blob: 77927d6938f61d369e0f64f4bfec1637d2ebd203 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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>
Randy Dunlap16f7e0f2006-01-11 12:17:46 -080016#include <linux/capability.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070017#include <linux/fs.h>
18#include <linux/jbd.h>
19#include <linux/ext3_fs.h>
20#include <linux/ext3_jbd.h>
21#include <linux/quotaops.h>
22#include <linux/buffer_head.h>
23
24/*
25 * balloc.c contains the blocks allocation and deallocation routines
26 */
27
28/*
29 * The free blocks are managed by bitmaps. A file system contains several
30 * blocks groups. Each group contains 1 bitmap block for blocks, 1 bitmap
31 * block for inodes, N blocks for the inode table and data blocks.
32 *
33 * The file system contains group descriptors which are located after the
34 * super block. Each descriptor contains the number of the bitmap block and
35 * the free blocks count in the block. The descriptors are loaded in memory
36 * when a file system is mounted (see ext3_read_super).
37 */
38
39
40#define in_range(b, first, len) ((b) >= (first) && (b) <= (first) + (len) - 1)
41
42struct ext3_group_desc * ext3_get_group_desc(struct super_block * sb,
43 unsigned int block_group,
44 struct buffer_head ** bh)
45{
46 unsigned long group_desc;
47 unsigned long offset;
48 struct ext3_group_desc * desc;
49 struct ext3_sb_info *sbi = EXT3_SB(sb);
50
51 if (block_group >= sbi->s_groups_count) {
52 ext3_error (sb, "ext3_get_group_desc",
53 "block_group >= groups_count - "
54 "block_group = %d, groups_count = %lu",
55 block_group, sbi->s_groups_count);
56
57 return NULL;
58 }
59 smp_rmb();
60
61 group_desc = block_group >> EXT3_DESC_PER_BLOCK_BITS(sb);
62 offset = block_group & (EXT3_DESC_PER_BLOCK(sb) - 1);
63 if (!sbi->s_group_desc[group_desc]) {
64 ext3_error (sb, "ext3_get_group_desc",
65 "Group descriptor not loaded - "
66 "block_group = %d, group_desc = %lu, desc = %lu",
67 block_group, group_desc, offset);
68 return NULL;
69 }
70
71 desc = (struct ext3_group_desc *) sbi->s_group_desc[group_desc]->b_data;
72 if (bh)
73 *bh = sbi->s_group_desc[group_desc];
74 return desc + offset;
75}
76
77/*
78 * Read the bitmap for a given block_group, reading into the specified
79 * slot in the superblock's bitmap cache.
80 *
81 * Return buffer_head on success or NULL in case of failure.
82 */
83static struct buffer_head *
84read_block_bitmap(struct super_block *sb, unsigned int block_group)
85{
86 struct ext3_group_desc * desc;
87 struct buffer_head * bh = NULL;
88
89 desc = ext3_get_group_desc (sb, block_group, NULL);
90 if (!desc)
91 goto error_out;
92 bh = sb_bread(sb, le32_to_cpu(desc->bg_block_bitmap));
93 if (!bh)
94 ext3_error (sb, "read_block_bitmap",
95 "Cannot read block bitmap - "
96 "block_group = %d, block_bitmap = %u",
97 block_group, le32_to_cpu(desc->bg_block_bitmap));
98error_out:
99 return bh;
100}
101/*
102 * The reservation window structure operations
103 * --------------------------------------------
104 * Operations include:
105 * dump, find, add, remove, is_empty, find_next_reservable_window, etc.
106 *
107 * We use sorted double linked list for the per-filesystem reservation
108 * window list. (like in vm_region).
109 *
110 * Initially, we keep those small operations in the abstract functions,
111 * so later if we need a better searching tree than double linked-list,
112 * we could easily switch to that without changing too much
113 * code.
114 */
115#if 0
116static void __rsv_window_dump(struct rb_root *root, int verbose,
117 const char *fn)
118{
119 struct rb_node *n;
120 struct ext3_reserve_window_node *rsv, *prev;
121 int bad;
122
123restart:
124 n = rb_first(root);
125 bad = 0;
126 prev = NULL;
127
128 printk("Block Allocation Reservation Windows Map (%s):\n", fn);
129 while (n) {
130 rsv = list_entry(n, struct ext3_reserve_window_node, rsv_node);
131 if (verbose)
132 printk("reservation window 0x%p "
133 "start: %d, end: %d\n",
134 rsv, rsv->rsv_start, rsv->rsv_end);
135 if (rsv->rsv_start && rsv->rsv_start >= rsv->rsv_end) {
136 printk("Bad reservation %p (start >= end)\n",
137 rsv);
138 bad = 1;
139 }
140 if (prev && prev->rsv_end >= rsv->rsv_start) {
141 printk("Bad reservation %p (prev->end >= start)\n",
142 rsv);
143 bad = 1;
144 }
145 if (bad) {
146 if (!verbose) {
147 printk("Restarting reservation walk in verbose mode\n");
148 verbose = 1;
149 goto restart;
150 }
151 }
152 n = rb_next(n);
153 prev = rsv;
154 }
155 printk("Window map complete.\n");
156 if (bad)
157 BUG();
158}
159#define rsv_window_dump(root, verbose) \
160 __rsv_window_dump((root), (verbose), __FUNCTION__)
161#else
162#define rsv_window_dump(root, verbose) do {} while (0)
163#endif
164
165static int
166goal_in_my_reservation(struct ext3_reserve_window *rsv, int goal,
167 unsigned int group, struct super_block * sb)
168{
169 unsigned long group_first_block, group_last_block;
170
171 group_first_block = le32_to_cpu(EXT3_SB(sb)->s_es->s_first_data_block) +
172 group * EXT3_BLOCKS_PER_GROUP(sb);
173 group_last_block = group_first_block + EXT3_BLOCKS_PER_GROUP(sb) - 1;
174
175 if ((rsv->_rsv_start > group_last_block) ||
176 (rsv->_rsv_end < group_first_block))
177 return 0;
178 if ((goal >= 0) && ((goal + group_first_block < rsv->_rsv_start)
179 || (goal + group_first_block > rsv->_rsv_end)))
180 return 0;
181 return 1;
182}
183
184/*
185 * Find the reserved window which includes the goal, or the previous one
186 * if the goal is not in any window.
187 * Returns NULL if there are no windows or if all windows start after the goal.
188 */
189static struct ext3_reserve_window_node *
190search_reserve_window(struct rb_root *root, unsigned long goal)
191{
192 struct rb_node *n = root->rb_node;
193 struct ext3_reserve_window_node *rsv;
194
195 if (!n)
196 return NULL;
197
198 do {
199 rsv = rb_entry(n, struct ext3_reserve_window_node, rsv_node);
200
201 if (goal < rsv->rsv_start)
202 n = n->rb_left;
203 else if (goal > rsv->rsv_end)
204 n = n->rb_right;
205 else
206 return rsv;
207 } while (n);
208 /*
209 * We've fallen off the end of the tree: the goal wasn't inside
210 * any particular node. OK, the previous node must be to one
211 * side of the interval containing the goal. If it's the RHS,
212 * we need to back up one.
