2 * linux/fs/ext3/balloc.c
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)
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
14 #include <linux/time.h>
15 #include <linux/capability.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 #include <linux/vs_base.h>
23 #include <linux/vs_dlimit.h>
26 * balloc.c contains the blocks allocation and deallocation routines
30 * The free blocks are managed by bitmaps. A file system contains several
31 * blocks groups. Each group contains 1 bitmap block for blocks, 1 bitmap
32 * block for inodes, N blocks for the inode table and data blocks.
34 * The file system contains group descriptors which are located after the
35 * super block. Each descriptor contains the number of the bitmap block and
36 * the free blocks count in the block. The descriptors are loaded in memory
37 * when a file system is mounted (see ext3_read_super).
41 #define in_range(b, first, len) ((b) >= (first) && (b) <= (first) + (len) - 1)
43 struct ext3_group_desc * ext3_get_group_desc(struct super_block * sb,
44 unsigned int block_group,
45 struct buffer_head ** bh)
47 unsigned long group_desc;
49 struct ext3_group_desc * desc;
50 struct ext3_sb_info *sbi = EXT3_SB(sb);
52 if (block_group >= sbi->s_groups_count) {
53 ext3_error (sb, "ext3_get_group_desc",
54 "block_group >= groups_count - "
55 "block_group = %d, groups_count = %lu",
56 block_group, sbi->s_groups_count);
62 group_desc = block_group >> EXT3_DESC_PER_BLOCK_BITS(sb);
63 offset = block_group & (EXT3_DESC_PER_BLOCK(sb) - 1);
64 if (!sbi->s_group_desc[group_desc]) {
65 ext3_error (sb, "ext3_get_group_desc",
66 "Group descriptor not loaded - "
67 "block_group = %d, group_desc = %lu, desc = %lu",
68 block_group, group_desc, offset);
72 desc = (struct ext3_group_desc *) sbi->s_group_desc[group_desc]->b_data;
74 *bh = sbi->s_group_desc[group_desc];
79 * Read the bitmap for a given block_group, reading into the specified
80 * slot in the superblock's bitmap cache.
82 * Return buffer_head on success or NULL in case of failure.
84 static struct buffer_head *
85 read_block_bitmap(struct super_block *sb, unsigned int block_group)
87 struct ext3_group_desc * desc;
88 struct buffer_head * bh = NULL;
90 desc = ext3_get_group_desc (sb, block_group, NULL);
93 bh = sb_bread(sb, le32_to_cpu(desc->bg_block_bitmap));
95 ext3_error (sb, "read_block_bitmap",
96 "Cannot read block bitmap - "
97 "block_group = %d, block_bitmap = %u",
98 block_group, le32_to_cpu(desc->bg_block_bitmap));
103 * The reservation window structure operations
104 * --------------------------------------------
105 * Operations include:
106 * dump, find, add, remove, is_empty, find_next_reservable_window, etc.
108 * We use sorted double linked list for the per-filesystem reservation
109 * window list. (like in vm_region).
111 * Initially, we keep those small operations in the abstract functions,
112 * so later if we need a better searching tree than double linked-list,
113 * we could easily switch to that without changing too much
117 static void __rsv_window_dump(struct rb_root *root, int verbose,
121 struct ext3_reserve_window_node *rsv, *prev;
129 printk("Block Allocation Reservation Windows Map (%s):\n", fn);
131 rsv = list_entry(n, struct ext3_reserve_window_node, rsv_node);
133 printk("reservation window 0x%p "
134 "start: %d, end: %d\n",
135 rsv, rsv->rsv_start, rsv->rsv_end);
136 if (rsv->rsv_start && rsv->rsv_start >= rsv->rsv_end) {
137 printk("Bad reservation %p (start >= end)\n",
141 if (prev && prev->rsv_end >= rsv->rsv_start) {
142 printk("Bad reservation %p (prev->end >= start)\n",
148 printk("Restarting reservation walk in verbose mode\n");
156 printk("Window map complete.\n");
160 #define rsv_window_dump(root, verbose) \
161 __rsv_window_dump((root), (verbose), __FUNCTION__)
163 #define rsv_window_dump(root, verbose) do {} while (0)
167 goal_in_my_reservation(struct ext3_reserve_window *rsv, ext3_grpblk_t grp_goal,
168 unsigned int group, struct super_block * sb)
170 ext3_fsblk_t group_first_block, group_last_block;
172 group_first_block = ext3_group_first_block_no(sb, group);
173 group_last_block = group_first_block + (EXT3_BLOCKS_PER_GROUP(sb) - 1);
175 if ((rsv->_rsv_start > group_last_block) ||
176 (rsv->_rsv_end < group_first_block))
178 if ((grp_goal >= 0) && ((grp_goal + group_first_block < rsv->_rsv_start)
179 || (grp_goal + group_first_block > rsv->_rsv_end)))
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.
189 static struct ext3_reserve_window_node *
190 search_reserve_window(struct rb_root *root, ext3_fsblk_t goal)
192 struct rb_node *n = root->rb_node;
193 struct ext3_reserve_window_node *rsv;
199 rsv = rb_entry(n, struct ext3_reserve_window_node, rsv_node);
201 if (goal < rsv->rsv_start)
203 else if (goal > rsv->rsv_end)
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.
