1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * Copyright (C) 2007 Oracle.  All rights reserved.
   4 */
   5
   6#include <linux/sched.h>
   7#include <linux/sched/signal.h>
   8#include <linux/pagemap.h>
   9#include <linux/writeback.h>
  10#include <linux/blkdev.h>
  11#include <linux/sort.h>
  12#include <linux/rcupdate.h>
  13#include <linux/kthread.h>
  14#include <linux/slab.h>
  15#include <linux/ratelimit.h>
  16#include <linux/percpu_counter.h>
  17#include <linux/lockdep.h>
  18#include <linux/crc32c.h>
  19#include "misc.h"
  20#include "tree-log.h"
  21#include "disk-io.h"
  22#include "print-tree.h"
  23#include "volumes.h"
  24#include "raid56.h"
  25#include "locking.h"
  26#include "free-space-cache.h"
  27#include "free-space-tree.h"
  28#include "sysfs.h"
  29#include "qgroup.h"
  30#include "ref-verify.h"
  31#include "space-info.h"
  32#include "block-rsv.h"
  33#include "delalloc-space.h"
  34#include "block-group.h"
 
 
 
 
 
 
 
 
 
 
 
  35
  36#undef SCRAMBLE_DELAYED_REFS
  37
  38
  39static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
  40			       struct btrfs_delayed_ref_node *node, u64 parent,
  41			       u64 root_objectid, u64 owner_objectid,
  42			       u64 owner_offset, int refs_to_drop,
  43			       struct btrfs_delayed_extent_op *extra_op);
  44static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
  45				    struct extent_buffer *leaf,
  46				    struct btrfs_extent_item *ei);
  47static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
  48				      u64 parent, u64 root_objectid,
  49				      u64 flags, u64 owner, u64 offset,
  50				      struct btrfs_key *ins, int ref_mod);
  51static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
  52				     struct btrfs_delayed_ref_node *node,
  53				     struct btrfs_delayed_extent_op *extent_op);
  54static int find_next_key(struct btrfs_path *path, int level,
  55			 struct btrfs_key *key);
  56
  57static int block_group_bits(struct btrfs_block_group_cache *cache, u64 bits)
  58{
  59	return (cache->flags & bits) == bits;
  60}
  61
  62int btrfs_add_excluded_extent(struct btrfs_fs_info *fs_info,
  63			      u64 start, u64 num_bytes)
  64{
  65	u64 end = start + num_bytes - 1;
  66	set_extent_bits(&fs_info->freed_extents[0],
  67			start, end, EXTENT_UPTODATE);
  68	set_extent_bits(&fs_info->freed_extents[1],
  69			start, end, EXTENT_UPTODATE);
  70	return 0;
  71}
  72
  73void btrfs_free_excluded_extents(struct btrfs_block_group_cache *cache)
  74{
  75	struct btrfs_fs_info *fs_info = cache->fs_info;
  76	u64 start, end;
  77
  78	start = cache->key.objectid;
  79	end = start + cache->key.offset - 1;
  80
  81	clear_extent_bits(&fs_info->freed_extents[0],
  82			  start, end, EXTENT_UPTODATE);
  83	clear_extent_bits(&fs_info->freed_extents[1],
  84			  start, end, EXTENT_UPTODATE);
  85}
  86
  87static u64 generic_ref_to_space_flags(struct btrfs_ref *ref)
  88{
  89	if (ref->type == BTRFS_REF_METADATA) {
  90		if (ref->tree_ref.root == BTRFS_CHUNK_TREE_OBJECTID)
  91			return BTRFS_BLOCK_GROUP_SYSTEM;
  92		else
  93			return BTRFS_BLOCK_GROUP_METADATA;
  94	}
  95	return BTRFS_BLOCK_GROUP_DATA;
  96}
  97
  98static void add_pinned_bytes(struct btrfs_fs_info *fs_info,
  99			     struct btrfs_ref *ref)
 100{
 101	struct btrfs_space_info *space_info;
 102	u64 flags = generic_ref_to_space_flags(ref);
 103
 104	space_info = btrfs_find_space_info(fs_info, flags);
 105	ASSERT(space_info);
 106	percpu_counter_add_batch(&space_info->total_bytes_pinned, ref->len,
 107		    BTRFS_TOTAL_BYTES_PINNED_BATCH);
 108}
 109
 110static void sub_pinned_bytes(struct btrfs_fs_info *fs_info,
 111			     struct btrfs_ref *ref)
 112{
 113	struct btrfs_space_info *space_info;
 114	u64 flags = generic_ref_to_space_flags(ref);
 115
 116	space_info = btrfs_find_space_info(fs_info, flags);
 117	ASSERT(space_info);
 118	percpu_counter_add_batch(&space_info->total_bytes_pinned, -ref->len,
 119		    BTRFS_TOTAL_BYTES_PINNED_BATCH);
 120}
 121
 122/* simple helper to search for an existing data extent at a given offset */
 123int btrfs_lookup_data_extent(struct btrfs_fs_info *fs_info, u64 start, u64 len)
 124{
 
 125	int ret;
 126	struct btrfs_key key;
 127	struct btrfs_path *path;
 128
 129	path = btrfs_alloc_path();
 130	if (!path)
 131		return -ENOMEM;
 132
 133	key.objectid = start;
 134	key.offset = len;
 135	key.type = BTRFS_EXTENT_ITEM_KEY;
 136	ret = btrfs_search_slot(NULL, fs_info->extent_root, &key, path, 0, 0);
 137	btrfs_free_path(path);
 138	return ret;
 139}
 140
 141/*
 142 * helper function to lookup reference count and flags of a tree block.
 143 *
 144 * the head node for delayed ref is used to store the sum of all the
 145 * reference count modifications queued up in the rbtree. the head
 146 * node may also store the extent flags to set. This way you can check
 147 * to see what the reference count and extent flags would be if all of
 148 * the delayed refs are not processed.
 149 */
 150int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans,
 151			     struct btrfs_fs_info *fs_info, u64 bytenr,
 152			     u64 offset, int metadata, u64 *refs, u64 *flags)
 153{
 
 154	struct btrfs_delayed_ref_head *head;
 155	struct btrfs_delayed_ref_root *delayed_refs;
 156	struct btrfs_path *path;
 157	struct btrfs_extent_item *ei;
 158	struct extent_buffer *leaf;
 159	struct btrfs_key key;
 160	u32 item_size;
 161	u64 num_refs;
 162	u64 extent_flags;
 163	int ret;
 164
 165	/*
 166	 * If we don't have skinny metadata, don't bother doing anything
 167	 * different
 168	 */
 169	if (metadata && !btrfs_fs_incompat(fs_info, SKINNY_METADATA)) {
 170		offset = fs_info->nodesize;
 171		metadata = 0;
 172	}
 173
 174	path = btrfs_alloc_path();
 175	if (!path)
 176		return -ENOMEM;
 177
 178	if (!trans) {
 179		path->skip_locking = 1;
 180		path->search_commit_root = 1;
 181	}
 182
 183search_again:
 184	key.objectid = bytenr;
 185	key.offset = offset;
 186	if (metadata)
 187		key.type = BTRFS_METADATA_ITEM_KEY;
 188	else
 189		key.type = BTRFS_EXTENT_ITEM_KEY;
 190
 191	ret = btrfs_search_slot(trans, fs_info->extent_root, &key, path, 0, 0);
 
 192	if (ret < 0)
 193		goto out_free;
 194
 195	if (ret > 0 && metadata && key.type == BTRFS_METADATA_ITEM_KEY) {
 196		if (path->slots[0]) {
 197			path->slots[0]--;
 198			btrfs_item_key_to_cpu(path->nodes[0], &key,
 199					      path->slots[0]);
 200			if (key.objectid == bytenr &&
 201			    key.type == BTRFS_EXTENT_ITEM_KEY &&
 202			    key.offset == fs_info->nodesize)
 203				ret = 0;
 204		}
 205	}
 206
 207	if (ret == 0) {
 208		leaf = path->nodes[0];
 209		item_size = btrfs_item_size_nr(leaf, path->slots[0]);
 210		if (item_size >= sizeof(*ei)) {
 211			ei = btrfs_item_ptr(leaf, path->slots[0],
 212					    struct btrfs_extent_item);
 213			num_refs = btrfs_extent_refs(leaf, ei);
 214			extent_flags = btrfs_extent_flags(leaf, ei);
 215		} else {
 216			ret = -EINVAL;
 217			btrfs_print_v0_err(fs_info);
 218			if (trans)
 219				btrfs_abort_transaction(trans, ret);
 220			else
 221				btrfs_handle_fs_error(fs_info, ret, NULL);
 222
 223			goto out_free;
 224		}
 225
 226		BUG_ON(num_refs == 0);
 227	} else {
 228		num_refs = 0;
 229		extent_flags = 0;
 230		ret = 0;
 231	}
 232
 233	if (!trans)
 234		goto out;
 235
 236	delayed_refs = &trans->transaction->delayed_refs;
 237	spin_lock(&delayed_refs->lock);
 238	head = btrfs_find_delayed_ref_head(delayed_refs, bytenr);
 239	if (head) {
 240		if (!mutex_trylock(&head->mutex)) {
 241			refcount_inc(&head->refs);
 242			spin_unlock(&delayed_refs->lock);
 243
 244			btrfs_release_path(path);
 245
 246			/*
 247			 * Mutex was contended, block until it's released and try
 248			 * again
 249			 */
 250			mutex_lock(&head->mutex);
 251			mutex_unlock(&head->mutex);
 252			btrfs_put_delayed_ref_head(head);
 253			goto search_again;
 254		}
 255		spin_lock(&head->lock);
 256		if (head->extent_op && head->extent_op->update_flags)
 257			extent_flags |= head->extent_op->flags_to_set;
 258		else
 259			BUG_ON(num_refs == 0);
 260
 261		num_refs += head->ref_mod;
 262		spin_unlock(&head->lock);
 263		mutex_unlock(&head->mutex);
 264	}
 265	spin_unlock(&delayed_refs->lock);
 266out:
 267	WARN_ON(num_refs == 0);
 268	if (refs)
 269		*refs = num_refs;
 270	if (flags)
 271		*flags = extent_flags;
 272out_free:
 273	btrfs_free_path(path);
 274	return ret;
 275}
 276
 277/*
 278 * Back reference rules.  Back refs have three main goals:
 279 *
 280 * 1) differentiate between all holders of references to an extent so that
 281 *    when a reference is dropped we can make sure it was a valid reference
 282 *    before freeing the extent.
 283 *
 284 * 2) Provide enough information to quickly find the holders of an extent
 285 *    if we notice a given block is corrupted or bad.
 286 *
 287 * 3) Make it easy to migrate blocks for FS shrinking or storage pool
 288 *    maintenance.  This is actually the same as #2, but with a slightly
 289 *    different use case.
 290 *
 291 * There are two kinds of back refs. The implicit back refs is optimized
 292 * for pointers in non-shared tree blocks. For a given pointer in a block,
 293 * back refs of this kind provide information about the block's owner tree
 294 * and the pointer's key. These information allow us to find the block by
 295 * b-tree searching. The full back refs is for pointers in tree blocks not
 296 * referenced by their owner trees. The location of tree block is recorded
 297 * in the back refs. Actually the full back refs is generic, and can be
 298 * used in all cases the implicit back refs is used. The major shortcoming
 299 * of the full back refs is its overhead. Every time a tree block gets
 300 * COWed, we have to update back refs entry for all pointers in it.
 301 *
 302 * For a newly allocated tree block, we use implicit back refs for
 303 * pointers in it. This means most tree related operations only involve
 304 * implicit back refs. For a tree block created in old transaction, the
 305 * only way to drop a reference to it is COW it. So we can detect the
 306 * event that tree block loses its owner tree's reference and do the
 307 * back refs conversion.
 308 *
 309 * When a tree block is COWed through a tree, there are four cases:
 310 *
 311 * The reference count of the block is one and the tree is the block's
 312 * owner tree. Nothing to do in this case.
 313 *
 314 * The reference count of the block is one and the tree is not the
 315 * block's owner tree. In this case, full back refs is used for pointers
 316 * in the block. Remove these full back refs, add implicit back refs for
 317 * every pointers in the new block.
 318 *
 319 * The reference count of the block is greater than one and the tree is
 320 * the block's owner tree. In this case, implicit back refs is used for
 321 * pointers in the block. Add full back refs for every pointers in the
 322 * block, increase lower level extents' reference counts. The original
 323 * implicit back refs are entailed to the new block.
 324 *
 325 * The reference count of the block is greater than one and the tree is
 326 * not the block's owner tree. Add implicit back refs for every pointer in
 327 * the new block, increase lower level extents' reference count.
 328 *
 329 * Back Reference Key composing:
 330 *
 331 * The key objectid corresponds to the first byte in the extent,
 332 * The key type is used to differentiate between types of back refs.
 333 * There are different meanings of the key offset for different types
 334 * of back refs.
 335 *
 336 * File extents can be referenced by:
 337 *
 338 * - multiple snapshots, subvolumes, or different generations in one subvol
 339 * - different files inside a single subvolume
 340 * - different offsets inside a file (bookend extents in file.c)
 341 *
 342 * The extent ref structure for the implicit back refs has fields for:
 343 *
 344 * - Objectid of the subvolume root
 345 * - objectid of the file holding the reference
 346 * - original offset in the file
 347 * - how many bookend extents
 348 *
 349 * The key offset for the implicit back refs is hash of the first
 350 * three fields.
 351 *
 352 * The extent ref structure for the full back refs has field for:
 353 *
 354 * - number of pointers in the tree leaf
 355 *
 356 * The key offset for the implicit back refs is the first byte of
 357 * the tree leaf
 358 *
 359 * When a file extent is allocated, The implicit back refs is used.
 360 * the fields are filled in:
 361 *
 362 *     (root_key.objectid, inode objectid, offset in file, 1)
 363 *
 364 * When a file extent is removed file truncation, we find the
 365 * corresponding implicit back refs and check the following fields:
 366 *
 367 *     (btrfs_header_owner(leaf), inode objectid, offset in file)
 368 *
 369 * Btree extents can be referenced by:
 370 *
 371 * - Different subvolumes
 372 *
 373 * Both the implicit back refs and the full back refs for tree blocks
 374 * only consist of key. The key offset for the implicit back refs is
 375 * objectid of block's owner tree. The key offset for the full back refs
 376 * is the first byte of parent block.
 377 *
 378 * When implicit back refs is used, information about the lowest key and
 379 * level of the tree block are required. These information are stored in
 380 * tree block info structure.
 381 */
 382
 383/*
 384 * is_data == BTRFS_REF_TYPE_BLOCK, tree block type is required,
 385 * is_data == BTRFS_REF_TYPE_DATA, data type is requiried,
 386 * is_data == BTRFS_REF_TYPE_ANY, either type is OK.
 387 */
 388int btrfs_get_extent_inline_ref_type(const struct extent_buffer *eb,
 389				     struct btrfs_extent_inline_ref *iref,
 390				     enum btrfs_inline_ref_type is_data)
 391{
 392	int type = btrfs_extent_inline_ref_type(eb, iref);
 393	u64 offset = btrfs_extent_inline_ref_offset(eb, iref);
 394
 395	if (type == BTRFS_TREE_BLOCK_REF_KEY ||
 396	    type == BTRFS_SHARED_BLOCK_REF_KEY ||
 397	    type == BTRFS_SHARED_DATA_REF_KEY ||
 398	    type == BTRFS_EXTENT_DATA_REF_KEY) {
 399		if (is_data == BTRFS_REF_TYPE_BLOCK) {
 400			if (type == BTRFS_TREE_BLOCK_REF_KEY)
 401				return type;
 402			if (type == BTRFS_SHARED_BLOCK_REF_KEY) {
 403				ASSERT(eb->fs_info);
 404				/*
 405				 * Every shared one has parent tree
 406				 * block, which must be aligned to
 407				 * nodesize.
 408				 */
 409				if (offset &&
 410				    IS_ALIGNED(offset, eb->fs_info->nodesize))
 411					return type;
 412			}
 413		} else if (is_data == BTRFS_REF_TYPE_DATA) {
 414			if (type == BTRFS_EXTENT_DATA_REF_KEY)
 415				return type;
 416			if (type == BTRFS_SHARED_DATA_REF_KEY) {
 417				ASSERT(eb->fs_info);
 418				/*
 419				 * Every shared one has parent tree
 420				 * block, which must be aligned to
 421				 * nodesize.
 422				 */
 423				if (offset &&
 424				    IS_ALIGNED(offset, eb->fs_info->nodesize))
 425					return type;
 426			}
 427		} else {
 428			ASSERT(is_data == BTRFS_REF_TYPE_ANY);
 429			return type;
 430		}
 431	}
 432
 433	btrfs_print_leaf((struct extent_buffer *)eb);
 434	btrfs_err(eb->fs_info, "eb %llu invalid extent inline ref type %d",
 435		  eb->start, type);
 
 436	WARN_ON(1);
 437
 438	return BTRFS_REF_TYPE_INVALID;
 439}
 440
 441u64 hash_extent_data_ref(u64 root_objectid, u64 owner, u64 offset)
 442{
 443	u32 high_crc = ~(u32)0;
 444	u32 low_crc = ~(u32)0;
 445	__le64 lenum;
 446
 447	lenum = cpu_to_le64(root_objectid);
 448	high_crc = btrfs_crc32c(high_crc, &lenum, sizeof(lenum));
 449	lenum = cpu_to_le64(owner);
 450	low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum));
 451	lenum = cpu_to_le64(offset);
 452	low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum));
 453
 454	return ((u64)high_crc << 31) ^ (u64)low_crc;
 455}
 456
 457static u64 hash_extent_data_ref_item(struct extent_buffer *leaf,
 458				     struct btrfs_extent_data_ref *ref)
 459{
 460	return hash_extent_data_ref(btrfs_extent_data_ref_root(leaf, ref),
 461				    btrfs_extent_data_ref_objectid(leaf, ref),
 462				    btrfs_extent_data_ref_offset(leaf, ref));
 463}
 464
 465static int match_extent_data_ref(struct extent_buffer *leaf,
 466				 struct btrfs_extent_data_ref *ref,
 467				 u64 root_objectid, u64 owner, u64 offset)
 468{
 469	if (btrfs_extent_data_ref_root(leaf, ref) != root_objectid ||
 470	    btrfs_extent_data_ref_objectid(leaf, ref) != owner ||
 471	    btrfs_extent_data_ref_offset(leaf, ref) != offset)
 472		return 0;
 473	return 1;
 474}
 475
 476static noinline int lookup_extent_data_ref(struct btrfs_trans_handle *trans,
 477					   struct btrfs_path *path,
 478					   u64 bytenr, u64 parent,
 479					   u64 root_objectid,
 480					   u64 owner, u64 offset)
 481{
 482	struct btrfs_root *root = trans->fs_info->extent_root;
 483	struct btrfs_key key;
 484	struct btrfs_extent_data_ref *ref;
 485	struct extent_buffer *leaf;
 486	u32 nritems;
 487	int ret;
 488	int recow;
 489	int err = -ENOENT;
 490
 491	key.objectid = bytenr;
 492	if (parent) {
 493		key.type = BTRFS_SHARED_DATA_REF_KEY;
 494		key.offset = parent;
 495	} else {
 496		key.type = BTRFS_EXTENT_DATA_REF_KEY;
 497		key.offset = hash_extent_data_ref(root_objectid,
 498						  owner, offset);
 499	}
 500again:
 501	recow = 0;
 502	ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
 503	if (ret < 0) {
 504		err = ret;
 505		goto fail;
 506	}
 507
 508	if (parent) {
 509		if (!ret)
 510			return 0;
 511		goto fail;
 512	}
 513
 514	leaf = path->nodes[0];
 515	nritems = btrfs_header_nritems(leaf);
 516	while (1) {
 517		if (path->slots[0] >= nritems) {
 518			ret = btrfs_next_leaf(root, path);
 519			if (ret < 0)
 520				err = ret;
 521			if (ret)
 522				goto fail;
 523
 524			leaf = path->nodes[0];
 525			nritems = btrfs_header_nritems(leaf);
 526			recow = 1;
 527		}
 528
 529		btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 530		if (key.objectid != bytenr ||
 531		    key.type != BTRFS_EXTENT_DATA_REF_KEY)
 532			goto fail;
 533
 534		ref = btrfs_item_ptr(leaf, path->slots[0],
 535				     struct btrfs_extent_data_ref);
 536
 537		if (match_extent_data_ref(leaf, ref, root_objectid,
 538					  owner, offset)) {
 539			if (recow) {
 540				btrfs_release_path(path);
 541				goto again;
 542			}
 543			err = 0;
 544			break;
 545		}
 546		path->slots[0]++;
 547	}
 548fail:
 549	return err;
 550}
 551
 552static noinline int insert_extent_data_ref(struct btrfs_trans_handle *trans,
 553					   struct btrfs_path *path,
 554					   u64 bytenr, u64 parent,
 555					   u64 root_objectid, u64 owner,
 556					   u64 offset, int refs_to_add)
 557{
 558	struct btrfs_root *root = trans->fs_info->extent_root;
 559	struct btrfs_key key;
 560	struct extent_buffer *leaf;
 561	u32 size;
 562	u32 num_refs;
 563	int ret;
 564
 565	key.objectid = bytenr;
 566	if (parent) {
 567		key.type = BTRFS_SHARED_DATA_REF_KEY;
 568		key.offset = parent;
 569		size = sizeof(struct btrfs_shared_data_ref);
 570	} else {
 571		key.type = BTRFS_EXTENT_DATA_REF_KEY;
 572		key.offset = hash_extent_data_ref(root_objectid,
 573						  owner, offset);
 574		size = sizeof(struct btrfs_extent_data_ref);
 575	}
 576
 577	ret = btrfs_insert_empty_item(trans, root, path, &key, size);
 578	if (ret && ret != -EEXIST)
 579		goto fail;
 580
 581	leaf = path->nodes[0];
 582	if (parent) {
 583		struct btrfs_shared_data_ref *ref;
 584		ref = btrfs_item_ptr(leaf, path->slots[0],
 585				     struct btrfs_shared_data_ref);
 586		if (ret == 0) {
 587			btrfs_set_shared_data_ref_count(leaf, ref, refs_to_add);
 588		} else {
 589			num_refs = btrfs_shared_data_ref_count(leaf, ref);
 590			num_refs += refs_to_add;
 591			btrfs_set_shared_data_ref_count(leaf, ref, num_refs);
 592		}
 593	} else {
 594		struct btrfs_extent_data_ref *ref;
 595		while (ret == -EEXIST) {
 596			ref = btrfs_item_ptr(leaf, path->slots[0],
 597					     struct btrfs_extent_data_ref);
 598			if (match_extent_data_ref(leaf, ref, root_objectid,
 599						  owner, offset))
 600				break;
 601			btrfs_release_path(path);
 602			key.offset++;
 603			ret = btrfs_insert_empty_item(trans, root, path, &key,
 604						      size);
 605			if (ret && ret != -EEXIST)
 606				goto fail;
 607
 608			leaf = path->nodes[0];
 609		}
 610		ref = btrfs_item_ptr(leaf, path->slots[0],
 611				     struct btrfs_extent_data_ref);
 612		if (ret == 0) {
 613			btrfs_set_extent_data_ref_root(leaf, ref,
 614						       root_objectid);
 615			btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
 616			btrfs_set_extent_data_ref_offset(leaf, ref, offset);
 617			btrfs_set_extent_data_ref_count(leaf, ref, refs_to_add);
 618		} else {
 619			num_refs = btrfs_extent_data_ref_count(leaf, ref);
 620			num_refs += refs_to_add;
 621			btrfs_set_extent_data_ref_count(leaf, ref, num_refs);
 622		}
 623	}
 624	btrfs_mark_buffer_dirty(leaf);
 625	ret = 0;
 626fail:
 627	btrfs_release_path(path);
 628	return ret;
 629}
 630
 631static noinline int remove_extent_data_ref(struct btrfs_trans_handle *trans,
 
 632					   struct btrfs_path *path,
 633					   int refs_to_drop, int *last_ref)
 634{
 635	struct btrfs_key key;
 636	struct btrfs_extent_data_ref *ref1 = NULL;
 637	struct btrfs_shared_data_ref *ref2 = NULL;
 638	struct extent_buffer *leaf;
 639	u32 num_refs = 0;
 640	int ret = 0;
 641
 642	leaf = path->nodes[0];
 643	btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 644
 645	if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
 646		ref1 = btrfs_item_ptr(leaf, path->slots[0],
 647				      struct btrfs_extent_data_ref);
 648		num_refs = btrfs_extent_data_ref_count(leaf, ref1);
 649	} else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
 650		ref2 = btrfs_item_ptr(leaf, path->slots[0],
 651				      struct btrfs_shared_data_ref);
 652		num_refs = btrfs_shared_data_ref_count(leaf, ref2);
 653	} else if (unlikely(key.type == BTRFS_EXTENT_REF_V0_KEY)) {
 654		btrfs_print_v0_err(trans->fs_info);
 655		btrfs_abort_transaction(trans, -EINVAL);
 656		return -EINVAL;
 657	} else {
 658		BUG();
 659	}
 660
 661	BUG_ON(num_refs < refs_to_drop);
 662	num_refs -= refs_to_drop;
 663
 664	if (num_refs == 0) {
 665		ret = btrfs_del_item(trans, trans->fs_info->extent_root, path);
 666		*last_ref = 1;
 667	} else {
 668		if (key.type == BTRFS_EXTENT_DATA_REF_KEY)
 669			btrfs_set_extent_data_ref_count(leaf, ref1, num_refs);
 670		else if (key.type == BTRFS_SHARED_DATA_REF_KEY)
 671			btrfs_set_shared_data_ref_count(leaf, ref2, num_refs);
 672		btrfs_mark_buffer_dirty(leaf);
 673	}
 674	return ret;
 675}
 676
 677static noinline u32 extent_data_ref_count(struct btrfs_path *path,
 678					  struct btrfs_extent_inline_ref *iref)
 679{
 680	struct btrfs_key key;
 681	struct extent_buffer *leaf;
 682	struct btrfs_extent_data_ref *ref1;
 683	struct btrfs_shared_data_ref *ref2;
 684	u32 num_refs = 0;
 685	int type;
 686
 687	leaf = path->nodes[0];
 688	btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 689
 690	BUG_ON(key.type == BTRFS_EXTENT_REF_V0_KEY);
 691	if (iref) {
 692		/*
 693		 * If type is invalid, we should have bailed out earlier than
 694		 * this call.
 695		 */
 696		type = btrfs_get_extent_inline_ref_type(leaf, iref, BTRFS_REF_TYPE_DATA);
 697		ASSERT(type != BTRFS_REF_TYPE_INVALID);
 698		if (type == BTRFS_EXTENT_DATA_REF_KEY) {
 699			ref1 = (struct btrfs_extent_data_ref *)(&iref->offset);
 700			num_refs = btrfs_extent_data_ref_count(leaf, ref1);
 701		} else {
 702			ref2 = (struct btrfs_shared_data_ref *)(iref + 1);
 703			num_refs = btrfs_shared_data_ref_count(leaf, ref2);
 704		}
 705	} else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
 706		ref1 = btrfs_item_ptr(leaf, path->slots[0],
 707				      struct btrfs_extent_data_ref);
 708		num_refs = btrfs_extent_data_ref_count(leaf, ref1);
 709	} else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
 710		ref2 = btrfs_item_ptr(leaf, path->slots[0],
 711				      struct btrfs_shared_data_ref);
 712		num_refs = btrfs_shared_data_ref_count(leaf, ref2);
 713	} else {
 714		WARN_ON(1);
 715	}
 716	return num_refs;
 717}
 718
 719static noinline int lookup_tree_block_ref(struct btrfs_trans_handle *trans,
 720					  struct btrfs_path *path,
 721					  u64 bytenr, u64 parent,
 722					  u64 root_objectid)
 723{
 724	struct btrfs_root *root = trans->fs_info->extent_root;
 725	struct btrfs_key key;
 726	int ret;
 727
 728	key.objectid = bytenr;
 729	if (parent) {
 730		key.type = BTRFS_SHARED_BLOCK_REF_KEY;
 731		key.offset = parent;
 732	} else {
 733		key.type = BTRFS_TREE_BLOCK_REF_KEY;
 734		key.offset = root_objectid;
 735	}
 736
 737	ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
 738	if (ret > 0)
 739		ret = -ENOENT;
 740	return ret;
 741}
 742
 743static noinline int insert_tree_block_ref(struct btrfs_trans_handle *trans,
 744					  struct btrfs_path *path,
 745					  u64 bytenr, u64 parent,
 746					  u64 root_objectid)
 747{
 