213 */
214 if (rsv->rsv_start > goal) {
215 n = rb_prev(&rsv->rsv_node);
216 rsv = rb_entry(n, struct ext3_reserve_window_node, rsv_node);
217 }
218 return rsv;
219}
220
221void ext3_rsv_window_add(struct super_block *sb,
222 struct ext3_reserve_window_node *rsv)
223{
224 struct rb_root *root = &EXT3_SB(sb)->s_rsv_window_root;
225 struct rb_node *node = &rsv->rsv_node;
226 unsigned int start = rsv->rsv_start;
227
228 struct rb_node ** p = &root->rb_node;
229 struct rb_node * parent = NULL;
230 struct ext3_reserve_window_node *this;
231
232 while (*p)
233 {
234 parent = *p;
235 this = rb_entry(parent, struct ext3_reserve_window_node, rsv_node);
236
237 if (start < this->rsv_start)
238 p = &(*p)->rb_left;
239 else if (start > this->rsv_end)
240 p = &(*p)->rb_right;
241 else
242 BUG();
243 }
244
245 rb_link_node(node, parent, p);
246 rb_insert_color(node, root);
247}
248
249static void rsv_window_remove(struct super_block *sb,
250 struct ext3_reserve_window_node *rsv)
251{
252 rsv->rsv_start = EXT3_RESERVE_WINDOW_NOT_ALLOCATED;
253 rsv->rsv_end = EXT3_RESERVE_WINDOW_NOT_ALLOCATED;
254 rsv->rsv_alloc_hit = 0;
255 rb_erase(&rsv->rsv_node, &EXT3_SB(sb)->s_rsv_window_root);
256}
257
258static inline int rsv_is_empty(struct ext3_reserve_window *rsv)
259{
260 /* a valid reservation end block could not be 0 */
261 return (rsv->_rsv_end == EXT3_RESERVE_WINDOW_NOT_ALLOCATED);
262}
263void ext3_init_block_alloc_info(struct inode *inode)
264{
265 struct ext3_inode_info *ei = EXT3_I(inode);
266 struct ext3_block_alloc_info *block_i = ei->i_block_alloc_info;
267 struct super_block *sb = inode->i_sb;
268
269 block_i = kmalloc(sizeof(*block_i), GFP_NOFS);
270 if (block_i) {
271 struct ext3_reserve_window_node *rsv = &block_i->rsv_window_node;
272
273 rsv->rsv_start = EXT3_RESERVE_WINDOW_NOT_ALLOCATED;
274 rsv->rsv_end = EXT3_RESERVE_WINDOW_NOT_ALLOCATED;
275
276 /*
277 * if filesystem is mounted with NORESERVATION, the goal
278 * reservation window size is set to zero to indicate
279 * block reservation is off
280 */
281 if (!test_opt(sb, RESERVATION))
282 rsv->rsv_goal_size = 0;
283 else
284 rsv->rsv_goal_size = EXT3_DEFAULT_RESERVE_BLOCKS;
285 rsv->rsv_alloc_hit = 0;
286 block_i->last_alloc_logical_block = 0;
287 block_i->last_alloc_physical_block = 0;
288 }
289 ei->i_block_alloc_info = block_i;
290}
291
292void ext3_discard_reservation(struct inode *inode)
293{
294 struct ext3_inode_info *ei = EXT3_I(inode);
295 struct ext3_block_alloc_info *block_i = ei->i_block_alloc_info;
296 struct ext3_reserve_window_node *rsv;
297 spinlock_t *rsv_lock = &EXT3_SB(inode->i_sb)->s_rsv_window_lock;
298
299 if (!block_i)
300 return;
301
302 rsv = &block_i->rsv_window_node;
303 if (!rsv_is_empty(&rsv->rsv_window)) {
304 spin_lock(rsv_lock);
305 if (!rsv_is_empty(&rsv->rsv_window))
306 rsv_window_remove(inode->i_sb, rsv);
307 spin_unlock(rsv_lock);
308 }
309}
310
311/* Free given blocks, update quota and i_blocks field */
312void ext3_free_blocks_sb(handle_t *handle, struct super_block *sb,
313 unsigned long block, unsigned long count,
314 int *pdquot_freed_blocks)
315{
316 struct buffer_head *bitmap_bh = NULL;
317 struct buffer_head *gd_bh;
318 unsigned long block_group;
319 unsigned long bit;
320 unsigned long i;
321 unsigned long overflow;
322 struct ext3_group_desc * desc;
323 struct ext3_super_block * es;
324 struct ext3_sb_info *sbi;
325 int err = 0, ret;
326 unsigned group_freed;
327
328 *pdquot_freed_blocks = 0;
329 sbi = EXT3_SB(sb);
330 es = sbi->s_es;
331 if (block < le32_to_cpu(es->s_first_data_block) ||
332 block + count < block ||
333 block + count > le32_to_cpu(es->s_blocks_count)) {
334 ext3_error (sb, "ext3_free_blocks",
335 "Freeing blocks not in datazone - "
336 "block = %lu, count = %lu", block, count);
337 goto error_return;
338 }
339
340 ext3_debug ("freeing block(s) %lu-%lu\n", block, block + count - 1);
341
342do_more:
343 overflow = 0;
344 block_group = (block - le32_to_cpu(es->s_first_data_block)) /
345 EXT3_BLOCKS_PER_GROUP(sb);
346 bit = (block - le32_to_cpu(es->s_first_data_block)) %
347 EXT3_BLOCKS_PER_GROUP(sb);
348 /*
349 * Check to see if we are freeing blocks across a group
350 * boundary.
351 */
352 if (bit + count > EXT3_BLOCKS_PER_GROUP(sb)) {
353 overflow = bit + count - EXT3_BLOCKS_PER_GROUP(sb);
354 count -= overflow;
355 }
356 brelse(bitmap_bh);
357 bitmap_bh = read_block_bitmap(sb, block_group);
358 if (!bitmap_bh)
359 goto error_return;
360 desc = ext3_get_group_desc (sb, block_group, &gd_bh);
361 if (!desc)
362 goto error_return;
363
364 if (in_range (le32_to_cpu(desc->bg_block_bitmap), block, count) ||
365 in_range (le32_to_cpu(desc->bg_inode_bitmap), block, count) ||
366 in_range (block, le32_to_cpu(desc->bg_inode_table),
367 sbi->s_itb_per_group) ||
368 in_range (block + count - 1, le32_to_cpu(desc->bg_inode_table),
369 sbi->s_itb_per_group))
370 ext3_error (sb, "ext3_free_blocks",
371 "Freeing blocks in system zones - "
372 "Block = %lu, count = %lu",
373 block, count);
374
375 /*
376 * We are about to start releasing blocks in the bitmap,
377 * so we need undo access.
