1// SPDX-License-Identifier: GPL-2.0
   2
 
 
   3#include "misc.h"
   4#include "ctree.h"
   5#include "space-info.h"
   6#include "sysfs.h"
   7#include "volumes.h"
   8#include "free-space-cache.h"
   9#include "ordered-data.h"
  10#include "transaction.h"
  11#include "block-group.h"
  12#include "zoned.h"
  13#include "fs.h"
  14#include "accessors.h"
  15#include "extent-tree.h"
  16
  17/*
  18 * HOW DOES SPACE RESERVATION WORK
  19 *
  20 * If you want to know about delalloc specifically, there is a separate comment
  21 * for that with the delalloc code.  This comment is about how the whole system
  22 * works generally.
  23 *
  24 * BASIC CONCEPTS
  25 *
  26 *   1) space_info.  This is the ultimate arbiter of how much space we can use.
  27 *   There's a description of the bytes_ fields with the struct declaration,
  28 *   refer to that for specifics on each field.  Suffice it to say that for
  29 *   reservations we care about total_bytes - SUM(space_info->bytes_) when
  30 *   determining if there is space to make an allocation.  There is a space_info
  31 *   for METADATA, SYSTEM, and DATA areas.
  32 *
  33 *   2) block_rsv's.  These are basically buckets for every different type of
  34 *   metadata reservation we have.  You can see the comment in the block_rsv
  35 *   code on the rules for each type, but generally block_rsv->reserved is how
  36 *   much space is accounted for in space_info->bytes_may_use.
  37 *
  38 *   3) btrfs_calc*_size.  These are the worst case calculations we used based
  39 *   on the number of items we will want to modify.  We have one for changing
  40 *   items, and one for inserting new items.  Generally we use these helpers to
  41 *   determine the size of the block reserves, and then use the actual bytes
  42 *   values to adjust the space_info counters.
  43 *
  44 * MAKING RESERVATIONS, THE NORMAL CASE
  45 *
  46 *   We call into either btrfs_reserve_data_bytes() or
  47 *   btrfs_reserve_metadata_bytes(), depending on which we're looking for, with
  48 *   num_bytes we want to reserve.
  49 *
  50 *   ->reserve
  51 *     space_info->bytes_may_reserve += num_bytes
  52 *
  53 *   ->extent allocation
  54 *     Call btrfs_add_reserved_bytes() which does
  55 *     space_info->bytes_may_reserve -= num_bytes
  56 *     space_info->bytes_reserved += extent_bytes
  57 *
  58 *   ->insert reference
  59 *     Call btrfs_update_block_group() which does
  60 *     space_info->bytes_reserved -= extent_bytes
  61 *     space_info->bytes_used += extent_bytes
  62 *
  63 * MAKING RESERVATIONS, FLUSHING NORMALLY (non-priority)
  64 *
  65 *   Assume we are unable to simply make the reservation because we do not have
  66 *   enough space
  67 *
  68 *   -> __reserve_bytes
  69 *     create a reserve_ticket with ->bytes set to our reservation, add it to
  70 *     the tail of space_info->tickets, kick async flush thread
  71 *
  72 *   ->handle_reserve_ticket
  73 *     wait on ticket->wait for ->bytes to be reduced to 0, or ->error to be set
  74 *     on the ticket.
  75 *
  76 *   -> btrfs_async_reclaim_metadata_space/btrfs_async_reclaim_data_space
  77 *     Flushes various things attempting to free up space.
  78 *
  79 *   -> btrfs_try_granting_tickets()
  80 *     This is called by anything that either subtracts space from
  81 *     space_info->bytes_may_use, ->bytes_pinned, etc, or adds to the
  82 *     space_info->total_bytes.  This loops through the ->priority_tickets and
  83 *     then the ->tickets list checking to see if the reservation can be
  84 *     completed.  If it can the space is added to space_info->bytes_may_use and
  85 *     the ticket is woken up.
  86 *
  87 *   -> ticket wakeup
  88 *     Check if ->bytes == 0, if it does we got our reservation and we can carry
  89 *     on, if not return the appropriate error (ENOSPC, but can be EINTR if we
  90 *     were interrupted.)
  91 *
  92 * MAKING RESERVATIONS, FLUSHING HIGH PRIORITY
  93 *
  94 *   Same as the above, except we add ourselves to the
  95 *   space_info->priority_tickets, and we do not use ticket->wait, we simply
  96 *   call flush_space() ourselves for the states that are safe for us to call
  97 *   without deadlocking and hope for the best.
  98 *
  99 * THE FLUSHING STATES
 100 *
 101 *   Generally speaking we will have two cases for each state, a "nice" state
 102 *   and a "ALL THE THINGS" state.  In btrfs we delay a lot of work in order to
 103 *   reduce the locking over head on the various trees, and even to keep from
 104 *   doing any work at all in the case of delayed refs.  Each of these delayed
 105 *   things however hold reservations, and so letting them run allows us to
 106 *   reclaim space so we can make new reservations.
 107 *
 108 *   FLUSH_DELAYED_ITEMS
 109 *     Every inode has a delayed item to update the inode.  Take a simple write
 110 *     for example, we would update the inode item at write time to update the
 111 *     mtime, and then again at finish_ordered_io() time in order to update the
 112 *     isize or bytes.  We keep these delayed items to coalesce these operations
 113 *     into a single operation done on demand.  These are an easy way to reclaim
 114 *     metadata space.
 115 *
 116 *   FLUSH_DELALLOC
 117 *     Look at the delalloc comment to get an idea of how much space is reserved
 118 *     for delayed allocation.  We can reclaim some of this space simply by
 119 *     running delalloc, but usually we need to wait for ordered extents to
 120 *     reclaim the bulk of this space.
 121 *
 122 *   FLUSH_DELAYED_REFS
 123 *     We have a block reserve for the outstanding delayed refs space, and every
 124 *     delayed ref operation holds a reservation.  Running these is a quick way
 125 *     to reclaim space, but we want to hold this until the end because COW can
 126 *     churn a lot and we can avoid making some extent tree modifications if we
 127 *     are able to delay for as long as possible.
 128 *
 129 *   ALLOC_CHUNK
 130 *     We will skip this the first time through space reservation, because of
 131 *     overcommit and we don't want to have a lot of useless metadata space when
 132 *     our worst case reservations will likely never come true.
 133 *
 134 *   RUN_DELAYED_IPUTS
 135 *     If we're freeing inodes we're likely freeing checksums, file extent
 136 *     items, and extent tree items.  Loads of space could be freed up by these
 137 *     operations, however they won't be usable until the transaction commits.
 138 *
 139 *   COMMIT_TRANS
 140 *     This will commit the transaction.  Historically we had a lot of logic
 141 *     surrounding whether or not we'd commit the transaction, but this waits born
 142 *     out of a pre-tickets era where we could end up committing the transaction
 143 *     thousands of times in a row without making progress.  Now thanks to our
 144 *     ticketing system we know if we're not making progress and can error
 145 *     everybody out after a few commits rather than burning the disk hoping for
 146 *     a different answer.
 147 *
 148 * OVERCOMMIT
 149 *
 150 *   Because we hold so many reservations for metadata we will allow you to
 151 *   reserve more space than is currently free in the currently allocate
 152 *   metadata space.  This only happens with metadata, data does not allow
 153 *   overcommitting.
 154 *
 155 *   You can see the current logic for when we allow overcommit in
 156 *   btrfs_can_overcommit(), but it only applies to unallocated space.  If there
 157 *   is no unallocated space to be had, all reservations are kept within the
 158 *   free space in the allocated metadata chunks.
 159 *
 160 *   Because of overcommitting, you generally want to use the
 161 *   btrfs_can_overcommit() logic for metadata allocations, as it does the right
 162 *   thing with or without extra unallocated space.
 163 */
 164
 165u64 __pure btrfs_space_info_used(struct btrfs_space_info *s_info,
 166			  bool may_use_included)
 167{
 168	ASSERT(s_info);
 169	return s_info->bytes_used + s_info->bytes_reserved +
 170		s_info->bytes_pinned + s_info->bytes_readonly +
 171		s_info->bytes_zone_unusable +
 172		(may_use_included ? s_info->bytes_may_use : 0);
 173}
 174
 175/*
 176 * after adding space to the filesystem, we need to clear the full flags
 177 * on all the space infos.
 178 */
 179void btrfs_clear_space_info_full(struct btrfs_fs_info *info)
 180{
 181	struct list_head *head = &info->space_info;
 182	struct btrfs_space_info *found;
 183
 184	list_for_each_entry(found, head, list)
 185		found->full = 0;
 186}
 187
 188/*
 189 * Block groups with more than this value (percents) of unusable space will be
 190 * scheduled for background reclaim.
 191 */
 192#define BTRFS_DEFAULT_ZONED_RECLAIM_THRESH			(75)
 193
 
 
 194/*
 195 * Calculate chunk size depending on volume type (regular or zoned).
 196 */
 197static u64 calc_chunk_size(const struct btrfs_fs_info *fs_info, u64 flags)
 198{
 199	if (btrfs_is_zoned(fs_info))
 200		return fs_info->zone_size;
 201
 202	ASSERT(flags & BTRFS_BLOCK_GROUP_TYPE_MASK);
 203
 204	if (flags & BTRFS_BLOCK_GROUP_DATA)
 205		return BTRFS_MAX_DATA_CHUNK_SIZE;
 206	else if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
 207		return SZ_32M;
 208
 209	/* Handle BTRFS_BLOCK_GROUP_METADATA */
 210	if (fs_info->fs_devices->total_rw_bytes > 50ULL * SZ_1G)
 211		return SZ_1G;
 212
 213	return SZ_256M;
 214}
 215
 216/*
 217 * Update default chunk size.
 218 */
 219void btrfs_update_space_info_chunk_size(struct btrfs_space_info *space_info,
 220					u64 chunk_size)
 221{
 222	WRITE_ONCE(space_info->chunk_size, chunk_size);
 223}
 224
 225static int create_space_info(struct btrfs_fs_info *info, u64 flags)
 226{
 227
 228	struct btrfs_space_info *space_info;
 229	int i;
 230	int ret;
 231
 232	space_info = kzalloc(sizeof(*space_info), GFP_NOFS);
 233	if (!space_info)
 234		return -ENOMEM;
 235
 
