2 * linux/fs/ext4/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/jbd2.h>
18 #include <linux/ext4_fs.h>
19 #include <linux/ext4_jbd2.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 ext4_read_super).
39 #define in_range(b, first, len) ((b) >= (first) && (b) <= (first) + (len) - 1)
42 * ext4_get_group_desc() -- load group descriptor from disk
44 * @block_group: given block group
45 * @bh: pointer to the buffer head to store the block
48 struct ext4_group_desc
* ext4_get_group_desc(struct super_block
* sb
,
49 unsigned int block_group
,
50 struct buffer_head
** bh
)
52 unsigned long group_desc
;
54 struct ext4_group_desc
* desc
;
55 struct ext4_sb_info
*sbi
= EXT4_SB(sb
);
57 if (block_group
>= sbi
->s_groups_count
) {
58 ext4_error (sb
, "ext4_get_group_desc",
59 "block_group >= groups_count - "
60 "block_group = %d, groups_count = %lu",
61 block_group
, sbi
->s_groups_count
);
67 group_desc
= block_group
>> EXT4_DESC_PER_BLOCK_BITS(sb
);
68 offset
= block_group
& (EXT4_DESC_PER_BLOCK(sb
) - 1);
69 if (!sbi
->s_group_desc
[group_desc
]) {
70 ext4_error (sb
, "ext4_get_group_desc",
71 "Group descriptor not loaded - "
72 "block_group = %d, group_desc = %lu, desc = %lu",
73 block_group
, group_desc
, offset
);
77 desc
= (struct ext4_group_desc
*)(
78 (__u8
*)sbi
->s_group_desc
[group_desc
]->b_data
+
79 offset
* EXT4_DESC_SIZE(sb
));
81 *bh
= sbi
->s_group_desc
[group_desc
];
88 * @block_group: given block group
90 * Read the bitmap for a given block_group, reading into the specified
91 * slot in the superblock's bitmap cache.
93 * Return buffer_head on success or NULL in case of failure.
95 static struct buffer_head
*
96 read_block_bitmap(struct super_block
*sb
, unsigned int block_group
)
98 struct ext4_group_desc
* desc
;
99 struct buffer_head
* bh
= NULL
;
101 desc
= ext4_get_group_desc (sb
, block_group
, NULL
);
104 bh
= sb_bread(sb
, ext4_block_bitmap(sb
, desc
));
106 ext4_error (sb
, "read_block_bitmap",
107 "Cannot read block bitmap - "
108 "block_group = %d, block_bitmap = %llu",
110 ext4_block_bitmap(sb
, desc
));
115 * The reservation window structure operations
116 * --------------------------------------------
117 * Operations include:
118 * dump, find, add, remove, is_empty, find_next_reservable_window, etc.
120 * We use a red-black tree to represent per-filesystem reservation
126 * __rsv_window_dump() -- Dump the filesystem block allocation reservation map
127 * @rb_root: root of per-filesystem reservation rb tree
128 * @verbose: verbose mode
129 * @fn: function which wishes to dump the reservation map
131 * If verbose is turned on, it will print the whole block reservation
132 * windows(start, end). Otherwise, it will only print out the "bad" windows,
133 * those windows that overlap with their immediate neighbors.
136 static void __rsv_window_dump(struct rb_root
*root
, int verbose
,
140 struct ext4_reserve_window_node
*rsv
, *prev
;
148 printk("Block Allocation Reservation Windows Map (%s):\n", fn
);
150 rsv
= list_entry(n
, struct ext4_reserve_window_node
, rsv_node
);
152 printk("reservation window 0x%p "
153 "start: %llu, end: %llu\n",
154 rsv
, rsv
->rsv_start
, rsv
->rsv_end
);
155 if (rsv
->rsv_start
&& rsv
->rsv_start
>= rsv
->rsv_end
) {
156 printk("Bad reservation %p (start >= end)\n",
160 if (prev
&& prev
->rsv_end
>= rsv
->rsv_start
) {
161 printk("Bad reservation %p (prev->end >= start)\n",
167 printk("Restarting reservation walk in verbose mode\n");
175 printk("Window map complete.\n");
179 #define rsv_window_dump(root, verbose) \
180 __rsv_window_dump((root), (verbose), __FUNCTION__)
182 #define rsv_window_dump(root, verbose) do {} while (0)
186 * goal_in_my_reservation()
187 * @rsv: inode's reservation window
188 * @grp_goal: given goal block relative to the allocation block group
189 * @group: the current allocation block group
190 * @sb: filesystem super block
192 * Test if the given goal block (group relative) is within the file's
193 * own block reservation window range.
195 * If the reservation window is outside the goal allocation group, return 0;
196 * grp_goal (given goal block) could be -1, which means no specific
197 * goal block. In this case, always return 1.
198 * If the goal block is within the reservation window, return 1;
199 * otherwise, return 0;
202 goal_in_my_reservation(struct ext4_reserve_window
*rsv
, ext4_grpblk_t grp_goal
,
203 unsigned int group
, struct super_block
* sb
)
205 ext4_fsblk_t group_first_block
, group_last_block
;
207 group_first_block
= ext4_group_first_block_no(sb
, group
);
208 group_last_block
= group_first_block
+ (EXT4_BLOCKS_PER_GROUP(sb
) - 1);
210 if ((rsv
->_rsv_start
> group_last_block
) ||
211 (rsv
->_rsv_end
< group_first_block
))
213 if ((grp_goal
>= 0) && ((grp_goal
+ group_first_block
< rsv
->_rsv_start
)
214 || (grp_goal
+ group_first_block
> rsv
->_rsv_end
)))
220 * search_reserve_window()
221 * @rb_root: root of reservation tree
222 * @goal: target allocation block
224 * Find the reserved window which includes the goal, or the previous one
225 * if the goal is not in any window.
226 * Returns NULL if there are no windows or if all windows start after the goal.
228 static struct ext4_reserve_window_node
*
229 search_reserve_window(struct rb_root
*root
, ext4_fsblk_t goal
)
231 struct rb_node
*n
= root
->rb_node
;
232 struct ext4_reserve_window_node
*rsv
;
238 rsv
= rb_entry(n
, struct ext4_reserve_window_node
, rsv_node
);
240 if (goal
< rsv
->rsv_start
)
242 else if (goal
> rsv
->rsv_end
)
248 * We've fallen off the end of the tree: the goal wasn't inside
249 * any particular node. OK, the previous node must be to one
250 * side of the interval containing the goal. If it's the RHS,
251 * we need to back up one.
253 if (rsv
->rsv_start
> goal
) {
254 n
= rb_prev(&rsv
->rsv_node
);
255 rsv
= rb_entry(n
, struct ext4_reserve_window_node
, rsv_node
);
261 * ext4_rsv_window_add() -- Insert a window to the block reservation rb tree.
263 * @rsv: reservation window to add
265 * Must be called with rsv_lock hold.