378 */
379 /* @@@ check errors */
380 BUFFER_TRACE(bitmap_bh, "getting undo access");
381 err = ext3_journal_get_undo_access(handle, bitmap_bh);
382 if (err)
383 goto error_return;
384
385 /*
386 * We are about to modify some metadata. Call the journal APIs
387 * to unshare ->b_data if a currently-committing transaction is
388 * using it
389 */
390 BUFFER_TRACE(gd_bh, "get_write_access");
391 err = ext3_journal_get_write_access(handle, gd_bh);
392 if (err)
393 goto error_return;
394
395 jbd_lock_bh_state(bitmap_bh);
396
397 for (i = 0, group_freed = 0; i < count; i++) {
398 /*
399 * An HJ special. This is expensive...
400 */
401#ifdef CONFIG_JBD_DEBUG
402 jbd_unlock_bh_state(bitmap_bh);
403 {
404 struct buffer_head *debug_bh;
405 debug_bh = sb_find_get_block(sb, block + i);
406 if (debug_bh) {
407 BUFFER_TRACE(debug_bh, "Deleted!");
408 if (!bh2jh(bitmap_bh)->b_committed_data)
409 BUFFER_TRACE(debug_bh,
410 "No commited data in bitmap");
411 BUFFER_TRACE2(debug_bh, bitmap_bh, "bitmap");
412 __brelse(debug_bh);
413 }
414 }
415 jbd_lock_bh_state(bitmap_bh);
416#endif
417 if (need_resched()) {
418 jbd_unlock_bh_state(bitmap_bh);
419 cond_resched();
420 jbd_lock_bh_state(bitmap_bh);
421 }
422 /* @@@ This prevents newly-allocated data from being
423 * freed and then reallocated within the same
424 * transaction.
425 *
426 * Ideally we would want to allow that to happen, but to
427 * do so requires making journal_forget() capable of
428 * revoking the queued write of a data block, which
429 * implies blocking on the journal lock. *forget()
430 * cannot block due to truncate races.
431 *
432 * Eventually we can fix this by making journal_forget()
433 * return a status indicating whether or not it was able
434 * to revoke the buffer. On successful revoke, it is
435 * safe not to set the allocation bit in the committed
436 * bitmap, because we know that there is no outstanding
437 * activity on the buffer any more and so it is safe to
438 * reallocate it.
439 */
440 BUFFER_TRACE(bitmap_bh, "set in b_committed_data");
441 J_ASSERT_BH(bitmap_bh,
442 bh2jh(bitmap_bh)->b_committed_data != NULL);
443 ext3_set_bit_atomic(sb_bgl_lock(sbi, block_group), bit + i,
444 bh2jh(bitmap_bh)->b_committed_data);
445
446 /*
447 * We clear the bit in the bitmap after setting the committed
448 * data bit, because this is the reverse order to that which
449 * the allocator uses.
450 */
451 BUFFER_TRACE(bitmap_bh, "clear bit");
452 if (!ext3_clear_bit_atomic(sb_bgl_lock(sbi, block_group),
453 bit + i, bitmap_bh->b_data)) {
454 jbd_unlock_bh_state(bitmap_bh);
455 ext3_error(sb, __FUNCTION__,
456 "bit already cleared for block %lu", block + i);
457 jbd_lock_bh_state(bitmap_bh);
458 BUFFER_TRACE(bitmap_bh, "bit already cleared");
459 } else {
460 group_freed++;
461 }
462 }
463 jbd_unlock_bh_state(bitmap_bh);
464
465 spin_lock(sb_bgl_lock(sbi, block_group));
466 desc->bg_free_blocks_count =
467 cpu_to_le16(le16_to_cpu(desc->bg_free_blocks_count) +
468 group_freed);
469 spin_unlock(sb_bgl_lock(sbi, block_group));
470 percpu_counter_mod(&sbi->s_freeblocks_counter, count);
471
472 /* We dirtied the bitmap block */
473 BUFFER_TRACE(bitmap_bh, "dirtied bitmap block");
474 err = ext3_journal_dirty_metadata(handle, bitmap_bh);
475
476 /* And the group descriptor block */
477 BUFFER_TRACE(gd_bh, "dirtied group descriptor block");
478 ret = ext3_journal_dirty_metadata(handle, gd_bh);
479 if (!err) err = ret;
480 *pdquot_freed_blocks += group_freed;
481
482 if (overflow && !err) {
483 block += count;
484 count = overflow;
485 goto do_more;
486 }
487 sb->s_dirt = 1;
488error_return:
489 brelse(bitmap_bh);
490 ext3_std_error(sb, err);
491 return;
492}
493
494/* Free given blocks, update quota and i_blocks field */
495void ext3_free_blocks(handle_t *handle, struct inode *inode,
496 unsigned long block, unsigned long count)
497{
498 struct super_block * sb;
499 int dquot_freed_blocks;
500
501 sb = inode->i_sb;
502 if (!sb) {
503 printk ("ext3_free_blocks: nonexistent device");
504 return;
505 }
506 ext3_free_blocks_sb(handle, sb, block, count, &dquot_freed_blocks);
507 if (dquot_freed_blocks)
508 DQUOT_FREE_BLOCK(inode, dquot_freed_blocks);
509 return;
510}
511
512/*
513 * For ext3 allocations, we must not reuse any blocks which are
514 * allocated in the bitmap buffer's "last committed data" copy. This
515 * prevents deletes from freeing up the page for reuse until we have
516 * committed the delete transaction.
517 *
518 * If we didn't do this, then deleting something and reallocating it as
519 * data would allow the old block to be overwritten before the
520 * transaction committed (because we force data to disk before commit).
521 * This would lead to corruption if we crashed between overwriting the
522 * data and committing the delete.
523 *
524 * @@@ We may want to make this allocation behaviour conditional on
525 * data-writes at some point, and disable it for metadata allocations or
526 * sync-data inodes.
527 */
528static int ext3_test_allocatable(int nr, struct buffer_head *bh)
529{
530 int ret;
531 struct journal_head *jh = bh2jh(bh);
532
533 if (ext3_test_bit(nr, bh->b_data))
534 return 0;
535
536 jbd_lock_bh_state(bh);
537 if (!jh->b_committed_data)
538 ret = 1;
539 else
540 ret = !ext3_test_bit(nr, jh->b_committed_data);
541 jbd_unlock_bh_state(bh);
542 return ret;
543}
544
545static int
546bitmap_search_next_usable_block(int start, struct buffer_head *bh,
547 int maxblocks)
548{
549 int next;
550 struct journal_head *jh = bh2jh(bh);
551
552 /*
553 * The bitmap search --- search forward alternately through the actual
554 * bitmap and the last-committed copy until we find a bit free in
555 * both
556 */
557 while (start < maxblocks) {
558 next = ext3_find_next_zero_bit(bh->b_data, maxblocks, start);
559 if (next >= maxblocks)
560 return -1;
561 if (ext3_test_allocatable(next, bh))
562 return next;
563 jbd_lock_bh_state(bh);
564 if (jh->b_committed_data)
565 start = ext3_find_next_zero_bit(jh->b_committed_data,
566 maxblocks, next);
567 jbd_unlock_bh_state(bh);
568 }
569 return -1;
570}
571
572/*
573 * Find an allocatable block in a bitmap. We honour both the bitmap and
574 * its last-committed copy (if that exists), and perform the "most
575 * appropriate allocation" algorithm of looking for a free block near
576 * the initial goal; then for a free byte somewhere in the bitmap; then
577 * for any free bit in the bitmap.