 236	for (i = 0; i < BTRFS_NR_RAID_TYPES; i++)
 237		INIT_LIST_HEAD(&space_info->block_groups[i]);
 238	init_rwsem(&space_info->groups_sem);
 239	spin_lock_init(&space_info->lock);
 240	space_info->flags = flags & BTRFS_BLOCK_GROUP_TYPE_MASK;
 241	space_info->force_alloc = CHUNK_ALLOC_NO_FORCE;
 242	INIT_LIST_HEAD(&space_info->ro_bgs);
 243	INIT_LIST_HEAD(&space_info->tickets);
 244	INIT_LIST_HEAD(&space_info->priority_tickets);
 245	space_info->clamp = 1;
 246	btrfs_update_space_info_chunk_size(space_info, calc_chunk_size(info, flags));
 247
 248	if (btrfs_is_zoned(info))
 249		space_info->bg_reclaim_threshold = BTRFS_DEFAULT_ZONED_RECLAIM_THRESH;
 250
 251	ret = btrfs_sysfs_add_space_info_type(info, space_info);
 252	if (ret)
 253		return ret;
 254
 255	list_add(&space_info->list, &info->space_info);
 256	if (flags & BTRFS_BLOCK_GROUP_DATA)
 257		info->data_sinfo = space_info;
 258
 259	return ret;
 260}
 261
 262int btrfs_init_space_info(struct btrfs_fs_info *fs_info)
 263{
 264	struct btrfs_super_block *disk_super;
 265	u64 features;
 266	u64 flags;
 267	int mixed = 0;
 268	int ret;
 269
 270	disk_super = fs_info->super_copy;
 271	if (!btrfs_super_root(disk_super))
 272		return -EINVAL;
 273
 274	features = btrfs_super_incompat_flags(disk_super);
 275	if (features & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS)
 276		mixed = 1;
 277
 278	flags = BTRFS_BLOCK_GROUP_SYSTEM;
 279	ret = create_space_info(fs_info, flags);
 280	if (ret)
 281		goto out;
 282
 283	if (mixed) {
 284		flags = BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA;
 285		ret = create_space_info(fs_info, flags);
 286	} else {
 287		flags = BTRFS_BLOCK_GROUP_METADATA;
 288		ret = create_space_info(fs_info, flags);
 289		if (ret)
 290			goto out;
 291
 292		flags = BTRFS_BLOCK_GROUP_DATA;
 293		ret = create_space_info(fs_info, flags);
 294	}
 295out:
 296	return ret;
 297}
 298
 299void btrfs_add_bg_to_space_info(struct btrfs_fs_info *info,
 300				struct btrfs_block_group *block_group)
 301{
 302	struct btrfs_space_info *found;
 303	int factor, index;
 304
 305	factor = btrfs_bg_type_to_factor(block_group->flags);
 306
 307	found = btrfs_find_space_info(info, block_group->flags);
 308	ASSERT(found);
 309	spin_lock(&found->lock);
 310	found->total_bytes += block_group->length;
 311	if (test_bit(BLOCK_GROUP_FLAG_ZONE_IS_ACTIVE, &block_group->runtime_flags))
 312		found->active_total_bytes += block_group->length;
 313	found->disk_total += block_group->length * factor;
 314	found->bytes_used += block_group->used;
 315	found->disk_used += block_group->used * factor;
 316	found->bytes_readonly += block_group->bytes_super;
 317	found->bytes_zone_unusable += block_group->zone_unusable;
 318	if (block_group->length > 0)
 319		found->full = 0;
 320	btrfs_try_granting_tickets(info, found);
 321	spin_unlock(&found->lock);
 322
 323	block_group->space_info = found;
 324
 325	index = btrfs_bg_flags_to_raid_index(block_group->flags);
 326	down_write(&found->groups_sem);
 327	list_add_tail(&block_group->list, &found->block_groups[index]);
 328	up_write(&found->groups_sem);
 329}
 330
 331struct btrfs_space_info *btrfs_find_space_info(struct btrfs_fs_info *info,
 332					       u64 flags)
 333{
 334	struct list_head *head = &info->space_info;
 335	struct btrfs_space_info *found;
 336
 337	flags &= BTRFS_BLOCK_GROUP_TYPE_MASK;
 338
 339	list_for_each_entry(found, head, list) {
 340		if (found->flags & flags)
 341			return found;
 342	}
 343	return NULL;
 344}
 345
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 346static u64 calc_available_free_space(struct btrfs_fs_info *fs_info,
 347			  struct btrfs_space_info *space_info,
 348			  enum btrfs_reserve_flush_enum flush)
 349{
 350	u64 profile;
 351	u64 avail;
 
 352	int factor;
 353
 354	if (space_info->flags & BTRFS_BLOCK_GROUP_SYSTEM)
 355		profile = btrfs_system_alloc_profile(fs_info);
 356	else
 357		profile = btrfs_metadata_alloc_profile(fs_info);
 358
 359	avail = atomic64_read(&fs_info->free_chunk_space);
 360
 361	/*
 362	 * If we have dup, raid1 or raid10 then only half of the free
 363	 * space is actually usable.  For raid56, the space info used
 364	 * doesn't include the parity drive, so we don't have to
 365	 * change the math
 366	 */
 367	factor = btrfs_bg_type_to_factor(profile);
 368	avail = div_u64(avail, factor);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 369
 370	/*
 371	 * If we aren't flushing all things, let us overcommit up to
 372	 * 1/2th of the space. If we can flush, don't let us overcommit
 373	 * too much, let it overcommit up to 1/8 of the space.
 374	 */
 375	if (flush == BTRFS_RESERVE_FLUSH_ALL)
 376		avail >>= 3;
 377	else
 378		avail >>= 1;
 379	return avail;
 380}
 381
 382static inline u64 writable_total_bytes(struct btrfs_fs_info *fs_info,
 383				       struct btrfs_space_info *space_info)
 384{
 385	/*
 386	 * On regular filesystem, all total_bytes are always writable. On zoned
 387	 * filesystem, there may be a limitation imposed by max_active_zones.
 388	 * For metadata allocation, we cannot finish an existing active block
 389	 * group to avoid a deadlock. Thus, we need to consider only the active
 390	 * groups to be writable for metadata space.
 391	 */
 392	if (!btrfs_is_zoned(fs_info) || (space_info->flags & BTRFS_BLOCK_GROUP_DATA))
 393		return space_info->total_bytes;
 394
 395	return space_info->active_total_bytes;
 396}
 397
 398int btrfs_can_overcommit(struct btrfs_fs_info *fs_info,
 399			 struct btrfs_space_info *space_info, u64 bytes,
 400			 enum btrfs_reserve_flush_enum flush)
 401{
 402	u64 avail;
 403	u64 used;
 404
 405	/* Don't overcommit when in mixed mode */
 406	if (space_info->flags & BTRFS_BLOCK_GROUP_DATA)
 407		return 0;
 408
 409	used = btrfs_space_info_used(space_info, true);
 410	if (test_bit(BTRFS_FS_NO_OVERCOMMIT, &fs_info->flags) &&
 411	    (space_info->flags & BTRFS_BLOCK_GROUP_METADATA))
 412		avail = 0;
 413	else
 414		avail = calc_available_free_space(fs_info, space_info, flush);
 415
 416	if (used + bytes < writable_total_bytes(fs_info, space_info) + avail)
 417		return 1;
 418	return 0;
 419}
 420
 421static void remove_ticket(struct btrfs_space_info *space_info,
 422			  struct reserve_ticket *ticket)
 423{
 424	if (!list_empty(&ticket->list)) {
 425		list_del_init(&ticket->list);
 426		ASSERT(space_info->reclaim_size >= ticket->bytes);
 427		space_info->reclaim_size -= ticket->bytes;
 428	}
 429}
 430
 431/*
 432 * This is for space we already have accounted in space_info->bytes_may_use, so
 433 * basically when we're returning space from block_rsv's.
 434 */
 435void btrfs_try_granting_tickets(struct btrfs_fs_info *fs_info,
 436				struct btrfs_space_info *space_info)
 437{
 438	struct list_head *head;
 439	enum btrfs_reserve_flush_enum flush = BTRFS_RESERVE_NO_FLUSH;
 440
 441	lockdep_assert_held(&space_info->lock);
 442
 443	head = &space_info->priority_tickets;
 444again:
 445	while (!list_empty(head)) {
 446		struct reserve_ticket *ticket;
 447		u64 used = btrfs_space_info_used(space_info, true);
 448
 449		ticket = list_first_entry(head, struct reserve_ticket, list);
 450
 451		/* Check and see if our ticket can be satisfied now. */
 452		if ((used + ticket->bytes <= writable_total_bytes(fs_info, space_info)) ||
 453		    btrfs_can_overcommit(fs_info, space_info, ticket->bytes,
 454					 flush)) {
 455			btrfs_space_info_update_bytes_may_use(fs_info,
 456							      space_info,
 457							      ticket->bytes);
 458			remove_ticket(space_info, ticket);
 459			ticket->bytes = 0;
 460			space_info->tickets_id++;
 461			wake_up(&ticket->wait);
 462		} else {
 463			break;
 464		}
 465	}
 466
 467	if (head == &space_info->priority_tickets) {
 468		head = &space_info->tickets;
 469		flush = BTRFS_RESERVE_FLUSH_ALL;
 470		goto again;
 471	}
 472}
 473
 474#define DUMP_BLOCK_RSV(fs_info, rsv_name)				\
 475do {									\
 476	struct btrfs_block_rsv *__rsv = &(fs_info)->rsv_name;		\
 477	spin_lock(&__rsv->lock);					\
 478	btrfs_info(fs_info, #rsv_name ": size %llu reserved %llu",	\
 479		   __rsv->size, __rsv->reserved);			\
 480	spin_unlock(&__rsv->lock);					\
 481} while (0)
 482
 483static const char *space_info_flag_to_str(const struct btrfs_space_info *space_info)
 484{
 485	switch (space_info->flags) {
 486	case BTRFS_BLOCK_GROUP_SYSTEM:
 487		return "SYSTEM";
 488	case BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA:
 489		return "DATA+METADATA";
 490	case BTRFS_BLOCK_GROUP_DATA:
 491		return "DATA";
 492	case BTRFS_BLOCK_GROUP_METADATA:
 493		return "METADATA";
 494	default:
 495		return "UNKNOWN";
 496	}
 497}
 498
 499static void dump_global_block_rsv(struct btrfs_fs_info *fs_info)
 500{
 501	DUMP_BLOCK_RSV(fs_info, global_block_rsv);
 502	DUMP_BLOCK_RSV(fs_info, trans_block_rsv);
 503	DUMP_BLOCK_RSV(fs_info, chunk_block_rsv);
 504	DUMP_BLOCK_RSV(fs_info, delayed_block_rsv);
 505	DUMP_BLOCK_RSV(fs_info, delayed_refs_rsv);
 506}
 507
 508static void __btrfs_dump_space_info(struct btrfs_fs_info *fs_info,
 509				    struct btrfs_space_info *info)
 510{
 511	const char *flag_str = space_info_flag_to_str(info);
 512	lockdep_assert_held(&info->lock);
 513
 514	/* The free space could be negative in case of overcommit */
 515	btrfs_info(fs_info, "space_info %s has %lld free, is %sfull",
 516		   flag_str,
 517		   (s64)(info->total_bytes - btrfs_space_info_used(info, true)),
 518		   info->full ? "" : "not ");
 519	btrfs_info(fs_info,
 520"space_info total=%llu, used=%llu, pinned=%llu, reserved=%llu, may_use=%llu, readonly=%llu zone_unusable=%llu",
 521		info->total_bytes, info->bytes_used, info->bytes_pinned,
 522		info->bytes_reserved, info->bytes_may_use,
 523		info->bytes_readonly, info->bytes_zone_unusable);
 524}
 525
 526void btrfs_dump_space_info(struct btrfs_fs_info *fs_info,
 527			   struct btrfs_space_info *info, u64 bytes,
 528			   int dump_block_groups)
 529{
 530	struct btrfs_block_group *cache;
 
