1 /*
2 * Copyright (c) 2003-2006, Cluster File Systems, Inc, info@clusterfs.com
3 * Written by Alex Tomas <alex@clusterfs.com>
4 *
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.
8 *
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.
13 *
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-
17 */
18
19
20 /*
21 * mballoc.c contains the multiblocks allocation routines
22 */
23
24 #include "ext4_jbd2.h"
25 #include "mballoc.h"
26 #include <linux/log2.h>
27 #include <linux/module.h>
28 #include <linux/slab.h>
29 #include <linux/backing-dev.h>
30 #include <trace/events/ext4.h>
31
32 #ifdef CONFIG_EXT4_DEBUG
33 ushort ext4_mballoc_debug __read_mostly;
34
35 module_param_named(mballoc_debug, ext4_mballoc_debug, ushort, 0644);
36 MODULE_PARM_DESC(mballoc_debug, "Debugging level for ext4's mballoc");
37 #endif
38
39 /*
40 * MUSTDO:
41 * - test ext4_ext_search_left() and ext4_ext_search_right()
42 * - search for metadata in few groups
43 *
44 * TODO v4:
45 * - normalization should take into account whether file is still open
46 * - discard preallocations if no free space left (policy?)
47 * - don't normalize tails
48 * - quota
49 * - reservation for superuser
50 *
51 * TODO v3:
52 * - bitmap read-ahead (proposed by Oleg Drokin aka green)
53 * - track min/max extents in each group for better group selection
54 * - mb_mark_used() may allocate chunk right after splitting buddy
55 * - tree of groups sorted by number of free blocks
56 * - error handling
57 */
58
59 /*
60 * The allocation request involve request for multiple number of blocks
61 * near to the goal(block) value specified.
62 *
63 * During initialization phase of the allocator we decide to use the
64 * group preallocation or inode preallocation depending on the size of
65 * the file. The size of the file could be the resulting file size we
66 * would have after allocation, or the current file size, which ever
67 * is larger. If the size is less than sbi->s_mb_stream_request we
68 * select to use the group preallocation. The default value of
69 * s_mb_stream_request is 16 blocks. This can also be tuned via
70 * /sys/fs/ext4/<partition>/mb_stream_req. The value is represented in
71 * terms of number of blocks.
72 *
73 * The main motivation for having small file use group preallocation is to
74 * ensure that we have small files closer together on the disk.
75 *
76 * First stage the allocator looks at the inode prealloc list,
77 * ext4_inode_info->i_prealloc_list, which contains list of prealloc
78 * spaces for this particular inode. The inode prealloc space is
79 * represented as:
80 *
81 * pa_lstart -> the logical start block for this prealloc space
82 * pa_pstart -> the physical start block for this prealloc space
83 * pa_len -> length for this prealloc space (in clusters)
84 * pa_free -> free space available in this prealloc space (in clusters)
85 *
86 * The inode preallocation space is used looking at the _logical_ start
87 * block. If only the logical file block falls within the range of prealloc
88 * space we will consume the particular prealloc space. This makes sure that
89 * we have contiguous physical blocks representing the file blocks
90 *
91 * The important thing to be noted in case of inode prealloc space is that
92 * we don't modify the values associated to inode prealloc space except
93 * pa_free.
94 *
95 * If we are not able to find blocks in the inode prealloc space and if we
96 * have the group allocation flag set then we look at the locality group
97 * prealloc space. These are per CPU prealloc list represented as
98 *
99 * ext4_sb_info.s_locality_groups[smp_processor_id()]
100 *
101 * The reason for having a per cpu locality group is to reduce the contention
102 * between CPUs. It is possible to get scheduled at this point.
103 *
104 * The locality group prealloc space is used looking at whether we have
105 * enough free space (pa_free) within the prealloc space.
106 *
107 * If we can't allocate blocks via inode prealloc or/and locality group
108 * prealloc then we look at the buddy cache. The buddy cache is represented
109 * by ext4_sb_info.s_buddy_cache (struct inode) whose file offset gets
110 * mapped to the buddy and bitmap information regarding different
111 * groups. The buddy information is attached to buddy cache inode so that
112 * we can access them through the page cache. The information regarding
113 * each group is loaded via ext4_mb_load_buddy. The information involve
114 * block bitmap and buddy information. The information are stored in the
115 * inode as:
116 *
117 * { page }
118 * [ group 0 bitmap][ group 0 buddy] [group 1][ group 1]...
119 *
120 *
121 * one block each for bitmap and buddy information. So for each group we
122 * take up 2 blocks. A page can contain blocks_per_page (PAGE_CACHE_SIZE /
123 * blocksize) blocks. So it can have information regarding groups_per_page
124 * which is blocks_per_page/2
125 *
126 * The buddy cache inode is not stored on disk. The inode is thrown
127 * away when the filesystem is unmounted.
128 *
129 * We look for count number of blocks in the buddy cache. If we were able
130 * to locate that many free blocks we return with additional information
131 * regarding rest of the contiguous physical block available
132 *
133 * Before allocating blocks via buddy cache we normalize the request
134 * blocks. This ensure we ask for more blocks that we needed. The extra
135 * blocks that we get after allocation is added to the respective prealloc
136 * list. In case of inode preallocation we follow a list of heuristics
137 * based on file size. This can be found in ext4_mb_normalize_request. If
138 * we are doing a group prealloc we try to normalize the request to
139 * sbi->s_mb_group_prealloc. The default value of s_mb_group_prealloc is
140 * dependent on the cluster size; for non-bigalloc file systems, it is
141 * 512 blocks. This can be tuned via
142 * /sys/fs/ext4/<partition>/mb_group_prealloc. The value is represented in
143 * terms of number of blocks. If we have mounted the file system with -O
144 * stripe=<value> option the group prealloc request is normalized to the
145 * the smallest multiple of the stripe value (sbi->s_stripe) which is
146 * greater than the default mb_group_prealloc.
147 *
148 * The regular allocator (using the buddy cache) supports a few tunables.
149 *
150 * /sys/fs/ext4/<partition>/mb_min_to_scan
151 * /sys/fs/ext4/<partition>/mb_max_to_scan
152 * /sys/fs/ext4/<partition>/mb_order2_req
153 *
154 * The regular allocator uses buddy scan only if the request len is power of
155 * 2 blocks and the order of allocation is >= sbi->s_mb_order2_reqs. The
156 * value of s_mb_order2_reqs can be tuned via
157 * /sys/fs/ext4/<partition>/mb_order2_req. If the request len is equal to
158 * stripe size (sbi->s_stripe), we try to search for contiguous block in
159 * stripe size. This should result in better allocation on RAID setups. If
160 * not, we search in the specific group using bitmap for best extents. The
161 * tunable min_to_scan and max_to_scan control the behaviour here.
162 * min_to_scan indicate how long the mballoc __must__ look for a best
163 * extent and max_to_scan indicates how long the mballoc __can__ look for a
164 * best extent in the found extents. Searching for the blocks starts with
165 * the group specified as the goal value in allocation context via
166 * ac_g_ex. Each group is first checked based on the criteria whether it
167 * can be used for allocation. ext4_mb_good_group explains how the groups are
168 * checked.
169 *
170 * Both the prealloc space are getting populated as above. So for the first
171 * request we will hit the buddy cache which will result in this prealloc
172 * space getting filled. The prealloc space is then later used for the
173 * subsequent request.
174 */
175
176 /*
177 * mballoc operates on the following data:
178 * - on-disk bitmap
179 * - in-core buddy (actually includes buddy and bitmap)
180 * - preallocation descriptors (PAs)
181 *
182 * there are two types of preallocations:
183 * - inode
184 * assiged to specific inode and can be used for this inode only.
185 * it describes part of inode's space preallocated to specific
186 * physical blocks. any block from that preallocated can be used
187 * independent. the descriptor just tracks number of blocks left
188 * unused. so, before taking some block from descriptor, one must
189 * make sure corresponded logical block isn't allocated yet. this
190 * also means that freeing any block within descriptor's range
191 * must discard all preallocated blocks.
192 * - locality group
193 * assigned to specific locality group which does not translate to
194 * permanent set of inodes: inode can join and leave group. space
195 * from this type of preallocation can be used for any inode. thus
196 * it's consumed from the beginning to the end.
197 *
198 * relation between them can be expressed as:
199 * in-core buddy = on-disk bitmap + preallocation descriptors
200 *
201 * this mean blocks mballoc considers used are:
202 * - allocated blocks (persistent)
203 * - preallocated blocks (non-persistent)
204 *
205 * consistency in mballoc world means that at any time a block is either
206 * free or used in ALL structures. notice: "any time" should not be read
207 * literally -- time is discrete and delimited by locks.
208 *
209 * to keep it simple, we don't use block numbers, instead we count number of
210 * blocks: how many blocks marked used/free in on-disk bitmap, buddy and PA.
211 *
212 * all operations can be expressed as:
213 * - init buddy: buddy = on-disk + PAs
214 * - new PA: buddy += N; PA = N
215 * - use inode PA: on-disk += N; PA -= N
216 * - discard inode PA buddy -= on-disk - PA; PA = 0
217 * - use locality group PA on-disk += N; PA -= N
218 * - discard locality group PA buddy -= PA; PA = 0
219 * note: 'buddy -= on-disk - PA' is used to show that on-disk bitmap
220 * is used in real operation because we can't know actual used
221 * bits from PA, only from on-disk bitmap
222 *
223 * if we follow this strict logic, then all operations above should be atomic.
224 * given some of them can block, we'd have to use something like semaphores
225 * killing performance on high-end SMP hardware. let's try to relax it using
226 * the following knowledge:
227 * 1) if buddy is referenced, it's already initialized
228 * 2) while block is used in buddy and the buddy is referenced,
229 * nobody can re-allocate that block
230 * 3) we work on bitmaps and '+' actually means 'set bits'. if on-disk has
231 * bit set and PA claims same block, it's OK. IOW, one can set bit in
232 * on-disk bitmap if buddy has same bit set or/and PA covers corresponded
233 * block
234 *
235 * so, now we're building a concurrency table:
236 * - init buddy vs.
237 * - new PA
238 * blocks for PA are allocated in the buddy, buddy must be referenced
239 * until PA is linked to allocation group to avoid concurrent buddy init
240 * - use inode PA
241 * we need to make sure that either on-disk bitmap or PA has uptodate data
242 * given (3) we care that PA-=N operation doesn't interfere with init
243 * - discard inode PA
244 * the simplest way would be to have buddy initialized by the discard
245 * - use locality group PA
246 * again PA-=N must be serialized with init
247 * - discard locality group PA
248 * the simplest way would be to have buddy initialized by the discard
249 * - new PA vs.
250 * - use inode PA
251 * i_data_sem serializes them
252 * - discard inode PA
253 * discard process must wait until PA isn't used by another process
254 * - use locality group PA
255 * some mutex should serialize them
256 * - discard locality group PA
257 * discard process must wait until PA isn't used by another process
258 * - use inode PA
259 * - use inode PA
260 * i_data_sem or another mutex should serializes them
261 * - discard inode PA
262 * discard process must wait until PA isn't used by another process
263 * - use locality group PA
264 * nothing wrong here -- they're different PAs covering different blocks
265 * - discard locality group PA
266 * discard process must wait until PA isn't used by another process
267 *
268 * now we're ready to make few consequences:
269 * - PA is referenced and while it is no discard is possible
270 * - PA is referenced until block isn't marked in on-disk bitmap
271 * - PA changes only after on-disk bitmap
272 * - discard must not compete with init. either init is done before
273 * any discard or they're serialized somehow
274 * - buddy init as sum of on-disk bitmap and PAs is done atomically
275 *
276 * a special case when we've used PA to emptiness. no need to modify buddy
277 * in this case, but we should care about concurrent init
278 *
279 */
280
281 /*
282 * Logic in few words:
283 *
284 * - allocation:
285 * load group
286 * find blocks
287 * mark bits in on-disk bitmap
288 * release group
289 *
290 * - use preallocation:
291 * find proper PA (per-inode or group)
292 * load group
293 * mark bits in on-disk bitmap
294 * release group
295 * release PA
296 *
297 * - free:
298 * load group
299 * mark bits in on-disk bitmap
300 * release group
301 *
302 * - discard preallocations in group:
303 * mark PAs deleted
304 * move them onto local list
305 * load on-disk bitmap
306 * load group
307 * remove PA from object (inode or locality group)
308 * mark free blocks in-core
309 *
310 * - discard inode's preallocations:
311 */
312
313 /*
314 * Locking rules
315 *
316 * Locks:
317 * - bitlock on a group (group)
318 * - object (inode/locality) (object)
319 * - per-pa lock (pa)
320 *
321 * Paths:
322 * - new pa
323 * object
324 * group
325 *
326 * - find and use pa:
327 * pa
328 *
329 * - release consumed pa:
330 * pa
331 * group
332 * object
333 *
334 * - generate in-core bitmap:
335 * group
336 * pa
337 *
338 * - discard all for given object (inode, locality group):
339 * object
340 * pa
341 * group
342 *
343 * - discard all for given group:
344 * group
345 * pa
346 * group
347 * object
348 *
349 */
350 static struct kmem_cache *ext4_pspace_cachep;
351 static struct kmem_cache *ext4_ac_cachep;
352 static struct kmem_cache *ext4_free_data_cachep;
353
354 /* We create slab caches for groupinfo data structures based on the
355 * superblock block size. There will be one per mounted filesystem for
356 * each unique s_blocksize_bits */
357 #define NR_GRPINFO_CACHES 8
358 static struct kmem_cache *ext4_groupinfo_caches[NR_GRPINFO_CACHES];
359
360 static const char *ext4_groupinfo_slab_names[NR_GRPINFO_CACHES] = {
361 "ext4_groupinfo_1k", "ext4_groupinfo_2k", "ext4_groupinfo_4k",
362 "ext4_groupinfo_8k", "ext4_groupinfo_16k", "ext4_groupinfo_32k",
363 "ext4_groupinfo_64k", "ext4_groupinfo_128k"
364 };
365
366 static void ext4_mb_generate_from_pa(struct super_block *sb, void *bitmap,
367 ext4_group_t group);
368 static void ext4_mb_generate_from_freelist(struct super_block *sb, void *bitmap,
369 ext4_group_t group);
370 static void ext4_free_data_callback(struct super_block *sb,
371 struct ext4_journal_cb_entry *jce, int rc);
372
mb_correct_addr_and_bit(int * bit,void * addr)373 static inline void *mb_correct_addr_and_bit(int *bit, void *addr)
374 {
375 #if BITS_PER_LONG == 64
376 *bit += ((unsigned long) addr & 7UL) << 3;
377 addr = (void *) ((unsigned long) addr & ~7UL);
378 #elif BITS_PER_LONG == 32
379 *bit += ((unsigned long) addr & 3UL) << 3;
380 addr = (void *) ((unsigned long) addr & ~3UL);
381 #else
382 #error "how many bits you are?!"
383 #endif
384 return addr;
385 }
386
mb_test_bit(int bit,void * addr)387 static inline int mb_test_bit(int bit, void *addr)
388 {
389 /*
390 * ext4_test_bit on architecture like powerpc
391 * needs unsigned long aligned address
392 */
393 addr = mb_correct_addr_and_bit(&bit, addr);
394 return ext4_test_bit(bit, addr);
395 }
396
mb_set_bit(int bit,void * addr)397 static inline void mb_set_bit(int bit, void *addr)
398 {
399 addr = mb_correct_addr_and_bit(&bit, addr);
400 ext4_set_bit(bit, addr);
401 }
402
mb_clear_bit(int bit,void * addr)403 static inline void mb_clear_bit(int bit, void *addr)
404 {
405 addr = mb_correct_addr_and_bit(&bit, addr);
406 ext4_clear_bit(bit, addr);
407 }
408
mb_test_and_clear_bit(int bit,void * addr)409 static inline int mb_test_and_clear_bit(int bit, void *addr)
410 {
411 addr = mb_correct_addr_and_bit(&bit, addr);
412 return ext4_test_and_clear_bit(bit, addr);
413 }
414
mb_find_next_zero_bit(void * addr,int max,int start)415 static inline int mb_find_next_zero_bit(void *addr, int max, int start)
416 {
417 int fix = 0, ret, tmpmax;
418 addr = mb_correct_addr_and_bit(&fix, addr);
419 tmpmax = max + fix;
420 start += fix;
421
422 ret = ext4_find_next_zero_bit(addr, tmpmax, start) - fix;
423 if (ret > max)
424 return max;
425 return ret;
426 }
427
mb_find_next_bit(void * addr,int max,int start)428 static inline int mb_find_next_bit(void *addr, int max, int start)
429 {
430 int fix = 0, ret, tmpmax;
431 addr = mb_correct_addr_and_bit(&fix, addr);
432 tmpmax = max + fix;
433 start += fix;
434
435 ret = ext4_find_next_bit(addr, tmpmax, start) - fix;
436 if (ret > max)
437 return max;
438 return ret;
439 }
440
mb_find_buddy(struct ext4_buddy * e4b,int order,int * max)441 static void *mb_find_buddy(struct ext4_buddy *e4b, int order, int *max)
442 {
443 char *bb;
444
445 BUG_ON(e4b->bd_bitmap == e4b->bd_buddy);
446 BUG_ON(max == NULL);
447
448 if (order > e4b->bd_blkbits + 1) {
449 *max = 0;
450 return NULL;
451 }
452
453 /* at order 0 we see each particular block */
454 if (order == 0) {
455 *max = 1 << (e4b->bd_blkbits + 3);
456 return e4b->bd_bitmap;
457 }
458
459 bb = e4b->bd_buddy + EXT4_SB(e4b->bd_sb)->s_mb_offsets[order];
460 *max = EXT4_SB(e4b->bd_sb)->s_mb_maxs[order];
461
462 return bb;
463 }
464
465 #ifdef DOUBLE_CHECK
mb_free_blocks_double(struct inode * inode,struct ext4_buddy * e4b,int first,int count)466 static void mb_free_blocks_double(struct inode *inode, struct ext4_buddy *e4b,
467 int first, int count)
468 {
469 int i;
470 struct super_block *sb = e4b->bd_sb;
471
472 if (unlikely(e4b->bd_info->bb_bitmap == NULL))
473 return;
474 assert_spin_locked(ext4_group_lock_ptr(sb, e4b->bd_group));
475 for (i = 0; i < count; i++) {
476 if (!mb_test_bit(first + i, e4b->bd_info->bb_bitmap)) {
477 ext4_fsblk_t blocknr;
478
479 blocknr = ext4_group_first_block_no(sb, e4b->bd_group);
480 blocknr += EXT4_C2B(EXT4_SB(sb), first + i);
481 ext4_grp_locked_error(sb, e4b->bd_group,
482 inode ? inode->i_ino : 0,
483 blocknr,
484 "freeing block already freed "
485 "(bit %u)",
486 first + i);
487 }
488 mb_clear_bit(first + i, e4b->bd_info->bb_bitmap);
489 }
490 }
491
mb_mark_used_double(struct ext4_buddy * e4b,int first,int count)492 static void mb_mark_used_double(struct ext4_buddy *e4b, int first, int count)
493 {
494 int i;
495
496 if (unlikely(e4b->bd_info->bb_bitmap == NULL))
497 return;
498 assert_spin_locked(ext4_group_lock_ptr(e4b->bd_sb, e4b->bd_group));
499 for (i = 0; i < count; i++) {
500 BUG_ON(mb_test_bit(first + i, e4b->bd_info->bb_bitmap));
501 mb_set_bit(first + i, e4b->bd_info->bb_bitmap);
502 }
503 }
504
mb_cmp_bitmaps(struct ext4_buddy * e4b,void * bitmap)505 static void mb_cmp_bitmaps(struct ext4_buddy *e4b, void *bitmap)
506 {
507 if (memcmp(e4b->bd_info->bb_bitmap, bitmap, e4b->bd_sb->s_blocksize)) {
508 unsigned char *b1, *b2;
509 int i;
510 b1 = (unsigned char *) e4b->bd_info->bb_bitmap;
511 b2 = (unsigned char *) bitmap;
512 for (i = 0; i < e4b->bd_sb->s_blocksize; i++) {
513 if (b1[i] != b2[i]) {
514 ext4_msg(e4b->bd_sb, KERN_ERR,
515 "corruption in group %u "
516 "at byte %u(%u): %x in copy != %x "
517 "on disk/prealloc",
518 e4b->bd_group, i, i * 8, b1[i], b2[i]);
519 BUG();
520 }
521 }
522 }
523 }
524
525 #else
mb_free_blocks_double(struct inode * inode,struct ext4_buddy * e4b,int first,int count)526 static inline void mb_free_blocks_double(struct inode *inode,
527 struct ext4_buddy *e4b, int first, int count)
528 {
529 return;
530 }
mb_mark_used_double(struct ext4_buddy * e4b,int first,int count)531 static inline void mb_mark_used_double(struct ext4_buddy *e4b,
532 int first, int count)
533 {
534 return;
535 }
mb_cmp_bitmaps(struct ext4_buddy * e4b,void * bitmap)536 static inline void mb_cmp_bitmaps(struct ext4_buddy *e4b, void *bitmap)
537 {
538 return;
539 }
540 #endif
541
542 #ifdef AGGRESSIVE_CHECK
543
544 #define MB_CHECK_ASSERT(assert) \
545 do { \
546 if (!(assert)) { \
547 printk(KERN_EMERG \
548 "Assertion failure in %s() at %s:%d: \"%s\"\n", \
549 function, file, line, # assert); \
550 BUG(); \
551 } \
552 } while (0)
553
__mb_check_buddy(struct ext4_buddy * e4b,char * file,const char * function,int line)554 static int __mb_check_buddy(struct ext4_buddy *e4b, char *file,
555 const char *function, int line)
556 {
557 struct super_block *sb = e4b->bd_sb;
558 int order = e4b->bd_blkbits + 1;
559 int max;
560 int max2;
561 int i;
562 int j;
563 int k;
564 int count;
565 struct ext4_group_info *grp;
566 int fragments = 0;
567 int fstart;
568 struct list_head *cur;
569 void *buddy;
570 void *buddy2;
571
572 {
573 static int mb_check_counter;
574 if (mb_check_counter++ % 100 != 0)
575 return 0;
576 }
577
578 while (order > 1) {
579 buddy = mb_find_buddy(e4b, order, &max);
580 MB_CHECK_ASSERT(buddy);
581 buddy2 = mb_find_buddy(e4b, order - 1, &max2);
582 MB_CHECK_ASSERT(buddy2);
583 MB_CHECK_ASSERT(buddy != buddy2);
584 MB_CHECK_ASSERT(max * 2 == max2);
585
586 count = 0;
587 for (i = 0; i < max; i++) {
588
589 if (mb_test_bit(i, buddy)) {
590 /* only single bit in buddy2 may be 1 */
591 if (!mb_test_bit(i << 1, buddy2)) {
592 MB_CHECK_ASSERT(
593 mb_test_bit((i<<1)+1, buddy2));
594 } else if (!mb_test_bit((i << 1) + 1, buddy2)) {
595 MB_CHECK_ASSERT(
596 mb_test_bit(i << 1, buddy2));
597 }
598 continue;
599 }
600
601 /* both bits in buddy2 must be 1 */
602 MB_CHECK_ASSERT(mb_test_bit(i << 1, buddy2));
603 MB_CHECK_ASSERT(mb_test_bit((i << 1) + 1, buddy2));
604
605 for (j = 0; j < (1 << order); j++) {
606 k = (i * (1 << order)) + j;
607 MB_CHECK_ASSERT(
608 !mb_test_bit(k, e4b->bd_bitmap));
609 }
610 count++;
611 }
612 MB_CHECK_ASSERT(e4b->bd_info->bb_counters[order] == count);
613 order--;
614 }
615
616 fstart = -1;
617 buddy = mb_find_buddy(e4b, 0, &max);
618 for (i = 0; i < max; i++) {
619 if (!mb_test_bit(i, buddy)) {
620 MB_CHECK_ASSERT(i >= e4b->bd_info->bb_first_free);
621 if (fstart == -1) {
622 fragments++;
623 fstart = i;
624 }
625 continue;
626 }
627 fstart = -1;
628 /* check used bits only */
629 for (j = 0; j < e4b->bd_blkbits + 1; j++) {
630 buddy2 = mb_find_buddy(e4b, j, &max2);
631 k = i >> j;
632 MB_CHECK_ASSERT(k < max2);
633 MB_CHECK_ASSERT(mb_test_bit(k, buddy2));
634 }
635 }
636 MB_CHECK_ASSERT(!EXT4_MB_GRP_NEED_INIT(e4b->bd_info));
637 MB_CHECK_ASSERT(e4b->bd_info->bb_fragments == fragments);
638
639 grp = ext4_get_group_info(sb, e4b->bd_group);
640 list_for_each(cur, &grp->bb_prealloc_list) {
641 ext4_group_t groupnr;
642 struct ext4_prealloc_space *pa;
643 pa = list_entry(cur, struct ext4_prealloc_space, pa_group_list);
644 ext4_get_group_no_and_offset(sb, pa->pa_pstart, &groupnr, &k);
645 MB_CHECK_ASSERT(groupnr == e4b->bd_group);
646 for (i = 0; i < pa->pa_len; i++)
647 MB_CHECK_ASSERT(mb_test_bit(k + i, buddy));
648 }
649 return 0;
650 }
651 #undef MB_CHECK_ASSERT
652 #define mb_check_buddy(e4b) __mb_check_buddy(e4b, \
653 __FILE__, __func__, __LINE__)
654 #else
655 #define mb_check_buddy(e4b)
656 #endif
657
658 /*
659 * Divide blocks started from @first with length @len into
660 * smaller chunks with power of 2 blocks.
661 * Clear the bits in bitmap which the blocks of the chunk(s) covered,
662 * then increase bb_counters[] for corresponded chunk size.
663 */
ext4_mb_mark_free_simple(struct super_block * sb,void * buddy,ext4_grpblk_t first,ext4_grpblk_t len,struct ext4_group_info * grp)664 static void ext4_mb_mark_free_simple(struct super_block *sb,
665 void *buddy, ext4_grpblk_t first, ext4_grpblk_t len,
666 struct ext4_group_info *grp)
667 {
668 struct ext4_sb_info *sbi = EXT4_SB(sb);
669 ext4_grpblk_t min;
670 ext4_grpblk_t max;
671 ext4_grpblk_t chunk;
672 unsigned short border;
673
674 BUG_ON(len > EXT4_CLUSTERS_PER_GROUP(sb));
675
676 border = 2 << sb->s_blocksize_bits;
677
678 while (len > 0) {
679 /* find how many blocks can be covered since this position */
680 max = ffs(first | border) - 1;
681
682 /* find how many blocks of power 2 we need to mark */
683 min = fls(len) - 1;
684
685 if (max < min)
686 min = max;
687 chunk = 1 << min;
688
689 /* mark multiblock chunks only */
690 grp->bb_counters[min]++;
691 if (min > 0)
692 mb_clear_bit(first >> min,
693 buddy + sbi->s_mb_offsets[min]);
694
695 len -= chunk;
696 first += chunk;
697 }
698 }
699
700 /*
701 * Cache the order of the largest free extent we have available in this block
702 * group.