578 */
579static int
580find_next_usable_block(int start, struct buffer_head *bh, int maxblocks)
581{
582 int here, next;
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 */
594 int end_goal = (start + 63) & ~63;
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 */
630static inline int
631claim_block(spinlock_t *lock, int block, struct buffer_head *bh)
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 */
654static int
655ext3_try_to_allocate(struct super_block *sb, handle_t *handle, int group,
Mingming Caob54e41e2006-03-26 01:37:57 -0800656 struct buffer_head *bitmap_bh, int goal,
657 unsigned long *count, struct ext3_reserve_window *my_rsv)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700658{
659 int group_first_block, start, end;
Mingming Caob54e41e2006-03-26 01:37:57 -0800660 unsigned long num = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700661
662 /* we do allocation within the reservation window if we have a window */
663 if (my_rsv) {
664 group_first_block =
665 le32_to_cpu(EXT3_SB(sb)->s_es->s_first_data_block) +
666 group * EXT3_BLOCKS_PER_GROUP(sb);
667 if (my_rsv->_rsv_start >= group_first_block)
668 start = my_rsv->_rsv_start - group_first_block;
669 else
670 /* reservation window cross group boundary */
671 start = 0;
672 end = my_rsv->_rsv_end - group_first_block + 1;
673 if (end > EXT3_BLOCKS_PER_GROUP(sb))
674 /* reservation window crosses group boundary */
675 end = EXT3_BLOCKS_PER_GROUP(sb);
676 if ((start <= goal) && (goal < end))
677 start = goal;
678 else
679 goal = -1;
680 } else {
681 if (goal > 0)
682 start = goal;
683 else
684 start = 0;
685 end = EXT3_BLOCKS_PER_GROUP(sb);
686 }
687
688 BUG_ON(start > EXT3_BLOCKS_PER_GROUP(sb));
689
690repeat:
691 if (goal < 0 || !ext3_test_allocatable(goal, bitmap_bh)) {
692 goal = find_next_usable_block(start, bitmap_bh, end);
693 if (goal < 0)
694 goto fail_access;
695 if (!my_rsv) {
696 int i;
697
698 for (i = 0; i < 7 && goal > start &&
699 ext3_test_allocatable(goal - 1,
700 bitmap_bh);
701 i++, goal--)
702 ;
703 }
704 }
705 start = goal;
706
707 if (!claim_block(sb_bgl_lock(EXT3_SB(sb), group), goal, bitmap_bh)) {
708 /*
709 * The block was allocated by another thread, or it was
710 * allocated and then freed by another thread
711 */
712 start++;
713 goal++;
714 if (start >= end)
715 goto fail_access;
716 goto repeat;
717 }
Mingming Caob54e41e2006-03-26 01:37:57 -0800718 num++;
719 goal++;
720 while (num < *count && goal < end
721 && ext3_test_allocatable(goal, bitmap_bh)
722 && claim_block(sb_bgl_lock(EXT3_SB(sb), group), goal, bitmap_bh)) {
723 num++;
724 goal++;
725 }
726 *count = num;
727 return goal - num;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700728fail_access:
Mingming Caob54e41e2006-03-26 01:37:57 -0800729 *count = num;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700730 return -1;
731}
732
733/**
734 * find_next_reservable_window():
735 * find a reservable space within the given range.
736 * It does not allocate the reservation window for now:
737 * alloc_new_reservation() will do the work later.
738 *
739 * @search_head: the head of the searching list;
740 * This is not necessarily the list head of the whole filesystem
741 *
742 * We have both head and start_block to assist the search
743 * for the reservable space. The list starts from head,
744 * but we will shift to the place where start_block is,
745 * then start from there, when looking for a reservable space.
746 *
747 * @size: the target new reservation window size
748 *
749 * @group_first_block: the first block we consider to start
750 * the real search from
751 *
752 * @last_block:
753 * the maximum block number that our goal reservable space
754 * could start from. This is normally the last block in this
755 * group. The search will end when we found the start of next
756 * possible reservable space is out of this boundary.
757 * This could handle the cross boundary reservation window
758 * request.
759 *
760 * basically we search from the given range, rather than the whole
761 * reservation double linked list, (start_block, last_block)
762 * to find a free region that is of my size and has not
763 * been reserved.
764 *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700765 */
Mingming Cao21fe3472005-06-28 20:45:16 -0700766static int find_next_reservable_window(
Linus Torvalds1da177e2005-04-16 15:20:36 -0700767 struct ext3_reserve_window_node *search_head,
Mingming Cao21fe3472005-06-28 20:45:16 -0700768 struct ext3_reserve_window_node *my_rsv,
769 struct super_block * sb, int start_block,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700770 int last_block)
771{
772 struct rb_node *next;
773 struct ext3_reserve_window_node *rsv, *prev;
774 int cur;
Mingming Cao21fe3472005-06-28 20:45:16 -0700775 int size = my_rsv->rsv_goal_size;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700776
777 /* TODO: make the start of the reservation window byte-aligned */
778 /* cur = *start_block & ~7;*/
Mingming Cao21fe3472005-06-28 20:45:16 -0700779 cur = start_block;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700780 rsv = search_head;
781 if (!rsv)
Mingming Cao21fe3472005-06-28 20:45:16 -0700782 return -1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700783
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)
Mingming Cao21fe3472005-06-28 20:45:16 -0700798 return -1; /* fail */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700799
800 prev = rsv;
801 next = rb_next(&rsv->rsv_node);
Mingming Cao21fe3472005-06-28 20:45:16 -0700802 rsv = list_entry(next,struct ext3_reserve_window_node,rsv_node);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700803
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 */
Mingming Cao21fe3472005-06-28 20:45:16 -0700829
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;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700848}
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 *
876 * @goal: The goal (group-relative). It is where the search for a
877 * free reservable space should start from.
878 * if we have a goal(goal >0 ), then start from there,
879 * no goal(goal = -1), we start from the first block
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
Mingming Cao21fe3472005-06-28 20:45:16 -0700885 *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700886 */
887static int alloc_new_reservation(struct ext3_reserve_window_node *my_rsv,
888 int goal, struct super_block *sb,
889 unsigned int group, struct buffer_head *bitmap_bh)
890{
891 struct ext3_reserve_window_node *search_head;
892 int group_first_block, group_end_block, start_block;
893 int first_free_block;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700894 struct rb_root *fs_rsv_root = &EXT3_SB(sb)->s_rsv_window_root;
895 unsigned long size;
Mingming Cao21fe3472005-06-28 20:45:16 -0700896 int ret;
897 spinlock_t *rsv_lock = &EXT3_SB(sb)->s_rsv_window_lock;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700898
899 group_first_block = le32_to_cpu(EXT3_SB(sb)->s_es->s_first_data_block) +
900 group * EXT3_BLOCKS_PER_GROUP(sb);
901 group_end_block = group_first_block + EXT3_BLOCKS_PER_GROUP(sb) - 1;
902
903 if (goal < 0)
904 start_block = group_first_block;
905 else
906 start_block = goal + group_first_block;
907
908 size = my_rsv->rsv_goal_size;
Mingming Cao21fe3472005-06-28 20:45:16 -0700909
Linus Torvalds1da177e2005-04-16 15:20:36 -0700910 if (!rsv_is_empty(&my_rsv->rsv_window)) {
911 /*
912 * if the old reservation is cross group boundary
913 * and if the goal is inside the old reservation window,
914 * we will come here when we just failed to allocate from
915 * the first part of the window. We still have another part
916 * that belongs to the next group. In this case, there is no
917 * point to discard our window and try to allocate a new one
918 * in this group(which will fail). we should
919 * keep the reservation window, just simply move on.
