 *
781 * For now it will fail if we could not find the reservable
782 * space with expected-size (or more)...
783 */
784 if (cur > last_block)
785 return NULL; /* fail */
786
787 prev = rsv;
788 next = rb_next(&rsv->rsv_node);
789 rsv = list_entry(next, struct ext3_reserve_window_node, rsv_node);
790
791 /*
792 * Reached the last reservation, we can just append to the
793 * previous one.
794 */
795 if (!next)
796 break;
797
798 if (cur + size <= rsv->rsv_start) {
799 /*
800 * Found a reserveable space big enough. We could
801 * have a reservation across the group boundary here
802 */
803 break;
804 }
805 }
806 /*
807 * we come here either :
808 * when we reach the end of the whole list,
809 * and there is empty reservable space after last entry in the list.
810 * append it to the end of the list.
811 *
812 * or we found one reservable space in the middle of the list,
813 * return the reservation window that we could append to.
814 * succeed.
815 */
816 *start_block = cur;
817 return prev;
818}
819
820/**
821 * alloc_new_reservation()--allocate a new reservation window
822 *
823 * To make a new reservation, we search part of the filesystem
824 * reservation list (the list that inside the group). We try to
825 * allocate a new reservation window near the allocation goal,
826 * or the beginning of the group, if there is no goal.
827 *
828 * We first find a reservable space after the goal, then from
829 * there, we check the bitmap for the first free block after
830 * it. If there is no free block until the end of group, then the
831 * whole group is full, we failed. Otherwise, check if the free
832 * block is inside the expected reservable space, if so, we
833 * succeed.
834 * If the first free block is outside the reservable space, then
835 * start from the first free block, we search for next available
836 * space, and go on.
837 *
838 * on succeed, a new reservation will be found and inserted into the list
839 * It contains at least one free block, and it does not overlap with other
840 * reservation windows.
841 *
842 * failed: we failed to find a reservation window in this group
843 *
844 * @rsv: the reservation
845 *
846 * @goal: The goal (group-relative). It is where the search for a
847 * free reservable space should start from.
848 * if we have a goal(goal >0 ), then start from there,
849 * no goal(goal = -1), we start from the first block
850 * of the group.
851 *
852 * @sb: the super block
853 * @group: the group we are trying to allocate in
854 * @bitmap_bh: the block group block bitmap
855 */
856static int alloc_new_reservation(struct ext3_reserve_window_node *my_rsv,
857 int goal, struct super_block *sb,
858 unsigned int group, struct buffer_head *bitmap_bh)
859{
860 struct ext3_reserve_window_node *search_head;
861 int group_first_block, group_end_block, start_block;
862 int first_free_block;
863 int reservable_space_start;
864 struct ext3_reserve_window_node *prev_rsv;
865 struct rb_root *fs_rsv_root = &EXT3_SB(sb)->s_rsv_window_root;
866 unsigned long size;
867
868 group_first_block = le32_to_cpu(EXT3_SB(sb)->s_es->s_first_data_block) +
869 group * EXT3_BLOCKS_PER_GROUP(sb);
870 group_end_block = group_first_block + EXT3_BLOCKS_PER_GROUP(sb) - 1;
871
872 if (goal < 0)
873 start_block = group_first_block;
874 else
875 start_block = goal + group_first_block;
876
877 size = my_rsv->rsv_goal_size;
878 if (!rsv_is_empty(&my_rsv->rsv_window)) {
879 /*
880 * if the old reservation is cross group boundary
881 * and if the goal is inside the old reservation window,
882 * we will come here when we just failed to allocate from
883 * the first part of the window. We still have another part
884 * that belongs to the next group. In this case, there is no
885 * point to discard our window and try to allocate a new one
886 * in this group(which will fail). we should
887 * keep the reservation window, just simply move on.
888 *
889 * Maybe we could shift the start block of the reservation
890 * window to the first block of next group.