703 */
704 static void
mb_set_largest_free_order(struct super_block * sb,struct ext4_group_info * grp)705 mb_set_largest_free_order(struct super_block *sb, struct ext4_group_info *grp)
706 {
707 int i;
708 int bits;
709
710 grp->bb_largest_free_order = -1; /* uninit */
711
712 bits = sb->s_blocksize_bits + 1;
713 for (i = bits; i >= 0; i--) {
714 if (grp->bb_counters[i] > 0) {
715 grp->bb_largest_free_order = i;
716 break;
717 }
718 }
719 }
720
721 static noinline_for_stack
ext4_mb_generate_buddy(struct super_block * sb,void * buddy,void * bitmap,ext4_group_t group)722 void ext4_mb_generate_buddy(struct super_block *sb,
723 void *buddy, void *bitmap, ext4_group_t group)
724 {
725 struct ext4_group_info *grp = ext4_get_group_info(sb, group);
726 struct ext4_sb_info *sbi = EXT4_SB(sb);
727 ext4_grpblk_t max = EXT4_CLUSTERS_PER_GROUP(sb);
728 ext4_grpblk_t i = 0;
729 ext4_grpblk_t first;
730 ext4_grpblk_t len;
731 unsigned free = 0;
732 unsigned fragments = 0;
733 unsigned long long period = get_cycles();
734
735 /* initialize buddy from bitmap which is aggregation
736 * of on-disk bitmap and preallocations */
737 i = mb_find_next_zero_bit(bitmap, max, 0);
738 grp->bb_first_free = i;
739 while (i < max) {
740 fragments++;
741 first = i;
742 i = mb_find_next_bit(bitmap, max, i);
743 len = i - first;
744 free += len;
745 if (len > 1)
746 ext4_mb_mark_free_simple(sb, buddy, first, len, grp);
747 else
748 grp->bb_counters[0]++;
749 if (i < max)
750 i = mb_find_next_zero_bit(bitmap, max, i);
751 }
752 grp->bb_fragments = fragments;
753
754 if (free != grp->bb_free) {
755 ext4_grp_locked_error(sb, group, 0, 0,
756 "block bitmap and bg descriptor "
757 "inconsistent: %u vs %u free clusters",
758 free, grp->bb_free);
759 /*
760 * If we intend to continue, we consider group descriptor
761 * corrupt and update bb_free using bitmap value
762 */
763 grp->bb_free = free;
764 if (!EXT4_MB_GRP_BBITMAP_CORRUPT(grp))
765 percpu_counter_sub(&sbi->s_freeclusters_counter,
766 grp->bb_free);
767 set_bit(EXT4_GROUP_INFO_BBITMAP_CORRUPT_BIT, &grp->bb_state);
768 }
769 mb_set_largest_free_order(sb, grp);
770
771 clear_bit(EXT4_GROUP_INFO_NEED_INIT_BIT, &(grp->bb_state));
772
773 period = get_cycles() - period;
774 spin_lock(&EXT4_SB(sb)->s_bal_lock);
775 EXT4_SB(sb)->s_mb_buddies_generated++;
776 EXT4_SB(sb)->s_mb_generation_time += period;
777 spin_unlock(&EXT4_SB(sb)->s_bal_lock);
778 }
779
mb_regenerate_buddy(struct ext4_buddy * e4b)780 static void mb_regenerate_buddy(struct ext4_buddy *e4b)
781 {
782 int count;
783 int order = 1;
784 void *buddy;
785
786 while ((buddy = mb_find_buddy(e4b, order++, &count))) {
787 ext4_set_bits(buddy, 0, count);
788 }
789 e4b->bd_info->bb_fragments = 0;
790 memset(e4b->bd_info->bb_counters, 0,
791 sizeof(*e4b->bd_info->bb_counters) *
792 (e4b->bd_sb->s_blocksize_bits + 2));
793
794 ext4_mb_generate_buddy(e4b->bd_sb, e4b->bd_buddy,
795 e4b->bd_bitmap, e4b->bd_group);
796 }
797
798 /* The buddy information is attached the buddy cache inode
799 * for convenience. The information regarding each group
800 * is loaded via ext4_mb_load_buddy. The information involve
801 * block bitmap and buddy information. The information are
802 * stored in the inode as
803 *
804 * { page }
805 * [ group 0 bitmap][ group 0 buddy] [group 1][ group 1]...
806 *
807 *
808 * one block each for bitmap and buddy information.
809 * So for each group we take up 2 blocks. A page can
810 * contain blocks_per_page (PAGE_CACHE_SIZE / blocksize) blocks.
811 * So it can have information regarding groups_per_page which
812 * is blocks_per_page/2
813 *
814 * Locking note: This routine takes the block group lock of all groups
815 * for this page; do not hold this lock when calling this routine!
816 */
817
ext4_mb_init_cache(struct page * page,char * incore)818 static int ext4_mb_init_cache(struct page *page, char *incore)
819 {
820 ext4_group_t ngroups;
821 int blocksize;
822 int blocks_per_page;
823 int groups_per_page;
824 int err = 0;
825 int i;
826 ext4_group_t first_group, group;
827 int first_block;
828 struct super_block *sb;
829 struct buffer_head *bhs;
830 struct buffer_head **bh = NULL;
831 struct inode *inode;
832 char *data;
833 char *bitmap;
834 struct ext4_group_info *grinfo;
835
836 mb_debug(1, "init page %lu\n", page->index);
837
838 inode = page->mapping->host;
839 sb = inode->i_sb;
840 ngroups = ext4_get_groups_count(sb);
841 blocksize = 1 << inode->i_blkbits;
842 blocks_per_page = PAGE_CACHE_SIZE / blocksize;
843
844 groups_per_page = blocks_per_page >> 1;
845 if (groups_per_page == 0)
846 groups_per_page = 1;
847
848 /* allocate buffer_heads to read bitmaps */
849 if (groups_per_page > 1) {
850 i = sizeof(struct buffer_head *) * groups_per_page;
851 bh = kzalloc(i, GFP_NOFS);
852 if (bh == NULL) {
853 err = -ENOMEM;
854 goto out;
855 }
856 } else
857 bh = &bhs;
858
859 first_group = page->index * blocks_per_page / 2;
860
861 /* read all groups the page covers into the cache */
862 for (i = 0, group = first_group; i < groups_per_page; i++, group++) {
863 if (group >= ngroups)
864 break;
865
866 grinfo = ext4_get_group_info(sb, group);
867 /*
868 * If page is uptodate then we came here after online resize
869 * which added some new uninitialized group info structs, so
870 * we must skip all initialized uptodate buddies on the page,
871 * which may be currently in use by an allocating task.
872 */
873 if (PageUptodate(page) && !EXT4_MB_GRP_NEED_INIT(grinfo)) {
874 bh[i] = NULL;
875 continue;
876 }
877 bh[i] = ext4_read_block_bitmap_nowait(sb, group);
878 if (IS_ERR(bh[i])) {
879 err = PTR_ERR(bh[i]);
880 bh[i] = NULL;
881 goto out;
882 }
883 mb_debug(1, "read bitmap for group %u\n", group);
884 }
885
886 /* wait for I/O completion */
887 for (i = 0, group = first_group; i < groups_per_page; i++, group++) {
888 int err2;
889
890 if (!bh[i])
891 continue;
892 err2 = ext4_wait_block_bitmap(sb, group, bh[i]);
893 if (!err)
894 err = err2;
895 }
896
897 first_block = page->index * blocks_per_page;
898 for (i = 0; i < blocks_per_page; i++) {
899 group = (first_block + i) >> 1;
900 if (group >= ngroups)
901 break;
902
903 if (!bh[group - first_group])
904 /* skip initialized uptodate buddy */
905 continue;
906
907 if (!buffer_verified(bh[group - first_group]))
908 /* Skip faulty bitmaps */
909 continue;
910 err = 0;
911
912 /*
913 * data carry information regarding this
914 * particular group in the format specified
915 * above
916 *
917 */
918 data = page_address(page) + (i * blocksize);
919 bitmap = bh[group - first_group]->b_data;
920
921 /*
922 * We place the buddy block and bitmap block
923 * close together
924 */
925 if ((first_block + i) & 1) {
926 /* this is block of buddy */
927 BUG_ON(incore == NULL);
928 mb_debug(1, "put buddy for group %u in page %lu/%x\n",
929 group, page->index, i * blocksize);
930 trace_ext4_mb_buddy_bitmap_load(sb, group);
931 grinfo = ext4_get_group_info(sb, group);
932 grinfo->bb_fragments = 0;
933 memset(grinfo->bb_counters, 0,
934 sizeof(*grinfo->bb_counters) *
935 (sb->s_blocksize_bits+2));
936 /*
937 * incore got set to the group block bitmap below
938 */
939 ext4_lock_group(sb, group);
940 /* init the buddy */
941 memset(data, 0xff, blocksize);
942 ext4_mb_generate_buddy(sb, data, incore, group);
943 ext4_unlock_group(sb, group);
944 incore = NULL;
945 } else {
946 /* this is block of bitmap */
947 BUG_ON(incore != NULL);
948 mb_debug(1, "put bitmap for group %u in page %lu/%x\n",
949 group, page->index, i * blocksize);
950 trace_ext4_mb_bitmap_load(sb, group);
951
952 /* see comments in ext4_mb_put_pa() */
953 ext4_lock_group(sb, group);
954 memcpy(data, bitmap, blocksize);
955
956 /* mark all preallocated blks used in in-core bitmap */
957 ext4_mb_generate_from_pa(sb, data, group);
958 ext4_mb_generate_from_freelist(sb, data, group);
959 ext4_unlock_group(sb, group);
960
961 /* set incore so that the buddy information can be
962 * generated using this
963 */
964 incore = data;
965 }
966 }
967 SetPageUptodate(page);
968
969 out:
970 if (bh) {
971 for (i = 0; i < groups_per_page; i++)
972 brelse(bh[i]);
973 if (bh != &bhs)
974 kfree(bh);
975 }
976 return err;
977 }
978
979 /*
980 * Lock the buddy and bitmap pages. This make sure other parallel init_group
981 * on the same buddy page doesn't happen whild holding the buddy page lock.
982 * Return locked buddy and bitmap pages on e4b struct. If buddy and bitmap
983 * are on the same page e4b->bd_buddy_page is NULL and return value is 0.
984 */
ext4_mb_get_buddy_page_lock(struct super_block * sb,ext4_group_t group,struct ext4_buddy * e4b)985 static int ext4_mb_get_buddy_page_lock(struct super_block *sb,
986 ext4_group_t group, struct ext4_buddy *e4b)
987 {
988 struct inode *inode = EXT4_SB(sb)->s_buddy_cache;
989 int block, pnum, poff;
990 int blocks_per_page;
991 struct page *page;
992
993 e4b->bd_buddy_page = NULL;
994 e4b->bd_bitmap_page = NULL;
995
996 blocks_per_page = PAGE_CACHE_SIZE / sb->s_blocksize;
997 /*
998 * the buddy cache inode stores the block bitmap
999 * and buddy information in consecutive blocks.
1000 * So for each group we need two blocks.
1001 */
1002 block = group * 2;
1003 pnum = block / blocks_per_page;
1004 poff = block % blocks_per_page;
1005 page = find_or_create_page(inode->i_mapping, pnum, GFP_NOFS);
1006 if (!page)
1007 return -ENOMEM;
1008 BUG_ON(page->mapping != inode->i_mapping);
1009 e4b->bd_bitmap_page = page;
1010 e4b->bd_bitmap = page_address(page) + (poff * sb->s_blocksize);
1011
1012 if (blocks_per_page >= 2) {
1013 /* buddy and bitmap are on the same page */
1014 return 0;
1015 }
1016
1017 block++;
1018 pnum = block / blocks_per_page;
1019 page = find_or_create_page(inode->i_mapping, pnum, GFP_NOFS);
1020 if (!page)
1021 return -ENOMEM;
1022 BUG_ON(page->mapping != inode->i_mapping);
1023 e4b->bd_buddy_page = page;
1024 return 0;
1025 }
1026
ext4_mb_put_buddy_page_lock(struct ext4_buddy * e4b)1027 static void ext4_mb_put_buddy_page_lock(struct ext4_buddy *e4b)
1028 {
1029 if (e4b->bd_bitmap_page) {
1030 unlock_page(e4b->bd_bitmap_page);
1031 page_cache_release(e4b->bd_bitmap_page);
1032 }
1033 if (e4b->bd_buddy_page) {
1034 unlock_page(e4b->bd_buddy_page);
1035 page_cache_release(e4b->bd_buddy_page);
1036 }
1037 }
1038
1039 /*
1040 * Locking note: This routine calls ext4_mb_init_cache(), which takes the
1041 * block group lock of all groups for this page; do not hold the BG lock when
1042 * calling this routine!
1043 */
1044 static noinline_for_stack
ext4_mb_init_group(struct super_block * sb,ext4_group_t group)1045 int ext4_mb_init_group(struct super_block *sb, ext4_group_t group)
1046 {
1047
1048 struct ext4_group_info *this_grp;
1049 struct ext4_buddy e4b;
1050 struct page *page;
1051 int ret = 0;
1052
1053 might_sleep();
1054 mb_debug(1, "init group %u\n", group);
1055 this_grp = ext4_get_group_info(sb, group);
1056 /*
1057 * This ensures that we don't reinit the buddy cache
1058 * page which map to the group from which we are already
1059 * allocating. If we are looking at the buddy cache we would
1060 * have taken a reference using ext4_mb_load_buddy and that
1061 * would have pinned buddy page to page cache.
1062 * The call to ext4_mb_get_buddy_page_lock will mark the
1063 * page accessed.
1064 */
1065 ret = ext4_mb_get_buddy_page_lock(sb, group, &e4b);
1066 if (ret || !EXT4_MB_GRP_NEED_INIT(this_grp)) {
1067 /*
1068 * somebody initialized the group
1069 * return without doing anything
1070 */
1071 goto err;
1072 }
1073
1074 page = e4b.bd_bitmap_page;
1075 ret = ext4_mb_init_cache(page, NULL);
1076 if (ret)
1077 goto err;
1078 if (!PageUptodate(page)) {
1079 ret = -EIO;
1080 goto err;
1081 }
1082
1083 if (e4b.bd_buddy_page == NULL) {
1084 /*
1085 * If both the bitmap and buddy are in
1086 * the same page we don't need to force
1087 * init the buddy
1088 */
1089 ret = 0;
1090 goto err;
1091 }
1092 /* init buddy cache */
1093 page = e4b.bd_buddy_page;
1094 ret = ext4_mb_init_cache(page, e4b.bd_bitmap);
1095 if (ret)
1096 goto err;
1097 if (!PageUptodate(page)) {
1098 ret = -EIO;
1099 goto err;
1100 }
1101 err:
1102 ext4_mb_put_buddy_page_lock(&e4b);
1103 return ret;
1104 }
1105
1106 /*
1107 * Locking note: This routine calls ext4_mb_init_cache(), which takes the
1108 * block group lock of all groups for this page; do not hold the BG lock when
1109 * calling this routine!
1110 */
1111 static noinline_for_stack int
ext4_mb_load_buddy(struct super_block * sb,ext4_group_t group,struct ext4_buddy * e4b)1112 ext4_mb_load_buddy(struct super_block *sb, ext4_group_t group,
1113 struct ext4_buddy *e4b)
1114 {
1115 int blocks_per_page;
1116 int block;
1117 int pnum;
1118 int poff;
1119 struct page *page;
1120 int ret;
1121 struct ext4_group_info *grp;
1122 struct ext4_sb_info *sbi = EXT4_SB(sb);
1123 struct inode *inode = sbi->s_buddy_cache;
1124
1125 might_sleep();
1126 mb_debug(1, "load group %u\n", group);
1127
1128 blocks_per_page = PAGE_CACHE_SIZE / sb->s_blocksize;
1129 grp = ext4_get_group_info(sb, group);
1130
1131 e4b->bd_blkbits = sb->s_blocksize_bits;
1132 e4b->bd_info = grp;
1133 e4b->bd_sb = sb;
1134 e4b->bd_group = group;
1135 e4b->bd_buddy_page = NULL;
1136 e4b->bd_bitmap_page = NULL;
1137
1138 if (unlikely(EXT4_MB_GRP_NEED_INIT(grp))) {
1139 /*
1140 * we need full data about the group
1141 * to make a good selection
1142 */
1143 ret = ext4_mb_init_group(sb, group);
1144 if (ret)
1145 return ret;
1146 }
1147
1148 /*
1149 * the buddy cache inode stores the block bitmap
1150 * and buddy information in consecutive blocks.
1151 * So for each group we need two blocks.
1152 */
1153 block = group * 2;
1154 pnum = block / blocks_per_page;
1155 poff = block % blocks_per_page;
1156
1157 /* we could use find_or_create_page(), but it locks page
1158 * what we'd like to avoid in fast path ... */
1159 page = find_get_page_flags(inode->i_mapping, pnum, FGP_ACCESSED);
1160 if (page == NULL || !PageUptodate(page)) {
1161 if (page)
1162 /*
1163 * drop the page reference and try
1164 * to get the page with lock. If we
1165 * are not uptodate that implies
1166 * somebody just created the page but
1167 * is yet to initialize the same. So
1168 * wait for it to initialize.
1169 */
1170 page_cache_release(page);
1171 page = find_or_create_page(inode->i_mapping, pnum, GFP_NOFS);
1172 if (page) {
1173 BUG_ON(page->mapping != inode->i_mapping);
1174 if (!PageUptodate(page)) {
1175 ret = ext4_mb_init_cache(page, NULL);
1176 if (ret) {
1177 unlock_page(page);
1178 goto err;
1179 }
1180 mb_cmp_bitmaps(e4b, page_address(page) +
1181 (poff * sb->s_blocksize));
1182 }
1183 unlock_page(page);
1184 }
1185 }
1186 if (page == NULL) {
1187 ret = -ENOMEM;
1188 goto err;
1189 }
1190 if (!PageUptodate(page)) {
1191 ret = -EIO;
1192 goto err;
1193 }
1194
1195 /* Pages marked accessed already */
1196 e4b->bd_bitmap_page = page;
1197 e4b->bd_bitmap = page_address(page) + (poff * sb->s_blocksize);
1198
1199 block++;
1200 pnum = block / blocks_per_page;
1201 poff = block % blocks_per_page;
1202
1203 page = find_get_page_flags(inode->i_mapping, pnum, FGP_ACCESSED);
1204 if (page == NULL || !PageUptodate(page)) {
1205 if (page)
1206 page_cache_release(page);
1207 page = find_or_create_page(inode->i_mapping, pnum, GFP_NOFS);
1208 if (page) {
1209 BUG_ON(page->mapping != inode->i_mapping);
1210 if (!PageUptodate(page)) {
1211 ret = ext4_mb_init_cache(page, e4b->bd_bitmap);
1212 if (ret) {
1213 unlock_page(page);
1214 goto err;
1215 }
1216 }
1217 unlock_page(page);
1218 }
1219 }
1220 if (page == NULL) {
1221 ret = -ENOMEM;
1222 goto err;
1223 }
1224 if (!PageUptodate(page)) {
1225 ret = -EIO;
1226 goto err;
1227 }
1228
1229 /* Pages marked accessed already */
1230 e4b->bd_buddy_page = page;
1231 e4b->bd_buddy = page_address(page) + (poff * sb->s_blocksize);
1232
1233 BUG_ON(e4b->bd_bitmap_page == NULL);
1234 BUG_ON(e4b->bd_buddy_page == NULL);
1235
1236 return 0;
1237
1238 err:
1239 if (page)
1240 page_cache_release(page);
1241 if (e4b->bd_bitmap_page)
1242 page_cache_release(e4b->bd_bitmap_page);
1243 if (e4b->bd_buddy_page)
1244 page_cache_release(e4b->bd_buddy_page);
1245 e4b->bd_buddy = NULL;
1246 e4b->bd_bitmap = NULL;
1247 return ret;
1248 }
1249
ext4_mb_unload_buddy(struct ext4_buddy * e4b)1250 static void ext4_mb_unload_buddy(struct ext4_buddy *e4b)
1251 {
1252 if (e4b->bd_bitmap_page)
1253 page_cache_release(e4b->bd_bitmap_page);
1254 if (e4b->bd_buddy_page)
1255 page_cache_release(e4b->bd_buddy_page);
1256 }
1257
1258
mb_find_order_for_block(struct ext4_buddy * e4b,int block)1259 static int mb_find_order_for_block(struct ext4_buddy *e4b, int block)
1260 {
1261 int order = 1;
1262 int bb_incr = 1 << (e4b->bd_blkbits - 1);
1263 void *bb;
1264
1265 BUG_ON(e4b->bd_bitmap == e4b->bd_buddy);
1266 BUG_ON(block >= (1 << (e4b->bd_blkbits + 3)));
1267
1268 bb = e4b->bd_buddy;
1269 while (order <= e4b->bd_blkbits + 1) {
1270 block = block >> 1;
1271 if (!mb_test_bit(block, bb)) {
1272 /* this block is part of buddy of order 'order' */
1273 return order;
1274 }
1275 bb += bb_incr;
1276 bb_incr >>= 1;
1277 order++;
1278 }
1279 return 0;
1280 }
1281
mb_clear_bits(void * bm,int cur,int len)1282 static void mb_clear_bits(void *bm, int cur, int len)
1283 {
1284 __u32 *addr;
1285
1286 len = cur + len;
1287 while (cur < len) {
1288 if ((cur & 31) == 0 && (len - cur) >= 32) {
1289 /* fast path: clear whole word at once */
1290 addr = bm + (cur >> 3);
1291 *addr = 0;
1292 cur += 32;
1293 continue;
1294 }
1295 mb_clear_bit(cur, bm);
1296 cur++;
1297 }
1298 }
1299
1300 /* clear bits in given range
1301 * will return first found zero bit if any, -1 otherwise
1302 */
mb_test_and_clear_bits(void * bm,int cur,int len)1303 static int mb_test_and_clear_bits(void *bm, int cur, int len)
1304 {
1305 __u32 *addr;
1306 int zero_bit = -1;
1307
1308 len = cur + len;
1309 while (cur < len) {
1310 if ((cur & 31) == 0 && (len - cur) >= 32) {
1311 /* fast path: clear whole word at once */
1312 addr = bm + (cur >> 3);
1313 if (*addr != (__u32)(-1) && zero_bit == -1)
1314 zero_bit = cur + mb_find_next_zero_bit(addr, 32, 0);
1315 *addr = 0;
1316 cur += 32;
1317 continue;
1318 }
1319 if (!mb_test_and_clear_bit(cur, bm) && zero_bit == -1)
1320 zero_bit = cur;
1321 cur++;
1322 }
1323
1324 return zero_bit;
1325 }
1326
ext4_set_bits(void * bm,int cur,int len)1327 void ext4_set_bits(void *bm, int cur, int len)
1328 {
1329 __u32 *addr;
1330
1331 len = cur + len;
1332 while (cur < len) {
1333 if ((cur & 31) == 0 && (len - cur) >= 32) {
1334 /* fast path: set whole word at once */
1335 addr = bm + (cur >> 3);
1336 *addr = 0xffffffff;
1337 cur += 32;
1338 continue;
1339 }
1340 mb_set_bit(cur, bm);
1341 cur++;
1342 }
1343 }
1344
1345 /*
1346 * _________________________________________________________________ */
1347
mb_buddy_adjust_border(int * bit,void * bitmap,int side)1348 static inline int mb_buddy_adjust_border(int* bit, void* bitmap, int side)
1349 {
1350 if (mb_test_bit(*bit + side, bitmap)) {
1351 mb_clear_bit(*bit, bitmap);
1352 (*bit) -= side;
1353 return 1;
1354 }
1355 else {
1356 (*bit) += side;
1357 mb_set_bit(*bit, bitmap);
1358 return -1;
1359 }
1360 }
1361
mb_buddy_mark_free(struct ext4_buddy * e4b,int first,int last)1362 static void mb_buddy_mark_free(struct ext4_buddy *e4b, int first, int last)
1363 {
1364 int max;
1365 int order = 1;
1366 void *buddy = mb_find_buddy(e4b, order, &max);
1367
1368 while (buddy) {
1369 void *buddy2;
1370
1371 /* Bits in range [first; last] are known to be set since
1372 * corresponding blocks were allocated. Bits in range
1373 * (first; last) will stay set because they form buddies on
1374 * upper layer. We just deal with borders if they don't
1375 * align with upper layer and then go up.
1376 * Releasing entire group is all about clearing
1377 * single bit of highest order buddy.
1378 */
1379
1380 /* Example:
1381 * ---------------------------------
1382 * | 1 | 1 | 1 | 1 |
1383 * ---------------------------------
1384 * | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
1385 * ---------------------------------
1386 * 0 1 2 3 4 5 6 7
1387 * \_____________________/
1388 *
1389 * Neither [1] nor [6] is aligned to above layer.
1390 * Left neighbour [0] is free, so mark it busy,
1391 * decrease bb_counters and extend range to
1392 * [0; 6]
1393 * Right neighbour [7] is busy. It can't be coaleasced with [6], so
1394 * mark [6] free, increase bb_counters and shrink range to
1395 * [0; 5].
1396 * Then shift range to [0; 2], go up and do the same.
1397 */
1398
1399
1400 if (first & 1)
1401 e4b->bd_info->bb_counters[order] += mb_buddy_adjust_border(&first, buddy, -1);
1402 if (!(last & 1))
1403 e4b->bd_info->bb_counters[order] += mb_buddy_adjust_border(&last, buddy, 1);
1404 if (first > last)
1405 break;
1406 order++;
1407
1408 if (first == last || !(buddy2 = mb_find_buddy(e4b, order, &max))) {
1409 mb_clear_bits(buddy, first, last - first + 1);
1410 e4b->bd_info->bb_counters[order - 1] += last - first + 1;
1411 break;
1412 }
1413 first >>= 1;
1414 last >>= 1;
1415 buddy = buddy2;
1416 }
1417 }
1418
mb_free_blocks(struct inode * inode,struct ext4_buddy * e4b,int first,int count)1419 static void mb_free_blocks(struct inode *inode, struct ext4_buddy *e4b,
1420 int first, int count)
1421 {
1422 int left_is_free = 0;
1423 int right_is_free = 0;
1424 int block;
1425 int last = first + count - 1;
1426 struct super_block *sb = e4b->bd_sb;
1427
1428 if (WARN_ON(count == 0))
1429 return;
1430 BUG_ON(last >= (sb->s_blocksize << 3));
1431 assert_spin_locked(ext4_group_lock_ptr(sb, e4b->bd_group));
1432 /* Don't bother if the block group is corrupt. */
1433 if (unlikely(EXT4_MB_GRP_BBITMAP_CORRUPT(e4b->bd_info)))
1434 return;
1435
1436 mb_check_buddy(e4b);
1437 mb_free_blocks_double(inode, e4b, first, count);
1438
1439 e4b->bd_info->bb_free += count;
1440 if (first < e4b->bd_info->bb_first_free)
1441 e4b->bd_info->bb_first_free = first;
1442
1443 /* access memory sequentially: check left neighbour,
1444 * clear range and then check right neighbour
1445 */
1446 if (first != 0)
1447 left_is_free = !mb_test_bit(first - 1, e4b->bd_bitmap);
1448 block = mb_test_and_clear_bits(e4b->bd_bitmap, first, count);
1449 if (last + 1 < EXT4_SB(sb)->s_mb_maxs[0])
1450 right_is_free = !mb_test_bit(last + 1, e4b->bd_bitmap);
1451
1452 if (unlikely(block != -1)) {
1453 struct ext4_sb_info *sbi = EXT4_SB(sb);
1454 ext4_fsblk_t blocknr;
1455
1456 blocknr = ext4_group_first_block_no(sb, e4b->bd_group);
1457 blocknr += EXT4_C2B(EXT4_SB(sb), block);
1458 ext4_grp_locked_error(sb, e4b->bd_group,
1459 inode ? inode->i_ino : 0,
1460 blocknr,
1461 "freeing already freed block "
1462 "(bit %u); block bitmap corrupt.",
1463 block);
1464 if (!EXT4_MB_GRP_BBITMAP_CORRUPT(e4b->bd_info))
1465 percpu_counter_sub(&sbi->s_freeclusters_counter,
1466 e4b->bd_info->bb_free);
1467 /* Mark the block group as corrupt. */
1468 set_bit(EXT4_GROUP_INFO_BBITMAP_CORRUPT_BIT,
1469 &e4b->bd_info->bb_state);
1470 mb_regenerate_buddy(e4b);
1471 goto done;
1472 }
1473
1474 /* let's maintain fragments counter */
1475 if (left_is_free && right_is_free)
1476 e4b->bd_info->bb_fragments--;
1477 else if (!left_is_free && !right_is_free)
1478 e4b->bd_info->bb_fragments++;
1479
1480 /* buddy[0] == bd_bitmap is a special case, so handle
1481 * it right away and let mb_buddy_mark_free stay free of
1482 * zero order checks.
