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1// SPDX-License-Identifier: GPL-2.02 3#include "misc.h"4#include "ctree.h"5#include "block-rsv.h"6#include "space-info.h"7#include "transaction.h"8#include "block-group.h"9#include "fs.h"10#include "accessors.h"11 12/*13 * HOW DO BLOCK RESERVES WORK14 *15 * Think of block_rsv's as buckets for logically grouped metadata16 * reservations. Each block_rsv has a ->size and a ->reserved. ->size is17 * how large we want our block rsv to be, ->reserved is how much space is18 * currently reserved for this block reserve.19 *20 * ->failfast exists for the truncate case, and is described below.21 *22 * NORMAL OPERATION23 *24 * -> Reserve25 * Entrance: btrfs_block_rsv_add, btrfs_block_rsv_refill26 *27 * We call into btrfs_reserve_metadata_bytes() with our bytes, which is28 * accounted for in space_info->bytes_may_use, and then add the bytes to29 * ->reserved, and ->size in the case of btrfs_block_rsv_add.30 *31 * ->size is an over-estimation of how much we may use for a particular32 * operation.33 *34 * -> Use35 * Entrance: btrfs_use_block_rsv36 *37 * When we do a btrfs_alloc_tree_block() we call into btrfs_use_block_rsv()38 * to determine the appropriate block_rsv to use, and then verify that39 * ->reserved has enough space for our tree block allocation. Once40 * successful we subtract fs_info->nodesize from ->reserved.41 *42 * -> Finish43 * Entrance: btrfs_block_rsv_release44 *45 * We are finished with our operation, subtract our individual reservation46 * from ->size, and then subtract ->size from ->reserved and free up the47 * excess if there is any.48 *49 * There is some logic here to refill the delayed refs rsv or the global rsv50 * as needed, otherwise the excess is subtracted from51 * space_info->bytes_may_use.52 *53 * TYPES OF BLOCK RESERVES54 *55 * BLOCK_RSV_TRANS, BLOCK_RSV_DELOPS, BLOCK_RSV_CHUNK56 * These behave normally, as described above, just within the confines of the57 * lifetime of their particular operation (transaction for the whole trans58 * handle lifetime, for example).59 *60 * BLOCK_RSV_GLOBAL61 * It is impossible to properly account for all the space that may be required62 * to make our extent tree updates. This block reserve acts as an overflow63 * buffer in case our delayed refs reserve does not reserve enough space to64 * update the extent tree.65 *66 * We can steal from this in some cases as well, notably on evict() or67 * truncate() in order to help users recover from ENOSPC conditions.68 *69 * BLOCK_RSV_DELALLOC70 * The individual item sizes are determined by the per-inode size71 * calculations, which are described with the delalloc code. This is pretty72 * straightforward, it's just the calculation of ->size encodes a lot of73 * different items, and thus it gets used when updating inodes, inserting file74 * extents, and inserting checksums.75 *76 * BLOCK_RSV_DELREFS77 * We keep a running tally of how many delayed refs we have on the system.78 * We assume each one of these delayed refs are going to use a full79 * reservation. We use the transaction items and pre-reserve space for every80 * operation, and use this reservation to refill any gap between ->size and81 * ->reserved that may exist.82 *83 * From there it's straightforward, removing a delayed ref means we remove its84 * count from ->size and free up reservations as necessary. Since this is85 * the most dynamic block reserve in the system, we will try to refill this86 * block reserve first with any excess returned by any other block reserve.87 *88 * BLOCK_RSV_EMPTY89 * This is the fallback block reserve to make us try to reserve space if we90 * don't have a specific bucket for this allocation. It is mostly used for91 * updating the device tree and such, since that is a separate pool we're92 * content to just reserve space from the space_info on demand.93 *94 * BLOCK_RSV_TEMP95 * This is used by things like truncate and iput. We will temporarily96 * allocate a block reserve, set it to some size, and then truncate bytes97 * until we have no space left. With ->failfast set we'll simply return98 * ENOSPC from btrfs_use_block_rsv() to signal that we need to unwind and try99 * to make a new reservation. This is because these operations are100 * unbounded, so we want to do as much work as we can, and then back off and101 * re-reserve.102 */103 104static u64 block_rsv_release_bytes(struct btrfs_fs_info *fs_info,105 struct btrfs_block_rsv *block_rsv,106 struct btrfs_block_rsv *dest, u64 num_bytes,107 u64 *qgroup_to_release_ret)108{109 struct btrfs_space_info *space_info = block_rsv->space_info;110 u64 qgroup_to_release = 0;111 u64 ret;112 113 spin_lock(&block_rsv->lock);114 if (num_bytes == (u64)-1) {115 num_bytes = block_rsv->size;116 qgroup_to_release = block_rsv->qgroup_rsv_size;117 }118 block_rsv->size -= num_bytes;119 if (block_rsv->reserved >= block_rsv->size) {120 num_bytes = block_rsv->reserved - block_rsv->size;121 block_rsv->reserved = block_rsv->size;122 block_rsv->full = true;123 } else {124 num_bytes = 0;125 }126 if (qgroup_to_release_ret &&127 block_rsv->qgroup_rsv_reserved >= block_rsv->qgroup_rsv_size) {128 qgroup_to_release = block_rsv->qgroup_rsv_reserved -129 block_rsv->qgroup_rsv_size;130 block_rsv->qgroup_rsv_reserved = block_rsv->qgroup_rsv_size;131 } else {132 qgroup_to_release = 0;133 }134 spin_unlock(&block_rsv->lock);135 136 ret = num_bytes;137 if (num_bytes > 0) {138 if (dest) {139 spin_lock(&dest->lock);140 if (!dest->full) {141 u64 bytes_to_add;142 143 bytes_to_add = dest->size - dest->reserved;144 bytes_to_add = min(num_bytes, bytes_to_add);145 dest->reserved += bytes_to_add;146 if (dest->reserved >= dest->size)147 dest->full = true;148 num_bytes -= bytes_to_add;149 }150 spin_unlock(&dest->lock);151 }152 if (num_bytes)153 btrfs_space_info_free_bytes_may_use(fs_info,154 space_info,155 num_bytes);156 }157 if (qgroup_to_release_ret)158 *qgroup_to_release_ret = qgroup_to_release;159 return ret;160}161 162int btrfs_block_rsv_migrate(struct btrfs_block_rsv *src,163 struct btrfs_block_rsv *dst, u64 num_bytes,164 bool update_size)165{166 int ret;167 168 ret = btrfs_block_rsv_use_bytes(src, num_bytes);169 if (ret)170 return ret;171 172 btrfs_block_rsv_add_bytes(dst, num_bytes, update_size);173 return 0;174}175 176void btrfs_init_block_rsv(struct btrfs_block_rsv *rsv, enum btrfs_rsv_type type)177{178 memset(rsv, 0, sizeof(*rsv));179 spin_lock_init(&rsv->lock);180 rsv->type = type;181}182 183void btrfs_init_metadata_block_rsv(struct btrfs_fs_info *fs_info,184 struct btrfs_block_rsv *rsv,185 enum btrfs_rsv_type type)186{187 btrfs_init_block_rsv(rsv, type);188 rsv->space_info = btrfs_find_space_info(fs_info,189 BTRFS_BLOCK_GROUP_METADATA);190}191 192struct btrfs_block_rsv *btrfs_alloc_block_rsv(struct btrfs_fs_info *fs_info,193 enum btrfs_rsv_type type)194{195 struct btrfs_block_rsv *block_rsv;196 197 block_rsv = kmalloc(sizeof(*block_rsv), GFP_NOFS);198 if (!block_rsv)199 return NULL;200 201 btrfs_init_metadata_block_rsv(fs_info, block_rsv, type);202 return block_rsv;203}204 205void btrfs_free_block_rsv(struct btrfs_fs_info *fs_info,206 struct btrfs_block_rsv *rsv)207{208 if (!rsv)209 return;210 btrfs_block_rsv_release(fs_info, rsv, (u64)-1, NULL);211 kfree(rsv);212}213 214int btrfs_block_rsv_add(struct