920 *
921 * Maybe we could shift the start block of the reservation
922 * window to the first block of next group.
923 */
924
925 if ((my_rsv->rsv_start <= group_end_block) &&
926 (my_rsv->rsv_end > group_end_block) &&
927 (start_block >= my_rsv->rsv_start))
928 return -1;
929
930 if ((my_rsv->rsv_alloc_hit >
931 (my_rsv->rsv_end - my_rsv->rsv_start + 1) / 2)) {
932 /*
933 * if we previously allocation hit ration is greater than half
934 * we double the size of reservation window next time
935 * otherwise keep the same
936 */
937 size = size * 2;
938 if (size > EXT3_MAX_RESERVE_BLOCKS)
939 size = EXT3_MAX_RESERVE_BLOCKS;
940 my_rsv->rsv_goal_size= size;
941 }
942 }
Mingming Cao21fe3472005-06-28 20:45:16 -0700943
944 spin_lock(rsv_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700945 /*
946 * shift the search start to the window near the goal block
947 */
948 search_head = search_reserve_window(fs_rsv_root, start_block);
949
950 /*
951 * find_next_reservable_window() simply finds a reservable window
952 * inside the given range(start_block, group_end_block).
953 *
954 * To make sure the reservation window has a free bit inside it, we
955 * need to check the bitmap after we found a reservable window.
956 */
957retry:
Mingming Cao21fe3472005-06-28 20:45:16 -0700958 ret = find_next_reservable_window(search_head, my_rsv, sb,
959 start_block, group_end_block);
960
961 if (ret == -1) {
962 if (!rsv_is_empty(&my_rsv->rsv_window))
963 rsv_window_remove(sb, my_rsv);
964 spin_unlock(rsv_lock);
965 return -1;
966 }
967
Linus Torvalds1da177e2005-04-16 15:20:36 -0700968 /*
969 * On success, find_next_reservable_window() returns the
970 * reservation window where there is a reservable space after it.
971 * Before we reserve this reservable space, we need
972 * to make sure there is at least a free block inside this region.
973 *
974 * searching the first free bit on the block bitmap and copy of
975 * last committed bitmap alternatively, until we found a allocatable
976 * block. Search start from the start block of the reservable space
977 * we just found.
978 */
Mingming Cao21fe3472005-06-28 20:45:16 -0700979 spin_unlock(rsv_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700980 first_free_block = bitmap_search_next_usable_block(
Mingming Cao21fe3472005-06-28 20:45:16 -0700981 my_rsv->rsv_start - group_first_block,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700982 bitmap_bh, group_end_block - group_first_block + 1);
983
984 if (first_free_block < 0) {
985 /*
986 * no free block left on the bitmap, no point
987 * to reserve the space. return failed.
988 */
Mingming Cao21fe3472005-06-28 20:45:16 -0700989 spin_lock(rsv_lock);
990 if (!rsv_is_empty(&my_rsv->rsv_window))
991 rsv_window_remove(sb, my_rsv);
992 spin_unlock(rsv_lock);
993 return -1; /* failed */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700994 }
Mingming Cao21fe3472005-06-28 20:45:16 -0700995
Linus Torvalds1da177e2005-04-16 15:20:36 -0700996 start_block = first_free_block + group_first_block;
997 /*
998 * check if the first free block is within the
Mingming Cao21fe3472005-06-28 20:45:16 -0700999 * free space we just reserved
Linus Torvalds1da177e2005-04-16 15:20:36 -07001000 */
Mingming Cao21fe3472005-06-28 20:45:16 -07001001 if (start_block >= my_rsv->rsv_start && start_block < my_rsv->rsv_end)
1002 return 0; /* success */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001003 /*
1004 * if the first free bit we found is out of the reservable space
Mingming Cao21fe3472005-06-28 20:45:16 -07001005 * continue search for next reservable space,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001006 * start from where the free block is,
1007 * we also shift the list head to where we stopped last time
1008 */
Mingming Cao21fe3472005-06-28 20:45:16 -07001009 search_head = my_rsv;
1010 spin_lock(rsv_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001011 goto retry;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001012}
1013
Mingming Caod48589b2006-03-26 01:37:59 -08001014static void try_to_extend_reservation(struct ext3_reserve_window_node *my_rsv,
1015 struct super_block *sb, int size)
1016{
1017 struct ext3_reserve_window_node *next_rsv;
1018 struct rb_node *next;
1019 spinlock_t *rsv_lock = &EXT3_SB(sb)->s_rsv_window_lock;
1020
1021 if (!spin_trylock(rsv_lock))
1022 return;
1023
1024 next = rb_next(&my_rsv->rsv_node);
1025
1026 if (!next)
1027 my_rsv->rsv_end += size;
1028 else {
1029 next_rsv = list_entry(next, struct ext3_reserve_window_node, rsv_node);
1030
1031 if ((next_rsv->rsv_start - my_rsv->rsv_end - 1) >= size)
1032 my_rsv->rsv_end += size;
1033 else
1034 my_rsv->rsv_end = next_rsv->rsv_start - 1;
1035 }
1036 spin_unlock(rsv_lock);
1037}
1038
Linus Torvalds1da177e2005-04-16 15:20:36 -07001039/*
1040 * This is the main function used to allocate a new block and its reservation
1041 * window.
1042 *
1043 * Each time when a new block allocation is need, first try to allocate from
1044 * its own reservation. If it does not have a reservation window, instead of
1045 * looking for a free bit on bitmap first, then look up the reservation list to
1046 * see if it is inside somebody else's reservation window, we try to allocate a
1047 * reservation window for it starting from the goal first. Then do the block
1048 * allocation within the reservation window.
1049 *
1050 * This will avoid keeping on searching the reservation list again and
Glauber de Oliveira Costa5b116872005-10-30 15:02:48 -08001051 * again when somebody is looking for a free block (without
Linus Torvalds1da177e2005-04-16 15:20:36 -07001052 * reservation), and there are lots of free blocks, but they are all
1053 * being reserved.
1054 *
1055 * We use a sorted double linked list for the per-filesystem reservation list.
1056 * The insert, remove and find a free space(non-reserved) operations for the
1057 * sorted double linked list should be fast.