1483 * Check if neighbours are to be coaleasced,
1484 * adjust bitmap bb_counters and borders appropriately.
1485 */
1486 if (first & 1) {
1487 first += !left_is_free;
1488 e4b->bd_info->bb_counters[0] += left_is_free ? -1 : 1;
1489 }
1490 if (!(last & 1)) {
1491 last -= !right_is_free;
1492 e4b->bd_info->bb_counters[0] += right_is_free ? -1 : 1;
1493 }
1494
1495 if (first <= last)
1496 mb_buddy_mark_free(e4b, first >> 1, last >> 1);
1497
1498 done:
1499 mb_set_largest_free_order(sb, e4b->bd_info);
1500 mb_check_buddy(e4b);
1501 }
1502
mb_find_extent(struct ext4_buddy * e4b,int block,int needed,struct ext4_free_extent * ex)1503 static int mb_find_extent(struct ext4_buddy *e4b, int block,
1504 int needed, struct ext4_free_extent *ex)
1505 {
1506 int next = block;
1507 int max, order;
1508 void *buddy;
1509
1510 assert_spin_locked(ext4_group_lock_ptr(e4b->bd_sb, e4b->bd_group));
1511 BUG_ON(ex == NULL);
1512
1513 buddy = mb_find_buddy(e4b, 0, &max);
1514 BUG_ON(buddy == NULL);
1515 BUG_ON(block >= max);
1516 if (mb_test_bit(block, buddy)) {
1517 ex->fe_len = 0;
1518 ex->fe_start = 0;
1519 ex->fe_group = 0;
1520 return 0;
1521 }
1522
1523 /* find actual order */
1524 order = mb_find_order_for_block(e4b, block);
1525 block = block >> order;
1526
1527 ex->fe_len = 1 << order;
1528 ex->fe_start = block << order;
1529 ex->fe_group = e4b->bd_group;
1530
1531 /* calc difference from given start */
1532 next = next - ex->fe_start;
1533 ex->fe_len -= next;
1534 ex->fe_start += next;
1535
1536 while (needed > ex->fe_len &&
1537 mb_find_buddy(e4b, order, &max)) {
1538
1539 if (block + 1 >= max)
1540 break;
1541
1542 next = (block + 1) * (1 << order);
1543 if (mb_test_bit(next, e4b->bd_bitmap))
1544 break;
1545
1546 order = mb_find_order_for_block(e4b, next);
1547
1548 block = next >> order;
1549 ex->fe_len += 1 << order;
1550 }
1551
1552 BUG_ON(ex->fe_start + ex->fe_len > (1 << (e4b->bd_blkbits + 3)));
1553 return ex->fe_len;
1554 }
1555
mb_mark_used(struct ext4_buddy * e4b,struct ext4_free_extent * ex)1556 static int mb_mark_used(struct ext4_buddy *e4b, struct ext4_free_extent *ex)
1557 {
1558 int ord;
1559 int mlen = 0;
1560 int max = 0;
1561 int cur;
1562 int start = ex->fe_start;
1563 int len = ex->fe_len;
1564 unsigned ret = 0;
1565 int len0 = len;
1566 void *buddy;
1567
1568 BUG_ON(start + len > (e4b->bd_sb->s_blocksize << 3));
1569 BUG_ON(e4b->bd_group != ex->fe_group);
1570 assert_spin_locked(ext4_group_lock_ptr(e4b->bd_sb, e4b->bd_group));
1571 mb_check_buddy(e4b);
1572 mb_mark_used_double(e4b, start, len);
1573
1574 e4b->bd_info->bb_free -= len;
1575 if (e4b->bd_info->bb_first_free == start)
1576 e4b->bd_info->bb_first_free += len;
1577
1578 /* let's maintain fragments counter */
1579 if (start != 0)
1580 mlen = !mb_test_bit(start - 1, e4b->bd_bitmap);
1581 if (start + len < EXT4_SB(e4b->bd_sb)->s_mb_maxs[0])
1582 max = !mb_test_bit(start + len, e4b->bd_bitmap);
1583 if (mlen && max)
1584 e4b->bd_info->bb_fragments++;
1585 else if (!mlen && !max)
1586 e4b->bd_info->bb_fragments--;
1587
1588 /* let's maintain buddy itself */
1589 while (len) {
1590 ord = mb_find_order_for_block(e4b, start);
1591
1592 if (((start >> ord) << ord) == start && len >= (1 << ord)) {
1593 /* the whole chunk may be allocated at once! */
1594 mlen = 1 << ord;
1595 buddy = mb_find_buddy(e4b, ord, &max);
1596 BUG_ON((start >> ord) >= max);
1597 mb_set_bit(start >> ord, buddy);
1598 e4b->bd_info->bb_counters[ord]--;
1599 start += mlen;
1600 len -= mlen;
1601 BUG_ON(len < 0);
1602 continue;
1603 }
1604
1605 /* store for history */
1606 if (ret == 0)
1607 ret = len | (ord << 16);
1608
1609 /* we have to split large buddy */
1610 BUG_ON(ord <= 0);
1611 buddy = mb_find_buddy(e4b, ord, &max);
1612 mb_set_bit(start >> ord, buddy);
1613 e4b->bd_info->bb_counters[ord]--;
1614
1615 ord--;
1616 cur = (start >> ord) & ~1U;
1617 buddy = mb_find_buddy(e4b, ord, &max);
1618 mb_clear_bit(cur, buddy);
1619 mb_clear_bit(cur + 1, buddy);
1620 e4b->bd_info->bb_counters[ord]++;
1621 e4b->bd_info->bb_counters[ord]++;
1622 }
1623 mb_set_largest_free_order(e4b->bd_sb, e4b->bd_info);
1624
1625 ext4_set_bits(e4b->bd_bitmap, ex->fe_start, len0);
1626 mb_check_buddy(e4b);
1627
1628 return ret;
1629 }
1630
1631 /*
1632 * Must be called under group lock!
1633 */
ext4_mb_use_best_found(struct ext4_allocation_context * ac,struct ext4_buddy * e4b)1634 static void ext4_mb_use_best_found(struct ext4_allocation_context *ac,
1635 struct ext4_buddy *e4b)
1636 {
1637 struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
1638 int ret;
1639
1640 BUG_ON(ac->ac_b_ex.fe_group != e4b->bd_group);
1641 BUG_ON(ac->ac_status == AC_STATUS_FOUND);
1642
1643 ac->ac_b_ex.fe_len = min(ac->ac_b_ex.fe_len, ac->ac_g_ex.fe_len);
1644 ac->ac_b_ex.fe_logical = ac->ac_g_ex.fe_logical;
1645 ret = mb_mark_used(e4b, &ac->ac_b_ex);
1646
1647 /* preallocation can change ac_b_ex, thus we store actually
1648 * allocated blocks for history */
1649 ac->ac_f_ex = ac->ac_b_ex;
1650
1651 ac->ac_status = AC_STATUS_FOUND;
1652 ac->ac_tail = ret & 0xffff;
1653 ac->ac_buddy = ret >> 16;
1654
1655 /*
1656 * take the page reference. We want the page to be pinned
1657 * so that we don't get a ext4_mb_init_cache_call for this
1658 * group until we update the bitmap. That would mean we
1659 * double allocate blocks. The reference is dropped
1660 * in ext4_mb_release_context
1661 */
1662 ac->ac_bitmap_page = e4b->bd_bitmap_page;
1663 get_page(ac->ac_bitmap_page);
1664 ac->ac_buddy_page = e4b->bd_buddy_page;
1665 get_page(ac->ac_buddy_page);
1666 /* store last allocated for subsequent stream allocation */
1667 if (ac->ac_flags & EXT4_MB_STREAM_ALLOC) {
1668 spin_lock(&sbi->s_md_lock);
1669 sbi->s_mb_last_group = ac->ac_f_ex.fe_group;
1670 sbi->s_mb_last_start = ac->ac_f_ex.fe_start;
1671 spin_unlock(&sbi->s_md_lock);
1672 }
1673 }
1674
1675 /*
1676 * regular allocator, for general purposes allocation
1677 */
1678
ext4_mb_check_limits(struct ext4_allocation_context * ac,struct ext4_buddy * e4b,int finish_group)1679 static void ext4_mb_check_limits(struct ext4_allocation_context *ac,
1680 struct ext4_buddy *e4b,
1681 int finish_group)
1682 {
1683 struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
1684 struct ext4_free_extent *bex = &ac->ac_b_ex;
1685 struct ext4_free_extent *gex = &ac->ac_g_ex;
1686 struct ext4_free_extent ex;
1687 int max;
1688
1689 if (ac->ac_status == AC_STATUS_FOUND)
1690 return;
1691 /*
1692 * We don't want to scan for a whole year
1693 */
1694 if (ac->ac_found > sbi->s_mb_max_to_scan &&
1695 !(ac->ac_flags & EXT4_MB_HINT_FIRST)) {
1696 ac->ac_status = AC_STATUS_BREAK;
1697 return;
1698 }
1699
1700 /*
1701 * Haven't found good chunk so far, let's continue
1702 */
1703 if (bex->fe_len < gex->fe_len)
1704 return;
1705
1706 if ((finish_group || ac->ac_found > sbi->s_mb_min_to_scan)
1707 && bex->fe_group == e4b->bd_group) {
1708 /* recheck chunk's availability - we don't know
1709 * when it was found (within this lock-unlock
1710 * period or not) */
1711 max = mb_find_extent(e4b, bex->fe_start, gex->fe_len, &ex);
1712 if (max >= gex->fe_len) {
1713 ext4_mb_use_best_found(ac, e4b);
1714 return;
1715 }
1716 }
1717 }
1718
1719 /*
1720 * The routine checks whether found extent is good enough. If it is,
1721 * then the extent gets marked used and flag is set to the context
1722 * to stop scanning. Otherwise, the extent is compared with the
1723 * previous found extent and if new one is better, then it's stored
1724 * in the context. Later, the best found extent will be used, if
1725 * mballoc can't find good enough extent.
1726 *
1727 * FIXME: real allocation policy is to be designed yet!
1728 */
ext4_mb_measure_extent(struct ext4_allocation_context * ac,struct ext4_free_extent * ex,struct ext4_buddy * e4b)1729 static void ext4_mb_measure_extent(struct ext4_allocation_context *ac,
1730 struct ext4_free_extent *ex,
1731 struct ext4_buddy *e4b)
1732 {
1733 struct ext4_free_extent *bex = &ac->ac_b_ex;
1734 struct ext4_free_extent *gex = &ac->ac_g_ex;
1735
1736 BUG_ON(ex->fe_len <= 0);
1737 BUG_ON(ex->fe_len > EXT4_CLUSTERS_PER_GROUP(ac->ac_sb));
1738 BUG_ON(ex->fe_start >= EXT4_CLUSTERS_PER_GROUP(ac->ac_sb));
1739 BUG_ON(ac->ac_status != AC_STATUS_CONTINUE);
1740
1741 ac->ac_found++;
1742
1743 /*
1744 * The special case - take what you catch first
1745 */
1746 if (unlikely(ac->ac_flags & EXT4_MB_HINT_FIRST)) {
1747 *bex = *ex;
1748 ext4_mb_use_best_found(ac, e4b);
1749 return;
1750 }
1751
1752 /*
1753 * Let's check whether the chuck is good enough
1754 */
1755 if (ex->fe_len == gex->fe_len) {
1756 *bex = *ex;
1757 ext4_mb_use_best_found(ac, e4b);
1758 return;
1759 }
1760
1761 /*
1762 * If this is first found extent, just store it in the context
1763 */
1764 if (bex->fe_len == 0) {
1765 *bex = *ex;
1766 return;
1767 }
1768
1769 /*
1770 * If new found extent is better, store it in the context
1771 */
1772 if (bex->fe_len < gex->fe_len) {
1773 /* if the request isn't satisfied, any found extent
1774 * larger than previous best one is better */
1775 if (ex->fe_len > bex->fe_len)
1776 *bex = *ex;
1777 } else if (ex->fe_len > gex->fe_len) {
1778 /* if the request is satisfied, then we try to find
1779 * an extent that still satisfy the request, but is
1780 * smaller than previous one */
1781 if (ex->fe_len < bex->fe_len)
1782 *bex = *ex;
1783 }
1784
1785 ext4_mb_check_limits(ac, e4b, 0);
1786 }
1787
1788 static noinline_for_stack
ext4_mb_try_best_found(struct ext4_allocation_context * ac,struct ext4_buddy * e4b)1789 int ext4_mb_try_best_found(struct ext4_allocation_context *ac,
1790 struct ext4_buddy *e4b)
1791 {
1792 struct ext4_free_extent ex = ac->ac_b_ex;
1793 ext4_group_t group = ex.fe_group;
1794 int max;
1795 int err;
1796
1797 BUG_ON(ex.fe_len <= 0);
1798 err = ext4_mb_load_buddy(ac->ac_sb, group, e4b);
1799 if (err)
1800 return err;
1801
1802 ext4_lock_group(ac->ac_sb, group);
1803 max = mb_find_extent(e4b, ex.fe_start, ex.fe_len, &ex);
1804
1805 if (max > 0) {
1806 ac->ac_b_ex = ex;
1807 ext4_mb_use_best_found(ac, e4b);
1808 }
1809
1810 ext4_unlock_group(ac->ac_sb, group);
1811 ext4_mb_unload_buddy(e4b);
1812
1813 return 0;
1814 }
1815
1816 static noinline_for_stack
ext4_mb_find_by_goal(struct ext4_allocation_context * ac,struct ext4_buddy * e4b)1817 int ext4_mb_find_by_goal(struct ext4_allocation_context *ac,
1818 struct ext4_buddy *e4b)
1819 {
1820 ext4_group_t group = ac->ac_g_ex.fe_group;
1821 int max;
1822 int err;
1823 struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
1824 struct ext4_group_info *grp = ext4_get_group_info(ac->ac_sb, group);
1825 struct ext4_free_extent ex;
1826
1827 if (!(ac->ac_flags & EXT4_MB_HINT_TRY_GOAL))
1828 return 0;
1829 if (grp->bb_free == 0)
1830 return 0;
1831
1832 err = ext4_mb_load_buddy(ac->ac_sb, group, e4b);
1833 if (err)
1834 return err;
1835
1836 if (unlikely(EXT4_MB_GRP_BBITMAP_CORRUPT(e4b->bd_info))) {
1837 ext4_mb_unload_buddy(e4b);
1838 return 0;
1839 }
1840
1841 ext4_lock_group(ac->ac_sb, group);
1842 max = mb_find_extent(e4b, ac->ac_g_ex.fe_start,
1843 ac->ac_g_ex.fe_len, &ex);
1844 ex.fe_logical = 0xDEADFA11; /* debug value */
1845
1846 if (max >= ac->ac_g_ex.fe_len && ac->ac_g_ex.fe_len == sbi->s_stripe) {
1847 ext4_fsblk_t start;
1848
1849 start = ext4_group_first_block_no(ac->ac_sb, e4b->bd_group) +
1850 ex.fe_start;
1851 /* use do_div to get remainder (would be 64-bit modulo) */
1852 if (do_div(start, sbi->s_stripe) == 0) {
1853 ac->ac_found++;
1854 ac->ac_b_ex = ex;
1855 ext4_mb_use_best_found(ac, e4b);
1856 }
1857 } else if (max >= ac->ac_g_ex.fe_len) {
1858 BUG_ON(ex.fe_len <= 0);
1859 BUG_ON(ex.fe_group != ac->ac_g_ex.fe_group);
1860 BUG_ON(ex.fe_start != ac->ac_g_ex.fe_start);
1861 ac->ac_found++;
1862 ac->ac_b_ex = ex;
1863 ext4_mb_use_best_found(ac, e4b);
1864 } else if (max > 0 && (ac->ac_flags & EXT4_MB_HINT_MERGE)) {
1865 /* Sometimes, caller may want to merge even small
1866 * number of blocks to an existing extent */
1867 BUG_ON(ex.fe_len <= 0);
1868 BUG_ON(ex.fe_group != ac->ac_g_ex.fe_group);
1869 BUG_ON(ex.fe_start != ac->ac_g_ex.fe_start);
1870 ac->ac_found++;
1871 ac->ac_b_ex = ex;
1872 ext4_mb_use_best_found(ac, e4b);
1873 }
1874 ext4_unlock_group(ac->ac_sb, group);
1875 ext4_mb_unload_buddy(e4b);
1876
1877 return 0;
1878 }
1879
1880 /*
1881 * The routine scans buddy structures (not bitmap!) from given order
1882 * to max order and tries to find big enough chunk to satisfy the req
1883 */
1884 static noinline_for_stack
ext4_mb_simple_scan_group(struct ext4_allocation_context * ac,struct ext4_buddy * e4b)1885 void ext4_mb_simple_scan_group(struct ext4_allocation_context *ac,
1886 struct ext4_buddy *e4b)
1887 {
1888 struct super_block *sb = ac->ac_sb;
1889 struct ext4_group_info *grp = e4b->bd_info;
1890 void *buddy;
1891 int i;
1892 int k;
1893 int max;
1894
1895 BUG_ON(ac->ac_2order <= 0);
1896 for (i = ac->ac_2order; i <= sb->s_blocksize_bits + 1; i++) {
1897 if (grp->bb_counters[i] == 0)
1898 continue;
1899
1900 buddy = mb_find_buddy(e4b, i, &max);
1901 BUG_ON(buddy == NULL);
1902
1903 k = mb_find_next_zero_bit(buddy, max, 0);
1904 BUG_ON(k >= max);
1905
1906 ac->ac_found++;
1907
1908 ac->ac_b_ex.fe_len = 1 << i;
1909 ac->ac_b_ex.fe_start = k << i;
1910 ac->ac_b_ex.fe_group = e4b->bd_group;
1911
1912 ext4_mb_use_best_found(ac, e4b);
1913
1914 BUG_ON(ac->ac_b_ex.fe_len != ac->ac_g_ex.fe_len);
1915
1916 if (EXT4_SB(sb)->s_mb_stats)
1917 atomic_inc(&EXT4_SB(sb)->s_bal_2orders);
1918
1919 break;
1920 }
1921 }
1922
1923 /*
1924 * The routine scans the group and measures all found extents.
1925 * In order to optimize scanning, caller must pass number of
1926 * free blocks in the group, so the routine can know upper limit.
1927 */
1928 static noinline_for_stack
ext4_mb_complex_scan_group(struct ext4_allocation_context * ac,struct ext4_buddy * e4b)1929 void ext4_mb_complex_scan_group(struct ext4_allocation_context *ac,
1930 struct ext4_buddy *e4b)
1931 {
1932 struct super_block *sb = ac->ac_sb;
1933 void *bitmap = e4b->bd_bitmap;
1934 struct ext4_free_extent ex;
1935 int i;
1936 int free;
1937
1938 free = e4b->bd_info->bb_free;
1939 BUG_ON(free <= 0);
1940
1941 i = e4b->bd_info->bb_first_free;
1942
1943 while (free && ac->ac_status == AC_STATUS_CONTINUE) {
1944 i = mb_find_next_zero_bit(bitmap,
1945 EXT4_CLUSTERS_PER_GROUP(sb), i);
1946 if (i >= EXT4_CLUSTERS_PER_GROUP(sb)) {
1947 /*
1948 * IF we have corrupt bitmap, we won't find any
1949 * free blocks even though group info says we
1950 * we have free blocks
1951 */
1952 ext4_grp_locked_error(sb, e4b->bd_group, 0, 0,
1953 "%d free clusters as per "
1954 "group info. But bitmap says 0",
1955 free);
1956 break;
1957 }
1958
1959 mb_find_extent(e4b, i, ac->ac_g_ex.fe_len, &ex);
1960 BUG_ON(ex.fe_len <= 0);
1961 if (free < ex.fe_len) {
1962 ext4_grp_locked_error(sb, e4b->bd_group, 0, 0,
1963 "%d free clusters as per "
1964 "group info. But got %d blocks",
1965 free, ex.fe_len);
1966 /*
1967 * The number of free blocks differs. This mostly
1968 * indicate that the bitmap is corrupt. So exit
1969 * without claiming the space.
1970 */
1971 break;
1972 }
1973 ex.fe_logical = 0xDEADC0DE; /* debug value */
1974 ext4_mb_measure_extent(ac, &ex, e4b);
1975
1976 i += ex.fe_len;
1977 free -= ex.fe_len;
1978 }
1979
1980 ext4_mb_check_limits(ac, e4b, 1);
1981 }
1982
1983 /*
1984 * This is a special case for storages like raid5
1985 * we try to find stripe-aligned chunks for stripe-size-multiple requests
1986 */
1987 static noinline_for_stack
ext4_mb_scan_aligned(struct ext4_allocation_context * ac,struct ext4_buddy * e4b)1988 void ext4_mb_scan_aligned(struct ext4_allocation_context *ac,
1989 struct ext4_buddy *e4b)
1990 {
1991 struct super_block *sb = ac->ac_sb;
1992 struct ext4_sb_info *sbi = EXT4_SB(sb);
1993 void *bitmap = e4b->bd_bitmap;
1994 struct ext4_free_extent ex;
1995 ext4_fsblk_t first_group_block;
1996 ext4_fsblk_t a;
1997 ext4_grpblk_t i;
1998 int max;
1999
2000 BUG_ON(sbi->s_stripe == 0);
2001
2002 /* find first stripe-aligned block in group */
2003 first_group_block = ext4_group_first_block_no(sb, e4b->bd_group);
2004
2005 a = first_group_block + sbi->s_stripe - 1;
2006 do_div(a, sbi->s_stripe);
2007 i = (a * sbi->s_stripe) - first_group_block;
2008
2009 while (i < EXT4_CLUSTERS_PER_GROUP(sb)) {
2010 if (!mb_test_bit(i, bitmap)) {
2011 max = mb_find_extent(e4b, i, sbi->s_stripe, &ex);
2012 if (max >= sbi->s_stripe) {
2013 ac->ac_found++;
2014 ex.fe_logical = 0xDEADF00D; /* debug value */
2015 ac->ac_b_ex = ex;
2016 ext4_mb_use_best_found(ac, e4b);
2017 break;
2018 }
2019 }
2020 i += sbi->s_stripe;
2021 }
2022 }
2023
2024 /*
2025 * This is now called BEFORE we load the buddy bitmap.
2026 * Returns either 1 or 0 indicating that the group is either suitable
2027 * for the allocation or not. In addition it can also return negative
2028 * error code when something goes wrong.
2029 */
ext4_mb_good_group(struct ext4_allocation_context * ac,ext4_group_t group,int cr)2030 static int ext4_mb_good_group(struct ext4_allocation_context *ac,
2031 ext4_group_t group, int cr)
2032 {
2033 unsigned free, fragments;
2034 int flex_size = ext4_flex_bg_size(EXT4_SB(ac->ac_sb));
2035 struct ext4_group_info *grp = ext4_get_group_info(ac->ac_sb, group);
2036
2037 BUG_ON(cr < 0 || cr >= 4);
2038
2039 free = grp->bb_free;
2040 if (free == 0)
2041 return 0;
2042 if (cr <= 2 && free < ac->ac_g_ex.fe_len)
2043 return 0;
2044
2045 if (unlikely(EXT4_MB_GRP_BBITMAP_CORRUPT(grp)))
2046 return 0;
2047
2048 /* We only do this if the grp has never been initialized */
2049 if (unlikely(EXT4_MB_GRP_NEED_INIT(grp))) {
2050 int ret = ext4_mb_init_group(ac->ac_sb, group);
2051 if (ret)
2052 return ret;
2053 }
2054
2055 fragments = grp->bb_fragments;
2056 if (fragments == 0)
2057 return 0;
2058
2059 switch (cr) {
2060 case 0:
2061 BUG_ON(ac->ac_2order == 0);
2062
2063 /* Avoid using the first bg of a flexgroup for data files */
2064 if ((ac->ac_flags & EXT4_MB_HINT_DATA) &&
2065 (flex_size >= EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME) &&
2066 ((group % flex_size) == 0))
2067 return 0;
2068
2069 if ((ac->ac_2order > ac->ac_sb->s_blocksize_bits+1) ||
2070 (free / fragments) >= ac->ac_g_ex.fe_len)
2071 return 1;
2072
2073 if (grp->bb_largest_free_order < ac->ac_2order)
2074 return 0;
2075
2076 return 1;
2077 case 1:
2078 if ((free / fragments) >= ac->ac_g_ex.fe_len)
2079 return 1;
2080 break;
2081 case 2:
2082 if (free >= ac->ac_g_ex.fe_len)
2083 return 1;
2084 break;
2085 case 3:
2086 return 1;
2087 default:
2088 BUG();
2089 }
2090
2091 return 0;
2092 }
2093
2094 static noinline_for_stack int
ext4_mb_regular_allocator(struct ext4_allocation_context * ac)2095 ext4_mb_regular_allocator(struct ext4_allocation_context *ac)
2096 {
2097 ext4_group_t ngroups, group, i;
2098 int cr;
2099 int err = 0, first_err = 0;
2100 struct ext4_sb_info *sbi;
2101 struct super_block *sb;
2102 struct ext4_buddy e4b;
2103
2104 sb = ac->ac_sb;
2105 sbi = EXT4_SB(sb);
2106 ngroups = ext4_get_groups_count(sb);
2107 /* non-extent files are limited to low blocks/groups */
2108 if (!(ext4_test_inode_flag(ac->ac_inode, EXT4_INODE_EXTENTS)))
2109 ngroups = sbi->s_blockfile_groups;
2110
2111 BUG_ON(ac->ac_status == AC_STATUS_FOUND);
2112
2113 /* first, try the goal */
2114 err = ext4_mb_find_by_goal(ac, &e4b);
2115 if (err || ac->ac_status == AC_STATUS_FOUND)
2116 goto out;
2117
2118 if (unlikely(ac->ac_flags & EXT4_MB_HINT_GOAL_ONLY))
2119 goto out;
2120
2121 /*
2122 * ac->ac2_order is set only if the fe_len is a power of 2
2123 * if ac2_order is set we also set criteria to 0 so that we
2124 * try exact allocation using buddy.
