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 "ctree.h"
  20#include "extent-tree.h"
  21#include "transaction.h"
  22#include "disk-io.h"
  23#include "print-tree.h"
  24#include "volumes.h"
  25#include "raid56.h"
  26#include "locking.h"
  27#include "free-space-cache.h"
  28#include "free-space-tree.h"
  29#include "qgroup.h"
  30#include "ref-verify.h"
  31#include "space-info.h"
  32#include "block-rsv.h"
  33#include "discard.h"
  34#include "zoned.h"
  35#include "dev-replace.h"
  36#include "fs.h"
  37#include "accessors.h"
  38#include "root-tree.h"
  39#include "file-item.h"
  40#include "orphan.h"
  41#include "tree-checker.h"
  42#include "raid-stripe-tree.h"
  43
  44#undef SCRAMBLE_DELAYED_REFS
  45
  46
  47static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
  48			       struct btrfs_delayed_ref_head *href,
  49			       struct btrfs_delayed_ref_node *node, u64 parent,
  50			       u64 root_objectid, u64 owner_objectid,
  51			       u64 owner_offset,
  52			       struct btrfs_delayed_extent_op *extra_op);
  53static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
  54				    struct extent_buffer *leaf,
  55				    struct btrfs_extent_item *ei);
  56static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
  57				      u64 parent, u64 root_objectid,
  58				      u64 flags, u64 owner, u64 offset,
  59				      struct btrfs_key *ins, int ref_mod, u64 oref_root);
  60static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
  61				     struct btrfs_delayed_ref_node *node,
  62				     struct btrfs_delayed_extent_op *extent_op);
  63static int find_next_key(struct btrfs_path *path, int level,
  64			 struct btrfs_key *key);
  65
  66static int block_group_bits(struct btrfs_block_group *cache, u64 bits)
  67{
  68	return (cache->flags & bits) == bits;
  69}
  70
  71/* simple helper to search for an existing data extent at a given offset */
  72int btrfs_lookup_data_extent(struct btrfs_fs_info *fs_info, u64 start, u64 len)
  73{
  74	struct btrfs_root *root = btrfs_extent_root(fs_info, start);
  75	int ret;
  76	struct btrfs_key key;
  77	struct btrfs_path *path;
  78
  79	path = btrfs_alloc_path();
  80	if (!path)
  81		return -ENOMEM;
  82
  83	key.objectid = start;
  84	key.offset = len;
  85	key.type = BTRFS_EXTENT_ITEM_KEY;
  86	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
  87	btrfs_free_path(path);
  88	return ret;
  89}
  90
  91/*
  92 * helper function to lookup reference count and flags of a tree block.
  93 *
  94 * the head node for delayed ref is used to store the sum of all the
  95 * reference count modifications queued up in the rbtree. the head
  96 * node may also store the extent flags to set. This way you can check
  97 * to see what the reference count and extent flags would be if all of
  98 * the delayed refs are not processed.
  99 */
 100int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans,
 101			     struct btrfs_fs_info *fs_info, u64 bytenr,
 102			     u64 offset, int metadata, u64 *refs, u64 *flags,
 103			     u64 *owning_root)
 104{
 105	struct btrfs_root *extent_root;
 106	struct btrfs_delayed_ref_head *head;
 107	struct btrfs_delayed_ref_root *delayed_refs;
 108	struct btrfs_path *path;
 109	struct btrfs_extent_item *ei;
 110	struct extent_buffer *leaf;
 111	struct btrfs_key key;
 112	u32 item_size;
 113	u64 num_refs;
 114	u64 extent_flags;
 115	u64 owner = 0;
 116	int ret;
 117
 118	/*
 119	 * If we don't have skinny metadata, don't bother doing anything
 120	 * different
 121	 */
 122	if (metadata && !btrfs_fs_incompat(fs_info, SKINNY_METADATA)) {
 123		offset = fs_info->nodesize;
 124		metadata = 0;
 125	}
 126
 127	path = btrfs_alloc_path();
 128	if (!path)
 129		return -ENOMEM;
 130
 131	if (!trans) {
 132		path->skip_locking = 1;
 133		path->search_commit_root = 1;
 134	}
 135
 136search_again:
 137	key.objectid = bytenr;
 138	key.offset = offset;
 139	if (metadata)
 140		key.type = BTRFS_METADATA_ITEM_KEY;
 141	else
 142		key.type = BTRFS_EXTENT_ITEM_KEY;
 143
 144	extent_root = btrfs_extent_root(fs_info, bytenr);
 145	ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
 146	if (ret < 0)
 147		goto out_free;
 148
 149	if (ret > 0 && metadata && key.type == BTRFS_METADATA_ITEM_KEY) {
 150		if (path->slots[0]) {
 151			path->slots[0]--;
 152			btrfs_item_key_to_cpu(path->nodes[0], &key,
 153					      path->slots[0]);
 154			if (key.objectid == bytenr &&
 155			    key.type == BTRFS_EXTENT_ITEM_KEY &&
 156			    key.offset == fs_info->nodesize)
 157				ret = 0;
 158		}
 159	}
 160
 161	if (ret == 0) {
 162		leaf = path->nodes[0];
 163		item_size = btrfs_item_size(leaf, path->slots[0]);
 164		if (item_size >= sizeof(*ei)) {
 165			ei = btrfs_item_ptr(leaf, path->slots[0],
 166					    struct btrfs_extent_item);
 167			num_refs = btrfs_extent_refs(leaf, ei);
 168			extent_flags = btrfs_extent_flags(leaf, ei);
 169			owner = btrfs_get_extent_owner_root(fs_info, leaf,
 170							    path->slots[0]);
 171		} else {
 172			ret = -EUCLEAN;
 173			btrfs_err(fs_info,
 174			"unexpected extent item size, has %u expect >= %zu",
 175				  item_size, sizeof(*ei));
 176			if (trans)
 177				btrfs_abort_transaction(trans, ret);
 178			else
 179				btrfs_handle_fs_error(fs_info, ret, NULL);
 180
 181			goto out_free;
 182		}
 183
 184		BUG_ON(num_refs == 0);
 
 
 
 
 
 
 
 
 
 
 
 185	} else {
 186		num_refs = 0;
 187		extent_flags = 0;
 188		ret = 0;
 189	}
 190
 191	if (!trans)
 192		goto out;
 193
 194	delayed_refs = &trans->transaction->delayed_refs;
 195	spin_lock(&delayed_refs->lock);
 196	head = btrfs_find_delayed_ref_head(delayed_refs, bytenr);
 197	if (head) {
 198		if (!mutex_trylock(&head->mutex)) {
 199			refcount_inc(&head->refs);
 200			spin_unlock(&delayed_refs->lock);
 201
 202			btrfs_release_path(path);
 203
 204			/*
 205			 * Mutex was contended, block until it's released and try
 206			 * again
 207			 */
 208			mutex_lock(&head->mutex);
 209			mutex_unlock(&head->mutex);
 210			btrfs_put_delayed_ref_head(head);
 211			goto search_again;
 212		}
 213		spin_lock(&head->lock);
 214		if (head->extent_op && head->extent_op->update_flags)
 215			extent_flags |= head->extent_op->flags_to_set;
 216		else
 217			BUG_ON(num_refs == 0);
 218
 219		num_refs += head->ref_mod;
 220		spin_unlock(&head->lock);
 221		mutex_unlock(&head->mutex);
 222	}
 223	spin_unlock(&delayed_refs->lock);
 224out:
 225	WARN_ON(num_refs == 0);
 226	if (refs)
 227		*refs = num_refs;
 228	if (flags)
 229		*flags = extent_flags;
 230	if (owning_root)
 231		*owning_root = owner;
 232out_free:
 233	btrfs_free_path(path);
 234	return ret;
 235}
 236
 237/*
 238 * Back reference rules.  Back refs have three main goals:
 239 *
 240 * 1) differentiate between all holders of references to an extent so that
 241 *    when a reference is dropped we can make sure it was a valid reference
 242 *    before freeing the extent.
 243 *
 244 * 2) Provide enough information to quickly find the holders of an extent
 245 *    if we notice a given block is corrupted or bad.
 246 *
 247 * 3) Make it easy to migrate blocks for FS shrinking or storage pool
 248 *    maintenance.  This is actually the same as #2, but with a slightly
 249 *    different use case.
 250 *
 251 * There are two kinds of back refs. The implicit back refs is optimized
 252 * for pointers in non-shared tree blocks. For a given pointer in a block,
 253 * back refs of this kind provide information about the block's owner tree
 254 * and the pointer's key. These information allow us to find the block by
 255 * b-tree searching. The full back refs is for pointers in tree blocks not
 256 * referenced by their owner trees. The location of tree block is recorded
 257 * in the back refs. Actually the full back refs is generic, and can be
 258 * used in all cases the implicit back refs is used. The major shortcoming
 259 * of the full back refs is its overhead. Every time a tree block gets
 260 * COWed, we have to update back refs entry for all pointers in it.
 261 *
 262 * For a newly allocated tree block, we use implicit back refs for
 263 * pointers in it. This means most tree related operations only involve
 264 * implicit back refs. For a tree block created in old transaction, the
 265 * only way to drop a reference to it is COW it. So we can detect the
 266 * event that tree block loses its owner tree's reference and do the
 267 * back refs conversion.
 268 *
 269 * When a tree block is COWed through a tree, there are four cases:
 270 *
 271 * The reference count of the block is one and the tree is the block's
 272 * owner tree. Nothing to do in this case.
 273 *
 274 * The reference count of the block is one and the tree is not the
 275 * block's owner tree. In this case, full back refs is used for pointers
 276 * in the block. Remove these full back refs, add implicit back refs for
 277 * every pointers in the new block.
 278 *
 279 * The reference count of the block is greater than one and the tree is
 280 * the block's owner tree. In this case, implicit back refs is used for
 281 * pointers in the block. Add full back refs for every pointers in the
 282 * block, increase lower level extents' reference counts. The original
 283 * implicit back refs are entailed to the new block.
 284 *
 285 * The reference count of the block is greater than one and the tree is
 286 * not the block's owner tree. Add implicit back refs for every pointer in
 287 * the new block, increase lower level extents' reference count.
 288 *
 289 * Back Reference Key composing:
 290 *
 291 * The key objectid corresponds to the first byte in the extent,
 292 * The key type is used to differentiate between types of back refs.
 293 * There are different meanings of the key offset for different types
 294 * of back refs.
 295 *
 296 * File extents can be referenced by:
 297 *
 298 * - multiple snapshots, subvolumes, or different generations in one subvol
 299 * - different files inside a single subvolume
 300 * - different offsets inside a file (bookend extents in file.c)
 301 *
 302 * The extent ref structure for the implicit back refs has fields for:
 303 *
 304 * - Objectid of the subvolume root
 305 * - objectid of the file holding the reference
 306 * - original offset in the file
 307 * - how many bookend extents
 308 *
 309 * The key offset for the implicit back refs is hash of the first
 310 * three fields.
 311 *
 312 * The extent ref structure for the full back refs has field for:
 313 *
 314 * - number of pointers in the tree leaf
 315 *
 316 * The key offset for the implicit back refs is the first byte of
 317 * the tree leaf
 318 *
 319 * When a file extent is allocated, The implicit back refs is used.
 320 * the fields are filled in:
 321 *
 322 *     (root_key.objectid, inode objectid, offset in file, 1)
 323 *
 324 * When a file extent is removed file truncation, we find the
 325 * corresponding implicit back refs and check the following fields:
 326 *
 327 *     (btrfs_header_owner(leaf), inode objectid, offset in file)
 328 *
 329 * Btree extents can be referenced by:
 330 *
 331 * - Different subvolumes
 332 *
 333 * Both the implicit back refs and the full back refs for tree blocks
 334 * only consist of key. The key offset for the implicit back refs is
 335 * objectid of block's owner tree. The key offset for the full back refs
 336 * is the first byte of parent block.
 337 *
 338 * When implicit back refs is used, information about the lowest key and
 339 * level of the tree block are required. These information are stored in
 340 * tree block info structure.
 341 */
 342
 343/*
 344 * is_data == BTRFS_REF_TYPE_BLOCK, tree block type is required,
 345 * is_data == BTRFS_REF_TYPE_DATA, data type is requiried,
 346 * is_data == BTRFS_REF_TYPE_ANY, either type is OK.
 347 */
 348int btrfs_get_extent_inline_ref_type(const struct extent_buffer *eb,
 349				     struct btrfs_extent_inline_ref *iref,
 350				     enum btrfs_inline_ref_type is_data)
 351{
 352	struct btrfs_fs_info *fs_info = eb->fs_info;
 353	int type = btrfs_extent_inline_ref_type(eb, iref);
 354	u64 offset = btrfs_extent_inline_ref_offset(eb, iref);
 355
 356	if (type == BTRFS_EXTENT_OWNER_REF_KEY) {
 357		ASSERT(btrfs_fs_incompat(fs_info, SIMPLE_QUOTA));
 358		return type;
 359	}
 360
 361	if (type == BTRFS_TREE_BLOCK_REF_KEY ||
 362	    type == BTRFS_SHARED_BLOCK_REF_KEY ||
 363	    type == BTRFS_SHARED_DATA_REF_KEY ||
 364	    type == BTRFS_EXTENT_DATA_REF_KEY) {
 365		if (is_data == BTRFS_REF_TYPE_BLOCK) {
 366			if (type == BTRFS_TREE_BLOCK_REF_KEY)
 367				return type;
 368			if (type == BTRFS_SHARED_BLOCK_REF_KEY) {
 369				ASSERT(fs_info);
 370				/*
 371				 * Every shared one has parent tree block,
 372				 * which must be aligned to sector size.
 373				 */
 374				if (offset && IS_ALIGNED(offset, fs_info->sectorsize))
 375					return type;
 376			}
 377		} else if (is_data == BTRFS_REF_TYPE_DATA) {
 378			if (type == BTRFS_EXTENT_DATA_REF_KEY)
 379				return type;
 380			if (type == BTRFS_SHARED_DATA_REF_KEY) {
 381				ASSERT(fs_info);
 382				/*
 383				 * Every shared one has parent tree block,
 384				 * which must be aligned to sector size.
 385				 */
 386				if (offset &&
 387				    IS_ALIGNED(offset, fs_info->sectorsize))
 388					return type;
 389			}
 390		} else {
 391			ASSERT(is_data == BTRFS_REF_TYPE_ANY);
 392			return type;
 393		}
 394	}
 395
 396	WARN_ON(1);
 397	btrfs_print_leaf(eb);
 398	btrfs_err(fs_info,
 399		  "eb %llu iref 0x%lx invalid extent inline ref type %d",
 400		  eb->start, (unsigned long)iref, type);
 401
 402	return BTRFS_REF_TYPE_INVALID;
 403}
 404
 405u64 hash_extent_data_ref(u64 root_objectid, u64 owner, u64 offset)
 406{
 407	u32 high_crc = ~(u32)0;
 408	u32 low_crc = ~(u32)0;
 409	__le64 lenum;
 410
 411	lenum = cpu_to_le64(root_objectid);
 412	high_crc = crc32c(high_crc, &lenum, sizeof(lenum));
 413	lenum = cpu_to_le64(owner);
 414	low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
 415	lenum = cpu_to_le64(offset);
 416	low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
 417
 418	return ((u64)high_crc << 31) ^ (u64)low_crc;
 419}
 420
 421static u64 hash_extent_data_ref_item(struct extent_buffer *leaf,
 422				     struct btrfs_extent_data_ref *ref)
 423{
 424	return hash_extent_data_ref(btrfs_extent_data_ref_root(leaf, ref),
 425				    btrfs_extent_data_ref_objectid(leaf, ref),
 426				    btrfs_extent_data_ref_offset(leaf, ref));
 427}
 428
 429static int match_extent_data_ref(struct extent_buffer *leaf,
 430				 struct btrfs_extent_data_ref *ref,
 431				 u64 root_objectid, u64 owner, u64 offset)
 432{
 433	if (btrfs_extent_data_ref_root(leaf, ref) != root_objectid ||
 434	    btrfs_extent_data_ref_objectid(leaf, ref) != owner ||
 435	    btrfs_extent_data_ref_offset(leaf, ref) != offset)
 436		return 0;
 437	return 1;
 438}
 439
 440static noinline int lookup_extent_data_ref(struct btrfs_trans_handle *trans,
 441					   struct btrfs_path *path,
 442					   u64 bytenr, u64 parent,
 443					   u64 root_objectid,
 444					   u64 owner, u64 offset)
 445{
 446	struct btrfs_root *root = btrfs_extent_root(trans->fs_info, bytenr);
 447	struct btrfs_key key;
 448	struct btrfs_extent_data_ref *ref;
 449	struct extent_buffer *leaf;
 450	u32 nritems;
 451	int ret;
 452	int recow;
 453	int err = -ENOENT;
 454
 455	key.objectid = bytenr;
 456	if (parent) {
 457		key.type = BTRFS_SHARED_DATA_REF_KEY;
 458		key.offset = parent;
 459	} else {
 460		key.type = BTRFS_EXTENT_DATA_REF_KEY;
 461		key.offset = hash_extent_data_ref(root_objectid,
 462						  owner, offset);
 463	}
 464again:
 465	recow = 0;
 466	ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
 467	if (ret < 0) {
 468		err = ret;
 469		goto fail;
 470	}
 471
 472	if (parent) {
 473		if (!ret)
 474			return 0;
 475		goto fail;
 476	}
 477
 
 478	leaf = path->nodes[0];
 479	nritems = btrfs_header_nritems(leaf);
 480	while (1) {
 481		if (path->slots[0] >= nritems) {
 482			ret = btrfs_next_leaf(root, path);
 483			if (ret < 0)
 484				err = ret;
 485			if (ret)
 486				goto fail;
 
 487
 488			leaf = path->nodes[0];
 489			nritems = btrfs_header_nritems(leaf);
 490			recow = 1;
 491		}
 492
 493		btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 494		if (key.objectid != bytenr ||
 495		    key.type != BTRFS_EXTENT_DATA_REF_KEY)
 496			goto fail;
 497
 498		ref = btrfs_item_ptr(leaf, path->slots[0],
 499				     struct btrfs_extent_data_ref);
 500
 501		if (match_extent_data_ref(leaf, ref, root_objectid,
 502					  owner, offset)) {
 503			if (recow) {
 504				btrfs_release_path(path);
 505				goto again;
 506			}
 507			err = 0;
 508			break;
 509		}
 510		path->slots[0]++;
 511	}
 512fail:
 513	return err;
 514}
 515
 516static noinline int insert_extent_data_ref(struct btrfs_trans_handle *trans,
 517					   struct btrfs_path *path,
 518					   u64 bytenr, u64 parent,
 519					   u64 root_objectid, u64 owner,
 520					   u64 offset, int refs_to_add)
 521{
 522	struct btrfs_root *root = btrfs_extent_root(trans->fs_info, bytenr);
 523	struct btrfs_key key;
 524	struct extent_buffer *leaf;
 