891 */
892
893 if ((my_rsv->rsv_start <= group_end_block) &&
894 (my_rsv->rsv_end > group_end_block) &&
895 (start_block >= my_rsv->rsv_start))
896 return -1;
897
898 if ((my_rsv->rsv_alloc_hit >
899 (my_rsv->rsv_end - my_rsv->rsv_start + 1) / 2)) {
900 /*
901 * if we previously allocation hit ration is greater than half
902 * we double the size of reservation window next time
903 * otherwise keep the same
904 */
905 size = size * 2;
906 if (size > EXT3_MAX_RESERVE_BLOCKS)
907 size = EXT3_MAX_RESERVE_BLOCKS;
908 my_rsv->rsv_goal_size= size;
909 }
910 }
911 /*
912 * shift the search start to the window near the goal block
913 */
914 search_head = search_reserve_window(fs_rsv_root, start_block);
915
916 /*
917 * find_next_reservable_window() simply finds a reservable window
918 * inside the given range(start_block, group_end_block).
919 *
920 * To make sure the reservation window has a free bit inside it, we
921 * need to check the bitmap after we found a reservable window.
922 */
923retry:
924 prev_rsv = find_next_reservable_window(search_head, size,
925 &start_block, group_end_block);
926 if (prev_rsv == NULL)
927 goto failed;
928 reservable_space_start = start_block;
929 /*
930 * On success, find_next_reservable_window() returns the
931 * reservation window where there is a reservable space after it.
932 * Before we reserve this reservable space, we need
933 * to make sure there is at least a free block inside this region.
934 *
935 * searching the first free bit on the block bitmap and copy of
936 * last committed bitmap alternatively, until we found a allocatable
937 * block. Search start from the start block of the reservable space
938 * we just found.
939 */
940 first_free_block = bitmap_search_next_usable_block(
941 reservable_space_start - group_first_block,
942 bitmap_bh, group_end_block - group_first_block + 1);
943
944 if (first_free_block < 0) {
945 /*
946 * no free block left on the bitmap, no point
947 * to reserve the space. return failed.
948 */
949 goto failed;
950 }
951 start_block = first_free_block + group_first_block;
952 /*
953 * check if the first free block is within the
954 * free space we just found
955 */
956 if ((start_block >= reservable_space_start) &&
957 (start_block < reservable_space_start + size))
958 goto found_rsv_window;
959 /*
960 * if the first free bit we found is out of the reservable space
961 * this means there is no free block on the reservable space
962 * we should continue search for next reservable space,
963 * start from where the free block is,
964 * we also shift the list head to where we stopped last time
965 */
966 search_head = prev_rsv;
967 goto retry;
968
969found_rsv_window:
970 /*
971 * great! the reservable space contains some free blocks.
972 * if the search returns that we should add the new
973 * window just next to where the old window, we don't
974 * need to remove the old window first then add it to the
975 * same place, just update the new start and new end.
976 */
977 if (my_rsv != prev_rsv) {
978 if (!rsv_is_empty(&my_rsv->rsv_window))
979 rsv_window_remove(sb, my_rsv);
980 }
981 my_rsv->rsv_start = reservable_space_start;
982 my_rsv->rsv_end = my_rsv->rsv_start + size - 1;
983 my_rsv->rsv_alloc_hit = 0;
984 if (my_rsv != prev_rsv) {
985 ext3_rsv_window_add(sb, my_rsv);
986 }
987 return 0; /* succeed */
988failed:
989 /*
990 * failed to find a new reservation window in the current
991 * group, remove the current(stale) reservation window
992 * if there is any
993 */
994 if (!rsv_is_empty(&my_rsv->rsv_window))
995 rsv_window_remove(sb, my_rsv);
996 return -1; /* failed */
997}
998
999/*
1000 * This is the main function used to allocate a new block and its reservation
1001 * window.
1002 *
1003 * Each time when a new block allocation is need, first try to allocate from
1004 * its own reservation. If it does not have a reservation window, instead of
1005 * looking for a free bit on bitmap first, then look up the reservation list to
1006 * see if it is inside somebody else's reservation window, we try to allocate a
1007 * reservation window for it starting from the goal first. Then do the block
1008 * allocation within the reservation window.