1058 *
1059 */
1060static int
1061ext3_try_to_allocate_with_rsv(struct super_block *sb, handle_t *handle,
1062 unsigned int group, struct buffer_head *bitmap_bh,
1063 int goal, struct ext3_reserve_window_node * my_rsv,
Mingming Caob54e41e2006-03-26 01:37:57 -08001064 unsigned long *count, int *errp)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001065{
Linus Torvalds1da177e2005-04-16 15:20:36 -07001066 unsigned long group_first_block;
1067 int ret = 0;
1068 int fatal;
Mingming Caob54e41e2006-03-26 01:37:57 -08001069 unsigned long num = *count;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001070
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 ) {
Mingming Caob54e41e2006-03-26 01:37:57 -08001092 ret = ext3_try_to_allocate(sb, handle, group, bitmap_bh,
1093 goal, count, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001094 goto out;
1095 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001096 /*
1097 * goal is a group relative block number (if there is a goal)
1098 * 0 < goal < EXT3_BLOCKS_PER_GROUP(sb)
1099 * first block is a filesystem wide block number
1100 * first block is the block number of the first block in this group
1101 */
1102 group_first_block = le32_to_cpu(EXT3_SB(sb)->s_es->s_first_data_block) +
1103 group * EXT3_BLOCKS_PER_GROUP(sb);
1104
1105 /*
1106 * Basically we will allocate a new block from inode's reservation
1107 * window.
1108 *
1109 * We need to allocate a new reservation window, if:
1110 * a) inode does not have a reservation window; or
1111 * b) last attempt to allocate a block from existing reservation
1112 * failed; or
1113 * c) we come here with a goal and with a reservation window
1114 *
1115 * We do not need to allocate a new reservation window if we come here
1116 * at the beginning with a goal and the goal is inside the window, or
1117 * we don't have a goal but already have a reservation window.
1118 * then we could go to allocate from the reservation window directly.
1119 */
1120 while (1) {
Mingming Cao21fe3472005-06-28 20:45:16 -07001121 if (rsv_is_empty(&my_rsv->rsv_window) || (ret < 0) ||
1122 !goal_in_my_reservation(&my_rsv->rsv_window, goal, group, sb)) {
Mingming Caod48589b2006-03-26 01:37:59 -08001123 if (my_rsv->rsv_goal_size < *count)
1124 my_rsv->rsv_goal_size = *count;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001125 ret = alloc_new_reservation(my_rsv, goal, sb,
1126 group, bitmap_bh);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001127 if (ret < 0)
1128 break; /* failed */
1129
Mingming Cao21fe3472005-06-28 20:45:16 -07001130 if (!goal_in_my_reservation(&my_rsv->rsv_window, goal, group, sb))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001131 goal = -1;
Mingming Caod48589b2006-03-26 01:37:59 -08001132 } else if (goal > 0 && (my_rsv->rsv_end-goal+1) < *count)
1133 try_to_extend_reservation(my_rsv, sb,
1134 *count-my_rsv->rsv_end + goal - 1);
1135
Mingming Cao21fe3472005-06-28 20:45:16 -07001136 if ((my_rsv->rsv_start >= group_first_block + EXT3_BLOCKS_PER_GROUP(sb))
1137 || (my_rsv->rsv_end < group_first_block))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001138 BUG();
1139 ret = ext3_try_to_allocate(sb, handle, group, bitmap_bh, goal,
Mingming Caob54e41e2006-03-26 01:37:57 -08001140 &num, &my_rsv->rsv_window);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001141 if (ret >= 0) {
Mingming Caob54e41e2006-03-26 01:37:57 -08001142 my_rsv->rsv_alloc_hit += num;
1143 *count = num;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001144 break; /* succeed */
1145 }
Mingming Caob54e41e2006-03-26 01:37:57 -08001146 num = *count;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001147 }
1148out:
1149 if (ret >= 0) {
1150 BUFFER_TRACE(bitmap_bh, "journal_dirty_metadata for "
1151 "bitmap block");
1152 fatal = ext3_journal_dirty_metadata(handle, bitmap_bh);
1153 if (fatal) {
1154 *errp = fatal;
1155 return -1;
1156 }
1157 return ret;
1158 }
1159
1160 BUFFER_TRACE(bitmap_bh, "journal_release_buffer");
1161 ext3_journal_release_buffer(handle, bitmap_bh);
1162 return ret;
1163}
1164
1165static int ext3_has_free_blocks(struct ext3_sb_info *sbi)
1166{
1167 int free_blocks, root_blocks;
1168
1169 free_blocks = percpu_counter_read_positive(&sbi->s_freeblocks_counter);
1170 root_blocks = le32_to_cpu(sbi->s_es->s_r_blocks_count);
1171 if (free_blocks < root_blocks + 1 && !capable(CAP_SYS_RESOURCE) &&
1172 sbi->s_resuid != current->fsuid &&
1173 (sbi->s_resgid == 0 || !in_group_p (sbi->s_resgid))) {
1174 return 0;
1175 }
1176 return 1;
1177}
1178
1179/*
1180 * ext3_should_retry_alloc() is called when ENOSPC is returned, and if
1181 * it is profitable to retry the operation, this function will wait
1182 * for the current or commiting transaction to complete, and then
1183 * return TRUE.
1184 */
1185int ext3_should_retry_alloc(struct super_block *sb, int *retries)
1186{
1187 if (!ext3_has_free_blocks(EXT3_SB(sb)) || (*retries)++ > 3)
1188 return 0;
1189
1190 jbd_debug(1, "%s: retrying operation after ENOSPC\n", sb->s_id);
1191
1192 return journal_force_commit_nested(EXT3_SB(sb)->s_journal);
1193}
1194
1195/*
1196 * ext3_new_block uses a goal block to assist allocation. If the goal is
1197 * free, or there is a free block within 32 blocks of the goal, that block
1198 * is allocated. Otherwise a forward search is made for a free block; within
1199 * each block group the search first looks for an entire free byte in the block
1200 * bitmap, and then for any free bit if that fails.
1201 * This function also updates quota and i_blocks field.
1202 */
Mingming Caob54e41e2006-03-26 01:37:57 -08001203int ext3_new_blocks(handle_t *handle, struct inode *inode,
1204 unsigned long goal, unsigned long *count, int *errp)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001205{
1206 struct buffer_head *bitmap_bh = NULL;
1207 struct buffer_head *gdp_bh;
1208 int group_no;
1209 int goal_group;
1210 int ret_block;
1211 int bgi; /* blockgroup iteration index */
1212 int target_block;
1213 int fatal = 0, err;
1214 int performed_allocation = 0;
1215 int free_blocks;
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;
Mingming Caob54e41e2006-03-26 01:37:57 -08001227 unsigned long num = *count;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001228
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 */
Mingming Caofaa56972006-03-26 01:37:58 -08001239 if (DQUOT_ALLOC_BLOCK(inode, num)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001240 *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;
1277retry:
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) {
1288 ret_block = ((goal - le32_to_cpu(es->s_first_data_block)) %
1289 EXT3_BLOCKS_PER_GROUP(sb));
1290 bitmap_bh = read_block_bitmap(sb, group_no);
1291 if (!bitmap_bh)
1292 goto io_error;
1293 ret_block = ext3_try_to_allocate_with_rsv(sb, handle, group_no,
Mingming Caob54e41e2006-03-26 01:37:57 -08001294 bitmap_bh, ret_block, my_rsv, &num, &fatal);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001295 if (fatal)
1296 goto out;
1297 if (ret_block >= 0)
1298 goto allocated;
1299 }
1300
1301 ngroups = EXT3_SB(sb)->s_groups_count;
1302 smp_rmb();
1303
1304 /*
1305 * Now search the rest of the groups. We assume that
1306 * i and gdp correctly point to the last group visited.
