1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (c) 2003-2006, Cluster File Systems, Inc, info@clusterfs.com 4 * Written by Alex Tomas <alex@clusterfs.com> 5 */ 6 7 8 /* 9 * mballoc.c contains the multiblocks allocation routines 10 */ 11 12 #include "ext4_jbd2.h" 13 #include "mballoc.h" 14 #include <linux/log2.h> 15 #include <linux/module.h> 16 #include <linux/slab.h> 17 #include <linux/nospec.h> 18 #include <linux/backing-dev.h> 19 #include <linux/freezer.h> 20 #include <trace/events/ext4.h> 21 #include <kunit/static_stub.h> 22 23 /* 24 * MUSTDO: 25 * - test ext4_ext_search_left() and ext4_ext_search_right() 26 * - search for metadata in few groups 27 * 28 * TODO v4: 29 * - normalization should take into account whether file is still open 30 * - discard preallocations if no free space left (policy?) 31 * - don't normalize tails 32 * - quota 33 * - reservation for superuser 34 * 35 * TODO v3: 36 * - bitmap read-ahead (proposed by Oleg Drokin aka green) 37 * - track min/max extents in each group for better group selection 38 * - mb_mark_used() may allocate chunk right after splitting buddy 39 * - tree of groups sorted by number of free blocks 40 * - error handling 41 */ 42 43 /* 44 * The allocation request involve request for multiple number of blocks 45 * near to the goal(block) value specified. 46 * 47 * During initialization phase of the allocator we decide to use the 48 * group preallocation or inode preallocation depending on the size of 49 * the file. The size of the file could be the resulting file size we 50 * would have after allocation, or the current file size, which ever 51 * is larger. If the size is less than sbi->s_mb_stream_request we 52 * select to use the group preallocation. The default value of 53 * s_mb_stream_request is 16 blocks. This can also be tuned via 54 * /sys/fs/ext4/<partition>/mb_stream_req. The value is represented in 55 * terms of number of blocks. 56 * 57 * The main motivation for having small file use group preallocation is to 58 * ensure that we have small files closer together on the disk. 59 * 60 * First stage the allocator looks at the inode prealloc list, 61 * ext4_inode_info->i_prealloc_list, which contains list of prealloc 62 * spaces for this particular inode. The inode prealloc space is 63 * represented as: 64 * 65 * pa_lstart -> the logical start block for this prealloc space 66 * pa_pstart -> the physical start block for this prealloc space 67 * pa_len -> length for this prealloc space (in clusters) 68 * pa_free -> free space available in this prealloc space (in clusters) 69 * 70 * The inode preallocation space is used looking at the _logical_ start 71 * block. If only the logical file block falls within the range of prealloc 72 * space we will consume the particular prealloc space. This makes sure that 73 * we have contiguous physical blocks representing the file blocks 74 * 75 * The important thing to be noted in case of inode prealloc space is that 76 * we don't modify the values associated to inode prealloc space except 77 * pa_free. 78 * 79 * If we are not able to find blocks in the inode prealloc space and if we 80 * have the group allocation flag set then we look at the locality group 81 * prealloc space. These are per CPU prealloc list represented as 82 * 83 * ext4_sb_info.s_locality_groups[smp_processor_id()] 84 * 85 * The reason for having a per cpu locality group is to reduce the contention 86 * between CPUs. It is possible to get scheduled at this point. 87 * 88 * The locality group prealloc space is used looking at whether we have 89 * enough free space (pa_free) within the prealloc space. 90 * 91 * If we can't allocate blocks via inode prealloc or/and locality group 92 * prealloc then we look at the buddy cache. The buddy cache is represented 93 * by ext4_sb_info.s_buddy_cache (struct inode) whose file offset gets 94 * mapped to the buddy and bitmap information regarding different 95 * groups. The buddy information is attached to buddy cache inode so that 96 * we can access them through the page cache. The information regarding 97 * each group is loaded via ext4_mb_load_buddy. The information involve 98 * block bitmap and buddy information. The information are stored in the 99 * inode as: 100 * 101 * { page } 102 * [ group 0 bitmap][ group 0 buddy] [group 1][ group 1]... 103 * 104 * 105 * one block each for bitmap and buddy information. So for each group we 106 * take up 2 blocks. A page can contain blocks_per_page (PAGE_SIZE / 107 * blocksize) blocks. So it can have information regarding groups_per_page 108 * which is blocks_per_page/2 109 * 110 * The buddy cache inode is not stored on disk. The inode is thrown 111 * away when the filesystem is unmounted. 112 * 113 * We look for count number of blocks in the buddy cache. If we were able 114 * to locate that many free blocks we return with additional information 115 * regarding rest of the contiguous physical block available 116 * 117 * Before allocating blocks via buddy cache we normalize the request 118 * blocks. This ensure we ask for more blocks that we needed. The extra 119 * blocks that we get after allocation is added to the respective prealloc 120 * list. In case of inode preallocation we follow a list of heuristics 121 * based on file size. This can be found in ext4_mb_normalize_request. If 122 * we are doing a group prealloc we try to normalize the request to 123 * sbi->s_mb_group_prealloc. The default value of s_mb_group_prealloc is 124 * dependent on the cluster size; for non-bigalloc file systems, it is 125 * 512 blocks. This can be tuned via 126 * /sys/fs/ext4/<partition>/mb_group_prealloc. The value is represented in 127 * terms of number of blocks. If we have mounted the file system with -O 128 * stripe=<value> option the group prealloc request is normalized to the 129 * smallest multiple of the stripe value (sbi->s_stripe) which is 130 * greater than the default mb_group_prealloc. 131 * 132 * If "mb_optimize_scan" mount option is set, we maintain in memory group info 133 * structures in two data structures: 134 * 135 * 1) Array of largest free order lists (sbi->s_mb_largest_free_orders) 136 * 137 * Locking: sbi->s_mb_largest_free_orders_locks(array of rw locks) 138 * 139 * This is an array of lists where the index in the array represents the 140 * largest free order in the buddy bitmap of the participating group infos of 141 * that list. So, there are exactly MB_NUM_ORDERS(sb) (which means total 142 * number of buddy bitmap orders possible) number of lists. Group-infos are 143 * placed in appropriate lists. 144 * 145 * 2) Average fragment size lists (sbi->s_mb_avg_fragment_size) 146 * 147 * Locking: sbi->s_mb_avg_fragment_size_locks(array of rw locks) 148 * 149 * This is an array of lists where in the i-th list there are groups with 150 * average fragment size >= 2^i and < 2^(i+1). The average fragment size 151 * is computed as ext4_group_info->bb_free / ext4_group_info->bb_fragments. 152 * Note that we don't bother with a special list for completely empty groups 153 * so we only have MB_NUM_ORDERS(sb) lists. 154 * 155 * When "mb_optimize_scan" mount option is set, mballoc consults the above data 156 * structures to decide the order in which groups are to be traversed for 157 * fulfilling an allocation request. 158 * 159 * At CR_POWER2_ALIGNED , we look for groups which have the largest_free_order 160 * >= the order of the request. We directly look at the largest free order list 161 * in the data structure (1) above where largest_free_order = order of the 162 * request. If that list is empty, we look at remaining list in the increasing 163 * order of largest_free_order. This allows us to perform CR_POWER2_ALIGNED 164 * lookup in O(1) time. 165 * 166 * At CR_GOAL_LEN_FAST, we only consider groups where 167 * average fragment size > request size. So, we lookup a group which has average 168 * fragment size just above or equal to request size using our average fragment 169 * size group lists (data structure 2) in O(1) time. 170 * 171 * At CR_BEST_AVAIL_LEN, we aim to optimize allocations which can't be satisfied 172 * in CR_GOAL_LEN_FAST. The fact that we couldn't find a group in 173 * CR_GOAL_LEN_FAST suggests that there is no BG that has avg 174 * fragment size > goal length. So before falling to the slower 175 * CR_GOAL_LEN_SLOW, in CR_BEST_AVAIL_LEN we proactively trim goal length and 176 * then use the same fragment lists as CR_GOAL_LEN_FAST to find a BG with a big 177 * enough average fragment size. This increases the chances of finding a 178 * suitable block group in O(1) time and results in faster allocation at the 179 * cost of reduced size of allocation. 180 * 181 * If "mb_optimize_scan" mount option is not set, mballoc traverses groups in 182 * linear order which requires O(N) search time for each CR_POWER2_ALIGNED and 183 * CR_GOAL_LEN_FAST phase. 184 * 185 * The regular allocator (using the buddy cache) supports a few tunables. 186 * 187 * /sys/fs/ext4/<partition>/mb_min_to_scan 188 * /sys/fs/ext4/<partition>/mb_max_to_scan 189 * /sys/fs/ext4/<partition>/mb_order2_req 190 * /sys/fs/ext4/<partition>/mb_linear_limit 191 * 192 * The regular allocator uses buddy scan only if the request len is power of 193 * 2 blocks and the order of allocation is >= sbi->s_mb_order2_reqs. The 194 * value of s_mb_order2_reqs can be tuned via 195 * /sys/fs/ext4/<partition>/mb_order2_req. If the request len is equal to 196 * stripe size (sbi->s_stripe), we try to search for contiguous block in 197 * stripe size. This should result in better allocation on RAID setups. If 198 * not, we search in the specific group using bitmap for best extents. The 199 * tunable min_to_scan and max_to_scan control the behaviour here. 200 * min_to_scan indicate how long the mballoc __must__ look for a best 201 * extent and max_to_scan indicates how long the mballoc __can__ look for a 202 * best extent in the found extents. Searching for the blocks starts with 203 * the group specified as the goal value in allocation context via 204 * ac_g_ex. Each group is first checked based on the criteria whether it 205 * can be used for allocation. ext4_mb_good_group explains how the groups are 206 * checked. 207 * 208 * When "mb_optimize_scan" is turned on, as mentioned above, the groups may not 209 * get traversed linearly. That may result in subsequent allocations being not 210 * close to each other. And so, the underlying device may get filled up in a 211 * non-linear fashion. While that may not matter on non-rotational devices, for 212 * rotational devices that may result in higher seek times. "mb_linear_limit" 213 * tells mballoc how many groups mballoc should search linearly before 214 * performing consulting above data structures for more efficient lookups. For 215 * non rotational devices, this value defaults to 0 and for rotational devices 216 * this is set to MB_DEFAULT_LINEAR_LIMIT. 217 * 218 * Both the prealloc space are getting populated as above. So for the first 219 * request we will hit the buddy cache which will result in this prealloc 220 * space getting filled. The prealloc space is then later used for the 221 * subsequent request. 222 */ 223 224 /* 225 * mballoc operates on the following data: 226 * - on-disk bitmap 227 * - in-core buddy (actually includes buddy and bitmap) 228 * - preallocation descriptors (PAs) 229 * 230 * there are two types of preallocations: 231 * - inode 232 * assiged to specific inode and can be used for this inode only. 233 * it describes part of inode's space preallocated to specific 234 * physical blocks. any block from that preallocated can be used 235 * independent. the descriptor just tracks number of blocks left 236 * unused. so, before taking some block from descriptor, one must 237 * make sure corresponded logical block isn't allocated yet. this 238 * also means that freeing any block within descriptor's range 239 * must discard all preallocated blocks. 240 * - locality group 241 * assigned to specific locality group which does not translate to 242 * permanent set of inodes: inode can join and leave group. space 243 * from this type of preallocation can be used for any inode. thus 244 * it's consumed from the beginning to the end. 245 * 246 * relation between them can be expressed as: 247 * in-core buddy = on-disk bitmap + preallocation descriptors 248 * 249 * this mean blocks mballoc considers used are: 250 * - allocated blocks (persistent) 251 * - preallocated blocks (non-persistent) 252 * 253 * consistency in mballoc world means that at any time a block is either 254 * free or used in ALL structures. notice: "any time" should not be read 255 * literally -- time is discrete and delimited by locks. 256 * 257 * to keep it simple, we don't use block numbers, instead we count number of 258 * blocks: how many blocks marked used/free in on-disk bitmap, buddy and PA. 259 * 260 * all operations can be expressed as: 261 * - init buddy: buddy = on-disk + PAs 262 * - new PA: buddy += N; PA = N 263 * - use inode PA: on-disk += N; PA -= N 264 * - discard inode PA buddy -= on-disk - PA; PA = 0 265 * - use locality group PA on-disk += N; PA -= N 266 * - discard locality group PA buddy -= PA; PA = 0 267 * note: 'buddy -= on-disk - PA' is used to show that on-disk bitmap 268 * is used in real operation because we can't know actual used 269 * bits from PA, only from on-disk bitmap 270 * 271 * if we follow this strict logic, then all operations above should be atomic. 272 * given some of them can block, we'd have to use something like semaphores 273 * killing performance on high-end SMP hardware. let's try to relax it using 274 * the following knowledge: 275 * 1) if buddy is referenced, it's already initialized 276 * 2) while block is used in buddy and the buddy is referenced, 277 * nobody can re-allocate that block 278 * 3) we work on bitmaps and '+' actually means 'set bits'. if on-disk has 279 * bit set and PA claims same block, it's OK. IOW, one can set bit in 280 * on-disk bitmap if buddy has same bit set or/and PA covers corresponded 281 * block 282 * 283 * so, now we're building a concurrency table: 284 * - init buddy vs. 285 * - new PA 286 * blocks for PA are allocated in the buddy, buddy must be referenced 287 * until PA is linked to allocation group to avoid concurrent buddy init 288 * - use inode PA 289 * we need to make sure that either on-disk bitmap or PA has uptodate data 290 * given (3) we care that PA-=N operation doesn't interfere with init 291 * - discard inode PA 292 * the simplest way would be to have buddy initialized by the discard 293 * - use locality group PA 294 * again PA-=N must be serialized with init 295 * - discard locality group PA 296 * the simplest way would be to have buddy initialized by the discard 297 * - new PA vs. 298 * - use inode PA 299 * i_data_sem serializes them 300 * - discard inode PA 301 * discard process must wait until PA isn't used by another process 302 * - use locality group PA 303 * some mutex should serialize them 304 * - discard locality group PA 305 * discard process must wait until PA isn't used by another process 306 * - use inode PA 307 * - use inode PA 308 * i_data_sem or another mutex should serializes them 309 * - discard inode PA 310 * discard process must wait until PA isn't used by another process 311 * - use locality group PA 312 * nothing wrong here -- they're different PAs covering different blocks 313 * - discard locality group PA 314 * discard process must wait until PA isn't used by another process 315 * 316 * now we're ready to make few consequences: 317 * - PA is referenced and while it is no discard is possible 318 * - PA is referenced until block isn't marked in on-disk bitmap 319 * - PA changes only after on-disk bitmap 320 * - discard must not compete with init. either init is done before 321 * any discard or they're serialized somehow 322 * - buddy init as sum of on-disk bitmap and PAs is done atomically 323 * 324 * a special case when we've used PA to emptiness. no need to modify buddy 325 * in this case, but we should care about concurrent init 326 * 327 */ 328 329 /* 330 * Logic in few words: 331 * 332 * - allocation: 333 * load group 334 * find blocks 335 * mark bits in on-disk bitmap 336 * release group 337 * 338 * - use preallocation: 339 * find proper PA (per-inode or group) 340 * load group 341 * mark bits in on-disk bitmap 342 * release group 343 * release PA 344 * 345 * - free: 346 * load group 347 * mark bits in on-disk bitmap 348 * release group 349 * 350 * - discard preallocations in group: 351 * mark PAs deleted 352 * move them onto local list 353 * load on-disk bitmap 354 * load group 355 * remove PA from object (inode or locality group) 356 * mark free blocks in-core 357 * 358 * - discard inode's preallocations: 359 */ 360 361 /* 362 * Locking rules 363 * 364 * Locks: 365 * - bitlock on a group (group) 366 * - object (inode/locality) (object) 367 * - per-pa lock (pa) 368 * - cr_power2_aligned lists lock (cr_power2_aligned) 369 * - cr_goal_len_fast lists lock (cr_goal_len_fast) 370 * 371 * Paths: 372 * - new pa 373 * object 374 * group 375 * 376 * - find and use pa: 377 * pa 378 * 379 * - release consumed pa: 380 * pa 381 * group 382 * object 383 * 384 * - generate in-core bitmap: 385 * group 386 * pa 387 * 388 * - discard all for given object (inode, locality group): 389 * object 390 * pa 391 * group 392 * 393 * - discard all for given group: 394 * group 395 * pa 396 * group 397 * object 398 * 399 * - allocation path (ext4_mb_regular_allocator) 400 * group 401 * cr_power2_aligned/cr_goal_len_fast 402 */ 403 static struct kmem_cache *ext4_pspace_cachep; 404 static struct kmem_cache *ext4_ac_cachep; 405 static struct kmem_cache *ext4_free_data_cachep; 406 407 /* We create slab caches for groupinfo data structures based on the 408 * superblock block size. There will be one per mounted filesystem for 409 * each unique s_blocksize_bits */ 410 #define NR_GRPINFO_CACHES 8 411 static struct kmem_cache *ext4_groupinfo_caches[NR_GRPINFO_CACHES]; 412 413 static const char * const ext4_groupinfo_slab_names[NR_GRPINFO_CACHES] = { 414 "ext4_groupinfo_1k", "ext4_groupinfo_2k", "ext4_groupinfo_4k", 415 "ext4_groupinfo_8k", "ext4_groupinfo_16k", "ext4_groupinfo_32k", 416 "ext4_groupinfo_64k", "ext4_groupinfo_128k" 417 }; 418 419 static void ext4_mb_generate_from_pa(struct super_block *sb, void *bitmap, 420 ext4_group_t group); 421 static void ext4_mb_new_preallocation(struct ext4_allocation_context *ac); 422 423 static bool ext4_mb_good_group(struct ext4_allocation_context *ac, 424 ext4_group_t group, enum criteria cr); 425 426 static int ext4_try_to_trim_range(struct super_block *sb, 427 struct ext4_buddy *e4b, ext4_grpblk_t start, 428 ext4_grpblk_t max, ext4_grpblk_t minblocks); 429 430 /* 431 * The algorithm using this percpu seq counter goes below: 432 * 1. We sample the percpu discard_pa_seq counter before trying for block 433 * allocation in ext4_mb_new_blocks(). 434 * 2. We increment this percpu discard_pa_seq counter when we either allocate 435 * or free these blocks i.e. while marking those blocks as used/free in 436 * mb_mark_used()/mb_free_blocks(). 437 * 3. We also increment this percpu seq counter when we successfully identify 438 * that the bb_prealloc_list is not empty and hence proceed for discarding 439 * of those PAs inside ext4_mb_discard_group_preallocations(). 440 * 441 * Now to make sure that the regular fast path of block allocation is not 442 * affected, as a small optimization we only sample the percpu seq counter 443 * on that cpu. Only when the block allocation fails and when freed blocks 444 * found were 0, that is when we sample percpu seq counter for all cpus using 445 * below function ext4_get_discard_pa_seq_sum(). This happens after making 446 * sure that all the PAs on grp->bb_prealloc_list got freed or if it's empty. 447 */ 448 static DEFINE_PER_CPU(u64, discard_pa_seq); 449 static inline u64 ext4_get_discard_pa_seq_sum(void) 450 { 451 int __cpu; 452 u64 __seq = 0; 453 454 for_each_possible_cpu(__cpu) 455 __seq += per_cpu(discard_pa_seq, __cpu); 456 return __seq; 457 } 458 459 static inline void *mb_correct_addr_and_bit(int *bit, void *addr) 460 { 461 #if BITS_PER_LONG == 64 462 *bit += ((unsigned long) addr & 7UL) << 3; 463 addr = (void *) ((unsigned long) addr & ~7UL); 464 #elif BITS_PER_LONG == 32 465 *bit += ((unsigned long) addr & 3UL) << 3; 466 addr = (void *) ((unsigned long) addr & ~3UL); 467 #else 468 #error "how many bits you are?!" 469 #endif 470 return addr; 471 } 472 473 static inline int mb_test_bit(int bit, void *addr) 474 { 475 /* 476 * ext4_test_bit on architecture like powerpc 477 * needs unsigned long aligned address 478 */ 479 addr = mb_correct_addr_and_bit(&bit, addr); 480 return ext4_test_bit(bit, addr); 481 } 482 483 static inline void mb_set_bit(int bit, void *addr) 484 { 485 addr = mb_correct_addr_and_bit(&bit, addr); 486 ext4_set_bit(bit, addr); 487 } 488 489 static inline void mb_clear_bit(int bit, void *addr) 490 { 491 addr = mb_correct_addr_and_bit(&bit, addr); 492 ext4_clear_bit(bit, addr); 493 } 494 495 static inline int mb_test_and_clear_bit(int bit, void *addr) 496 { 497 addr = mb_correct_addr_and_bit(&bit, addr); 498 return ext4_test_and_clear_bit(bit, addr); 499 } 500 501 static inline int mb_find_next_zero_bit(void *addr, int max, int start) 502 { 503 int fix = 0, ret, tmpmax; 504 addr = mb_correct_addr_and_bit(&fix, addr); 505 tmpmax = max + fix; 506 start += fix; 507 508 ret = ext4_find_next_zero_bit(addr, tmpmax, start) - fix; 509 if (ret > max) 510 return max; 511 return ret; 512 } 513 514 static inline int mb_find_next_bit(void *addr, int max, int start) 515 { 516 int fix = 0, ret, tmpmax; 517 addr = mb_correct_addr_and_bit(&fix, addr); 518 tmpmax = max + fix; 519 start += fix; 520 521 ret = ext4_find_next_bit(addr, tmpmax, start) - fix; 522 if (ret > max) 523 return max; 524 return ret; 525 } 526 527 static void *mb_find_buddy(struct ext4_buddy *e4b, int order, int *max) 528 { 529 char *bb; 530 531 BUG_ON(e4b->bd_bitmap == e4b->bd_buddy); 532 BUG_ON(max == NULL); 533 534 if (order > e4b->bd_blkbits + 1) { 535 *max = 0; 536 return NULL; 537 } 538 539 /* at order 0 we see each particular block */ 540 if (order == 0) { 541 *max = 1 << (e4b->bd_blkbits + 3); 542 return e4b->bd_bitmap; 543 } 544 545 bb = e4b->bd_buddy + EXT4_SB(e4b->bd_sb)->s_mb_offsets[order]; 546 *max = EXT4_SB(e4b->bd_sb)->s_mb_maxs[order]; 547 548 return bb; 549 } 550 551 #ifdef DOUBLE_CHECK 552 static void mb_free_blocks_double(struct inode *inode, struct ext4_buddy *e4b, 553 int first, int count) 554 { 555 int i; 556 struct super_block *sb = e4b->bd_sb; 557 558 if (unlikely(e4b->bd_info->bb_bitmap == NULL)) 559 return; 560 assert_spin_locked(ext4_group_lock_ptr(sb, e4b->bd_group)); 561 for (i = 0; i < count; i++) { 562 if (!mb_test_bit(first + i, e4b->bd_info->bb_bitmap)) { 563 ext4_fsblk_t blocknr; 564 565 blocknr = ext4_group_first_block_no(sb, e4b->bd_group); 566 blocknr += EXT4_C2B(EXT4_SB(sb), first + i); 567 ext4_grp_locked_error(sb, e4b->bd_group, 568 inode ? inode->i_ino : 0, 569 blocknr, 570 "freeing block already freed " 571 "(bit %u)", 572 first + i); 573 ext4_mark_group_bitmap_corrupted(sb, e4b->bd_group, 574 EXT4_GROUP_INFO_BBITMAP_CORRUPT); 575 } 576 mb_clear_bit(first + i, e4b->bd_info->bb_bitmap); 577 } 578 } 579 580 static void mb_mark_used_double(struct ext4_buddy *e4b, int first, int count) 581 { 582 int i; 583 584 if (unlikely(e4b->bd_info->bb_bitmap == NULL)) 585 return; 586 assert_spin_locked(ext4_group_lock_ptr(e4b->bd_sb, e4b->bd_group)); 587 for (i = 0; i < count; i++) { 588 BUG_ON(mb_test_bit(first + i, e4b->bd_info->bb_bitmap)); 589 mb_set_bit(first + i, e4b->bd_info->bb_bitmap); 590 } 591 } 592 593 static void mb_cmp_bitmaps(struct ext4_buddy *e4b, void *bitmap) 594 { 595 if (unlikely(e4b->bd_info->bb_bitmap == NULL)) 596 return; 597 if (memcmp(e4b->bd_info->bb_bitmap, bitmap, e4b->bd_sb->s_blocksize)) { 598 unsigned char *b1, *b2; 599 int i; 600 b1 = (unsigned char *) e4b->bd_info->bb_bitmap; 601 b2 = (unsigned char *) bitmap; 602 for (i = 0; i < e4b->bd_sb->s_blocksize; i++) { 603 if (b1[i] != b2[i]) { 604 ext4_msg(e4b->bd_sb, KERN_ERR, 605 "corruption in group %u " 606 "at byte %u(%u): %x in copy != %x " 607 "on disk/prealloc", 608 e4b->bd_group, i, i * 8, b1[i], b2[i]); 609 BUG(); 610 } 611 } 612 } 613 } 614 615 static void mb_group_bb_bitmap_alloc(struct super_block *sb, 616 struct ext4_group_info *grp, ext4_group_t group) 617 { 618 struct buffer_head *bh; 619 620 grp->bb_bitmap = kmalloc(sb->s_blocksize, GFP_NOFS); 621 if (!grp->bb_bitmap) 622 return; 623 624 bh = ext4_read_block_bitmap(sb, group); 625 if (IS_ERR_OR_NULL(bh)) { 626 kfree(grp->bb_bitmap); 627 grp->bb_bitmap = NULL; 628 return; 629 } 630 631 memcpy(grp->bb_bitmap, bh->b_data, sb->s_blocksize); 632 put_bh(bh); 633 } 634 635 static void mb_group_bb_bitmap_free(struct ext4_group_info *grp) 636 { 637 kfree(grp->bb_bitmap); 638 } 639 640 #else 641 static inline void mb_free_blocks_double(struct inode *inode, 642 struct ext4_buddy *e4b, int first, int count) 643 { 644 return; 645 } 646 static inline void mb_mark_used_double(struct ext4_buddy *e4b, 647 int first, int count) 648 { 649 return; 650 } 651 static inline void mb_cmp_bitmaps(struct ext4_buddy *e4b, void *bitmap) 652 { 653 return; 654 } 655 656 static inline void mb_group_bb_bitmap_alloc(struct super_block *sb, 657 struct ext4_group_info *grp, ext4_group_t group) 658 { 659 return; 660 } 661 662 static inline void mb_group_bb_bitmap_free(struct ext4_group_info *grp) 663 { 664 return; 665 } 666 #endif 667 668 #ifdef AGGRESSIVE_CHECK 669 670 #define MB_CHECK_ASSERT(assert) \ 671 do { \ 672 if (!(assert)) { \ 673 printk(KERN_EMERG \ 674 "Assertion failure in %s() at %s:%d: \"%s\"\n", \ 675 function, file, line, # assert); \ 676 BUG(); \ 677 } \ 678 } while (0) 679 680 static int __mb_check_buddy(struct ext4_buddy *e4b, char *file, 681 const char *function, int line) 682 { 683 struct super_block *sb = e4b->bd_sb; 684 int order = e4b->bd_blkbits + 1; 685 int max; 686 int max2; 687 int i; 688 int j; 689 int k; 690 int count; 691 struct ext4_group_info *grp; 692 int fragments = 0; 693 int fstart; 694 struct list_head *cur; 695 void *buddy; 696 void *buddy2; 697 698 if (e4b->bd_info->bb_check_counter++ % 10) 699 return 0; 700 701 while (order > 1) { 702 buddy = mb_find_buddy(e4b, order, &max); 703 MB_CHECK_ASSERT(buddy); 704 buddy2 = mb_find_buddy(e4b, order - 1, &max2); 705 MB_CHECK_ASSERT(buddy2); 706 MB_CHECK_ASSERT(buddy != buddy2); 707 MB_CHECK_ASSERT(max * 2 == max2); 708 709 count = 0; 710 for (i = 0; i < max; i++) { 711 712 if (mb_test_bit(i, buddy)) { 713 /* only single bit in buddy2 may be 0 */ 714 if (!mb_test_bit(i << 1, buddy2)) { 715 MB_CHECK_ASSERT( 716 mb_test_bit((i<<1)+1, buddy2)); 717 } 718 continue; 719 } 720 721 /* both bits in buddy2 must be 1 */ 722 MB_CHECK_ASSERT(mb_test_bit(i << 1, buddy2)); 723 MB_CHECK_ASSERT(mb_test_bit((i << 1) + 1, buddy2)); 724 725 for (j = 0; j < (1 << order); j++) { 726 k = (i * (1 << order)) + j; 727 MB_CHECK_ASSERT( 728 !mb_test_bit(k, e4b->bd_bitmap)); 729 } 730 count++; 731 } 732 MB_CHECK_ASSERT(e4b->bd_info->bb_counters[order] == count); 733 order--; 734 } 735 736 fstart = -1; 737 buddy = mb_find_buddy(e4b, 0, &max); 738 for (i = 0; i < max; i++) { 739 if (!mb_test_bit(i, buddy)) { 740 MB_CHECK_ASSERT(i >= e4b->bd_info->bb_first_free); 741 if (fstart == -1) { 742 fragments++; 743 fstart = i; 744 } 745 continue; 746 } 747 fstart = -1; 748 /* check used bits only */ 749 for (j = 0; j < e4b->bd_blkbits + 1; j++) { 750 buddy2 = mb_find_buddy(e4b, j, &max2); 751 k = i >> j; 752 MB_CHECK_ASSERT(k < max2); 753 MB_CHECK_ASSERT(mb_test_bit(k, buddy2)); 754 } 755 } 756 MB_CHECK_ASSERT(!EXT4_MB_GRP_NEED_INIT(e4b->bd_info)); 757 MB_CHECK_ASSERT(e4b->bd_info->bb_fragments == fragments); 758 759 grp = ext4_get_group_info(sb, e4b->bd_group); 760 if (!grp) 761 return NULL; 762 list_for_each(cur, &grp->bb_prealloc_list) { 763 ext4_group_t groupnr; 764 struct ext4_prealloc_space *pa; 765 pa = list_entry(cur, struct ext4_prealloc_space, pa_group_list); 766 ext4_get_group_no_and_offset(sb, pa->pa_pstart, &groupnr, &k); 767 MB_CHECK_ASSERT(groupnr == e4b->bd_group); 768 for (i = 0; i < pa->pa_len; i++) 769 MB_CHECK_ASSERT(mb_test_bit(k + i, buddy)); 770 } 771 return 0; 772 } 773 #undef MB_CHECK_ASSERT 774 #define mb_check_buddy(e4b) __mb_check_buddy(e4b, \ 775 __FILE__, __func__, __LINE__) 776 #else 777 #define mb_check_buddy(e4b) 778 #endif 779 780 /* 781 * Divide blocks started from @first with length @len into 782 * smaller chunks with power of 2 blocks. 