267 void ext4_rsv_window_add(struct super_block
*sb
,
268 struct ext4_reserve_window_node
*rsv
)
270 struct rb_root
*root
= &EXT4_SB(sb
)->s_rsv_window_root
;
271 struct rb_node
*node
= &rsv
->rsv_node
;
272 ext4_fsblk_t start
= rsv
->rsv_start
;
274 struct rb_node
** p
= &root
->rb_node
;
275 struct rb_node
* parent
= NULL
;
276 struct ext4_reserve_window_node
*this;
281 this = rb_entry(parent
, struct ext4_reserve_window_node
, rsv_node
);
283 if (start
< this->rsv_start
)
285 else if (start
> this->rsv_end
)
288 rsv_window_dump(root
, 1);
293 rb_link_node(node
, parent
, p
);
294 rb_insert_color(node
, root
);
298 * ext4_rsv_window_remove() -- unlink a window from the reservation rb tree
300 * @rsv: reservation window to remove
302 * Mark the block reservation window as not allocated, and unlink it
303 * from the filesystem reservation window rb tree. Must be called with
306 static void rsv_window_remove(struct super_block
*sb
,
307 struct ext4_reserve_window_node
*rsv
)
309 rsv
->rsv_start
= EXT4_RESERVE_WINDOW_NOT_ALLOCATED
;
310 rsv
->rsv_end
= EXT4_RESERVE_WINDOW_NOT_ALLOCATED
;
311 rsv
->rsv_alloc_hit
= 0;
312 rb_erase(&rsv
->rsv_node
, &EXT4_SB(sb
)->s_rsv_window_root
);
316 * rsv_is_empty() -- Check if the reservation window is allocated.
317 * @rsv: given reservation window to check
319 * returns 1 if the end block is EXT4_RESERVE_WINDOW_NOT_ALLOCATED.
321 static inline int rsv_is_empty(struct ext4_reserve_window
*rsv
)
323 /* a valid reservation end block could not be 0 */
324 return rsv
->_rsv_end
== EXT4_RESERVE_WINDOW_NOT_ALLOCATED
;
328 * ext4_init_block_alloc_info()
329 * @inode: file inode structure
331 * Allocate and initialize the reservation window structure, and
332 * link the window to the ext4 inode structure at last
334 * The reservation window structure is only dynamically allocated
335 * and linked to ext4 inode the first time the open file
336 * needs a new block. So, before every ext4_new_block(s) call, for
337 * regular files, we should check whether the reservation window
338 * structure exists or not. In the latter case, this function is called.
339 * Fail to do so will result in block reservation being turned off for that
342 * This function is called from ext4_get_blocks_handle(), also called
343 * when setting the reservation window size through ioctl before the file
344 * is open for write (needs block allocation).
346 * Needs truncate_mutex protection prior to call this function.
348 void ext4_init_block_alloc_info(struct inode
*inode
)
350 struct ext4_inode_info
*ei
= EXT4_I(inode
);
351 struct ext4_block_alloc_info
*block_i
= ei
->i_block_alloc_info
;
352 struct super_block
*sb
= inode
->i_sb
;
354 block_i
= kmalloc(sizeof(*block_i
), GFP_NOFS
);
356 struct ext4_reserve_window_node
*rsv
= &block_i
->rsv_window_node
;
358 rsv
->rsv_start
= EXT4_RESERVE_WINDOW_NOT_ALLOCATED
;
359 rsv
->rsv_end
= EXT4_RESERVE_WINDOW_NOT_ALLOCATED
;
362 * if filesystem is mounted with NORESERVATION, the goal
363 * reservation window size is set to zero to indicate
364 * block reservation is off
366 if (!test_opt(sb
, RESERVATION
))
367 rsv
->rsv_goal_size
= 0;
369 rsv
->rsv_goal_size
= EXT4_DEFAULT_RESERVE_BLOCKS
;
370 rsv
->rsv_alloc_hit
= 0;
371 block_i
->last_alloc_logical_block
= 0;
372 block_i
->last_alloc_physical_block
= 0;
374 ei
->i_block_alloc_info
= block_i
;
378 * ext4_discard_reservation()
381 * Discard(free) block reservation window on last file close, or truncate
384 * It is being called in three cases:
385 * ext4_release_file(): last writer close the file
386 * ext4_clear_inode(): last iput(), when nobody link to this file.
387 * ext4_truncate(): when the block indirect map is about to change.
390 void ext4_discard_reservation(struct inode
*inode
)
392 struct ext4_inode_info
*ei
= EXT4_I(inode
);
393 struct ext4_block_alloc_info
*block_i
= ei
->i_block_alloc_info
;
394 struct ext4_reserve_window_node
*rsv
;
395 spinlock_t
*rsv_lock
= &EXT4_SB(inode
->i_sb
)->s_rsv_window_lock
;
400 rsv
= &block_i
->rsv_window_node
;
401 if (!rsv_is_empty(&rsv
->rsv_window
)) {
403 if (!rsv_is_empty(&rsv
->rsv_window
))
404 rsv_window_remove(inode
->i_sb
, rsv
);
405 spin_unlock(rsv_lock
);
410 * ext4_free_blocks_sb() -- Free given blocks and update quota
411 * @handle: handle to this transaction
413 * @block: start physcial block to free
414 * @count: number of blocks to free
415 * @pdquot_freed_blocks: pointer to quota
417 void ext4_free_blocks_sb(handle_t
*handle
, struct super_block
*sb
,
418 ext4_fsblk_t block
, unsigned long count
,
419 unsigned long *pdquot_freed_blocks
)
421 struct buffer_head
*bitmap_bh
= NULL
;
422 struct buffer_head
*gd_bh
;
423 unsigned long block_group
;
426 unsigned long overflow
;
427 struct ext4_group_desc
* desc
;
428 struct ext4_super_block
* es
;
429 struct ext4_sb_info
*sbi
;
431 ext4_grpblk_t group_freed
;
433 *pdquot_freed_blocks
= 0;
436 if (block
< le32_to_cpu(es
->s_first_data_block
) ||
437 block
+ count
< block
||
438 block
+ count
> ext4_blocks_count(es
)) {
439 ext4_error (sb
, "ext4_free_blocks",
440 "Freeing blocks not in datazone - "
441 "block = %llu, count = %lu", block
, count
);
445 ext4_debug ("freeing block(s) %llu-%llu\n", block
, block
+ count
- 1);
449 ext4_get_group_no_and_offset(sb
, block
, &block_group
, &bit
);
451 * Check to see if we are freeing blocks across a group
454 if (bit
+ count
> EXT4_BLOCKS_PER_GROUP(sb
)) {
455 overflow
= bit
+ count
- EXT4_BLOCKS_PER_GROUP(sb
);
459 bitmap_bh
= read_block_bitmap(sb
, block_group
);
462 desc
= ext4_get_group_desc (sb
, block_group
, &gd_bh
);
466 if (in_range(ext4_block_bitmap(sb
, desc
), block
, count
) ||
467 in_range(ext4_inode_bitmap(sb
, desc
), block
, count
) ||
468 in_range(block
, ext4_inode_table(sb
, desc
), sbi
->s_itb_per_group
) ||
469 in_range(block
+ count
- 1, ext4_inode_table(sb
, desc
),
470 sbi
->s_itb_per_group
))
471 ext4_error (sb
, "ext4_free_blocks",
472 "Freeing blocks in system zones - "
473 "Block = %llu, count = %lu",
477 * We are about to start releasing blocks in the bitmap,
478 * so we need undo access.