 531	int index = 0;
 532
 533	spin_lock(&info->lock);
 534	__btrfs_dump_space_info(fs_info, info);
 535	dump_global_block_rsv(fs_info);
 536	spin_unlock(&info->lock);
 537
 538	if (!dump_block_groups)
 539		return;
 540
 541	down_read(&info->groups_sem);
 542again:
 543	list_for_each_entry(cache, &info->block_groups[index], list) {
 
 
 544		spin_lock(&cache->lock);
 
 
 545		btrfs_info(fs_info,
 546			"block group %llu has %llu bytes, %llu used %llu pinned %llu reserved %llu zone_unusable %s",
 547			cache->start, cache->length, cache->used, cache->pinned,
 548			cache->reserved, cache->zone_unusable,
 549			cache->ro ? "[readonly]" : "");
 
 550		spin_unlock(&cache->lock);
 551		btrfs_dump_free_space(cache, bytes);
 
 552	}
 553	if (++index < BTRFS_NR_RAID_TYPES)
 554		goto again;
 555	up_read(&info->groups_sem);
 
 
 556}
 557
 558static inline u64 calc_reclaim_items_nr(struct btrfs_fs_info *fs_info,
 559					u64 to_reclaim)
 560{
 561	u64 bytes;
 562	u64 nr;
 563
 564	bytes = btrfs_calc_insert_metadata_size(fs_info, 1);
 565	nr = div64_u64(to_reclaim, bytes);
 566	if (!nr)
 567		nr = 1;
 568	return nr;
 569}
 570
 571#define EXTENT_SIZE_PER_ITEM	SZ_256K
 572
 573/*
 574 * shrink metadata reservation for delalloc
 575 */
 576static void shrink_delalloc(struct btrfs_fs_info *fs_info,
 577			    struct btrfs_space_info *space_info,
 578			    u64 to_reclaim, bool wait_ordered,
 579			    bool for_preempt)
 580{
 581	struct btrfs_trans_handle *trans;
 582	u64 delalloc_bytes;
 583	u64 ordered_bytes;
 584	u64 items;
 585	long time_left;
 586	int loops;
 587
 588	delalloc_bytes = percpu_counter_sum_positive(&fs_info->delalloc_bytes);
 589	ordered_bytes = percpu_counter_sum_positive(&fs_info->ordered_bytes);
 590	if (delalloc_bytes == 0 && ordered_bytes == 0)
 591		return;
 592
 593	/* Calc the number of the pages we need flush for space reservation */
 594	if (to_reclaim == U64_MAX) {
 595		items = U64_MAX;
 596	} else {
 597		/*
 598		 * to_reclaim is set to however much metadata we need to
 599		 * reclaim, but reclaiming that much data doesn't really track
 600		 * exactly.  What we really want to do is reclaim full inode's
 601		 * worth of reservations, however that's not available to us
 602		 * here.  We will take a fraction of the delalloc bytes for our
 603		 * flushing loops and hope for the best.  Delalloc will expand
 604		 * the amount we write to cover an entire dirty extent, which
 605		 * will reclaim the metadata reservation for that range.  If
 606		 * it's not enough subsequent flush stages will be more
 607		 * aggressive.
 608		 */
 609		to_reclaim = max(to_reclaim, delalloc_bytes >> 3);
 610		items = calc_reclaim_items_nr(fs_info, to_reclaim) * 2;
 611	}
 612
 613	trans = current->journal_info;
 614
 615	/*
 616	 * If we are doing more ordered than delalloc we need to just wait on
 617	 * ordered extents, otherwise we'll waste time trying to flush delalloc
 618	 * that likely won't give us the space back we need.
 619	 */
 620	if (ordered_bytes > delalloc_bytes && !for_preempt)
 621		wait_ordered = true;
 622
 623	loops = 0;
 624	while ((delalloc_bytes || ordered_bytes) && loops < 3) {
 625		u64 temp = min(delalloc_bytes, to_reclaim) >> PAGE_SHIFT;
 626		long nr_pages = min_t(u64, temp, LONG_MAX);
 627		int async_pages;
 628
 629		btrfs_start_delalloc_roots(fs_info, nr_pages, true);
 630
 631		/*
 632		 * We need to make sure any outstanding async pages are now
 633		 * processed before we continue.  This is because things like
 634		 * sync_inode() try to be smart and skip writing if the inode is
 635		 * marked clean.  We don't use filemap_fwrite for flushing
 636		 * because we want to control how many pages we write out at a
 637		 * time, thus this is the only safe way to make sure we've
 638		 * waited for outstanding compressed workers to have started
 639		 * their jobs and thus have ordered extents set up properly.
 640		 *
 641		 * This exists because we do not want to wait for each
 642		 * individual inode to finish its async work, we simply want to
 643		 * start the IO on everybody, and then come back here and wait
 644		 * for all of the async work to catch up.  Once we're done with
 645		 * that we know we'll have ordered extents for everything and we
 646		 * can decide if we wait for that or not.
 647		 *
 648		 * If we choose to replace this in the future, make absolutely
 649		 * sure that the proper waiting is being done in the async case,
 650		 * as there have been bugs in that area before.
 651		 */
 652		async_pages = atomic_read(&fs_info->async_delalloc_pages);
 653		if (!async_pages)
 654			goto skip_async;
 655
 656		/*
 657		 * We don't want to wait forever, if we wrote less pages in this
 658		 * loop than we have outstanding, only wait for that number of
 659		 * pages, otherwise we can wait for all async pages to finish
 660		 * before continuing.
 661		 */
 662		if (async_pages > nr_pages)
 663			async_pages -= nr_pages;
 664		else
 665			async_pages = 0;
 666		wait_event(fs_info->async_submit_wait,
 667			   atomic_read(&fs_info->async_delalloc_pages) <=
 668			   async_pages);
 669skip_async:
 670		loops++;
 671		if (wait_ordered && !trans) {
 672			btrfs_wait_ordered_roots(fs_info, items, 0, (u64)-1);
 673		} else {
 674			time_left = schedule_timeout_killable(1);
 675			if (time_left)
 676				break;
 677		}
 678
 679		/*
 680		 * If we are for preemption we just want a one-shot of delalloc
 681		 * flushing so we can stop flushing if we decide we don't need
 682		 * to anymore.
 683		 */
 684		if (for_preempt)
 685			break;
 686
 687		spin_lock(&space_info->lock);
 688		if (list_empty(&space_info->tickets) &&
 689		    list_empty(&space_info->priority_tickets)) {
 690			spin_unlock(&space_info->lock);
 691			break;
 692		}
 693		spin_unlock(&space_info->lock);
 694
 695		delalloc_bytes = percpu_counter_sum_positive(
 696						&fs_info->delalloc_bytes);
 697		ordered_bytes = percpu_counter_sum_positive(
 698						&fs_info->ordered_bytes);
 699	}
 700}
 701
 702/*
 703 * Try to flush some data based on policy set by @state. This is only advisory
 704 * and may fail for various reasons. The caller is supposed to examine the
 705 * state of @space_info to detect the outcome.
 706 */
 707static void flush_space(struct btrfs_fs_info *fs_info,
 708		       struct btrfs_space_info *space_info, u64 num_bytes,
 709		       enum btrfs_flush_state state, bool for_preempt)
 710{
 711	struct btrfs_root *root = fs_info->tree_root;
 712	struct btrfs_trans_handle *trans;
 713	int nr;
 714	int ret = 0;
 715
 716	switch (state) {
 717	case FLUSH_DELAYED_ITEMS_NR:
 718	case FLUSH_DELAYED_ITEMS:
 719		if (state == FLUSH_DELAYED_ITEMS_NR)
 720			nr = calc_reclaim_items_nr(fs_info, num_bytes) * 2;
 721		else
 722			nr = -1;
 723
 724		trans = btrfs_join_transaction(root);
 725		if (IS_ERR(trans)) {
 726			ret = PTR_ERR(trans);
 