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);
221 void ext3_rsv_window_add(struct super_block *sb,
222 struct ext3_reserve_window_node *rsv)
224 struct rb_root *root = &EXT3_SB(sb)->s_rsv_window_root;
225 struct rb_node *node = &rsv->rsv_node;
226 ext3_fsblk_t start = rsv->rsv_start;
228 struct rb_node ** p = &root->rb_node;
229 struct rb_node * parent = NULL;
230 struct ext3_reserve_window_node *this;
235 this = rb_entry(parent, struct ext3_reserve_window_node, rsv_node);
237 if (start < this->rsv_start)
239 else if (start > this->rsv_end)
245 rb_link_node(node, parent, p);
246 rb_insert_color(node, root);
249 static void rsv_window_remove(struct super_block *sb,
250 struct ext3_reserve_window_node *rsv)
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);
258 static inline int rsv_is_empty(struct ext3_reserve_window *rsv)
260 /* a valid reservation end block could not be 0 */
261 return (rsv->_rsv_end == EXT3_RESERVE_WINDOW_NOT_ALLOCATED);
263 void ext3_init_block_alloc_info(struct inode *inode)
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;
269 block_i = kmalloc(sizeof(*block_i), GFP_NOFS);
271 struct ext3_reserve_window_node *rsv = &block_i->rsv_window_node;
273 rsv->rsv_start = EXT3_RESERVE_WINDOW_NOT_ALLOCATED;
274 rsv->rsv_end = EXT3_RESERVE_WINDOW_NOT_ALLOCATED;
277 * if filesystem is mounted with NORESERVATION, the goal
278 * reservation window size is set to zero to indicate
279 * block reservation is off
281 if (!test_opt(sb, RESERVATION))
282 rsv->rsv_goal_size = 0;
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;
289 ei->i_block_alloc_info = block_i;
292 void ext3_discard_reservation(struct inode *inode)
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;
302 rsv = &block_i->rsv_window_node;
303 if (!rsv_is_empty(&rsv->rsv_window)) {
305 if (!rsv_is_empty(&rsv->rsv_window))
306 rsv_window_remove(inode->i_sb, rsv);
307 spin_unlock(rsv_lock);
311 /* Free given blocks, update quota and i_blocks field */
312 void ext3_free_blocks_sb(handle_t *handle, struct super_block *sb,
313 ext3_fsblk_t block, unsigned long count,
314 unsigned long *pdquot_freed_blocks)
316 struct buffer_head *bitmap_bh = NULL;
317 struct buffer_head *gd_bh;
318 unsigned long block_group;
321 unsigned long overflow;
322 struct ext3_group_desc * desc;
323 struct ext3_super_block * es;
324 struct ext3_sb_info *sbi;
326 ext3_grpblk_t group_freed;
328 *pdquot_freed_blocks = 0;
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 = "E3FSBLK", count = %lu", block, count);
340 ext3_debug ("freeing block(s) %lu-%lu\n", block, block + count - 1);
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);
349 * Check to see if we are freeing blocks across a group
352 if (bit + count > EXT3_BLOCKS_PER_GROUP(sb)) {
353 overflow = bit + count - EXT3_BLOCKS_PER_GROUP(sb);
357 bitmap_bh = read_block_bitmap(sb, block_group);
360 desc = ext3_get_group_desc (sb, block_group, &gd_bh);
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 = "E3FSBLK", count = %lu",
376 * We are about to start releasing blocks in the bitmap,
377 * so we need undo access.
379 /* @@@ check errors */
380 BUFFER_TRACE(bitmap_bh, "getting undo access");
381 err = ext3_journal_get_undo_access(handle, bitmap_bh);
386 * We are about to modify some metadata. Call the journal APIs
387 * to unshare ->b_data if a currently-committing transaction is
390 BUFFER_TRACE(gd_bh, "get_write_access");
391 err = ext3_journal_get_write_access(handle, gd_bh);
395 jbd_lock_bh_state(bitmap_bh);
397 for (i = 0, group_freed = 0; i < count; i++) {
399 * An HJ special. This is expensive...
401 #ifdef CONFIG_JBD_DEBUG
402 jbd_unlock_bh_state(bitmap_bh);
404 struct buffer_head *debug_bh;
405 debug_bh = sb_find_get_block(sb, block + i);
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");
415 jbd_lock_bh_state(bitmap_bh);
417 if (need_resched()) {
418 jbd_unlock_bh_state(bitmap_bh);
420 jbd_lock_bh_state(bitmap_bh);
422 /* @@@ This prevents newly-allocated data from being
423 * freed and then reallocated within the same
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.
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
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);
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.
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 "E3FSBLK,
458 jbd_lock_bh_state(bitmap_bh);
459 BUFFER_TRACE(bitmap_bh, "bit already cleared");
464 jbd_unlock_bh_state(bitmap_bh);
466 spin_lock(sb_bgl_lock(sbi, block_group));
467 desc->bg_free_blocks_count =
468 cpu_to_le16(le16_to_cpu(desc->bg_free_blocks_count) +
470 spin_unlock(sb_bgl_lock(sbi, block_group));
471 percpu_counter_mod(&sbi->s_freeblocks_counter, count);
473 /* We dirtied the bitmap block */
474 BUFFER_TRACE(bitmap_bh, "dirtied bitmap block");
475 err = ext3_journal_dirty_metadata(handle, bitmap_bh);
477 /* And the group descriptor block */
478 BUFFER_TRACE(gd_bh, "dirtied group descriptor block");
479 ret = ext3_journal_dirty_metadata(handle, gd_bh);
481 *pdquot_freed_blocks += group_freed;
483 if (overflow && !err) {
491 ext3_std_error(sb, err);
495 /* Free given blocks, update quota and i_blocks field */
496 void ext3_free_blocks(handle_t *handle, struct inode *inode,
497 ext3_fsblk_t block, unsigned long count)
499 struct super_block * sb;
500 unsigned long dquot_freed_blocks;
504 printk ("ext3_free_blocks: nonexistent device");
507 ext3_free_blocks_sb(handle, sb, block, count, &dquot_freed_blocks);
508 if (dquot_freed_blocks) {
509 DLIMIT_FREE_BLOCK(inode, dquot_freed_blocks);
510 DQUOT_FREE_BLOCK(inode, dquot_freed_blocks);
516 * For ext3 allocations, we must not reuse any blocks which are
517 * allocated in the bitmap buffer's "last committed data" copy. This
518 * prevents deletes from freeing up the page for reuse until we have
519 * committed the delete transaction.