480 /* @@@ check errors */
481 BUFFER_TRACE(bitmap_bh
, "getting undo access");
482 err
= ext4_journal_get_undo_access(handle
, bitmap_bh
);
487 * We are about to modify some metadata. Call the journal APIs
488 * to unshare ->b_data if a currently-committing transaction is
491 BUFFER_TRACE(gd_bh
, "get_write_access");
492 err
= ext4_journal_get_write_access(handle
, gd_bh
);
496 jbd_lock_bh_state(bitmap_bh
);
498 for (i
= 0, group_freed
= 0; i
< count
; i
++) {
500 * An HJ special. This is expensive...
502 #ifdef CONFIG_JBD_DEBUG
503 jbd_unlock_bh_state(bitmap_bh
);
505 struct buffer_head
*debug_bh
;
506 debug_bh
= sb_find_get_block(sb
, block
+ i
);
508 BUFFER_TRACE(debug_bh
, "Deleted!");
509 if (!bh2jh(bitmap_bh
)->b_committed_data
)
510 BUFFER_TRACE(debug_bh
,
511 "No commited data in bitmap");
512 BUFFER_TRACE2(debug_bh
, bitmap_bh
, "bitmap");
516 jbd_lock_bh_state(bitmap_bh
);
518 if (need_resched()) {
519 jbd_unlock_bh_state(bitmap_bh
);
521 jbd_lock_bh_state(bitmap_bh
);
523 /* @@@ This prevents newly-allocated data from being
524 * freed and then reallocated within the same
527 * Ideally we would want to allow that to happen, but to
528 * do so requires making jbd2_journal_forget() capable of
529 * revoking the queued write of a data block, which
530 * implies blocking on the journal lock. *forget()
531 * cannot block due to truncate races.
533 * Eventually we can fix this by making jbd2_journal_forget()
534 * return a status indicating whether or not it was able
535 * to revoke the buffer. On successful revoke, it is
536 * safe not to set the allocation bit in the committed
537 * bitmap, because we know that there is no outstanding
538 * activity on the buffer any more and so it is safe to
541 BUFFER_TRACE(bitmap_bh
, "set in b_committed_data");
542 J_ASSERT_BH(bitmap_bh
,
543 bh2jh(bitmap_bh
)->b_committed_data
!= NULL
);
544 ext4_set_bit_atomic(sb_bgl_lock(sbi
, block_group
), bit
+ i
,
545 bh2jh(bitmap_bh
)->b_committed_data
);
548 * We clear the bit in the bitmap after setting the committed
549 * data bit, because this is the reverse order to that which
550 * the allocator uses.
552 BUFFER_TRACE(bitmap_bh
, "clear bit");
553 if (!ext4_clear_bit_atomic(sb_bgl_lock(sbi
, block_group
),
554 bit
+ i
, bitmap_bh
->b_data
)) {
555 jbd_unlock_bh_state(bitmap_bh
);
556 ext4_error(sb
, __FUNCTION__
,
557 "bit already cleared for block %llu",
558 (ext4_fsblk_t
)(block
+ i
));
559 jbd_lock_bh_state(bitmap_bh
);
560 BUFFER_TRACE(bitmap_bh
, "bit already cleared");
565 jbd_unlock_bh_state(bitmap_bh
);
567 spin_lock(sb_bgl_lock(sbi
, block_group
));
568 desc
->bg_free_blocks_count
=
569 cpu_to_le16(le16_to_cpu(desc
->bg_free_blocks_count
) +
571 spin_unlock(sb_bgl_lock(sbi
, block_group
));
572 percpu_counter_mod(&sbi
->s_freeblocks_counter
, count
);
574 /* We dirtied the bitmap block */
575 BUFFER_TRACE(bitmap_bh
, "dirtied bitmap block");
576 err
= ext4_journal_dirty_metadata(handle
, bitmap_bh
);
578 /* And the group descriptor block */
579 BUFFER_TRACE(gd_bh
, "dirtied group descriptor block");
580 ret
= ext4_journal_dirty_metadata(handle
, gd_bh
);
582 *pdquot_freed_blocks
+= group_freed
;
584 if (overflow
&& !err
) {
592 ext4_std_error(sb
, err
);
597 * ext4_free_blocks() -- Free given blocks and update quota
598 * @handle: handle for this transaction
600 * @block: start physical block to free
601 * @count: number of blocks to count
603 void ext4_free_blocks(handle_t
*handle
, struct inode
*inode
,
604 ext4_fsblk_t block
, unsigned long count
)
606 struct super_block
* sb
;
607 unsigned long dquot_freed_blocks
;
611 printk ("ext4_free_blocks: nonexistent device");
614 ext4_free_blocks_sb(handle
, sb
, block
, count
, &dquot_freed_blocks
);
615 if (dquot_freed_blocks
)
616 DQUOT_FREE_BLOCK(inode
, dquot_freed_blocks
);
621 * ext4_test_allocatable()
622 * @nr: given allocation block group
623 * @bh: bufferhead contains the bitmap of the given block group
625 * For ext4 allocations, we must not reuse any blocks which are
626 * allocated in the bitmap buffer's "last committed data" copy. This
627 * prevents deletes from freeing up the page for reuse until we have
628 * committed the delete transaction.
630 * If we didn't do this, then deleting something and reallocating it as
631 * data would allow the old block to be overwritten before the
632 * transaction committed (because we force data to disk before commit).
633 * This would lead to corruption if we crashed between overwriting the
634 * data and committing the delete.
636 * @@@ We may want to make this allocation behaviour conditional on
637 * data-writes at some point, and disable it for metadata allocations or
640 static int ext4_test_allocatable(ext4_grpblk_t nr
, struct buffer_head
*bh
)
643 struct journal_head
*jh
= bh2jh(bh
);
645 if (ext4_test_bit(nr
, bh
->b_data
))
648 jbd_lock_bh_state(bh
);
649 if (!jh
->b_committed_data
)
652 ret
= !ext4_test_bit(nr
, jh
->b_committed_data
);
653 jbd_unlock_bh_state(bh
);
658 * bitmap_search_next_usable_block()
659 * @start: the starting block (group relative) of the search
660 * @bh: bufferhead contains the block group bitmap
661 * @maxblocks: the ending block (group relative) of the reservation
663 * The bitmap search --- search forward alternately through the actual
664 * bitmap on disk and the last-committed copy in journal, until we find a
665 * bit free in both bitmaps.
668 bitmap_search_next_usable_block(ext4_grpblk_t start
, struct buffer_head
*bh
,
669 ext4_grpblk_t maxblocks
)
672 struct journal_head
*jh
= bh2jh(bh
);
674 while (start
< maxblocks
) {
675 next
= ext4_find_next_zero_bit(bh
->b_data
, maxblocks
, start
);
676 if (next
>= maxblocks
)
678 if (ext4_test_allocatable(next
, bh
))
680 jbd_lock_bh_state(bh
);
681 if (jh
->b_committed_data
)
682 start
= ext4_find_next_zero_bit(jh
->b_committed_data
,
684 jbd_unlock_bh_state(bh
);
690 * find_next_usable_block()
691 * @start: the starting block (group relative) to find next
692 * allocatable block in bitmap.