 
 525	u32 size;
 526	u32 num_refs;
 527	int ret;
 528
 529	key.objectid = bytenr;
 530	if (parent) {
 531		key.type = BTRFS_SHARED_DATA_REF_KEY;
 532		key.offset = parent;
 533		size = sizeof(struct btrfs_shared_data_ref);
 534	} else {
 535		key.type = BTRFS_EXTENT_DATA_REF_KEY;
 536		key.offset = hash_extent_data_ref(root_objectid,
 537						  owner, offset);
 538		size = sizeof(struct btrfs_extent_data_ref);
 539	}
 540
 541	ret = btrfs_insert_empty_item(trans, root, path, &key, size);
 542	if (ret && ret != -EEXIST)
 543		goto fail;
 544
 545	leaf = path->nodes[0];
 546	if (parent) {
 547		struct btrfs_shared_data_ref *ref;
 548		ref = btrfs_item_ptr(leaf, path->slots[0],
 549				     struct btrfs_shared_data_ref);
 550		if (ret == 0) {
 551			btrfs_set_shared_data_ref_count(leaf, ref, refs_to_add);
 552		} else {
 553			num_refs = btrfs_shared_data_ref_count(leaf, ref);
 554			num_refs += refs_to_add;
 555			btrfs_set_shared_data_ref_count(leaf, ref, num_refs);
 556		}
 557	} else {
 558		struct btrfs_extent_data_ref *ref;
 559		while (ret == -EEXIST) {
 560			ref = btrfs_item_ptr(leaf, path->slots[0],
 561					     struct btrfs_extent_data_ref);
 562			if (match_extent_data_ref(leaf, ref, root_objectid,
 563						  owner, offset))
 564				break;
 565			btrfs_release_path(path);
 566			key.offset++;
 567			ret = btrfs_insert_empty_item(trans, root, path, &key,
 568						      size);
 569			if (ret && ret != -EEXIST)
 570				goto fail;
 571
 572			leaf = path->nodes[0];
 573		}
 574		ref = btrfs_item_ptr(leaf, path->slots[0],
 575				     struct btrfs_extent_data_ref);
 576		if (ret == 0) {
 577			btrfs_set_extent_data_ref_root(leaf, ref,
 578						       root_objectid);
 579			btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
 580			btrfs_set_extent_data_ref_offset(leaf, ref, offset);
 581			btrfs_set_extent_data_ref_count(leaf, ref, refs_to_add);
 582		} else {
 583			num_refs = btrfs_extent_data_ref_count(leaf, ref);
 584			num_refs += refs_to_add;
 585			btrfs_set_extent_data_ref_count(leaf, ref, num_refs);
 586		}
 587	}
 588	btrfs_mark_buffer_dirty(trans, leaf);
 589	ret = 0;
 590fail:
 591	btrfs_release_path(path);
 592	return ret;
 593}
 594
 595static noinline int remove_extent_data_ref(struct btrfs_trans_handle *trans,
 596					   struct btrfs_root *root,
 597					   struct btrfs_path *path,
 598					   int refs_to_drop)
 599{
 600	struct btrfs_key key;
 601	struct btrfs_extent_data_ref *ref1 = NULL;
 602	struct btrfs_shared_data_ref *ref2 = NULL;
 603	struct extent_buffer *leaf;
 604	u32 num_refs = 0;
 605	int ret = 0;
 606
 607	leaf = path->nodes[0];
 608	btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 609
 610	if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
 611		ref1 = btrfs_item_ptr(leaf, path->slots[0],
 612				      struct btrfs_extent_data_ref);
 613		num_refs = btrfs_extent_data_ref_count(leaf, ref1);
 614	} else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
 615		ref2 = btrfs_item_ptr(leaf, path->slots[0],
 616				      struct btrfs_shared_data_ref);
 617		num_refs = btrfs_shared_data_ref_count(leaf, ref2);
 618	} else {
 619		btrfs_err(trans->fs_info,
 620			  "unrecognized backref key (%llu %u %llu)",
 621			  key.objectid, key.type, key.offset);
 622		btrfs_abort_transaction(trans, -EUCLEAN);
 623		return -EUCLEAN;
 624	}
 625
 626	BUG_ON(num_refs < refs_to_drop);
 627	num_refs -= refs_to_drop;
 628
 629	if (num_refs == 0) {
 630		ret = btrfs_del_item(trans, root, path);
 631	} else {
 632		if (key.type == BTRFS_EXTENT_DATA_REF_KEY)
 633			btrfs_set_extent_data_ref_count(leaf, ref1, num_refs);
 634		else if (key.type == BTRFS_SHARED_DATA_REF_KEY)
 635			btrfs_set_shared_data_ref_count(leaf, ref2, num_refs);
 636		btrfs_mark_buffer_dirty(trans, leaf);
 637	}
 638	return ret;
 639}
 640
 641static noinline u32 extent_data_ref_count(struct btrfs_path *path,
 642					  struct btrfs_extent_inline_ref *iref)
 643{
 644	struct btrfs_key key;
 645	struct extent_buffer *leaf;
 646	struct btrfs_extent_data_ref *ref1;
 647	struct btrfs_shared_data_ref *ref2;
 648	u32 num_refs = 0;
 649	int type;
 650
 651	leaf = path->nodes[0];
 652	btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 653
 654	if (iref) {
 655		/*
 656		 * If type is invalid, we should have bailed out earlier than
 657		 * this call.
 658		 */
 659		type = btrfs_get_extent_inline_ref_type(leaf, iref, BTRFS_REF_TYPE_DATA);
 660		ASSERT(type != BTRFS_REF_TYPE_INVALID);
 661		if (type == BTRFS_EXTENT_DATA_REF_KEY) {
 662			ref1 = (struct btrfs_extent_data_ref *)(&iref->offset);
 663			num_refs = btrfs_extent_data_ref_count(leaf, ref1);
 664		} else {
 665			ref2 = (struct btrfs_shared_data_ref *)(iref + 1);
 666			num_refs = btrfs_shared_data_ref_count(leaf, ref2);
 667		}
 668	} else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
 669		ref1 = btrfs_item_ptr(leaf, path->slots[0],
 670				      struct btrfs_extent_data_ref);
 671		num_refs = btrfs_extent_data_ref_count(leaf, ref1);
 672	} else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
 673		ref2 = btrfs_item_ptr(leaf, path->slots[0],
 674				      struct btrfs_shared_data_ref);
 675		num_refs = btrfs_shared_data_ref_count(leaf, ref2);
 676	} else {
 677		WARN_ON(1);
 678	}
 679	return num_refs;
 680}
 681
 682static noinline int lookup_tree_block_ref(struct btrfs_trans_handle *trans,
 683					  struct btrfs_path *path,
 684					  u64 bytenr, u64 parent,
 685					  u64 root_objectid)
 686{
 687	struct btrfs_root *root = btrfs_extent_root(trans->fs_info, bytenr);
 688	struct btrfs_key key;
 689	int ret;
 690
 691	key.objectid = bytenr;
 692	if (parent) {
 693		key.type = BTRFS_SHARED_BLOCK_REF_KEY;
 694		key.offset = parent;
 695	} else {
 696		key.type = BTRFS_TREE_BLOCK_REF_KEY;
 697		key.offset = root_objectid;
 698	}
 699
 700	ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
 701	if (ret > 0)
 702		ret = -ENOENT;
 703	return ret;
 704}
 705
 706static noinline int insert_tree_block_ref(struct btrfs_trans_handle *trans,
 707					  struct btrfs_path *path,
 708					  u64 bytenr, u64 parent,
 709					  u64 root_objectid)
 710{
 711	struct btrfs_root *root = btrfs_extent_root(trans->fs_info, bytenr);
 712	struct btrfs_key key;
 713	int ret;
 714
 715	key.objectid = bytenr;
 716	if (parent) {
 717		key.type = BTRFS_SHARED_BLOCK_REF_KEY;
 718		key.offset = parent;
 719	} else {
 720		key.type = BTRFS_TREE_BLOCK_REF_KEY;
 721		key.offset = root_objectid;
 722	}
 723
 724	ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
 725	btrfs_release_path(path);
 726	return ret;
 727}
 728
 729static inline int extent_ref_type(u64 parent, u64 owner)
 730{
 731	int type;
 732	if (owner < BTRFS_FIRST_FREE_OBJECTID) {
 733		if (parent > 0)
 734			type = BTRFS_SHARED_BLOCK_REF_KEY;
 735		else
 736			type = BTRFS_TREE_BLOCK_REF_KEY;
 737	} else {
 738		if (parent > 0)
 739			type = BTRFS_SHARED_DATA_REF_KEY;
 740		else
 741			type = BTRFS_EXTENT_DATA_REF_KEY;
 742	}
 743	return type;
 744}
 745
 746static int find_next_key(struct btrfs_path *path, int level,
 747			 struct btrfs_key *key)
 748
 749{
 750	for (; level < BTRFS_MAX_LEVEL; level++) {
 751		if (!path->nodes[level])
 752			break;
 753		if (path->slots[level] + 1 >=
 754		    btrfs_header_nritems(path->nodes[level]))
 755			continue;
 756		if (level == 0)
 757			btrfs_item_key_to_cpu(path->nodes[level], key,
 758					      path->slots[level] + 1);
 759		else
 760			btrfs_node_key_to_cpu(path->nodes[level], key,
 761					      path->slots[level] + 1);
 762		return 0;
 763	}
 764	return 1;
 765}
 766
 767/*
 768 * look for inline back ref. if back ref is found, *ref_ret is set
 769 * to the address of inline back ref, and 0 is returned.
 770 *
 771 * if back ref isn't found, *ref_ret is set to the address where it
 772 * should be inserted, and -ENOENT is returned.
 773 *
 774 * if insert is true and there are too many inline back refs, the path
 775 * points to the extent item, and -EAGAIN is returned.
 776 *
 777 * NOTE: inline back refs are ordered in the same way that back ref
 778 *	 items in the tree are ordered.
 779 */
 780static noinline_for_stack
 781int lookup_inline_extent_backref(struct btrfs_trans_handle *trans,
 782				 struct btrfs_path *path,
 783				 struct btrfs_extent_inline_ref **ref_ret,
 784				 u64 bytenr, u64 num_bytes,
 785				 u64 parent, u64 root_objectid,
 786				 u64 owner, u64 offset, int insert)
 787{
 788	struct btrfs_fs_info *fs_info = trans->fs_info;
 789	struct btrfs_root *root = btrfs_extent_root(fs_info, bytenr);
 790	struct btrfs_key key;
 791	struct extent_buffer *leaf;
 792	struct btrfs_extent_item *ei;
 793	struct btrfs_extent_inline_ref *iref;
 794	u64 flags;
 795	u64 item_size;
 796	unsigned long ptr;
 797	unsigned long end;
 798	int extra_size;
 799	int type;
 800	int want;
 801	int ret;
 802	bool skinny_metadata = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
 803	int needed;
 804
 805	key.objectid = bytenr;
 806	key.type = BTRFS_EXTENT_ITEM_KEY;
 807	key.offset = num_bytes;
 808
 809	want = extent_ref_type(parent, owner);
 810	if (insert) {
 811		extra_size = btrfs_extent_inline_ref_size(want);
 812		path->search_for_extension = 1;
 813		path->keep_locks = 1;
 814	} else
 815		extra_size = -1;
 816
 817	/*
 818	 * Owner is our level, so we can just add one to get the level for the
 819	 * block we are interested in.
 820	 */
 821	if (skinny_metadata && owner < BTRFS_FIRST_FREE_OBJECTID) {
 822		key.type = BTRFS_METADATA_ITEM_KEY;
 823		key.offset = owner;
 824	}
 825
 826again:
 827	ret = btrfs_search_slot(trans, root, &key, path, extra_size, 1);
 828	if (ret < 0)
 829		goto out;
 830
 831	/*
 832	 * We may be a newly converted file system which still has the old fat
 833	 * extent entries for metadata, so try and see if we have one of those.
 834	 */
 835	if (ret > 0 && skinny_metadata) {
 836		skinny_metadata = false;
 837		if (path->slots[0]) {
 838			path->slots[0]--;
 839			btrfs_item_key_to_cpu(path->nodes[0], &key,
 840					      path->slots[0]);
 841			if (key.objectid == bytenr &&
 842			    key.type == BTRFS_EXTENT_ITEM_KEY &&
 843			    key.offset == num_bytes)
 844				ret = 0;
 845		}
 846		if (ret) {
 847			key.objectid = bytenr;
 848			key.type = BTRFS_EXTENT_ITEM_KEY;
 849			key.offset = num_bytes;
 850			btrfs_release_path(path);
 851			goto again;
 852		}
 853	}
 854
 855	if (ret && !insert) {
 856		ret = -ENOENT;
 857		goto out;
 858	} else if (WARN_ON(ret)) {
 859		btrfs_print_leaf(path->nodes[0]);
 860		btrfs_err(fs_info,
 861"extent item not found for insert, bytenr %llu num_bytes %llu parent %llu root_objectid %llu owner %llu offset %llu",
 862			  bytenr, num_bytes, parent, root_objectid, owner,
 863			  offset);
 864		ret = -EUCLEAN;
 865		goto out;
 866	}
 867
 868	leaf = path->nodes[0];
 869	item_size = btrfs_item_size(leaf, path->slots[0]);
 870	if (unlikely(item_size < sizeof(*ei))) {
 871		ret = -EUCLEAN;
 872		btrfs_err(fs_info,
 873			  "unexpected extent item size, has %llu expect >= %zu",
 874			  item_size, sizeof(*ei));
 875		btrfs_abort_transaction(trans, ret);
 876		goto out;
 877	}
 878
 879	ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
 880	flags = btrfs_extent_flags(leaf, ei);
 881
 882	ptr = (unsigned long)(ei + 1);
 883	end = (unsigned long)ei + item_size;
 884
 885	if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK && !skinny_metadata) {
 886		ptr += sizeof(struct btrfs_tree_block_info);
 887		BUG_ON(ptr > end);
 888	}
 889
 890	if (owner >= BTRFS_FIRST_FREE_OBJECTID)
 891		needed = BTRFS_REF_TYPE_DATA;
 892	else
 893		needed = BTRFS_REF_TYPE_BLOCK;
 894
 895	ret = -ENOENT;
 896	while (ptr < end) {
 897		iref = (struct btrfs_extent_inline_ref *)ptr;
 898		type = btrfs_get_extent_inline_ref_type(leaf, iref, needed);
 899		if (type == BTRFS_EXTENT_OWNER_REF_KEY) {
 900			ASSERT(btrfs_fs_incompat(fs_info, SIMPLE_QUOTA));
 901			ptr += btrfs_extent_inline_ref_size(type);
 902			continue;
 903		}
 904		if (type == BTRFS_REF_TYPE_INVALID) {
 905			ret = -EUCLEAN;
 906			goto out;
 907		}
 908
 909		if (want < type)
 910			break;
 911		if (want > type) {
 912			ptr += btrfs_extent_inline_ref_size(type);
 913			continue;
 914		}
 915
 916		if (type == BTRFS_EXTENT_DATA_REF_KEY) {
 917			struct btrfs_extent_data_ref *dref;
 918			dref = (struct btrfs_extent_data_ref *)(&iref->offset);
 919			if (match_extent_data_ref(leaf, dref, root_objectid,
 920						  owner, offset)) {
 921				ret = 0;
 922				break;
 923			}
 924			if (hash_extent_data_ref_item(leaf, dref) <
 925			    hash_extent_data_ref(root_objectid, owner, offset))
 926				break;
 927		} else {
 928			u64 ref_offset;
 929			ref_offset = btrfs_extent_inline_ref_offset(leaf, iref);
 930			if (parent > 0) {
 931				if (parent == ref_offset) {
 932					ret = 0;
 933					break;
 934				}
 935				if (ref_offset < parent)
 936					break;
 937			} else {
 938				if (root_objectid == ref_offset) {
 939					ret = 0;
 940					break;
 941				}
 942				if (ref_offset < root_objectid)
 943					break;
 944			}
 945		}
 946		ptr += btrfs_extent_inline_ref_size(type);
 947	}
 948
 949	if (unlikely(ptr > end)) {
 950		ret = -EUCLEAN;
 951		btrfs_print_leaf(path->nodes[0]);
 952		btrfs_crit(fs_info,
 953"overrun extent record at slot %d while looking for inline extent for root %llu owner %llu offset %llu parent %llu",
 954			   path->slots[0], root_objectid, owner, offset, parent);
 955		goto out;
 956	}
 957
 958	if (ret == -ENOENT && insert) {
 959		if (item_size + extra_size >=
 960		    BTRFS_MAX_EXTENT_ITEM_SIZE(root)) {
 961			ret = -EAGAIN;
 962			goto out;
 963		}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 964		/*
 965		 * To add new inline back ref, we have to make sure
 966		 * there is no corresponding back ref item.
 967		 * For simplicity, we just do not add new inline back
 968		 * ref if there is any kind of item for this block
 969		 */
 970		if (find_next_key(path, 0, &key) == 0 &&
 971		    key.objectid == bytenr &&
 972		    key.type < BTRFS_BLOCK_GROUP_ITEM_KEY) {
 973			ret = -EAGAIN;
 974			goto out;
 975		}
 976	}
 
 977	*ref_ret = (struct btrfs_extent_inline_ref *)ptr;
 978out:
 979	if (insert) {
 980		path->keep_locks = 0;
 981		path->search_for_extension = 0;
 982		btrfs_unlock_up_safe(path, 1);
 983	}
 
 
 984	return ret;
 985}
 986
 987/*
 988 * helper to add new inline back ref
 989 */
 990static noinline_for_stack
 991void setup_inline_extent_backref(struct btrfs_trans_handle *trans,
 992				 struct btrfs_path *path,
 993				 struct btrfs_extent_inline_ref *iref,
 994				 u64 parent, u64 root_objectid,
 995				 u64 owner, u64 offset, int refs_to_add,
 996				 struct btrfs_delayed_extent_op *extent_op)
 997{
 998	struct extent_buffer *leaf;
 999	struct btrfs_extent_item *ei;
1000	unsigned long ptr;
1001	unsigned long end;
1002	unsigned long item_offset;
1003	u64 refs;
1004	int size;
1005	int type;
1006
1007	leaf = path->nodes[0];
1008	ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1009	item_offset = (unsigned long)iref - (unsigned long)ei;
1010
1011	type = extent_ref_type(parent, owner);
1012	size = btrfs_extent_inline_ref_size(type);
1013
1014	btrfs_extend_item(trans, path, size);
1015
1016	ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1017	refs = btrfs_extent_refs(leaf, ei);
1018	refs += refs_to_add;
1019	btrfs_set_extent_refs(leaf, ei, refs);
1020	if (extent_op)
1021		__run_delayed_extent_op(extent_op, leaf, ei);
1022
1023	ptr = (unsigned long)ei + item_offset;
1024	end = (unsigned long)ei + btrfs_item_size(leaf, path->slots[0]);
1025	if (ptr < end - size)
1026		memmove_extent_buffer(leaf, ptr + size, ptr,
1027				      end - size - ptr);
1028
1029	iref = (struct btrfs_extent_inline_ref *)ptr;
1030	btrfs_set_extent_inline_ref_type(leaf, iref, type);
1031	if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1032		struct btrfs_extent_data_ref *dref;
1033		dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1034		btrfs_set_extent_data_ref_root(leaf, dref, root_objectid);
1035		btrfs_set_extent_data_ref_objectid(leaf, dref, owner);
1036		btrfs_set_extent_data_ref_offset(leaf, dref, offset);
1037		btrfs_set_extent_data_ref_count(leaf, dref, refs_to_add);
1038	} else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1039		struct btrfs_shared_data_ref *sref;
1040		sref = (struct btrfs_shared_data_ref *)(iref + 1);
1041		btrfs_set_shared_data_ref_count(leaf, sref, refs_to_add);
1042		btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1043	} else if (type == BTRFS_SHARED_BLOCK_REF_KEY) {
1044		btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1045	} else {
1046		btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
1047	}
1048	btrfs_mark_buffer_dirty(trans, leaf);
1049}
1050
1051static int lookup_extent_backref(struct btrfs_trans_handle *trans,
1052				 struct btrfs_path *path,
1053				 struct btrfs_extent_inline_ref **ref_ret,
1054				 u64 bytenr, u64 num_bytes, u64 parent,
1055				 u64 root_objectid, u64 owner, u64 offset)
1056{
1057	int ret;
1058
1059	ret = lookup_inline_extent_backref(trans, path, ref_ret, bytenr,
1060					   num_bytes, parent, root_objectid,
1061					   owner, offset, 0);
1062	if (ret != -ENOENT)
1063		return ret;
1064
1065	btrfs_release_path(path);
1066	*ref_ret = NULL;
1067
1068	if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1069		ret = lookup_tree_block_ref(trans, path, bytenr, parent,
1070					    root_objectid);
1071	} else {
1072		ret = lookup_extent_data_ref(trans, path, bytenr, parent,
1073					     root_objectid, owner, offset);
1074	}
1075	return ret;
1076}
1077
1078/*
1079 * helper to update/remove inline back ref
1080 */
1081static noinline_for_stack int update_inline_extent_backref(
1082				  struct btrfs_trans_handle *trans,
1083				  struct btrfs_path *path,
1084				  struct btrfs_extent_inline_ref *iref,
1085				  int refs_to_mod,
1086				  struct btrfs_delayed_extent_op *extent_op)
1087{
1088	struct extent_buffer *leaf = path->nodes[0];
1089	struct btrfs_fs_info *fs_info = leaf->fs_info;
1090	struct btrfs_extent_item *ei;
1091	struct btrfs_extent_data_ref *dref = NULL;
1092	struct btrfs_shared_data_ref *sref = NULL;
1093	unsigned long ptr;
1094	unsigned long end;
1095	u32 item_size;
1096	int size;
1097	int type;
1098	u64 refs;
1099
1100	ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1101	refs = btrfs_extent_refs(leaf, ei);
1102	if (unlikely(refs_to_mod < 0 && refs + refs_to_mod <= 0)) {
1103		struct btrfs_key key;
1104		u32 extent_size;
1105
1106		btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1107		if (key.type == BTRFS_METADATA_ITEM_KEY)
1108			extent_size = fs_info->nodesize;
1109		else
1110			extent_size = key.offset;
1111		btrfs_print_leaf(leaf);
1112		btrfs_err(fs_info,
1113	"invalid refs_to_mod for extent %llu num_bytes %u, has %d expect >= -%llu",
1114			  key.objectid, extent_size, refs_to_mod, refs);
1115		return -EUCLEAN;
1116	}
1117	refs += refs_to_mod;
1118	btrfs_set_extent_refs(leaf, ei, refs);
1119	if (extent_op)
1120		__run_delayed_extent_op(extent_op, leaf, ei);
1121
1122	type = btrfs_get_extent_inline_ref_type(leaf, iref, BTRFS_REF_TYPE_ANY);
1123	/*
1124	 * Function btrfs_get_extent_inline_ref_type() has already printed
1125	 * error messages.
1126	 */
1127	if (unlikely(type == BTRFS_REF_TYPE_INVALID))
1128		return -EUCLEAN;
1129
1130	if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1131		dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1132		refs = btrfs_extent_data_ref_count(leaf, dref);
1133	} else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1134		sref = (struct btrfs_shared_data_ref *)(iref + 1);
1135		refs = btrfs_shared_data_ref_count(leaf, sref);
1136	} else {
1137		refs = 1;
1138		/*
1139		 * For tree blocks we can only drop one ref for it, and tree
1140		 * blocks should not have refs > 1.
1141		 *
1142		 * Furthermore if we're inserting a new inline backref, we
1143		 * won't reach this path either. That would be
1144		 * setup_inline_extent_backref().
1145		 */
1146		if (unlikely(refs_to_mod != -1)) {
1147			struct btrfs_key key;
1148
1149			btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1150
1151			btrfs_print_leaf(leaf);
1152			btrfs_err(fs_info,
1153			"invalid refs_to_mod for tree block %llu, has %d expect -1",
1154				  key.objectid, refs_to_mod);
1155			return -EUCLEAN;
1156		}
1157	}
1158
1159	if (unlikely(refs_to_mod < 0 && refs < -refs_to_mod)) {
1160		struct btrfs_key key;
1161		u32 extent_size;
1162
1163		btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1164		if (key.type == BTRFS_METADATA_ITEM_KEY)
1165			extent_size = fs_info->nodesize;
1166		else
1167			extent_size = key.offset;
1168		btrfs_print_leaf(leaf);
1169		btrfs_err(fs_info,
1170"invalid refs_to_mod for backref entry, iref %lu extent %llu num_bytes %u, has %d expect >= -%llu",
1171			  (unsigned long)iref, key.objectid, extent_size,
1172			  refs_to_mod, refs);
1173		return -EUCLEAN;
1174	}
1175	refs += refs_to_mod;
1176
1177	if (refs > 0) {
1178		if (type == BTRFS_EXTENT_DATA_REF_KEY)
1179			btrfs_set_extent_data_ref_count(leaf, dref, refs);
1180		else
1181			btrfs_set_shared_data_ref_count(leaf, sref, refs);
1182	} else {
1183		size =  btrfs_extent_inline_ref_size(type);
1184		item_size = btrfs_item_size(leaf, path->slots[0]);
1185		ptr = (unsigned long)iref;
1186		end = (unsigned long)ei + item_size;
1187		if (ptr + size < end)
1188			memmove_extent_buffer(leaf, ptr, ptr + size,
1189					      end - ptr - size);
1190		item_size -= size;
1191		btrfs_truncate_item(trans, path, item_size, 1);
1192	}
1193	btrfs_mark_buffer_dirty(trans, leaf);
1194	return 0;
1195}
1196
1197static noinline_for_stack
1198int insert_inline_extent_backref(struct btrfs_trans_handle *trans,
1199				 struct btrfs_path *path,
1200				 u64 bytenr, u64 num_bytes, u64 parent,
1201				 u64 root_objectid, u64 owner,
1202				 u64 offset, int refs_to_add,
1203				 struct btrfs_delayed_extent_op *extent_op)
1204{
1205	struct btrfs_extent_inline_ref *iref;
1206	int ret;
1207
1208	ret = lookup_inline_extent_backref(trans, path, &iref, bytenr,
1209					   num_bytes, parent, root_objectid,
1210					   owner, offset, 1);
1211	if (ret == 0) {
1212		/*
1213		 * We're adding refs to a tree block we already own, this
1214		 * should not happen at all.
1215		 */
1216		if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1217			btrfs_print_leaf(path->nodes[0]);
1218			btrfs_crit(trans->fs_info,
1219"adding refs to an existing tree ref, bytenr %llu num_bytes %llu root_objectid %llu slot %u",
1220				   bytenr, num_bytes, root_objectid, path->slots[0]);
1221			return -EUCLEAN;
1222		}
1223		ret = update_inline_extent_backref(trans, path, iref,
1224						   refs_to_add, extent_op);
1225	} else if (ret == -ENOENT) {
1226		setup_inline_extent_backref(trans, path, iref, parent,
1227					    root_objectid, owner, offset,
1228					    refs_to_add, extent_op);
1229		ret = 0;
1230	}
1231	return ret;
1232}
1233
1234static int remove_extent_backref(struct btrfs_trans_handle *trans,
1235				 struct btrfs_root *root,
1236				 struct btrfs_path *path,
1237				 struct btrfs_extent_inline_ref *iref,
1238				 int refs_to_drop, int is_data)
1239{
1240	int ret = 0;
1241
1242	BUG_ON(!is_data && refs_to_drop != 1);
1243	if (iref)
1244		ret = update_inline_extent_backref(trans, path, iref,
1245						   -refs_to_drop, NULL);
1246	else if (is_data)
1247		ret = remove_extent_data_ref(trans, root, path, refs_to_drop);
1248	else
1249		ret = btrfs_del_item(trans, root, path);
1250	return ret;
1251}
1252
1253static int btrfs_issue_discard(struct block_device *bdev, u64 start, u64 len,
1254			       u64 *discarded_bytes)
1255{
1256	int j, ret = 0;
1257	u64 bytes_left, end;
1258	u64 aligned_start = ALIGN(start, 1 << SECTOR_SHIFT);
1259
1260	/* Adjust the range to be aligned to 512B sectors if necessary. */
1261	if (start != aligned_start) {
1262		len -= aligned_start - start;
1263		len = round_down(len, 1 << SECTOR_SHIFT);
1264		start = aligned_start;
1265	}
1266
1267	*discarded_bytes = 0;
1268
1269	if (!len)
1270		return 0;
1271
1272	end = start + len;
1273	bytes_left = len;
1274
1275	/* Skip any superblocks on this device. */
1276	for (j = 0; j < BTRFS_SUPER_MIRROR_MAX; j++) {
1277		u64 sb_start = btrfs_sb_offset(j);
1278		u64 sb_end = sb_start + BTRFS_SUPER_INFO_SIZE;
1279		u64 size = sb_start - start;
1280
1281		if (!in_range(sb_start, start, bytes_left) &&
1282		    !in_range(sb_end, start, bytes_left) &&
1283		    !in_range(start, sb_start, BTRFS_SUPER_INFO_SIZE))
1284			continue;
1285
1286		/*
1287		 * Superblock spans beginning of range.  Adjust start and
1288		 * try again.
1289		 */
1290		if (sb_start <= start) {
1291			start += sb_end - start;
1292			if (start > end) {
1293				bytes_left = 0;
1294				break;
1295			}
1296			bytes_left = end - start;
1297			continue;
1298		}
1299
1300		if (size) {
1301			ret = blkdev_issue_discard(bdev, start >> SECTOR_SHIFT,
1302						   size >> SECTOR_SHIFT,
1303						   GFP_NOFS);
1304			if (!ret)
1305				*discarded_bytes += size;
1306			else if (ret != -EOPNOTSUPP)
1307				return ret;
1308		}
1309
1310		start = sb_end;
1311		if (start > end) {
1312			bytes_left = 0;
1313			break;
1314		}
1315		bytes_left = end - start;
1316	}
1317
1318	if (bytes_left) {
 