 
 727			break;
 728		}
 729		ret = btrfs_run_delayed_items_nr(trans, nr);
 730		btrfs_end_transaction(trans);
 731		break;
 732	case FLUSH_DELALLOC:
 733	case FLUSH_DELALLOC_WAIT:
 734	case FLUSH_DELALLOC_FULL:
 735		if (state == FLUSH_DELALLOC_FULL)
 736			num_bytes = U64_MAX;
 737		shrink_delalloc(fs_info, space_info, num_bytes,
 738				state != FLUSH_DELALLOC, for_preempt);
 739		break;
 740	case FLUSH_DELAYED_REFS_NR:
 741	case FLUSH_DELAYED_REFS:
 742		trans = btrfs_join_transaction(root);
 743		if (IS_ERR(trans)) {
 744			ret = PTR_ERR(trans);
 
 
 745			break;
 746		}
 747		if (state == FLUSH_DELAYED_REFS_NR)
 748			nr = calc_reclaim_items_nr(fs_info, num_bytes);
 749		else
 750			nr = 0;
 751		btrfs_run_delayed_refs(trans, nr);
 752		btrfs_end_transaction(trans);
 753		break;
 754	case ALLOC_CHUNK:
 755	case ALLOC_CHUNK_FORCE:
 756		/*
 757		 * For metadata space on zoned filesystem, reaching here means we
 758		 * don't have enough space left in active_total_bytes. Try to
 759		 * activate a block group first, because we may have inactive
 760		 * block group already allocated.
 761		 */
 762		ret = btrfs_zoned_activate_one_bg(fs_info, space_info, false);
 763		if (ret < 0)
 764			break;
 765		else if (ret == 1)
 766			break;
 767
 768		trans = btrfs_join_transaction(root);
 769		if (IS_ERR(trans)) {
 770			ret = PTR_ERR(trans);
 771			break;
 772		}
 773		ret = btrfs_chunk_alloc(trans,
 774				btrfs_get_alloc_profile(fs_info, space_info->flags),
 775				(state == ALLOC_CHUNK) ? CHUNK_ALLOC_NO_FORCE :
 776					CHUNK_ALLOC_FORCE);
 777		btrfs_end_transaction(trans);
 778
 779		/*
 780		 * For metadata space on zoned filesystem, allocating a new chunk
 781		 * is not enough. We still need to activate the block * group.
 782		 * Active the newly allocated block group by (maybe) finishing
 783		 * a block group.
 784		 */
 785		if (ret == 1) {
 786			ret = btrfs_zoned_activate_one_bg(fs_info, space_info, true);
 787			/*
 788			 * Revert to the original ret regardless we could finish
 789			 * one block group or not.
 790			 */
 791			if (ret >= 0)
 792				ret = 1;
 793		}
 794
 795		if (ret > 0 || ret == -ENOSPC)
 796			ret = 0;
 797		break;
 798	case RUN_DELAYED_IPUTS:
 799		/*
 800		 * If we have pending delayed iputs then we could free up a
 801		 * bunch of pinned space, so make sure we run the iputs before
 802		 * we do our pinned bytes check below.
 803		 */
 804		btrfs_run_delayed_iputs(fs_info);
 805		btrfs_wait_on_delayed_iputs(fs_info);
 806		break;
 807	case COMMIT_TRANS:
 808		ASSERT(current->journal_info == NULL);
 809		trans = btrfs_join_transaction(root);
 810		if (IS_ERR(trans)) {
 811			ret = PTR_ERR(trans);
 812			break;
 813		}
 814		ret = btrfs_commit_transaction(trans);
 
 
 815		break;
 816	default:
 817		ret = -ENOSPC;
 818		break;
 819	}
 820
 821	trace_btrfs_flush_space(fs_info, space_info->flags, num_bytes, state,
 822				ret, for_preempt);
 823	return;
 824}
 825
 826static inline u64
 827btrfs_calc_reclaim_metadata_size(struct btrfs_fs_info *fs_info,
 828				 struct btrfs_space_info *space_info)
 829{
 830	u64 used;
 831	u64 avail;
 832	u64 total;
 833	u64 to_reclaim = space_info->reclaim_size;
 834
 835	lockdep_assert_held(&space_info->lock);
 836
 837	avail = calc_available_free_space(fs_info, space_info,
 838					  BTRFS_RESERVE_FLUSH_ALL);
 839	used = btrfs_space_info_used(space_info, true);
 840
 841	/*
 842	 * We may be flushing because suddenly we have less space than we had
 843	 * before, and now we're well over-committed based on our current free
 844	 * space.  If that's the case add in our overage so we make sure to put
 845	 * appropriate pressure on the flushing state machine.
 846	 */
 847	total = writable_total_bytes(fs_info, space_info);
 848	if (total + avail < used)
 849		to_reclaim += used - (total + avail);
 850
 851	return to_reclaim;
 852}
 853
 854static bool need_preemptive_reclaim(struct btrfs_fs_info *fs_info,
 855				    struct btrfs_space_info *space_info)
 856{
 857	u64 global_rsv_size = fs_info->global_block_rsv.reserved;
 858	u64 ordered, delalloc;
 859	u64 total = writable_total_bytes(fs_info, space_info);
 860	u64 thresh;
 861	u64 used;
 862
 863	thresh = mult_perc(total, 90);
 864
 865	lockdep_assert_held(&space_info->lock);
 866
 867	/* If we're just plain full then async reclaim just slows us down. */
 868	if ((space_info->bytes_used + space_info->bytes_reserved +
 869	     global_rsv_size) >= thresh)
 870		return false;
 871
 872	used = space_info->bytes_may_use + space_info->bytes_pinned;
 873
 874	/* The total flushable belongs to the global rsv, don't flush. */
 875	if (global_rsv_size >= used)
 876		return false;
 877
 878	/*
 879	 * 128MiB is 1/4 of the maximum global rsv size.  If we have less than
 880	 * that devoted to other reservations then there's no sense in flushing,
 881	 * we don't have a lot of things that need flushing.
 882	 */
 883	if (used - global_rsv_size <= SZ_128M)
 884		return false;
 885
 886	/*
 887	 * We have tickets queued, bail so we don't compete with the async
 888	 * flushers.
 889	 */
 890	if (space_info->reclaim_size)
 891		return false;
 892
 893	/*
 894	 * If we have over half of the free space occupied by reservations or
 895	 * pinned then we want to start flushing.
 896	 *
 897	 * We do not do the traditional thing here, which is to say
 898	 *
 899	 *   if (used >= ((total_bytes + avail) / 2))
 900	 *     return 1;
 901	 *
 902	 * because this doesn't quite work how we want.  If we had more than 50%
 903	 * of the space_info used by bytes_used and we had 0 available we'd just
 904	 * constantly run the background flusher.  Instead we want it to kick in
 905	 * if our reclaimable space exceeds our clamped free space.
 906	 *
 907	 * Our clamping range is 2^1 -> 2^8.  Practically speaking that means
 908	 * the following:
 909	 *
 910	 * Amount of RAM        Minimum threshold       Maximum threshold
 911	 *
 912	 *        256GiB                     1GiB                  128GiB
 913	 *        128GiB                   512MiB                   64GiB
 914	 *         64GiB                   256MiB                   32GiB
 915	 *         32GiB                   128MiB                   16GiB
 916	 *         16GiB                    64MiB                    8GiB
 917	 *
 918	 * These are the range our thresholds will fall in, corresponding to how
 919	 * much delalloc we need for the background flusher to kick in.
 920	 */
 921
 922	thresh = calc_available_free_space(fs_info, space_info,
 923					   BTRFS_RESERVE_FLUSH_ALL);
 924	used = space_info->bytes_used + space_info->bytes_reserved +
 925	       space_info->bytes_readonly + global_rsv_size;
 926	if (used < total)
 927		thresh += total - used;
 928	thresh >>= space_info->clamp;
 929
 930	used = space_info->bytes_pinned;
 931
 932	/*
 933	 * If we have more ordered bytes than delalloc bytes then we're either
 934	 * doing a lot of DIO, or we simply don't have a lot of delalloc waiting
 935	 * around.  Preemptive flushing is only useful in that it can free up
 936	 * space before tickets need to wait for things to finish.  In the case
 937	 * of ordered extents, preemptively waiting on ordered extents gets us
 938	 * nothing, if our reservations are tied up in ordered extents we'll
 939	 * simply have to slow down writers by forcing them to wait on ordered
 940	 * extents.
 941	 *
 942	 * In the case that ordered is larger than delalloc, only include the
 943	 * block reserves that we would actually be able to directly reclaim
 944	 * from.  In this case if we're heavy on metadata operations this will
 945	 * clearly be heavy enough to warrant preemptive flushing.  In the case
 946	 * of heavy DIO or ordered reservations, preemptive flushing will just
 947	 * waste time and cause us to slow down.
 948	 *
 949	 * We want to make sure we truly are maxed out on ordered however, so
 950	 * cut ordered in half, and if it's still higher than delalloc then we
 951	 * can keep flushing.  This is to avoid the case where we start
 952	 * flushing, and now delalloc == ordered and we stop preemptively
 953	 * flushing when we could still have several gigs of delalloc to flush.
 954	 */
 955	ordered = percpu_counter_read_positive(&fs_info->ordered_bytes) >> 1;
 956	delalloc = percpu_counter_read_positive(&fs_info->delalloc_bytes);
 957	if (ordered >= delalloc)
 958		used += fs_info->delayed_refs_rsv.reserved +
 959			fs_info->delayed_block_rsv.reserved;
 960	else
 961		used += space_info->bytes_may_use - global_rsv_size;
 962
 963	return (used >= thresh && !btrfs_fs_closing(fs_info) &&
 964		!test_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state));
 965}
 966
 967static bool steal_from_global_rsv(struct btrfs_fs_info *fs_info,
 968				  struct btrfs_space_info *space_info,
 969				  struct reserve_ticket *ticket)
 970{
 971	struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
 972	u64 min_bytes;
 973
 974	if (!ticket->steal)
 975		return false;
 976
 977	if (global_rsv->space_info != space_info)
 978		return false;
 979
 980	spin_lock(&global_rsv->lock);
 981	min_bytes = mult_perc(global_rsv->size, 10);
 982	if (global_rsv->reserved < min_bytes + ticket->bytes) {
 983		spin_unlock(&global_rsv->lock);
 984		return false;
 985	}
 986	global_rsv->reserved -= ticket->bytes;
 987	remove_ticket(space_info, ticket);
 988	ticket->bytes = 0;
 989	wake_up(&ticket->wait);
 990	space_info->tickets_id++;
 991	if (global_rsv->reserved < global_rsv->size)
 992		global_rsv->full = 0;
 993	spin_unlock(&global_rsv->lock);
 994
 995	return true;
 996}
 997
 998/*
 999 * maybe_fail_all_tickets - we've exhausted our flushing, start failing tickets
 
