2 * Copyright (c) 2003-2006, Cluster File Systems, Inc, info@clusterfs.com
3 * Written by Alex Tomas <alex@clusterfs.com>
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
14 * You should have received a copy of the GNU General Public Licens
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-
21 * mballoc.c contains the multiblocks allocation routines
25 #include <linux/debugfs.h>
26 #include <linux/slab.h>
27 #include <trace/events/ext4.h>
31 * - test ext4_ext_search_left() and ext4_ext_search_right()
32 * - search for metadata in few groups
35 * - normalization should take into account whether file is still open
36 * - discard preallocations if no free space left (policy?)
37 * - don't normalize tails
39 * - reservation for superuser
42 * - bitmap read-ahead (proposed by Oleg Drokin aka green)
43 * - track min/max extents in each group for better group selection
44 * - mb_mark_used() may allocate chunk right after splitting buddy
45 * - tree of groups sorted by number of free blocks
50 * The allocation request involve request for multiple number of blocks
51 * near to the goal(block) value specified.
53 * During initialization phase of the allocator we decide to use the
54 * group preallocation or inode preallocation depending on the size of
55 * the file. The size of the file could be the resulting file size we
56 * would have after allocation, or the current file size, which ever
57 * is larger. If the size is less than sbi->s_mb_stream_request we
58 * select to use the group preallocation. The default value of
59 * s_mb_stream_request is 16 blocks. This can also be tuned via
60 * /sys/fs/ext4/<partition>/mb_stream_req. The value is represented in
61 * terms of number of blocks.
63 * The main motivation for having small file use group preallocation is to
64 * ensure that we have small files closer together on the disk.
66 * First stage the allocator looks at the inode prealloc list,
67 * ext4_inode_info->i_prealloc_list, which contains list of prealloc
68 * spaces for this particular inode. The inode prealloc space is
71 * pa_lstart -> the logical start block for this prealloc space
72 * pa_pstart -> the physical start block for this prealloc space
73 * pa_len -> length for this prealloc space
74 * pa_free -> free space available in this prealloc space
76 * The inode preallocation space is used looking at the _logical_ start
77 * block. If only the logical file block falls within the range of prealloc
78 * space we will consume the particular prealloc space. This make sure that
79 * that the we have contiguous physical blocks representing the file blocks
81 * The important thing to be noted in case of inode prealloc space is that
82 * we don't modify the values associated to inode prealloc space except
85 * If we are not able to find blocks in the inode prealloc space and if we
86 * have the group allocation flag set then we look at the locality group
87 * prealloc space. These are per CPU prealloc list repreasented as
89 * ext4_sb_info.s_locality_groups[smp_processor_id()]
91 * The reason for having a per cpu locality group is to reduce the contention
92 * between CPUs. It is possible to get scheduled at this point.
94 * The locality group prealloc space is used looking at whether we have
95 * enough free space (pa_free) withing the prealloc space.
97 * If we can't allocate blocks via inode prealloc or/and locality group
98 * prealloc then we look at the buddy cache. The buddy cache is represented
99 * by ext4_sb_info.s_buddy_cache (struct inode) whose file offset gets
100 * mapped to the buddy and bitmap information regarding different
101 * groups. The buddy information is attached to buddy cache inode so that
102 * we can access them through the page cache. The information regarding
103 * each group is loaded via ext4_mb_load_buddy. The information involve
104 * block bitmap and buddy information. The information are stored in the
108 * [ group 0 bitmap][ group 0 buddy] [group 1][ group 1]...
111 * one block each for bitmap and buddy information. So for each group we
112 * take up 2 blocks. A page can contain blocks_per_page (PAGE_CACHE_SIZE /
113 * blocksize) blocks. So it can have information regarding groups_per_page
114 * which is blocks_per_page/2
116 * The buddy cache inode is not stored on disk. The inode is thrown
117 * away when the filesystem is unmounted.
119 * We look for count number of blocks in the buddy cache. If we were able
120 * to locate that many free blocks we return with additional information
121 * regarding rest of the contiguous physical block available
123 * Before allocating blocks via buddy cache we normalize the request
124 * blocks. This ensure we ask for more blocks that we needed. The extra
125 * blocks that we get after allocation is added to the respective prealloc
126 * list. In case of inode preallocation we follow a list of heuristics
127 * based on file size. This can be found in ext4_mb_normalize_request. If
128 * we are doing a group prealloc we try to normalize the request to
129 * sbi->s_mb_group_prealloc. Default value of s_mb_group_prealloc is
130 * 512 blocks. This can be tuned via
131 * /sys/fs/ext4/<partition/mb_group_prealloc. The value is represented in
132 * terms of number of blocks. If we have mounted the file system with -O
133 * stripe=<value> option the group prealloc request is normalized to the
134 * stripe value (sbi->s_stripe)
136 * The regular allocator(using the buddy cache) supports few tunables.
138 * /sys/fs/ext4/<partition>/mb_min_to_scan
139 * /sys/fs/ext4/<partition>/mb_max_to_scan
140 * /sys/fs/ext4/<partition>/mb_order2_req
142 * The regular allocator uses buddy scan only if the request len is power of
143 * 2 blocks and the order of allocation is >= sbi->s_mb_order2_reqs. The
144 * value of s_mb_order2_reqs can be tuned via
145 * /sys/fs/ext4/<partition>/mb_order2_req. If the request len is equal to
146 * stripe size (sbi->s_stripe), we try to search for contiguous block in
147 * stripe size. This should result in better allocation on RAID setups. If
148 * not, we search in the specific group using bitmap for best extents. The
149 * tunable min_to_scan and max_to_scan control the behaviour here.
150 * min_to_scan indicate how long the mballoc __must__ look for a best
151 * extent and max_to_scan indicates how long the mballoc __can__ look for a
152 * best extent in the found extents. Searching for the blocks starts with
153 * the group specified as the goal value in allocation context via
154 * ac_g_ex. Each group is first checked based on the criteria whether it
155 * can used for allocation. ext4_mb_good_group explains how the groups are
158 * Both the prealloc space are getting populated as above. So for the first
159 * request we will hit the buddy cache which will result in this prealloc
160 * space getting filled. The prealloc space is then later used for the
161 * subsequent request.
165 * mballoc operates on the following data:
167 * - in-core buddy (actually includes buddy and bitmap)
168 * - preallocation descriptors (PAs)
170 * there are two types of preallocations:
172 * assiged to specific inode and can be used for this inode only.
173 * it describes part of inode's space preallocated to specific
174 * physical blocks. any block from that preallocated can be used
175 * independent. the descriptor just tracks number of blocks left
176 * unused. so, before taking some block from descriptor, one must
177 * make sure corresponded logical block isn't allocated yet. this
178 * also means that freeing any block within descriptor's range
179 * must discard all preallocated blocks.
181 * assigned to specific locality group which does not translate to
182 * permanent set of inodes: inode can join and leave group. space
183 * from this type of preallocation can be used for any inode. thus
184 * it's consumed from the beginning to the end.
186 * relation between them can be expressed as:
187 * in-core buddy = on-disk bitmap + preallocation descriptors
189 * this mean blocks mballoc considers used are:
190 * - allocated blocks (persistent)
191 * - preallocated blocks (non-persistent)
193 * consistency in mballoc world means that at any time a block is either
194 * free or used in ALL structures. notice: "any time" should not be read
195 * literally -- time is discrete and delimited by locks.
197 * to keep it simple, we don't use block numbers, instead we count number of
198 * blocks: how many blocks marked used/free in on-disk bitmap, buddy and PA.
200 * all operations can be expressed as:
201 * - init buddy: buddy = on-disk + PAs
202 * - new PA: buddy += N; PA = N
203 * - use inode PA: on-disk += N; PA -= N
204 * - discard inode PA buddy -= on-disk - PA; PA = 0
205 * - use locality group PA on-disk += N; PA -= N
206 * - discard locality group PA buddy -= PA; PA = 0
207 * note: 'buddy -= on-disk - PA' is used to show that on-disk bitmap
208 * is used in real operation because we can't know actual used
209 * bits from PA, only from on-disk bitmap
211 * if we follow this strict logic, then all operations above should be atomic.
212 * given some of them can block, we'd have to use something like semaphores
213 * killing performance on high-end SMP hardware. let's try to relax it using
214 * the following knowledge:
215 * 1) if buddy is referenced, it's already initialized
216 * 2) while block is used in buddy and the buddy is referenced,
217 * nobody can re-allocate that block
218 * 3) we work on bitmaps and '+' actually means 'set bits'. if on-disk has
219 * bit set and PA claims same block, it's OK. IOW, one can set bit in
220 * on-disk bitmap if buddy has same bit set or/and PA covers corresponded
223 * so, now we're building a concurrency table:
226 * blocks for PA are allocated in the buddy, buddy must be referenced
227 * until PA is linked to allocation group to avoid concurrent buddy init
229 * we need to make sure that either on-disk bitmap or PA has uptodate data
230 * given (3) we care that PA-=N operation doesn't interfere with init
232 * the simplest way would be to have buddy initialized by the discard
233 * - use locality group PA
234 * again PA-=N must be serialized with init
235 * - discard locality group PA
236 * the simplest way would be to have buddy initialized by the discard
239 * i_data_sem serializes them
241 * discard process must wait until PA isn't used by another process
242 * - use locality group PA
243 * some mutex should serialize them
244 * - discard locality group PA
245 * discard process must wait until PA isn't used by another process
248 * i_data_sem or another mutex should serializes them
250 * discard process must wait until PA isn't used by another process
251 * - use locality group PA
252 * nothing wrong here -- they're different PAs covering different blocks
253 * - discard locality group PA
254 * discard process must wait until PA isn't used by another process
256 * now we're ready to make few consequences:
257 * - PA is referenced and while it is no discard is possible
258 * - PA is referenced until block isn't marked in on-disk bitmap
259 * - PA changes only after on-disk bitmap
260 * - discard must not compete with init. either init is done before
261 * any discard or they're serialized somehow
262 * - buddy init as sum of on-disk bitmap and PAs is done atomically
264 * a special case when we've used PA to emptiness. no need to modify buddy
265 * in this case, but we should care about concurrent init
270 * Logic in few words:
275 * mark bits in on-disk bitmap
278 * - use preallocation:
279 * find proper PA (per-inode or group)
281 * mark bits in on-disk bitmap
287 * mark bits in on-disk bitmap
290 * - discard preallocations in group:
292 * move them onto local list
293 * load on-disk bitmap
295 * remove PA from object (inode or locality group)
296 * mark free blocks in-core
298 * - discard inode's preallocations:
305 * - bitlock on a group (group)
306 * - object (inode/locality) (object)
317 * - release consumed pa:
322 * - generate in-core bitmap:
326 * - discard all for given object (inode, locality group):
331 * - discard all for given group:
338 static struct kmem_cache
*ext4_pspace_cachep
;
339 static struct kmem_cache
*ext4_ac_cachep
;
340 static struct kmem_cache
*ext4_free_ext_cachep
;
341 static void ext4_mb_generate_from_pa(struct super_block
*sb
, void *bitmap
,
343 static void ext4_mb_generate_from_freelist(struct super_block
*sb
, void *bitmap
,
345 static void release_blocks_on_commit(journal_t
*journal
, transaction_t
*txn
);
347 static inline void *mb_correct_addr_and_bit(int *bit
, void *addr
)
349 #if BITS_PER_LONG == 64
350 *bit
+= ((unsigned long) addr
& 7UL) << 3;
351 addr
= (void *) ((unsigned long) addr
& ~7UL);
352 #elif BITS_PER_LONG == 32
353 *bit
+= ((unsigned long) addr
& 3UL) << 3;
354 addr
= (void *) ((unsigned long) addr
& ~3UL);
356 #error "how many bits you are?!"
361 static inline int mb_test_bit(int bit
, void *addr
)
364 * ext4_test_bit on architecture like powerpc
365 * needs unsigned long aligned address
367 addr
= mb_correct_addr_and_bit(&bit
, addr
);
368 return ext4_test_bit(bit
, addr
);
371 static inline void mb_set_bit(int bit
, void *addr
)
373 addr
= mb_correct_addr_and_bit(&bit
, addr
);
374 ext4_set_bit(bit
, addr
);
377 static inline void mb_clear_bit(int bit
, void *addr
)
379 addr
= mb_correct_addr_and_bit(&bit
, addr
);
380 ext4_clear_bit(bit
, addr
);
383 static inline int mb_find_next_zero_bit(void *addr
, int max
, int start
)
385 int fix
= 0, ret
, tmpmax
;
386 addr
= mb_correct_addr_and_bit(&fix
, addr
);
390 ret
= ext4_find_next_zero_bit(addr
, tmpmax
, start
) - fix
;
396 static inline int mb_find_next_bit(void *addr
, int max
, int start
)
398 int fix
= 0, ret
, tmpmax
;
399 addr
= mb_correct_addr_and_bit(&fix
, addr
);
403 ret
= ext4_find_next_bit(addr
, tmpmax
, start
) - fix
;
409 static void *mb_find_buddy(struct ext4_buddy
*e4b
, int order
, int *max
)
413 BUG_ON(EXT4_MB_BITMAP(e4b
) == EXT4_MB_BUDDY(e4b
));
416 if (order
> e4b
->bd_blkbits
+ 1) {
421 /* at order 0 we see each particular block */
422 *max
= 1 << (e4b
->bd_blkbits
+ 3);
424 return EXT4_MB_BITMAP(e4b
);
426 bb
= EXT4_MB_BUDDY(e4b
) + EXT4_SB(e4b
->bd_sb
)->s_mb_offsets
[order
];
427 *max
= EXT4_SB(e4b
->bd_sb
)->s_mb_maxs
[order
];
433 static void mb_free_blocks_double(struct inode
*inode
, struct ext4_buddy
*e4b
,
434 int first
, int count
)
437 struct super_block
*sb
= e4b
->bd_sb
;
439 if (unlikely(e4b
->bd_info
->bb_bitmap
== NULL
))
441 assert_spin_locked(ext4_group_lock_ptr(sb
, e4b
->bd_group
));
442 for (i
= 0; i
< count
; i
++) {
443 if (!mb_test_bit(first
+ i
, e4b
->bd_info
->bb_bitmap
)) {
444 ext4_fsblk_t blocknr
;
446 blocknr
= ext4_group_first_block_no(sb
, e4b
->bd_group
);
447 blocknr
+= first
+ i
;
448 ext4_grp_locked_error(sb
, e4b
->bd_group
,
449 inode
? inode
->i_ino
: 0,
451 "freeing block already freed "
455 mb_clear_bit(first
+ i
, e4b
->bd_info
->bb_bitmap
);
459 static void mb_mark_used_double(struct ext4_buddy
*e4b
, int first
, int count
)
463 if (unlikely(e4b
->bd_info
->bb_bitmap
== NULL
))
465 assert_spin_locked(ext4_group_lock_ptr(e4b
->bd_sb
, e4b
->bd_group
));
466 for (i
= 0; i
< count
; i
++) {
467 BUG_ON(mb_test_bit(first
+ i
, e4b
->bd_info
->bb_bitmap
));
468 mb_set_bit(first
+ i
, e4b
->bd_info
->bb_bitmap
);
472 static void mb_cmp_bitmaps(struct ext4_buddy
*e4b
, void *bitmap
)
474 if (memcmp(e4b
->bd_info
->bb_bitmap
, bitmap
, e4b
->bd_sb
->s_blocksize
)) {
475 unsigned char *b1
, *b2
;
477 b1
= (unsigned char *) e4b
->bd_info
->bb_bitmap
;
478 b2
= (unsigned char *) bitmap
;
479 for (i
= 0; i
< e4b
->bd_sb
->s_blocksize
; i
++) {
480 if (b1
[i
] != b2
[i
]) {
481 printk(KERN_ERR
"corruption in group %u "
482 "at byte %u(%u): %x in copy != %x "
483 "on disk/prealloc\n",
484 e4b
->bd_group
, i
, i
* 8, b1
[i
], b2
[i
]);
492 static inline void mb_free_blocks_double(struct inode
*inode
,
493 struct ext4_buddy
*e4b
, int first
, int count
)
497 static inline void mb_mark_used_double(struct ext4_buddy
*e4b
,
498 int first
, int count
)
502 static inline void mb_cmp_bitmaps(struct ext4_buddy
*e4b
, void *bitmap
)
508 #ifdef AGGRESSIVE_CHECK
510 #define MB_CHECK_ASSERT(assert) \
514 "Assertion failure in %s() at %s:%d: \"%s\"\n", \
515 function, file, line, # assert); \
520 static int __mb_check_buddy(struct ext4_buddy
*e4b
, char *file
,
521 const char *function
, int line
)
523 struct super_block
*sb
= e4b
->bd_sb
;
524 int order
= e4b
->bd_blkbits
+ 1;
531 struct ext4_group_info
*grp
;
534 struct list_head
*cur
;
539 static int mb_check_counter
;
540 if (mb_check_counter
++ % 100 != 0)
545 buddy
= mb_find_buddy(e4b
, order
, &max
);
546 MB_CHECK_ASSERT(buddy
);
547 buddy2
= mb_find_buddy(e4b
, order
- 1, &max2
);
548 MB_CHECK_ASSERT(buddy2
);
549 MB_CHECK_ASSERT(buddy
!= buddy2
);
550 MB_CHECK_ASSERT(max
* 2 == max2
);
553 for (i
= 0; i
< max
; i
++) {
555 if (mb_test_bit(i
, buddy
)) {
556 /* only single bit in buddy2 may be 1 */
557 if (!mb_test_bit(i
<< 1, buddy2
)) {
559 mb_test_bit((i
<<1)+1, buddy2
));
560 } else if (!mb_test_bit((i
<< 1) + 1, buddy2
)) {
562 mb_test_bit(i
<< 1, buddy2
));
567 /* both bits in buddy2 must be 0 */
568 MB_CHECK_ASSERT(mb_test_bit(i
<< 1, buddy2
));
569 MB_CHECK_ASSERT(mb_test_bit((i
<< 1) + 1, buddy2
));
571 for (j
= 0; j
< (1 << order
); j
++) {
572 k
= (i
* (1 << order
)) + j
;
574 !mb_test_bit(k
, EXT4_MB_BITMAP(e4b
)));
578 MB_CHECK_ASSERT(e4b
->bd_info
->bb_counters
[order
] == count
);
583 buddy
= mb_find_buddy(e4b
, 0, &max
);
584 for (i
= 0; i
< max
; i
++) {
585 if (!mb_test_bit(i
, buddy
)) {
586 MB_CHECK_ASSERT(i
>= e4b
->bd_info
->bb_first_free
);
594 /* check used bits only */
595 for (j
= 0; j
< e4b
->bd_blkbits
+ 1; j
++) {
596 buddy2
= mb_find_buddy(e4b
, j
, &max2
);
598 MB_CHECK_ASSERT(k
< max2
);
599 MB_CHECK_ASSERT(mb_test_bit(k
, buddy2
));
602 MB_CHECK_ASSERT(!EXT4_MB_GRP_NEED_INIT(e4b
->bd_info
));
603 MB_CHECK_ASSERT(e4b
->bd_info
->bb_fragments
== fragments
);
605 grp
= ext4_get_group_info(sb
, e4b
->bd_group
);
606 buddy
= mb_find_buddy(e4b
, 0, &max
);
607 list_for_each(cur
, &grp
->bb_prealloc_list
) {
608 ext4_group_t groupnr
;
609 struct ext4_prealloc_space
*pa
;
610 pa
= list_entry(cur
, struct ext4_prealloc_space
, pa_group_list
);
611 ext4_get_group_no_and_offset(sb
, pa
->pa_pstart
, &groupnr
, &k
);
612 MB_CHECK_ASSERT(groupnr
== e4b
->bd_group
);
613 for (i
= 0; i
< pa
->pa_len
; i
++)
614 MB_CHECK_ASSERT(mb_test_bit(k
+ i
, buddy
));
618 #undef MB_CHECK_ASSERT
619 #define mb_check_buddy(e4b) __mb_check_buddy(e4b, \
620 __FILE__, __func__, __LINE__)
622 #define mb_check_buddy(e4b)
625 /* FIXME!! need more doc */
626 static void ext4_mb_mark_free_simple(struct super_block
*sb
,
627 void *buddy
, ext4_grpblk_t first
, ext4_grpblk_t len
,
628 struct ext4_group_info
*grp
)
630 struct ext4_sb_info
*sbi
= EXT4_SB(sb
);
634 unsigned short border
;
636 BUG_ON(len
> EXT4_BLOCKS_PER_GROUP(sb
));
638 border
= 2 << sb
->s_blocksize_bits
;
641 /* find how many blocks can be covered since this position */
642 max
= ffs(first
| border
) - 1;
644 /* find how many blocks of power 2 we need to mark */
651 /* mark multiblock chunks only */
652 grp
->bb_counters
[min
]++;
654 mb_clear_bit(first
>> min
,
655 buddy
+ sbi
->s_mb_offsets
[min
]);
663 * Cache the order of the largest free extent we have available in this block
667 mb_set_largest_free_order(struct super_block
*sb
, struct ext4_group_info
*grp
)
672 grp
->bb_largest_free_order
= -1; /* uninit */
674 bits
= sb
->s_blocksize_bits
+ 1;
675 for (i
= bits
; i
>= 0; i
--) {
676 if (grp
->bb_counters
[i
] > 0) {
677 grp
->bb_largest_free_order
= i
;
683 static noinline_for_stack
684 void ext4_mb_generate_buddy(struct super_block
*sb
,
685 void *buddy
, void *bitmap
, ext4_group_t group
)
687 struct ext4_group_info
*grp
= ext4_get_group_info(sb
, group
);
688 ext4_grpblk_t max
= EXT4_BLOCKS_PER_GROUP(sb
);
693 unsigned fragments
= 0;
694 unsigned long long period
= get_cycles();
696 /* initialize buddy from bitmap which is aggregation
697 * of on-disk bitmap and preallocations */
698 i
= mb_find_next_zero_bit(bitmap
, max
, 0);
699 grp
->bb_first_free
= i
;
703 i
= mb_find_next_bit(bitmap
, max
, i
);
707 ext4_mb_mark_free_simple(sb
, buddy
, first
, len
, grp
);
709 grp
->bb_counters
[0]++;
711 i
= mb_find_next_zero_bit(bitmap
, max
, i
);
713 grp
->bb_fragments
= fragments
;
715 if (free
!= grp
->bb_free
) {
716 ext4_grp_locked_error(sb
, group
, 0, 0,
717 "%u blocks in bitmap, %u in gd",
720 * If we intent to continue, we consider group descritor
721 * corrupt and update bb_free using bitmap value
725 mb_set_largest_free_order(sb
, grp
);
727 clear_bit(EXT4_GROUP_INFO_NEED_INIT_BIT
, &(grp
->bb_state
));
729 period
= get_cycles() - period
;
730 spin_lock(&EXT4_SB(sb
)->s_bal_lock
);
731 EXT4_SB(sb
)->s_mb_buddies_generated
++;
732 EXT4_SB(sb
)->s_mb_generation_time
+= period
;
733 spin_unlock(&EXT4_SB(sb
)->s_bal_lock
);
736 /* The buddy information is attached the buddy cache inode
737 * for convenience. The information regarding each group
738 * is loaded via ext4_mb_load_buddy. The information involve
739 * block bitmap and buddy information. The information are
740 * stored in the inode as
743 * [ group 0 bitmap][ group 0 buddy] [group 1][ group 1]...