 
1319		ret = blkdev_issue_discard(bdev, start >> SECTOR_SHIFT,
1320					   bytes_left >> SECTOR_SHIFT,
1321					   GFP_NOFS);
1322		if (!ret)
1323			*discarded_bytes += bytes_left;
 
 
 
 
 
 
 
 
 
 
 
 
 
1324	}
 
1325	return ret;
1326}
1327
1328static int do_discard_extent(struct btrfs_discard_stripe *stripe, u64 *bytes)
1329{
1330	struct btrfs_device *dev = stripe->dev;
1331	struct btrfs_fs_info *fs_info = dev->fs_info;
1332	struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
1333	u64 phys = stripe->physical;
1334	u64 len = stripe->length;
1335	u64 discarded = 0;
1336	int ret = 0;
1337
1338	/* Zone reset on a zoned filesystem */
1339	if (btrfs_can_zone_reset(dev, phys, len)) {
1340		u64 src_disc;
1341
1342		ret = btrfs_reset_device_zone(dev, phys, len, &discarded);
1343		if (ret)
1344			goto out;
1345
1346		if (!btrfs_dev_replace_is_ongoing(dev_replace) ||
1347		    dev != dev_replace->srcdev)
1348			goto out;
1349
1350		src_disc = discarded;
1351
1352		/* Send to replace target as well */
1353		ret = btrfs_reset_device_zone(dev_replace->tgtdev, phys, len,
1354					      &discarded);
1355		discarded += src_disc;
1356	} else if (bdev_max_discard_sectors(stripe->dev->bdev)) {
1357		ret = btrfs_issue_discard(dev->bdev, phys, len, &discarded);
1358	} else {
1359		ret = 0;
1360		*bytes = 0;
1361	}
1362
1363out:
1364	*bytes = discarded;
1365	return ret;
1366}
1367
1368int btrfs_discard_extent(struct btrfs_fs_info *fs_info, u64 bytenr,
1369			 u64 num_bytes, u64 *actual_bytes)
1370{
1371	int ret = 0;
1372	u64 discarded_bytes = 0;
1373	u64 end = bytenr + num_bytes;
1374	u64 cur = bytenr;
1375
1376	/*
1377	 * Avoid races with device replace and make sure the devices in the
1378	 * stripes don't go away while we are discarding.
1379	 */
1380	btrfs_bio_counter_inc_blocked(fs_info);
1381	while (cur < end) {
1382		struct btrfs_discard_stripe *stripes;
1383		unsigned int num_stripes;
1384		int i;
1385
1386		num_bytes = end - cur;
1387		stripes = btrfs_map_discard(fs_info, cur, &num_bytes, &num_stripes);
1388		if (IS_ERR(stripes)) {
1389			ret = PTR_ERR(stripes);
1390			if (ret == -EOPNOTSUPP)
1391				ret = 0;
1392			break;
1393		}
1394
1395		for (i = 0; i < num_stripes; i++) {
1396			struct btrfs_discard_stripe *stripe = stripes + i;
1397			u64 bytes;
1398
1399			if (!stripe->dev->bdev) {
1400				ASSERT(btrfs_test_opt(fs_info, DEGRADED));
1401				continue;
1402			}
1403
1404			if (!test_bit(BTRFS_DEV_STATE_WRITEABLE,
1405					&stripe->dev->dev_state))
1406				continue;
1407
1408			ret = do_discard_extent(stripe, &bytes);
1409			if (ret) {
1410				/*
1411				 * Keep going if discard is not supported by the
1412				 * device.
1413				 */
1414				if (ret != -EOPNOTSUPP)
1415					break;
1416				ret = 0;
1417			} else {
1418				discarded_bytes += bytes;
1419			}
1420		}
1421		kfree(stripes);
1422		if (ret)
1423			break;
1424		cur += num_bytes;
1425	}
1426	btrfs_bio_counter_dec(fs_info);
1427	if (actual_bytes)
1428		*actual_bytes = discarded_bytes;
1429	return ret;
1430}
1431
1432/* Can return -ENOMEM */
1433int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
1434			 struct btrfs_ref *generic_ref)
1435{
1436	struct btrfs_fs_info *fs_info = trans->fs_info;
1437	int ret;
1438
1439	ASSERT(generic_ref->type != BTRFS_REF_NOT_SET &&
1440	       generic_ref->action);
1441	BUG_ON(generic_ref->type == BTRFS_REF_METADATA &&
1442	       generic_ref->tree_ref.ref_root == BTRFS_TREE_LOG_OBJECTID);
1443
1444	if (generic_ref->type == BTRFS_REF_METADATA)
1445		ret = btrfs_add_delayed_tree_ref(trans, generic_ref, NULL);
1446	else
1447		ret = btrfs_add_delayed_data_ref(trans, generic_ref, 0);
1448
1449	btrfs_ref_tree_mod(fs_info, generic_ref);
1450
1451	return ret;
1452}
1453
1454/*
1455 * Insert backreference for a given extent.
1456 *
1457 * The counterpart is in __btrfs_free_extent(), with examples and more details
1458 * how it works.
1459 *
1460 * @trans:	    Handle of transaction
1461 *
1462 * @node:	    The delayed ref node used to get the bytenr/length for
1463 *		    extent whose references are incremented.
1464 *
1465 * @parent:	    If this is a shared extent (BTRFS_SHARED_DATA_REF_KEY/
1466 *		    BTRFS_SHARED_BLOCK_REF_KEY) then it holds the logical
1467 *		    bytenr of the parent block. Since new extents are always
1468 *		    created with indirect references, this will only be the case
1469 *		    when relocating a shared extent. In that case, root_objectid
1470 *		    will be BTRFS_TREE_RELOC_OBJECTID. Otherwise, parent must
1471 *		    be 0
1472 *
1473 * @root_objectid:  The id of the root where this modification has originated,
1474 *		    this can be either one of the well-known metadata trees or
1475 *		    the subvolume id which references this extent.
1476 *
1477 * @owner:	    For data extents it is the inode number of the owning file.
1478 *		    For metadata extents this parameter holds the level in the
1479 *		    tree of the extent.
1480 *
1481 * @offset:	    For metadata extents the offset is ignored and is currently
1482 *		    always passed as 0. For data extents it is the fileoffset
1483 *		    this extent belongs to.
1484 *
1485 * @extent_op       Pointer to a structure, holding information necessary when
1486 *                  updating a tree block's flags
1487 *
1488 */
1489static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
1490				  struct btrfs_delayed_ref_node *node,
1491				  u64 parent, u64 root_objectid,
1492				  u64 owner, u64 offset,
1493				  struct btrfs_delayed_extent_op *extent_op)
1494{
1495	struct btrfs_path *path;
1496	struct extent_buffer *leaf;
1497	struct btrfs_extent_item *item;
1498	struct btrfs_key key;
1499	u64 bytenr = node->bytenr;
1500	u64 num_bytes = node->num_bytes;
 
 
1501	u64 refs;
1502	int refs_to_add = node->ref_mod;
1503	int ret;
1504
1505	path = btrfs_alloc_path();
1506	if (!path)
1507		return -ENOMEM;
1508
1509	/* this will setup the path even if it fails to insert the back ref */
1510	ret = insert_inline_extent_backref(trans, path, bytenr, num_bytes,
1511					   parent, root_objectid, owner,
1512					   offset, refs_to_add, extent_op);
1513	if ((ret < 0 && ret != -EAGAIN) || !ret)
1514		goto out;
1515
1516	/*
1517	 * Ok we had -EAGAIN which means we didn't have space to insert and
1518	 * inline extent ref, so just update the reference count and add a
1519	 * normal backref.
1520	 */
1521	leaf = path->nodes[0];
1522	btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1523	item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1524	refs = btrfs_extent_refs(leaf, item);
1525	btrfs_set_extent_refs(leaf, item, refs + refs_to_add);
1526	if (extent_op)
1527		__run_delayed_extent_op(extent_op, leaf, item);
1528
1529	btrfs_mark_buffer_dirty(trans, leaf);
1530	btrfs_release_path(path);
1531
1532	/* now insert the actual backref */
1533	if (owner < BTRFS_FIRST_FREE_OBJECTID)
1534		ret = insert_tree_block_ref(trans, path, bytenr, parent,
1535					    root_objectid);
1536	else
1537		ret = insert_extent_data_ref(trans, path, bytenr, parent,
1538					     root_objectid, owner, offset,
1539					     refs_to_add);
1540
1541	if (ret)
1542		btrfs_abort_transaction(trans, ret);
1543out:
1544	btrfs_free_path(path);
1545	return ret;
1546}
1547
1548static void free_head_ref_squota_rsv(struct btrfs_fs_info *fs_info,
1549				     struct btrfs_delayed_ref_head *href)
1550{
1551	u64 root = href->owning_root;
1552
1553	/*
1554	 * Don't check must_insert_reserved, as this is called from contexts
1555	 * where it has already been unset.
1556	 */
1557	if (btrfs_qgroup_mode(fs_info) != BTRFS_QGROUP_MODE_SIMPLE ||
1558	    !href->is_data || !is_fstree(root))
1559		return;
1560
1561	btrfs_qgroup_free_refroot(fs_info, root, href->reserved_bytes,
1562				  BTRFS_QGROUP_RSV_DATA);
1563}
1564
1565static int run_delayed_data_ref(struct btrfs_trans_handle *trans,
1566				struct btrfs_delayed_ref_head *href,
1567				struct btrfs_delayed_ref_node *node,
1568				struct btrfs_delayed_extent_op *extent_op,
1569				bool insert_reserved)
1570{
1571	int ret = 0;
1572	struct btrfs_delayed_data_ref *ref;
1573	u64 parent = 0;
1574	u64 flags = 0;
1575
1576	ref = btrfs_delayed_node_to_data_ref(node);
1577	trace_run_delayed_data_ref(trans->fs_info, node, ref, node->action);
1578
1579	if (node->type == BTRFS_SHARED_DATA_REF_KEY)
1580		parent = ref->parent;
1581
1582	if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
1583		struct btrfs_key key;
1584		struct btrfs_squota_delta delta = {
1585			.root = href->owning_root,
1586			.num_bytes = node->num_bytes,
1587			.is_data = true,
1588			.is_inc	= true,
1589			.generation = trans->transid,
1590		};
 