1307 */
1308 for (bgi = 0; bgi < ngroups; bgi++) {
1309 group_no++;
1310 if (group_no >= ngroups)
1311 group_no = 0;
1312 gdp = ext3_get_group_desc(sb, group_no, &gdp_bh);
1313 if (!gdp) {
1314 *errp = -EIO;
1315 goto out;
1316 }
1317 free_blocks = le16_to_cpu(gdp->bg_free_blocks_count);
1318 /*
1319 * skip this group if the number of
1320 * free blocks is less than half of the reservation
1321 * window size.
1322 */
1323 if (free_blocks <= (windowsz/2))
1324 continue;
1325
1326 brelse(bitmap_bh);
1327 bitmap_bh = read_block_bitmap(sb, group_no);
1328 if (!bitmap_bh)
1329 goto io_error;
1330 ret_block = ext3_try_to_allocate_with_rsv(sb, handle, group_no,
Mingming Caob54e41e2006-03-26 01:37:57 -08001331 bitmap_bh, -1, my_rsv, &num, &fatal);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001332 if (fatal)
1333 goto out;
1334 if (ret_block >= 0)
1335 goto allocated;
1336 }
1337 /*
1338 * We may end up a bogus ealier ENOSPC error due to
1339 * filesystem is "full" of reservations, but
1340 * there maybe indeed free blocks avaliable on disk
1341 * In this case, we just forget about the reservations
1342 * just do block allocation as without reservations.
1343 */
1344 if (my_rsv) {
1345 my_rsv = NULL;
1346 group_no = goal_group;
1347 goto retry;
1348 }
1349 /* No space left on the device */
1350 *errp = -ENOSPC;
1351 goto out;
1352
1353allocated:
1354
1355 ext3_debug("using block group %d(%d)\n",
1356 group_no, gdp->bg_free_blocks_count);
1357
1358 BUFFER_TRACE(gdp_bh, "get_write_access");
1359 fatal = ext3_journal_get_write_access(handle, gdp_bh);
1360 if (fatal)
1361 goto out;
1362
1363 target_block = ret_block + group_no * EXT3_BLOCKS_PER_GROUP(sb)
1364 + le32_to_cpu(es->s_first_data_block);
1365
Mingming Caofaa56972006-03-26 01:37:58 -08001366 if (in_range(le32_to_cpu(gdp->bg_block_bitmap), target_block, num) ||
1367 in_range(le32_to_cpu(gdp->bg_inode_bitmap), target_block, num) ||
Linus Torvalds1da177e2005-04-16 15:20:36 -07001368 in_range(target_block, le32_to_cpu(gdp->bg_inode_table),
Mingming Caofaa56972006-03-26 01:37:58 -08001369 EXT3_SB(sb)->s_itb_per_group) ||
1370 in_range(target_block + num - 1, le32_to_cpu(gdp->bg_inode_table),
Linus Torvalds1da177e2005-04-16 15:20:36 -07001371 EXT3_SB(sb)->s_itb_per_group))
1372 ext3_error(sb, "ext3_new_block",
1373 "Allocating block in system zone - "
Mingming Caofaa56972006-03-26 01:37:58 -08001374 "blocks from %u, length %lu", target_block, num);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001375
1376 performed_allocation = 1;
1377
1378#ifdef CONFIG_JBD_DEBUG
1379 {
1380 struct buffer_head *debug_bh;
1381
1382 /* Record bitmap buffer state in the newly allocated block */
1383 debug_bh = sb_find_get_block(sb, target_block);
1384 if (debug_bh) {
1385 BUFFER_TRACE(debug_bh, "state when allocated");
1386 BUFFER_TRACE2(debug_bh, bitmap_bh, "bitmap state");
1387 brelse(debug_bh);
1388 }
1389 }
1390 jbd_lock_bh_state(bitmap_bh);
1391 spin_lock(sb_bgl_lock(sbi, group_no));
1392 if (buffer_jbd(bitmap_bh) && bh2jh(bitmap_bh)->b_committed_data) {
Mingming Caofaa56972006-03-26 01:37:58 -08001393 int i;
1394
1395 for (i = 0; i < num; i++) {
1396 if (ext3_test_bit(ret_block,
1397 bh2jh(bitmap_bh)->b_committed_data)) {
1398 printk("%s: block was unexpectedly set in "
1399 "b_committed_data\n", __FUNCTION__);
1400 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001401 }
1402 }
1403 ext3_debug("found bit %d\n", ret_block);
1404 spin_unlock(sb_bgl_lock(sbi, group_no));
1405 jbd_unlock_bh_state(bitmap_bh);
1406#endif
1407
1408 /* ret_block was blockgroup-relative. Now it becomes fs-relative */
1409 ret_block = target_block;
1410
Mingming Caofaa56972006-03-26 01:37:58 -08001411 if (ret_block + num - 1 >= le32_to_cpu(es->s_blocks_count)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001412 ext3_error(sb, "ext3_new_block",
1413 "block(%d) >= blocks count(%d) - "
1414 "block_group = %d, es == %p ", ret_block,
1415 le32_to_cpu(es->s_blocks_count), group_no, es);
1416 goto out;
1417 }
1418
1419 /*
1420 * It is up to the caller to add the new buffer to a journal
1421 * list of some description. We don't know in advance whether
1422 * the caller wants to use it as metadata or data.
