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>
24 * balloc.c contains the blocks allocation and deallocation routines
28 * The free blocks are managed by bitmaps. A file system contains several
29 * blocks groups. Each group contains 1 bitmap block for blocks, 1 bitmap
30 * block for inodes, N blocks for the inode table and data blocks.
32 * The file system contains group descriptors which are located after the
33 * super block. Each descriptor contains the number of the bitmap block and
34 * the free blocks count in the block. The descriptors are loaded in memory
35 * when a file system is mounted (see ext3_read_super).
39 #define in_range(b, first, len) ((b) >= (first) && (b) <= (first) + (len) - 1)
41 struct ext3_group_desc
* ext3_get_group_desc(struct super_block
* sb
,
42 unsigned int block_group
,
43 struct buffer_head
** bh
)
45 unsigned long group_desc
;
47 struct ext3_group_desc
* desc
;
48 struct ext3_sb_info
*sbi
= EXT3_SB(sb
);
50 if (block_group
>= sbi
->s_groups_count
) {
51 ext3_error (sb
, "ext3_get_group_desc",
52 "block_group >= groups_count - "
53 "block_group = %d, groups_count = %lu",
54 block_group
, sbi
->s_groups_count
);
60 group_desc
= block_group
>> EXT3_DESC_PER_BLOCK_BITS(sb
);
61 offset
= block_group
& (EXT3_DESC_PER_BLOCK(sb
) - 1);
62 if (!sbi
->s_group_desc
[group_desc
]) {
63 ext3_error (sb
, "ext3_get_group_desc",
64 "Group descriptor not loaded - "
65 "block_group = %d, group_desc = %lu, desc = %lu",
66 block_group
, group_desc
, offset
);
70 desc
= (struct ext3_group_desc
*) sbi
->s_group_desc
[group_desc
]->b_data
;
72 *bh
= sbi
->s_group_desc
[group_desc
];
77 * Read the bitmap for a given block_group, reading into the specified
78 * slot in the superblock's bitmap cache.
80 * Return buffer_head on success or NULL in case of failure.
82 static struct buffer_head
*
83 read_block_bitmap(struct super_block
*sb
, unsigned int block_group
)
85 struct ext3_group_desc
* desc
;
86 struct buffer_head
* bh
= NULL
;
88 desc
= ext3_get_group_desc (sb
, block_group
, NULL
);
91 bh
= sb_bread(sb
, le32_to_cpu(desc
->bg_block_bitmap
));
93 ext3_error (sb
, "read_block_bitmap",
94 "Cannot read block bitmap - "
95 "block_group = %d, block_bitmap = %u",
96 block_group
, le32_to_cpu(desc
->bg_block_bitmap
));
101 * The reservation window structure operations
102 * --------------------------------------------
103 * Operations include:
104 * dump, find, add, remove, is_empty, find_next_reservable_window, etc.
106 * We use sorted double linked list for the per-filesystem reservation
107 * window list. (like in vm_region).
109 * Initially, we keep those small operations in the abstract functions,
110 * so later if we need a better searching tree than double linked-list,
111 * we could easily switch to that without changing too much
115 static void __rsv_window_dump(struct rb_root
*root
, int verbose
,
119 struct ext3_reserve_window_node
*rsv
, *prev
;
127 printk("Block Allocation Reservation Windows Map (%s):\n", fn
);
129 rsv
= list_entry(n
, struct ext3_reserve_window_node
, rsv_node
);
131 printk("reservation window 0x%p "
132 "start: %d, end: %d\n",
133 rsv
, rsv
->rsv_start
, rsv
->rsv_end
);
134 if (rsv
->rsv_start
&& rsv
->rsv_start
>= rsv
->rsv_end
) {
135 printk("Bad reservation %p (start >= end)\n",
139 if (prev
&& prev
->rsv_end
>= rsv
->rsv_start
) {
140 printk("Bad reservation %p (prev->end >= start)\n",
146 printk("Restarting reservation walk in verbose mode\n");
154 printk("Window map complete.\n");
158 #define rsv_window_dump(root, verbose) \
159 __rsv_window_dump((root), (verbose), __FUNCTION__)
161 #define rsv_window_dump(root, verbose) do {} while (0)
165 goal_in_my_reservation(struct ext3_reserve_window
*rsv
, ext3_grpblk_t grp_goal
,
166 unsigned int group
, struct super_block
* sb
)
168 ext3_fsblk_t group_first_block
, group_last_block
;
170 group_first_block
= ext3_group_first_block_no(sb
, group
);
171 group_last_block
= group_first_block
+ EXT3_BLOCKS_PER_GROUP(sb
) - 1;
173 if ((rsv
->_rsv_start
> group_last_block
) ||
174 (rsv
->_rsv_end
< group_first_block
))
176 if ((grp_goal
>= 0) && ((grp_goal
+ group_first_block
< rsv
->_rsv_start
)
177 || (grp_goal
+ group_first_block
> rsv
->_rsv_end
)))
183 * Find the reserved window which includes the goal, or the previous one
184 * if the goal is not in any window.
185 * Returns NULL if there are no windows or if all windows start after the goal.
187 static struct ext3_reserve_window_node
*
188 search_reserve_window(struct rb_root
*root
, ext3_fsblk_t goal
)
190 struct rb_node
*n
= root
->rb_node
;
191 struct ext3_reserve_window_node
*rsv
;
197 rsv
= rb_entry(n
, struct ext3_reserve_window_node
, rsv_node
);
199 if (goal
< rsv
->rsv_start
)
201 else if (goal
> rsv
->rsv_end
)
207 * We've fallen off the end of the tree: the goal wasn't inside
208 * any particular node. OK, the previous node must be to one
209 * side of the interval containing the goal. If it's the RHS,
210 * we need to back up one.