2125 */
2126 i = fls(ac->ac_g_ex.fe_len);
2127 ac->ac_2order = 0;
2128 /*
2129 * We search using buddy data only if the order of the request
2130 * is greater than equal to the sbi_s_mb_order2_reqs
2131 * You can tune it via /sys/fs/ext4/<partition>/mb_order2_req
2132 */
2133 if (i >= sbi->s_mb_order2_reqs) {
2134 /*
2135 * This should tell if fe_len is exactly power of 2
2136 */
2137 if ((ac->ac_g_ex.fe_len & (~(1 << (i - 1)))) == 0)
2138 ac->ac_2order = i - 1;
2139 }
2140
2141 /* if stream allocation is enabled, use global goal */
2142 if (ac->ac_flags & EXT4_MB_STREAM_ALLOC) {
2143 /* TBD: may be hot point */
2144 spin_lock(&sbi->s_md_lock);
2145 ac->ac_g_ex.fe_group = sbi->s_mb_last_group;
2146 ac->ac_g_ex.fe_start = sbi->s_mb_last_start;
2147 spin_unlock(&sbi->s_md_lock);
2148 }
2149
2150 /* Let's just scan groups to find more-less suitable blocks */
2151 cr = ac->ac_2order ? 0 : 1;
2152 /*
2153 * cr == 0 try to get exact allocation,
2154 * cr == 3 try to get anything
2155 */
2156 repeat:
2157 for (; cr < 4 && ac->ac_status == AC_STATUS_CONTINUE; cr++) {
2158 ac->ac_criteria = cr;
2159 /*
2160 * searching for the right group start
2161 * from the goal value specified
2162 */
2163 group = ac->ac_g_ex.fe_group;
2164
2165 for (i = 0; i < ngroups; group++, i++) {
2166 int ret = 0;
2167 cond_resched();
2168 /*
2169 * Artificially restricted ngroups for non-extent
2170 * files makes group > ngroups possible on first loop.
2171 */
2172 if (group >= ngroups)
2173 group = 0;
2174
2175 /* This now checks without needing the buddy page */
2176 ret = ext4_mb_good_group(ac, group, cr);
2177 if (ret <= 0) {
2178 if (!first_err)
2179 first_err = ret;
2180 continue;
2181 }
2182
2183 err = ext4_mb_load_buddy(sb, group, &e4b);
2184 if (err)
2185 goto out;
2186
2187 ext4_lock_group(sb, group);
2188
2189 /*
2190 * We need to check again after locking the
2191 * block group
2192 */
2193 ret = ext4_mb_good_group(ac, group, cr);
2194 if (ret <= 0) {
2195 ext4_unlock_group(sb, group);
2196 ext4_mb_unload_buddy(&e4b);
2197 if (!first_err)
2198 first_err = ret;
2199 continue;
2200 }
2201
2202 ac->ac_groups_scanned++;
2203 if (cr == 0 && ac->ac_2order < sb->s_blocksize_bits+2)
2204 ext4_mb_simple_scan_group(ac, &e4b);
2205 else if (cr == 1 && sbi->s_stripe &&
2206 !(ac->ac_g_ex.fe_len % sbi->s_stripe))
2207 ext4_mb_scan_aligned(ac, &e4b);
2208 else
2209 ext4_mb_complex_scan_group(ac, &e4b);
2210
2211 ext4_unlock_group(sb, group);
2212 ext4_mb_unload_buddy(&e4b);
2213
2214 if (ac->ac_status != AC_STATUS_CONTINUE)
2215 break;
2216 }
2217 }
2218
2219 if (ac->ac_b_ex.fe_len > 0 && ac->ac_status != AC_STATUS_FOUND &&
2220 !(ac->ac_flags & EXT4_MB_HINT_FIRST)) {
2221 /*
2222 * We've been searching too long. Let's try to allocate
2223 * the best chunk we've found so far
2224 */
2225
2226 ext4_mb_try_best_found(ac, &e4b);
2227 if (ac->ac_status != AC_STATUS_FOUND) {
2228 /*
2229 * Someone more lucky has already allocated it.
2230 * The only thing we can do is just take first
2231 * found block(s)
2232 printk(KERN_DEBUG "EXT4-fs: someone won our chunk\n");
2233 */
2234 ac->ac_b_ex.fe_group = 0;
2235 ac->ac_b_ex.fe_start = 0;
2236 ac->ac_b_ex.fe_len = 0;
2237 ac->ac_status = AC_STATUS_CONTINUE;
2238 ac->ac_flags |= EXT4_MB_HINT_FIRST;
2239 cr = 3;
2240 atomic_inc(&sbi->s_mb_lost_chunks);
2241 goto repeat;
2242 }
2243 }
2244 out:
2245 if (!err && ac->ac_status != AC_STATUS_FOUND && first_err)
2246 err = first_err;
2247 return err;
2248 }
2249
ext4_mb_seq_groups_start(struct seq_file * seq,loff_t * pos)2250 static void *ext4_mb_seq_groups_start(struct seq_file *seq, loff_t *pos)
2251 {
2252 struct super_block *sb = seq->private;
2253 ext4_group_t group;
2254
2255 if (*pos < 0 || *pos >= ext4_get_groups_count(sb))
2256 return NULL;
2257 group = *pos + 1;
2258 return (void *) ((unsigned long) group);
2259 }
2260
ext4_mb_seq_groups_next(struct seq_file * seq,void * v,loff_t * pos)2261 static void *ext4_mb_seq_groups_next(struct seq_file *seq, void *v, loff_t *pos)
2262 {
2263 struct super_block *sb = seq->private;
2264 ext4_group_t group;
2265
2266 ++*pos;
2267 if (*pos < 0 || *pos >= ext4_get_groups_count(sb))
2268 return NULL;
2269 group = *pos + 1;
2270 return (void *) ((unsigned long) group);
2271 }
2272
ext4_mb_seq_groups_show(struct seq_file * seq,void * v)2273 static int ext4_mb_seq_groups_show(struct seq_file *seq, void *v)
2274 {
2275 struct super_block *sb = seq->private;
2276 ext4_group_t group = (ext4_group_t) ((unsigned long) v);
2277 int i;
2278 int err, buddy_loaded = 0;
2279 struct ext4_buddy e4b;
2280 struct ext4_group_info *grinfo;
2281 struct sg {
2282 struct ext4_group_info info;
2283 ext4_grpblk_t counters[16];
2284 } sg;
2285
2286 group--;
2287 if (group == 0)
2288 seq_puts(seq, "#group: free frags first ["
2289 " 2^0 2^1 2^2 2^3 2^4 2^5 2^6 "
2290 " 2^7 2^8 2^9 2^10 2^11 2^12 2^13 ]");
2291
2292 i = (sb->s_blocksize_bits + 2) * sizeof(sg.info.bb_counters[0]) +
2293 sizeof(struct ext4_group_info);
2294 grinfo = ext4_get_group_info(sb, group);
2295 /* Load the group info in memory only if not already loaded. */
2296 if (unlikely(EXT4_MB_GRP_NEED_INIT(grinfo))) {
2297 err = ext4_mb_load_buddy(sb, group, &e4b);
2298 if (err) {
2299 seq_printf(seq, "#%-5u: I/O error\n", group);
2300 return 0;
2301 }
2302 buddy_loaded = 1;
2303 }
2304
2305 memcpy(&sg, ext4_get_group_info(sb, group), i);
2306
2307 if (buddy_loaded)
2308 ext4_mb_unload_buddy(&e4b);
2309
2310 seq_printf(seq, "#%-5u: %-5u %-5u %-5u [", group, sg.info.bb_free,
2311 sg.info.bb_fragments, sg.info.bb_first_free);
2312 for (i = 0; i <= 13; i++)
2313 seq_printf(seq, " %-5u", i <= sb->s_blocksize_bits + 1 ?
2314 sg.info.bb_counters[i] : 0);
2315 seq_printf(seq, " ]\n");
2316
2317 return 0;
2318 }
2319
ext4_mb_seq_groups_stop(struct seq_file * seq,void * v)2320 static void ext4_mb_seq_groups_stop(struct seq_file *seq, void *v)
2321 {
2322 }
2323
2324 static const struct seq_operations ext4_mb_seq_groups_ops = {
2325 .start = ext4_mb_seq_groups_start,
2326 .next = ext4_mb_seq_groups_next,
2327 .stop = ext4_mb_seq_groups_stop,
2328 .show = ext4_mb_seq_groups_show,
2329 };
2330
ext4_mb_seq_groups_open(struct inode * inode,struct file * file)2331 static int ext4_mb_seq_groups_open(struct inode *inode, struct file *file)
2332 {
2333 struct super_block *sb = PDE_DATA(inode);
2334 int rc;
2335
2336 rc = seq_open(file, &ext4_mb_seq_groups_ops);
2337 if (rc == 0) {
2338 struct seq_file *m = file->private_data;
2339 m->private = sb;
2340 }
2341 return rc;
2342
2343 }
2344
2345 const struct file_operations ext4_seq_mb_groups_fops = {
2346 .owner = THIS_MODULE,
2347 .open = ext4_mb_seq_groups_open,
2348 .read = seq_read,
2349 .llseek = seq_lseek,
2350 .release = seq_release,
2351 };
2352
get_groupinfo_cache(int blocksize_bits)2353 static struct kmem_cache *get_groupinfo_cache(int blocksize_bits)
2354 {
2355 int cache_index = blocksize_bits - EXT4_MIN_BLOCK_LOG_SIZE;
2356 struct kmem_cache *cachep = ext4_groupinfo_caches[cache_index];
2357
2358 BUG_ON(!cachep);
2359 return cachep;
2360 }
2361
2362 /*
2363 * Allocate the top-level s_group_info array for the specified number
2364 * of groups
2365 */
ext4_mb_alloc_groupinfo(struct super_block * sb,ext4_group_t ngroups)2366 int ext4_mb_alloc_groupinfo(struct super_block *sb, ext4_group_t ngroups)
2367 {
2368 struct ext4_sb_info *sbi = EXT4_SB(sb);
2369 unsigned size;
2370 struct ext4_group_info ***new_groupinfo;
2371
2372 size = (ngroups + EXT4_DESC_PER_BLOCK(sb) - 1) >>
2373 EXT4_DESC_PER_BLOCK_BITS(sb);
2374 if (size <= sbi->s_group_info_size)
2375 return 0;
2376
2377 size = roundup_pow_of_two(sizeof(*sbi->s_group_info) * size);
2378 new_groupinfo = ext4_kvzalloc(size, GFP_KERNEL);
2379 if (!new_groupinfo) {
2380 ext4_msg(sb, KERN_ERR, "can't allocate buddy meta group");
2381 return -ENOMEM;
2382 }
2383 if (sbi->s_group_info) {
2384 memcpy(new_groupinfo, sbi->s_group_info,
2385 sbi->s_group_info_size * sizeof(*sbi->s_group_info));
2386 kvfree(sbi->s_group_info);
2387 }
2388 sbi->s_group_info = new_groupinfo;
2389 sbi->s_group_info_size = size / sizeof(*sbi->s_group_info);
2390 ext4_debug("allocated s_groupinfo array for %d meta_bg's\n",
2391 sbi->s_group_info_size);
2392 return 0;
2393 }
2394
2395 /* Create and initialize ext4_group_info data for the given group. */
ext4_mb_add_groupinfo(struct super_block * sb,ext4_group_t group,struct ext4_group_desc * desc)2396 int ext4_mb_add_groupinfo(struct super_block *sb, ext4_group_t group,
2397 struct ext4_group_desc *desc)
2398 {
2399 int i;
2400 int metalen = 0;
2401 struct ext4_sb_info *sbi = EXT4_SB(sb);
2402 struct ext4_group_info **meta_group_info;
2403 struct kmem_cache *cachep = get_groupinfo_cache(sb->s_blocksize_bits);
2404
2405 /*
2406 * First check if this group is the first of a reserved block.
2407 * If it's true, we have to allocate a new table of pointers
2408 * to ext4_group_info structures
2409 */
2410 if (group % EXT4_DESC_PER_BLOCK(sb) == 0) {
2411 metalen = sizeof(*meta_group_info) <<
2412 EXT4_DESC_PER_BLOCK_BITS(sb);
2413 meta_group_info = kmalloc(metalen, GFP_NOFS);
2414 if (meta_group_info == NULL) {
2415 ext4_msg(sb, KERN_ERR, "can't allocate mem "
2416 "for a buddy group");
2417 goto exit_meta_group_info;
2418 }
2419 sbi->s_group_info[group >> EXT4_DESC_PER_BLOCK_BITS(sb)] =
2420 meta_group_info;
2421 }
2422
2423 meta_group_info =
2424 sbi->s_group_info[group >> EXT4_DESC_PER_BLOCK_BITS(sb)];
2425 i = group & (EXT4_DESC_PER_BLOCK(sb) - 1);
2426
2427 meta_group_info[i] = kmem_cache_zalloc(cachep, GFP_NOFS);
2428 if (meta_group_info[i] == NULL) {
2429 ext4_msg(sb, KERN_ERR, "can't allocate buddy mem");
2430 goto exit_group_info;
2431 }
2432 set_bit(EXT4_GROUP_INFO_NEED_INIT_BIT,
2433 &(meta_group_info[i]->bb_state));
2434
2435 /*
2436 * initialize bb_free to be able to skip
2437 * empty groups without initialization
2438 */
2439 if (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
2440 meta_group_info[i]->bb_free =
2441 ext4_free_clusters_after_init(sb, group, desc);
2442 } else {
2443 meta_group_info[i]->bb_free =
2444 ext4_free_group_clusters(sb, desc);
2445 }
2446
2447 INIT_LIST_HEAD(&meta_group_info[i]->bb_prealloc_list);
2448 init_rwsem(&meta_group_info[i]->alloc_sem);
2449 meta_group_info[i]->bb_free_root = RB_ROOT;
2450 meta_group_info[i]->bb_largest_free_order = -1; /* uninit */
2451
2452 #ifdef DOUBLE_CHECK
2453 {
2454 struct buffer_head *bh;
2455 meta_group_info[i]->bb_bitmap =
2456 kmalloc(sb->s_blocksize, GFP_NOFS);
2457 BUG_ON(meta_group_info[i]->bb_bitmap == NULL);
2458 bh = ext4_read_block_bitmap(sb, group);
2459 BUG_ON(IS_ERR_OR_NULL(bh));
2460 memcpy(meta_group_info[i]->bb_bitmap, bh->b_data,
2461 sb->s_blocksize);
2462 put_bh(bh);
2463 }
2464 #endif
2465
2466 return 0;
2467
2468 exit_group_info:
2469 /* If a meta_group_info table has been allocated, release it now */
2470 if (group % EXT4_DESC_PER_BLOCK(sb) == 0) {
2471 kfree(sbi->s_group_info[group >> EXT4_DESC_PER_BLOCK_BITS(sb)]);
2472 sbi->s_group_info[group >> EXT4_DESC_PER_BLOCK_BITS(sb)] = NULL;
2473 }
2474 exit_meta_group_info:
2475 return -ENOMEM;
2476 } /* ext4_mb_add_groupinfo */
2477
ext4_mb_init_backend(struct super_block * sb)2478 static int ext4_mb_init_backend(struct super_block *sb)
2479 {
2480 ext4_group_t ngroups = ext4_get_groups_count(sb);
2481 ext4_group_t i;
2482 struct ext4_sb_info *sbi = EXT4_SB(sb);
2483 int err;
2484 struct ext4_group_desc *desc;
2485 struct kmem_cache *cachep;
2486
2487 err = ext4_mb_alloc_groupinfo(sb, ngroups);
2488 if (err)
2489 return err;
2490
2491 sbi->s_buddy_cache = new_inode(sb);
2492 if (sbi->s_buddy_cache == NULL) {
2493 ext4_msg(sb, KERN_ERR, "can't get new inode");
2494 goto err_freesgi;
2495 }
2496 /* To avoid potentially colliding with an valid on-disk inode number,
2497 * use EXT4_BAD_INO for the buddy cache inode number. This inode is
2498 * not in the inode hash, so it should never be found by iget(), but
2499 * this will avoid confusion if it ever shows up during debugging. */
2500 sbi->s_buddy_cache->i_ino = EXT4_BAD_INO;
2501 EXT4_I(sbi->s_buddy_cache)->i_disksize = 0;
2502 for (i = 0; i < ngroups; i++) {
2503 desc = ext4_get_group_desc(sb, i, NULL);
2504 if (desc == NULL) {
2505 ext4_msg(sb, KERN_ERR, "can't read descriptor %u", i);
2506 goto err_freebuddy;
2507 }
2508 if (ext4_mb_add_groupinfo(sb, i, desc) != 0)
2509 goto err_freebuddy;
2510 }
2511
2512 return 0;
2513
2514 err_freebuddy:
2515 cachep = get_groupinfo_cache(sb->s_blocksize_bits);
2516 while (i-- > 0)
2517 kmem_cache_free(cachep, ext4_get_group_info(sb, i));
2518 i = sbi->s_group_info_size;
2519 while (i-- > 0)
2520 kfree(sbi->s_group_info[i]);
2521 iput(sbi->s_buddy_cache);
2522 err_freesgi:
2523 kvfree(sbi->s_group_info);
2524 return -ENOMEM;
2525 }
2526
ext4_groupinfo_destroy_slabs(void)2527 static void ext4_groupinfo_destroy_slabs(void)
2528 {
2529 int i;
2530
2531 for (i = 0; i < NR_GRPINFO_CACHES; i++) {
2532 if (ext4_groupinfo_caches[i])
2533 kmem_cache_destroy(ext4_groupinfo_caches[i]);
2534 ext4_groupinfo_caches[i] = NULL;
2535 }
2536 }
2537
ext4_groupinfo_create_slab(size_t size)2538 static int ext4_groupinfo_create_slab(size_t size)
2539 {
2540 static DEFINE_MUTEX(ext4_grpinfo_slab_create_mutex);
2541 int slab_size;
2542 int blocksize_bits = order_base_2(size);
2543 int cache_index = blocksize_bits - EXT4_MIN_BLOCK_LOG_SIZE;
2544 struct kmem_cache *cachep;
2545
2546 if (cache_index >= NR_GRPINFO_CACHES)
2547 return -EINVAL;
2548
2549 if (unlikely(cache_index < 0))
2550 cache_index = 0;
2551
2552 mutex_lock(&ext4_grpinfo_slab_create_mutex);
2553 if (ext4_groupinfo_caches[cache_index]) {
2554 mutex_unlock(&ext4_grpinfo_slab_create_mutex);
2555 return 0; /* Already created */
2556 }
2557
2558 slab_size = offsetof(struct ext4_group_info,
2559 bb_counters[blocksize_bits + 2]);
2560
2561 cachep = kmem_cache_create(ext4_groupinfo_slab_names[cache_index],
2562 slab_size, 0, SLAB_RECLAIM_ACCOUNT,
2563 NULL);
2564
2565 ext4_groupinfo_caches[cache_index] = cachep;
2566
2567 mutex_unlock(&ext4_grpinfo_slab_create_mutex);
2568 if (!cachep) {
2569 printk(KERN_EMERG
2570 "EXT4-fs: no memory for groupinfo slab cache\n");
2571 return -ENOMEM;
2572 }
2573
2574 return 0;
2575 }
2576
ext4_mb_init(struct super_block * sb)2577 int ext4_mb_init(struct super_block *sb)
2578 {
2579 struct ext4_sb_info *sbi = EXT4_SB(sb);
2580 unsigned i, j;
2581 unsigned offset, offset_incr;
2582 unsigned max;
2583 int ret;
2584
2585 i = (sb->s_blocksize_bits + 2) * sizeof(*sbi->s_mb_offsets);
2586
2587 sbi->s_mb_offsets = kmalloc(i, GFP_KERNEL);
2588 if (sbi->s_mb_offsets == NULL) {
2589 ret = -ENOMEM;
2590 goto out;
2591 }
2592
2593 i = (sb->s_blocksize_bits + 2) * sizeof(*sbi->s_mb_maxs);
2594 sbi->s_mb_maxs = kmalloc(i, GFP_KERNEL);
2595 if (sbi->s_mb_maxs == NULL) {
2596 ret = -ENOMEM;
2597 goto out;
2598 }
2599
2600 ret = ext4_groupinfo_create_slab(sb->s_blocksize);
2601 if (ret < 0)
2602 goto out;
2603
2604 /* order 0 is regular bitmap */
2605 sbi->s_mb_maxs[0] = sb->s_blocksize << 3;
2606 sbi->s_mb_offsets[0] = 0;
2607
2608 i = 1;
2609 offset = 0;
2610 offset_incr = 1 << (sb->s_blocksize_bits - 1);
2611 max = sb->s_blocksize << 2;
2612 do {
2613 sbi->s_mb_offsets[i] = offset;
2614 sbi->s_mb_maxs[i] = max;
2615 offset += offset_incr;
2616 offset_incr = offset_incr >> 1;
2617 max = max >> 1;
2618 i++;
2619 } while (i <= sb->s_blocksize_bits + 1);
2620
2621 spin_lock_init(&sbi->s_md_lock);
2622 spin_lock_init(&sbi->s_bal_lock);
2623
2624 sbi->s_mb_max_to_scan = MB_DEFAULT_MAX_TO_SCAN;
2625 sbi->s_mb_min_to_scan = MB_DEFAULT_MIN_TO_SCAN;
2626 sbi->s_mb_stats = MB_DEFAULT_STATS;
2627 sbi->s_mb_stream_request = MB_DEFAULT_STREAM_THRESHOLD;
2628 sbi->s_mb_order2_reqs = MB_DEFAULT_ORDER2_REQS;
2629 /*
2630 * The default group preallocation is 512, which for 4k block
2631 * sizes translates to 2 megabytes. However for bigalloc file
2632 * systems, this is probably too big (i.e, if the cluster size
2633 * is 1 megabyte, then group preallocation size becomes half a
2634 * gigabyte!). As a default, we will keep a two megabyte
2635 * group pralloc size for cluster sizes up to 64k, and after
2636 * that, we will force a minimum group preallocation size of
2637 * 32 clusters. This translates to 8 megs when the cluster
2638 * size is 256k, and 32 megs when the cluster size is 1 meg,
2639 * which seems reasonable as a default.
2640 */
2641 sbi->s_mb_group_prealloc = max(MB_DEFAULT_GROUP_PREALLOC >>
2642 sbi->s_cluster_bits, 32);
2643 /*
2644 * If there is a s_stripe > 1, then we set the s_mb_group_prealloc
2645 * to the lowest multiple of s_stripe which is bigger than
2646 * the s_mb_group_prealloc as determined above. We want
2647 * the preallocation size to be an exact multiple of the
2648 * RAID stripe size so that preallocations don't fragment
2649 * the stripes.
2650 */
2651 if (sbi->s_stripe > 1) {
2652 sbi->s_mb_group_prealloc = roundup(
2653 sbi->s_mb_group_prealloc, sbi->s_stripe);
2654 }
2655
2656 sbi->s_locality_groups = alloc_percpu(struct ext4_locality_group);
2657 if (sbi->s_locality_groups == NULL) {
2658 ret = -ENOMEM;
2659 goto out;
2660 }
2661 for_each_possible_cpu(i) {
2662 struct ext4_locality_group *lg;
2663 lg = per_cpu_ptr(sbi->s_locality_groups, i);
2664 mutex_init(&lg->lg_mutex);
2665 for (j = 0; j < PREALLOC_TB_SIZE; j++)
2666 INIT_LIST_HEAD(&lg->lg_prealloc_list[j]);
2667 spin_lock_init(&lg->lg_prealloc_lock);
2668 }
2669
2670 /* init file for buddy data */
2671 ret = ext4_mb_init_backend(sb);
2672 if (ret != 0)
2673 goto out_free_locality_groups;
2674
2675 return 0;
2676
2677 out_free_locality_groups:
2678 free_percpu(sbi->s_locality_groups);
2679 sbi->s_locality_groups = NULL;
2680 out:
2681 kfree(sbi->s_mb_offsets);
2682 sbi->s_mb_offsets = NULL;
2683 kfree(sbi->s_mb_maxs);
2684 sbi->s_mb_maxs = NULL;
2685 return ret;
2686 }
2687
2688 /* need to called with the ext4 group lock held */
ext4_mb_cleanup_pa(struct ext4_group_info * grp)2689 static void ext4_mb_cleanup_pa(struct ext4_group_info *grp)
2690 {
2691 struct ext4_prealloc_space *pa;
2692 struct list_head *cur, *tmp;
2693 int count = 0;
2694
2695 list_for_each_safe(cur, tmp, &grp->bb_prealloc_list) {
2696 pa = list_entry(cur, struct ext4_prealloc_space, pa_group_list);
2697 list_del(&pa->pa_group_list);
2698 count++;
2699 kmem_cache_free(ext4_pspace_cachep, pa);
2700 }
2701 if (count)
2702 mb_debug(1, "mballoc: %u PAs left\n", count);
2703
2704 }
2705
ext4_mb_release(struct super_block * sb)2706 int ext4_mb_release(struct super_block *sb)
2707 {
2708 ext4_group_t ngroups = ext4_get_groups_count(sb);
2709 ext4_group_t i;
2710 int num_meta_group_infos;
2711 struct ext4_group_info *grinfo;
2712 struct ext4_sb_info *sbi = EXT4_SB(sb);
2713 struct kmem_cache *cachep = get_groupinfo_cache(sb->s_blocksize_bits);
2714
2715 if (sbi->s_group_info) {
2716 for (i = 0; i < ngroups; i++) {
2717 grinfo = ext4_get_group_info(sb, i);
2718 #ifdef DOUBLE_CHECK
2719 kfree(grinfo->bb_bitmap);
2720 #endif
2721 ext4_lock_group(sb, i);
2722 ext4_mb_cleanup_pa(grinfo);
2723 ext4_unlock_group(sb, i);
2724 kmem_cache_free(cachep, grinfo);
2725 }
2726 num_meta_group_infos = (ngroups +
2727 EXT4_DESC_PER_BLOCK(sb) - 1) >>
2728 EXT4_DESC_PER_BLOCK_BITS(sb);
2729 for (i = 0; i < num_meta_group_infos; i++)
2730 kfree(sbi->s_group_info[i]);
2731 kvfree(sbi->s_group_info);
2732 }
2733 kfree(sbi->s_mb_offsets);
2734 kfree(sbi->s_mb_maxs);
2735 iput(sbi->s_buddy_cache);
2736 if (sbi->s_mb_stats) {
2737 ext4_msg(sb, KERN_INFO,
2738 "mballoc: %u blocks %u reqs (%u success)",
2739 atomic_read(&sbi->s_bal_allocated),
2740 atomic_read(&sbi->s_bal_reqs),
2741 atomic_read(&sbi->s_bal_success));
2742 ext4_msg(sb, KERN_INFO,
2743 "mballoc: %u extents scanned, %u goal hits, "
2744 "%u 2^N hits, %u breaks, %u lost",
2745 atomic_read(&sbi->s_bal_ex_scanned),
2746 atomic_read(&sbi->s_bal_goals),
2747 atomic_read(&sbi->s_bal_2orders),
2748 atomic_read(&sbi->s_bal_breaks),
2749 atomic_read(&sbi->s_mb_lost_chunks));
2750 ext4_msg(sb, KERN_INFO,
2751 "mballoc: %lu generated and it took %Lu",
2752 sbi->s_mb_buddies_generated,
2753 sbi->s_mb_generation_time);
2754 ext4_msg(sb, KERN_INFO,
2755 "mballoc: %u preallocated, %u discarded",
2756 atomic_read(&sbi->s_mb_preallocated),
2757 atomic_read(&sbi->s_mb_discarded));
2758 }
2759
2760 free_percpu(sbi->s_locality_groups);
2761
2762 return 0;
2763 }
2764
ext4_issue_discard(struct super_block * sb,ext4_group_t block_group,ext4_grpblk_t cluster,int count)2765 static inline int ext4_issue_discard(struct super_block *sb,
2766 ext4_group_t block_group, ext4_grpblk_t cluster, int count)
2767 {
2768 ext4_fsblk_t discard_block;
2769
2770 discard_block = (EXT4_C2B(EXT4_SB(sb), cluster) +
2771 ext4_group_first_block_no(sb, block_group));
2772 count = EXT4_C2B(EXT4_SB(sb), count);
2773 trace_ext4_discard_blocks(sb,
2774 (unsigned long long) discard_block, count);
2775 return sb_issue_discard(sb, discard_block, count, GFP_NOFS, 0);
2776 }
2777
2778 /*
2779 * This function is called by the jbd2 layer once the commit has finished,
2780 * so we know we can free the blocks that were released with that commit.