746 * one block each for bitmap and buddy information.
747 * So for each group we take up 2 blocks. A page can
748 * contain blocks_per_page (PAGE_CACHE_SIZE / blocksize) blocks.
749 * So it can have information regarding groups_per_page which
750 * is blocks_per_page/2
752 * Locking note: This routine takes the block group lock of all groups
753 * for this page; do not hold this lock when calling this routine!
756 static int ext4_mb_init_cache(struct page
*page
, char *incore
)
758 ext4_group_t ngroups
;
764 ext4_group_t first_group
;
766 struct super_block
*sb
;
767 struct buffer_head
*bhs
;
768 struct buffer_head
**bh
;
773 mb_debug(1, "init page %lu\n", page
->index
);
775 inode
= page
->mapping
->host
;
777 ngroups
= ext4_get_groups_count(sb
);
778 blocksize
= 1 << inode
->i_blkbits
;
779 blocks_per_page
= PAGE_CACHE_SIZE
/ blocksize
;
781 groups_per_page
= blocks_per_page
>> 1;
782 if (groups_per_page
== 0)
785 /* allocate buffer_heads to read bitmaps */
786 if (groups_per_page
> 1) {
788 i
= sizeof(struct buffer_head
*) * groups_per_page
;
789 bh
= kzalloc(i
, GFP_NOFS
);
795 first_group
= page
->index
* blocks_per_page
/ 2;
797 /* read all groups the page covers into the cache */
798 for (i
= 0; i
< groups_per_page
; i
++) {
799 struct ext4_group_desc
*desc
;
801 if (first_group
+ i
>= ngroups
)
805 desc
= ext4_get_group_desc(sb
, first_group
+ i
, NULL
);
810 bh
[i
] = sb_getblk(sb
, ext4_block_bitmap(sb
, desc
));
814 if (bitmap_uptodate(bh
[i
]))
818 if (bitmap_uptodate(bh
[i
])) {
819 unlock_buffer(bh
[i
]);
822 ext4_lock_group(sb
, first_group
+ i
);
823 if (desc
->bg_flags
& cpu_to_le16(EXT4_BG_BLOCK_UNINIT
)) {
824 ext4_init_block_bitmap(sb
, bh
[i
],
825 first_group
+ i
, desc
);
826 set_bitmap_uptodate(bh
[i
]);
827 set_buffer_uptodate(bh
[i
]);
828 ext4_unlock_group(sb
, first_group
+ i
);
829 unlock_buffer(bh
[i
]);
832 ext4_unlock_group(sb
, first_group
+ i
);
833 if (buffer_uptodate(bh
[i
])) {
835 * if not uninit if bh is uptodate,
836 * bitmap is also uptodate
838 set_bitmap_uptodate(bh
[i
]);
839 unlock_buffer(bh
[i
]);
844 * submit the buffer_head for read. We can
845 * safely mark the bitmap as uptodate now.
846 * We do it here so the bitmap uptodate bit
847 * get set with buffer lock held.
849 set_bitmap_uptodate(bh
[i
]);
850 bh
[i
]->b_end_io
= end_buffer_read_sync
;
851 submit_bh(READ
, bh
[i
]);
852 mb_debug(1, "read bitmap for group %u\n", first_group
+ i
);
855 /* wait for I/O completion */
856 for (i
= 0; i
< groups_per_page
&& bh
[i
]; i
++)
857 wait_on_buffer(bh
[i
]);
860 for (i
= 0; i
< groups_per_page
&& bh
[i
]; i
++)
861 if (!buffer_uptodate(bh
[i
]))
865 first_block
= page
->index
* blocks_per_page
;
867 memset(page_address(page
), 0xff, PAGE_CACHE_SIZE
);
868 for (i
= 0; i
< blocks_per_page
; i
++) {
870 struct ext4_group_info
*grinfo
;
872 group
= (first_block
+ i
) >> 1;
873 if (group
>= ngroups
)
877 * data carry information regarding this
878 * particular group in the format specified
882 data
= page_address(page
) + (i
* blocksize
);
883 bitmap
= bh
[group
- first_group
]->b_data
;
886 * We place the buddy block and bitmap block
889 if ((first_block
+ i
) & 1) {
890 /* this is block of buddy */
891 BUG_ON(incore
== NULL
);
892 mb_debug(1, "put buddy for group %u in page %lu/%x\n",
893 group
, page
->index
, i
* blocksize
);
894 trace_ext4_mb_buddy_bitmap_load(sb
, group
);
895 grinfo
= ext4_get_group_info(sb
, group
);
896 grinfo
->bb_fragments
= 0;
897 memset(grinfo
->bb_counters
, 0,
898 sizeof(*grinfo
->bb_counters
) *
899 (sb
->s_blocksize_bits
+2));
901 * incore got set to the group block bitmap below
903 ext4_lock_group(sb
, group
);
904 ext4_mb_generate_buddy(sb
, data
, incore
, group
);
905 ext4_unlock_group(sb
, group
);
908 /* this is block of bitmap */
909 BUG_ON(incore
!= NULL
);
910 mb_debug(1, "put bitmap for group %u in page %lu/%x\n",
911 group
, page
->index
, i
* blocksize
);
912 trace_ext4_mb_bitmap_load(sb
, group
);
914 /* see comments in ext4_mb_put_pa() */
915 ext4_lock_group(sb
, group
);
916 memcpy(data
, bitmap
, blocksize
);
918 /* mark all preallocated blks used in in-core bitmap */
919 ext4_mb_generate_from_pa(sb
, data
, group
);
920 ext4_mb_generate_from_freelist(sb
, data
, group
);
921 ext4_unlock_group(sb
, group
);
923 /* set incore so that the buddy information can be
924 * generated using this
929 SetPageUptodate(page
);
933 for (i
= 0; i
< groups_per_page
&& bh
[i
]; i
++)
942 * Locking note: This routine calls ext4_mb_init_cache(), which takes the
943 * block group lock of all groups for this page; do not hold the BG lock when
944 * calling this routine!
946 static noinline_for_stack
947 int ext4_mb_init_group(struct super_block
*sb
, ext4_group_t group
)
953 int block
, pnum
, poff
;
954 int num_grp_locked
= 0;
955 struct ext4_group_info
*this_grp
;
956 struct ext4_sb_info
*sbi
= EXT4_SB(sb
);
957 struct inode
*inode
= sbi
->s_buddy_cache
;
958 struct page
*page
= NULL
, *bitmap_page
= NULL
;
960 mb_debug(1, "init group %u\n", group
);
961 blocks_per_page
= PAGE_CACHE_SIZE
/ sb
->s_blocksize
;
962 this_grp
= ext4_get_group_info(sb
, group
);
964 * This ensures that we don't reinit the buddy cache
965 * page which map to the group from which we are already
966 * allocating. If we are looking at the buddy cache we would
967 * have taken a reference using ext4_mb_load_buddy and that
968 * would have taken the alloc_sem lock.
970 num_grp_locked
= ext4_mb_get_buddy_cache_lock(sb
, group
);
971 if (!EXT4_MB_GRP_NEED_INIT(this_grp
)) {
973 * somebody initialized the group
974 * return without doing anything
980 * the buddy cache inode stores the block bitmap
981 * and buddy information in consecutive blocks.
982 * So for each group we need two blocks.
985 pnum
= block
/ blocks_per_page
;
986 poff
= block
% blocks_per_page
;
987 page
= find_or_create_page(inode
->i_mapping
, pnum
, GFP_NOFS
);
989 BUG_ON(page
->mapping
!= inode
->i_mapping
);
990 ret
= ext4_mb_init_cache(page
, NULL
);
997 if (page
== NULL
|| !PageUptodate(page
)) {
1001 mark_page_accessed(page
);
1003 bitmap
= page_address(page
) + (poff
* sb
->s_blocksize
);
1005 /* init buddy cache */
1007 pnum
= block
/ blocks_per_page
;
1008 poff
= block
% blocks_per_page
;
1009 page
= find_or_create_page(inode
->i_mapping
, pnum
, GFP_NOFS
);
1010 if (page
== bitmap_page
) {
1012 * If both the bitmap and buddy are in
1013 * the same page we don't need to force
1018 BUG_ON(page
->mapping
!= inode
->i_mapping
);
1019 ret
= ext4_mb_init_cache(page
, bitmap
);
1026 if (page
== NULL
|| !PageUptodate(page
)) {
1030 mark_page_accessed(page
);
1032 ext4_mb_put_buddy_cache_lock(sb
, group
, num_grp_locked
);
1034 page_cache_release(bitmap_page
);
1036 page_cache_release(page
);
1041 * Locking note: This routine calls ext4_mb_init_cache(), which takes the
1042 * block group lock of all groups for this page; do not hold the BG lock when
1043 * calling this routine!
1045 static noinline_for_stack
int
1046 ext4_mb_load_buddy(struct super_block
*sb
, ext4_group_t group
,
1047 struct ext4_buddy
*e4b
)
1049 int blocks_per_page
;
1055 struct ext4_group_info
*grp
;
1056 struct ext4_sb_info
*sbi
= EXT4_SB(sb
);
1057 struct inode
*inode
= sbi
->s_buddy_cache
;
1059 mb_debug(1, "load group %u\n", group
);
1061 blocks_per_page
= PAGE_CACHE_SIZE
/ sb
->s_blocksize
;
1062 grp
= ext4_get_group_info(sb
, group
);
1064 e4b
->bd_blkbits
= sb
->s_blocksize_bits
;
1065 e4b
->bd_info
= ext4_get_group_info(sb
, group
);
1067 e4b
->bd_group
= group
;
1068 e4b
->bd_buddy_page
= NULL
;
1069 e4b
->bd_bitmap_page
= NULL
;
1070 e4b
->alloc_semp
= &grp
->alloc_sem
;
1072 /* Take the read lock on the group alloc
1073 * sem. This would make sure a parallel
1074 * ext4_mb_init_group happening on other
1075 * groups mapped by the page is blocked
1076 * till we are done with allocation
1079 down_read(e4b
->alloc_semp
);
1081 if (unlikely(EXT4_MB_GRP_NEED_INIT(grp
))) {
1082 /* we need to check for group need init flag
1083 * with alloc_semp held so that we can be sure
1084 * that new blocks didn't get added to the group
1085 * when we are loading the buddy cache
1087 up_read(e4b
->alloc_semp
);
1089 * we need full data about the group
1090 * to make a good selection
1092 ret
= ext4_mb_init_group(sb
, group
);
1095 goto repeat_load_buddy
;
1099 * the buddy cache inode stores the block bitmap
1100 * and buddy information in consecutive blocks.
1101 * So for each group we need two blocks.
1104 pnum
= block
/ blocks_per_page
;
1105 poff
= block
% blocks_per_page
;
1107 /* we could use find_or_create_page(), but it locks page
1108 * what we'd like to avoid in fast path ... */
1109 page
= find_get_page(inode
->i_mapping
, pnum
);
1110 if (page
== NULL
|| !PageUptodate(page
)) {
1113 * drop the page reference and try
1114 * to get the page with lock. If we
1115 * are not uptodate that implies
1116 * somebody just created the page but
1117 * is yet to initialize the same. So
1118 * wait for it to initialize.
1120 page_cache_release(page
);
1121 page
= find_or_create_page(inode
->i_mapping
, pnum
, GFP_NOFS
);
1123 BUG_ON(page
->mapping
!= inode
->i_mapping
);
1124 if (!PageUptodate(page
)) {
1125 ret
= ext4_mb_init_cache(page
, NULL
);
1130 mb_cmp_bitmaps(e4b
, page_address(page
) +
1131 (poff
* sb
->s_blocksize
));
1136 if (page
== NULL
|| !PageUptodate(page
)) {
1140 e4b
->bd_bitmap_page
= page
;
1141 e4b
->bd_bitmap
= page_address(page
) + (poff
* sb
->s_blocksize
);
1142 mark_page_accessed(page
);
1145 pnum
= block
/ blocks_per_page
;
1146 poff
= block
% blocks_per_page
;
1148 page
= find_get_page(inode
->i_mapping
, pnum
);
1149 if (page
== NULL
|| !PageUptodate(page
)) {
1151 page_cache_release(page
);
1152 page
= find_or_create_page(inode
->i_mapping
, pnum
, GFP_NOFS
);
1154 BUG_ON(page
->mapping
!= inode
->i_mapping
);
1155 if (!PageUptodate(page
)) {
1156 ret
= ext4_mb_init_cache(page
, e4b
->bd_bitmap
);
1165 if (page
== NULL
|| !PageUptodate(page
)) {
1169 e4b
->bd_buddy_page
= page
;
1170 e4b
->bd_buddy
= page_address(page
) + (poff
* sb
->s_blocksize
);
1171 mark_page_accessed(page
);
1173 BUG_ON(e4b
->bd_bitmap_page
== NULL
);
1174 BUG_ON(e4b
->bd_buddy_page
== NULL
);
1179 if (e4b
->bd_bitmap_page
)
1180 page_cache_release(e4b
->bd_bitmap_page
);
1181 if (e4b
->bd_buddy_page
)
1182 page_cache_release(e4b
->bd_buddy_page
);
1183 e4b
->bd_buddy
= NULL
;
1184 e4b
->bd_bitmap
= NULL
;
1186 /* Done with the buddy cache */
1187 up_read(e4b
->alloc_semp
);
1191 static void ext4_mb_unload_buddy(struct ext4_buddy
*e4b
)
1193 if (e4b
->bd_bitmap_page
)
1194 page_cache_release(e4b
->bd_bitmap_page
);
1195 if (e4b
->bd_buddy_page
)
1196 page_cache_release(e4b
->bd_buddy_page
);
1197 /* Done with the buddy cache */
1198 if (e4b
->alloc_semp
)
1199 up_read(e4b
->alloc_semp
);
1203 static int mb_find_order_for_block(struct ext4_buddy
*e4b
, int block
)
1208 BUG_ON(EXT4_MB_BITMAP(e4b
) == EXT4_MB_BUDDY(e4b
));
1209 BUG_ON(block
>= (1 << (e4b
->bd_blkbits
+ 3)));
1211 bb
= EXT4_MB_BUDDY(e4b
);
1212 while (order
<= e4b
->bd_blkbits
+ 1) {
1214 if (!mb_test_bit(block
, bb
)) {
1215 /* this block is part of buddy of order 'order' */
1218 bb
+= 1 << (e4b
->bd_blkbits
- order
);
1224 static void mb_clear_bits(void *bm
, int cur
, int len
)
1230 if ((cur
& 31) == 0 && (len
- cur
) >= 32) {
1231 /* fast path: clear whole word at once */
1232 addr
= bm
+ (cur
>> 3);
1237 mb_clear_bit(cur
, bm
);
1242 static void mb_set_bits(void *bm
, int cur
, int len
)
1248 if ((cur
& 31) == 0 && (len
- cur
) >= 32) {
1249 /* fast path: set whole word at once */
1250 addr
= bm
+ (cur
>> 3);
1255 mb_set_bit(cur
, bm
);
1260 static void mb_free_blocks(struct inode
*inode
, struct ext4_buddy
*e4b
,
1261 int first
, int count
)
1268 struct super_block
*sb
= e4b
->bd_sb
;
1270 BUG_ON(first
+ count
> (sb
->s_blocksize
<< 3));
1271 assert_spin_locked(ext4_group_lock_ptr(sb
, e4b
->bd_group
));
1272 mb_check_buddy(e4b
);
1273 mb_free_blocks_double(inode
, e4b
, first
, count
);
1275 e4b
->bd_info
->bb_free
+= count
;
1276 if (first
< e4b
->bd_info
->bb_first_free
)
1277 e4b
->bd_info
->bb_first_free
= first
;
1279 /* let's maintain fragments counter */
1281 block
= !mb_test_bit(first
- 1, EXT4_MB_BITMAP(e4b
));
1282 if (first
+ count
< EXT4_SB(sb
)->s_mb_maxs
[0])
1283 max
= !mb_test_bit(first
+ count
, EXT4_MB_BITMAP(e4b
));
1285 e4b
->bd_info
->bb_fragments
--;
1286 else if (!block
&& !max
)
1287 e4b
->bd_info
->bb_fragments
++;
1289 /* let's maintain buddy itself */
1290 while (count
-- > 0) {
1294 if (!mb_test_bit(block
, EXT4_MB_BITMAP(e4b
))) {
1295 ext4_fsblk_t blocknr
;
1297 blocknr
= ext4_group_first_block_no(sb
, e4b
->bd_group
);
1299 ext4_grp_locked_error(sb
, e4b
->bd_group
,
1300 inode
? inode
->i_ino
: 0,
1302 "freeing already freed block "
1305 mb_clear_bit(block
, EXT4_MB_BITMAP(e4b
));
1306 e4b
->bd_info
->bb_counters
[order
]++;
1308 /* start of the buddy */
1309 buddy
= mb_find_buddy(e4b
, order
, &max
);
1313 if (mb_test_bit(block
, buddy
) ||
1314 mb_test_bit(block
+ 1, buddy
))
1317 /* both the buddies are free, try to coalesce them */
1318 buddy2
= mb_find_buddy(e4b
, order
+ 1, &max
);
1324 /* for special purposes, we don't set
1325 * free bits in bitmap */
1326 mb_set_bit(block
, buddy
);
1327 mb_set_bit(block
+ 1, buddy
);
1329 e4b
->bd_info
->bb_counters
[order
]--;
1330 e4b
->bd_info
->bb_counters
[order
]--;
1334 e4b
->bd_info
->bb_counters
[order
]++;
1336 mb_clear_bit(block
, buddy2
);
1340 mb_set_largest_free_order(sb
, e4b
->bd_info
);
1341 mb_check_buddy(e4b
);
1344 static int mb_find_extent(struct ext4_buddy
*e4b
, int order
, int block
,
1345 int needed
, struct ext4_free_extent
*ex
)
1352 assert_spin_locked(ext4_group_lock_ptr(e4b
->bd_sb
, e4b
->bd_group
));
1355 buddy
= mb_find_buddy(e4b
, order
, &max
);
1356 BUG_ON(buddy
== NULL
);
1357 BUG_ON(block
>= max
);
1358 if (mb_test_bit(block
, buddy
)) {
1365 /* FIXME dorp order completely ? */
1366 if (likely(order
== 0)) {
1367 /* find actual order */
1368 order
= mb_find_order_for_block(e4b
, block
);
1369 block
= block
>> order
;
1372 ex
->fe_len
= 1 << order
;
1373 ex
->fe_start
= block
<< order
;
1374 ex
->fe_group
= e4b
->bd_group
;
1376 /* calc difference from given start */
1377 next
= next
- ex
->fe_start
;
1379 ex
->fe_start
+= next
;
1381 while (needed
> ex
->fe_len
&&
1382 (buddy
= mb_find_buddy(e4b
, order
, &max
))) {
1384 if (block
+ 1 >= max
)
1387 next
= (block
+ 1) * (1 << order
);
1388 if (mb_test_bit(next
, EXT4_MB_BITMAP(e4b
)))
1391 ord
= mb_find_order_for_block(e4b
, next
);
1394 block
= next
>> order
;
1395 ex
->fe_len
+= 1 << order
;
1398 BUG_ON(ex
->fe_start
+ ex
->fe_len
> (1 << (e4b
->bd_blkbits
+ 3)));
1402 static int mb_mark_used(struct ext4_buddy
*e4b
, struct ext4_free_extent
*ex
)
1408 int start
= ex
->fe_start
;
1409 int len
= ex
->fe_len
;
1414 BUG_ON(start
+ len
> (e4b
->bd_sb
->s_blocksize
<< 3));
1415 BUG_ON(e4b
->bd_group
!= ex
->fe_group
);
1416 assert_spin_locked(ext4_group_lock_ptr(e4b
->bd_sb
, e4b
->bd_group
));
1417 mb_check_buddy(e4b
);
1418 mb_mark_used_double(e4b
, start
, len
);
1420 e4b
->bd_info
->bb_free
-= len
;
1421 if (e4b
->bd_info
->bb_first_free
== start
)
1422 e4b
->bd_info
->bb_first_free
+= len
;
1424 /* let's maintain fragments counter */
1426 mlen
= !mb_test_bit(start
- 1, EXT4_MB_BITMAP(e4b
));
1427 if (start
+ len
< EXT4_SB(e4b
->bd_sb
)->s_mb_maxs
[0])
1428 max
= !mb_test_bit(start
+ len
, EXT4_MB_BITMAP(e4b
));
1430 e4b
->bd_info
->bb_fragments
++;
1431 else if (!mlen
&& !max
)
1432 e4b
->bd_info
->bb_fragments
--;
1434 /* let's maintain buddy itself */
1436 ord
= mb_find_order_for_block(e4b
, start
);
1438 if (((start
>> ord
) << ord
) == start
&& len
>= (1 << ord
)) {
1439 /* the whole chunk may be allocated at once! */
1441 buddy
= mb_find_buddy(e4b
, ord
, &max
);
1442 BUG_ON((start
>> ord
) >= max
);
1443 mb_set_bit(start
>> ord
, buddy
);
1444 e4b
->bd_info
->bb_counters
[ord
]--;
1451 /* store for history */
1453 ret
= len
| (ord
<< 16);
1455 /* we have to split large buddy */
1457 buddy
= mb_find_buddy(e4b
, ord
, &max
);
1458 mb_set_bit(start
>> ord
, buddy
);
1459 e4b
->bd_info
->bb_counters
[ord
]--;
1462 cur
= (start
>> ord
) & ~1U;
1463 buddy
= mb_find_buddy(e4b
, ord
, &max
);
1464 mb_clear_bit(cur
, buddy
);
1465 mb_clear_bit(cur
+ 1, buddy
);
1466 e4b
->bd_info
->bb_counters
[ord
]++;
1467 e4b
->bd_info
->bb_counters
[ord
]++;
1469 mb_set_largest_free_order(e4b
->bd_sb
, e4b
->bd_info
);
1471 mb_set_bits(EXT4_MB_BITMAP(e4b
), ex
->fe_start
, len0
);
1472 mb_check_buddy(e4b
);
1478 * Must be called under group lock!