783 * Clear the bits in bitmap which the blocks of the chunk(s) covered, 784 * then increase bb_counters[] for corresponded chunk size. 785 */ 786 static void ext4_mb_mark_free_simple(struct super_block *sb, 787 void *buddy, ext4_grpblk_t first, ext4_grpblk_t len, 788 struct ext4_group_info *grp) 789 { 790 struct ext4_sb_info *sbi = EXT4_SB(sb); 791 ext4_grpblk_t min; 792 ext4_grpblk_t max; 793 ext4_grpblk_t chunk; 794 unsigned int border; 795 796 BUG_ON(len > EXT4_CLUSTERS_PER_GROUP(sb)); 797 798 border = 2 << sb->s_blocksize_bits; 799 800 while (len > 0) { 801 /* find how many blocks can be covered since this position */ 802 max = ffs(first | border) - 1; 803 804 /* find how many blocks of power 2 we need to mark */ 805 min = fls(len) - 1; 806 807 if (max < min) 808 min = max; 809 chunk = 1 << min; 810 811 /* mark multiblock chunks only */ 812 grp->bb_counters[min]++; 813 if (min > 0) 814 mb_clear_bit(first >> min, 815 buddy + sbi->s_mb_offsets[min]); 816 817 len -= chunk; 818 first += chunk; 819 } 820 } 821 822 static int mb_avg_fragment_size_order(struct super_block *sb, ext4_grpblk_t len) 823 { 824 int order; 825 826 /* 827 * We don't bother with a special lists groups with only 1 block free 828 * extents and for completely empty groups. 829 */ 830 order = fls(len) - 2; 831 if (order < 0) 832 return 0; 833 if (order == MB_NUM_ORDERS(sb)) 834 order--; 835 return order; 836 } 837 838 /* Move group to appropriate avg_fragment_size list */ 839 static void 840 mb_update_avg_fragment_size(struct super_block *sb, struct ext4_group_info *grp) 841 { 842 struct ext4_sb_info *sbi = EXT4_SB(sb); 843 int new_order; 844 845 if (!test_opt2(sb, MB_OPTIMIZE_SCAN) || grp->bb_free == 0) 846 return; 847 848 new_order = mb_avg_fragment_size_order(sb, 849 grp->bb_free / grp->bb_fragments); 850 if (new_order == grp->bb_avg_fragment_size_order) 851 return; 852 853 if (grp->bb_avg_fragment_size_order != -1) { 854 write_lock(&sbi->s_mb_avg_fragment_size_locks[ 855 grp->bb_avg_fragment_size_order]); 856 list_del(&grp->bb_avg_fragment_size_node); 857 write_unlock(&sbi->s_mb_avg_fragment_size_locks[ 858 grp->bb_avg_fragment_size_order]); 859 } 860 grp->bb_avg_fragment_size_order = new_order; 861 write_lock(&sbi->s_mb_avg_fragment_size_locks[ 862 grp->bb_avg_fragment_size_order]); 863 list_add_tail(&grp->bb_avg_fragment_size_node, 864 &sbi->s_mb_avg_fragment_size[grp->bb_avg_fragment_size_order]); 865 write_unlock(&sbi->s_mb_avg_fragment_size_locks[ 866 grp->bb_avg_fragment_size_order]); 867 } 868 869 /* 870 * Choose next group by traversing largest_free_order lists. Updates *new_cr if 871 * cr level needs an update. 872 */ 873 static void ext4_mb_choose_next_group_p2_aligned(struct ext4_allocation_context *ac, 874 enum criteria *new_cr, ext4_group_t *group, ext4_group_t ngroups) 875 { 876 struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb); 877 struct ext4_group_info *iter; 878 int i; 879 880 if (ac->ac_status == AC_STATUS_FOUND) 881 return; 882 883 if (unlikely(sbi->s_mb_stats && ac->ac_flags & EXT4_MB_CR_POWER2_ALIGNED_OPTIMIZED)) 884 atomic_inc(&sbi->s_bal_p2_aligned_bad_suggestions); 885 886 for (i = ac->ac_2order; i < MB_NUM_ORDERS(ac->ac_sb); i++) { 887 if (list_empty(&sbi->s_mb_largest_free_orders[i])) 888 continue; 889 read_lock(&sbi->s_mb_largest_free_orders_locks[i]); 890 if (list_empty(&sbi->s_mb_largest_free_orders[i])) { 891 read_unlock(&sbi->s_mb_largest_free_orders_locks[i]); 892 continue; 893 } 894 list_for_each_entry(iter, &sbi->s_mb_largest_free_orders[i], 895 bb_largest_free_order_node) { 896 if (sbi->s_mb_stats) 897 atomic64_inc(&sbi->s_bal_cX_groups_considered[CR_POWER2_ALIGNED]); 898 if (likely(ext4_mb_good_group(ac, iter->bb_group, CR_POWER2_ALIGNED))) { 899 *group = iter->bb_group; 900 ac->ac_flags |= EXT4_MB_CR_POWER2_ALIGNED_OPTIMIZED; 901 read_unlock(&sbi->s_mb_largest_free_orders_locks[i]); 902 return; 903 } 904 } 905 read_unlock(&sbi->s_mb_largest_free_orders_locks[i]); 906 } 907 908 /* Increment cr and search again if no group is found */ 909 *new_cr = CR_GOAL_LEN_FAST; 910 } 911 912 /* 913 * Find a suitable group of given order from the average fragments list. 914 */ 915 static struct ext4_group_info * 916 ext4_mb_find_good_group_avg_frag_lists(struct ext4_allocation_context *ac, int order) 917 { 918 struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb); 919 struct list_head *frag_list = &sbi->s_mb_avg_fragment_size[order]; 920 rwlock_t *frag_list_lock = &sbi->s_mb_avg_fragment_size_locks[order]; 921 struct ext4_group_info *grp = NULL, *iter; 922 enum criteria cr = ac->ac_criteria; 923 924 if (list_empty(frag_list)) 925 return NULL; 926 read_lock(frag_list_lock); 927 if (list_empty(frag_list)) { 928 read_unlock(frag_list_lock); 929 return NULL; 930 } 931 list_for_each_entry(iter, frag_list, bb_avg_fragment_size_node) { 932 if (sbi->s_mb_stats) 933 atomic64_inc(&sbi->s_bal_cX_groups_considered[cr]); 934 if (likely(ext4_mb_good_group(ac, iter->bb_group, cr))) { 935 grp = iter; 936 break; 937 } 938 } 939 read_unlock(frag_list_lock); 940 return grp; 941 } 942 943 /* 944 * Choose next group by traversing average fragment size list of suitable 945 * order. Updates *new_cr if cr level needs an update. 946 */ 947 static void ext4_mb_choose_next_group_goal_fast(struct ext4_allocation_context *ac, 948 enum criteria *new_cr, ext4_group_t *group, ext4_group_t ngroups) 949 { 950 struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb); 951 struct ext4_group_info *grp = NULL; 952 int i; 953 954 if (unlikely(ac->ac_flags & EXT4_MB_CR_GOAL_LEN_FAST_OPTIMIZED)) { 955 if (sbi->s_mb_stats) 956 atomic_inc(&sbi->s_bal_goal_fast_bad_suggestions); 957 } 958 959 for (i = mb_avg_fragment_size_order(ac->ac_sb, ac->ac_g_ex.fe_len); 960 i < MB_NUM_ORDERS(ac->ac_sb); i++) { 961 grp = ext4_mb_find_good_group_avg_frag_lists(ac, i); 962 if (grp) { 963 *group = grp->bb_group; 964 ac->ac_flags |= EXT4_MB_CR_GOAL_LEN_FAST_OPTIMIZED; 965 return; 966 } 967 } 968 969 /* 970 * CR_BEST_AVAIL_LEN works based on the concept that we have 971 * a larger normalized goal len request which can be trimmed to 972 * a smaller goal len such that it can still satisfy original 973 * request len. However, allocation request for non-regular 974 * files never gets normalized. 975 * See function ext4_mb_normalize_request() (EXT4_MB_HINT_DATA). 976 */ 977 if (ac->ac_flags & EXT4_MB_HINT_DATA) 978 *new_cr = CR_BEST_AVAIL_LEN; 979 else 980 *new_cr = CR_GOAL_LEN_SLOW; 981 } 982 983 /* 984 * We couldn't find a group in CR_GOAL_LEN_FAST so try to find the highest free fragment 985 * order we have and proactively trim the goal request length to that order to 986 * find a suitable group faster. 987 * 988 * This optimizes allocation speed at the cost of slightly reduced 989 * preallocations. However, we make sure that we don't trim the request too 990 * much and fall to CR_GOAL_LEN_SLOW in that case. 991 */ 992 static void ext4_mb_choose_next_group_best_avail(struct ext4_allocation_context *ac, 993 enum criteria *new_cr, ext4_group_t *group, ext4_group_t ngroups) 994 { 995 struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb); 996 struct ext4_group_info *grp = NULL; 997 int i, order, min_order; 998 unsigned long num_stripe_clusters = 0; 999 1000 if (unlikely(ac->ac_flags & EXT4_MB_CR_BEST_AVAIL_LEN_OPTIMIZED)) { 1001 if (sbi->s_mb_stats) 1002 atomic_inc(&sbi->s_bal_best_avail_bad_suggestions); 1003 } 1004 1005 /* 1006 * mb_avg_fragment_size_order() returns order in a way that makes 1007 * retrieving back the length using (1 << order) inaccurate. Hence, use 1008 * fls() instead since we need to know the actual length while modifying 1009 * goal length. 1010 */ 1011 order = fls(ac->ac_g_ex.fe_len) - 1; 1012 min_order = order - sbi->s_mb_best_avail_max_trim_order; 1013 if (min_order < 0) 1014 min_order = 0; 1015 1016 if (sbi->s_stripe > 0) { 1017 /* 1018 * We are assuming that stripe size is always a multiple of 1019 * cluster ratio otherwise __ext4_fill_super exists early. 1020 */ 1021 num_stripe_clusters = EXT4_NUM_B2C(sbi, sbi->s_stripe); 1022 if (1 << min_order < num_stripe_clusters) 1023 /* 1024 * We consider 1 order less because later we round 1025 * up the goal len to num_stripe_clusters 1026 */ 1027 min_order = fls(num_stripe_clusters) - 1; 1028 } 1029 1030 if (1 << min_order < ac->ac_o_ex.fe_len) 1031 min_order = fls(ac->ac_o_ex.fe_len); 1032 1033 for (i = order; i >= min_order; i--) { 1034 int frag_order; 1035 /* 1036 * Scale down goal len to make sure we find something 1037 * in the free fragments list. Basically, reduce 1038 * preallocations. 1039 */ 1040 ac->ac_g_ex.fe_len = 1 << i; 1041 1042 if (num_stripe_clusters > 0) { 1043 /* 1044 * Try to round up the adjusted goal length to 1045 * stripe size (in cluster units) multiple for 1046 * efficiency. 1047 */ 1048 ac->ac_g_ex.fe_len = roundup(ac->ac_g_ex.fe_len, 1049 num_stripe_clusters); 1050 } 1051 1052 frag_order = mb_avg_fragment_size_order(ac->ac_sb, 1053 ac->ac_g_ex.fe_len); 1054 1055 grp = ext4_mb_find_good_group_avg_frag_lists(ac, frag_order); 1056 if (grp) { 1057 *group = grp->bb_group; 1058 ac->ac_flags |= EXT4_MB_CR_BEST_AVAIL_LEN_OPTIMIZED; 1059 return; 1060 } 1061 } 1062 1063 /* Reset goal length to original goal length before falling into CR_GOAL_LEN_SLOW */ 1064 ac->ac_g_ex.fe_len = ac->ac_orig_goal_len; 1065 *new_cr = CR_GOAL_LEN_SLOW; 1066 } 1067 1068 static inline int should_optimize_scan(struct ext4_allocation_context *ac) 1069 { 1070 if (unlikely(!test_opt2(ac->ac_sb, MB_OPTIMIZE_SCAN))) 1071 return 0; 1072 if (ac->ac_criteria >= CR_GOAL_LEN_SLOW) 1073 return 0; 1074 if (!ext4_test_inode_flag(ac->ac_inode, EXT4_INODE_EXTENTS)) 1075 return 0; 1076 return 1; 1077 } 1078 1079 /* 1080 * Return next linear group for allocation. If linear traversal should not be 1081 * performed, this function just returns the same group 1082 */ 1083 static ext4_group_t 1084 next_linear_group(struct ext4_allocation_context *ac, ext4_group_t group, 1085 ext4_group_t ngroups) 1086 { 1087 if (!should_optimize_scan(ac)) 1088 goto inc_and_return; 1089 1090 if (ac->ac_groups_linear_remaining) { 1091 ac->ac_groups_linear_remaining--; 1092 goto inc_and_return; 1093 } 1094 1095 return group; 1096 inc_and_return: 1097 /* 1098 * Artificially restricted ngroups for non-extent 1099 * files makes group > ngroups possible on first loop. 1100 */ 1101 return group + 1 >= ngroups ? 0 : group + 1; 1102 } 1103 1104 /* 1105 * ext4_mb_choose_next_group: choose next group for allocation. 1106 * 1107 * @ac Allocation Context 1108 * @new_cr This is an output parameter. If the there is no good group 1109 * available at current CR level, this field is updated to indicate 1110 * the new cr level that should be used. 1111 * @group This is an input / output parameter. As an input it indicates the 1112 * next group that the allocator intends to use for allocation. As 1113 * output, this field indicates the next group that should be used as 1114 * determined by the optimization functions. 1115 * @ngroups Total number of groups 1116 */ 1117 static void ext4_mb_choose_next_group(struct ext4_allocation_context *ac, 1118 enum criteria *new_cr, ext4_group_t *group, ext4_group_t ngroups) 1119 { 1120 *new_cr = ac->ac_criteria; 1121 1122 if (!should_optimize_scan(ac) || ac->ac_groups_linear_remaining) { 1123 *group = next_linear_group(ac, *group, ngroups); 1124 return; 1125 } 1126 1127 if (*new_cr == CR_POWER2_ALIGNED) { 1128 ext4_mb_choose_next_group_p2_aligned(ac, new_cr, group, ngroups); 1129 } else if (*new_cr == CR_GOAL_LEN_FAST) { 1130 ext4_mb_choose_next_group_goal_fast(ac, new_cr, group, ngroups); 1131 } else if (*new_cr == CR_BEST_AVAIL_LEN) { 1132 ext4_mb_choose_next_group_best_avail(ac, new_cr, group, ngroups); 1133 } else { 1134 /* 1135 * TODO: For CR=2, we can arrange groups in an rb tree sorted by 1136 * bb_free. But until that happens, we should never come here. 1137 */ 1138 WARN_ON(1); 1139 } 1140 } 1141 1142 /* 1143 * Cache the order of the largest free extent we have available in this block 1144 * group. 1145 */ 1146 static void 1147 mb_set_largest_free_order(struct super_block *sb, struct ext4_group_info *grp) 1148 { 1149 struct ext4_sb_info *sbi = EXT4_SB(sb); 1150 int i; 1151 1152 for (i = MB_NUM_ORDERS(sb) - 1; i >= 0; i--) 1153 if (grp->bb_counters[i] > 0) 1154 break; 1155 /* No need to move between order lists? */ 1156 if (!test_opt2(sb, MB_OPTIMIZE_SCAN) || 1157 i == grp->bb_largest_free_order) { 1158 grp->bb_largest_free_order = i; 1159 return; 1160 } 1161 1162 if (grp->bb_largest_free_order >= 0) { 1163 write_lock(&sbi->s_mb_largest_free_orders_locks[ 1164 grp->bb_largest_free_order]); 1165 list_del_init(&grp->bb_largest_free_order_node); 1166 write_unlock(&sbi->s_mb_largest_free_orders_locks[ 1167 grp->bb_largest_free_order]); 1168 } 1169 grp->bb_largest_free_order = i; 1170 if (grp->bb_largest_free_order >= 0 && grp->bb_free) { 1171 write_lock(&sbi->s_mb_largest_free_orders_locks[ 1172 grp->bb_largest_free_order]); 1173 list_add_tail(&grp->bb_largest_free_order_node, 1174 &sbi->s_mb_largest_free_orders[grp->bb_largest_free_order]); 1175 write_unlock(&sbi->s_mb_largest_free_orders_locks[ 1176 grp->bb_largest_free_order]); 1177 } 1178 } 1179 1180 static noinline_for_stack 1181 void ext4_mb_generate_buddy(struct super_block *sb, 1182 void *buddy, void *bitmap, ext4_group_t group, 1183 struct ext4_group_info *grp) 1184 { 1185 struct ext4_sb_info *sbi = EXT4_SB(sb); 1186 ext4_grpblk_t max = EXT4_CLUSTERS_PER_GROUP(sb); 1187 ext4_grpblk_t i = 0; 1188 ext4_grpblk_t first; 1189 ext4_grpblk_t len; 1190 unsigned free = 0; 1191 unsigned fragments = 0; 1192 unsigned long long period = get_cycles(); 1193 1194 /* initialize buddy from bitmap which is aggregation 1195 * of on-disk bitmap and preallocations */ 1196 i = mb_find_next_zero_bit(bitmap, max, 0); 1197 grp->bb_first_free = i; 1198 while (i < max) { 1199 fragments++; 1200 first = i; 1201 i = mb_find_next_bit(bitmap, max, i); 1202 len = i - first; 1203 free += len; 1204 if (len > 1) 1205 ext4_mb_mark_free_simple(sb, buddy, first, len, grp); 1206 else 1207 grp->bb_counters[0]++; 1208 if (i < max) 1209 i = mb_find_next_zero_bit(bitmap, max, i); 1210 } 1211 grp->bb_fragments = fragments; 1212 1213 if (free != grp->bb_free) { 1214 ext4_grp_locked_error(sb, group, 0, 0, 1215 "block bitmap and bg descriptor " 1216 "inconsistent: %u vs %u free clusters", 1217 free, grp->bb_free); 1218 /* 1219 * If we intend to continue, we consider group descriptor 1220 * corrupt and update bb_free using bitmap value 1221 */ 1222 grp->bb_free = free; 1223 ext4_mark_group_bitmap_corrupted(sb, group, 1224 EXT4_GROUP_INFO_BBITMAP_CORRUPT); 1225 } 1226 mb_set_largest_free_order(sb, grp); 1227 mb_update_avg_fragment_size(sb, grp); 1228 1229 clear_bit(EXT4_GROUP_INFO_NEED_INIT_BIT, &(grp->bb_state)); 1230 1231 period = get_cycles() - period; 1232 atomic_inc(&sbi->s_mb_buddies_generated); 1233 atomic64_add(period, &sbi->s_mb_generation_time); 1234 } 1235 1236 /* The buddy information is attached the buddy cache inode 1237 * for convenience. The information regarding each group 1238 * is loaded via ext4_mb_load_buddy. The information involve 1239 * block bitmap and buddy information. The information are 1240 * stored in the inode as 1241 * 1242 * { page } 1243 * [ group 0 bitmap][ group 0 buddy] [group 1][ group 1]... 1244 * 1245 * 1246 * one block each for bitmap and buddy information. 1247 * So for each group we take up 2 blocks. A page can 1248 * contain blocks_per_page (PAGE_SIZE / blocksize) blocks. 1249 * So it can have information regarding groups_per_page which 1250 * is blocks_per_page/2 1251 * 1252 * Locking note: This routine takes the block group lock of all groups 1253 * for this page; do not hold this lock when calling this routine! 1254 */ 1255 1256 static int ext4_mb_init_cache(struct page *page, char *incore, gfp_t gfp) 1257 { 1258 ext4_group_t ngroups; 1259 unsigned int blocksize; 1260 int blocks_per_page; 1261 int groups_per_page; 1262 int err = 0; 1263 int i; 1264 ext4_group_t first_group, group; 1265 int first_block; 1266 struct super_block *sb; 1267 struct buffer_head *bhs; 1268 struct buffer_head **bh = NULL; 1269 struct inode *inode; 1270 char *data; 1271 char *bitmap; 1272 struct ext4_group_info *grinfo; 1273 1274 inode = page->mapping->host; 1275 sb = inode->i_sb; 1276 ngroups = ext4_get_groups_count(sb); 1277 blocksize = i_blocksize(inode); 1278 blocks_per_page = PAGE_SIZE / blocksize; 1279 1280 mb_debug(sb, "init page %lu\n", page->index); 1281 1282 groups_per_page = blocks_per_page >> 1; 1283 if (groups_per_page == 0) 1284 groups_per_page = 1; 1285 1286 /* allocate buffer_heads to read bitmaps */ 1287 if (groups_per_page > 1) { 1288 i = sizeof(struct buffer_head *) * groups_per_page; 1289 bh = kzalloc(i, gfp); 1290 if (bh == NULL) 1291 return -ENOMEM; 1292 } else 1293 bh = &bhs; 1294 1295 first_group = page->index * blocks_per_page / 2; 1296 1297 /* read all groups the page covers into the cache */ 1298 for (i = 0, group = first_group; i < groups_per_page; i++, group++) { 1299 if (group >= ngroups) 1300 break; 1301 1302 grinfo = ext4_get_group_info(sb, group); 1303 if (!grinfo) 1304 continue; 1305 /* 1306 * If page is uptodate then we came here after online resize 1307 * which added some new uninitialized group info structs, so 1308 * we must skip all initialized uptodate buddies on the page, 1309 * which may be currently in use by an allocating task. 1310 */ 1311 if (PageUptodate(page) && !EXT4_MB_GRP_NEED_INIT(grinfo)) { 1312 bh[i] = NULL; 1313 continue; 1314 } 1315 bh[i] = ext4_read_block_bitmap_nowait(sb, group, false); 1316 if (IS_ERR(bh[i])) { 1317 err = PTR_ERR(bh[i]); 1318 bh[i] = NULL; 1319 goto out; 1320 } 1321 mb_debug(sb, "read bitmap for group %u\n", group); 1322 } 1323 1324 /* wait for I/O completion */ 1325 for (i = 0, group = first_group; i < groups_per_page; i++, group++) { 1326 int err2; 1327 1328 if (!bh[i]) 1329 continue; 1330 err2 = ext4_wait_block_bitmap(sb, group, bh[i]); 1331 if (!err) 1332 err = err2; 1333 } 1334 1335 first_block = page->index * blocks_per_page; 1336 for (i = 0; i < blocks_per_page; i++) { 1337 group = (first_block + i) >> 1; 1338 if (group >= ngroups) 1339 break; 1340 1341 if (!bh[group - first_group]) 1342 /* skip initialized uptodate buddy */ 1343 continue; 1344 1345 if (!buffer_verified(bh[group - first_group])) 1346 /* Skip faulty bitmaps */ 1347 continue; 1348 err = 0; 1349 1350 /* 1351 * data carry information regarding this 1352 * particular group in the format specified 1353 * above 1354 * 1355 */ 1356 data = page_address(page) + (i * blocksize); 1357 bitmap = bh[group - first_group]->b_data; 1358 1359 /* 1360 * We place the buddy block and bitmap block 1361 * close together 1362 */ 1363 grinfo = ext4_get_group_info(sb, group); 1364 if (!grinfo) { 1365 err = -EFSCORRUPTED; 1366 goto out; 1367 } 1368 if ((first_block + i) & 1) { 1369 /* this is block of buddy */ 1370 BUG_ON(incore == NULL); 1371 mb_debug(sb, "put buddy for group %u in page %lu/%x\n", 1372 group, page->index, i * blocksize); 1373 trace_ext4_mb_buddy_bitmap_load(sb, group); 1374 grinfo->bb_fragments = 0; 1375 memset(grinfo->bb_counters, 0, 1376 sizeof(*grinfo->bb_counters) * 1377 (MB_NUM_ORDERS(sb))); 1378 /* 1379 * incore got set to the group block bitmap below 1380 */ 1381 ext4_lock_group(sb, group); 1382 /* init the buddy */ 1383 memset(data, 0xff, blocksize); 1384 ext4_mb_generate_buddy(sb, data, incore, group, grinfo); 1385 ext4_unlock_group(sb, group); 1386 incore = NULL; 1387 } else { 1388 /* this is block of bitmap */ 1389 BUG_ON(incore != NULL); 1390 mb_debug(sb, "put bitmap for group %u in page %lu/%x\n", 1391 group, page->index, i * blocksize); 1392 trace_ext4_mb_bitmap_load(sb, group); 1393 1394 /* see comments in ext4_mb_put_pa() */ 1395 ext4_lock_group(sb, group); 1396 memcpy(data, bitmap, blocksize); 1397 1398 /* mark all preallocated blks used in in-core bitmap */ 1399 ext4_mb_generate_from_pa(sb, data, group); 1400 WARN_ON_ONCE(!RB_EMPTY_ROOT(&grinfo->bb_free_root)); 1401 ext4_unlock_group(sb, group); 1402 1403 /* set incore so that the buddy information can be 1404 * generated using this 1405 */ 1406 incore = data; 1407 } 1408 } 1409 SetPageUptodate(page); 1410 1411 out: 1412 if (bh) { 1413 for (i = 0; i < groups_per_page; i++) 1414 brelse(bh[i]); 1415 if (bh != &bhs) 1416 kfree(bh); 1417 } 1418 return err; 1419 } 1420 1421 /* 1422 * Lock the buddy and bitmap pages. This make sure other parallel init_group 1423 * on the same buddy page doesn't happen whild holding the buddy page lock. 1424 * Return locked buddy and bitmap pages on e4b struct. If buddy and bitmap 1425 * are on the same page e4b->bd_buddy_page is NULL and return value is 0. 1426 */ 1427 static int ext4_mb_get_buddy_page_lock(struct super_block *sb, 1428 ext4_group_t group, struct ext4_buddy *e4b, gfp_t gfp) 1429 { 1430 struct inode *inode = EXT4_SB(sb)->s_buddy_cache; 1431 int block, pnum, poff; 1432 int blocks_per_page; 1433 struct page *page; 1434 1435 e4b->bd_buddy_page = NULL; 1436 e4b->bd_bitmap_page = NULL; 1437 1438 blocks_per_page = PAGE_SIZE / sb->s_blocksize; 1439 /* 1440 * the buddy cache inode stores the block bitmap 1441 * and buddy information in consecutive blocks. 1442 * So for each group we need two blocks. 1443 */ 1444 block = group * 2; 1445 pnum = block / blocks_per_page; 1446 poff = block % blocks_per_page; 1447 page = find_or_create_page(inode->i_mapping, pnum, gfp); 1448 if (!page) 1449 return -ENOMEM; 1450 BUG_ON(page->mapping != inode->i_mapping); 1451 e4b->bd_bitmap_page = page; 1452 e4b->bd_bitmap = page_address(page) + (poff * sb->s_blocksize); 1453 1454 if (blocks_per_page >= 2) { 1455 /* buddy and bitmap are on the same page */ 1456 return 0; 1457 } 1458 1459 block++; 1460 pnum = block / blocks_per_page; 1461 page = find_or_create_page(inode->i_mapping, pnum, gfp); 1462 if (!page) 1463 return -ENOMEM; 1464 BUG_ON(page->mapping != inode->i_mapping); 1465 e4b->bd_buddy_page = page; 1466 return 0; 1467 } 1468 1469 static void ext4_mb_put_buddy_page_lock(struct ext4_buddy *e4b) 1470 { 1471 if (e4b->bd_bitmap_page) { 1472 unlock_page(e4b->bd_bitmap_page); 1473 put_page(e4b->bd_bitmap_page); 1474 } 1475 if (e4b->bd_buddy_page) { 1476 unlock_page(e4b->bd_buddy_page); 1477 put_page(e4b->bd_buddy_page); 1478 } 1479 } 1480 1481 /* 1482 * Locking note: This routine calls ext4_mb_init_cache(), which takes the 1483 * block group lock of all groups for this page; do not hold the BG lock when 1484 * calling this routine! 1485 */ 1486 static noinline_for_stack 1487 int ext4_mb_init_group(struct super_block *sb, ext4_group_t group, gfp_t gfp) 1488 { 1489 1490 struct ext4_group_info *this_grp; 1491 struct ext4_buddy e4b; 1492 struct page *page; 1493 int ret = 0; 1494 1495 might_sleep(); 1496 mb_debug(sb, "init group %u\n", group); 1497 this_grp = ext4_get_group_info(sb, group); 1498 if (!this_grp) 1499 return -EFSCORRUPTED; 1500 1501 /* 1502 * This ensures that we don't reinit the buddy cache 1503 * page which map to the group from which we are already 1504 * allocating. If we are looking at the buddy cache we would 1505 * have taken a reference using ext4_mb_load_buddy and that 1506 * would have pinned buddy page to page cache. 1507 * The call to ext4_mb_get_buddy_page_lock will mark the 1508 * page accessed. 1509 */ 1510 ret = ext4_mb_get_buddy_page_lock(sb, group, &e4b, gfp); 1511 if (ret || !EXT4_MB_GRP_NEED_INIT(this_grp)) { 1512 /* 1513 * somebody initialized the group 1514 * return without doing anything 1515 */ 1516 goto err; 1517 } 1518 1519 page = e4b.bd_bitmap_page; 1520 ret = ext4_mb_init_cache(page, NULL, gfp); 1521 if (ret) 1522 goto err; 1523 if (!PageUptodate(page)) { 1524 ret = -EIO; 1525 goto err; 1526 } 1527 1528 if (e4b.bd_buddy_page == NULL) { 1529 /* 1530 * If both the bitmap and buddy are in 1531 * the same page we don't need to force 1532 * init the buddy 1533 */ 1534 ret = 0; 1535 goto err; 1536 } 1537 /* init buddy cache */ 1538 page = e4b.bd_buddy_page; 1539 ret = ext4_mb_init_cache(page, e4b.bd_bitmap, gfp); 1540 if (ret) 1541 goto err; 1542 if (!PageUptodate(page)) { 1543 ret = -EIO; 1544 goto err; 1545 } 1546 err: 1547 ext4_mb_put_buddy_page_lock(&e4b); 1548 return ret; 1549 } 1550 1551 /* 1552 * Locking note: This routine calls ext4_mb_init_cache(), which takes the 1553 * block group lock of all groups for this page; do not hold the BG lock when 1554 * calling this routine! 1555 */ 1556 static noinline_for_stack int 1557 ext4_mb_load_buddy_gfp(struct super_block *sb, ext4_group_t group, 1558 struct ext4_buddy *e4b, gfp_t gfp) 1559 { 1560 int blocks_per_page; 1561 int block; 1562 int pnum; 1563 int poff; 1564 struct page *page; 1565 int ret; 1566 struct ext4_group_info *grp; 1567 struct ext4_sb_info *sbi = EXT4_SB(sb); 1568 struct inode *inode = sbi->s_buddy_cache; 1569 1570 might_sleep(); 1571 mb_debug(sb, "load group %u\n", group); 1572 1573 blocks_per_page = PAGE_SIZE / sb->s_blocksize; 1574 grp = ext4_get_group_info(sb, group); 1575 if (!grp) 1576 return -EFSCORRUPTED; 1577 1578 e4b->bd_blkbits = sb->s_blocksize_bits; 1579 e4b->bd_info = grp; 1580 e4b->bd_sb = sb; 1581 e4b->bd_group = group; 1582 e4b->bd_buddy_page = NULL; 1583 e4b->bd_bitmap_page = NULL; 1584 1585 if (unlikely(EXT4_MB_GRP_NEED_INIT(grp))) { 1586 /* 1587 * we need full data about the group 1588 * to make a good selection 1589 */ 1590 ret = ext4_mb_init_group(sb, group, gfp); 1591 if (ret) 1592 return ret; 1593 } 1594 1595 /* 1596 * the buddy cache inode stores the block bitmap 1597 * and buddy information in consecutive blocks. 1598 * So for each group we need two blocks. 1599 */ 1600 block = group * 2; 1601 pnum = block / blocks_per_page; 1602 poff = block % blocks_per_page; 1603 1604 /* we could use find_or_create_page(), but it locks page 1605 * what we'd like to avoid in fast path ... */ 1606 page = find_get_page_flags(inode->i_mapping, pnum, FGP_ACCESSED); 1607 if (page == NULL || !PageUptodate(page)) { 1608 if (page) 1609 /* 1610 * drop the page reference and try 1611 * to get the page with lock. If we 1612 * are not uptodate that implies 1613 * somebody just created the page but 1614 * is yet to initialize the same. So 1615 * wait for it to initialize. 