1009 *
1010 * This will avoid keeping on searching the reservation list again and
1011 * again when someboday is looking for a free block (without
1012 * reservation), and there are lots of free blocks, but they are all
1013 * being reserved.
1014 *
1015 * We use a sorted double linked list for the per-filesystem reservation list.
1016 * The insert, remove and find a free space(non-reserved) operations for the
1017 * sorted double linked list should be fast.
1018 *
1019 */
1020static int
1021ext3_try_to_allocate_with_rsv(struct super_block *sb, handle_t *handle,
1022 unsigned int group, struct buffer_head *bitmap_bh,
1023 int goal, struct ext3_reserve_window_node * my_rsv,
1024 int *errp)
1025{
1026 spinlock_t *rsv_lock;
1027 unsigned long group_first_block;
1028 int ret = 0;
1029 int fatal;
1030
1031 *errp = 0;
1032
1033 /*
1034 * Make sure we use undo access for the bitmap, because it is critical
1035 * that we do the frozen_data COW on bitmap buffers in all cases even
1036 * if the buffer is in BJ_Forget state in the committing transaction.
1037 */
1038 BUFFER_TRACE(bitmap_bh, "get undo access for new block");
1039 fatal = ext3_journal_get_undo_access(handle, bitmap_bh);
1040 if (fatal) {
1041 *errp = fatal;
1042 return -1;
1043 }
1044
1045 /*
1046 * we don't deal with reservation when
1047 * filesystem is mounted without reservation
1048 * or the file is not a regular file
1049 * or last attempt to allocate a block with reservation turned on failed
1050 */
1051 if (my_rsv == NULL ) {
1052 ret = ext3_try_to_allocate(sb, handle, group, bitmap_bh, goal, NULL);
1053 goto out;
1054 }
1055 rsv_lock = &EXT3_SB(sb)->s_rsv_window_lock;
1056 /*
1057 * goal is a group relative block number (if there is a goal)
1058 * 0 < goal < EXT3_BLOCKS_PER_GROUP(sb)
1059 * first block is a filesystem wide block number
1060 * first block is the block number of the first block in this group
1061 */
1062 group_first_block = le32_to_cpu(EXT3_SB(sb)->s_es->s_first_data_block) +
1063 group * EXT3_BLOCKS_PER_GROUP(sb);
1064
1065 /*
1066 * Basically we will allocate a new block from inode's reservation
1067 * window.
1068 *
1069 * We need to allocate a new reservation window, if:
1070 * a) inode does not have a reservation window; or
1071 * b) last attempt to allocate a block from existing reservation
1072 * failed; or
1073 * c) we come here with a goal and with a reservation window
1074 *
1075 * We do not need to allocate a new reservation window if we come here
1076 * at the beginning with a goal and the goal is inside the window, or
1077 * we don't have a goal but already have a reservation window.
1078 * then we could go to allocate from the reservation window directly.
1079 */
1080 while (1) {
1081 struct ext3_reserve_window rsv_copy;
1082
1083 rsv_copy._rsv_start = my_rsv->rsv_start;
1084 rsv_copy._rsv_end = my_rsv->rsv_end;
1085
1086 if (rsv_is_empty(&rsv_copy) || (ret < 0) ||
1087 !goal_in_my_reservation(&rsv_copy, goal, group, sb)) {
1088 spin_lock(rsv_lock);
1089 ret = alloc_new_reservation(my_rsv, goal, sb,
1090 group, bitmap_bh);
1091 rsv_copy._rsv_start = my_rsv->rsv_start;
1092 rsv_copy._rsv_end = my_rsv->rsv_end;
1093 spin_unlock(rsv_lock);
1094 if (ret < 0)
1095 break; /* failed */
1096