2781 */
ext4_free_data_callback(struct super_block * sb,struct ext4_journal_cb_entry * jce,int rc)2782 static void ext4_free_data_callback(struct super_block *sb,
2783 struct ext4_journal_cb_entry *jce,
2784 int rc)
2785 {
2786 struct ext4_free_data *entry = (struct ext4_free_data *)jce;
2787 struct ext4_buddy e4b;
2788 struct ext4_group_info *db;
2789 int err, count = 0, count2 = 0;
2790
2791 mb_debug(1, "gonna free %u blocks in group %u (0x%p):",
2792 entry->efd_count, entry->efd_group, entry);
2793
2794 if (test_opt(sb, DISCARD)) {
2795 err = ext4_issue_discard(sb, entry->efd_group,
2796 entry->efd_start_cluster,
2797 entry->efd_count);
2798 if (err && err != -EOPNOTSUPP)
2799 ext4_msg(sb, KERN_WARNING, "discard request in"
2800 " group:%d block:%d count:%d failed"
2801 " with %d", entry->efd_group,
2802 entry->efd_start_cluster,
2803 entry->efd_count, err);
2804 }
2805
2806 err = ext4_mb_load_buddy(sb, entry->efd_group, &e4b);
2807 /* we expect to find existing buddy because it's pinned */
2808 BUG_ON(err != 0);
2809
2810
2811 db = e4b.bd_info;
2812 /* there are blocks to put in buddy to make them really free */
2813 count += entry->efd_count;
2814 count2++;
2815 ext4_lock_group(sb, entry->efd_group);
2816 /* Take it out of per group rb tree */
2817 rb_erase(&entry->efd_node, &(db->bb_free_root));
2818 mb_free_blocks(NULL, &e4b, entry->efd_start_cluster, entry->efd_count);
2819
2820 /*
2821 * Clear the trimmed flag for the group so that the next
2822 * ext4_trim_fs can trim it.
2823 * If the volume is mounted with -o discard, online discard
2824 * is supported and the free blocks will be trimmed online.
2825 */
2826 if (!test_opt(sb, DISCARD))
2827 EXT4_MB_GRP_CLEAR_TRIMMED(db);
2828
2829 if (!db->bb_free_root.rb_node) {
2830 /* No more items in the per group rb tree
2831 * balance refcounts from ext4_mb_free_metadata()
2832 */
2833 page_cache_release(e4b.bd_buddy_page);
2834 page_cache_release(e4b.bd_bitmap_page);
2835 }
2836 ext4_unlock_group(sb, entry->efd_group);
2837 kmem_cache_free(ext4_free_data_cachep, entry);
2838 ext4_mb_unload_buddy(&e4b);
2839
2840 mb_debug(1, "freed %u blocks in %u structures\n", count, count2);
2841 }
2842
ext4_init_mballoc(void)2843 int __init ext4_init_mballoc(void)
2844 {
2845 ext4_pspace_cachep = KMEM_CACHE(ext4_prealloc_space,
2846 SLAB_RECLAIM_ACCOUNT);
2847 if (ext4_pspace_cachep == NULL)
2848 return -ENOMEM;
2849
2850 ext4_ac_cachep = KMEM_CACHE(ext4_allocation_context,
2851 SLAB_RECLAIM_ACCOUNT);
2852 if (ext4_ac_cachep == NULL) {
2853 kmem_cache_destroy(ext4_pspace_cachep);
2854 return -ENOMEM;
2855 }
2856
2857 ext4_free_data_cachep = KMEM_CACHE(ext4_free_data,
2858 SLAB_RECLAIM_ACCOUNT);
2859 if (ext4_free_data_cachep == NULL) {
2860 kmem_cache_destroy(ext4_pspace_cachep);
2861 kmem_cache_destroy(ext4_ac_cachep);
2862 return -ENOMEM;
2863 }
2864 return 0;
2865 }
2866
ext4_exit_mballoc(void)2867 void ext4_exit_mballoc(void)
2868 {
2869 /*
2870 * Wait for completion of call_rcu()'s on ext4_pspace_cachep
2871 * before destroying the slab cache.
2872 */
2873 rcu_barrier();
2874 kmem_cache_destroy(ext4_pspace_cachep);
2875 kmem_cache_destroy(ext4_ac_cachep);
2876 kmem_cache_destroy(ext4_free_data_cachep);
2877 ext4_groupinfo_destroy_slabs();
2878 }
2879
2880
2881 /*
2882 * Check quota and mark chosen space (ac->ac_b_ex) non-free in bitmaps
2883 * Returns 0 if success or error code
2884 */
2885 static noinline_for_stack int
ext4_mb_mark_diskspace_used(struct ext4_allocation_context * ac,handle_t * handle,unsigned int reserv_clstrs)2886 ext4_mb_mark_diskspace_used(struct ext4_allocation_context *ac,
2887 handle_t *handle, unsigned int reserv_clstrs)
2888 {
2889 struct buffer_head *bitmap_bh = NULL;
2890 struct ext4_group_desc *gdp;
2891 struct buffer_head *gdp_bh;
2892 struct ext4_sb_info *sbi;
2893 struct super_block *sb;
2894 ext4_fsblk_t block;
2895 int err, len;
2896
2897 BUG_ON(ac->ac_status != AC_STATUS_FOUND);
2898 BUG_ON(ac->ac_b_ex.fe_len <= 0);
2899
2900 sb = ac->ac_sb;
2901 sbi = EXT4_SB(sb);
2902
2903 bitmap_bh = ext4_read_block_bitmap(sb, ac->ac_b_ex.fe_group);
2904 if (IS_ERR(bitmap_bh)) {
2905 err = PTR_ERR(bitmap_bh);
2906 bitmap_bh = NULL;
2907 goto out_err;
2908 }
2909
2910 BUFFER_TRACE(bitmap_bh, "getting write access");
2911 err = ext4_journal_get_write_access(handle, bitmap_bh);
2912 if (err)
2913 goto out_err;
2914
2915 err = -EIO;
2916 gdp = ext4_get_group_desc(sb, ac->ac_b_ex.fe_group, &gdp_bh);
2917 if (!gdp)
2918 goto out_err;
2919
2920 ext4_debug("using block group %u(%d)\n", ac->ac_b_ex.fe_group,
2921 ext4_free_group_clusters(sb, gdp));
2922
2923 BUFFER_TRACE(gdp_bh, "get_write_access");
2924 err = ext4_journal_get_write_access(handle, gdp_bh);
2925 if (err)
2926 goto out_err;
2927
2928 block = ext4_grp_offs_to_block(sb, &ac->ac_b_ex);
2929
2930 len = EXT4_C2B(sbi, ac->ac_b_ex.fe_len);
2931 if (!ext4_data_block_valid(sbi, block, len)) {
2932 ext4_error(sb, "Allocating blocks %llu-%llu which overlap "
2933 "fs metadata", block, block+len);
2934 /* File system mounted not to panic on error
2935 * Fix the bitmap and repeat the block allocation
2936 * We leak some of the blocks here.
2937 */
2938 ext4_lock_group(sb, ac->ac_b_ex.fe_group);
2939 ext4_set_bits(bitmap_bh->b_data, ac->ac_b_ex.fe_start,
2940 ac->ac_b_ex.fe_len);
2941 ext4_unlock_group(sb, ac->ac_b_ex.fe_group);
2942 err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
2943 if (!err)
2944 err = -EAGAIN;
2945 goto out_err;
2946 }
2947
2948 ext4_lock_group(sb, ac->ac_b_ex.fe_group);
2949 #ifdef AGGRESSIVE_CHECK
2950 {
2951 int i;
2952 for (i = 0; i < ac->ac_b_ex.fe_len; i++) {
2953 BUG_ON(mb_test_bit(ac->ac_b_ex.fe_start + i,
2954 bitmap_bh->b_data));
2955 }
2956 }
2957 #endif
2958 ext4_set_bits(bitmap_bh->b_data, ac->ac_b_ex.fe_start,
2959 ac->ac_b_ex.fe_len);
2960 if (gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
2961 gdp->bg_flags &= cpu_to_le16(~EXT4_BG_BLOCK_UNINIT);
2962 ext4_free_group_clusters_set(sb, gdp,
2963 ext4_free_clusters_after_init(sb,
2964 ac->ac_b_ex.fe_group, gdp));
2965 }
2966 len = ext4_free_group_clusters(sb, gdp) - ac->ac_b_ex.fe_len;
2967 ext4_free_group_clusters_set(sb, gdp, len);
2968 ext4_block_bitmap_csum_set(sb, ac->ac_b_ex.fe_group, gdp, bitmap_bh);
2969 ext4_group_desc_csum_set(sb, ac->ac_b_ex.fe_group, gdp);
2970
2971 ext4_unlock_group(sb, ac->ac_b_ex.fe_group);
2972 percpu_counter_sub(&sbi->s_freeclusters_counter, ac->ac_b_ex.fe_len);
2973 /*
2974 * Now reduce the dirty block count also. Should not go negative
2975 */
2976 if (!(ac->ac_flags & EXT4_MB_DELALLOC_RESERVED))
2977 /* release all the reserved blocks if non delalloc */
2978 percpu_counter_sub(&sbi->s_dirtyclusters_counter,
2979 reserv_clstrs);
2980
2981 if (sbi->s_log_groups_per_flex) {
2982 ext4_group_t flex_group = ext4_flex_group(sbi,
2983 ac->ac_b_ex.fe_group);
2984 atomic64_sub(ac->ac_b_ex.fe_len,
2985 &sbi->s_flex_groups[flex_group].free_clusters);
2986 }
2987
2988 err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
2989 if (err)
2990 goto out_err;
2991 err = ext4_handle_dirty_metadata(handle, NULL, gdp_bh);
2992
2993 out_err:
2994 brelse(bitmap_bh);
2995 return err;
2996 }
2997
2998 /*
2999 * here we normalize request for locality group
3000 * Group request are normalized to s_mb_group_prealloc, which goes to
3001 * s_strip if we set the same via mount option.
3002 * s_mb_group_prealloc can be configured via
3003 * /sys/fs/ext4/<partition>/mb_group_prealloc
3004 *
3005 * XXX: should we try to preallocate more than the group has now?
3006 */
ext4_mb_normalize_group_request(struct ext4_allocation_context * ac)3007 static void ext4_mb_normalize_group_request(struct ext4_allocation_context *ac)
3008 {
3009 struct super_block *sb = ac->ac_sb;
3010 struct ext4_locality_group *lg = ac->ac_lg;
3011
3012 BUG_ON(lg == NULL);
3013 ac->ac_g_ex.fe_len = EXT4_SB(sb)->s_mb_group_prealloc;
3014 mb_debug(1, "#%u: goal %u blocks for locality group\n",
3015 current->pid, ac->ac_g_ex.fe_len);
3016 }
3017
3018 /*
3019 * Normalization means making request better in terms of
3020 * size and alignment
3021 */
3022 static noinline_for_stack void
ext4_mb_normalize_request(struct ext4_allocation_context * ac,struct ext4_allocation_request * ar)3023 ext4_mb_normalize_request(struct ext4_allocation_context *ac,
3024 struct ext4_allocation_request *ar)
3025 {
3026 struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
3027 int bsbits, max;
3028 ext4_lblk_t end;
3029 loff_t size, start_off;
3030 loff_t orig_size __maybe_unused;
3031 ext4_lblk_t start;
3032 struct ext4_inode_info *ei = EXT4_I(ac->ac_inode);
3033 struct ext4_prealloc_space *pa;
3034
3035 /* do normalize only data requests, metadata requests
3036 do not need preallocation */
3037 if (!(ac->ac_flags & EXT4_MB_HINT_DATA))
3038 return;
3039
3040 /* sometime caller may want exact blocks */
3041 if (unlikely(ac->ac_flags & EXT4_MB_HINT_GOAL_ONLY))
3042 return;
3043
3044 /* caller may indicate that preallocation isn't
3045 * required (it's a tail, for example) */
3046 if (ac->ac_flags & EXT4_MB_HINT_NOPREALLOC)
3047 return;
3048
3049 if (ac->ac_flags & EXT4_MB_HINT_GROUP_ALLOC) {
3050 ext4_mb_normalize_group_request(ac);
3051 return ;
3052 }
3053
3054 bsbits = ac->ac_sb->s_blocksize_bits;
3055
3056 /* first, let's learn actual file size
3057 * given current request is allocated */
3058 size = ac->ac_o_ex.fe_logical + EXT4_C2B(sbi, ac->ac_o_ex.fe_len);
3059 size = size << bsbits;
3060 if (size < i_size_read(ac->ac_inode))
3061 size = i_size_read(ac->ac_inode);
3062 orig_size = size;
3063
3064 /* max size of free chunks */
3065 max = 2 << bsbits;
3066
3067 #define NRL_CHECK_SIZE(req, size, max, chunk_size) \
3068 (req <= (size) || max <= (chunk_size))
3069
3070 /* first, try to predict filesize */
3071 /* XXX: should this table be tunable? */
3072 start_off = 0;
3073 if (size <= 16 * 1024) {
3074 size = 16 * 1024;
3075 } else if (size <= 32 * 1024) {
3076 size = 32 * 1024;
3077 } else if (size <= 64 * 1024) {
3078 size = 64 * 1024;
3079 } else if (size <= 128 * 1024) {
3080 size = 128 * 1024;
3081 } else if (size <= 256 * 1024) {
3082 size = 256 * 1024;
3083 } else if (size <= 512 * 1024) {
3084 size = 512 * 1024;
3085 } else if (size <= 1024 * 1024) {
3086 size = 1024 * 1024;
3087 } else if (NRL_CHECK_SIZE(size, 4 * 1024 * 1024, max, 2 * 1024)) {
3088 start_off = ((loff_t)ac->ac_o_ex.fe_logical >>
3089 (21 - bsbits)) << 21;
3090 size = 2 * 1024 * 1024;
3091 } else if (NRL_CHECK_SIZE(size, 8 * 1024 * 1024, max, 4 * 1024)) {
3092 start_off = ((loff_t)ac->ac_o_ex.fe_logical >>
3093 (22 - bsbits)) << 22;
3094 size = 4 * 1024 * 1024;
3095 } else if (NRL_CHECK_SIZE(ac->ac_o_ex.fe_len,
3096 (8<<20)>>bsbits, max, 8 * 1024)) {
3097 start_off = ((loff_t)ac->ac_o_ex.fe_logical >>
3098 (23 - bsbits)) << 23;
3099 size = 8 * 1024 * 1024;
3100 } else {
3101 start_off = (loff_t) ac->ac_o_ex.fe_logical << bsbits;
3102 size = (loff_t) EXT4_C2B(EXT4_SB(ac->ac_sb),
3103 ac->ac_o_ex.fe_len) << bsbits;
3104 }
3105 size = size >> bsbits;
3106 start = start_off >> bsbits;
3107
3108 /* don't cover already allocated blocks in selected range */
3109 if (ar->pleft && start <= ar->lleft) {
3110 size -= ar->lleft + 1 - start;
3111 start = ar->lleft + 1;
3112 }
3113 if (ar->pright && start + size - 1 >= ar->lright)
3114 size -= start + size - ar->lright;
3115
3116 end = start + size;
3117
3118 /* check we don't cross already preallocated blocks */
3119 rcu_read_lock();
3120 list_for_each_entry_rcu(pa, &ei->i_prealloc_list, pa_inode_list) {
3121 ext4_lblk_t pa_end;
3122
3123 if (pa->pa_deleted)
3124 continue;
3125 spin_lock(&pa->pa_lock);
3126 if (pa->pa_deleted) {
3127 spin_unlock(&pa->pa_lock);
3128 continue;
3129 }
3130
3131 pa_end = pa->pa_lstart + EXT4_C2B(EXT4_SB(ac->ac_sb),
3132 pa->pa_len);
3133
3134 /* PA must not overlap original request */
3135 BUG_ON(!(ac->ac_o_ex.fe_logical >= pa_end ||
3136 ac->ac_o_ex.fe_logical < pa->pa_lstart));
3137
3138 /* skip PAs this normalized request doesn't overlap with */
3139 if (pa->pa_lstart >= end || pa_end <= start) {
3140 spin_unlock(&pa->pa_lock);
3141 continue;
3142 }
3143 BUG_ON(pa->pa_lstart <= start && pa_end >= end);
3144
3145 /* adjust start or end to be adjacent to this pa */
3146 if (pa_end <= ac->ac_o_ex.fe_logical) {
3147 BUG_ON(pa_end < start);
3148 start = pa_end;
3149 } else if (pa->pa_lstart > ac->ac_o_ex.fe_logical) {
3150 BUG_ON(pa->pa_lstart > end);
3151 end = pa->pa_lstart;
3152 }
3153 spin_unlock(&pa->pa_lock);
3154 }
3155 rcu_read_unlock();
3156 size = end - start;
3157
3158 /* XXX: extra loop to check we really don't overlap preallocations */
3159 rcu_read_lock();
3160 list_for_each_entry_rcu(pa, &ei->i_prealloc_list, pa_inode_list) {
3161 ext4_lblk_t pa_end;
3162
3163 spin_lock(&pa->pa_lock);
3164 if (pa->pa_deleted == 0) {
3165 pa_end = pa->pa_lstart + EXT4_C2B(EXT4_SB(ac->ac_sb),
3166 pa->pa_len);
3167 BUG_ON(!(start >= pa_end || end <= pa->pa_lstart));
3168 }
3169 spin_unlock(&pa->pa_lock);
3170 }
3171 rcu_read_unlock();
3172
3173 if (start + size <= ac->ac_o_ex.fe_logical &&
3174 start > ac->ac_o_ex.fe_logical) {
3175 ext4_msg(ac->ac_sb, KERN_ERR,
3176 "start %lu, size %lu, fe_logical %lu",
3177 (unsigned long) start, (unsigned long) size,
3178 (unsigned long) ac->ac_o_ex.fe_logical);
3179 BUG();
3180 }
3181 BUG_ON(size <= 0 || size > EXT4_BLOCKS_PER_GROUP(ac->ac_sb));
3182
3183 /* now prepare goal request */
3184
3185 /* XXX: is it better to align blocks WRT to logical
3186 * placement or satisfy big request as is */
3187 ac->ac_g_ex.fe_logical = start;
3188 ac->ac_g_ex.fe_len = EXT4_NUM_B2C(sbi, size);
3189
3190 /* define goal start in order to merge */
3191 if (ar->pright && (ar->lright == (start + size))) {
3192 /* merge to the right */
3193 ext4_get_group_no_and_offset(ac->ac_sb, ar->pright - size,
3194 &ac->ac_f_ex.fe_group,
3195 &ac->ac_f_ex.fe_start);
3196 ac->ac_flags |= EXT4_MB_HINT_TRY_GOAL;
3197 }
3198 if (ar->pleft && (ar->lleft + 1 == start)) {
3199 /* merge to the left */
3200 ext4_get_group_no_and_offset(ac->ac_sb, ar->pleft + 1,
3201 &ac->ac_f_ex.fe_group,
3202 &ac->ac_f_ex.fe_start);
3203 ac->ac_flags |= EXT4_MB_HINT_TRY_GOAL;
3204 }
3205
3206 mb_debug(1, "goal: %u(was %u) blocks at %u\n", (unsigned) size,
3207 (unsigned) orig_size, (unsigned) start);
3208 }
3209
ext4_mb_collect_stats(struct ext4_allocation_context * ac)3210 static void ext4_mb_collect_stats(struct ext4_allocation_context *ac)
3211 {
3212 struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
3213
3214 if (sbi->s_mb_stats && ac->ac_g_ex.fe_len > 1) {
3215 atomic_inc(&sbi->s_bal_reqs);
3216 atomic_add(ac->ac_b_ex.fe_len, &sbi->s_bal_allocated);
3217 if (ac->ac_b_ex.fe_len >= ac->ac_o_ex.fe_len)
3218 atomic_inc(&sbi->s_bal_success);
3219 atomic_add(ac->ac_found, &sbi->s_bal_ex_scanned);
3220 if (ac->ac_g_ex.fe_start == ac->ac_b_ex.fe_start &&
3221 ac->ac_g_ex.fe_group == ac->ac_b_ex.fe_group)
3222 atomic_inc(&sbi->s_bal_goals);
3223 if (ac->ac_found > sbi->s_mb_max_to_scan)
3224 atomic_inc(&sbi->s_bal_breaks);
3225 }
3226
3227 if (ac->ac_op == EXT4_MB_HISTORY_ALLOC)
3228 trace_ext4_mballoc_alloc(ac);
3229 else
3230 trace_ext4_mballoc_prealloc(ac);
3231 }
3232
3233 /*
3234 * Called on failure; free up any blocks from the inode PA for this
3235 * context. We don't need this for MB_GROUP_PA because we only change
3236 * pa_free in ext4_mb_release_context(), but on failure, we've already
3237 * zeroed out ac->ac_b_ex.fe_len, so group_pa->pa_free is not changed.
3238 */
ext4_discard_allocated_blocks(struct ext4_allocation_context * ac)3239 static void ext4_discard_allocated_blocks(struct ext4_allocation_context *ac)
3240 {
3241 struct ext4_prealloc_space *pa = ac->ac_pa;
3242 struct ext4_buddy e4b;
3243 int err;
3244
3245 if (pa == NULL) {
3246 if (ac->ac_f_ex.fe_len == 0)
3247 return;
3248 err = ext4_mb_load_buddy(ac->ac_sb, ac->ac_f_ex.fe_group, &e4b);
3249 if (err) {
3250 /*
3251 * This should never happen since we pin the
3252 * pages in the ext4_allocation_context so
3253 * ext4_mb_load_buddy() should never fail.
3254 */
3255 WARN(1, "mb_load_buddy failed (%d)", err);
3256 return;
3257 }
3258 ext4_lock_group(ac->ac_sb, ac->ac_f_ex.fe_group);
3259 mb_free_blocks(ac->ac_inode, &e4b, ac->ac_f_ex.fe_start,
3260 ac->ac_f_ex.fe_len);
3261 ext4_unlock_group(ac->ac_sb, ac->ac_f_ex.fe_group);
3262 ext4_mb_unload_buddy(&e4b);
3263 return;
3264 }
3265 if (pa->pa_type == MB_INODE_PA)
3266 pa->pa_free += ac->ac_b_ex.fe_len;
3267 }
3268
3269 /*
3270 * use blocks preallocated to inode
3271 */
ext4_mb_use_inode_pa(struct ext4_allocation_context * ac,struct ext4_prealloc_space * pa)3272 static void ext4_mb_use_inode_pa(struct ext4_allocation_context *ac,
3273 struct ext4_prealloc_space *pa)
3274 {
3275 struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
3276 ext4_fsblk_t start;
3277 ext4_fsblk_t end;
3278 int len;
3279
3280 /* found preallocated blocks, use them */
3281 start = pa->pa_pstart + (ac->ac_o_ex.fe_logical - pa->pa_lstart);
3282 end = min(pa->pa_pstart + EXT4_C2B(sbi, pa->pa_len),
3283 start + EXT4_C2B(sbi, ac->ac_o_ex.fe_len));
3284 len = EXT4_NUM_B2C(sbi, end - start);
3285 ext4_get_group_no_and_offset(ac->ac_sb, start, &ac->ac_b_ex.fe_group,
3286 &ac->ac_b_ex.fe_start);
3287 ac->ac_b_ex.fe_len = len;
3288 ac->ac_status = AC_STATUS_FOUND;
3289 ac->ac_pa = pa;
3290
3291 BUG_ON(start < pa->pa_pstart);
3292 BUG_ON(end > pa->pa_pstart + EXT4_C2B(sbi, pa->pa_len));
3293 BUG_ON(pa->pa_free < len);
3294 pa->pa_free -= len;
3295
3296 mb_debug(1, "use %llu/%u from inode pa %p\n", start, len, pa);
3297 }
3298
3299 /*
3300 * use blocks preallocated to locality group
3301 */
ext4_mb_use_group_pa(struct ext4_allocation_context * ac,struct ext4_prealloc_space * pa)3302 static void ext4_mb_use_group_pa(struct ext4_allocation_context *ac,
3303 struct ext4_prealloc_space *pa)
3304 {
3305 unsigned int len = ac->ac_o_ex.fe_len;
3306
3307 ext4_get_group_no_and_offset(ac->ac_sb, pa->pa_pstart,
3308 &ac->ac_b_ex.fe_group,
3309 &ac->ac_b_ex.fe_start);
3310 ac->ac_b_ex.fe_len = len;
3311 ac->ac_status = AC_STATUS_FOUND;
3312 ac->ac_pa = pa;
3313
3314 /* we don't correct pa_pstart or pa_plen here to avoid
3315 * possible race when the group is being loaded concurrently
3316 * instead we correct pa later, after blocks are marked
3317 * in on-disk bitmap -- see ext4_mb_release_context()
3318 * Other CPUs are prevented from allocating from this pa by lg_mutex
3319 */
3320 mb_debug(1, "use %u/%u from group pa %p\n", pa->pa_lstart-len, len, pa);
3321 }
3322
3323 /*
3324 * Return the prealloc space that have minimal distance
3325 * from the goal block. @cpa is the prealloc
3326 * space that is having currently known minimal distance
3327 * from the goal block.