 
1591
1592		if (extent_op)
1593			flags |= extent_op->flags_to_set;
1594
1595		key.objectid = node->bytenr;
1596		key.type = BTRFS_EXTENT_ITEM_KEY;
1597		key.offset = node->num_bytes;
1598
1599		ret = alloc_reserved_file_extent(trans, parent, ref->root,
1600						 flags, ref->objectid,
1601						 ref->offset, &key,
1602						 node->ref_mod, href->owning_root);
1603		free_head_ref_squota_rsv(trans->fs_info, href);
1604		if (!ret)
1605			ret = btrfs_record_squota_delta(trans->fs_info, &delta);
1606	} else if (node->action == BTRFS_ADD_DELAYED_REF) {
1607		ret = __btrfs_inc_extent_ref(trans, node, parent, ref->root,
1608					     ref->objectid, ref->offset,
1609					     extent_op);
1610	} else if (node->action == BTRFS_DROP_DELAYED_REF) {
1611		ret = __btrfs_free_extent(trans, href, node, parent,
1612					  ref->root, ref->objectid,
1613					  ref->offset, extent_op);
1614	} else {
1615		BUG();
1616	}
1617	return ret;
1618}
1619
1620static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
1621				    struct extent_buffer *leaf,
1622				    struct btrfs_extent_item *ei)
1623{
1624	u64 flags = btrfs_extent_flags(leaf, ei);
1625	if (extent_op->update_flags) {
1626		flags |= extent_op->flags_to_set;
1627		btrfs_set_extent_flags(leaf, ei, flags);
1628	}
1629
1630	if (extent_op->update_key) {
1631		struct btrfs_tree_block_info *bi;
1632		BUG_ON(!(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK));
1633		bi = (struct btrfs_tree_block_info *)(ei + 1);
1634		btrfs_set_tree_block_key(leaf, bi, &extent_op->key);
1635	}
1636}
1637
1638static int run_delayed_extent_op(struct btrfs_trans_handle *trans,
1639				 struct btrfs_delayed_ref_head *head,
1640				 struct btrfs_delayed_extent_op *extent_op)
1641{
1642	struct btrfs_fs_info *fs_info = trans->fs_info;
1643	struct btrfs_root *root;
1644	struct btrfs_key key;
1645	struct btrfs_path *path;
1646	struct btrfs_extent_item *ei;
1647	struct extent_buffer *leaf;
1648	u32 item_size;
1649	int ret;
1650	int metadata = 1;
1651
1652	if (TRANS_ABORTED(trans))
1653		return 0;
1654
1655	if (!btrfs_fs_incompat(fs_info, SKINNY_METADATA))
1656		metadata = 0;
1657
1658	path = btrfs_alloc_path();
1659	if (!path)
1660		return -ENOMEM;
1661
1662	key.objectid = head->bytenr;
1663
1664	if (metadata) {
1665		key.type = BTRFS_METADATA_ITEM_KEY;
1666		key.offset = extent_op->level;
1667	} else {
1668		key.type = BTRFS_EXTENT_ITEM_KEY;
1669		key.offset = head->num_bytes;
1670	}
1671
1672	root = btrfs_extent_root(fs_info, key.objectid);
1673again:
1674	ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
1675	if (ret < 0) {
1676		goto out;
1677	} else if (ret > 0) {
1678		if (metadata) {
1679			if (path->slots[0] > 0) {
1680				path->slots[0]--;
1681				btrfs_item_key_to_cpu(path->nodes[0], &key,
1682						      path->slots[0]);
1683				if (key.objectid == head->bytenr &&
1684				    key.type == BTRFS_EXTENT_ITEM_KEY &&
1685				    key.offset == head->num_bytes)
1686					ret = 0;
1687			}
1688			if (ret > 0) {
1689				btrfs_release_path(path);
1690				metadata = 0;
1691
1692				key.objectid = head->bytenr;
1693				key.offset = head->num_bytes;
1694				key.type = BTRFS_EXTENT_ITEM_KEY;
1695				goto again;
1696			}
1697		} else {
1698			ret = -EUCLEAN;
1699			btrfs_err(fs_info,
1700		  "missing extent item for extent %llu num_bytes %llu level %d",
1701				  head->bytenr, head->num_bytes, extent_op->level);
1702			goto out;
1703		}
1704	}
1705
1706	leaf = path->nodes[0];
1707	item_size = btrfs_item_size(leaf, path->slots[0]);
1708
1709	if (unlikely(item_size < sizeof(*ei))) {
1710		ret = -EUCLEAN;
1711		btrfs_err(fs_info,
1712			  "unexpected extent item size, has %u expect >= %zu",
1713			  item_size, sizeof(*ei));
1714		btrfs_abort_transaction(trans, ret);
1715		goto out;
1716	}
1717
1718	ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1719	__run_delayed_extent_op(extent_op, leaf, ei);
1720
1721	btrfs_mark_buffer_dirty(trans, leaf);
1722out:
1723	btrfs_free_path(path);
1724	return ret;
1725}
1726
1727static int run_delayed_tree_ref(struct btrfs_trans_handle *trans,
1728				struct btrfs_delayed_ref_head *href,
1729				struct btrfs_delayed_ref_node *node,
1730				struct btrfs_delayed_extent_op *extent_op,
1731				bool insert_reserved)
1732{
1733	int ret = 0;
1734	struct btrfs_fs_info *fs_info = trans->fs_info;
1735	struct btrfs_delayed_tree_ref *ref;
1736	u64 parent = 0;
1737	u64 ref_root = 0;
1738
1739	ref = btrfs_delayed_node_to_tree_ref(node);
1740	trace_run_delayed_tree_ref(trans->fs_info, node, ref, node->action);
1741
1742	if (node->type == BTRFS_SHARED_BLOCK_REF_KEY)
1743		parent = ref->parent;
1744	ref_root = ref->root;
1745
1746	if (unlikely(node->ref_mod != 1)) {
1747		btrfs_err(trans->fs_info,
1748	"btree block %llu has %d references rather than 1: action %d ref_root %llu parent %llu",
1749			  node->bytenr, node->ref_mod, node->action, ref_root,
1750			  parent);
1751		return -EUCLEAN;
1752	}
1753	if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
1754		struct btrfs_squota_delta delta = {
1755			.root = href->owning_root,
1756			.num_bytes = fs_info->nodesize,
1757			.is_data = false,
1758			.is_inc = true,
1759			.generation = trans->transid,
1760		};
1761
1762		BUG_ON(!extent_op || !extent_op->update_flags);
1763		ret = alloc_reserved_tree_block(trans, node, extent_op);
1764		if (!ret)
1765			btrfs_record_squota_delta(fs_info, &delta);
1766	} else if (node->action == BTRFS_ADD_DELAYED_REF) {
1767		ret = __btrfs_inc_extent_ref(trans, node, parent, ref_root,
1768					     ref->level, 0, extent_op);
1769	} else if (node->action == BTRFS_DROP_DELAYED_REF) {
1770		ret = __btrfs_free_extent(trans, href, node, parent, ref_root,
1771					  ref->level, 0, extent_op);
1772	} else {
1773		BUG();
1774	}
1775	return ret;
1776}
1777
1778/* helper function to actually process a single delayed ref entry */
1779static int run_one_delayed_ref(struct btrfs_trans_handle *trans,
1780			       struct btrfs_delayed_ref_head *href,
1781			       struct btrfs_delayed_ref_node *node,
1782			       struct btrfs_delayed_extent_op *extent_op,
1783			       bool insert_reserved)
1784{
1785	int ret = 0;
1786
1787	if (TRANS_ABORTED(trans)) {
1788		if (insert_reserved) {
1789			btrfs_pin_extent(trans, node->bytenr, node->num_bytes, 1);
1790			free_head_ref_squota_rsv(trans->fs_info, href);
1791		}
1792		return 0;
1793	}
1794
1795	if (node->type == BTRFS_TREE_BLOCK_REF_KEY ||
1796	    node->type == BTRFS_SHARED_BLOCK_REF_KEY)
1797		ret = run_delayed_tree_ref(trans, href, node, extent_op,
1798					   insert_reserved);
1799	else if (node->type == BTRFS_EXTENT_DATA_REF_KEY ||
1800		 node->type == BTRFS_SHARED_DATA_REF_KEY)
1801		ret = run_delayed_data_ref(trans, href, node, extent_op,
1802					   insert_reserved);
1803	else if (node->type == BTRFS_EXTENT_OWNER_REF_KEY)
1804		ret = 0;
1805	else
1806		BUG();
1807	if (ret && insert_reserved)
1808		btrfs_pin_extent(trans, node->bytenr, node->num_bytes, 1);
1809	if (ret < 0)
1810		btrfs_err(trans->fs_info,
1811"failed to run delayed ref for logical %llu num_bytes %llu type %u action %u ref_mod %d: %d",
1812			  node->bytenr, node->num_bytes, node->type,
1813			  node->action, node->ref_mod, ret);
1814	return ret;
1815}
1816
1817static inline struct btrfs_delayed_ref_node *
1818select_delayed_ref(struct btrfs_delayed_ref_head *head)
1819{
1820	struct btrfs_delayed_ref_node *ref;
1821
1822	if (RB_EMPTY_ROOT(&head->ref_tree.rb_root))
1823		return NULL;
1824
1825	/*
1826	 * Select a delayed ref of type BTRFS_ADD_DELAYED_REF first.
1827	 * This is to prevent a ref count from going down to zero, which deletes
1828	 * the extent item from the extent tree, when there still are references
1829	 * to add, which would fail because they would not find the extent item.
1830	 */
1831	if (!list_empty(&head->ref_add_list))
1832		return list_first_entry(&head->ref_add_list,
1833				struct btrfs_delayed_ref_node, add_list);
1834
1835	ref = rb_entry(rb_first_cached(&head->ref_tree),
1836		       struct btrfs_delayed_ref_node, ref_node);
1837	ASSERT(list_empty(&ref->add_list));
1838	return ref;
1839}
1840
1841static void unselect_delayed_ref_head(struct btrfs_delayed_ref_root *delayed_refs,
1842				      struct btrfs_delayed_ref_head *head)
1843{
1844	spin_lock(&delayed_refs->lock);
1845	head->processing = false;
1846	delayed_refs->num_heads_ready++;
1847	spin_unlock(&delayed_refs->lock);
1848	btrfs_delayed_ref_unlock(head);
1849}
1850
1851static struct btrfs_delayed_extent_op *cleanup_extent_op(
1852				struct btrfs_delayed_ref_head *head)
1853{
1854	struct btrfs_delayed_extent_op *extent_op = head->extent_op;
1855
1856	if (!extent_op)
1857		return NULL;
1858
1859	if (head->must_insert_reserved) {
1860		head->extent_op = NULL;
1861		btrfs_free_delayed_extent_op(extent_op);
1862		return NULL;
1863	}
1864	return extent_op;
1865}
1866
1867static int run_and_cleanup_extent_op(struct btrfs_trans_handle *trans,
1868				     struct btrfs_delayed_ref_head *head)
1869{
1870	struct btrfs_delayed_extent_op *extent_op;
1871	int ret;
1872
1873	extent_op = cleanup_extent_op(head);
1874	if (!extent_op)
1875		return 0;
1876	head->extent_op = NULL;
1877	spin_unlock(&head->lock);
1878	ret = run_delayed_extent_op(trans, head, extent_op);
1879	btrfs_free_delayed_extent_op(extent_op);
1880	return ret ? ret : 1;
1881}
1882
1883u64 btrfs_cleanup_ref_head_accounting(struct btrfs_fs_info *fs_info,
1884				  struct btrfs_delayed_ref_root *delayed_refs,
1885				  struct btrfs_delayed_ref_head *head)
1886{
1887	u64 ret = 0;
1888
1889	/*
1890	 * We had csum deletions accounted for in our delayed refs rsv, we need
1891	 * to drop the csum leaves for this update from our delayed_refs_rsv.
1892	 */
1893	if (head->total_ref_mod < 0 && head->is_data) {
1894		int nr_csums;
1895
1896		spin_lock(&delayed_refs->lock);
1897		delayed_refs->pending_csums -= head->num_bytes;
1898		spin_unlock(&delayed_refs->lock);
1899		nr_csums = btrfs_csum_bytes_to_leaves(fs_info, head->num_bytes);
1900
1901		btrfs_delayed_refs_rsv_release(fs_info, 0, nr_csums);
1902
1903		ret = btrfs_calc_delayed_ref_csum_bytes(fs_info, nr_csums);
1904	}
1905	/* must_insert_reserved can be set only if we didn't run the head ref. */
1906	if (head->must_insert_reserved)
1907		free_head_ref_squota_rsv(fs_info, head);
1908
1909	return ret;
1910}
1911
1912static int cleanup_ref_head(struct btrfs_trans_handle *trans,
1913			    struct btrfs_delayed_ref_head *head,
1914			    u64 *bytes_released)
1915{
1916
1917	struct btrfs_fs_info *fs_info = trans->fs_info;
1918	struct btrfs_delayed_ref_root *delayed_refs;
1919	int ret;
1920
1921	delayed_refs = &trans->transaction->delayed_refs;
1922
1923	ret = run_and_cleanup_extent_op(trans, head);
1924	if (ret < 0) {
1925		unselect_delayed_ref_head(delayed_refs, head);
1926		btrfs_debug(fs_info, "run_delayed_extent_op returned %d", ret);
1927		return ret;
1928	} else if (ret) {
1929		return ret;
1930	}
1931
1932	/*
1933	 * Need to drop our head ref lock and re-acquire the delayed ref lock
1934	 * and then re-check to make sure nobody got added.
1935	 */
1936	spin_unlock(&head->lock);
1937	spin_lock(&delayed_refs->lock);
1938	spin_lock(&head->lock);
1939	if (!RB_EMPTY_ROOT(&head->ref_tree.rb_root) || head->extent_op) {
1940		spin_unlock(&head->lock);
1941		spin_unlock(&delayed_refs->lock);
1942		return 1;
1943	}
1944	btrfs_delete_ref_head(delayed_refs, head);
1945	spin_unlock(&head->lock);
1946	spin_unlock(&delayed_refs->lock);
1947
1948	if (head->must_insert_reserved) {
1949		btrfs_pin_extent(trans, head->bytenr, head->num_bytes, 1);
1950		if (head->is_data) {
1951			struct btrfs_root *csum_root;
1952
1953			csum_root = btrfs_csum_root(fs_info, head->bytenr);
1954			ret = btrfs_del_csums(trans, csum_root, head->bytenr,
1955					      head->num_bytes);
1956		}
1957	}
1958
1959	*bytes_released += btrfs_cleanup_ref_head_accounting(fs_info, delayed_refs, head);
1960
1961	trace_run_delayed_ref_head(fs_info, head, 0);
1962	btrfs_delayed_ref_unlock(head);
1963	btrfs_put_delayed_ref_head(head);
1964	return ret;
1965}
1966
1967static struct btrfs_delayed_ref_head *btrfs_obtain_ref_head(
1968					struct btrfs_trans_handle *trans)
1969{
1970	struct btrfs_delayed_ref_root *delayed_refs =
1971		&trans->transaction->delayed_refs;
1972	struct btrfs_delayed_ref_head *head = NULL;
1973	int ret;
1974
1975	spin_lock(&delayed_refs->lock);
1976	head = btrfs_select_ref_head(delayed_refs);
1977	if (!head) {
1978		spin_unlock(&delayed_refs->lock);
1979		return head;
1980	}
1981
1982	/*
1983	 * Grab the lock that says we are going to process all the refs for
1984	 * this head
1985	 */
1986	ret = btrfs_delayed_ref_lock(delayed_refs, head);
1987	spin_unlock(&delayed_refs->lock);
1988
1989	/*
1990	 * We may have dropped the spin lock to get the head mutex lock, and
1991	 * that might have given someone else time to free the head.  If that's
1992	 * true, it has been removed from our list and we can move on.
1993	 */
1994	if (ret == -EAGAIN)
1995		head = ERR_PTR(-EAGAIN);
1996
1997	return head;
1998}
1999
2000static int btrfs_run_delayed_refs_for_head(struct btrfs_trans_handle *trans,
2001					   struct btrfs_delayed_ref_head *locked_ref,
2002					   u64 *bytes_released)
2003{
2004	struct btrfs_fs_info *fs_info = trans->fs_info;
2005	struct btrfs_delayed_ref_root *delayed_refs;
2006	struct btrfs_delayed_extent_op *extent_op;
2007	struct btrfs_delayed_ref_node *ref;
2008	bool must_insert_reserved;
2009	int ret;
2010
2011	delayed_refs = &trans->transaction->delayed_refs;
2012
2013	lockdep_assert_held(&locked_ref->mutex);
2014	lockdep_assert_held(&locked_ref->lock);
2015
2016	while ((ref = select_delayed_ref(locked_ref))) {
2017		if (ref->seq &&
2018		    btrfs_check_delayed_seq(fs_info, ref->seq)) {
2019			spin_unlock(&locked_ref->lock);
2020			unselect_delayed_ref_head(delayed_refs, locked_ref);
2021			return -EAGAIN;
2022		}
2023
2024		rb_erase_cached(&ref->ref_node, &locked_ref->ref_tree);
2025		RB_CLEAR_NODE(&ref->ref_node);
2026		if (!list_empty(&ref->add_list))
2027			list_del(&ref->add_list);
2028		/*
2029		 * When we play the delayed ref, also correct the ref_mod on
2030		 * head
2031		 */
2032		switch (ref->action) {
2033		case BTRFS_ADD_DELAYED_REF:
2034		case BTRFS_ADD_DELAYED_EXTENT:
2035			locked_ref->ref_mod -= ref->ref_mod;
2036			break;
2037		case BTRFS_DROP_DELAYED_REF:
2038			locked_ref->ref_mod += ref->ref_mod;
2039			break;
2040		default:
2041			WARN_ON(1);
2042		}
2043		atomic_dec(&delayed_refs->num_entries);
2044
2045		/*
2046		 * Record the must_insert_reserved flag before we drop the
2047		 * spin lock.
2048		 */
2049		must_insert_reserved = locked_ref->must_insert_reserved;
2050		/*
2051		 * Unsetting this on the head ref relinquishes ownership of
2052		 * the rsv_bytes, so it is critical that every possible code
2053		 * path from here forward frees all reserves including qgroup
2054		 * reserve.
2055		 */
2056		locked_ref->must_insert_reserved = false;
2057
2058		extent_op = locked_ref->extent_op;
2059		locked_ref->extent_op = NULL;
2060		spin_unlock(&locked_ref->lock);
2061
2062		ret = run_one_delayed_ref(trans, locked_ref, ref, extent_op,
2063					  must_insert_reserved);
2064		btrfs_delayed_refs_rsv_release(fs_info, 1, 0);
2065		*bytes_released += btrfs_calc_delayed_ref_bytes(fs_info, 1);
2066
2067		btrfs_free_delayed_extent_op(extent_op);
2068		if (ret) {
2069			unselect_delayed_ref_head(delayed_refs, locked_ref);
2070			btrfs_put_delayed_ref(ref);
2071			return ret;
2072		}
2073
2074		btrfs_put_delayed_ref(ref);
2075		cond_resched();
2076
2077		spin_lock(&locked_ref->lock);
2078		btrfs_merge_delayed_refs(fs_info, delayed_refs, locked_ref);
2079	}
2080
2081	return 0;
2082}
2083
2084/*
2085 * Returns 0 on success or if called with an already aborted transaction.
2086 * Returns -ENOMEM or -EIO on failure and will abort the transaction.
2087 */
2088static noinline int __btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
2089					     u64 min_bytes)
2090{
2091	struct btrfs_fs_info *fs_info = trans->fs_info;
2092	struct btrfs_delayed_ref_root *delayed_refs;
2093	struct btrfs_delayed_ref_head *locked_ref = NULL;
2094	int ret;
2095	unsigned long count = 0;
2096	unsigned long max_count = 0;
2097	u64 bytes_processed = 0;
2098
2099	delayed_refs = &trans->transaction->delayed_refs;
2100	if (min_bytes == 0) {
2101		max_count = delayed_refs->num_heads_ready;
2102		min_bytes = U64_MAX;
2103	}
2104
2105	do {
2106		if (!locked_ref) {
2107			locked_ref = btrfs_obtain_ref_head(trans);
2108			if (IS_ERR_OR_NULL(locked_ref)) {
2109				if (PTR_ERR(locked_ref) == -EAGAIN) {
2110					continue;
2111				} else {
2112					break;
2113				}
2114			}
2115			count++;
2116		}
2117		/*
2118		 * We need to try and merge add/drops of the same ref since we
2119		 * can run into issues with relocate dropping the implicit ref
2120		 * and then it being added back again before the drop can
2121		 * finish.  If we merged anything we need to re-loop so we can
2122		 * get a good ref.
2123		 * Or we can get node references of the same type that weren't
2124		 * merged when created due to bumps in the tree mod seq, and
2125		 * we need to merge them to prevent adding an inline extent
2126		 * backref before dropping it (triggering a BUG_ON at
2127		 * insert_inline_extent_backref()).
2128		 */
2129		spin_lock(&locked_ref->lock);
2130		btrfs_merge_delayed_refs(fs_info, delayed_refs, locked_ref);
2131
2132		ret = btrfs_run_delayed_refs_for_head(trans, locked_ref, &bytes_processed);
2133		if (ret < 0 && ret != -EAGAIN) {
2134			/*
2135			 * Error, btrfs_run_delayed_refs_for_head already
2136			 * unlocked everything so just bail out
2137			 */
2138			return ret;
2139		} else if (!ret) {
2140			/*
2141			 * Success, perform the usual cleanup of a processed
2142			 * head
2143			 */
2144			ret = cleanup_ref_head(trans, locked_ref, &bytes_processed);
2145			if (ret > 0 ) {
2146				/* We dropped our lock, we need to loop. */
2147				ret = 0;
2148				continue;
2149			} else if (ret) {
2150				return ret;
2151			}
2152		}
2153
2154		/*
2155		 * Either success case or btrfs_run_delayed_refs_for_head
2156		 * returned -EAGAIN, meaning we need to select another head
2157		 */
2158
2159		locked_ref = NULL;
2160		cond_resched();
2161	} while ((min_bytes != U64_MAX && bytes_processed < min_bytes) ||
2162		 (max_count > 0 && count < max_count) ||
2163		 locked_ref);
2164
2165	return 0;
2166}
2167
2168#ifdef SCRAMBLE_DELAYED_REFS
2169/*
2170 * Normally delayed refs get processed in ascending bytenr order. This
2171 * correlates in most cases to the order added. To expose dependencies on this
2172 * order, we start to process the tree in the middle instead of the beginning
2173 */
2174static u64 find_middle(struct rb_root *root)
2175{
2176	struct rb_node *n = root->rb_node;
2177	struct btrfs_delayed_ref_node *entry;
2178	int alt = 1;
2179	u64 middle;
2180	u64 first = 0, last = 0;
2181
2182	n = rb_first(root);
2183	if (n) {
2184		entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2185		first = entry->bytenr;
2186	}
2187	n = rb_last(root);
2188	if (n) {
2189		entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2190		last = entry->bytenr;
2191	}
2192	n = root->rb_node;
2193
2194	while (n) {
2195		entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2196		WARN_ON(!entry->in_tree);
2197
2198		middle = entry->bytenr;
2199
2200		if (alt)
2201			n = n->rb_left;
2202		else
2203			n = n->rb_right;
2204
2205		alt = 1 - alt;
2206	}
2207	return middle;
2208}
2209#endif
2210
2211/*
2212 * Start processing the delayed reference count updates and extent insertions
2213 * we have queued up so far.
2214 *
2215 * @trans:	Transaction handle.
2216 * @min_bytes:	How many bytes of delayed references to process. After this
2217 *		many bytes we stop processing delayed references if there are
2218 *		any more. If 0 it means to run all existing delayed references,
2219 *		but not new ones added after running all existing ones.
2220 *		Use (u64)-1 (U64_MAX) to run all existing delayed references
2221 *		plus any new ones that are added.
2222 *
2223 * Returns 0 on success or if called with an aborted transaction
2224 * Returns <0 on error and aborts the transaction
2225 */
2226int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans, u64 min_bytes)
2227{
2228	struct btrfs_fs_info *fs_info = trans->fs_info;
2229	struct btrfs_delayed_ref_root *delayed_refs;
2230	int ret;
2231
2232	/* We'll clean this up in btrfs_cleanup_transaction */
2233	if (TRANS_ABORTED(trans))
2234		return 0;
2235
2236	if (test_bit(BTRFS_FS_CREATING_FREE_SPACE_TREE, &fs_info->flags))
2237		return 0;
2238
2239	delayed_refs = &trans->transaction->delayed_refs;
2240again:
2241#ifdef SCRAMBLE_DELAYED_REFS
2242	delayed_refs->run_delayed_start = find_middle(&delayed_refs->root);
2243#endif
2244	ret = __btrfs_run_delayed_refs(trans, min_bytes);
2245	if (ret < 0) {
2246		btrfs_abort_transaction(trans, ret);
2247		return ret;
2248	}
2249
2250	if (min_bytes == U64_MAX) {
2251		btrfs_create_pending_block_groups(trans);
2252
2253		spin_lock(&delayed_refs->lock);
2254		if (RB_EMPTY_ROOT(&delayed_refs->href_root.rb_root)) {
2255			spin_unlock(&delayed_refs->lock);
2256			return 0;
2257		}
2258		spin_unlock(&delayed_refs->lock);
2259
2260		cond_resched();
2261		goto again;
2262	}
2263
2264	return 0;
2265}
2266
2267int btrfs_set_disk_extent_flags(struct btrfs_trans_handle *trans,
2268				struct extent_buffer *eb, u64 flags)
2269{
2270	struct btrfs_delayed_extent_op *extent_op;
2271	int level = btrfs_header_level(eb);
2272	int ret;
2273
2274	extent_op = btrfs_alloc_delayed_extent_op();
2275	if (!extent_op)
2276		return -ENOMEM;
2277
2278	extent_op->flags_to_set = flags;
2279	extent_op->update_flags = true;
2280	extent_op->update_key = false;
2281	extent_op->level = level;
2282
2283	ret = btrfs_add_delayed_extent_op(trans, eb->start, eb->len, extent_op);
 
2284	if (ret)
2285		btrfs_free_delayed_extent_op(extent_op);
2286	return ret;
2287}
2288
2289static noinline int check_delayed_ref(struct btrfs_root *root,
2290				      struct btrfs_path *path,
2291				      u64 objectid, u64 offset, u64 bytenr)
2292{
2293	struct btrfs_delayed_ref_head *head;
2294	struct btrfs_delayed_ref_node *ref;
2295	struct btrfs_delayed_data_ref *data_ref;
2296	struct btrfs_delayed_ref_root *delayed_refs;
2297	struct btrfs_transaction *cur_trans;
2298	struct rb_node *node;
2299	int ret = 0;
2300
2301	spin_lock(&root->fs_info->trans_lock);
2302	cur_trans = root->fs_info->running_transaction;
2303	if (cur_trans)
2304		refcount_inc(&cur_trans->use_count);
2305	spin_unlock(&root->fs_info->trans_lock);
2306	if (!cur_trans)
2307		return 0;
2308
2309	delayed_refs = &cur_trans->delayed_refs;
2310	spin_lock(&delayed_refs->lock);
2311	head = btrfs_find_delayed_ref_head(delayed_refs, bytenr);
2312	if (!head) {
2313		spin_unlock(&delayed_refs->lock);
2314		btrfs_put_transaction(cur_trans);
2315		return 0;
2316	}
2317
2318	if (!mutex_trylock(&head->mutex)) {
2319		if (path->nowait) {
2320			spin_unlock(&delayed_refs->lock);
2321			btrfs_put_transaction(cur_trans);
2322			return -EAGAIN;
2323		}
2324
2325		refcount_inc(&head->refs);
2326		spin_unlock(&delayed_refs->lock);
2327
2328		btrfs_release_path(path);
2329
2330		/*
2331		 * Mutex was contended, block until it's released and let
2332		 * caller try again
2333		 */
2334		mutex_lock(&head->mutex);
2335		mutex_unlock(&head->mutex);
2336		btrfs_put_delayed_ref_head(head);
2337		btrfs_put_transaction(cur_trans);
2338		return -EAGAIN;
2339	}
2340	spin_unlock(&delayed_refs->lock);
2341
2342	spin_lock(&head->lock);
2343	/*
2344	 * XXX: We should replace this with a proper search function in the
2345	 * future.
2346	 */
2347	for (node = rb_first_cached(&head->ref_tree); node;
2348	     node = rb_next(node)) {
 