1616 */ 1617 put_page(page); 1618 page = find_or_create_page(inode->i_mapping, pnum, gfp); 1619 if (page) { 1620 if (WARN_RATELIMIT(page->mapping != inode->i_mapping, 1621 "ext4: bitmap's paging->mapping != inode->i_mapping\n")) { 1622 /* should never happen */ 1623 unlock_page(page); 1624 ret = -EINVAL; 1625 goto err; 1626 } 1627 if (!PageUptodate(page)) { 1628 ret = ext4_mb_init_cache(page, NULL, gfp); 1629 if (ret) { 1630 unlock_page(page); 1631 goto err; 1632 } 1633 mb_cmp_bitmaps(e4b, page_address(page) + 1634 (poff * sb->s_blocksize)); 1635 } 1636 unlock_page(page); 1637 } 1638 } 1639 if (page == NULL) { 1640 ret = -ENOMEM; 1641 goto err; 1642 } 1643 if (!PageUptodate(page)) { 1644 ret = -EIO; 1645 goto err; 1646 } 1647 1648 /* Pages marked accessed already */ 1649 e4b->bd_bitmap_page = page; 1650 e4b->bd_bitmap = page_address(page) + (poff * sb->s_blocksize); 1651 1652 block++; 1653 pnum = block / blocks_per_page; 1654 poff = block % blocks_per_page; 1655 1656 page = find_get_page_flags(inode->i_mapping, pnum, FGP_ACCESSED); 1657 if (page == NULL || !PageUptodate(page)) { 1658 if (page) 1659 put_page(page); 1660 page = find_or_create_page(inode->i_mapping, pnum, gfp); 1661 if (page) { 1662 if (WARN_RATELIMIT(page->mapping != inode->i_mapping, 1663 "ext4: buddy bitmap's page->mapping != inode->i_mapping\n")) { 1664 /* should never happen */ 1665 unlock_page(page); 1666 ret = -EINVAL; 1667 goto err; 1668 } 1669 if (!PageUptodate(page)) { 1670 ret = ext4_mb_init_cache(page, e4b->bd_bitmap, 1671 gfp); 1672 if (ret) { 1673 unlock_page(page); 1674 goto err; 1675 } 1676 } 1677 unlock_page(page); 1678 } 1679 } 1680 if (page == NULL) { 1681 ret = -ENOMEM; 1682 goto err; 1683 } 1684 if (!PageUptodate(page)) { 1685 ret = -EIO; 1686 goto err; 1687 } 1688 1689 /* Pages marked accessed already */ 1690 e4b->bd_buddy_page = page; 1691 e4b->bd_buddy = page_address(page) + (poff * sb->s_blocksize); 1692 1693 return 0; 1694 1695 err: 1696 if (page) 1697 put_page(page); 1698 if (e4b->bd_bitmap_page) 1699 put_page(e4b->bd_bitmap_page); 1700 1701 e4b->bd_buddy = NULL; 1702 e4b->bd_bitmap = NULL; 1703 return ret; 1704 } 1705 1706 static int ext4_mb_load_buddy(struct super_block *sb, ext4_group_t group, 1707 struct ext4_buddy *e4b) 1708 { 1709 return ext4_mb_load_buddy_gfp(sb, group, e4b, GFP_NOFS); 1710 } 1711 1712 static void ext4_mb_unload_buddy(struct ext4_buddy *e4b) 1713 { 1714 if (e4b->bd_bitmap_page) 1715 put_page(e4b->bd_bitmap_page); 1716 if (e4b->bd_buddy_page) 1717 put_page(e4b->bd_buddy_page); 1718 } 1719 1720 1721 static int mb_find_order_for_block(struct ext4_buddy *e4b, int block) 1722 { 1723 int order = 1, max; 1724 void *bb; 1725 1726 BUG_ON(e4b->bd_bitmap == e4b->bd_buddy); 1727 BUG_ON(block >= (1 << (e4b->bd_blkbits + 3))); 1728 1729 while (order <= e4b->bd_blkbits + 1) { 1730 bb = mb_find_buddy(e4b, order, &max); 1731 if (!mb_test_bit(block >> order, bb)) { 1732 /* this block is part of buddy of order 'order' */ 1733 return order; 1734 } 1735 order++; 1736 } 1737 return 0; 1738 } 1739 1740 static void mb_clear_bits(void *bm, int cur, int len) 1741 { 1742 __u32 *addr; 1743 1744 len = cur + len; 1745 while (cur < len) { 1746 if ((cur & 31) == 0 && (len - cur) >= 32) { 1747 /* fast path: clear whole word at once */ 1748 addr = bm + (cur >> 3); 1749 *addr = 0; 1750 cur += 32; 1751 continue; 1752 } 1753 mb_clear_bit(cur, bm); 1754 cur++; 1755 } 1756 } 1757 1758 /* clear bits in given range 1759 * will return first found zero bit if any, -1 otherwise 1760 */ 1761 static int mb_test_and_clear_bits(void *bm, int cur, int len) 1762 { 1763 __u32 *addr; 1764 int zero_bit = -1; 1765 1766 len = cur + len; 1767 while (cur < len) { 1768 if ((cur & 31) == 0 && (len - cur) >= 32) { 1769 /* fast path: clear whole word at once */ 1770 addr = bm + (cur >> 3); 1771 if (*addr != (__u32)(-1) && zero_bit == -1) 1772 zero_bit = cur + mb_find_next_zero_bit(addr, 32, 0); 1773 *addr = 0; 1774 cur += 32; 1775 continue; 1776 } 1777 if (!mb_test_and_clear_bit(cur, bm) && zero_bit == -1) 1778 zero_bit = cur; 1779 cur++; 1780 } 1781 1782 return zero_bit; 1783 } 1784 1785 void mb_set_bits(void *bm, int cur, int len) 1786 { 1787 __u32 *addr; 1788 1789 len = cur + len; 1790 while (cur < len) { 1791 if ((cur & 31) == 0 && (len - cur) >= 32) { 1792 /* fast path: set whole word at once */ 1793 addr = bm + (cur >> 3); 1794 *addr = 0xffffffff; 1795 cur += 32; 1796 continue; 1797 } 1798 mb_set_bit(cur, bm); 1799 cur++; 1800 } 1801 } 1802 1803 static inline int mb_buddy_adjust_border(int* bit, void* bitmap, int side) 1804 { 1805 if (mb_test_bit(*bit + side, bitmap)) { 1806 mb_clear_bit(*bit, bitmap); 1807 (*bit) -= side; 1808 return 1; 1809 } 1810 else { 1811 (*bit) += side; 1812 mb_set_bit(*bit, bitmap); 1813 return -1; 1814 } 1815 } 1816 1817 static void mb_buddy_mark_free(struct ext4_buddy *e4b, int first, int last) 1818 { 1819 int max; 1820 int order = 1; 1821 void *buddy = mb_find_buddy(e4b, order, &max); 1822 1823 while (buddy) { 1824 void *buddy2; 1825 1826 /* Bits in range [first; last] are known to be set since 1827 * corresponding blocks were allocated. Bits in range 1828 * (first; last) will stay set because they form buddies on 1829 * upper layer. We just deal with borders if they don't 1830 * align with upper layer and then go up. 1831 * Releasing entire group is all about clearing 1832 * single bit of highest order buddy. 1833 */ 1834 1835 /* Example: 1836 * --------------------------------- 1837 * | 1 | 1 | 1 | 1 | 1838 * --------------------------------- 1839 * | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1840 * --------------------------------- 1841 * 0 1 2 3 4 5 6 7 1842 * \_____________________/ 1843 * 1844 * Neither [1] nor [6] is aligned to above layer. 1845 * Left neighbour [0] is free, so mark it busy, 1846 * decrease bb_counters and extend range to 1847 * [0; 6] 1848 * Right neighbour [7] is busy. It can't be coaleasced with [6], so 1849 * mark [6] free, increase bb_counters and shrink range to 1850 * [0; 5]. 1851 * Then shift range to [0; 2], go up and do the same. 1852 */ 1853 1854 1855 if (first & 1) 1856 e4b->bd_info->bb_counters[order] += mb_buddy_adjust_border(&first, buddy, -1); 1857 if (!(last & 1)) 1858 e4b->bd_info->bb_counters[order] += mb_buddy_adjust_border(&last, buddy, 1); 1859 if (first > last) 1860 break; 1861 order++; 1862 1863 buddy2 = mb_find_buddy(e4b, order, &max); 1864 if (!buddy2) { 1865 mb_clear_bits(buddy, first, last - first + 1); 1866 e4b->bd_info->bb_counters[order - 1] += last - first + 1; 1867 break; 1868 } 1869 first >>= 1; 1870 last >>= 1; 1871 buddy = buddy2; 1872 } 1873 } 1874 1875 static void mb_free_blocks(struct inode *inode, struct ext4_buddy *e4b, 1876 int first, int count) 1877 { 1878 int left_is_free = 0; 1879 int right_is_free = 0; 1880 int block; 1881 int last = first + count - 1; 1882 struct super_block *sb = e4b->bd_sb; 1883 1884 if (WARN_ON(count == 0)) 1885 return; 1886 BUG_ON(last >= (sb->s_blocksize << 3)); 1887 assert_spin_locked(ext4_group_lock_ptr(sb, e4b->bd_group)); 1888 /* Don't bother if the block group is corrupt. */ 1889 if (unlikely(EXT4_MB_GRP_BBITMAP_CORRUPT(e4b->bd_info))) 1890 return; 1891 1892 mb_check_buddy(e4b); 1893 mb_free_blocks_double(inode, e4b, first, count); 1894 1895 this_cpu_inc(discard_pa_seq); 1896 e4b->bd_info->bb_free += count; 1897 if (first < e4b->bd_info->bb_first_free) 1898 e4b->bd_info->bb_first_free = first; 1899 1900 /* access memory sequentially: check left neighbour, 1901 * clear range and then check right neighbour 1902 */ 1903 if (first != 0) 1904 left_is_free = !mb_test_bit(first - 1, e4b->bd_bitmap); 1905 block = mb_test_and_clear_bits(e4b->bd_bitmap, first, count); 1906 if (last + 1 < EXT4_SB(sb)->s_mb_maxs[0]) 1907 right_is_free = !mb_test_bit(last + 1, e4b->bd_bitmap); 1908 1909 if (unlikely(block != -1)) { 1910 struct ext4_sb_info *sbi = EXT4_SB(sb); 1911 ext4_fsblk_t blocknr; 1912 1913 blocknr = ext4_group_first_block_no(sb, e4b->bd_group); 1914 blocknr += EXT4_C2B(sbi, block); 1915 if (!(sbi->s_mount_state & EXT4_FC_REPLAY)) { 1916 ext4_grp_locked_error(sb, e4b->bd_group, 1917 inode ? inode->i_ino : 0, 1918 blocknr, 1919 "freeing already freed block (bit %u); block bitmap corrupt.", 1920 block); 1921 ext4_mark_group_bitmap_corrupted( 1922 sb, e4b->bd_group, 1923 EXT4_GROUP_INFO_BBITMAP_CORRUPT); 1924 } 1925 goto done; 1926 } 1927 1928 /* let's maintain fragments counter */ 1929 if (left_is_free && right_is_free) 1930 e4b->bd_info->bb_fragments--; 1931 else if (!left_is_free && !right_is_free) 1932 e4b->bd_info->bb_fragments++; 1933 1934 /* buddy[0] == bd_bitmap is a special case, so handle 1935 * it right away and let mb_buddy_mark_free stay free of 1936 * zero order checks. 1937 * Check if neighbours are to be coaleasced, 1938 * adjust bitmap bb_counters and borders appropriately. 1939 */ 1940 if (first & 1) { 1941 first += !left_is_free; 1942 e4b->bd_info->bb_counters[0] += left_is_free ? -1 : 1; 1943 } 1944 if (!(last & 1)) { 1945 last -= !right_is_free; 1946 e4b->bd_info->bb_counters[0] += right_is_free ? -1 : 1; 1947 } 1948 1949 if (first <= last) 1950 mb_buddy_mark_free(e4b, first >> 1, last >> 1); 1951 1952 done: 1953 mb_set_largest_free_order(sb, e4b->bd_info); 1954 mb_update_avg_fragment_size(sb, e4b->bd_info); 1955 mb_check_buddy(e4b); 1956 } 1957 1958 static int mb_find_extent(struct ext4_buddy *e4b, int block, 1959 int needed, struct ext4_free_extent *ex) 1960 { 1961 int next = block; 1962 int max, order; 1963 void *buddy; 1964 1965 assert_spin_locked(ext4_group_lock_ptr(e4b->bd_sb, e4b->bd_group)); 1966 BUG_ON(ex == NULL); 1967 1968 buddy = mb_find_buddy(e4b, 0, &max); 1969 BUG_ON(buddy == NULL); 1970 BUG_ON(block >= max); 1971 if (mb_test_bit(block, buddy)) { 1972 ex->fe_len = 0; 1973 ex->fe_start = 0; 1974 ex->fe_group = 0; 1975 return 0; 1976 } 1977 1978 /* find actual order */ 1979 order = mb_find_order_for_block(e4b, block); 1980 block = block >> order; 1981 1982 ex->fe_len = 1 << order; 1983 ex->fe_start = block << order; 1984 ex->fe_group = e4b->bd_group; 1985 1986 /* calc difference from given start */ 1987 next = next - ex->fe_start; 1988 ex->fe_len -= next; 1989 ex->fe_start += next; 1990 1991 while (needed > ex->fe_len && 1992 mb_find_buddy(e4b, order, &max)) { 1993 1994 if (block + 1 >= max) 1995 break; 1996 1997 next = (block + 1) * (1 << order); 1998 if (mb_test_bit(next, e4b->bd_bitmap)) 1999 break; 2000 2001 order = mb_find_order_for_block(e4b, next); 2002 2003 block = next >> order; 2004 ex->fe_len += 1 << order; 2005 } 2006 2007 if (ex->fe_start + ex->fe_len > EXT4_CLUSTERS_PER_GROUP(e4b->bd_sb)) { 2008 /* Should never happen! (but apparently sometimes does?!?) */ 2009 WARN_ON(1); 2010 ext4_grp_locked_error(e4b->bd_sb, e4b->bd_group, 0, 0, 2011 "corruption or bug in mb_find_extent " 2012 "block=%d, order=%d needed=%d ex=%u/%d/%d@%u", 2013 block, order, needed, ex->fe_group, ex->fe_start, 2014 ex->fe_len, ex->fe_logical); 2015 ex->fe_len = 0; 2016 ex->fe_start = 0; 2017 ex->fe_group = 0; 2018 } 2019 return ex->fe_len; 2020 } 2021 2022 static int mb_mark_used(struct ext4_buddy *e4b, struct ext4_free_extent *ex) 2023 { 2024 int ord; 2025 int mlen = 0; 2026 int max = 0; 2027 int cur; 2028 int start = ex->fe_start; 2029 int len = ex->fe_len; 2030 unsigned ret = 0; 2031 int len0 = len; 2032 void *buddy; 2033 bool split = false; 2034 2035 BUG_ON(start + len > (e4b->bd_sb->s_blocksize << 3)); 2036 BUG_ON(e4b->bd_group != ex->fe_group); 2037 assert_spin_locked(ext4_group_lock_ptr(e4b->bd_sb, e4b->bd_group)); 2038 mb_check_buddy(e4b); 2039 mb_mark_used_double(e4b, start, len); 2040 2041 this_cpu_inc(discard_pa_seq); 2042 e4b->bd_info->bb_free -= len; 2043 if (e4b->bd_info->bb_first_free == start) 2044 e4b->bd_info->bb_first_free += len; 2045 2046 /* let's maintain fragments counter */ 2047 if (start != 0) 2048 mlen = !mb_test_bit(start - 1, e4b->bd_bitmap); 2049 if (start + len < EXT4_SB(e4b->bd_sb)->s_mb_maxs[0]) 2050 max = !mb_test_bit(start + len, e4b->bd_bitmap); 2051 if (mlen && max) 2052 e4b->bd_info->bb_fragments++; 2053 else if (!mlen && !max) 2054 e4b->bd_info->bb_fragments--; 2055 2056 /* let's maintain buddy itself */ 2057 while (len) { 2058 if (!split) 2059 ord = mb_find_order_for_block(e4b, start); 2060 2061 if (((start >> ord) << ord) == start && len >= (1 << ord)) { 2062 /* the whole chunk may be allocated at once! */ 2063 mlen = 1 << ord; 2064 if (!split) 2065 buddy = mb_find_buddy(e4b, ord, &max); 2066 else 2067 split = false; 2068 BUG_ON((start >> ord) >= max); 2069 mb_set_bit(start >> ord, buddy); 2070 e4b->bd_info->bb_counters[ord]--; 2071 start += mlen; 2072 len -= mlen; 2073 BUG_ON(len < 0); 2074 continue; 2075 } 2076 2077 /* store for history */ 2078 if (ret == 0) 2079 ret = len | (ord << 16); 2080 2081 /* we have to split large buddy */ 2082 BUG_ON(ord <= 0); 2083 buddy = mb_find_buddy(e4b, ord, &max); 2084 mb_set_bit(start >> ord, buddy); 2085 e4b->bd_info->bb_counters[ord]--; 2086 2087 ord--; 2088 cur = (start >> ord) & ~1U; 2089 buddy = mb_find_buddy(e4b, ord, &max); 2090 mb_clear_bit(cur, buddy); 2091 mb_clear_bit(cur + 1, buddy); 2092 e4b->bd_info->bb_counters[ord]++; 2093 e4b->bd_info->bb_counters[ord]++; 2094 split = true; 2095 } 2096 mb_set_largest_free_order(e4b->bd_sb, e4b->bd_info); 2097 2098 mb_update_avg_fragment_size(e4b->bd_sb, e4b->bd_info); 2099 mb_set_bits(e4b->bd_bitmap, ex->fe_start, len0); 2100 mb_check_buddy(e4b); 2101 2102 return ret; 2103 } 2104 2105 /* 2106 * Must be called under group lock! 2107 */ 2108 static void ext4_mb_use_best_found(struct ext4_allocation_context *ac, 2109 struct ext4_buddy *e4b) 2110 { 2111 struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb); 2112 int ret; 2113 2114 BUG_ON(ac->ac_b_ex.fe_group != e4b->bd_group); 2115 BUG_ON(ac->ac_status == AC_STATUS_FOUND); 2116 2117 ac->ac_b_ex.fe_len = min(ac->ac_b_ex.fe_len, ac->ac_g_ex.fe_len); 2118 ac->ac_b_ex.fe_logical = ac->ac_g_ex.fe_logical; 2119 ret = mb_mark_used(e4b, &ac->ac_b_ex); 2120 2121 /* preallocation can change ac_b_ex, thus we store actually 2122 * allocated blocks for history */ 2123 ac->ac_f_ex = ac->ac_b_ex; 2124 2125 ac->ac_status = AC_STATUS_FOUND; 2126 ac->ac_tail = ret & 0xffff; 2127 ac->ac_buddy = ret >> 16; 2128 2129 /* 2130 * take the page reference. We want the page to be pinned 2131 * so that we don't get a ext4_mb_init_cache_call for this 2132 * group until we update the bitmap. That would mean we 2133 * double allocate blocks. The reference is dropped 2134 * in ext4_mb_release_context 2135 */ 2136 ac->ac_bitmap_page = e4b->bd_bitmap_page; 2137 get_page(ac->ac_bitmap_page); 2138 ac->ac_buddy_page = e4b->bd_buddy_page; 2139 get_page(ac->ac_buddy_page); 2140 /* store last allocated for subsequent stream allocation */ 2141 if (ac->ac_flags & EXT4_MB_STREAM_ALLOC) { 2142 spin_lock(&sbi->s_md_lock); 2143 sbi->s_mb_last_group = ac->ac_f_ex.fe_group; 2144 sbi->s_mb_last_start = ac->ac_f_ex.fe_start; 2145 spin_unlock(&sbi->s_md_lock); 2146 } 2147 /* 2148 * As we've just preallocated more space than 2149 * user requested originally, we store allocated 2150 * space in a special descriptor. 2151 */ 2152 if (ac->ac_o_ex.fe_len < ac->ac_b_ex.fe_len) 2153 ext4_mb_new_preallocation(ac); 2154 2155 } 2156 2157 static void ext4_mb_check_limits(struct ext4_allocation_context *ac, 2158 struct ext4_buddy *e4b, 2159 int finish_group) 2160 { 2161 struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb); 2162 struct ext4_free_extent *bex = &ac->ac_b_ex; 2163 struct ext4_free_extent *gex = &ac->ac_g_ex; 2164 2165 if (ac->ac_status == AC_STATUS_FOUND) 2166 return; 2167 /* 2168 * We don't want to scan for a whole year 2169 */ 2170 if (ac->ac_found > sbi->s_mb_max_to_scan && 2171 !(ac->ac_flags & EXT4_MB_HINT_FIRST)) { 2172 ac->ac_status = AC_STATUS_BREAK; 2173 return; 2174 } 2175 2176 /* 2177 * Haven't found good chunk so far, let's continue 2178 */ 2179 if (bex->fe_len < gex->fe_len) 2180 return; 2181 2182 if (finish_group || ac->ac_found > sbi->s_mb_min_to_scan) 2183 ext4_mb_use_best_found(ac, e4b); 2184 } 2185 2186 /* 2187 * The routine checks whether found extent is good enough. If it is, 2188 * then the extent gets marked used and flag is set to the context 2189 * to stop scanning. Otherwise, the extent is compared with the 2190 * previous found extent and if new one is better, then it's stored 2191 * in the context. Later, the best found extent will be used, if 2192 * mballoc can't find good enough extent. 2193 * 2194 * The algorithm used is roughly as follows: 2195 * 2196 * * If free extent found is exactly as big as goal, then 2197 * stop the scan and use it immediately 2198 * 2199 * * If free extent found is smaller than goal, then keep retrying 2200 * upto a max of sbi->s_mb_max_to_scan times (default 200). After 2201 * that stop scanning and use whatever we have. 2202 * 2203 * * If free extent found is bigger than goal, then keep retrying 2204 * upto a max of sbi->s_mb_min_to_scan times (default 10) before 2205 * stopping the scan and using the extent. 2206 * 2207 * 2208 * FIXME: real allocation policy is to be designed yet! 2209 */ 2210 static void ext4_mb_measure_extent(struct ext4_allocation_context *ac, 2211 struct ext4_free_extent *ex, 2212 struct ext4_buddy *e4b) 2213 { 2214 struct ext4_free_extent *bex = &ac->ac_b_ex; 2215 struct ext4_free_extent *gex = &ac->ac_g_ex; 2216 2217 BUG_ON(ex->fe_len <= 0); 2218 BUG_ON(ex->fe_len > EXT4_CLUSTERS_PER_GROUP(ac->ac_sb)); 2219 BUG_ON(ex->fe_start >= EXT4_CLUSTERS_PER_GROUP(ac->ac_sb)); 2220 BUG_ON(ac->ac_status != AC_STATUS_CONTINUE); 2221 2222 ac->ac_found++; 2223 ac->ac_cX_found[ac->ac_criteria]++; 2224 2225 /* 2226 * The special case - take what you catch first 2227 */ 2228 if (unlikely(ac->ac_flags & EXT4_MB_HINT_FIRST)) { 2229 *bex = *ex; 2230 ext4_mb_use_best_found(ac, e4b); 2231 return; 2232 } 2233 2234 /* 2235 * Let's check whether the chuck is good enough 2236 */ 2237 if (ex->fe_len == gex->fe_len) { 2238 *bex = *ex; 2239 ext4_mb_use_best_found(ac, e4b); 2240 return; 2241 } 2242 2243 /* 2244 * If this is first found extent, just store it in the context 2245 */ 2246 if (bex->fe_len == 0) { 2247 *bex = *ex; 2248 return; 2249 } 2250 2251 /* 2252 * If new found extent is better, store it in the context 2253 */ 2254 if (bex->fe_len < gex->fe_len) { 2255 /* if the request isn't satisfied, any found extent 2256 * larger than previous best one is better */ 2257 if (ex->fe_len > bex->fe_len) 2258 *bex = *ex; 2259 } else if (ex->fe_len > gex->fe_len) { 2260 /* if the request is satisfied, then we try to find 2261 * an extent that still satisfy the request, but is 2262 * smaller than previous one */ 2263 if (ex->fe_len < bex->fe_len) 2264 *bex = *ex; 2265 } 2266 2267 ext4_mb_check_limits(ac, e4b, 0); 2268 } 2269 2270 static noinline_for_stack 2271 void ext4_mb_try_best_found(struct ext4_allocation_context *ac, 2272 struct ext4_buddy *e4b) 2273 { 2274 struct ext4_free_extent ex = ac->ac_b_ex; 2275 ext4_group_t group = ex.fe_group; 2276 int max; 2277 int err; 2278 2279 BUG_ON(ex.fe_len <= 0); 2280 err = ext4_mb_load_buddy(ac->ac_sb, group, e4b); 2281 if (err) 2282 return; 2283 2284 ext4_lock_group(ac->ac_sb, group); 2285 max = mb_find_extent(e4b, ex.fe_start, ex.fe_len, &ex); 2286 2287 if (max > 0) { 2288 ac->ac_b_ex = ex; 2289 ext4_mb_use_best_found(ac, e4b); 2290 } 2291 2292 ext4_unlock_group(ac->ac_sb, group); 2293 ext4_mb_unload_buddy(e4b); 2294 } 2295 2296 static noinline_for_stack 2297 int ext4_mb_find_by_goal(struct ext4_allocation_context *ac, 2298 struct ext4_buddy *e4b) 2299 { 2300 ext4_group_t group = ac->ac_g_ex.fe_group; 2301 int max; 2302 int err; 2303 struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb); 2304 struct ext4_group_info *grp = ext4_get_group_info(ac->ac_sb, group); 2305 struct ext4_free_extent ex; 2306 2307 if (!grp) 2308 return -EFSCORRUPTED; 2309 if (!(ac->ac_flags & (EXT4_MB_HINT_TRY_GOAL | EXT4_MB_HINT_GOAL_ONLY))) 2310 return 0; 2311 if (grp->bb_free == 0) 2312 return 0; 2313 2314 err = ext4_mb_load_buddy(ac->ac_sb, group, e4b); 2315 if (err) 2316 return err; 2317 2318 if (unlikely(EXT4_MB_GRP_BBITMAP_CORRUPT(e4b->bd_info))) { 2319 ext4_mb_unload_buddy(e4b); 2320 return 0; 2321 } 2322 2323 ext4_lock_group(ac->ac_sb, group); 2324 max = mb_find_extent(e4b, ac->ac_g_ex.fe_start, 2325 ac->ac_g_ex.fe_len, &ex); 2326 ex.fe_logical = 0xDEADFA11; /* debug value */ 2327 2328 if (max >= ac->ac_g_ex.fe_len && 2329 ac->ac_g_ex.fe_len == EXT4_B2C(sbi, sbi->s_stripe)) { 2330 ext4_fsblk_t start; 2331 2332 start = ext4_grp_offs_to_block(ac->ac_sb, &ex); 2333 /* use do_div to get remainder (would be 64-bit modulo) */ 2334 if (do_div(start, sbi->s_stripe) == 0) { 2335 ac->ac_found++; 2336 ac->ac_b_ex = ex; 2337 ext4_mb_use_best_found(ac, e4b); 2338 } 2339 } else if (max >= ac->ac_g_ex.fe_len) { 2340 BUG_ON(ex.fe_len <= 0); 2341 BUG_ON(ex.fe_group != ac->ac_g_ex.fe_group); 2342 BUG_ON(ex.fe_start != ac->ac_g_ex.fe_start); 2343 ac->ac_found++; 2344 ac->ac_b_ex = ex; 2345 ext4_mb_use_best_found(ac, e4b); 2346 } else if (max > 0 && (ac->ac_flags & EXT4_MB_HINT_MERGE)) { 2347 /* Sometimes, caller may want to merge even small 2348 * number of blocks to an existing extent */ 2349 BUG_ON(ex.fe_len <= 0); 2350 BUG_ON(ex.fe_group != ac->ac_g_ex.fe_group); 2351 BUG_ON(ex.fe_start != ac->ac_g_ex.fe_start); 2352 ac->ac_found++; 2353 ac->ac_b_ex = ex; 2354 ext4_mb_use_best_found(ac, e4b); 2355 } 2356 ext4_unlock_group(ac->ac_sb, group); 2357 ext4_mb_unload_buddy(e4b); 2358 2359 return 0; 2360 } 2361 2362 /* 2363 * The routine scans buddy structures (not bitmap!) from given order 2364 * to max order and tries to find big enough chunk to satisfy the req 2365 */ 2366 static noinline_for_stack 2367 void ext4_mb_simple_scan_group(struct ext4_allocation_context *ac, 2368 struct ext4_buddy *e4b) 2369 { 2370 struct super_block *sb = ac->ac_sb; 2371 struct ext4_group_info *grp = e4b->bd_info; 2372 void *buddy; 2373 int i; 2374 int k; 2375 int max; 2376 2377 BUG_ON(ac->ac_2order <= 0); 2378 for (i = ac->ac_2order; i < MB_NUM_ORDERS(sb); i++) { 2379 if (grp->bb_counters[i] == 0) 2380 continue; 2381 2382 buddy = mb_find_buddy(e4b, i, &max); 2383 if (WARN_RATELIMIT(buddy == NULL, 2384 "ext4: mb_simple_scan_group: mb_find_buddy failed, (%d)\n", i)) 2385 continue; 2386 2387 k = mb_find_next_zero_bit(buddy, max, 0); 2388 if (k >= max) { 2389 ext4_grp_locked_error(ac->ac_sb, e4b->bd_group, 0, 0, 2390 "%d free clusters of order %d. But found 0", 2391 grp->bb_counters[i], i); 2392 ext4_mark_group_bitmap_corrupted(ac->ac_sb, 2393 e4b->bd_group, 2394 EXT4_GROUP_INFO_BBITMAP_CORRUPT); 2395 break; 2396 } 2397 ac->ac_found++; 2398 ac->ac_cX_found[ac->ac_criteria]++; 2399 2400 ac->ac_b_ex.fe_len = 1 << i; 2401 ac->ac_b_ex.fe_start = k << i; 2402 ac->ac_b_ex.fe_group = e4b->bd_group; 2403 2404 ext4_mb_use_best_found(ac, e4b); 2405 2406 BUG_ON(ac->ac_f_ex.fe_len != ac->ac_g_ex.fe_len); 2407 2408 if (EXT4_SB(sb)->s_mb_stats) 2409 atomic_inc(&EXT4_SB(sb)->s_bal_2orders); 2410 2411 break; 2412 } 2413 } 2414 2415 /* 2416 * The routine scans the group and measures all found extents. 2417 * In order to optimize scanning, caller must pass number of 2418 * free blocks in the group, so the routine can know upper limit. 2419 */ 2420 static noinline_for_stack 2421 void ext4_mb_complex_scan_group(struct ext4_allocation_context *ac, 2422 struct ext4_buddy *e4b) 2423 { 2424 struct super_block *sb = ac->ac_sb; 2425 void *bitmap = e4b->bd_bitmap; 2426 struct ext4_free_extent ex; 2427 int i, j, freelen; 2428 int free; 2429 2430 free = e4b->bd_info->bb_free; 2431 if (WARN_ON(free <= 0)) 2432 return; 2433 2434 i = e4b->bd_info->bb_first_free; 2435 2436 while (free && ac->ac_status == AC_STATUS_CONTINUE) { 2437 i = mb_find_next_zero_bit(bitmap, 2438 EXT4_CLUSTERS_PER_GROUP(sb), i); 2439 if (i >= EXT4_CLUSTERS_PER_GROUP(sb)) { 2440 /* 2441 * IF we have corrupt bitmap, we won't find any 2442 * free blocks even though group info says we 2443 * have free blocks 2444 */ 2445 ext4_grp_locked_error(sb, e4b->bd_group, 0, 0, 2446 "%d free clusters as per " 2447 "group info. But bitmap says 0", 2448 free); 2449 ext4_mark_group_bitmap_corrupted(sb, e4b->bd_group, 2450 EXT4_GROUP_INFO_BBITMAP_CORRUPT); 2451 break; 2452 } 2453 2454 if (!ext4_mb_cr_expensive(ac->ac_criteria)) { 2455 /* 2456 * In CR_GOAL_LEN_FAST and CR_BEST_AVAIL_LEN, we are 2457 * sure that this group will have a large enough 2458 * continuous free extent, so skip over the smaller free 2459 * extents 2460 */ 2461 j = mb_find_next_bit(bitmap, 2462 EXT4_CLUSTERS_PER_GROUP(sb), i); 2463 freelen = j - i; 2464 2465 if (freelen < ac->ac_g_ex.fe_len) { 2466 i = j; 2467 free -= freelen; 2468 continue; 2469 } 2470 } 2471 2472 mb_find_extent(e4b, i, ac->ac_g_ex.fe_len, &ex); 2473 if (WARN_ON(ex.fe_len <= 0)) 2474 break; 2475 if (free < ex.fe_len) { 2476 ext4_grp_locked_error(sb, e4b->bd_group, 0, 0, 2477 "%d free clusters as per " 2478 "group info. But got %d blocks", 2479 free, ex.fe_len); 2480 ext4_mark_group_bitmap_corrupted(sb, e4b->bd_group, 2481 EXT4_GROUP_INFO_BBITMAP_CORRUPT); 2482 /* 2483 * The number of free blocks differs. This mostly 2484 * indicate that the bitmap is corrupt. So exit 2485 * without claiming the space. 2486 */ 2487 break; 2488 } 2489 ex.fe_logical = 0xDEADC0DE; /* debug value */ 2490 ext4_mb_measure_extent(ac, &ex, e4b); 2491 2492 i += ex.fe_len; 2493 free -= ex.fe_len; 2494 } 2495 2496 ext4_mb_check_limits(ac, e4b, 1); 2497 } 2498 2499 /* 2500 * This is a special case for storages like raid5 2501 * we try to find stripe-aligned chunks for stripe-size-multiple requests 2502 */ 2503 static noinline_for_stack 2504 void ext4_mb_scan_aligned(struct ext4_allocation_context *ac, 2505 struct ext4_buddy *e4b) 2506 { 2507 struct super_block *sb = ac->ac_sb; 2508 struct ext4_sb_info *sbi = EXT4_SB(sb); 2509 void *bitmap = e4b->bd_bitmap; 2510 struct ext4_free_extent ex; 2511 ext4_fsblk_t first_group_block; 2512 ext4_fsblk_t a; 2513 ext4_grpblk_t i, stripe; 2514 int max; 2515 2516 BUG_ON(sbi->s_stripe == 0); 2517 2518 /* find first stripe-aligned block in group */ 2519 first_group_block = ext4_group_first_block_no(sb, e4b->bd_group); 2520 2521 a = first_group_block + sbi->s_stripe - 1; 2522 do_div(a, sbi->s_stripe); 2523 i = (a * sbi->s_stripe) - first_group_block; 2524 2525 stripe = EXT4_B2C(sbi, sbi->s_stripe); 2526 i = EXT4_B2C(sbi, i); 2527 while (i < EXT4_CLUSTERS_PER_GROUP(sb)) { 2528 if (!mb_test_bit(i, bitmap)) { 2529 max = mb_find_extent(e4b, i, stripe, &ex); 2530 if (max >= stripe) { 2531 ac->ac_found++; 2532 ac->ac_cX_found[ac->ac_criteria]++; 2533 ex.fe_logical = 0xDEADF00D; /* debug value */ 2534 ac->ac_b_ex = ex; 2535 ext4_mb_use_best_found(ac, e4b); 2536 break; 2537 } 2538 } 2539 i += stripe; 2540 } 2541 } 2542 2543 /* 2544 * This is also called BEFORE we load the buddy bitmap. 2545 * Returns either 1 or 0 indicating that the group is either suitable 2546 * for the allocation or not. 2547 */ 2548 static bool ext4_mb_good_group(struct ext4_allocation_context *ac, 2549 ext4_group_t group, enum criteria cr) 2550 { 2551 ext4_grpblk_t free, fragments; 2552 int flex_size = ext4_flex_bg_size(EXT4_SB(ac->ac_sb)); 2553 struct ext4_group_info *grp = ext4_get_group_info(ac->ac_sb, group); 2554 2555 BUG_ON(cr < CR_POWER2_ALIGNED || cr >= EXT4_MB_NUM_CRS); 2556 2557 if (unlikely(!grp || EXT4_MB_GRP_BBITMAP_CORRUPT(grp))) 2558 return false; 2559 2560 free = grp->bb_free; 2561 if (free == 0) 2562 return false; 2563 2564 fragments = grp->bb_fragments; 2565 if (fragments == 0) 2566 return false; 2567 2568 switch (cr) { 2569 case CR_POWER2_ALIGNED: 2570 BUG_ON(ac->ac_2order == 0); 2571 2572 /* Avoid using the first bg of a flexgroup for data files */ 2573 if ((ac->ac_flags & EXT4_MB_HINT_DATA) && 2574 (flex_size >= EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME) && 2575 ((group % flex_size) == 0)) 2576 return false; 2577 2578 if (free < ac->ac_g_ex.fe_len) 2579 return false; 2580 2581 if (ac->ac_2order >= MB_NUM_ORDERS(ac->ac_sb)) 2582 return true; 2583 2584 if (grp->bb_largest_free_order < ac->ac_2order) 2585 return false; 2586 2587 return true; 2588 case CR_GOAL_LEN_FAST: 2589 case CR_BEST_AVAIL_LEN: 2590 if ((free / fragments) >= ac->ac_g_ex.fe_len) 2591 return true; 2592 break; 2593 case CR_GOAL_LEN_SLOW: 2594 if (free >= ac->ac_g_ex.fe_len) 2595 return true; 2596 break; 2597 case CR_ANY_FREE: 2598 return true; 2599 default: 2600 BUG(); 2601 } 2602 2603 return false; 2604 } 2605 2606 /* 2607 * This could return negative error code if something goes wrong 2608 * during ext4_mb_init_group(). This should not be called with 2609 * ext4_lock_group() held. 2610 * 2611 * Note: because we are conditionally operating with the group lock in 2612 * the EXT4_MB_STRICT_CHECK case, we need to fake out sparse in this 2613 * function using __acquire and __release. This means we need to be 2614 * super careful before messing with the error path handling via "goto 2615 * out"! 