1097 if (!goal_in_my_reservation(&rsv_copy, goal, group, sb))
1098 goal = -1;
1099 }
1100 if ((rsv_copy._rsv_start >= group_first_block + EXT3_BLOCKS_PER_GROUP(sb))
1101 || (rsv_copy._rsv_end < group_first_block))
1102 BUG();
1103 ret = ext3_try_to_allocate(sb, handle, group, bitmap_bh, goal,
1104 &rsv_copy);
1105 if (ret >= 0) {
1106 my_rsv->rsv_alloc_hit++;
1107 break; /* succeed */
1108 }
1109 }
1110out:
1111 if (ret >= 0) {
1112 BUFFER_TRACE(bitmap_bh, "journal_dirty_metadata for "
1113 "bitmap block");
1114 fatal = ext3_journal_dirty_metadata(handle, bitmap_bh);
1115 if (fatal) {
1116 *errp = fatal;
1117 return -1;
1118 }
1119 return ret;
1120 }
1121
1122 BUFFER_TRACE(bitmap_bh, "journal_release_buffer");
1123 ext3_journal_release_buffer(handle, bitmap_bh);
1124 return ret;
1125}
1126
1127static int ext3_has_free_blocks(struct ext3_sb_info *sbi)
1128{
1129 int free_blocks, root_blocks;
1130
1131 free_blocks = percpu_counter_read_positive(&sbi->s_freeblocks_counter);
1132 root_blocks = le32_to_cpu(sbi->s_es->s_r_blocks_count);
1133 if (free_blocks < root_blocks + 1 && !capable(CAP_SYS_RESOURCE) &&
1134 sbi->s_resuid != current->fsuid &&
1135 (sbi->s_resgid == 0 || !in_group_p (sbi->s_resgid))) {
1136 return 0;
1137 }
1138 return 1;
1139}
1140
1141/*
1142 * ext3_should_retry_alloc() is called when ENOSPC is returned, and if
1143 * it is profitable to retry the operation, this function will wait
1144 * for the current or commiting transaction to complete, and then
1145 * return TRUE.
1146 */
1147int ext3_should_retry_alloc(struct super_block *sb, int *retries)
1148{
1149 if (!ext3_has_free_blocks(EXT3_SB(sb)) || (*retries)++ > 3)
1150 return 0;
1151
1152 jbd_debug(1, "%s: retrying operation after ENOSPC\n", sb->s_id);
1153
1154 return journal_force_commit_nested(EXT3_SB(sb)->s_journal);
1155}
1156
1157/*
1158 * ext3_new_block uses a goal block to assist allocation. If the goal is
1159 * free, or there is a free block within 32 blocks of the goal, that block
1160 * is allocated. Otherwise a forward search is made for a free block; within
1161 * each block group the search first looks for an entire free byte in the block
1162 * bitmap, and then for any free bit if that fails.
1163 * This function also updates quota and i_blocks field.
1164 */
1165int ext3_new_block(handle_t *handle, struct inode *inode,
1166 unsigned long goal, int *errp)
1167{
1168 struct buffer_head *bitmap_bh = NULL;
1169 struct buffer_head *gdp_bh;
1170 int group_no;
1171 int goal_group;
1172 int ret_block;
1173 int bgi; /* blockgroup iteration index */
1174 int target_block;
1175 int fatal = 0, err;
1176 int performed_allocation = 0;
1177 int free_blocks;
1178 struct super_block *sb;
1179 struct ext3_group_desc *gdp;
1180 struct ext3_super_block *es;
1181 struct ext3_sb_info *sbi;
1182 struct ext3_reserve_window_node *my_rsv = NULL;
1183 struct ext3_block_alloc_info *block_i;
1184 unsigned short windowsz = 0;
1185#ifdef EXT3FS_DEBUG
1186 static int goal_hits, goal_attempts;
1187#endif
1188 unsigned long ngroups;
1189
1190 *errp = -ENOSPC;
1191 sb = inode->i_sb;
1192 if (!sb) {
1193 printk("ext3_new_block: nonexistent device");
1194 return 0;
1195 }
1196
1197 /*
1198 * Check quota for allocation of this block.