1480 static void ext4_mb_use_best_found(struct ext4_allocation_context
*ac
,
1481 struct ext4_buddy
*e4b
)
1483 struct ext4_sb_info
*sbi
= EXT4_SB(ac
->ac_sb
);
1486 BUG_ON(ac
->ac_b_ex
.fe_group
!= e4b
->bd_group
);
1487 BUG_ON(ac
->ac_status
== AC_STATUS_FOUND
);
1489 ac
->ac_b_ex
.fe_len
= min(ac
->ac_b_ex
.fe_len
, ac
->ac_g_ex
.fe_len
);
1490 ac
->ac_b_ex
.fe_logical
= ac
->ac_g_ex
.fe_logical
;
1491 ret
= mb_mark_used(e4b
, &ac
->ac_b_ex
);
1493 /* preallocation can change ac_b_ex, thus we store actually
1494 * allocated blocks for history */
1495 ac
->ac_f_ex
= ac
->ac_b_ex
;
1497 ac
->ac_status
= AC_STATUS_FOUND
;
1498 ac
->ac_tail
= ret
& 0xffff;
1499 ac
->ac_buddy
= ret
>> 16;
1502 * take the page reference. We want the page to be pinned
1503 * so that we don't get a ext4_mb_init_cache_call for this
1504 * group until we update the bitmap. That would mean we
1505 * double allocate blocks. The reference is dropped
1506 * in ext4_mb_release_context
1508 ac
->ac_bitmap_page
= e4b
->bd_bitmap_page
;
1509 get_page(ac
->ac_bitmap_page
);
1510 ac
->ac_buddy_page
= e4b
->bd_buddy_page
;
1511 get_page(ac
->ac_buddy_page
);
1512 /* on allocation we use ac to track the held semaphore */
1513 ac
->alloc_semp
= e4b
->alloc_semp
;
1514 e4b
->alloc_semp
= NULL
;
1515 /* store last allocated for subsequent stream allocation */
1516 if (ac
->ac_flags
& EXT4_MB_STREAM_ALLOC
) {
1517 spin_lock(&sbi
->s_md_lock
);
1518 sbi
->s_mb_last_group
= ac
->ac_f_ex
.fe_group
;
1519 sbi
->s_mb_last_start
= ac
->ac_f_ex
.fe_start
;
1520 spin_unlock(&sbi
->s_md_lock
);
1525 * regular allocator, for general purposes allocation
1528 static void ext4_mb_check_limits(struct ext4_allocation_context
*ac
,
1529 struct ext4_buddy
*e4b
,
1532 struct ext4_sb_info
*sbi
= EXT4_SB(ac
->ac_sb
);
1533 struct ext4_free_extent
*bex
= &ac
->ac_b_ex
;
1534 struct ext4_free_extent
*gex
= &ac
->ac_g_ex
;
1535 struct ext4_free_extent ex
;
1538 if (ac
->ac_status
== AC_STATUS_FOUND
)
1541 * We don't want to scan for a whole year
1543 if (ac
->ac_found
> sbi
->s_mb_max_to_scan
&&
1544 !(ac
->ac_flags
& EXT4_MB_HINT_FIRST
)) {
1545 ac
->ac_status
= AC_STATUS_BREAK
;
1550 * Haven't found good chunk so far, let's continue
1552 if (bex
->fe_len
< gex
->fe_len
)
1555 if ((finish_group
|| ac
->ac_found
> sbi
->s_mb_min_to_scan
)
1556 && bex
->fe_group
== e4b
->bd_group
) {
1557 /* recheck chunk's availability - we don't know
1558 * when it was found (within this lock-unlock
1560 max
= mb_find_extent(e4b
, 0, bex
->fe_start
, gex
->fe_len
, &ex
);
1561 if (max
>= gex
->fe_len
) {
1562 ext4_mb_use_best_found(ac
, e4b
);
1569 * The routine checks whether found extent is good enough. If it is,
1570 * then the extent gets marked used and flag is set to the context
1571 * to stop scanning. Otherwise, the extent is compared with the
1572 * previous found extent and if new one is better, then it's stored
1573 * in the context. Later, the best found extent will be used, if
1574 * mballoc can't find good enough extent.
1576 * FIXME: real allocation policy is to be designed yet!
1578 static void ext4_mb_measure_extent(struct ext4_allocation_context
*ac
,
1579 struct ext4_free_extent
*ex
,
1580 struct ext4_buddy
*e4b
)
1582 struct ext4_free_extent
*bex
= &ac
->ac_b_ex
;
1583 struct ext4_free_extent
*gex
= &ac
->ac_g_ex
;
1585 BUG_ON(ex
->fe_len
<= 0);
1586 BUG_ON(ex
->fe_len
> EXT4_BLOCKS_PER_GROUP(ac
->ac_sb
));
1587 BUG_ON(ex
->fe_start
>= EXT4_BLOCKS_PER_GROUP(ac
->ac_sb
));
1588 BUG_ON(ac
->ac_status
!= AC_STATUS_CONTINUE
);
1593 * The special case - take what you catch first
1595 if (unlikely(ac
->ac_flags
& EXT4_MB_HINT_FIRST
)) {
1597 ext4_mb_use_best_found(ac
, e4b
);
1602 * Let's check whether the chuck is good enough
1604 if (ex
->fe_len
== gex
->fe_len
) {
1606 ext4_mb_use_best_found(ac
, e4b
);
1611 * If this is first found extent, just store it in the context
1613 if (bex
->fe_len
== 0) {
1619 * If new found extent is better, store it in the context
1621 if (bex
->fe_len
< gex
->fe_len
) {
1622 /* if the request isn't satisfied, any found extent
1623 * larger than previous best one is better */
1624 if (ex
->fe_len
> bex
->fe_len
)
1626 } else if (ex
->fe_len
> gex
->fe_len
) {
1627 /* if the request is satisfied, then we try to find
1628 * an extent that still satisfy the request, but is
1629 * smaller than previous one */
1630 if (ex
->fe_len
< bex
->fe_len
)
1634 ext4_mb_check_limits(ac
, e4b
, 0);
1637 static noinline_for_stack
1638 int ext4_mb_try_best_found(struct ext4_allocation_context
*ac
,
1639 struct ext4_buddy
*e4b
)
1641 struct ext4_free_extent ex
= ac
->ac_b_ex
;
1642 ext4_group_t group
= ex
.fe_group
;
1646 BUG_ON(ex
.fe_len
<= 0);
1647 err
= ext4_mb_load_buddy(ac
->ac_sb
, group
, e4b
);
1651 ext4_lock_group(ac
->ac_sb
, group
);
1652 max
= mb_find_extent(e4b
, 0, ex
.fe_start
, ex
.fe_len
, &ex
);
1656 ext4_mb_use_best_found(ac
, e4b
);
1659 ext4_unlock_group(ac
->ac_sb
, group
);
1660 ext4_mb_unload_buddy(e4b
);
1665 static noinline_for_stack
1666 int ext4_mb_find_by_goal(struct ext4_allocation_context
*ac
,
1667 struct ext4_buddy
*e4b
)
1669 ext4_group_t group
= ac
->ac_g_ex
.fe_group
;
1672 struct ext4_sb_info
*sbi
= EXT4_SB(ac
->ac_sb
);
1673 struct ext4_free_extent ex
;
1675 if (!(ac
->ac_flags
& EXT4_MB_HINT_TRY_GOAL
))
1678 err
= ext4_mb_load_buddy(ac
->ac_sb
, group
, e4b
);
1682 ext4_lock_group(ac
->ac_sb
, group
);
1683 max
= mb_find_extent(e4b
, 0, ac
->ac_g_ex
.fe_start
,
1684 ac
->ac_g_ex
.fe_len
, &ex
);
1686 if (max
>= ac
->ac_g_ex
.fe_len
&& ac
->ac_g_ex
.fe_len
== sbi
->s_stripe
) {
1689 start
= ext4_group_first_block_no(ac
->ac_sb
, e4b
->bd_group
) +
1691 /* use do_div to get remainder (would be 64-bit modulo) */
1692 if (do_div(start
, sbi
->s_stripe
) == 0) {
1695 ext4_mb_use_best_found(ac
, e4b
);
1697 } else if (max
>= ac
->ac_g_ex
.fe_len
) {
1698 BUG_ON(ex
.fe_len
<= 0);
1699 BUG_ON(ex
.fe_group
!= ac
->ac_g_ex
.fe_group
);
1700 BUG_ON(ex
.fe_start
!= ac
->ac_g_ex
.fe_start
);
1703 ext4_mb_use_best_found(ac
, e4b
);
1704 } else if (max
> 0 && (ac
->ac_flags
& EXT4_MB_HINT_MERGE
)) {
1705 /* Sometimes, caller may want to merge even small
1706 * number of blocks to an existing extent */
1707 BUG_ON(ex
.fe_len
<= 0);
1708 BUG_ON(ex
.fe_group
!= ac
->ac_g_ex
.fe_group
);
1709 BUG_ON(ex
.fe_start
!= ac
->ac_g_ex
.fe_start
);
1712 ext4_mb_use_best_found(ac
, e4b
);
1714 ext4_unlock_group(ac
->ac_sb
, group
);
1715 ext4_mb_unload_buddy(e4b
);
1721 * The routine scans buddy structures (not bitmap!) from given order
1722 * to max order and tries to find big enough chunk to satisfy the req
1724 static noinline_for_stack
1725 void ext4_mb_simple_scan_group(struct ext4_allocation_context
*ac
,
1726 struct ext4_buddy
*e4b
)
1728 struct super_block
*sb
= ac
->ac_sb
;
1729 struct ext4_group_info
*grp
= e4b
->bd_info
;
1735 BUG_ON(ac
->ac_2order
<= 0);
1736 for (i
= ac
->ac_2order
; i
<= sb
->s_blocksize_bits
+ 1; i
++) {
1737 if (grp
->bb_counters
[i
] == 0)
1740 buddy
= mb_find_buddy(e4b
, i
, &max
);
1741 BUG_ON(buddy
== NULL
);
1743 k
= mb_find_next_zero_bit(buddy
, max
, 0);
1748 ac
->ac_b_ex
.fe_len
= 1 << i
;
1749 ac
->ac_b_ex
.fe_start
= k
<< i
;
1750 ac
->ac_b_ex
.fe_group
= e4b
->bd_group
;
1752 ext4_mb_use_best_found(ac
, e4b
);
1754 BUG_ON(ac
->ac_b_ex
.fe_len
!= ac
->ac_g_ex
.fe_len
);
1756 if (EXT4_SB(sb
)->s_mb_stats
)
1757 atomic_inc(&EXT4_SB(sb
)->s_bal_2orders
);
1764 * The routine scans the group and measures all found extents.
1765 * In order to optimize scanning, caller must pass number of
1766 * free blocks in the group, so the routine can know upper limit.
1768 static noinline_for_stack
1769 void ext4_mb_complex_scan_group(struct ext4_allocation_context
*ac
,
1770 struct ext4_buddy
*e4b
)
1772 struct super_block
*sb
= ac
->ac_sb
;
1773 void *bitmap
= EXT4_MB_BITMAP(e4b
);
1774 struct ext4_free_extent ex
;
1778 free
= e4b
->bd_info
->bb_free
;
1781 i
= e4b
->bd_info
->bb_first_free
;
1783 while (free
&& ac
->ac_status
== AC_STATUS_CONTINUE
) {
1784 i
= mb_find_next_zero_bit(bitmap
,
1785 EXT4_BLOCKS_PER_GROUP(sb
), i
);
1786 if (i
>= EXT4_BLOCKS_PER_GROUP(sb
)) {
1788 * IF we have corrupt bitmap, we won't find any
1789 * free blocks even though group info says we
1790 * we have free blocks
1792 ext4_grp_locked_error(sb
, e4b
->bd_group
, 0, 0,
1793 "%d free blocks as per "
1794 "group info. But bitmap says 0",
1799 mb_find_extent(e4b
, 0, i
, ac
->ac_g_ex
.fe_len
, &ex
);
1800 BUG_ON(ex
.fe_len
<= 0);
1801 if (free
< ex
.fe_len
) {
1802 ext4_grp_locked_error(sb
, e4b
->bd_group
, 0, 0,
1803 "%d free blocks as per "
1804 "group info. But got %d blocks",
1807 * The number of free blocks differs. This mostly
1808 * indicate that the bitmap is corrupt. So exit
1809 * without claiming the space.
1814 ext4_mb_measure_extent(ac
, &ex
, e4b
);
1820 ext4_mb_check_limits(ac
, e4b
, 1);
1824 * This is a special case for storages like raid5
1825 * we try to find stripe-aligned chunks for stripe-size requests
1826 * XXX should do so at least for multiples of stripe size as well
1828 static noinline_for_stack
1829 void ext4_mb_scan_aligned(struct ext4_allocation_context
*ac
,
1830 struct ext4_buddy
*e4b
)
1832 struct super_block
*sb
= ac
->ac_sb
;
1833 struct ext4_sb_info
*sbi
= EXT4_SB(sb
);
1834 void *bitmap
= EXT4_MB_BITMAP(e4b
);
1835 struct ext4_free_extent ex
;
1836 ext4_fsblk_t first_group_block
;
1841 BUG_ON(sbi
->s_stripe
== 0);
1843 /* find first stripe-aligned block in group */
1844 first_group_block
= ext4_group_first_block_no(sb
, e4b
->bd_group
);
1846 a
= first_group_block
+ sbi
->s_stripe
- 1;
1847 do_div(a
, sbi
->s_stripe
);
1848 i
= (a
* sbi
->s_stripe
) - first_group_block
;
1850 while (i
< EXT4_BLOCKS_PER_GROUP(sb
)) {
1851 if (!mb_test_bit(i
, bitmap
)) {
1852 max
= mb_find_extent(e4b
, 0, i
, sbi
->s_stripe
, &ex
);
1853 if (max
>= sbi
->s_stripe
) {
1856 ext4_mb_use_best_found(ac
, e4b
);
1864 /* This is now called BEFORE we load the buddy bitmap. */
1865 static int ext4_mb_good_group(struct ext4_allocation_context
*ac
,
1866 ext4_group_t group
, int cr
)
1868 unsigned free
, fragments
;
1869 int flex_size
= ext4_flex_bg_size(EXT4_SB(ac
->ac_sb
));
1870 struct ext4_group_info
*grp
= ext4_get_group_info(ac
->ac_sb
, group
);
1872 BUG_ON(cr
< 0 || cr
>= 4);
1874 /* We only do this if the grp has never been initialized */
1875 if (unlikely(EXT4_MB_GRP_NEED_INIT(grp
))) {
1876 int ret
= ext4_mb_init_group(ac
->ac_sb
, group
);
1881 free
= grp
->bb_free
;
1882 fragments
= grp
->bb_fragments
;
1890 BUG_ON(ac
->ac_2order
== 0);
1892 if (grp
->bb_largest_free_order
< ac
->ac_2order
)
1895 /* Avoid using the first bg of a flexgroup for data files */
1896 if ((ac
->ac_flags
& EXT4_MB_HINT_DATA
) &&
1897 (flex_size
>= EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME
) &&
1898 ((group
% flex_size
) == 0))
1903 if ((free
/ fragments
) >= ac
->ac_g_ex
.fe_len
)
1907 if (free
>= ac
->ac_g_ex
.fe_len
)
1920 * lock the group_info alloc_sem of all the groups
1921 * belonging to the same buddy cache page. This
1922 * make sure other parallel operation on the buddy
1923 * cache doesn't happen whild holding the buddy cache
1926 int ext4_mb_get_buddy_cache_lock(struct super_block
*sb
, ext4_group_t group
)
1930 int blocks_per_page
;
1931 int groups_per_page
;
1932 ext4_group_t ngroups
= ext4_get_groups_count(sb
);
1933 ext4_group_t first_group
;
1934 struct ext4_group_info
*grp
;
1936 blocks_per_page
= PAGE_CACHE_SIZE
/ sb
->s_blocksize
;
1938 * the buddy cache inode stores the block bitmap
1939 * and buddy information in consecutive blocks.
1940 * So for each group we need two blocks.