btrfs_fs_info *fs_info,215 struct btrfs_block_rsv *block_rsv, u64 num_bytes,216 enum btrfs_reserve_flush_enum flush)217{218 int ret;219 220 if (num_bytes == 0)221 return 0;222 223 ret = btrfs_reserve_metadata_bytes(fs_info, block_rsv->space_info,224 num_bytes, flush);225 if (!ret)226 btrfs_block_rsv_add_bytes(block_rsv, num_bytes, true);227 228 return ret;229}230 231int btrfs_block_rsv_check(struct btrfs_block_rsv *block_rsv, int min_percent)232{233 u64 num_bytes = 0;234 int ret = -ENOSPC;235 236 spin_lock(&block_rsv->lock);237 num_bytes = mult_perc(block_rsv->size, min_percent);238 if (block_rsv->reserved >= num_bytes)239 ret = 0;240 spin_unlock(&block_rsv->lock);241 242 return ret;243}244 245int btrfs_block_rsv_refill(struct btrfs_fs_info *fs_info,246 struct btrfs_block_rsv *block_rsv, u64 num_bytes,247 enum btrfs_reserve_flush_enum flush)248{249 int ret = -ENOSPC;250 251 if (!block_rsv)252 return 0;253 254 spin_lock(&block_rsv->lock);255 if (block_rsv->reserved >= num_bytes)256 ret = 0;257 else258 num_bytes -= block_rsv->reserved;259 spin_unlock(&block_rsv->lock);260 261 if (!ret)262 return 0;263 264 ret = btrfs_reserve_metadata_bytes(fs_info, block_rsv->space_info,265 num_bytes, flush);266 if (!ret) {267 btrfs_block_rsv_add_bytes(block_rsv, num_bytes, false);268 return 0;269 }270 271 return ret;272}273 274u64 btrfs_block_rsv_release(struct btrfs_fs_info *fs_info,275 struct btrfs_block_rsv *block_rsv, u64 num_bytes,276 u64 *qgroup_to_release)277{278 struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;279 struct btrfs_block_rsv *delayed_rsv = &fs_info->delayed_refs_rsv;280 struct btrfs_block_rsv *target = NULL;281 282 /*283 * If we are a delayed block reserve then push to the global rsv,284 * otherwise dump into the global delayed reserve if it is not full.285 */286 if (block_rsv->type == BTRFS_BLOCK_RSV_DELOPS)287 target = global_rsv;288 else if (block_rsv != global_rsv && !btrfs_block_rsv_full(delayed_rsv))289 target = delayed_rsv;290 291 if (target && block_rsv->space_info != target->space_info)292 target = NULL;293 294 return block_rsv_release_bytes(fs_info, block_rsv, target, num_bytes,295 qgroup_to_release);296}297 298int btrfs_block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv, u64 num_bytes)299{300 int ret = -ENOSPC;301 302 spin_lock(&block_rsv->lock);303 if (block_rsv->reserved >= num_bytes) {304 block_rsv->reserved -= num_bytes;305 if (block_rsv->reserved < block_rsv->size)306 block_rsv->full = false;307 ret = 0;308 }309 spin_unlock(&block_rsv->lock);310 return ret;311}312 313void btrfs_block_rsv_add_bytes(struct btrfs_block_rsv *block_rsv,314 u64 num_bytes, bool update_size)315{316 spin_lock(&block_rsv->lock);317 block_rsv->reserved += num_bytes;318 if (update_size)319 block_rsv->size += num_bytes;320 else if (block_rsv->reserved >= block_rsv->size)321 block_rsv->full = true;322 spin_unlock(&block_rsv->lock);323}324 325void btrfs_update_global_block_rsv(struct btrfs_fs_info *fs_info)326{327 struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;328 struct btrfs_space_info *sinfo = block_rsv->space_info;329 struct btrfs_root *root, *tmp;330 u64 num_bytes = btrfs_root_used(&fs_info->tree_root->root_item);331 unsigned int min_items = 1;332 333 /*334 * The global block rsv is based on the size of the extent tree, the335 * checksum tree and the root tree. If the fs is empty we want to set336 * it to a minimal amount for safety.337 *338 * We also are going to need to modify the minimum of the tree root and339 * any global roots we could touch.340 */341 read_lock(&fs_info->global_root_lock);342 rbtree_postorder_for_each_entry_safe(root, tmp, &fs_info->global_root_tree,343 