212 if (rsv
->rsv_start
> goal
) {
213 n
= rb_prev(&rsv
->rsv_node
);
214 rsv
= rb_entry(n
, struct ext3_reserve_window_node
, rsv_node
);
219 void ext3_rsv_window_add(struct super_block
*sb
,
220 struct ext3_reserve_window_node
*rsv
)
222 struct rb_root
*root
= &EXT3_SB(sb
)->s_rsv_window_root
;
223 struct rb_node
*node
= &rsv
->rsv_node
;
224 ext3_fsblk_t start
= rsv
->rsv_start
;
226 struct rb_node
** p
= &root
->rb_node
;
227 struct rb_node
* parent
= NULL
;
228 struct ext3_reserve_window_node
*this;
233 this = rb_entry(parent
, struct ext3_reserve_window_node
, rsv_node
);
235 if (start
< this->rsv_start
)
237 else if (start
> this->rsv_end
)
243 rb_link_node(node
, parent
, p
);
244 rb_insert_color(node
, root
);
247 static void rsv_window_remove(struct super_block
*sb
,
248 struct ext3_reserve_window_node
*rsv
)
250 rsv
->rsv_start
= EXT3_RESERVE_WINDOW_NOT_ALLOCATED
;
251 rsv
->rsv_end
= EXT3_RESERVE_WINDOW_NOT_ALLOCATED
;
252 rsv
->rsv_alloc_hit
= 0;
253 rb_erase(&rsv
->rsv_node
, &EXT3_SB(sb
)->s_rsv_window_root
);
256 static inline int rsv_is_empty(struct ext3_reserve_window
*rsv
)
258 /* a valid reservation end block could not be 0 */
259 return (rsv
->_rsv_end
== EXT3_RESERVE_WINDOW_NOT_ALLOCATED
);
261 void ext3_init_block_alloc_info(struct inode
*inode
)
263 struct ext3_inode_info
*ei
= EXT3_I(inode
);
264 struct ext3_block_alloc_info
*block_i
= ei
->i_block_alloc_info
;
265 struct super_block
*sb
= inode
->i_sb
;
267 block_i
= kmalloc(sizeof(*block_i
), GFP_NOFS
);
269 struct ext3_reserve_window_node
*rsv
= &block_i
->rsv_window_node
;
271 rsv
->rsv_start
= EXT3_RESERVE_WINDOW_NOT_ALLOCATED
;
272 rsv
->rsv_end
= EXT3_RESERVE_WINDOW_NOT_ALLOCATED
;
275 * if filesystem is mounted with NORESERVATION, the goal
276 * reservation window size is set to zero to indicate
277 * block reservation is off
279 if (!test_opt(sb
, RESERVATION
))
280 rsv
->rsv_goal_size
= 0;
282 rsv
->rsv_goal_size
= EXT3_DEFAULT_RESERVE_BLOCKS
;
283 rsv
->rsv_alloc_hit
= 0;
284 block_i
->last_alloc_logical_block
= 0;
285 block_i
->last_alloc_physical_block
= 0;
287 ei
->i_block_alloc_info
= block_i
;
290 void ext3_discard_reservation(struct inode
*inode
)
292 struct ext3_inode_info
*ei
= EXT3_I(inode
);
293 struct ext3_block_alloc_info
*block_i
= ei
->i_block_alloc_info
;
294 struct ext3_reserve_window_node
*rsv
;
295 spinlock_t
*rsv_lock
= &EXT3_SB(inode
->i_sb
)->s_rsv_window_lock
;
300 rsv
= &block_i
->rsv_window_node
;
301 if (!rsv_is_empty(&rsv
->rsv_window
)) {
303 if (!rsv_is_empty(&rsv
->rsv_window
))
304 rsv_window_remove(inode
->i_sb
, rsv
);
305 spin_unlock(rsv_lock
);
309 /* Free given blocks, update quota and i_blocks field */
310 void ext3_free_blocks_sb(handle_t
*handle
, struct super_block
*sb
,
311 ext3_fsblk_t block
, unsigned long count
,
312 unsigned long *pdquot_freed_blocks
)
314 struct buffer_head
*bitmap_bh
= NULL
;
315 struct buffer_head
*gd_bh
;
316 unsigned long block_group
;
319 unsigned long overflow
;
320 struct ext3_group_desc
* desc
;
321 struct ext3_super_block
* es
;
322 struct ext3_sb_info
*sbi
;
324 ext3_grpblk_t group_freed
;
326 *pdquot_freed_blocks
= 0;
329 if (block
< le32_to_cpu(es
->s_first_data_block
) ||
330 block
+ count
< block
||
331 block
+ count
> le32_to_cpu(es
->s_blocks_count
)) {
332 ext3_error (sb
, "ext3_free_blocks",
333 "Freeing blocks not in datazone - "
334 "block = "E3FSBLK
", count = %lu", block
, count
);
338 ext3_debug ("freeing block(s) %lu-%lu\n", block
, block
+ count
- 1);
342 block_group
= (block
- le32_to_cpu(es
->s_first_data_block
)) /
343 EXT3_BLOCKS_PER_GROUP(sb
);
344 bit
= (block
- le32_to_cpu(es
->s_first_data_block
)) %
345 EXT3_BLOCKS_PER_GROUP(sb
);
347 * Check to see if we are freeing blocks across a group
350 if (bit
+ count
> EXT3_BLOCKS_PER_GROUP(sb
)) {
351 overflow
= bit
+ count
- EXT3_BLOCKS_PER_GROUP(sb
);
355 bitmap_bh
= read_block_bitmap(sb
, block_group
);
358 desc
= ext3_get_group_desc (sb
, block_group
, &gd_bh
);
362 if (in_range (le32_to_cpu(desc
->bg_block_bitmap
), block
, count
) ||
363 in_range (le32_to_cpu(desc
->bg_inode_bitmap
), block
, count
) ||
364 in_range (block
, le32_to_cpu(desc
->bg_inode_table
),
365 sbi
->s_itb_per_group
) ||
366 in_range (block
+ count
- 1, le32_to_cpu(desc
->bg_inode_table
),
367 sbi
->s_itb_per_group
))
368 ext3_error (sb
, "ext3_free_blocks",
369 "Freeing blocks in system zones - "
370 "Block = "E3FSBLK
", count = %lu",
374 * We are about to start releasing blocks in the bitmap,
375 * so we need undo access.