2616 */ 2617 static int ext4_mb_good_group_nolock(struct ext4_allocation_context *ac, 2618 ext4_group_t group, enum criteria cr) 2619 { 2620 struct ext4_group_info *grp = ext4_get_group_info(ac->ac_sb, group); 2621 struct super_block *sb = ac->ac_sb; 2622 struct ext4_sb_info *sbi = EXT4_SB(sb); 2623 bool should_lock = ac->ac_flags & EXT4_MB_STRICT_CHECK; 2624 ext4_grpblk_t free; 2625 int ret = 0; 2626 2627 if (!grp) 2628 return -EFSCORRUPTED; 2629 if (sbi->s_mb_stats) 2630 atomic64_inc(&sbi->s_bal_cX_groups_considered[ac->ac_criteria]); 2631 if (should_lock) { 2632 ext4_lock_group(sb, group); 2633 __release(ext4_group_lock_ptr(sb, group)); 2634 } 2635 free = grp->bb_free; 2636 if (free == 0) 2637 goto out; 2638 /* 2639 * In all criterias except CR_ANY_FREE we try to avoid groups that 2640 * can't possibly satisfy the full goal request due to insufficient 2641 * free blocks. 2642 */ 2643 if (cr < CR_ANY_FREE && free < ac->ac_g_ex.fe_len) 2644 goto out; 2645 if (unlikely(EXT4_MB_GRP_BBITMAP_CORRUPT(grp))) 2646 goto out; 2647 if (should_lock) { 2648 __acquire(ext4_group_lock_ptr(sb, group)); 2649 ext4_unlock_group(sb, group); 2650 } 2651 2652 /* We only do this if the grp has never been initialized */ 2653 if (unlikely(EXT4_MB_GRP_NEED_INIT(grp))) { 2654 struct ext4_group_desc *gdp = 2655 ext4_get_group_desc(sb, group, NULL); 2656 int ret; 2657 2658 /* 2659 * cr=CR_POWER2_ALIGNED/CR_GOAL_LEN_FAST is a very optimistic 2660 * search to find large good chunks almost for free. If buddy 2661 * data is not ready, then this optimization makes no sense. But 2662 * we never skip the first block group in a flex_bg, since this 2663 * gets used for metadata block allocation, and we want to make 2664 * sure we locate metadata blocks in the first block group in 2665 * the flex_bg if possible. 2666 */ 2667 if (!ext4_mb_cr_expensive(cr) && 2668 (!sbi->s_log_groups_per_flex || 2669 ((group & ((1 << sbi->s_log_groups_per_flex) - 1)) != 0)) && 2670 !(ext4_has_group_desc_csum(sb) && 2671 (gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)))) 2672 return 0; 2673 ret = ext4_mb_init_group(sb, group, GFP_NOFS); 2674 if (ret) 2675 return ret; 2676 } 2677 2678 if (should_lock) { 2679 ext4_lock_group(sb, group); 2680 __release(ext4_group_lock_ptr(sb, group)); 2681 } 2682 ret = ext4_mb_good_group(ac, group, cr); 2683 out: 2684 if (should_lock) { 2685 __acquire(ext4_group_lock_ptr(sb, group)); 2686 ext4_unlock_group(sb, group); 2687 } 2688 return ret; 2689 } 2690 2691 /* 2692 * Start prefetching @nr block bitmaps starting at @group. 2693 * Return the next group which needs to be prefetched. 2694 */ 2695 ext4_group_t ext4_mb_prefetch(struct super_block *sb, ext4_group_t group, 2696 unsigned int nr, int *cnt) 2697 { 2698 ext4_group_t ngroups = ext4_get_groups_count(sb); 2699 struct buffer_head *bh; 2700 struct blk_plug plug; 2701 2702 blk_start_plug(&plug); 2703 while (nr-- > 0) { 2704 struct ext4_group_desc *gdp = ext4_get_group_desc(sb, group, 2705 NULL); 2706 struct ext4_group_info *grp = ext4_get_group_info(sb, group); 2707 2708 /* 2709 * Prefetch block groups with free blocks; but don't 2710 * bother if it is marked uninitialized on disk, since 2711 * it won't require I/O to read. Also only try to 2712 * prefetch once, so we avoid getblk() call, which can 2713 * be expensive. 2714 */ 2715 if (gdp && grp && !EXT4_MB_GRP_TEST_AND_SET_READ(grp) && 2716 EXT4_MB_GRP_NEED_INIT(grp) && 2717 ext4_free_group_clusters(sb, gdp) > 0 ) { 2718 bh = ext4_read_block_bitmap_nowait(sb, group, true); 2719 if (bh && !IS_ERR(bh)) { 2720 if (!buffer_uptodate(bh) && cnt) 2721 (*cnt)++; 2722 brelse(bh); 2723 } 2724 } 2725 if (++group >= ngroups) 2726 group = 0; 2727 } 2728 blk_finish_plug(&plug); 2729 return group; 2730 } 2731 2732 /* 2733 * Prefetching reads the block bitmap into the buffer cache; but we 2734 * need to make sure that the buddy bitmap in the page cache has been 2735 * initialized. Note that ext4_mb_init_group() will block if the I/O 2736 * is not yet completed, or indeed if it was not initiated by 2737 * ext4_mb_prefetch did not start the I/O. 2738 * 2739 * TODO: We should actually kick off the buddy bitmap setup in a work 2740 * queue when the buffer I/O is completed, so that we don't block 2741 * waiting for the block allocation bitmap read to finish when 2742 * ext4_mb_prefetch_fini is called from ext4_mb_regular_allocator(). 2743 */ 2744 void ext4_mb_prefetch_fini(struct super_block *sb, ext4_group_t group, 2745 unsigned int nr) 2746 { 2747 struct ext4_group_desc *gdp; 2748 struct ext4_group_info *grp; 2749 2750 while (nr-- > 0) { 2751 if (!group) 2752 group = ext4_get_groups_count(sb); 2753 group--; 2754 gdp = ext4_get_group_desc(sb, group, NULL); 2755 grp = ext4_get_group_info(sb, group); 2756 2757 if (grp && gdp && EXT4_MB_GRP_NEED_INIT(grp) && 2758 ext4_free_group_clusters(sb, gdp) > 0) { 2759 if (ext4_mb_init_group(sb, group, GFP_NOFS)) 2760 break; 2761 } 2762 } 2763 } 2764 2765 static noinline_for_stack int 2766 ext4_mb_regular_allocator(struct ext4_allocation_context *ac) 2767 { 2768 ext4_group_t prefetch_grp = 0, ngroups, group, i; 2769 enum criteria new_cr, cr = CR_GOAL_LEN_FAST; 2770 int err = 0, first_err = 0; 2771 unsigned int nr = 0, prefetch_ios = 0; 2772 struct ext4_sb_info *sbi; 2773 struct super_block *sb; 2774 struct ext4_buddy e4b; 2775 int lost; 2776 2777 sb = ac->ac_sb; 2778 sbi = EXT4_SB(sb); 2779 ngroups = ext4_get_groups_count(sb); 2780 /* non-extent files are limited to low blocks/groups */ 2781 if (!(ext4_test_inode_flag(ac->ac_inode, EXT4_INODE_EXTENTS))) 2782 ngroups = sbi->s_blockfile_groups; 2783 2784 BUG_ON(ac->ac_status == AC_STATUS_FOUND); 2785 2786 /* first, try the goal */ 2787 err = ext4_mb_find_by_goal(ac, &e4b); 2788 if (err || ac->ac_status == AC_STATUS_FOUND) 2789 goto out; 2790 2791 if (unlikely(ac->ac_flags & EXT4_MB_HINT_GOAL_ONLY)) 2792 goto out; 2793 2794 /* 2795 * ac->ac_2order is set only if the fe_len is a power of 2 2796 * if ac->ac_2order is set we also set criteria to CR_POWER2_ALIGNED 2797 * so that we try exact allocation using buddy. 2798 */ 2799 i = fls(ac->ac_g_ex.fe_len); 2800 ac->ac_2order = 0; 2801 /* 2802 * We search using buddy data only if the order of the request 2803 * is greater than equal to the sbi_s_mb_order2_reqs 2804 * You can tune it via /sys/fs/ext4/<partition>/mb_order2_req 2805 * We also support searching for power-of-two requests only for 2806 * requests upto maximum buddy size we have constructed. 2807 */ 2808 if (i >= sbi->s_mb_order2_reqs && i <= MB_NUM_ORDERS(sb)) { 2809 if (is_power_of_2(ac->ac_g_ex.fe_len)) 2810 ac->ac_2order = array_index_nospec(i - 1, 2811 MB_NUM_ORDERS(sb)); 2812 } 2813 2814 /* if stream allocation is enabled, use global goal */ 2815 if (ac->ac_flags & EXT4_MB_STREAM_ALLOC) { 2816 /* TBD: may be hot point */ 2817 spin_lock(&sbi->s_md_lock); 2818 ac->ac_g_ex.fe_group = sbi->s_mb_last_group; 2819 ac->ac_g_ex.fe_start = sbi->s_mb_last_start; 2820 spin_unlock(&sbi->s_md_lock); 2821 } 2822 2823 /* 2824 * Let's just scan groups to find more-less suitable blocks We 2825 * start with CR_GOAL_LEN_FAST, unless it is power of 2 2826 * aligned, in which case let's do that faster approach first. 2827 */ 2828 if (ac->ac_2order) 2829 cr = CR_POWER2_ALIGNED; 2830 repeat: 2831 for (; cr < EXT4_MB_NUM_CRS && ac->ac_status == AC_STATUS_CONTINUE; cr++) { 2832 ac->ac_criteria = cr; 2833 /* 2834 * searching for the right group start 2835 * from the goal value specified 2836 */ 2837 group = ac->ac_g_ex.fe_group; 2838 ac->ac_groups_linear_remaining = sbi->s_mb_max_linear_groups; 2839 prefetch_grp = group; 2840 2841 for (i = 0, new_cr = cr; i < ngroups; i++, 2842 ext4_mb_choose_next_group(ac, &new_cr, &group, ngroups)) { 2843 int ret = 0; 2844 2845 cond_resched(); 2846 if (new_cr != cr) { 2847 cr = new_cr; 2848 goto repeat; 2849 } 2850 2851 /* 2852 * Batch reads of the block allocation bitmaps 2853 * to get multiple READs in flight; limit 2854 * prefetching at inexpensive CR, otherwise mballoc 2855 * can spend a lot of time loading imperfect groups 2856 */ 2857 if ((prefetch_grp == group) && 2858 (ext4_mb_cr_expensive(cr) || 2859 prefetch_ios < sbi->s_mb_prefetch_limit)) { 2860 nr = sbi->s_mb_prefetch; 2861 if (ext4_has_feature_flex_bg(sb)) { 2862 nr = 1 << sbi->s_log_groups_per_flex; 2863 nr -= group & (nr - 1); 2864 nr = min(nr, sbi->s_mb_prefetch); 2865 } 2866 prefetch_grp = ext4_mb_prefetch(sb, group, 2867 nr, &prefetch_ios); 2868 } 2869 2870 /* This now checks without needing the buddy page */ 2871 ret = ext4_mb_good_group_nolock(ac, group, cr); 2872 if (ret <= 0) { 2873 if (!first_err) 2874 first_err = ret; 2875 continue; 2876 } 2877 2878 err = ext4_mb_load_buddy(sb, group, &e4b); 2879 if (err) 2880 goto out; 2881 2882 ext4_lock_group(sb, group); 2883 2884 /* 2885 * We need to check again after locking the 2886 * block group 2887 */ 2888 ret = ext4_mb_good_group(ac, group, cr); 2889 if (ret == 0) { 2890 ext4_unlock_group(sb, group); 2891 ext4_mb_unload_buddy(&e4b); 2892 continue; 2893 } 2894 2895 ac->ac_groups_scanned++; 2896 if (cr == CR_POWER2_ALIGNED) 2897 ext4_mb_simple_scan_group(ac, &e4b); 2898 else if ((cr == CR_GOAL_LEN_FAST || 2899 cr == CR_BEST_AVAIL_LEN) && 2900 sbi->s_stripe && 2901 !(ac->ac_g_ex.fe_len % 2902 EXT4_B2C(sbi, sbi->s_stripe))) 2903 ext4_mb_scan_aligned(ac, &e4b); 2904 else 2905 ext4_mb_complex_scan_group(ac, &e4b); 2906 2907 ext4_unlock_group(sb, group); 2908 ext4_mb_unload_buddy(&e4b); 2909 2910 if (ac->ac_status != AC_STATUS_CONTINUE) 2911 break; 2912 } 2913 /* Processed all groups and haven't found blocks */ 2914 if (sbi->s_mb_stats && i == ngroups) 2915 atomic64_inc(&sbi->s_bal_cX_failed[cr]); 2916 2917 if (i == ngroups && ac->ac_criteria == CR_BEST_AVAIL_LEN) 2918 /* Reset goal length to original goal length before 2919 * falling into CR_GOAL_LEN_SLOW */ 2920 ac->ac_g_ex.fe_len = ac->ac_orig_goal_len; 2921 } 2922 2923 if (ac->ac_b_ex.fe_len > 0 && ac->ac_status != AC_STATUS_FOUND && 2924 !(ac->ac_flags & EXT4_MB_HINT_FIRST)) { 2925 /* 2926 * We've been searching too long. Let's try to allocate 2927 * the best chunk we've found so far 2928 */ 2929 ext4_mb_try_best_found(ac, &e4b); 2930 if (ac->ac_status != AC_STATUS_FOUND) { 2931 /* 2932 * Someone more lucky has already allocated it. 2933 * The only thing we can do is just take first 2934 * found block(s) 2935 */ 2936 lost = atomic_inc_return(&sbi->s_mb_lost_chunks); 2937 mb_debug(sb, "lost chunk, group: %u, start: %d, len: %d, lost: %d\n", 2938 ac->ac_b_ex.fe_group, ac->ac_b_ex.fe_start, 2939 ac->ac_b_ex.fe_len, lost); 2940 2941 ac->ac_b_ex.fe_group = 0; 2942 ac->ac_b_ex.fe_start = 0; 2943 ac->ac_b_ex.fe_len = 0; 2944 ac->ac_status = AC_STATUS_CONTINUE; 2945 ac->ac_flags |= EXT4_MB_HINT_FIRST; 2946 cr = CR_ANY_FREE; 2947 goto repeat; 2948 } 2949 } 2950 2951 if (sbi->s_mb_stats && ac->ac_status == AC_STATUS_FOUND) 2952 atomic64_inc(&sbi->s_bal_cX_hits[ac->ac_criteria]); 2953 out: 2954 if (!err && ac->ac_status != AC_STATUS_FOUND && first_err) 2955 err = first_err; 2956 2957 mb_debug(sb, "Best len %d, origin len %d, ac_status %u, ac_flags 0x%x, cr %d ret %d\n", 2958 ac->ac_b_ex.fe_len, ac->ac_o_ex.fe_len, ac->ac_status, 2959 ac->ac_flags, cr, err); 2960 2961 if (nr) 2962 ext4_mb_prefetch_fini(sb, prefetch_grp, nr); 2963 2964 return err; 2965 } 2966 2967 static void *ext4_mb_seq_groups_start(struct seq_file *seq, loff_t *pos) 2968 { 2969 struct super_block *sb = pde_data(file_inode(seq->file)); 2970 ext4_group_t group; 2971 2972 if (*pos < 0 || *pos >= ext4_get_groups_count(sb)) 2973 return NULL; 2974 group = *pos + 1; 2975 return (void *) ((unsigned long) group); 2976 } 2977 2978 static void *ext4_mb_seq_groups_next(struct seq_file *seq, void *v, loff_t *pos) 2979 { 2980 struct super_block *sb = pde_data(file_inode(seq->file)); 2981 ext4_group_t group; 2982 2983 ++*pos; 2984 if (*pos < 0 || *pos >= ext4_get_groups_count(sb)) 2985 return NULL; 2986 group = *pos + 1; 2987 return (void *) ((unsigned long) group); 2988 } 2989 2990 static int ext4_mb_seq_groups_show(struct seq_file *seq, void *v) 2991 { 2992 struct super_block *sb = pde_data(file_inode(seq->file)); 2993 ext4_group_t group = (ext4_group_t) ((unsigned long) v); 2994 int i; 2995 int err, buddy_loaded = 0; 2996 struct ext4_buddy e4b; 2997 struct ext4_group_info *grinfo; 2998 unsigned char blocksize_bits = min_t(unsigned char, 2999 sb->s_blocksize_bits, 3000 EXT4_MAX_BLOCK_LOG_SIZE); 3001 struct sg { 3002 struct ext4_group_info info; 3003 ext4_grpblk_t counters[EXT4_MAX_BLOCK_LOG_SIZE + 2]; 3004 } sg; 3005 3006 group--; 3007 if (group == 0) 3008 seq_puts(seq, "#group: free frags first [" 3009 " 2^0 2^1 2^2 2^3 2^4 2^5 2^6 " 3010 " 2^7 2^8 2^9 2^10 2^11 2^12 2^13 ]\n"); 3011 3012 i = (blocksize_bits + 2) * sizeof(sg.info.bb_counters[0]) + 3013 sizeof(struct ext4_group_info); 3014 3015 grinfo = ext4_get_group_info(sb, group); 3016 if (!grinfo) 3017 return 0; 3018 /* Load the group info in memory only if not already loaded. */ 3019 if (unlikely(EXT4_MB_GRP_NEED_INIT(grinfo))) { 3020 err = ext4_mb_load_buddy(sb, group, &e4b); 3021 if (err) { 3022 seq_printf(seq, "#%-5u: I/O error\n", group); 3023 return 0; 3024 } 3025 buddy_loaded = 1; 3026 } 3027 3028 memcpy(&sg, grinfo, i); 3029 3030 if (buddy_loaded) 3031 ext4_mb_unload_buddy(&e4b); 3032 3033 seq_printf(seq, "#%-5u: %-5u %-5u %-5u [", group, sg.info.bb_free, 3034 sg.info.bb_fragments, sg.info.bb_first_free); 3035 for (i = 0; i <= 13; i++) 3036 seq_printf(seq, " %-5u", i <= blocksize_bits + 1 ? 3037 sg.info.bb_counters[i] : 0); 3038 seq_puts(seq, " ]\n"); 3039 3040 return 0; 3041 } 3042 3043 static void ext4_mb_seq_groups_stop(struct seq_file *seq, void *v) 3044 { 3045 } 3046 3047 const struct seq_operations ext4_mb_seq_groups_ops = { 3048 .start = ext4_mb_seq_groups_start, 3049 .next = ext4_mb_seq_groups_next, 3050 .stop = ext4_mb_seq_groups_stop, 3051 .show = ext4_mb_seq_groups_show, 3052 }; 3053 3054 int ext4_seq_mb_stats_show(struct seq_file *seq, void *offset) 3055 { 3056 struct super_block *sb = seq->private; 3057 struct ext4_sb_info *sbi = EXT4_SB(sb); 3058 3059 seq_puts(seq, "mballoc:\n"); 3060 if (!sbi->s_mb_stats) { 3061 seq_puts(seq, "\tmb stats collection turned off.\n"); 3062 seq_puts( 3063 seq, 3064 "\tTo enable, please write \"1\" to sysfs file mb_stats.\n"); 3065 return 0; 3066 } 3067 seq_printf(seq, "\treqs: %u\n", atomic_read(&sbi->s_bal_reqs)); 3068 seq_printf(seq, "\tsuccess: %u\n", atomic_read(&sbi->s_bal_success)); 3069 3070 seq_printf(seq, "\tgroups_scanned: %u\n", 3071 atomic_read(&sbi->s_bal_groups_scanned)); 3072 3073 /* CR_POWER2_ALIGNED stats */ 3074 seq_puts(seq, "\tcr_p2_aligned_stats:\n"); 3075 seq_printf(seq, "\t\thits: %llu\n", 3076 atomic64_read(&sbi->s_bal_cX_hits[CR_POWER2_ALIGNED])); 3077 seq_printf( 3078 seq, "\t\tgroups_considered: %llu\n", 3079 atomic64_read( 3080 &sbi->s_bal_cX_groups_considered[CR_POWER2_ALIGNED])); 3081 seq_printf(seq, "\t\textents_scanned: %u\n", 3082 atomic_read(&sbi->s_bal_cX_ex_scanned[CR_POWER2_ALIGNED])); 3083 seq_printf(seq, "\t\tuseless_loops: %llu\n", 3084 atomic64_read(&sbi->s_bal_cX_failed[CR_POWER2_ALIGNED])); 3085 seq_printf(seq, "\t\tbad_suggestions: %u\n", 3086 atomic_read(&sbi->s_bal_p2_aligned_bad_suggestions)); 3087 3088 /* CR_GOAL_LEN_FAST stats */ 3089 seq_puts(seq, "\tcr_goal_fast_stats:\n"); 3090 seq_printf(seq, "\t\thits: %llu\n", 3091 atomic64_read(&sbi->s_bal_cX_hits[CR_GOAL_LEN_FAST])); 3092 seq_printf(seq, "\t\tgroups_considered: %llu\n", 3093 atomic64_read( 3094 &sbi->s_bal_cX_groups_considered[CR_GOAL_LEN_FAST])); 3095 seq_printf(seq, "\t\textents_scanned: %u\n", 3096 atomic_read(&sbi->s_bal_cX_ex_scanned[CR_GOAL_LEN_FAST])); 3097 seq_printf(seq, "\t\tuseless_loops: %llu\n", 3098 atomic64_read(&sbi->s_bal_cX_failed[CR_GOAL_LEN_FAST])); 3099 seq_printf(seq, "\t\tbad_suggestions: %u\n", 3100 atomic_read(&sbi->s_bal_goal_fast_bad_suggestions)); 3101 3102 /* CR_BEST_AVAIL_LEN stats */ 3103 seq_puts(seq, "\tcr_best_avail_stats:\n"); 3104 seq_printf(seq, "\t\thits: %llu\n", 3105 atomic64_read(&sbi->s_bal_cX_hits[CR_BEST_AVAIL_LEN])); 3106 seq_printf( 3107 seq, "\t\tgroups_considered: %llu\n", 3108 atomic64_read( 3109 &sbi->s_bal_cX_groups_considered[CR_BEST_AVAIL_LEN])); 3110 seq_printf(seq, "\t\textents_scanned: %u\n", 3111 atomic_read(&sbi->s_bal_cX_ex_scanned[CR_BEST_AVAIL_LEN])); 3112 seq_printf(seq, "\t\tuseless_loops: %llu\n", 3113 atomic64_read(&sbi->s_bal_cX_failed[CR_BEST_AVAIL_LEN])); 3114 seq_printf(seq, "\t\tbad_suggestions: %u\n", 3115 atomic_read(&sbi->s_bal_best_avail_bad_suggestions)); 3116 3117 /* CR_GOAL_LEN_SLOW stats */ 3118 seq_puts(seq, "\tcr_goal_slow_stats:\n"); 3119 seq_printf(seq, "\t\thits: %llu\n", 3120 atomic64_read(&sbi->s_bal_cX_hits[CR_GOAL_LEN_SLOW])); 3121 seq_printf(seq, "\t\tgroups_considered: %llu\n", 3122 atomic64_read( 3123 &sbi->s_bal_cX_groups_considered[CR_GOAL_LEN_SLOW])); 3124 seq_printf(seq, "\t\textents_scanned: %u\n", 3125 atomic_read(&sbi->s_bal_cX_ex_scanned[CR_GOAL_LEN_SLOW])); 3126 seq_printf(seq, "\t\tuseless_loops: %llu\n", 3127 atomic64_read(&sbi->s_bal_cX_failed[CR_GOAL_LEN_SLOW])); 3128 3129 /* CR_ANY_FREE stats */ 3130 seq_puts(seq, "\tcr_any_free_stats:\n"); 3131 seq_printf(seq, "\t\thits: %llu\n", 3132 atomic64_read(&sbi->s_bal_cX_hits[CR_ANY_FREE])); 3133 seq_printf( 3134 seq, "\t\tgroups_considered: %llu\n", 3135 atomic64_read(&sbi->s_bal_cX_groups_considered[CR_ANY_FREE])); 3136 seq_printf(seq, "\t\textents_scanned: %u\n", 3137 atomic_read(&sbi->s_bal_cX_ex_scanned[CR_ANY_FREE])); 3138 seq_printf(seq, "\t\tuseless_loops: %llu\n", 3139 atomic64_read(&sbi->s_bal_cX_failed[CR_ANY_FREE])); 3140 3141 /* Aggregates */ 3142 seq_printf(seq, "\textents_scanned: %u\n", 3143 atomic_read(&sbi->s_bal_ex_scanned)); 3144 seq_printf(seq, "\t\tgoal_hits: %u\n", atomic_read(&sbi->s_bal_goals)); 3145 seq_printf(seq, "\t\tlen_goal_hits: %u\n", 3146 atomic_read(&sbi->s_bal_len_goals)); 3147 seq_printf(seq, "\t\t2^n_hits: %u\n", atomic_read(&sbi->s_bal_2orders)); 3148 seq_printf(seq, "\t\tbreaks: %u\n", atomic_read(&sbi->s_bal_breaks)); 3149 seq_printf(seq, "\t\tlost: %u\n", atomic_read(&sbi->s_mb_lost_chunks)); 3150 seq_printf(seq, "\tbuddies_generated: %u/%u\n", 3151 atomic_read(&sbi->s_mb_buddies_generated), 3152 ext4_get_groups_count(sb)); 3153 seq_printf(seq, "\tbuddies_time_used: %llu\n", 3154 atomic64_read(&sbi->s_mb_generation_time)); 3155 seq_printf(seq, "\tpreallocated: %u\n", 3156 atomic_read(&sbi->s_mb_preallocated)); 3157 seq_printf(seq, "\tdiscarded: %u\n", atomic_read(&sbi->s_mb_discarded)); 3158 return 0; 3159 } 3160 3161 static void *ext4_mb_seq_structs_summary_start(struct seq_file *seq, loff_t *pos) 3162 __acquires(&EXT4_SB(sb)->s_mb_rb_lock) 3163 { 3164 struct super_block *sb = pde_data(file_inode(seq->file)); 3165 unsigned long position; 3166 3167 if (*pos < 0 || *pos >= 2*MB_NUM_ORDERS(sb)) 3168 return NULL; 3169 position = *pos + 1; 3170 return (void *) ((unsigned long) position); 3171 } 3172 3173 static void *ext4_mb_seq_structs_summary_next(struct seq_file *seq, void *v, loff_t *pos) 3174 { 3175 struct super_block *sb = pde_data(file_inode(seq->file)); 3176 unsigned long position; 3177 3178 ++*pos; 3179 if (*pos < 0 || *pos >= 2*MB_NUM_ORDERS(sb)) 3180 return NULL; 3181 position = *pos + 1; 3182 return (void *) ((unsigned long) position); 3183 } 3184 3185 static int ext4_mb_seq_structs_summary_show(struct seq_file *seq, void *v) 3186 { 3187 struct super_block *sb = pde_data(file_inode(seq->file)); 3188 struct ext4_sb_info *sbi = EXT4_SB(sb); 3189 unsigned long position = ((unsigned long) v); 3190 struct ext4_group_info *grp; 3191 unsigned int count; 3192 3193 position--; 3194 if (position >= MB_NUM_ORDERS(sb)) { 3195 position -= MB_NUM_ORDERS(sb); 3196 if (position == 0) 3197 seq_puts(seq, "avg_fragment_size_lists:\n"); 3198 3199 count = 0; 3200 read_lock(&sbi->s_mb_avg_fragment_size_locks[position]); 3201 list_for_each_entry(grp, &sbi->s_mb_avg_fragment_size[position], 3202 bb_avg_fragment_size_node) 3203 count++; 3204 read_unlock(&sbi->s_mb_avg_fragment_size_locks[position]); 3205 seq_printf(seq, "\tlist_order_%u_groups: %u\n", 3206 (unsigned int)position, count); 3207 return 0; 3208 } 3209 3210 if (position == 0) { 3211 seq_printf(seq, "optimize_scan: %d\n", 3212 test_opt2(sb, MB_OPTIMIZE_SCAN) ? 1 : 0); 3213 seq_puts(seq, "max_free_order_lists:\n"); 3214 } 3215 count = 0; 3216 read_lock(&sbi->s_mb_largest_free_orders_locks[position]); 3217 list_for_each_entry(grp, &sbi->s_mb_largest_free_orders[position], 3218 bb_largest_free_order_node) 3219 count++; 3220 read_unlock(&sbi->s_mb_largest_free_orders_locks[position]); 3221 seq_printf(seq, "\tlist_order_%u_groups: %u\n", 3222 (unsigned int)position, count); 3223 3224 return 0; 3225 } 3226 3227 static void ext4_mb_seq_structs_summary_stop(struct seq_file *seq, void *v) 3228 { 3229 } 3230 3231 const struct seq_operations ext4_mb_seq_structs_summary_ops = { 3232 .start = ext4_mb_seq_structs_summary_start, 3233 .next = ext4_mb_seq_structs_summary_next, 3234 .stop = ext4_mb_seq_structs_summary_stop, 3235 .show = ext4_mb_seq_structs_summary_show, 3236 }; 3237 3238 static struct kmem_cache *get_groupinfo_cache(int blocksize_bits) 3239 { 3240 int cache_index = blocksize_bits - EXT4_MIN_BLOCK_LOG_SIZE; 3241 struct kmem_cache *cachep = ext4_groupinfo_caches[cache_index]; 3242 3243 BUG_ON(!cachep); 3244 return cachep; 3245 } 3246 3247 /* 3248 * Allocate the top-level s_group_info array for the specified number 3249 * of groups 3250 */ 3251 int ext4_mb_alloc_groupinfo(struct super_block *sb, ext4_group_t ngroups) 3252 { 3253 struct ext4_sb_info *sbi = EXT4_SB(sb); 3254 unsigned size; 3255 struct ext4_group_info ***old_groupinfo, ***new_groupinfo; 3256 3257 size = (ngroups + EXT4_DESC_PER_BLOCK(sb) - 1) >> 3258 EXT4_DESC_PER_BLOCK_BITS(sb); 3259 if (size <= sbi->s_group_info_size) 3260 return 0; 3261 3262 size = roundup_pow_of_two(sizeof(*sbi->s_group_info) * size); 3263 new_groupinfo = kvzalloc(size, GFP_KERNEL); 3264 if (!new_groupinfo) { 3265 ext4_msg(sb, KERN_ERR, "can't allocate buddy meta group"); 3266 return -ENOMEM; 3267 } 3268 rcu_read_lock(); 3269 old_groupinfo = rcu_dereference(sbi->s_group_info); 3270 if (old_groupinfo) 3271 memcpy(new_groupinfo, old_groupinfo, 3272 sbi->s_group_info_size * sizeof(*sbi->s_group_info)); 3273 rcu_read_unlock(); 3274 rcu_assign_pointer(sbi->s_group_info, new_groupinfo); 3275 sbi->s_group_info_size = size / sizeof(*sbi->s_group_info); 3276 if (old_groupinfo) 3277 ext4_kvfree_array_rcu(old_groupinfo); 3278 ext4_debug("allocated s_groupinfo array for %d meta_bg's\n", 3279 sbi->s_group_info_size); 3280 return 0; 3281 } 3282 3283 /* Create and initialize ext4_group_info data for the given group. */ 3284 int ext4_mb_add_groupinfo(struct super_block *sb, ext4_group_t group, 3285 struct ext4_group_desc *desc) 3286 { 3287 int i; 3288 int metalen = 0; 3289 int idx = group >> EXT4_DESC_PER_BLOCK_BITS(sb); 3290 struct ext4_sb_info *sbi = EXT4_SB(sb); 3291 struct ext4_group_info **meta_group_info; 3292 struct kmem_cache *cachep = get_groupinfo_cache(sb->s_blocksize_bits); 3293 3294 /* 3295 * First check if this group is the first of a reserved block. 3296 * If it's true, we have to allocate a new table of pointers 3297 * to ext4_group_info structures 3298 */ 3299 if (group % EXT4_DESC_PER_BLOCK(sb) == 0) { 3300 metalen = sizeof(*meta_group_info) << 3301 EXT4_DESC_PER_BLOCK_BITS(sb); 3302 meta_group_info = kmalloc(metalen, GFP_NOFS); 3303 if (meta_group_info == NULL) { 3304 ext4_msg(sb, KERN_ERR, "can't allocate mem " 3305 "for a buddy group"); 3306 return -ENOMEM; 3307 } 3308 rcu_read_lock(); 3309 rcu_dereference(sbi->s_group_info)[idx] = meta_group_info; 3310 rcu_read_unlock(); 3311 } 3312 3313 meta_group_info = sbi_array_rcu_deref(sbi, s_group_info, idx); 3314 i = group & (EXT4_DESC_PER_BLOCK(sb) - 1); 3315 3316 meta_group_info[i] = kmem_cache_zalloc(cachep, GFP_NOFS); 3317 if (meta_group_info[i] == NULL) { 3318 ext4_msg(sb, KERN_ERR, "can't allocate buddy mem"); 3319 goto exit_group_info; 3320 } 3321 set_bit(EXT4_GROUP_INFO_NEED_INIT_BIT, 3322 &(meta_group_info[i]->bb_state)); 3323 3324 /* 3325 * initialize bb_free to be able to skip 3326 * empty groups without initialization 3327 */ 3328 if (ext4_has_group_desc_csum(sb) && 3329 (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT))) { 3330 meta_group_info[i]->bb_free = 3331 ext4_free_clusters_after_init(sb, group, desc); 3332 } else { 3333 meta_group_info[i]->bb_free = 3334 ext4_free_group_clusters(sb, desc); 3335 } 3336 3337 INIT_LIST_HEAD(&meta_group_info[i]->bb_prealloc_list); 3338 init_rwsem(&meta_group_info[i]->alloc_sem); 3339 meta_group_info[i]->bb_free_root = RB_ROOT; 3340 INIT_LIST_HEAD(&meta_group_info[i]->bb_largest_free_order_node); 3341 INIT_LIST_HEAD(&meta_group_info[i]->bb_avg_fragment_size_node); 3342 meta_group_info[i]->bb_largest_free_order = -1; /* uninit */ 3343 meta_group_info[i]->bb_avg_fragment_size_order = -1; /* uninit */ 3344 meta_group_info[i]->bb_group = group; 3345 3346 mb_group_bb_bitmap_alloc(sb, meta_group_info[i], group); 3347 return 0; 3348 3349 exit_group_info: 3350 /* If a meta_group_info table has been allocated, release it now */ 3351 if (group % EXT4_DESC_PER_BLOCK(sb) == 0) { 3352 struct ext4_group_info ***group_info; 3353 3354 rcu_read_lock(); 3355 group_info = rcu_dereference(sbi->s_group_info); 3356 kfree(group_info[idx]); 3357 group_info[idx] = NULL; 3358 rcu_read_unlock(); 3359 } 3360 return -ENOMEM; 3361 } /* ext4_mb_add_groupinfo */ 3362 3363 static int ext4_mb_init_backend(struct super_block *sb) 3364 { 3365 ext4_group_t ngroups = ext4_get_groups_count(sb); 3366 ext4_group_t i; 3367 struct ext4_sb_info *sbi = EXT4_SB(sb); 3368 int err; 3369 struct ext4_group_desc *desc; 3370 struct ext4_group_info ***group_info; 3371 struct kmem_cache *cachep; 3372 3373 err = ext4_mb_alloc_groupinfo(sb, ngroups); 3374 if (err) 3375 return err; 3376 3377 sbi->s_buddy_cache = new_inode(sb); 3378 if (sbi->s_buddy_cache == NULL) { 3379 ext4_msg(sb, KERN_ERR, "can't get new inode"); 3380 goto err_freesgi; 3381 } 3382 /* To avoid potentially colliding with an valid on-disk inode number, 3383 * use EXT4_BAD_INO for the buddy cache inode number. This inode is 3384 * not in the inode hash, so it should never be found by iget(), but 3385 * this will avoid confusion if it ever shows up during debugging. */ 3386 sbi->s_buddy_cache->i_ino = EXT4_BAD_INO; 3387 EXT4_I(sbi->s_buddy_cache)->i_disksize = 0; 3388 for (i = 0; i < ngroups; i++) { 3389 cond_resched(); 3390 desc = ext4_get_group_desc(sb, i, NULL); 3391 if (desc == NULL) { 3392 ext4_msg(sb, KERN_ERR, "can't read descriptor %u", i); 3393 goto err_freebuddy; 3394 } 3395 if (ext4_mb_add_groupinfo(sb, i, desc) != 0) 3396 goto err_freebuddy; 3397 } 3398 3399 if (ext4_has_feature_flex_bg(sb)) { 3400 /* a single flex group is supposed to be read by a single IO. 3401 * 2 ^ s_log_groups_per_flex != UINT_MAX as s_mb_prefetch is 3402 * unsigned integer, so the maximum shift is 32. 3403 */ 3404 if (sbi->s_es->s_log_groups_per_flex >= 32) { 3405 ext4_msg(sb, KERN_ERR, "too many log groups per flexible block group"); 3406 goto err_freebuddy; 3407 } 3408 sbi->s_mb_prefetch = min_t(uint, 1 << sbi->s_es->s_log_groups_per_flex, 3409 BLK_MAX_SEGMENT_SIZE >> (sb->s_blocksize_bits - 9)); 3410 sbi->s_mb_prefetch *= 8; /* 8 prefetch IOs in flight at most */ 3411 } else { 3412 sbi->s_mb_prefetch = 32; 3413 } 3414 if (sbi->s_mb_prefetch > ext4_get_groups_count(sb)) 3415 sbi->s_mb_prefetch = ext4_get_groups_count(sb); 3416 /* now many real IOs to prefetch within a single allocation at cr=0 3417 * given cr=0 is an CPU-related optimization we shouldn't try to 3418 * load too many groups, at some point we should start to use what 3419 * we've got in memory. 