521 * If we didn't do this, then deleting something and reallocating it as
522 * data would allow the old block to be overwritten before the
523 * transaction committed (because we force data to disk before commit).
524 * This would lead to corruption if we crashed between overwriting the
525 * data and committing the delete.
527 * @@@ We may want to make this allocation behaviour conditional on
528 * data-writes at some point, and disable it for metadata allocations or
531 static int ext3_test_allocatable(ext3_grpblk_t nr, struct buffer_head *bh)
534 struct journal_head *jh = bh2jh(bh);
536 if (ext3_test_bit(nr, bh->b_data))
539 jbd_lock_bh_state(bh);
540 if (!jh->b_committed_data)
543 ret = !ext3_test_bit(nr, jh->b_committed_data);
544 jbd_unlock_bh_state(bh);
549 bitmap_search_next_usable_block(ext3_grpblk_t start, struct buffer_head *bh,
550 ext3_grpblk_t maxblocks)
553 struct journal_head *jh = bh2jh(bh);
556 * The bitmap search --- search forward alternately through the actual
557 * bitmap and the last-committed copy until we find a bit free in
560 while (start < maxblocks) {
561 next = ext3_find_next_zero_bit(bh->b_data, maxblocks, start);
562 if (next >= maxblocks)
564 if (ext3_test_allocatable(next, bh))
566 jbd_lock_bh_state(bh);
567 if (jh->b_committed_data)
568 start = ext3_find_next_zero_bit(jh->b_committed_data,
570 jbd_unlock_bh_state(bh);
576 * Find an allocatable block in a bitmap. We honour both the bitmap and
577 * its last-committed copy (if that exists), and perform the "most
578 * appropriate allocation" algorithm of looking for a free block near
579 * the initial goal; then for a free byte somewhere in the bitmap; then
580 * for any free bit in the bitmap.
583 find_next_usable_block(ext3_grpblk_t start, struct buffer_head *bh,
584 ext3_grpblk_t maxblocks)
586 ext3_grpblk_t here, next;
591 * The goal was occupied; search forward for a free
592 * block within the next XX blocks.
594 * end_goal is more or less random, but it has to be
595 * less than EXT3_BLOCKS_PER_GROUP. Aligning up to the
596 * next 64-bit boundary is simple..
598 ext3_grpblk_t end_goal = (start + 63) & ~63;
599 if (end_goal > maxblocks)
600 end_goal = maxblocks;
601 here = ext3_find_next_zero_bit(bh->b_data, end_goal, start);
602 if (here < end_goal && ext3_test_allocatable(here, bh))
604 ext3_debug("Bit not found near goal\n");
611 p = ((char *)bh->b_data) + (here >> 3);
612 r = memscan(p, 0, (maxblocks - here + 7) >> 3);
613 next = (r - ((char *)bh->b_data)) << 3;
615 if (next < maxblocks && next >= start && ext3_test_allocatable(next, bh))
619 * The bitmap search --- search forward alternately through the actual
620 * bitmap and the last-committed copy until we find a bit free in
623 here = bitmap_search_next_usable_block(here, bh, maxblocks);
628 * We think we can allocate this block in this bitmap. Try to set the bit.
629 * If that succeeds then check that nobody has allocated and then freed the
630 * block since we saw that is was not marked in b_committed_data. If it _was_
631 * allocated and freed then clear the bit in the bitmap again and return
635 claim_block(spinlock_t *lock, ext3_grpblk_t block, struct buffer_head *bh)
637 struct journal_head *jh = bh2jh(bh);
640 if (ext3_set_bit_atomic(lock, block, bh->b_data))
642 jbd_lock_bh_state(bh);
643 if (jh->b_committed_data && ext3_test_bit(block,jh->b_committed_data)) {
644 ext3_clear_bit_atomic(lock, block, bh->b_data);
649 jbd_unlock_bh_state(bh);
654 * If we failed to allocate the desired block then we may end up crossing to a
655 * new bitmap. In that case we must release write access to the old one via
656 * ext3_journal_release_buffer(), else we'll run out of credits.
659 ext3_try_to_allocate(struct super_block *sb, handle_t *handle, int group,
660 struct buffer_head *bitmap_bh, ext3_grpblk_t grp_goal,
661 unsigned long *count, struct ext3_reserve_window *my_rsv)
663 ext3_fsblk_t group_first_block;
664 ext3_grpblk_t start, end;
665 unsigned long num = 0;
667 /* we do allocation within the reservation window if we have a window */
669 group_first_block = ext3_group_first_block_no(sb, group);
670 if (my_rsv->_rsv_start >= group_first_block)
671 start = my_rsv->_rsv_start - group_first_block;
673 /* reservation window cross group boundary */
675 end = my_rsv->_rsv_end - group_first_block + 1;
676 if (end > EXT3_BLOCKS_PER_GROUP(sb))
677 /* reservation window crosses group boundary */
678 end = EXT3_BLOCKS_PER_GROUP(sb);
679 if ((start <= grp_goal) && (grp_goal < end))
688 end = EXT3_BLOCKS_PER_GROUP(sb);
691 BUG_ON(start > EXT3_BLOCKS_PER_GROUP(sb));
694 if (grp_goal < 0 || !ext3_test_allocatable(grp_goal, bitmap_bh)) {
695 grp_goal = find_next_usable_block(start, bitmap_bh, end);
701 for (i = 0; i < 7 && grp_goal > start &&
702 ext3_test_allocatable(grp_goal - 1,
710 if (!claim_block(sb_bgl_lock(EXT3_SB(sb), group), grp_goal, bitmap_bh)) {
712 * The block was allocated by another thread, or it was
713 * allocated and then freed by another thread
723 while (num < *count && grp_goal < end
724 && ext3_test_allocatable(grp_goal, bitmap_bh)
725 && claim_block(sb_bgl_lock(EXT3_SB(sb), group), grp_goal, bitmap_bh)) {
730 return grp_goal - num;
737 * find_next_reservable_window():
738 * find a reservable space within the given range.