377 /* @@@ check errors */
378 BUFFER_TRACE(bitmap_bh
, "getting undo access");
379 err
= ext3_journal_get_undo_access(handle
, bitmap_bh
);
384 * We are about to modify some metadata. Call the journal APIs
385 * to unshare ->b_data if a currently-committing transaction is
388 BUFFER_TRACE(gd_bh
, "get_write_access");
389 err
= ext3_journal_get_write_access(handle
, gd_bh
);
393 jbd_lock_bh_state(bitmap_bh
);
395 for (i
= 0, group_freed
= 0; i
< count
; i
++) {
397 * An HJ special. This is expensive...
399 #ifdef CONFIG_JBD_DEBUG
400 jbd_unlock_bh_state(bitmap_bh
);
402 struct buffer_head
*debug_bh
;
403 debug_bh
= sb_find_get_block(sb
, block
+ i
);
405 BUFFER_TRACE(debug_bh
, "Deleted!");
406 if (!bh2jh(bitmap_bh
)->b_committed_data
)
407 BUFFER_TRACE(debug_bh
,
408 "No commited data in bitmap");
409 BUFFER_TRACE2(debug_bh
, bitmap_bh
, "bitmap");
413 jbd_lock_bh_state(bitmap_bh
);
415 if (need_resched()) {
416 jbd_unlock_bh_state(bitmap_bh
);
418 jbd_lock_bh_state(bitmap_bh
);
420 /* @@@ This prevents newly-allocated data from being
421 * freed and then reallocated within the same
424 * Ideally we would want to allow that to happen, but to
425 * do so requires making journal_forget() capable of
426 * revoking the queued write of a data block, which
427 * implies blocking on the journal lock. *forget()
428 * cannot block due to truncate races.
430 * Eventually we can fix this by making journal_forget()
431 * return a status indicating whether or not it was able
432 * to revoke the buffer. On successful revoke, it is
433 * safe not to set the allocation bit in the committed
434 * bitmap, because we know that there is no outstanding
435 * activity on the buffer any more and so it is safe to
438 BUFFER_TRACE(bitmap_bh
, "set in b_committed_data");
439 J_ASSERT_BH(bitmap_bh
,
440 bh2jh(bitmap_bh
)->b_committed_data
!= NULL
);
441 ext3_set_bit_atomic(sb_bgl_lock(sbi
, block_group
), bit
+ i
,
442 bh2jh(bitmap_bh
)->b_committed_data
);
445 * We clear the bit in the bitmap after setting the committed
446 * data bit, because this is the reverse order to that which
447 * the allocator uses.
449 BUFFER_TRACE(bitmap_bh
, "clear bit");
450 if (!ext3_clear_bit_atomic(sb_bgl_lock(sbi
, block_group
),
451 bit
+ i
, bitmap_bh
->b_data
)) {
452 jbd_unlock_bh_state(bitmap_bh
);
453 ext3_error(sb
, __FUNCTION__
,
454 "bit already cleared for block "E3FSBLK
,
456 jbd_lock_bh_state(bitmap_bh
);
457 BUFFER_TRACE(bitmap_bh
, "bit already cleared");
462 jbd_unlock_bh_state(bitmap_bh
);
464 spin_lock(sb_bgl_lock(sbi
, block_group
));
465 desc
->bg_free_blocks_count
=
466 cpu_to_le16(le16_to_cpu(desc
->bg_free_blocks_count
) +
468 spin_unlock(sb_bgl_lock(sbi
, block_group
));
469 percpu_counter_mod(&sbi
->s_freeblocks_counter
, count
);
471 /* We dirtied the bitmap block */
472 BUFFER_TRACE(bitmap_bh
, "dirtied bitmap block");
473 err
= ext3_journal_dirty_metadata(handle
, bitmap_bh
);
475 /* And the group descriptor block */
476 BUFFER_TRACE(gd_bh
, "dirtied group descriptor block");
477 ret
= ext3_journal_dirty_metadata(handle
, gd_bh
);
479 *pdquot_freed_blocks
+= group_freed
;
481 if (overflow
&& !err
) {
489 ext3_std_error(sb
, err
);
493 /* Free given blocks, update quota and i_blocks field */
494 void ext3_free_blocks(handle_t
*handle
, struct inode
*inode
,
495 ext3_fsblk_t block
, unsigned long count
)
497 struct super_block
* sb
;
498 unsigned long dquot_freed_blocks
;
502 printk ("ext3_free_blocks: nonexistent device");
505 ext3_free_blocks_sb(handle
, sb
, block
, count
, &dquot_freed_blocks
);
506 if (dquot_freed_blocks
)
507 DQUOT_FREE_BLOCK(inode
, dquot_freed_blocks
);
512 * For ext3 allocations, we must not reuse any blocks which are
513 * allocated in the bitmap buffer's "last committed data" copy. This
514 * prevents deletes from freeing up the page for reuse until we have
515 * committed the delete transaction.
517 * If we didn't do this, then deleting something and reallocating it as
518 * data would allow the old block to be overwritten before the
519 * transaction committed (because we force data to disk before commit).
520 * This would lead to corruption if we crashed between overwriting the
521 * data and committing the delete.
523 * @@@ We may want to make this allocation behaviour conditional on
524 * data-writes at some point, and disable it for metadata allocations or
527 static int ext3_test_allocatable(ext3_grpblk_t nr
, struct buffer_head
*bh
)
530 struct journal_head
*jh
= bh2jh(bh
);
532 if (ext3_test_bit(nr
, bh
->b_data
))
535 jbd_lock_bh_state(bh
);
536 if (!jh
->b_committed_data
)
539 ret
= !ext3_test_bit(nr
, jh
->b_committed_data
);
540 jbd_unlock_bh_state(bh
);
545 bitmap_search_next_usable_block(ext3_grpblk_t start
, struct buffer_head
*bh
,
546 ext3_grpblk_t maxblocks
)
549 struct journal_head
*jh
= bh2jh(bh
);
552 * The bitmap search --- search forward alternately through the actual
553 * bitmap and the last-committed copy until we find a bit free in
556 while (start
< maxblocks
) {
557 next
= ext3_find_next_zero_bit(bh
->b_data
, maxblocks
, start
);
558 if (next
>= maxblocks
)
560 if (ext3_test_allocatable(next
, bh
))
562 jbd_lock_bh_state(bh
);
563 if (jh
->b_committed_data
)
564 start
= ext3_find_next_zero_bit(jh
->b_committed_data
,
566 jbd_unlock_bh_state(bh
);
572 * Find an allocatable block in a bitmap. We honour both the bitmap and
573 * its last-committed copy (if that exists), and perform the "most
574 * appropriate allocation" algorithm of looking for a free block near
575 * the initial goal; then for a free byte somewhere in the bitmap; then
576 * for any free bit in the bitmap.