 
 
2349		ref = rb_entry(node, struct btrfs_delayed_ref_node, ref_node);
2350		/* If it's a shared ref we know a cross reference exists */
2351		if (ref->type != BTRFS_EXTENT_DATA_REF_KEY) {
2352			ret = 1;
2353			break;
2354		}
2355
2356		data_ref = btrfs_delayed_node_to_data_ref(ref);
 
2357
2358		/*
2359		 * If our ref doesn't match the one we're currently looking at
2360		 * then we have a cross reference.
2361		 */
2362		if (data_ref->root != root->root_key.objectid ||
2363		    data_ref->objectid != objectid ||
2364		    data_ref->offset != offset) {
2365			ret = 1;
2366			break;
2367		}
2368	}
2369	spin_unlock(&head->lock);
2370	mutex_unlock(&head->mutex);
2371	btrfs_put_transaction(cur_trans);
2372	return ret;
2373}
2374
2375static noinline int check_committed_ref(struct btrfs_root *root,
2376					struct btrfs_path *path,
2377					u64 objectid, u64 offset, u64 bytenr,
2378					bool strict)
2379{
2380	struct btrfs_fs_info *fs_info = root->fs_info;
2381	struct btrfs_root *extent_root = btrfs_extent_root(fs_info, bytenr);
2382	struct extent_buffer *leaf;
2383	struct btrfs_extent_data_ref *ref;
2384	struct btrfs_extent_inline_ref *iref;
2385	struct btrfs_extent_item *ei;
2386	struct btrfs_key key;
2387	u32 item_size;
2388	u32 expected_size;
2389	int type;
2390	int ret;
2391
2392	key.objectid = bytenr;
2393	key.offset = (u64)-1;
2394	key.type = BTRFS_EXTENT_ITEM_KEY;
2395
2396	ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
2397	if (ret < 0)
2398		goto out;
2399	if (ret == 0) {
2400		/*
2401		 * Key with offset -1 found, there would have to exist an extent
2402		 * item with such offset, but this is out of the valid range.
2403		 */
2404		ret = -EUCLEAN;
2405		goto out;
2406	}
2407
2408	ret = -ENOENT;
2409	if (path->slots[0] == 0)
2410		goto out;
2411
2412	path->slots[0]--;
2413	leaf = path->nodes[0];
2414	btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2415
2416	if (key.objectid != bytenr || key.type != BTRFS_EXTENT_ITEM_KEY)
2417		goto out;
2418
2419	ret = 1;
2420	item_size = btrfs_item_size(leaf, path->slots[0]);
2421	ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2422	expected_size = sizeof(*ei) + btrfs_extent_inline_ref_size(BTRFS_EXTENT_DATA_REF_KEY);
2423
2424	/* No inline refs; we need to bail before checking for owner ref. */
2425	if (item_size == sizeof(*ei))
2426		goto out;
2427
2428	/* Check for an owner ref; skip over it to the real inline refs. */
2429	iref = (struct btrfs_extent_inline_ref *)(ei + 1);
2430	type = btrfs_get_extent_inline_ref_type(leaf, iref, BTRFS_REF_TYPE_DATA);
2431	if (btrfs_fs_incompat(fs_info, SIMPLE_QUOTA) && type == BTRFS_EXTENT_OWNER_REF_KEY) {
2432		expected_size += btrfs_extent_inline_ref_size(BTRFS_EXTENT_OWNER_REF_KEY);
2433		iref = (struct btrfs_extent_inline_ref *)(iref + 1);
2434	}
2435
2436	/* If extent item has more than 1 inline ref then it's shared */
2437	if (item_size != expected_size)
2438		goto out;
2439
2440	/*
2441	 * If extent created before last snapshot => it's shared unless the
2442	 * snapshot has been deleted. Use the heuristic if strict is false.
2443	 */
2444	if (!strict &&
2445	    (btrfs_extent_generation(leaf, ei) <=
2446	     btrfs_root_last_snapshot(&root->root_item)))
2447		goto out;
2448
2449	/* If this extent has SHARED_DATA_REF then it's shared */
2450	type = btrfs_get_extent_inline_ref_type(leaf, iref, BTRFS_REF_TYPE_DATA);
2451	if (type != BTRFS_EXTENT_DATA_REF_KEY)
2452		goto out;
2453
2454	ref = (struct btrfs_extent_data_ref *)(&iref->offset);
2455	if (btrfs_extent_refs(leaf, ei) !=
2456	    btrfs_extent_data_ref_count(leaf, ref) ||
2457	    btrfs_extent_data_ref_root(leaf, ref) !=
2458	    root->root_key.objectid ||
2459	    btrfs_extent_data_ref_objectid(leaf, ref) != objectid ||
2460	    btrfs_extent_data_ref_offset(leaf, ref) != offset)
2461		goto out;
2462
2463	ret = 0;
2464out:
2465	return ret;
2466}
2467
2468int btrfs_cross_ref_exist(struct btrfs_root *root, u64 objectid, u64 offset,
2469			  u64 bytenr, bool strict, struct btrfs_path *path)
2470{
2471	int ret;
2472
2473	do {
2474		ret = check_committed_ref(root, path, objectid,
2475					  offset, bytenr, strict);
2476		if (ret && ret != -ENOENT)
2477			goto out;
2478
2479		ret = check_delayed_ref(root, path, objectid, offset, bytenr);
2480	} while (ret == -EAGAIN);
2481
2482out:
2483	btrfs_release_path(path);
2484	if (btrfs_is_data_reloc_root(root))
2485		WARN_ON(ret > 0);
2486	return ret;
2487}
2488
2489static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
2490			   struct btrfs_root *root,
2491			   struct extent_buffer *buf,
2492			   int full_backref, int inc)
2493{
2494	struct btrfs_fs_info *fs_info = root->fs_info;
2495	u64 bytenr;
2496	u64 num_bytes;
2497	u64 parent;
2498	u64 ref_root;
2499	u32 nritems;
2500	struct btrfs_key key;
2501	struct btrfs_file_extent_item *fi;
2502	struct btrfs_ref generic_ref = { 0 };
2503	bool for_reloc = btrfs_header_flag(buf, BTRFS_HEADER_FLAG_RELOC);
2504	int i;
2505	int action;
2506	int level;
2507	int ret = 0;
2508
2509	if (btrfs_is_testing(fs_info))
2510		return 0;
2511
2512	ref_root = btrfs_header_owner(buf);
2513	nritems = btrfs_header_nritems(buf);
2514	level = btrfs_header_level(buf);
2515
2516	if (!test_bit(BTRFS_ROOT_SHAREABLE, &root->state) && level == 0)
2517		return 0;
2518
2519	if (full_backref)
2520		parent = buf->start;
2521	else
2522		parent = 0;
2523	if (inc)
2524		action = BTRFS_ADD_DELAYED_REF;
2525	else
2526		action = BTRFS_DROP_DELAYED_REF;
2527
2528	for (i = 0; i < nritems; i++) {
 
 
 
 
 
 
2529		if (level == 0) {
2530			btrfs_item_key_to_cpu(buf, &key, i);
2531			if (key.type != BTRFS_EXTENT_DATA_KEY)
2532				continue;
2533			fi = btrfs_item_ptr(buf, i,
2534					    struct btrfs_file_extent_item);
2535			if (btrfs_file_extent_type(buf, fi) ==
2536			    BTRFS_FILE_EXTENT_INLINE)
2537				continue;
2538			bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
2539			if (bytenr == 0)
2540				continue;
2541
2542			num_bytes = btrfs_file_extent_disk_num_bytes(buf, fi);
 
 
2543			key.offset -= btrfs_file_extent_offset(buf, fi);
2544			btrfs_init_generic_ref(&generic_ref, action, bytenr,
2545					       num_bytes, parent, ref_root);
2546			btrfs_init_data_ref(&generic_ref, ref_root, key.objectid,
2547					    key.offset, root->root_key.objectid,
2548					    for_reloc);
2549			if (inc)
2550				ret = btrfs_inc_extent_ref(trans, &generic_ref);
2551			else
2552				ret = btrfs_free_extent(trans, &generic_ref);
2553			if (ret)
2554				goto fail;
2555		} else {
2556			bytenr = btrfs_node_blockptr(buf, i);
2557			num_bytes = fs_info->nodesize;
2558			/* We don't know the owning_root, use 0. */
2559			btrfs_init_generic_ref(&generic_ref, action, bytenr,
2560					       num_bytes, parent, 0);
2561			btrfs_init_tree_ref(&generic_ref, level - 1, ref_root,
2562					    root->root_key.objectid, for_reloc);
2563			if (inc)
2564				ret = btrfs_inc_extent_ref(trans, &generic_ref);
2565			else
2566				ret = btrfs_free_extent(trans, &generic_ref);
2567			if (ret)
2568				goto fail;
2569		}
2570	}
2571	return 0;
2572fail:
2573	return ret;
2574}
2575
2576int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2577		  struct extent_buffer *buf, int full_backref)
2578{
2579	return __btrfs_mod_ref(trans, root, buf, full_backref, 1);
2580}
2581
2582int btrfs_dec_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2583		  struct extent_buffer *buf, int full_backref)
2584{
2585	return __btrfs_mod_ref(trans, root, buf, full_backref, 0);
2586}
2587
2588static u64 get_alloc_profile_by_root(struct btrfs_root *root, int data)
2589{
2590	struct btrfs_fs_info *fs_info = root->fs_info;
2591	u64 flags;
2592	u64 ret;
2593
2594	if (data)
2595		flags = BTRFS_BLOCK_GROUP_DATA;
2596	else if (root == fs_info->chunk_root)
2597		flags = BTRFS_BLOCK_GROUP_SYSTEM;
2598	else
2599		flags = BTRFS_BLOCK_GROUP_METADATA;
2600
2601	ret = btrfs_get_alloc_profile(fs_info, flags);
2602	return ret;
2603}
2604
2605static u64 first_logical_byte(struct btrfs_fs_info *fs_info)
2606{
2607	struct rb_node *leftmost;
2608	u64 bytenr = 0;
2609
2610	read_lock(&fs_info->block_group_cache_lock);
2611	/* Get the block group with the lowest logical start address. */
2612	leftmost = rb_first_cached(&fs_info->block_group_cache_tree);
2613	if (leftmost) {
2614		struct btrfs_block_group *bg;
2615
2616		bg = rb_entry(leftmost, struct btrfs_block_group, cache_node);
2617		bytenr = bg->start;
2618	}
2619	read_unlock(&fs_info->block_group_cache_lock);
2620
2621	return bytenr;
2622}
2623
2624static int pin_down_extent(struct btrfs_trans_handle *trans,
2625			   struct btrfs_block_group *cache,
2626			   u64 bytenr, u64 num_bytes, int reserved)
2627{
2628	struct btrfs_fs_info *fs_info = cache->fs_info;
2629
2630	spin_lock(&cache->space_info->lock);
2631	spin_lock(&cache->lock);
2632	cache->pinned += num_bytes;
2633	btrfs_space_info_update_bytes_pinned(fs_info, cache->space_info,
2634					     num_bytes);
2635	if (reserved) {
2636		cache->reserved -= num_bytes;
2637		cache->space_info->bytes_reserved -= num_bytes;
2638	}
2639	spin_unlock(&cache->lock);
2640	spin_unlock(&cache->space_info->lock);
2641
2642	set_extent_bit(&trans->transaction->pinned_extents, bytenr,
2643		       bytenr + num_bytes - 1, EXTENT_DIRTY, NULL);
2644	return 0;
2645}
2646
2647int btrfs_pin_extent(struct btrfs_trans_handle *trans,
2648		     u64 bytenr, u64 num_bytes, int reserved)
2649{
2650	struct btrfs_block_group *cache;
2651
2652	cache = btrfs_lookup_block_group(trans->fs_info, bytenr);
2653	BUG_ON(!cache); /* Logic error */
2654
2655	pin_down_extent(trans, cache, bytenr, num_bytes, reserved);
2656
2657	btrfs_put_block_group(cache);
2658	return 0;
2659}
2660
2661int btrfs_pin_extent_for_log_replay(struct btrfs_trans_handle *trans,
2662				    const struct extent_buffer *eb)
2663{
2664	struct btrfs_block_group *cache;
2665	int ret;
2666
2667	cache = btrfs_lookup_block_group(trans->fs_info, eb->start);
2668	if (!cache)
2669		return -EINVAL;
2670
2671	/*
2672	 * Fully cache the free space first so that our pin removes the free space
2673	 * from the cache.
2674	 */
2675	ret = btrfs_cache_block_group(cache, true);
2676	if (ret)
2677		goto out;
2678
2679	pin_down_extent(trans, cache, eb->start, eb->len, 0);
2680
2681	/* remove us from the free space cache (if we're there at all) */
2682	ret = btrfs_remove_free_space(cache, eb->start, eb->len);
2683out:
2684	btrfs_put_block_group(cache);
2685	return ret;
2686}
2687
2688static int __exclude_logged_extent(struct btrfs_fs_info *fs_info,
2689				   u64 start, u64 num_bytes)
2690{
2691	int ret;
2692	struct btrfs_block_group *block_group;
2693
2694	block_group = btrfs_lookup_block_group(fs_info, start);
2695	if (!block_group)
2696		return -EINVAL;
2697
2698	ret = btrfs_cache_block_group(block_group, true);
2699	if (ret)
2700		goto out;
2701
2702	ret = btrfs_remove_free_space(block_group, start, num_bytes);
2703out:
2704	btrfs_put_block_group(block_group);
2705	return ret;
2706}
2707
2708int btrfs_exclude_logged_extents(struct extent_buffer *eb)
2709{
2710	struct btrfs_fs_info *fs_info = eb->fs_info;
2711	struct btrfs_file_extent_item *item;
2712	struct btrfs_key key;
2713	int found_type;
2714	int i;
2715	int ret = 0;
2716
2717	if (!btrfs_fs_incompat(fs_info, MIXED_GROUPS))
2718		return 0;
2719
2720	for (i = 0; i < btrfs_header_nritems(eb); i++) {
2721		btrfs_item_key_to_cpu(eb, &key, i);
2722		if (key.type != BTRFS_EXTENT_DATA_KEY)
2723			continue;
2724		item = btrfs_item_ptr(eb, i, struct btrfs_file_extent_item);
2725		found_type = btrfs_file_extent_type(eb, item);
2726		if (found_type == BTRFS_FILE_EXTENT_INLINE)
2727			continue;
2728		if (btrfs_file_extent_disk_bytenr(eb, item) == 0)
2729			continue;
2730		key.objectid = btrfs_file_extent_disk_bytenr(eb, item);
2731		key.offset = btrfs_file_extent_disk_num_bytes(eb, item);
2732		ret = __exclude_logged_extent(fs_info, key.objectid, key.offset);
2733		if (ret)
2734			break;
2735	}
2736
2737	return ret;
2738}
2739
2740static void
2741btrfs_inc_block_group_reservations(struct btrfs_block_group *bg)
2742{
2743	atomic_inc(&bg->reservations);
2744}
2745
2746/*
2747 * Returns the free cluster for the given space info and sets empty_cluster to
2748 * what it should be based on the mount options.
2749 */
2750static struct btrfs_free_cluster *
2751fetch_cluster_info(struct btrfs_fs_info *fs_info,
2752		   struct btrfs_space_info *space_info, u64 *empty_cluster)
2753{
2754	struct btrfs_free_cluster *ret = NULL;
2755
2756	*empty_cluster = 0;
2757	if (btrfs_mixed_space_info(space_info))
2758		return ret;
2759
2760	if (space_info->flags & BTRFS_BLOCK_GROUP_METADATA) {
2761		ret = &fs_info->meta_alloc_cluster;
2762		if (btrfs_test_opt(fs_info, SSD))
2763			*empty_cluster = SZ_2M;
2764		else
2765			*empty_cluster = SZ_64K;
2766	} else if ((space_info->flags & BTRFS_BLOCK_GROUP_DATA) &&
2767		   btrfs_test_opt(fs_info, SSD_SPREAD)) {
2768		*empty_cluster = SZ_2M;
2769		ret = &fs_info->data_alloc_cluster;
2770	}
2771
2772	return ret;
2773}
2774
2775static int unpin_extent_range(struct btrfs_fs_info *fs_info,
2776			      u64 start, u64 end,
2777			      const bool return_free_space)
2778{
2779	struct btrfs_block_group *cache = NULL;
2780	struct btrfs_space_info *space_info;
2781	struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
2782	struct btrfs_free_cluster *cluster = NULL;
2783	u64 len;
2784	u64 total_unpinned = 0;
2785	u64 empty_cluster = 0;
2786	bool readonly;
2787	int ret = 0;
2788
2789	while (start <= end) {
2790		readonly = false;
2791		if (!cache ||
2792		    start >= cache->start + cache->length) {
2793			if (cache)
2794				btrfs_put_block_group(cache);
2795			total_unpinned = 0;
2796			cache = btrfs_lookup_block_group(fs_info, start);
2797			if (cache == NULL) {
2798				/* Logic error, something removed the block group. */
2799				ret = -EUCLEAN;
2800				goto out;
2801			}
2802
2803			cluster = fetch_cluster_info(fs_info,
2804						     cache->space_info,
2805						     &empty_cluster);
2806			empty_cluster <<= 1;
2807		}
2808
2809		len = cache->start + cache->length - start;
2810		len = min(len, end + 1 - start);
2811
2812		if (return_free_space)
2813			btrfs_add_free_space(cache, start, len);
2814
2815		start += len;
2816		total_unpinned += len;
2817		space_info = cache->space_info;
2818
2819		/*
2820		 * If this space cluster has been marked as fragmented and we've
2821		 * unpinned enough in this block group to potentially allow a
2822		 * cluster to be created inside of it go ahead and clear the
2823		 * fragmented check.
2824		 */
2825		if (cluster && cluster->fragmented &&
2826		    total_unpinned > empty_cluster) {
2827			spin_lock(&cluster->lock);
2828			cluster->fragmented = 0;
2829			spin_unlock(&cluster->lock);
2830		}
2831
2832		spin_lock(&space_info->lock);
2833		spin_lock(&cache->lock);
2834		cache->pinned -= len;
2835		btrfs_space_info_update_bytes_pinned(fs_info, space_info, -len);
2836		space_info->max_extent_size = 0;
2837		if (cache->ro) {
2838			space_info->bytes_readonly += len;
2839			readonly = true;
2840		} else if (btrfs_is_zoned(fs_info)) {
2841			/* Need reset before reusing in a zoned block group */
2842			space_info->bytes_zone_unusable += len;
 