 748	struct btrfs_key key;
 749	int ret;
 750
 751	key.objectid = bytenr;
 752	if (parent) {
 753		key.type = BTRFS_SHARED_BLOCK_REF_KEY;
 754		key.offset = parent;
 755	} else {
 756		key.type = BTRFS_TREE_BLOCK_REF_KEY;
 757		key.offset = root_objectid;
 758	}
 759
 760	ret = btrfs_insert_empty_item(trans, trans->fs_info->extent_root,
 761				      path, &key, 0);
 762	btrfs_release_path(path);
 763	return ret;
 764}
 765
 766static inline int extent_ref_type(u64 parent, u64 owner)
 767{
 768	int type;
 769	if (owner < BTRFS_FIRST_FREE_OBJECTID) {
 770		if (parent > 0)
 771			type = BTRFS_SHARED_BLOCK_REF_KEY;
 772		else
 773			type = BTRFS_TREE_BLOCK_REF_KEY;
 774	} else {
 775		if (parent > 0)
 776			type = BTRFS_SHARED_DATA_REF_KEY;
 777		else
 778			type = BTRFS_EXTENT_DATA_REF_KEY;
 779	}
 780	return type;
 781}
 782
 783static int find_next_key(struct btrfs_path *path, int level,
 784			 struct btrfs_key *key)
 785
 786{
 787	for (; level < BTRFS_MAX_LEVEL; level++) {
 788		if (!path->nodes[level])
 789			break;
 790		if (path->slots[level] + 1 >=
 791		    btrfs_header_nritems(path->nodes[level]))
 792			continue;
 793		if (level == 0)
 794			btrfs_item_key_to_cpu(path->nodes[level], key,
 795					      path->slots[level] + 1);
 796		else
 797			btrfs_node_key_to_cpu(path->nodes[level], key,
 798					      path->slots[level] + 1);
 799		return 0;
 800	}
 801	return 1;
 802}
 803
 804/*
 805 * look for inline back ref. if back ref is found, *ref_ret is set
 806 * to the address of inline back ref, and 0 is returned.
 807 *
 808 * if back ref isn't found, *ref_ret is set to the address where it
 809 * should be inserted, and -ENOENT is returned.
 810 *
 811 * if insert is true and there are too many inline back refs, the path
 812 * points to the extent item, and -EAGAIN is returned.
 813 *
 814 * NOTE: inline back refs are ordered in the same way that back ref
 815 *	 items in the tree are ordered.
 816 */
 817static noinline_for_stack
 818int lookup_inline_extent_backref(struct btrfs_trans_handle *trans,
 819				 struct btrfs_path *path,
 820				 struct btrfs_extent_inline_ref **ref_ret,
 821				 u64 bytenr, u64 num_bytes,
 822				 u64 parent, u64 root_objectid,
 823				 u64 owner, u64 offset, int insert)
 824{
 825	struct btrfs_fs_info *fs_info = trans->fs_info;
 826	struct btrfs_root *root = fs_info->extent_root;
 827	struct btrfs_key key;
 828	struct extent_buffer *leaf;
 829	struct btrfs_extent_item *ei;
 830	struct btrfs_extent_inline_ref *iref;
 831	u64 flags;
 832	u64 item_size;
 833	unsigned long ptr;
 834	unsigned long end;
 835	int extra_size;
 836	int type;
 837	int want;
 838	int ret;
 839	int err = 0;
 840	bool skinny_metadata = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
 841	int needed;
 842
 843	key.objectid = bytenr;
 844	key.type = BTRFS_EXTENT_ITEM_KEY;
 845	key.offset = num_bytes;
 846
 847	want = extent_ref_type(parent, owner);
 848	if (insert) {
 849		extra_size = btrfs_extent_inline_ref_size(want);
 
 850		path->keep_locks = 1;
 851	} else
 852		extra_size = -1;
 853
 854	/*
 855	 * Owner is our level, so we can just add one to get the level for the
 856	 * block we are interested in.
 857	 */
 858	if (skinny_metadata && owner < BTRFS_FIRST_FREE_OBJECTID) {
 859		key.type = BTRFS_METADATA_ITEM_KEY;
 860		key.offset = owner;
 861	}
 862
 863again:
 864	ret = btrfs_search_slot(trans, root, &key, path, extra_size, 1);
 865	if (ret < 0) {
 866		err = ret;
 867		goto out;
 868	}
 869
 870	/*
 871	 * We may be a newly converted file system which still has the old fat
 872	 * extent entries for metadata, so try and see if we have one of those.
 873	 */
 874	if (ret > 0 && skinny_metadata) {
 875		skinny_metadata = false;
 876		if (path->slots[0]) {
 877			path->slots[0]--;
 878			btrfs_item_key_to_cpu(path->nodes[0], &key,
 879					      path->slots[0]);
 880			if (key.objectid == bytenr &&
 881			    key.type == BTRFS_EXTENT_ITEM_KEY &&
 882			    key.offset == num_bytes)
 883				ret = 0;
 884		}
 885		if (ret) {
 886			key.objectid = bytenr;
 887			key.type = BTRFS_EXTENT_ITEM_KEY;
 888			key.offset = num_bytes;
 889			btrfs_release_path(path);
 890			goto again;
 891		}
 892	}
 893
 894	if (ret && !insert) {
 895		err = -ENOENT;
 896		goto out;
 897	} else if (WARN_ON(ret)) {
 898		err = -EIO;
 899		goto out;
 900	}
 901
 902	leaf = path->nodes[0];
 903	item_size = btrfs_item_size_nr(leaf, path->slots[0]);
 904	if (unlikely(item_size < sizeof(*ei))) {
 905		err = -EINVAL;
 906		btrfs_print_v0_err(fs_info);
 907		btrfs_abort_transaction(trans, err);
 908		goto out;
 909	}
 910
 911	ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
 912	flags = btrfs_extent_flags(leaf, ei);
 913
 914	ptr = (unsigned long)(ei + 1);
 915	end = (unsigned long)ei + item_size;
 916
 917	if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK && !skinny_metadata) {
 918		ptr += sizeof(struct btrfs_tree_block_info);
 919		BUG_ON(ptr > end);
 920	}
 921
 922	if (owner >= BTRFS_FIRST_FREE_OBJECTID)
 923		needed = BTRFS_REF_TYPE_DATA;
 924	else
 925		needed = BTRFS_REF_TYPE_BLOCK;
 926
 927	err = -ENOENT;
 928	while (1) {
 929		if (ptr >= end) {
 930			WARN_ON(ptr > end);
 
 
 
 
 
 
 931			break;
 932		}
 933		iref = (struct btrfs_extent_inline_ref *)ptr;
 934		type = btrfs_get_extent_inline_ref_type(leaf, iref, needed);
 935		if (type == BTRFS_REF_TYPE_INVALID) {
 936			err = -EUCLEAN;
 937			goto out;
 938		}
 939
 940		if (want < type)
 941			break;
 942		if (want > type) {
 943			ptr += btrfs_extent_inline_ref_size(type);
 944			continue;
 945		}
 946
 947		if (type == BTRFS_EXTENT_DATA_REF_KEY) {
 948			struct btrfs_extent_data_ref *dref;
 949			dref = (struct btrfs_extent_data_ref *)(&iref->offset);
 950			if (match_extent_data_ref(leaf, dref, root_objectid,
 951						  owner, offset)) {
 952				err = 0;
 953				break;
 954			}
 955			if (hash_extent_data_ref_item(leaf, dref) <
 956			    hash_extent_data_ref(root_objectid, owner, offset))
 957				break;
 958		} else {
 959			u64 ref_offset;
 960			ref_offset = btrfs_extent_inline_ref_offset(leaf, iref);
 961			if (parent > 0) {
 962				if (parent == ref_offset) {
 963					err = 0;
 964					break;
 965				}
 966				if (ref_offset < parent)
 967					break;
 968			} else {
 969				if (root_objectid == ref_offset) {
 970					err = 0;
 971					break;
 972				}
 973				if (ref_offset < root_objectid)
 974					break;
 975			}
 976		}
 977		ptr += btrfs_extent_inline_ref_size(type);
 978	}
 979	if (err == -ENOENT && insert) {
 980		if (item_size + extra_size >=
 981		    BTRFS_MAX_EXTENT_ITEM_SIZE(root)) {
 982			err = -EAGAIN;
 983			goto out;
 984		}
 985		/*
 986		 * To add new inline back ref, we have to make sure
 987		 * there is no corresponding back ref item.
 988		 * For simplicity, we just do not add new inline back
 989		 * ref if there is any kind of item for this block
 990		 */
 991		if (find_next_key(path, 0, &key) == 0 &&
 992		    key.objectid == bytenr &&
 993		    key.type < BTRFS_BLOCK_GROUP_ITEM_KEY) {
 994			err = -EAGAIN;
 995			goto out;
 996		}
 997	}
 998	*ref_ret = (struct btrfs_extent_inline_ref *)ptr;
 999out:
1000	if (insert) {
1001		path->keep_locks = 0;
 
1002		btrfs_unlock_up_safe(path, 1);
1003	}
1004	return err;
1005}
1006
1007/*
1008 * helper to add new inline back ref
1009 */
1010static noinline_for_stack
1011void setup_inline_extent_backref(struct btrfs_fs_info *fs_info,
1012				 struct btrfs_path *path,
1013				 struct btrfs_extent_inline_ref *iref,
1014				 u64 parent, u64 root_objectid,
1015				 u64 owner, u64 offset, int refs_to_add,
1016				 struct btrfs_delayed_extent_op *extent_op)
1017{
1018	struct extent_buffer *leaf;
1019	struct btrfs_extent_item *ei;
1020	unsigned long ptr;
1021	unsigned long end;
1022	unsigned long item_offset;
1023	u64 refs;
1024	int size;
1025	int type;
1026
1027	leaf = path->nodes[0];
1028	ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1029	item_offset = (unsigned long)iref - (unsigned long)ei;
1030
1031	type = extent_ref_type(parent, owner);
1032	size = btrfs_extent_inline_ref_size(type);
1033
1034	btrfs_extend_item(path, size);
1035
1036	ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1037	refs = btrfs_extent_refs(leaf, ei);
1038	refs += refs_to_add;
1039	btrfs_set_extent_refs(leaf, ei, refs);
1040	if (extent_op)
1041		__run_delayed_extent_op(extent_op, leaf, ei);
1042
1043	ptr = (unsigned long)ei + item_offset;
1044	end = (unsigned long)ei + btrfs_item_size_nr(leaf, path->slots[0]);
1045	if (ptr < end - size)
1046		memmove_extent_buffer(leaf, ptr + size, ptr,
1047				      end - size - ptr);
1048
1049	iref = (struct btrfs_extent_inline_ref *)ptr;
1050	btrfs_set_extent_inline_ref_type(leaf, iref, type);
1051	if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1052		struct btrfs_extent_data_ref *dref;
1053		dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1054		btrfs_set_extent_data_ref_root(leaf, dref, root_objectid);
1055		btrfs_set_extent_data_ref_objectid(leaf, dref, owner);
1056		btrfs_set_extent_data_ref_offset(leaf, dref, offset);
1057		btrfs_set_extent_data_ref_count(leaf, dref, refs_to_add);
1058	} else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1059		struct btrfs_shared_data_ref *sref;
1060		sref = (struct btrfs_shared_data_ref *)(iref + 1);
1061		btrfs_set_shared_data_ref_count(leaf, sref, refs_to_add);
1062		btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1063	} else if (type == BTRFS_SHARED_BLOCK_REF_KEY) {
1064		btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1065	} else {
1066		btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
1067	}
1068	btrfs_mark_buffer_dirty(leaf);
1069}
1070
1071static int lookup_extent_backref(struct btrfs_trans_handle *trans,
1072				 struct btrfs_path *path,
1073				 struct btrfs_extent_inline_ref **ref_ret,
1074				 u64 bytenr, u64 num_bytes, u64 parent,
1075				 u64 root_objectid, u64 owner, u64 offset)
1076{
1077	int ret;
1078
1079	ret = lookup_inline_extent_backref(trans, path, ref_ret, bytenr,
1080					   num_bytes, parent, root_objectid,
1081					   owner, offset, 0);
1082	if (ret != -ENOENT)
1083		return ret;
1084
1085	btrfs_release_path(path);
1086	*ref_ret = NULL;
1087
1088	if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1089		ret = lookup_tree_block_ref(trans, path, bytenr, parent,
1090					    root_objectid);
1091	} else {
1092		ret = lookup_extent_data_ref(trans, path, bytenr, parent,
1093					     root_objectid, owner, offset);
1094	}
1095	return ret;
1096}
1097
1098/*
1099 * helper to update/remove inline back ref
1100 */
1101static noinline_for_stack
1102void update_inline_extent_backref(struct btrfs_path *path,
1103				  struct btrfs_extent_inline_ref *iref,
1104				  int refs_to_mod,
1105				  struct btrfs_delayed_extent_op *extent_op,
1106				  int *last_ref)
1107{
1108	struct extent_buffer *leaf = path->nodes[0];
1109	struct btrfs_extent_item *ei;
1110	struct btrfs_extent_data_ref *dref = NULL;
1111	struct btrfs_shared_data_ref *sref = NULL;
1112	unsigned long ptr;
1113	unsigned long end;
1114	u32 item_size;
1115	int size;
1116	int type;
1117	u64 refs;
1118
1119	ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1120	refs = btrfs_extent_refs(leaf, ei);
1121	WARN_ON(refs_to_mod < 0 && refs + refs_to_mod <= 0);
1122	refs += refs_to_mod;
1123	btrfs_set_extent_refs(leaf, ei, refs);
1124	if (extent_op)
1125		__run_delayed_extent_op(extent_op, leaf, ei);
1126
1127	/*
1128	 * If type is invalid, we should have bailed out after
1129	 * lookup_inline_extent_backref().
1130	 */
1131	type = btrfs_get_extent_inline_ref_type(leaf, iref, BTRFS_REF_TYPE_ANY);
1132	ASSERT(type != BTRFS_REF_TYPE_INVALID);
1133
1134	if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1135		dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1136		refs = btrfs_extent_data_ref_count(leaf, dref);
1137	} else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1138		sref = (struct btrfs_shared_data_ref *)(iref + 1);
1139		refs = btrfs_shared_data_ref_count(leaf, sref);
1140	} else {
1141		refs = 1;
1142		BUG_ON(refs_to_mod != -1);
1143	}
1144
1145	BUG_ON(refs_to_mod < 0 && refs < -refs_to_mod);
1146	refs += refs_to_mod;
1147
1148	if (refs > 0) {
1149		if (type == BTRFS_EXTENT_DATA_REF_KEY)
1150			btrfs_set_extent_data_ref_count(leaf, dref, refs);
1151		else
1152			btrfs_set_shared_data_ref_count(leaf, sref, refs);
1153	} else {
1154		*last_ref = 1;
1155		size =  btrfs_extent_inline_ref_size(type);
1156		item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1157		ptr = (unsigned long)iref;
1158		end = (unsigned long)ei + item_size;
1159		if (ptr + size < end)
1160			memmove_extent_buffer(leaf, ptr, ptr + size,
1161					      end - ptr - size);
1162		item_size -= size;
1163		btrfs_truncate_item(path, item_size, 1);
1164	}
1165	btrfs_mark_buffer_dirty(leaf);
1166}
1167
1168static noinline_for_stack
1169int insert_inline_extent_backref(struct btrfs_trans_handle *trans,
1170				 struct btrfs_path *path,
1171				 u64 bytenr, u64 num_bytes, u64 parent,
1172				 u64 root_objectid, u64 owner,
1173				 u64 offset, int refs_to_add,
1174				 struct btrfs_delayed_extent_op *extent_op)
1175{
1176	struct btrfs_extent_inline_ref *iref;
1177	int ret;
1178
1179	ret = lookup_inline_extent_backref(trans, path, &iref, bytenr,
1180					   num_bytes, parent, root_objectid,
1181					   owner, offset, 1);
1182	if (ret == 0) {
1183		BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID);
1184		update_inline_extent_backref(path, iref, refs_to_add,
1185					     extent_op, NULL);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1186	} else if (ret == -ENOENT) {
1187		setup_inline_extent_backref(trans->fs_info, path, iref, parent,
1188					    root_objectid, owner, offset,
1189					    refs_to_add, extent_op);
1190		ret = 0;
1191	}
1192	return ret;
1193}
1194
1195static int insert_extent_backref(struct btrfs_trans_handle *trans,
1196				 struct btrfs_path *path,
1197				 u64 bytenr, u64 parent, u64 root_objectid,
1198				 u64 owner, u64 offset, int refs_to_add)
1199{
1200	int ret;
1201	if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1202		BUG_ON(refs_to_add != 1);
1203		ret = insert_tree_block_ref(trans, path, bytenr, parent,
1204					    root_objectid);
1205	} else {
1206		ret = insert_extent_data_ref(trans, path, bytenr, parent,
1207					     root_objectid, owner, offset,
1208					     refs_to_add);
1209	}
1210	return ret;
1211}
1212
1213static int remove_extent_backref(struct btrfs_trans_handle *trans,
 
1214				 struct btrfs_path *path,
1215				 struct btrfs_extent_inline_ref *iref,
1216				 int refs_to_drop, int is_data, int *last_ref)
1217{
1218	int ret = 0;
1219
1220	BUG_ON(!is_data && refs_to_drop != 1);
1221	if (iref) {
1222		update_inline_extent_backref(path, iref, -refs_to_drop, NULL,
1223					     last_ref);
1224	} else if (is_data) {
1225		ret = remove_extent_data_ref(trans, path, refs_to_drop,
1226					     last_ref);
1227	} else {
1228		*last_ref = 1;
1229		ret = btrfs_del_item(trans, trans->fs_info->extent_root, path);
1230	}
1231	return ret;
1232}
1233
1234static int btrfs_issue_discard(struct block_device *bdev, u64 start, u64 len,
1235			       u64 *discarded_bytes)
1236{
1237	int j, ret = 0;
1238	u64 bytes_left, end;
1239	u64 aligned_start = ALIGN(start, 1 << 9);
1240
1241	if (WARN_ON(start != aligned_start)) {
1242		len -= aligned_start - start;
1243		len = round_down(len, 1 << 9);
1244		start = aligned_start;
1245	}
1246
1247	*discarded_bytes = 0;
1248
1249	if (!len)
1250		return 0;
1251
1252	end = start + len;
1253	bytes_left = len;
1254
1255	/* Skip any superblocks on this device. */
1256	for (j = 0; j < BTRFS_SUPER_MIRROR_MAX; j++) {
1257		u64 sb_start = btrfs_sb_offset(j);
1258		u64 sb_end = sb_start + BTRFS_SUPER_INFO_SIZE;
1259		u64 size = sb_start - start;
1260
1261		if (!in_range(sb_start, start, bytes_left) &&
1262		    !in_range(sb_end, start, bytes_left) &&
1263		    !in_range(start, sb_start, BTRFS_SUPER_INFO_SIZE))
1264			continue;
1265
1266		/*
1267		 * Superblock spans beginning of range.  Adjust start and
1268		 * try again.
1269		 */
1270		if (sb_start <= start) {
1271			start += sb_end - start;
1272			if (start > end) {
1273				bytes_left = 0;
1274				break;
1275			}
1276			bytes_left = end - start;
1277			continue;
1278		}
1279
1280		if (size) {
1281			ret = blkdev_issue_discard(bdev, start >> 9, size >> 9,
1282						   GFP_NOFS, 0);
1283			if (!ret)
1284				*discarded_bytes += size;
1285			else if (ret != -EOPNOTSUPP)
1286				return ret;
1287		}
1288
1289		start = sb_end;
1290		if (start > end) {
1291			bytes_left = 0;
1292			break;
1293		}
1294		bytes_left = end - start;
1295	}
1296
1297	if (bytes_left) {
1298		ret = blkdev_issue_discard(bdev, start >> 9, bytes_left >> 9,
1299					   GFP_NOFS, 0);
1300		if (!ret)
1301			*discarded_bytes += bytes_left;
1302	}
1303	return ret;
1304}
1305
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1306int btrfs_discard_extent(struct btrfs_fs_info *fs_info, u64 bytenr,
1307			 u64 num_bytes, u64 *actual_bytes)
1308{
1309	int ret;
1310	u64 discarded_bytes = 0;
1311	struct btrfs_bio *bbio = NULL;
1312
1313
1314	/*
1315	 * Avoid races with device replace and make sure our bbio has devices
1316	 * associated to its stripes that don't go away while we are discarding.
1317	 */
1318	btrfs_bio_counter_inc_blocked(fs_info);
1319	/* Tell the block device(s) that the sectors can be discarded */
1320	ret = btrfs_map_block(fs_info, BTRFS_MAP_DISCARD, bytenr, &num_bytes,
1321			      &bbio, 0);
1322	/* Error condition is -ENOMEM */
1323	if (!ret) {
1324		struct btrfs_bio_stripe *stripe = bbio->stripes;
1325		int i;
1326
 
 
 
 
 
 
 
 
1327
1328		for (i = 0; i < bbio->num_stripes; i++, stripe++) {
 
1329			u64 bytes;
1330			struct request_queue *req_q;
1331
1332			if (!stripe->dev->bdev) {
1333				ASSERT(btrfs_test_opt(fs_info, DEGRADED));
1334				continue;
1335			}
1336			req_q = bdev_get_queue(stripe->dev->bdev);
1337			if (!blk_queue_discard(req_q))
 
1338				continue;
1339
1340			ret = btrfs_issue_discard(stripe->dev->bdev,
1341						  stripe->physical,
1342						  stripe->length,
1343						  &bytes);
1344			if (!ret)
 
 
 
 
 
1345				discarded_bytes += bytes;
1346			else if (ret != -EOPNOTSUPP)
1347				break; /* Logic errors or -ENOMEM, or -EIO but I don't know how that could happen JDM */
1348
1349			/*
1350			 * Just in case we get back EOPNOTSUPP for some reason,
1351			 * just ignore the return value so we don't screw up
1352			 * people calling discard_extent.
1353			 */
1354			ret = 0;
1355		}
1356		btrfs_put_bbio(bbio);
 
 
 
1357	}
1358	btrfs_bio_counter_dec(fs_info);
1359
1360	if (actual_bytes)
1361		*actual_bytes = discarded_bytes;
1362
1363
1364	if (ret == -EOPNOTSUPP)
1365		ret = 0;
1366	return ret;
1367}
1368
1369/* Can return -ENOMEM */
1370int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
1371			 struct btrfs_ref *generic_ref)
1372{
1373	struct btrfs_fs_info *fs_info = trans->fs_info;
1374	int old_ref_mod, new_ref_mod;
1375	int ret;
1376
1377	ASSERT(generic_ref->type != BTRFS_REF_NOT_SET &&
1378	       generic_ref->action);
1379	BUG_ON(generic_ref->type == BTRFS_REF_METADATA &&
1380	       generic_ref->tree_ref.root == BTRFS_TREE_LOG_OBJECTID);
1381
1382	if (generic_ref->type == BTRFS_REF_METADATA)
1383		ret = btrfs_add_delayed_tree_ref(trans, generic_ref,
1384				NULL, &old_ref_mod, &new_ref_mod);
1385	else
1386		ret = btrfs_add_delayed_data_ref(trans, generic_ref, 0,
1387						 &old_ref_mod, &new_ref_mod);
1388
1389	btrfs_ref_tree_mod(fs_info, generic_ref);
1390
1391	if (ret == 0 && old_ref_mod < 0 && new_ref_mod >= 0)
1392		sub_pinned_bytes(fs_info, generic_ref);
1393
1394	return ret;
1395}
1396
1397/*
1398 * __btrfs_inc_extent_ref - insert backreference for a given extent
1399 *
 
 
 