579 find_next_usable_block(ext3_grpblk_t start
, struct buffer_head
*bh
,
580 ext3_grpblk_t maxblocks
)
582 ext3_grpblk_t here
, next
;
587 * The goal was occupied; search forward for a free
588 * block within the next XX blocks.
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..
594 ext3_grpblk_t 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
))
600 ext3_debug("Bit not found near goal\n");
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;
611 if (next
< maxblocks
&& next
>= start
&& ext3_test_allocatable(next
, bh
))
615 * The bitmap search --- search forward alternately through the actual
616 * bitmap and the last-committed copy until we find a bit free in
619 here
= bitmap_search_next_usable_block(here
, bh
, maxblocks
);
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
631 claim_block(spinlock_t
*lock
, ext3_grpblk_t block
, struct buffer_head
*bh
)
633 struct journal_head
*jh
= bh2jh(bh
);
636 if (ext3_set_bit_atomic(lock
, block
, bh
->b_data
))
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
);
645 jbd_unlock_bh_state(bh
);
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.
655 ext3_try_to_allocate(struct super_block
*sb
, handle_t
*handle
, int group
,
656 struct buffer_head
*bitmap_bh
, ext3_grpblk_t grp_goal
,
657 unsigned long *count
, struct ext3_reserve_window
*my_rsv
)
659 ext3_fsblk_t group_first_block
;
660 ext3_grpblk_t start
, end
;
661 unsigned long num
= 0;
663 /* we do allocation within the reservation window if we have a window */
665 group_first_block
= ext3_group_first_block_no(sb
, group
);
666 if (my_rsv
->_rsv_start
>= group_first_block
)
667 start
= my_rsv
->_rsv_start
- group_first_block
;
669 /* reservation window cross group boundary */
671 end
= my_rsv
->_rsv_end
- group_first_block
+ 1;
672 if (end
> EXT3_BLOCKS_PER_GROUP(sb
))
673 /* reservation window crosses group boundary */
674 end
= EXT3_BLOCKS_PER_GROUP(sb
);
675 if ((start
<= grp_goal
) && (grp_goal
< end
))
684 end
= EXT3_BLOCKS_PER_GROUP(sb
);
687 BUG_ON(start
> EXT3_BLOCKS_PER_GROUP(sb
));
690 if (grp_goal
< 0 || !ext3_test_allocatable(grp_goal
, bitmap_bh
)) {
691 grp_goal
= find_next_usable_block(start
, bitmap_bh
, end
);
697 for (i
= 0; i
< 7 && grp_goal
> start
&&
698 ext3_test_allocatable(grp_goal
- 1,
706 if (!claim_block(sb_bgl_lock(EXT3_SB(sb
), group
), grp_goal
, bitmap_bh
)) {
708 * The block was allocated by another thread, or it was
709 * allocated and then freed by another thread
719 while (num
< *count
&& grp_goal
< end
720 && ext3_test_allocatable(grp_goal
, bitmap_bh
)
721 && claim_block(sb_bgl_lock(EXT3_SB(sb
), group
), grp_goal
, bitmap_bh
)) {
726 return grp_goal
- num
;
733 * find_next_reservable_window():
734 * find a reservable space within the given range.
735 * It does not allocate the reservation window for now:
736 * alloc_new_reservation() will do the work later.
738 * @search_head: the head of the searching list;
739 * This is not necessarily the list head of the whole filesystem
741 * We have both head and start_block to assist the search
742 * for the reservable space. The list starts from head,
743 * but we will shift to the place where start_block is,
744 * then start from there, when looking for a reservable space.
746 * @size: the target new reservation window size
748 * @group_first_block: the first block we consider to start
749 * the real search from
752 * the maximum block number that our goal reservable space
753 * could start from. This is normally the last block in this
754 * group. The search will end when we found the start of next
755 * possible reservable space is out of this boundary.
756 * This could handle the cross boundary reservation window
759 * basically we search from the given range, rather than the whole
760 * reservation double linked list, (start_block, last_block)
761 * to find a free region that is of my size and has not
765 static int find_next_reservable_window(
766 struct ext3_reserve_window_node
*search_head
,
767 struct ext3_reserve_window_node
*my_rsv
,
768 struct super_block
* sb
,
769 ext3_fsblk_t start_block
,
770 ext3_fsblk_t last_block
)
772 struct rb_node
*next
;
773 struct ext3_reserve_window_node
*rsv
, *prev
;
775 int size
= my_rsv
->rsv_goal_size
;
777 /* TODO: make the start of the reservation window byte-aligned */
778 /* cur = *start_block & ~7;*/
785 if (cur
<= rsv
->rsv_end
)
786 cur
= rsv
->rsv_end
+ 1;
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.
794 * For now it will fail if we could not find the reservable
795 * space with expected-size (or more)...
797 if (cur
> last_block
)
798 return -1; /* fail */
801 next
= rb_next(&rsv
->rsv_node
);
802 rsv
= list_entry(next
,struct ext3_reserve_window_node
,rsv_node
);
805 * Reached the last reservation, we can just append to the
811 if (cur
+ size
<= rsv
->rsv_start
) {
813 * Found a reserveable space big enough. We could
814 * have a reservation across the group boundary here
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.
825 * or we found one reservable space in the middle of the list,
826 * return the reservation window that we could append to.