3328 */
3329 static struct ext4_prealloc_space *
ext4_mb_check_group_pa(ext4_fsblk_t goal_block,struct ext4_prealloc_space * pa,struct ext4_prealloc_space * cpa)3330 ext4_mb_check_group_pa(ext4_fsblk_t goal_block,
3331 struct ext4_prealloc_space *pa,
3332 struct ext4_prealloc_space *cpa)
3333 {
3334 ext4_fsblk_t cur_distance, new_distance;
3335
3336 if (cpa == NULL) {
3337 atomic_inc(&pa->pa_count);
3338 return pa;
3339 }
3340 cur_distance = abs(goal_block - cpa->pa_pstart);
3341 new_distance = abs(goal_block - pa->pa_pstart);
3342
3343 if (cur_distance <= new_distance)
3344 return cpa;
3345
3346 /* drop the previous reference */
3347 atomic_dec(&cpa->pa_count);
3348 atomic_inc(&pa->pa_count);
3349 return pa;
3350 }
3351
3352 /*
3353 * search goal blocks in preallocated space
3354 */
3355 static noinline_for_stack int
ext4_mb_use_preallocated(struct ext4_allocation_context * ac)3356 ext4_mb_use_preallocated(struct ext4_allocation_context *ac)
3357 {
3358 struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
3359 int order, i;
3360 struct ext4_inode_info *ei = EXT4_I(ac->ac_inode);
3361 struct ext4_locality_group *lg;
3362 struct ext4_prealloc_space *pa, *cpa = NULL;
3363 ext4_fsblk_t goal_block;
3364
3365 /* only data can be preallocated */
3366 if (!(ac->ac_flags & EXT4_MB_HINT_DATA))
3367 return 0;
3368
3369 /* first, try per-file preallocation */
3370 rcu_read_lock();
3371 list_for_each_entry_rcu(pa, &ei->i_prealloc_list, pa_inode_list) {
3372
3373 /* all fields in this condition don't change,
3374 * so we can skip locking for them */
3375 if (ac->ac_o_ex.fe_logical < pa->pa_lstart ||
3376 ac->ac_o_ex.fe_logical >= (pa->pa_lstart +
3377 EXT4_C2B(sbi, pa->pa_len)))
3378 continue;
3379
3380 /* non-extent files can't have physical blocks past 2^32 */
3381 if (!(ext4_test_inode_flag(ac->ac_inode, EXT4_INODE_EXTENTS)) &&
3382 (pa->pa_pstart + EXT4_C2B(sbi, pa->pa_len) >
3383 EXT4_MAX_BLOCK_FILE_PHYS))
3384 continue;
3385
3386 /* found preallocated blocks, use them */
3387 spin_lock(&pa->pa_lock);
3388 if (pa->pa_deleted == 0 && pa->pa_free) {
3389 atomic_inc(&pa->pa_count);
3390 ext4_mb_use_inode_pa(ac, pa);
3391 spin_unlock(&pa->pa_lock);
3392 ac->ac_criteria = 10;
3393 rcu_read_unlock();
3394 return 1;
3395 }
3396 spin_unlock(&pa->pa_lock);
3397 }
3398 rcu_read_unlock();
3399
3400 /* can we use group allocation? */
3401 if (!(ac->ac_flags & EXT4_MB_HINT_GROUP_ALLOC))
3402 return 0;
3403
3404 /* inode may have no locality group for some reason */
3405 lg = ac->ac_lg;
3406 if (lg == NULL)
3407 return 0;
3408 order = fls(ac->ac_o_ex.fe_len) - 1;
3409 if (order > PREALLOC_TB_SIZE - 1)
3410 /* The max size of hash table is PREALLOC_TB_SIZE */
3411 order = PREALLOC_TB_SIZE - 1;
3412
3413 goal_block = ext4_grp_offs_to_block(ac->ac_sb, &ac->ac_g_ex);
3414 /*
3415 * search for the prealloc space that is having
3416 * minimal distance from the goal block.
3417 */
3418 for (i = order; i < PREALLOC_TB_SIZE; i++) {
3419 rcu_read_lock();
3420 list_for_each_entry_rcu(pa, &lg->lg_prealloc_list[i],
3421 pa_inode_list) {
3422 spin_lock(&pa->pa_lock);
3423 if (pa->pa_deleted == 0 &&
3424 pa->pa_free >= ac->ac_o_ex.fe_len) {
3425
3426 cpa = ext4_mb_check_group_pa(goal_block,
3427 pa, cpa);
3428 }
3429 spin_unlock(&pa->pa_lock);
3430 }
3431 rcu_read_unlock();
3432 }
3433 if (cpa) {
3434 ext4_mb_use_group_pa(ac, cpa);
3435 ac->ac_criteria = 20;
3436 return 1;
3437 }
3438 return 0;
3439 }
3440
3441 /*
3442 * the function goes through all block freed in the group
3443 * but not yet committed and marks them used in in-core bitmap.
3444 * buddy must be generated from this bitmap
3445 * Need to be called with the ext4 group lock held
3446 */
ext4_mb_generate_from_freelist(struct super_block * sb,void * bitmap,ext4_group_t group)3447 static void ext4_mb_generate_from_freelist(struct super_block *sb, void *bitmap,
3448 ext4_group_t group)
3449 {
3450 struct rb_node *n;
3451 struct ext4_group_info *grp;
3452 struct ext4_free_data *entry;
3453
3454 grp = ext4_get_group_info(sb, group);
3455 n = rb_first(&(grp->bb_free_root));
3456
3457 while (n) {
3458 entry = rb_entry(n, struct ext4_free_data, efd_node);
3459 ext4_set_bits(bitmap, entry->efd_start_cluster, entry->efd_count);
3460 n = rb_next(n);
3461 }
3462 return;
3463 }
3464
3465 /*
3466 * the function goes through all preallocation in this group and marks them
3467 * used in in-core bitmap. buddy must be generated from this bitmap
3468 * Need to be called with ext4 group lock held
3469 */
3470 static noinline_for_stack
ext4_mb_generate_from_pa(struct super_block * sb,void * bitmap,ext4_group_t group)3471 void ext4_mb_generate_from_pa(struct super_block *sb, void *bitmap,
3472 ext4_group_t group)
3473 {
3474 struct ext4_group_info *grp = ext4_get_group_info(sb, group);
3475 struct ext4_prealloc_space *pa;
3476 struct list_head *cur;
3477 ext4_group_t groupnr;
3478 ext4_grpblk_t start;
3479 int preallocated = 0;
3480 int len;
3481
3482 /* all form of preallocation discards first load group,
3483 * so the only competing code is preallocation use.
3484 * we don't need any locking here
3485 * notice we do NOT ignore preallocations with pa_deleted
3486 * otherwise we could leave used blocks available for
3487 * allocation in buddy when concurrent ext4_mb_put_pa()
3488 * is dropping preallocation
3489 */
3490 list_for_each(cur, &grp->bb_prealloc_list) {
3491 pa = list_entry(cur, struct ext4_prealloc_space, pa_group_list);
3492 spin_lock(&pa->pa_lock);
3493 ext4_get_group_no_and_offset(sb, pa->pa_pstart,
3494 &groupnr, &start);
3495 len = pa->pa_len;
3496 spin_unlock(&pa->pa_lock);
3497 if (unlikely(len == 0))
3498 continue;
3499 BUG_ON(groupnr != group);
3500 ext4_set_bits(bitmap, start, len);
3501 preallocated += len;
3502 }
3503 mb_debug(1, "prellocated %u for group %u\n", preallocated, group);
3504 }
3505
ext4_mb_pa_callback(struct rcu_head * head)3506 static void ext4_mb_pa_callback(struct rcu_head *head)
3507 {
3508 struct ext4_prealloc_space *pa;
3509 pa = container_of(head, struct ext4_prealloc_space, u.pa_rcu);
3510
3511 BUG_ON(atomic_read(&pa->pa_count));
3512 BUG_ON(pa->pa_deleted == 0);
3513 kmem_cache_free(ext4_pspace_cachep, pa);
3514 }
3515
3516 /*
3517 * drops a reference to preallocated space descriptor
3518 * if this was the last reference and the space is consumed
3519 */
ext4_mb_put_pa(struct ext4_allocation_context * ac,struct super_block * sb,struct ext4_prealloc_space * pa)3520 static void ext4_mb_put_pa(struct ext4_allocation_context *ac,
3521 struct super_block *sb, struct ext4_prealloc_space *pa)
3522 {
3523 ext4_group_t grp;
3524 ext4_fsblk_t grp_blk;
3525
3526 /* in this short window concurrent discard can set pa_deleted */
3527 spin_lock(&pa->pa_lock);
3528 if (!atomic_dec_and_test(&pa->pa_count) || pa->pa_free != 0) {
3529 spin_unlock(&pa->pa_lock);
3530 return;
3531 }
3532
3533 if (pa->pa_deleted == 1) {
3534 spin_unlock(&pa->pa_lock);
3535 return;
3536 }
3537
3538 pa->pa_deleted = 1;
3539 spin_unlock(&pa->pa_lock);
3540
3541 grp_blk = pa->pa_pstart;
3542 /*
3543 * If doing group-based preallocation, pa_pstart may be in the
3544 * next group when pa is used up
3545 */
3546 if (pa->pa_type == MB_GROUP_PA)
3547 grp_blk--;
3548
3549 grp = ext4_get_group_number(sb, grp_blk);
3550
3551 /*
3552 * possible race:
3553 *
3554 * P1 (buddy init) P2 (regular allocation)
3555 * find block B in PA
3556 * copy on-disk bitmap to buddy
3557 * mark B in on-disk bitmap
3558 * drop PA from group
3559 * mark all PAs in buddy
3560 *
3561 * thus, P1 initializes buddy with B available. to prevent this
3562 * we make "copy" and "mark all PAs" atomic and serialize "drop PA"
3563 * against that pair
3564 */
3565 ext4_lock_group(sb, grp);
3566 list_del(&pa->pa_group_list);
3567 ext4_unlock_group(sb, grp);
3568
3569 spin_lock(pa->pa_obj_lock);
3570 list_del_rcu(&pa->pa_inode_list);
3571 spin_unlock(pa->pa_obj_lock);
3572
3573 call_rcu(&(pa)->u.pa_rcu, ext4_mb_pa_callback);
3574 }
3575
3576 /*
3577 * creates new preallocated space for given inode
3578 */
3579 static noinline_for_stack int
ext4_mb_new_inode_pa(struct ext4_allocation_context * ac)3580 ext4_mb_new_inode_pa(struct ext4_allocation_context *ac)
3581 {
3582 struct super_block *sb = ac->ac_sb;
3583 struct ext4_sb_info *sbi = EXT4_SB(sb);
3584 struct ext4_prealloc_space *pa;
3585 struct ext4_group_info *grp;
3586 struct ext4_inode_info *ei;
3587
3588 /* preallocate only when found space is larger then requested */
3589 BUG_ON(ac->ac_o_ex.fe_len >= ac->ac_b_ex.fe_len);
3590 BUG_ON(ac->ac_status != AC_STATUS_FOUND);
3591 BUG_ON(!S_ISREG(ac->ac_inode->i_mode));
3592
3593 pa = kmem_cache_alloc(ext4_pspace_cachep, GFP_NOFS);
3594 if (pa == NULL)
3595 return -ENOMEM;
3596
3597 if (ac->ac_b_ex.fe_len < ac->ac_g_ex.fe_len) {
3598 int winl;
3599 int wins;
3600 int win;
3601 int offs;
3602
3603 /* we can't allocate as much as normalizer wants.
3604 * so, found space must get proper lstart
3605 * to cover original request */
3606 BUG_ON(ac->ac_g_ex.fe_logical > ac->ac_o_ex.fe_logical);
3607 BUG_ON(ac->ac_g_ex.fe_len < ac->ac_o_ex.fe_len);
3608
3609 /* we're limited by original request in that
3610 * logical block must be covered any way
3611 * winl is window we can move our chunk within */
3612 winl = ac->ac_o_ex.fe_logical - ac->ac_g_ex.fe_logical;
3613
3614 /* also, we should cover whole original request */
3615 wins = EXT4_C2B(sbi, ac->ac_b_ex.fe_len - ac->ac_o_ex.fe_len);
3616
3617 /* the smallest one defines real window */
3618 win = min(winl, wins);
3619
3620 offs = ac->ac_o_ex.fe_logical %
3621 EXT4_C2B(sbi, ac->ac_b_ex.fe_len);
3622 if (offs && offs < win)
3623 win = offs;
3624
3625 ac->ac_b_ex.fe_logical = ac->ac_o_ex.fe_logical -
3626 EXT4_NUM_B2C(sbi, win);
3627 BUG_ON(ac->ac_o_ex.fe_logical < ac->ac_b_ex.fe_logical);
3628 BUG_ON(ac->ac_o_ex.fe_len > ac->ac_b_ex.fe_len);
3629 }
3630
3631 /* preallocation can change ac_b_ex, thus we store actually
3632 * allocated blocks for history */
3633 ac->ac_f_ex = ac->ac_b_ex;
3634
3635 pa->pa_lstart = ac->ac_b_ex.fe_logical;
3636 pa->pa_pstart = ext4_grp_offs_to_block(sb, &ac->ac_b_ex);
3637 pa->pa_len = ac->ac_b_ex.fe_len;
3638 pa->pa_free = pa->pa_len;
3639 atomic_set(&pa->pa_count, 1);
3640 spin_lock_init(&pa->pa_lock);
3641 INIT_LIST_HEAD(&pa->pa_inode_list);
3642 INIT_LIST_HEAD(&pa->pa_group_list);
3643 pa->pa_deleted = 0;
3644 pa->pa_type = MB_INODE_PA;
3645
3646 mb_debug(1, "new inode pa %p: %llu/%u for %u\n", pa,
3647 pa->pa_pstart, pa->pa_len, pa->pa_lstart);
3648 trace_ext4_mb_new_inode_pa(ac, pa);
3649
3650 ext4_mb_use_inode_pa(ac, pa);
3651 atomic_add(pa->pa_free, &sbi->s_mb_preallocated);
3652
3653 ei = EXT4_I(ac->ac_inode);
3654 grp = ext4_get_group_info(sb, ac->ac_b_ex.fe_group);
3655
3656 pa->pa_obj_lock = &ei->i_prealloc_lock;
3657 pa->pa_inode = ac->ac_inode;
3658
3659 ext4_lock_group(sb, ac->ac_b_ex.fe_group);
3660 list_add(&pa->pa_group_list, &grp->bb_prealloc_list);
3661 ext4_unlock_group(sb, ac->ac_b_ex.fe_group);
3662
3663 spin_lock(pa->pa_obj_lock);
3664 list_add_rcu(&pa->pa_inode_list, &ei->i_prealloc_list);
3665 spin_unlock(pa->pa_obj_lock);
3666
3667 return 0;
3668 }
3669
3670 /*
3671 * creates new preallocated space for locality group inodes belongs to
3672 */
3673 static noinline_for_stack int
ext4_mb_new_group_pa(struct ext4_allocation_context * ac)3674 ext4_mb_new_group_pa(struct ext4_allocation_context *ac)
3675 {
3676 struct super_block *sb = ac->ac_sb;
3677 struct ext4_locality_group *lg;
3678 struct ext4_prealloc_space *pa;
3679 struct ext4_group_info *grp;
3680
3681 /* preallocate only when found space is larger then requested */
3682 BUG_ON(ac->ac_o_ex.fe_len >= ac->ac_b_ex.fe_len);
3683 BUG_ON(ac->ac_status != AC_STATUS_FOUND);
3684 BUG_ON(!S_ISREG(ac->ac_inode->i_mode));
3685
3686 BUG_ON(ext4_pspace_cachep == NULL);
3687 pa = kmem_cache_alloc(ext4_pspace_cachep, GFP_NOFS);
3688 if (pa == NULL)
3689 return -ENOMEM;
3690
3691 /* preallocation can change ac_b_ex, thus we store actually
3692 * allocated blocks for history */
3693 ac->ac_f_ex = ac->ac_b_ex;
3694
3695 pa->pa_pstart = ext4_grp_offs_to_block(sb, &ac->ac_b_ex);
3696 pa->pa_lstart = pa->pa_pstart;
3697 pa->pa_len = ac->ac_b_ex.fe_len;
3698 pa->pa_free = pa->pa_len;
3699 atomic_set(&pa->pa_count, 1);
3700 spin_lock_init(&pa->pa_lock);
3701 INIT_LIST_HEAD(&pa->pa_inode_list);
3702 INIT_LIST_HEAD(&pa->pa_group_list);
3703 pa->pa_deleted = 0;
3704 pa->pa_type = MB_GROUP_PA;
3705
3706 mb_debug(1, "new group pa %p: %llu/%u for %u\n", pa,
3707 pa->pa_pstart, pa->pa_len, pa->pa_lstart);
3708 trace_ext4_mb_new_group_pa(ac, pa);
3709
3710 ext4_mb_use_group_pa(ac, pa);
3711 atomic_add(pa->pa_free, &EXT4_SB(sb)->s_mb_preallocated);
3712
3713 grp = ext4_get_group_info(sb, ac->ac_b_ex.fe_group);
3714 lg = ac->ac_lg;
3715 BUG_ON(lg == NULL);
3716
3717 pa->pa_obj_lock = &lg->lg_prealloc_lock;
3718 pa->pa_inode = NULL;
3719
3720 ext4_lock_group(sb, ac->ac_b_ex.fe_group);
3721 list_add(&pa->pa_group_list, &grp->bb_prealloc_list);
3722 ext4_unlock_group(sb, ac->ac_b_ex.fe_group);
3723
3724 /*
3725 * We will later add the new pa to the right bucket
3726 * after updating the pa_free in ext4_mb_release_context
3727 */
3728 return 0;
3729 }
3730
ext4_mb_new_preallocation(struct ext4_allocation_context * ac)3731 static int ext4_mb_new_preallocation(struct ext4_allocation_context *ac)
3732 {
3733 int err;
3734
3735 if (ac->ac_flags & EXT4_MB_HINT_GROUP_ALLOC)
3736 err = ext4_mb_new_group_pa(ac);
3737 else
3738 err = ext4_mb_new_inode_pa(ac);
3739 return err;
3740 }
3741
3742 /*
3743 * finds all unused blocks in on-disk bitmap, frees them in
3744 * in-core bitmap and buddy.
3745 * @pa must be unlinked from inode and group lists, so that
3746 * nobody else can find/use it.
3747 * the caller MUST hold group/inode locks.
3748 * TODO: optimize the case when there are no in-core structures yet
3749 */
3750 static noinline_for_stack int
ext4_mb_release_inode_pa(struct ext4_buddy * e4b,struct buffer_head * bitmap_bh,struct ext4_prealloc_space * pa)3751 ext4_mb_release_inode_pa(struct ext4_buddy *e4b, struct buffer_head *bitmap_bh,
3752 struct ext4_prealloc_space *pa)
3753 {
3754 struct super_block *sb = e4b->bd_sb;
3755 struct ext4_sb_info *sbi = EXT4_SB(sb);
3756 unsigned int end;
3757 unsigned int next;
3758 ext4_group_t group;
3759 ext4_grpblk_t bit;
3760 unsigned long long grp_blk_start;
3761 int err = 0;
3762 int free = 0;
3763
3764 BUG_ON(pa->pa_deleted == 0);
3765 ext4_get_group_no_and_offset(sb, pa->pa_pstart, &group, &bit);
3766 grp_blk_start = pa->pa_pstart - EXT4_C2B(sbi, bit);
3767 BUG_ON(group != e4b->bd_group && pa->pa_len != 0);
3768 end = bit + pa->pa_len;
3769
3770 while (bit < end) {
3771 bit = mb_find_next_zero_bit(bitmap_bh->b_data, end, bit);
3772 if (bit >= end)
3773 break;
3774 next = mb_find_next_bit(bitmap_bh->b_data, end, bit);
3775 mb_debug(1, " free preallocated %u/%u in group %u\n",
3776 (unsigned) ext4_group_first_block_no(sb, group) + bit,
3777 (unsigned) next - bit, (unsigned) group);
3778 free += next - bit;
3779
3780 trace_ext4_mballoc_discard(sb, NULL, group, bit, next - bit);
3781 trace_ext4_mb_release_inode_pa(pa, (grp_blk_start +
3782 EXT4_C2B(sbi, bit)),
3783 next - bit);
3784 mb_free_blocks(pa->pa_inode, e4b, bit, next - bit);
3785 bit = next + 1;
3786 }
3787 if (free != pa->pa_free) {
3788 ext4_msg(e4b->bd_sb, KERN_CRIT,
3789 "pa %p: logic %lu, phys. %lu, len %lu",
3790 pa, (unsigned long) pa->pa_lstart,
3791 (unsigned long) pa->pa_pstart,
3792 (unsigned long) pa->pa_len);
3793 ext4_grp_locked_error(sb, group, 0, 0, "free %u, pa_free %u",
3794 free, pa->pa_free);
3795 /*
3796 * pa is already deleted so we use the value obtained
3797 * from the bitmap and continue.
3798 */
3799 }
3800 atomic_add(free, &sbi->s_mb_discarded);
3801
3802 return err;
3803 }
3804
3805 static noinline_for_stack int
ext4_mb_release_group_pa(struct ext4_buddy * e4b,struct ext4_prealloc_space * pa)3806 ext4_mb_release_group_pa(struct ext4_buddy *e4b,
3807 struct ext4_prealloc_space *pa)
3808 {
3809 struct super_block *sb = e4b->bd_sb;
3810 ext4_group_t group;
3811 ext4_grpblk_t bit;
3812
3813 trace_ext4_mb_release_group_pa(sb, pa);
3814 BUG_ON(pa->pa_deleted == 0);
3815 ext4_get_group_no_and_offset(sb, pa->pa_pstart, &group, &bit);
3816 BUG_ON(group != e4b->bd_group && pa->pa_len != 0);
3817 mb_free_blocks(pa->pa_inode, e4b, bit, pa->pa_len);
3818 atomic_add(pa->pa_len, &EXT4_SB(sb)->s_mb_discarded);
3819 trace_ext4_mballoc_discard(sb, NULL, group, bit, pa->pa_len);
3820
3821 return 0;
3822 }
3823
3824 /*
3825 * releases all preallocations in given group
3826 *
3827 * first, we need to decide discard policy:
3828 * - when do we discard
3829 * 1) ENOSPC
3830 * - how many do we discard
3831 * 1) how many requested
3832 */
3833 static noinline_for_stack int
ext4_mb_discard_group_preallocations(struct super_block * sb,ext4_group_t group,int needed)3834 ext4_mb_discard_group_preallocations(struct super_block *sb,
3835 ext4_group_t group, int needed)
3836 {
3837 struct ext4_group_info *grp = ext4_get_group_info(sb, group);
3838 struct buffer_head *bitmap_bh = NULL;
3839 struct ext4_prealloc_space *pa, *tmp;
3840 struct list_head list;
3841 struct ext4_buddy e4b;
3842 int err;
3843 int busy = 0;
3844 int free = 0;
3845
3846 mb_debug(1, "discard preallocation for group %u\n", group);
3847
3848 if (list_empty(&grp->bb_prealloc_list))
3849 return 0;
3850
3851 bitmap_bh = ext4_read_block_bitmap(sb, group);
3852 if (IS_ERR(bitmap_bh)) {
3853 err = PTR_ERR(bitmap_bh);
3854 ext4_error(sb, "Error %d reading block bitmap for %u",
3855 err, group);
3856 return 0;
3857 }
3858
3859 err = ext4_mb_load_buddy(sb, group, &e4b);
3860 if (err) {
3861 ext4_error(sb, "Error loading buddy information for %u", group);
3862 put_bh(bitmap_bh);
3863 return 0;
3864 }
3865
3866 if (needed == 0)
3867 needed = EXT4_CLUSTERS_PER_GROUP(sb) + 1;
3868
3869 INIT_LIST_HEAD(&list);
3870 repeat:
3871 ext4_lock_group(sb, group);
3872 list_for_each_entry_safe(pa, tmp,
3873 &grp->bb_prealloc_list, pa_group_list) {
3874 spin_lock(&pa->pa_lock);
3875 if (atomic_read(&pa->pa_count)) {
3876 spin_unlock(&pa->pa_lock);
3877 busy = 1;
3878 continue;
3879 }
3880 if (pa->pa_deleted) {
3881 spin_unlock(&pa->pa_lock);
3882 continue;
3883 }
3884
3885 /* seems this one can be freed ... */
3886 pa->pa_deleted = 1;
3887
3888 /* we can trust pa_free ... */
3889 free += pa->pa_free;
3890
3891 spin_unlock(&pa->pa_lock);
3892
3893 list_del(&pa->pa_group_list);
3894 list_add(&pa->u.pa_tmp_list, &list);
3895 }
3896
3897 /* if we still need more blocks and some PAs were used, try again */
3898 if (free < needed && busy) {
3899 busy = 0;
3900 ext4_unlock_group(sb, group);
3901 cond_resched();
3902 goto repeat;
3903 }
3904
3905 /* found anything to free? */
3906 if (list_empty(&list)) {
3907 BUG_ON(free != 0);
3908 goto out;
3909 }
3910
3911 /* now free all selected PAs */
3912 list_for_each_entry_safe(pa, tmp, &list, u.pa_tmp_list) {
3913
3914 /* remove from object (inode or locality group) */
3915 spin_lock(pa->pa_obj_lock);
3916 list_del_rcu(&pa->pa_inode_list);
3917 spin_unlock(pa->pa_obj_lock);
3918
3919 if (pa->pa_type == MB_GROUP_PA)
3920 ext4_mb_release_group_pa(&e4b, pa);
3921 else
3922 ext4_mb_release_inode_pa(&e4b, bitmap_bh, pa);
3923
3924 list_del(&pa->u.pa_tmp_list);
3925 call_rcu(&(pa)->u.pa_rcu, ext4_mb_pa_callback);
3926 }
3927
3928 out:
3929 ext4_unlock_group(sb, group);
3930 ext4_mb_unload_buddy(&e4b);
3931 put_bh(bitmap_bh);
3932 return free;
3933 }
3934
3935 /*
3936 * releases all non-used preallocated blocks for given inode
3937 *
3938 * It's important to discard preallocations under i_data_sem
3939 * We don't want another block to be served from the prealloc
3940 * space when we are discarding the inode prealloc space.