1400 * @trans:	    Handle of transaction
1401 *
1402 * @node:	    The delayed ref node used to get the bytenr/length for
1403 *		    extent whose references are incremented.
1404 *
1405 * @parent:	    If this is a shared extent (BTRFS_SHARED_DATA_REF_KEY/
1406 *		    BTRFS_SHARED_BLOCK_REF_KEY) then it holds the logical
1407 *		    bytenr of the parent block. Since new extents are always
1408 *		    created with indirect references, this will only be the case
1409 *		    when relocating a shared extent. In that case, root_objectid
1410 *		    will be BTRFS_TREE_RELOC_OBJECTID. Otheriwse, parent must
1411 *		    be 0
1412 *
1413 * @root_objectid:  The id of the root where this modification has originated,
1414 *		    this can be either one of the well-known metadata trees or
1415 *		    the subvolume id which references this extent.
1416 *
1417 * @owner:	    For data extents it is the inode number of the owning file.
1418 *		    For metadata extents this parameter holds the level in the
1419 *		    tree of the extent.
1420 *
1421 * @offset:	    For metadata extents the offset is ignored and is currently
1422 *		    always passed as 0. For data extents it is the fileoffset
1423 *		    this extent belongs to.
1424 *
1425 * @refs_to_add     Number of references to add
1426 *
1427 * @extent_op       Pointer to a structure, holding information necessary when
1428 *                  updating a tree block's flags
1429 *
1430 */
1431static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
1432				  struct btrfs_delayed_ref_node *node,
1433				  u64 parent, u64 root_objectid,
1434				  u64 owner, u64 offset, int refs_to_add,
1435				  struct btrfs_delayed_extent_op *extent_op)
1436{
1437	struct btrfs_path *path;
1438	struct extent_buffer *leaf;
1439	struct btrfs_extent_item *item;
1440	struct btrfs_key key;
1441	u64 bytenr = node->bytenr;
1442	u64 num_bytes = node->num_bytes;
1443	u64 refs;
1444	int ret;
1445
1446	path = btrfs_alloc_path();
1447	if (!path)
1448		return -ENOMEM;
1449
1450	path->reada = READA_FORWARD;
1451	path->leave_spinning = 1;
1452	/* this will setup the path even if it fails to insert the back ref */
1453	ret = insert_inline_extent_backref(trans, path, bytenr, num_bytes,
1454					   parent, root_objectid, owner,
1455					   offset, refs_to_add, extent_op);
1456	if ((ret < 0 && ret != -EAGAIN) || !ret)
1457		goto out;
1458
1459	/*
1460	 * Ok we had -EAGAIN which means we didn't have space to insert and
1461	 * inline extent ref, so just update the reference count and add a
1462	 * normal backref.
1463	 */
1464	leaf = path->nodes[0];
1465	btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1466	item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1467	refs = btrfs_extent_refs(leaf, item);
1468	btrfs_set_extent_refs(leaf, item, refs + refs_to_add);
1469	if (extent_op)
1470		__run_delayed_extent_op(extent_op, leaf, item);
1471
1472	btrfs_mark_buffer_dirty(leaf);
1473	btrfs_release_path(path);
1474
1475	path->reada = READA_FORWARD;
1476	path->leave_spinning = 1;
1477	/* now insert the actual backref */
1478	ret = insert_extent_backref(trans, path, bytenr, parent, root_objectid,
1479				    owner, offset, refs_to_add);
 
 
 
 
 
 
 
1480	if (ret)
1481		btrfs_abort_transaction(trans, ret);
1482out:
1483	btrfs_free_path(path);
1484	return ret;
1485}
1486
1487static int run_delayed_data_ref(struct btrfs_trans_handle *trans,
1488				struct btrfs_delayed_ref_node *node,
1489				struct btrfs_delayed_extent_op *extent_op,
1490				int insert_reserved)
1491{
1492	int ret = 0;
1493	struct btrfs_delayed_data_ref *ref;
1494	struct btrfs_key ins;
1495	u64 parent = 0;
1496	u64 ref_root = 0;
1497	u64 flags = 0;
1498
1499	ins.objectid = node->bytenr;
1500	ins.offset = node->num_bytes;
1501	ins.type = BTRFS_EXTENT_ITEM_KEY;
1502
1503	ref = btrfs_delayed_node_to_data_ref(node);
1504	trace_run_delayed_data_ref(trans->fs_info, node, ref, node->action);
1505
1506	if (node->type == BTRFS_SHARED_DATA_REF_KEY)
1507		parent = ref->parent;
1508	ref_root = ref->root;
1509
1510	if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
1511		if (extent_op)
1512			flags |= extent_op->flags_to_set;
1513		ret = alloc_reserved_file_extent(trans, parent, ref_root,
1514						 flags, ref->objectid,
1515						 ref->offset, &ins,
1516						 node->ref_mod);
1517	} else if (node->action == BTRFS_ADD_DELAYED_REF) {
1518		ret = __btrfs_inc_extent_ref(trans, node, parent, ref_root,
1519					     ref->objectid, ref->offset,
1520					     node->ref_mod, extent_op);
1521	} else if (node->action == BTRFS_DROP_DELAYED_REF) {
1522		ret = __btrfs_free_extent(trans, node, parent,
1523					  ref_root, ref->objectid,
1524					  ref->offset, node->ref_mod,
1525					  extent_op);
1526	} else {
1527		BUG();
1528	}
1529	return ret;
1530}
1531
1532static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
1533				    struct extent_buffer *leaf,
1534				    struct btrfs_extent_item *ei)
1535{
1536	u64 flags = btrfs_extent_flags(leaf, ei);
1537	if (extent_op->update_flags) {
1538		flags |= extent_op->flags_to_set;
1539		btrfs_set_extent_flags(leaf, ei, flags);
1540	}
1541
1542	if (extent_op->update_key) {
1543		struct btrfs_tree_block_info *bi;
1544		BUG_ON(!(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK));
1545		bi = (struct btrfs_tree_block_info *)(ei + 1);
1546		btrfs_set_tree_block_key(leaf, bi, &extent_op->key);
1547	}
1548}
1549
1550static int run_delayed_extent_op(struct btrfs_trans_handle *trans,
1551				 struct btrfs_delayed_ref_head *head,
1552				 struct btrfs_delayed_extent_op *extent_op)
1553{
1554	struct btrfs_fs_info *fs_info = trans->fs_info;
 
1555	struct btrfs_key key;
1556	struct btrfs_path *path;
1557	struct btrfs_extent_item *ei;
1558	struct extent_buffer *leaf;
1559	u32 item_size;
1560	int ret;
1561	int err = 0;
1562	int metadata = !extent_op->is_data;
1563
1564	if (trans->aborted)
1565		return 0;
1566
1567	if (metadata && !btrfs_fs_incompat(fs_info, SKINNY_METADATA))
1568		metadata = 0;
1569
1570	path = btrfs_alloc_path();
1571	if (!path)
1572		return -ENOMEM;
1573
1574	key.objectid = head->bytenr;
1575
1576	if (metadata) {
1577		key.type = BTRFS_METADATA_ITEM_KEY;
1578		key.offset = extent_op->level;
1579	} else {
1580		key.type = BTRFS_EXTENT_ITEM_KEY;
1581		key.offset = head->num_bytes;
1582	}
1583
 
1584again:
1585	path->reada = READA_FORWARD;
1586	path->leave_spinning = 1;
1587	ret = btrfs_search_slot(trans, fs_info->extent_root, &key, path, 0, 1);
1588	if (ret < 0) {
1589		err = ret;
1590		goto out;
1591	}
1592	if (ret > 0) {
1593		if (metadata) {
1594			if (path->slots[0] > 0) {
1595				path->slots[0]--;
1596				btrfs_item_key_to_cpu(path->nodes[0], &key,
1597						      path->slots[0]);
1598				if (key.objectid == head->bytenr &&
1599				    key.type == BTRFS_EXTENT_ITEM_KEY &&
1600				    key.offset == head->num_bytes)
1601					ret = 0;
1602			}
1603			if (ret > 0) {
1604				btrfs_release_path(path);
1605				metadata = 0;
1606
1607				key.objectid = head->bytenr;
1608				key.offset = head->num_bytes;
1609				key.type = BTRFS_EXTENT_ITEM_KEY;
1610				goto again;
1611			}
1612		} else {
1613			err = -EIO;
1614			goto out;
1615		}
1616	}
1617
1618	leaf = path->nodes[0];
1619	item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1620
1621	if (unlikely(item_size < sizeof(*ei))) {
1622		err = -EINVAL;
1623		btrfs_print_v0_err(fs_info);
1624		btrfs_abort_transaction(trans, err);
1625		goto out;
1626	}
1627
1628	ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1629	__run_delayed_extent_op(extent_op, leaf, ei);
1630
1631	btrfs_mark_buffer_dirty(leaf);
1632out:
1633	btrfs_free_path(path);
1634	return err;
1635}
1636
1637static int run_delayed_tree_ref(struct btrfs_trans_handle *trans,
1638				struct btrfs_delayed_ref_node *node,
1639				struct btrfs_delayed_extent_op *extent_op,
1640				int insert_reserved)
1641{
1642	int ret = 0;
1643	struct btrfs_delayed_tree_ref *ref;
1644	u64 parent = 0;
1645	u64 ref_root = 0;
1646
1647	ref = btrfs_delayed_node_to_tree_ref(node);
1648	trace_run_delayed_tree_ref(trans->fs_info, node, ref, node->action);
1649
1650	if (node->type == BTRFS_SHARED_BLOCK_REF_KEY)
1651		parent = ref->parent;
1652	ref_root = ref->root;
1653
1654	if (node->ref_mod != 1) {
1655		btrfs_err(trans->fs_info,
1656	"btree block(%llu) has %d references rather than 1: action %d ref_root %llu parent %llu",
1657			  node->bytenr, node->ref_mod, node->action, ref_root,
1658			  parent);
1659		return -EIO;
1660	}
1661	if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
1662		BUG_ON(!extent_op || !extent_op->update_flags);
1663		ret = alloc_reserved_tree_block(trans, node, extent_op);
1664	} else if (node->action == BTRFS_ADD_DELAYED_REF) {
1665		ret = __btrfs_inc_extent_ref(trans, node, parent, ref_root,
1666					     ref->level, 0, 1, extent_op);
1667	} else if (node->action == BTRFS_DROP_DELAYED_REF) {
1668		ret = __btrfs_free_extent(trans, node, parent, ref_root,
1669					  ref->level, 0, 1, extent_op);
1670	} else {
1671		BUG();
1672	}
1673	return ret;
1674}
1675
1676/* helper function to actually process a single delayed ref entry */
1677static int run_one_delayed_ref(struct btrfs_trans_handle *trans,
1678			       struct btrfs_delayed_ref_node *node,
1679			       struct btrfs_delayed_extent_op *extent_op,
1680			       int insert_reserved)
1681{
1682	int ret = 0;
1683
1684	if (trans->aborted) {
1685		if (insert_reserved)
1686			btrfs_pin_extent(trans->fs_info, node->bytenr,
1687					 node->num_bytes, 1);
1688		return 0;
1689	}
1690
1691	if (node->type == BTRFS_TREE_BLOCK_REF_KEY ||
1692	    node->type == BTRFS_SHARED_BLOCK_REF_KEY)
1693		ret = run_delayed_tree_ref(trans, node, extent_op,
1694					   insert_reserved);
1695	else if (node->type == BTRFS_EXTENT_DATA_REF_KEY ||
1696		 node->type == BTRFS_SHARED_DATA_REF_KEY)
1697		ret = run_delayed_data_ref(trans, node, extent_op,
1698					   insert_reserved);
1699	else
1700		BUG();
1701	if (ret && insert_reserved)
1702		btrfs_pin_extent(trans->fs_info, node->bytenr,
1703				 node->num_bytes, 1);
 
 
 
 
1704	return ret;
1705}
1706
1707static inline struct btrfs_delayed_ref_node *
1708select_delayed_ref(struct btrfs_delayed_ref_head *head)
1709{
1710	struct btrfs_delayed_ref_node *ref;
1711
1712	if (RB_EMPTY_ROOT(&head->ref_tree.rb_root))
1713		return NULL;
1714
1715	/*
1716	 * Select a delayed ref of type BTRFS_ADD_DELAYED_REF first.
1717	 * This is to prevent a ref count from going down to zero, which deletes
1718	 * the extent item from the extent tree, when there still are references
1719	 * to add, which would fail because they would not find the extent item.
1720	 */
1721	if (!list_empty(&head->ref_add_list))
1722		return list_first_entry(&head->ref_add_list,
1723				struct btrfs_delayed_ref_node, add_list);
1724
1725	ref = rb_entry(rb_first_cached(&head->ref_tree),
1726		       struct btrfs_delayed_ref_node, ref_node);
1727	ASSERT(list_empty(&ref->add_list));
1728	return ref;
1729}
1730
1731static void unselect_delayed_ref_head(struct btrfs_delayed_ref_root *delayed_refs,
1732				      struct btrfs_delayed_ref_head *head)
1733{
1734	spin_lock(&delayed_refs->lock);
1735	head->processing = 0;
1736	delayed_refs->num_heads_ready++;
1737	spin_unlock(&delayed_refs->lock);
1738	btrfs_delayed_ref_unlock(head);
1739}
1740
1741static struct btrfs_delayed_extent_op *cleanup_extent_op(
1742				struct btrfs_delayed_ref_head *head)
1743{
1744	struct btrfs_delayed_extent_op *extent_op = head->extent_op;
1745
1746	if (!extent_op)
1747		return NULL;
1748
1749	if (head->must_insert_reserved) {
1750		head->extent_op = NULL;
1751		btrfs_free_delayed_extent_op(extent_op);
1752		return NULL;
1753	}
1754	return extent_op;
1755}
1756
1757static int run_and_cleanup_extent_op(struct btrfs_trans_handle *trans,
1758				     struct btrfs_delayed_ref_head *head)
1759{
1760	struct btrfs_delayed_extent_op *extent_op;
1761	int ret;
1762
1763	extent_op = cleanup_extent_op(head);
1764	if (!extent_op)
1765		return 0;
1766	head->extent_op = NULL;
1767	spin_unlock(&head->lock);
1768	ret = run_delayed_extent_op(trans, head, extent_op);
1769	btrfs_free_delayed_extent_op(extent_op);
1770	return ret ? ret : 1;
1771}
1772
1773void btrfs_cleanup_ref_head_accounting(struct btrfs_fs_info *fs_info,
1774				  struct btrfs_delayed_ref_root *delayed_refs,
1775				  struct btrfs_delayed_ref_head *head)
1776{
1777	int nr_items = 1;	/* Dropping this ref head update. */
1778
1779	if (head->total_ref_mod < 0) {
1780		struct btrfs_space_info *space_info;
1781		u64 flags;
1782
1783		if (head->is_data)
1784			flags = BTRFS_BLOCK_GROUP_DATA;
1785		else if (head->is_system)
1786			flags = BTRFS_BLOCK_GROUP_SYSTEM;
1787		else
1788			flags = BTRFS_BLOCK_GROUP_METADATA;
1789		space_info = btrfs_find_space_info(fs_info, flags);
1790		ASSERT(space_info);
1791		percpu_counter_add_batch(&space_info->total_bytes_pinned,
1792				   -head->num_bytes,
1793				   BTRFS_TOTAL_BYTES_PINNED_BATCH);
1794
1795		/*
1796		 * We had csum deletions accounted for in our delayed refs rsv,
1797		 * we need to drop the csum leaves for this update from our
1798		 * delayed_refs_rsv.
1799		 */
1800		if (head->is_data) {
1801			spin_lock(&delayed_refs->lock);
1802			delayed_refs->pending_csums -= head->num_bytes;
1803			spin_unlock(&delayed_refs->lock);
1804			nr_items += btrfs_csum_bytes_to_leaves(fs_info,
1805				head->num_bytes);
1806		}
1807	}
1808
1809	btrfs_delayed_refs_rsv_release(fs_info, nr_items);
1810}
1811
1812static int cleanup_ref_head(struct btrfs_trans_handle *trans,
1813			    struct btrfs_delayed_ref_head *head)
1814{
1815
1816	struct btrfs_fs_info *fs_info = trans->fs_info;
1817	struct btrfs_delayed_ref_root *delayed_refs;
1818	int ret;
1819
1820	delayed_refs = &trans->transaction->delayed_refs;
1821
1822	ret = run_and_cleanup_extent_op(trans, head);
1823	if (ret < 0) {
1824		unselect_delayed_ref_head(delayed_refs, head);
1825		btrfs_debug(fs_info, "run_delayed_extent_op returned %d", ret);
1826		return ret;
1827	} else if (ret) {
1828		return ret;
1829	}
1830
1831	/*
1832	 * Need to drop our head ref lock and re-acquire the delayed ref lock
1833	 * and then re-check to make sure nobody got added.
1834	 */
1835	spin_unlock(&head->lock);
1836	spin_lock(&delayed_refs->lock);
1837	spin_lock(&head->lock);
1838	if (!RB_EMPTY_ROOT(&head->ref_tree.rb_root) || head->extent_op) {
1839		spin_unlock(&head->lock);
1840		spin_unlock(&delayed_refs->lock);
1841		return 1;
1842	}
1843	btrfs_delete_ref_head(delayed_refs, head);
1844	spin_unlock(&head->lock);
1845	spin_unlock(&delayed_refs->lock);
1846
1847	if (head->must_insert_reserved) {
1848		btrfs_pin_extent(fs_info, head->bytenr,
1849				 head->num_bytes, 1);
1850		if (head->is_data) {
1851			ret = btrfs_del_csums(trans, fs_info, head->bytenr,
 
 
 
1852					      head->num_bytes);
1853		}
1854	}
1855
1856	btrfs_cleanup_ref_head_accounting(fs_info, delayed_refs, head);
1857
1858	trace_run_delayed_ref_head(fs_info, head, 0);
1859	btrfs_delayed_ref_unlock(head);
1860	btrfs_put_delayed_ref_head(head);
1861	return 0;
1862}
1863
1864static struct btrfs_delayed_ref_head *btrfs_obtain_ref_head(
1865					struct btrfs_trans_handle *trans)
1866{
1867	struct btrfs_delayed_ref_root *delayed_refs =
1868		&trans->transaction->delayed_refs;
1869	struct btrfs_delayed_ref_head *head = NULL;
1870	int ret;
1871
1872	spin_lock(&delayed_refs->lock);
1873	head = btrfs_select_ref_head(delayed_refs);
1874	if (!head) {
1875		spin_unlock(&delayed_refs->lock);
1876		return head;
1877	}
1878
1879	/*
1880	 * Grab the lock that says we are going to process all the refs for
1881	 * this head
1882	 */
1883	ret = btrfs_delayed_ref_lock(delayed_refs, head);
1884	spin_unlock(&delayed_refs->lock);
1885
1886	/*
1887	 * We may have dropped the spin lock to get the head mutex lock, and
1888	 * that might have given someone else time to free the head.  If that's
1889	 * true, it has been removed from our list and we can move on.
1890	 */
1891	if (ret == -EAGAIN)
1892		head = ERR_PTR(-EAGAIN);
1893
1894	return head;
1895}
1896
1897static int btrfs_run_delayed_refs_for_head(struct btrfs_trans_handle *trans,
1898				    struct btrfs_delayed_ref_head *locked_ref,
1899				    unsigned long *run_refs)
1900{
1901	struct btrfs_fs_info *fs_info = trans->fs_info;
1902	struct btrfs_delayed_ref_root *delayed_refs;
1903	struct btrfs_delayed_extent_op *extent_op;
1904	struct btrfs_delayed_ref_node *ref;
1905	int must_insert_reserved = 0;
1906	int ret;
1907
1908	delayed_refs = &trans->transaction->delayed_refs;
1909
1910	lockdep_assert_held(&locked_ref->mutex);
1911	lockdep_assert_held(&locked_ref->lock);
1912
1913	while ((ref = select_delayed_ref(locked_ref))) {
1914		if (ref->seq &&
1915		    btrfs_check_delayed_seq(fs_info, ref->seq)) {
1916			spin_unlock(&locked_ref->lock);
1917			unselect_delayed_ref_head(delayed_refs, locked_ref);
1918			return -EAGAIN;
1919		}
1920
1921		(*run_refs)++;
1922		ref->in_tree = 0;
1923		rb_erase_cached(&ref->ref_node, &locked_ref->ref_tree);
1924		RB_CLEAR_NODE(&ref->ref_node);
1925		if (!list_empty(&ref->add_list))
1926			list_del(&ref->add_list);
1927		/*
1928		 * When we play the delayed ref, also correct the ref_mod on
1929		 * head
1930		 */
1931		switch (ref->action) {
1932		case BTRFS_ADD_DELAYED_REF:
1933		case BTRFS_ADD_DELAYED_EXTENT:
1934			locked_ref->ref_mod -= ref->ref_mod;
1935			break;
1936		case BTRFS_DROP_DELAYED_REF:
1937			locked_ref->ref_mod += ref->ref_mod;
1938			break;
1939		default:
1940			WARN_ON(1);
1941		}
1942		atomic_dec(&delayed_refs->num_entries);
1943
1944		/*
1945		 * Record the must_insert_reserved flag before we drop the
1946		 * spin lock.
1947		 */
1948		must_insert_reserved = locked_ref->must_insert_reserved;
1949		locked_ref->must_insert_reserved = 0;
1950
1951		extent_op = locked_ref->extent_op;
1952		locked_ref->extent_op = NULL;
1953		spin_unlock(&locked_ref->lock);
1954
1955		ret = run_one_delayed_ref(trans, ref, extent_op,
1956					  must_insert_reserved);
1957
1958		btrfs_free_delayed_extent_op(extent_op);
1959		if (ret) {
1960			unselect_delayed_ref_head(delayed_refs, locked_ref);
1961			btrfs_put_delayed_ref(ref);
1962			btrfs_debug(fs_info, "run_one_delayed_ref returned %d",
1963				    ret);
1964			return ret;
1965		}
1966
1967		btrfs_put_delayed_ref(ref);
1968		cond_resched();
1969
1970		spin_lock(&locked_ref->lock);
1971		btrfs_merge_delayed_refs(trans, delayed_refs, locked_ref);
1972	}
1973
1974	return 0;
1975}
1976
1977/*
1978 * Returns 0 on success or if called with an already aborted transaction.
1979 * Returns -ENOMEM or -EIO on failure and will abort the transaction.
1980 */
1981static noinline int __btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
1982					     unsigned long nr)
1983{
1984	struct btrfs_fs_info *fs_info = trans->fs_info;
1985	struct btrfs_delayed_ref_root *delayed_refs;
1986	struct btrfs_delayed_ref_head *locked_ref = NULL;
1987	ktime_t start = ktime_get();
1988	int ret;
1989	unsigned long count = 0;
1990	unsigned long actual_count = 0;
1991
1992	delayed_refs = &trans->transaction->delayed_refs;
1993	do {
1994		if (!locked_ref) {
1995			locked_ref = btrfs_obtain_ref_head(trans);
1996			if (IS_ERR_OR_NULL(locked_ref)) {
1997				if (PTR_ERR(locked_ref) == -EAGAIN) {
1998					continue;
1999				} else {
2000					break;
2001				}
2002			}
2003			count++;
2004		}
2005		/*
2006		 * We need to try and merge add/drops of the same ref since we
2007		 * can run into issues with relocate dropping the implicit ref
2008		 * and then it being added back again before the drop can
2009		 * finish.  If we merged anything we need to re-loop so we can
2010		 * get a good ref.
2011		 * Or we can get node references of the same type that weren't
2012		 * merged when created due to bumps in the tree mod seq, and
2013		 * we need to merge them to prevent adding an inline extent
2014		 * backref before dropping it (triggering a BUG_ON at
2015		 * insert_inline_extent_backref()).
2016		 */
2017		spin_lock(&locked_ref->lock);
2018		btrfs_merge_delayed_refs(trans, delayed_refs, locked_ref);
2019
2020		ret = btrfs_run_delayed_refs_for_head(trans, locked_ref,
2021						      &actual_count);
2022		if (ret < 0 && ret != -EAGAIN) {
2023			/*
2024			 * Error, btrfs_run_delayed_refs_for_head already
2025			 * unlocked everything so just bail out
2026			 */
2027			return ret;
2028		} else if (!ret) {
2029			/*
2030			 * Success, perform the usual cleanup of a processed
2031			 * head
2032			 */
2033			ret = cleanup_ref_head(trans, locked_ref);
2034			if (ret > 0 ) {
2035				/* We dropped our lock, we need to loop. */
2036				ret = 0;
2037				continue;
2038			} else if (ret) {
2039				return ret;
2040			}
2041		}
2042
2043		/*
2044		 * Either success case or btrfs_run_delayed_refs_for_head
2045		 * returned -EAGAIN, meaning we need to select another head
2046		 */
2047
2048		locked_ref = NULL;
2049		cond_resched();
2050	} while ((nr != -1 && count < nr) || locked_ref);
2051
2052	/*
2053	 * We don't want to include ref heads since we can have empty ref heads
2054	 * and those will drastically skew our runtime down since we just do
2055	 * accounting, no actual extent tree updates.
2056	 */
2057	if (actual_count > 0) {
2058		u64 runtime = ktime_to_ns(ktime_sub(ktime_get(), start));
2059		u64 avg;
2060
2061		/*
2062		 * We weigh the current average higher than our current runtime
2063		 * to avoid large swings in the average.
2064		 */
2065		spin_lock(&delayed_refs->lock);
2066		avg = fs_info->avg_delayed_ref_runtime * 3 + runtime;
2067		fs_info->avg_delayed_ref_runtime = avg >> 2;	/* div by 4 */
2068		spin_unlock(&delayed_refs->lock);
2069	}
2070	return 0;
2071}
2072
2073#ifdef SCRAMBLE_DELAYED_REFS
2074/*
2075 * Normally delayed refs get processed in ascending bytenr order. This
2076 * correlates in most cases to the order added. To expose dependencies on this
2077 * order, we start to process the tree in the middle instead of the beginning
2078 */
2079static u64 find_middle(struct rb_root *root)
2080{
2081	struct rb_node *n = root->rb_node;
2082	struct btrfs_delayed_ref_node *entry;
2083	int alt = 1;
2084	u64 middle;
2085	u64 first = 0, last = 0;
2086
2087	n = rb_first(root);
2088	if (n) {
2089		entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2090		first = entry->bytenr;
2091	}
2092	n = rb_last(root);
2093	if (n) {
2094		entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2095		last = entry->bytenr;
2096	}
2097	n = root->rb_node;
2098
2099	while (n) {
2100		entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2101		WARN_ON(!entry->in_tree);
2102
2103		middle = entry->bytenr;
2104
2105		if (alt)
2106			n = n->rb_left;
2107		else
2108			n = n->rb_right;
2109
2110		alt = 1 - alt;
2111	}
2112	return middle;
2113}
2114#endif
2115
2116static inline u64 heads_to_leaves(struct btrfs_fs_info *fs_info, u64 heads)
2117{
2118	u64 num_bytes;
2119
2120	num_bytes = heads * (sizeof(struct btrfs_extent_item) +
2121			     sizeof(struct btrfs_extent_inline_ref));
2122	if (!btrfs_fs_incompat(fs_info, SKINNY_METADATA))
2123		num_bytes += heads * sizeof(struct btrfs_tree_block_info);
2124
2125	/*
2126	 * We don't ever fill up leaves all the way so multiply by 2 just to be
2127	 * closer to what we're really going to want to use.
2128	 */
2129	return div_u64(num_bytes, BTRFS_LEAF_DATA_SIZE(fs_info));
2130}
2131
2132/*
2133 * Takes the number of bytes to be csumm'ed and figures out how many leaves it
2134 * would require to store the csums for that many bytes.
2135 */
2136u64 btrfs_csum_bytes_to_leaves(struct btrfs_fs_info *fs_info, u64 csum_bytes)
2137{
2138	u64 csum_size;
2139	u64 num_csums_per_leaf;
2140	u64 num_csums;
2141
2142	csum_size = BTRFS_MAX_ITEM_SIZE(fs_info);
2143	num_csums_per_leaf = div64_u64(csum_size,
2144			(u64)btrfs_super_csum_size(fs_info->super_copy));
2145	num_csums = div64_u64(csum_bytes, fs_info->sectorsize);
2146	num_csums += num_csums_per_leaf - 1;
2147	num_csums = div64_u64(num_csums, num_csums_per_leaf);
2148	return num_csums;
2149}
2150
2151/*
2152 * this starts processing the delayed reference count updates and
2153 * extent insertions we have queued up so far.  count can be
2154 * 0, which means to process everything in the tree at the start
2155 * of the run (but not newly added entries), or it can be some target
2156 * number you'd like to process.
2157 *
2158 * Returns 0 on success or if called with an aborted transaction
2159 * Returns <0 on error and aborts the transaction
2160 */
2161int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
2162			   unsigned long count)
2163{
2164	struct btrfs_fs_info *fs_info = trans->fs_info;
2165	struct rb_node *node;
2166	struct btrfs_delayed_ref_root *delayed_refs;
2167	struct btrfs_delayed_ref_head *head;
2168	int ret;
2169	int run_all = count == (unsigned long)-1;
2170
2171	/* We'll clean this up in btrfs_cleanup_transaction */
2172	if (trans->aborted)
2173		return 0;
2174
2175	if (test_bit(BTRFS_FS_CREATING_FREE_SPACE_TREE, &fs_info->flags))
2176		return 0;
2177
2178	delayed_refs = &trans->transaction->delayed_refs;
2179	if (count == 0)
2180		count = atomic_read(&delayed_refs->num_entries) * 2;
2181
2182again:
2183#ifdef SCRAMBLE_DELAYED_REFS
2184	delayed_refs->run_delayed_start = find_middle(&delayed_refs->root);
2185#endif
2186	ret = __btrfs_run_delayed_refs(trans, count);
2187	if (ret < 0) {
2188		btrfs_abort_transaction(trans, ret);
2189		return ret;
2190	}
2191
2192	if (run_all) {
2193		btrfs_create_pending_block_groups(trans);
2194
2195		spin_lock(&delayed_refs->lock);
2196		node = rb_first_cached(&delayed_refs->href_root);
2197		if (!node) {
2198			spin_unlock(&delayed_refs->lock);
2199			goto out;
2200		}
2201		head = rb_entry(node, struct btrfs_delayed_ref_head,
2202				href_node);
2203		refcount_inc(&head->refs);
2204		spin_unlock(&delayed_refs->lock);
2205
2206		/* Mutex was contended, block until it's released and retry. */
2207		mutex_lock(&head->mutex);
2208		mutex_unlock(&head->mutex);
2209
2210		btrfs_put_delayed_ref_head(head);
2211		cond_resched();
2212		goto again;
2213	}
2214out:
2215	return 0;
2216}
2217
2218int btrfs_set_disk_extent_flags(struct btrfs_trans_handle *trans,
2219				u64 bytenr, u64 num_bytes, u64 flags,
2220				int level, int is_data)
2221{
2222	struct btrfs_delayed_extent_op *extent_op;
2223	int ret;
2224
2225	extent_op = btrfs_alloc_delayed_extent_op();
2226	if (!extent_op)
2227		return -ENOMEM;
2228
2229	extent_op->flags_to_set = flags;
2230	extent_op->update_flags = true;
2231	extent_op->update_key = false;
2232	extent_op->is_data = is_data ? true : false;
2233	extent_op->level = level;
2234
2235	ret = btrfs_add_delayed_extent_op(trans, bytenr, num_bytes, extent_op);
2236	if (ret)
2237		btrfs_free_delayed_extent_op(extent_op);
2238	return ret;
2239}
2240
2241static noinline int check_delayed_ref(struct btrfs_root *root,
2242				      struct btrfs_path *path,
2243				      u64 objectid, u64 offset, u64 bytenr)
2244{
2245	struct btrfs_delayed_ref_head *head;
2246	struct btrfs_delayed_ref_node *ref;
2247	struct btrfs_delayed_data_ref *data_ref;
2248	struct btrfs_delayed_ref_root *delayed_refs;
2249	struct btrfs_transaction *cur_trans;
2250	struct rb_node *node;
2251	int ret = 0;
2252
2253	spin_lock(&root->fs_info->trans_lock);
2254	cur_trans = root->fs_info->running_transaction;
2255	if (cur_trans)
2256		refcount_inc(&cur_trans->use_count);
2257	spin_unlock(&root->fs_info->trans_lock);
2258	if (!cur_trans)
2259		return 0;
2260
2261	delayed_refs = &cur_trans->delayed_refs;
2262	spin_lock(&delayed_refs->lock);
2263	head = btrfs_find_delayed_ref_head(delayed_refs, bytenr);
2264	if (!head) {
2265		spin_unlock(&delayed_refs->lock);
2266		btrfs_put_transaction(cur_trans);
2267		return 0;
2268	}
2269
2270	if (!mutex_trylock(&head->mutex)) {
 