1423 */
1424 ext3_debug("allocating block %d. Goal hits %d of %d.\n",
1425 ret_block, goal_hits, goal_attempts);
1426
1427 spin_lock(sb_bgl_lock(sbi, group_no));
1428 gdp->bg_free_blocks_count =
Mingming Caofaa56972006-03-26 01:37:58 -08001429 cpu_to_le16(le16_to_cpu(gdp->bg_free_blocks_count) - num);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001430 spin_unlock(sb_bgl_lock(sbi, group_no));
Mingming Caofaa56972006-03-26 01:37:58 -08001431 percpu_counter_mod(&sbi->s_freeblocks_counter, -num);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001432
1433 BUFFER_TRACE(gdp_bh, "journal_dirty_metadata for group descriptor");
1434 err = ext3_journal_dirty_metadata(handle, gdp_bh);
1435 if (!fatal)
1436 fatal = err;
1437
1438 sb->s_dirt = 1;
1439 if (fatal)
1440 goto out;
1441
1442 *errp = 0;
1443 brelse(bitmap_bh);
Mingming Caofaa56972006-03-26 01:37:58 -08001444 DQUOT_FREE_BLOCK(inode, *count-num);
Mingming Caob54e41e2006-03-26 01:37:57 -08001445 *count = num;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001446 return ret_block;
1447
1448io_error:
1449 *errp = -EIO;
1450out:
1451 if (fatal) {
1452 *errp = fatal;
1453 ext3_std_error(sb, fatal);
1454 }
1455 /*
1456 * Undo the block allocation
1457 */
1458 if (!performed_allocation)
Mingming Caofaa56972006-03-26 01:37:58 -08001459 DQUOT_FREE_BLOCK(inode, *count);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001460 brelse(bitmap_bh);
1461 return 0;
1462}
1463
Mingming Caob54e41e2006-03-26 01:37:57 -08001464int ext3_new_block(handle_t *handle, struct inode *inode,
1465 unsigned long goal, int *errp)
1466{
1467 unsigned long count = 1;
1468
1469 return ext3_new_blocks(handle, inode, goal, &count, errp);
1470}
1471
Linus Torvalds1da177e2005-04-16 15:20:36 -07001472unsigned long ext3_count_free_blocks(struct super_block *sb)
1473{
1474 unsigned long desc_count;
1475 struct ext3_group_desc *gdp;
1476 int i;
Glauber de Oliveira Costa8bdac5d2005-09-22 21:44:26 -07001477 unsigned long ngroups = EXT3_SB(sb)->s_groups_count;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001478#ifdef EXT3FS_DEBUG
1479 struct ext3_super_block *es;
1480 unsigned long bitmap_count, x;
1481 struct buffer_head *bitmap_bh = NULL;
1482
Linus Torvalds1da177e2005-04-16 15:20:36 -07001483 es = EXT3_SB(sb)->s_es;
1484 desc_count = 0;
1485 bitmap_count = 0;
1486 gdp = NULL;
Glauber de Oliveira Costa8bdac5d2005-09-22 21:44:26 -07001487
Glauber de Oliveira Costa5b116872005-10-30 15:02:48 -08001488 smp_rmb();
Glauber de Oliveira Costa8bdac5d2005-09-22 21:44:26 -07001489 for (i = 0; i < ngroups; i++) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001490 gdp = ext3_get_group_desc(sb, i, NULL);
1491 if (!gdp)
1492 continue;
1493 desc_count += le16_to_cpu(gdp->bg_free_blocks_count);
1494 brelse(bitmap_bh);
1495 bitmap_bh = read_block_bitmap(sb, i);
1496 if (bitmap_bh == NULL)
1497 continue;
1498
1499 x = ext3_count_free(bitmap_bh, sb->s_blocksize);
1500 printk("group %d: stored = %d, counted = %lu\n",
1501 i, le16_to_cpu(gdp->bg_free_blocks_count), x);
1502 bitmap_count += x;
1503 }
1504 brelse(bitmap_bh);
1505 printk("ext3_count_free_blocks: stored = %u, computed = %lu, %lu\n",
1506 le32_to_cpu(es->s_free_blocks_count), desc_count, bitmap_count);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001507 return bitmap_count;
1508#else
1509 desc_count = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001510 smp_rmb();
1511 for (i = 0; i < ngroups; i++) {
1512 gdp = ext3_get_group_desc(sb, i, NULL);
1513 if (!gdp)
1514 continue;
1515 desc_count += le16_to_cpu(gdp->bg_free_blocks_count);
1516 }
1517
1518 return desc_count;
1519#endif
1520}
1521
1522static inline int
1523block_in_use(unsigned long block, struct super_block *sb, unsigned char *map)
1524{
1525 return ext3_test_bit ((block -
1526 le32_to_cpu(EXT3_SB(sb)->s_es->s_first_data_block)) %
1527 EXT3_BLOCKS_PER_GROUP(sb), map);
1528}
1529
1530static inline int test_root(int a, int b)
1531{
1532 int num = b;
1533
1534 while (a > num)
1535 num *= b;
1536 return num == a;
1537}
1538
1539static int ext3_group_sparse(int group)
1540{
1541 if (group <= 1)
1542 return 1;
1543 if (!(group & 1))
1544 return 0;
1545 return (test_root(group, 7) || test_root(group, 5) ||
1546 test_root(group, 3));
1547}
1548
1549/**
1550 * ext3_bg_has_super - number of blocks used by the superblock in group
1551 * @sb: superblock for filesystem
1552 * @group: group number to check
1553 *
1554 * Return the number of blocks used by the superblock (primary or backup)
1555 * in this group. Currently this will be only 0 or 1.
1556 */
1557int ext3_bg_has_super(struct super_block *sb, int group)
1558{
Glauber de Oliveira Costab5a7c4f2006-03-24 03:18:37 -08001559 if (EXT3_HAS_RO_COMPAT_FEATURE(sb,
1560 EXT3_FEATURE_RO_COMPAT_SPARSE_SUPER) &&
1561 !ext3_group_sparse(group))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001562 return 0;
1563 return 1;
1564}
1565
Glauber de Oliveira Costab5a7c4f2006-03-24 03:18:37 -08001566static unsigned long ext3_bg_num_gdb_meta(struct super_block *sb, int group)
1567{
1568 unsigned long metagroup = group / EXT3_DESC_PER_BLOCK(sb);
1569 unsigned long first = metagroup * EXT3_DESC_PER_BLOCK(sb);
1570 unsigned long last = first + EXT3_DESC_PER_BLOCK(sb) - 1;
1571
1572 if (group == first || group == first + 1 || group == last)
1573 return 1;
1574 return 0;
1575}
1576
1577static unsigned long ext3_bg_num_gdb_nometa(struct super_block *sb, int group)
1578{
1579 if (EXT3_HAS_RO_COMPAT_FEATURE(sb,
1580 EXT3_FEATURE_RO_COMPAT_SPARSE_SUPER) &&
1581 !ext3_group_sparse(group))
1582 return 0;
1583 return EXT3_SB(sb)->s_gdb_count;
1584}
1585
Linus Torvalds1da177e2005-04-16 15:20:36 -07001586/**
1587 * ext3_bg_num_gdb - number of blocks used by the group table in group
1588 * @sb: superblock for filesystem
1589 * @group: group number to check
1590 *
1591 * Return the number of blocks used by the group descriptor table
1592 * (primary or backup) in this group. In the future there may be a
1593 * different number of descriptor blocks in each group.
1594 */
1595unsigned long ext3_bg_num_gdb(struct super_block *sb, int group)
1596{
Glauber de Oliveira Costab5a7c4f2006-03-24 03:18:37 -08001597 unsigned long first_meta_bg =
1598 le32_to_cpu(EXT3_SB(sb)->s_es->s_first_meta_bg);
1599 unsigned long metagroup = group / EXT3_DESC_PER_BLOCK(sb);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001600
Glauber de Oliveira Costab5a7c4f2006-03-24 03:18:37 -08001601 if (!EXT3_HAS_INCOMPAT_FEATURE(sb,EXT3_FEATURE_INCOMPAT_META_BG) ||
1602 metagroup < first_meta_bg)
1603 return ext3_bg_num_gdb_nometa(sb,group);
1604
1605 return ext3_bg_num_gdb_meta(sb,group);
1606
1607}