1943 pnum
= block
/ blocks_per_page
;
1944 first_group
= pnum
* blocks_per_page
/ 2;
1946 groups_per_page
= blocks_per_page
>> 1;
1947 if (groups_per_page
== 0)
1948 groups_per_page
= 1;
1949 /* read all groups the page covers into the cache */
1950 for (i
= 0; i
< groups_per_page
; i
++) {
1952 if ((first_group
+ i
) >= ngroups
)
1954 grp
= ext4_get_group_info(sb
, first_group
+ i
);
1955 /* take all groups write allocation
1956 * semaphore. This make sure there is
1957 * no block allocation going on in any
1960 down_write_nested(&grp
->alloc_sem
, i
);
1965 void ext4_mb_put_buddy_cache_lock(struct super_block
*sb
,
1966 ext4_group_t group
, int locked_group
)
1970 int blocks_per_page
;
1971 ext4_group_t first_group
;
1972 struct ext4_group_info
*grp
;
1974 blocks_per_page
= PAGE_CACHE_SIZE
/ sb
->s_blocksize
;
1976 * the buddy cache inode stores the block bitmap
1977 * and buddy information in consecutive blocks.
1978 * So for each group we need two blocks.
1981 pnum
= block
/ blocks_per_page
;
1982 first_group
= pnum
* blocks_per_page
/ 2;
1983 /* release locks on all the groups */
1984 for (i
= 0; i
< locked_group
; i
++) {
1986 grp
= ext4_get_group_info(sb
, first_group
+ i
);
1987 /* take all groups write allocation
1988 * semaphore. This make sure there is
1989 * no block allocation going on in any
1992 up_write(&grp
->alloc_sem
);
1997 static noinline_for_stack
int
1998 ext4_mb_regular_allocator(struct ext4_allocation_context
*ac
)
2000 ext4_group_t ngroups
, group
, i
;
2003 struct ext4_sb_info
*sbi
;
2004 struct super_block
*sb
;
2005 struct ext4_buddy e4b
;
2009 ngroups
= ext4_get_groups_count(sb
);
2010 /* non-extent files are limited to low blocks/groups */
2011 if (!(ext4_test_inode_flag(ac
->ac_inode
, EXT4_INODE_EXTENTS
)))
2012 ngroups
= sbi
->s_blockfile_groups
;
2014 BUG_ON(ac
->ac_status
== AC_STATUS_FOUND
);
2016 /* first, try the goal */
2017 err
= ext4_mb_find_by_goal(ac
, &e4b
);
2018 if (err
|| ac
->ac_status
== AC_STATUS_FOUND
)
2021 if (unlikely(ac
->ac_flags
& EXT4_MB_HINT_GOAL_ONLY
))
2025 * ac->ac2_order is set only if the fe_len is a power of 2
2026 * if ac2_order is set we also set criteria to 0 so that we
2027 * try exact allocation using buddy.
2029 i
= fls(ac
->ac_g_ex
.fe_len
);
2032 * We search using buddy data only if the order of the request
2033 * is greater than equal to the sbi_s_mb_order2_reqs
2034 * You can tune it via /sys/fs/ext4/<partition>/mb_order2_req
2036 if (i
>= sbi
->s_mb_order2_reqs
) {
2038 * This should tell if fe_len is exactly power of 2
2040 if ((ac
->ac_g_ex
.fe_len
& (~(1 << (i
- 1)))) == 0)
2041 ac
->ac_2order
= i
- 1;
2044 /* if stream allocation is enabled, use global goal */
2045 if (ac
->ac_flags
& EXT4_MB_STREAM_ALLOC
) {
2046 /* TBD: may be hot point */
2047 spin_lock(&sbi
->s_md_lock
);
2048 ac
->ac_g_ex
.fe_group
= sbi
->s_mb_last_group
;
2049 ac
->ac_g_ex
.fe_start
= sbi
->s_mb_last_start
;
2050 spin_unlock(&sbi
->s_md_lock
);
2053 /* Let's just scan groups to find more-less suitable blocks */
2054 cr
= ac
->ac_2order
? 0 : 1;
2056 * cr == 0 try to get exact allocation,
2057 * cr == 3 try to get anything
2060 for (; cr
< 4 && ac
->ac_status
== AC_STATUS_CONTINUE
; cr
++) {
2061 ac
->ac_criteria
= cr
;
2063 * searching for the right group start
2064 * from the goal value specified
2066 group
= ac
->ac_g_ex
.fe_group
;
2068 for (i
= 0; i
< ngroups
; group
++, i
++) {
2069 if (group
== ngroups
)
2072 /* This now checks without needing the buddy page */
2073 if (!ext4_mb_good_group(ac
, group
, cr
))
2076 err
= ext4_mb_load_buddy(sb
, group
, &e4b
);
2080 ext4_lock_group(sb
, group
);
2083 * We need to check again after locking the
2086 if (!ext4_mb_good_group(ac
, group
, cr
)) {
2087 ext4_unlock_group(sb
, group
);
2088 ext4_mb_unload_buddy(&e4b
);
2092 ac
->ac_groups_scanned
++;
2094 ext4_mb_simple_scan_group(ac
, &e4b
);
2096 ac
->ac_g_ex
.fe_len
== sbi
->s_stripe
)
2097 ext4_mb_scan_aligned(ac
, &e4b
);
2099 ext4_mb_complex_scan_group(ac
, &e4b
);
2101 ext4_unlock_group(sb
, group
);
2102 ext4_mb_unload_buddy(&e4b
);
2104 if (ac
->ac_status
!= AC_STATUS_CONTINUE
)
2109 if (ac
->ac_b_ex
.fe_len
> 0 && ac
->ac_status
!= AC_STATUS_FOUND
&&
2110 !(ac
->ac_flags
& EXT4_MB_HINT_FIRST
)) {
2112 * We've been searching too long. Let's try to allocate
2113 * the best chunk we've found so far
2116 ext4_mb_try_best_found(ac
, &e4b
);
2117 if (ac
->ac_status
!= AC_STATUS_FOUND
) {
2119 * Someone more lucky has already allocated it.
2120 * The only thing we can do is just take first
2122 printk(KERN_DEBUG "EXT4-fs: someone won our chunk\n");
2124 ac
->ac_b_ex
.fe_group
= 0;
2125 ac
->ac_b_ex
.fe_start
= 0;
2126 ac
->ac_b_ex
.fe_len
= 0;
2127 ac
->ac_status
= AC_STATUS_CONTINUE
;
2128 ac
->ac_flags
|= EXT4_MB_HINT_FIRST
;
2130 atomic_inc(&sbi
->s_mb_lost_chunks
);
2138 static void *ext4_mb_seq_groups_start(struct seq_file
*seq
, loff_t
*pos
)
2140 struct super_block
*sb
= seq
->private;
2143 if (*pos
< 0 || *pos
>= ext4_get_groups_count(sb
))
2146 return (void *) ((unsigned long) group
);
2149 static void *ext4_mb_seq_groups_next(struct seq_file
*seq
, void *v
, loff_t
*pos
)
2151 struct super_block
*sb
= seq
->private;
2155 if (*pos
< 0 || *pos
>= ext4_get_groups_count(sb
))
2158 return (void *) ((unsigned long) group
);
2161 static int ext4_mb_seq_groups_show(struct seq_file
*seq
, void *v
)
2163 struct super_block
*sb
= seq
->private;
2164 ext4_group_t group
= (ext4_group_t
) ((unsigned long) v
);
2167 struct ext4_buddy e4b
;
2169 struct ext4_group_info info
;
2170 ext4_grpblk_t counters
[16];
2175 seq_printf(seq
, "#%-5s: %-5s %-5s %-5s "
2176 "[ %-5s %-5s %-5s %-5s %-5s %-5s %-5s "
2177 "%-5s %-5s %-5s %-5s %-5s %-5s %-5s ]\n",
2178 "group", "free", "frags", "first",
2179 "2^0", "2^1", "2^2", "2^3", "2^4", "2^5", "2^6",
2180 "2^7", "2^8", "2^9", "2^10", "2^11", "2^12", "2^13");
2182 i
= (sb
->s_blocksize_bits
+ 2) * sizeof(sg
.info
.bb_counters
[0]) +
2183 sizeof(struct ext4_group_info
);
2184 err
= ext4_mb_load_buddy(sb
, group
, &e4b
);
2186 seq_printf(seq
, "#%-5u: I/O error\n", group
);
2189 ext4_lock_group(sb
, group
);
2190 memcpy(&sg
, ext4_get_group_info(sb
, group
), i
);
2191 ext4_unlock_group(sb
, group
);
2192 ext4_mb_unload_buddy(&e4b
);
2194 seq_printf(seq
, "#%-5u: %-5u %-5u %-5u [", group
, sg
.info
.bb_free
,
2195 sg
.info
.bb_fragments
, sg
.info
.bb_first_free
);
2196 for (i
= 0; i
<= 13; i
++)
2197 seq_printf(seq
, " %-5u", i
<= sb
->s_blocksize_bits
+ 1 ?
2198 sg
.info
.bb_counters
[i
] : 0);
2199 seq_printf(seq
, " ]\n");
2204 static void ext4_mb_seq_groups_stop(struct seq_file
*seq
, void *v
)
2208 static const struct seq_operations ext4_mb_seq_groups_ops
= {
2209 .start
= ext4_mb_seq_groups_start
,
2210 .next
= ext4_mb_seq_groups_next
,
2211 .stop
= ext4_mb_seq_groups_stop
,
2212 .show
= ext4_mb_seq_groups_show
,
2215 static int ext4_mb_seq_groups_open(struct inode
*inode
, struct file
*file
)
2217 struct super_block
*sb
= PDE(inode
)->data
;
2220 rc
= seq_open(file
, &ext4_mb_seq_groups_ops
);
2222 struct seq_file
*m
= file
->private_data
;
2229 static const struct file_operations ext4_mb_seq_groups_fops
= {
2230 .owner
= THIS_MODULE
,
2231 .open
= ext4_mb_seq_groups_open
,
2233 .llseek
= seq_lseek
,
2234 .release
= seq_release
,
2238 /* Create and initialize ext4_group_info data for the given group. */
2239 int ext4_mb_add_groupinfo(struct super_block
*sb
, ext4_group_t group
,
2240 struct ext4_group_desc
*desc
)
2244 struct ext4_sb_info
*sbi
= EXT4_SB(sb
);
2245 struct ext4_group_info
**meta_group_info
;
2248 * First check if this group is the first of a reserved block.
2249 * If it's true, we have to allocate a new table of pointers
2250 * to ext4_group_info structures
2252 if (group
% EXT4_DESC_PER_BLOCK(sb
) == 0) {
2253 metalen
= sizeof(*meta_group_info
) <<
2254 EXT4_DESC_PER_BLOCK_BITS(sb
);
2255 meta_group_info
= kmalloc(metalen
, GFP_KERNEL
);
2256 if (meta_group_info
== NULL
) {
2257 printk(KERN_ERR
"EXT4-fs: can't allocate mem for a "
2259 goto exit_meta_group_info
;
2261 sbi
->s_group_info
[group
>> EXT4_DESC_PER_BLOCK_BITS(sb
)] =
2266 * calculate needed size. if change bb_counters size,
2267 * don't forget about ext4_mb_generate_buddy()
2269 len
= offsetof(typeof(**meta_group_info
),
2270 bb_counters
[sb
->s_blocksize_bits
+ 2]);
2273 sbi
->s_group_info
[group
>> EXT4_DESC_PER_BLOCK_BITS(sb
)];
2274 i
= group
& (EXT4_DESC_PER_BLOCK(sb
) - 1);
2276 meta_group_info
[i
] = kzalloc(len
, GFP_KERNEL
);
2277 if (meta_group_info
[i
] == NULL
) {
2278 printk(KERN_ERR
"EXT4-fs: can't allocate buddy mem\n");
2279 goto exit_group_info
;
2281 set_bit(EXT4_GROUP_INFO_NEED_INIT_BIT
,
2282 &(meta_group_info
[i
]->bb_state
));
2285 * initialize bb_free to be able to skip
2286 * empty groups without initialization
2288 if (desc
->bg_flags
& cpu_to_le16(EXT4_BG_BLOCK_UNINIT
)) {
2289 meta_group_info
[i
]->bb_free
=
2290 ext4_free_blocks_after_init(sb
, group
, desc
);
2292 meta_group_info
[i
]->bb_free
=
2293 ext4_free_blks_count(sb
, desc
);
2296 INIT_LIST_HEAD(&meta_group_info
[i
]->bb_prealloc_list
);
2297 init_rwsem(&meta_group_info
[i
]->alloc_sem
);
2298 meta_group_info
[i
]->bb_free_root
= RB_ROOT
;
2299 meta_group_info
[i
]->bb_largest_free_order
= -1; /* uninit */
2303 struct buffer_head
*bh
;
2304 meta_group_info
[i
]->bb_bitmap
=
2305 kmalloc(sb
->s_blocksize
, GFP_KERNEL
);
2306 BUG_ON(meta_group_info
[i
]->bb_bitmap
== NULL
);
2307 bh
= ext4_read_block_bitmap(sb
, group
);
2309 memcpy(meta_group_info
[i
]->bb_bitmap
, bh
->b_data
,
2318 /* If a meta_group_info table has been allocated, release it now */
2319 if (group
% EXT4_DESC_PER_BLOCK(sb
) == 0)
2320 kfree(sbi
->s_group_info
[group
>> EXT4_DESC_PER_BLOCK_BITS(sb
)]);
2321 exit_meta_group_info
:
2323 } /* ext4_mb_add_groupinfo */
2325 static int ext4_mb_init_backend(struct super_block
*sb
)
2327 ext4_group_t ngroups
= ext4_get_groups_count(sb
);
2329 struct ext4_sb_info
*sbi
= EXT4_SB(sb
);
2330 struct ext4_super_block
*es
= sbi
->s_es
;
2331 int num_meta_group_infos
;
2332 int num_meta_group_infos_max
;
2334 struct ext4_group_desc
*desc
;
2336 /* This is the number of blocks used by GDT */
2337 num_meta_group_infos
= (ngroups
+ EXT4_DESC_PER_BLOCK(sb
) -
2338 1) >> EXT4_DESC_PER_BLOCK_BITS(sb
);
2341 * This is the total number of blocks used by GDT including
2342 * the number of reserved blocks for GDT.
2343 * The s_group_info array is allocated with this value
2344 * to allow a clean online resize without a complex
2345 * manipulation of pointer.
2346 * The drawback is the unused memory when no resize
2347 * occurs but it's very low in terms of pages
2348 * (see comments below)
2349 * Need to handle this properly when META_BG resizing is allowed
2351 num_meta_group_infos_max
= num_meta_group_infos
+
2352 le16_to_cpu(es
->s_reserved_gdt_blocks
);
2355 * array_size is the size of s_group_info array. We round it
2356 * to the next power of two because this approximation is done
2357 * internally by kmalloc so we can have some more memory
2358 * for free here (e.g. may be used for META_BG resize).
2361 while (array_size
< sizeof(*sbi
->s_group_info
) *
2362 num_meta_group_infos_max
)
2363 array_size
= array_size
<< 1;
2364 /* An 8TB filesystem with 64-bit pointers requires a 4096 byte
2365 * kmalloc. A 128kb malloc should suffice for a 256TB filesystem.
2366 * So a two level scheme suffices for now. */
2367 sbi
->s_group_info
= kmalloc(array_size
, GFP_KERNEL
);
2368 if (sbi
->s_group_info
== NULL
) {
2369 printk(KERN_ERR
"EXT4-fs: can't allocate buddy meta group\n");
2372 sbi
->s_buddy_cache
= new_inode(sb
);
2373 if (sbi
->s_buddy_cache
== NULL
) {
2374 printk(KERN_ERR
"EXT4-fs: can't get new inode\n");
2377 EXT4_I(sbi
->s_buddy_cache
)->i_disksize
= 0;
2378 for (i
= 0; i
< ngroups
; i
++) {
2379 desc
= ext4_get_group_desc(sb
, i
, NULL
);
2382 "EXT4-fs: can't read descriptor %u\n", i
);
2385 if (ext4_mb_add_groupinfo(sb
, i
, desc
) != 0)
2393 kfree(ext4_get_group_info(sb
, i
));
2394 i
= num_meta_group_infos
;
2396 kfree(sbi
->s_group_info
[i
]);
2397 iput(sbi
->s_buddy_cache
);
2399 kfree(sbi
->s_group_info
);
2403 int ext4_mb_init(struct super_block
*sb
, int needs_recovery
)
2405 struct ext4_sb_info
*sbi
= EXT4_SB(sb
);
2411 i
= (sb
->s_blocksize_bits
+ 2) * sizeof(*sbi
->s_mb_offsets
);
2413 sbi
->s_mb_offsets
= kmalloc(i
, GFP_KERNEL
);
2414 if (sbi
->s_mb_offsets
== NULL
) {
2418 i
= (sb
->s_blocksize_bits
+ 2) * sizeof(*sbi
->s_mb_maxs
);
2419 sbi
->s_mb_maxs
= kmalloc(i
, GFP_KERNEL
);
2420 if (sbi
->s_mb_maxs
== NULL
) {
2421 kfree(sbi
->s_mb_offsets
);
2425 /* order 0 is regular bitmap */
2426 sbi
->s_mb_maxs
[0] = sb
->s_blocksize
<< 3;
2427 sbi
->s_mb_offsets
[0] = 0;
2431 max
= sb
->s_blocksize
<< 2;
2433 sbi
->s_mb_offsets
[i
] = offset
;
2434 sbi
->s_mb_maxs
[i
] = max
;
2435 offset
+= 1 << (sb
->s_blocksize_bits
- i
);
2438 } while (i
<= sb
->s_blocksize_bits
+ 1);
2440 /* init file for buddy data */
2441 ret
= ext4_mb_init_backend(sb
);
2443 kfree(sbi
->s_mb_offsets
);
2444 kfree(sbi
->s_mb_maxs
);
2448 spin_lock_init(&sbi
->s_md_lock
);
2449 spin_lock_init(&sbi
->s_bal_lock
);
2451 sbi
->s_mb_max_to_scan
= MB_DEFAULT_MAX_TO_SCAN
;
2452 sbi
->s_mb_min_to_scan
= MB_DEFAULT_MIN_TO_SCAN
;
2453 sbi
->s_mb_stats
= MB_DEFAULT_STATS
;
2454 sbi
->s_mb_stream_request
= MB_DEFAULT_STREAM_THRESHOLD
;
2455 sbi
->s_mb_order2_reqs
= MB_DEFAULT_ORDER2_REQS
;
2456 sbi
->s_mb_group_prealloc
= MB_DEFAULT_GROUP_PREALLOC
;
2458 sbi
->s_locality_groups
= alloc_percpu(struct ext4_locality_group
);
2459 if (sbi
->s_locality_groups
== NULL
) {
2460 kfree(sbi
->s_mb_offsets
);
2461 kfree(sbi
->s_mb_maxs
);
2464 for_each_possible_cpu(i
) {
2465 struct ext4_locality_group
*lg
;
2466 lg
= per_cpu_ptr(sbi
->s_locality_groups
, i
);
2467 mutex_init(&lg
->lg_mutex
);
2468 for (j
= 0; j
< PREALLOC_TB_SIZE
; j
++)
2469 INIT_LIST_HEAD(&lg
->lg_prealloc_list
[j
]);
2470 spin_lock_init(&lg
->lg_prealloc_lock
);
2474 proc_create_data("mb_groups", S_IRUGO
, sbi
->s_proc
,
2475 &ext4_mb_seq_groups_fops
, sb
);
2478 sbi
->s_journal
->j_commit_callback
= release_blocks_on_commit
;
2482 /* need to called with the ext4 group lock held */
2483 static void ext4_mb_cleanup_pa(struct ext4_group_info
*grp
)
2485 struct ext4_prealloc_space
*pa
;
2486 struct list_head
*cur
, *tmp
;
2489 list_for_each_safe(cur
, tmp
, &grp
->bb_prealloc_list
) {
2490 pa
= list_entry(cur
, struct ext4_prealloc_space
, pa_group_list
);
2491 list_del(&pa
->pa_group_list
);
2493 kmem_cache_free(ext4_pspace_cachep
, pa
);
2496 mb_debug(1, "mballoc: %u PAs left\n", count
);
2500 int ext4_mb_release(struct super_block
*sb
)
2502 ext4_group_t ngroups
= ext4_get_groups_count(sb
);
2504 int num_meta_group_infos
;
2505 struct ext4_group_info
*grinfo
;
2506 struct ext4_sb_info
*sbi
= EXT4_SB(sb
);
2508 if (sbi
->s_group_info
) {
2509 for (i
= 0; i
< ngroups
; i
++) {
2510 grinfo
= ext4_get_group_info(sb
, i
);
2512 kfree(grinfo
->bb_bitmap
);
2514 ext4_lock_group(sb
, i
);
2515 ext4_mb_cleanup_pa(grinfo
);
2516 ext4_unlock_group(sb
, i
);
2519 num_meta_group_infos
= (ngroups
+
2520 EXT4_DESC_PER_BLOCK(sb
) - 1) >>
2521 EXT4_DESC_PER_BLOCK_BITS(sb
);
2522 for (i
= 0; i
< num_meta_group_infos
; i
++)
2523 kfree(sbi
->s_group_info
[i
]);
2524 kfree(sbi
->s_group_info
);
2526 kfree(sbi
->s_mb_offsets
);
2527 kfree(sbi
->s_mb_maxs
);
2528 if (sbi
->s_buddy_cache
)
2529 iput(sbi
->s_buddy_cache
);
2530 if (sbi
->s_mb_stats
) {
2532 "EXT4-fs: mballoc: %u blocks %u reqs (%u success)\n",
2533 atomic_read(&sbi
->s_bal_allocated
),
2534 atomic_read(&sbi
->s_bal_reqs
),
2535 atomic_read(&sbi
->s_bal_success
));
2537 "EXT4-fs: mballoc: %u extents scanned, %u goal hits, "
2538 "%u 2^N hits, %u breaks, %u lost\n",
2539 atomic_read(&sbi
->s_bal_ex_scanned
),
2540 atomic_read(&sbi
->s_bal_goals
),
2541 atomic_read(&sbi
->s_bal_2orders
),
2542 atomic_read(&sbi
->s_bal_breaks
),
2543 atomic_read(&sbi
->s_mb_lost_chunks
));
2545 "EXT4-fs: mballoc: %lu generated and it took %Lu\n",
2546 sbi
->s_mb_buddies_generated
++,
2547 sbi
->s_mb_generation_time
);
2549 "EXT4-fs: mballoc: %u preallocated, %u discarded\n",
2550 atomic_read(&sbi
->s_mb_preallocated
),
2551 atomic_read(&sbi
->s_mb_discarded
));
2554 free_percpu(sbi
->s_locality_groups
);
2556 remove_proc_entry("mb_groups", sbi
->s_proc
);
2561 static inline void ext4_issue_discard(struct super_block
*sb
,
2562 ext4_group_t block_group
, ext4_grpblk_t block
, int count
)
2565 ext4_fsblk_t discard_block
;
2567 discard_block
= block
+ ext4_group_first_block_no(sb
, block_group
);
2568 trace_ext4_discard_blocks(sb
,
2569 (unsigned long long) discard_block
, count
);
2570 ret
= sb_issue_discard(sb
, discard_block
, count
);
2571 if (ret
== EOPNOTSUPP
) {
2572 ext4_warning(sb
, "discard not supported, disabling");
2573 clear_opt(EXT4_SB(sb
)->s_mount_opt
, DISCARD
);
2578 * This function is called by the jbd2 layer once the commit has finished,
2579 * so we know we can free the blocks that were released with that commit.