 
 
 
 
 
2271		refcount_inc(&head->refs);
2272		spin_unlock(&delayed_refs->lock);
2273
2274		btrfs_release_path(path);
2275
2276		/*
2277		 * Mutex was contended, block until it's released and let
2278		 * caller try again
2279		 */
2280		mutex_lock(&head->mutex);
2281		mutex_unlock(&head->mutex);
2282		btrfs_put_delayed_ref_head(head);
2283		btrfs_put_transaction(cur_trans);
2284		return -EAGAIN;
2285	}
2286	spin_unlock(&delayed_refs->lock);
2287
2288	spin_lock(&head->lock);
2289	/*
2290	 * XXX: We should replace this with a proper search function in the
2291	 * future.
2292	 */
2293	for (node = rb_first_cached(&head->ref_tree); node;
2294	     node = rb_next(node)) {
2295		ref = rb_entry(node, struct btrfs_delayed_ref_node, ref_node);
2296		/* If it's a shared ref we know a cross reference exists */
2297		if (ref->type != BTRFS_EXTENT_DATA_REF_KEY) {
2298			ret = 1;
2299			break;
2300		}
2301
2302		data_ref = btrfs_delayed_node_to_data_ref(ref);
2303
2304		/*
2305		 * If our ref doesn't match the one we're currently looking at
2306		 * then we have a cross reference.
2307		 */
2308		if (data_ref->root != root->root_key.objectid ||
2309		    data_ref->objectid != objectid ||
2310		    data_ref->offset != offset) {
2311			ret = 1;
2312			break;
2313		}
2314	}
2315	spin_unlock(&head->lock);
2316	mutex_unlock(&head->mutex);
2317	btrfs_put_transaction(cur_trans);
2318	return ret;
2319}
2320
2321static noinline int check_committed_ref(struct btrfs_root *root,
2322					struct btrfs_path *path,
2323					u64 objectid, u64 offset, u64 bytenr)
 
2324{
2325	struct btrfs_fs_info *fs_info = root->fs_info;
2326	struct btrfs_root *extent_root = fs_info->extent_root;
2327	struct extent_buffer *leaf;
2328	struct btrfs_extent_data_ref *ref;
2329	struct btrfs_extent_inline_ref *iref;
2330	struct btrfs_extent_item *ei;
2331	struct btrfs_key key;
2332	u32 item_size;
2333	int type;
2334	int ret;
2335
2336	key.objectid = bytenr;
2337	key.offset = (u64)-1;
2338	key.type = BTRFS_EXTENT_ITEM_KEY;
2339
2340	ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
2341	if (ret < 0)
2342		goto out;
2343	BUG_ON(ret == 0); /* Corruption */
2344
2345	ret = -ENOENT;
2346	if (path->slots[0] == 0)
2347		goto out;
2348
2349	path->slots[0]--;
2350	leaf = path->nodes[0];
2351	btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2352
2353	if (key.objectid != bytenr || key.type != BTRFS_EXTENT_ITEM_KEY)
2354		goto out;
2355
2356	ret = 1;
2357	item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2358	ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2359
2360	/* If extent item has more than 1 inline ref then it's shared */
2361	if (item_size != sizeof(*ei) +
2362	    btrfs_extent_inline_ref_size(BTRFS_EXTENT_DATA_REF_KEY))
2363		goto out;
2364
2365	/* If extent created before last snapshot => it's definitely shared */
2366	if (btrfs_extent_generation(leaf, ei) <=
2367	    btrfs_root_last_snapshot(&root->root_item))
 
 
 
 
2368		goto out;
2369
2370	iref = (struct btrfs_extent_inline_ref *)(ei + 1);
2371
2372	/* If this extent has SHARED_DATA_REF then it's shared */
2373	type = btrfs_get_extent_inline_ref_type(leaf, iref, BTRFS_REF_TYPE_DATA);
2374	if (type != BTRFS_EXTENT_DATA_REF_KEY)
2375		goto out;
2376
2377	ref = (struct btrfs_extent_data_ref *)(&iref->offset);
2378	if (btrfs_extent_refs(leaf, ei) !=
2379	    btrfs_extent_data_ref_count(leaf, ref) ||
2380	    btrfs_extent_data_ref_root(leaf, ref) !=
2381	    root->root_key.objectid ||
2382	    btrfs_extent_data_ref_objectid(leaf, ref) != objectid ||
2383	    btrfs_extent_data_ref_offset(leaf, ref) != offset)
2384		goto out;
2385
2386	ret = 0;
2387out:
2388	return ret;
2389}
2390
2391int btrfs_cross_ref_exist(struct btrfs_root *root, u64 objectid, u64 offset,
2392			  u64 bytenr)
2393{
2394	struct btrfs_path *path;
2395	int ret;
2396
2397	path = btrfs_alloc_path();
2398	if (!path)
2399		return -ENOMEM;
2400
2401	do {
2402		ret = check_committed_ref(root, path, objectid,
2403					  offset, bytenr);
2404		if (ret && ret != -ENOENT)
2405			goto out;
2406
2407		ret = check_delayed_ref(root, path, objectid, offset, bytenr);
2408	} while (ret == -EAGAIN);
2409
2410out:
2411	btrfs_free_path(path);
2412	if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
2413		WARN_ON(ret > 0);
2414	return ret;
2415}
2416
2417static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
2418			   struct btrfs_root *root,
2419			   struct extent_buffer *buf,
2420			   int full_backref, int inc)
2421{
2422	struct btrfs_fs_info *fs_info = root->fs_info;
2423	u64 bytenr;
2424	u64 num_bytes;
2425	u64 parent;
2426	u64 ref_root;
2427	u32 nritems;
2428	struct btrfs_key key;
2429	struct btrfs_file_extent_item *fi;
2430	struct btrfs_ref generic_ref = { 0 };
2431	bool for_reloc = btrfs_header_flag(buf, BTRFS_HEADER_FLAG_RELOC);
2432	int i;
2433	int action;
2434	int level;
2435	int ret = 0;
2436
2437	if (btrfs_is_testing(fs_info))
2438		return 0;
2439
2440	ref_root = btrfs_header_owner(buf);
2441	nritems = btrfs_header_nritems(buf);
2442	level = btrfs_header_level(buf);
2443
2444	if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state) && level == 0)
2445		return 0;
2446
2447	if (full_backref)
2448		parent = buf->start;
2449	else
2450		parent = 0;
2451	if (inc)
2452		action = BTRFS_ADD_DELAYED_REF;
2453	else
2454		action = BTRFS_DROP_DELAYED_REF;
2455
2456	for (i = 0; i < nritems; i++) {
2457		if (level == 0) {
2458			btrfs_item_key_to_cpu(buf, &key, i);
2459			if (key.type != BTRFS_EXTENT_DATA_KEY)
2460				continue;
2461			fi = btrfs_item_ptr(buf, i,
2462					    struct btrfs_file_extent_item);
2463			if (btrfs_file_extent_type(buf, fi) ==
2464			    BTRFS_FILE_EXTENT_INLINE)
2465				continue;
2466			bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
2467			if (bytenr == 0)
2468				continue;
2469
2470			num_bytes = btrfs_file_extent_disk_num_bytes(buf, fi);
2471			key.offset -= btrfs_file_extent_offset(buf, fi);
2472			btrfs_init_generic_ref(&generic_ref, action, bytenr,
2473					       num_bytes, parent);
2474			generic_ref.real_root = root->root_key.objectid;
2475			btrfs_init_data_ref(&generic_ref, ref_root, key.objectid,
2476					    key.offset);
2477			generic_ref.skip_qgroup = for_reloc;
2478			if (inc)
2479				ret = btrfs_inc_extent_ref(trans, &generic_ref);
2480			else
2481				ret = btrfs_free_extent(trans, &generic_ref);
2482			if (ret)
2483				goto fail;
2484		} else {
2485			bytenr = btrfs_node_blockptr(buf, i);
2486			num_bytes = fs_info->nodesize;
2487			btrfs_init_generic_ref(&generic_ref, action, bytenr,
2488					       num_bytes, parent);
2489			generic_ref.real_root = root->root_key.objectid;
2490			btrfs_init_tree_ref(&generic_ref, level - 1, ref_root);
2491			generic_ref.skip_qgroup = for_reloc;
2492			if (inc)
2493				ret = btrfs_inc_extent_ref(trans, &generic_ref);
2494			else
2495				ret = btrfs_free_extent(trans, &generic_ref);
2496			if (ret)
2497				goto fail;
2498		}
2499	}
2500	return 0;
2501fail:
2502	return ret;
2503}
2504
2505int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2506		  struct extent_buffer *buf, int full_backref)
2507{
2508	return __btrfs_mod_ref(trans, root, buf, full_backref, 1);
2509}
2510
2511int btrfs_dec_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2512		  struct extent_buffer *buf, int full_backref)
2513{
2514	return __btrfs_mod_ref(trans, root, buf, full_backref, 0);
2515}
2516
2517int btrfs_extent_readonly(struct btrfs_fs_info *fs_info, u64 bytenr)
2518{
2519	struct btrfs_block_group_cache *block_group;
2520	int readonly = 0;
2521
2522	block_group = btrfs_lookup_block_group(fs_info, bytenr);
2523	if (!block_group || block_group->ro)
2524		readonly = 1;
2525	if (block_group)
2526		btrfs_put_block_group(block_group);
2527	return readonly;
2528}
2529
2530static u64 get_alloc_profile_by_root(struct btrfs_root *root, int data)
2531{
2532	struct btrfs_fs_info *fs_info = root->fs_info;
2533	u64 flags;
2534	u64 ret;
2535
2536	if (data)
2537		flags = BTRFS_BLOCK_GROUP_DATA;
2538	else if (root == fs_info->chunk_root)
2539		flags = BTRFS_BLOCK_GROUP_SYSTEM;
2540	else
2541		flags = BTRFS_BLOCK_GROUP_METADATA;
2542
2543	ret = btrfs_get_alloc_profile(fs_info, flags);
2544	return ret;
2545}
2546
2547static u64 first_logical_byte(struct btrfs_fs_info *fs_info, u64 search_start)
2548{
2549	struct btrfs_block_group_cache *cache;
2550	u64 bytenr;
2551
2552	spin_lock(&fs_info->block_group_cache_lock);
2553	bytenr = fs_info->first_logical_byte;
2554	spin_unlock(&fs_info->block_group_cache_lock);
2555
2556	if (bytenr < (u64)-1)
2557		return bytenr;
2558
2559	cache = btrfs_lookup_first_block_group(fs_info, search_start);
2560	if (!cache)
2561		return 0;
 
 
2562
2563	bytenr = cache->key.objectid;
2564	btrfs_put_block_group(cache);
 
 
2565
2566	return bytenr;
2567}
2568
2569static int pin_down_extent(struct btrfs_block_group_cache *cache,
 
2570			   u64 bytenr, u64 num_bytes, int reserved)
2571{
2572	struct btrfs_fs_info *fs_info = cache->fs_info;
2573
2574	spin_lock(&cache->space_info->lock);
2575	spin_lock(&cache->lock);
2576	cache->pinned += num_bytes;
2577	btrfs_space_info_update_bytes_pinned(fs_info, cache->space_info,
2578					     num_bytes);
2579	if (reserved) {
2580		cache->reserved -= num_bytes;
2581		cache->space_info->bytes_reserved -= num_bytes;
2582	}
2583	spin_unlock(&cache->lock);
2584	spin_unlock(&cache->space_info->lock);
2585
2586	percpu_counter_add_batch(&cache->space_info->total_bytes_pinned,
2587		    num_bytes, BTRFS_TOTAL_BYTES_PINNED_BATCH);
2588	set_extent_dirty(fs_info->pinned_extents, bytenr,
2589			 bytenr + num_bytes - 1, GFP_NOFS | __GFP_NOFAIL);
2590	return 0;
2591}
2592
2593/*
2594 * this function must be called within transaction
2595 */
2596int btrfs_pin_extent(struct btrfs_fs_info *fs_info,
2597		     u64 bytenr, u64 num_bytes, int reserved)
2598{
2599	struct btrfs_block_group_cache *cache;
2600
2601	cache = btrfs_lookup_block_group(fs_info, bytenr);
2602	BUG_ON(!cache); /* Logic error */
2603
2604	pin_down_extent(cache, bytenr, num_bytes, reserved);
2605
2606	btrfs_put_block_group(cache);
2607	return 0;
2608}
2609
2610/*
2611 * this function must be called within transaction
2612 */
2613int btrfs_pin_extent_for_log_replay(struct btrfs_fs_info *fs_info,
2614				    u64 bytenr, u64 num_bytes)
2615{
2616	struct btrfs_block_group_cache *cache;
2617	int ret;
2618
2619	cache = btrfs_lookup_block_group(fs_info, bytenr);
2620	if (!cache)
2621		return -EINVAL;
2622
2623	/*
2624	 * pull in the free space cache (if any) so that our pin
2625	 * removes the free space from the cache.  We have load_only set
2626	 * to one because the slow code to read in the free extents does check
2627	 * the pinned extents.
2628	 */
2629	btrfs_cache_block_group(cache, 1);
 
 
2630
2631	pin_down_extent(cache, bytenr, num_bytes, 0);
2632
2633	/* remove us from the free space cache (if we're there at all) */
2634	ret = btrfs_remove_free_space(cache, bytenr, num_bytes);
 
2635	btrfs_put_block_group(cache);
2636	return ret;
2637}
2638
2639static int __exclude_logged_extent(struct btrfs_fs_info *fs_info,
2640				   u64 start, u64 num_bytes)
2641{
2642	int ret;
2643	struct btrfs_block_group_cache *block_group;
2644	struct btrfs_caching_control *caching_ctl;
2645
2646	block_group = btrfs_lookup_block_group(fs_info, start);
2647	if (!block_group)
2648		return -EINVAL;
2649
2650	btrfs_cache_block_group(block_group, 0);
2651	caching_ctl = btrfs_get_caching_control(block_group);
2652
2653	if (!caching_ctl) {
2654		/* Logic error */
2655		BUG_ON(!btrfs_block_group_cache_done(block_group));
2656		ret = btrfs_remove_free_space(block_group, start, num_bytes);
2657	} else {
2658		mutex_lock(&caching_ctl->mutex);
2659
2660		if (start >= caching_ctl->progress) {
2661			ret = btrfs_add_excluded_extent(fs_info, start,
2662							num_bytes);
2663		} else if (start + num_bytes <= caching_ctl->progress) {
2664			ret = btrfs_remove_free_space(block_group,
2665						      start, num_bytes);
2666		} else {
2667			num_bytes = caching_ctl->progress - start;
2668			ret = btrfs_remove_free_space(block_group,
2669						      start, num_bytes);
2670			if (ret)
2671				goto out_lock;
2672
2673			num_bytes = (start + num_bytes) -
2674				caching_ctl->progress;
2675			start = caching_ctl->progress;
2676			ret = btrfs_add_excluded_extent(fs_info, start,
2677							num_bytes);
2678		}
2679out_lock:
2680		mutex_unlock(&caching_ctl->mutex);
2681		btrfs_put_caching_control(caching_ctl);
2682	}
2683	btrfs_put_block_group(block_group);
2684	return ret;
2685}
2686
2687int btrfs_exclude_logged_extents(struct extent_buffer *eb)
2688{
2689	struct btrfs_fs_info *fs_info = eb->fs_info;
2690	struct btrfs_file_extent_item *item;
2691	struct btrfs_key key;
2692	int found_type;
2693	int i;
2694	int ret = 0;
2695
2696	if (!btrfs_fs_incompat(fs_info, MIXED_GROUPS))
2697		return 0;
2698
2699	for (i = 0; i < btrfs_header_nritems(eb); i++) {
2700		btrfs_item_key_to_cpu(eb, &key, i);
2701		if (key.type != BTRFS_EXTENT_DATA_KEY)
2702			continue;
2703		item = btrfs_item_ptr(eb, i, struct btrfs_file_extent_item);
2704		found_type = btrfs_file_extent_type(eb, item);
2705		if (found_type == BTRFS_FILE_EXTENT_INLINE)
2706			continue;
2707		if (btrfs_file_extent_disk_bytenr(eb, item) == 0)
2708			continue;
2709		key.objectid = btrfs_file_extent_disk_bytenr(eb, item);
2710		key.offset = btrfs_file_extent_disk_num_bytes(eb, item);
2711		ret = __exclude_logged_extent(fs_info, key.objectid, key.offset);
2712		if (ret)
2713			break;
2714	}
2715
2716	return ret;
2717}
2718
2719static void
2720btrfs_inc_block_group_reservations(struct btrfs_block_group_cache *bg)
2721{
2722	atomic_inc(&bg->reservations);
2723}
2724
2725void btrfs_prepare_extent_commit(struct btrfs_fs_info *fs_info)
2726{
2727	struct btrfs_caching_control *next;
2728	struct btrfs_caching_control *caching_ctl;
2729	struct btrfs_block_group_cache *cache;
2730
2731	down_write(&fs_info->commit_root_sem);
2732
2733	list_for_each_entry_safe(caching_ctl, next,
2734				 &fs_info->caching_block_groups, list) {
2735		cache = caching_ctl->block_group;
2736		if (btrfs_block_group_cache_done(cache)) {
2737			cache->last_byte_to_unpin = (u64)-1;
2738			list_del_init(&caching_ctl->list);
2739			btrfs_put_caching_control(caching_ctl);
2740		} else {
2741			cache->last_byte_to_unpin = caching_ctl->progress;
2742		}
2743	}
2744
2745	if (fs_info->pinned_extents == &fs_info->freed_extents[0])
2746		fs_info->pinned_extents = &fs_info->freed_extents[1];
2747	else
2748		fs_info->pinned_extents = &fs_info->freed_extents[0];
2749
2750	up_write(&fs_info->commit_root_sem);
2751
2752	btrfs_update_global_block_rsv(fs_info);
2753}
2754
2755/*
2756 * Returns the free cluster for the given space info and sets empty_cluster to
2757 * what it should be based on the mount options.
2758 */
2759static struct btrfs_free_cluster *
2760fetch_cluster_info(struct btrfs_fs_info *fs_info,
2761		   struct btrfs_space_info *space_info, u64 *empty_cluster)
2762{
2763	struct btrfs_free_cluster *ret = NULL;
2764
2765	*empty_cluster = 0;
2766	if (btrfs_mixed_space_info(space_info))
2767		return ret;
2768
2769	if (space_info->flags & BTRFS_BLOCK_GROUP_METADATA) {
2770		ret = &fs_info->meta_alloc_cluster;
2771		if (btrfs_test_opt(fs_info, SSD))
2772			*empty_cluster = SZ_2M;
2773		else
2774			*empty_cluster = SZ_64K;
2775	} else if ((space_info->flags & BTRFS_BLOCK_GROUP_DATA) &&
2776		   btrfs_test_opt(fs_info, SSD_SPREAD)) {
2777		*empty_cluster = SZ_2M;
2778		ret = &fs_info->data_alloc_cluster;
2779	}
2780
2781	return ret;
2782}
2783
2784static int unpin_extent_range(struct btrfs_fs_info *fs_info,
2785			      u64 start, u64 end,
2786			      const bool return_free_space)
2787{
2788	struct btrfs_block_group_cache *cache = NULL;
2789	struct btrfs_space_info *space_info;
2790	struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
2791	struct btrfs_free_cluster *cluster = NULL;
2792	u64 len;
2793	u64 total_unpinned = 0;
2794	u64 empty_cluster = 0;
2795	bool readonly;
2796
2797	while (start <= end) {
2798		readonly = false;
2799		if (!cache ||
2800		    start >= cache->key.objectid + cache->key.offset) {
2801			if (cache)
2802				btrfs_put_block_group(cache);
2803			total_unpinned = 0;
2804			cache = btrfs_lookup_block_group(fs_info, start);
2805			BUG_ON(!cache); /* Logic error */
2806
2807			cluster = fetch_cluster_info(fs_info,
2808						     cache->space_info,
2809						     &empty_cluster);
2810			empty_cluster <<= 1;
2811		}
2812
2813		len = cache->key.objectid + cache->key.offset - start;
2814		len = min(len, end + 1 - start);
2815
2816		if (start < cache->last_byte_to_unpin) {
2817			len = min(len, cache->last_byte_to_unpin - start);
2818			if (return_free_space)
2819				btrfs_add_free_space(cache, start, len);
2820		}
2821
2822		start += len;
2823		total_unpinned += len;
2824		space_info = cache->space_info;
2825
2826		/*
2827		 * If this space cluster has been marked as fragmented and we've
2828		 * unpinned enough in this block group to potentially allow a
2829		 * cluster to be created inside of it go ahead and clear the
2830		 * fragmented check.
2831		 */
2832		if (cluster && cluster->fragmented &&
2833		    total_unpinned > empty_cluster) {
2834			spin_lock(&cluster->lock);
2835			cluster->fragmented = 0;
2836			spin_unlock(&cluster->lock);
2837		}
2838
2839		spin_lock(&space_info->lock);
2840		spin_lock(&cache->lock);
2841		cache->pinned -= len;
2842		btrfs_space_info_update_bytes_pinned(fs_info, space_info, -len);
2843		space_info->max_extent_size = 0;
2844		percpu_counter_add_batch(&space_info->total_bytes_pinned,
2845			    -len, BTRFS_TOTAL_BYTES_PINNED_BATCH);
2846		if (cache->ro) {
2847			space_info->bytes_readonly += len;
2848			readonly = true;
 
 
 
 
2849		}
2850		spin_unlock(&cache->lock);
2851		if (!readonly && return_free_space &&
2852		    global_rsv->space_info == space_info) {
2853			u64 to_add = len;
2854
2855			spin_lock(&global_rsv->lock);
2856			if (!global_rsv->full) {
2857				to_add = min(len, global_rsv->size -
2858					     global_rsv->reserved);
 
2859				global_rsv->reserved += to_add;
2860				btrfs_space_info_update_bytes_may_use(fs_info,
2861						space_info, to_add);
2862				if (global_rsv->reserved >= global_rsv->size)
2863					global_rsv->full = 1;
2864				len -= to_add;
2865			}
2866			spin_unlock(&global_rsv->lock);
2867			/* Add to any tickets we may have */
2868			if (len)
2869				btrfs_try_granting_tickets(fs_info,
2870							   space_info);
2871		}
 
 
 