1000 * @fs_info - fs_info for this fs
1001 * @space_info - the space info we were flushing
1002 *
1003 * We call this when we've exhausted our flushing ability and haven't made
1004 * progress in satisfying tickets.  The reservation code handles tickets in
1005 * order, so if there is a large ticket first and then smaller ones we could
1006 * very well satisfy the smaller tickets.  This will attempt to wake up any
1007 * tickets in the list to catch this case.
1008 *
1009 * This function returns true if it was able to make progress by clearing out
1010 * other tickets, or if it stumbles across a ticket that was smaller than the
1011 * first ticket.
1012 */
1013static bool maybe_fail_all_tickets(struct btrfs_fs_info *fs_info,
1014				   struct btrfs_space_info *space_info)
1015{
1016	struct reserve_ticket *ticket;
1017	u64 tickets_id = space_info->tickets_id;
1018	const bool aborted = BTRFS_FS_ERROR(fs_info);
1019
1020	trace_btrfs_fail_all_tickets(fs_info, space_info);
1021
1022	if (btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
1023		btrfs_info(fs_info, "cannot satisfy tickets, dumping space info");
1024		__btrfs_dump_space_info(fs_info, space_info);
1025	}
1026
1027	while (!list_empty(&space_info->tickets) &&
1028	       tickets_id == space_info->tickets_id) {
1029		ticket = list_first_entry(&space_info->tickets,
1030					  struct reserve_ticket, list);
1031
1032		if (!aborted && steal_from_global_rsv(fs_info, space_info, ticket))
1033			return true;
1034
1035		if (!aborted && btrfs_test_opt(fs_info, ENOSPC_DEBUG))
1036			btrfs_info(fs_info, "failing ticket with %llu bytes",
1037				   ticket->bytes);
1038
1039		remove_ticket(space_info, ticket);
1040		if (aborted)
1041			ticket->error = -EIO;
1042		else
1043			ticket->error = -ENOSPC;
1044		wake_up(&ticket->wait);
1045
1046		/*
1047		 * We're just throwing tickets away, so more flushing may not
1048		 * trip over btrfs_try_granting_tickets, so we need to call it
1049		 * here to see if we can make progress with the next ticket in
1050		 * the list.
1051		 */
1052		if (!aborted)
1053			btrfs_try_granting_tickets(fs_info, space_info);
1054	}
1055	return (tickets_id != space_info->tickets_id);
1056}
1057
1058/*
1059 * This is for normal flushers, we can wait all goddamned day if we want to.  We
1060 * will loop and continuously try to flush as long as we are making progress.
1061 * We count progress as clearing off tickets each time we have to loop.
1062 */
1063static void btrfs_async_reclaim_metadata_space(struct work_struct *work)
1064{
1065	struct btrfs_fs_info *fs_info;
1066	struct btrfs_space_info *space_info;
1067	u64 to_reclaim;
1068	enum btrfs_flush_state flush_state;
1069	int commit_cycles = 0;
1070	u64 last_tickets_id;
1071
1072	fs_info = container_of(work, struct btrfs_fs_info, async_reclaim_work);
1073	space_info = btrfs_find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
1074
1075	spin_lock(&space_info->lock);
1076	to_reclaim = btrfs_calc_reclaim_metadata_size(fs_info, space_info);
1077	if (!to_reclaim) {
1078		space_info->flush = 0;
1079		spin_unlock(&space_info->lock);
1080		return;
1081	}
1082	last_tickets_id = space_info->tickets_id;
1083	spin_unlock(&space_info->lock);
1084
1085	flush_state = FLUSH_DELAYED_ITEMS_NR;
1086	do {
1087		flush_space(fs_info, space_info, to_reclaim, flush_state, false);
1088		spin_lock(&space_info->lock);
1089		if (list_empty(&space_info->tickets)) {
1090			space_info->flush = 0;
1091			spin_unlock(&space_info->lock);
1092			return;
1093		}
1094		to_reclaim = btrfs_calc_reclaim_metadata_size(fs_info,
1095							      space_info);
1096		if (last_tickets_id == space_info->tickets_id) {
1097			flush_state++;
1098		} else {
1099			last_tickets_id = space_info->tickets_id;
1100			flush_state = FLUSH_DELAYED_ITEMS_NR;
1101			if (commit_cycles)
1102				commit_cycles--;
1103		}
1104
1105		/*
1106		 * We do not want to empty the system of delalloc unless we're
1107		 * under heavy pressure, so allow one trip through the flushing
1108		 * logic before we start doing a FLUSH_DELALLOC_FULL.
1109		 */
1110		if (flush_state == FLUSH_DELALLOC_FULL && !commit_cycles)
1111			flush_state++;
1112
1113		/*
1114		 * We don't want to force a chunk allocation until we've tried
1115		 * pretty hard to reclaim space.  Think of the case where we
1116		 * freed up a bunch of space and so have a lot of pinned space
1117		 * to reclaim.  We would rather use that than possibly create a
1118		 * underutilized metadata chunk.  So if this is our first run
1119		 * through the flushing state machine skip ALLOC_CHUNK_FORCE and
1120		 * commit the transaction.  If nothing has changed the next go
1121		 * around then we can force a chunk allocation.
1122		 */
1123		if (flush_state == ALLOC_CHUNK_FORCE && !commit_cycles)
1124			flush_state++;
1125
1126		if (flush_state > COMMIT_TRANS) {
1127			commit_cycles++;
1128			if (commit_cycles > 2) {
1129				if (maybe_fail_all_tickets(fs_info, space_info)) {
1130					flush_state = FLUSH_DELAYED_ITEMS_NR;
1131					commit_cycles--;
1132				} else {
1133					space_info->flush = 0;
1134				}
1135			} else {
1136				flush_state = FLUSH_DELAYED_ITEMS_NR;
1137			}
1138		}
1139		spin_unlock(&space_info->lock);
1140	} while (flush_state <= COMMIT_TRANS);
1141}
1142
1143/*
1144 * This handles pre-flushing of metadata space before we get to the point that
1145 * we need to start blocking threads on tickets.  The logic here is different
1146 * from the other flush paths because it doesn't rely on tickets to tell us how
1147 * much we need to flush, instead it attempts to keep us below the 80% full
1148 * watermark of space by flushing whichever reservation pool is currently the
1149 * largest.
1150 */
1151static void btrfs_preempt_reclaim_metadata_space(struct work_struct *work)
1152{
1153	struct btrfs_fs_info *fs_info;
1154	struct btrfs_space_info *space_info;
1155	struct btrfs_block_rsv *delayed_block_rsv;
1156	struct btrfs_block_rsv *delayed_refs_rsv;
1157	struct btrfs_block_rsv *global_rsv;
1158	struct btrfs_block_rsv *trans_rsv;
1159	int loops = 0;
1160
1161	fs_info = container_of(work, struct btrfs_fs_info,
1162			       preempt_reclaim_work);
1163	space_info = btrfs_find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
1164	delayed_block_rsv = &fs_info->delayed_block_rsv;
1165	delayed_refs_rsv = &fs_info->delayed_refs_rsv;
1166	global_rsv = &fs_info->global_block_rsv;
1167	trans_rsv = &fs_info->trans_block_rsv;
1168
1169	spin_lock(&space_info->lock);
1170	while (need_preemptive_reclaim(fs_info, space_info)) {
1171		enum btrfs_flush_state flush;
1172		u64 delalloc_size = 0;
1173		u64 to_reclaim, block_rsv_size;
1174		u64 global_rsv_size = global_rsv->reserved;
1175
1176		loops++;
1177
1178		/*
1179		 * We don't have a precise counter for the metadata being
1180		 * reserved for delalloc, so we'll approximate it by subtracting
1181		 * out the block rsv's space from the bytes_may_use.  If that
1182		 * amount is higher than the individual reserves, then we can
1183		 * assume it's tied up in delalloc reservations.
1184		 */
1185		block_rsv_size = global_rsv_size +
1186			delayed_block_rsv->reserved +
1187			delayed_refs_rsv->reserved +
1188			trans_rsv->reserved;
1189		if (block_rsv_size < space_info->bytes_may_use)
1190			delalloc_size = space_info->bytes_may_use - block_rsv_size;
1191
1192		/*
1193		 * We don't want to include the global_rsv in our calculation,
1194		 * because that's space we can't touch.  Subtract it from the
1195		 * block_rsv_size for the next checks.
1196		 */
1197		block_rsv_size -= global_rsv_size;
1198
1199		/*