693 * @bh: bufferhead contains the block group bitmap
694 * @maxblocks: the ending block (group relative) for the search
696 * Find an allocatable block in a bitmap. We honor both the bitmap and
697 * its last-committed copy (if that exists), and perform the "most
698 * appropriate allocation" algorithm of looking for a free block near
699 * the initial goal; then for a free byte somewhere in the bitmap; then
700 * for any free bit in the bitmap.
703 find_next_usable_block(ext4_grpblk_t start
, struct buffer_head
*bh
,
704 ext4_grpblk_t maxblocks
)
706 ext4_grpblk_t here
, next
;
711 * The goal was occupied; search forward for a free
712 * block within the next XX blocks.
714 * end_goal is more or less random, but it has to be
715 * less than EXT4_BLOCKS_PER_GROUP. Aligning up to the
716 * next 64-bit boundary is simple..
718 ext4_grpblk_t end_goal
= (start
+ 63) & ~63;
719 if (end_goal
> maxblocks
)
720 end_goal
= maxblocks
;
721 here
= ext4_find_next_zero_bit(bh
->b_data
, end_goal
, start
);
722 if (here
< end_goal
&& ext4_test_allocatable(here
, bh
))
724 ext4_debug("Bit not found near goal\n");
731 p
= ((char *)bh
->b_data
) + (here
>> 3);
732 r
= memscan(p
, 0, (maxblocks
- here
+ 7) >> 3);
733 next
= (r
- ((char *)bh
->b_data
)) << 3;
735 if (next
< maxblocks
&& next
>= start
&& ext4_test_allocatable(next
, bh
))
739 * The bitmap search --- search forward alternately through the actual
740 * bitmap and the last-committed copy until we find a bit free in
743 here
= bitmap_search_next_usable_block(here
, bh
, maxblocks
);
749 * @block: the free block (group relative) to allocate
750 * @bh: the bufferhead containts the block group bitmap
752 * We think we can allocate this block in this bitmap. Try to set the bit.
753 * If that succeeds then check that nobody has allocated and then freed the
754 * block since we saw that is was not marked in b_committed_data. If it _was_
755 * allocated and freed then clear the bit in the bitmap again and return
759 claim_block(spinlock_t
*lock
, ext4_grpblk_t block
, struct buffer_head
*bh
)
761 struct journal_head
*jh
= bh2jh(bh
);
764 if (ext4_set_bit_atomic(lock
, block
, bh
->b_data
))
766 jbd_lock_bh_state(bh
);
767 if (jh
->b_committed_data
&& ext4_test_bit(block
,jh
->b_committed_data
)) {
768 ext4_clear_bit_atomic(lock
, block
, bh
->b_data
);
773 jbd_unlock_bh_state(bh
);
778 * ext4_try_to_allocate()
780 * @handle: handle to this transaction
781 * @group: given allocation block group
782 * @bitmap_bh: bufferhead holds the block bitmap
783 * @grp_goal: given target block within the group
784 * @count: target number of blocks to allocate
785 * @my_rsv: reservation window
787 * Attempt to allocate blocks within a give range. Set the range of allocation
788 * first, then find the first free bit(s) from the bitmap (within the range),
789 * and at last, allocate the blocks by claiming the found free bit as allocated.
791 * To set the range of this allocation:
792 * if there is a reservation window, only try to allocate block(s) from the
793 * file's own reservation window;
794 * Otherwise, the allocation range starts from the give goal block, ends at
795 * the block group's last block.
797 * If we failed to allocate the desired block then we may end up crossing to a
798 * new bitmap. In that case we must release write access to the old one via
799 * ext4_journal_release_buffer(), else we'll run out of credits.
802 ext4_try_to_allocate(struct super_block
*sb
, handle_t
*handle
, int group
,
803 struct buffer_head
*bitmap_bh
, ext4_grpblk_t grp_goal
,
804 unsigned long *count
, struct ext4_reserve_window
*my_rsv
)
806 ext4_fsblk_t group_first_block
;
807 ext4_grpblk_t start
, end
;
808 unsigned long num
= 0;
810 /* we do allocation within the reservation window if we have a window */
812 group_first_block
= ext4_group_first_block_no(sb
, group
);
813 if (my_rsv
->_rsv_start
>= group_first_block
)
814 start
= my_rsv
->_rsv_start
- group_first_block
;
816 /* reservation window cross group boundary */
818 end
= my_rsv
->_rsv_end
- group_first_block
+ 1;
819 if (end
> EXT4_BLOCKS_PER_GROUP(sb
))
820 /* reservation window crosses group boundary */
821 end
= EXT4_BLOCKS_PER_GROUP(sb
);
822 if ((start
<= grp_goal
) && (grp_goal
< end
))
831 end
= EXT4_BLOCKS_PER_GROUP(sb
);
834 BUG_ON(start
> EXT4_BLOCKS_PER_GROUP(sb
));
837 if (grp_goal
< 0 || !ext4_test_allocatable(grp_goal
, bitmap_bh
)) {
838 grp_goal
= find_next_usable_block(start
, bitmap_bh
, end
);
844 for (i
= 0; i
< 7 && grp_goal
> start
&&
845 ext4_test_allocatable(grp_goal
- 1,
853 if (!claim_block(sb_bgl_lock(EXT4_SB(sb
), group
),
854 grp_goal
, bitmap_bh
)) {
856 * The block was allocated by another thread, or it was
857 * allocated and then freed by another thread
867 while (num
< *count
&& grp_goal
< end
868 && ext4_test_allocatable(grp_goal
, bitmap_bh
)
869 && claim_block(sb_bgl_lock(EXT4_SB(sb
), group
),
870 grp_goal
, bitmap_bh
)) {
875 return grp_goal
- num
;
882 * find_next_reservable_window():
883 * find a reservable space within the given range.
884 * It does not allocate the reservation window for now:
885 * alloc_new_reservation() will do the work later.
887 * @search_head: the head of the searching list;
888 * This is not necessarily the list head of the whole filesystem
890 * We have both head and start_block to assist the search
891 * for the reservable space. The list starts from head,
892 * but we will shift to the place where start_block is,
893 * then start from there, when looking for a reservable space.
895 * @size: the target new reservation window size
897 * @group_first_block: the first block we consider to start
898 * the real search from
901 * the maximum block number that our goal reservable space
902 * could start from. This is normally the last block in this
903 * group. The search will end when we found the start of next
904 * possible reservable space is out of this boundary.
905 * This could handle the cross boundary reservation window
908 * basically we search from the given range, rather than the whole
909 * reservation double linked list, (start_block, last_block)
910 * to find a free region that is of my size and has not
914 static int find_next_reservable_window(
915 struct ext4_reserve_window_node
*search_head
,
916 struct ext4_reserve_window_node
*my_rsv
,
917 struct super_block
* sb
,
918 ext4_fsblk_t start_block
,
919 ext4_fsblk_t last_block
)
921 struct rb_node
*next
;
922 struct ext4_reserve_window_node
*rsv
, *prev
;
924 int size
= my_rsv
->rsv_goal_size
;
926 /* TODO: make the start of the reservation window byte-aligned */
927 /* cur = *start_block & ~7;*/
934 if (cur
<= rsv
->rsv_end
)
935 cur
= rsv
->rsv_end
+ 1;
938 * in the case we could not find a reservable space
939 * that is what is expected, during the re-search, we could
940 * remember what's the largest reservable space we could have
941 * and return that one.