739 * It does not allocate the reservation window for now:
740 * alloc_new_reservation() will do the work later.
742 * @search_head: the head of the searching list;
743 * This is not necessarily the list head of the whole filesystem
745 * We have both head and start_block to assist the search
746 * for the reservable space. The list starts from head,
747 * but we will shift to the place where start_block is,
748 * then start from there, when looking for a reservable space.
750 * @size: the target new reservation window size
752 * @group_first_block: the first block we consider to start
753 * the real search from
756 * the maximum block number that our goal reservable space
757 * could start from. This is normally the last block in this
758 * group. The search will end when we found the start of next
759 * possible reservable space is out of this boundary.
760 * This could handle the cross boundary reservation window
763 * basically we search from the given range, rather than the whole
764 * reservation double linked list, (start_block, last_block)
765 * to find a free region that is of my size and has not
769 static int find_next_reservable_window(
770 struct ext3_reserve_window_node *search_head,
771 struct ext3_reserve_window_node *my_rsv,
772 struct super_block * sb,
773 ext3_fsblk_t start_block,
774 ext3_fsblk_t last_block)
776 struct rb_node *next;
777 struct ext3_reserve_window_node *rsv, *prev;
779 int size = my_rsv->rsv_goal_size;
781 /* TODO: make the start of the reservation window byte-aligned */
782 /* cur = *start_block & ~7;*/
789 if (cur <= rsv->rsv_end)
790 cur = rsv->rsv_end + 1;
793 * in the case we could not find a reservable space
794 * that is what is expected, during the re-search, we could
795 * remember what's the largest reservable space we could have
796 * and return that one.
798 * For now it will fail if we could not find the reservable
799 * space with expected-size (or more)...
801 if (cur > last_block)
802 return -1; /* fail */
805 next = rb_next(&rsv->rsv_node);
806 rsv = list_entry(next,struct ext3_reserve_window_node,rsv_node);
809 * Reached the last reservation, we can just append to the
815 if (cur + size <= rsv->rsv_start) {
817 * Found a reserveable space big enough. We could
818 * have a reservation across the group boundary here
824 * we come here either :
825 * when we reach the end of the whole list,
826 * and there is empty reservable space after last entry in the list.
827 * append it to the end of the list.
829 * or we found one reservable space in the middle of the list,
830 * return the reservation window that we could append to.
834 if ((prev != my_rsv) && (!rsv_is_empty(&my_rsv->rsv_window)))
835 rsv_window_remove(sb, my_rsv);
838 * Let's book the whole avaliable window for now. We will check the
839 * disk bitmap later and then, if there are free blocks then we adjust
840 * the window size if it's larger than requested.
841 * Otherwise, we will remove this node from the tree next time
842 * call find_next_reservable_window.
844 my_rsv->rsv_start = cur;
845 my_rsv->rsv_end = cur + size - 1;
846 my_rsv->rsv_alloc_hit = 0;
849 ext3_rsv_window_add(sb, my_rsv);
855 * alloc_new_reservation()--allocate a new reservation window
857 * To make a new reservation, we search part of the filesystem
858 * reservation list (the list that inside the group). We try to
859 * allocate a new reservation window near the allocation goal,
860 * or the beginning of the group, if there is no goal.
862 * We first find a reservable space after the goal, then from
863 * there, we check the bitmap for the first free block after
864 * it. If there is no free block until the end of group, then the
865 * whole group is full, we failed. Otherwise, check if the free
866 * block is inside the expected reservable space, if so, we
868 * If the first free block is outside the reservable space, then
869 * start from the first free block, we search for next available
872 * on succeed, a new reservation will be found and inserted into the list
873 * It contains at least one free block, and it does not overlap with other
874 * reservation windows.
876 * failed: we failed to find a reservation window in this group
878 * @rsv: the reservation
880 * @grp_goal: The goal (group-relative). It is where the search for a
881 * free reservable space should start from.
882 * if we have a grp_goal(grp_goal >0 ), then start from there,
883 * no grp_goal(grp_goal = -1), we start from the first block
886 * @sb: the super block
887 * @group: the group we are trying to allocate in
888 * @bitmap_bh: the block group block bitmap
891 static int alloc_new_reservation(struct ext3_reserve_window_node *my_rsv,
892 ext3_grpblk_t grp_goal, struct super_block *sb,
893 unsigned int group, struct buffer_head *bitmap_bh)
895 struct ext3_reserve_window_node *search_head;
896 ext3_fsblk_t group_first_block, group_end_block, start_block;
897 ext3_grpblk_t first_free_block;
898 struct rb_root *fs_rsv_root = &EXT3_SB(sb)->s_rsv_window_root;
901 spinlock_t *rsv_lock = &EXT3_SB(sb)->s_rsv_window_lock;
903 group_first_block = ext3_group_first_block_no(sb, group);
904 group_end_block = group_first_block + (EXT3_BLOCKS_PER_GROUP(sb) - 1);
907 start_block = group_first_block;
909 start_block = grp_goal + group_first_block;
911 size = my_rsv->rsv_goal_size;
913 if (!rsv_is_empty(&my_rsv->rsv_window)) {
915 * if the old reservation is cross group boundary
916 * and if the goal is inside the old reservation window,
917 * we will come here when we just failed to allocate from
918 * the first part of the window. We still have another part
919 * that belongs to the next group. In this case, there is no
920 * point to discard our window and try to allocate a new one
921 * in this group(which will fail). we should
922 * keep the reservation window, just simply move on.