1200		 * We really want to avoid flushing delalloc too much, as it
1201		 * could result in poor allocation patterns, so only flush it if
1202		 * it's larger than the rest of the pools combined.
1203		 */
1204		if (delalloc_size > block_rsv_size) {
1205			to_reclaim = delalloc_size;
1206			flush = FLUSH_DELALLOC;
1207		} else if (space_info->bytes_pinned >
1208			   (delayed_block_rsv->reserved +
1209			    delayed_refs_rsv->reserved)) {
1210			to_reclaim = space_info->bytes_pinned;
1211			flush = COMMIT_TRANS;
1212		} else if (delayed_block_rsv->reserved >
1213			   delayed_refs_rsv->reserved) {
1214			to_reclaim = delayed_block_rsv->reserved;
1215			flush = FLUSH_DELAYED_ITEMS_NR;
1216		} else {
1217			to_reclaim = delayed_refs_rsv->reserved;
1218			flush = FLUSH_DELAYED_REFS_NR;
1219		}
1220
1221		spin_unlock(&space_info->lock);
1222
1223		/*
1224		 * We don't want to reclaim everything, just a portion, so scale
1225		 * down the to_reclaim by 1/4.  If it takes us down to 0,
1226		 * reclaim 1 items worth.
1227		 */
1228		to_reclaim >>= 2;
1229		if (!to_reclaim)
1230			to_reclaim = btrfs_calc_insert_metadata_size(fs_info, 1);
1231		flush_space(fs_info, space_info, to_reclaim, flush, true);
1232		cond_resched();
1233		spin_lock(&space_info->lock);
1234	}
1235
1236	/* We only went through once, back off our clamping. */
1237	if (loops == 1 && !space_info->reclaim_size)
1238		space_info->clamp = max(1, space_info->clamp - 1);
1239	trace_btrfs_done_preemptive_reclaim(fs_info, space_info);
1240	spin_unlock(&space_info->lock);
1241}
1242
1243/*
1244 * FLUSH_DELALLOC_WAIT:
1245 *   Space is freed from flushing delalloc in one of two ways.
1246 *
1247 *   1) compression is on and we allocate less space than we reserved
1248 *   2) we are overwriting existing space
1249 *
1250 *   For #1 that extra space is reclaimed as soon as the delalloc pages are
1251 *   COWed, by way of btrfs_add_reserved_bytes() which adds the actual extent
1252 *   length to ->bytes_reserved, and subtracts the reserved space from
1253 *   ->bytes_may_use.
1254 *
1255 *   For #2 this is trickier.  Once the ordered extent runs we will drop the
1256 *   extent in the range we are overwriting, which creates a delayed ref for
1257 *   that freed extent.  This however is not reclaimed until the transaction
1258 *   commits, thus the next stages.
1259 *
1260 * RUN_DELAYED_IPUTS
1261 *   If we are freeing inodes, we want to make sure all delayed iputs have
1262 *   completed, because they could have been on an inode with i_nlink == 0, and
1263 *   thus have been truncated and freed up space.  But again this space is not
1264 *   immediately re-usable, it comes in the form of a delayed ref, which must be
1265 *   run and then the transaction must be committed.
1266 *
1267 * COMMIT_TRANS
1268 *   This is where we reclaim all of the pinned space generated by running the
1269 *   iputs
1270 *
1271 * ALLOC_CHUNK_FORCE
1272 *   For data we start with alloc chunk force, however we could have been full
1273 *   before, and then the transaction commit could have freed new block groups,
1274 *   so if we now have space to allocate do the force chunk allocation.
1275 */
1276static const enum btrfs_flush_state data_flush_states[] = {
1277	FLUSH_DELALLOC_FULL,
1278	RUN_DELAYED_IPUTS,
1279	COMMIT_TRANS,
1280	ALLOC_CHUNK_FORCE,
1281};
1282
1283static void btrfs_async_reclaim_data_space(struct work_struct *work)
1284{
1285	struct btrfs_fs_info *fs_info;
1286	struct btrfs_space_info *space_info;
1287	u64 last_tickets_id;
1288	enum btrfs_flush_state flush_state = 0;
1289
1290	fs_info = container_of(work, struct btrfs_fs_info, async_data_reclaim_work);
1291	space_info = fs_info->data_sinfo;
1292
1293	spin_lock(&space_info->lock);
1294	if (list_empty(&space_info->tickets)) {
1295		space_info->flush = 0;
1296		spin_unlock(&space_info->lock);
1297		return;
1298	}
1299	last_tickets_id = space_info->tickets_id;
1300	spin_unlock(&space_info->lock);
1301
1302	while (!space_info->full) {
1303		flush_space(fs_info, space_info, U64_MAX, ALLOC_CHUNK_FORCE, false);
1304		spin_lock(&space_info->lock);
1305		if (list_empty(&space_info->tickets)) {
1306			space_info->flush = 0;
1307			spin_unlock(&space_info->lock);
1308			return;
1309		}
1310
1311		/* Something happened, fail everything and bail. */
1312		if (BTRFS_FS_ERROR(fs_info))
1313			goto aborted_fs;
1314		last_tickets_id = space_info->tickets_id;
1315		spin_unlock(&space_info->lock);
1316	}
1317
1318	while (flush_state < ARRAY_SIZE(data_flush_states)) {
1319		flush_space(fs_info, space_info, U64_MAX,
1320			    data_flush_states[flush_state], false);
1321		spin_lock(&space_info->lock);
1322		if (list_empty(&space_info->tickets)) {
1323			space_info->flush = 0;
1324			spin_unlock(&space_info->lock);
1325			return;
1326		}
1327
1328		if (last_tickets_id == space_info->tickets_id) {
1329			flush_state++;
1330		} else {
1331			last_tickets_id = space_info->tickets_id;
1332			flush_state = 0;
1333		}
1334
1335		if (flush_state >= ARRAY_SIZE(data_flush_states)) {
1336			if (space_info->full) {
1337				if (maybe_fail_all_tickets(fs_info, space_info))
1338					flush_state = 0;
1339				else
1340					space_info->flush = 0;
1341			} else {
1342				flush_state = 0;
1343			}
1344
1345			/* Something happened, fail everything and bail. */
1346			if (BTRFS_FS_ERROR(fs_info))
1347				goto aborted_fs;
1348
1349		}
1350		spin_unlock(&space_info->lock);
1351	}
1352	return;
1353
1354aborted_fs:
1355	maybe_fail_all_tickets(fs_info, space_info);
1356	space_info->flush = 0;
1357	spin_unlock(&space_info->lock);
1358}
1359
1360void btrfs_init_async_reclaim_work(struct btrfs_fs_info *fs_info)
1361{
1362	INIT_WORK(&fs_info->async_reclaim_work, btrfs_async_reclaim_metadata_space);
1363	INIT_WORK(&fs_info->async_data_reclaim_work, btrfs_async_reclaim_data_space);
1364	INIT_WORK(&fs_info->preempt_reclaim_work,
1365		  btrfs_preempt_reclaim_metadata_space);
1366}
1367
1368static const enum btrfs_flush_state priority_flush_states[] = {
1369	FLUSH_DELAYED_ITEMS_NR,
1370	FLUSH_DELAYED_ITEMS,
1371	ALLOC_CHUNK,
1372};
1373
1374static const enum btrfs_flush_state evict_flush_states[] = {
1375	FLUSH_DELAYED_ITEMS_NR,
1376	FLUSH_DELAYED_ITEMS,
1377	FLUSH_DELAYED_REFS_NR,
1378	FLUSH_DELAYED_REFS,
1379	FLUSH_DELALLOC,
1380	FLUSH_DELALLOC_WAIT,
1381	FLUSH_DELALLOC_FULL,
1382	ALLOC_CHUNK,
1383	COMMIT_TRANS,
1384};
1385
1386static void priority_reclaim_metadata_space(struct btrfs_fs_info *fs_info,
1387				struct btrfs_space_info *space_info,
1388				struct reserve_ticket *ticket,
1389				const enum btrfs_flush_state *states,
1390				int states_nr)
1391{
1392	u64 to_reclaim;
1393	int flush_state = 0;
1394
1395	spin_lock(&space_info->lock);
1396	to_reclaim = btrfs_calc_reclaim_metadata_size(fs_info, space_info);
1397	/*
1398	 * This is the priority reclaim path, so to_reclaim could be >0 still
1399	 * because we may have only satisfied the priority tickets and still
1400	 * left non priority tickets on the list.  We would then have
1401	 * to_reclaim but ->bytes == 0.
1402	 */
1403	if (ticket->bytes == 0) {
1404		spin_unlock(&space_info->lock);
1405		return;
1406	}
1407
1408	while (flush_state < states_nr) {
1409		spin_unlock(&space_info->lock);
1410		flush_space(fs_info, space_info, to_reclaim, states[flush_state],
1411			    false);
1412		flush_state++;
1413		spin_lock(&space_info->lock);
1414		if (ticket->bytes == 0) {
1415			spin_unlock(&space_info->lock);
1416			return;
1417		}
1418	}
1419
1420	/* Attempt to steal from the global rsv if we can. */
1421	if (!steal_from_global_rsv(fs_info, space_info, ticket)) {
 