943 * For now it will fail if we could not find the reservable
944 * space with expected-size (or more)...
946 if (cur
> last_block
)
947 return -1; /* fail */
950 next
= rb_next(&rsv
->rsv_node
);
951 rsv
= list_entry(next
,struct ext4_reserve_window_node
,rsv_node
);
954 * Reached the last reservation, we can just append to the
960 if (cur
+ size
<= rsv
->rsv_start
) {
962 * Found a reserveable space big enough. We could
963 * have a reservation across the group boundary here
969 * we come here either :
970 * when we reach the end of the whole list,
971 * and there is empty reservable space after last entry in the list.
972 * append it to the end of the list.
974 * or we found one reservable space in the middle of the list,
975 * return the reservation window that we could append to.
979 if ((prev
!= my_rsv
) && (!rsv_is_empty(&my_rsv
->rsv_window
)))
980 rsv_window_remove(sb
, my_rsv
);
983 * Let's book the whole avaliable window for now. We will check the
984 * disk bitmap later and then, if there are free blocks then we adjust
985 * the window size if it's larger than requested.
986 * Otherwise, we will remove this node from the tree next time
987 * call find_next_reservable_window.
989 my_rsv
->rsv_start
= cur
;
990 my_rsv
->rsv_end
= cur
+ size
- 1;
991 my_rsv
->rsv_alloc_hit
= 0;
994 ext4_rsv_window_add(sb
, my_rsv
);
1000 * alloc_new_reservation()--allocate a new reservation window
1002 * To make a new reservation, we search part of the filesystem
1003 * reservation list (the list that inside the group). We try to
1004 * allocate a new reservation window near the allocation goal,
1005 * or the beginning of the group, if there is no goal.
1007 * We first find a reservable space after the goal, then from
1008 * there, we check the bitmap for the first free block after
1009 * it. If there is no free block until the end of group, then the
1010 * whole group is full, we failed. Otherwise, check if the free
1011 * block is inside the expected reservable space, if so, we
1013 * If the first free block is outside the reservable space, then
1014 * start from the first free block, we search for next available
1017 * on succeed, a new reservation will be found and inserted into the list
1018 * It contains at least one free block, and it does not overlap with other
1019 * reservation windows.
1021 * failed: we failed to find a reservation window in this group
1023 * @rsv: the reservation
1025 * @grp_goal: The goal (group-relative). It is where the search for a
1026 * free reservable space should start from.
1027 * if we have a grp_goal(grp_goal >0 ), then start from there,
1028 * no grp_goal(grp_goal = -1), we start from the first block
1031 * @sb: the super block
1032 * @group: the group we are trying to allocate in
1033 * @bitmap_bh: the block group block bitmap
1036 static int alloc_new_reservation(struct ext4_reserve_window_node
*my_rsv
,
1037 ext4_grpblk_t grp_goal
, struct super_block
*sb
,
1038 unsigned int group
, struct buffer_head
*bitmap_bh
)
1040 struct ext4_reserve_window_node
*search_head
;
1041 ext4_fsblk_t group_first_block
, group_end_block
, start_block
;
1042 ext4_grpblk_t first_free_block
;
1043 struct rb_root
*fs_rsv_root
= &EXT4_SB(sb
)->s_rsv_window_root
;
1046 spinlock_t
*rsv_lock
= &EXT4_SB(sb
)->s_rsv_window_lock
;
1048 group_first_block
= ext4_group_first_block_no(sb
, group
);
1049 group_end_block
= group_first_block
+ (EXT4_BLOCKS_PER_GROUP(sb
) - 1);
1052 start_block
= group_first_block
;
1054 start_block
= grp_goal
+ group_first_block
;
1056 size
= my_rsv
->rsv_goal_size
;
1058 if (!rsv_is_empty(&my_rsv
->rsv_window
)) {
1060 * if the old reservation is cross group boundary
1061 * and if the goal is inside the old reservation window,
1062 * we will come here when we just failed to allocate from
1063 * the first part of the window. We still have another part
1064 * that belongs to the next group. In this case, there is no
1065 * point to discard our window and try to allocate a new one
1066 * in this group(which will fail). we should
1067 * keep the reservation window, just simply move on.
1069 * Maybe we could shift the start block of the reservation
1070 * window to the first block of next group.
1073 if ((my_rsv
->rsv_start
<= group_end_block
) &&
1074 (my_rsv
->rsv_end
> group_end_block
) &&
1075 (start_block
>= my_rsv
->rsv_start
))
1078 if ((my_rsv
->rsv_alloc_hit
>
1079 (my_rsv
->rsv_end
- my_rsv
->rsv_start
+ 1) / 2)) {
1081 * if the previously allocation hit ratio is
1082 * greater than 1/2, then we double the size of
1083 * the reservation window the next time,
1084 * otherwise we keep the same size window
1087 if (size
> EXT4_MAX_RESERVE_BLOCKS
)
1088 size
= EXT4_MAX_RESERVE_BLOCKS
;
1089 my_rsv
->rsv_goal_size
= size
;
1093 spin_lock(rsv_lock
);
1095 * shift the search start to the window near the goal block
1097 search_head
= search_reserve_window(fs_rsv_root
, start_block
);
1100 * find_next_reservable_window() simply finds a reservable window
1101 * inside the given range(start_block, group_end_block).
1103 * To make sure the reservation window has a free bit inside it, we
1104 * need to check the bitmap after we found a reservable window.
1107 ret
= find_next_reservable_window(search_head
, my_rsv
, sb
,
1108 start_block
, group_end_block
);
1111 if (!rsv_is_empty(&my_rsv
->rsv_window
))
1112 rsv_window_remove(sb
, my_rsv
);
1113 spin_unlock(rsv_lock
);
1118 * On success, find_next_reservable_window() returns the
1119 * reservation window where there is a reservable space after it.
1120 * Before we reserve this reservable space, we need
1121 * to make sure there is at least a free block inside this region.
1123 * searching the first free bit on the block bitmap and copy of
1124 * last committed bitmap alternatively, until we found a allocatable
1125 * block. Search start from the start block of the reservable space
1128 spin_unlock(rsv_lock
);
1129 first_free_block
= bitmap_search_next_usable_block(
1130 my_rsv
->rsv_start
- group_first_block
,
1131 bitmap_bh
, group_end_block
- group_first_block
+ 1);
1133 if (first_free_block
< 0) {
1135 * no free block left on the bitmap, no point
1136 * to reserve the space. return failed.