2872		spin_unlock(&space_info->lock);
2873	}
2874
2875	if (cache)
2876		btrfs_put_block_group(cache);
2877	return 0;
2878}
2879
2880int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans)
2881{
2882	struct btrfs_fs_info *fs_info = trans->fs_info;
2883	struct btrfs_block_group_cache *block_group, *tmp;
2884	struct list_head *deleted_bgs;
2885	struct extent_io_tree *unpin;
2886	u64 start;
2887	u64 end;
2888	int ret;
2889
2890	if (fs_info->pinned_extents == &fs_info->freed_extents[0])
2891		unpin = &fs_info->freed_extents[1];
2892	else
2893		unpin = &fs_info->freed_extents[0];
2894
2895	while (!trans->aborted) {
2896		struct extent_state *cached_state = NULL;
2897
2898		mutex_lock(&fs_info->unused_bg_unpin_mutex);
2899		ret = find_first_extent_bit(unpin, 0, &start, &end,
2900					    EXTENT_DIRTY, &cached_state);
2901		if (ret) {
2902			mutex_unlock(&fs_info->unused_bg_unpin_mutex);
2903			break;
2904		}
2905
2906		if (btrfs_test_opt(fs_info, DISCARD))
2907			ret = btrfs_discard_extent(fs_info, start,
2908						   end + 1 - start, NULL);
2909
2910		clear_extent_dirty(unpin, start, end, &cached_state);
2911		unpin_extent_range(fs_info, start, end, true);
2912		mutex_unlock(&fs_info->unused_bg_unpin_mutex);
2913		free_extent_state(cached_state);
2914		cond_resched();
2915	}
2916
 
 
 
 
 
2917	/*
2918	 * Transaction is finished.  We don't need the lock anymore.  We
2919	 * do need to clean up the block groups in case of a transaction
2920	 * abort.
2921	 */
2922	deleted_bgs = &trans->transaction->deleted_bgs;
2923	list_for_each_entry_safe(block_group, tmp, deleted_bgs, bg_list) {
2924		u64 trimmed = 0;
2925
2926		ret = -EROFS;
2927		if (!trans->aborted)
2928			ret = btrfs_discard_extent(fs_info,
2929						   block_group->key.objectid,
2930						   block_group->key.offset,
2931						   &trimmed);
2932
2933		list_del_init(&block_group->bg_list);
2934		btrfs_put_block_group_trimming(block_group);
2935		btrfs_put_block_group(block_group);
2936
2937		if (ret) {
2938			const char *errstr = btrfs_decode_error(ret);
2939			btrfs_warn(fs_info,
2940			   "discard failed while removing blockgroup: errno=%d %s",
2941				   ret, errstr);
2942		}
2943	}
2944
2945	return 0;
2946}
2947
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2948static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
2949			       struct btrfs_delayed_ref_node *node, u64 parent,
2950			       u64 root_objectid, u64 owner_objectid,
2951			       u64 owner_offset, int refs_to_drop,
2952			       struct btrfs_delayed_extent_op *extent_op)
2953{
2954	struct btrfs_fs_info *info = trans->fs_info;
2955	struct btrfs_key key;
2956	struct btrfs_path *path;
2957	struct btrfs_root *extent_root = info->extent_root;
2958	struct extent_buffer *leaf;
2959	struct btrfs_extent_item *ei;
2960	struct btrfs_extent_inline_ref *iref;
2961	int ret;
2962	int is_data;
2963	int extent_slot = 0;
2964	int found_extent = 0;
2965	int num_to_del = 1;
2966	u32 item_size;
2967	u64 refs;
2968	u64 bytenr = node->bytenr;
2969	u64 num_bytes = node->num_bytes;
2970	int last_ref = 0;
2971	bool skinny_metadata = btrfs_fs_incompat(info, SKINNY_METADATA);
2972
 
 
 
2973	path = btrfs_alloc_path();
2974	if (!path)
2975		return -ENOMEM;
2976
2977	path->reada = READA_FORWARD;
2978	path->leave_spinning = 1;
2979
2980	is_data = owner_objectid >= BTRFS_FIRST_FREE_OBJECTID;
2981	BUG_ON(!is_data && refs_to_drop != 1);
 
 
 
 
 
 
 
 
2982
2983	if (is_data)
2984		skinny_metadata = false;
2985
2986	ret = lookup_extent_backref(trans, path, &iref, bytenr, num_bytes,
2987				    parent, root_objectid, owner_objectid,
2988				    owner_offset);
2989	if (ret == 0) {
 
 
 
 
 
 
 
2990		extent_slot = path->slots[0];
2991		while (extent_slot >= 0) {
2992			btrfs_item_key_to_cpu(path->nodes[0], &key,
2993					      extent_slot);
2994			if (key.objectid != bytenr)
2995				break;
2996			if (key.type == BTRFS_EXTENT_ITEM_KEY &&
2997			    key.offset == num_bytes) {
2998				found_extent = 1;
2999				break;
3000			}
3001			if (key.type == BTRFS_METADATA_ITEM_KEY &&
3002			    key.offset == owner_objectid) {
3003				found_extent = 1;
3004				break;
3005			}
 
 
3006			if (path->slots[0] - extent_slot > 5)
3007				break;
3008			extent_slot--;
3009		}
3010
3011		if (!found_extent) {
3012			BUG_ON(iref);
3013			ret = remove_extent_backref(trans, path, NULL,
3014						    refs_to_drop,
3015						    is_data, &last_ref);
 
 
 
 
 
3016			if (ret) {
3017				btrfs_abort_transaction(trans, ret);
3018				goto out;
3019			}
3020			btrfs_release_path(path);
3021			path->leave_spinning = 1;
3022
 
3023			key.objectid = bytenr;
3024			key.type = BTRFS_EXTENT_ITEM_KEY;
3025			key.offset = num_bytes;
3026
3027			if (!is_data && skinny_metadata) {
3028				key.type = BTRFS_METADATA_ITEM_KEY;
3029				key.offset = owner_objectid;
3030			}
3031
3032			ret = btrfs_search_slot(trans, extent_root,
3033						&key, path, -1, 1);
3034			if (ret > 0 && skinny_metadata && path->slots[0]) {
3035				/*
3036				 * Couldn't find our skinny metadata item,
3037				 * see if we have ye olde extent item.
3038				 */
3039				path->slots[0]--;
3040				btrfs_item_key_to_cpu(path->nodes[0], &key,
3041						      path->slots[0]);
3042				if (key.objectid == bytenr &&
3043				    key.type == BTRFS_EXTENT_ITEM_KEY &&
3044				    key.offset == num_bytes)
3045					ret = 0;
3046			}
3047
3048			if (ret > 0 && skinny_metadata) {
3049				skinny_metadata = false;
3050				key.objectid = bytenr;
3051				key.type = BTRFS_EXTENT_ITEM_KEY;
3052				key.offset = num_bytes;
3053				btrfs_release_path(path);
3054				ret = btrfs_search_slot(trans, extent_root,
3055							&key, path, -1, 1);
3056			}
3057
3058			if (ret) {
3059				btrfs_err(info,
3060					  "umm, got %d back from search, was looking for %llu",
3061					  ret, bytenr);
3062				if (ret > 0)
3063					btrfs_print_leaf(path->nodes[0]);
3064			}
3065			if (ret < 0) {
3066				btrfs_abort_transaction(trans, ret);
3067				goto out;
3068			}
3069			extent_slot = path->slots[0];
3070		}
3071	} else if (WARN_ON(ret == -ENOENT)) {
3072		btrfs_print_leaf(path->nodes[0]);
3073		btrfs_err(info,
3074			"unable to find ref byte nr %llu parent %llu root %llu  owner %llu offset %llu",
3075			bytenr, parent, root_objectid, owner_objectid,
3076			owner_offset);
3077		btrfs_abort_transaction(trans, ret);
3078		goto out;
3079	} else {
3080		btrfs_abort_transaction(trans, ret);
3081		goto out;
3082	}
3083
3084	leaf = path->nodes[0];
3085	item_size = btrfs_item_size_nr(leaf, extent_slot);
3086	if (unlikely(item_size < sizeof(*ei))) {
3087		ret = -EINVAL;
3088		btrfs_print_v0_err(info);
3089		btrfs_abort_transaction(trans, ret);
3090		goto out;
3091	}
3092	ei = btrfs_item_ptr(leaf, extent_slot,
3093			    struct btrfs_extent_item);
3094	if (owner_objectid < BTRFS_FIRST_FREE_OBJECTID &&
3095	    key.type == BTRFS_EXTENT_ITEM_KEY) {
3096		struct btrfs_tree_block_info *bi;
3097		BUG_ON(item_size < sizeof(*ei) + sizeof(*bi));
 
 
 
 
 
 
 
 
3098		bi = (struct btrfs_tree_block_info *)(ei + 1);
3099		WARN_ON(owner_objectid != btrfs_tree_block_level(leaf, bi));
3100	}
3101
3102	refs = btrfs_extent_refs(leaf, ei);
3103	if (refs < refs_to_drop) {
3104		btrfs_err(info,
3105			  "trying to drop %d refs but we only have %Lu for bytenr %Lu",
3106			  refs_to_drop, refs, bytenr);
3107		ret = -EINVAL;
3108		btrfs_abort_transaction(trans, ret);
3109		goto out;
3110	}
3111	refs -= refs_to_drop;
3112
3113	if (refs > 0) {
3114		if (extent_op)
3115			__run_delayed_extent_op(extent_op, leaf, ei);
3116		/*
3117		 * In the case of inline back ref, reference count will
3118		 * be updated by remove_extent_backref
3119		 */
3120		if (iref) {
3121			BUG_ON(!found_extent);
 
 
 
 
 
3122		} else {
3123			btrfs_set_extent_refs(leaf, ei, refs);
3124			btrfs_mark_buffer_dirty(leaf);
3125		}
3126		if (found_extent) {
3127			ret = remove_extent_backref(trans, path, iref,
3128						    refs_to_drop, is_data,
3129						    &last_ref);
3130			if (ret) {
3131				btrfs_abort_transaction(trans, ret);
3132				goto out;
3133			}
3134		}
3135	} else {
 
3136		if (found_extent) {
3137			BUG_ON(is_data && refs_to_drop !=
3138			       extent_data_ref_count(path, iref));
 
 
 
 
 
 
 
3139			if (iref) {
3140				BUG_ON(path->slots[0] != extent_slot);
 
 
 
 
 
 
 
3141			} else {
3142				BUG_ON(path->slots[0] != extent_slot + 1);
 
 
 
 
 
 
 
 
 
 
 
3143				path->slots[0] = extent_slot;
3144				num_to_del = 2;
3145			}
3146		}
3147
3148		last_ref = 1;
3149		ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
3150				      num_to_del);
3151		if (ret) {
3152			btrfs_abort_transaction(trans, ret);
3153			goto out;
3154		}
3155		btrfs_release_path(path);
3156
3157		if (is_data) {
3158			ret = btrfs_del_csums(trans, info, bytenr, num_bytes);
3159			if (ret) {
3160				btrfs_abort_transaction(trans, ret);
3161				goto out;
3162			}
3163		}
3164
3165		ret = add_to_free_space_tree(trans, bytenr, num_bytes);
3166		if (ret) {
3167			btrfs_abort_transaction(trans, ret);
3168			goto out;
3169		}
3170
3171		ret = btrfs_update_block_group(trans, bytenr, num_bytes, 0);
3172		if (ret) {
3173			btrfs_abort_transaction(trans, ret);
3174			goto out;
3175		}
3176	}
3177	btrfs_release_path(path);
3178
3179out:
3180	btrfs_free_path(path);
3181	return ret;
 
 
 
 
 
 
 
 
 
 
 
 
 
3182}
3183
3184/*
3185 * when we free an block, it is possible (and likely) that we free the last
3186 * delayed ref for that extent as well.  This searches the delayed ref tree for
3187 * a given extent, and if there are no other delayed refs to be processed, it
3188 * removes it from the tree.
3189 */
3190static noinline int check_ref_cleanup(struct btrfs_trans_handle *trans,
3191				      u64 bytenr)
3192{
3193	struct btrfs_delayed_ref_head *head;
3194	struct btrfs_delayed_ref_root *delayed_refs;
3195	int ret = 0;
3196
3197	delayed_refs = &trans->transaction->delayed_refs;
3198	spin_lock(&delayed_refs->lock);
3199	head = btrfs_find_delayed_ref_head(delayed_refs, bytenr);
3200	if (!head)
3201		goto out_delayed_unlock;
3202
3203	spin_lock(&head->lock);
3204	if (!RB_EMPTY_ROOT(&head->ref_tree.rb_root))
3205		goto out;
3206
3207	if (cleanup_extent_op(head) != NULL)
3208		goto out;
3209
3210	/*
3211	 * waiting for the lock here would deadlock.  If someone else has it
3212	 * locked they are already in the process of dropping it anyway
3213	 */
3214	if (!mutex_trylock(&head->mutex))
3215		goto out;
3216
3217	btrfs_delete_ref_head(delayed_refs, head);
3218	head->processing = 0;
3219
3220	spin_unlock(&head->lock);
3221	spin_unlock(&delayed_refs->lock);
3222
3223	BUG_ON(head->extent_op);
3224	if (head->must_insert_reserved)
3225		ret = 1;
3226
3227	btrfs_cleanup_ref_head_accounting(trans->fs_info, delayed_refs, head);
3228	mutex_unlock(&head->mutex);
3229	btrfs_put_delayed_ref_head(head);
3230	return ret;
3231out:
3232	spin_unlock(&head->lock);
3233
3234out_delayed_unlock:
3235	spin_unlock(&delayed_refs->lock);
3236	return 0;
3237}
3238
3239void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
3240			   struct btrfs_root *root,
3241			   struct extent_buffer *buf,
3242			   u64 parent, int last_ref)
3243{
3244	struct btrfs_fs_info *fs_info = root->fs_info;
3245	struct btrfs_ref generic_ref = { 0 };
3246	int pin = 1;
3247	int ret;
3248
3249	btrfs_init_generic_ref(&generic_ref, BTRFS_DROP_DELAYED_REF,
3250			       buf->start, buf->len, parent);
3251	btrfs_init_tree_ref(&generic_ref, btrfs_header_level(buf),
3252			    root->root_key.objectid);
3253
3254	if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
3255		int old_ref_mod, new_ref_mod;
3256
 
3257		btrfs_ref_tree_mod(fs_info, &generic_ref);
3258		ret = btrfs_add_delayed_tree_ref(trans, &generic_ref, NULL,
3259						 &old_ref_mod, &new_ref_mod);
3260		BUG_ON(ret); /* -ENOMEM */
3261		pin = old_ref_mod >= 0 && new_ref_mod < 0;
3262	}
3263
3264	if (last_ref && btrfs_header_generation(buf) == trans->transid) {
3265		struct btrfs_block_group_cache *cache;
 
3266
3267		if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
3268			ret = check_ref_cleanup(trans, buf->start);
3269			if (!ret)
 
3270				goto out;
 
3271		}
3272
3273		pin = 0;
3274		cache = btrfs_lookup_block_group(fs_info, buf->start);
3275
3276		if (btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
3277			pin_down_extent(cache, buf->start, buf->len, 1);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3278			btrfs_put_block_group(cache);
3279			goto out;
3280		}
3281
3282		WARN_ON(test_bit(EXTENT_BUFFER_DIRTY, &buf->bflags));
3283
3284		btrfs_add_free_space(cache, buf->start, buf->len);
3285		btrfs_free_reserved_bytes(cache, buf->len, 0);
3286		btrfs_put_block_group(cache);
3287		trace_btrfs_reserved_extent_free(fs_info, buf->start, buf->len);
3288	}
3289out:
3290	if (pin)
3291		add_pinned_bytes(fs_info, &generic_ref);
3292
3293	if (last_ref) {
3294		/*
3295		 * Deleting the buffer, clear the corrupt flag since it doesn't
3296		 * matter anymore.
3297		 */
3298		clear_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags);
3299	}
3300}
3301
3302/* Can return -ENOMEM */
3303int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_ref *ref)
3304{
3305	struct btrfs_fs_info *fs_info = trans->fs_info;
3306	int old_ref_mod, new_ref_mod;
3307	int ret;
3308
3309	if (btrfs_is_testing(fs_info))
3310		return 0;
3311
3312	/*
3313	 * tree log blocks never actually go into the extent allocation
3314	 * tree, just update pinning info and exit early.
3315	 */
3316	if ((ref->type == BTRFS_REF_METADATA &&
3317	     ref->tree_ref.root == BTRFS_TREE_LOG_OBJECTID) ||
3318	    (ref->type == BTRFS_REF_DATA &&
3319	     ref->data_ref.ref_root == BTRFS_TREE_LOG_OBJECTID)) {
3320		/* unlocks the pinned mutex */
3321		btrfs_pin_extent(fs_info, ref->bytenr, ref->len, 1);
3322		old_ref_mod = new_ref_mod = 0;
3323		ret = 0;
3324	} else if (ref->type == BTRFS_REF_METADATA) {
3325		ret = btrfs_add_delayed_tree_ref(trans, ref, NULL,
3326						 &old_ref_mod, &new_ref_mod);
3327	} else {
3328		ret = btrfs_add_delayed_data_ref(trans, ref, 0,
3329						 &old_ref_mod, &new_ref_mod);
3330	}
3331
3332	if (!((ref->type == BTRFS_REF_METADATA &&
3333	       ref->tree_ref.root == BTRFS_TREE_LOG_OBJECTID) ||
3334	      (ref->type == BTRFS_REF_DATA &&
3335	       ref->data_ref.ref_root == BTRFS_TREE_LOG_OBJECTID)))
3336		btrfs_ref_tree_mod(fs_info, ref);
3337
3338	if (ret == 0 && old_ref_mod >= 0 && new_ref_mod < 0)
3339		add_pinned_bytes(fs_info, ref);
3340
3341	return ret;
3342}
3343
3344enum btrfs_loop_type {
3345	LOOP_CACHING_NOWAIT,
3346	LOOP_CACHING_WAIT,
3347	LOOP_ALLOC_CHUNK,
3348	LOOP_NO_EMPTY_SIZE,
3349};
3350
3351static inline void
3352btrfs_lock_block_group(struct btrfs_block_group_cache *cache,
3353		       int delalloc)
3354{
3355	if (delalloc)
3356		down_read(&cache->data_rwsem);
3357}
3358
3359static inline void
3360btrfs_grab_block_group(struct btrfs_block_group_cache *cache,
3361		       int delalloc)
3362{
3363	btrfs_get_block_group(cache);
3364	if (delalloc)
3365		down_read(&cache->data_rwsem);
3366}
3367
3368static struct btrfs_block_group_cache *
3369btrfs_lock_cluster(struct btrfs_block_group_cache *block_group,
3370		   struct btrfs_free_cluster *cluster,
3371		   int delalloc)
 
3372{
3373	struct btrfs_block_group_cache *used_bg = NULL;
3374
3375	spin_lock(&cluster->refill_lock);
3376	while (1) {
3377		used_bg = cluster->block_group;
3378		if (!used_bg)
3379			return NULL;
3380
3381		if (used_bg == block_group)
3382			return used_bg;
3383
3384		btrfs_get_block_group(used_bg);
3385
3386		if (!delalloc)
3387			return used_bg;
3388
3389		if (down_read_trylock(&used_bg->data_rwsem))
3390			return used_bg;
3391
3392		spin_unlock(&cluster->refill_lock);
3393
3394		/* We should only have one-level nested. */
3395		down_read_nested(&used_bg->data_rwsem, SINGLE_DEPTH_NESTING);
3396
3397		spin_lock(&cluster->refill_lock);
3398		if (used_bg == cluster->block_group)
3399			return used_bg;
3400
3401		up_read(&used_bg->data_rwsem);
3402		btrfs_put_block_group(used_bg);
3403	}
3404}
3405
3406static inline void
3407btrfs_release_block_group(struct btrfs_block_group_cache *cache,
3408			 int delalloc)
3409{
3410	if (delalloc)
3411		up_read(&cache->data_rwsem);
3412	btrfs_put_block_group(cache);
3413}
3414
 
 
 
 
 
3415/*
3416 * Structure used internally for find_free_extent() function.  Wraps needed
3417 * parameters.
3418 */
3419struct find_free_extent_ctl {
3420	/* Basic allocation info */
3421	u64 ram_bytes;
3422	u64 num_bytes;
 
3423	u64 empty_size;
3424	u64 flags;
3425	int delalloc;
3426
3427	/* Where to start the search inside the bg */
3428	u64 search_start;
3429
3430	/* For clustered allocation */
3431	u64 empty_cluster;
 
 
3432
3433	bool have_caching_bg;
3434	bool orig_have_caching_bg;
3435
 
 
 
 
 
 
3436	/* RAID index, converted from flags */
3437	int index;
3438
3439	/*
3440	 * Current loop number, check find_free_extent_update_loop() for details
3441	 */
3442	int loop;
3443
3444	/*
3445	 * Whether we're refilling a cluster, if true we need to re-search
3446	 * current block group but don't try to refill the cluster again.
3447	 */
3448	bool retry_clustered;
3449
3450	/*
3451	 * Whether we're updating free space cache, if true we need to re-search
3452	 * current block group but don't try updating free space cache again.
3453	 */
3454	bool retry_unclustered;
3455
3456	/* If current block group is cached */
3457	int cached;
3458
3459	/* Max contiguous hole found */
3460	u64 max_extent_size;
3461
3462	/* Total free space from free space cache, not always contiguous */
3463	u64 total_free_space;
3464
3465	/* Found result */
3466	u64 found_offset;
 
 
 
 
 
 
3467};
3468
3469
3470/*
3471 * Helper function for find_free_extent().
3472 *
3473 * Return -ENOENT to inform caller that we need fallback to unclustered mode.
3474 * Return -EAGAIN to inform caller that we need to re-search this block group
3475 * Return >0 to inform caller that we find nothing
3476 * Return 0 means we have found a location and set ffe_ctl->found_offset.
3477 */
3478static int find_free_extent_clustered(struct btrfs_block_group_cache *bg,
3479		struct btrfs_free_cluster *last_ptr,
3480		struct find_free_extent_ctl *ffe_ctl,
3481		struct btrfs_block_group_cache **cluster_bg_ret)
3482{
3483	struct btrfs_block_group_cache *cluster_bg;
 
3484	u64 aligned_cluster;
3485	u64 offset;
3486	int ret;
3487
3488	cluster_bg = btrfs_lock_cluster(bg, last_ptr, ffe_ctl->delalloc);
3489	if (!cluster_bg)
3490		goto refill_cluster;
3491	if (cluster_bg != bg && (cluster_bg->ro ||
3492	    !block_group_bits(cluster_bg, ffe_ctl->flags)))
3493		goto release_cluster;
3494
3495	offset = btrfs_alloc_from_cluster(cluster_bg, last_ptr,
3496			ffe_ctl->num_bytes, cluster_bg->key.objectid,
3497			&ffe_ctl->max_extent_size);
3498	if (offset) {
3499		/* We have a block, we're done */
3500		spin_unlock(&last_ptr->refill_lock);
3501		trace_btrfs_reserve_extent_cluster(cluster_bg,
3502				ffe_ctl->search_start, ffe_ctl->num_bytes);
3503		*cluster_bg_ret = cluster_bg;
3504		ffe_ctl->found_offset = offset;
3505		return 0;
3506	}
3507	WARN_ON(last_ptr->block_group != cluster_bg);
3508
3509release_cluster:
3510	/*
3511	 * If we are on LOOP_NO_EMPTY_SIZE, we can't set up a new clusters, so
3512	 * lets just skip it and let the allocator find whatever block it can
3513	 * find. If we reach this point, we will have tried the cluster
3514	 * allocator plenty of times and not have found anything, so we are
3515	 * likely way too fragmented for the clustering stuff to find anything.
3516	 *
3517	 * However, if the cluster is taken from the current block group,
3518	 * release the cluster first, so that we stand a better chance of
3519	 * succeeding in the unclustered allocation.
3520	 */
3521	if (ffe_ctl->loop >= LOOP_NO_EMPTY_SIZE && cluster_bg != bg) {
3522		spin_unlock(&last_ptr->refill_lock);
3523		btrfs_release_block_group(cluster_bg, ffe_ctl->delalloc);
3524		return -ENOENT;
3525	}
3526
3527	/* This cluster didn't work out, free it and start over */
3528	btrfs_return_cluster_to_free_space(NULL, last_ptr);
3529
3530	if (cluster_bg != bg)
3531		btrfs_release_block_group(cluster_bg, ffe_ctl->delalloc);
3532
3533refill_cluster:
3534	if (ffe_ctl->loop >= LOOP_NO_EMPTY_SIZE) {
3535		spin_unlock(&last_ptr->refill_lock);
3536		return -ENOENT;
3537	}
3538
3539	aligned_cluster = max_t(u64,
3540			ffe_ctl->empty_cluster + ffe_ctl->empty_size,
3541			bg->full_stripe_len);
3542	ret = btrfs_find_space_cluster(bg, last_ptr, ffe_ctl->search_start,
3543			ffe_ctl->num_bytes, aligned_cluster);
3544	if (ret == 0) {
3545		/* Now pull our allocation out of this cluster */
3546		offset = btrfs_alloc_from_cluster(bg, last_ptr,
3547				ffe_ctl->num_bytes, ffe_ctl->search_start,
3548				&ffe_ctl->max_extent_size);
3549		if (offset) {
3550			/* We found one, proceed */
3551			spin_unlock(&last_ptr->refill_lock);
3552			trace_btrfs_reserve_extent_cluster(bg,
3553					ffe_ctl->search_start,
3554					ffe_ctl->num_bytes);
3555			ffe_ctl->found_offset = offset;
3556			return 0;
3557		}
3558	} else if (!ffe_ctl->cached && ffe_ctl->loop > LOOP_CACHING_NOWAIT &&
3559		   !ffe_ctl->retry_clustered) {
3560		spin_unlock(&last_ptr->refill_lock);
3561
3562		ffe_ctl->retry_clustered = true;
3563		btrfs_wait_block_group_cache_progress(bg, ffe_ctl->num_bytes +
3564				ffe_ctl->empty_cluster + ffe_ctl->empty_size);
3565		return -EAGAIN;
3566	}
3567	/*
3568	 * At this point we either didn't find a cluster or we weren't able to
3569	 * allocate a block from our cluster.  Free the cluster we've been
3570	 * trying to use, and go to the next block group.
3571	 */
3572	btrfs_return_cluster_to_free_space(NULL, last_ptr);
3573	spin_unlock(&last_ptr->refill_lock);
3574	return 1;
3575}
3576
3577/*
3578 * Return >0 to inform caller that we find nothing
3579 * Return 0 when we found an free extent and set ffe_ctrl->found_offset
3580 * Return -EAGAIN to inform caller that we need to re-search this block group
3581 */
3582static int find_free_extent_unclustered(struct btrfs_block_group_cache *bg,
3583		struct btrfs_free_cluster *last_ptr,
3584		struct find_free_extent_ctl *ffe_ctl)
3585{
 