 
 
 
 
 
 
 
 
 
1422		ticket->error = -ENOSPC;
1423		remove_ticket(space_info, ticket);
1424	}
1425
1426	/*
1427	 * We must run try_granting_tickets here because we could be a large
1428	 * ticket in front of a smaller ticket that can now be satisfied with
1429	 * the available space.
1430	 */
1431	btrfs_try_granting_tickets(fs_info, space_info);
1432	spin_unlock(&space_info->lock);
1433}
1434
1435static void priority_reclaim_data_space(struct btrfs_fs_info *fs_info,
1436					struct btrfs_space_info *space_info,
1437					struct reserve_ticket *ticket)
1438{
1439	spin_lock(&space_info->lock);
1440
1441	/* We could have been granted before we got here. */
1442	if (ticket->bytes == 0) {
1443		spin_unlock(&space_info->lock);
1444		return;
1445	}
1446
1447	while (!space_info->full) {
1448		spin_unlock(&space_info->lock);
1449		flush_space(fs_info, space_info, U64_MAX, ALLOC_CHUNK_FORCE, false);
1450		spin_lock(&space_info->lock);
1451		if (ticket->bytes == 0) {
1452			spin_unlock(&space_info->lock);
1453			return;
1454		}
1455	}
1456
1457	ticket->error = -ENOSPC;
1458	remove_ticket(space_info, ticket);
1459	btrfs_try_granting_tickets(fs_info, space_info);
1460	spin_unlock(&space_info->lock);
1461}
1462
1463static void wait_reserve_ticket(struct btrfs_fs_info *fs_info,
1464				struct btrfs_space_info *space_info,
1465				struct reserve_ticket *ticket)
1466
1467{
1468	DEFINE_WAIT(wait);
1469	int ret = 0;
1470
1471	spin_lock(&space_info->lock);
1472	while (ticket->bytes > 0 && ticket->error == 0) {
1473		ret = prepare_to_wait_event(&ticket->wait, &wait, TASK_KILLABLE);
1474		if (ret) {
1475			/*
1476			 * Delete us from the list. After we unlock the space
1477			 * info, we don't want the async reclaim job to reserve
1478			 * space for this ticket. If that would happen, then the
1479			 * ticket's task would not known that space was reserved
1480			 * despite getting an error, resulting in a space leak
1481			 * (bytes_may_use counter of our space_info).
1482			 */
1483			remove_ticket(space_info, ticket);
1484			ticket->error = -EINTR;
1485			break;
1486		}
1487		spin_unlock(&space_info->lock);
1488
1489		schedule();
1490
1491		finish_wait(&ticket->wait, &wait);
1492		spin_lock(&space_info->lock);
1493	}
1494	spin_unlock(&space_info->lock);
1495}
1496
1497/*
1498 * Do the appropriate flushing and waiting for a ticket.
1499 *
1500 * @fs_info:    the filesystem
1501 * @space_info: space info for the reservation
1502 * @ticket:     ticket for the reservation
1503 * @start_ns:   timestamp when the reservation started
1504 * @orig_bytes: amount of bytes originally reserved
1505 * @flush:      how much we can flush
1506 *
1507 * This does the work of figuring out how to flush for the ticket, waiting for
1508 * the reservation, and returning the appropriate error if there is one.
1509 */
1510static int handle_reserve_ticket(struct btrfs_fs_info *fs_info,
1511				 struct btrfs_space_info *space_info,
1512				 struct reserve_ticket *ticket,
1513				 u64 start_ns, u64 orig_bytes,
1514				 enum btrfs_reserve_flush_enum flush)
1515{
1516	int ret;
1517
1518	switch (flush) {
1519	case BTRFS_RESERVE_FLUSH_DATA:
1520	case BTRFS_RESERVE_FLUSH_ALL:
1521	case BTRFS_RESERVE_FLUSH_ALL_STEAL:
1522		wait_reserve_ticket(fs_info, space_info, ticket);
1523		break;
1524	case BTRFS_RESERVE_FLUSH_LIMIT:
1525		priority_reclaim_metadata_space(fs_info, space_info, ticket,
1526						priority_flush_states,
1527						ARRAY_SIZE(priority_flush_states));
1528		break;
1529	case BTRFS_RESERVE_FLUSH_EVICT:
1530		priority_reclaim_metadata_space(fs_info, space_info, ticket,
1531						evict_flush_states,
1532						ARRAY_SIZE(evict_flush_states));
1533		break;
1534	case BTRFS_RESERVE_FLUSH_FREE_SPACE_INODE:
1535		priority_reclaim_data_space(fs_info, space_info, ticket);
1536		break;
1537	default:
1538		ASSERT(0);
1539		break;
1540	}
1541
1542	ret = ticket->error;
1543	ASSERT(list_empty(&ticket->list));
1544	/*
1545	 * Check that we can't have an error set if the reservation succeeded,
1546	 * as that would confuse tasks and lead them to error out without
1547	 * releasing reserved space (if an error happens the expectation is that
1548	 * space wasn't reserved at all).
1549	 */
1550	ASSERT(!(ticket->bytes == 0 && ticket->error));
1551	trace_btrfs_reserve_ticket(fs_info, space_info->flags, orig_bytes,
1552				   start_ns, flush, ticket->error);
1553	return ret;
1554}
1555
1556/*
1557 * This returns true if this flush state will go through the ordinary flushing
1558 * code.
1559 */
1560static inline bool is_normal_flushing(enum btrfs_reserve_flush_enum flush)
1561{
1562	return	(flush == BTRFS_RESERVE_FLUSH_ALL) ||
1563		(flush == BTRFS_RESERVE_FLUSH_ALL_STEAL);
1564}
1565
1566static inline void maybe_clamp_preempt(struct btrfs_fs_info *fs_info,
1567				       struct btrfs_space_info *space_info)
1568{
1569	u64 ordered = percpu_counter_sum_positive(&fs_info->ordered_bytes);
1570	u64 delalloc = percpu_counter_sum_positive(&fs_info->delalloc_bytes);
1571
1572	/*
1573	 * If we're heavy on ordered operations then clamping won't help us.  We
1574	 * need to clamp specifically to keep up with dirty'ing buffered
1575	 * writers, because there's not a 1:1 correlation of writing delalloc
1576	 * and freeing space, like there is with flushing delayed refs or
1577	 * delayed nodes.  If we're already more ordered than delalloc then
1578	 * we're keeping up, otherwise we aren't and should probably clamp.
1579	 */
1580	if (ordered < delalloc)
1581		space_info->clamp = min(space_info->clamp + 1, 8);
1582}
1583
1584static inline bool can_steal(enum btrfs_reserve_flush_enum flush)
1585{
1586	return (flush == BTRFS_RESERVE_FLUSH_ALL_STEAL ||
1587		flush == BTRFS_RESERVE_FLUSH_EVICT);
1588}
1589
1590/*
1591 * NO_FLUSH and FLUSH_EMERGENCY don't want to create a ticket, they just want to
1592 * fail as quickly as possible.
1593 */
1594static inline bool can_ticket(enum btrfs_reserve_flush_enum flush)
1595{
1596	return (flush != BTRFS_RESERVE_NO_FLUSH &&
1597		flush != BTRFS_RESERVE_FLUSH_EMERGENCY);
1598}
1599
1600/*
1601 * Try to reserve bytes from the block_rsv's space.
1602 *
1603 * @fs_info:    the filesystem
1604 * @space_info: space info we want to allocate from
1605 * @orig_bytes: number of bytes we want
1606 * @flush:      whether or not we can flush to make our reservation
1607 *
1608 * This will reserve orig_bytes number of bytes from the space info associated
1609 * with the block_rsv.  If there is not enough space it will make an attempt to
1610 * flush out space to make room.  It will do this by flushing delalloc if
1611 * possible or committing the transaction.  If flush is 0 then no attempts to
1612 * regain reservations will be made and this will fail if there is not enough
1613 * space already.
1614 */
1615static int __reserve_bytes(struct btrfs_fs_info *fs_info,
1616			   struct btrfs_space_info *space_info, u64 orig_bytes,
1617			   enum btrfs_reserve_flush_enum flush)
1618{
1619	struct work_struct *async_work;
1620	struct reserve_ticket ticket;
1621	u64 start_ns = 0;
1622	u64 used;
1623	int ret = 0;
1624	bool pending_tickets;
1625
1626	ASSERT(orig_bytes);
1627	ASSERT(!current->journal_info || flush != BTRFS_RESERVE_FLUSH_ALL);
 
 
 
 
 
 
 
 
 
 
 