924 * Maybe we could shift the start block of the reservation
925 * window to the first block of next group.
928 if ((my_rsv->rsv_start <= group_end_block) &&
929 (my_rsv->rsv_end > group_end_block) &&
930 (start_block >= my_rsv->rsv_start))
933 if ((my_rsv->rsv_alloc_hit >
934 (my_rsv->rsv_end - my_rsv->rsv_start + 1) / 2)) {
936 * if we previously allocation hit ration is greater than half
937 * we double the size of reservation window next time
938 * otherwise keep the same
941 if (size > EXT3_MAX_RESERVE_BLOCKS)
942 size = EXT3_MAX_RESERVE_BLOCKS;
943 my_rsv->rsv_goal_size= size;
949 * shift the search start to the window near the goal block
951 search_head = search_reserve_window(fs_rsv_root, start_block);
954 * find_next_reservable_window() simply finds a reservable window
955 * inside the given range(start_block, group_end_block).
957 * To make sure the reservation window has a free bit inside it, we
958 * need to check the bitmap after we found a reservable window.
961 ret = find_next_reservable_window(search_head, my_rsv, sb,
962 start_block, group_end_block);
965 if (!rsv_is_empty(&my_rsv->rsv_window))
966 rsv_window_remove(sb, my_rsv);
967 spin_unlock(rsv_lock);
972 * On success, find_next_reservable_window() returns the
973 * reservation window where there is a reservable space after it.
974 * Before we reserve this reservable space, we need
975 * to make sure there is at least a free block inside this region.
977 * searching the first free bit on the block bitmap and copy of
978 * last committed bitmap alternatively, until we found a allocatable
979 * block. Search start from the start block of the reservable space
982 spin_unlock(rsv_lock);
983 first_free_block = bitmap_search_next_usable_block(
984 my_rsv->rsv_start - group_first_block,
985 bitmap_bh, group_end_block - group_first_block + 1);
987 if (first_free_block < 0) {
989 * no free block left on the bitmap, no point
990 * to reserve the space. return failed.
993 if (!rsv_is_empty(&my_rsv->rsv_window))
994 rsv_window_remove(sb, my_rsv);
995 spin_unlock(rsv_lock);
996 return -1; /* failed */
999 start_block = first_free_block + group_first_block;
1001 * check if the first free block is within the
1002 * free space we just reserved
1004 if (start_block >= my_rsv->rsv_start && start_block < my_rsv->rsv_end)
1005 return 0; /* success */
1007 * if the first free bit we found is out of the reservable space
1008 * continue search for next reservable space,
1009 * start from where the free block is,
1010 * we also shift the list head to where we stopped last time
1012 search_head = my_rsv;
1013 spin_lock(rsv_lock);
1017 static void try_to_extend_reservation(struct ext3_reserve_window_node *my_rsv,
1018 struct super_block *sb, int size)
1020 struct ext3_reserve_window_node *next_rsv;
1021 struct rb_node *next;
1022 spinlock_t *rsv_lock = &EXT3_SB(sb)->s_rsv_window_lock;
1024 if (!spin_trylock(rsv_lock))
1027 next = rb_next(&my_rsv->rsv_node);
1030 my_rsv->rsv_end += size;
1032 next_rsv = list_entry(next, struct ext3_reserve_window_node, rsv_node);
1034 if ((next_rsv->rsv_start - my_rsv->rsv_end - 1) >= size)
1035 my_rsv->rsv_end += size;
1037 my_rsv->rsv_end = next_rsv->rsv_start - 1;
1039 spin_unlock(rsv_lock);
1043 * This is the main function used to allocate a new block and its reservation
1046 * Each time when a new block allocation is need, first try to allocate from
1047 * its own reservation. If it does not have a reservation window, instead of
1048 * looking for a free bit on bitmap first, then look up the reservation list to
1049 * see if it is inside somebody else's reservation window, we try to allocate a
1050 * reservation window for it starting from the goal first. Then do the block
1051 * allocation within the reservation window.
1053 * This will avoid keeping on searching the reservation list again and
1054 * again when somebody is looking for a free block (without
1055 * reservation), and there are lots of free blocks, but they are all
1058 * We use a sorted double linked list for the per-filesystem reservation list.
1059 * The insert, remove and find a free space(non-reserved) operations for the
1060 * sorted double linked list should be fast.
1063 static ext3_grpblk_t
1064 ext3_try_to_allocate_with_rsv(struct super_block *sb, handle_t *handle,
1065 unsigned int group, struct buffer_head *bitmap_bh,
1066 ext3_grpblk_t grp_goal,
1067 struct ext3_reserve_window_node * my_rsv,
1068 unsigned long *count, int *errp)
1070 ext3_fsblk_t group_first_block, group_last_block;
1071 ext3_grpblk_t ret = 0;
1073 unsigned long num = *count;
1078 * Make sure we use undo access for the bitmap, because it is critical
1079 * that we do the frozen_data COW on bitmap buffers in all cases even
1080 * if the buffer is in BJ_Forget state in the committing transaction.
1082 BUFFER_TRACE(bitmap_bh, "get undo access for new block");
1083 fatal = ext3_journal_get_undo_access(handle, bitmap_bh);
1090 * we don't deal with reservation when
1091 * filesystem is mounted without reservation
1092 * or the file is not a regular file
1093 * or last attempt to allocate a block with reservation turned on failed
1095 if (my_rsv == NULL ) {
1096 ret = ext3_try_to_allocate(sb, handle, group, bitmap_bh,
1097 grp_goal, count, NULL);
1101 * grp_goal is a group relative block number (if there is a goal)
1102 * 0 < grp_goal < EXT3_BLOCKS_PER_GROUP(sb)
1103 * first block is a filesystem wide block number
1104 * first block is the block number of the first block in this group
1106 group_first_block = ext3_group_first_block_no(sb, group);
1107 group_last_block = group_first_block + (EXT3_BLOCKS_PER_GROUP(sb) - 1);
1110 * Basically we will allocate a new block from inode's reservation
1113 * We need to allocate a new reservation window, if:
1114 * a) inode does not have a reservation window; or
1115 * b) last attempt to allocate a block from existing reservation
1117 * c) we come here with a goal and with a reservation window
1119 * We do not need to allocate a new reservation window if we come here
1120 * at the beginning with a goal and the goal is inside the window, or
1121 * we don't have a goal but already have a reservation window.