3586	u64 offset;
3587
3588	/*
3589	 * We are doing an unclustered allocation, set the fragmented flag so
3590	 * we don't bother trying to setup a cluster again until we get more
3591	 * space.
3592	 */
3593	if (unlikely(last_ptr)) {
3594		spin_lock(&last_ptr->lock);
3595		last_ptr->fragmented = 1;
3596		spin_unlock(&last_ptr->lock);
3597	}
3598	if (ffe_ctl->cached) {
3599		struct btrfs_free_space_ctl *free_space_ctl;
3600
3601		free_space_ctl = bg->free_space_ctl;
3602		spin_lock(&free_space_ctl->tree_lock);
3603		if (free_space_ctl->free_space <
3604		    ffe_ctl->num_bytes + ffe_ctl->empty_cluster +
3605		    ffe_ctl->empty_size) {
3606			ffe_ctl->total_free_space = max_t(u64,
3607					ffe_ctl->total_free_space,
3608					free_space_ctl->free_space);
3609			spin_unlock(&free_space_ctl->tree_lock);
3610			return 1;
3611		}
3612		spin_unlock(&free_space_ctl->tree_lock);
3613	}
3614
3615	offset = btrfs_find_space_for_alloc(bg, ffe_ctl->search_start,
3616			ffe_ctl->num_bytes, ffe_ctl->empty_size,
3617			&ffe_ctl->max_extent_size);
3618
3619	/*
3620	 * If we didn't find a chunk, and we haven't failed on this block group
3621	 * before, and this block group is in the middle of caching and we are
3622	 * ok with waiting, then go ahead and wait for progress to be made, and
3623	 * set @retry_unclustered to true.
3624	 *
3625	 * If @retry_unclustered is true then we've already waited on this
3626	 * block group once and should move on to the next block group.
3627	 */
3628	if (!offset && !ffe_ctl->retry_unclustered && !ffe_ctl->cached &&
3629	    ffe_ctl->loop > LOOP_CACHING_NOWAIT) {
3630		btrfs_wait_block_group_cache_progress(bg, ffe_ctl->num_bytes +
3631						      ffe_ctl->empty_size);
3632		ffe_ctl->retry_unclustered = true;
3633		return -EAGAIN;
3634	} else if (!offset) {
3635		return 1;
3636	}
3637	ffe_ctl->found_offset = offset;
3638	return 0;
3639}
3640
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3641/*
3642 * Return >0 means caller needs to re-search for free extent
3643 * Return 0 means we have the needed free extent.
3644 * Return <0 means we failed to locate any free extent.
3645 */
3646static int find_free_extent_update_loop(struct btrfs_fs_info *fs_info,
3647					struct btrfs_free_cluster *last_ptr,
3648					struct btrfs_key *ins,
3649					struct find_free_extent_ctl *ffe_ctl,
3650					int full_search, bool use_cluster)
3651{
3652	struct btrfs_root *root = fs_info->extent_root;
3653	int ret;
3654
3655	if ((ffe_ctl->loop == LOOP_CACHING_NOWAIT) &&
3656	    ffe_ctl->have_caching_bg && !ffe_ctl->orig_have_caching_bg)
3657		ffe_ctl->orig_have_caching_bg = true;
3658
3659	if (!ins->objectid && ffe_ctl->loop >= LOOP_CACHING_WAIT &&
3660	    ffe_ctl->have_caching_bg)
3661		return 1;
3662
3663	if (!ins->objectid && ++(ffe_ctl->index) < BTRFS_NR_RAID_TYPES)
3664		return 1;
3665
3666	if (ins->objectid) {
3667		if (!use_cluster && last_ptr) {
3668			spin_lock(&last_ptr->lock);
3669			last_ptr->window_start = ins->objectid;
3670			spin_unlock(&last_ptr->lock);
3671		}
3672		return 0;
3673	}
3674
 
 
 
 
 
 
 
3675	/*
3676	 * LOOP_CACHING_NOWAIT, search partially cached block groups, kicking
3677	 *			caching kthreads as we move along
3678	 * LOOP_CACHING_WAIT, search everything, and wait if our bg is caching
3679	 * LOOP_ALLOC_CHUNK, force a chunk allocation and try again
3680	 * LOOP_NO_EMPTY_SIZE, set empty_size and empty_cluster to 0 and try
3681	 *		       again
3682	 */
3683	if (ffe_ctl->loop < LOOP_NO_EMPTY_SIZE) {
3684		ffe_ctl->index = 0;
3685		if (ffe_ctl->loop == LOOP_CACHING_NOWAIT) {
3686			/*
3687			 * We want to skip the LOOP_CACHING_WAIT step if we
3688			 * don't have any uncached bgs and we've already done a
3689			 * full search through.
3690			 */
3691			if (ffe_ctl->orig_have_caching_bg || !full_search)
3692				ffe_ctl->loop = LOOP_CACHING_WAIT;
3693			else
3694				ffe_ctl->loop = LOOP_ALLOC_CHUNK;
3695		} else {
3696			ffe_ctl->loop++;
3697		}
3698
3699		if (ffe_ctl->loop == LOOP_ALLOC_CHUNK) {
3700			struct btrfs_trans_handle *trans;
3701			int exist = 0;
3702
 
 
 
 
 
3703			trans = current->journal_info;
3704			if (trans)
3705				exist = 1;
3706			else
3707				trans = btrfs_join_transaction(root);
3708
3709			if (IS_ERR(trans)) {
3710				ret = PTR_ERR(trans);
3711				return ret;
3712			}
3713
3714			ret = btrfs_chunk_alloc(trans, ffe_ctl->flags,
3715						CHUNK_ALLOC_FORCE);
3716
3717			/*
3718			 * If we can't allocate a new chunk we've already looped
3719			 * through at least once, move on to the NO_EMPTY_SIZE
3720			 * case.
3721			 */
3722			if (ret == -ENOSPC)
3723				ffe_ctl->loop = LOOP_NO_EMPTY_SIZE;
3724
3725			/* Do not bail out on ENOSPC since we can do more. */
3726			if (ret < 0 && ret != -ENOSPC)
 
 
3727				btrfs_abort_transaction(trans, ret);
3728			else
3729				ret = 0;
3730			if (!exist)
3731				btrfs_end_transaction(trans);
3732			if (ret)
3733				return ret;
3734		}
3735
3736		if (ffe_ctl->loop == LOOP_NO_EMPTY_SIZE) {
 
 
 
3737			/*
3738			 * Don't loop again if we already have no empty_size and
3739			 * no empty_cluster.
3740			 */
3741			if (ffe_ctl->empty_size == 0 &&
3742			    ffe_ctl->empty_cluster == 0)
3743				return -ENOSPC;
3744			ffe_ctl->empty_size = 0;
3745			ffe_ctl->empty_cluster = 0;
3746		}
3747		return 1;
3748	}
3749	return -ENOSPC;
3750}
3751
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3752/*
3753 * walks the btree of allocated extents and find a hole of a given size.
3754 * The key ins is changed to record the hole:
3755 * ins->objectid == start position
3756 * ins->flags = BTRFS_EXTENT_ITEM_KEY
3757 * ins->offset == the size of the hole.
3758 * Any available blocks before search_start are skipped.
3759 *
3760 * If there is no suitable free space, we will record the max size of
3761 * the free space extent currently.
3762 *
3763 * The overall logic and call chain:
3764 *
3765 * find_free_extent()
3766 * |- Iterate through all block groups
3767 * |  |- Get a valid block group
3768 * |  |- Try to do clustered allocation in that block group
3769 * |  |- Try to do unclustered allocation in that block group
3770 * |  |- Check if the result is valid
3771 * |  |  |- If valid, then exit
3772 * |  |- Jump to next block group
3773 * |
3774 * |- Push harder to find free extents
3775 *    |- If not found, re-iterate all block groups
3776 */
3777static noinline int find_free_extent(struct btrfs_fs_info *fs_info,
3778				u64 ram_bytes, u64 num_bytes, u64 empty_size,
3779				u64 hint_byte, struct btrfs_key *ins,
3780				u64 flags, int delalloc)
3781{
 
3782	int ret = 0;
3783	struct btrfs_free_cluster *last_ptr = NULL;
3784	struct btrfs_block_group_cache *block_group = NULL;
3785	struct find_free_extent_ctl ffe_ctl = {0};
3786	struct btrfs_space_info *space_info;
3787	bool use_cluster = true;
3788	bool full_search = false;
3789
3790	WARN_ON(num_bytes < fs_info->sectorsize);
3791
3792	ffe_ctl.ram_bytes = ram_bytes;
3793	ffe_ctl.num_bytes = num_bytes;
3794	ffe_ctl.empty_size = empty_size;
3795	ffe_ctl.flags = flags;
3796	ffe_ctl.search_start = 0;
3797	ffe_ctl.retry_clustered = false;
3798	ffe_ctl.retry_unclustered = false;
3799	ffe_ctl.delalloc = delalloc;
3800	ffe_ctl.index = btrfs_bg_flags_to_raid_index(flags);
3801	ffe_ctl.have_caching_bg = false;
3802	ffe_ctl.orig_have_caching_bg = false;
3803	ffe_ctl.found_offset = 0;
 
 
 
 
 
 
 
 
3804
3805	ins->type = BTRFS_EXTENT_ITEM_KEY;
3806	ins->objectid = 0;
3807	ins->offset = 0;
3808
3809	trace_find_free_extent(fs_info, num_bytes, empty_size, flags);
 
3810
3811	space_info = btrfs_find_space_info(fs_info, flags);
3812	if (!space_info) {
3813		btrfs_err(fs_info, "No space info for %llu", flags);
3814		return -ENOSPC;
3815	}
3816
3817	/*
3818	 * If our free space is heavily fragmented we may not be able to make
3819	 * big contiguous allocations, so instead of doing the expensive search
3820	 * for free space, simply return ENOSPC with our max_extent_size so we
3821	 * can go ahead and search for a more manageable chunk.
3822	 *
3823	 * If our max_extent_size is large enough for our allocation simply
3824	 * disable clustering since we will likely not be able to find enough
3825	 * space to create a cluster and induce latency trying.
3826	 */
3827	if (unlikely(space_info->max_extent_size)) {
3828		spin_lock(&space_info->lock);
3829		if (space_info->max_extent_size &&
3830		    num_bytes > space_info->max_extent_size) {
3831			ins->offset = space_info->max_extent_size;
3832			spin_unlock(&space_info->lock);
3833			return -ENOSPC;
3834		} else if (space_info->max_extent_size) {
3835			use_cluster = false;
3836		}
3837		spin_unlock(&space_info->lock);
3838	}
3839
3840	last_ptr = fetch_cluster_info(fs_info, space_info,
3841				      &ffe_ctl.empty_cluster);
3842	if (last_ptr) {
3843		spin_lock(&last_ptr->lock);
3844		if (last_ptr->block_group)
3845			hint_byte = last_ptr->window_start;
3846		if (last_ptr->fragmented) {
3847			/*
3848			 * We still set window_start so we can keep track of the
3849			 * last place we found an allocation to try and save
3850			 * some time.
3851			 */
3852			hint_byte = last_ptr->window_start;
3853			use_cluster = false;
3854		}
3855		spin_unlock(&last_ptr->lock);
3856	}
3857
3858	ffe_ctl.search_start = max(ffe_ctl.search_start,
3859				   first_logical_byte(fs_info, 0));
3860	ffe_ctl.search_start = max(ffe_ctl.search_start, hint_byte);
3861	if (ffe_ctl.search_start == hint_byte) {
3862		block_group = btrfs_lookup_block_group(fs_info,
3863						       ffe_ctl.search_start);
3864		/*
3865		 * we don't want to use the block group if it doesn't match our
3866		 * allocation bits, or if its not cached.
3867		 *
3868		 * However if we are re-searching with an ideal block group
3869		 * picked out then we don't care that the block group is cached.
3870		 */
3871		if (block_group && block_group_bits(block_group, flags) &&
3872		    block_group->cached != BTRFS_CACHE_NO) {
3873			down_read(&space_info->groups_sem);
3874			if (list_empty(&block_group->list) ||
3875			    block_group->ro) {
3876				/*
3877				 * someone is removing this block group,
3878				 * we can't jump into the have_block_group
3879				 * target because our list pointers are not
3880				 * valid
3881				 */
3882				btrfs_put_block_group(block_group);
3883				up_read(&space_info->groups_sem);
3884			} else {
3885				ffe_ctl.index = btrfs_bg_flags_to_raid_index(
3886						block_group->flags);
3887				btrfs_lock_block_group(block_group, delalloc);
 
3888				goto have_block_group;
3889			}
3890		} else if (block_group) {
3891			btrfs_put_block_group(block_group);
3892		}
3893	}
3894search:
3895	ffe_ctl.have_caching_bg = false;
3896	if (ffe_ctl.index == btrfs_bg_flags_to_raid_index(flags) ||
3897	    ffe_ctl.index == 0)
3898		full_search = true;
3899	down_read(&space_info->groups_sem);
3900	list_for_each_entry(block_group,
3901			    &space_info->block_groups[ffe_ctl.index], list) {
 
 
3902		/* If the block group is read-only, we can skip it entirely. */
3903		if (unlikely(block_group->ro))
 
 
 
 
3904			continue;
 
3905
3906		btrfs_grab_block_group(block_group, delalloc);
3907		ffe_ctl.search_start = block_group->key.objectid;
3908
3909		/*
3910		 * this can happen if we end up cycling through all the
3911		 * raid types, but we want to make sure we only allocate
3912		 * for the proper type.
3913		 */
3914		if (!block_group_bits(block_group, flags)) {
3915			u64 extra = BTRFS_BLOCK_GROUP_DUP |
3916				BTRFS_BLOCK_GROUP_RAID1_MASK |
3917				BTRFS_BLOCK_GROUP_RAID56_MASK |
3918				BTRFS_BLOCK_GROUP_RAID10;
3919
3920			/*
3921			 * if they asked for extra copies and this block group
3922			 * doesn't provide them, bail.  This does allow us to
3923			 * fill raid0 from raid1.
3924			 */
3925			if ((flags & extra) && !(block_group->flags & extra))
3926				goto loop;
3927
3928			/*
3929			 * This block group has different flags than we want.
3930			 * It's possible that we have MIXED_GROUP flag but no
3931			 * block group is mixed.  Just skip such block group.
3932			 */
3933			btrfs_release_block_group(block_group, delalloc);
3934			continue;
3935		}
3936
3937have_block_group:
3938		ffe_ctl.cached = btrfs_block_group_cache_done(block_group);
3939		if (unlikely(!ffe_ctl.cached)) {
3940			ffe_ctl.have_caching_bg = true;
3941			ret = btrfs_cache_block_group(block_group, 0);
3942			BUG_ON(ret < 0);
 
 
 
 
 
 
 
 
 
 
 
 
 
3943			ret = 0;
3944		}
3945
3946		if (unlikely(block_group->cached == BTRFS_CACHE_ERROR))
3947			goto loop;
3948
3949		/*
3950		 * Ok we want to try and use the cluster allocator, so
3951		 * lets look there
3952		 */
3953		if (last_ptr && use_cluster) {
3954			struct btrfs_block_group_cache *cluster_bg = NULL;
3955
3956			ret = find_free_extent_clustered(block_group, last_ptr,
3957							 &ffe_ctl, &cluster_bg);
3958
3959			if (ret == 0) {
3960				if (cluster_bg && cluster_bg != block_group) {
3961					btrfs_release_block_group(block_group,
3962								  delalloc);
3963					block_group = cluster_bg;
3964				}
3965				goto checks;
3966			} else if (ret == -EAGAIN) {
3967				goto have_block_group;
3968			} else if (ret > 0) {
3969				goto loop;
3970			}
3971			/* ret == -ENOENT case falls through */
3972		}
3973
3974		ret = find_free_extent_unclustered(block_group, last_ptr,
3975						   &ffe_ctl);
3976		if (ret == -EAGAIN)
3977			goto have_block_group;
3978		else if (ret > 0)
3979			goto loop;
3980		/* ret == 0 case falls through */
3981checks:
3982		ffe_ctl.search_start = round_up(ffe_ctl.found_offset,
3983					     fs_info->stripesize);
 
3984
3985		/* move on to the next group */
3986		if (ffe_ctl.search_start + num_bytes >
3987		    block_group->key.objectid + block_group->key.offset) {
3988			btrfs_add_free_space(block_group, ffe_ctl.found_offset,
3989					     num_bytes);
 
3990			goto loop;
3991		}
3992
3993		if (ffe_ctl.found_offset < ffe_ctl.search_start)
3994			btrfs_add_free_space(block_group, ffe_ctl.found_offset,
3995				ffe_ctl.search_start - ffe_ctl.found_offset);
3996
3997		ret = btrfs_add_reserved_bytes(block_group, ram_bytes,
3998				num_bytes, delalloc);
 
 
3999		if (ret == -EAGAIN) {
4000			btrfs_add_free_space(block_group, ffe_ctl.found_offset,
4001					     num_bytes);
 
4002			goto loop;
4003		}
4004		btrfs_inc_block_group_reservations(block_group);
4005
4006		/* we are all good, lets return */
4007		ins->objectid = ffe_ctl.search_start;
4008		ins->offset = num_bytes;
4009
4010		trace_btrfs_reserve_extent(block_group, ffe_ctl.search_start,
4011					   num_bytes);
4012		btrfs_release_block_group(block_group, delalloc);
4013		break;
4014loop:
4015		ffe_ctl.retry_clustered = false;
4016		ffe_ctl.retry_unclustered = false;
4017		BUG_ON(btrfs_bg_flags_to_raid_index(block_group->flags) !=
4018		       ffe_ctl.index);
4019		btrfs_release_block_group(block_group, delalloc);
4020		cond_resched();
4021	}
4022	up_read(&space_info->groups_sem);
4023
4024	ret = find_free_extent_update_loop(fs_info, last_ptr, ins, &ffe_ctl,
4025					   full_search, use_cluster);
4026	if (ret > 0)
4027		goto search;
4028
4029	if (ret == -ENOSPC) {
4030		/*
4031		 * Use ffe_ctl->total_free_space as fallback if we can't find
4032		 * any contiguous hole.
4033		 */
4034		if (!ffe_ctl.max_extent_size)
4035			ffe_ctl.max_extent_size = ffe_ctl.total_free_space;
4036		spin_lock(&space_info->lock);
4037		space_info->max_extent_size = ffe_ctl.max_extent_size;
4038		spin_unlock(&space_info->lock);
4039		ins->offset = ffe_ctl.max_extent_size;
 
 
4040	}
4041	return ret;
4042}
4043
4044/*
4045 * btrfs_reserve_extent - entry point to the extent allocator. Tries to find a
4046 *			  hole that is at least as big as @num_bytes.
4047 *
4048 * @root           -	The root that will contain this extent
4049 *
4050 * @ram_bytes      -	The amount of space in ram that @num_bytes take. This
4051 *			is used for accounting purposes. This value differs
4052 *			from @num_bytes only in the case of compressed extents.
4053 *
4054 * @num_bytes      -	Number of bytes to allocate on-disk.
4055 *
4056 * @min_alloc_size -	Indicates the minimum amount of space that the
4057 *			allocator should try to satisfy. In some cases
4058 *			@num_bytes may be larger than what is required and if
4059 *			the filesystem is fragmented then allocation fails.
4060 *			However, the presence of @min_alloc_size gives a
4061 *			chance to try and satisfy the smaller allocation.
4062 *
4063 * @empty_size     -	A hint that you plan on doing more COW. This is the
4064 *			size in bytes the allocator should try to find free
4065 *			next to the block it returns.  This is just a hint and
4066 *			may be ignored by the allocator.
4067 *
4068 * @hint_byte      -	Hint to the allocator to start searching above the byte
4069 *			address passed. It might be ignored.
4070 *
4071 * @ins            -	This key is modified to record the found hole. It will
4072 *			have the following values:
4073 *			ins->objectid == start position
4074 *			ins->flags = BTRFS_EXTENT_ITEM_KEY
4075 *			ins->offset == the size of the hole.
4076 *
4077 * @is_data        -	Boolean flag indicating whether an extent is
4078 *			allocated for data (true) or metadata (false)
4079 *
4080 * @delalloc       -	Boolean flag indicating whether this allocation is for
4081 *			delalloc or not. If 'true' data_rwsem of block groups
4082 *			is going to be acquired.
4083 *
4084 *
4085 * Returns 0 when an allocation succeeded or < 0 when an error occurred. In
4086 * case -ENOSPC is returned then @ins->offset will contain the size of the
4087 * largest available hole the allocator managed to find.
4088 */
4089int btrfs_reserve_extent(struct btrfs_root *root, u64 ram_bytes,
4090			 u64 num_bytes, u64 min_alloc_size,
4091			 u64 empty_size, u64 hint_byte,
4092			 struct btrfs_key *ins, int is_data, int delalloc)
4093{
4094	struct btrfs_fs_info *fs_info = root->fs_info;
 
4095	bool final_tried = num_bytes == min_alloc_size;
4096	u64 flags;
4097	int ret;
 
 
4098
4099	flags = get_alloc_profile_by_root(root, is_data);
4100again:
4101	WARN_ON(num_bytes < fs_info->sectorsize);
4102	ret = find_free_extent(fs_info, ram_bytes, num_bytes, empty_size,
4103			       hint_byte, ins, flags, delalloc);
 
 
 
 
 
 
 
 
 
 
4104	if (!ret && !is_data) {
4105		btrfs_dec_block_group_reservations(fs_info, ins->objectid);
4106	} else if (ret == -ENOSPC) {
4107		if (!final_tried && ins->offset) {
4108			num_bytes = min(num_bytes >> 1, ins->offset);
4109			num_bytes = round_down(num_bytes,
4110					       fs_info->sectorsize);
4111			num_bytes = max(num_bytes, min_alloc_size);
4112			ram_bytes = num_bytes;
4113			if (num_bytes == min_alloc_size)
4114				final_tried = true;
4115			goto again;
4116		} else if (btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
4117			struct btrfs_space_info *sinfo;
4118
4119			sinfo = btrfs_find_space_info(fs_info, flags);
4120			btrfs_err(fs_info,
4121				  "allocation failed flags %llu, wanted %llu",
4122				  flags, num_bytes);
4123			if (sinfo)
4124				btrfs_dump_space_info(fs_info, sinfo,
4125						      num_bytes, 1);
4126		}
4127	}
4128
4129	return ret;
4130}
4131
4132static int __btrfs_free_reserved_extent(struct btrfs_fs_info *fs_info,
4133					u64 start, u64 len,
4134					int pin, int delalloc)
4135{
4136	struct btrfs_block_group_cache *cache;
4137	int ret = 0;
4138
4139	cache = btrfs_lookup_block_group(fs_info, start);
4140	if (!cache) {
4141		btrfs_err(fs_info, "Unable to find block group for %llu",
4142			  start);
4143		return -ENOSPC;
4144	}
4145
4146	if (pin)
4147		pin_down_extent(cache, start, len, 1);
4148	else {
4149		if (btrfs_test_opt(fs_info, DISCARD))
4150			ret = btrfs_discard_extent(fs_info, start, len, NULL);
4151		btrfs_add_free_space(cache, start, len);
4152		btrfs_free_reserved_bytes(cache, len, delalloc);
4153		trace_btrfs_reserved_extent_free(fs_info, start, len);
4154	}
4155
4156	btrfs_put_block_group(cache);
4157	return ret;
4158}
4159
4160int btrfs_free_reserved_extent(struct btrfs_fs_info *fs_info,
4161			       u64 start, u64 len, int delalloc)
4162{
4163	return __btrfs_free_reserved_extent(fs_info, start, len, 0, delalloc);
 
 
 
 
 
 
 
 
 
 
 
 
4164}
4165
4166int btrfs_free_and_pin_reserved_extent(struct btrfs_fs_info *fs_info,
4167				       u64 start, u64 len)
4168{
4169	return __btrfs_free_reserved_extent(fs_info, start, len, 1, 0);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4170}
4171
4172static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
4173				      u64 parent, u64 root_objectid,
4174				      u64 flags, u64 owner, u64 offset,
4175				      struct btrfs_key *ins, int ref_mod)
4176{
4177	struct btrfs_fs_info *fs_info = trans->fs_info;
 
4178	int ret;
4179	struct btrfs_extent_item *extent_item;
4180	struct btrfs_extent_inline_ref *iref;
4181	struct btrfs_path *path;
4182	struct extent_buffer *leaf;
4183	int type;
4184	u32 size;
4185
4186	if (parent > 0)
4187		type = BTRFS_SHARED_DATA_REF_KEY;
4188	else
4189		type = BTRFS_EXTENT_DATA_REF_KEY;
4190
4191	size = sizeof(*extent_item) + btrfs_extent_inline_ref_size(type);
4192
4193	path = btrfs_alloc_path();
4194	if (!path)
4195		return -ENOMEM;
4196
4197	path->leave_spinning = 1;
4198	ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
4199				      ins, size);
4200	if (ret) {
4201		btrfs_free_path(path);
4202		return ret;
4203	}
4204
4205	leaf = path->nodes[0];
4206	extent_item = btrfs_item_ptr(leaf, path->slots[0],
4207				     struct btrfs_extent_item);
4208	btrfs_set_extent_refs(leaf, extent_item, ref_mod);
4209	btrfs_set_extent_generation(leaf, extent_item, trans->transid);
4210	btrfs_set_extent_flags(leaf, extent_item,
4211			       flags | BTRFS_EXTENT_FLAG_DATA);
4212
4213	iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
4214	btrfs_set_extent_inline_ref_type(leaf, iref, type);
4215	if (parent > 0) {
4216		struct btrfs_shared_data_ref *ref;
4217		ref = (struct btrfs_shared_data_ref *)(iref + 1);
4218		btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
4219		btrfs_set_shared_data_ref_count(leaf, ref, ref_mod);
4220	} else {
4221		struct btrfs_extent_data_ref *ref;
4222		ref = (struct btrfs_extent_data_ref *)(&iref->offset);
4223		btrfs_set_extent_data_ref_root(leaf, ref, root_objectid);
4224		btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
4225		btrfs_set_extent_data_ref_offset(leaf, ref, offset);
4226		btrfs_set_extent_data_ref_count(leaf, ref, ref_mod);
4227	}
4228
4229	btrfs_mark_buffer_dirty(path->nodes[0]);
4230	btrfs_free_path(path);
4231
4232	ret = remove_from_free_space_tree(trans, ins->objectid, ins->offset);
4233	if (ret)
4234		return ret;
4235
4236	ret = btrfs_update_block_group(trans, ins->objectid, ins->offset, 1);
4237	if (ret) { /* -ENOENT, logic error */
4238		btrfs_err(fs_info, "update block group failed for %llu %llu",
4239			ins->objectid, ins->offset);
4240		BUG();
4241	}
4242	trace_btrfs_reserved_extent_alloc(fs_info, ins->objectid, ins->offset);
4243	return ret;
4244}
4245
4246static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
4247				     struct btrfs_delayed_ref_node *node,
4248				     struct btrfs_delayed_extent_op *extent_op)
4249{
4250	struct btrfs_fs_info *fs_info = trans->fs_info;
 