1628
1629	if (flush == BTRFS_RESERVE_FLUSH_DATA)
1630		async_work = &fs_info->async_data_reclaim_work;
1631	else
1632		async_work = &fs_info->async_reclaim_work;
1633
1634	spin_lock(&space_info->lock);
1635	ret = -ENOSPC;
1636	used = btrfs_space_info_used(space_info, true);
1637
1638	/*
1639	 * We don't want NO_FLUSH allocations to jump everybody, they can
1640	 * generally handle ENOSPC in a different way, so treat them the same as
1641	 * normal flushers when it comes to skipping pending tickets.
1642	 */
1643	if (is_normal_flushing(flush) || (flush == BTRFS_RESERVE_NO_FLUSH))
1644		pending_tickets = !list_empty(&space_info->tickets) ||
1645			!list_empty(&space_info->priority_tickets);
1646	else
1647		pending_tickets = !list_empty(&space_info->priority_tickets);
1648
1649	/*
1650	 * Carry on if we have enough space (short-circuit) OR call
1651	 * can_overcommit() to ensure we can overcommit to continue.
1652	 */
1653	if (!pending_tickets &&
1654	    ((used + orig_bytes <= writable_total_bytes(fs_info, space_info)) ||
1655	     btrfs_can_overcommit(fs_info, space_info, orig_bytes, flush))) {
1656		btrfs_space_info_update_bytes_may_use(fs_info, space_info,
1657						      orig_bytes);
1658		ret = 0;
1659	}
1660
1661	/*
1662	 * Things are dire, we need to make a reservation so we don't abort.  We
1663	 * will let this reservation go through as long as we have actual space
1664	 * left to allocate for the block.
1665	 */
1666	if (ret && unlikely(flush == BTRFS_RESERVE_FLUSH_EMERGENCY)) {
1667		used = btrfs_space_info_used(space_info, false);
1668		if (used + orig_bytes <=
1669		    writable_total_bytes(fs_info, space_info)) {
1670			btrfs_space_info_update_bytes_may_use(fs_info, space_info,
1671							      orig_bytes);
1672			ret = 0;
1673		}
1674	}
1675
1676	/*
1677	 * If we couldn't make a reservation then setup our reservation ticket
1678	 * and kick the async worker if it's not already running.
1679	 *
1680	 * If we are a priority flusher then we just need to add our ticket to
1681	 * the list and we will do our own flushing further down.
1682	 */
1683	if (ret && can_ticket(flush)) {
1684		ticket.bytes = orig_bytes;
1685		ticket.error = 0;
1686		space_info->reclaim_size += ticket.bytes;
1687		init_waitqueue_head(&ticket.wait);
1688		ticket.steal = can_steal(flush);
1689		if (trace_btrfs_reserve_ticket_enabled())
1690			start_ns = ktime_get_ns();
1691
1692		if (flush == BTRFS_RESERVE_FLUSH_ALL ||
1693		    flush == BTRFS_RESERVE_FLUSH_ALL_STEAL ||
1694		    flush == BTRFS_RESERVE_FLUSH_DATA) {
1695			list_add_tail(&ticket.list, &space_info->tickets);
1696			if (!space_info->flush) {
1697				/*
1698				 * We were forced to add a reserve ticket, so
1699				 * our preemptive flushing is unable to keep
1700				 * up.  Clamp down on the threshold for the
1701				 * preemptive flushing in order to keep up with
1702				 * the workload.
1703				 */
1704				maybe_clamp_preempt(fs_info, space_info);
1705
1706				space_info->flush = 1;
1707				trace_btrfs_trigger_flush(fs_info,
1708							  space_info->flags,
1709							  orig_bytes, flush,
1710							  "enospc");
1711				queue_work(system_unbound_wq, async_work);
1712			}
1713		} else {
1714			list_add_tail(&ticket.list,
1715				      &space_info->priority_tickets);
1716		}
1717	} else if (!ret && space_info->flags & BTRFS_BLOCK_GROUP_METADATA) {
1718		/*
1719		 * We will do the space reservation dance during log replay,
1720		 * which means we won't have fs_info->fs_root set, so don't do
1721		 * the async reclaim as we will panic.
1722		 */
1723		if (!test_bit(BTRFS_FS_LOG_RECOVERING, &fs_info->flags) &&
1724		    !work_busy(&fs_info->preempt_reclaim_work) &&
1725		    need_preemptive_reclaim(fs_info, space_info)) {
1726			trace_btrfs_trigger_flush(fs_info, space_info->flags,
1727						  orig_bytes, flush, "preempt");
1728			queue_work(system_unbound_wq,
1729				   &fs_info->preempt_reclaim_work);
1730		}
1731	}
1732	spin_unlock(&space_info->lock);
1733	if (!ret || !can_ticket(flush))
1734		return ret;
1735
1736	return handle_reserve_ticket(fs_info, space_info, &ticket, start_ns,
1737				     orig_bytes, flush);
1738}
1739
1740/*
1741 * Try to reserve metadata bytes from the block_rsv's space.
1742 *
1743 * @fs_info:    the filesystem
1744 * @block_rsv:  block_rsv we're allocating for
1745 * @orig_bytes: number of bytes we want
1746 * @flush:      whether or not we can flush to make our reservation
1747 *
1748 * This will reserve orig_bytes number of bytes from the space info associated
1749 * with the block_rsv.  If there is not enough space it will make an attempt to
1750 * flush out space to make room.  It will do this by flushing delalloc if
1751 * possible or committing the transaction.  If flush is 0 then no attempts to
1752 * regain reservations will be made and this will fail if there is not enough
1753 * space already.
1754 */
1755int btrfs_reserve_metadata_bytes(struct btrfs_fs_info *fs_info,
1756				 struct btrfs_block_rsv *block_rsv,
1757				 u64 orig_bytes,
1758				 enum btrfs_reserve_flush_enum flush)
1759{
1760	int ret;
1761
1762	ret = __reserve_bytes(fs_info, block_rsv->space_info, orig_bytes, flush);
1763	if (ret == -ENOSPC) {
1764		trace_btrfs_space_reservation(fs_info, "space_info:enospc",
1765					      block_rsv->space_info->flags,
1766					      orig_bytes, 1);
1767
1768		if (btrfs_test_opt(fs_info, ENOSPC_DEBUG))
1769			btrfs_dump_space_info(fs_info, block_rsv->space_info,
1770					      orig_bytes, 0);
1771	}
1772	return ret;
1773}
1774
1775/*
1776 * Try to reserve data bytes for an allocation.
1777 *
1778 * @fs_info: the filesystem
1779 * @bytes:   number of bytes we need
1780 * @flush:   how we are allowed to flush
1781 *
1782 * This will reserve bytes from the data space info.  If there is not enough
1783 * space then we will attempt to flush space as specified by flush.
1784 */
1785int btrfs_reserve_data_bytes(struct btrfs_fs_info *fs_info, u64 bytes,
1786			     enum btrfs_reserve_flush_enum flush)
1787{
1788	struct btrfs_space_info *data_sinfo = fs_info->data_sinfo;
1789	int ret;
1790
1791	ASSERT(flush == BTRFS_RESERVE_FLUSH_DATA ||
1792	       flush == BTRFS_RESERVE_FLUSH_FREE_SPACE_INODE ||
1793	       flush == BTRFS_RESERVE_NO_FLUSH);
1794	ASSERT(!current->journal_info || flush != BTRFS_RESERVE_FLUSH_DATA);
1795
1796	ret = __reserve_bytes(fs_info, data_sinfo, bytes, flush);
1797	if (ret == -ENOSPC) {
1798		trace_btrfs_space_reservation(fs_info, "space_info:enospc",
1799					      data_sinfo->flags, bytes, 1);
1800		if (btrfs_test_opt(fs_info, ENOSPC_DEBUG))
1801			btrfs_dump_space_info(fs_info, data_sinfo, bytes, 0);
1802	}
1803	return ret;
1804}
1805
1806/* Dump all the space infos when we abort a transaction due to ENOSPC. */
1807__cold void btrfs_dump_space_info_for_trans_abort(struct btrfs_fs_info *fs_info)
1808{
1809	struct btrfs_space_info *space_info;
1810
1811	btrfs_info(fs_info, "dumping space info:");
1812	list_for_each_entry(space_info, &fs_info->space_info, list) {
1813		spin_lock(&space_info->lock);
1814		__btrfs_dump_space_info(fs_info, space_info);
1815		spin_unlock(&space_info->lock);
1816	}
1817	dump_global_block_rsv(fs_info);
1818}
1819
1820/*
1821 * Account the unused space of all the readonly block group in the space_info.
1822 * takes mirrors into account.
1823 */
1824u64 btrfs_account_ro_block_groups_free_space(struct btrfs_space_info *sinfo)
1825{
1826	struct btrfs_block_group *block_group;
1827	u64 free_bytes = 0;
1828	int factor;
1829
1830	/* It's df, we don't care if it's racy */
1831	if (list_empty(&sinfo->ro_bgs))
1832		return 0;
1833
1834	spin_lock(&sinfo->lock);
1835	list_for_each_entry(block_group, &sinfo->ro_bgs, ro_list) {
1836		spin_lock(&block_group->lock);
1837
1838		if (!block_group->ro) {
1839			spin_unlock(&block_group->lock);
1840			continue;
1841		}
1842
1843		factor = btrfs_bg_type_to_factor(block_group->flags);
1844		free_bytes += (block_group->length -
1845			       block_group->used) * factor;
1846
1847		spin_unlock(&block_group->lock);
1848	}
1849	spin_unlock(&sinfo->lock);
1850
1851	return free_bytes;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1852}