2843			readonly = true;
2844		}
2845		spin_unlock(&cache->lock);
2846		if (!readonly && return_free_space &&
2847		    global_rsv->space_info == space_info) {
2848			spin_lock(&global_rsv->lock);
2849			if (!global_rsv->full) {
2850				u64 to_add = min(len, global_rsv->size -
2851						      global_rsv->reserved);
2852
2853				global_rsv->reserved += to_add;
2854				btrfs_space_info_update_bytes_may_use(fs_info,
2855						space_info, to_add);
2856				if (global_rsv->reserved >= global_rsv->size)
2857					global_rsv->full = 1;
2858				len -= to_add;
2859			}
2860			spin_unlock(&global_rsv->lock);
2861		}
2862		/* Add to any tickets we may have */
2863		if (!readonly && return_free_space && len)
2864			btrfs_try_granting_tickets(fs_info, space_info);
2865		spin_unlock(&space_info->lock);
2866	}
2867
2868	if (cache)
2869		btrfs_put_block_group(cache);
2870out:
2871	return ret;
2872}
2873
2874int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans)
2875{
2876	struct btrfs_fs_info *fs_info = trans->fs_info;
2877	struct btrfs_block_group *block_group, *tmp;
2878	struct list_head *deleted_bgs;
2879	struct extent_io_tree *unpin;
2880	u64 start;
2881	u64 end;
2882	int ret;
2883
2884	unpin = &trans->transaction->pinned_extents;
2885
2886	while (!TRANS_ABORTED(trans)) {
2887		struct extent_state *cached_state = NULL;
2888
2889		mutex_lock(&fs_info->unused_bg_unpin_mutex);
2890		if (!find_first_extent_bit(unpin, 0, &start, &end,
2891					   EXTENT_DIRTY, &cached_state)) {
2892			mutex_unlock(&fs_info->unused_bg_unpin_mutex);
2893			break;
2894		}
2895
2896		if (btrfs_test_opt(fs_info, DISCARD_SYNC))
2897			ret = btrfs_discard_extent(fs_info, start,
2898						   end + 1 - start, NULL);
2899
2900		clear_extent_dirty(unpin, start, end, &cached_state);
2901		ret = unpin_extent_range(fs_info, start, end, true);
2902		BUG_ON(ret);
2903		mutex_unlock(&fs_info->unused_bg_unpin_mutex);
2904		free_extent_state(cached_state);
2905		cond_resched();
2906	}
2907
2908	if (btrfs_test_opt(fs_info, DISCARD_ASYNC)) {
2909		btrfs_discard_calc_delay(&fs_info->discard_ctl);
2910		btrfs_discard_schedule_work(&fs_info->discard_ctl, true);
2911	}
2912
2913	/*
2914	 * Transaction is finished.  We don't need the lock anymore.  We
2915	 * do need to clean up the block groups in case of a transaction
2916	 * abort.
2917	 */
2918	deleted_bgs = &trans->transaction->deleted_bgs;
2919	list_for_each_entry_safe(block_group, tmp, deleted_bgs, bg_list) {
2920		u64 trimmed = 0;
2921
2922		ret = -EROFS;
2923		if (!TRANS_ABORTED(trans))
2924			ret = btrfs_discard_extent(fs_info,
2925						   block_group->start,
2926						   block_group->length,
2927						   &trimmed);
2928
2929		list_del_init(&block_group->bg_list);
2930		btrfs_unfreeze_block_group(block_group);
2931		btrfs_put_block_group(block_group);
2932
2933		if (ret) {
2934			const char *errstr = btrfs_decode_error(ret);
2935			btrfs_warn(fs_info,
2936			   "discard failed while removing blockgroup: errno=%d %s",
2937				   ret, errstr);
2938		}
2939	}
2940
2941	return 0;
2942}
2943
2944/*
2945 * Parse an extent item's inline extents looking for a simple quotas owner ref.
2946 *
2947 * @fs_info:	the btrfs_fs_info for this mount
2948 * @leaf:	a leaf in the extent tree containing the extent item
2949 * @slot:	the slot in the leaf where the extent item is found
2950 *
2951 * Returns the objectid of the root that originally allocated the extent item
2952 * if the inline owner ref is expected and present, otherwise 0.
2953 *
2954 * If an extent item has an owner ref item, it will be the first inline ref
2955 * item. Therefore the logic is to check whether there are any inline ref
2956 * items, then check the type of the first one.
2957 */
2958u64 btrfs_get_extent_owner_root(struct btrfs_fs_info *fs_info,
2959				struct extent_buffer *leaf, int slot)
2960{
2961	struct btrfs_extent_item *ei;
2962	struct btrfs_extent_inline_ref *iref;
2963	struct btrfs_extent_owner_ref *oref;
2964	unsigned long ptr;
2965	unsigned long end;
2966	int type;
2967
2968	if (!btrfs_fs_incompat(fs_info, SIMPLE_QUOTA))
2969		return 0;
2970
2971	ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item);
2972	ptr = (unsigned long)(ei + 1);
2973	end = (unsigned long)ei + btrfs_item_size(leaf, slot);
2974
2975	/* No inline ref items of any kind, can't check type. */
2976	if (ptr == end)
2977		return 0;
2978
2979	iref = (struct btrfs_extent_inline_ref *)ptr;
2980	type = btrfs_get_extent_inline_ref_type(leaf, iref, BTRFS_REF_TYPE_ANY);
2981
2982	/* We found an owner ref, get the root out of it. */
2983	if (type == BTRFS_EXTENT_OWNER_REF_KEY) {
2984		oref = (struct btrfs_extent_owner_ref *)(&iref->offset);
2985		return btrfs_extent_owner_ref_root_id(leaf, oref);
2986	}
2987
2988	/* We have inline refs, but not an owner ref. */
2989	return 0;
2990}
2991
2992static int do_free_extent_accounting(struct btrfs_trans_handle *trans,
2993				     u64 bytenr, struct btrfs_squota_delta *delta)
2994{
2995	int ret;
2996	u64 num_bytes = delta->num_bytes;
2997
2998	if (delta->is_data) {
2999		struct btrfs_root *csum_root;
3000
3001		csum_root = btrfs_csum_root(trans->fs_info, bytenr);
3002		ret = btrfs_del_csums(trans, csum_root, bytenr, num_bytes);
3003		if (ret) {
3004			btrfs_abort_transaction(trans, ret);
3005			return ret;
3006		}
3007
3008		ret = btrfs_delete_raid_extent(trans, bytenr, num_bytes);
3009		if (ret) {
3010			btrfs_abort_transaction(trans, ret);
3011			return ret;
3012		}
3013	}
3014
3015	ret = btrfs_record_squota_delta(trans->fs_info, delta);
3016	if (ret) {
3017		btrfs_abort_transaction(trans, ret);
3018		return ret;
3019	}
3020
3021	ret = add_to_free_space_tree(trans, bytenr, num_bytes);
3022	if (ret) {
3023		btrfs_abort_transaction(trans, ret);
3024		return ret;
3025	}
3026
3027	ret = btrfs_update_block_group(trans, bytenr, num_bytes, false);
3028	if (ret)
3029		btrfs_abort_transaction(trans, ret);
3030
3031	return ret;
3032}
3033
3034#define abort_and_dump(trans, path, fmt, args...)	\
3035({							\
3036	btrfs_abort_transaction(trans, -EUCLEAN);	\
3037	btrfs_print_leaf(path->nodes[0]);		\
3038	btrfs_crit(trans->fs_info, fmt, ##args);	\
3039})
3040
3041/*
3042 * Drop one or more refs of @node.
3043 *
3044 * 1. Locate the extent refs.
3045 *    It's either inline in EXTENT/METADATA_ITEM or in keyed SHARED_* item.
3046 *    Locate it, then reduce the refs number or remove the ref line completely.
3047 *
3048 * 2. Update the refs count in EXTENT/METADATA_ITEM
3049 *
3050 * Inline backref case:
3051 *
3052 * in extent tree we have:
3053 *
3054 * 	item 0 key (13631488 EXTENT_ITEM 1048576) itemoff 16201 itemsize 82
3055 *		refs 2 gen 6 flags DATA
3056 *		extent data backref root FS_TREE objectid 258 offset 0 count 1
3057 *		extent data backref root FS_TREE objectid 257 offset 0 count 1
3058 *
3059 * This function gets called with:
3060 *
3061 *    node->bytenr = 13631488
3062 *    node->num_bytes = 1048576
3063 *    root_objectid = FS_TREE
3064 *    owner_objectid = 257
3065 *    owner_offset = 0
3066 *    refs_to_drop = 1
3067 *
3068 * Then we should get some like:
3069 *
3070 * 	item 0 key (13631488 EXTENT_ITEM 1048576) itemoff 16201 itemsize 82
3071 *		refs 1 gen 6 flags DATA
3072 *		extent data backref root FS_TREE objectid 258 offset 0 count 1
3073 *
3074 * Keyed backref case:
3075 *
3076 * in extent tree we have:
3077 *
3078 *	item 0 key (13631488 EXTENT_ITEM 1048576) itemoff 3971 itemsize 24
3079 *		refs 754 gen 6 flags DATA
3080 *	[...]
3081 *	item 2 key (13631488 EXTENT_DATA_REF <HASH>) itemoff 3915 itemsize 28
3082 *		extent data backref root FS_TREE objectid 866 offset 0 count 1
3083 *
3084 * This function get called with:
3085 *
3086 *    node->bytenr = 13631488
3087 *    node->num_bytes = 1048576
3088 *    root_objectid = FS_TREE
3089 *    owner_objectid = 866
3090 *    owner_offset = 0
3091 *    refs_to_drop = 1
3092 *
3093 * Then we should get some like:
3094 *
3095 *	item 0 key (13631488 EXTENT_ITEM 1048576) itemoff 3971 itemsize 24
3096 *		refs 753 gen 6 flags DATA
3097 *
3098 * And that (13631488 EXTENT_DATA_REF <HASH>) gets removed.
3099 */
3100static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
3101			       struct btrfs_delayed_ref_head *href,
3102			       struct btrfs_delayed_ref_node *node, u64 parent,
3103			       u64 root_objectid, u64 owner_objectid,
3104			       u64 owner_offset,
3105			       struct btrfs_delayed_extent_op *extent_op)
3106{
3107	struct btrfs_fs_info *info = trans->fs_info;
3108	struct btrfs_key key;
3109	struct btrfs_path *path;
3110	struct btrfs_root *extent_root;
3111	struct extent_buffer *leaf;
3112	struct btrfs_extent_item *ei;
3113	struct btrfs_extent_inline_ref *iref;
3114	int ret;
3115	int is_data;
3116	int extent_slot = 0;
3117	int found_extent = 0;
3118	int num_to_del = 1;
3119	int refs_to_drop = node->ref_mod;
3120	u32 item_size;
3121	u64 refs;
3122	u64 bytenr = node->bytenr;
3123	u64 num_bytes = node->num_bytes;
 
 
3124	bool skinny_metadata = btrfs_fs_incompat(info, SKINNY_METADATA);
3125	u64 delayed_ref_root = href->owning_root;
3126
3127	extent_root = btrfs_extent_root(info, bytenr);
3128	ASSERT(extent_root);
3129
3130	path = btrfs_alloc_path();
3131	if (!path)
3132		return -ENOMEM;
3133
3134	is_data = owner_objectid >= BTRFS_FIRST_FREE_OBJECTID;
3135
3136	if (!is_data && refs_to_drop != 1) {
3137		btrfs_crit(info,
3138"invalid refs_to_drop, dropping more than 1 refs for tree block %llu refs_to_drop %u",
3139			   node->bytenr, refs_to_drop);
3140		ret = -EINVAL;
3141		btrfs_abort_transaction(trans, ret);
3142		goto out;
3143	}
3144
3145	if (is_data)
3146		skinny_metadata = false;
3147
3148	ret = lookup_extent_backref(trans, path, &iref, bytenr, num_bytes,
3149				    parent, root_objectid, owner_objectid,
3150				    owner_offset);
3151	if (ret == 0) {
3152		/*
3153		 * Either the inline backref or the SHARED_DATA_REF/
3154		 * SHARED_BLOCK_REF is found
3155		 *
3156		 * Here is a quick path to locate EXTENT/METADATA_ITEM.
3157		 * It's possible the EXTENT/METADATA_ITEM is near current slot.
3158		 */
3159		extent_slot = path->slots[0];
3160		while (extent_slot >= 0) {
3161			btrfs_item_key_to_cpu(path->nodes[0], &key,
3162					      extent_slot);
3163			if (key.objectid != bytenr)
3164				break;
3165			if (key.type == BTRFS_EXTENT_ITEM_KEY &&
3166			    key.offset == num_bytes) {
3167				found_extent = 1;
3168				break;
3169			}
3170			if (key.type == BTRFS_METADATA_ITEM_KEY &&
3171			    key.offset == owner_objectid) {
3172				found_extent = 1;
3173				break;
3174			}
3175
3176			/* Quick path didn't find the EXTEMT/METADATA_ITEM */
3177			if (path->slots[0] - extent_slot > 5)
3178				break;
3179			extent_slot--;
3180		}
3181
3182		if (!found_extent) {
3183			if (iref) {
3184				abort_and_dump(trans, path,
3185"invalid iref slot %u, no EXTENT/METADATA_ITEM found but has inline extent ref",
3186					   path->slots[0]);
3187				ret = -EUCLEAN;
3188				goto out;
3189			}
3190			/* Must be SHARED_* item, remove the backref first */
3191			ret = remove_extent_backref(trans, extent_root, path,
3192						    NULL, refs_to_drop, is_data);
3193			if (ret) {
3194				btrfs_abort_transaction(trans, ret);
3195				goto out;
3196			}
3197			btrfs_release_path(path);
3198
3199			/* Slow path to locate EXTENT/METADATA_ITEM */
3200			key.objectid = bytenr;
3201			key.type = BTRFS_EXTENT_ITEM_KEY;
3202			key.offset = num_bytes;
3203
3204			if (!is_data && skinny_metadata) {
3205				key.type = BTRFS_METADATA_ITEM_KEY;
3206				key.offset = owner_objectid;
3207			}
3208
3209			ret = btrfs_search_slot(trans, extent_root,
3210						&key, path, -1, 1);
3211			if (ret > 0 && skinny_metadata && path->slots[0]) {
3212				/*
3213				 * Couldn't find our skinny metadata item,
3214				 * see if we have ye olde extent item.
3215				 */
3216				path->slots[0]--;
3217				btrfs_item_key_to_cpu(path->nodes[0], &key,
3218						      path->slots[0]);
3219				if (key.objectid == bytenr &&
3220				    key.type == BTRFS_EXTENT_ITEM_KEY &&
3221				    key.offset == num_bytes)
3222					ret = 0;
3223			}
3224
3225			if (ret > 0 && skinny_metadata) {
3226				skinny_metadata = false;
3227				key.objectid = bytenr;
3228				key.type = BTRFS_EXTENT_ITEM_KEY;
3229				key.offset = num_bytes;
3230				btrfs_release_path(path);
3231				ret = btrfs_search_slot(trans, extent_root,
3232							&key, path, -1, 1);
3233			}
3234
3235			if (ret) {
3236				if (ret > 0)
3237					btrfs_print_leaf(path->nodes[0]);
3238				btrfs_err(info,
3239			"umm, got %d back from search, was looking for %llu, slot %d",
3240					  ret, bytenr, path->slots[0]);
3241			}
3242			if (ret < 0) {
3243				btrfs_abort_transaction(trans, ret);
3244				goto out;
3245			}
3246			extent_slot = path->slots[0];
3247		}
3248	} else if (WARN_ON(ret == -ENOENT)) {
3249		abort_and_dump(trans, path,
3250"unable to find ref byte nr %llu parent %llu root %llu owner %llu offset %llu slot %d",
3251			       bytenr, parent, root_objectid, owner_objectid,
3252			       owner_offset, path->slots[0]);
3253		goto out;
3254	} else {
3255		btrfs_abort_transaction(trans, ret);
3256		goto out;
3257	}
3258
3259	leaf = path->nodes[0];
3260	item_size = btrfs_item_size(leaf, extent_slot);
3261	if (unlikely(item_size < sizeof(*ei))) {
3262		ret = -EUCLEAN;
3263		btrfs_err(trans->fs_info,
3264			  "unexpected extent item size, has %u expect >= %zu",
3265			  item_size, sizeof(*ei));
3266		btrfs_abort_transaction(trans, ret);
3267		goto out;
3268	}
3269	ei = btrfs_item_ptr(leaf, extent_slot,
3270			    struct btrfs_extent_item);
3271	if (owner_objectid < BTRFS_FIRST_FREE_OBJECTID &&
3272	    key.type == BTRFS_EXTENT_ITEM_KEY) {
3273		struct btrfs_tree_block_info *bi;
3274
3275		if (item_size < sizeof(*ei) + sizeof(*bi)) {
3276			abort_and_dump(trans, path,
3277"invalid extent item size for key (%llu, %u, %llu) slot %u owner %llu, has %u expect >= %zu",
3278				       key.objectid, key.type, key.offset,
3279				       path->slots[0], owner_objectid, item_size,
3280				       sizeof(*ei) + sizeof(*bi));
3281			ret = -EUCLEAN;
3282			goto out;
3283		}
3284		bi = (struct btrfs_tree_block_info *)(ei + 1);
3285		WARN_ON(owner_objectid != btrfs_tree_block_level(leaf, bi));
3286	}
3287
3288	refs = btrfs_extent_refs(leaf, ei);
3289	if (refs < refs_to_drop) {
3290		abort_and_dump(trans, path,
3291		"trying to drop %d refs but we only have %llu for bytenr %llu slot %u",
3292			       refs_to_drop, refs, bytenr, path->slots[0]);
3293		ret = -EUCLEAN;
3294		goto out;
3295	}
3296	refs -= refs_to_drop;
3297
3298	if (refs > 0) {
3299		if (extent_op)
3300			__run_delayed_extent_op(extent_op, leaf, ei);
3301		/*
3302		 * In the case of inline back ref, reference count will
3303		 * be updated by remove_extent_backref
3304		 */
3305		if (iref) {
3306			if (!found_extent) {
3307				abort_and_dump(trans, path,
3308"invalid iref, got inlined extent ref but no EXTENT/METADATA_ITEM found, slot %u",
3309					       path->slots[0]);
3310				ret = -EUCLEAN;
3311				goto out;
3312			}
3313		} else {
3314			btrfs_set_extent_refs(leaf, ei, refs);
3315			btrfs_mark_buffer_dirty(trans, leaf);
3316		}
3317		if (found_extent) {
3318			ret = remove_extent_backref(trans, extent_root, path,
3319						    iref, refs_to_drop, is_data);
3320			if (ret) {
3321				btrfs_abort_transaction(trans, ret);
3322				goto out;
3323			}
3324		}
3325	} else {
3326		struct btrfs_squota_delta delta = {
3327			.root = delayed_ref_root,
3328			.num_bytes = num_bytes,
3329			.is_data = is_data,
3330			.is_inc = false,
3331			.generation = btrfs_extent_generation(leaf, ei),
3332		};
3333
3334		/* In this branch refs == 1 */
3335		if (found_extent) {
3336			if (is_data && refs_to_drop !=
3337			    extent_data_ref_count(path, iref)) {
3338				abort_and_dump(trans, path,
3339		"invalid refs_to_drop, current refs %u refs_to_drop %u slot %u",
3340					       extent_data_ref_count(path, iref),
3341					       refs_to_drop, path->slots[0]);
3342				ret = -EUCLEAN;
3343				goto out;
3344			}
3345			if (iref) {
3346				if (path->slots[0] != extent_slot) {
3347					abort_and_dump(trans, path,
3348"invalid iref, extent item key (%llu %u %llu) slot %u doesn't have wanted iref",
3349						       key.objectid, key.type,
3350						       key.offset, path->slots[0]);
3351					ret = -EUCLEAN;
3352					goto out;
3353				}
3354			} else {
3355				/*
3356				 * No inline ref, we must be at SHARED_* item,
3357				 * And it's single ref, it must be:
3358				 * |	extent_slot	  ||extent_slot + 1|
3359				 * [ EXTENT/METADATA_ITEM ][ SHARED_* ITEM ]
3360				 */
3361				if (path->slots[0] != extent_slot + 1) {
3362					abort_and_dump(trans, path,
3363	"invalid SHARED_* item slot %u, previous item is not EXTENT/METADATA_ITEM",
3364						       path->slots[0]);
3365					ret = -EUCLEAN;
3366					goto out;
3367				}
3368				path->slots[0] = extent_slot;
3369				num_to_del = 2;
3370			}
3371		}
3372		/*
3373		 * We can't infer the data owner from the delayed ref, so we need
3374		 * to try to get it from the owning ref item.
3375		 *
3376		 * If it is not present, then that extent was not written under
3377		 * simple quotas mode, so we don't need to account for its deletion.
3378		 */
3379		if (is_data)
3380			delta.root = btrfs_get_extent_owner_root(trans->fs_info,
3381								 leaf, extent_slot);
3382
3383		ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
3384				      num_to_del);
3385		if (ret) {
3386			btrfs_abort_transaction(trans, ret);
3387			goto out;
3388		}
3389		btrfs_release_path(path);
3390
3391		ret = do_free_extent_accounting(trans, bytenr, &delta);
3392	}
3393	btrfs_release_path(path);
3394
3395out:
3396	btrfs_free_path(path);
3397	return ret;
3398}
3399
3400/*
3401 * when we free an block, it is possible (and likely) that we free the last
3402 * delayed ref for that extent as well.  This searches the delayed ref tree for
3403 * a given extent, and if there are no other delayed refs to be processed, it
3404 * removes it from the tree.
3405 */
3406static noinline int check_ref_cleanup(struct btrfs_trans_handle *trans,
3407				      u64 bytenr)
3408{
 
3409	struct btrfs_delayed_ref_head *head;
3410	struct btrfs_delayed_ref_root *delayed_refs;
3411	int ret = 0;
3412
3413	delayed_refs = &trans->transaction->delayed_refs;
3414	spin_lock(&delayed_refs->lock);
3415	head = btrfs_find_delayed_ref_head(delayed_refs, bytenr);
3416	if (!head)
3417		goto out_delayed_unlock;
3418
3419	spin_lock(&head->lock);
3420	if (!RB_EMPTY_ROOT(&head->ref_tree.rb_root))
3421		goto out;
3422
3423	if (cleanup_extent_op(head) != NULL)
3424		goto out;
3425
3426	/*
3427	 * waiting for the lock here would deadlock.  If someone else has it
3428	 * locked they are already in the process of dropping it anyway
3429	 */
3430	if (!mutex_trylock(&head->mutex))
3431		goto out;
3432
3433	btrfs_delete_ref_head(delayed_refs, head);
3434	head->processing = false;
3435
3436	spin_unlock(&head->lock);
3437	spin_unlock(&delayed_refs->lock);
3438
3439	BUG_ON(head->extent_op);
3440	if (head->must_insert_reserved)
3441		ret = 1;
3442
3443	btrfs_cleanup_ref_head_accounting(trans->fs_info, delayed_refs, head);
3444	mutex_unlock(&head->mutex);
3445	btrfs_put_delayed_ref_head(head);
3446	return ret;
3447out:
3448	spin_unlock(&head->lock);
3449
3450out_delayed_unlock:
3451	spin_unlock(&delayed_refs->lock);
3452	return 0;
3453}
3454
3455void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
3456			   u64 root_id,
3457			   struct extent_buffer *buf,
3458			   u64 parent, int last_ref)
3459{
3460	struct btrfs_fs_info *fs_info = trans->fs_info;
3461	struct btrfs_block_group *bg;
3462	int ret;
3463
3464	if (root_id != BTRFS_TREE_LOG_OBJECTID) {
3465		struct btrfs_ref generic_ref = { 0 };
 
 
 
 
 
 
 
3466
3467		/*
3468		 * Assert that the extent buffer is not cleared due to
3469		 * EXTENT_BUFFER_ZONED_ZEROOUT. Please refer
3470		 * btrfs_clear_buffer_dirty() and btree_csum_one_bio() for
3471		 * detail.
3472		 */
3473		ASSERT(btrfs_header_bytenr(buf) != 0);
3474
3475		btrfs_init_generic_ref(&generic_ref, BTRFS_DROP_DELAYED_REF,
3476				       buf->start, buf->len, parent,
3477				       btrfs_header_owner(buf));
3478		btrfs_init_tree_ref(&generic_ref, btrfs_header_level(buf),
3479				    root_id, 0, false);
3480		btrfs_ref_tree_mod(fs_info, &generic_ref);
3481		ret = btrfs_add_delayed_tree_ref(trans, &generic_ref, NULL);
3482		BUG_ON(ret); /* -ENOMEM */
 