1122 * then we could go to allocate from the reservation window directly.
1125 if (rsv_is_empty(&my_rsv->rsv_window) || (ret < 0) ||
1126 !goal_in_my_reservation(&my_rsv->rsv_window, grp_goal, group, sb)) {
1127 if (my_rsv->rsv_goal_size < *count)
1128 my_rsv->rsv_goal_size = *count;
1129 ret = alloc_new_reservation(my_rsv, grp_goal, sb,
1134 if (!goal_in_my_reservation(&my_rsv->rsv_window, grp_goal, group, sb))
1136 } else if (grp_goal > 0 && (my_rsv->rsv_end-grp_goal+1) < *count)
1137 try_to_extend_reservation(my_rsv, sb,
1138 *count-my_rsv->rsv_end + grp_goal - 1);
1140 if ((my_rsv->rsv_start > group_last_block) ||
1141 (my_rsv->rsv_end < group_first_block))
1143 ret = ext3_try_to_allocate(sb, handle, group, bitmap_bh, grp_goal,
1144 &num, &my_rsv->rsv_window);
1146 my_rsv->rsv_alloc_hit += num;
1148 break; /* succeed */
1154 BUFFER_TRACE(bitmap_bh, "journal_dirty_metadata for "
1156 fatal = ext3_journal_dirty_metadata(handle, bitmap_bh);
1164 BUFFER_TRACE(bitmap_bh, "journal_release_buffer");
1165 ext3_journal_release_buffer(handle, bitmap_bh);
1169 static int ext3_has_free_blocks(struct super_block *sb)
1171 struct ext3_sb_info *sbi = EXT3_SB(sb);
1172 ext3_fsblk_t free_blocks, root_blocks;
1175 free_blocks = percpu_counter_read_positive(&sbi->s_freeblocks_counter);
1176 root_blocks = le32_to_cpu(sbi->s_es->s_r_blocks_count);
1178 vxdprintk(VXD_CBIT(dlim, 3),
1179 "ext3_has_free_blocks(%p): free=%lu, root=%lu",
1180 sb, free_blocks, root_blocks);
1182 DLIMIT_ADJUST_BLOCK(sb, vx_current_xid(), &free_blocks, &root_blocks);
1184 cond = (free_blocks < root_blocks + 1 &&
1185 !capable(CAP_SYS_RESOURCE) &&
1186 sbi->s_resuid != current->fsuid &&
1187 (sbi->s_resgid == 0 || !in_group_p (sbi->s_resgid)));
1189 vxdprintk(VXD_CBIT(dlim, 3),
1190 "ext3_has_free_blocks(%p): %lu<%lu+1, %c, %u!=%u r=%d",
1191 sb, free_blocks, root_blocks,
1192 !capable(CAP_SYS_RESOURCE)?'1':'0',
1193 sbi->s_resuid, current->fsuid, cond?0:1);
1195 return (cond ? 0 : 1);
1199 * ext3_should_retry_alloc() is called when ENOSPC is returned, and if
1200 * it is profitable to retry the operation, this function will wait
1201 * for the current or commiting transaction to complete, and then
1204 int ext3_should_retry_alloc(struct super_block *sb, int *retries)
1206 if (!ext3_has_free_blocks(sb) || (*retries)++ > 3)
1209 jbd_debug(1, "%s: retrying operation after ENOSPC\n", sb->s_id);
1211 return journal_force_commit_nested(EXT3_SB(sb)->s_journal);
1215 * ext3_new_block uses a goal block to assist allocation. If the goal is
1216 * free, or there is a free block within 32 blocks of the goal, that block
1217 * is allocated. Otherwise a forward search is made for a free block; within
1218 * each block group the search first looks for an entire free byte in the block
1219 * bitmap, and then for any free bit if that fails.
1220 * This function also updates quota and i_blocks field.
1222 ext3_fsblk_t ext3_new_blocks(handle_t *handle, struct inode *inode,
1223 ext3_fsblk_t goal, unsigned long *count, int *errp)
1225 struct buffer_head *bitmap_bh = NULL;
1226 struct buffer_head *gdp_bh;
1229 ext3_grpblk_t grp_target_blk; /* blockgroup relative goal block */
1230 ext3_grpblk_t grp_alloc_blk; /* blockgroup-relative allocated block*/
1231 ext3_fsblk_t ret_block; /* filesyetem-wide allocated block */
1232 int bgi; /* blockgroup iteration index */
1234 int performed_allocation = 0;
1235 ext3_grpblk_t free_blocks; /* number of free blocks in a group */
1236 struct super_block *sb;
1237 struct ext3_group_desc *gdp;
1238 struct ext3_super_block *es;
1239 struct ext3_sb_info *sbi;
1240 struct ext3_reserve_window_node *my_rsv = NULL;
1241 struct ext3_block_alloc_info *block_i;
1242 unsigned short windowsz = 0;
1244 static int goal_hits, goal_attempts;
1246 unsigned long ngroups;
1247 unsigned long num = *count;
1252 printk("ext3_new_block: nonexistent device");
1257 * Check quota for allocation of this block.