830 if ((prev
!= my_rsv
) && (!rsv_is_empty(&my_rsv
->rsv_window
)))
831 rsv_window_remove(sb
, my_rsv
);
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.
840 my_rsv
->rsv_start
= cur
;
841 my_rsv
->rsv_end
= cur
+ size
- 1;
842 my_rsv
->rsv_alloc_hit
= 0;
845 ext3_rsv_window_add(sb
, my_rsv
);
851 * alloc_new_reservation()--allocate a new reservation window
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.
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
864 * If the first free block is outside the reservable space, then
865 * start from the first free block, we search for next available
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.
872 * failed: we failed to find a reservation window in this group
874 * @rsv: the reservation
876 * @grp_goal: The goal (group-relative). It is where the search for a
877 * free reservable space should start from.
878 * if we have a grp_goal(grp_goal >0 ), then start from there,
879 * no grp_goal(grp_goal = -1), we start from the first block
882 * @sb: the super block
883 * @group: the group we are trying to allocate in
884 * @bitmap_bh: the block group block bitmap
887 static int alloc_new_reservation(struct ext3_reserve_window_node
*my_rsv
,
888 ext3_grpblk_t grp_goal
, struct super_block
*sb
,
889 unsigned int group
, struct buffer_head
*bitmap_bh
)
891 struct ext3_reserve_window_node
*search_head
;
892 ext3_fsblk_t group_first_block
, group_end_block
, start_block
;
893 ext3_grpblk_t first_free_block
;
894 struct rb_root
*fs_rsv_root
= &EXT3_SB(sb
)->s_rsv_window_root
;
897 spinlock_t
*rsv_lock
= &EXT3_SB(sb
)->s_rsv_window_lock
;
899 group_first_block
= ext3_group_first_block_no(sb
, group
);
900 group_end_block
= group_first_block
+ EXT3_BLOCKS_PER_GROUP(sb
) - 1;
903 start_block
= group_first_block
;
905 start_block
= grp_goal
+ group_first_block
;
907 size
= my_rsv
->rsv_goal_size
;
909 if (!rsv_is_empty(&my_rsv
->rsv_window
)) {
911 * if the old reservation is cross group boundary
912 * and if the goal is inside the old reservation window,
913 * we will come here when we just failed to allocate from
914 * the first part of the window. We still have another part
915 * that belongs to the next group. In this case, there is no
916 * point to discard our window and try to allocate a new one
917 * in this group(which will fail). we should
918 * keep the reservation window, just simply move on.
920 * Maybe we could shift the start block of the reservation
921 * window to the first block of next group.
924 if ((my_rsv
->rsv_start
<= group_end_block
) &&
925 (my_rsv
->rsv_end
> group_end_block
) &&
926 (start_block
>= my_rsv
->rsv_start
))
929 if ((my_rsv
->rsv_alloc_hit
>
930 (my_rsv
->rsv_end
- my_rsv
->rsv_start
+ 1) / 2)) {
932 * if we previously allocation hit ration is greater than half
933 * we double the size of reservation window next time
934 * otherwise keep the same
937 if (size
> EXT3_MAX_RESERVE_BLOCKS
)
938 size
= EXT3_MAX_RESERVE_BLOCKS
;
939 my_rsv
->rsv_goal_size
= size
;
945 * shift the search start to the window near the goal block
947 search_head
= search_reserve_window(fs_rsv_root
, start_block
);
950 * find_next_reservable_window() simply finds a reservable window
951 * inside the given range(start_block, group_end_block).
953 * To make sure the reservation window has a free bit inside it, we
954 * need to check the bitmap after we found a reservable window.
957 ret
= find_next_reservable_window(search_head
, my_rsv
, sb
,
958 start_block
, group_end_block
);
961 if (!rsv_is_empty(&my_rsv
->rsv_window
))
962 rsv_window_remove(sb
, my_rsv
);
963 spin_unlock(rsv_lock
);
968 * On success, find_next_reservable_window() returns the
969 * reservation window where there is a reservable space after it.
970 * Before we reserve this reservable space, we need
971 * to make sure there is at least a free block inside this region.
973 * searching the first free bit on the block bitmap and copy of
974 * last committed bitmap alternatively, until we found a allocatable
975 * block. Search start from the start block of the reservable space
978 spin_unlock(rsv_lock
);
979 first_free_block
= bitmap_search_next_usable_block(
980 my_rsv
->rsv_start
- group_first_block
,
981 bitmap_bh
, group_end_block
- group_first_block
+ 1);
983 if (first_free_block
< 0) {
985 * no free block left on the bitmap, no point
986 * to reserve the space. return failed.
989 if (!rsv_is_empty(&my_rsv
->rsv_window
))
990 rsv_window_remove(sb
, my_rsv
);
991 spin_unlock(rsv_lock
);
992 return -1; /* failed */
995 start_block
= first_free_block
+ group_first_block
;
997 * check if the first free block is within the
998 * free space we just reserved
1000 if (start_block
>= my_rsv
->rsv_start
&& start_block
< my_rsv
->rsv_end
)
1001 return 0; /* success */
1003 * if the first free bit we found is out of the reservable space
1004 * continue search for next reservable space,
1005 * start from where the free block is,
1006 * we also shift the list head to where we stopped last time
1008 search_head
= my_rsv
;
1009 spin_lock(rsv_lock
);
1013 static void try_to_extend_reservation(struct ext3_reserve_window_node
*my_rsv
,
1014 struct super_block
*sb
, int size
)
1016 struct ext3_reserve_window_node
*next_rsv
;
1017 struct rb_node
*next
;
1018 spinlock_t
*rsv_lock
= &EXT3_SB(sb
)->s_rsv_window_lock
;
1020 if (!spin_trylock(rsv_lock
))
1023 next
= rb_next(&my_rsv
->rsv_node
);
1026 my_rsv
->rsv_end
+= size
;
1028 next_rsv
= list_entry(next
, struct ext3_reserve_window_node
, rsv_node
);
1030 if ((next_rsv
->rsv_start
- my_rsv
->rsv_end
- 1) >= size
)
1031 my_rsv
->rsv_end
+= size
;
1033 my_rsv
->rsv_end
= next_rsv
->rsv_start
- 1;
1035 spin_unlock(rsv_lock
);
1039 * This is the main function used to allocate a new block and its reservation
1042 * Each time when a new block allocation is need, first try to allocate from
1043 * its own reservation. If it does not have a reservation window, instead of
1044 * looking for a free bit on bitmap first, then look up the reservation list to
1045 * see if it is inside somebody else's reservation window, we try to allocate a
1046 * reservation window for it starting from the goal first. Then do the block
1047 * allocation within the reservation window.