3483	}
3484
3485	if (!last_ref)
3486		return;
3487
3488	if (btrfs_header_generation(buf) != trans->transid)
3489		goto out;
3490
3491	if (root_id != BTRFS_TREE_LOG_OBJECTID) {
3492		ret = check_ref_cleanup(trans, buf->start);
3493		if (!ret)
3494			goto out;
3495	}
3496
3497	bg = btrfs_lookup_block_group(fs_info, buf->start);
3498
3499	if (btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
3500		pin_down_extent(trans, bg, buf->start, buf->len, 1);
3501		btrfs_put_block_group(bg);
3502		goto out;
3503	}
3504
3505	/*
3506	 * If there are tree mod log users we may have recorded mod log
3507	 * operations for this node.  If we re-allocate this node we
3508	 * could replay operations on this node that happened when it
3509	 * existed in a completely different root.  For example if it
3510	 * was part of root A, then was reallocated to root B, and we
3511	 * are doing a btrfs_old_search_slot(root b), we could replay
3512	 * operations that happened when the block was part of root A,
3513	 * giving us an inconsistent view of the btree.
3514	 *
3515	 * We are safe from races here because at this point no other
3516	 * node or root points to this extent buffer, so if after this
3517	 * check a new tree mod log user joins we will not have an
3518	 * existing log of operations on this node that we have to
3519	 * contend with.
3520	 */
3521
3522	if (test_bit(BTRFS_FS_TREE_MOD_LOG_USERS, &fs_info->flags)
3523		     || btrfs_is_zoned(fs_info)) {
3524		pin_down_extent(trans, bg, buf->start, buf->len, 1);
3525		btrfs_put_block_group(bg);
3526		goto out;
3527	}
3528
3529	WARN_ON(test_bit(EXTENT_BUFFER_DIRTY, &buf->bflags));
3530
3531	btrfs_add_free_space(bg, buf->start, buf->len);
3532	btrfs_free_reserved_bytes(bg, buf->len, 0);
3533	btrfs_put_block_group(bg);
3534	trace_btrfs_reserved_extent_free(fs_info, buf->start, buf->len);
3535
3536out:
3537
3538	/*
3539	 * Deleting the buffer, clear the corrupt flag since it doesn't
3540	 * matter anymore.
3541	 */
3542	clear_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags);
 