1199 */
1200 if (DQUOT_ALLOC_BLOCK(inode, 1)) {
1201 *errp = -EDQUOT;
1202 return 0;
1203 }
1204
1205 sbi = EXT3_SB(sb);
1206 es = EXT3_SB(sb)->s_es;
1207 ext3_debug("goal=%lu.\n", goal);
1208 /*
1209 * Allocate a block from reservation only when
1210 * filesystem is mounted with reservation(default,-o reservation), and
1211 * it's a regular file, and
1212 * the desired window size is greater than 0 (One could use ioctl
1213 * command EXT3_IOC_SETRSVSZ to set the window size to 0 to turn off
1214 * reservation on that particular file)
1215 */
1216 block_i = EXT3_I(inode)->i_block_alloc_info;
1217 if (block_i && ((windowsz = block_i->rsv_window_node.rsv_goal_size) > 0))
1218 my_rsv = &block_i->rsv_window_node;
1219
1220 if (!ext3_has_free_blocks(sbi)) {
1221 *errp = -ENOSPC;
1222 goto out;
1223 }
1224
1225 /*
1226 * First, test whether the goal block is free.
1227 */
1228 if (goal < le32_to_cpu(es->s_first_data_block) ||
1229 goal >= le32_to_cpu(es->s_blocks_count))
1230 goal = le32_to_cpu(es->s_first_data_block);
1231 group_no = (goal - le32_to_cpu(es->s_first_data_block)) /
1232 EXT3_BLOCKS_PER_GROUP(sb);
1233 gdp = ext3_get_group_desc(sb, group_no, &gdp_bh);
1234 if (!gdp)
1235 goto io_error;
1236
1237 goal_group = group_no;
1238retry:
1239 free_blocks = le16_to_cpu(gdp->bg_free_blocks_count);
1240 /*
1241 * if there is not enough free blocks to make a new resevation
1242 * turn off reservation for this allocation
1243 */
1244 if (my_rsv && (free_blocks < windowsz)
1245 && (rsv_is_empty(&my_rsv->rsv_window)))
1246 my_rsv = NULL;
1247
1248 if (free_blocks > 0) {
1249 ret_block = ((goal - le32_to_cpu(es->s_first_data_block)) %
1250 EXT3_BLOCKS_PER_GROUP(sb));
1251 bitmap_bh = read_block_bitmap(sb, group_no);
1252 if (!bitmap_bh)
1253 goto io_error;
1254 ret_block = ext3_try_to_allocate_with_rsv(sb, handle, group_no,
1255 bitmap_bh, ret_block, my_rsv, &fatal);
1256 if (fatal)
1257 goto out;
1258 if (ret_block >= 0)
1259 goto allocated;
1260 }
1261
1262 ngroups = EXT3_SB(sb)->s_groups_count;
1263 smp_rmb();
1264
1265 /*
1266 * Now search the rest of the groups. We assume that
1267 * i and gdp correctly point to the last group visited.
1268 */
1269 for (bgi = 0; bgi < ngroups; bgi++) {
1270 group_no++;
1271 if (group_no >= ngroups)
1272 group_no = 0;
1273 gdp = ext3_get_group_desc(sb, group_no, &gdp_bh);
1274 if (!gdp) {
1275 *errp = -EIO;
1276 goto out;
1277 }
1278 free_blocks = le16_to_cpu(gdp->bg_free_blocks_count);
1279 /*
1280 * skip this group if the number of
1281 * free blocks is less than half of the reservation
1282 * window size.
1283 */
1284 if (free_blocks <= (windowsz/2))
1285 continue;
1286
1287 brelse(bitmap_bh);
1288 bitmap_bh = read_block_bitmap(sb, group_no);
1289 if (!bitmap_bh)
1290 goto io_error;
1291 ret_block = ext3_try_to_allocate_with_rsv(sb, handle, group_no,
1292 bitmap_bh, -1, my_rsv, &fatal);
1293 if (fatal)
1294 goto out;
1295 if (ret_block >= 0)
1296 goto allocated;
1297 }
1298 /*
1299 * We may end up a bogus ealier ENOSPC error due to
1300 * filesystem is "full" of reservations, but
1301 * there maybe indeed free blocks avaliable on disk
1302 * In this case, we just forget about the reservations
1303 * just do block allocation as without reservations.