1049 * This will avoid keeping on searching the reservation list again and
1050 * again when somebody is looking for a free block (without
1051 * reservation), and there are lots of free blocks, but they are all
1054 * We use a sorted double linked list for the per-filesystem reservation list.
1055 * The insert, remove and find a free space(non-reserved) operations for the
1056 * sorted double linked list should be fast.
1059 static ext3_grpblk_t
1060 ext3_try_to_allocate_with_rsv(struct super_block
*sb
, handle_t
*handle
,
1061 unsigned int group
, struct buffer_head
*bitmap_bh
,
1062 ext3_grpblk_t grp_goal
,
1063 struct ext3_reserve_window_node
* my_rsv
,
1064 unsigned long *count
, int *errp
)
1066 ext3_fsblk_t group_first_block
;
1067 ext3_grpblk_t ret
= 0;
1069 unsigned long num
= *count
;
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.
1078 BUFFER_TRACE(bitmap_bh
, "get undo access for new block");
1079 fatal
= ext3_journal_get_undo_access(handle
, bitmap_bh
);
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
1091 if (my_rsv
== NULL
) {
1092 ret
= ext3_try_to_allocate(sb
, handle
, group
, bitmap_bh
,
1093 grp_goal
, count
, NULL
);
1097 * grp_goal is a group relative block number (if there is a goal)
1098 * 0 < grp_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
1102 group_first_block
= ext3_group_first_block_no(sb
, group
);
1105 * Basically we will allocate a new block from inode's reservation
1108 * We need to allocate a new reservation window, if:
1109 * a) inode does not have a reservation window; or
1110 * b) last attempt to allocate a block from existing reservation
1112 * c) we come here with a goal and with a reservation window
1114 * We do not need to allocate a new reservation window if we come here
1115 * at the beginning with a goal and the goal is inside the window, or
1116 * we don't have a goal but already have a reservation window.
1117 * then we could go to allocate from the reservation window directly.
1120 if (rsv_is_empty(&my_rsv
->rsv_window
) || (ret
< 0) ||
1121 !goal_in_my_reservation(&my_rsv
->rsv_window
, grp_goal
, group
, sb
)) {
1122 if (my_rsv
->rsv_goal_size
< *count
)
1123 my_rsv
->rsv_goal_size
= *count
;
1124 ret
= alloc_new_reservation(my_rsv
, grp_goal
, sb
,
1129 if (!goal_in_my_reservation(&my_rsv
->rsv_window
, grp_goal
, group
, sb
))
1131 } else if (grp_goal
> 0 && (my_rsv
->rsv_end
-grp_goal
+1) < *count
)
1132 try_to_extend_reservation(my_rsv
, sb
,
1133 *count
-my_rsv
->rsv_end
+ grp_goal
- 1);
1135 if ((my_rsv
->rsv_start
>= group_first_block
+ EXT3_BLOCKS_PER_GROUP(sb
))
1136 || (my_rsv
->rsv_end
< group_first_block
))
1138 ret
= ext3_try_to_allocate(sb
, handle
, group
, bitmap_bh
, grp_goal
,
1139 &num
, &my_rsv
->rsv_window
);
1141 my_rsv
->rsv_alloc_hit
+= num
;
1143 break; /* succeed */
1149 BUFFER_TRACE(bitmap_bh
, "journal_dirty_metadata for "
1151 fatal
= ext3_journal_dirty_metadata(handle
, bitmap_bh
);
1159 BUFFER_TRACE(bitmap_bh
, "journal_release_buffer");
1160 ext3_journal_release_buffer(handle
, bitmap_bh
);
1164 static int ext3_has_free_blocks(struct ext3_sb_info
*sbi
)
1166 ext3_fsblk_t free_blocks
, root_blocks
;
1168 free_blocks
= percpu_counter_read_positive(&sbi
->s_freeblocks_counter
);
1169 root_blocks
= le32_to_cpu(sbi
->s_es
->s_r_blocks_count
);
1170 if (free_blocks
< root_blocks
+ 1 && !capable(CAP_SYS_RESOURCE
) &&
1171 sbi
->s_resuid
!= current
->fsuid
&&
1172 (sbi
->s_resgid
== 0 || !in_group_p (sbi
->s_resgid
))) {
1179 * ext3_should_retry_alloc() is called when ENOSPC is returned, and if
1180 * it is profitable to retry the operation, this function will wait
1181 * for the current or commiting transaction to complete, and then
1184 int ext3_should_retry_alloc(struct super_block
*sb
, int *retries
)
1186 if (!ext3_has_free_blocks(EXT3_SB(sb
)) || (*retries
)++ > 3)
1189 jbd_debug(1, "%s: retrying operation after ENOSPC\n", sb
->s_id
);
1191 return journal_force_commit_nested(EXT3_SB(sb
)->s_journal
);
1195 * ext3_new_block uses a goal block to assist allocation. If the goal is
1196 * free, or there is a free block within 32 blocks of the goal, that block
1197 * is allocated. Otherwise a forward search is made for a free block; within
1198 * each block group the search first looks for an entire free byte in the block
1199 * bitmap, and then for any free bit if that fails.
1200 * This function also updates quota and i_blocks field.