1259 if (DQUOT_ALLOC_BLOCK(inode, num)) {
1263 if (DLIMIT_ALLOC_BLOCK(inode, 1))
1267 es = EXT3_SB(sb)->s_es;
1268 ext3_debug("goal=%lu.\n", goal);
1270 * Allocate a block from reservation only when
1271 * filesystem is mounted with reservation(default,-o reservation), and
1272 * it's a regular file, and
1273 * the desired window size is greater than 0 (One could use ioctl
1274 * command EXT3_IOC_SETRSVSZ to set the window size to 0 to turn off
1275 * reservation on that particular file)
1277 block_i = EXT3_I(inode)->i_block_alloc_info;
1278 if (block_i && ((windowsz = block_i->rsv_window_node.rsv_goal_size) > 0))
1279 my_rsv = &block_i->rsv_window_node;
1281 if (!ext3_has_free_blocks(sb)) {
1287 * First, test whether the goal block is free.
1289 if (goal < le32_to_cpu(es->s_first_data_block) ||
1290 goal >= le32_to_cpu(es->s_blocks_count))
1291 goal = le32_to_cpu(es->s_first_data_block);
1292 group_no = (goal - le32_to_cpu(es->s_first_data_block)) /
1293 EXT3_BLOCKS_PER_GROUP(sb);
1294 goal_group = group_no;
1296 gdp = ext3_get_group_desc(sb, group_no, &gdp_bh);
1300 free_blocks = le16_to_cpu(gdp->bg_free_blocks_count);
1302 * if there is not enough free blocks to make a new resevation
1303 * turn off reservation for this allocation
1305 if (my_rsv && (free_blocks < windowsz)
1306 && (rsv_is_empty(&my_rsv->rsv_window)))
1309 if (free_blocks > 0) {
1310 grp_target_blk = ((goal - le32_to_cpu(es->s_first_data_block)) %
1311 EXT3_BLOCKS_PER_GROUP(sb));
1312 bitmap_bh = read_block_bitmap(sb, group_no);
1315 grp_alloc_blk = ext3_try_to_allocate_with_rsv(sb, handle,
1316 group_no, bitmap_bh, grp_target_blk,
1317 my_rsv, &num, &fatal);
1320 if (grp_alloc_blk >= 0)
1324 ngroups = EXT3_SB(sb)->s_groups_count;
1328 * Now search the rest of the groups. We assume that
1329 * i and gdp correctly point to the last group visited.
1331 for (bgi = 0; bgi < ngroups; bgi++) {
1333 if (group_no >= ngroups)
1335 gdp = ext3_get_group_desc(sb, group_no, &gdp_bh);
1340 free_blocks = le16_to_cpu(gdp->bg_free_blocks_count);
1342 * skip this group if the number of
1343 * free blocks is less than half of the reservation
1346 if (free_blocks <= (windowsz/2))
1350 bitmap_bh = read_block_bitmap(sb, group_no);
1354 * try to allocate block(s) from this group, without a goal(-1).
1356 grp_alloc_blk = ext3_try_to_allocate_with_rsv(sb, handle,
1357 group_no, bitmap_bh, -1, my_rsv,
1361 if (grp_alloc_blk >= 0)
1365 * We may end up a bogus ealier ENOSPC error due to
1366 * filesystem is "full" of reservations, but
1367 * there maybe indeed free blocks avaliable on disk
1368 * In this case, we just forget about the reservations
1369 * just do block allocation as without reservations.
1373 group_no = goal_group;
1376 /* No space left on the device */
1382 ext3_debug("using block group %d(%d)\n",
1383 group_no, gdp->bg_free_blocks_count);
1385 BUFFER_TRACE(gdp_bh, "get_write_access");
1386 fatal = ext3_journal_get_write_access(handle, gdp_bh);
1390 ret_block = grp_alloc_blk + ext3_group_first_block_no(sb, group_no);
1392 if (in_range(le32_to_cpu(gdp->bg_block_bitmap), ret_block, num) ||
1393 in_range(le32_to_cpu(gdp->bg_inode_bitmap), ret_block, num) ||
1394 in_range(ret_block, le32_to_cpu(gdp->bg_inode_table),
1395 EXT3_SB(sb)->s_itb_per_group) ||
1396 in_range(ret_block + num - 1, le32_to_cpu(gdp->bg_inode_table),
1397 EXT3_SB(sb)->s_itb_per_group))
1398 ext3_error(sb, "ext3_new_block",
1399 "Allocating block in system zone - "
1400 "blocks from "E3FSBLK", length %lu",
1403 performed_allocation = 1;
1405 #ifdef CONFIG_JBD_DEBUG
1407 struct buffer_head *debug_bh;
1409 /* Record bitmap buffer state in the newly allocated block */
1410 debug_bh = sb_find_get_block(sb, ret_block);
1412 BUFFER_TRACE(debug_bh, "state when allocated");
1413 BUFFER_TRACE2(debug_bh, bitmap_bh, "bitmap state");
1417 jbd_lock_bh_state(bitmap_bh);
1418 spin_lock(sb_bgl_lock(sbi, group_no));
1419 if (buffer_jbd(bitmap_bh) && bh2jh(bitmap_bh)->b_committed_data) {
1422 for (i = 0; i < num; i++) {
1423 if (ext3_test_bit(grp_alloc_blk+i,
1424 bh2jh(bitmap_bh)->b_committed_data)) {
1425 printk("%s: block was unexpectedly set in "
1426 "b_committed_data\n", __FUNCTION__);
1430 ext3_debug("found bit %d\n", grp_alloc_blk);
1431 spin_unlock(sb_bgl_lock(sbi, group_no));
1432 jbd_unlock_bh_state(bitmap_bh);
1435 if (ret_block + num - 1 >= le32_to_cpu(es->s_blocks_count)) {
1436 ext3_error(sb, "ext3_new_block",
1437 "block("E3FSBLK") >= blocks count(%d) - "
1438 "block_group = %d, es == %p ", ret_block,
1439 le32_to_cpu(es->s_blocks_count), group_no, es);
1444 * It is up to the caller to add the new buffer to a journal
1445 * list of some description. We don't know in advance whether
1446 * the caller wants to use it as metadata or data.