4251	int ret;
4252	struct btrfs_extent_item *extent_item;
4253	struct btrfs_key extent_key;
4254	struct btrfs_tree_block_info *block_info;
4255	struct btrfs_extent_inline_ref *iref;
4256	struct btrfs_path *path;
4257	struct extent_buffer *leaf;
4258	struct btrfs_delayed_tree_ref *ref;
4259	u32 size = sizeof(*extent_item) + sizeof(*iref);
4260	u64 num_bytes;
4261	u64 flags = extent_op->flags_to_set;
4262	bool skinny_metadata = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
4263
4264	ref = btrfs_delayed_node_to_tree_ref(node);
4265
4266	extent_key.objectid = node->bytenr;
4267	if (skinny_metadata) {
4268		extent_key.offset = ref->level;
4269		extent_key.type = BTRFS_METADATA_ITEM_KEY;
4270		num_bytes = fs_info->nodesize;
4271	} else {
4272		extent_key.offset = node->num_bytes;
4273		extent_key.type = BTRFS_EXTENT_ITEM_KEY;
4274		size += sizeof(*block_info);
4275		num_bytes = node->num_bytes;
4276	}
4277
4278	path = btrfs_alloc_path();
4279	if (!path)
4280		return -ENOMEM;
4281
4282	path->leave_spinning = 1;
4283	ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
4284				      &extent_key, size);
4285	if (ret) {
4286		btrfs_free_path(path);
4287		return ret;
4288	}
4289
4290	leaf = path->nodes[0];
4291	extent_item = btrfs_item_ptr(leaf, path->slots[0],
4292				     struct btrfs_extent_item);
4293	btrfs_set_extent_refs(leaf, extent_item, 1);
4294	btrfs_set_extent_generation(leaf, extent_item, trans->transid);
4295	btrfs_set_extent_flags(leaf, extent_item,
4296			       flags | BTRFS_EXTENT_FLAG_TREE_BLOCK);
4297
4298	if (skinny_metadata) {
4299		iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
4300	} else {
4301		block_info = (struct btrfs_tree_block_info *)(extent_item + 1);
4302		btrfs_set_tree_block_key(leaf, block_info, &extent_op->key);
4303		btrfs_set_tree_block_level(leaf, block_info, ref->level);
4304		iref = (struct btrfs_extent_inline_ref *)(block_info + 1);
4305	}
4306
4307	if (node->type == BTRFS_SHARED_BLOCK_REF_KEY) {
4308		BUG_ON(!(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF));
4309		btrfs_set_extent_inline_ref_type(leaf, iref,
4310						 BTRFS_SHARED_BLOCK_REF_KEY);
4311		btrfs_set_extent_inline_ref_offset(leaf, iref, ref->parent);
4312	} else {
4313		btrfs_set_extent_inline_ref_type(leaf, iref,
4314						 BTRFS_TREE_BLOCK_REF_KEY);
4315		btrfs_set_extent_inline_ref_offset(leaf, iref, ref->root);
4316	}
4317
4318	btrfs_mark_buffer_dirty(leaf);
4319	btrfs_free_path(path);
4320
4321	ret = remove_from_free_space_tree(trans, extent_key.objectid,
4322					  num_bytes);
4323	if (ret)
4324		return ret;
4325
4326	ret = btrfs_update_block_group(trans, extent_key.objectid,
4327				       fs_info->nodesize, 1);
4328	if (ret) { /* -ENOENT, logic error */
4329		btrfs_err(fs_info, "update block group failed for %llu %llu",
4330			extent_key.objectid, extent_key.offset);
4331		BUG();
4332	}
4333
4334	trace_btrfs_reserved_extent_alloc(fs_info, extent_key.objectid,
4335					  fs_info->nodesize);
4336	return ret;
4337}
4338
4339int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
4340				     struct btrfs_root *root, u64 owner,
4341				     u64 offset, u64 ram_bytes,
4342				     struct btrfs_key *ins)
4343{
4344	struct btrfs_ref generic_ref = { 0 };
4345	int ret;
4346
4347	BUG_ON(root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID);
4348
4349	btrfs_init_generic_ref(&generic_ref, BTRFS_ADD_DELAYED_EXTENT,
4350			       ins->objectid, ins->offset, 0);
4351	btrfs_init_data_ref(&generic_ref, root->root_key.objectid, owner, offset);
 
4352	btrfs_ref_tree_mod(root->fs_info, &generic_ref);
4353	ret = btrfs_add_delayed_data_ref(trans, &generic_ref,
4354					 ram_bytes, NULL, NULL);
4355	return ret;
4356}
4357
4358/*
4359 * this is used by the tree logging recovery code.  It records that
4360 * an extent has been allocated and makes sure to clear the free
4361 * space cache bits as well
4362 */
4363int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,
4364				   u64 root_objectid, u64 owner, u64 offset,
4365				   struct btrfs_key *ins)
4366{
4367	struct btrfs_fs_info *fs_info = trans->fs_info;
4368	int ret;
4369	struct btrfs_block_group_cache *block_group;
4370	struct btrfs_space_info *space_info;
4371
4372	/*
4373	 * Mixed block groups will exclude before processing the log so we only
4374	 * need to do the exclude dance if this fs isn't mixed.
4375	 */
4376	if (!btrfs_fs_incompat(fs_info, MIXED_GROUPS)) {
4377		ret = __exclude_logged_extent(fs_info, ins->objectid,
4378					      ins->offset);
4379		if (ret)
4380			return ret;
4381	}
4382
4383	block_group = btrfs_lookup_block_group(fs_info, ins->objectid);
4384	if (!block_group)
4385		return -EINVAL;
4386
4387	space_info = block_group->space_info;
4388	spin_lock(&space_info->lock);
4389	spin_lock(&block_group->lock);
4390	space_info->bytes_reserved += ins->offset;
4391	block_group->reserved += ins->offset;
4392	spin_unlock(&block_group->lock);
4393	spin_unlock(&space_info->lock);
4394
4395	ret = alloc_reserved_file_extent(trans, 0, root_objectid, 0, owner,
4396					 offset, ins, 1);
 
 
4397	btrfs_put_block_group(block_group);
4398	return ret;
4399}
4400
4401static struct extent_buffer *
4402btrfs_init_new_buffer(struct btrfs_trans_handle *trans, struct btrfs_root *root,
4403		      u64 bytenr, int level, u64 owner)
 
4404{
4405	struct btrfs_fs_info *fs_info = root->fs_info;
4406	struct extent_buffer *buf;
 
4407
4408	buf = btrfs_find_create_tree_block(fs_info, bytenr);
4409	if (IS_ERR(buf))
4410		return buf;
4411
4412	/*
4413	 * Extra safety check in case the extent tree is corrupted and extent
4414	 * allocator chooses to use a tree block which is already used and
4415	 * locked.
4416	 */
4417	if (buf->lock_owner == current->pid) {
4418		btrfs_err_rl(fs_info,
4419"tree block %llu owner %llu already locked by pid=%d, extent tree corruption detected",
4420			buf->start, btrfs_header_owner(buf), current->pid);
4421		free_extent_buffer(buf);
4422		return ERR_PTR(-EUCLEAN);
4423	}
4424
4425	btrfs_set_buffer_lockdep_class(root->root_key.objectid, buf, level);
4426	btrfs_tree_lock(buf);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4427	btrfs_clean_tree_block(buf);
4428	clear_bit(EXTENT_BUFFER_STALE, &buf->bflags);
 
4429
4430	btrfs_set_lock_blocking_write(buf);
4431	set_extent_buffer_uptodate(buf);
4432
4433	memzero_extent_buffer(buf, 0, sizeof(struct btrfs_header));
4434	btrfs_set_header_level(buf, level);
4435	btrfs_set_header_bytenr(buf, buf->start);
4436	btrfs_set_header_generation(buf, trans->transid);
4437	btrfs_set_header_backref_rev(buf, BTRFS_MIXED_BACKREF_REV);
4438	btrfs_set_header_owner(buf, owner);
4439	write_extent_buffer_fsid(buf, fs_info->fs_devices->metadata_uuid);
4440	write_extent_buffer_chunk_tree_uuid(buf, fs_info->chunk_tree_uuid);
4441	if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
4442		buf->log_index = root->log_transid % 2;
4443		/*
4444		 * we allow two log transactions at a time, use different
4445		 * EXTENT bit to differentiate dirty pages.
4446		 */
4447		if (buf->log_index == 0)
4448			set_extent_dirty(&root->dirty_log_pages, buf->start,
4449					buf->start + buf->len - 1, GFP_NOFS);
4450		else
4451			set_extent_new(&root->dirty_log_pages, buf->start,
4452					buf->start + buf->len - 1);
4453	} else {
4454		buf->log_index = -1;
4455		set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
4456			 buf->start + buf->len - 1, GFP_NOFS);
4457	}
4458	trans->dirty = true;
4459	/* this returns a buffer locked for blocking */
4460	return buf;
4461}
4462
4463/*
4464 * finds a free extent and does all the dirty work required for allocation
4465 * returns the tree buffer or an ERR_PTR on error.
4466 */
4467struct extent_buffer *btrfs_alloc_tree_block(struct btrfs_trans_handle *trans,
4468					     struct btrfs_root *root,
4469					     u64 parent, u64 root_objectid,
4470					     const struct btrfs_disk_key *key,
4471					     int level, u64 hint,
4472					     u64 empty_size)
 
4473{
4474	struct btrfs_fs_info *fs_info = root->fs_info;
4475	struct btrfs_key ins;
4476	struct btrfs_block_rsv *block_rsv;
4477	struct extent_buffer *buf;
4478	struct btrfs_delayed_extent_op *extent_op;
4479	struct btrfs_ref generic_ref = { 0 };
4480	u64 flags = 0;
4481	int ret;
4482	u32 blocksize = fs_info->nodesize;
4483	bool skinny_metadata = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
4484
4485#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
4486	if (btrfs_is_testing(fs_info)) {
4487		buf = btrfs_init_new_buffer(trans, root, root->alloc_bytenr,
4488					    level, root_objectid);
4489		if (!IS_ERR(buf))
4490			root->alloc_bytenr += blocksize;
4491		return buf;
4492	}
4493#endif
4494
4495	block_rsv = btrfs_use_block_rsv(trans, root, blocksize);
4496	if (IS_ERR(block_rsv))
4497		return ERR_CAST(block_rsv);
4498
4499	ret = btrfs_reserve_extent(root, blocksize, blocksize, blocksize,
4500				   empty_size, hint, &ins, 0, 0);
4501	if (ret)
4502		goto out_unuse;
4503
4504	buf = btrfs_init_new_buffer(trans, root, ins.objectid, level,
4505				    root_objectid);
4506	if (IS_ERR(buf)) {
4507		ret = PTR_ERR(buf);
4508		goto out_free_reserved;
4509	}
4510
4511	if (root_objectid == BTRFS_TREE_RELOC_OBJECTID) {
4512		if (parent == 0)
4513			parent = ins.objectid;
4514		flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF;
4515	} else
4516		BUG_ON(parent > 0);
4517
4518	if (root_objectid != BTRFS_TREE_LOG_OBJECTID) {
4519		extent_op = btrfs_alloc_delayed_extent_op();
4520		if (!extent_op) {
4521			ret = -ENOMEM;
4522			goto out_free_buf;
4523		}
4524		if (key)
4525			memcpy(&extent_op->key, key, sizeof(extent_op->key));
4526		else
4527			memset(&extent_op->key, 0, sizeof(extent_op->key));
4528		extent_op->flags_to_set = flags;
4529		extent_op->update_key = skinny_metadata ? false : true;
4530		extent_op->update_flags = true;
4531		extent_op->is_data = false;
4532		extent_op->level = level;
4533
4534		btrfs_init_generic_ref(&generic_ref, BTRFS_ADD_DELAYED_EXTENT,
4535				       ins.objectid, ins.offset, parent);
4536		generic_ref.real_root = root->root_key.objectid;
4537		btrfs_init_tree_ref(&generic_ref, level, root_objectid);
4538		btrfs_ref_tree_mod(fs_info, &generic_ref);
4539		ret = btrfs_add_delayed_tree_ref(trans, &generic_ref,
4540						 extent_op, NULL, NULL);
4541		if (ret)
4542			goto out_free_delayed;
4543	}
4544	return buf;
4545
4546out_free_delayed:
4547	btrfs_free_delayed_extent_op(extent_op);
4548out_free_buf:
 
4549	free_extent_buffer(buf);
4550out_free_reserved:
4551	btrfs_free_reserved_extent(fs_info, ins.objectid, ins.offset, 0);
4552out_unuse:
4553	btrfs_unuse_block_rsv(fs_info, block_rsv, blocksize);
4554	return ERR_PTR(ret);
4555}
4556
4557struct walk_control {
4558	u64 refs[BTRFS_MAX_LEVEL];
4559	u64 flags[BTRFS_MAX_LEVEL];
4560	struct btrfs_key update_progress;
4561	struct btrfs_key drop_progress;
4562	int drop_level;
4563	int stage;
4564	int level;
4565	int shared_level;
4566	int update_ref;
4567	int keep_locks;
4568	int reada_slot;
4569	int reada_count;
4570	int restarted;
4571};
4572
4573#define DROP_REFERENCE	1
4574#define UPDATE_BACKREF	2
4575
4576static noinline void reada_walk_down(struct btrfs_trans_handle *trans,
4577				     struct btrfs_root *root,
4578				     struct walk_control *wc,
4579				     struct btrfs_path *path)
4580{
4581	struct btrfs_fs_info *fs_info = root->fs_info;
4582	u64 bytenr;
4583	u64 generation;
4584	u64 refs;
4585	u64 flags;
4586	u32 nritems;
4587	struct btrfs_key key;
4588	struct extent_buffer *eb;
4589	int ret;
4590	int slot;
4591	int nread = 0;
4592
4593	if (path->slots[wc->level] < wc->reada_slot) {
4594		wc->reada_count = wc->reada_count * 2 / 3;
4595		wc->reada_count = max(wc->reada_count, 2);
4596	} else {
4597		wc->reada_count = wc->reada_count * 3 / 2;
4598		wc->reada_count = min_t(int, wc->reada_count,
4599					BTRFS_NODEPTRS_PER_BLOCK(fs_info));
4600	}
4601
4602	eb = path->nodes[wc->level];
4603	nritems = btrfs_header_nritems(eb);
4604
4605	for (slot = path->slots[wc->level]; slot < nritems; slot++) {
4606		if (nread >= wc->reada_count)
4607			break;
4608
4609		cond_resched();
4610		bytenr = btrfs_node_blockptr(eb, slot);
4611		generation = btrfs_node_ptr_generation(eb, slot);
4612
4613		if (slot == path->slots[wc->level])
4614			goto reada;
4615
4616		if (wc->stage == UPDATE_BACKREF &&
4617		    generation <= root->root_key.offset)
4618			continue;
4619
4620		/* We don't lock the tree block, it's OK to be racy here */
4621		ret = btrfs_lookup_extent_info(trans, fs_info, bytenr,
4622					       wc->level - 1, 1, &refs,
4623					       &flags);
4624		/* We don't care about errors in readahead. */
4625		if (ret < 0)
4626			continue;
4627		BUG_ON(refs == 0);
4628
4629		if (wc->stage == DROP_REFERENCE) {
4630			if (refs == 1)
4631				goto reada;
4632
4633			if (wc->level == 1 &&
4634			    (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
4635				continue;
4636			if (!wc->update_ref ||
4637			    generation <= root->root_key.offset)
4638				continue;
4639			btrfs_node_key_to_cpu(eb, &key, slot);
4640			ret = btrfs_comp_cpu_keys(&key,
4641						  &wc->update_progress);
4642			if (ret < 0)
4643				continue;
4644		} else {
4645			if (wc->level == 1 &&
4646			    (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
4647				continue;
4648		}
4649reada:
4650		readahead_tree_block(fs_info, bytenr);
4651		nread++;
4652	}
4653	wc->reada_slot = slot;
4654}
4655
4656/*
4657 * helper to process tree block while walking down the tree.
4658 *
4659 * when wc->stage == UPDATE_BACKREF, this function updates
4660 * back refs for pointers in the block.
4661 *
4662 * NOTE: return value 1 means we should stop walking down.
4663 */
4664static noinline int walk_down_proc(struct btrfs_trans_handle *trans,
4665				   struct btrfs_root *root,
4666				   struct btrfs_path *path,
4667				   struct walk_control *wc, int lookup_info)
4668{
4669	struct btrfs_fs_info *fs_info = root->fs_info;
4670	int level = wc->level;
4671	struct extent_buffer *eb = path->nodes[level];
4672	u64 flag = BTRFS_BLOCK_FLAG_FULL_BACKREF;
4673	int ret;
4674
4675	if (wc->stage == UPDATE_BACKREF &&
4676	    btrfs_header_owner(eb) != root->root_key.objectid)
4677		return 1;
4678
4679	/*
4680	 * when reference count of tree block is 1, it won't increase
4681	 * again. once full backref flag is set, we never clear it.
4682	 */
4683	if (lookup_info &&
4684	    ((wc->stage == DROP_REFERENCE && wc->refs[level] != 1) ||
4685	     (wc->stage == UPDATE_BACKREF && !(wc->flags[level] & flag)))) {
4686		BUG_ON(!path->locks[level]);
4687		ret = btrfs_lookup_extent_info(trans, fs_info,
4688					       eb->start, level, 1,
4689					       &wc->refs[level],
4690					       &wc->flags[level]);
4691		BUG_ON(ret == -ENOMEM);
4692		if (ret)
4693			return ret;
4694		BUG_ON(wc->refs[level] == 0);
4695	}
4696
4697	if (wc->stage == DROP_REFERENCE) {
4698		if (wc->refs[level] > 1)
4699			return 1;
4700
4701		if (path->locks[level] && !wc->keep_locks) {
4702			btrfs_tree_unlock_rw(eb, path->locks[level]);
4703			path->locks[level] = 0;
4704		}
4705		return 0;
4706	}
4707
4708	/* wc->stage == UPDATE_BACKREF */
4709	if (!(wc->flags[level] & flag)) {
4710		BUG_ON(!path->locks[level]);
4711		ret = btrfs_inc_ref(trans, root, eb, 1);
4712		BUG_ON(ret); /* -ENOMEM */
4713		ret = btrfs_dec_ref(trans, root, eb, 0);
4714		BUG_ON(ret); /* -ENOMEM */
4715		ret = btrfs_set_disk_extent_flags(trans, eb->start,
4716						  eb->len, flag,
4717						  btrfs_header_level(eb), 0);
4718		BUG_ON(ret); /* -ENOMEM */
4719		wc->flags[level] |= flag;
4720	}
4721
4722	/*
4723	 * the block is shared by multiple trees, so it's not good to
4724	 * keep the tree lock
4725	 */
4726	if (path->locks[level] && level > 0) {
4727		btrfs_tree_unlock_rw(eb, path->locks[level]);
4728		path->locks[level] = 0;
4729	}
4730	return 0;
4731}
4732
4733/*
4734 * This is used to verify a ref exists for this root to deal with a bug where we
4735 * would have a drop_progress key that hadn't been updated properly.
4736 */
4737static int check_ref_exists(struct btrfs_trans_handle *trans,
4738			    struct btrfs_root *root, u64 bytenr, u64 parent,
4739			    int level)
4740{
4741	struct btrfs_path *path;
4742	struct btrfs_extent_inline_ref *iref;
4743	int ret;
4744
4745	path = btrfs_alloc_path();
4746	if (!path)
4747		return -ENOMEM;
4748
4749	ret = lookup_extent_backref(trans, path, &iref, bytenr,
4750				    root->fs_info->nodesize, parent,
4751				    root->root_key.objectid, level, 0);
4752	btrfs_free_path(path);
4753	if (ret == -ENOENT)
4754		return 0;
4755	if (ret < 0)
4756		return ret;
4757	return 1;
4758}
4759
4760/*
4761 * helper to process tree block pointer.
4762 *
4763 * when wc->stage == DROP_REFERENCE, this function checks
4764 * reference count of the block pointed to. if the block
4765 * is shared and we need update back refs for the subtree
4766 * rooted at the block, this function changes wc->stage to
4767 * UPDATE_BACKREF. if the block is shared and there is no
4768 * need to update back, this function drops the reference
4769 * to the block.
4770 *
4771 * NOTE: return value 1 means we should stop walking down.
4772 */
4773static noinline int do_walk_down(struct btrfs_trans_handle *trans,
4774				 struct btrfs_root *root,
4775				 struct btrfs_path *path,
4776				 struct walk_control *wc, int *lookup_info)
4777{
4778	struct btrfs_fs_info *fs_info = root->fs_info;
4779	u64 bytenr;
4780	u64 generation;
4781	u64 parent;
 
4782	struct btrfs_key key;
4783	struct btrfs_key first_key;
4784	struct btrfs_ref ref = { 0 };
4785	struct extent_buffer *next;
4786	int level = wc->level;
4787	int reada = 0;
4788	int ret = 0;
4789	bool need_account = false;
4790
4791	generation = btrfs_node_ptr_generation(path->nodes[level],
4792					       path->slots[level]);
4793	/*
4794	 * if the lower level block was created before the snapshot
4795	 * was created, we know there is no need to update back refs
4796	 * for the subtree
4797	 */
4798	if (wc->stage == UPDATE_BACKREF &&
4799	    generation <= root->root_key.offset) {
4800		*lookup_info = 1;
4801		return 1;
4802	}
4803
4804	bytenr = btrfs_node_blockptr(path->nodes[level], path->slots[level]);
4805	btrfs_node_key_to_cpu(path->nodes[level], &first_key,
 
 
 
 
 
4806			      path->slots[level]);
4807
4808	next = find_extent_buffer(fs_info, bytenr);
4809	if (!next) {
4810		next = btrfs_find_create_tree_block(fs_info, bytenr);
 
4811		if (IS_ERR(next))
4812			return PTR_ERR(next);
4813
4814		btrfs_set_buffer_lockdep_class(root->root_key.objectid, next,
4815					       level - 1);
4816		reada = 1;
4817	}
4818	btrfs_tree_lock(next);
4819	btrfs_set_lock_blocking_write(next);
4820
4821	ret = btrfs_lookup_extent_info(trans, fs_info, bytenr, level - 1, 1,
4822				       &wc->refs[level - 1],
4823				       &wc->flags[level - 1]);
4824	if (ret < 0)
4825		goto out_unlock;
4826
4827	if (unlikely(wc->refs[level - 1] == 0)) {
4828		btrfs_err(fs_info, "Missing references.");
4829		ret = -EIO;
4830		goto out_unlock;
4831	}
4832	*lookup_info = 0;
4833
4834	if (wc->stage == DROP_REFERENCE) {
4835		if (wc->refs[level - 1] > 1) {
4836			need_account = true;
4837			if (level == 1 &&
4838			    (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
4839				goto skip;
4840
4841			if (!wc->update_ref ||
4842			    generation <= root->root_key.offset)
4843				goto skip;
4844
4845			btrfs_node_key_to_cpu(path->nodes[level], &key,
4846					      path->slots[level]);
4847			ret = btrfs_comp_cpu_keys(&key, &wc->update_progress);
4848			if (ret < 0)
4849				goto skip;
4850
4851			wc->stage = UPDATE_BACKREF;
4852			wc->shared_level = level - 1;
4853		}
4854	} else {
4855		if (level == 1 &&
4856		    (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
4857			goto skip;
4858	}
4859
4860	if (!btrfs_buffer_uptodate(next, generation, 0)) {
4861		btrfs_tree_unlock(next);
4862		free_extent_buffer(next);
4863		next = NULL;
4864		*lookup_info = 1;
4865	}
4866
4867	if (!next) {
4868		if (reada && level == 1)
4869			reada_walk_down(trans, root, wc, path);
4870		next = read_tree_block(fs_info, bytenr, generation, level - 1,
4871				       &first_key);
4872		if (IS_ERR(next)) {
4873			return PTR_ERR(next);
4874		} else if (!extent_buffer_uptodate(next)) {
4875			free_extent_buffer(next);
4876			return -EIO;
4877		}
4878		btrfs_tree_lock(next);
4879		btrfs_set_lock_blocking_write(next);
4880	}
4881
4882	level--;
4883	ASSERT(level == btrfs_header_level(next));
4884	if (level != btrfs_header_level(next)) {
4885		btrfs_err(root->fs_info, "mismatched level");
4886		ret = -EIO;
4887		goto out_unlock;
4888	}
4889	path->nodes[level] = next;
4890	path->slots[level] = 0;
4891	path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
4892	wc->level = level;
4893	if (wc->level == 1)
4894		wc->reada_slot = 0;
4895	return 0;
4896skip:
4897	wc->refs[level - 1] = 0;
4898	wc->flags[level - 1] = 0;
4899	if (wc->stage == DROP_REFERENCE) {
4900		if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF) {
4901			parent = path->nodes[level]->start;
4902		} else {
4903			ASSERT(root->root_key.objectid ==
4904			       btrfs_header_owner(path->nodes[level]));
4905			if (root->root_key.objectid !=
4906			    btrfs_header_owner(path->nodes[level])) {
4907				btrfs_err(root->fs_info,
4908						"mismatched block owner");
4909				ret = -EIO;
4910				goto out_unlock;
4911			}
4912			parent = 0;
4913		}
4914
4915		/*
4916		 * If we had a drop_progress we need to verify the refs are set
4917		 * as expected.  If we find our ref then we know that from here
4918		 * on out everything should be correct, and we can clear the
4919		 * ->restarted flag.
4920		 */
4921		if (wc->restarted) {
4922			ret = check_ref_exists(trans, root, bytenr, parent,
4923					       level - 1);
4924			if (ret < 0)
4925				goto out_unlock;
4926			if (ret == 0)
4927				goto no_delete;
4928			ret = 0;
4929			wc->restarted = 0;
4930		}
4931
4932		/*
4933		 * Reloc tree doesn't contribute to qgroup numbers, and we have
4934		 * already accounted them at merge time (replace_path),
4935		 * thus we could skip expensive subtree trace here.
4936		 */
4937		if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID &&
4938		    need_account) {
4939			ret = btrfs_qgroup_trace_subtree(trans, next,
4940							 generation, level - 1);
4941			if (ret) {
4942				btrfs_err_rl(fs_info,
4943					     "Error %d accounting shared subtree. Quota is out of sync, rescan required.",
4944					     ret);
4945			}
4946		}
4947
4948		/*
4949		 * We need to update the next key in our walk control so we can
4950		 * update the drop_progress key accordingly.  We don't care if
4951		 * find_next_key doesn't find a key because that means we're at
4952		 * the end and are going to clean up now.
4953		 */
4954		wc->drop_level = level;
4955		find_next_key(path, level, &wc->drop_progress);
4956
4957		btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF, bytenr,
4958				       fs_info->nodesize, parent);
4959		btrfs_init_tree_ref(&ref, level - 1, root->root_key.objectid);
 