3420 * with an average random access time 5ms, it'd take a second to get 3421 * 200 groups (* N with flex_bg), so let's make this limit 4 3422 */ 3423 sbi->s_mb_prefetch_limit = sbi->s_mb_prefetch * 4; 3424 if (sbi->s_mb_prefetch_limit > ext4_get_groups_count(sb)) 3425 sbi->s_mb_prefetch_limit = ext4_get_groups_count(sb); 3426 3427 return 0; 3428 3429 err_freebuddy: 3430 cachep = get_groupinfo_cache(sb->s_blocksize_bits); 3431 while (i-- > 0) { 3432 struct ext4_group_info *grp = ext4_get_group_info(sb, i); 3433 3434 if (grp) 3435 kmem_cache_free(cachep, grp); 3436 } 3437 i = sbi->s_group_info_size; 3438 rcu_read_lock(); 3439 group_info = rcu_dereference(sbi->s_group_info); 3440 while (i-- > 0) 3441 kfree(group_info[i]); 3442 rcu_read_unlock(); 3443 iput(sbi->s_buddy_cache); 3444 err_freesgi: 3445 rcu_read_lock(); 3446 kvfree(rcu_dereference(sbi->s_group_info)); 3447 rcu_read_unlock(); 3448 return -ENOMEM; 3449 } 3450 3451 static void ext4_groupinfo_destroy_slabs(void) 3452 { 3453 int i; 3454 3455 for (i = 0; i < NR_GRPINFO_CACHES; i++) { 3456 kmem_cache_destroy(ext4_groupinfo_caches[i]); 3457 ext4_groupinfo_caches[i] = NULL; 3458 } 3459 } 3460 3461 static int ext4_groupinfo_create_slab(size_t size) 3462 { 3463 static DEFINE_MUTEX(ext4_grpinfo_slab_create_mutex); 3464 int slab_size; 3465 int blocksize_bits = order_base_2(size); 3466 int cache_index = blocksize_bits - EXT4_MIN_BLOCK_LOG_SIZE; 3467 struct kmem_cache *cachep; 3468 3469 if (cache_index >= NR_GRPINFO_CACHES) 3470 return -EINVAL; 3471 3472 if (unlikely(cache_index < 0)) 3473 cache_index = 0; 3474 3475 mutex_lock(&ext4_grpinfo_slab_create_mutex); 3476 if (ext4_groupinfo_caches[cache_index]) { 3477 mutex_unlock(&ext4_grpinfo_slab_create_mutex); 3478 return 0; /* Already created */ 3479 } 3480 3481 slab_size = offsetof(struct ext4_group_info, 3482 bb_counters[blocksize_bits + 2]); 3483 3484 cachep = kmem_cache_create(ext4_groupinfo_slab_names[cache_index], 3485 slab_size, 0, SLAB_RECLAIM_ACCOUNT, 3486 NULL); 3487 3488 ext4_groupinfo_caches[cache_index] = cachep; 3489 3490 mutex_unlock(&ext4_grpinfo_slab_create_mutex); 3491 if (!cachep) { 3492 printk(KERN_EMERG 3493 "EXT4-fs: no memory for groupinfo slab cache\n"); 3494 return -ENOMEM; 3495 } 3496 3497 return 0; 3498 } 3499 3500 static void ext4_discard_work(struct work_struct *work) 3501 { 3502 struct ext4_sb_info *sbi = container_of(work, 3503 struct ext4_sb_info, s_discard_work); 3504 struct super_block *sb = sbi->s_sb; 3505 struct ext4_free_data *fd, *nfd; 3506 struct ext4_buddy e4b; 3507 LIST_HEAD(discard_list); 3508 ext4_group_t grp, load_grp; 3509 int err = 0; 3510 3511 spin_lock(&sbi->s_md_lock); 3512 list_splice_init(&sbi->s_discard_list, &discard_list); 3513 spin_unlock(&sbi->s_md_lock); 3514 3515 load_grp = UINT_MAX; 3516 list_for_each_entry_safe(fd, nfd, &discard_list, efd_list) { 3517 /* 3518 * If filesystem is umounting or no memory or suffering 3519 * from no space, give up the discard 3520 */ 3521 if ((sb->s_flags & SB_ACTIVE) && !err && 3522 !atomic_read(&sbi->s_retry_alloc_pending)) { 3523 grp = fd->efd_group; 3524 if (grp != load_grp) { 3525 if (load_grp != UINT_MAX) 3526 ext4_mb_unload_buddy(&e4b); 3527 3528 err = ext4_mb_load_buddy(sb, grp, &e4b); 3529 if (err) { 3530 kmem_cache_free(ext4_free_data_cachep, fd); 3531 load_grp = UINT_MAX; 3532 continue; 3533 } else { 3534 load_grp = grp; 3535 } 3536 } 3537 3538 ext4_lock_group(sb, grp); 3539 ext4_try_to_trim_range(sb, &e4b, fd->efd_start_cluster, 3540 fd->efd_start_cluster + fd->efd_count - 1, 1); 3541 ext4_unlock_group(sb, grp); 3542 } 3543 kmem_cache_free(ext4_free_data_cachep, fd); 3544 } 3545 3546 if (load_grp != UINT_MAX) 3547 ext4_mb_unload_buddy(&e4b); 3548 } 3549 3550 int ext4_mb_init(struct super_block *sb) 3551 { 3552 struct ext4_sb_info *sbi = EXT4_SB(sb); 3553 unsigned i, j; 3554 unsigned offset, offset_incr; 3555 unsigned max; 3556 int ret; 3557 3558 i = MB_NUM_ORDERS(sb) * sizeof(*sbi->s_mb_offsets); 3559 3560 sbi->s_mb_offsets = kmalloc(i, GFP_KERNEL); 3561 if (sbi->s_mb_offsets == NULL) { 3562 ret = -ENOMEM; 3563 goto out; 3564 } 3565 3566 i = MB_NUM_ORDERS(sb) * sizeof(*sbi->s_mb_maxs); 3567 sbi->s_mb_maxs = kmalloc(i, GFP_KERNEL); 3568 if (sbi->s_mb_maxs == NULL) { 3569 ret = -ENOMEM; 3570 goto out; 3571 } 3572 3573 ret = ext4_groupinfo_create_slab(sb->s_blocksize); 3574 if (ret < 0) 3575 goto out; 3576 3577 /* order 0 is regular bitmap */ 3578 sbi->s_mb_maxs[0] = sb->s_blocksize << 3; 3579 sbi->s_mb_offsets[0] = 0; 3580 3581 i = 1; 3582 offset = 0; 3583 offset_incr = 1 << (sb->s_blocksize_bits - 1); 3584 max = sb->s_blocksize << 2; 3585 do { 3586 sbi->s_mb_offsets[i] = offset; 3587 sbi->s_mb_maxs[i] = max; 3588 offset += offset_incr; 3589 offset_incr = offset_incr >> 1; 3590 max = max >> 1; 3591 i++; 3592 } while (i < MB_NUM_ORDERS(sb)); 3593 3594 sbi->s_mb_avg_fragment_size = 3595 kmalloc_array(MB_NUM_ORDERS(sb), sizeof(struct list_head), 3596 GFP_KERNEL); 3597 if (!sbi->s_mb_avg_fragment_size) { 3598 ret = -ENOMEM; 3599 goto out; 3600 } 3601 sbi->s_mb_avg_fragment_size_locks = 3602 kmalloc_array(MB_NUM_ORDERS(sb), sizeof(rwlock_t), 3603 GFP_KERNEL); 3604 if (!sbi->s_mb_avg_fragment_size_locks) { 3605 ret = -ENOMEM; 3606 goto out; 3607 } 3608 for (i = 0; i < MB_NUM_ORDERS(sb); i++) { 3609 INIT_LIST_HEAD(&sbi->s_mb_avg_fragment_size[i]); 3610 rwlock_init(&sbi->s_mb_avg_fragment_size_locks[i]); 3611 } 3612 sbi->s_mb_largest_free_orders = 3613 kmalloc_array(MB_NUM_ORDERS(sb), sizeof(struct list_head), 3614 GFP_KERNEL); 3615 if (!sbi->s_mb_largest_free_orders) { 3616 ret = -ENOMEM; 3617 goto out; 3618 } 3619 sbi->s_mb_largest_free_orders_locks = 3620 kmalloc_array(MB_NUM_ORDERS(sb), sizeof(rwlock_t), 3621 GFP_KERNEL); 3622 if (!sbi->s_mb_largest_free_orders_locks) { 3623 ret = -ENOMEM; 3624 goto out; 3625 } 3626 for (i = 0; i < MB_NUM_ORDERS(sb); i++) { 3627 INIT_LIST_HEAD(&sbi->s_mb_largest_free_orders[i]); 3628 rwlock_init(&sbi->s_mb_largest_free_orders_locks[i]); 3629 } 3630 3631 spin_lock_init(&sbi->s_md_lock); 3632 sbi->s_mb_free_pending = 0; 3633 INIT_LIST_HEAD(&sbi->s_freed_data_list[0]); 3634 INIT_LIST_HEAD(&sbi->s_freed_data_list[1]); 3635 INIT_LIST_HEAD(&sbi->s_discard_list); 3636 INIT_WORK(&sbi->s_discard_work, ext4_discard_work); 3637 atomic_set(&sbi->s_retry_alloc_pending, 0); 3638 3639 sbi->s_mb_max_to_scan = MB_DEFAULT_MAX_TO_SCAN; 3640 sbi->s_mb_min_to_scan = MB_DEFAULT_MIN_TO_SCAN; 3641 sbi->s_mb_stats = MB_DEFAULT_STATS; 3642 sbi->s_mb_stream_request = MB_DEFAULT_STREAM_THRESHOLD; 3643 sbi->s_mb_order2_reqs = MB_DEFAULT_ORDER2_REQS; 3644 sbi->s_mb_best_avail_max_trim_order = MB_DEFAULT_BEST_AVAIL_TRIM_ORDER; 3645 3646 /* 3647 * The default group preallocation is 512, which for 4k block 3648 * sizes translates to 2 megabytes. However for bigalloc file 3649 * systems, this is probably too big (i.e, if the cluster size 3650 * is 1 megabyte, then group preallocation size becomes half a 3651 * gigabyte!). As a default, we will keep a two megabyte 3652 * group pralloc size for cluster sizes up to 64k, and after 3653 * that, we will force a minimum group preallocation size of 3654 * 32 clusters. This translates to 8 megs when the cluster 3655 * size is 256k, and 32 megs when the cluster size is 1 meg, 3656 * which seems reasonable as a default. 3657 */ 3658 sbi->s_mb_group_prealloc = max(MB_DEFAULT_GROUP_PREALLOC >> 3659 sbi->s_cluster_bits, 32); 3660 /* 3661 * If there is a s_stripe > 1, then we set the s_mb_group_prealloc 3662 * to the lowest multiple of s_stripe which is bigger than 3663 * the s_mb_group_prealloc as determined above. We want 3664 * the preallocation size to be an exact multiple of the 3665 * RAID stripe size so that preallocations don't fragment 3666 * the stripes. 3667 */ 3668 if (sbi->s_stripe > 1) { 3669 sbi->s_mb_group_prealloc = roundup( 3670 sbi->s_mb_group_prealloc, EXT4_B2C(sbi, sbi->s_stripe)); 3671 } 3672 3673 sbi->s_locality_groups = alloc_percpu(struct ext4_locality_group); 3674 if (sbi->s_locality_groups == NULL) { 3675 ret = -ENOMEM; 3676 goto out; 3677 } 3678 for_each_possible_cpu(i) { 3679 struct ext4_locality_group *lg; 3680 lg = per_cpu_ptr(sbi->s_locality_groups, i); 3681 mutex_init(&lg->lg_mutex); 3682 for (j = 0; j < PREALLOC_TB_SIZE; j++) 3683 INIT_LIST_HEAD(&lg->lg_prealloc_list[j]); 3684 spin_lock_init(&lg->lg_prealloc_lock); 3685 } 3686 3687 if (bdev_nonrot(sb->s_bdev)) 3688 sbi->s_mb_max_linear_groups = 0; 3689 else 3690 sbi->s_mb_max_linear_groups = MB_DEFAULT_LINEAR_LIMIT; 3691 /* init file for buddy data */ 3692 ret = ext4_mb_init_backend(sb); 3693 if (ret != 0) 3694 goto out_free_locality_groups; 3695 3696 return 0; 3697 3698 out_free_locality_groups: 3699 free_percpu(sbi->s_locality_groups); 3700 sbi->s_locality_groups = NULL; 3701 out: 3702 kfree(sbi->s_mb_avg_fragment_size); 3703 kfree(sbi->s_mb_avg_fragment_size_locks); 3704 kfree(sbi->s_mb_largest_free_orders); 3705 kfree(sbi->s_mb_largest_free_orders_locks); 3706 kfree(sbi->s_mb_offsets); 3707 sbi->s_mb_offsets = NULL; 3708 kfree(sbi->s_mb_maxs); 3709 sbi->s_mb_maxs = NULL; 3710 return ret; 3711 } 3712 3713 /* need to called with the ext4 group lock held */ 3714 static int ext4_mb_cleanup_pa(struct ext4_group_info *grp) 3715 { 3716 struct ext4_prealloc_space *pa; 3717 struct list_head *cur, *tmp; 3718 int count = 0; 3719 3720 list_for_each_safe(cur, tmp, &grp->bb_prealloc_list) { 3721 pa = list_entry(cur, struct ext4_prealloc_space, pa_group_list); 3722 list_del(&pa->pa_group_list); 3723 count++; 3724 kmem_cache_free(ext4_pspace_cachep, pa); 3725 } 3726 return count; 3727 } 3728 3729 int ext4_mb_release(struct super_block *sb) 3730 { 3731 ext4_group_t ngroups = ext4_get_groups_count(sb); 3732 ext4_group_t i; 3733 int num_meta_group_infos; 3734 struct ext4_group_info *grinfo, ***group_info; 3735 struct ext4_sb_info *sbi = EXT4_SB(sb); 3736 struct kmem_cache *cachep = get_groupinfo_cache(sb->s_blocksize_bits); 3737 int count; 3738 3739 if (test_opt(sb, DISCARD)) { 3740 /* 3741 * wait the discard work to drain all of ext4_free_data 3742 */ 3743 flush_work(&sbi->s_discard_work); 3744 WARN_ON_ONCE(!list_empty(&sbi->s_discard_list)); 3745 } 3746 3747 if (sbi->s_group_info) { 3748 for (i = 0; i < ngroups; i++) { 3749 cond_resched(); 3750 grinfo = ext4_get_group_info(sb, i); 3751 if (!grinfo) 3752 continue; 3753 mb_group_bb_bitmap_free(grinfo); 3754 ext4_lock_group(sb, i); 3755 count = ext4_mb_cleanup_pa(grinfo); 3756 if (count) 3757 mb_debug(sb, "mballoc: %d PAs left\n", 3758 count); 3759 ext4_unlock_group(sb, i); 3760 kmem_cache_free(cachep, grinfo); 3761 } 3762 num_meta_group_infos = (ngroups + 3763 EXT4_DESC_PER_BLOCK(sb) - 1) >> 3764 EXT4_DESC_PER_BLOCK_BITS(sb); 3765 rcu_read_lock(); 3766 group_info = rcu_dereference(sbi->s_group_info); 3767 for (i = 0; i < num_meta_group_infos; i++) 3768 kfree(group_info[i]); 3769 kvfree(group_info); 3770 rcu_read_unlock(); 3771 } 3772 kfree(sbi->s_mb_avg_fragment_size); 3773 kfree(sbi->s_mb_avg_fragment_size_locks); 3774 kfree(sbi->s_mb_largest_free_orders); 3775 kfree(sbi->s_mb_largest_free_orders_locks); 3776 kfree(sbi->s_mb_offsets); 3777 kfree(sbi->s_mb_maxs); 3778 iput(sbi->s_buddy_cache); 3779 if (sbi->s_mb_stats) { 3780 ext4_msg(sb, KERN_INFO, 3781 "mballoc: %u blocks %u reqs (%u success)", 3782 atomic_read(&sbi->s_bal_allocated), 3783 atomic_read(&sbi->s_bal_reqs), 3784 atomic_read(&sbi->s_bal_success)); 3785 ext4_msg(sb, KERN_INFO, 3786 "mballoc: %u extents scanned, %u groups scanned, %u goal hits, " 3787 "%u 2^N hits, %u breaks, %u lost", 3788 atomic_read(&sbi->s_bal_ex_scanned), 3789 atomic_read(&sbi->s_bal_groups_scanned), 3790 atomic_read(&sbi->s_bal_goals), 3791 atomic_read(&sbi->s_bal_2orders), 3792 atomic_read(&sbi->s_bal_breaks), 3793 atomic_read(&sbi->s_mb_lost_chunks)); 3794 ext4_msg(sb, KERN_INFO, 3795 "mballoc: %u generated and it took %llu", 3796 atomic_read(&sbi->s_mb_buddies_generated), 3797 atomic64_read(&sbi->s_mb_generation_time)); 3798 ext4_msg(sb, KERN_INFO, 3799 "mballoc: %u preallocated, %u discarded", 3800 atomic_read(&sbi->s_mb_preallocated), 3801 atomic_read(&sbi->s_mb_discarded)); 3802 } 3803 3804 free_percpu(sbi->s_locality_groups); 3805 3806 return 0; 3807 } 3808 3809 static inline int ext4_issue_discard(struct super_block *sb, 3810 ext4_group_t block_group, ext4_grpblk_t cluster, int count, 3811 struct bio **biop) 3812 { 3813 ext4_fsblk_t discard_block; 3814 3815 discard_block = (EXT4_C2B(EXT4_SB(sb), cluster) + 3816 ext4_group_first_block_no(sb, block_group)); 3817 count = EXT4_C2B(EXT4_SB(sb), count); 3818 trace_ext4_discard_blocks(sb, 3819 (unsigned long long) discard_block, count); 3820 if (biop) { 3821 return __blkdev_issue_discard(sb->s_bdev, 3822 (sector_t)discard_block << (sb->s_blocksize_bits - 9), 3823 (sector_t)count << (sb->s_blocksize_bits - 9), 3824 GFP_NOFS, biop); 3825 } else 3826 return sb_issue_discard(sb, discard_block, count, GFP_NOFS, 0); 3827 } 3828 3829 static void ext4_free_data_in_buddy(struct super_block *sb, 3830 struct ext4_free_data *entry) 3831 { 3832 struct ext4_buddy e4b; 3833 struct ext4_group_info *db; 3834 int err, count = 0; 3835 3836 mb_debug(sb, "gonna free %u blocks in group %u (0x%p):", 3837 entry->efd_count, entry->efd_group, entry); 3838 3839 err = ext4_mb_load_buddy(sb, entry->efd_group, &e4b); 3840 /* we expect to find existing buddy because it's pinned */ 3841 BUG_ON(err != 0); 3842 3843 spin_lock(&EXT4_SB(sb)->s_md_lock); 3844 EXT4_SB(sb)->s_mb_free_pending -= entry->efd_count; 3845 spin_unlock(&EXT4_SB(sb)->s_md_lock); 3846 3847 db = e4b.bd_info; 3848 /* there are blocks to put in buddy to make them really free */ 3849 count += entry->efd_count; 3850 ext4_lock_group(sb, entry->efd_group); 3851 /* Take it out of per group rb tree */ 3852 rb_erase(&entry->efd_node, &(db->bb_free_root)); 3853 mb_free_blocks(NULL, &e4b, entry->efd_start_cluster, entry->efd_count); 3854 3855 /* 3856 * Clear the trimmed flag for the group so that the next 3857 * ext4_trim_fs can trim it. 3858 * If the volume is mounted with -o discard, online discard 3859 * is supported and the free blocks will be trimmed online. 3860 */ 3861 if (!test_opt(sb, DISCARD)) 3862 EXT4_MB_GRP_CLEAR_TRIMMED(db); 3863 3864 if (!db->bb_free_root.rb_node) { 3865 /* No more items in the per group rb tree 3866 * balance refcounts from ext4_mb_free_metadata() 3867 */ 3868 put_page(e4b.bd_buddy_page); 3869 put_page(e4b.bd_bitmap_page); 3870 } 3871 ext4_unlock_group(sb, entry->efd_group); 3872 ext4_mb_unload_buddy(&e4b); 3873 3874 mb_debug(sb, "freed %d blocks in 1 structures\n", count); 3875 } 3876 3877 /* 3878 * This function is called by the jbd2 layer once the commit has finished, 3879 * so we know we can free the blocks that were released with that commit. 3880 */ 3881 void ext4_process_freed_data(struct super_block *sb, tid_t commit_tid) 3882 { 3883 struct ext4_sb_info *sbi = EXT4_SB(sb); 3884 struct ext4_free_data *entry, *tmp; 3885 LIST_HEAD(freed_data_list); 3886 struct list_head *s_freed_head = &sbi->s_freed_data_list[commit_tid & 1]; 3887 bool wake; 3888 3889 list_replace_init(s_freed_head, &freed_data_list); 3890 3891 list_for_each_entry(entry, &freed_data_list, efd_list) 3892 ext4_free_data_in_buddy(sb, entry); 3893 3894 if (test_opt(sb, DISCARD)) { 3895 spin_lock(&sbi->s_md_lock); 3896 wake = list_empty(&sbi->s_discard_list); 3897 list_splice_tail(&freed_data_list, &sbi->s_discard_list); 3898 spin_unlock(&sbi->s_md_lock); 3899 if (wake) 3900 queue_work(system_unbound_wq, &sbi->s_discard_work); 3901 } else { 3902 list_for_each_entry_safe(entry, tmp, &freed_data_list, efd_list) 3903 kmem_cache_free(ext4_free_data_cachep, entry); 3904 } 3905 } 3906 3907 int __init ext4_init_mballoc(void) 3908 { 3909 ext4_pspace_cachep = KMEM_CACHE(ext4_prealloc_space, 3910 SLAB_RECLAIM_ACCOUNT); 3911 if (ext4_pspace_cachep == NULL) 3912 goto out; 3913 3914 ext4_ac_cachep = KMEM_CACHE(ext4_allocation_context, 3915 SLAB_RECLAIM_ACCOUNT); 3916 if (ext4_ac_cachep == NULL) 3917 goto out_pa_free; 3918 3919 ext4_free_data_cachep = KMEM_CACHE(ext4_free_data, 3920 SLAB_RECLAIM_ACCOUNT); 3921 if (ext4_free_data_cachep == NULL) 3922 goto out_ac_free; 3923 3924 return 0; 3925 3926 out_ac_free: 3927 kmem_cache_destroy(ext4_ac_cachep); 3928 out_pa_free: 3929 kmem_cache_destroy(ext4_pspace_cachep); 3930 out: 3931 return -ENOMEM; 3932 } 3933 3934 void ext4_exit_mballoc(void) 3935 { 3936 /* 3937 * Wait for completion of call_rcu()'s on ext4_pspace_cachep 3938 * before destroying the slab cache. 3939 */ 3940 rcu_barrier(); 3941 kmem_cache_destroy(ext4_pspace_cachep); 3942 kmem_cache_destroy(ext4_ac_cachep); 3943 kmem_cache_destroy(ext4_free_data_cachep); 3944 ext4_groupinfo_destroy_slabs(); 3945 } 3946 3947 #define EXT4_MB_BITMAP_MARKED_CHECK 0x0001 3948 #define EXT4_MB_SYNC_UPDATE 0x0002 3949 static int 3950 ext4_mb_mark_context(handle_t *handle, struct super_block *sb, bool state, 3951 ext4_group_t group, ext4_grpblk_t blkoff, 3952 ext4_grpblk_t len, int flags, ext4_grpblk_t *ret_changed) 3953 { 3954 struct ext4_sb_info *sbi = EXT4_SB(sb); 3955 struct buffer_head *bitmap_bh = NULL; 3956 struct ext4_group_desc *gdp; 3957 struct buffer_head *gdp_bh; 3958 int err; 3959 unsigned int i, already, changed = len; 3960 3961 KUNIT_STATIC_STUB_REDIRECT(ext4_mb_mark_context, 3962 handle, sb, state, group, blkoff, len, 3963 flags, ret_changed); 3964 3965 if (ret_changed) 3966 *ret_changed = 0; 3967 bitmap_bh = ext4_read_block_bitmap(sb, group); 3968 if (IS_ERR(bitmap_bh)) 3969 return PTR_ERR(bitmap_bh); 3970 3971 if (handle) { 3972 BUFFER_TRACE(bitmap_bh, "getting write access"); 3973 err = ext4_journal_get_write_access(handle, sb, bitmap_bh, 3974 EXT4_JTR_NONE); 3975 if (err) 3976 goto out_err; 3977 } 3978 3979 err = -EIO; 3980 gdp = ext4_get_group_desc(sb, group, &gdp_bh); 3981 if (!gdp) 3982 goto out_err; 3983 3984 if (handle) { 3985 BUFFER_TRACE(gdp_bh, "get_write_access"); 3986 err = ext4_journal_get_write_access(handle, sb, gdp_bh, 3987 EXT4_JTR_NONE); 3988 if (err) 3989 goto out_err; 3990 } 3991 3992 ext4_lock_group(sb, group); 3993 if (ext4_has_group_desc_csum(sb) && 3994 (gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT))) { 3995 gdp->bg_flags &= cpu_to_le16(~EXT4_BG_BLOCK_UNINIT); 3996 ext4_free_group_clusters_set(sb, gdp, 3997 ext4_free_clusters_after_init(sb, group, gdp)); 3998 } 3999 4000 if (flags & EXT4_MB_BITMAP_MARKED_CHECK) { 4001 already = 0; 4002 for (i = 0; i < len; i++) 4003 if (mb_test_bit(blkoff + i, bitmap_bh->b_data) == 4004 state) 4005 already++; 4006 changed = len - already; 4007 } 4008 4009 if (state) { 4010 mb_set_bits(bitmap_bh->b_data, blkoff, len); 4011 ext4_free_group_clusters_set(sb, gdp, 4012 ext4_free_group_clusters(sb, gdp) - changed); 4013 } else { 4014 mb_clear_bits(bitmap_bh->b_data, blkoff, len); 4015 ext4_free_group_clusters_set(sb, gdp, 4016 ext4_free_group_clusters(sb, gdp) + changed); 4017 } 4018 4019 ext4_block_bitmap_csum_set(sb, gdp, bitmap_bh); 4020 ext4_group_desc_csum_set(sb, group, gdp); 4021 ext4_unlock_group(sb, group); 4022 if (ret_changed) 4023 *ret_changed = changed; 4024 4025 if (sbi->s_log_groups_per_flex) { 4026 ext4_group_t flex_group = ext4_flex_group(sbi, group); 4027 struct flex_groups *fg = sbi_array_rcu_deref(sbi, 4028 s_flex_groups, flex_group); 4029 4030 if (state) 4031 atomic64_sub(changed, &fg->free_clusters); 4032 else 4033 atomic64_add(changed, &fg->free_clusters); 4034 } 4035 4036 err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh); 4037 if (err) 4038 goto out_err; 4039 err = ext4_handle_dirty_metadata(handle, NULL, gdp_bh); 4040 if (err) 4041 goto out_err; 4042 4043 if (flags & EXT4_MB_SYNC_UPDATE) { 4044 sync_dirty_buffer(bitmap_bh); 4045 sync_dirty_buffer(gdp_bh); 4046 } 4047 4048 out_err: 4049 brelse(bitmap_bh); 4050 return err; 4051 } 4052 4053 /* 4054 * Check quota and mark chosen space (ac->ac_b_ex) non-free in bitmaps 4055 * Returns 0 if success or error code 4056 */ 4057 static noinline_for_stack int 4058 ext4_mb_mark_diskspace_used(struct ext4_allocation_context *ac, 4059 handle_t *handle, unsigned int reserv_clstrs) 4060 { 4061 struct ext4_group_desc *gdp; 4062 struct ext4_sb_info *sbi; 4063 struct super_block *sb; 4064 ext4_fsblk_t block; 4065 int err, len; 4066 int flags = 0; 4067 ext4_grpblk_t changed; 4068 4069 BUG_ON(ac->ac_status != AC_STATUS_FOUND); 4070 BUG_ON(ac->ac_b_ex.fe_len <= 0); 4071 4072 sb = ac->ac_sb; 4073 sbi = EXT4_SB(sb); 4074 4075 gdp = ext4_get_group_desc(sb, ac->ac_b_ex.fe_group, NULL); 4076 if (!gdp) 4077 return -EIO; 4078 ext4_debug("using block group %u(%d)\n", ac->ac_b_ex.fe_group, 4079 ext4_free_group_clusters(sb, gdp)); 4080 4081 block = ext4_grp_offs_to_block(sb, &ac->ac_b_ex); 4082 len = EXT4_C2B(sbi, ac->ac_b_ex.fe_len); 4083 if (!ext4_inode_block_valid(ac->ac_inode, block, len)) { 4084 ext4_error(sb, "Allocating blocks %llu-%llu which overlap " 4085 "fs metadata", block, block+len); 4086 /* File system mounted not to panic on error 4087 * Fix the bitmap and return EFSCORRUPTED 4088 * We leak some of the blocks here. 4089 */ 4090 err = ext4_mb_mark_context(handle, sb, true, 4091 ac->ac_b_ex.fe_group, 4092 ac->ac_b_ex.fe_start, 4093 ac->ac_b_ex.fe_len, 4094 0, NULL); 4095 if (!err) 4096 err = -EFSCORRUPTED; 4097 return err; 4098 } 4099 4100 #ifdef AGGRESSIVE_CHECK 4101 flags |= EXT4_MB_BITMAP_MARKED_CHECK; 4102 #endif 4103 err = ext4_mb_mark_context(handle, sb, true, ac->ac_b_ex.fe_group, 4104 ac->ac_b_ex.fe_start, ac->ac_b_ex.fe_len, 4105 flags, &changed); 4106 4107 if (err && changed == 0) 4108 return err; 4109 4110 #ifdef AGGRESSIVE_CHECK 4111 BUG_ON(changed != ac->ac_b_ex.fe_len); 4112 #endif 4113 percpu_counter_sub(&sbi->s_freeclusters_counter, ac->ac_b_ex.fe_len); 4114 /* 4115 * Now reduce the dirty block count also. Should not go negative 4116 */ 4117 if (!(ac->ac_flags & EXT4_MB_DELALLOC_RESERVED)) 4118 /* release all the reserved blocks if non delalloc */ 4119 percpu_counter_sub(&sbi->s_dirtyclusters_counter, 4120 reserv_clstrs); 4121 4122 return err; 4123 } 4124 4125 /* 4126 * Idempotent helper for Ext4 fast commit replay path to set the state of 4127 * blocks in bitmaps and update counters. 4128 */ 4129 void ext4_mb_mark_bb(struct super_block *sb, ext4_fsblk_t block, 4130 int len, bool state) 4131 { 4132 struct ext4_sb_info *sbi = EXT4_SB(sb); 4133 ext4_group_t group; 4134 ext4_grpblk_t blkoff; 4135 int err = 0; 4136 unsigned int clen, thisgrp_len; 4137 4138 while (len > 0) { 4139 ext4_get_group_no_and_offset(sb, block, &group, &blkoff); 4140 4141 /* 4142 * Check to see if we are freeing blocks across a group 4143 * boundary. 4144 * In case of flex_bg, this can happen that (block, len) may 4145 * span across more than one group. In that case we need to 4146 * get the corresponding group metadata to work with. 4147 * For this we have goto again loop. 4148 */ 4149 thisgrp_len = min_t(unsigned int, (unsigned int)len, 4150 EXT4_BLOCKS_PER_GROUP(sb) - EXT4_C2B(sbi, blkoff)); 4151 clen = EXT4_NUM_B2C(sbi, thisgrp_len); 4152 4153 if (!ext4_sb_block_valid(sb, NULL, block, thisgrp_len)) { 4154 ext4_error(sb, "Marking blocks in system zone - " 4155 "Block = %llu, len = %u", 4156 block, thisgrp_len); 4157 break; 4158 } 4159 4160 err = ext4_mb_mark_context(NULL, sb, state, 4161 group, blkoff, clen, 4162 EXT4_MB_BITMAP_MARKED_CHECK | 4163 EXT4_MB_SYNC_UPDATE, 4164 NULL); 4165 if (err) 4166 break; 4167 4168 block += thisgrp_len; 4169 len -= thisgrp_len; 4170 BUG_ON(len < 0); 4171 } 4172 } 4173 4174 /* 4175 * here we normalize request for locality group 4176 * Group request are normalized to s_mb_group_prealloc, which goes to 4177 * s_strip if we set the same via mount option. 4178 * s_mb_group_prealloc can be configured via 4179 * /sys/fs/ext4/<partition>/mb_group_prealloc 4180 * 4181 * XXX: should we try to preallocate more than the group has now? 4182 */ 4183 static void ext4_mb_normalize_group_request(struct ext4_allocation_context *ac) 4184 { 4185 struct super_block *sb = ac->ac_sb; 4186 struct ext4_locality_group *lg = ac->ac_lg; 4187 4188 BUG_ON(lg == NULL); 4189 ac->ac_g_ex.fe_len = EXT4_SB(sb)->s_mb_group_prealloc; 4190 mb_debug(sb, "goal %u blocks for locality group\n", ac->ac_g_ex.fe_len); 4191 } 4192 4193 /* 4194 * This function returns the next element to look at during inode 4195 * PA rbtree walk. We assume that we have held the inode PA rbtree lock 4196 * (ei->i_prealloc_lock) 4197 * 4198 * new_start The start of the range we want to compare 4199 * cur_start The existing start that we are comparing against 4200 * node The node of the rb_tree 4201 */ 4202 static inline struct rb_node* 4203 ext4_mb_pa_rb_next_iter(ext4_lblk_t new_start, ext4_lblk_t cur_start, struct rb_node *node) 4204 { 4205 if (new_start < cur_start) 4206 return node->rb_left; 4207 else 4208 return node->rb_right; 4209 } 4210 4211 static inline void 4212 ext4_mb_pa_assert_overlap(struct ext4_allocation_context *ac, 4213 ext4_lblk_t start, loff_t end) 4214 { 4215 struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb); 4216 struct ext4_inode_info *ei = EXT4_I(ac->ac_inode); 4217 struct ext4_prealloc_space *tmp_pa; 4218 ext4_lblk_t tmp_pa_start; 4219 loff_t tmp_pa_end; 4220 struct rb_node *iter; 4221 4222 read_lock(&ei->i_prealloc_lock); 4223 for (iter = ei->i_prealloc_node.rb_node; iter; 4224 iter = ext4_mb_pa_rb_next_iter(start, tmp_pa_start, iter)) { 4225 tmp_pa = rb_entry(iter, struct ext4_prealloc_space, 4226 pa_node.inode_node); 4227 tmp_pa_start = tmp_pa->pa_lstart; 4228 tmp_pa_end = pa_logical_end(sbi, tmp_pa); 4229 4230 spin_lock(&tmp_pa->pa_lock); 4231 if (tmp_pa->pa_deleted == 0) 4232 BUG_ON(!(start >= tmp_pa_end || end <= tmp_pa_start)); 4233 spin_unlock(&tmp_pa->pa_lock); 4234 } 4235 read_unlock(&ei->i_prealloc_lock); 4236 } 4237 4238 /* 4239 * Given an allocation context "ac" and a range "start", "end", check 4240 * and adjust boundaries if the range overlaps with any of the existing 4241 * preallocatoins stored in the corresponding inode of the allocation context. 4242 * 4243 * Parameters: 4244 * ac allocation context 4245 * start start of the new range 4246 * end end of the new range 4247 */ 4248 static inline void 4249 ext4_mb_pa_adjust_overlap(struct ext4_allocation_context *ac, 4250 ext4_lblk_t *start, loff_t *end) 4251 { 4252 struct ext4_inode_info *ei = EXT4_I(ac->ac_inode); 4253 struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb); 4254 struct ext4_prealloc_space *tmp_pa = NULL, *left_pa = NULL, *right_pa = NULL; 4255 struct rb_node *iter; 4256 ext4_lblk_t new_start, tmp_pa_start, right_pa_start = -1; 4257 loff_t new_end, tmp_pa_end, left_pa_end = -1; 4258 4259 new_start = *start; 4260 new_end = *end; 4261 4262 /* 4263 * Adjust the normalized range so that it doesn't overlap with any 4264 * existing preallocated blocks(PAs). Make sure to hold the rbtree lock 4265 * so it doesn't change underneath us. 4266 */ 4267 read_lock(&ei->i_prealloc_lock); 4268 4269 /* Step 1: find any one immediate neighboring PA of the normalized range */ 4270 for (iter = ei->i_prealloc_node.rb_node; iter; 4271 iter = ext4_mb_pa_rb_next_iter(ac->ac_o_ex.fe_logical, 4272 tmp_pa_start, iter)) { 4273 tmp_pa = rb_entry(iter, struct ext4_prealloc_space, 4274 pa_node.inode_node); 4275 tmp_pa_start = tmp_pa->pa_lstart; 4276 tmp_pa_end = pa_logical_end(sbi, tmp_pa); 4277 4278 /* PA must not overlap original request */ 4279 spin_lock(&tmp_pa->pa_lock); 4280 if (tmp_pa->pa_deleted == 0) 4281 BUG_ON(!