1138 spin_lock(rsv_lock
);
1139 if (!rsv_is_empty(&my_rsv
->rsv_window
))
1140 rsv_window_remove(sb
, my_rsv
);
1141 spin_unlock(rsv_lock
);
1142 return -1; /* failed */
1145 start_block
= first_free_block
+ group_first_block
;
1147 * check if the first free block is within the
1148 * free space we just reserved
1150 if (start_block
>= my_rsv
->rsv_start
&& start_block
< my_rsv
->rsv_end
)
1151 return 0; /* success */
1153 * if the first free bit we found is out of the reservable space
1154 * continue search for next reservable space,
1155 * start from where the free block is,
1156 * we also shift the list head to where we stopped last time
1158 search_head
= my_rsv
;
1159 spin_lock(rsv_lock
);
1164 * try_to_extend_reservation()
1165 * @my_rsv: given reservation window
1167 * @size: the delta to extend
1169 * Attempt to expand the reservation window large enough to have
1170 * required number of free blocks
1172 * Since ext4_try_to_allocate() will always allocate blocks within
1173 * the reservation window range, if the window size is too small,
1174 * multiple blocks allocation has to stop at the end of the reservation
1175 * window. To make this more efficient, given the total number of
1176 * blocks needed and the current size of the window, we try to
1177 * expand the reservation window size if necessary on a best-effort
1178 * basis before ext4_new_blocks() tries to allocate blocks,
1180 static void try_to_extend_reservation(struct ext4_reserve_window_node
*my_rsv
,
1181 struct super_block
*sb
, int size
)
1183 struct ext4_reserve_window_node
*next_rsv
;
1184 struct rb_node
*next
;
1185 spinlock_t
*rsv_lock
= &EXT4_SB(sb
)->s_rsv_window_lock
;
1187 if (!spin_trylock(rsv_lock
))
1190 next
= rb_next(&my_rsv
->rsv_node
);
1193 my_rsv
->rsv_end
+= size
;
1195 next_rsv
= list_entry(next
, struct ext4_reserve_window_node
, rsv_node
);
1197 if ((next_rsv
->rsv_start
- my_rsv
->rsv_end
- 1) >= size
)
1198 my_rsv
->rsv_end
+= size
;
1200 my_rsv
->rsv_end
= next_rsv
->rsv_start
- 1;
1202 spin_unlock(rsv_lock
);
1206 * ext4_try_to_allocate_with_rsv()
1208 * @handle: handle to this transaction
1209 * @group: given allocation block group
1210 * @bitmap_bh: bufferhead holds the block bitmap
1211 * @grp_goal: given target block within the group
1212 * @count: target number of blocks to allocate
1213 * @my_rsv: reservation window
1214 * @errp: pointer to store the error code
1216 * This is the main function used to allocate a new block and its reservation
1219 * Each time when a new block allocation is need, first try to allocate from
1220 * its own reservation. If it does not have a reservation window, instead of
1221 * looking for a free bit on bitmap first, then look up the reservation list to
1222 * see if it is inside somebody else's reservation window, we try to allocate a
1223 * reservation window for it starting from the goal first. Then do the block
1224 * allocation within the reservation window.
1226 * This will avoid keeping on searching the reservation list again and
1227 * again when somebody is looking for a free block (without
1228 * reservation), and there are lots of free blocks, but they are all
1231 * We use a red-black tree for the per-filesystem reservation list.
1234 static ext4_grpblk_t
1235 ext4_try_to_allocate_with_rsv(struct super_block
*sb
, handle_t
*handle
,
1236 unsigned int group
, struct buffer_head
*bitmap_bh
,
1237 ext4_grpblk_t grp_goal
,
1238 struct ext4_reserve_window_node
* my_rsv
,
1239 unsigned long *count
, int *errp
)
1241 ext4_fsblk_t group_first_block
, group_last_block
;
1242 ext4_grpblk_t ret
= 0;
1244 unsigned long num
= *count
;
1249 * Make sure we use undo access for the bitmap, because it is critical
1250 * that we do the frozen_data COW on bitmap buffers in all cases even
1251 * if the buffer is in BJ_Forget state in the committing transaction.
1253 BUFFER_TRACE(bitmap_bh
, "get undo access for new block");
1254 fatal
= ext4_journal_get_undo_access(handle
, bitmap_bh
);
1261 * we don't deal with reservation when
1262 * filesystem is mounted without reservation
1263 * or the file is not a regular file
1264 * or last attempt to allocate a block with reservation turned on failed
1266 if (my_rsv
== NULL
) {
1267 ret
= ext4_try_to_allocate(sb
, handle
, group
, bitmap_bh
,
1268 grp_goal
, count
, NULL
);
1272 * grp_goal is a group relative block number (if there is a goal)
1273 * 0 < grp_goal < EXT4_BLOCKS_PER_GROUP(sb)
1274 * first block is a filesystem wide block number
1275 * first block is the block number of the first block in this group
1277 group_first_block
= ext4_group_first_block_no(sb
, group
);
1278 group_last_block
= group_first_block
+ (EXT4_BLOCKS_PER_GROUP(sb
) - 1);
1281 * Basically we will allocate a new block from inode's reservation
1284 * We need to allocate a new reservation window, if:
1285 * a) inode does not have a reservation window; or
1286 * b) last attempt to allocate a block from existing reservation
1288 * c) we come here with a goal and with a reservation window
1290 * We do not need to allocate a new reservation window if we come here
1291 * at the beginning with a goal and the goal is inside the window, or
1292 * we don't have a goal but already have a reservation window.
1293 * then we could go to allocate from the reservation window directly.
1296 if (rsv_is_empty(&my_rsv
->rsv_window
) || (ret
< 0) ||
1297 !goal_in_my_reservation(&my_rsv
->rsv_window
,
1298 grp_goal
, group
, sb
)) {
1299 if (my_rsv
->rsv_goal_size
< *count
)
1300 my_rsv
->rsv_goal_size
= *count
;
1301 ret
= alloc_new_reservation(my_rsv
, grp_goal
, sb
,
1306 if (!goal_in_my_reservation(&my_rsv
->rsv_window
,
1307 grp_goal
, group
, sb
))
1309 } else if (grp_goal
> 0 &&
1310 (my_rsv
->rsv_end
-grp_goal
+1) < *count
)
1311 try_to_extend_reservation(my_rsv
, sb
,
1312 *count
-my_rsv
->rsv_end
+ grp_goal
- 1);
1314 if ((my_rsv
->rsv_start
> group_last_block
) ||
1315 (my_rsv
->rsv_end
< group_first_block
)) {
1316 rsv_window_dump(&EXT4_SB(sb
)->s_rsv_window_root
, 1);
1319 ret
= ext4_try_to_allocate(sb
, handle
, group
, bitmap_bh
,
1320 grp_goal
, &num
, &my_rsv
->rsv_window
);
1322 my_rsv
->rsv_alloc_hit
+= num
;
1324 break; /* succeed */
1330 BUFFER_TRACE(bitmap_bh
, "journal_dirty_metadata for "
1332 fatal
= ext4_journal_dirty_metadata(handle
, bitmap_bh
);
1340 BUFFER_TRACE(bitmap_bh
, "journal_release_buffer");
1341 ext4_journal_release_buffer(handle
, bitmap_bh
);
1346 * ext4_has_free_blocks()
1347 * @sbi: in-core super block structure.
1349 * Check if filesystem has at least 1 free block available for allocation.
1351 static int ext4_has_free_blocks(struct ext4_sb_info
*sbi
)
1353 ext4_fsblk_t free_blocks
, root_blocks
;
1355 free_blocks
= percpu_counter_read_positive(&sbi
->s_freeblocks_counter
);
1356 root_blocks
= ext4_r_blocks_count(sbi
->s_es
);
1357 if (free_blocks
< root_blocks
+ 1 && !capable(CAP_SYS_RESOURCE
) &&
1358 sbi
->s_resuid
!= current
->fsuid
&&
1359 (sbi
->s_resgid
== 0 || !in_group_p (sbi
->s_resgid
))) {
1366 * ext4_should_retry_alloc()
1368 * @retries number of attemps has been made
1370 * ext4_should_retry_alloc() is called when ENOSPC is returned, and if
1371 * it is profitable to retry the operation, this function will wait
1372 * for the current or commiting transaction to complete, and then
1375 * if the total number of retries exceed three times, return FALSE.