1448 ext3_debug("allocating block %lu. Goal hits %d of %d.\n",
1449 ret_block, goal_hits, goal_attempts);
1451 spin_lock(sb_bgl_lock(sbi, group_no));
1452 gdp->bg_free_blocks_count =
1453 cpu_to_le16(le16_to_cpu(gdp->bg_free_blocks_count) - num);
1454 spin_unlock(sb_bgl_lock(sbi, group_no));
1455 percpu_counter_mod(&sbi->s_freeblocks_counter, -num);
1457 BUFFER_TRACE(gdp_bh, "journal_dirty_metadata for group descriptor");
1458 err = ext3_journal_dirty_metadata(handle, gdp_bh);
1468 DQUOT_FREE_BLOCK(inode, *count-num);
1475 if (!performed_allocation)
1476 DLIMIT_FREE_BLOCK(inode, 1);
1480 ext3_std_error(sb, fatal);
1483 * Undo the block allocation
1485 if (!performed_allocation)
1486 DQUOT_FREE_BLOCK(inode, *count);
1491 ext3_fsblk_t ext3_new_block(handle_t *handle, struct inode *inode,
1492 ext3_fsblk_t goal, int *errp)
1494 unsigned long count = 1;
1496 return ext3_new_blocks(handle, inode, goal, &count, errp);
1499 ext3_fsblk_t ext3_count_free_blocks(struct super_block *sb)
1501 ext3_fsblk_t desc_count;
1502 struct ext3_group_desc *gdp;
1504 unsigned long ngroups = EXT3_SB(sb)->s_groups_count;
1506 struct ext3_super_block *es;
1507 ext3_fsblk_t bitmap_count;
1509 struct buffer_head *bitmap_bh = NULL;
1511 es = EXT3_SB(sb)->s_es;
1517 for (i = 0; i < ngroups; i++) {
1518 gdp = ext3_get_group_desc(sb, i, NULL);
1521 desc_count += le16_to_cpu(gdp->bg_free_blocks_count);
1523 bitmap_bh = read_block_bitmap(sb, i);
1524 if (bitmap_bh == NULL)
1527 x = ext3_count_free(bitmap_bh, sb->s_blocksize);
1528 printk("group %d: stored = %d, counted = %lu\n",
1529 i, le16_to_cpu(gdp->bg_free_blocks_count), x);
1533 printk("ext3_count_free_blocks: stored = "E3FSBLK
1534 ", computed = "E3FSBLK", "E3FSBLK"\n",
1535 le32_to_cpu(es->s_free_blocks_count),
1536 desc_count, bitmap_count);
1537 return bitmap_count;
1541 for (i = 0; i < ngroups; i++) {
1542 gdp = ext3_get_group_desc(sb, i, NULL);
1545 desc_count += le16_to_cpu(gdp->bg_free_blocks_count);
1553 block_in_use(ext3_fsblk_t block, struct super_block *sb, unsigned char *map)
1555 return ext3_test_bit ((block -
1556 le32_to_cpu(EXT3_SB(sb)->s_es->s_first_data_block)) %
1557 EXT3_BLOCKS_PER_GROUP(sb), map);
1560 static inline int test_root(int a, int b)
1569 static int ext3_group_sparse(int group)
1575 return (test_root(group, 7) || test_root(group, 5) ||
1576 test_root(group, 3));
1580 * ext3_bg_has_super - number of blocks used by the superblock in group
1581 * @sb: superblock for filesystem
1582 * @group: group number to check
1584 * Return the number of blocks used by the superblock (primary or backup)
1585 * in this group. Currently this will be only 0 or 1.
1587 int ext3_bg_has_super(struct super_block *sb, int group)
1589 if (EXT3_HAS_RO_COMPAT_FEATURE(sb,
1590 EXT3_FEATURE_RO_COMPAT_SPARSE_SUPER) &&
1591 !ext3_group_sparse(group))
1596 static unsigned long ext3_bg_num_gdb_meta(struct super_block *sb, int group)
1598 unsigned long metagroup = group / EXT3_DESC_PER_BLOCK(sb);
1599 unsigned long first = metagroup * EXT3_DESC_PER_BLOCK(sb);
1600 unsigned long last = first + EXT3_DESC_PER_BLOCK(sb) - 1;
1602 if (group == first || group == first + 1 || group == last)
1607 static unsigned long ext3_bg_num_gdb_nometa(struct super_block *sb, int group)
1609 if (EXT3_HAS_RO_COMPAT_FEATURE(sb,
1610 EXT3_FEATURE_RO_COMPAT_SPARSE_SUPER) &&
1611 !ext3_group_sparse(group))
1613 return EXT3_SB(sb)->s_gdb_count;
1617 * ext3_bg_num_gdb - number of blocks used by the group table in group
1618 * @sb: superblock for filesystem
1619 * @group: group number to check
1621 * Return the number of blocks used by the group descriptor table
1622 * (primary or backup) in this group. In the future there may be a
1623 * different number of descriptor blocks in each group.
1625 unsigned long ext3_bg_num_gdb(struct super_block *sb, int group)
1627 unsigned long first_meta_bg =
1628 le32_to_cpu(EXT3_SB(sb)->s_es->s_first_meta_bg);
1629 unsigned long metagroup = group / EXT3_DESC_PER_BLOCK(sb);
1631 if (!EXT3_HAS_INCOMPAT_FEATURE(sb,EXT3_FEATURE_INCOMPAT_META_BG) ||
1632 metagroup < first_meta_bg)
1633 return ext3_bg_num_gdb_nometa(sb,group);
1635 return ext3_bg_num_gdb_meta(sb,group);