(ac->ac_o_ex.fe_logical >= tmp_pa_end || 4282 ac->ac_o_ex.fe_logical < tmp_pa_start)); 4283 spin_unlock(&tmp_pa->pa_lock); 4284 } 4285 4286 /* 4287 * Step 2: check if the found PA is left or right neighbor and 4288 * get the other neighbor 4289 */ 4290 if (tmp_pa) { 4291 if (tmp_pa->pa_lstart < ac->ac_o_ex.fe_logical) { 4292 struct rb_node *tmp; 4293 4294 left_pa = tmp_pa; 4295 tmp = rb_next(&left_pa->pa_node.inode_node); 4296 if (tmp) { 4297 right_pa = rb_entry(tmp, 4298 struct ext4_prealloc_space, 4299 pa_node.inode_node); 4300 } 4301 } else { 4302 struct rb_node *tmp; 4303 4304 right_pa = tmp_pa; 4305 tmp = rb_prev(&right_pa->pa_node.inode_node); 4306 if (tmp) { 4307 left_pa = rb_entry(tmp, 4308 struct ext4_prealloc_space, 4309 pa_node.inode_node); 4310 } 4311 } 4312 } 4313 4314 /* Step 3: get the non deleted neighbors */ 4315 if (left_pa) { 4316 for (iter = &left_pa->pa_node.inode_node;; 4317 iter = rb_prev(iter)) { 4318 if (!iter) { 4319 left_pa = NULL; 4320 break; 4321 } 4322 4323 tmp_pa = rb_entry(iter, struct ext4_prealloc_space, 4324 pa_node.inode_node); 4325 left_pa = tmp_pa; 4326 spin_lock(&tmp_pa->pa_lock); 4327 if (tmp_pa->pa_deleted == 0) { 4328 spin_unlock(&tmp_pa->pa_lock); 4329 break; 4330 } 4331 spin_unlock(&tmp_pa->pa_lock); 4332 } 4333 } 4334 4335 if (right_pa) { 4336 for (iter = &right_pa->pa_node.inode_node;; 4337 iter = rb_next(iter)) { 4338 if (!iter) { 4339 right_pa = NULL; 4340 break; 4341 } 4342 4343 tmp_pa = rb_entry(iter, struct ext4_prealloc_space, 4344 pa_node.inode_node); 4345 right_pa = tmp_pa; 4346 spin_lock(&tmp_pa->pa_lock); 4347 if (tmp_pa->pa_deleted == 0) { 4348 spin_unlock(&tmp_pa->pa_lock); 4349 break; 4350 } 4351 spin_unlock(&tmp_pa->pa_lock); 4352 } 4353 } 4354 4355 if (left_pa) { 4356 left_pa_end = pa_logical_end(sbi, left_pa); 4357 BUG_ON(left_pa_end > ac->ac_o_ex.fe_logical); 4358 } 4359 4360 if (right_pa) { 4361 right_pa_start = right_pa->pa_lstart; 4362 BUG_ON(right_pa_start <= ac->ac_o_ex.fe_logical); 4363 } 4364 4365 /* Step 4: trim our normalized range to not overlap with the neighbors */ 4366 if (left_pa) { 4367 if (left_pa_end > new_start) 4368 new_start = left_pa_end; 4369 } 4370 4371 if (right_pa) { 4372 if (right_pa_start < new_end) 4373 new_end = right_pa_start; 4374 } 4375 read_unlock(&ei->i_prealloc_lock); 4376 4377 /* XXX: extra loop to check we really don't overlap preallocations */ 4378 ext4_mb_pa_assert_overlap(ac, new_start, new_end); 4379 4380 *start = new_start; 4381 *end = new_end; 4382 } 4383 4384 /* 4385 * Normalization means making request better in terms of 4386 * size and alignment 4387 */ 4388 static noinline_for_stack void 4389 ext4_mb_normalize_request(struct ext4_allocation_context *ac, 4390 struct ext4_allocation_request *ar) 4391 { 4392 struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb); 4393 struct ext4_super_block *es = sbi->s_es; 4394 int bsbits, max; 4395 loff_t size, start_off, end; 4396 loff_t orig_size __maybe_unused; 4397 ext4_lblk_t start; 4398 4399 /* do normalize only data requests, metadata requests 4400 do not need preallocation */ 4401 if (!(ac->ac_flags & EXT4_MB_HINT_DATA)) 4402 return; 4403 4404 /* sometime caller may want exact blocks */ 4405 if (unlikely(ac->ac_flags & EXT4_MB_HINT_GOAL_ONLY)) 4406 return; 4407 4408 /* caller may indicate that preallocation isn't 4409 * required (it's a tail, for example) */ 4410 if (ac->ac_flags & EXT4_MB_HINT_NOPREALLOC) 4411 return; 4412 4413 if (ac->ac_flags & EXT4_MB_HINT_GROUP_ALLOC) { 4414 ext4_mb_normalize_group_request(ac); 4415 return ; 4416 } 4417 4418 bsbits = ac->ac_sb->s_blocksize_bits; 4419 4420 /* first, let's learn actual file size 4421 * given current request is allocated */ 4422 size = extent_logical_end(sbi, &ac->ac_o_ex); 4423 size = size << bsbits; 4424 if (size < i_size_read(ac->ac_inode)) 4425 size = i_size_read(ac->ac_inode); 4426 orig_size = size; 4427 4428 /* max size of free chunks */ 4429 max = 2 << bsbits; 4430 4431 #define NRL_CHECK_SIZE(req, size, max, chunk_size) \ 4432 (req <= (size) || max <= (chunk_size)) 4433 4434 /* first, try to predict filesize */ 4435 /* XXX: should this table be tunable? */ 4436 start_off = 0; 4437 if (size <= 16 * 1024) { 4438 size = 16 * 1024; 4439 } else if (size <= 32 * 1024) { 4440 size = 32 * 1024; 4441 } else if (size <= 64 * 1024) { 4442 size = 64 * 1024; 4443 } else if (size <= 128 * 1024) { 4444 size = 128 * 1024; 4445 } else if (size <= 256 * 1024) { 4446 size = 256 * 1024; 4447 } else if (size <= 512 * 1024) { 4448 size = 512 * 1024; 4449 } else if (size <= 1024 * 1024) { 4450 size = 1024 * 1024; 4451 } else if (NRL_CHECK_SIZE(size, 4 * 1024 * 1024, max, 2 * 1024)) { 4452 start_off = ((loff_t)ac->ac_o_ex.fe_logical >> 4453 (21 - bsbits)) << 21; 4454 size = 2 * 1024 * 1024; 4455 } else if (NRL_CHECK_SIZE(size, 8 * 1024 * 1024, max, 4 * 1024)) { 4456 start_off = ((loff_t)ac->ac_o_ex.fe_logical >> 4457 (22 - bsbits)) << 22; 4458 size = 4 * 1024 * 1024; 4459 } else if (NRL_CHECK_SIZE(EXT4_C2B(sbi, ac->ac_o_ex.fe_len), 4460 (8<<20)>>bsbits, max, 8 * 1024)) { 4461 start_off = ((loff_t)ac->ac_o_ex.fe_logical >> 4462 (23 - bsbits)) << 23; 4463 size = 8 * 1024 * 1024; 4464 } else { 4465 start_off = (loff_t) ac->ac_o_ex.fe_logical << bsbits; 4466 size = (loff_t) EXT4_C2B(sbi, 4467 ac->ac_o_ex.fe_len) << bsbits; 4468 } 4469 size = size >> bsbits; 4470 start = start_off >> bsbits; 4471 4472 /* 4473 * For tiny groups (smaller than 8MB) the chosen allocation 4474 * alignment may be larger than group size. Make sure the 4475 * alignment does not move allocation to a different group which 4476 * makes mballoc fail assertions later. 4477 */ 4478 start = max(start, rounddown(ac->ac_o_ex.fe_logical, 4479 (ext4_lblk_t)EXT4_BLOCKS_PER_GROUP(ac->ac_sb))); 4480 4481 /* don't cover already allocated blocks in selected range */ 4482 if (ar->pleft && start <= ar->lleft) { 4483 size -= ar->lleft + 1 - start; 4484 start = ar->lleft + 1; 4485 } 4486 if (ar->pright && start + size - 1 >= ar->lright) 4487 size -= start + size - ar->lright; 4488 4489 /* 4490 * Trim allocation request for filesystems with artificially small 4491 * groups. 4492 */ 4493 if (size > EXT4_BLOCKS_PER_GROUP(ac->ac_sb)) 4494 size = EXT4_BLOCKS_PER_GROUP(ac->ac_sb); 4495 4496 end = start + size; 4497 4498 ext4_mb_pa_adjust_overlap(ac, &start, &end); 4499 4500 size = end - start; 4501 4502 /* 4503 * In this function "start" and "size" are normalized for better 4504 * alignment and length such that we could preallocate more blocks. 4505 * This normalization is done such that original request of 4506 * ac->ac_o_ex.fe_logical & fe_len should always lie within "start" and 4507 * "size" boundaries. 4508 * (Note fe_len can be relaxed since FS block allocation API does not 4509 * provide gurantee on number of contiguous blocks allocation since that 4510 * depends upon free space left, etc). 4511 * In case of inode pa, later we use the allocated blocks 4512 * [pa_pstart + fe_logical - pa_lstart, fe_len/size] from the preallocated 4513 * range of goal/best blocks [start, size] to put it at the 4514 * ac_o_ex.fe_logical extent of this inode. 4515 * (See ext4_mb_use_inode_pa() for more details) 4516 */ 4517 if (start + size <= ac->ac_o_ex.fe_logical || 4518 start > ac->ac_o_ex.fe_logical) { 4519 ext4_msg(ac->ac_sb, KERN_ERR, 4520 "start %lu, size %lu, fe_logical %lu", 4521 (unsigned long) start, (unsigned long) size, 4522 (unsigned long) ac->ac_o_ex.fe_logical); 4523 BUG(); 4524 } 4525 BUG_ON(size <= 0 || size > EXT4_BLOCKS_PER_GROUP(ac->ac_sb)); 4526 4527 /* now prepare goal request */ 4528 4529 /* XXX: is it better to align blocks WRT to logical 4530 * placement or satisfy big request as is */ 4531 ac->ac_g_ex.fe_logical = start; 4532 ac->ac_g_ex.fe_len = EXT4_NUM_B2C(sbi, size); 4533 ac->ac_orig_goal_len = ac->ac_g_ex.fe_len; 4534 4535 /* define goal start in order to merge */ 4536 if (ar->pright && (ar->lright == (start + size)) && 4537 ar->pright >= size && 4538 ar->pright - size >= le32_to_cpu(es->s_first_data_block)) { 4539 /* merge to the right */ 4540 ext4_get_group_no_and_offset(ac->ac_sb, ar->pright - size, 4541 &ac->ac_g_ex.fe_group, 4542 &ac->ac_g_ex.fe_start); 4543 ac->ac_flags |= EXT4_MB_HINT_TRY_GOAL; 4544 } 4545 if (ar->pleft && (ar->lleft + 1 == start) && 4546 ar->pleft + 1 < ext4_blocks_count(es)) { 4547 /* merge to the left */ 4548 ext4_get_group_no_and_offset(ac->ac_sb, ar->pleft + 1, 4549 &ac->ac_g_ex.fe_group, 4550 &ac->ac_g_ex.fe_start); 4551 ac->ac_flags |= EXT4_MB_HINT_TRY_GOAL; 4552 } 4553 4554 mb_debug(ac->ac_sb, "goal: %lld(was %lld) blocks at %u\n", size, 4555 orig_size, start); 4556 } 4557 4558 static void ext4_mb_collect_stats(struct ext4_allocation_context *ac) 4559 { 4560 struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb); 4561 4562 if (sbi->s_mb_stats && ac->ac_g_ex.fe_len >= 1) { 4563 atomic_inc(&sbi->s_bal_reqs); 4564 atomic_add(ac->ac_b_ex.fe_len, &sbi->s_bal_allocated); 4565 if (ac->ac_b_ex.fe_len >= ac->ac_o_ex.fe_len) 4566 atomic_inc(&sbi->s_bal_success); 4567 4568 atomic_add(ac->ac_found, &sbi->s_bal_ex_scanned); 4569 for (int i=0; i<EXT4_MB_NUM_CRS; i++) { 4570 atomic_add(ac->ac_cX_found[i], &sbi->s_bal_cX_ex_scanned[i]); 4571 } 4572 4573 atomic_add(ac->ac_groups_scanned, &sbi->s_bal_groups_scanned); 4574 if (ac->ac_g_ex.fe_start == ac->ac_b_ex.fe_start && 4575 ac->ac_g_ex.fe_group == ac->ac_b_ex.fe_group) 4576 atomic_inc(&sbi->s_bal_goals); 4577 /* did we allocate as much as normalizer originally wanted? */ 4578 if (ac->ac_f_ex.fe_len == ac->ac_orig_goal_len) 4579 atomic_inc(&sbi->s_bal_len_goals); 4580 4581 if (ac->ac_found > sbi->s_mb_max_to_scan) 4582 atomic_inc(&sbi->s_bal_breaks); 4583 } 4584 4585 if (ac->ac_op == EXT4_MB_HISTORY_ALLOC) 4586 trace_ext4_mballoc_alloc(ac); 4587 else 4588 trace_ext4_mballoc_prealloc(ac); 4589 } 4590 4591 /* 4592 * Called on failure; free up any blocks from the inode PA for this 4593 * context. We don't need this for MB_GROUP_PA because we only change 4594 * pa_free in ext4_mb_release_context(), but on failure, we've already 4595 * zeroed out ac->ac_b_ex.fe_len, so group_pa->pa_free is not changed. 4596 */ 4597 static void ext4_discard_allocated_blocks(struct ext4_allocation_context *ac) 4598 { 4599 struct ext4_prealloc_space *pa = ac->ac_pa; 4600 struct ext4_buddy e4b; 4601 int err; 4602 4603 if (pa == NULL) { 4604 if (ac->ac_f_ex.fe_len == 0) 4605 return; 4606 err = ext4_mb_load_buddy(ac->ac_sb, ac->ac_f_ex.fe_group, &e4b); 4607 if (WARN_RATELIMIT(err, 4608 "ext4: mb_load_buddy failed (%d)", err)) 4609 /* 4610 * This should never happen since we pin the 4611 * pages in the ext4_allocation_context so 4612 * ext4_mb_load_buddy() should never fail. 4613 */ 4614 return; 4615 ext4_lock_group(ac->ac_sb, ac->ac_f_ex.fe_group); 4616 mb_free_blocks(ac->ac_inode, &e4b, ac->ac_f_ex.fe_start, 4617 ac->ac_f_ex.fe_len); 4618 ext4_unlock_group(ac->ac_sb, ac->ac_f_ex.fe_group); 4619 ext4_mb_unload_buddy(&e4b); 4620 return; 4621 } 4622 if (pa->pa_type == MB_INODE_PA) { 4623 spin_lock(&pa->pa_lock); 4624 pa->pa_free += ac->ac_b_ex.fe_len; 4625 spin_unlock(&pa->pa_lock); 4626 } 4627 } 4628 4629 /* 4630 * use blocks preallocated to inode 4631 */ 4632 static void ext4_mb_use_inode_pa(struct ext4_allocation_context *ac, 4633 struct ext4_prealloc_space *pa) 4634 { 4635 struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb); 4636 ext4_fsblk_t start; 4637 ext4_fsblk_t end; 4638 int len; 4639 4640 /* found preallocated blocks, use them */ 4641 start = pa->pa_pstart + (ac->ac_o_ex.fe_logical - pa->pa_lstart); 4642 end = min(pa->pa_pstart + EXT4_C2B(sbi, pa->pa_len), 4643 start + EXT4_C2B(sbi, ac->ac_o_ex.fe_len)); 4644 len = EXT4_NUM_B2C(sbi, end - start); 4645 ext4_get_group_no_and_offset(ac->ac_sb, start, &ac->ac_b_ex.fe_group, 4646 &ac->ac_b_ex.fe_start); 4647 ac->ac_b_ex.fe_len = len; 4648 ac->ac_status = AC_STATUS_FOUND; 4649 ac->ac_pa = pa; 4650 4651 BUG_ON(start < pa->pa_pstart); 4652 BUG_ON(end > pa->pa_pstart + EXT4_C2B(sbi, pa->pa_len)); 4653 BUG_ON(pa->pa_free < len); 4654 BUG_ON(ac->ac_b_ex.fe_len <= 0); 4655 pa->pa_free -= len; 4656 4657 mb_debug(ac->ac_sb, "use %llu/%d from inode pa %p\n", start, len, pa); 4658 } 4659 4660 /* 4661 * use blocks preallocated to locality group 4662 */ 4663 static void ext4_mb_use_group_pa(struct ext4_allocation_context *ac, 4664 struct ext4_prealloc_space *pa) 4665 { 4666 unsigned int len = ac->ac_o_ex.fe_len; 4667 4668 ext4_get_group_no_and_offset(ac->ac_sb, pa->pa_pstart, 4669 &ac->ac_b_ex.fe_group, 4670 &ac->ac_b_ex.fe_start); 4671 ac->ac_b_ex.fe_len = len; 4672 ac->ac_status = AC_STATUS_FOUND; 4673 ac->ac_pa = pa; 4674 4675 /* we don't correct pa_pstart or pa_len here to avoid 4676 * possible race when the group is being loaded concurrently 4677 * instead we correct pa later, after blocks are marked 4678 * in on-disk bitmap -- see ext4_mb_release_context() 4679 * Other CPUs are prevented from allocating from this pa by lg_mutex 4680 */ 4681 mb_debug(ac->ac_sb, "use %u/%u from group pa %p\n", 4682 pa->pa_lstart, len, pa); 4683 } 4684 4685 /* 4686 * Return the prealloc space that have minimal distance 4687 * from the goal block. @cpa is the prealloc 4688 * space that is having currently known minimal distance 4689 * from the goal block. 4690 */ 4691 static struct ext4_prealloc_space * 4692 ext4_mb_check_group_pa(ext4_fsblk_t goal_block, 4693 struct ext4_prealloc_space *pa, 4694 struct ext4_prealloc_space *cpa) 4695 { 4696 ext4_fsblk_t cur_distance, new_distance; 4697 4698 if (cpa == NULL) { 4699 atomic_inc(&pa->pa_count); 4700 return pa; 4701 } 4702 cur_distance = abs(goal_block - cpa->pa_pstart); 4703 new_distance = abs(goal_block - pa->pa_pstart); 4704 4705 if (cur_distance <= new_distance) 4706 return cpa; 4707 4708 /* drop the previous reference */ 4709 atomic_dec(&cpa->pa_count); 4710 atomic_inc(&pa->pa_count); 4711 return pa; 4712 } 4713 4714 /* 4715 * check if found pa meets EXT4_MB_HINT_GOAL_ONLY 4716 */ 4717 static bool 4718 ext4_mb_pa_goal_check(struct ext4_allocation_context *ac, 4719 struct ext4_prealloc_space *pa) 4720 { 4721 struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb); 4722 ext4_fsblk_t start; 4723 4724 if (likely(!(ac->ac_flags & EXT4_MB_HINT_GOAL_ONLY))) 4725 return true; 4726 4727 /* 4728 * If EXT4_MB_HINT_GOAL_ONLY is set, ac_g_ex will not be adjusted 4729 * in ext4_mb_normalize_request and will keep same with ac_o_ex 4730 * from ext4_mb_initialize_context. Choose ac_g_ex here to keep 4731 * consistent with ext4_mb_find_by_goal. 4732 */ 4733 start = pa->pa_pstart + 4734 (ac->ac_g_ex.fe_logical - pa->pa_lstart); 4735 if (ext4_grp_offs_to_block(ac->ac_sb, &ac->ac_g_ex) != start) 4736 return false; 4737 4738 if (ac->ac_g_ex.fe_len > pa->pa_len - 4739 EXT4_B2C(sbi, ac->ac_g_ex.fe_logical - pa->pa_lstart)) 4740 return false; 4741 4742 return true; 4743 } 4744 4745 /* 4746 * search goal blocks in preallocated space 4747 */ 4748 static noinline_for_stack bool 4749 ext4_mb_use_preallocated(struct ext4_allocation_context *ac) 4750 { 4751 struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb); 4752 int order, i; 4753 struct ext4_inode_info *ei = EXT4_I(ac->ac_inode); 4754 struct ext4_locality_group *lg; 4755 struct ext4_prealloc_space *tmp_pa = NULL, *cpa = NULL; 4756 struct rb_node *iter; 4757 ext4_fsblk_t goal_block; 4758 4759 /* only data can be preallocated */ 4760 if (!(ac->ac_flags & EXT4_MB_HINT_DATA)) 4761 return false; 4762 4763 /* 4764 * first, try per-file preallocation by searching the inode pa rbtree. 4765 * 4766 * Here, we can't do a direct traversal of the tree because 4767 * ext4_mb_discard_group_preallocation() can paralelly mark the pa 4768 * deleted and that can cause direct traversal to skip some entries. 4769 */ 4770 read_lock(&ei->i_prealloc_lock); 4771 4772 if (RB_EMPTY_ROOT(&ei->i_prealloc_node)) { 4773 goto try_group_pa; 4774 } 4775 4776 /* 4777 * Step 1: Find a pa with logical start immediately adjacent to the 4778 * original logical start. This could be on the left or right. 4779 * 4780 * (tmp_pa->pa_lstart never changes so we can skip locking for it). 4781 */ 4782 for (iter = ei->i_prealloc_node.rb_node; iter; 4783 iter = ext4_mb_pa_rb_next_iter(ac->ac_o_ex.fe_logical, 4784 tmp_pa->pa_lstart, iter)) { 4785 tmp_pa = rb_entry(iter, struct ext4_prealloc_space, 4786 pa_node.inode_node); 4787 } 4788 4789 /* 4790 * Step 2: The adjacent pa might be to the right of logical start, find 4791 * the left adjacent pa. After this step we'd have a valid tmp_pa whose 4792 * logical start is towards the left of original request's logical start 4793 */ 4794 if (tmp_pa->pa_lstart > ac->ac_o_ex.fe_logical) { 4795 struct rb_node *tmp; 4796 tmp = rb_prev(&tmp_pa->pa_node.inode_node); 4797 4798 if (tmp) { 4799 tmp_pa = rb_entry(tmp, struct ext4_prealloc_space, 4800 pa_node.inode_node); 4801 } else { 4802 /* 4803 * If there is no adjacent pa to the left then finding 4804 * an overlapping pa is not possible hence stop searching 4805 * inode pa tree 4806 */ 4807 goto try_group_pa; 4808 } 4809 } 4810 4811 BUG_ON(!(tmp_pa && tmp_pa->pa_lstart <= ac->ac_o_ex.fe_logical)); 4812 4813 /* 4814 * Step 3: If the left adjacent pa is deleted, keep moving left to find 4815 * the first non deleted adjacent pa. After this step we should have a 4816 * valid tmp_pa which is guaranteed to be non deleted. 4817 */ 4818 for (iter = &tmp_pa->pa_node.inode_node;; iter = rb_prev(iter)) { 4819 if (!iter) { 4820 /* 4821 * no non deleted left adjacent pa, so stop searching 4822 * inode pa tree 4823 */ 4824 goto try_group_pa; 4825 } 4826 tmp_pa = rb_entry(iter, struct ext4_prealloc_space, 4827 pa_node.inode_node); 4828 spin_lock(&tmp_pa->pa_lock); 4829 if (tmp_pa->pa_deleted == 0) { 4830 /* 4831 * We will keep holding the pa_lock from 4832 * this point on because we don't want group discard 4833 * to delete this pa underneath us. Since group 4834 * discard is anyways an ENOSPC operation it 4835 * should be okay for it to wait a few more cycles. 4836 */ 4837 break; 4838 } else { 4839 spin_unlock(&tmp_pa->pa_lock); 4840 } 4841 } 4842 4843 BUG_ON(!(tmp_pa && tmp_pa->pa_lstart <= ac->ac_o_ex.fe_logical)); 4844 BUG_ON(tmp_pa->pa_deleted == 1); 4845 4846 /* 4847 * Step 4: We now have the non deleted left adjacent pa. Only this 4848 * pa can possibly satisfy the request hence check if it overlaps 4849 * original logical start and stop searching if it doesn't. 4850 */ 4851 if (ac->ac_o_ex.fe_logical >= pa_logical_end(sbi, tmp_pa)) { 4852 spin_unlock(&tmp_pa->pa_lock); 4853 goto try_group_pa; 4854 } 4855 4856 /* non-extent files can't have physical blocks past 2^32 */ 4857 if (!(ext4_test_inode_flag(ac->ac_inode, EXT4_INODE_EXTENTS)) && 4858 (tmp_pa->pa_pstart + EXT4_C2B(sbi, tmp_pa->pa_len) > 4859 EXT4_MAX_BLOCK_FILE_PHYS)) { 4860 /* 4861 * Since PAs don't overlap, we won't find any other PA to 4862 * satisfy this. 4863 */ 4864 spin_unlock(&tmp_pa->pa_lock); 4865 goto try_group_pa; 4866 } 4867 4868 if (tmp_pa->pa_free && likely(ext4_mb_pa_goal_check(ac, tmp_pa))) { 4869 atomic_inc(&tmp_pa->pa_count); 4870 ext4_mb_use_inode_pa(ac, tmp_pa); 4871 spin_unlock(&tmp_pa->pa_lock); 4872 read_unlock(&ei->i_prealloc_lock); 4873 return true; 4874 } else { 4875 /* 4876 * We found a valid overlapping pa but couldn't use it because 4877 * it had no free blocks. This should ideally never happen 4878 * because: 4879 * 4880 * 1. When a new inode pa is added to rbtree it must have 4881 * pa_free > 0 since otherwise we won't actually need 4882 * preallocation. 4883 * 4884 * 2. An inode pa that is in the rbtree can only have it's 4885 * pa_free become zero when another thread calls: 4886 * ext4_mb_new_blocks 4887 * ext4_mb_use_preallocated 4888 * ext4_mb_use_inode_pa 4889 * 4890 * 3. Further, after the above calls make pa_free == 0, we will 4891 * immediately remove it from the rbtree in: 4892 * ext4_mb_new_blocks 4893 * ext4_mb_release_context 4894 * ext4_mb_put_pa 4895 * 4896 * 4. Since the pa_free becoming 0 and pa_free getting removed 4897 * from tree both happen in ext4_mb_new_blocks, which is always 4898 * called with i_data_sem held for data allocations, we can be 4899 * sure that another process will never see a pa in rbtree with 4900 * pa_free == 0. 4901 */ 4902 WARN_ON_ONCE(tmp_pa->pa_free == 0); 4903 } 4904 spin_unlock(&tmp_pa->pa_lock); 4905 try_group_pa: 4906 read_unlock(&ei->i_prealloc_lock); 4907 4908 /* can we use group allocation? */ 4909 if (!(ac->ac_flags & EXT4_MB_HINT_GROUP_ALLOC)) 4910 return false; 4911 4912 /* inode may have no locality group for some reason */ 4913 lg = ac->ac_lg; 4914 if (lg == NULL) 4915 return false; 4916 order = fls(ac->ac_o_ex.fe_len) - 1; 4917 if (order > PREALLOC_TB_SIZE - 1) 4918 /* The max size of hash table is PREALLOC_TB_SIZE */ 4919 order = PREALLOC_TB_SIZE - 1; 4920 4921 goal_block = ext4_grp_offs_to_block(ac->ac_sb, &ac->ac_g_ex); 4922 /* 4923 * search for the prealloc space that is having 4924 * minimal distance from the goal block. 4925 */ 4926 for (i = order; i < PREALLOC_TB_SIZE; i++) { 4927 rcu_read_lock(); 4928 list_for_each_entry_rcu(tmp_pa, &lg->lg_prealloc_list[i], 4929 pa_node.lg_list) { 4930 spin_lock(&tmp_pa->pa_lock); 4931 if (tmp_pa->pa_deleted == 0 && 4932 tmp_pa->pa_free >= ac->ac_o_ex.fe_len) { 4933 4934 cpa = ext4_mb_check_group_pa(goal_block, 4935 tmp_pa, cpa); 4936 } 4937 spin_unlock(&tmp_pa->pa_lock); 4938 } 4939 rcu_read_unlock(); 4940 } 4941 if (cpa) { 4942 ext4_mb_use_group_pa(ac, cpa); 4943 return true; 4944 } 4945 return false; 4946 } 4947 4948 /* 4949 * the function goes through all preallocation in this group and marks them 4950 * used in in-core bitmap. buddy must be generated from this bitmap 4951 * Need to be called with ext4 group lock held 4952 */ 4953 static noinline_for_stack 4954 void ext4_mb_generate_from_pa(struct super_block *sb, void *bitmap, 4955 ext4_group_t group) 4956 { 4957 struct ext4_group_info *grp = ext4_get_group_info(sb, group); 4958 struct ext4_prealloc_space *pa; 4959 struct list_head *cur; 4960 ext4_group_t groupnr; 4961 ext4_grpblk_t start; 4962 int preallocated = 0; 4963 int len; 4964 4965 if (!grp) 4966 return; 4967 4968 /* all form of preallocation discards first load group, 4969 * so the only competing code is preallocation use. 4970 * we don't need any locking here 4971 * notice we do NOT ignore preallocations with pa_deleted 4972 * otherwise we could leave used blocks available for 4973 * allocation in buddy when concurrent ext4_mb_put_pa() 4974 * is dropping preallocation 4975 */ 4976 list_for_each(cur, &grp->bb_prealloc_list) { 4977 pa = list_entry(cur, struct ext4_prealloc_space, pa_group_list); 4978 spin_lock(&pa->pa_lock); 4979 ext4_get_group_no_and_offset(sb, pa->pa_pstart, 4980 &groupnr, &start); 4981 len = pa->pa_len; 4982 spin_unlock(&pa->pa_lock); 4983 if (unlikely(len == 0)) 4984 continue; 4985 BUG_ON(groupnr != group); 4986 mb_set_bits(bitmap, start, len); 4987 preallocated += len; 4988 } 4989 mb_debug(sb, "preallocated %d for group %u\n", preallocated, group); 4990 } 4991 4992 static void ext4_mb_mark_pa_deleted(struct super_block *sb, 4993 struct ext4_prealloc_space *pa) 4994 { 4995 struct ext4_inode_info *ei; 4996 4997 if (pa->pa_deleted) { 4998 ext4_warning(sb, "deleted pa, type:%d, pblk:%llu, lblk:%u, len:%d\n", 4999 pa->pa_type, pa->pa_pstart, pa->pa_lstart, 5000 pa->pa_len); 5001 return; 5002 } 5003 5004 pa->pa_deleted = 1; 5005 5006 if (pa->pa_type == MB_INODE_PA) { 5007 ei = EXT4_I(pa->pa_inode); 5008 atomic_dec(&ei->i_prealloc_active); 5009 } 5010 } 5011 5012 static inline void ext4_mb_pa_free(struct ext4_prealloc_space *pa) 5013 { 5014 BUG_ON(!pa); 5015 BUG_ON(atomic_read(&pa->pa_count)); 5016 BUG_ON(pa->pa_deleted == 0); 5017 kmem_cache_free(ext4_pspace_cachep, pa); 5018 } 5019 5020 static void ext4_mb_pa_callback(struct rcu_head *head) 5021 { 5022 struct ext4_prealloc_space *pa; 5023 5024 pa = container_of(head, struct ext4_prealloc_space, u.pa_rcu); 5025 ext4_mb_pa_free(pa); 5026 } 5027 5028 /* 5029 * drops a reference to preallocated space descriptor 5030 * if this was the last reference and the space is consumed 5031 */ 5032 static void ext4_mb_put_pa(struct ext4_allocation_context *ac, 5033 struct super_block *sb, struct ext4_prealloc_space *pa) 5034 { 5035 ext4_group_t grp; 5036 ext4_fsblk_t grp_blk; 5037 struct ext4_inode_info *ei = EXT4_I(ac->ac_inode); 5038 5039 /* in this short window concurrent discard can set pa_deleted */ 5040 spin_lock(&pa->pa_lock); 5041 if (!atomic_dec_and_test(&pa->pa_count) || pa->pa_free != 0) { 5042 spin_unlock(&pa->pa_lock); 5043 return; 5044 } 5045 5046 if (pa->pa_deleted == 1) { 5047 spin_unlock(&pa->pa_lock); 5048 return; 5049 } 5050 5051 ext4_mb_mark_pa_deleted(sb, pa); 5052 spin_unlock(&pa->pa_lock); 5053 5054 grp_blk = pa->pa_pstart; 5055 /* 5056 * If doing group-based preallocation, pa_pstart may be in the 5057 * next group when pa is used up 5058 */ 5059 if (pa->pa_type == MB_GROUP_PA) 5060 grp_blk--; 5061 5062 grp = ext4_get_group_number(sb, grp_blk); 5063 5064 /* 5065 * possible race: 5066 * 5067 * P1 (buddy init) P2 (regular allocation) 5068 * find block B in PA 5069 * copy on-disk bitmap to buddy 5070 * mark B in on-disk bitmap 5071 * drop PA from group 5072 * mark all PAs in buddy 5073 * 5074 * thus, P1 initializes buddy with B available. to prevent this 5075 * we make "copy" and "mark all PAs" atomic and serialize "drop PA" 5076 * against that pair 5077 */ 5078 ext4_lock_group(sb, grp); 5079 list_del(&pa->pa_group_list); 5080 ext4_unlock_group(sb, grp); 5081 5082 if (pa->pa_type == MB_INODE_PA) { 5083 write_lock(pa->pa_node_lock.inode_lock); 5084 rb_erase(&pa->pa_node.inode_node, &ei->i_prealloc_node); 5085 write_unlock(pa->pa_node_lock.inode_lock); 5086 ext4_mb_pa_free(pa); 5087 } else { 5088 spin_lock(pa->pa_node_lock.lg_lock); 5089 list_del_rcu(&pa->pa_node.lg_list); 5090 spin_unlock(pa->pa_node_lock.lg_lock); 5091 call_rcu(&(pa)->u.pa_rcu, ext4_mb_pa_callback); 5092 } 5093 } 5094 5095 static void ext4_mb_pa_rb_insert(struct rb_root *root, struct rb_node *new) 5096 { 5097 struct rb_node **iter = &root->rb_node, *parent = NULL; 5098 struct ext4_prealloc_space *iter_pa, *new_pa; 5099 ext4_lblk_t iter_start, new_start; 5100 5101 while (*iter) { 5102 iter_pa = rb_entry(*iter, struct ext4_prealloc_space, 5103 pa_node.inode_node); 5104 new_pa = rb_entry(new, struct ext4_prealloc_space, 5105 pa_node.inode_node); 5106 iter_start = iter_pa->pa_lstart; 5107 new_start = new_pa->pa_lstart; 5108 5109 parent = *iter; 5110 if (new_start < iter_start) 5111 iter = &((*iter)->rb_left); 5112 else 5113 iter = &((*iter)->rb_right); 5114 } 5115 5116 rb_link_node(new, parent, iter); 5117 rb_insert_color(new, root); 5118 } 5119 5120 /* 5121 * creates new preallocated space for given inode 5122 */ 5123 static noinline_for_stack void 5124 ext4_mb_new_inode_pa(struct ext4_allocation_context *ac) 5125 { 5126 struct super_block *sb = ac->ac_sb; 5127 struct ext4_sb_info *sbi = EXT4_SB(sb); 5128 struct ext4_prealloc_space *pa; 5129 struct ext4_group_info *grp; 5130 struct ext4_inode_info *ei; 5131 5132 /* preallocate only when found space is larger then requested */ 5133 BUG_ON(ac->ac_o_ex.fe_len >= ac->ac_b_ex.fe_len); 5134 BUG_ON(ac->ac_status != AC_STATUS_FOUND); 5135 BUG_ON(!S_ISREG(ac->ac_inode->i_mode)); 5136 BUG_ON(ac->ac_pa == NULL); 5137 5138 pa = ac->ac_pa; 5139 5140 if (ac->ac_b_ex.fe_len < ac->ac_orig_goal_len) { 5141 struct ext4_free_extent ex = { 5142 .fe_logical = ac->ac_g_ex.fe_logical, 5143 .fe_len = ac->ac_orig_goal_len, 5144 }; 5145 loff_t orig_goal_end = extent_logical_end(sbi, &ex); 5146 5147 /* we can't allocate as much as normalizer wants. 5148 * so, found space must get proper lstart 5149 * to cover original request */ 5150 BUG_ON(ac->ac_g_ex.fe_logical > ac->ac_o_ex.fe_logical); 5151 BUG_ON(ac->ac_g_ex.fe_len < ac->ac_o_ex.fe_len); 5152 5153 /* 5154 * Use the below logic for adjusting best extent as it keeps 5155 * fragmentation in check while ensuring logical range of best 5156 * extent doesn't overflow out of goal extent: 5157 * 5158 * 1. Check if best ex can be kept at end of goal (before 5159 * cr_best_avail trimmed it) and still cover original start 5160 * 2. Else, check if best ex can be kept at start of goal and 5161 * still cover original start 5162 * 3. Else, keep the best ex at start of original request. 