rb_node) {344 if (btrfs_root_id(root) == BTRFS_EXTENT_TREE_OBJECTID ||345 btrfs_root_id(root) == BTRFS_CSUM_TREE_OBJECTID ||346 btrfs_root_id(root) == BTRFS_FREE_SPACE_TREE_OBJECTID) {347 num_bytes += btrfs_root_used(&root->root_item);348 min_items++;349 }350 }351 read_unlock(&fs_info->global_root_lock);352 353 if (btrfs_fs_compat_ro(fs_info, BLOCK_GROUP_TREE)) {354 num_bytes += btrfs_root_used(&fs_info->block_group_root->root_item);355 min_items++;356 }357 358 if (btrfs_fs_incompat(fs_info, RAID_STRIPE_TREE)) {359 num_bytes += btrfs_root_used(&fs_info->stripe_root->root_item);360 min_items++;361 }362 363 /*364 * But we also want to reserve enough space so we can do the fallback365 * global reserve for an unlink, which is an additional366 * BTRFS_UNLINK_METADATA_UNITS items.367 *368 * But we also need space for the delayed ref updates from the unlink,369 * so add BTRFS_UNLINK_METADATA_UNITS units for delayed refs, one for370 * each unlink metadata item.371 */372 min_items += BTRFS_UNLINK_METADATA_UNITS;373 374 num_bytes = max_t(u64, num_bytes,375 btrfs_calc_insert_metadata_size(fs_info, min_items) +376 btrfs_calc_delayed_ref_bytes(fs_info,377 BTRFS_UNLINK_METADATA_UNITS));378 379 spin_lock(&sinfo->lock);380 spin_lock(&block_rsv->lock);381 382 block_rsv->size = min_t(u64, num_bytes, SZ_512M);383 384 if (block_rsv->reserved < block_rsv->size) {385 num_bytes = block_rsv->size - block_rsv->reserved;386 btrfs_space_info_update_bytes_may_use(fs_info, sinfo,387 num_bytes);388 block_rsv->reserved = block_rsv->size;389 } else if (block_rsv->reserved > block_rsv->size) {390 num_bytes = block_rsv->reserved - block_rsv->size;391 btrfs_space_info_update_bytes_may_use(fs_info, sinfo,392 -num_bytes);393 block_rsv->reserved = block_rsv->size;394 btrfs_try_granting_tickets(fs_info, sinfo);395 }396 397 block_rsv->full = (block_rsv->reserved == block_rsv->size);398 399 if (block_rsv->size >= sinfo->total_bytes)400 sinfo->force_alloc = CHUNK_ALLOC_FORCE;401 spin_unlock(&block_rsv->lock);402 spin_unlock(&sinfo->lock);403}404 405void btrfs_init_root_block_rsv(struct btrfs_root *root)406{407 struct btrfs_fs_info *fs_info = root->fs_info;408 409 switch (btrfs_root_id(root)) {410 case BTRFS_CSUM_TREE_OBJECTID:411 case BTRFS_EXTENT_TREE_OBJECTID:412 case BTRFS_FREE_SPACE_TREE_OBJECTID:413 case BTRFS_BLOCK_GROUP_TREE_OBJECTID:414 case BTRFS_RAID_STRIPE_TREE_OBJECTID:415 root->block_rsv = &fs_info->delayed_refs_rsv;416 break;417 case BTRFS_ROOT_TREE_OBJECTID:418 case BTRFS_DEV_TREE_OBJECTID:419 case BTRFS_QUOTA_TREE_OBJECTID:420 root->block_rsv = &fs_info->global_block_rsv;421 break;422 case BTRFS_CHUNK_TREE_OBJECTID:423 root->block_rsv = &fs_info->chunk_block_rsv;424 break;425 default:426 root->block_rsv = NULL;427 break;428 }429}430 431void btrfs_init_global_block_rsv(struct btrfs_fs_info *fs_info)432{433 struct btrfs_space_info *space_info;434 435 space_info = btrfs_find_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);436 fs_info->chunk_block_rsv.space_info = space_info;437 438 space_info = btrfs_find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);439 fs_info->global_block_rsv.space_info = space_info;440 fs_info->trans_block_rsv.space_info = space_info;441 fs_info->empty_block_rsv.space_info = space_info;442 fs_info->delayed_block_rsv.space_info = space_info;443 fs_info->delayed_refs_rsv.space_info = space_info;444 445 btrfs_update_global_block_rsv(fs_info);446}447 448void btrfs_release_global_block_rsv(struct btrfs_fs_info *fs_info)449{450 btrfs_block_rsv_release(fs_info, &fs_info->global_block_rsv, (u64)-1,451 NULL);452 WARN_ON(fs_info->trans_block_rsv.size > 0);453 