2581 static void release_blocks_on_commit(journal_t
*journal
, transaction_t
*txn
)
2583 struct super_block
*sb
= journal
->j_private
;
2584 struct ext4_buddy e4b
;
2585 struct ext4_group_info
*db
;
2586 int err
, count
= 0, count2
= 0;
2587 struct ext4_free_data
*entry
;
2588 struct list_head
*l
, *ltmp
;
2590 list_for_each_safe(l
, ltmp
, &txn
->t_private_list
) {
2591 entry
= list_entry(l
, struct ext4_free_data
, list
);
2593 mb_debug(1, "gonna free %u blocks in group %u (0x%p):",
2594 entry
->count
, entry
->group
, entry
);
2596 if (test_opt(sb
, DISCARD
))
2597 ext4_issue_discard(sb
, entry
->group
,
2598 entry
->start_blk
, entry
->count
);
2600 err
= ext4_mb_load_buddy(sb
, entry
->group
, &e4b
);
2601 /* we expect to find existing buddy because it's pinned */
2605 /* there are blocks to put in buddy to make them really free */
2606 count
+= entry
->count
;
2608 ext4_lock_group(sb
, entry
->group
);
2609 /* Take it out of per group rb tree */
2610 rb_erase(&entry
->node
, &(db
->bb_free_root
));
2611 mb_free_blocks(NULL
, &e4b
, entry
->start_blk
, entry
->count
);
2613 if (!db
->bb_free_root
.rb_node
) {
2614 /* No more items in the per group rb tree
2615 * balance refcounts from ext4_mb_free_metadata()
2617 page_cache_release(e4b
.bd_buddy_page
);
2618 page_cache_release(e4b
.bd_bitmap_page
);
2620 ext4_unlock_group(sb
, entry
->group
);
2621 kmem_cache_free(ext4_free_ext_cachep
, entry
);
2622 ext4_mb_unload_buddy(&e4b
);
2625 mb_debug(1, "freed %u blocks in %u structures\n", count
, count2
);
2628 #ifdef CONFIG_EXT4_DEBUG
2629 u8 mb_enable_debug __read_mostly
;
2631 static struct dentry
*debugfs_dir
;
2632 static struct dentry
*debugfs_debug
;
2634 static void __init
ext4_create_debugfs_entry(void)
2636 debugfs_dir
= debugfs_create_dir("ext4", NULL
);
2638 debugfs_debug
= debugfs_create_u8("mballoc-debug",
2644 static void ext4_remove_debugfs_entry(void)
2646 debugfs_remove(debugfs_debug
);
2647 debugfs_remove(debugfs_dir
);
2652 static void __init
ext4_create_debugfs_entry(void)
2656 static void ext4_remove_debugfs_entry(void)
2662 int __init
init_ext4_mballoc(void)
2664 ext4_pspace_cachep
=
2665 kmem_cache_create("ext4_prealloc_space",
2666 sizeof(struct ext4_prealloc_space
),
2667 0, SLAB_RECLAIM_ACCOUNT
, NULL
);
2668 if (ext4_pspace_cachep
== NULL
)
2672 kmem_cache_create("ext4_alloc_context",
2673 sizeof(struct ext4_allocation_context
),
2674 0, SLAB_RECLAIM_ACCOUNT
, NULL
);
2675 if (ext4_ac_cachep
== NULL
) {
2676 kmem_cache_destroy(ext4_pspace_cachep
);
2680 ext4_free_ext_cachep
=
2681 kmem_cache_create("ext4_free_block_extents",
2682 sizeof(struct ext4_free_data
),
2683 0, SLAB_RECLAIM_ACCOUNT
, NULL
);
2684 if (ext4_free_ext_cachep
== NULL
) {
2685 kmem_cache_destroy(ext4_pspace_cachep
);
2686 kmem_cache_destroy(ext4_ac_cachep
);
2689 ext4_create_debugfs_entry();
2693 void exit_ext4_mballoc(void)
2696 * Wait for completion of call_rcu()'s on ext4_pspace_cachep
2697 * before destroying the slab cache.
2700 kmem_cache_destroy(ext4_pspace_cachep
);
2701 kmem_cache_destroy(ext4_ac_cachep
);
2702 kmem_cache_destroy(ext4_free_ext_cachep
);
2703 ext4_remove_debugfs_entry();
2708 * Check quota and mark choosed space (ac->ac_b_ex) non-free in bitmaps
2709 * Returns 0 if success or error code
2711 static noinline_for_stack
int
2712 ext4_mb_mark_diskspace_used(struct ext4_allocation_context
*ac
,
2713 handle_t
*handle
, unsigned int reserv_blks
)
2715 struct buffer_head
*bitmap_bh
= NULL
;
2716 struct ext4_group_desc
*gdp
;
2717 struct buffer_head
*gdp_bh
;
2718 struct ext4_sb_info
*sbi
;
2719 struct super_block
*sb
;
2723 BUG_ON(ac
->ac_status
!= AC_STATUS_FOUND
);
2724 BUG_ON(ac
->ac_b_ex
.fe_len
<= 0);
2730 bitmap_bh
= ext4_read_block_bitmap(sb
, ac
->ac_b_ex
.fe_group
);
2734 err
= ext4_journal_get_write_access(handle
, bitmap_bh
);
2739 gdp
= ext4_get_group_desc(sb
, ac
->ac_b_ex
.fe_group
, &gdp_bh
);
2743 ext4_debug("using block group %u(%d)\n", ac
->ac_b_ex
.fe_group
,
2744 ext4_free_blks_count(sb
, gdp
));
2746 err
= ext4_journal_get_write_access(handle
, gdp_bh
);
2750 block
= ext4_grp_offs_to_block(sb
, &ac
->ac_b_ex
);
2752 len
= ac
->ac_b_ex
.fe_len
;
2753 if (!ext4_data_block_valid(sbi
, block
, len
)) {
2754 ext4_error(sb
, "Allocating blocks %llu-%llu which overlap "
2755 "fs metadata\n", block
, block
+len
);
2756 /* File system mounted not to panic on error
2757 * Fix the bitmap and repeat the block allocation
2758 * We leak some of the blocks here.
2760 ext4_lock_group(sb
, ac
->ac_b_ex
.fe_group
);
2761 mb_set_bits(bitmap_bh
->b_data
, ac
->ac_b_ex
.fe_start
,
2762 ac
->ac_b_ex
.fe_len
);
2763 ext4_unlock_group(sb
, ac
->ac_b_ex
.fe_group
);
2764 err
= ext4_handle_dirty_metadata(handle
, NULL
, bitmap_bh
);
2770 ext4_lock_group(sb
, ac
->ac_b_ex
.fe_group
);
2771 #ifdef AGGRESSIVE_CHECK
2774 for (i
= 0; i
< ac
->ac_b_ex
.fe_len
; i
++) {
2775 BUG_ON(mb_test_bit(ac
->ac_b_ex
.fe_start
+ i
,
2776 bitmap_bh
->b_data
));
2780 mb_set_bits(bitmap_bh
->b_data
, ac
->ac_b_ex
.fe_start
,ac
->ac_b_ex
.fe_len
);
2781 if (gdp
->bg_flags
& cpu_to_le16(EXT4_BG_BLOCK_UNINIT
)) {
2782 gdp
->bg_flags
&= cpu_to_le16(~EXT4_BG_BLOCK_UNINIT
);
2783 ext4_free_blks_set(sb
, gdp
,
2784 ext4_free_blocks_after_init(sb
,
2785 ac
->ac_b_ex
.fe_group
, gdp
));
2787 len
= ext4_free_blks_count(sb
, gdp
) - ac
->ac_b_ex
.fe_len
;
2788 ext4_free_blks_set(sb
, gdp
, len
);
2789 gdp
->bg_checksum
= ext4_group_desc_csum(sbi
, ac
->ac_b_ex
.fe_group
, gdp
);
2791 ext4_unlock_group(sb
, ac
->ac_b_ex
.fe_group
);
2792 percpu_counter_sub(&sbi
->s_freeblocks_counter
, ac
->ac_b_ex
.fe_len
);
2794 * Now reduce the dirty block count also. Should not go negative
2796 if (!(ac
->ac_flags
& EXT4_MB_DELALLOC_RESERVED
))
2797 /* release all the reserved blocks if non delalloc */
2798 percpu_counter_sub(&sbi
->s_dirtyblocks_counter
, reserv_blks
);
2800 if (sbi
->s_log_groups_per_flex
) {
2801 ext4_group_t flex_group
= ext4_flex_group(sbi
,
2802 ac
->ac_b_ex
.fe_group
);
2803 atomic_sub(ac
->ac_b_ex
.fe_len
,
2804 &sbi
->s_flex_groups
[flex_group
].free_blocks
);
2807 err
= ext4_handle_dirty_metadata(handle
, NULL
, bitmap_bh
);
2810 err
= ext4_handle_dirty_metadata(handle
, NULL
, gdp_bh
);
2813 ext4_mark_super_dirty(sb
);
2819 * here we normalize request for locality group
2820 * Group request are normalized to s_strip size if we set the same via mount
2821 * option. If not we set it to s_mb_group_prealloc which can be configured via
2822 * /sys/fs/ext4/<partition>/mb_group_prealloc
2824 * XXX: should we try to preallocate more than the group has now?
2826 static void ext4_mb_normalize_group_request(struct ext4_allocation_context
*ac
)
2828 struct super_block
*sb
= ac
->ac_sb
;
2829 struct ext4_locality_group
*lg
= ac
->ac_lg
;
2832 if (EXT4_SB(sb
)->s_stripe
)
2833 ac
->ac_g_ex
.fe_len
= EXT4_SB(sb
)->s_stripe
;
2835 ac
->ac_g_ex
.fe_len
= EXT4_SB(sb
)->s_mb_group_prealloc
;
2836 mb_debug(1, "#%u: goal %u blocks for locality group\n",
2837 current
->pid
, ac
->ac_g_ex
.fe_len
);
2841 * Normalization means making request better in terms of
2842 * size and alignment
2844 static noinline_for_stack
void
2845 ext4_mb_normalize_request(struct ext4_allocation_context
*ac
,
2846 struct ext4_allocation_request
*ar
)
2850 loff_t size
, orig_size
, start_off
;
2852 struct ext4_inode_info
*ei
= EXT4_I(ac
->ac_inode
);
2853 struct ext4_prealloc_space
*pa
;
2855 /* do normalize only data requests, metadata requests
2856 do not need preallocation */
2857 if (!(ac
->ac_flags
& EXT4_MB_HINT_DATA
))
2860 /* sometime caller may want exact blocks */
2861 if (unlikely(ac
->ac_flags
& EXT4_MB_HINT_GOAL_ONLY
))
2864 /* caller may indicate that preallocation isn't
2865 * required (it's a tail, for example) */
2866 if (ac
->ac_flags
& EXT4_MB_HINT_NOPREALLOC
)
2869 if (ac
->ac_flags
& EXT4_MB_HINT_GROUP_ALLOC
) {
2870 ext4_mb_normalize_group_request(ac
);
2874 bsbits
= ac
->ac_sb
->s_blocksize_bits
;
2876 /* first, let's learn actual file size
2877 * given current request is allocated */
2878 size
= ac
->ac_o_ex
.fe_logical
+ ac
->ac_o_ex
.fe_len
;
2879 size
= size
<< bsbits
;
2880 if (size
< i_size_read(ac
->ac_inode
))
2881 size
= i_size_read(ac
->ac_inode
);
2884 /* max size of free chunks */
2887 #define NRL_CHECK_SIZE(req, size, max, chunk_size) \
2888 (req <= (size) || max <= (chunk_size))
2890 /* first, try to predict filesize */
2891 /* XXX: should this table be tunable? */
2893 if (size
<= 16 * 1024) {
2895 } else if (size
<= 32 * 1024) {
2897 } else if (size
<= 64 * 1024) {
2899 } else if (size
<= 128 * 1024) {
2901 } else if (size
<= 256 * 1024) {
2903 } else if (size
<= 512 * 1024) {
2905 } else if (size
<= 1024 * 1024) {
2907 } else if (NRL_CHECK_SIZE(size
, 4 * 1024 * 1024, max
, 2 * 1024)) {
2908 start_off
= ((loff_t
)ac
->ac_o_ex
.fe_logical
>>
2909 (21 - bsbits
)) << 21;
2910 size
= 2 * 1024 * 1024;
2911 } else if (NRL_CHECK_SIZE(size
, 8 * 1024 * 1024, max
, 4 * 1024)) {
2912 start_off
= ((loff_t
)ac
->ac_o_ex
.fe_logical
>>
2913 (22 - bsbits
)) << 22;
2914 size
= 4 * 1024 * 1024;
2915 } else if (NRL_CHECK_SIZE(ac
->ac_o_ex
.fe_len
,
2916 (8<<20)>>bsbits
, max
, 8 * 1024)) {
2917 start_off
= ((loff_t
)ac
->ac_o_ex
.fe_logical
>>
2918 (23 - bsbits
)) << 23;
2919 size
= 8 * 1024 * 1024;
2921 start_off
= (loff_t
)ac
->ac_o_ex
.fe_logical
<< bsbits
;
2922 size
= ac
->ac_o_ex
.fe_len
<< bsbits
;
2924 size
= size
>> bsbits
;
2925 start
= start_off
>> bsbits
;
2927 /* don't cover already allocated blocks in selected range */
2928 if (ar
->pleft
&& start
<= ar
->lleft
) {
2929 size
-= ar
->lleft
+ 1 - start
;
2930 start
= ar
->lleft
+ 1;
2932 if (ar
->pright
&& start
+ size
- 1 >= ar
->lright
)
2933 size
-= start
+ size
- ar
->lright
;
2937 /* check we don't cross already preallocated blocks */
2939 list_for_each_entry_rcu(pa
, &ei
->i_prealloc_list
, pa_inode_list
) {
2944 spin_lock(&pa
->pa_lock
);
2945 if (pa
->pa_deleted
) {
2946 spin_unlock(&pa
->pa_lock
);
2950 pa_end
= pa
->pa_lstart
+ pa
->pa_len
;
2952 /* PA must not overlap original request */
2953 BUG_ON(!(ac
->ac_o_ex
.fe_logical
>= pa_end
||
2954 ac
->ac_o_ex
.fe_logical
< pa
->pa_lstart
));
2956 /* skip PAs this normalized request doesn't overlap with */
2957 if (pa
->pa_lstart
>= end
|| pa_end
<= start
) {
2958 spin_unlock(&pa
->pa_lock
);
2961 BUG_ON(pa
->pa_lstart
<= start
&& pa_end
>= end
);
2963 /* adjust start or end to be adjacent to this pa */
2964 if (pa_end
<= ac
->ac_o_ex
.fe_logical
) {
2965 BUG_ON(pa_end
< start
);
2967 } else if (pa
->pa_lstart
> ac
->ac_o_ex
.fe_logical
) {
2968 BUG_ON(pa
->pa_lstart
> end
);
2969 end
= pa
->pa_lstart
;
2971 spin_unlock(&pa
->pa_lock
);
2976 /* XXX: extra loop to check we really don't overlap preallocations */
2978 list_for_each_entry_rcu(pa
, &ei
->i_prealloc_list
, pa_inode_list
) {
2980 spin_lock(&pa
->pa_lock
);
2981 if (pa
->pa_deleted
== 0) {
2982 pa_end
= pa
->pa_lstart
+ pa
->pa_len
;
2983 BUG_ON(!(start
>= pa_end
|| end
<= pa
->pa_lstart
));
2985 spin_unlock(&pa
->pa_lock
);
2989 if (start
+ size
<= ac
->ac_o_ex
.fe_logical
&&
2990 start
> ac
->ac_o_ex
.fe_logical
) {
2991 printk(KERN_ERR
"start %lu, size %lu, fe_logical %lu\n",
2992 (unsigned long) start
, (unsigned long) size
,
2993 (unsigned long) ac
->ac_o_ex
.fe_logical
);
2995 BUG_ON(start
+ size
<= ac
->ac_o_ex
.fe_logical
&&
2996 start
> ac
->ac_o_ex
.fe_logical
);
2997 BUG_ON(size
<= 0 || size
> EXT4_BLOCKS_PER_GROUP(ac
->ac_sb
));
2999 /* now prepare goal request */
3001 /* XXX: is it better to align blocks WRT to logical
3002 * placement or satisfy big request as is */
3003 ac
->ac_g_ex
.fe_logical
= start
;
3004 ac
->ac_g_ex
.fe_len
= size
;
3006 /* define goal start in order to merge */
3007 if (ar
->pright
&& (ar
->lright
== (start
+ size
))) {
3008 /* merge to the right */
3009 ext4_get_group_no_and_offset(ac
->ac_sb
, ar
->pright
- size
,
3010 &ac
->ac_f_ex
.fe_group
,
3011 &ac
->ac_f_ex
.fe_start
);
3012 ac
->ac_flags
|= EXT4_MB_HINT_TRY_GOAL
;
3014 if (ar
->pleft
&& (ar
->lleft
+ 1 == start
)) {
3015 /* merge to the left */
3016 ext4_get_group_no_and_offset(ac
->ac_sb
, ar
->pleft
+ 1,
3017 &ac
->ac_f_ex
.fe_group
,
3018 &ac
->ac_f_ex
.fe_start
);
3019 ac
->ac_flags
|= EXT4_MB_HINT_TRY_GOAL
;
3022 mb_debug(1, "goal: %u(was %u) blocks at %u\n", (unsigned) size
,
3023 (unsigned) orig_size
, (unsigned) start
);
3026 static void ext4_mb_collect_stats(struct ext4_allocation_context
*ac
)
3028 struct ext4_sb_info
*sbi
= EXT4_SB(ac
->ac_sb
);
3030 if (sbi
->s_mb_stats
&& ac
->ac_g_ex
.fe_len
> 1) {
3031 atomic_inc(&sbi
->s_bal_reqs
);
3032 atomic_add(ac
->ac_b_ex
.fe_len
, &sbi
->s_bal_allocated
);
3033 if (ac
->ac_b_ex
.fe_len
>= ac
->ac_o_ex
.fe_len
)
3034 atomic_inc(&sbi
->s_bal_success
);
3035 atomic_add(ac
->ac_found
, &sbi
->s_bal_ex_scanned
);
3036 if (ac
->ac_g_ex
.fe_start
== ac
->ac_b_ex
.fe_start
&&
3037 ac
->ac_g_ex
.fe_group
== ac
->ac_b_ex
.fe_group
)
3038 atomic_inc(&sbi
->s_bal_goals
);
3039 if (ac
->ac_found
> sbi
->s_mb_max_to_scan
)
3040 atomic_inc(&sbi
->s_bal_breaks
);
3043 if (ac
->ac_op
== EXT4_MB_HISTORY_ALLOC
)
3044 trace_ext4_mballoc_alloc(ac
);
3046 trace_ext4_mballoc_prealloc(ac
);
3050 * Called on failure; free up any blocks from the inode PA for this
3051 * context. We don't need this for MB_GROUP_PA because we only change
3052 * pa_free in ext4_mb_release_context(), but on failure, we've already
3053 * zeroed out ac->ac_b_ex.fe_len, so group_pa->pa_free is not changed.