5163 */ 5164 ex.fe_len = ac->ac_b_ex.fe_len; 5165 5166 ex.fe_logical = orig_goal_end - EXT4_C2B(sbi, ex.fe_len); 5167 if (ac->ac_o_ex.fe_logical >= ex.fe_logical) 5168 goto adjust_bex; 5169 5170 ex.fe_logical = ac->ac_g_ex.fe_logical; 5171 if (ac->ac_o_ex.fe_logical < extent_logical_end(sbi, &ex)) 5172 goto adjust_bex; 5173 5174 ex.fe_logical = ac->ac_o_ex.fe_logical; 5175 adjust_bex: 5176 ac->ac_b_ex.fe_logical = ex.fe_logical; 5177 5178 BUG_ON(ac->ac_o_ex.fe_logical < ac->ac_b_ex.fe_logical); 5179 BUG_ON(ac->ac_o_ex.fe_len > ac->ac_b_ex.fe_len); 5180 BUG_ON(extent_logical_end(sbi, &ex) > orig_goal_end); 5181 } 5182 5183 pa->pa_lstart = ac->ac_b_ex.fe_logical; 5184 pa->pa_pstart = ext4_grp_offs_to_block(sb, &ac->ac_b_ex); 5185 pa->pa_len = ac->ac_b_ex.fe_len; 5186 pa->pa_free = pa->pa_len; 5187 spin_lock_init(&pa->pa_lock); 5188 INIT_LIST_HEAD(&pa->pa_group_list); 5189 pa->pa_deleted = 0; 5190 pa->pa_type = MB_INODE_PA; 5191 5192 mb_debug(sb, "new inode pa %p: %llu/%d for %u\n", pa, pa->pa_pstart, 5193 pa->pa_len, pa->pa_lstart); 5194 trace_ext4_mb_new_inode_pa(ac, pa); 5195 5196 atomic_add(pa->pa_free, &sbi->s_mb_preallocated); 5197 ext4_mb_use_inode_pa(ac, pa); 5198 5199 ei = EXT4_I(ac->ac_inode); 5200 grp = ext4_get_group_info(sb, ac->ac_b_ex.fe_group); 5201 if (!grp) 5202 return; 5203 5204 pa->pa_node_lock.inode_lock = &ei->i_prealloc_lock; 5205 pa->pa_inode = ac->ac_inode; 5206 5207 list_add(&pa->pa_group_list, &grp->bb_prealloc_list); 5208 5209 write_lock(pa->pa_node_lock.inode_lock); 5210 ext4_mb_pa_rb_insert(&ei->i_prealloc_node, &pa->pa_node.inode_node); 5211 write_unlock(pa->pa_node_lock.inode_lock); 5212 atomic_inc(&ei->i_prealloc_active); 5213 } 5214 5215 /* 5216 * creates new preallocated space for locality group inodes belongs to 5217 */ 5218 static noinline_for_stack void 5219 ext4_mb_new_group_pa(struct ext4_allocation_context *ac) 5220 { 5221 struct super_block *sb = ac->ac_sb; 5222 struct ext4_locality_group *lg; 5223 struct ext4_prealloc_space *pa; 5224 struct ext4_group_info *grp; 5225 5226 /* preallocate only when found space is larger then requested */ 5227 BUG_ON(ac->ac_o_ex.fe_len >= ac->ac_b_ex.fe_len); 5228 BUG_ON(ac->ac_status != AC_STATUS_FOUND); 5229 BUG_ON(!S_ISREG(ac->ac_inode->i_mode)); 5230 BUG_ON(ac->ac_pa == NULL); 5231 5232 pa = ac->ac_pa; 5233 5234 pa->pa_pstart = ext4_grp_offs_to_block(sb, &ac->ac_b_ex); 5235 pa->pa_lstart = pa->pa_pstart; 5236 pa->pa_len = ac->ac_b_ex.fe_len; 5237 pa->pa_free = pa->pa_len; 5238 spin_lock_init(&pa->pa_lock); 5239 INIT_LIST_HEAD(&pa->pa_node.lg_list); 5240 INIT_LIST_HEAD(&pa->pa_group_list); 5241 pa->pa_deleted = 0; 5242 pa->pa_type = MB_GROUP_PA; 5243 5244 mb_debug(sb, "new group pa %p: %llu/%d for %u\n", pa, pa->pa_pstart, 5245 pa->pa_len, pa->pa_lstart); 5246 trace_ext4_mb_new_group_pa(ac, pa); 5247 5248 ext4_mb_use_group_pa(ac, pa); 5249 atomic_add(pa->pa_free, &EXT4_SB(sb)->s_mb_preallocated); 5250 5251 grp = ext4_get_group_info(sb, ac->ac_b_ex.fe_group); 5252 if (!grp) 5253 return; 5254 lg = ac->ac_lg; 5255 BUG_ON(lg == NULL); 5256 5257 pa->pa_node_lock.lg_lock = &lg->lg_prealloc_lock; 5258 pa->pa_inode = NULL; 5259 5260 list_add(&pa->pa_group_list, &grp->bb_prealloc_list); 5261 5262 /* 5263 * We will later add the new pa to the right bucket 5264 * after updating the pa_free in ext4_mb_release_context 5265 */ 5266 } 5267 5268 static void ext4_mb_new_preallocation(struct ext4_allocation_context *ac) 5269 { 5270 if (ac->ac_flags & EXT4_MB_HINT_GROUP_ALLOC) 5271 ext4_mb_new_group_pa(ac); 5272 else 5273 ext4_mb_new_inode_pa(ac); 5274 } 5275 5276 /* 5277 * finds all unused blocks in on-disk bitmap, frees them in 5278 * in-core bitmap and buddy. 5279 * @pa must be unlinked from inode and group lists, so that 5280 * nobody else can find/use it. 5281 * the caller MUST hold group/inode locks. 5282 * TODO: optimize the case when there are no in-core structures yet 5283 */ 5284 static noinline_for_stack int 5285 ext4_mb_release_inode_pa(struct ext4_buddy *e4b, struct buffer_head *bitmap_bh, 5286 struct ext4_prealloc_space *pa) 5287 { 5288 struct super_block *sb = e4b->bd_sb; 5289 struct ext4_sb_info *sbi = EXT4_SB(sb); 5290 unsigned int end; 5291 unsigned int next; 5292 ext4_group_t group; 5293 ext4_grpblk_t bit; 5294 unsigned long long grp_blk_start; 5295 int free = 0; 5296 5297 BUG_ON(pa->pa_deleted == 0); 5298 ext4_get_group_no_and_offset(sb, pa->pa_pstart, &group, &bit); 5299 grp_blk_start = pa->pa_pstart - EXT4_C2B(sbi, bit); 5300 BUG_ON(group != e4b->bd_group && pa->pa_len != 0); 5301 end = bit + pa->pa_len; 5302 5303 while (bit < end) { 5304 bit = mb_find_next_zero_bit(bitmap_bh->b_data, end, bit); 5305 if (bit >= end) 5306 break; 5307 next = mb_find_next_bit(bitmap_bh->b_data, end, bit); 5308 mb_debug(sb, "free preallocated %u/%u in group %u\n", 5309 (unsigned) ext4_group_first_block_no(sb, group) + bit, 5310 (unsigned) next - bit, (unsigned) group); 5311 free += next - bit; 5312 5313 trace_ext4_mballoc_discard(sb, NULL, group, bit, next - bit); 5314 trace_ext4_mb_release_inode_pa(pa, (grp_blk_start + 5315 EXT4_C2B(sbi, bit)), 5316 next - bit); 5317 mb_free_blocks(pa->pa_inode, e4b, bit, next - bit); 5318 bit = next + 1; 5319 } 5320 if (free != pa->pa_free) { 5321 ext4_msg(e4b->bd_sb, KERN_CRIT, 5322 "pa %p: logic %lu, phys. %lu, len %d", 5323 pa, (unsigned long) pa->pa_lstart, 5324 (unsigned long) pa->pa_pstart, 5325 pa->pa_len); 5326 ext4_grp_locked_error(sb, group, 0, 0, "free %u, pa_free %u", 5327 free, pa->pa_free); 5328 /* 5329 * pa is already deleted so we use the value obtained 5330 * from the bitmap and continue. 5331 */ 5332 } 5333 atomic_add(free, &sbi->s_mb_discarded); 5334 5335 return 0; 5336 } 5337 5338 static noinline_for_stack int 5339 ext4_mb_release_group_pa(struct ext4_buddy *e4b, 5340 struct ext4_prealloc_space *pa) 5341 { 5342 struct super_block *sb = e4b->bd_sb; 5343 ext4_group_t group; 5344 ext4_grpblk_t bit; 5345 5346 trace_ext4_mb_release_group_pa(sb, pa); 5347 BUG_ON(pa->pa_deleted == 0); 5348 ext4_get_group_no_and_offset(sb, pa->pa_pstart, &group, &bit); 5349 if (unlikely(group != e4b->bd_group && pa->pa_len != 0)) { 5350 ext4_warning(sb, "bad group: expected %u, group %u, pa_start %llu", 5351 e4b->bd_group, group, pa->pa_pstart); 5352 return 0; 5353 } 5354 mb_free_blocks(pa->pa_inode, e4b, bit, pa->pa_len); 5355 atomic_add(pa->pa_len, &EXT4_SB(sb)->s_mb_discarded); 5356 trace_ext4_mballoc_discard(sb, NULL, group, bit, pa->pa_len); 5357 5358 return 0; 5359 } 5360 5361 /* 5362 * releases all preallocations in given group 5363 * 5364 * first, we need to decide discard policy: 5365 * - when do we discard 5366 * 1) ENOSPC 5367 * - how many do we discard 5368 * 1) how many requested 5369 */ 5370 static noinline_for_stack int 5371 ext4_mb_discard_group_preallocations(struct super_block *sb, 5372 ext4_group_t group, int *busy) 5373 { 5374 struct ext4_group_info *grp = ext4_get_group_info(sb, group); 5375 struct buffer_head *bitmap_bh = NULL; 5376 struct ext4_prealloc_space *pa, *tmp; 5377 LIST_HEAD(list); 5378 struct ext4_buddy e4b; 5379 struct ext4_inode_info *ei; 5380 int err; 5381 int free = 0; 5382 5383 if (!grp) 5384 return 0; 5385 mb_debug(sb, "discard preallocation for group %u\n", group); 5386 if (list_empty(&grp->bb_prealloc_list)) 5387 goto out_dbg; 5388 5389 bitmap_bh = ext4_read_block_bitmap(sb, group); 5390 if (IS_ERR(bitmap_bh)) { 5391 err = PTR_ERR(bitmap_bh); 5392 ext4_error_err(sb, -err, 5393 "Error %d reading block bitmap for %u", 5394 err, group); 5395 goto out_dbg; 5396 } 5397 5398 err = ext4_mb_load_buddy(sb, group, &e4b); 5399 if (err) { 5400 ext4_warning(sb, "Error %d loading buddy information for %u", 5401 err, group); 5402 put_bh(bitmap_bh); 5403 goto out_dbg; 5404 } 5405 5406 ext4_lock_group(sb, group); 5407 list_for_each_entry_safe(pa, tmp, 5408 &grp->bb_prealloc_list, pa_group_list) { 5409 spin_lock(&pa->pa_lock); 5410 if (atomic_read(&pa->pa_count)) { 5411 spin_unlock(&pa->pa_lock); 5412 *busy = 1; 5413 continue; 5414 } 5415 if (pa->pa_deleted) { 5416 spin_unlock(&pa->pa_lock); 5417 continue; 5418 } 5419 5420 /* seems this one can be freed ... */ 5421 ext4_mb_mark_pa_deleted(sb, pa); 5422 5423 if (!free) 5424 this_cpu_inc(discard_pa_seq); 5425 5426 /* we can trust pa_free ... */ 5427 free += pa->pa_free; 5428 5429 spin_unlock(&pa->pa_lock); 5430 5431 list_del(&pa->pa_group_list); 5432 list_add(&pa->u.pa_tmp_list, &list); 5433 } 5434 5435 /* now free all selected PAs */ 5436 list_for_each_entry_safe(pa, tmp, &list, u.pa_tmp_list) { 5437 5438 /* remove from object (inode or locality group) */ 5439 if (pa->pa_type == MB_GROUP_PA) { 5440 spin_lock(pa->pa_node_lock.lg_lock); 5441 list_del_rcu(&pa->pa_node.lg_list); 5442 spin_unlock(pa->pa_node_lock.lg_lock); 5443 } else { 5444 write_lock(pa->pa_node_lock.inode_lock); 5445 ei = EXT4_I(pa->pa_inode); 5446 rb_erase(&pa->pa_node.inode_node, &ei->i_prealloc_node); 5447 write_unlock(pa->pa_node_lock.inode_lock); 5448 } 5449 5450 list_del(&pa->u.pa_tmp_list); 5451 5452 if (pa->pa_type == MB_GROUP_PA) { 5453 ext4_mb_release_group_pa(&e4b, pa); 5454 call_rcu(&(pa)->u.pa_rcu, ext4_mb_pa_callback); 5455 } else { 5456 ext4_mb_release_inode_pa(&e4b, bitmap_bh, pa); 5457 ext4_mb_pa_free(pa); 5458 } 5459 } 5460 5461 ext4_unlock_group(sb, group); 5462 ext4_mb_unload_buddy(&e4b); 5463 put_bh(bitmap_bh); 5464 out_dbg: 5465 mb_debug(sb, "discarded (%d) blocks preallocated for group %u bb_free (%d)\n", 5466 free, group, grp->bb_free); 5467 return free; 5468 } 5469 5470 /* 5471 * releases all non-used preallocated blocks for given inode 5472 * 5473 * It's important to discard preallocations under i_data_sem 5474 * We don't want another block to be served from the prealloc 5475 * space when we are discarding the inode prealloc space. 5476 * 5477 * FIXME!! Make sure it is valid at all the call sites 5478 */ 5479 void ext4_discard_preallocations(struct inode *inode, unsigned int needed) 5480 { 5481 struct ext4_inode_info *ei = EXT4_I(inode); 5482 struct super_block *sb = inode->i_sb; 5483 struct buffer_head *bitmap_bh = NULL; 5484 struct ext4_prealloc_space *pa, *tmp; 5485 ext4_group_t group = 0; 5486 LIST_HEAD(list); 5487 struct ext4_buddy e4b; 5488 struct rb_node *iter; 5489 int err; 5490 5491 if (!S_ISREG(inode->i_mode)) { 5492 return; 5493 } 5494 5495 if (EXT4_SB(sb)->s_mount_state & EXT4_FC_REPLAY) 5496 return; 5497 5498 mb_debug(sb, "discard preallocation for inode %lu\n", 5499 inode->i_ino); 5500 trace_ext4_discard_preallocations(inode, 5501 atomic_read(&ei->i_prealloc_active), needed); 5502 5503 if (needed == 0) 5504 needed = UINT_MAX; 5505 5506 repeat: 5507 /* first, collect all pa's in the inode */ 5508 write_lock(&ei->i_prealloc_lock); 5509 for (iter = rb_first(&ei->i_prealloc_node); iter && needed; 5510 iter = rb_next(iter)) { 5511 pa = rb_entry(iter, struct ext4_prealloc_space, 5512 pa_node.inode_node); 5513 BUG_ON(pa->pa_node_lock.inode_lock != &ei->i_prealloc_lock); 5514 5515 spin_lock(&pa->pa_lock); 5516 if (atomic_read(&pa->pa_count)) { 5517 /* this shouldn't happen often - nobody should 5518 * use preallocation while we're discarding it */ 5519 spin_unlock(&pa->pa_lock); 5520 write_unlock(&ei->i_prealloc_lock); 5521 ext4_msg(sb, KERN_ERR, 5522 "uh-oh! used pa while discarding"); 5523 WARN_ON(1); 5524 schedule_timeout_uninterruptible(HZ); 5525 goto repeat; 5526 5527 } 5528 if (pa->pa_deleted == 0) { 5529 ext4_mb_mark_pa_deleted(sb, pa); 5530 spin_unlock(&pa->pa_lock); 5531 rb_erase(&pa->pa_node.inode_node, &ei->i_prealloc_node); 5532 list_add(&pa->u.pa_tmp_list, &list); 5533 needed--; 5534 continue; 5535 } 5536 5537 /* someone is deleting pa right now */ 5538 spin_unlock(&pa->pa_lock); 5539 write_unlock(&ei->i_prealloc_lock); 5540 5541 /* we have to wait here because pa_deleted 5542 * doesn't mean pa is already unlinked from 5543 * the list. as we might be called from 5544 * ->clear_inode() the inode will get freed 5545 * and concurrent thread which is unlinking 5546 * pa from inode's list may access already 5547 * freed memory, bad-bad-bad */ 5548 5549 /* XXX: if this happens too often, we can 5550 * add a flag to force wait only in case 5551 * of ->clear_inode(), but not in case of 5552 * regular truncate */ 5553 schedule_timeout_uninterruptible(HZ); 5554 goto repeat; 5555 } 5556 write_unlock(&ei->i_prealloc_lock); 5557 5558 list_for_each_entry_safe(pa, tmp, &list, u.pa_tmp_list) { 5559 BUG_ON(pa->pa_type != MB_INODE_PA); 5560 group = ext4_get_group_number(sb, pa->pa_pstart); 5561 5562 err = ext4_mb_load_buddy_gfp(sb, group, &e4b, 5563 GFP_NOFS|__GFP_NOFAIL); 5564 if (err) { 5565 ext4_error_err(sb, -err, "Error %d loading buddy information for %u", 5566 err, group); 5567 continue; 5568 } 5569 5570 bitmap_bh = ext4_read_block_bitmap(sb, group); 5571 if (IS_ERR(bitmap_bh)) { 5572 err = PTR_ERR(bitmap_bh); 5573 ext4_error_err(sb, -err, "Error %d reading block bitmap for %u", 5574 err, group); 5575 ext4_mb_unload_buddy(&e4b); 5576 continue; 5577 } 5578 5579 ext4_lock_group(sb, group); 5580 list_del(&pa->pa_group_list); 5581 ext4_mb_release_inode_pa(&e4b, bitmap_bh, pa); 5582 ext4_unlock_group(sb, group); 5583 5584 ext4_mb_unload_buddy(&e4b); 5585 put_bh(bitmap_bh); 5586 5587 list_del(&pa->u.pa_tmp_list); 5588 ext4_mb_pa_free(pa); 5589 } 5590 } 5591 5592 static int ext4_mb_pa_alloc(struct ext4_allocation_context *ac) 5593 { 5594 struct ext4_prealloc_space *pa; 5595 5596 BUG_ON(ext4_pspace_cachep == NULL); 5597 pa = kmem_cache_zalloc(ext4_pspace_cachep, GFP_NOFS); 5598 if (!pa) 5599 return -ENOMEM; 5600 atomic_set(&pa->pa_count, 1); 5601 ac->ac_pa = pa; 5602 return 0; 5603 } 5604 5605 static void ext4_mb_pa_put_free(struct ext4_allocation_context *ac) 5606 { 5607 struct ext4_prealloc_space *pa = ac->ac_pa; 5608 5609 BUG_ON(!pa); 5610 ac->ac_pa = NULL; 5611 WARN_ON(!atomic_dec_and_test(&pa->pa_count)); 5612 /* 5613 * current function is only called due to an error or due to 5614 * len of found blocks < len of requested blocks hence the PA has not 5615 * been added to grp->bb_prealloc_list. So we don't need to lock it 5616 */ 5617 pa->pa_deleted = 1; 5618 ext4_mb_pa_free(pa); 5619 } 5620 5621 #ifdef CONFIG_EXT4_DEBUG 5622 static inline void ext4_mb_show_pa(struct super_block *sb) 5623 { 5624 ext4_group_t i, ngroups; 5625 5626 if (ext4_forced_shutdown(sb)) 5627 return; 5628 5629 ngroups = ext4_get_groups_count(sb); 5630 mb_debug(sb, "groups: "); 5631 for (i = 0; i < ngroups; i++) { 5632 struct ext4_group_info *grp = ext4_get_group_info(sb, i); 5633 struct ext4_prealloc_space *pa; 5634 ext4_grpblk_t start; 5635 struct list_head *cur; 5636 5637 if (!grp) 5638 continue; 5639 ext4_lock_group(sb, i); 5640 list_for_each(cur, &grp->bb_prealloc_list) { 5641 pa = list_entry(cur, struct ext4_prealloc_space, 5642 pa_group_list); 5643 spin_lock(&pa->pa_lock); 5644 ext4_get_group_no_and_offset(sb, pa->pa_pstart, 5645 NULL, &start); 5646 spin_unlock(&pa->pa_lock); 5647 mb_debug(sb, "PA:%u:%d:%d\n", i, start, 5648 pa->pa_len); 5649 } 5650 ext4_unlock_group(sb, i); 5651 mb_debug(sb, "%u: %d/%d\n", i, grp->bb_free, 5652 grp->bb_fragments); 5653 } 5654 } 5655 5656 static void ext4_mb_show_ac(struct ext4_allocation_context *ac) 5657 { 5658 struct super_block *sb = ac->ac_sb; 5659 5660 if (ext4_forced_shutdown(sb)) 5661 return; 5662 5663 mb_debug(sb, "Can't allocate:" 5664 " Allocation context details:"); 5665 mb_debug(sb, "status %u flags 0x%x", 5666 ac->ac_status, ac->ac_flags); 5667 mb_debug(sb, "orig %lu/%lu/%lu@%lu, " 5668 "goal %lu/%lu/%lu@%lu, " 5669 "best %lu/%lu/%lu@%lu cr %d", 5670 (unsigned long)ac->ac_o_ex.fe_group, 5671 (unsigned long)ac->ac_o_ex.fe_start, 5672 (unsigned long)ac->ac_o_ex.fe_len, 5673 (unsigned long)ac->ac_o_ex.fe_logical, 5674 (unsigned long)ac->ac_g_ex.fe_group, 5675 (unsigned long)ac->ac_g_ex.fe_start, 5676 (unsigned long)ac->ac_g_ex.fe_len, 5677 (unsigned long)ac->ac_g_ex.fe_logical, 5678 (unsigned long)ac->ac_b_ex.fe_group, 5679 (unsigned long)ac->ac_b_ex.fe_start, 5680 (unsigned long)ac->ac_b_ex.fe_len, 5681 (unsigned long)ac->ac_b_ex.fe_logical, 5682 (int)ac->ac_criteria); 5683 mb_debug(sb, "%u found", ac->ac_found); 5684 mb_debug(sb, "used pa: %s, ", ac->ac_pa ? "yes" : "no"); 5685 if (ac->ac_pa) 5686 mb_debug(sb, "pa_type %s\n", ac->ac_pa->pa_type == MB_GROUP_PA ? 5687 "group pa" : "inode pa"); 5688 ext4_mb_show_pa(sb); 5689 } 5690 #else 5691 static inline void ext4_mb_show_pa(struct super_block *sb) 5692 { 5693 } 5694 static inline void ext4_mb_show_ac(struct ext4_allocation_context *ac) 5695 { 5696 ext4_mb_show_pa(ac->ac_sb); 5697 } 5698 #endif 5699 5700 /* 5701 * We use locality group preallocation for small size file. The size of the 5702 * file is determined by the current size or the resulting size after 5703 * allocation which ever is larger 5704 * 5705 * One can tune this size via /sys/fs/ext4/<partition>/mb_stream_req 5706 */ 5707 static void ext4_mb_group_or_file(struct ext4_allocation_context *ac) 5708 { 5709 struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb); 5710 int bsbits = ac->ac_sb->s_blocksize_bits; 5711 loff_t size, isize; 5712 bool inode_pa_eligible, group_pa_eligible; 5713 5714 if (!(ac->ac_flags & EXT4_MB_HINT_DATA)) 5715 return; 5716 5717 if (unlikely(ac->ac_flags & EXT4_MB_HINT_GOAL_ONLY)) 5718 return; 5719 5720 group_pa_eligible = sbi->s_mb_group_prealloc > 0; 5721 inode_pa_eligible = true; 5722 size = extent_logical_end(sbi, &ac->ac_o_ex); 5723 isize = (i_size_read(ac->ac_inode) + ac->ac_sb->s_blocksize - 1) 5724 >> bsbits; 5725 5726 /* No point in using inode preallocation for closed files */ 5727 if ((size == isize) && !ext4_fs_is_busy(sbi) && 5728 !inode_is_open_for_write(ac->ac_inode)) 5729 inode_pa_eligible = false; 5730 5731 size = max(size, isize); 5732 /* Don't use group allocation for large files */ 5733 if (size > sbi->s_mb_stream_request) 5734 group_pa_eligible = false; 5735 5736 if (!group_pa_eligible) { 5737 if (inode_pa_eligible) 5738 ac->ac_flags |= EXT4_MB_STREAM_ALLOC; 5739 else 5740 ac->ac_flags |= EXT4_MB_HINT_NOPREALLOC; 5741 return; 5742 } 5743 5744 BUG_ON(ac->ac_lg != NULL); 5745 /* 5746 * locality group prealloc space are per cpu. The reason for having 5747 * per cpu locality group is to reduce the contention between block 5748 * request from multiple CPUs. 5749 */ 5750 ac->ac_lg = raw_cpu_ptr(sbi->s_locality_groups); 5751 5752 /* we're going to use group allocation */ 5753 ac->ac_flags |= EXT4_MB_HINT_GROUP_ALLOC; 5754 5755 /* serialize all allocations in the group */ 5756 mutex_lock(&ac->ac_lg->lg_mutex); 5757 } 5758 5759 static noinline_for_stack void 5760 ext4_mb_initialize_context(struct ext4_allocation_context *ac, 5761 struct ext4_allocation_request *ar) 5762 { 5763 struct super_block *sb = ar->inode->i_sb; 5764 struct ext4_sb_info *sbi = EXT4_SB(sb); 5765 struct ext4_super_block *es = sbi->s_es; 5766 ext4_group_t group; 5767 unsigned int len; 5768 ext4_fsblk_t goal; 5769 ext4_grpblk_t block; 5770 5771 /* we can't allocate > group size */ 5772 len = ar->len; 5773 5774 /* just a dirty hack to filter too big requests */ 5775 if (len >= EXT4_CLUSTERS_PER_GROUP(sb)) 5776 len = EXT4_CLUSTERS_PER_GROUP(sb); 5777 5778 /* start searching from the goal */ 5779 goal = ar->goal; 5780 if (goal < le32_to_cpu(es->s_first_data_block) || 5781 goal >= ext4_blocks_count(es)) 5782 goal = le32_to_cpu(es->s_first_data_block); 5783 ext4_get_group_no_and_offset(sb, goal, &group, &block); 5784 5785 /* set up allocation goals */ 5786 ac->ac_b_ex.fe_logical = EXT4_LBLK_CMASK(sbi, ar->logical); 5787 ac->ac_status = AC_STATUS_CONTINUE; 5788 ac->ac_sb = sb; 5789 ac->ac_inode = ar->inode; 5790 ac->ac_o_ex.fe_logical = ac->ac_b_ex.fe_logical; 5791 ac->ac_o_ex.fe_group = group; 5792 ac->ac_o_ex.fe_start = block; 5793 ac->ac_o_ex.fe_len = len; 5794 ac->ac_g_ex = ac->ac_o_ex; 5795 ac->ac_orig_goal_len = ac->ac_g_ex.fe_len; 5796 ac->ac_flags = ar->flags; 5797 5798 /* we have to define context: we'll work with a file or 5799 * locality group. this is a policy, actually */ 5800 ext4_mb_group_or_file(ac); 5801 5802 mb_debug(sb, "init ac: %u blocks @ %u, goal %u, flags 0x%x, 2^%d, " 5803 "left: %u/%u, right %u/%u to %swritable\n", 5804 (unsigned) ar->len, (unsigned) ar->logical, 5805 (unsigned) ar->goal, ac->ac_flags, ac->ac_2order, 5806 (unsigned) ar->lleft, (unsigned) ar->pleft, 5807 (unsigned) ar->lright, (unsigned) ar->pright, 5808 inode_is_open_for_write(ar->inode) ? "" : "non-"); 5809 } 5810 5811 static noinline_for_stack void 5812 ext4_mb_discard_lg_preallocations(struct super_block *sb, 5813 struct ext4_locality_group *lg, 5814 int order, int total_entries) 5815 { 5816 ext4_group_t group = 0; 5817 struct ext4_buddy e4b; 5818 LIST_HEAD(discard_list); 5819 struct ext4_prealloc_space *pa, *tmp; 5820 5821 mb_debug(sb, "discard locality group preallocation\n"); 5822 5823 spin_lock(&lg->lg_prealloc_lock); 5824 list_for_each_entry_rcu(pa, &lg->lg_prealloc_list[order], 5825 pa_node.lg_list, 5826 lockdep_is_held(&lg->lg_prealloc_lock)) { 5827 spin_lock(&pa->pa_lock); 5828 if (atomic_read(&pa->pa_count)) { 5829 /* 5830 * This is the pa that we just used 5831 * for block allocation. So don't 5832 * free that 5833 */ 5834 spin_unlock(&pa->pa_lock); 5835 continue; 5836 } 5837 if (pa->pa_deleted) { 5838 spin_unlock(&pa->pa_lock); 5839 continue; 5840 } 5841 /* only lg prealloc space */ 5842 BUG_ON(pa->pa_type != MB_GROUP_PA); 5843 5844 /* seems this one can be freed ... */ 5845 ext4_mb_mark_pa_deleted(sb, pa); 5846 spin_unlock(&pa->pa_lock); 5847 5848 list_del_rcu(&pa->pa_node.lg_list); 5849 list_add(&pa->u.pa_tmp_list, &discard_list); 5850 5851 total_entries--; 5852 if (total_entries <= 5) { 5853 /* 5854 * we want to keep only 5 entries 5855 * allowing it to grow to 8. This 5856 * mak sure we don't call discard 5857 * soon for this list. 5858 */ 5859 break; 5860 } 5861 } 5862 spin_unlock(&lg->lg_prealloc_lock); 5863 5864 list_for_each_entry_safe(pa, tmp, &discard_list, u.pa_tmp_list) { 5865 int err; 5866 5867 group = ext4_get_group_number(sb, pa->pa_pstart); 5868 err = ext4_mb_load_buddy_gfp(sb, group, &e4b, 5869 GFP_NOFS|__GFP_NOFAIL); 5870 if (err) { 5871 ext4_error_err(sb, -err, "Error %d loading buddy information for %u", 5872 err, group); 5873 continue; 5874 } 5875 ext4_lock_group(sb, group); 5876 list_del(&pa->pa_group_list); 5877 ext4_mb_release_group_pa(&e4b, pa); 5878 ext4_unlock_group(sb, group); 5879 5880 ext4_mb_unload_buddy(&e4b); 5881 list_del(&pa->u.pa_tmp_list); 5882 call_rcu(&(pa)->u.pa_rcu, ext4_mb_pa_callback); 5883 } 5884 } 5885 5886 /* 5887 * We have incremented pa_count. So it cannot be freed at this 5888 * point. Also we hold lg_mutex. So no parallel allocation is 5889 * possible from this lg. That means pa_free cannot be updated. 5890 * 5891 * A parallel ext4_mb_discard_group_preallocations is possible. 5892 * which can cause the lg_prealloc_list to be updated. 5893 */ 5894 5895 static void ext4_mb_add_n_trim(struct ext4_allocation_context *ac) 5896 { 5897 int order, added = 0, lg_prealloc_count = 1; 5898 struct super_block *sb = ac->ac_sb; 5899 struct ext4_locality_group *lg = ac->ac_lg; 5900 struct ext4_prealloc_space *tmp_pa, *pa = ac->ac_pa; 5901 5902 order = fls(pa->pa_free) - 1; 5903 if (order > PREALLOC_TB_SIZE - 1) 5904 /* The max size of hash table is PREALLOC_TB_SIZE */ 5905 order = PREALLOC_TB_SIZE - 1; 5906 /* Add the prealloc space to lg */ 5907 spin_lock(&lg->lg_prealloc_lock); 5908 list_for_each_entry_rcu(tmp_pa, &lg->lg_prealloc_list[order], 5909 pa_node.lg_list, 5910 lockdep_is_held(&lg->lg_prealloc_lock)) { 5911 spin_lock(&tmp_pa->pa_lock); 5912 if (tmp_pa->pa_deleted) { 5913 spin_unlock(&tmp_pa->pa_lock); 5914 continue; 5915 } 5916 if (!added && pa->pa_free < tmp_pa->pa_free) { 5917 /* Add to the tail of the previous entry */ 5918 list_add_tail_rcu(&pa->pa_node.lg_list, 5919 &tmp_pa->pa_node.lg_list); 5920 added = 1; 5921 /* 5922 * we want to count the total 5923 * number of entries in the list 5924 */ 5925 } 5926 spin_unlock(&tmp_pa->pa_lock); 5927 lg_prealloc_count++; 5928 } 5929 if (!added) 5930 list_add_tail_rcu(&pa->pa_node.lg_list, 5931 &lg->lg_prealloc_list[order]); 5932 spin_unlock(&lg->lg_prealloc_lock); 5933 5934 /* Now trim the list to be not more than 8 elements */ 5935 if (lg_prealloc_count > 8) 5936 ext4_mb_discard_lg_preallocations(sb, lg, 5937 order, lg_prealloc_count); 5938 } 5939 5940 /* 5941 * release all resource we used in allocation 5942 */ 5943 static int ext4_mb_release_context(struct ext4_allocation_context *ac) 5944 { 5945 struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb); 5946 struct ext4_prealloc_space *pa = ac->ac_pa; 5947 if (pa) { 5948 if (pa->pa_type == MB_GROUP_PA) { 5949 /* see comment in ext4_mb_use_group_pa() */ 5950 spin_lock(&pa->pa_lock); 5951 pa->pa_pstart += EXT4_C2B(sbi, ac->ac_b_ex.fe_len); 5952 pa->pa_lstart += EXT4_C2B(sbi, ac->ac_b_ex.fe_len); 5953 pa->pa_free -= ac->ac_b_ex.fe_len; 5954 pa->pa_len -= ac->ac_b_ex.fe_len; 5955 spin_unlock(&pa->pa_lock); 5956 5957 /* 5958 * We want to add the pa to the right bucket. 5959 * Remove it from the list and while adding 5960 * make sure the list to which we are adding 5961 * doesn't grow big. 5962 */ 5963 if (likely(pa->pa_free)) { 5964 spin_lock(pa->pa_node_lock.lg_lock); 5965 list_del_rcu(&pa->pa_node.lg_list); 5966 spin_unlock(pa->pa_node_lock.lg_lock); 5967 ext4_mb_add_n_trim(ac); 5968 } 5969 } 5970 5971 ext4_mb_put_pa(ac, ac->ac_sb, pa); 5972 } 5973 if (ac->ac_bitmap_page) 5974 put_page(ac->ac_bitmap_page); 5975 if (ac->ac_buddy_page) 5976 put_page(ac->ac_buddy_page); 5977 if (ac->ac_flags & EXT4_MB_HINT_GROUP_ALLOC) 5978 mutex_unlock(&ac->ac_lg->lg_mutex); 5979 ext4_mb_collect_stats(ac); 5980 return 0; 5981 } 5982 5983 static int ext4_mb_discard_preallocations(struct super_block *sb, int needed) 5984 { 5985 ext4_group_t i, ngroups = ext4_get_groups_count(sb); 5986 int ret; 5987 int freed = 0, busy = 0; 5988 int retry = 0; 5989 5990 trace_ext4_mb_discard_preallocations(sb, needed); 5991 5992 if (needed == 0) 5993 needed = EXT4_CLUSTERS_PER_GROUP(sb) + 1; 5994 repeat: 5995 for (i = 0; i < ngroups && needed > 0; i++) { 5996 ret = ext4_mb_discard_group_preallocations(sb, i, &busy); 5997 freed += ret; 5998 needed -= ret; 5999 cond_resched(); 6000 } 6001 6002 if (needed > 0 && busy && ++retry < 3) { 6003 busy = 0; 6004 goto repeat; 6005 } 6006 6007 return freed; 6008 } 6009 6010 static bool ext4_mb_discard_preallocations_should_retry(struct super_block *sb, 6011 struct ext4_allocation_context *ac, u64 *seq) 6012 { 6013 int freed; 6014 u64 seq_retry = 0; 6015 bool ret = false; 6016 6017 freed = ext4_mb_discard_preallocations(sb, ac->ac_o_ex.fe_len); 6018 if (freed) { 6019 ret = true; 6020 goto out_dbg; 6021 } 6022 seq_retry = ext4_get_discard_pa_seq_sum(); 6023 if (!(ac->ac_flags & EXT4_MB_STRICT_CHECK) || seq_retry != *seq) { 6024 ac->ac_flags |= EXT4_MB_STRICT_CHECK; 6025 *seq = seq_retry; 6026 ret = true; 6027 } 6028 6029 out_dbg: 6030 mb_debug(sb, "freed %d, retry ? %s\n", freed, ret ? "yes" : "no"); 6031 return ret; 6032 } 6033 6034 /* 6035 * Simple allocator for Ext4 fast commit replay path. It searches for blocks 6036 * linearly starting at the goal block and also excludes the blocks which 6037 * are going to be in use after fast commit replay. 