1304 */
1305 if (my_rsv) {
1306 my_rsv = NULL;
1307 group_no = goal_group;
1308 goto retry;
1309 }
1310 /* No space left on the device */
1311 *errp = -ENOSPC;
1312 goto out;
1313
1314allocated:
1315
1316 ext3_debug("using block group %d(%d)\n",
1317 group_no, gdp->bg_free_blocks_count);
1318
1319 BUFFER_TRACE(gdp_bh, "get_write_access");
1320 fatal = ext3_journal_get_write_access(handle, gdp_bh);
1321 if (fatal)
1322 goto out;
1323
1324 target_block = ret_block + group_no * EXT3_BLOCKS_PER_GROUP(sb)
1325 + le32_to_cpu(es->s_first_data_block);
1326
1327 if (target_block == le32_to_cpu(gdp->bg_block_bitmap) ||
1328 target_block == le32_to_cpu(gdp->bg_inode_bitmap) ||
1329 in_range(target_block, le32_to_cpu(gdp->bg_inode_table),
1330 EXT3_SB(sb)->s_itb_per_group))
1331 ext3_error(sb, "ext3_new_block",
1332 "Allocating block in system zone - "
1333 "block = %u", target_block);
1334
1335 performed_allocation = 1;
1336
1337#ifdef CONFIG_JBD_DEBUG
1338 {
1339 struct buffer_head *debug_bh;
1340
1341 /* Record bitmap buffer state in the newly allocated block */
1342 debug_bh = sb_find_get_block(sb, target_block);
1343 if (debug_bh) {
1344 BUFFER_TRACE(debug_bh, "state when allocated");
1345 BUFFER_TRACE2(debug_bh, bitmap_bh, "bitmap state");
1346 brelse(debug_bh);
1347 }
1348 }
1349 jbd_lock_bh_state(bitmap_bh);
1350 spin_lock(sb_bgl_lock(sbi, group_no));
1351 if (buffer_jbd(bitmap_bh) && bh2jh(bitmap_bh)->b_committed_data) {
1352 if (ext3_test_bit(ret_block,
1353 bh2jh(bitmap_bh)->b_committed_data)) {
1354 printk("%s: block was unexpectedly set in "
1355 "b_committed_data\n", __FUNCTION__);
1356 }
1357 }
1358 ext3_debug("found bit %d\n", ret_block);
1359 spin_unlock(sb_bgl_lock(sbi, group_no));
1360 jbd_unlock_bh_state(bitmap_bh);
1361#endif
1362
1363 /* ret_block was blockgroup-relative. Now it becomes fs-relative */
1364 ret_block = target_block;
1365
1366 if (ret_block >= le32_to_cpu(es->s_blocks_count)) {
1367 ext3_error(sb, "ext3_new_block",
1368 "block(%d) >= blocks count(%d) - "
1369 "block_group = %d, es == %p ", ret_block,
1370 le32_to_cpu(es->s_blocks_count), group_no, es);
1371 goto out;
1372 }
1373
1374 /*
1375 * It is up to the caller to add the new buffer to a journal
1376 * list of some description. We don't know in advance whether
1377 * the caller wants to use it as metadata or data.