1377 int ext4_should_retry_alloc(struct super_block
*sb
, int *retries
)
1379 if (!ext4_has_free_blocks(EXT4_SB(sb
)) || (*retries
)++ > 3)
1382 jbd_debug(1, "%s: retrying operation after ENOSPC\n", sb
->s_id
);
1384 return jbd2_journal_force_commit_nested(EXT4_SB(sb
)->s_journal
);
1388 * ext4_new_blocks() -- core block(s) allocation function
1389 * @handle: handle to this transaction
1390 * @inode: file inode
1391 * @goal: given target block(filesystem wide)
1392 * @count: target number of blocks to allocate
1395 * ext4_new_blocks uses a goal block to assist allocation. It tries to
1396 * allocate block(s) from the block group contains the goal block first. If that
1397 * fails, it will try to allocate block(s) from other block groups without
1398 * any specific goal block.
1401 ext4_fsblk_t
ext4_new_blocks(handle_t
*handle
, struct inode
*inode
,
1402 ext4_fsblk_t goal
, unsigned long *count
, int *errp
)
1404 struct buffer_head
*bitmap_bh
= NULL
;
1405 struct buffer_head
*gdp_bh
;
1406 unsigned long group_no
;
1408 ext4_grpblk_t grp_target_blk
; /* blockgroup relative goal block */
1409 ext4_grpblk_t grp_alloc_blk
; /* blockgroup-relative allocated block*/
1410 ext4_fsblk_t ret_block
; /* filesyetem-wide allocated block */
1411 int bgi
; /* blockgroup iteration index */
1413 int performed_allocation
= 0;
1414 ext4_grpblk_t free_blocks
; /* number of free blocks in a group */
1415 struct super_block
*sb
;
1416 struct ext4_group_desc
*gdp
;
1417 struct ext4_super_block
*es
;
1418 struct ext4_sb_info
*sbi
;
1419 struct ext4_reserve_window_node
*my_rsv
= NULL
;
1420 struct ext4_block_alloc_info
*block_i
;
1421 unsigned short windowsz
= 0;
1423 static int goal_hits
, goal_attempts
;
1425 unsigned long ngroups
;
1426 unsigned long num
= *count
;
1431 printk("ext4_new_block: nonexistent device");
1436 * Check quota for allocation of this block.
1438 if (DQUOT_ALLOC_BLOCK(inode
, num
)) {
1444 es
= EXT4_SB(sb
)->s_es
;
1445 ext4_debug("goal=%lu.\n", goal
);
1447 * Allocate a block from reservation only when
1448 * filesystem is mounted with reservation(default,-o reservation), and
1449 * it's a regular file, and
1450 * the desired window size is greater than 0 (One could use ioctl
1451 * command EXT4_IOC_SETRSVSZ to set the window size to 0 to turn off
1452 * reservation on that particular file)
1454 block_i
= EXT4_I(inode
)->i_block_alloc_info
;
1455 if (block_i
&& ((windowsz
= block_i
->rsv_window_node
.rsv_goal_size
) > 0))
1456 my_rsv
= &block_i
->rsv_window_node
;
1458 if (!ext4_has_free_blocks(sbi
)) {
1464 * First, test whether the goal block is free.
1466 if (goal
< le32_to_cpu(es
->s_first_data_block
) ||
1467 goal
>= ext4_blocks_count(es
))
1468 goal
= le32_to_cpu(es
->s_first_data_block
);
1469 ext4_get_group_no_and_offset(sb
, goal
, &group_no
, &grp_target_blk
);
1470 goal_group
= group_no
;
1472 gdp
= ext4_get_group_desc(sb
, group_no
, &gdp_bh
);
1476 free_blocks
= le16_to_cpu(gdp
->bg_free_blocks_count
);
1478 * if there is not enough free blocks to make a new resevation
1479 * turn off reservation for this allocation
1481 if (my_rsv
&& (free_blocks
< windowsz
)
1482 && (rsv_is_empty(&my_rsv
->rsv_window
)))
1485 if (free_blocks
> 0) {
1486 bitmap_bh
= read_block_bitmap(sb
, group_no
);
1489 grp_alloc_blk
= ext4_try_to_allocate_with_rsv(sb
, handle
,
1490 group_no
, bitmap_bh
, grp_target_blk
,
1491 my_rsv
, &num
, &fatal
);
1494 if (grp_alloc_blk
>= 0)
1498 ngroups
= EXT4_SB(sb
)->s_groups_count
;
1502 * Now search the rest of the groups. We assume that
1503 * i and gdp correctly point to the last group visited.
1505 for (bgi
= 0; bgi
< ngroups
; bgi
++) {
1507 if (group_no
>= ngroups
)
1509 gdp
= ext4_get_group_desc(sb
, group_no
, &gdp_bh
);
1514 free_blocks
= le16_to_cpu(gdp
->bg_free_blocks_count
);
1516 * skip this group if the number of
1517 * free blocks is less than half of the reservation
1520 if (free_blocks
<= (windowsz
/2))
1524 bitmap_bh
= read_block_bitmap(sb
, group_no
);
1528 * try to allocate block(s) from this group, without a goal(-1).
1530 grp_alloc_blk
= ext4_try_to_allocate_with_rsv(sb
, handle
,
1531 group_no
, bitmap_bh
, -1, my_rsv
,
1535 if (grp_alloc_blk
>= 0)
1539 * We may end up a bogus ealier ENOSPC error due to
1540 * filesystem is "full" of reservations, but
1541 * there maybe indeed free blocks avaliable on disk
1542 * In this case, we just forget about the reservations
1543 * just do block allocation as without reservations.