WARN_ON(fs_info->trans_block_rsv.reserved > 0);454 WARN_ON(fs_info->chunk_block_rsv.size > 0);455 WARN_ON(fs_info->chunk_block_rsv.reserved > 0);456 WARN_ON(fs_info->delayed_block_rsv.size > 0);457 WARN_ON(fs_info->delayed_block_rsv.reserved > 0);458 WARN_ON(fs_info->delayed_refs_rsv.reserved > 0);459 WARN_ON(fs_info->delayed_refs_rsv.size > 0);460}461 462static struct btrfs_block_rsv *get_block_rsv(463 const struct btrfs_trans_handle *trans,464 const struct btrfs_root *root)465{466 struct btrfs_fs_info *fs_info = root->fs_info;467 struct btrfs_block_rsv *block_rsv = NULL;468 469 if (test_bit(BTRFS_ROOT_SHAREABLE, &root->state) ||470 (root == fs_info->uuid_root) ||471 (trans->adding_csums && btrfs_root_id(root) == BTRFS_CSUM_TREE_OBJECTID))472 block_rsv = trans->block_rsv;473 474 if (!block_rsv)475 block_rsv = root->block_rsv;476 477 if (!block_rsv)478 block_rsv = &fs_info->empty_block_rsv;479 480 return block_rsv;481}482 483struct btrfs_block_rsv *btrfs_use_block_rsv(struct btrfs_trans_handle *trans,484 struct btrfs_root *root,485 u32 blocksize)486{487 struct btrfs_fs_info *fs_info = root->fs_info;488 struct btrfs_block_rsv *block_rsv;489 struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;490 int ret;491 bool global_updated = false;492 493 block_rsv = get_block_rsv(trans, root);494 495 if (unlikely(btrfs_block_rsv_size(block_rsv) == 0))496 goto try_reserve;497again:498 ret = btrfs_block_rsv_use_bytes(block_rsv, blocksize);499 if (!ret)500 return block_rsv;501 502 if (block_rsv->failfast)503 return ERR_PTR(ret);504 505 if (block_rsv->type == BTRFS_BLOCK_RSV_GLOBAL && !global_updated) {506 global_updated = true;507 btrfs_update_global_block_rsv(fs_info);508 goto again;509 }510 511 /*512 * The global reserve still exists to save us from ourselves, so don't513 * warn_on if we are short on our delayed refs reserve.514 */515 if (block_rsv->type != BTRFS_BLOCK_RSV_DELREFS &&516 btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {517 static DEFINE_RATELIMIT_STATE(_rs,518 DEFAULT_RATELIMIT_INTERVAL * 10,519 /*DEFAULT_RATELIMIT_BURST*/ 1);520 if (__ratelimit(&_rs))521 WARN(1, KERN_DEBUG522 "BTRFS: block rsv %d returned %d\n",523 block_rsv->type, ret);524 }525try_reserve:526 ret = btrfs_reserve_metadata_bytes(fs_info, block_rsv->space_info,527 blocksize, BTRFS_RESERVE_NO_FLUSH);528 if (!ret)529 return block_rsv;530 /*531 * If we couldn't reserve metadata bytes try and use some from532 * the global reserve if its space type is the same as the global533 * reservation.534 */535 if (block_rsv->type != BTRFS_BLOCK_RSV_GLOBAL &&536 block_rsv->space_info == global_rsv->space_info) {537 ret = btrfs_block_rsv_use_bytes(global_rsv, blocksize);538 if (!ret)539 return global_rsv;540 }541 542 /*543 * All hope is lost, but of course our reservations are overly544 * pessimistic, so instead of possibly having an ENOSPC abort here, try545 * one last time to force a reservation if there's enough actual space546 * on disk to make the reservation.547 */548 ret = btrfs_reserve_metadata_bytes(fs_info, block_rsv->space_info, blocksize,549 BTRFS_RESERVE_FLUSH_EMERGENCY);550 if (!ret)551 return block_rsv;552 553 return ERR_PTR(ret);554}555 556int btrfs_check_trunc_cache_free_space(const struct btrfs_fs_info *fs_info,557 struct btrfs_block_rsv *rsv)558{559 u64 needed_bytes;560 int ret;561 562 /* 1 for slack space, 1 for updating the inode */563 needed_bytes = btrfs_calc_insert_metadata_size(fs_info, 1) +564 btrfs_calc_metadata_size(fs_info, 1);565 566 spin_lock(&rsv->lock);567 if (rsv->reserved < needed_bytes)568 ret = -ENOSPC;569 else570 ret = 0;571 spin_unlock(&rsv->lock);572 return ret;573}574