1378 */
1379 ext3_debug("allocating block %d. Goal hits %d of %d.\n",
1380 ret_block, goal_hits, goal_attempts);
1381
1382 spin_lock(sb_bgl_lock(sbi, group_no));
1383 gdp->bg_free_blocks_count =
1384 cpu_to_le16(le16_to_cpu(gdp->bg_free_blocks_count) - 1);
1385 spin_unlock(sb_bgl_lock(sbi, group_no));
1386 percpu_counter_mod(&sbi->s_freeblocks_counter, -1);
1387
1388 BUFFER_TRACE(gdp_bh, "journal_dirty_metadata for group descriptor");
1389 err = ext3_journal_dirty_metadata(handle, gdp_bh);
1390 if (!fatal)
1391 fatal = err;
1392
1393 sb->s_dirt = 1;
1394 if (fatal)
1395 goto out;
1396
1397 *errp = 0;
1398 brelse(bitmap_bh);
1399 return ret_block;
1400
1401io_error:
1402 *errp = -EIO;
1403out:
1404 if (fatal) {
1405 *errp = fatal;
1406 ext3_std_error(sb, fatal);
1407 }
1408 /*
1409 * Undo the block allocation
1410 */
1411 if (!performed_allocation)
1412 DQUOT_FREE_BLOCK(inode, 1);
1413 brelse(bitmap_bh);
1414 return 0;
1415}
1416
1417unsigned long ext3_count_free_blocks(struct super_block *sb)
1418{
1419 unsigned long desc_count;
1420 struct ext3_group_desc *gdp;
1421 int i;
1422 unsigned long ngroups;
1423#ifdef EXT3FS_DEBUG
1424 struct ext3_super_block *es;
1425 unsigned long bitmap_count, x;
1426 struct buffer_head *bitmap_bh = NULL;
1427
1428 lock_super(sb);
1429 es = EXT3_SB(sb)->s_es;
1430 desc_count = 0;
1431 bitmap_count = 0;
1432 gdp = NULL;
1433 for (i = 0; i < EXT3_SB(sb)->s_groups_count; i++) {
1434 gdp = ext3_get_group_desc(sb, i, NULL);
1435 if (!gdp)
1436 continue;
1437 desc_count += le16_to_cpu(gdp->bg_free_blocks_count);
1438 brelse(bitmap_bh);
1439 bitmap_bh = read_block_bitmap(sb, i);
1440 if (bitmap_bh == NULL)
1441 continue;
1442
1443 x = ext3_count_free(bitmap_bh, sb->s_blocksize);
1444 printk("group %d: stored = %d, counted = %lu\n",
1445 i, le16_to_cpu(gdp->bg_free_blocks_count), x);
1446 bitmap_count += x;
1447 }
1448 brelse(bitmap_bh);
1449 printk("ext3_count_free_blocks: stored = %u, computed = %lu, %lu\n",
1450 le32_to_cpu(es->s_free_blocks_count), desc_count, bitmap_count);
1451 unlock_super(sb);
1452 return bitmap_count;
1453#else
1454 desc_count = 0;
1455 ngroups = EXT3_SB(sb)->s_groups_count;
1456 smp_rmb();
1457 for (i = 0; i < ngroups; i++) {
1458 gdp = ext3_get_group_desc(sb, i, NULL);
1459 if (!gdp)
1460 continue;
1461 desc_count += le16_to_cpu(gdp->bg_free_blocks_count);
1462 }
1463
1464 return desc_count;
1465#endif
1466}
1467
1468static inline int
1469block_in_use(unsigned long block, struct super_block *sb, unsigned char *map)
1470{
1471 return ext3_test_bit ((block -
1472 le32_to_cpu(EXT3_SB(sb)->s_es->s_first_data_block)) %
1473 EXT3_BLOCKS_PER_GROUP(sb), map);
1474}
1475
1476static inline int test_root(int a, int b)
1477{
1478 int num = b;
1479
1480 while (a > num)
1481 num *= b;
1482 return num == a;
1483}
1484
1485static int ext3_group_sparse(int group)
1486{
1487 if (group <= 1)
1488 return 1;
1489 if (!(group & 1))
1490 return 0;
1491 return (test_root(group, 7) || test_root(group, 5) ||
1492 test_root(group, 3));
1493}
1494
1495/**
1496 * ext3_bg_has_super - number of blocks used by the superblock in group
1497 * @sb: superblock for filesystem
1498 * @group: group number to check
1499 *
1500 * Return the number of blocks used by the superblock (primary or backup)
1501 * in this group. Currently this will be only 0 or 1.
1502 */
1503int ext3_bg_has_super(struct super_block *sb, int group)
1504{
1505 if (EXT3_HAS_RO_COMPAT_FEATURE(sb,EXT3_FEATURE_RO_COMPAT_SPARSE_SUPER)&&
1506 !ext3_group_sparse(group))
1507 return 0;
1508 return 1;
1509}
1510
1511/**
1512 * ext3_bg_num_gdb - number of blocks used by the group table in group
1513 * @sb: superblock for filesystem
1514 * @group: group number to check
1515 *
1516 * Return the number of blocks used by the group descriptor table
1517 * (primary or backup) in this group. In the future there may be a
1518 * different number of descriptor blocks in each group.