1547 group_no
= goal_group
;
1550 /* No space left on the device */
1556 ext4_debug("using block group %d(%d)\n",
1557 group_no
, gdp
->bg_free_blocks_count
);
1559 BUFFER_TRACE(gdp_bh
, "get_write_access");
1560 fatal
= ext4_journal_get_write_access(handle
, gdp_bh
);
1564 ret_block
= grp_alloc_blk
+ ext4_group_first_block_no(sb
, group_no
);
1566 if (in_range(ext4_block_bitmap(sb
, gdp
), ret_block
, num
) ||
1567 in_range(ext4_block_bitmap(sb
, gdp
), ret_block
, num
) ||
1568 in_range(ret_block
, ext4_inode_table(sb
, gdp
),
1569 EXT4_SB(sb
)->s_itb_per_group
) ||
1570 in_range(ret_block
+ num
- 1, ext4_inode_table(sb
, gdp
),
1571 EXT4_SB(sb
)->s_itb_per_group
))
1572 ext4_error(sb
, "ext4_new_block",
1573 "Allocating block in system zone - "
1574 "blocks from %llu, length %lu",
1577 performed_allocation
= 1;
1579 #ifdef CONFIG_JBD_DEBUG
1581 struct buffer_head
*debug_bh
;
1583 /* Record bitmap buffer state in the newly allocated block */
1584 debug_bh
= sb_find_get_block(sb
, ret_block
);
1586 BUFFER_TRACE(debug_bh
, "state when allocated");
1587 BUFFER_TRACE2(debug_bh
, bitmap_bh
, "bitmap state");
1591 jbd_lock_bh_state(bitmap_bh
);
1592 spin_lock(sb_bgl_lock(sbi
, group_no
));
1593 if (buffer_jbd(bitmap_bh
) && bh2jh(bitmap_bh
)->b_committed_data
) {
1596 for (i
= 0; i
< num
; i
++) {
1597 if (ext4_test_bit(grp_alloc_blk
+i
,
1598 bh2jh(bitmap_bh
)->b_committed_data
)) {
1599 printk("%s: block was unexpectedly set in "
1600 "b_committed_data\n", __FUNCTION__
);
1604 ext4_debug("found bit %d\n", grp_alloc_blk
);
1605 spin_unlock(sb_bgl_lock(sbi
, group_no
));
1606 jbd_unlock_bh_state(bitmap_bh
);
1609 if (ret_block
+ num
- 1 >= ext4_blocks_count(es
)) {
1610 ext4_error(sb
, "ext4_new_block",
1611 "block(%llu) >= blocks count(%llu) - "
1612 "block_group = %lu, es == %p ", ret_block
,
1613 ext4_blocks_count(es
), group_no
, es
);
1618 * It is up to the caller to add the new buffer to a journal
1619 * list of some description. We don't know in advance whether
1620 * the caller wants to use it as metadata or data.
1622 ext4_debug("allocating block %lu. Goal hits %d of %d.\n",
1623 ret_block
, goal_hits
, goal_attempts
);
1625 spin_lock(sb_bgl_lock(sbi
, group_no
));
1626 gdp
->bg_free_blocks_count
=
1627 cpu_to_le16(le16_to_cpu(gdp
->bg_free_blocks_count
)-num
);
1628 spin_unlock(sb_bgl_lock(sbi
, group_no
));
1629 percpu_counter_mod(&sbi
->s_freeblocks_counter
, -num
);
1631 BUFFER_TRACE(gdp_bh
, "journal_dirty_metadata for group descriptor");
1632 err
= ext4_journal_dirty_metadata(handle
, gdp_bh
);
1642 DQUOT_FREE_BLOCK(inode
, *count
-num
);
1651 ext4_std_error(sb
, fatal
);
1654 * Undo the block allocation
1656 if (!performed_allocation
)
1657 DQUOT_FREE_BLOCK(inode
, *count
);
1662 ext4_fsblk_t
ext4_new_block(handle_t
*handle
, struct inode
*inode
,
1663 ext4_fsblk_t goal
, int *errp
)
1665 unsigned long count
= 1;
1667 return ext4_new_blocks(handle
, inode
, goal
, &count
, errp
);
1671 * ext4_count_free_blocks() -- count filesystem free blocks
1674 * Adds up the number of free blocks from each block group.
1676 ext4_fsblk_t
ext4_count_free_blocks(struct super_block
*sb
)
1678 ext4_fsblk_t desc_count
;
1679 struct ext4_group_desc
*gdp
;
1681 unsigned long ngroups
= EXT4_SB(sb
)->s_groups_count
;
1683 struct ext4_super_block
*es
;
1684 ext4_fsblk_t bitmap_count
;
1686 struct buffer_head
*bitmap_bh
= NULL
;
1688 es
= EXT4_SB(sb
)->s_es
;
1694 for (i
= 0; i
< ngroups
; i
++) {
1695 gdp
= ext4_get_group_desc(sb
, i
, NULL
);
1698 desc_count
+= le16_to_cpu(gdp
->bg_free_blocks_count
);
1700 bitmap_bh
= read_block_bitmap(sb
, i
);
1701 if (bitmap_bh
== NULL
)
1704 x
= ext4_count_free(bitmap_bh
, sb
->s_blocksize
);
1705 printk("group %d: stored = %d, counted = %lu\n",
1706 i
, le16_to_cpu(gdp
->bg_free_blocks_count
), x
);
1710 printk("ext4_count_free_blocks: stored = %llu"
1711 ", computed = %llu, %llu\n",
1712 EXT4_FREE_BLOCKS_COUNT(es
),
1713 desc_count
, bitmap_count
);
1714 return bitmap_count
;
1718 for (i
= 0; i
< ngroups
; i
++) {
1719 gdp
= ext4_get_group_desc(sb
, i
, NULL
);
1722 desc_count
+= le16_to_cpu(gdp
->bg_free_blocks_count
);
1730 block_in_use(ext4_fsblk_t block
, struct super_block
*sb
, unsigned char *map
)
1732 ext4_grpblk_t offset
;
1734 ext4_get_group_no_and_offset(sb
, block
, NULL
, &offset
);
1735 return ext4_test_bit (offset
, map
);
1738 static inline int test_root(int a
, int b
)
1747 static int ext4_group_sparse(int group
)
1753 return (test_root(group
, 7) || test_root(group
, 5) ||
1754 test_root(group
, 3));
1758 * ext4_bg_has_super - number of blocks used by the superblock in group
1759 * @sb: superblock for filesystem
1760 * @group: group number to check
1762 * Return the number of blocks used by the superblock (primary or backup)
1763 * in this group. Currently this will be only 0 or 1.
1765 int ext4_bg_has_super(struct super_block
*sb
, int group
)
1767 if (EXT4_HAS_RO_COMPAT_FEATURE(sb
,
1768 EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER
) &&
1769 !ext4_group_sparse(group
))
1774 static unsigned long ext4_bg_num_gdb_meta(struct super_block
*sb
, int group
)
1776 unsigned long metagroup
= group
/ EXT4_DESC_PER_BLOCK(sb
);
1777 unsigned long first
= metagroup
* EXT4_DESC_PER_BLOCK(sb
);
1778 unsigned long last
= first
+ EXT4_DESC_PER_BLOCK(sb
) - 1;
1780 if (group
== first
|| group
== first
+ 1 || group
== last
)
1785 static unsigned long ext4_bg_num_gdb_nometa(struct super_block
*sb
, int group
)
1787 if (EXT4_HAS_RO_COMPAT_FEATURE(sb
,
1788 EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER
) &&
1789 !ext4_group_sparse(group
))
1791 return EXT4_SB(sb
)->s_gdb_count
;
1795 * ext4_bg_num_gdb - number of blocks used by the group table in group
1796 * @sb: superblock for filesystem
1797 * @group: group number to check
1799 * Return the number of blocks used by the group descriptor table
1800 * (primary or backup) in this group. In the future there may be a
1801 * different number of descriptor blocks in each group.
1803 unsigned long ext4_bg_num_gdb(struct super_block
*sb
, int group
)
1805 unsigned long first_meta_bg
=
1806 le32_to_cpu(EXT4_SB(sb
)->s_es
->s_first_meta_bg
);
1807 unsigned long metagroup
= group
/ EXT4_DESC_PER_BLOCK(sb
);
1809 if (!EXT4_HAS_INCOMPAT_FEATURE(sb
,EXT4_FEATURE_INCOMPAT_META_BG
) ||
1810 metagroup
< first_meta_bg
)
1811 return ext4_bg_num_gdb_nometa(sb
,group
);
1813 return ext4_bg_num_gdb_meta(sb
,group
);