3055 static void ext4_discard_allocated_blocks(struct ext4_allocation_context
*ac
)
3057 struct ext4_prealloc_space
*pa
= ac
->ac_pa
;
3060 if (pa
&& pa
->pa_type
== MB_INODE_PA
) {
3061 len
= ac
->ac_b_ex
.fe_len
;
3068 * use blocks preallocated to inode
3070 static void ext4_mb_use_inode_pa(struct ext4_allocation_context
*ac
,
3071 struct ext4_prealloc_space
*pa
)
3077 /* found preallocated blocks, use them */
3078 start
= pa
->pa_pstart
+ (ac
->ac_o_ex
.fe_logical
- pa
->pa_lstart
);
3079 end
= min(pa
->pa_pstart
+ pa
->pa_len
, start
+ ac
->ac_o_ex
.fe_len
);
3081 ext4_get_group_no_and_offset(ac
->ac_sb
, start
, &ac
->ac_b_ex
.fe_group
,
3082 &ac
->ac_b_ex
.fe_start
);
3083 ac
->ac_b_ex
.fe_len
= len
;
3084 ac
->ac_status
= AC_STATUS_FOUND
;
3087 BUG_ON(start
< pa
->pa_pstart
);
3088 BUG_ON(start
+ len
> pa
->pa_pstart
+ pa
->pa_len
);
3089 BUG_ON(pa
->pa_free
< len
);
3092 mb_debug(1, "use %llu/%u from inode pa %p\n", start
, len
, pa
);
3096 * use blocks preallocated to locality group
3098 static void ext4_mb_use_group_pa(struct ext4_allocation_context
*ac
,
3099 struct ext4_prealloc_space
*pa
)
3101 unsigned int len
= ac
->ac_o_ex
.fe_len
;
3103 ext4_get_group_no_and_offset(ac
->ac_sb
, pa
->pa_pstart
,
3104 &ac
->ac_b_ex
.fe_group
,
3105 &ac
->ac_b_ex
.fe_start
);
3106 ac
->ac_b_ex
.fe_len
= len
;
3107 ac
->ac_status
= AC_STATUS_FOUND
;
3110 /* we don't correct pa_pstart or pa_plen here to avoid
3111 * possible race when the group is being loaded concurrently
3112 * instead we correct pa later, after blocks are marked
3113 * in on-disk bitmap -- see ext4_mb_release_context()
3114 * Other CPUs are prevented from allocating from this pa by lg_mutex
3116 mb_debug(1, "use %u/%u from group pa %p\n", pa
->pa_lstart
-len
, len
, pa
);
3120 * Return the prealloc space that have minimal distance
3121 * from the goal block. @cpa is the prealloc
3122 * space that is having currently known minimal distance
3123 * from the goal block.
3125 static struct ext4_prealloc_space
*
3126 ext4_mb_check_group_pa(ext4_fsblk_t goal_block
,
3127 struct ext4_prealloc_space
*pa
,
3128 struct ext4_prealloc_space
*cpa
)
3130 ext4_fsblk_t cur_distance
, new_distance
;
3133 atomic_inc(&pa
->pa_count
);
3136 cur_distance
= abs(goal_block
- cpa
->pa_pstart
);
3137 new_distance
= abs(goal_block
- pa
->pa_pstart
);
3139 if (cur_distance
< new_distance
)
3142 /* drop the previous reference */
3143 atomic_dec(&cpa
->pa_count
);
3144 atomic_inc(&pa
->pa_count
);
3149 * search goal blocks in preallocated space
3151 static noinline_for_stack
int
3152 ext4_mb_use_preallocated(struct ext4_allocation_context
*ac
)
3155 struct ext4_inode_info
*ei
= EXT4_I(ac
->ac_inode
);
3156 struct ext4_locality_group
*lg
;
3157 struct ext4_prealloc_space
*pa
, *cpa
= NULL
;
3158 ext4_fsblk_t goal_block
;
3160 /* only data can be preallocated */
3161 if (!(ac
->ac_flags
& EXT4_MB_HINT_DATA
))
3164 /* first, try per-file preallocation */
3166 list_for_each_entry_rcu(pa
, &ei
->i_prealloc_list
, pa_inode_list
) {
3168 /* all fields in this condition don't change,
3169 * so we can skip locking for them */
3170 if (ac
->ac_o_ex
.fe_logical
< pa
->pa_lstart
||
3171 ac
->ac_o_ex
.fe_logical
>= pa
->pa_lstart
+ pa
->pa_len
)
3174 /* non-extent files can't have physical blocks past 2^32 */
3175 if (!(ext4_test_inode_flag(ac
->ac_inode
, EXT4_INODE_EXTENTS
)) &&
3176 pa
->pa_pstart
+ pa
->pa_len
> EXT4_MAX_BLOCK_FILE_PHYS
)
3179 /* found preallocated blocks, use them */
3180 spin_lock(&pa
->pa_lock
);
3181 if (pa
->pa_deleted
== 0 && pa
->pa_free
) {
3182 atomic_inc(&pa
->pa_count
);
3183 ext4_mb_use_inode_pa(ac
, pa
);
3184 spin_unlock(&pa
->pa_lock
);
3185 ac
->ac_criteria
= 10;
3189 spin_unlock(&pa
->pa_lock
);
3193 /* can we use group allocation? */
3194 if (!(ac
->ac_flags
& EXT4_MB_HINT_GROUP_ALLOC
))
3197 /* inode may have no locality group for some reason */
3201 order
= fls(ac
->ac_o_ex
.fe_len
) - 1;
3202 if (order
> PREALLOC_TB_SIZE
- 1)
3203 /* The max size of hash table is PREALLOC_TB_SIZE */
3204 order
= PREALLOC_TB_SIZE
- 1;
3206 goal_block
= ext4_grp_offs_to_block(ac
->ac_sb
, &ac
->ac_g_ex
);
3208 * search for the prealloc space that is having
3209 * minimal distance from the goal block.
3211 for (i
= order
; i
< PREALLOC_TB_SIZE
; i
++) {
3213 list_for_each_entry_rcu(pa
, &lg
->lg_prealloc_list
[i
],
3215 spin_lock(&pa
->pa_lock
);
3216 if (pa
->pa_deleted
== 0 &&
3217 pa
->pa_free
>= ac
->ac_o_ex
.fe_len
) {
3219 cpa
= ext4_mb_check_group_pa(goal_block
,
3222 spin_unlock(&pa
->pa_lock
);
3227 ext4_mb_use_group_pa(ac
, cpa
);
3228 ac
->ac_criteria
= 20;
3235 * the function goes through all block freed in the group
3236 * but not yet committed and marks them used in in-core bitmap.
3237 * buddy must be generated from this bitmap
3238 * Need to be called with the ext4 group lock held
3240 static void ext4_mb_generate_from_freelist(struct super_block
*sb
, void *bitmap
,
3244 struct ext4_group_info
*grp
;
3245 struct ext4_free_data
*entry
;
3247 grp
= ext4_get_group_info(sb
, group
);
3248 n
= rb_first(&(grp
->bb_free_root
));
3251 entry
= rb_entry(n
, struct ext4_free_data
, node
);
3252 mb_set_bits(bitmap
, entry
->start_blk
, entry
->count
);
3259 * the function goes through all preallocation in this group and marks them
3260 * used in in-core bitmap. buddy must be generated from this bitmap
3261 * Need to be called with ext4 group lock held
3263 static noinline_for_stack
3264 void ext4_mb_generate_from_pa(struct super_block
*sb
, void *bitmap
,
3267 struct ext4_group_info
*grp
= ext4_get_group_info(sb
, group
);
3268 struct ext4_prealloc_space
*pa
;
3269 struct list_head
*cur
;
3270 ext4_group_t groupnr
;
3271 ext4_grpblk_t start
;
3272 int preallocated
= 0;
3276 /* all form of preallocation discards first load group,
3277 * so the only competing code is preallocation use.
3278 * we don't need any locking here
3279 * notice we do NOT ignore preallocations with pa_deleted
3280 * otherwise we could leave used blocks available for
3281 * allocation in buddy when concurrent ext4_mb_put_pa()
3282 * is dropping preallocation
3284 list_for_each(cur
, &grp
->bb_prealloc_list
) {
3285 pa
= list_entry(cur
, struct ext4_prealloc_space
, pa_group_list
);
3286 spin_lock(&pa
->pa_lock
);
3287 ext4_get_group_no_and_offset(sb
, pa
->pa_pstart
,
3290 spin_unlock(&pa
->pa_lock
);
3291 if (unlikely(len
== 0))
3293 BUG_ON(groupnr
!= group
);
3294 mb_set_bits(bitmap
, start
, len
);
3295 preallocated
+= len
;
3298 mb_debug(1, "prellocated %u for group %u\n", preallocated
, group
);
3301 static void ext4_mb_pa_callback(struct rcu_head
*head
)
3303 struct ext4_prealloc_space
*pa
;
3304 pa
= container_of(head
, struct ext4_prealloc_space
, u
.pa_rcu
);
3305 kmem_cache_free(ext4_pspace_cachep
, pa
);
3309 * drops a reference to preallocated space descriptor
3310 * if this was the last reference and the space is consumed
3312 static void ext4_mb_put_pa(struct ext4_allocation_context
*ac
,
3313 struct super_block
*sb
, struct ext4_prealloc_space
*pa
)
3316 ext4_fsblk_t grp_blk
;
3318 if (!atomic_dec_and_test(&pa
->pa_count
) || pa
->pa_free
!= 0)
3321 /* in this short window concurrent discard can set pa_deleted */
3322 spin_lock(&pa
->pa_lock
);
3323 if (pa
->pa_deleted
== 1) {
3324 spin_unlock(&pa
->pa_lock
);
3329 spin_unlock(&pa
->pa_lock
);
3331 grp_blk
= pa
->pa_pstart
;
3333 * If doing group-based preallocation, pa_pstart may be in the
3334 * next group when pa is used up
3336 if (pa
->pa_type
== MB_GROUP_PA
)
3339 ext4_get_group_no_and_offset(sb
, grp_blk
, &grp
, NULL
);
3344 * P1 (buddy init) P2 (regular allocation)
3345 * find block B in PA
3346 * copy on-disk bitmap to buddy
3347 * mark B in on-disk bitmap
3348 * drop PA from group
3349 * mark all PAs in buddy
3351 * thus, P1 initializes buddy with B available. to prevent this
3352 * we make "copy" and "mark all PAs" atomic and serialize "drop PA"
3355 ext4_lock_group(sb
, grp
);
3356 list_del(&pa
->pa_group_list
);
3357 ext4_unlock_group(sb
, grp
);
3359 spin_lock(pa
->pa_obj_lock
);
3360 list_del_rcu(&pa
->pa_inode_list
);
3361 spin_unlock(pa
->pa_obj_lock
);
3363 call_rcu(&(pa
)->u
.pa_rcu
, ext4_mb_pa_callback
);
3367 * creates new preallocated space for given inode
3369 static noinline_for_stack
int
3370 ext4_mb_new_inode_pa(struct ext4_allocation_context
*ac
)
3372 struct super_block
*sb
= ac
->ac_sb
;
3373 struct ext4_prealloc_space
*pa
;
3374 struct ext4_group_info
*grp
;
3375 struct ext4_inode_info
*ei
;
3377 /* preallocate only when found space is larger then requested */
3378 BUG_ON(ac
->ac_o_ex
.fe_len
>= ac
->ac_b_ex
.fe_len
);
3379 BUG_ON(ac
->ac_status
!= AC_STATUS_FOUND
);
3380 BUG_ON(!S_ISREG(ac
->ac_inode
->i_mode
));
3382 pa
= kmem_cache_alloc(ext4_pspace_cachep
, GFP_NOFS
);
3386 if (ac
->ac_b_ex
.fe_len
< ac
->ac_g_ex
.fe_len
) {
3392 /* we can't allocate as much as normalizer wants.
3393 * so, found space must get proper lstart
3394 * to cover original request */
3395 BUG_ON(ac
->ac_g_ex
.fe_logical
> ac
->ac_o_ex
.fe_logical
);
3396 BUG_ON(ac
->ac_g_ex
.fe_len
< ac
->ac_o_ex
.fe_len
);
3398 /* we're limited by original request in that
3399 * logical block must be covered any way
3400 * winl is window we can move our chunk within */
3401 winl
= ac
->ac_o_ex
.fe_logical
- ac
->ac_g_ex
.fe_logical
;
3403 /* also, we should cover whole original request */
3404 wins
= ac
->ac_b_ex
.fe_len
- ac
->ac_o_ex
.fe_len
;
3406 /* the smallest one defines real window */
3407 win
= min(winl
, wins
);
3409 offs
= ac
->ac_o_ex
.fe_logical
% ac
->ac_b_ex
.fe_len
;
3410 if (offs
&& offs
< win
)
3413 ac
->ac_b_ex
.fe_logical
= ac
->ac_o_ex
.fe_logical
- win
;
3414 BUG_ON(ac
->ac_o_ex
.fe_logical
< ac
->ac_b_ex
.fe_logical
);
3415 BUG_ON(ac
->ac_o_ex
.fe_len
> ac
->ac_b_ex
.fe_len
);
3418 /* preallocation can change ac_b_ex, thus we store actually
3419 * allocated blocks for history */
3420 ac
->ac_f_ex
= ac
->ac_b_ex
;
3422 pa
->pa_lstart
= ac
->ac_b_ex
.fe_logical
;
3423 pa
->pa_pstart
= ext4_grp_offs_to_block(sb
, &ac
->ac_b_ex
);
3424 pa
->pa_len
= ac
->ac_b_ex
.fe_len
;
3425 pa
->pa_free
= pa
->pa_len
;
3426 atomic_set(&pa
->pa_count
, 1);
3427 spin_lock_init(&pa
->pa_lock
);
3428 INIT_LIST_HEAD(&pa
->pa_inode_list
);
3429 INIT_LIST_HEAD(&pa
->pa_group_list
);
3431 pa
->pa_type
= MB_INODE_PA
;
3433 mb_debug(1, "new inode pa %p: %llu/%u for %u\n", pa
,
3434 pa
->pa_pstart
, pa
->pa_len
, pa
->pa_lstart
);
3435 trace_ext4_mb_new_inode_pa(ac
, pa
);
3437 ext4_mb_use_inode_pa(ac
, pa
);
3438 atomic_add(pa
->pa_free
, &EXT4_SB(sb
)->s_mb_preallocated
);
3440 ei
= EXT4_I(ac
->ac_inode
);
3441 grp
= ext4_get_group_info(sb
, ac
->ac_b_ex
.fe_group
);
3443 pa
->pa_obj_lock
= &ei
->i_prealloc_lock
;
3444 pa
->pa_inode
= ac
->ac_inode
;
3446 ext4_lock_group(sb
, ac
->ac_b_ex
.fe_group
);
3447 list_add(&pa
->pa_group_list
, &grp
->bb_prealloc_list
);
3448 ext4_unlock_group(sb
, ac
->ac_b_ex
.fe_group
);
3450 spin_lock(pa
->pa_obj_lock
);
3451 list_add_rcu(&pa
->pa_inode_list
, &ei
->i_prealloc_list
);
3452 spin_unlock(pa
->pa_obj_lock
);
3458 * creates new preallocated space for locality group inodes belongs to
3460 static noinline_for_stack
int
3461 ext4_mb_new_group_pa(struct ext4_allocation_context
*ac
)
3463 struct super_block
*sb
= ac
->ac_sb
;
3464 struct ext4_locality_group
*lg
;
3465 struct ext4_prealloc_space
*pa
;
3466 struct ext4_group_info
*grp
;
3468 /* preallocate only when found space is larger then requested */
3469 BUG_ON(ac
->ac_o_ex
.fe_len
>= ac
->ac_b_ex
.fe_len
);
3470 BUG_ON(ac
->ac_status
!= AC_STATUS_FOUND
);
3471 BUG_ON(!S_ISREG(ac
->ac_inode
->i_mode
));
3473 BUG_ON(ext4_pspace_cachep
== NULL
);
3474 pa
= kmem_cache_alloc(ext4_pspace_cachep
, GFP_NOFS
);
3478 /* preallocation can change ac_b_ex, thus we store actually
3479 * allocated blocks for history */
3480 ac
->ac_f_ex
= ac
->ac_b_ex
;
3482 pa
->pa_pstart
= ext4_grp_offs_to_block(sb
, &ac
->ac_b_ex
);
3483 pa
->pa_lstart
= pa
->pa_pstart
;
3484 pa
->pa_len
= ac
->ac_b_ex
.fe_len
;
3485 pa
->pa_free
= pa
->pa_len
;
3486 atomic_set(&pa
->pa_count
, 1);
3487 spin_lock_init(&pa
->pa_lock
);
3488 INIT_LIST_HEAD(&pa
->pa_inode_list
);
3489 INIT_LIST_HEAD(&pa
->pa_group_list
);
3491 pa
->pa_type
= MB_GROUP_PA
;
3493 mb_debug(1, "new group pa %p: %llu/%u for %u\n", pa
,
3494 pa
->pa_pstart
, pa
->pa_len
, pa
->pa_lstart
);
3495 trace_ext4_mb_new_group_pa(ac
, pa
);
3497 ext4_mb_use_group_pa(ac
, pa
);
3498 atomic_add(pa
->pa_free
, &EXT4_SB(sb
)->s_mb_preallocated
);
3500 grp
= ext4_get_group_info(sb
, ac
->ac_b_ex
.fe_group
);
3504 pa
->pa_obj_lock
= &lg
->lg_prealloc_lock
;
3505 pa
->pa_inode
= NULL
;
3507 ext4_lock_group(sb
, ac
->ac_b_ex
.fe_group
);
3508 list_add(&pa
->pa_group_list
, &grp
->bb_prealloc_list
);
3509 ext4_unlock_group(sb
, ac
->ac_b_ex
.fe_group
);
3512 * We will later add the new pa to the right bucket
3513 * after updating the pa_free in ext4_mb_release_context
3518 static int ext4_mb_new_preallocation(struct ext4_allocation_context
*ac
)
3522 if (ac
->ac_flags
& EXT4_MB_HINT_GROUP_ALLOC
)
3523 err
= ext4_mb_new_group_pa(ac
);
3525 err
= ext4_mb_new_inode_pa(ac
);
3530 * finds all unused blocks in on-disk bitmap, frees them in
3531 * in-core bitmap and buddy.
3532 * @pa must be unlinked from inode and group lists, so that
3533 * nobody else can find/use it.
3534 * the caller MUST hold group/inode locks.