1519 */
1520unsigned long ext3_bg_num_gdb(struct super_block *sb, int group)
1521{
1522 if (EXT3_HAS_RO_COMPAT_FEATURE(sb,EXT3_FEATURE_RO_COMPAT_SPARSE_SUPER)&&
1523 !ext3_group_sparse(group))
1524 return 0;
1525 return EXT3_SB(sb)->s_gdb_count;
1526}
1527
1528#ifdef CONFIG_EXT3_CHECK
1529/* Called at mount-time, super-block is locked */
1530void ext3_check_blocks_bitmap (struct super_block * sb)
1531{
1532 struct ext3_super_block *es;
1533 unsigned long desc_count, bitmap_count, x, j;
1534 unsigned long desc_blocks;
1535 struct buffer_head *bitmap_bh = NULL;
1536 struct ext3_group_desc *gdp;
1537 int i;
1538
1539 es = EXT3_SB(sb)->s_es;
1540 desc_count = 0;
1541 bitmap_count = 0;
1542 gdp = NULL;
1543 for (i = 0; i < EXT3_SB(sb)->s_groups_count; i++) {
1544 gdp = ext3_get_group_desc (sb, i, NULL);
1545 if (!gdp)
1546 continue;
1547 desc_count += le16_to_cpu(gdp->bg_free_blocks_count);
1548 brelse(bitmap_bh);
1549 bitmap_bh = read_block_bitmap(sb, i);
1550 if (bitmap_bh == NULL)
1551 continue;
1552
1553 if (ext3_bg_has_super(sb, i) &&
1554 !ext3_test_bit(0, bitmap_bh->b_data))
1555 ext3_error(sb, __FUNCTION__,
1556 "Superblock in group %d is marked free", i);
1557
1558 desc_blocks = ext3_bg_num_gdb(sb, i);
1559 for (j = 0; j < desc_blocks; j++)
1560 if (!ext3_test_bit(j + 1, bitmap_bh->b_data))
1561 ext3_error(sb, __FUNCTION__,
1562 "Descriptor block #%ld in group "
1563 "%d is marked free", j, i);
1564
1565 if (!block_in_use (le32_to_cpu(gdp->bg_block_bitmap),
1566 sb, bitmap_bh->b_data))
1567 ext3_error (sb, "ext3_check_blocks_bitmap",
1568 "Block bitmap for group %d is marked free",
1569 i);
1570
1571 if (!block_in_use (le32_to_cpu(gdp->bg_inode_bitmap),
1572 sb, bitmap_bh->b_data))
1573 ext3_error (sb, "ext3_check_blocks_bitmap",
1574 "Inode bitmap for group %d is marked free",
1575 i);
1576
1577 for (j = 0; j < EXT3_SB(sb)->s_itb_per_group; j++)
1578 if (!block_in_use (le32_to_cpu(gdp->bg_inode_table) + j,
1579 sb, bitmap_bh->b_data))
1580 ext3_error (sb, "ext3_check_blocks_bitmap",
1581 "Block #%d of the inode table in "
1582 "group %d is marked free", j, i);
1583
1584 x = ext3_count_free(bitmap_bh, sb->s_blocksize);
1585 if (le16_to_cpu(gdp->bg_free_blocks_count) != x)
1586 ext3_error (sb, "ext3_check_blocks_bitmap",
1587 "Wrong free blocks count for group %d, "
1588 "stored = %d, counted = %lu", i,
1589 le16_to_cpu(gdp->bg_free_blocks_count), x);
1590 bitmap_count += x;
1591 }
1592 brelse(bitmap_bh);
1593 if (le32_to_cpu(es->s_free_blocks_count) != bitmap_count)
1594 ext3_error (sb, "ext3_check_blocks_bitmap",
1595 "Wrong free blocks count in super block, "
1596 "stored = %lu, counted = %lu",
1597 (unsigned long)le32_to_cpu(es->s_free_blocks_count),
1598 bitmap_count);
1599}
1600#endif
generated by cgit v1.2.2 (git 2.25.0) at 2024-12-16 05:40:47 -0500