1202 ext3_fsblk_t
ext3_new_blocks(handle_t
*handle
, struct inode
*inode
,
1203 ext3_fsblk_t goal
, unsigned long *count
, int *errp
)
1205 struct buffer_head
*bitmap_bh
= NULL
;
1206 struct buffer_head
*gdp_bh
;
1209 ext3_grpblk_t grp_target_blk
; /* blockgroup relative goal block */
1210 ext3_grpblk_t grp_alloc_blk
; /* blockgroup-relative allocated block*/
1211 ext3_fsblk_t ret_block
; /* filesyetem-wide allocated block */
1212 int bgi
; /* blockgroup iteration index */
1214 int performed_allocation
= 0;
1215 ext3_grpblk_t free_blocks
; /* number of free blocks in a group */
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;
1224 static int goal_hits
, goal_attempts
;
1226 unsigned long ngroups
;
1227 unsigned long num
= *count
;
1232 printk("ext3_new_block: nonexistent device");
1237 * Check quota for allocation of this block.
1239 if (DQUOT_ALLOC_BLOCK(inode
, num
)) {
1245 es
= EXT3_SB(sb
)->s_es
;
1246 ext3_debug("goal=%lu.\n", goal
);
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)
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
;
1259 if (!ext3_has_free_blocks(sbi
)) {
1265 * First, test whether the goal block is free.
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
);
1276 goal_group
= group_no
;
1278 free_blocks
= le16_to_cpu(gdp
->bg_free_blocks_count
);
1280 * if there is not enough free blocks to make a new resevation
1281 * turn off reservation for this allocation
1283 if (my_rsv
&& (free_blocks
< windowsz
)
1284 && (rsv_is_empty(&my_rsv
->rsv_window
)))
1287 if (free_blocks
> 0) {
1288 grp_target_blk
= ((goal
- le32_to_cpu(es
->s_first_data_block
)) %
1289 EXT3_BLOCKS_PER_GROUP(sb
));
1290 bitmap_bh
= read_block_bitmap(sb
, group_no
);
1293 grp_alloc_blk
= ext3_try_to_allocate_with_rsv(sb
, handle
,
1294 group_no
, bitmap_bh
, grp_target_blk
,
1295 my_rsv
, &num
, &fatal
);
1298 if (grp_alloc_blk
>= 0)
1302 ngroups
= EXT3_SB(sb
)->s_groups_count
;
1306 * Now search the rest of the groups. We assume that
1307 * i and gdp correctly point to the last group visited.
1309 for (bgi
= 0; bgi
< ngroups
; bgi
++) {
1311 if (group_no
>= ngroups
)
1313 gdp
= ext3_get_group_desc(sb
, group_no
, &gdp_bh
);
1318 free_blocks
= le16_to_cpu(gdp
->bg_free_blocks_count
);
1320 * skip this group if the number of
1321 * free blocks is less than half of the reservation
1324 if (free_blocks
<= (windowsz
/2))
1328 bitmap_bh
= read_block_bitmap(sb
, group_no
);
1332 * try to allocate block(s) from this group, without a goal(-1).
1334 grp_alloc_blk
= ext3_try_to_allocate_with_rsv(sb
, handle
,
1335 group_no
, bitmap_bh
, -1, my_rsv
,
1339 if (grp_alloc_blk
>= 0)
1343 * We may end up a bogus ealier ENOSPC error due to
1344 * filesystem is "full" of reservations, but
1345 * there maybe indeed free blocks avaliable on disk
1346 * In this case, we just forget about the reservations
1347 * just do block allocation as without reservations.
1351 group_no
= goal_group
;
1354 /* No space left on the device */
1360 ext3_debug("using block group %d(%d)\n",
1361 group_no
, gdp
->bg_free_blocks_count
);
1363 BUFFER_TRACE(gdp_bh
, "get_write_access");
1364 fatal
= ext3_journal_get_write_access(handle
, gdp_bh
);
1368 ret_block
= grp_alloc_blk
+ ext3_group_first_block_no(sb
, group_no
);
1370 if (in_range(le32_to_cpu(gdp
->bg_block_bitmap
), ret_block
, num
) ||
1371 in_range(le32_to_cpu(gdp
->bg_inode_bitmap
), ret_block
, num
) ||
1372 in_range(ret_block
, le32_to_cpu(gdp
->bg_inode_table
),
1373 EXT3_SB(sb
)->s_itb_per_group
) ||
1374 in_range(ret_block
+ num
- 1, le32_to_cpu(gdp
->bg_inode_table
),
1375 EXT3_SB(sb
)->s_itb_per_group
))
1376 ext3_error(sb
, "ext3_new_block",
1377 "Allocating block in system zone - "
1378 "blocks from "E3FSBLK
", length %lu",
1381 performed_allocation
= 1;
1383 #ifdef CONFIG_JBD_DEBUG
1385 struct buffer_head
*debug_bh
;
1387 /* Record bitmap buffer state in the newly allocated block */
1388 debug_bh
= sb_find_get_block(sb
, ret_block
);
1390 BUFFER_TRACE(debug_bh
, "state when allocated");
1391 BUFFER_TRACE2(debug_bh
, bitmap_bh
, "bitmap state");
1395 jbd_lock_bh_state(bitmap_bh
);
1396 spin_lock(sb_bgl_lock(sbi
, group_no
));
1397 if (buffer_jbd(bitmap_bh
) && bh2jh(bitmap_bh
)->b_committed_data
) {
1400 for (i
= 0; i
< num
; i
++) {
1401 if (ext3_test_bit(grp_alloc_blk
+i
,
1402 bh2jh(bitmap_bh
)->b_committed_data
)) {
1403 printk("%s: block was unexpectedly set in "
1404 "b_committed_data\n", __FUNCTION__
);
1408 ext3_debug("found bit %d\n", grp_alloc_blk
);
1409 spin_unlock(sb_bgl_lock(sbi
, group_no
));
1410 jbd_unlock_bh_state(bitmap_bh
);
1413 if (ret_block
+ num
- 1 >= le32_to_cpu(es
->s_blocks_count
)) {
1414 ext3_error(sb
, "ext3_new_block",
1415 "block("E3FSBLK
") >= blocks count(%d) - "
1416 "block_group = %d, es == %p ", ret_block
,
1417 le32_to_cpu(es
->s_blocks_count
), group_no
, es
);
1422 * It is up to the caller to add the new buffer to a journal
1423 * list of some description. We don't know in advance whether
1424 * the caller wants to use it as metadata or data.