3535 * TODO: optimize the case when there are no in-core structures yet
3537 static noinline_for_stack
int
3538 ext4_mb_release_inode_pa(struct ext4_buddy
*e4b
, struct buffer_head
*bitmap_bh
,
3539 struct ext4_prealloc_space
*pa
,
3540 struct ext4_allocation_context
*ac
)
3542 struct super_block
*sb
= e4b
->bd_sb
;
3543 struct ext4_sb_info
*sbi
= EXT4_SB(sb
);
3548 unsigned long long grp_blk_start
;
3552 BUG_ON(pa
->pa_deleted
== 0);
3553 ext4_get_group_no_and_offset(sb
, pa
->pa_pstart
, &group
, &bit
);
3554 grp_blk_start
= pa
->pa_pstart
- bit
;
3555 BUG_ON(group
!= e4b
->bd_group
&& pa
->pa_len
!= 0);
3556 end
= bit
+ pa
->pa_len
;
3560 ac
->ac_inode
= pa
->pa_inode
;
3564 bit
= mb_find_next_zero_bit(bitmap_bh
->b_data
, end
, bit
);
3567 next
= mb_find_next_bit(bitmap_bh
->b_data
, end
, bit
);
3568 mb_debug(1, " free preallocated %u/%u in group %u\n",
3569 (unsigned) ext4_group_first_block_no(sb
, group
) + bit
,
3570 (unsigned) next
- bit
, (unsigned) group
);
3574 ac
->ac_b_ex
.fe_group
= group
;
3575 ac
->ac_b_ex
.fe_start
= bit
;
3576 ac
->ac_b_ex
.fe_len
= next
- bit
;
3577 ac
->ac_b_ex
.fe_logical
= 0;
3578 trace_ext4_mballoc_discard(ac
);
3581 trace_ext4_mb_release_inode_pa(sb
, ac
, pa
, grp_blk_start
+ bit
,
3583 mb_free_blocks(pa
->pa_inode
, e4b
, bit
, next
- bit
);
3586 if (free
!= pa
->pa_free
) {
3587 printk(KERN_CRIT
"pa %p: logic %lu, phys. %lu, len %lu\n",
3588 pa
, (unsigned long) pa
->pa_lstart
,
3589 (unsigned long) pa
->pa_pstart
,
3590 (unsigned long) pa
->pa_len
);
3591 ext4_grp_locked_error(sb
, group
, 0, 0, "free %u, pa_free %u",
3594 * pa is already deleted so we use the value obtained
3595 * from the bitmap and continue.
3598 atomic_add(free
, &sbi
->s_mb_discarded
);
3603 static noinline_for_stack
int
3604 ext4_mb_release_group_pa(struct ext4_buddy
*e4b
,
3605 struct ext4_prealloc_space
*pa
,
3606 struct ext4_allocation_context
*ac
)
3608 struct super_block
*sb
= e4b
->bd_sb
;
3612 trace_ext4_mb_release_group_pa(sb
, ac
, pa
);
3613 BUG_ON(pa
->pa_deleted
== 0);
3614 ext4_get_group_no_and_offset(sb
, pa
->pa_pstart
, &group
, &bit
);
3615 BUG_ON(group
!= e4b
->bd_group
&& pa
->pa_len
!= 0);
3616 mb_free_blocks(pa
->pa_inode
, e4b
, bit
, pa
->pa_len
);
3617 atomic_add(pa
->pa_len
, &EXT4_SB(sb
)->s_mb_discarded
);
3621 ac
->ac_inode
= NULL
;
3622 ac
->ac_b_ex
.fe_group
= group
;
3623 ac
->ac_b_ex
.fe_start
= bit
;
3624 ac
->ac_b_ex
.fe_len
= pa
->pa_len
;
3625 ac
->ac_b_ex
.fe_logical
= 0;
3626 trace_ext4_mballoc_discard(ac
);
3633 * releases all preallocations in given group
3635 * first, we need to decide discard policy:
3636 * - when do we discard
3638 * - how many do we discard
3639 * 1) how many requested
3641 static noinline_for_stack
int
3642 ext4_mb_discard_group_preallocations(struct super_block
*sb
,
3643 ext4_group_t group
, int needed
)
3645 struct ext4_group_info
*grp
= ext4_get_group_info(sb
, group
);
3646 struct buffer_head
*bitmap_bh
= NULL
;
3647 struct ext4_prealloc_space
*pa
, *tmp
;
3648 struct ext4_allocation_context
*ac
;
3649 struct list_head list
;
3650 struct ext4_buddy e4b
;
3655 mb_debug(1, "discard preallocation for group %u\n", group
);
3657 if (list_empty(&grp
->bb_prealloc_list
))
3660 bitmap_bh
= ext4_read_block_bitmap(sb
, group
);
3661 if (bitmap_bh
== NULL
) {
3662 ext4_error(sb
, "Error reading block bitmap for %u", group
);
3666 err
= ext4_mb_load_buddy(sb
, group
, &e4b
);
3668 ext4_error(sb
, "Error loading buddy information for %u", group
);
3674 needed
= EXT4_BLOCKS_PER_GROUP(sb
) + 1;
3676 INIT_LIST_HEAD(&list
);
3677 ac
= kmem_cache_alloc(ext4_ac_cachep
, GFP_NOFS
);
3681 ext4_lock_group(sb
, group
);
3682 list_for_each_entry_safe(pa
, tmp
,
3683 &grp
->bb_prealloc_list
, pa_group_list
) {
3684 spin_lock(&pa
->pa_lock
);
3685 if (atomic_read(&pa
->pa_count
)) {
3686 spin_unlock(&pa
->pa_lock
);
3690 if (pa
->pa_deleted
) {
3691 spin_unlock(&pa
->pa_lock
);
3695 /* seems this one can be freed ... */
3698 /* we can trust pa_free ... */
3699 free
+= pa
->pa_free
;
3701 spin_unlock(&pa
->pa_lock
);
3703 list_del(&pa
->pa_group_list
);
3704 list_add(&pa
->u
.pa_tmp_list
, &list
);
3707 /* if we still need more blocks and some PAs were used, try again */
3708 if (free
< needed
&& busy
) {
3710 ext4_unlock_group(sb
, group
);
3712 * Yield the CPU here so that we don't get soft lockup
3713 * in non preempt case.
3719 /* found anything to free? */
3720 if (list_empty(&list
)) {
3725 /* now free all selected PAs */
3726 list_for_each_entry_safe(pa
, tmp
, &list
, u
.pa_tmp_list
) {
3728 /* remove from object (inode or locality group) */
3729 spin_lock(pa
->pa_obj_lock
);
3730 list_del_rcu(&pa
->pa_inode_list
);
3731 spin_unlock(pa
->pa_obj_lock
);
3733 if (pa
->pa_type
== MB_GROUP_PA
)
3734 ext4_mb_release_group_pa(&e4b
, pa
, ac
);
3736 ext4_mb_release_inode_pa(&e4b
, bitmap_bh
, pa
, ac
);
3738 list_del(&pa
->u
.pa_tmp_list
);
3739 call_rcu(&(pa
)->u
.pa_rcu
, ext4_mb_pa_callback
);
3743 ext4_unlock_group(sb
, group
);
3745 kmem_cache_free(ext4_ac_cachep
, ac
);
3746 ext4_mb_unload_buddy(&e4b
);
3752 * releases all non-used preallocated blocks for given inode
3754 * It's important to discard preallocations under i_data_sem
3755 * We don't want another block to be served from the prealloc
3756 * space when we are discarding the inode prealloc space.
3758 * FIXME!! Make sure it is valid at all the call sites
3760 void ext4_discard_preallocations(struct inode
*inode
)
3762 struct ext4_inode_info
*ei
= EXT4_I(inode
);
3763 struct super_block
*sb
= inode
->i_sb
;
3764 struct buffer_head
*bitmap_bh
= NULL
;
3765 struct ext4_prealloc_space
*pa
, *tmp
;
3766 struct ext4_allocation_context
*ac
;
3767 ext4_group_t group
= 0;
3768 struct list_head list
;
3769 struct ext4_buddy e4b
;
3772 if (!S_ISREG(inode
->i_mode
)) {
3773 /*BUG_ON(!list_empty(&ei->i_prealloc_list));*/
3777 mb_debug(1, "discard preallocation for inode %lu\n", inode
->i_ino
);
3778 trace_ext4_discard_preallocations(inode
);
3780 INIT_LIST_HEAD(&list
);
3782 ac
= kmem_cache_alloc(ext4_ac_cachep
, GFP_NOFS
);
3785 ac
->ac_inode
= inode
;
3788 /* first, collect all pa's in the inode */
3789 spin_lock(&ei
->i_prealloc_lock
);
3790 while (!list_empty(&ei
->i_prealloc_list
)) {
3791 pa
= list_entry(ei
->i_prealloc_list
.next
,
3792 struct ext4_prealloc_space
, pa_inode_list
);
3793 BUG_ON(pa
->pa_obj_lock
!= &ei
->i_prealloc_lock
);
3794 spin_lock(&pa
->pa_lock
);
3795 if (atomic_read(&pa
->pa_count
)) {
3796 /* this shouldn't happen often - nobody should
3797 * use preallocation while we're discarding it */
3798 spin_unlock(&pa
->pa_lock
);
3799 spin_unlock(&ei
->i_prealloc_lock
);
3800 printk(KERN_ERR
"uh-oh! used pa while discarding\n");
3802 schedule_timeout_uninterruptible(HZ
);
3806 if (pa
->pa_deleted
== 0) {
3808 spin_unlock(&pa
->pa_lock
);
3809 list_del_rcu(&pa
->pa_inode_list
);
3810 list_add(&pa
->u
.pa_tmp_list
, &list
);
3814 /* someone is deleting pa right now */
3815 spin_unlock(&pa
->pa_lock
);
3816 spin_unlock(&ei
->i_prealloc_lock
);
3818 /* we have to wait here because pa_deleted
3819 * doesn't mean pa is already unlinked from
3820 * the list. as we might be called from
3821 * ->clear_inode() the inode will get freed
3822 * and concurrent thread which is unlinking
3823 * pa from inode's list may access already
3824 * freed memory, bad-bad-bad */
3826 /* XXX: if this happens too often, we can
3827 * add a flag to force wait only in case
3828 * of ->clear_inode(), but not in case of
3829 * regular truncate */
3830 schedule_timeout_uninterruptible(HZ
);
3833 spin_unlock(&ei
->i_prealloc_lock
);
3835 list_for_each_entry_safe(pa
, tmp
, &list
, u
.pa_tmp_list
) {
3836 BUG_ON(pa
->pa_type
!= MB_INODE_PA
);
3837 ext4_get_group_no_and_offset(sb
, pa
->pa_pstart
, &group
, NULL
);
3839 err
= ext4_mb_load_buddy(sb
, group
, &e4b
);
3841 ext4_error(sb
, "Error loading buddy information for %u",
3846 bitmap_bh
= ext4_read_block_bitmap(sb
, group
);
3847 if (bitmap_bh
== NULL
) {
3848 ext4_error(sb
, "Error reading block bitmap for %u",
3850 ext4_mb_unload_buddy(&e4b
);
3854 ext4_lock_group(sb
, group
);
3855 list_del(&pa
->pa_group_list
);
3856 ext4_mb_release_inode_pa(&e4b
, bitmap_bh
, pa
, ac
);
3857 ext4_unlock_group(sb
, group
);
3859 ext4_mb_unload_buddy(&e4b
);
3862 list_del(&pa
->u
.pa_tmp_list
);
3863 call_rcu(&(pa
)->u
.pa_rcu
, ext4_mb_pa_callback
);
3866 kmem_cache_free(ext4_ac_cachep
, ac
);
3870 * finds all preallocated spaces and return blocks being freed to them
3871 * if preallocated space becomes full (no block is used from the space)
3872 * then the function frees space in buddy
3873 * XXX: at the moment, truncate (which is the only way to free blocks)
3874 * discards all preallocations
3876 static void ext4_mb_return_to_preallocation(struct inode
*inode
,
3877 struct ext4_buddy
*e4b
,
3878 sector_t block
, int count
)
3880 BUG_ON(!list_empty(&EXT4_I(inode
)->i_prealloc_list
));
3882 #ifdef CONFIG_EXT4_DEBUG
3883 static void ext4_mb_show_ac(struct ext4_allocation_context
*ac
)
3885 struct super_block
*sb
= ac
->ac_sb
;
3886 ext4_group_t ngroups
, i
;
3888 printk(KERN_ERR
"EXT4-fs: Can't allocate:"
3889 " Allocation context details:\n");
3890 printk(KERN_ERR
"EXT4-fs: status %d flags %d\n",
3891 ac
->ac_status
, ac
->ac_flags
);
3892 printk(KERN_ERR
"EXT4-fs: orig %lu/%lu/%lu@%lu, goal %lu/%lu/%lu@%lu, "
3893 "best %lu/%lu/%lu@%lu cr %d\n",
3894 (unsigned long)ac
->ac_o_ex
.fe_group
,
3895 (unsigned long)ac
->ac_o_ex
.fe_start
,
3896 (unsigned long)ac
->ac_o_ex
.fe_len
,
3897 (unsigned long)ac
->ac_o_ex
.fe_logical
,
3898 (unsigned long)ac
->ac_g_ex
.fe_group
,
3899 (unsigned long)ac
->ac_g_ex
.fe_start
,
3900 (unsigned long)ac
->ac_g_ex
.fe_len
,
3901 (unsigned long)ac
->ac_g_ex
.fe_logical
,
3902 (unsigned long)ac
->ac_b_ex
.fe_group
,
3903 (unsigned long)ac
->ac_b_ex
.fe_start
,
3904 (unsigned long)ac
->ac_b_ex
.fe_len
,
3905 (unsigned long)ac
->ac_b_ex
.fe_logical
,
3906 (int)ac
->ac_criteria
);
3907 printk(KERN_ERR
"EXT4-fs: %lu scanned, %d found\n", ac
->ac_ex_scanned
,
3909 printk(KERN_ERR
"EXT4-fs: groups: \n");
3910 ngroups
= ext4_get_groups_count(sb
);
3911 for (i
= 0; i
< ngroups
; i
++) {
3912 struct ext4_group_info
*grp
= ext4_get_group_info(sb
, i
);
3913 struct ext4_prealloc_space
*pa
;
3914 ext4_grpblk_t start
;
3915 struct list_head
*cur
;
3916 ext4_lock_group(sb
, i
);
3917 list_for_each(cur
, &grp
->bb_prealloc_list
) {
3918 pa
= list_entry(cur
, struct ext4_prealloc_space
,
3920 spin_lock(&pa
->pa_lock
);
3921 ext4_get_group_no_and_offset(sb
, pa
->pa_pstart
,
3923 spin_unlock(&pa
->pa_lock
);
3924 printk(KERN_ERR
"PA:%u:%d:%u \n", i
,
3927 ext4_unlock_group(sb
, i
);
3929 if (grp
->bb_free
== 0)
3931 printk(KERN_ERR
"%u: %d/%d \n",
3932 i
, grp
->bb_free
, grp
->bb_fragments
);
3934 printk(KERN_ERR
"\n");
3937 static inline void ext4_mb_show_ac(struct ext4_allocation_context
*ac
)
3944 * We use locality group preallocation for small size file. The size of the
3945 * file is determined by the current size or the resulting size after
3946 * allocation which ever is larger
3948 * One can tune this size via /sys/fs/ext4/<partition>/mb_stream_req
3950 static void ext4_mb_group_or_file(struct ext4_allocation_context
*ac
)
3952 struct ext4_sb_info
*sbi
= EXT4_SB(ac
->ac_sb
);
3953 int bsbits
= ac
->ac_sb
->s_blocksize_bits
;
3956 if (!(ac
->ac_flags
& EXT4_MB_HINT_DATA
))
3959 if (unlikely(ac
->ac_flags
& EXT4_MB_HINT_GOAL_ONLY
))
3962 size
= ac
->ac_o_ex
.fe_logical
+ ac
->ac_o_ex
.fe_len
;
3963 isize
= (i_size_read(ac
->ac_inode
) + ac
->ac_sb
->s_blocksize
- 1)
3966 if ((size
== isize
) &&
3967 !ext4_fs_is_busy(sbi
) &&
3968 (atomic_read(&ac
->ac_inode
->i_writecount
) == 0)) {
3969 ac
->ac_flags
|= EXT4_MB_HINT_NOPREALLOC
;
3973 /* don't use group allocation for large files */
3974 size
= max(size
, isize
);
3975 if (size
> sbi
->s_mb_stream_request
) {
3976 ac
->ac_flags
|= EXT4_MB_STREAM_ALLOC
;
3980 BUG_ON(ac
->ac_lg
!= NULL
);
3982 * locality group prealloc space are per cpu. The reason for having
3983 * per cpu locality group is to reduce the contention between block
3984 * request from multiple CPUs.
3986 ac
->ac_lg
= __this_cpu_ptr(sbi
->s_locality_groups
);
3988 /* we're going to use group allocation */
3989 ac
->ac_flags
|= EXT4_MB_HINT_GROUP_ALLOC
;
3991 /* serialize all allocations in the group */
3992 mutex_lock(&ac
->ac_lg
->lg_mutex
);
3995 static noinline_for_stack
int
3996 ext4_mb_initialize_context(struct ext4_allocation_context
*ac
,
3997 struct ext4_allocation_request
*ar
)
3999 struct super_block
*sb
= ar
->inode
->i_sb
;
4000 struct ext4_sb_info
*sbi
= EXT4_SB(sb
);
4001 struct ext4_super_block
*es
= sbi
->s_es
;
4005 ext4_grpblk_t block
;
4007 /* we can't allocate > group size */
4010 /* just a dirty hack to filter too big requests */
4011 if (len
>= EXT4_BLOCKS_PER_GROUP(sb
) - 10)
4012 len
= EXT4_BLOCKS_PER_GROUP(sb
) - 10;
4014 /* start searching from the goal */
4016 if (goal
< le32_to_cpu(es
->s_first_data_block
) ||
4017 goal
>= ext4_blocks_count(es
))
4018 goal
= le32_to_cpu(es
->s_first_data_block
);
4019 ext4_get_group_no_and_offset(sb
, goal
, &group
, &block
);
4021 /* set up allocation goals */
4022 memset(ac
, 0, sizeof(struct ext4_allocation_context
));
4023 ac
->ac_b_ex
.fe_logical
= ar
->logical
;
4024 ac
->ac_status
= AC_STATUS_CONTINUE
;
4026 ac
->ac_inode
= ar
->inode
;
4027 ac
->ac_o_ex
.fe_logical
= ar
->logical
;
4028 ac
->ac_o_ex
.fe_group
= group
;
4029 ac
->ac_o_ex
.fe_start
= block
;
4030 ac
->ac_o_ex
.fe_len
= len
;
4031 ac
->ac_g_ex
.fe_logical
= ar
->logical
;
4032 ac
->ac_g_ex
.fe_group
= group
;
4033 ac
->ac_g_ex
.fe_start
= block
;
4034 ac
->ac_g_ex
.fe_len
= len
;
4035 ac
->ac_flags
= ar
->flags
;
4037 /* we have to define context: we'll we work with a file or
4038 * locality group. this is a policy, actually */
4039 ext4_mb_group_or_file(ac
);
4041 mb_debug(1, "init ac: %u blocks @ %u, goal %u, flags %x, 2^%d, "
4042 "left: %u/%u, right %u/%u to %swritable\n",
4043 (unsigned) ar
->len
, (unsigned) ar
->logical
,
4044 (unsigned) ar
->goal
, ac
->ac_flags
, ac
->ac_2order
,
4045 (unsigned) ar
->lleft
, (unsigned) ar
->pleft
,
4046 (unsigned) ar
->lright
, (unsigned) ar
->pright
,
4047 atomic_read(&ar
->inode
->i_writecount
) ? "" : "non-");
4052 static noinline_for_stack
void
4053 ext4_mb_discard_lg_preallocations(struct super_block
*sb
,
4054 struct ext4_locality_group
*lg
,
4055 int order
, int total_entries
)
4057 ext4_group_t group
= 0;
4058 struct ext4_buddy e4b
;
4059 struct list_head discard_list
;
4060 struct ext4_prealloc_space
*pa
, *tmp
;
4061 struct ext4_allocation_context
*ac
;
4063 mb_debug(1, "discard locality group preallocation\n");
4065 INIT_LIST_HEAD(&discard_list
);
4066 ac
= kmem_cache_alloc(ext4_ac_cachep
, GFP_NOFS
);
4070 spin_lock(&lg
->lg_prealloc_lock
);
4071 list_for_each_entry_rcu(pa
, &lg
->lg_prealloc_list
[order
],
4073 spin_lock(&pa
->pa_lock
);
4074 if (atomic_read(&pa
->pa_count
)) {
4076 * This is the pa that we just used
4077 * for block allocation. So don't
4080 spin_unlock(&pa
->pa_lock
);
4083 if (pa
->pa_deleted
) {
4084 spin_unlock(&pa
->pa_lock
);
4087 /* only lg prealloc space */
4088 BUG_ON(pa
->pa_type
!= MB_GROUP_PA
);
4090 /* seems this one can be freed ... */
4092 spin_unlock(&pa
->pa_lock
);
4094 list_del_rcu(&pa
->pa_inode_list
);
4095 list_add(&pa
->u
.pa_tmp_list
, &discard_list
);
4098 if (total_entries
<= 5) {
4100 * we want to keep only 5 entries
4101 * allowing it to grow to 8. This
4102 * mak sure we don't call discard
4103 * soon for this list.