6038 */ 6039 static ext4_fsblk_t 6040 ext4_mb_new_blocks_simple(struct ext4_allocation_request *ar, int *errp) 6041 { 6042 struct buffer_head *bitmap_bh; 6043 struct super_block *sb = ar->inode->i_sb; 6044 struct ext4_sb_info *sbi = EXT4_SB(sb); 6045 ext4_group_t group, nr; 6046 ext4_grpblk_t blkoff; 6047 ext4_grpblk_t max = EXT4_CLUSTERS_PER_GROUP(sb); 6048 ext4_grpblk_t i = 0; 6049 ext4_fsblk_t goal, block; 6050 struct ext4_super_block *es = sbi->s_es; 6051 6052 goal = ar->goal; 6053 if (goal < le32_to_cpu(es->s_first_data_block) || 6054 goal >= ext4_blocks_count(es)) 6055 goal = le32_to_cpu(es->s_first_data_block); 6056 6057 ar->len = 0; 6058 ext4_get_group_no_and_offset(sb, goal, &group, &blkoff); 6059 for (nr = ext4_get_groups_count(sb); nr > 0; nr--) { 6060 bitmap_bh = ext4_read_block_bitmap(sb, group); 6061 if (IS_ERR(bitmap_bh)) { 6062 *errp = PTR_ERR(bitmap_bh); 6063 pr_warn("Failed to read block bitmap\n"); 6064 return 0; 6065 } 6066 6067 while (1) { 6068 i = mb_find_next_zero_bit(bitmap_bh->b_data, max, 6069 blkoff); 6070 if (i >= max) 6071 break; 6072 if (ext4_fc_replay_check_excluded(sb, 6073 ext4_group_first_block_no(sb, group) + 6074 EXT4_C2B(sbi, i))) { 6075 blkoff = i + 1; 6076 } else 6077 break; 6078 } 6079 brelse(bitmap_bh); 6080 if (i < max) 6081 break; 6082 6083 if (++group >= ext4_get_groups_count(sb)) 6084 group = 0; 6085 6086 blkoff = 0; 6087 } 6088 6089 if (i >= max) { 6090 *errp = -ENOSPC; 6091 return 0; 6092 } 6093 6094 block = ext4_group_first_block_no(sb, group) + EXT4_C2B(sbi, i); 6095 ext4_mb_mark_bb(sb, block, 1, true); 6096 ar->len = 1; 6097 6098 return block; 6099 } 6100 6101 /* 6102 * Main entry point into mballoc to allocate blocks 6103 * it tries to use preallocation first, then falls back 6104 * to usual allocation 6105 */ 6106 ext4_fsblk_t ext4_mb_new_blocks(handle_t *handle, 6107 struct ext4_allocation_request *ar, int *errp) 6108 { 6109 struct ext4_allocation_context *ac = NULL; 6110 struct ext4_sb_info *sbi; 6111 struct super_block *sb; 6112 ext4_fsblk_t block = 0; 6113 unsigned int inquota = 0; 6114 unsigned int reserv_clstrs = 0; 6115 int retries = 0; 6116 u64 seq; 6117 6118 might_sleep(); 6119 sb = ar->inode->i_sb; 6120 sbi = EXT4_SB(sb); 6121 6122 trace_ext4_request_blocks(ar); 6123 if (sbi->s_mount_state & EXT4_FC_REPLAY) 6124 return ext4_mb_new_blocks_simple(ar, errp); 6125 6126 /* Allow to use superuser reservation for quota file */ 6127 if (ext4_is_quota_file(ar->inode)) 6128 ar->flags |= EXT4_MB_USE_ROOT_BLOCKS; 6129 6130 if ((ar->flags & EXT4_MB_DELALLOC_RESERVED) == 0) { 6131 /* Without delayed allocation we need to verify 6132 * there is enough free blocks to do block allocation 6133 * and verify allocation doesn't exceed the quota limits. 6134 */ 6135 while (ar->len && 6136 ext4_claim_free_clusters(sbi, ar->len, ar->flags)) { 6137 6138 /* let others to free the space */ 6139 cond_resched(); 6140 ar->len = ar->len >> 1; 6141 } 6142 if (!ar->len) { 6143 ext4_mb_show_pa(sb); 6144 *errp = -ENOSPC; 6145 return 0; 6146 } 6147 reserv_clstrs = ar->len; 6148 if (ar->flags & EXT4_MB_USE_ROOT_BLOCKS) { 6149 dquot_alloc_block_nofail(ar->inode, 6150 EXT4_C2B(sbi, ar->len)); 6151 } else { 6152 while (ar->len && 6153 dquot_alloc_block(ar->inode, 6154 EXT4_C2B(sbi, ar->len))) { 6155 6156 ar->flags |= EXT4_MB_HINT_NOPREALLOC; 6157 ar->len--; 6158 } 6159 } 6160 inquota = ar->len; 6161 if (ar->len == 0) { 6162 *errp = -EDQUOT; 6163 goto out; 6164 } 6165 } 6166 6167 ac = kmem_cache_zalloc(ext4_ac_cachep, GFP_NOFS); 6168 if (!ac) { 6169 ar->len = 0; 6170 *errp = -ENOMEM; 6171 goto out; 6172 } 6173 6174 ext4_mb_initialize_context(ac, ar); 6175 6176 ac->ac_op = EXT4_MB_HISTORY_PREALLOC; 6177 seq = this_cpu_read(discard_pa_seq); 6178 if (!ext4_mb_use_preallocated(ac)) { 6179 ac->ac_op = EXT4_MB_HISTORY_ALLOC; 6180 ext4_mb_normalize_request(ac, ar); 6181 6182 *errp = ext4_mb_pa_alloc(ac); 6183 if (*errp) 6184 goto errout; 6185 repeat: 6186 /* allocate space in core */ 6187 *errp = ext4_mb_regular_allocator(ac); 6188 /* 6189 * pa allocated above is added to grp->bb_prealloc_list only 6190 * when we were able to allocate some block i.e. when 6191 * ac->ac_status == AC_STATUS_FOUND. 6192 * And error from above mean ac->ac_status != AC_STATUS_FOUND 6193 * So we have to free this pa here itself. 6194 */ 6195 if (*errp) { 6196 ext4_mb_pa_put_free(ac); 6197 ext4_discard_allocated_blocks(ac); 6198 goto errout; 6199 } 6200 if (ac->ac_status == AC_STATUS_FOUND && 6201 ac->ac_o_ex.fe_len >= ac->ac_f_ex.fe_len) 6202 ext4_mb_pa_put_free(ac); 6203 } 6204 if (likely(ac->ac_status == AC_STATUS_FOUND)) { 6205 *errp = ext4_mb_mark_diskspace_used(ac, handle, reserv_clstrs); 6206 if (*errp) { 6207 ext4_discard_allocated_blocks(ac); 6208 goto errout; 6209 } else { 6210 block = ext4_grp_offs_to_block(sb, &ac->ac_b_ex); 6211 ar->len = ac->ac_b_ex.fe_len; 6212 } 6213 } else { 6214 if (++retries < 3 && 6215 ext4_mb_discard_preallocations_should_retry(sb, ac, &seq)) 6216 goto repeat; 6217 /* 6218 * If block allocation fails then the pa allocated above 6219 * needs to be freed here itself. 6220 */ 6221 ext4_mb_pa_put_free(ac); 6222 *errp = -ENOSPC; 6223 } 6224 6225 if (*errp) { 6226 errout: 6227 ac->ac_b_ex.fe_len = 0; 6228 ar->len = 0; 6229 ext4_mb_show_ac(ac); 6230 } 6231 ext4_mb_release_context(ac); 6232 kmem_cache_free(ext4_ac_cachep, ac); 6233 out: 6234 if (inquota && ar->len < inquota) 6235 dquot_free_block(ar->inode, EXT4_C2B(sbi, inquota - ar->len)); 6236 if (!ar->len) { 6237 if ((ar->flags & EXT4_MB_DELALLOC_RESERVED) == 0) 6238 /* release all the reserved blocks if non delalloc */ 6239 percpu_counter_sub(&sbi->s_dirtyclusters_counter, 6240 reserv_clstrs); 6241 } 6242 6243 trace_ext4_allocate_blocks(ar, (unsigned long long)block); 6244 6245 return block; 6246 } 6247 6248 /* 6249 * We can merge two free data extents only if the physical blocks 6250 * are contiguous, AND the extents were freed by the same transaction, 6251 * AND the blocks are associated with the same group. 6252 */ 6253 static void ext4_try_merge_freed_extent(struct ext4_sb_info *sbi, 6254 struct ext4_free_data *entry, 6255 struct ext4_free_data *new_entry, 6256 struct rb_root *entry_rb_root) 6257 { 6258 if ((entry->efd_tid != new_entry->efd_tid) || 6259 (entry->efd_group != new_entry->efd_group)) 6260 return; 6261 if (entry->efd_start_cluster + entry->efd_count == 6262 new_entry->efd_start_cluster) { 6263 new_entry->efd_start_cluster = entry->efd_start_cluster; 6264 new_entry->efd_count += entry->efd_count; 6265 } else if (new_entry->efd_start_cluster + new_entry->efd_count == 6266 entry->efd_start_cluster) { 6267 new_entry->efd_count += entry->efd_count; 6268 } else 6269 return; 6270 spin_lock(&sbi->s_md_lock); 6271 list_del(&entry->efd_list); 6272 spin_unlock(&sbi->s_md_lock); 6273 rb_erase(&entry->efd_node, entry_rb_root); 6274 kmem_cache_free(ext4_free_data_cachep, entry); 6275 } 6276 6277 static noinline_for_stack void 6278 ext4_mb_free_metadata(handle_t *handle, struct ext4_buddy *e4b, 6279 struct ext4_free_data *new_entry) 6280 { 6281 ext4_group_t group = e4b->bd_group; 6282 ext4_grpblk_t cluster; 6283 ext4_grpblk_t clusters = new_entry->efd_count; 6284 struct ext4_free_data *entry; 6285 struct ext4_group_info *db = e4b->bd_info; 6286 struct super_block *sb = e4b->bd_sb; 6287 struct ext4_sb_info *sbi = EXT4_SB(sb); 6288 struct rb_node **n = &db->bb_free_root.rb_node, *node; 6289 struct rb_node *parent = NULL, *new_node; 6290 6291 BUG_ON(!ext4_handle_valid(handle)); 6292 BUG_ON(e4b->bd_bitmap_page == NULL); 6293 BUG_ON(e4b->bd_buddy_page == NULL); 6294 6295 new_node = &new_entry->efd_node; 6296 cluster = new_entry->efd_start_cluster; 6297 6298 if (!*n) { 6299 /* first free block exent. We need to 6300 protect buddy cache from being freed, 6301 * otherwise we'll refresh it from 6302 * on-disk bitmap and lose not-yet-available 6303 * blocks */ 6304 get_page(e4b->bd_buddy_page); 6305 get_page(e4b->bd_bitmap_page); 6306 } 6307 while (*n) { 6308 parent = *n; 6309 entry = rb_entry(parent, struct ext4_free_data, efd_node); 6310 if (cluster < entry->efd_start_cluster) 6311 n = &(*n)->rb_left; 6312 else if (cluster >= (entry->efd_start_cluster + entry->efd_count)) 6313 n = &(*n)->rb_right; 6314 else { 6315 ext4_grp_locked_error(sb, group, 0, 6316 ext4_group_first_block_no(sb, group) + 6317 EXT4_C2B(sbi, cluster), 6318 "Block already on to-be-freed list"); 6319 kmem_cache_free(ext4_free_data_cachep, new_entry); 6320 return; 6321 } 6322 } 6323 6324 rb_link_node(new_node, parent, n); 6325 rb_insert_color(new_node, &db->bb_free_root); 6326 6327 /* Now try to see the extent can be merged to left and right */ 6328 node = rb_prev(new_node); 6329 if (node) { 6330 entry = rb_entry(node, struct ext4_free_data, efd_node); 6331 ext4_try_merge_freed_extent(sbi, entry, new_entry, 6332 &(db->bb_free_root)); 6333 } 6334 6335 node = rb_next(new_node); 6336 if (node) { 6337 entry = rb_entry(node, struct ext4_free_data, efd_node); 6338 ext4_try_merge_freed_extent(sbi, entry, new_entry, 6339 &(db->bb_free_root)); 6340 } 6341 6342 spin_lock(&sbi->s_md_lock); 6343 list_add_tail(&new_entry->efd_list, &sbi->s_freed_data_list[new_entry->efd_tid & 1]); 6344 sbi->s_mb_free_pending += clusters; 6345 spin_unlock(&sbi->s_md_lock); 6346 } 6347 6348 static void ext4_free_blocks_simple(struct inode *inode, ext4_fsblk_t block, 6349 unsigned long count) 6350 { 6351 struct super_block *sb = inode->i_sb; 6352 ext4_group_t group; 6353 ext4_grpblk_t blkoff; 6354 6355 ext4_get_group_no_and_offset(sb, block, &group, &blkoff); 6356 ext4_mb_mark_context(NULL, sb, false, group, blkoff, count, 6357 EXT4_MB_BITMAP_MARKED_CHECK | 6358 EXT4_MB_SYNC_UPDATE, 6359 NULL); 6360 } 6361 6362 /** 6363 * ext4_mb_clear_bb() -- helper function for freeing blocks. 6364 * Used by ext4_free_blocks() 6365 * @handle: handle for this transaction 6366 * @inode: inode 6367 * @block: starting physical block to be freed 6368 * @count: number of blocks to be freed 6369 * @flags: flags used by ext4_free_blocks 6370 */ 6371 static void ext4_mb_clear_bb(handle_t *handle, struct inode *inode, 6372 ext4_fsblk_t block, unsigned long count, 6373 int flags) 6374 { 6375 struct super_block *sb = inode->i_sb; 6376 struct ext4_group_info *grp; 6377 unsigned int overflow; 6378 ext4_grpblk_t bit; 6379 ext4_group_t block_group; 6380 struct ext4_sb_info *sbi; 6381 struct ext4_buddy e4b; 6382 unsigned int count_clusters; 6383 int err = 0; 6384 int mark_flags = 0; 6385 ext4_grpblk_t changed; 6386 6387 sbi = EXT4_SB(sb); 6388 6389 if (!(flags & EXT4_FREE_BLOCKS_VALIDATED) && 6390 !ext4_inode_block_valid(inode, block, count)) { 6391 ext4_error(sb, "Freeing blocks in system zone - " 6392 "Block = %llu, count = %lu", block, count); 6393 /* err = 0. ext4_std_error should be a no op */ 6394 goto error_out; 6395 } 6396 flags |= EXT4_FREE_BLOCKS_VALIDATED; 6397 6398 do_more: 6399 overflow = 0; 6400 ext4_get_group_no_and_offset(sb, block, &block_group, &bit); 6401 6402 grp = ext4_get_group_info(sb, block_group); 6403 if (unlikely(!grp || EXT4_MB_GRP_BBITMAP_CORRUPT(grp))) 6404 return; 6405 6406 /* 6407 * Check to see if we are freeing blocks across a group 6408 * boundary. 6409 */ 6410 if (EXT4_C2B(sbi, bit) + count > EXT4_BLOCKS_PER_GROUP(sb)) { 6411 overflow = EXT4_C2B(sbi, bit) + count - 6412 EXT4_BLOCKS_PER_GROUP(sb); 6413 count -= overflow; 6414 /* The range changed so it's no longer validated */ 6415 flags &= ~EXT4_FREE_BLOCKS_VALIDATED; 6416 } 6417 count_clusters = EXT4_NUM_B2C(sbi, count); 6418 trace_ext4_mballoc_free(sb, inode, block_group, bit, count_clusters); 6419 6420 /* __GFP_NOFAIL: retry infinitely, ignore TIF_MEMDIE and memcg limit. */ 6421 err = ext4_mb_load_buddy_gfp(sb, block_group, &e4b, 6422 GFP_NOFS|__GFP_NOFAIL); 6423 if (err) 6424 goto error_out; 6425 6426 if (!(flags & EXT4_FREE_BLOCKS_VALIDATED) && 6427 !ext4_inode_block_valid(inode, block, count)) { 6428 ext4_error(sb, "Freeing blocks in system zone - " 6429 "Block = %llu, count = %lu", block, count); 6430 /* err = 0. ext4_std_error should be a no op */ 6431 goto error_clean; 6432 } 6433 6434 #ifdef AGGRESSIVE_CHECK 6435 mark_flags |= EXT4_MB_BITMAP_MARKED_CHECK; 6436 #endif 6437 err = ext4_mb_mark_context(handle, sb, false, block_group, bit, 6438 count_clusters, mark_flags, &changed); 6439 6440 6441 if (err && changed == 0) 6442 goto error_clean; 6443 6444 #ifdef AGGRESSIVE_CHECK 6445 BUG_ON(changed != count_clusters); 6446 #endif 6447 6448 /* 6449 * We need to make sure we don't reuse the freed block until after the 6450 * transaction is committed. We make an exception if the inode is to be 6451 * written in writeback mode since writeback mode has weak data 6452 * consistency guarantees. 6453 */ 6454 if (ext4_handle_valid(handle) && 6455 ((flags & EXT4_FREE_BLOCKS_METADATA) || 6456 !ext4_should_writeback_data(inode))) { 6457 struct ext4_free_data *new_entry; 6458 /* 6459 * We use __GFP_NOFAIL because ext4_free_blocks() is not allowed 6460 * to fail. 6461 */ 6462 new_entry = kmem_cache_alloc(ext4_free_data_cachep, 6463 GFP_NOFS|__GFP_NOFAIL); 6464 new_entry->efd_start_cluster = bit; 6465 new_entry->efd_group = block_group; 6466 new_entry->efd_count = count_clusters; 6467 new_entry->efd_tid = handle->h_transaction->t_tid; 6468 6469 ext4_lock_group(sb, block_group); 6470 ext4_mb_free_metadata(handle, &e4b, new_entry); 6471 } else { 6472 if (test_opt(sb, DISCARD)) { 6473 err = ext4_issue_discard(sb, block_group, bit, 6474 count_clusters, NULL); 6475 if (err && err != -EOPNOTSUPP) 6476 ext4_msg(sb, KERN_WARNING, "discard request in" 6477 " group:%u block:%d count:%lu failed" 6478 " with %d", block_group, bit, count, 6479 err); 6480 } else 6481 EXT4_MB_GRP_CLEAR_TRIMMED(e4b.bd_info); 6482 6483 ext4_lock_group(sb, block_group); 6484 mb_free_blocks(inode, &e4b, bit, count_clusters); 6485 } 6486 6487 ext4_unlock_group(sb, block_group); 6488 6489 /* 6490 * on a bigalloc file system, defer the s_freeclusters_counter 6491 * update to the caller (ext4_remove_space and friends) so they 6492 * can determine if a cluster freed here should be rereserved 6493 */ 6494 if (!(flags & EXT4_FREE_BLOCKS_RERESERVE_CLUSTER)) { 6495 if (!(flags & EXT4_FREE_BLOCKS_NO_QUOT_UPDATE)) 6496 dquot_free_block(inode, EXT4_C2B(sbi, count_clusters)); 6497 percpu_counter_add(&sbi->s_freeclusters_counter, 6498 count_clusters); 6499 } 6500 6501 if (overflow && !err) { 6502 block += count; 6503 count = overflow; 6504 ext4_mb_unload_buddy(&e4b); 6505 /* The range changed so it's no longer validated */ 6506 flags &= ~EXT4_FREE_BLOCKS_VALIDATED; 6507 goto do_more; 6508 } 6509 6510 error_clean: 6511 ext4_mb_unload_buddy(&e4b); 6512 error_out: 6513 ext4_std_error(sb, err); 6514 } 6515 6516 /** 6517 * ext4_free_blocks() -- Free given blocks and update quota 6518 * @handle: handle for this transaction 6519 * @inode: inode 6520 * @bh: optional buffer of the block to be freed 6521 * @block: starting physical block to be freed 6522 * @count: number of blocks to be freed 6523 * @flags: flags used by ext4_free_blocks 6524 */ 6525 void ext4_free_blocks(handle_t *handle, struct inode *inode, 6526 struct buffer_head *bh, ext4_fsblk_t block, 6527 unsigned long count, int flags) 6528 { 6529 struct super_block *sb = inode->i_sb; 6530 unsigned int overflow; 6531 struct ext4_sb_info *sbi; 6532 6533 sbi = EXT4_SB(sb); 6534 6535 if (bh) { 6536 if (block) 6537 BUG_ON(block != bh->b_blocknr); 6538 else 6539 block = bh->b_blocknr; 6540 } 6541 6542 if (sbi->s_mount_state & EXT4_FC_REPLAY) { 6543 ext4_free_blocks_simple(inode, block, EXT4_NUM_B2C(sbi, count)); 6544 return; 6545 } 6546 6547 might_sleep(); 6548 6549 if (!(flags & EXT4_FREE_BLOCKS_VALIDATED) && 6550 !ext4_inode_block_valid(inode, block, count)) { 6551 ext4_error(sb, "Freeing blocks not in datazone - " 6552 "block = %llu, count = %lu", block, count); 6553 return; 6554 } 6555 flags |= EXT4_FREE_BLOCKS_VALIDATED; 6556 6557 ext4_debug("freeing block %llu\n", block); 6558 trace_ext4_free_blocks(inode, block, count, flags); 6559 6560 if (bh && (flags & EXT4_FREE_BLOCKS_FORGET)) { 6561 BUG_ON(count > 1); 6562 6563 ext4_forget(handle, flags & EXT4_FREE_BLOCKS_METADATA, 6564 inode, bh, block); 6565 } 6566 6567 /* 6568 * If the extent to be freed does not begin on a cluster 6569 * boundary, we need to deal with partial clusters at the 6570 * beginning and end of the extent. Normally we will free 6571 * blocks at the beginning or the end unless we are explicitly 6572 * requested to avoid doing so. 6573 */ 6574 overflow = EXT4_PBLK_COFF(sbi, block); 6575 if (overflow) { 6576 if (flags & EXT4_FREE_BLOCKS_NOFREE_FIRST_CLUSTER) { 6577 overflow = sbi->s_cluster_ratio - overflow; 6578 block += overflow; 6579 if (count > overflow) 6580 count -= overflow; 6581 else 6582 return; 6583 } else { 6584 block -= overflow; 6585 count += overflow; 6586 } 6587 /* The range changed so it's no longer validated */ 6588 flags &= ~EXT4_FREE_BLOCKS_VALIDATED; 6589 } 6590 overflow = EXT4_LBLK_COFF(sbi, count); 6591 if (overflow) { 6592 if (flags & EXT4_FREE_BLOCKS_NOFREE_LAST_CLUSTER) { 6593 if (count > overflow) 6594 count -= overflow; 6595 else 6596 return; 6597 } else 6598 count += sbi->s_cluster_ratio - overflow; 6599 /* The range changed so it's no longer validated */ 6600 flags &= ~EXT4_FREE_BLOCKS_VALIDATED; 6601 } 6602 6603 if (!bh && (flags & EXT4_FREE_BLOCKS_FORGET)) { 6604 int i; 6605 int is_metadata = flags & EXT4_FREE_BLOCKS_METADATA; 6606 6607 for (i = 0; i < count; i++) { 6608 cond_resched(); 6609 if (is_metadata) 6610 bh = sb_find_get_block(inode->i_sb, block + i); 6611 ext4_forget(handle, is_metadata, inode, bh, block + i); 6612 } 6613 } 6614 6615 ext4_mb_clear_bb(handle, inode, block, count, flags); 6616 } 6617 6618 /** 6619 * ext4_group_add_blocks() -- Add given blocks to an existing group 6620 * @handle: handle to this transaction 6621 * @sb: super block 6622 * @block: start physical block to add to the block group 6623 * @count: number of blocks to free 6624 * 6625 * This marks the blocks as free in the bitmap and buddy. 6626 */ 6627 int ext4_group_add_blocks(handle_t *handle, struct super_block *sb, 6628 ext4_fsblk_t block, unsigned long count) 6629 { 6630 ext4_group_t block_group; 6631 ext4_grpblk_t bit; 6632 struct ext4_sb_info *sbi = EXT4_SB(sb); 6633 struct ext4_buddy e4b; 6634 int err = 0; 6635 ext4_fsblk_t first_cluster = EXT4_B2C(sbi, block); 6636 ext4_fsblk_t last_cluster = EXT4_B2C(sbi, block + count - 1); 6637 unsigned long cluster_count = last_cluster - first_cluster + 1; 6638 ext4_grpblk_t changed; 6639 6640 ext4_debug("Adding block(s) %llu-%llu\n", block, block + count - 1); 6641 6642 if (cluster_count == 0) 6643 return 0; 6644 6645 ext4_get_group_no_and_offset(sb, block, &block_group, &bit); 6646 /* 6647 * Check to see if we are freeing blocks across a group 6648 * boundary. 6649 */ 6650 if (bit + cluster_count > EXT4_CLUSTERS_PER_GROUP(sb)) { 6651 ext4_warning(sb, "too many blocks added to group %u", 6652 block_group); 6653 err = -EINVAL; 6654 goto error_out; 6655 } 6656 6657 err = ext4_mb_load_buddy(sb, block_group, &e4b); 6658 if (err) 6659 goto error_out; 6660 6661 if (!ext4_sb_block_valid(sb, NULL, block, count)) { 6662 ext4_error(sb, "Adding blocks in system zones - " 6663 "Block = %llu, count = %lu", 6664 block, count); 6665 err = -EINVAL; 6666 goto error_clean; 6667 } 6668 6669 err = ext4_mb_mark_context(handle, sb, false, block_group, bit, 6670 cluster_count, EXT4_MB_BITMAP_MARKED_CHECK, 6671 &changed); 6672 if (err && changed == 0) 6673 goto error_clean; 6674 6675 if (changed != cluster_count) 6676 ext4_error(sb, "bit already cleared in group %u", block_group); 6677 6678 ext4_lock_group(sb, block_group); 6679 mb_free_blocks(NULL, &e4b, bit, cluster_count); 6680 ext4_unlock_group(sb, block_group); 6681 percpu_counter_add(&sbi->s_freeclusters_counter, 6682 changed); 6683 6684 error_clean: 6685 ext4_mb_unload_buddy(&e4b); 6686 error_out: 6687 ext4_std_error(sb, err); 6688 return err; 6689 } 6690 6691 /** 6692 * ext4_trim_extent -- function to TRIM one single free extent in the group 6693 * @sb: super block for the file system 6694 * @start: starting block of the free extent in the alloc. group 6695 * @count: number of blocks to TRIM 6696 * @e4b: ext4 buddy for the group 6697 * 6698 * Trim "count" blocks starting at "start" in the "group". To assure that no 6699 * one will allocate those blocks, mark it as used in buddy bitmap. This must 6700 * be called with under the group lock. 6701 */ 6702 static int ext4_trim_extent(struct super_block *sb, 6703 int start, int count, struct ext4_buddy *e4b) 6704 __releases(bitlock) 6705 __acquires(bitlock) 6706 { 6707 struct ext4_free_extent ex; 6708 ext4_group_t group = e4b->bd_group; 6709 int ret = 0; 6710 6711 trace_ext4_trim_extent(sb, group, start, count); 6712 6713 assert_spin_locked(ext4_group_lock_ptr(sb, group)); 6714 6715 ex.fe_start = start; 6716 ex.fe_group = group; 6717 ex.fe_len = count; 6718 6719 /* 6720 * Mark blocks used, so no one can reuse them while 6721 * being trimmed. 6722 */ 6723 mb_mark_used(e4b, &ex); 6724 ext4_unlock_group(sb, group); 6725 ret = ext4_issue_discard(sb, group, start, count, NULL); 6726 ext4_lock_group(sb, group); 6727 mb_free_blocks(NULL, e4b, start, ex.fe_len); 6728 return ret; 6729 } 6730 6731 static ext4_grpblk_t ext4_last_grp_cluster(struct super_block *sb, 6732 ext4_group_t grp) 6733 { 6734 if (grp < ext4_get_groups_count(sb)) 6735 return EXT4_CLUSTERS_PER_GROUP(sb) - 1; 6736 return (ext4_blocks_count(EXT4_SB(sb)->s_es) - 6737 ext4_group_first_block_no(sb, grp) - 1) >> 6738 EXT4_CLUSTER_BITS(sb); 6739 } 6740 6741 static bool ext4_trim_interrupted(void) 6742 { 6743 return fatal_signal_pending(current) || freezing(current); 6744 } 6745 6746 static int ext4_try_to_trim_range(struct super_block *sb, 6747 struct ext4_buddy *e4b, ext4_grpblk_t start, 6748 ext4_grpblk_t max, ext4_grpblk_t minblocks) 6749 __acquires(ext4_group_lock_ptr(sb, e4b->bd_group)) 6750 __releases(ext4_group_lock_ptr(sb, e4b->bd_group)) 6751 { 6752 ext4_grpblk_t next, count, free_count; 6753 bool set_trimmed = false; 6754 void *bitmap; 6755 6756 bitmap = e4b->bd_bitmap; 6757 if (start == 0 && max >= ext4_last_grp_cluster(sb, e4b->bd_group)) 6758 set_trimmed = true; 6759 start = max(e4b->bd_info->bb_first_free, start); 6760 count = 0; 6761 free_count = 0; 6762 6763 while (start <= max) { 6764 start = mb_find_next_zero_bit(bitmap, max + 1, start); 6765 if (start > max) 6766 break; 6767 next = mb_find_next_bit(bitmap, max + 1, start); 6768 6769 if ((next - start) >= minblocks) { 6770 int ret = ext4_trim_extent(sb, start, next - start, e4b); 6771 6772 if (ret && ret != -EOPNOTSUPP) 6773 return count; 6774 count += next - start; 6775 } 6776 free_count += next - start; 6777 start = next + 1; 6778 6779 if (ext4_trim_interrupted()) 6780 return count; 6781 6782 if (need_resched()) { 6783 ext4_unlock_group(sb, e4b->bd_group); 6784 cond_resched(); 6785 ext4_lock_group(sb, e4b->bd_group); 6786 } 6787 6788 if ((e4b->bd_info->bb_free - free_count) < minblocks) 6789 break; 6790 } 6791 6792 if (set_trimmed) 6793 EXT4_MB_GRP_SET_TRIMMED(e4b->bd_info); 6794 6795 return count; 6796 } 6797 6798 /** 6799 * ext4_trim_all_free -- function to trim all free space in alloc. group 6800 * @sb: super block for file system 6801 * @group: group to be trimmed 6802 * @start: first group block to examine 6803 * @max: last group block to examine 6804 * @minblocks: minimum extent block count 6805 * 6806 * ext4_trim_all_free walks through group's block bitmap searching for free 6807 * extents. When the free extent is found, mark it as used in group buddy 6808 * bitmap. Then issue a TRIM command on this extent and free the extent in 6809 * the group buddy bitmap. 6810 */ 6811 static ext4_grpblk_t 6812 ext4_trim_all_free(struct super_block *sb, ext4_group_t group, 6813 ext4_grpblk_t start, ext4_grpblk_t max, 6814 ext4_grpblk_t minblocks) 6815 { 6816 struct ext4_buddy e4b; 6817 int ret; 6818 6819 trace_ext4_trim_all_free(sb, group, start, max); 6820 6821 ret = ext4_mb_load_buddy(sb, group, &e4b); 6822 if (ret) { 6823 ext4_warning(sb, "Error %d loading buddy information for %u", 6824 ret, group); 6825 return ret; 6826 } 6827 6828 ext4_lock_group(sb, group); 6829 6830 if (!EXT4_MB_GRP_WAS_TRIMMED(e4b.bd_info) || 6831 minblocks < EXT4_SB(sb)->s_last_trim_minblks) 6832 ret = ext4_try_to_trim_range(sb, &e4b, start, max, minblocks); 6833 else 6834 ret = 0; 6835 6836 ext4_unlock_group(sb, group); 6837 ext4_mb_unload_buddy(&e4b); 6838 6839 ext4_debug("trimmed %d blocks in the group %d\n", 6840 ret, group); 6841 6842 return ret; 6843 } 6844 6845 /** 6846 * ext4_trim_fs() -- trim ioctl handle function 6847 * @sb: superblock for filesystem 6848 * @range: fstrim_range structure 6849 * 6850 * start: First Byte to trim 6851 * len: number of Bytes to trim from start 6852 * minlen: minimum extent length in Bytes 6853 * ext4_trim_fs goes through all allocation groups containing Bytes from 6854 * start to start+len. For each such a group ext4_trim_all_free function 6855 * is invoked to trim all free space. 6856 */ 6857 int ext4_trim_fs(struct super_block *sb, struct fstrim_range *range) 6858 { 6859 unsigned int discard_granularity = bdev_discard_granularity(sb->s_bdev); 6860 struct ext4_group_info *grp; 6861 ext4_group_t group, first_group, last_group; 6862 ext4_grpblk_t cnt = 0, first_cluster, last_cluster; 6863 uint64_t start, end, minlen, trimmed = 0; 6864 ext4_fsblk_t first_data_blk = 6865 le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block); 6866 ext4_fsblk_t max_blks = ext4_blocks_count(EXT4_SB(sb)->s_es); 6867 int ret = 0; 6868 6869 start = range->start >> sb->s_blocksize_bits; 6870 end = start + (range->len >> sb->s_blocksize_bits) - 1; 6871 minlen = EXT4_NUM_B2C(EXT4_SB(sb), 6872 range->minlen >> sb->s_blocksize_bits); 6873 6874 if (minlen > EXT4_CLUSTERS_PER_GROUP(sb) || 6875 start >= max_blks || 6876 range->len < sb->s_blocksize) 6877 return -EINVAL; 6878 /* No point to try to trim less than discard granularity */ 6879 if (range->minlen < discard_granularity) { 6880 minlen = EXT4_NUM_B2C(EXT4_SB(sb), 6881 discard_granularity >> sb->s_blocksize_bits); 6882 if (minlen > EXT4_CLUSTERS_PER_GROUP(sb)) 6883 goto out; 6884 } 6885 if (end >= max_blks - 1) 6886 end = max_blks - 1; 6887 if (end <= first_data_blk) 6888 goto out; 6889 if (start < first_data_blk) 6890 start = first_data_blk; 6891 6892 /* Determine first and last group to examine based on start and end */ 6893 ext4_get_group_no_and_offset(sb, (ext4_fsblk_t) start, 6894 &first_group, &first_cluster); 6895 ext4_get_group_no_and_offset(sb, (ext4_fsblk_t) end, 6896 &last_group, &last_cluster); 6897 6898 /* end now represents the last cluster to discard in this group */ 6899 end = EXT4_CLUSTERS_PER_GROUP(sb) - 1; 6900 6901 for (group = first_group; group <= last_group; group++) { 6902 if (ext4_trim_interrupted()) 6903 break; 6904 grp = ext4_get_group_info(sb, group); 6905 if (!grp) 6906 continue; 6907 /* We only do this if the grp has never been initialized */ 6908 if (unlikely(EXT4_MB_GRP_NEED_INIT(grp))) { 6909 ret = ext4_mb_init_group(sb, group, GFP_NOFS); 6910 if (ret) 6911 break; 6912 } 6913 6914 /* 6915 * For all the groups except the last one, last cluster will 6916 * always be EXT4_CLUSTERS_PER_GROUP(sb)-1, so we only need to 6917 * change it for the last group, note that last_cluster is 6918 * already computed earlier by ext4_get_group_no_and_offset() 6919 */ 6920 if (group == last_group) 6921 end = last_cluster; 6922 if (grp->bb_free >= minlen) { 6923 cnt = ext4_trim_all_free(sb, group, first_cluster, 6924 end, minlen); 6925 if (cnt < 0) { 6926 ret = cnt; 6927 break; 6928 } 6929 trimmed += cnt; 6930 } 6931 6932 /* 6933 * For every group except the first one, we are sure 6934 * that the first cluster to discard will be cluster #0. 6935 */ 6936 first_cluster = 0; 6937 } 6938 6939 if (!ret) 6940 EXT4_SB(sb)->s_last_trim_minblks = minlen; 6941 6942 out: 6943 range->len = EXT4_C2B(EXT4_SB(sb), trimmed) << sb->s_blocksize_bits; 6944 return ret; 6945 } 6946 6947 /* Iterate all the free extents in the group. */ 6948 int 6949 ext4_mballoc_query_range( 6950 struct super_block *sb, 6951 ext4_group_t group, 6952 ext4_grpblk_t start, 6953 ext4_grpblk_t end, 6954 ext4_mballoc_query_range_fn formatter, 6955 void *priv) 6956 { 6957 void *bitmap; 6958 ext4_grpblk_t next; 6959 struct ext4_buddy e4b; 6960 int error; 6961 6962 error = ext4_mb_load_buddy(sb, group, &e4b); 6963 if (error) 6964 return error; 6965 bitmap = e4b.bd_bitmap; 6966 6967 ext4_lock_group(sb, group); 6968 6969 start = max(e4b.bd_info->bb_first_free, start); 6970 if (end >= EXT4_CLUSTERS_PER_GROUP(sb)) 6971 end = EXT4_CLUSTERS_PER_GROUP(sb) - 1; 6972 6973 while (start <= end) { 6974 start = mb_find_next_zero_bit(bitmap, end + 1, start); 6975 if (start > end) 6976 break; 6977 next = mb_find_next_bit(bitmap, end + 1, start); 6978 6979 ext4_unlock_group(sb, group); 6980 error = formatter(sb, group, start, next - start, priv); 6981 if (error) 6982 goto out_unload; 6983 ext4_lock_group(sb, group); 6984 6985 start = next + 1; 6986 } 6987 6988 ext4_unlock_group(sb, group); 6989 out_unload: 6990 ext4_mb_unload_buddy(&e4b); 6991 6992 return error; 6993 } 6994 6995 #ifdef CONFIG_EXT4_KUNIT_TESTS 6996 #include "mballoc-test.c" 6997 #endif 6998