1426 ext3_debug("allocating block %lu. Goal hits %d of %d.\n",
1427 ret_block
, goal_hits
, goal_attempts
);
1429 spin_lock(sb_bgl_lock(sbi
, group_no
));
1430 gdp
->bg_free_blocks_count
=
1431 cpu_to_le16(le16_to_cpu(gdp
->bg_free_blocks_count
) - num
);
1432 spin_unlock(sb_bgl_lock(sbi
, group_no
));
1433 percpu_counter_mod(&sbi
->s_freeblocks_counter
, -num
);
1435 BUFFER_TRACE(gdp_bh
, "journal_dirty_metadata for group descriptor");
1436 err
= ext3_journal_dirty_metadata(handle
, gdp_bh
);
1446 DQUOT_FREE_BLOCK(inode
, *count
-num
);
1455 ext3_std_error(sb
, fatal
);
1458 * Undo the block allocation
1460 if (!performed_allocation
)
1461 DQUOT_FREE_BLOCK(inode
, *count
);
1466 ext3_fsblk_t
ext3_new_block(handle_t
*handle
, struct inode
*inode
,
1467 ext3_fsblk_t goal
, int *errp
)
1469 unsigned long count
= 1;
1471 return ext3_new_blocks(handle
, inode
, goal
, &count
, errp
);
1474 ext3_fsblk_t
ext3_count_free_blocks(struct super_block
*sb
)
1476 ext3_fsblk_t desc_count
;
1477 struct ext3_group_desc
*gdp
;
1479 unsigned long ngroups
= EXT3_SB(sb
)->s_groups_count
;
1481 struct ext3_super_block
*es
;
1482 ext3_fsblk_t bitmap_count
;
1484 struct buffer_head
*bitmap_bh
= NULL
;
1486 es
= EXT3_SB(sb
)->s_es
;
1492 for (i
= 0; i
< ngroups
; i
++) {
1493 gdp
= ext3_get_group_desc(sb
, i
, NULL
);
1496 desc_count
+= le16_to_cpu(gdp
->bg_free_blocks_count
);
1498 bitmap_bh
= read_block_bitmap(sb
, i
);
1499 if (bitmap_bh
== NULL
)
1502 x
= ext3_count_free(bitmap_bh
, sb
->s_blocksize
);
1503 printk("group %d: stored = %d, counted = %lu\n",
1504 i
, le16_to_cpu(gdp
->bg_free_blocks_count
), x
);
1508 printk("ext3_count_free_blocks: stored = "E3FSBLK
1509 ", computed = "E3FSBLK
", "E3FSBLK
"\n",
1510 le32_to_cpu(es
->s_free_blocks_count
),
1511 desc_count
, bitmap_count
);
1512 return bitmap_count
;
1516 for (i
= 0; i
< ngroups
; i
++) {
1517 gdp
= ext3_get_group_desc(sb
, i
, NULL
);
1520 desc_count
+= le16_to_cpu(gdp
->bg_free_blocks_count
);
1528 block_in_use(ext3_fsblk_t block
, struct super_block
*sb
, unsigned char *map
)
1530 return ext3_test_bit ((block
-
1531 le32_to_cpu(EXT3_SB(sb
)->s_es
->s_first_data_block
)) %
1532 EXT3_BLOCKS_PER_GROUP(sb
), map
);
1535 static inline int test_root(int a
, int b
)
1544 static int ext3_group_sparse(int group
)
1550 return (test_root(group
, 7) || test_root(group
, 5) ||
1551 test_root(group
, 3));
1555 * ext3_bg_has_super - number of blocks used by the superblock in group
1556 * @sb: superblock for filesystem
1557 * @group: group number to check
1559 * Return the number of blocks used by the superblock (primary or backup)
1560 * in this group. Currently this will be only 0 or 1.
1562 int ext3_bg_has_super(struct super_block
*sb
, int group
)
1564 if (EXT3_HAS_RO_COMPAT_FEATURE(sb
,
1565 EXT3_FEATURE_RO_COMPAT_SPARSE_SUPER
) &&
1566 !ext3_group_sparse(group
))
1571 static unsigned long ext3_bg_num_gdb_meta(struct super_block
*sb
, int group
)
1573 unsigned long metagroup
= group
/ EXT3_DESC_PER_BLOCK(sb
);
1574 unsigned long first
= metagroup
* EXT3_DESC_PER_BLOCK(sb
);
1575 unsigned long last
= first
+ EXT3_DESC_PER_BLOCK(sb
) - 1;
1577 if (group
== first
|| group
== first
+ 1 || group
== last
)
1582 static unsigned long ext3_bg_num_gdb_nometa(struct super_block
*sb
, int group
)
1584 if (EXT3_HAS_RO_COMPAT_FEATURE(sb
,
1585 EXT3_FEATURE_RO_COMPAT_SPARSE_SUPER
) &&
1586 !ext3_group_sparse(group
))
1588 return EXT3_SB(sb
)->s_gdb_count
;
1592 * ext3_bg_num_gdb - number of blocks used by the group table in group
1593 * @sb: superblock for filesystem
1594 * @group: group number to check
1596 * Return the number of blocks used by the group descriptor table
1597 * (primary or backup) in this group. In the future there may be a
1598 * different number of descriptor blocks in each group.
1600 unsigned long ext3_bg_num_gdb(struct super_block
*sb
, int group
)
1602 unsigned long first_meta_bg
=
1603 le32_to_cpu(EXT3_SB(sb
)->s_es
->s_first_meta_bg
);
1604 unsigned long metagroup
= group
/ EXT3_DESC_PER_BLOCK(sb
);
1606 if (!EXT3_HAS_INCOMPAT_FEATURE(sb
,EXT3_FEATURE_INCOMPAT_META_BG
) ||
1607 metagroup
< first_meta_bg
)
1608 return ext3_bg_num_gdb_nometa(sb
,group
);
1610 return ext3_bg_num_gdb_meta(sb
,group
);