4108 spin_unlock(&lg
->lg_prealloc_lock
);
4110 list_for_each_entry_safe(pa
, tmp
, &discard_list
, u
.pa_tmp_list
) {
4112 ext4_get_group_no_and_offset(sb
, pa
->pa_pstart
, &group
, NULL
);
4113 if (ext4_mb_load_buddy(sb
, group
, &e4b
)) {
4114 ext4_error(sb
, "Error loading buddy information for %u",
4118 ext4_lock_group(sb
, group
);
4119 list_del(&pa
->pa_group_list
);
4120 ext4_mb_release_group_pa(&e4b
, pa
, ac
);
4121 ext4_unlock_group(sb
, group
);
4123 ext4_mb_unload_buddy(&e4b
);
4124 list_del(&pa
->u
.pa_tmp_list
);
4125 call_rcu(&(pa
)->u
.pa_rcu
, ext4_mb_pa_callback
);
4128 kmem_cache_free(ext4_ac_cachep
, ac
);
4132 * We have incremented pa_count. So it cannot be freed at this
4133 * point. Also we hold lg_mutex. So no parallel allocation is
4134 * possible from this lg. That means pa_free cannot be updated.
4136 * A parallel ext4_mb_discard_group_preallocations is possible.
4137 * which can cause the lg_prealloc_list to be updated.
4140 static void ext4_mb_add_n_trim(struct ext4_allocation_context
*ac
)
4142 int order
, added
= 0, lg_prealloc_count
= 1;
4143 struct super_block
*sb
= ac
->ac_sb
;
4144 struct ext4_locality_group
*lg
= ac
->ac_lg
;
4145 struct ext4_prealloc_space
*tmp_pa
, *pa
= ac
->ac_pa
;
4147 order
= fls(pa
->pa_free
) - 1;
4148 if (order
> PREALLOC_TB_SIZE
- 1)
4149 /* The max size of hash table is PREALLOC_TB_SIZE */
4150 order
= PREALLOC_TB_SIZE
- 1;
4151 /* Add the prealloc space to lg */
4153 list_for_each_entry_rcu(tmp_pa
, &lg
->lg_prealloc_list
[order
],
4155 spin_lock(&tmp_pa
->pa_lock
);
4156 if (tmp_pa
->pa_deleted
) {
4157 spin_unlock(&tmp_pa
->pa_lock
);
4160 if (!added
&& pa
->pa_free
< tmp_pa
->pa_free
) {
4161 /* Add to the tail of the previous entry */
4162 list_add_tail_rcu(&pa
->pa_inode_list
,
4163 &tmp_pa
->pa_inode_list
);
4166 * we want to count the total
4167 * number of entries in the list
4170 spin_unlock(&tmp_pa
->pa_lock
);
4171 lg_prealloc_count
++;
4174 list_add_tail_rcu(&pa
->pa_inode_list
,
4175 &lg
->lg_prealloc_list
[order
]);
4178 /* Now trim the list to be not more than 8 elements */
4179 if (lg_prealloc_count
> 8) {
4180 ext4_mb_discard_lg_preallocations(sb
, lg
,
4181 order
, lg_prealloc_count
);
4188 * release all resource we used in allocation
4190 static int ext4_mb_release_context(struct ext4_allocation_context
*ac
)
4192 struct ext4_prealloc_space
*pa
= ac
->ac_pa
;
4194 if (pa
->pa_type
== MB_GROUP_PA
) {
4195 /* see comment in ext4_mb_use_group_pa() */
4196 spin_lock(&pa
->pa_lock
);
4197 pa
->pa_pstart
+= ac
->ac_b_ex
.fe_len
;
4198 pa
->pa_lstart
+= ac
->ac_b_ex
.fe_len
;
4199 pa
->pa_free
-= ac
->ac_b_ex
.fe_len
;
4200 pa
->pa_len
-= ac
->ac_b_ex
.fe_len
;
4201 spin_unlock(&pa
->pa_lock
);
4205 up_read(ac
->alloc_semp
);
4208 * We want to add the pa to the right bucket.
4209 * Remove it from the list and while adding
4210 * make sure the list to which we are adding
4211 * doesn't grow big. We need to release
4212 * alloc_semp before calling ext4_mb_add_n_trim()
4214 if ((pa
->pa_type
== MB_GROUP_PA
) && likely(pa
->pa_free
)) {
4215 spin_lock(pa
->pa_obj_lock
);
4216 list_del_rcu(&pa
->pa_inode_list
);
4217 spin_unlock(pa
->pa_obj_lock
);
4218 ext4_mb_add_n_trim(ac
);
4220 ext4_mb_put_pa(ac
, ac
->ac_sb
, pa
);
4222 if (ac
->ac_bitmap_page
)
4223 page_cache_release(ac
->ac_bitmap_page
);
4224 if (ac
->ac_buddy_page
)
4225 page_cache_release(ac
->ac_buddy_page
);
4226 if (ac
->ac_flags
& EXT4_MB_HINT_GROUP_ALLOC
)
4227 mutex_unlock(&ac
->ac_lg
->lg_mutex
);
4228 ext4_mb_collect_stats(ac
);
4232 static int ext4_mb_discard_preallocations(struct super_block
*sb
, int needed
)
4234 ext4_group_t i
, ngroups
= ext4_get_groups_count(sb
);
4238 trace_ext4_mb_discard_preallocations(sb
, needed
);
4239 for (i
= 0; i
< ngroups
&& needed
> 0; i
++) {
4240 ret
= ext4_mb_discard_group_preallocations(sb
, i
, needed
);
4249 * Main entry point into mballoc to allocate blocks
4250 * it tries to use preallocation first, then falls back
4251 * to usual allocation
4253 ext4_fsblk_t
ext4_mb_new_blocks(handle_t
*handle
,
4254 struct ext4_allocation_request
*ar
, int *errp
)
4257 struct ext4_allocation_context
*ac
= NULL
;
4258 struct ext4_sb_info
*sbi
;
4259 struct super_block
*sb
;
4260 ext4_fsblk_t block
= 0;
4261 unsigned int inquota
= 0;
4262 unsigned int reserv_blks
= 0;
4264 sb
= ar
->inode
->i_sb
;
4267 trace_ext4_request_blocks(ar
);
4270 * For delayed allocation, we could skip the ENOSPC and
4271 * EDQUOT check, as blocks and quotas have been already
4272 * reserved when data being copied into pagecache.
4274 if (EXT4_I(ar
->inode
)->i_delalloc_reserved_flag
)
4275 ar
->flags
|= EXT4_MB_DELALLOC_RESERVED
;
4277 /* Without delayed allocation we need to verify
4278 * there is enough free blocks to do block allocation
4279 * and verify allocation doesn't exceed the quota limits.
4281 while (ar
->len
&& ext4_claim_free_blocks(sbi
, ar
->len
)) {
4282 /* let others to free the space */
4284 ar
->len
= ar
->len
>> 1;
4290 reserv_blks
= ar
->len
;
4291 while (ar
->len
&& dquot_alloc_block(ar
->inode
, ar
->len
)) {
4292 ar
->flags
|= EXT4_MB_HINT_NOPREALLOC
;
4302 ac
= kmem_cache_alloc(ext4_ac_cachep
, GFP_NOFS
);
4309 *errp
= ext4_mb_initialize_context(ac
, ar
);
4315 ac
->ac_op
= EXT4_MB_HISTORY_PREALLOC
;
4316 if (!ext4_mb_use_preallocated(ac
)) {
4317 ac
->ac_op
= EXT4_MB_HISTORY_ALLOC
;
4318 ext4_mb_normalize_request(ac
, ar
);
4320 /* allocate space in core */
4321 ext4_mb_regular_allocator(ac
);
4323 /* as we've just preallocated more space than
4324 * user requested orinally, we store allocated
4325 * space in a special descriptor */
4326 if (ac
->ac_status
== AC_STATUS_FOUND
&&
4327 ac
->ac_o_ex
.fe_len
< ac
->ac_b_ex
.fe_len
)
4328 ext4_mb_new_preallocation(ac
);
4330 if (likely(ac
->ac_status
== AC_STATUS_FOUND
)) {
4331 *errp
= ext4_mb_mark_diskspace_used(ac
, handle
, reserv_blks
);
4332 if (*errp
== -EAGAIN
) {
4334 * drop the reference that we took
4335 * in ext4_mb_use_best_found
4337 ext4_mb_release_context(ac
);
4338 ac
->ac_b_ex
.fe_group
= 0;
4339 ac
->ac_b_ex
.fe_start
= 0;
4340 ac
->ac_b_ex
.fe_len
= 0;
4341 ac
->ac_status
= AC_STATUS_CONTINUE
;
4344 ext4_discard_allocated_blocks(ac
);
4345 ac
->ac_b_ex
.fe_len
= 0;
4347 ext4_mb_show_ac(ac
);
4349 block
= ext4_grp_offs_to_block(sb
, &ac
->ac_b_ex
);
4350 ar
->len
= ac
->ac_b_ex
.fe_len
;
4353 freed
= ext4_mb_discard_preallocations(sb
, ac
->ac_o_ex
.fe_len
);
4357 ac
->ac_b_ex
.fe_len
= 0;
4359 ext4_mb_show_ac(ac
);
4362 ext4_mb_release_context(ac
);
4365 kmem_cache_free(ext4_ac_cachep
, ac
);
4367 if (inquota
&& ar
->len
< inquota
)
4368 dquot_free_block(ar
->inode
, inquota
- ar
->len
);
4371 if (!EXT4_I(ar
->inode
)->i_delalloc_reserved_flag
)
4372 /* release all the reserved blocks if non delalloc */
4373 percpu_counter_sub(&sbi
->s_dirtyblocks_counter
,
4377 trace_ext4_allocate_blocks(ar
, (unsigned long long)block
);
4383 * We can merge two free data extents only if the physical blocks
4384 * are contiguous, AND the extents were freed by the same transaction,
4385 * AND the blocks are associated with the same group.
4387 static int can_merge(struct ext4_free_data
*entry1
,
4388 struct ext4_free_data
*entry2
)
4390 if ((entry1
->t_tid
== entry2
->t_tid
) &&
4391 (entry1
->group
== entry2
->group
) &&
4392 ((entry1
->start_blk
+ entry1
->count
) == entry2
->start_blk
))
4397 static noinline_for_stack
int
4398 ext4_mb_free_metadata(handle_t
*handle
, struct ext4_buddy
*e4b
,
4399 struct ext4_free_data
*new_entry
)
4401 ext4_group_t group
= e4b
->bd_group
;
4402 ext4_grpblk_t block
;
4403 struct ext4_free_data
*entry
;
4404 struct ext4_group_info
*db
= e4b
->bd_info
;
4405 struct super_block
*sb
= e4b
->bd_sb
;
4406 struct ext4_sb_info
*sbi
= EXT4_SB(sb
);
4407 struct rb_node
**n
= &db
->bb_free_root
.rb_node
, *node
;
4408 struct rb_node
*parent
= NULL
, *new_node
;
4410 BUG_ON(!ext4_handle_valid(handle
));
4411 BUG_ON(e4b
->bd_bitmap_page
== NULL
);
4412 BUG_ON(e4b
->bd_buddy_page
== NULL
);
4414 new_node
= &new_entry
->node
;
4415 block
= new_entry
->start_blk
;
4418 /* first free block exent. We need to
4419 protect buddy cache from being freed,
4420 * otherwise we'll refresh it from
4421 * on-disk bitmap and lose not-yet-available
4423 page_cache_get(e4b
->bd_buddy_page
);
4424 page_cache_get(e4b
->bd_bitmap_page
);
4428 entry
= rb_entry(parent
, struct ext4_free_data
, node
);
4429 if (block
< entry
->start_blk
)
4431 else if (block
>= (entry
->start_blk
+ entry
->count
))
4432 n
= &(*n
)->rb_right
;
4434 ext4_grp_locked_error(sb
, group
, 0,
4435 ext4_group_first_block_no(sb
, group
) + block
,
4436 "Block already on to-be-freed list");
4441 rb_link_node(new_node
, parent
, n
);
4442 rb_insert_color(new_node
, &db
->bb_free_root
);
4444 /* Now try to see the extent can be merged to left and right */
4445 node
= rb_prev(new_node
);
4447 entry
= rb_entry(node
, struct ext4_free_data
, node
);
4448 if (can_merge(entry
, new_entry
)) {
4449 new_entry
->start_blk
= entry
->start_blk
;
4450 new_entry
->count
+= entry
->count
;
4451 rb_erase(node
, &(db
->bb_free_root
));
4452 spin_lock(&sbi
->s_md_lock
);
4453 list_del(&entry
->list
);
4454 spin_unlock(&sbi
->s_md_lock
);
4455 kmem_cache_free(ext4_free_ext_cachep
, entry
);
4459 node
= rb_next(new_node
);
4461 entry
= rb_entry(node
, struct ext4_free_data
, node
);
4462 if (can_merge(new_entry
, entry
)) {
4463 new_entry
->count
+= entry
->count
;
4464 rb_erase(node
, &(db
->bb_free_root
));
4465 spin_lock(&sbi
->s_md_lock
);
4466 list_del(&entry
->list
);
4467 spin_unlock(&sbi
->s_md_lock
);
4468 kmem_cache_free(ext4_free_ext_cachep
, entry
);
4471 /* Add the extent to transaction's private list */
4472 spin_lock(&sbi
->s_md_lock
);
4473 list_add(&new_entry
->list
, &handle
->h_transaction
->t_private_list
);
4474 spin_unlock(&sbi
->s_md_lock
);
4479 * ext4_free_blocks() -- Free given blocks and update quota
4480 * @handle: handle for this transaction
4482 * @block: start physical block to free
4483 * @count: number of blocks to count
4484 * @metadata: Are these metadata blocks
4486 void ext4_free_blocks(handle_t
*handle
, struct inode
*inode
,
4487 struct buffer_head
*bh
, ext4_fsblk_t block
,
4488 unsigned long count
, int flags
)
4490 struct buffer_head
*bitmap_bh
= NULL
;
4491 struct super_block
*sb
= inode
->i_sb
;
4492 struct ext4_allocation_context
*ac
= NULL
;
4493 struct ext4_group_desc
*gdp
;
4494 unsigned long freed
= 0;
4495 unsigned int overflow
;
4497 struct buffer_head
*gd_bh
;
4498 ext4_group_t block_group
;
4499 struct ext4_sb_info
*sbi
;
4500 struct ext4_buddy e4b
;
4506 BUG_ON(block
!= bh
->b_blocknr
);
4508 block
= bh
->b_blocknr
;
4512 if (!(flags
& EXT4_FREE_BLOCKS_VALIDATED
) &&
4513 !ext4_data_block_valid(sbi
, block
, count
)) {
4514 ext4_error(sb
, "Freeing blocks not in datazone - "
4515 "block = %llu, count = %lu", block
, count
);
4519 ext4_debug("freeing block %llu\n", block
);
4520 trace_ext4_free_blocks(inode
, block
, count
, flags
);
4522 if (flags
& EXT4_FREE_BLOCKS_FORGET
) {
4523 struct buffer_head
*tbh
= bh
;
4526 BUG_ON(bh
&& (count
> 1));
4528 for (i
= 0; i
< count
; i
++) {
4530 tbh
= sb_find_get_block(inode
->i_sb
,
4532 ext4_forget(handle
, flags
& EXT4_FREE_BLOCKS_METADATA
,
4533 inode
, tbh
, block
+ i
);
4538 * We need to make sure we don't reuse the freed block until
4539 * after the transaction is committed, which we can do by
4540 * treating the block as metadata, below. We make an
4541 * exception if the inode is to be written in writeback mode
4542 * since writeback mode has weak data consistency guarantees.
4544 if (!ext4_should_writeback_data(inode
))
4545 flags
|= EXT4_FREE_BLOCKS_METADATA
;
4547 ac
= kmem_cache_alloc(ext4_ac_cachep
, GFP_NOFS
);
4549 ac
->ac_inode
= inode
;
4555 ext4_get_group_no_and_offset(sb
, block
, &block_group
, &bit
);
4558 * Check to see if we are freeing blocks across a group
4561 if (bit
+ count
> EXT4_BLOCKS_PER_GROUP(sb
)) {
4562 overflow
= bit
+ count
- EXT4_BLOCKS_PER_GROUP(sb
);
4565 bitmap_bh
= ext4_read_block_bitmap(sb
, block_group
);
4570 gdp
= ext4_get_group_desc(sb
, block_group
, &gd_bh
);
4576 if (in_range(ext4_block_bitmap(sb
, gdp
), block
, count
) ||
4577 in_range(ext4_inode_bitmap(sb
, gdp
), block
, count
) ||
4578 in_range(block
, ext4_inode_table(sb
, gdp
),
4579 EXT4_SB(sb
)->s_itb_per_group
) ||
4580 in_range(block
+ count
- 1, ext4_inode_table(sb
, gdp
),
4581 EXT4_SB(sb
)->s_itb_per_group
)) {
4583 ext4_error(sb
, "Freeing blocks in system zone - "
4584 "Block = %llu, count = %lu", block
, count
);
4585 /* err = 0. ext4_std_error should be a no op */
4589 BUFFER_TRACE(bitmap_bh
, "getting write access");
4590 err
= ext4_journal_get_write_access(handle
, bitmap_bh
);
4595 * We are about to modify some metadata. Call the journal APIs
4596 * to unshare ->b_data if a currently-committing transaction is
4599 BUFFER_TRACE(gd_bh
, "get_write_access");
4600 err
= ext4_journal_get_write_access(handle
, gd_bh
);
4603 #ifdef AGGRESSIVE_CHECK
4606 for (i
= 0; i
< count
; i
++)
4607 BUG_ON(!mb_test_bit(bit
+ i
, bitmap_bh
->b_data
));
4611 ac
->ac_b_ex
.fe_group
= block_group
;
4612 ac
->ac_b_ex
.fe_start
= bit
;
4613 ac
->ac_b_ex
.fe_len
= count
;
4614 trace_ext4_mballoc_free(ac
);
4617 err
= ext4_mb_load_buddy(sb
, block_group
, &e4b
);
4621 if ((flags
& EXT4_FREE_BLOCKS_METADATA
) && ext4_handle_valid(handle
)) {
4622 struct ext4_free_data
*new_entry
;
4624 * blocks being freed are metadata. these blocks shouldn't
4625 * be used until this transaction is committed
4627 new_entry
= kmem_cache_alloc(ext4_free_ext_cachep
, GFP_NOFS
);
4628 new_entry
->start_blk
= bit
;
4629 new_entry
->group
= block_group
;
4630 new_entry
->count
= count
;
4631 new_entry
->t_tid
= handle
->h_transaction
->t_tid
;
4633 ext4_lock_group(sb
, block_group
);
4634 mb_clear_bits(bitmap_bh
->b_data
, bit
, count
);
4635 ext4_mb_free_metadata(handle
, &e4b
, new_entry
);
4637 /* need to update group_info->bb_free and bitmap
4638 * with group lock held. generate_buddy look at
4639 * them with group lock_held
4641 ext4_lock_group(sb
, block_group
);
4642 mb_clear_bits(bitmap_bh
->b_data
, bit
, count
);
4643 mb_free_blocks(inode
, &e4b
, bit
, count
);
4644 ext4_mb_return_to_preallocation(inode
, &e4b
, block
, count
);
4645 if (test_opt(sb
, DISCARD
))
4646 ext4_issue_discard(sb
, block_group
, bit
, count
);
4649 ret
= ext4_free_blks_count(sb
, gdp
) + count
;
4650 ext4_free_blks_set(sb
, gdp
, ret
);
4651 gdp
->bg_checksum
= ext4_group_desc_csum(sbi
, block_group
, gdp
);
4652 ext4_unlock_group(sb
, block_group
);
4653 percpu_counter_add(&sbi
->s_freeblocks_counter
, count
);
4655 if (sbi
->s_log_groups_per_flex
) {
4656 ext4_group_t flex_group
= ext4_flex_group(sbi
, block_group
);
4657 atomic_add(count
, &sbi
->s_flex_groups
[flex_group
].free_blocks
);
4660 ext4_mb_unload_buddy(&e4b
);
4664 /* We dirtied the bitmap block */
4665 BUFFER_TRACE(bitmap_bh
, "dirtied bitmap block");
4666 err
= ext4_handle_dirty_metadata(handle
, NULL
, bitmap_bh
);
4668 /* And the group descriptor block */
4669 BUFFER_TRACE(gd_bh
, "dirtied group descriptor block");
4670 ret
= ext4_handle_dirty_metadata(handle
, NULL
, gd_bh
);
4674 if (overflow
&& !err
) {
4680 ext4_mark_super_dirty(sb
);
4683 dquot_free_block(inode
, freed
);
4685 ext4_std_error(sb
, err
);
4687 kmem_cache_free(ext4_ac_cachep
, ac
);