4960		ret = btrfs_free_extent(trans, &ref);
4961		if (ret)
4962			goto out_unlock;
4963	}
4964no_delete:
4965	*lookup_info = 1;
4966	ret = 1;
4967
4968out_unlock:
4969	btrfs_tree_unlock(next);
4970	free_extent_buffer(next);
4971
4972	return ret;
4973}
4974
4975/*
4976 * helper to process tree block while walking up the tree.
4977 *
4978 * when wc->stage == DROP_REFERENCE, this function drops
4979 * reference count on the block.
4980 *
4981 * when wc->stage == UPDATE_BACKREF, this function changes
4982 * wc->stage back to DROP_REFERENCE if we changed wc->stage
4983 * to UPDATE_BACKREF previously while processing the block.
4984 *
4985 * NOTE: return value 1 means we should stop walking up.
4986 */
4987static noinline int walk_up_proc(struct btrfs_trans_handle *trans,
4988				 struct btrfs_root *root,
4989				 struct btrfs_path *path,
4990				 struct walk_control *wc)
4991{
4992	struct btrfs_fs_info *fs_info = root->fs_info;
4993	int ret;
4994	int level = wc->level;
4995	struct extent_buffer *eb = path->nodes[level];
4996	u64 parent = 0;
4997
4998	if (wc->stage == UPDATE_BACKREF) {
4999		BUG_ON(wc->shared_level < level);
5000		if (level < wc->shared_level)
5001			goto out;
5002
5003		ret = find_next_key(path, level + 1, &wc->update_progress);
5004		if (ret > 0)
5005			wc->update_ref = 0;
5006
5007		wc->stage = DROP_REFERENCE;
5008		wc->shared_level = -1;
5009		path->slots[level] = 0;
5010
5011		/*
5012		 * check reference count again if the block isn't locked.
5013		 * we should start walking down the tree again if reference
5014		 * count is one.
5015		 */
5016		if (!path->locks[level]) {
5017			BUG_ON(level == 0);
5018			btrfs_tree_lock(eb);
5019			btrfs_set_lock_blocking_write(eb);
5020			path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
5021
5022			ret = btrfs_lookup_extent_info(trans, fs_info,
5023						       eb->start, level, 1,
5024						       &wc->refs[level],
5025						       &wc->flags[level]);
5026			if (ret < 0) {
5027				btrfs_tree_unlock_rw(eb, path->locks[level]);
5028				path->locks[level] = 0;
5029				return ret;
5030			}
5031			BUG_ON(wc->refs[level] == 0);
5032			if (wc->refs[level] == 1) {
5033				btrfs_tree_unlock_rw(eb, path->locks[level]);
5034				path->locks[level] = 0;
5035				return 1;
5036			}
5037		}
5038	}
5039
5040	/* wc->stage == DROP_REFERENCE */
5041	BUG_ON(wc->refs[level] > 1 && !path->locks[level]);
5042
5043	if (wc->refs[level] == 1) {
5044		if (level == 0) {
5045			if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
5046				ret = btrfs_dec_ref(trans, root, eb, 1);
5047			else
5048				ret = btrfs_dec_ref(trans, root, eb, 0);
5049			BUG_ON(ret); /* -ENOMEM */
5050			if (is_fstree(root->root_key.objectid)) {
5051				ret = btrfs_qgroup_trace_leaf_items(trans, eb);
5052				if (ret) {
5053					btrfs_err_rl(fs_info,
5054	"error %d accounting leaf items, quota is out of sync, rescan required",
5055					     ret);
5056				}
5057			}
5058		}
5059		/* make block locked assertion in btrfs_clean_tree_block happy */
5060		if (!path->locks[level] &&
5061		    btrfs_header_generation(eb) == trans->transid) {
5062			btrfs_tree_lock(eb);
5063			btrfs_set_lock_blocking_write(eb);
5064			path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
5065		}
5066		btrfs_clean_tree_block(eb);
5067	}
5068
5069	if (eb == root->node) {
5070		if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
5071			parent = eb->start;
5072		else if (root->root_key.objectid != btrfs_header_owner(eb))
5073			goto owner_mismatch;
5074	} else {
5075		if (wc->flags[level + 1] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
5076			parent = path->nodes[level + 1]->start;
5077		else if (root->root_key.objectid !=
5078			 btrfs_header_owner(path->nodes[level + 1]))
5079			goto owner_mismatch;
5080	}
5081
5082	btrfs_free_tree_block(trans, root, eb, parent, wc->refs[level] == 1);
 
5083out:
5084	wc->refs[level] = 0;
5085	wc->flags[level] = 0;
5086	return 0;
5087
5088owner_mismatch:
5089	btrfs_err_rl(fs_info, "unexpected tree owner, have %llu expect %llu",
5090		     btrfs_header_owner(eb), root->root_key.objectid);
5091	return -EUCLEAN;
5092}
5093
5094static noinline int walk_down_tree(struct btrfs_trans_handle *trans,
5095				   struct btrfs_root *root,
5096				   struct btrfs_path *path,
5097				   struct walk_control *wc)
5098{
5099	int level = wc->level;
5100	int lookup_info = 1;
5101	int ret;
5102
5103	while (level >= 0) {
5104		ret = walk_down_proc(trans, root, path, wc, lookup_info);
5105		if (ret > 0)
5106			break;
5107
5108		if (level == 0)
5109			break;
5110
5111		if (path->slots[level] >=
5112		    btrfs_header_nritems(path->nodes[level]))
5113			break;
5114
5115		ret = do_walk_down(trans, root, path, wc, &lookup_info);
5116		if (ret > 0) {
5117			path->slots[level]++;
5118			continue;
5119		} else if (ret < 0)
5120			return ret;
5121		level = wc->level;
5122	}
5123	return 0;
5124}
5125
5126static noinline int walk_up_tree(struct btrfs_trans_handle *trans,
5127				 struct btrfs_root *root,
5128				 struct btrfs_path *path,
5129				 struct walk_control *wc, int max_level)
5130{
5131	int level = wc->level;
5132	int ret;
5133
5134	path->slots[level] = btrfs_header_nritems(path->nodes[level]);
5135	while (level < max_level && path->nodes[level]) {
5136		wc->level = level;
5137		if (path->slots[level] + 1 <
5138		    btrfs_header_nritems(path->nodes[level])) {
5139			path->slots[level]++;
5140			return 0;
5141		} else {
5142			ret = walk_up_proc(trans, root, path, wc);
5143			if (ret > 0)
5144				return 0;
5145			if (ret < 0)
5146				return ret;
5147
5148			if (path->locks[level]) {
5149				btrfs_tree_unlock_rw(path->nodes[level],
5150						     path->locks[level]);
5151				path->locks[level] = 0;
5152			}
5153			free_extent_buffer(path->nodes[level]);
5154			path->nodes[level] = NULL;
5155			level++;
5156		}
5157	}
5158	return 1;
5159}
5160
5161/*
5162 * drop a subvolume tree.
5163 *
5164 * this function traverses the tree freeing any blocks that only
5165 * referenced by the tree.
5166 *
5167 * when a shared tree block is found. this function decreases its
5168 * reference count by one. if update_ref is true, this function
5169 * also make sure backrefs for the shared block and all lower level
5170 * blocks are properly updated.
5171 *
5172 * If called with for_reloc == 0, may exit early with -EAGAIN
5173 */
5174int btrfs_drop_snapshot(struct btrfs_root *root,
5175			 struct btrfs_block_rsv *block_rsv, int update_ref,
5176			 int for_reloc)
5177{
 
 
5178	struct btrfs_fs_info *fs_info = root->fs_info;
5179	struct btrfs_path *path;
5180	struct btrfs_trans_handle *trans;
5181	struct btrfs_root *tree_root = fs_info->tree_root;
5182	struct btrfs_root_item *root_item = &root->root_item;
5183	struct walk_control *wc;
5184	struct btrfs_key key;
5185	int err = 0;
5186	int ret;
5187	int level;
5188	bool root_dropped = false;
 
5189
5190	btrfs_debug(fs_info, "Drop subvolume %llu", root->root_key.objectid);
5191
5192	path = btrfs_alloc_path();
5193	if (!path) {
5194		err = -ENOMEM;
5195		goto out;
5196	}
5197
5198	wc = kzalloc(sizeof(*wc), GFP_NOFS);
5199	if (!wc) {
5200		btrfs_free_path(path);
5201		err = -ENOMEM;
5202		goto out;
5203	}
5204
5205	trans = btrfs_start_transaction(tree_root, 0);
 
 
 
 
 
 
 
5206	if (IS_ERR(trans)) {
5207		err = PTR_ERR(trans);
5208		goto out_free;
5209	}
5210
5211	err = btrfs_run_delayed_items(trans);
5212	if (err)
5213		goto out_end_trans;
5214
5215	if (block_rsv)
5216		trans->block_rsv = block_rsv;
5217
5218	/*
5219	 * This will help us catch people modifying the fs tree while we're
5220	 * dropping it.  It is unsafe to mess with the fs tree while it's being
5221	 * dropped as we unlock the root node and parent nodes as we walk down
5222	 * the tree, assuming nothing will change.  If something does change
5223	 * then we'll have stale information and drop references to blocks we've
5224	 * already dropped.
5225	 */
5226	set_bit(BTRFS_ROOT_DELETING, &root->state);
 
 
5227	if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
5228		level = btrfs_header_level(root->node);
5229		path->nodes[level] = btrfs_lock_root_node(root);
5230		btrfs_set_lock_blocking_write(path->nodes[level]);
5231		path->slots[level] = 0;
5232		path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
5233		memset(&wc->update_progress, 0,
5234		       sizeof(wc->update_progress));
5235	} else {
5236		btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
5237		memcpy(&wc->update_progress, &key,
5238		       sizeof(wc->update_progress));
5239
5240		level = root_item->drop_level;
5241		BUG_ON(level == 0);
5242		path->lowest_level = level;
5243		ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
5244		path->lowest_level = 0;
5245		if (ret < 0) {
5246			err = ret;
5247			goto out_end_trans;
5248		}
5249		WARN_ON(ret > 0);
5250
5251		/*
5252		 * unlock our path, this is safe because only this
5253		 * function is allowed to delete this snapshot
5254		 */
5255		btrfs_unlock_up_safe(path, 0);
5256
5257		level = btrfs_header_level(root->node);
5258		while (1) {
5259			btrfs_tree_lock(path->nodes[level]);
5260			btrfs_set_lock_blocking_write(path->nodes[level]);
5261			path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
5262
5263			ret = btrfs_lookup_extent_info(trans, fs_info,
5264						path->nodes[level]->start,
5265						level, 1, &wc->refs[level],
5266						&wc->flags[level]);
5267			if (ret < 0) {
5268				err = ret;
5269				goto out_end_trans;
5270			}
5271			BUG_ON(wc->refs[level] == 0);
5272
5273			if (level == root_item->drop_level)
5274				break;
5275
5276			btrfs_tree_unlock(path->nodes[level]);
5277			path->locks[level] = 0;
5278			WARN_ON(wc->refs[level] != 1);
5279			level--;
5280		}
5281	}
5282
5283	wc->restarted = test_bit(BTRFS_ROOT_DEAD_TREE, &root->state);
5284	wc->level = level;
5285	wc->shared_level = -1;
5286	wc->stage = DROP_REFERENCE;
5287	wc->update_ref = update_ref;
5288	wc->keep_locks = 0;
5289	wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(fs_info);
5290
5291	while (1) {
5292
5293		ret = walk_down_tree(trans, root, path, wc);
5294		if (ret < 0) {
5295			err = ret;
5296			break;
5297		}
5298
5299		ret = walk_up_tree(trans, root, path, wc, BTRFS_MAX_LEVEL);
5300		if (ret < 0) {
5301			err = ret;
5302			break;
5303		}
5304
5305		if (ret > 0) {
5306			BUG_ON(wc->stage != DROP_REFERENCE);
5307			break;
5308		}
5309
5310		if (wc->stage == DROP_REFERENCE) {
5311			wc->drop_level = wc->level;
5312			btrfs_node_key_to_cpu(path->nodes[wc->drop_level],
5313					      &wc->drop_progress,
5314					      path->slots[wc->drop_level]);
5315		}
5316		btrfs_cpu_key_to_disk(&root_item->drop_progress,
5317				      &wc->drop_progress);
5318		root_item->drop_level = wc->drop_level;
5319
5320		BUG_ON(wc->level == 0);
5321		if (btrfs_should_end_transaction(trans) ||
5322		    (!for_reloc && btrfs_need_cleaner_sleep(fs_info))) {
5323			ret = btrfs_update_root(trans, tree_root,
5324						&root->root_key,
5325						root_item);
5326			if (ret) {
5327				btrfs_abort_transaction(trans, ret);
5328				err = ret;
5329				goto out_end_trans;
5330			}
5331
 
 
 
5332			btrfs_end_transaction_throttle(trans);
5333			if (!for_reloc && btrfs_need_cleaner_sleep(fs_info)) {
5334				btrfs_debug(fs_info,
5335					    "drop snapshot early exit");
5336				err = -EAGAIN;
5337				goto out_free;
5338			}
5339
5340			trans = btrfs_start_transaction(tree_root, 0);
 
 
 
 
 
 
 
 
5341			if (IS_ERR(trans)) {
5342				err = PTR_ERR(trans);
5343				goto out_free;
5344			}
5345			if (block_rsv)
5346				trans->block_rsv = block_rsv;
5347		}
5348	}
5349	btrfs_release_path(path);
5350	if (err)
5351		goto out_end_trans;
5352
5353	ret = btrfs_del_root(trans, &root->root_key);
5354	if (ret) {
5355		btrfs_abort_transaction(trans, ret);
5356		err = ret;
5357		goto out_end_trans;
5358	}
5359
5360	if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
5361		ret = btrfs_find_root(tree_root, &root->root_key, path,
5362				      NULL, NULL);
5363		if (ret < 0) {
5364			btrfs_abort_transaction(trans, ret);
5365			err = ret;
5366			goto out_end_trans;
5367		} else if (ret > 0) {
5368			/* if we fail to delete the orphan item this time
5369			 * around, it'll get picked up the next time.
5370			 *
5371			 * The most common failure here is just -ENOENT.
5372			 */
5373			btrfs_del_orphan_item(trans, tree_root,
5374					      root->root_key.objectid);
5375		}
5376	}
5377
5378	if (test_bit(BTRFS_ROOT_IN_RADIX, &root->state)) {
 
 
 
 
 
 
 
 
5379		btrfs_add_dropped_root(trans, root);
5380	} else {
5381		free_extent_buffer(root->node);
5382		free_extent_buffer(root->commit_root);
5383		btrfs_put_fs_root(root);
5384	}
5385	root_dropped = true;
5386out_end_trans:
 
 
 
5387	btrfs_end_transaction_throttle(trans);
5388out_free:
5389	kfree(wc);
5390	btrfs_free_path(path);
5391out:
5392	/*
 
 
 
 
 
 
 
5393	 * So if we need to stop dropping the snapshot for whatever reason we
5394	 * need to make sure to add it back to the dead root list so that we
5395	 * keep trying to do the work later.  This also cleans up roots if we
5396	 * don't have it in the radix (like when we recover after a power fail
5397	 * or unmount) so we don't leak memory.
5398	 */
5399	if (!for_reloc && !root_dropped)
5400		btrfs_add_dead_root(root);
5401	if (err && err != -EAGAIN)
5402		btrfs_handle_fs_error(fs_info, err, NULL);
5403	return err;
5404}
5405
5406/*
5407 * drop subtree rooted at tree block 'node'.
5408 *
5409 * NOTE: this function will unlock and release tree block 'node'
5410 * only used by relocation code
5411 */
5412int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
5413			struct btrfs_root *root,
5414			struct extent_buffer *node,
5415			struct extent_buffer *parent)
5416{
5417	struct btrfs_fs_info *fs_info = root->fs_info;
5418	struct btrfs_path *path;
5419	struct walk_control *wc;
5420	int level;
5421	int parent_level;
5422	int ret = 0;
5423	int wret;
5424
5425	BUG_ON(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
5426
5427	path = btrfs_alloc_path();
5428	if (!path)
5429		return -ENOMEM;
5430
5431	wc = kzalloc(sizeof(*wc), GFP_NOFS);
5432	if (!wc) {
5433		btrfs_free_path(path);
5434		return -ENOMEM;
5435	}
5436
5437	btrfs_assert_tree_locked(parent);
5438	parent_level = btrfs_header_level(parent);
5439	extent_buffer_get(parent);
5440	path->nodes[parent_level] = parent;
5441	path->slots[parent_level] = btrfs_header_nritems(parent);
5442
5443	btrfs_assert_tree_locked(node);
5444	level = btrfs_header_level(node);
5445	path->nodes[level] = node;
5446	path->slots[level] = 0;
5447	path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
5448
5449	wc->refs[parent_level] = 1;
5450	wc->flags[parent_level] = BTRFS_BLOCK_FLAG_FULL_BACKREF;
5451	wc->level = level;
5452	wc->shared_level = -1;
5453	wc->stage = DROP_REFERENCE;
5454	wc->update_ref = 0;
5455	wc->keep_locks = 1;
5456	wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(fs_info);
5457
5458	while (1) {
5459		wret = walk_down_tree(trans, root, path, wc);
5460		if (wret < 0) {
5461			ret = wret;
5462			break;
5463		}
5464
5465		wret = walk_up_tree(trans, root, path, wc, parent_level);
5466		if (wret < 0)
5467			ret = wret;
5468		if (wret != 0)
5469			break;
5470	}
5471
5472	kfree(wc);
5473	btrfs_free_path(path);
5474	return ret;
5475}
5476
5477/*
5478 * helper to account the unused space of all the readonly block group in the
5479 * space_info. takes mirrors into account.
5480 */
5481u64 btrfs_account_ro_block_groups_free_space(struct btrfs_space_info *sinfo)
5482{
5483	struct btrfs_block_group_cache *block_group;
5484	u64 free_bytes = 0;
5485	int factor;
5486
5487	/* It's df, we don't care if it's racy */
5488	if (list_empty(&sinfo->ro_bgs))
5489		return 0;
5490
5491	spin_lock(&sinfo->lock);
5492	list_for_each_entry(block_group, &sinfo->ro_bgs, ro_list) {
5493		spin_lock(&block_group->lock);
5494
5495		if (!block_group->ro) {
5496			spin_unlock(&block_group->lock);
5497			continue;
5498		}
5499
5500		factor = btrfs_bg_type_to_factor(block_group->flags);
5501		free_bytes += (block_group->key.offset -
5502			       btrfs_block_group_used(&block_group->item)) *
5503			       factor;
5504
5505		spin_unlock(&block_group->lock);
5506	}
5507	spin_unlock(&sinfo->lock);
5508
5509	return free_bytes;
5510}
5511
5512int btrfs_error_unpin_extent_range(struct btrfs_fs_info *fs_info,
5513				   u64 start, u64 end)
5514{
5515	return unpin_extent_range(fs_info, start, end, false);
5516}
5517
5518/*
5519 * It used to be that old block groups would be left around forever.
5520 * Iterating over them would be enough to trim unused space.  Since we
5521 * now automatically remove them, we also need to iterate over unallocated
5522 * space.
5523 *
5524 * We don't want a transaction for this since the discard may take a
5525 * substantial amount of time.  We don't require that a transaction be
5526 * running, but we do need to take a running transaction into account
5527 * to ensure that we're not discarding chunks that were released or
5528 * allocated in the current transaction.
5529 *
5530 * Holding the chunks lock will prevent other threads from allocating
5531 * or releasing chunks, but it won't prevent a running transaction
5532 * from committing and releasing the memory that the pending chunks
5533 * list head uses.  For that, we need to take a reference to the
5534 * transaction and hold the commit root sem.  We only need to hold
5535 * it while performing the free space search since we have already
5536 * held back allocations.
5537 */
5538static int btrfs_trim_free_extents(struct btrfs_device *device, u64 *trimmed)
5539{
5540	u64 start = SZ_1M, len = 0, end = 0;
5541	int ret;
5542
5543	*trimmed = 0;
5544
5545	/* Discard not supported = nothing to do. */
5546	if (!blk_queue_discard(bdev_get_queue(device->bdev)))
5547		return 0;
5548
5549	/* Not writable = nothing to do. */
5550	if (!test_bit(BTRFS_DEV_STATE_WRITEABLE, &device->dev_state))
5551		return 0;
5552
5553	/* No free space = nothing to do. */
5554	if (device->total_bytes <= device->bytes_used)
5555		return 0;
5556
5557	ret = 0;
5558
5559	while (1) {
5560		struct btrfs_fs_info *fs_info = device->fs_info;
5561		u64 bytes;
5562
5563		ret = mutex_lock_interruptible(&fs_info->chunk_mutex);
5564		if (ret)
5565			break;
5566
5567		find_first_clear_extent_bit(&device->alloc_state, start,
5568					    &start, &end,
5569					    CHUNK_TRIMMED | CHUNK_ALLOCATED);
5570
5571		/* Ensure we skip the reserved area in the first 1M */
5572		start = max_t(u64, start, SZ_1M);
 
 
 
 
 
 
 
 
 
 
 
 
 
5573
5574		/*
5575		 * If find_first_clear_extent_bit find a range that spans the
5576		 * end of the device it will set end to -1, in this case it's up
5577		 * to the caller to trim the value to the size of the device.
5578		 */
5579		end = min(end, device->total_bytes - 1);
5580
5581		len = end - start + 1;
5582
5583		/* We didn't find any extents */
5584		if (!len) {
5585			mutex_unlock(&fs_info->chunk_mutex);
5586			ret = 0;
5587			break;
5588		}
5589
5590		ret = btrfs_issue_discard(device->bdev, start, len,
5591					  &bytes);
5592		if (!ret)
5593			set_extent_bits(&device->alloc_state, start,
5594					start + bytes - 1,
5595					CHUNK_TRIMMED);
5596		mutex_unlock(&fs_info->chunk_mutex);
5597
5598		if (ret)
5599			break;
5600
5601		start += len;
5602		*trimmed += bytes;
5603
5604		if (fatal_signal_pending(current)) {
5605			ret = -ERESTARTSYS;
5606			break;
5607		}
5608
5609		cond_resched();
5610	}
5611
5612	return ret;
5613}
5614
5615/*
5616 * Trim the whole filesystem by:
5617 * 1) trimming the free space in each block group
5618 * 2) trimming the unallocated space on each device
5619 *
5620 * This will also continue trimming even if a block group or device encounters
5621 * an error.  The return value will be the last error, or 0 if nothing bad
5622 * happens.
5623 */
5624int btrfs_trim_fs(struct btrfs_fs_info *fs_info, struct fstrim_range *range)
5625{
5626	struct btrfs_block_group_cache *cache = NULL;
 
5627	struct btrfs_device *device;
5628	struct list_head *devices;
5629	u64 group_trimmed;
5630	u64 range_end = U64_MAX;
5631	u64 start;
5632	u64 end;
5633	u64 trimmed = 0;
5634	u64 bg_failed = 0;
5635	u64 dev_failed = 0;
5636	int bg_ret = 0;
5637	int dev_ret = 0;
5638	int ret = 0;
5639
 
 
 
5640	/*
5641	 * Check range overflow if range->len is set.
5642	 * The default range->len is U64_MAX.
5643	 */
5644	if (range->len != U64_MAX &&
5645	    check_add_overflow(range->start, range->len, &range_end))
5646		return -EINVAL;
5647
5648	cache = btrfs_lookup_first_block_group(fs_info, range->start);
5649	for (; cache; cache = btrfs_next_block_group(cache)) {
5650		if (cache->key.objectid >= range_end) {
5651			btrfs_put_block_group(cache);
5652			break;
5653		}
5654
5655		start = max(range->start, cache->key.objectid);
5656		end = min(range_end, cache->key.objectid + cache->key.offset);
5657
5658		if (end - start >= range->minlen) {
5659			if (!btrfs_block_group_cache_done(cache)) {
5660				ret = btrfs_cache_block_group(cache, 0);
5661				if (ret) {
5662					bg_failed++;
5663					bg_ret = ret;
5664					continue;
5665				}
5666				ret = btrfs_wait_block_group_cache_done(cache);
5667				if (ret) {
5668					bg_failed++;
5669					bg_ret = ret;
5670					continue;
5671				}
5672			}
5673			ret = btrfs_trim_block_group(cache,
5674						     &group_trimmed,
5675						     start,
5676						     end,
5677						     range->minlen);
5678
5679			trimmed += group_trimmed;
5680			if (ret) {
5681				bg_failed++;
5682				bg_ret = ret;
5683				continue;
5684			}
5685		}
5686	}
5687
5688	if (bg_failed)
5689		btrfs_warn(fs_info,
5690			"failed to trim %llu block group(s), last error %d",
5691			bg_failed, bg_ret);
5692	mutex_lock(&fs_info->fs_devices->device_list_mutex);
5693	devices = &fs_info->fs_devices->devices;
5694	list_for_each_entry(device, devices, dev_list) {
 
 
 
5695		ret = btrfs_trim_free_extents(device, &group_trimmed);
5696		if (ret) {
5697			dev_failed++;
5698			dev_ret = ret;
5699			break;
5700		}
5701
5702		trimmed += group_trimmed;
5703	}
5704	mutex_unlock(&fs_info->fs_devices->device_list_mutex);
5705
5706	if (dev_failed)
5707		btrfs_warn(fs_info,
5708			"failed to trim %llu device(s), last error %d",
5709			dev_failed, dev_ret);
5710	range->len = trimmed;
5711	if (bg_ret)
5712		return bg_ret;
5713	return dev_ret;
5714}
5715
5716/*
5717 * btrfs_{start,end}_write_no_snapshotting() are similar to
5718 * mnt_{want,drop}_write(), they are used to prevent some tasks from writing
5719 * data into the page cache through nocow before the subvolume is snapshoted,
5720 * but flush the data into disk after the snapshot creation, or to prevent
5721 * operations while snapshotting is ongoing and that cause the snapshot to be
5722 * inconsistent (writes followed by expanding truncates for example).
5723 */
5724void btrfs_end_write_no_snapshotting(struct btrfs_root *root)
5725{
5726	percpu_counter_dec(&root->subv_writers->counter);
5727	cond_wake_up(&root->subv_writers->wait);
5728}
5729
5730int btrfs_start_write_no_snapshotting(struct btrfs_root *root)
5731{
5732	if (atomic_read(&root->will_be_snapshotted))
5733		return 0;
5734
5735	percpu_counter_inc(&root->subv_writers->counter);
5736	/*
5737	 * Make sure counter is updated before we check for snapshot creation.
5738	 */
5739	smp_mb();
5740	if (atomic_read(&root->will_be_snapshotted)) {
5741		btrfs_end_write_no_snapshotting(root);
5742		return 0;
5743	}
5744	return 1;
5745}
5746
5747void btrfs_wait_for_snapshot_creation(struct btrfs_root *root)
5748{
5749	while (true) {
5750		int ret;
5751
5752		ret = btrfs_start_write_no_snapshotting(root);
5753		if (ret)
5754			break;
5755		wait_var_event(&root->will_be_snapshotted,
5756			       !atomic_read(&root->will_be_snapshotted));
5757	}
5758}