3941 *
3942 * FIXME!! Make sure it is valid at all the call sites
3943 */
ext4_discard_preallocations(struct inode * inode)3944 void ext4_discard_preallocations(struct inode *inode)
3945 {
3946 struct ext4_inode_info *ei = EXT4_I(inode);
3947 struct super_block *sb = inode->i_sb;
3948 struct buffer_head *bitmap_bh = NULL;
3949 struct ext4_prealloc_space *pa, *tmp;
3950 ext4_group_t group = 0;
3951 struct list_head list;
3952 struct ext4_buddy e4b;
3953 int err;
3954
3955 if (!S_ISREG(inode->i_mode)) {
3956 /*BUG_ON(!list_empty(&ei->i_prealloc_list));*/
3957 return;
3958 }
3959
3960 mb_debug(1, "discard preallocation for inode %lu\n", inode->i_ino);
3961 trace_ext4_discard_preallocations(inode);
3962
3963 INIT_LIST_HEAD(&list);
3964
3965 repeat:
3966 /* first, collect all pa's in the inode */
3967 spin_lock(&ei->i_prealloc_lock);
3968 while (!list_empty(&ei->i_prealloc_list)) {
3969 pa = list_entry(ei->i_prealloc_list.next,
3970 struct ext4_prealloc_space, pa_inode_list);
3971 BUG_ON(pa->pa_obj_lock != &ei->i_prealloc_lock);
3972 spin_lock(&pa->pa_lock);
3973 if (atomic_read(&pa->pa_count)) {
3974 /* this shouldn't happen often - nobody should
3975 * use preallocation while we're discarding it */
3976 spin_unlock(&pa->pa_lock);
3977 spin_unlock(&ei->i_prealloc_lock);
3978 ext4_msg(sb, KERN_ERR,
3979 "uh-oh! used pa while discarding");
3980 WARN_ON(1);
3981 schedule_timeout_uninterruptible(HZ);
3982 goto repeat;
3983
3984 }
3985 if (pa->pa_deleted == 0) {
3986 pa->pa_deleted = 1;
3987 spin_unlock(&pa->pa_lock);
3988 list_del_rcu(&pa->pa_inode_list);
3989 list_add(&pa->u.pa_tmp_list, &list);
3990 continue;
3991 }
3992
3993 /* someone is deleting pa right now */
3994 spin_unlock(&pa->pa_lock);
3995 spin_unlock(&ei->i_prealloc_lock);
3996
3997 /* we have to wait here because pa_deleted
3998 * doesn't mean pa is already unlinked from
3999 * the list. as we might be called from
4000 * ->clear_inode() the inode will get freed
4001 * and concurrent thread which is unlinking
4002 * pa from inode's list may access already
4003 * freed memory, bad-bad-bad */
4004
4005 /* XXX: if this happens too often, we can
4006 * add a flag to force wait only in case
4007 * of ->clear_inode(), but not in case of
4008 * regular truncate */
4009 schedule_timeout_uninterruptible(HZ);
4010 goto repeat;
4011 }
4012 spin_unlock(&ei->i_prealloc_lock);
4013
4014 list_for_each_entry_safe(pa, tmp, &list, u.pa_tmp_list) {
4015 BUG_ON(pa->pa_type != MB_INODE_PA);
4016 group = ext4_get_group_number(sb, pa->pa_pstart);
4017
4018 err = ext4_mb_load_buddy(sb, group, &e4b);
4019 if (err) {
4020 ext4_error(sb, "Error loading buddy information for %u",
4021 group);
4022 continue;
4023 }
4024
4025 bitmap_bh = ext4_read_block_bitmap(sb, group);
4026 if (IS_ERR(bitmap_bh)) {
4027 err = PTR_ERR(bitmap_bh);
4028 ext4_error(sb, "Error %d reading block bitmap for %u",
4029 err, group);
4030 ext4_mb_unload_buddy(&e4b);
4031 continue;
4032 }
4033
4034 ext4_lock_group(sb, group);
4035 list_del(&pa->pa_group_list);
4036 ext4_mb_release_inode_pa(&e4b, bitmap_bh, pa);
4037 ext4_unlock_group(sb, group);
4038
4039 ext4_mb_unload_buddy(&e4b);
4040 put_bh(bitmap_bh);
4041
4042 list_del(&pa->u.pa_tmp_list);
4043 call_rcu(&(pa)->u.pa_rcu, ext4_mb_pa_callback);
4044 }
4045 }
4046
4047 #ifdef CONFIG_EXT4_DEBUG
ext4_mb_show_ac(struct ext4_allocation_context * ac)4048 static void ext4_mb_show_ac(struct ext4_allocation_context *ac)
4049 {
4050 struct super_block *sb = ac->ac_sb;
4051 ext4_group_t ngroups, i;
4052
4053 if (!ext4_mballoc_debug ||
4054 (EXT4_SB(sb)->s_mount_flags & EXT4_MF_FS_ABORTED))
4055 return;
4056
4057 ext4_msg(ac->ac_sb, KERN_ERR, "Can't allocate:"
4058 " Allocation context details:");
4059 ext4_msg(ac->ac_sb, KERN_ERR, "status %d flags %d",
4060 ac->ac_status, ac->ac_flags);
4061 ext4_msg(ac->ac_sb, KERN_ERR, "orig %lu/%lu/%lu@%lu, "
4062 "goal %lu/%lu/%lu@%lu, "
4063 "best %lu/%lu/%lu@%lu cr %d",
4064 (unsigned long)ac->ac_o_ex.fe_group,
4065 (unsigned long)ac->ac_o_ex.fe_start,
4066 (unsigned long)ac->ac_o_ex.fe_len,
4067 (unsigned long)ac->ac_o_ex.fe_logical,
4068 (unsigned long)ac->ac_g_ex.fe_group,
4069 (unsigned long)ac->ac_g_ex.fe_start,
4070 (unsigned long)ac->ac_g_ex.fe_len,
4071 (unsigned long)ac->ac_g_ex.fe_logical,
4072 (unsigned long)ac->ac_b_ex.fe_group,
4073 (unsigned long)ac->ac_b_ex.fe_start,
4074 (unsigned long)ac->ac_b_ex.fe_len,
4075 (unsigned long)ac->ac_b_ex.fe_logical,
4076 (int)ac->ac_criteria);
4077 ext4_msg(ac->ac_sb, KERN_ERR, "%d found", ac->ac_found);
4078 ext4_msg(ac->ac_sb, KERN_ERR, "groups: ");
4079 ngroups = ext4_get_groups_count(sb);
4080 for (i = 0; i < ngroups; i++) {
4081 struct ext4_group_info *grp = ext4_get_group_info(sb, i);
4082 struct ext4_prealloc_space *pa;
4083 ext4_grpblk_t start;
4084 struct list_head *cur;
4085 ext4_lock_group(sb, i);
4086 list_for_each(cur, &grp->bb_prealloc_list) {
4087 pa = list_entry(cur, struct ext4_prealloc_space,
4088 pa_group_list);
4089 spin_lock(&pa->pa_lock);
4090 ext4_get_group_no_and_offset(sb, pa->pa_pstart,
4091 NULL, &start);
4092 spin_unlock(&pa->pa_lock);
4093 printk(KERN_ERR "PA:%u:%d:%u \n", i,
4094 start, pa->pa_len);
4095 }
4096 ext4_unlock_group(sb, i);
4097
4098 if (grp->bb_free == 0)
4099 continue;
4100 printk(KERN_ERR "%u: %d/%d \n",
4101 i, grp->bb_free, grp->bb_fragments);
4102 }
4103 printk(KERN_ERR "\n");
4104 }
4105 #else
ext4_mb_show_ac(struct ext4_allocation_context * ac)4106 static inline void ext4_mb_show_ac(struct ext4_allocation_context *ac)
4107 {
4108 return;
4109 }
4110 #endif
4111
4112 /*
4113 * We use locality group preallocation for small size file. The size of the
4114 * file is determined by the current size or the resulting size after
4115 * allocation which ever is larger
4116 *
4117 * One can tune this size via /sys/fs/ext4/<partition>/mb_stream_req
4118 */
ext4_mb_group_or_file(struct ext4_allocation_context * ac)4119 static void ext4_mb_group_or_file(struct ext4_allocation_context *ac)
4120 {
4121 struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
4122 int bsbits = ac->ac_sb->s_blocksize_bits;
4123 loff_t size, isize;
4124
4125 if (!(ac->ac_flags & EXT4_MB_HINT_DATA))
4126 return;
4127
4128 if (unlikely(ac->ac_flags & EXT4_MB_HINT_GOAL_ONLY))
4129 return;
4130
4131 size = ac->ac_o_ex.fe_logical + EXT4_C2B(sbi, ac->ac_o_ex.fe_len);
4132 isize = (i_size_read(ac->ac_inode) + ac->ac_sb->s_blocksize - 1)
4133 >> bsbits;
4134
4135 if ((size == isize) &&
4136 !ext4_fs_is_busy(sbi) &&
4137 (atomic_read(&ac->ac_inode->i_writecount) == 0)) {
4138 ac->ac_flags |= EXT4_MB_HINT_NOPREALLOC;
4139 return;
4140 }
4141
4142 if (sbi->s_mb_group_prealloc <= 0) {
4143 ac->ac_flags |= EXT4_MB_STREAM_ALLOC;
4144 return;
4145 }
4146
4147 /* don't use group allocation for large files */
4148 size = max(size, isize);
4149 if (size > sbi->s_mb_stream_request) {
4150 ac->ac_flags |= EXT4_MB_STREAM_ALLOC;
4151 return;
4152 }
4153
4154 BUG_ON(ac->ac_lg != NULL);
4155 /*
4156 * locality group prealloc space are per cpu. The reason for having
4157 * per cpu locality group is to reduce the contention between block
4158 * request from multiple CPUs.
4159 */
4160 ac->ac_lg = raw_cpu_ptr(sbi->s_locality_groups);
4161
4162 /* we're going to use group allocation */
4163 ac->ac_flags |= EXT4_MB_HINT_GROUP_ALLOC;
4164
4165 /* serialize all allocations in the group */
4166 mutex_lock(&ac->ac_lg->lg_mutex);
4167 }
4168
4169 static noinline_for_stack int
ext4_mb_initialize_context(struct ext4_allocation_context * ac,struct ext4_allocation_request * ar)4170 ext4_mb_initialize_context(struct ext4_allocation_context *ac,
4171 struct ext4_allocation_request *ar)
4172 {
4173 struct super_block *sb = ar->inode->i_sb;
4174 struct ext4_sb_info *sbi = EXT4_SB(sb);
4175 struct ext4_super_block *es = sbi->s_es;
4176 ext4_group_t group;
4177 unsigned int len;
4178 ext4_fsblk_t goal;
4179 ext4_grpblk_t block;
4180
4181 /* we can't allocate > group size */
4182 len = ar->len;
4183
4184 /* just a dirty hack to filter too big requests */
4185 if (len >= EXT4_CLUSTERS_PER_GROUP(sb))
4186 len = EXT4_CLUSTERS_PER_GROUP(sb);
4187
4188 /* start searching from the goal */
4189 goal = ar->goal;
4190 if (goal < le32_to_cpu(es->s_first_data_block) ||
4191 goal >= ext4_blocks_count(es))
4192 goal = le32_to_cpu(es->s_first_data_block);
4193 ext4_get_group_no_and_offset(sb, goal, &group, &block);
4194
4195 /* set up allocation goals */
4196 ac->ac_b_ex.fe_logical = EXT4_LBLK_CMASK(sbi, ar->logical);
4197 ac->ac_status = AC_STATUS_CONTINUE;
4198 ac->ac_sb = sb;
4199 ac->ac_inode = ar->inode;
4200 ac->ac_o_ex.fe_logical = ac->ac_b_ex.fe_logical;
4201 ac->ac_o_ex.fe_group = group;
4202 ac->ac_o_ex.fe_start = block;
4203 ac->ac_o_ex.fe_len = len;
4204 ac->ac_g_ex = ac->ac_o_ex;
4205 ac->ac_flags = ar->flags;
4206
4207 /* we have to define context: we'll we work with a file or
4208 * locality group. this is a policy, actually */
4209 ext4_mb_group_or_file(ac);
4210
4211 mb_debug(1, "init ac: %u blocks @ %u, goal %u, flags %x, 2^%d, "
4212 "left: %u/%u, right %u/%u to %swritable\n",
4213 (unsigned) ar->len, (unsigned) ar->logical,
4214 (unsigned) ar->goal, ac->ac_flags, ac->ac_2order,
4215 (unsigned) ar->lleft, (unsigned) ar->pleft,
4216 (unsigned) ar->lright, (unsigned) ar->pright,
4217 atomic_read(&ar->inode->i_writecount) ? "" : "non-");
4218 return 0;
4219
4220 }
4221
4222 static noinline_for_stack void
ext4_mb_discard_lg_preallocations(struct super_block * sb,struct ext4_locality_group * lg,int order,int total_entries)4223 ext4_mb_discard_lg_preallocations(struct super_block *sb,
4224 struct ext4_locality_group *lg,
4225 int order, int total_entries)
4226 {
4227 ext4_group_t group = 0;
4228 struct ext4_buddy e4b;
4229 struct list_head discard_list;
4230 struct ext4_prealloc_space *pa, *tmp;
4231
4232 mb_debug(1, "discard locality group preallocation\n");
4233
4234 INIT_LIST_HEAD(&discard_list);
4235
4236 spin_lock(&lg->lg_prealloc_lock);
4237 list_for_each_entry_rcu(pa, &lg->lg_prealloc_list[order],
4238 pa_inode_list) {
4239 spin_lock(&pa->pa_lock);
4240 if (atomic_read(&pa->pa_count)) {
4241 /*
4242 * This is the pa that we just used
4243 * for block allocation. So don't
4244 * free that
4245 */
4246 spin_unlock(&pa->pa_lock);
4247 continue;
4248 }
4249 if (pa->pa_deleted) {
4250 spin_unlock(&pa->pa_lock);
4251 continue;
4252 }
4253 /* only lg prealloc space */
4254 BUG_ON(pa->pa_type != MB_GROUP_PA);
4255
4256 /* seems this one can be freed ... */
4257 pa->pa_deleted = 1;
4258 spin_unlock(&pa->pa_lock);
4259
4260 list_del_rcu(&pa->pa_inode_list);
4261 list_add(&pa->u.pa_tmp_list, &discard_list);
4262
4263 total_entries--;
4264 if (total_entries <= 5) {
4265 /*
4266 * we want to keep only 5 entries
4267 * allowing it to grow to 8. This
4268 * mak sure we don't call discard
4269 * soon for this list.
4270 */
4271 break;
4272 }
4273 }
4274 spin_unlock(&lg->lg_prealloc_lock);
4275
4276 list_for_each_entry_safe(pa, tmp, &discard_list, u.pa_tmp_list) {
4277
4278 group = ext4_get_group_number(sb, pa->pa_pstart);
4279 if (ext4_mb_load_buddy(sb, group, &e4b)) {
4280 ext4_error(sb, "Error loading buddy information for %u",
4281 group);
4282 continue;
4283 }
4284 ext4_lock_group(sb, group);
4285 list_del(&pa->pa_group_list);
4286 ext4_mb_release_group_pa(&e4b, pa);
4287 ext4_unlock_group(sb, group);
4288
4289 ext4_mb_unload_buddy(&e4b);
4290 list_del(&pa->u.pa_tmp_list);
4291 call_rcu(&(pa)->u.pa_rcu, ext4_mb_pa_callback);
4292 }
4293 }
4294
4295 /*
4296 * We have incremented pa_count. So it cannot be freed at this
4297 * point. Also we hold lg_mutex. So no parallel allocation is
4298 * possible from this lg. That means pa_free cannot be updated.
4299 *
4300 * A parallel ext4_mb_discard_group_preallocations is possible.
4301 * which can cause the lg_prealloc_list to be updated.
4302 */
4303
ext4_mb_add_n_trim(struct ext4_allocation_context * ac)4304 static void ext4_mb_add_n_trim(struct ext4_allocation_context *ac)
4305 {
4306 int order, added = 0, lg_prealloc_count = 1;
4307 struct super_block *sb = ac->ac_sb;
4308 struct ext4_locality_group *lg = ac->ac_lg;
4309 struct ext4_prealloc_space *tmp_pa, *pa = ac->ac_pa;
4310
4311 order = fls(pa->pa_free) - 1;
4312 if (order > PREALLOC_TB_SIZE - 1)
4313 /* The max size of hash table is PREALLOC_TB_SIZE */
4314 order = PREALLOC_TB_SIZE - 1;
4315 /* Add the prealloc space to lg */
4316 spin_lock(&lg->lg_prealloc_lock);
4317 list_for_each_entry_rcu(tmp_pa, &lg->lg_prealloc_list[order],
4318 pa_inode_list) {
4319 spin_lock(&tmp_pa->pa_lock);
4320 if (tmp_pa->pa_deleted) {
4321 spin_unlock(&tmp_pa->pa_lock);
4322 continue;
4323 }
4324 if (!added && pa->pa_free < tmp_pa->pa_free) {
4325 /* Add to the tail of the previous entry */
4326 list_add_tail_rcu(&pa->pa_inode_list,
4327 &tmp_pa->pa_inode_list);
4328 added = 1;
4329 /*
4330 * we want to count the total
4331 * number of entries in the list
4332 */
4333 }
4334 spin_unlock(&tmp_pa->pa_lock);
4335 lg_prealloc_count++;
4336 }
4337 if (!added)
4338 list_add_tail_rcu(&pa->pa_inode_list,
4339 &lg->lg_prealloc_list[order]);
4340 spin_unlock(&lg->lg_prealloc_lock);
4341
4342 /* Now trim the list to be not more than 8 elements */
4343 if (lg_prealloc_count > 8) {
4344 ext4_mb_discard_lg_preallocations(sb, lg,
4345 order, lg_prealloc_count);
4346 return;
4347 }
4348 return ;
4349 }
4350
4351 /*
4352 * release all resource we used in allocation
4353 */
ext4_mb_release_context(struct ext4_allocation_context * ac)4354 static int ext4_mb_release_context(struct ext4_allocation_context *ac)
4355 {
4356 struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
4357 struct ext4_prealloc_space *pa = ac->ac_pa;
4358 if (pa) {
4359 if (pa->pa_type == MB_GROUP_PA) {
4360 /* see comment in ext4_mb_use_group_pa() */
4361 spin_lock(&pa->pa_lock);
4362 pa->pa_pstart += EXT4_C2B(sbi, ac->ac_b_ex.fe_len);
4363 pa->pa_lstart += EXT4_C2B(sbi, ac->ac_b_ex.fe_len);
4364 pa->pa_free -= ac->ac_b_ex.fe_len;
4365 pa->pa_len -= ac->ac_b_ex.fe_len;
4366 spin_unlock(&pa->pa_lock);
4367 }
4368 }
4369 if (pa) {
4370 /*
4371 * We want to add the pa to the right bucket.
4372 * Remove it from the list and while adding
4373 * make sure the list to which we are adding
4374 * doesn't grow big.
4375 */
4376 if ((pa->pa_type == MB_GROUP_PA) && likely(pa->pa_free)) {
4377 spin_lock(pa->pa_obj_lock);
4378 list_del_rcu(&pa->pa_inode_list);
4379 spin_unlock(pa->pa_obj_lock);
4380 ext4_mb_add_n_trim(ac);
4381 }
4382 ext4_mb_put_pa(ac, ac->ac_sb, pa);
4383 }
4384 if (ac->ac_bitmap_page)
4385 page_cache_release(ac->ac_bitmap_page);
4386 if (ac->ac_buddy_page)
4387 page_cache_release(ac->ac_buddy_page);
4388 if (ac->ac_flags & EXT4_MB_HINT_GROUP_ALLOC)
4389 mutex_unlock(&ac->ac_lg->lg_mutex);
4390 ext4_mb_collect_stats(ac);
4391 return 0;
4392 }
4393
ext4_mb_discard_preallocations(struct super_block * sb,int needed)4394 static int ext4_mb_discard_preallocations(struct super_block *sb, int needed)
4395 {
4396 ext4_group_t i, ngroups = ext4_get_groups_count(sb);
4397 int ret;
4398 int freed = 0;
4399
4400 trace_ext4_mb_discard_preallocations(sb, needed);
4401 for (i = 0; i < ngroups && needed > 0; i++) {
4402 ret = ext4_mb_discard_group_preallocations(sb, i, needed);
4403 freed += ret;
4404 needed -= ret;
4405 }
4406
4407 return freed;
4408 }
4409
4410 /*
4411 * Main entry point into mballoc to allocate blocks
4412 * it tries to use preallocation first, then falls back
4413 * to usual allocation
4414 */
ext4_mb_new_blocks(handle_t * handle,struct ext4_allocation_request * ar,int * errp)4415 ext4_fsblk_t ext4_mb_new_blocks(handle_t *handle,
4416 struct ext4_allocation_request *ar, int *errp)
4417 {
4418 int freed;
4419 struct ext4_allocation_context *ac = NULL;
4420 struct ext4_sb_info *sbi;
4421 struct super_block *sb;
4422 ext4_fsblk_t block = 0;
4423 unsigned int inquota = 0;
4424 unsigned int reserv_clstrs = 0;
4425
4426 might_sleep();
4427 sb = ar->inode->i_sb;
4428 sbi = EXT4_SB(sb);
4429
4430 trace_ext4_request_blocks(ar);
4431
4432 /* Allow to use superuser reservation for quota file */
4433 if (IS_NOQUOTA(ar->inode))
4434 ar->flags |= EXT4_MB_USE_ROOT_BLOCKS;
4435
4436 if ((ar->flags & EXT4_MB_DELALLOC_RESERVED) == 0) {
4437 /* Without delayed allocation we need to verify
4438 * there is enough free blocks to do block allocation
4439 * and verify allocation doesn't exceed the quota limits.
4440 */
4441 while (ar->len &&
4442 ext4_claim_free_clusters(sbi, ar->len, ar->flags)) {
4443
4444 /* let others to free the space */
4445 cond_resched();
4446 ar->len = ar->len >> 1;
4447 }
4448 if (!ar->len) {
4449 *errp = -ENOSPC;
4450 return 0;
4451 }
4452 reserv_clstrs = ar->len;
4453 if (ar->flags & EXT4_MB_USE_ROOT_BLOCKS) {
4454 dquot_alloc_block_nofail(ar->inode,
4455 EXT4_C2B(sbi, ar->len));
4456 } else {
4457 while (ar->len &&
4458 dquot_alloc_block(ar->inode,
4459 EXT4_C2B(sbi, ar->len))) {
4460
4461 ar->flags |= EXT4_MB_HINT_NOPREALLOC;
4462 ar->len--;
4463 }
4464 }
4465 inquota = ar->len;
4466 if (ar->len == 0) {
4467 *errp = -EDQUOT;
4468 goto out;
4469 }
4470 }
4471
4472 ac = kmem_cache_zalloc(ext4_ac_cachep, GFP_NOFS);
4473 if (!ac) {
4474 ar->len = 0;
4475 *errp = -ENOMEM;
4476 goto out;
4477 }
4478
4479 *errp = ext4_mb_initialize_context(ac, ar);
4480 if (*errp) {
4481 ar->len = 0;
4482 goto out;
4483 }
4484
4485 ac->ac_op = EXT4_MB_HISTORY_PREALLOC;
4486 if (!ext4_mb_use_preallocated(ac)) {
4487 ac->ac_op = EXT4_MB_HISTORY_ALLOC;
4488 ext4_mb_normalize_request(ac, ar);
4489 repeat:
4490 /* allocate space in core */
4491 *errp = ext4_mb_regular_allocator(ac);
4492 if (*errp)
4493 goto discard_and_exit;
4494
4495 /* as we've just preallocated more space than
4496 * user requested originally, we store allocated
4497 * space in a special descriptor */
4498 if (ac->ac_status == AC_STATUS_FOUND &&
4499 ac->ac_o_ex.fe_len < ac->ac_b_ex.fe_len)
4500 *errp = ext4_mb_new_preallocation(ac);
4501 if (*errp) {
4502 discard_and_exit:
4503 ext4_discard_allocated_blocks(ac);
4504 goto errout;
4505 }
4506 }
4507 if (likely(ac->ac_status == AC_STATUS_FOUND)) {
4508 *errp = ext4_mb_mark_diskspace_used(ac, handle, reserv_clstrs);
4509 if (*errp == -EAGAIN) {
4510 /*
4511 * drop the reference that we took
4512 * in ext4_mb_use_best_found
4513 */
4514 ext4_mb_release_context(ac);
4515 ac->ac_b_ex.fe_group = 0;
4516 ac->ac_b_ex.fe_start = 0;
4517 ac->ac_b_ex.fe_len = 0;
4518 ac->ac_status = AC_STATUS_CONTINUE;
4519 goto repeat;
4520 } else if (*errp) {
4521 ext4_discard_allocated_blocks(ac);
4522 goto errout;
4523 } else {
4524 block = ext4_grp_offs_to_block(sb, &ac->ac_b_ex);
4525 ar->len = ac->ac_b_ex.fe_len;
4526 }
4527 } else {
4528 freed = ext4_mb_discard_preallocations(sb, ac->ac_o_ex.fe_len);
4529 if (freed)
4530 goto repeat;
4531 *errp = -ENOSPC;
4532 }
4533
4534 errout:
4535 if (*errp) {
4536 ac->ac_b_ex.fe_len = 0;
4537 ar->len = 0;
4538 ext4_mb_show_ac(ac);
4539 }
4540 ext4_mb_release_context(ac);
4541 out:
4542 if (ac)
4543 kmem_cache_free(ext4_ac_cachep, ac);
4544 if (inquota && ar->len < inquota)
4545 dquot_free_block(ar->inode, EXT4_C2B(sbi, inquota - ar->len));
4546 if (!ar->len) {
4547 if ((ar->flags & EXT4_MB_DELALLOC_RESERVED) == 0)
4548 /* release all the reserved blocks if non delalloc */
4549 percpu_counter_sub(&sbi->s_dirtyclusters_counter,
4550 reserv_clstrs);
4551 }
4552
4553 trace_ext4_allocate_blocks(ar, (unsigned long long)block);
4554
4555 return block;
4556 }
4557
4558 /*
4559 * We can merge two free data extents only if the physical blocks
4560 * are contiguous, AND the extents were freed by the same transaction,
4561 * AND the blocks are associated with the same group.
4562 */
can_merge(struct ext4_free_data * entry1,struct ext4_free_data * entry2)4563 static int can_merge(struct ext4_free_data *entry1,
4564 struct ext4_free_data *entry2)
4565 {
4566 if ((entry1->efd_tid == entry2->efd_tid) &&
4567 (entry1->efd_group == entry2->efd_group) &&
4568 ((entry1->efd_start_cluster + entry1->efd_count) == entry2->efd_start_cluster))
4569 return 1;
4570 return 0;
4571 }
4572
4573 static noinline_for_stack int
ext4_mb_free_metadata(handle_t * handle,struct ext4_buddy * e4b,struct ext4_free_data * new_entry)4574 ext4_mb_free_metadata(handle_t *handle, struct ext4_buddy *e4b,
4575 struct ext4_free_data *new_entry)
4576 {
4577 ext4_group_t group = e4b->bd_group;
4578 ext4_grpblk_t cluster;
4579 struct ext4_free_data *entry;
4580 struct ext4_group_info *db = e4b->bd_info;
4581 struct super_block *sb = e4b->bd_sb;
4582 struct ext4_sb_info *sbi = EXT4_SB(sb);
4583 struct rb_node **n = &db->bb_free_root.rb_node, *node;
4584 struct rb_node *parent = NULL, *new_node;
4585
4586 BUG_ON(!ext4_handle_valid(handle));
4587 BUG_ON(e4b->bd_bitmap_page == NULL);
4588 BUG_ON(e4b->bd_buddy_page == NULL);
4589
4590 new_node = &new_entry->efd_node;
4591 cluster = new_entry->efd_start_cluster;
4592
4593 if (!*n) {
4594 /* first free block exent. We need to
4595 protect buddy cache from being freed,
4596 * otherwise we'll refresh it from
4597 * on-disk bitmap and lose not-yet-available
4598 * blocks */
4599 page_cache_get(e4b->bd_buddy_page);
4600 page_cache_get(e4b->bd_bitmap_page);
4601 }
4602 while (*n) {
4603 parent = *n;
4604 entry = rb_entry(parent, struct ext4_free_data, efd_node);
4605 if (cluster < entry->efd_start_cluster)
4606 n = &(*n)->rb_left;
4607 else if (cluster >= (entry->efd_start_cluster + entry->efd_count))
4608 n = &(*n)->rb_right;
4609 else {
4610 ext4_grp_locked_error(sb, group, 0,
4611 ext4_group_first_block_no(sb, group) +
4612 EXT4_C2B(sbi, cluster),
4613 "Block already on to-be-freed list");
4614 return 0;
4615 }
4616 }
4617
4618 rb_link_node(new_node, parent, n);
4619 rb_insert_color(new_node, &db->bb_free_root);
4620
4621 /* Now try to see the extent can be merged to left and right */
4622 node = rb_prev(new_node);
4623 if (node) {
4624 entry = rb_entry(node, struct ext4_free_data, efd_node);
4625 if (can_merge(entry, new_entry) &&
4626 ext4_journal_callback_try_del(handle, &entry->efd_jce)) {
4627 new_entry->efd_start_cluster = entry->efd_start_cluster;
4628 new_entry->efd_count += entry->efd_count;
4629 rb_erase(node, &(db->bb_free_root));
4630 kmem_cache_free(ext4_free_data_cachep, entry);
4631 }
4632 }
4633
4634 node = rb_next(new_node);
4635 if (node) {
4636 entry = rb_entry(node, struct ext4_free_data, efd_node);
4637 if (can_merge(new_entry, entry) &&
4638 ext4_journal_callback_try_del(handle, &entry->efd_jce)) {
4639 new_entry->efd_count += entry->efd_count;
4640 rb_erase(node, &(db->bb_free_root));
4641 kmem_cache_free(ext4_free_data_cachep, entry);
4642 }
4643 }
4644 /* Add the extent to transaction's private list */
4645 ext4_journal_callback_add(handle, ext4_free_data_callback,
4646 &new_entry->efd_jce);
4647 return 0;
4648 }
4649
4650 /**
4651 * ext4_free_blocks() -- Free given blocks and update quota
4652 * @handle: handle for this transaction
4653 * @inode: inode
4654 * @block: start physical block to free
4655 * @count: number of blocks to count
4656 * @flags: flags used by ext4_free_blocks
4657 */
ext4_free_blocks(handle_t * handle,struct inode * inode,struct buffer_head * bh,ext4_fsblk_t block,unsigned long count,int flags)4658 void ext4_free_blocks(handle_t *handle, struct inode *inode,
4659 struct buffer_head *bh, ext4_fsblk_t block,
4660 unsigned long count, int flags)
4661 {
4662 struct buffer_head *bitmap_bh = NULL;
4663 struct super_block *sb = inode->i_sb;
4664 struct ext4_group_desc *gdp;
4665 unsigned int overflow;
4666 ext4_grpblk_t bit;
4667 struct buffer_head *gd_bh;
4668 ext4_group_t block_group;
4669 struct ext4_sb_info *sbi;
4670 struct ext4_buddy e4b;
4671 unsigned int count_clusters;
4672 int err = 0;
4673 int ret;
4674
4675 might_sleep();
4676 if (bh) {
4677 if (block)
4678 BUG_ON(block != bh->b_blocknr);
4679 else
4680 block = bh->b_blocknr;
4681 }
4682
4683 sbi = EXT4_SB(sb);
4684 if (!(flags & EXT4_FREE_BLOCKS_VALIDATED) &&
4685 !ext4_data_block_valid(sbi, block, count)) {
4686 ext4_error(sb, "Freeing blocks not in datazone - "
4687 "block = %llu, count = %lu", block, count);
4688 goto error_return;
4689 }
4690
4691 ext4_debug("freeing block %llu\n", block);
4692 trace_ext4_free_blocks(inode, block, count, flags);
4693
4694 if (bh && (flags & EXT4_FREE_BLOCKS_FORGET)) {
4695 BUG_ON(count > 1);
4696
4697 ext4_forget(handle, flags & EXT4_FREE_BLOCKS_METADATA,
4698 inode, bh, block);
4699 }
4700
4701 /*
4702 * We need to make sure we don't reuse the freed block until
4703 * after the transaction is committed, which we can do by
4704 * treating the block as metadata, below. We make an
4705 * exception if the inode is to be written in writeback mode
4706 * since writeback mode has weak data consistency guarantees.
4707 */
4708 if (!ext4_should_writeback_data(inode))
4709 flags |= EXT4_FREE_BLOCKS_METADATA;
4710
4711 /*
4712 * If the extent to be freed does not begin on a cluster
4713 * boundary, we need to deal with partial clusters at the
4714 * beginning and end of the extent. Normally we will free
4715 * blocks at the beginning or the end unless we are explicitly
4716 * requested to avoid doing so.
4717 */
4718 overflow = EXT4_PBLK_COFF(sbi, block);
4719 if (overflow) {
4720 if (flags & EXT4_FREE_BLOCKS_NOFREE_FIRST_CLUSTER) {
4721 overflow = sbi->s_cluster_ratio - overflow;
4722 block += overflow;
4723 if (count > overflow)
4724 count -= overflow;
4725 else
4726 return;
4727 } else {
4728 block -= overflow;
4729 count += overflow;
4730 }
4731 }
4732 overflow = EXT4_LBLK_COFF(sbi, count);
4733 if (overflow) {
4734 if (flags & EXT4_FREE_BLOCKS_NOFREE_LAST_CLUSTER) {
4735 if (count > overflow)
4736 count -= overflow;
4737 else
4738 return;
4739 } else
4740 count += sbi->s_cluster_ratio - overflow;
4741 }
4742
4743 if (!bh && (flags & EXT4_FREE_BLOCKS_FORGET)) {
4744 int i;
4745
4746 for (i = 0; i < count; i++) {
4747 cond_resched();
4748 bh = sb_find_get_block(inode->i_sb, block + i);
4749 if (!bh)
4750 continue;
4751 ext4_forget(handle, flags & EXT4_FREE_BLOCKS_METADATA,
4752 inode, bh, block + i);
4753 }
4754 }
4755
4756 do_more:
4757 overflow = 0;
4758 ext4_get_group_no_and_offset(sb, block, &block_group, &bit);
4759
4760 if (unlikely(EXT4_MB_GRP_BBITMAP_CORRUPT(
4761 ext4_get_group_info(sb, block_group))))
4762 return;
4763
4764 /*
4765 * Check to see if we are freeing blocks across a group
4766 * boundary.
4767 */
4768 if (EXT4_C2B(sbi, bit) + count > EXT4_BLOCKS_PER_GROUP(sb)) {
4769 overflow = EXT4_C2B(sbi, bit) + count -
4770 EXT4_BLOCKS_PER_GROUP(sb);
4771 count -= overflow;
4772 }
4773 count_clusters = EXT4_NUM_B2C(sbi, count);
4774 bitmap_bh = ext4_read_block_bitmap(sb, block_group);
4775 if (IS_ERR(bitmap_bh)) {
4776 err = PTR_ERR(bitmap_bh);
4777 bitmap_bh = NULL;
4778 goto error_return;
4779 }
4780 gdp = ext4_get_group_desc(sb, block_group, &gd_bh);
4781 if (!gdp) {
4782 err = -EIO;
4783 goto error_return;
4784 }
4785
4786 if (in_range(ext4_block_bitmap(sb, gdp), block, count) ||
4787 in_range(ext4_inode_bitmap(sb, gdp), block, count) ||
4788 in_range(block, ext4_inode_table(sb, gdp),
4789 EXT4_SB(sb)->s_itb_per_group) ||
4790 in_range(block + count - 1, ext4_inode_table(sb, gdp),
4791 EXT4_SB(sb)->s_itb_per_group)) {
4792
4793 ext4_error(sb, "Freeing blocks in system zone - "
4794 "Block = %llu, count = %lu", block, count);
4795 /* err = 0. ext4_std_error should be a no op */
4796 goto error_return;
4797 }
4798
4799 BUFFER_TRACE(bitmap_bh, "getting write access");
4800 err = ext4_journal_get_write_access(handle, bitmap_bh);
4801 if (err)
4802 goto error_return;
4803
4804 /*
4805 * We are about to modify some metadata. Call the journal APIs
4806 * to unshare ->b_data if a currently-committing transaction is
4807 * using it
4808 */
4809 BUFFER_TRACE(gd_bh, "get_write_access");
4810 err = ext4_journal_get_write_access(handle, gd_bh);
4811 if (err)
4812 goto error_return;
4813 #ifdef AGGRESSIVE_CHECK
4814 {
4815 int i;
4816 for (i = 0; i < count_clusters; i++)
4817 BUG_ON(!mb_test_bit(bit + i, bitmap_bh->b_data));
4818 }
4819 #endif
4820 trace_ext4_mballoc_free(sb, inode, block_group, bit, count_clusters);
4821
4822 err = ext4_mb_load_buddy(sb, block_group, &e4b);
4823 if (err)
4824 goto error_return;
4825
4826 if ((flags & EXT4_FREE_BLOCKS_METADATA) && ext4_handle_valid(handle)) {
4827 struct ext4_free_data *new_entry;
4828 /*
4829 * blocks being freed are metadata. these blocks shouldn't
4830 * be used until this transaction is committed
4831 *
4832 * We use __GFP_NOFAIL because ext4_free_blocks() is not allowed
4833 * to fail.
4834 */
4835 new_entry = kmem_cache_alloc(ext4_free_data_cachep,
4836 GFP_NOFS|__GFP_NOFAIL);
4837 new_entry->efd_start_cluster = bit;
4838 new_entry->efd_group = block_group;
4839 new_entry->efd_count = count_clusters;
4840 new_entry->efd_tid = handle->h_transaction->t_tid;
4841
4842 ext4_lock_group(sb, block_group);
4843 mb_clear_bits(bitmap_bh->b_data, bit, count_clusters);
4844 ext4_mb_free_metadata(handle, &e4b, new_entry);
4845 } else {
4846 /* need to update group_info->bb_free and bitmap
4847 * with group lock held. generate_buddy look at
4848 * them with group lock_held
4849 */
4850 if (test_opt(sb, DISCARD)) {
4851 err = ext4_issue_discard(sb, block_group, bit, count);
4852 if (err && err != -EOPNOTSUPP)
4853 ext4_msg(sb, KERN_WARNING, "discard request in"
4854 " group:%d block:%d count:%lu failed"
4855 " with %d", block_group, bit, count,
4856 err);
4857 } else
4858 EXT4_MB_GRP_CLEAR_TRIMMED(e4b.bd_info);
4859
4860 ext4_lock_group(sb, block_group);
4861 mb_clear_bits(bitmap_bh->b_data, bit, count_clusters);
4862 mb_free_blocks(inode, &e4b, bit, count_clusters);
4863 }
4864
4865 ret = ext4_free_group_clusters(sb, gdp) + count_clusters;
4866 ext4_free_group_clusters_set(sb, gdp, ret);
4867 ext4_block_bitmap_csum_set(sb, block_group, gdp, bitmap_bh);
4868 ext4_group_desc_csum_set(sb, block_group, gdp);
4869 ext4_unlock_group(sb, block_group);
4870
4871 if (sbi->s_log_groups_per_flex) {
4872 ext4_group_t flex_group = ext4_flex_group(sbi, block_group);
4873 atomic64_add(count_clusters,
4874 &sbi->s_flex_groups[flex_group].free_clusters);
4875 }
4876
4877 if (!(flags & EXT4_FREE_BLOCKS_NO_QUOT_UPDATE))
4878 dquot_free_block(inode, EXT4_C2B(sbi, count_clusters));
4879 percpu_counter_add(&sbi->s_freeclusters_counter, count_clusters);
4880
4881 ext4_mb_unload_buddy(&e4b);
4882
4883 /* We dirtied the bitmap block */
4884 BUFFER_TRACE(bitmap_bh, "dirtied bitmap block");
4885 err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
4886
4887 /* And the group descriptor block */
4888 BUFFER_TRACE(gd_bh, "dirtied group descriptor block");
4889 ret = ext4_handle_dirty_metadata(handle, NULL, gd_bh);
4890 if (!err)
4891 err = ret;
4892
4893 if (overflow && !err) {
4894 block += count;
4895 count = overflow;
4896 put_bh(bitmap_bh);
4897 goto do_more;
4898 }
4899 error_return:
4900 brelse(bitmap_bh);
4901 ext4_std_error(sb, err);
4902 return;
4903 }
4904
4905 /**
4906 * ext4_group_add_blocks() -- Add given blocks to an existing group
4907 * @handle: handle to this transaction
4908 * @sb: super block
4909 * @block: start physical block to add to the block group
4910 * @count: number of blocks to free
4911 *
4912 * This marks the blocks as free in the bitmap and buddy.
4913 */
ext4_group_add_blocks(handle_t * handle,struct super_block * sb,ext4_fsblk_t block,unsigned long count)4914 int ext4_group_add_blocks(handle_t *handle, struct super_block *sb,
4915 ext4_fsblk_t block, unsigned long count)
4916 {
4917 struct buffer_head *bitmap_bh = NULL;
4918 struct buffer_head *gd_bh;
4919 ext4_group_t block_group;
4920 ext4_grpblk_t bit;
4921 unsigned int i;
4922 struct ext4_group_desc *desc;
4923 struct ext4_sb_info *sbi = EXT4_SB(sb);
4924 struct ext4_buddy e4b;
4925 int err = 0, ret, blk_free_count;
4926 ext4_grpblk_t blocks_freed;
4927
4928 ext4_debug("Adding block(s) %llu-%llu\n", block, block + count - 1);
4929
4930 if (count == 0)
4931 return 0;
4932
4933 ext4_get_group_no_and_offset(sb, block, &block_group, &bit);
4934 /*
4935 * Check to see if we are freeing blocks across a group
4936 * boundary.
4937 */
4938 if (bit + count > EXT4_BLOCKS_PER_GROUP(sb)) {
4939 ext4_warning(sb, "too much blocks added to group %u\n",
4940 block_group);
4941 err = -EINVAL;
4942 goto error_return;
4943 }
4944
4945 bitmap_bh = ext4_read_block_bitmap(sb, block_group);
4946 if (IS_ERR(bitmap_bh)) {
4947 err = PTR_ERR(bitmap_bh);
4948 bitmap_bh = NULL;
4949 goto error_return;
4950 }
4951
4952 desc = ext4_get_group_desc(sb, block_group, &gd_bh);
4953 if (!desc) {
4954 err = -EIO;
4955 goto error_return;
4956 }
4957
4958 if (in_range(ext4_block_bitmap(sb, desc), block, count) ||
4959 in_range(ext4_inode_bitmap(sb, desc), block, count) ||
4960 in_range(block, ext4_inode_table(sb, desc), sbi->s_itb_per_group) ||
4961 in_range(block + count - 1, ext4_inode_table(sb, desc),
4962 sbi->s_itb_per_group)) {
4963 ext4_error(sb, "Adding blocks in system zones - "
4964 "Block = %llu, count = %lu",
4965 block, count);
4966 err = -EINVAL;
4967 goto error_return;
4968 }
4969
4970 BUFFER_TRACE(bitmap_bh, "getting write access");
4971 err = ext4_journal_get_write_access(handle, bitmap_bh);
4972 if (err)
4973 goto error_return;
4974
4975 /*
4976 * We are about to modify some metadata. Call the journal APIs
4977 * to unshare ->b_data if a currently-committing transaction is
4978 * using it
4979 */
4980 BUFFER_TRACE(gd_bh, "get_write_access");
4981 err = ext4_journal_get_write_access(handle, gd_bh);
4982 if (err)
4983 goto error_return;
4984
4985 for (i = 0, blocks_freed = 0; i < count; i++) {
4986 BUFFER_TRACE(bitmap_bh, "clear bit");
4987 if (!mb_test_bit(bit + i, bitmap_bh->b_data)) {
4988 ext4_error(sb, "bit already cleared for block %llu",
4989 (ext4_fsblk_t)(block + i));
4990 BUFFER_TRACE(bitmap_bh, "bit already cleared");
4991 } else {
4992 blocks_freed++;
4993 }
4994 }
4995
4996 err = ext4_mb_load_buddy(sb, block_group, &e4b);
4997 if (err)
4998 goto error_return;
4999
5000 /*
5001 * need to update group_info->bb_free and bitmap
5002 * with group lock held. generate_buddy look at
5003 * them with group lock_held
5004 */
5005 ext4_lock_group(sb, block_group);
5006 mb_clear_bits(bitmap_bh->b_data, bit, count);
5007 mb_free_blocks(NULL, &e4b, bit, count);
5008 blk_free_count = blocks_freed + ext4_free_group_clusters(sb, desc);
5009 ext4_free_group_clusters_set(sb, desc, blk_free_count);
5010 ext4_block_bitmap_csum_set(sb, block_group, desc, bitmap_bh);
5011 ext4_group_desc_csum_set(sb, block_group, desc);
5012 ext4_unlock_group(sb, block_group);
5013 percpu_counter_add(&sbi->s_freeclusters_counter,
5014 EXT4_NUM_B2C(sbi, blocks_freed));
5015
5016 if (sbi->s_log_groups_per_flex) {
5017 ext4_group_t flex_group = ext4_flex_group(sbi, block_group);
5018 atomic64_add(EXT4_NUM_B2C(sbi, blocks_freed),
5019 &sbi->s_flex_groups[flex_group].free_clusters);
5020 }
5021
5022 ext4_mb_unload_buddy(&e4b);
5023
5024 /* We dirtied the bitmap block */
5025 BUFFER_TRACE(bitmap_bh, "dirtied bitmap block");
5026 err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
5027
5028 /* And the group descriptor block */
5029 BUFFER_TRACE(gd_bh, "dirtied group descriptor block");
5030 ret = ext4_handle_dirty_metadata(handle, NULL, gd_bh);
5031 if (!err)
5032 err = ret;
5033
5034 error_return:
5035 brelse(bitmap_bh);
5036 ext4_std_error(sb, err);
5037 return err;
5038 }
5039
5040 /**
5041 * ext4_trim_extent -- function to TRIM one single free extent in the group
5042 * @sb: super block for the file system
5043 * @start: starting block of the free extent in the alloc. group
5044 * @count: number of blocks to TRIM
5045 * @group: alloc. group we are working with
5046 * @e4b: ext4 buddy for the group
5047 *
5048 * Trim "count" blocks starting at "start" in the "group". To assure that no
5049 * one will allocate those blocks, mark it as used in buddy bitmap. This must
5050 * be called with under the group lock.
5051 */
ext4_trim_extent(struct super_block * sb,int start,int count,ext4_group_t group,struct ext4_buddy * e4b)5052 static int ext4_trim_extent(struct super_block *sb, int start, int count,
5053 ext4_group_t group, struct ext4_buddy *e4b)
5054 __releases(bitlock)
5055 __acquires(bitlock)
5056 {
5057 struct ext4_free_extent ex;
5058 int ret = 0;
5059
5060 trace_ext4_trim_extent(sb, group, start, count);
5061
5062 assert_spin_locked(ext4_group_lock_ptr(sb, group));
5063
5064 ex.fe_start = start;
5065 ex.fe_group = group;
5066 ex.fe_len = count;
5067
5068 /*
5069 * Mark blocks used, so no one can reuse them while
5070 * being trimmed.
5071 */
5072 mb_mark_used(e4b, &ex);
5073 ext4_unlock_group(sb, group);
5074 ret = ext4_issue_discard(sb, group, start, count);
5075 ext4_lock_group(sb, group);
5076 mb_free_blocks(NULL, e4b, start, ex.fe_len);
5077 return ret;
5078 }
5079
5080 /**
5081 * ext4_trim_all_free -- function to trim all free space in alloc. group
5082 * @sb: super block for file system
5083 * @group: group to be trimmed
5084 * @start: first group block to examine
5085 * @max: last group block to examine
5086 * @minblocks: minimum extent block count
5087 *
5088 * ext4_trim_all_free walks through group's buddy bitmap searching for free
5089 * extents. When the free block is found, ext4_trim_extent is called to TRIM
5090 * the extent.
5091 *
5092 *
5093 * ext4_trim_all_free walks through group's block bitmap searching for free
5094 * extents. When the free extent is found, mark it as used in group buddy
5095 * bitmap. Then issue a TRIM command on this extent and free the extent in
5096 * the group buddy bitmap. This is done until whole group is scanned.
5097 */
5098 static ext4_grpblk_t
ext4_trim_all_free(struct super_block * sb,ext4_group_t group,ext4_grpblk_t start,ext4_grpblk_t max,ext4_grpblk_t minblocks)5099 ext4_trim_all_free(struct super_block *sb, ext4_group_t group,
5100 ext4_grpblk_t start, ext4_grpblk_t max,
5101 ext4_grpblk_t minblocks)
5102 {
5103 void *bitmap;
5104 ext4_grpblk_t next, count = 0, free_count = 0;
5105 struct ext4_buddy e4b;
5106 int ret = 0;
5107
5108 trace_ext4_trim_all_free(sb, group, start, max);
5109
5110 ret = ext4_mb_load_buddy(sb, group, &e4b);
5111 if (ret) {
5112 ext4_error(sb, "Error in loading buddy "
5113 "information for %u", group);
5114 return ret;
5115 }
5116 bitmap = e4b.bd_bitmap;
5117
5118 ext4_lock_group(sb, group);
5119 if (EXT4_MB_GRP_WAS_TRIMMED(e4b.bd_info) &&
5120 minblocks >= atomic_read(&EXT4_SB(sb)->s_last_trim_minblks))
5121 goto out;
5122
5123 start = (e4b.bd_info->bb_first_free > start) ?
5124 e4b.bd_info->bb_first_free : start;
5125
5126 while (start <= max) {
5127 start = mb_find_next_zero_bit(bitmap, max + 1, start);
5128 if (start > max)
5129 break;
5130 next = mb_find_next_bit(bitmap, max + 1, start);
5131
5132 if ((next - start) >= minblocks) {
5133 ret = ext4_trim_extent(sb, start,
5134 next - start, group, &e4b);
5135 if (ret && ret != -EOPNOTSUPP)
5136 break;
5137 ret = 0;
5138 count += next - start;
5139 }
5140 free_count += next - start;
5141 start = next + 1;
5142
5143 if (fatal_signal_pending(current)) {
5144 count = -ERESTARTSYS;
5145 break;
5146 }
5147
5148 if (need_resched()) {
5149 ext4_unlock_group(sb, group);
5150 cond_resched();
5151 ext4_lock_group(sb, group);
5152 }
5153
5154 if ((e4b.bd_info->bb_free - free_count) < minblocks)
5155 break;
5156 }
5157
5158 if (!ret) {
5159 ret = count;
5160 EXT4_MB_GRP_SET_TRIMMED(e4b.bd_info);
5161 }
5162 out:
5163 ext4_unlock_group(sb, group);
5164 ext4_mb_unload_buddy(&e4b);
5165
5166 ext4_debug("trimmed %d blocks in the group %d\n",
5167 count, group);
5168
5169 return ret;
5170 }
5171
5172 /**
5173 * ext4_trim_fs() -- trim ioctl handle function
5174 * @sb: superblock for filesystem
5175 * @range: fstrim_range structure
5176 *
5177 * start: First Byte to trim
5178 * len: number of Bytes to trim from start
5179 * minlen: minimum extent length in Bytes
5180 * ext4_trim_fs goes through all allocation groups containing Bytes from
5181 * start to start+len. For each such a group ext4_trim_all_free function
5182 * is invoked to trim all free space.
5183 */
ext4_trim_fs(struct super_block * sb,struct fstrim_range * range)5184 int ext4_trim_fs(struct super_block *sb, struct fstrim_range *range)
5185 {
5186 struct ext4_group_info *grp;
5187 ext4_group_t group, first_group, last_group;
5188 ext4_grpblk_t cnt = 0, first_cluster, last_cluster;
5189 uint64_t start, end, minlen, trimmed = 0;
5190 ext4_fsblk_t first_data_blk =
5191 le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block);
5192 ext4_fsblk_t max_blks = ext4_blocks_count(EXT4_SB(sb)->s_es);
5193 int ret = 0;
5194
5195 start = range->start >> sb->s_blocksize_bits;
5196 end = start + (range->len >> sb->s_blocksize_bits) - 1;
5197 minlen = EXT4_NUM_B2C(EXT4_SB(sb),
5198 range->minlen >> sb->s_blocksize_bits);
5199
5200 if (minlen > EXT4_CLUSTERS_PER_GROUP(sb) ||
5201 start >= max_blks ||
5202 range->len < sb->s_blocksize)
5203 return -EINVAL;
5204 if (end >= max_blks)
5205 end = max_blks - 1;
5206 if (end <= first_data_blk)
5207 goto out;
5208 if (start < first_data_blk)
5209 start = first_data_blk;
5210
5211 /* Determine first and last group to examine based on start and end */
5212 ext4_get_group_no_and_offset(sb, (ext4_fsblk_t) start,
5213 &first_group, &first_cluster);
5214 ext4_get_group_no_and_offset(sb, (ext4_fsblk_t) end,
5215 &last_group, &last_cluster);
5216
5217 /* end now represents the last cluster to discard in this group */
5218 end = EXT4_CLUSTERS_PER_GROUP(sb) - 1;
5219
5220 for (group = first_group; group <= last_group; group++) {
5221 grp = ext4_get_group_info(sb, group);
5222 /* We only do this if the grp has never been initialized */
5223 if (unlikely(EXT4_MB_GRP_NEED_INIT(grp))) {
5224 ret = ext4_mb_init_group(sb, group);
5225 if (ret)
5226 break;
5227 }
5228
5229 /*
5230 * For all the groups except the last one, last cluster will
5231 * always be EXT4_CLUSTERS_PER_GROUP(sb)-1, so we only need to
5232 * change it for the last group, note that last_cluster is
5233 * already computed earlier by ext4_get_group_no_and_offset()
5234 */
5235 if (group == last_group)
5236 end = last_cluster;
5237
5238 if (grp->bb_free >= minlen) {
5239 cnt = ext4_trim_all_free(sb, group, first_cluster,
5240 end, minlen);
5241 if (cnt < 0) {
5242 ret = cnt;
5243 break;
5244 }
5245 trimmed += cnt;
5246 }
5247
5248 /*
5249 * For every group except the first one, we are sure
5250 * that the first cluster to discard will be cluster #0.
5251 */
5252 first_cluster = 0;
5253 }
5254
5255 if (!ret)
5256 atomic_set(&EXT4_SB(sb)->s_last_trim_minblks, minlen);
5257
5258 out:
5259 range->len = EXT4_C2B(EXT4_SB(sb), trimmed) << sb->s_blocksize_bits;
5260 return ret;
5261 }
5262