3543}
3544
3545/* Can return -ENOMEM */
3546int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_ref *ref)
3547{
3548	struct btrfs_fs_info *fs_info = trans->fs_info;
3549	int ret;
3550
3551	if (btrfs_is_testing(fs_info))
3552		return 0;
3553
3554	/*
3555	 * tree log blocks never actually go into the extent allocation
3556	 * tree, just update pinning info and exit early.
3557	 */
3558	if ((ref->type == BTRFS_REF_METADATA &&
3559	     ref->tree_ref.ref_root == BTRFS_TREE_LOG_OBJECTID) ||
3560	    (ref->type == BTRFS_REF_DATA &&
3561	     ref->data_ref.ref_root == BTRFS_TREE_LOG_OBJECTID)) {
3562		btrfs_pin_extent(trans, ref->bytenr, ref->len, 1);
3563		ret = 0;
3564	} else if (ref->type == BTRFS_REF_METADATA) {
3565		ret = btrfs_add_delayed_tree_ref(trans, ref, NULL);
3566	} else {
3567		ret = btrfs_add_delayed_data_ref(trans, ref, 0);
3568	}
3569
3570	if (!((ref->type == BTRFS_REF_METADATA &&
3571	       ref->tree_ref.ref_root == BTRFS_TREE_LOG_OBJECTID) ||
3572	      (ref->type == BTRFS_REF_DATA &&
3573	       ref->data_ref.ref_root == BTRFS_TREE_LOG_OBJECTID)))
3574		btrfs_ref_tree_mod(fs_info, ref);
3575
3576	return ret;
3577}
3578
3579enum btrfs_loop_type {
3580	/*
3581	 * Start caching block groups but do not wait for progress or for them
3582	 * to be done.
3583	 */
3584	LOOP_CACHING_NOWAIT,
3585
3586	/*
3587	 * Wait for the block group free_space >= the space we're waiting for if
3588	 * the block group isn't cached.
3589	 */
3590	LOOP_CACHING_WAIT,
3591
3592	/*
3593	 * Allow allocations to happen from block groups that do not yet have a
3594	 * size classification.
3595	 */
3596	LOOP_UNSET_SIZE_CLASS,
3597
3598	/*
3599	 * Allocate a chunk and then retry the allocation.
3600	 */
3601	LOOP_ALLOC_CHUNK,
3602
3603	/*
3604	 * Ignore the size class restrictions for this allocation.
3605	 */
3606	LOOP_WRONG_SIZE_CLASS,
3607
3608	/*
3609	 * Ignore the empty size, only try to allocate the number of bytes
3610	 * needed for this allocation.
3611	 */
3612	LOOP_NO_EMPTY_SIZE,
3613};
3614
3615static inline void
3616btrfs_lock_block_group(struct btrfs_block_group *cache,
3617		       int delalloc)
3618{
3619	if (delalloc)
3620		down_read(&cache->data_rwsem);
3621}
3622
3623static inline void btrfs_grab_block_group(struct btrfs_block_group *cache,
3624		       int delalloc)
3625{
3626	btrfs_get_block_group(cache);
3627	if (delalloc)
3628		down_read(&cache->data_rwsem);
3629}
3630
3631static struct btrfs_block_group *btrfs_lock_cluster(
3632		   struct btrfs_block_group *block_group,
3633		   struct btrfs_free_cluster *cluster,
3634		   int delalloc)
3635	__acquires(&cluster->refill_lock)
3636{
3637	struct btrfs_block_group *used_bg = NULL;
3638
3639	spin_lock(&cluster->refill_lock);
3640	while (1) {
3641		used_bg = cluster->block_group;
3642		if (!used_bg)
3643			return NULL;
3644
3645		if (used_bg == block_group)
3646			return used_bg;
3647
3648		btrfs_get_block_group(used_bg);
3649
3650		if (!delalloc)
3651			return used_bg;
3652
3653		if (down_read_trylock(&used_bg->data_rwsem))
3654			return used_bg;
3655
3656		spin_unlock(&cluster->refill_lock);
3657
3658		/* We should only have one-level nested. */
3659		down_read_nested(&used_bg->data_rwsem, SINGLE_DEPTH_NESTING);
3660
3661		spin_lock(&cluster->refill_lock);
3662		if (used_bg == cluster->block_group)
3663			return used_bg;
3664
3665		up_read(&used_bg->data_rwsem);
3666		btrfs_put_block_group(used_bg);
3667	}
3668}
3669
3670static inline void
3671btrfs_release_block_group(struct btrfs_block_group *cache,
3672			 int delalloc)
3673{
3674	if (delalloc)
3675		up_read(&cache->data_rwsem);
3676	btrfs_put_block_group(cache);
3677}
3678
3679/*
3680 * Helper function for find_free_extent().
3681 *
3682 * Return -ENOENT to inform caller that we need fallback to unclustered mode.
3683 * Return >0 to inform caller that we find nothing
3684 * Return 0 means we have found a location and set ffe_ctl->found_offset.
3685 */
3686static int find_free_extent_clustered(struct btrfs_block_group *bg,
3687				      struct find_free_extent_ctl *ffe_ctl,
3688				      struct btrfs_block_group **cluster_bg_ret)
3689{
3690	struct btrfs_block_group *cluster_bg;
3691	struct btrfs_free_cluster *last_ptr = ffe_ctl->last_ptr;
3692	u64 aligned_cluster;
3693	u64 offset;
3694	int ret;
3695
3696	cluster_bg = btrfs_lock_cluster(bg, last_ptr, ffe_ctl->delalloc);
3697	if (!cluster_bg)
3698		goto refill_cluster;
3699	if (cluster_bg != bg && (cluster_bg->ro ||
3700	    !block_group_bits(cluster_bg, ffe_ctl->flags)))
3701		goto release_cluster;
3702
3703	offset = btrfs_alloc_from_cluster(cluster_bg, last_ptr,
3704			ffe_ctl->num_bytes, cluster_bg->start,
3705			&ffe_ctl->max_extent_size);
3706	if (offset) {
3707		/* We have a block, we're done */
3708		spin_unlock(&last_ptr->refill_lock);
3709		trace_btrfs_reserve_extent_cluster(cluster_bg, ffe_ctl);
3710		*cluster_bg_ret = cluster_bg;
3711		ffe_ctl->found_offset = offset;
3712		return 0;
3713	}
3714	WARN_ON(last_ptr->block_group != cluster_bg);
3715
3716release_cluster:
3717	/*
3718	 * If we are on LOOP_NO_EMPTY_SIZE, we can't set up a new clusters, so
3719	 * lets just skip it and let the allocator find whatever block it can
3720	 * find. If we reach this point, we will have tried the cluster
3721	 * allocator plenty of times and not have found anything, so we are
3722	 * likely way too fragmented for the clustering stuff to find anything.
3723	 *
3724	 * However, if the cluster is taken from the current block group,
3725	 * release the cluster first, so that we stand a better chance of
3726	 * succeeding in the unclustered allocation.
3727	 */
3728	if (ffe_ctl->loop >= LOOP_NO_EMPTY_SIZE && cluster_bg != bg) {
3729		spin_unlock(&last_ptr->refill_lock);
3730		btrfs_release_block_group(cluster_bg, ffe_ctl->delalloc);
3731		return -ENOENT;
3732	}
3733
3734	/* This cluster didn't work out, free it and start over */
3735	btrfs_return_cluster_to_free_space(NULL, last_ptr);
3736
3737	if (cluster_bg != bg)
3738		btrfs_release_block_group(cluster_bg, ffe_ctl->delalloc);
3739
3740refill_cluster:
3741	if (ffe_ctl->loop >= LOOP_NO_EMPTY_SIZE) {
3742		spin_unlock(&last_ptr->refill_lock);
3743		return -ENOENT;
3744	}
3745
3746	aligned_cluster = max_t(u64,
3747			ffe_ctl->empty_cluster + ffe_ctl->empty_size,
3748			bg->full_stripe_len);
3749	ret = btrfs_find_space_cluster(bg, last_ptr, ffe_ctl->search_start,
3750			ffe_ctl->num_bytes, aligned_cluster);
3751	if (ret == 0) {
3752		/* Now pull our allocation out of this cluster */
3753		offset = btrfs_alloc_from_cluster(bg, last_ptr,
3754				ffe_ctl->num_bytes, ffe_ctl->search_start,
3755				&ffe_ctl->max_extent_size);
3756		if (offset) {
3757			/* We found one, proceed */
3758			spin_unlock(&last_ptr->refill_lock);
3759			ffe_ctl->found_offset = offset;
3760			trace_btrfs_reserve_extent_cluster(bg, ffe_ctl);
3761			return 0;
3762		}
3763	}
3764	/*
3765	 * At this point we either didn't find a cluster or we weren't able to
3766	 * allocate a block from our cluster.  Free the cluster we've been
3767	 * trying to use, and go to the next block group.
3768	 */
3769	btrfs_return_cluster_to_free_space(NULL, last_ptr);
3770	spin_unlock(&last_ptr->refill_lock);
3771	return 1;
3772}
3773
3774/*
3775 * Return >0 to inform caller that we find nothing
3776 * Return 0 when we found an free extent and set ffe_ctrl->found_offset
3777 */
3778static int find_free_extent_unclustered(struct btrfs_block_group *bg,
3779					struct find_free_extent_ctl *ffe_ctl)
3780{
3781	struct btrfs_free_cluster *last_ptr = ffe_ctl->last_ptr;
3782	u64 offset;
3783
3784	/*
3785	 * We are doing an unclustered allocation, set the fragmented flag so
3786	 * we don't bother trying to setup a cluster again until we get more
3787	 * space.
3788	 */
3789	if (unlikely(last_ptr)) {
3790		spin_lock(&last_ptr->lock);
3791		last_ptr->fragmented = 1;
3792		spin_unlock(&last_ptr->lock);
3793	}
3794	if (ffe_ctl->cached) {
3795		struct btrfs_free_space_ctl *free_space_ctl;
3796
3797		free_space_ctl = bg->free_space_ctl;
3798		spin_lock(&free_space_ctl->tree_lock);
3799		if (free_space_ctl->free_space <
3800		    ffe_ctl->num_bytes + ffe_ctl->empty_cluster +
3801		    ffe_ctl->empty_size) {
3802			ffe_ctl->total_free_space = max_t(u64,
3803					ffe_ctl->total_free_space,
3804					free_space_ctl->free_space);
3805			spin_unlock(&free_space_ctl->tree_lock);
3806			return 1;
3807		}
3808		spin_unlock(&free_space_ctl->tree_lock);
3809	}
3810
3811	offset = btrfs_find_space_for_alloc(bg, ffe_ctl->search_start,
3812			ffe_ctl->num_bytes, ffe_ctl->empty_size,
3813			&ffe_ctl->max_extent_size);
3814	if (!offset)
3815		return 1;
3816	ffe_ctl->found_offset = offset;
3817	return 0;
3818}
3819
3820static int do_allocation_clustered(struct btrfs_block_group *block_group,
3821				   struct find_free_extent_ctl *ffe_ctl,
3822				   struct btrfs_block_group **bg_ret)
3823{
3824	int ret;
3825
3826	/* We want to try and use the cluster allocator, so lets look there */
3827	if (ffe_ctl->last_ptr && ffe_ctl->use_cluster) {
3828		ret = find_free_extent_clustered(block_group, ffe_ctl, bg_ret);
3829		if (ret >= 0)
3830			return ret;
3831		/* ret == -ENOENT case falls through */
3832	}
3833
3834	return find_free_extent_unclustered(block_group, ffe_ctl);
3835}
3836
3837/*
3838 * Tree-log block group locking
3839 * ============================
3840 *
3841 * fs_info::treelog_bg_lock protects the fs_info::treelog_bg which
3842 * indicates the starting address of a block group, which is reserved only
3843 * for tree-log metadata.
3844 *
3845 * Lock nesting
3846 * ============
3847 *
3848 * space_info::lock
3849 *   block_group::lock
3850 *     fs_info::treelog_bg_lock
3851 */
3852
3853/*
3854 * Simple allocator for sequential-only block group. It only allows sequential
3855 * allocation. No need to play with trees. This function also reserves the
3856 * bytes as in btrfs_add_reserved_bytes.
3857 */
3858static int do_allocation_zoned(struct btrfs_block_group *block_group,
3859			       struct find_free_extent_ctl *ffe_ctl,
3860			       struct btrfs_block_group **bg_ret)
3861{
3862	struct btrfs_fs_info *fs_info = block_group->fs_info;
3863	struct btrfs_space_info *space_info = block_group->space_info;
3864	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3865	u64 start = block_group->start;
3866	u64 num_bytes = ffe_ctl->num_bytes;
3867	u64 avail;
3868	u64 bytenr = block_group->start;
3869	u64 log_bytenr;
3870	u64 data_reloc_bytenr;
3871	int ret = 0;
3872	bool skip = false;
3873
3874	ASSERT(btrfs_is_zoned(block_group->fs_info));
3875
3876	/*
3877	 * Do not allow non-tree-log blocks in the dedicated tree-log block
3878	 * group, and vice versa.
3879	 */
3880	spin_lock(&fs_info->treelog_bg_lock);
3881	log_bytenr = fs_info->treelog_bg;
3882	if (log_bytenr && ((ffe_ctl->for_treelog && bytenr != log_bytenr) ||
3883			   (!ffe_ctl->for_treelog && bytenr == log_bytenr)))
3884		skip = true;
3885	spin_unlock(&fs_info->treelog_bg_lock);
3886	if (skip)
3887		return 1;
3888
3889	/*
3890	 * Do not allow non-relocation blocks in the dedicated relocation block
3891	 * group, and vice versa.
3892	 */
3893	spin_lock(&fs_info->relocation_bg_lock);
3894	data_reloc_bytenr = fs_info->data_reloc_bg;
3895	if (data_reloc_bytenr &&
3896	    ((ffe_ctl->for_data_reloc && bytenr != data_reloc_bytenr) ||
3897	     (!ffe_ctl->for_data_reloc && bytenr == data_reloc_bytenr)))
3898		skip = true;
3899	spin_unlock(&fs_info->relocation_bg_lock);
3900	if (skip)
3901		return 1;
3902
3903	/* Check RO and no space case before trying to activate it */
3904	spin_lock(&block_group->lock);
3905	if (block_group->ro || btrfs_zoned_bg_is_full(block_group)) {
3906		ret = 1;
3907		/*
3908		 * May need to clear fs_info->{treelog,data_reloc}_bg.
3909		 * Return the error after taking the locks.
3910		 */
3911	}
3912	spin_unlock(&block_group->lock);
3913
3914	/* Metadata block group is activated at write time. */
3915	if (!ret && (block_group->flags & BTRFS_BLOCK_GROUP_DATA) &&
3916	    !btrfs_zone_activate(block_group)) {
3917		ret = 1;
3918		/*
3919		 * May need to clear fs_info->{treelog,data_reloc}_bg.
3920		 * Return the error after taking the locks.
3921		 */
3922	}
3923
3924	spin_lock(&space_info->lock);
3925	spin_lock(&block_group->lock);
3926	spin_lock(&fs_info->treelog_bg_lock);
3927	spin_lock(&fs_info->relocation_bg_lock);
3928
3929	if (ret)
3930		goto out;
3931
3932	ASSERT(!ffe_ctl->for_treelog ||
3933	       block_group->start == fs_info->treelog_bg ||
3934	       fs_info->treelog_bg == 0);
3935	ASSERT(!ffe_ctl->for_data_reloc ||
3936	       block_group->start == fs_info->data_reloc_bg ||
3937	       fs_info->data_reloc_bg == 0);
3938
3939	if (block_group->ro ||
3940	    (!ffe_ctl->for_data_reloc &&
3941	     test_bit(BLOCK_GROUP_FLAG_ZONED_DATA_RELOC, &block_group->runtime_flags))) {
3942		ret = 1;
3943		goto out;
3944	}
3945
3946	/*
3947	 * Do not allow currently using block group to be tree-log dedicated
3948	 * block group.
3949	 */
3950	if (ffe_ctl->for_treelog && !fs_info->treelog_bg &&
3951	    (block_group->used || block_group->reserved)) {
3952		ret = 1;
3953		goto out;
3954	}
3955
3956	/*
3957	 * Do not allow currently used block group to be the data relocation
3958	 * dedicated block group.
3959	 */
3960	if (ffe_ctl->for_data_reloc && !fs_info->data_reloc_bg &&
3961	    (block_group->used || block_group->reserved)) {
3962		ret = 1;
3963		goto out;
3964	}
3965
3966	WARN_ON_ONCE(block_group->alloc_offset > block_group->zone_capacity);
3967	avail = block_group->zone_capacity - block_group->alloc_offset;
3968	if (avail < num_bytes) {
3969		if (ffe_ctl->max_extent_size < avail) {
3970			/*
3971			 * With sequential allocator, free space is always
3972			 * contiguous
3973			 */
3974			ffe_ctl->max_extent_size = avail;
3975			ffe_ctl->total_free_space = avail;
3976		}
3977		ret = 1;
3978		goto out;
3979	}
3980
3981	if (ffe_ctl->for_treelog && !fs_info->treelog_bg)
3982		fs_info->treelog_bg = block_group->start;
3983
3984	if (ffe_ctl->for_data_reloc) {
3985		if (!fs_info->data_reloc_bg)
3986			fs_info->data_reloc_bg = block_group->start;
3987		/*
3988		 * Do not allow allocations from this block group, unless it is
3989		 * for data relocation. Compared to increasing the ->ro, setting
3990		 * the ->zoned_data_reloc_ongoing flag still allows nocow
3991		 * writers to come in. See btrfs_inc_nocow_writers().
3992		 *
3993		 * We need to disable an allocation to avoid an allocation of
3994		 * regular (non-relocation data) extent. With mix of relocation
3995		 * extents and regular extents, we can dispatch WRITE commands
3996		 * (for relocation extents) and ZONE APPEND commands (for
3997		 * regular extents) at the same time to the same zone, which
3998		 * easily break the write pointer.
3999		 *
4000		 * Also, this flag avoids this block group to be zone finished.
4001		 */
4002		set_bit(BLOCK_GROUP_FLAG_ZONED_DATA_RELOC, &block_group->runtime_flags);
4003	}
4004
4005	ffe_ctl->found_offset = start + block_group->alloc_offset;
4006	block_group->alloc_offset += num_bytes;
4007	spin_lock(&ctl->tree_lock);
4008	ctl->free_space -= num_bytes;
4009	spin_unlock(&ctl->tree_lock);
4010
4011	/*
4012	 * We do not check if found_offset is aligned to stripesize. The
4013	 * address is anyway rewritten when using zone append writing.
4014	 */
4015
4016	ffe_ctl->search_start = ffe_ctl->found_offset;
4017
4018out:
4019	if (ret && ffe_ctl->for_treelog)
4020		fs_info->treelog_bg = 0;
4021	if (ret && ffe_ctl->for_data_reloc)
4022		fs_info->data_reloc_bg = 0;
4023	spin_unlock(&fs_info->relocation_bg_lock);
4024	spin_unlock(&fs_info->treelog_bg_lock);
4025	spin_unlock(&block_group->lock);
4026	spin_unlock(&space_info->lock);
4027	return ret;
4028}
4029
4030static int do_allocation(struct btrfs_block_group *block_group,
4031			 struct find_free_extent_ctl *ffe_ctl,
4032			 struct btrfs_block_group **bg_ret)
4033{
4034	switch (ffe_ctl->policy) {
4035	case BTRFS_EXTENT_ALLOC_CLUSTERED:
4036		return do_allocation_clustered(block_group, ffe_ctl, bg_ret);
4037	case BTRFS_EXTENT_ALLOC_ZONED:
4038		return do_allocation_zoned(block_group, ffe_ctl, bg_ret);
4039	default:
4040		BUG();
4041	}
4042}
4043
4044static void release_block_group(struct btrfs_block_group *block_group,
4045				struct find_free_extent_ctl *ffe_ctl,
4046				int delalloc)
4047{
4048	switch (ffe_ctl->policy) {
4049	case BTRFS_EXTENT_ALLOC_CLUSTERED:
4050		ffe_ctl->retry_uncached = false;
4051		break;
4052	case BTRFS_EXTENT_ALLOC_ZONED:
4053		/* Nothing to do */
4054		break;
4055	default:
4056		BUG();
4057	}
4058
4059	BUG_ON(btrfs_bg_flags_to_raid_index(block_group->flags) !=
4060	       ffe_ctl->index);
4061	btrfs_release_block_group(block_group, delalloc);
4062}
4063
4064static void found_extent_clustered(struct find_free_extent_ctl *ffe_ctl,
4065				   struct btrfs_key *ins)
4066{
4067	struct btrfs_free_cluster *last_ptr = ffe_ctl->last_ptr;
4068
4069	if (!ffe_ctl->use_cluster && last_ptr) {
4070		spin_lock(&last_ptr->lock);
4071		last_ptr->window_start = ins->objectid;
4072		spin_unlock(&last_ptr->lock);
4073	}
4074}
4075
4076static void found_extent(struct find_free_extent_ctl *ffe_ctl,
4077			 struct btrfs_key *ins)
4078{
4079	switch (ffe_ctl->policy) {
4080	case BTRFS_EXTENT_ALLOC_CLUSTERED:
4081		found_extent_clustered(ffe_ctl, ins);
4082		break;
4083	case BTRFS_EXTENT_ALLOC_ZONED:
4084		/* Nothing to do */
4085		break;
4086	default:
4087		BUG();
4088	}
4089}
4090
4091static int can_allocate_chunk_zoned(struct btrfs_fs_info *fs_info,
4092				    struct find_free_extent_ctl *ffe_ctl)
4093{
4094	/* Block group's activeness is not a requirement for METADATA block groups. */
4095	if (!(ffe_ctl->flags & BTRFS_BLOCK_GROUP_DATA))
4096		return 0;
4097
4098	/* If we can activate new zone, just allocate a chunk and use it */
4099	if (btrfs_can_activate_zone(fs_info->fs_devices, ffe_ctl->flags))
4100		return 0;
4101
4102	/*
4103	 * We already reached the max active zones. Try to finish one block
4104	 * group to make a room for a new block group. This is only possible
4105	 * for a data block group because btrfs_zone_finish() may need to wait
4106	 * for a running transaction which can cause a deadlock for metadata
4107	 * allocation.
4108	 */
4109	if (ffe_ctl->flags & BTRFS_BLOCK_GROUP_DATA) {
4110		int ret = btrfs_zone_finish_one_bg(fs_info);
4111
4112		if (ret == 1)
4113			return 0;
4114		else if (ret < 0)
4115			return ret;
4116	}
4117
4118	/*
4119	 * If we have enough free space left in an already active block group
4120	 * and we can't activate any other zone now, do not allow allocating a
4121	 * new chunk and let find_free_extent() retry with a smaller size.
4122	 */
4123	if (ffe_ctl->max_extent_size >= ffe_ctl->min_alloc_size)
4124		return -ENOSPC;
4125
4126	/*
4127	 * Even min_alloc_size is not left in any block groups. Since we cannot
4128	 * activate a new block group, allocating it may not help. Let's tell a
4129	 * caller to try again and hope it progress something by writing some
4130	 * parts of the region. That is only possible for data block groups,
4131	 * where a part of the region can be written.
4132	 */
4133	if (ffe_ctl->flags & BTRFS_BLOCK_GROUP_DATA)
4134		return -EAGAIN;
4135
4136	/*
4137	 * We cannot activate a new block group and no enough space left in any
4138	 * block groups. So, allocating a new block group may not help. But,
4139	 * there is nothing to do anyway, so let's go with it.
4140	 */
4141	return 0;
4142}
4143
4144static int can_allocate_chunk(struct btrfs_fs_info *fs_info,
4145			      struct find_free_extent_ctl *ffe_ctl)
4146{
4147	switch (ffe_ctl->policy) {
4148	case BTRFS_EXTENT_ALLOC_CLUSTERED:
4149		return 0;
4150	case BTRFS_EXTENT_ALLOC_ZONED:
4151		return can_allocate_chunk_zoned(fs_info, ffe_ctl);
4152	default:
4153		BUG();
4154	}
4155}
4156
4157/*
4158 * Return >0 means caller needs to re-search for free extent
4159 * Return 0 means we have the needed free extent.
4160 * Return <0 means we failed to locate any free extent.
4161 */
4162static int find_free_extent_update_loop(struct btrfs_fs_info *fs_info,
4163					struct btrfs_key *ins,
4164					struct find_free_extent_ctl *ffe_ctl,
4165					bool full_search)
4166{
4167	struct btrfs_root *root = fs_info->chunk_root;
4168	int ret;
4169
4170	if ((ffe_ctl->loop == LOOP_CACHING_NOWAIT) &&
4171	    ffe_ctl->have_caching_bg && !ffe_ctl->orig_have_caching_bg)
4172		ffe_ctl->orig_have_caching_bg = true;
4173
4174	if (ins->objectid) {
4175		found_extent(ffe_ctl, ins);
4176		return 0;
4177	}
4178
4179	if (ffe_ctl->loop >= LOOP_CACHING_WAIT && ffe_ctl->have_caching_bg)
4180		return 1;
4181
4182	ffe_ctl->index++;
4183	if (ffe_ctl->index < BTRFS_NR_RAID_TYPES)
4184		return 1;
4185
4186	/* See the comments for btrfs_loop_type for an explanation of the phases. */
4187	if (ffe_ctl->loop < LOOP_NO_EMPTY_SIZE) {
4188		ffe_ctl->index = 0;
4189		/*
4190		 * We want to skip the LOOP_CACHING_WAIT step if we don't have
4191		 * any uncached bgs and we've already done a full search
4192		 * through.
4193		 */
4194		if (ffe_ctl->loop == LOOP_CACHING_NOWAIT &&
4195		    (!ffe_ctl->orig_have_caching_bg && full_search))
4196			ffe_ctl->loop++;
4197		ffe_ctl->loop++;
4198
4199		if (ffe_ctl->loop == LOOP_ALLOC_CHUNK) {
4200			struct btrfs_trans_handle *trans;
4201			int exist = 0;
4202
4203			/* Check if allocation policy allows to create a new chunk */
4204			ret = can_allocate_chunk(fs_info, ffe_ctl);
4205			if (ret)
4206				return ret;
4207
4208			trans = current->journal_info;
4209			if (trans)
4210				exist = 1;
4211			else
4212				trans = btrfs_join_transaction(root);
4213
4214			if (IS_ERR(trans)) {
4215				ret = PTR_ERR(trans);
4216				return ret;
4217			}
4218
4219			ret = btrfs_chunk_alloc(trans, ffe_ctl->flags,
4220						CHUNK_ALLOC_FORCE_FOR_EXTENT);
4221
4222			/* Do not bail out on ENOSPC since we can do more. */
4223			if (ret == -ENOSPC) {
4224				ret = 0;
4225				ffe_ctl->loop++;
4226			}
4227			else if (ret < 0)
4228				btrfs_abort_transaction(trans, ret);
4229			else
4230				ret = 0;
4231			if (!exist)
4232				btrfs_end_transaction(trans);
4233			if (ret)
4234				return ret;
4235		}
4236
4237		if (ffe_ctl->loop == LOOP_NO_EMPTY_SIZE) {
4238			if (ffe_ctl->policy != BTRFS_EXTENT_ALLOC_CLUSTERED)
4239				return -ENOSPC;
4240
4241			/*
4242			 * Don't loop again if we already have no empty_size and
4243			 * no empty_cluster.
4244			 */
4245			if (ffe_ctl->empty_size == 0 &&
4246			    ffe_ctl->empty_cluster == 0)
4247				return -ENOSPC;
4248			ffe_ctl->empty_size = 0;
4249			ffe_ctl->empty_cluster = 0;
4250		}
4251		return 1;
4252	}
4253	return -ENOSPC;
4254}
4255
4256static bool find_free_extent_check_size_class(struct find_free_extent_ctl *ffe_ctl,
4257					      struct btrfs_block_group *bg)
4258{
4259	if (ffe_ctl->policy == BTRFS_EXTENT_ALLOC_ZONED)
4260		return true;
4261	if (!btrfs_block_group_should_use_size_class(bg))
4262		return true;
4263	if (ffe_ctl->loop >= LOOP_WRONG_SIZE_CLASS)
4264		return true;
4265	if (ffe_ctl->loop >= LOOP_UNSET_SIZE_CLASS &&
4266	    bg->size_class == BTRFS_BG_SZ_NONE)
4267		return true;
4268	return ffe_ctl->size_class == bg->size_class;
4269}
4270
4271static int prepare_allocation_clustered(struct btrfs_fs_info *fs_info,
4272					struct find_free_extent_ctl *ffe_ctl,
4273					struct btrfs_space_info *space_info,
4274					struct btrfs_key *ins)
4275{
4276	/*
4277	 * If our free space is heavily fragmented we may not be able to make
4278	 * big contiguous allocations, so instead of doing the expensive search
4279	 * for free space, simply return ENOSPC with our max_extent_size so we
4280	 * can go ahead and search for a more manageable chunk.
4281	 *
4282	 * If our max_extent_size is large enough for our allocation simply
4283	 * disable clustering since we will likely not be able to find enough
4284	 * space to create a cluster and induce latency trying.
4285	 */
4286	if (space_info->max_extent_size) {
4287		spin_lock(&space_info->lock);
4288		if (space_info->max_extent_size &&
4289		    ffe_ctl->num_bytes > space_info->max_extent_size) {
4290			ins->offset = space_info->max_extent_size;
4291			spin_unlock(&space_info->lock);
4292			return -ENOSPC;
4293		} else if (space_info->max_extent_size) {
4294			ffe_ctl->use_cluster = false;
4295		}
4296		spin_unlock(&space_info->lock);
4297	}
4298
4299	ffe_ctl->last_ptr = fetch_cluster_info(fs_info, space_info,
4300					       &ffe_ctl->empty_cluster);
4301	if (ffe_ctl->last_ptr) {
4302		struct btrfs_free_cluster *last_ptr = ffe_ctl->last_ptr;
4303
4304		spin_lock(&last_ptr->lock);
4305		if (last_ptr->block_group)
4306			ffe_ctl->hint_byte = last_ptr->window_start;
4307		if (last_ptr->fragmented) {
4308			/*
4309			 * We still set window_start so we can keep track of the
4310			 * last place we found an allocation to try and save
4311			 * some time.
4312			 */
4313			ffe_ctl->hint_byte = last_ptr->window_start;
4314			ffe_ctl->use_cluster = false;
4315		}
4316		spin_unlock(&last_ptr->lock);
4317	}
4318
4319	return 0;
4320}
4321
4322static int prepare_allocation_zoned(struct btrfs_fs_info *fs_info,
4323				    struct find_free_extent_ctl *ffe_ctl)
4324{
4325	if (ffe_ctl->for_treelog) {
4326		spin_lock(&fs_info->treelog_bg_lock);
4327		if (fs_info->treelog_bg)
4328			ffe_ctl->hint_byte = fs_info->treelog_bg;
4329		spin_unlock(&fs_info->treelog_bg_lock);
4330	} else if (ffe_ctl->for_data_reloc) {
4331		spin_lock(&fs_info->relocation_bg_lock);
4332		if (fs_info->data_reloc_bg)
4333			ffe_ctl->hint_byte = fs_info->data_reloc_bg;
4334		spin_unlock(&fs_info->relocation_bg_lock);
4335	} else if (ffe_ctl->flags & BTRFS_BLOCK_GROUP_DATA) {
4336		struct btrfs_block_group *block_group;
4337
4338		spin_lock(&fs_info->zone_active_bgs_lock);
4339		list_for_each_entry(block_group, &fs_info->zone_active_bgs, active_bg_list) {
4340			/*
4341			 * No lock is OK here because avail is monotinically
4342			 * decreasing, and this is just a hint.
4343			 */
4344			u64 avail = block_group->zone_capacity - block_group->alloc_offset;
4345
4346			if (block_group_bits(block_group, ffe_ctl->flags) &&
4347			    avail >= ffe_ctl->num_bytes) {
4348				ffe_ctl->hint_byte = block_group->start;
4349				break;
4350			}
4351		}
4352		spin_unlock(&fs_info->zone_active_bgs_lock);
4353	}
4354
4355	return 0;
4356}
4357
4358static int prepare_allocation(struct btrfs_fs_info *fs_info,
4359			      struct find_free_extent_ctl *ffe_ctl,
4360			      struct btrfs_space_info *space_info,
4361			      struct btrfs_key *ins)
4362{
4363	switch (ffe_ctl->policy) {
4364	case BTRFS_EXTENT_ALLOC_CLUSTERED:
4365		return prepare_allocation_clustered(fs_info, ffe_ctl,
4366						    space_info, ins);
4367	case BTRFS_EXTENT_ALLOC_ZONED:
4368		return prepare_allocation_zoned(fs_info, ffe_ctl);
4369	default:
4370		BUG();
4371	}
4372}
4373
4374/*
4375 * walks the btree of allocated extents and find a hole of a given size.
4376 * The key ins is changed to record the hole:
4377 * ins->objectid == start position
4378 * ins->flags = BTRFS_EXTENT_ITEM_KEY
4379 * ins->offset == the size of the hole.
4380 * Any available blocks before search_start are skipped.
4381 *
4382 * If there is no suitable free space, we will record the max size of
4383 * the free space extent currently.
4384 *
4385 * The overall logic and call chain:
4386 *
4387 * find_free_extent()
4388 * |- Iterate through all block groups
4389 * |  |- Get a valid block group
4390 * |  |- Try to do clustered allocation in that block group
4391 * |  |- Try to do unclustered allocation in that block group
4392 * |  |- Check if the result is valid
4393 * |  |  |- If valid, then exit
4394 * |  |- Jump to next block group
4395 * |
4396 * |- Push harder to find free extents
4397 *    |- If not found, re-iterate all block groups
4398 */
4399static noinline int find_free_extent(struct btrfs_root *root,
4400				     struct btrfs_key *ins,
4401				     struct find_free_extent_ctl *ffe_ctl)
4402{
4403	struct btrfs_fs_info *fs_info = root->fs_info;
4404	int ret = 0;
4405	int cache_block_group_error = 0;
4406	struct btrfs_block_group *block_group = NULL;
4407	struct btrfs_space_info *space_info;
4408	bool full_search = false;
4409
4410	WARN_ON(ffe_ctl->num_bytes < fs_info->sectorsize);
4411
4412	ffe_ctl->search_start = 0;
4413	/* For clustered allocation */
4414	ffe_ctl->empty_cluster = 0;
4415	ffe_ctl->last_ptr = NULL;
4416	ffe_ctl->use_cluster = true;
4417	ffe_ctl->have_caching_bg = false;
4418	ffe_ctl->orig_have_caching_bg = false;
4419	ffe_ctl->index = btrfs_bg_flags_to_raid_index(ffe_ctl->flags);
4420	ffe_ctl->loop = 0;
4421	ffe_ctl->retry_uncached = false;
4422	ffe_ctl->cached = 0;
4423	ffe_ctl->max_extent_size = 0;
4424	ffe_ctl->total_free_space = 0;
4425	ffe_ctl->found_offset = 0;
4426	ffe_ctl->policy = BTRFS_EXTENT_ALLOC_CLUSTERED;
4427	ffe_ctl->size_class = btrfs_calc_block_group_size_class(ffe_ctl->num_bytes);
4428
4429	if (btrfs_is_zoned(fs_info))
4430		ffe_ctl->policy = BTRFS_EXTENT_ALLOC_ZONED;
4431
4432	ins->type = BTRFS_EXTENT_ITEM_KEY;
4433	ins->objectid = 0;
4434	ins->offset = 0;
4435
4436	trace_find_free_extent(root, ffe_ctl);
4437
4438	space_info = btrfs_find_space_info(fs_info, ffe_ctl->flags);
4439	if (!space_info) {
4440		btrfs_err(fs_info, "No space info for %llu", ffe_ctl->flags);
4441		return -ENOSPC;
4442	}
4443
4444	ret = prepare_allocation(fs_info, ffe_ctl, space_info, ins);
4445	if (ret < 0)
4446		return ret;
4447
4448	ffe_ctl->search_start = max(ffe_ctl->search_start,
4449				    first_logical_byte(fs_info));
4450	ffe_ctl->search_start = max(ffe_ctl->search_start, ffe_ctl->hint_byte);
4451	if (ffe_ctl->search_start == ffe_ctl->hint_byte) {
4452		block_group = btrfs_lookup_block_group(fs_info,
4453						       ffe_ctl->search_start);
4454		/*
4455		 * we don't want to use the block group if it doesn't match our
4456		 * allocation bits, or if its not cached.
4457		 *
4458		 * However if we are re-searching with an ideal block group
4459		 * picked out then we don't care that the block group is cached.
4460		 */
4461		if (block_group && block_group_bits(block_group, ffe_ctl->flags) &&
4462		    block_group->cached != BTRFS_CACHE_NO) {
4463			down_read(&space_info->groups_sem);
4464			if (list_empty(&block_group->list) ||
4465			    block_group->ro) {
4466				/*
4467				 * someone is removing this block group,
4468				 * we can't jump into the have_block_group
4469				 * target because our list pointers are not
4470				 * valid
4471				 */
4472				btrfs_put_block_group(block_group);
4473				up_read(&space_info->groups_sem);
4474			} else {
4475				ffe_ctl->index = btrfs_bg_flags_to_raid_index(
4476							block_group->flags);
4477				btrfs_lock_block_group(block_group,
4478						       ffe_ctl->delalloc);
4479				ffe_ctl->hinted = true;
4480				goto have_block_group;
4481			}
4482		} else if (block_group) {
4483			btrfs_put_block_group(block_group);
4484		}
4485	}
4486search:
4487	trace_find_free_extent_search_loop(root, ffe_ctl);
4488	ffe_ctl->have_caching_bg = false;
4489	if (ffe_ctl->index == btrfs_bg_flags_to_raid_index(ffe_ctl->flags) ||
4490	    ffe_ctl->index == 0)
4491		full_search = true;
4492	down_read(&space_info->groups_sem);
4493	list_for_each_entry(block_group,
4494			    &space_info->block_groups[ffe_ctl->index], list) {
4495		struct btrfs_block_group *bg_ret;
4496
4497		ffe_ctl->hinted = false;
4498		/* If the block group is read-only, we can skip it entirely. */
4499		if (unlikely(block_group->ro)) {
4500			if (ffe_ctl->for_treelog)
4501				btrfs_clear_treelog_bg(block_group);
4502			if (ffe_ctl->for_data_reloc)
4503				btrfs_clear_data_reloc_bg(block_group);
4504			continue;
4505		}
4506
4507		btrfs_grab_block_group(block_group, ffe_ctl->delalloc);
4508		ffe_ctl->search_start = block_group->start;
4509
4510		/*
4511		 * this can happen if we end up cycling through all the
4512		 * raid types, but we want to make sure we only allocate
4513		 * for the proper type.
4514		 */
4515		if (!block_group_bits(block_group, ffe_ctl->flags)) {
4516			u64 extra = BTRFS_BLOCK_GROUP_DUP |
4517				BTRFS_BLOCK_GROUP_RAID1_MASK |
4518				BTRFS_BLOCK_GROUP_RAID56_MASK |
4519				BTRFS_BLOCK_GROUP_RAID10;
4520
4521			/*
4522			 * if they asked for extra copies and this block group
4523			 * doesn't provide them, bail.  This does allow us to
4524			 * fill raid0 from raid1.
4525			 */
4526			if ((ffe_ctl->flags & extra) && !(block_group->flags & extra))
4527				goto loop;
4528
4529			/*
4530			 * This block group has different flags than we want.
4531			 * It's possible that we have MIXED_GROUP flag but no
4532			 * block group is mixed.  Just skip such block group.
4533			 */
4534			btrfs_release_block_group(block_group, ffe_ctl->delalloc);
4535			continue;
4536		}
4537
4538have_block_group:
4539		trace_find_free_extent_have_block_group(root, ffe_ctl, block_group);
4540		ffe_ctl->cached = btrfs_block_group_done(block_group);
4541		if (unlikely(!ffe_ctl->cached)) {
4542			ffe_ctl->have_caching_bg = true;
4543			ret = btrfs_cache_block_group(block_group, false);
4544
4545			/*
4546			 * If we get ENOMEM here or something else we want to
4547			 * try other block groups, because it may not be fatal.
4548			 * However if we can't find anything else we need to
4549			 * save our return here so that we return the actual
4550			 * error that caused problems, not ENOSPC.
4551			 */
4552			if (ret < 0) {
4553				if (!cache_block_group_error)
4554					cache_block_group_error = ret;
4555				ret = 0;
4556				goto loop;
4557			}
4558			ret = 0;
4559		}
4560
4561		if (unlikely(block_group->cached == BTRFS_CACHE_ERROR)) {
4562			if (!cache_block_group_error)
4563				cache_block_group_error = -EIO;
4564			goto loop;
4565		}
4566
4567		if (!find_free_extent_check_size_class(ffe_ctl, block_group))
4568			goto loop;
4569
4570		bg_ret = NULL;
4571		ret = do_allocation(block_group, ffe_ctl, &bg_ret);
4572		if (ret > 0)
4573			goto loop;
4574
4575		if (bg_ret && bg_ret != block_group) {
4576			btrfs_release_block_group(block_group, ffe_ctl->delalloc);
4577			block_group = bg_ret;
4578		}
4579
4580		/* Checks */
4581		ffe_ctl->search_start = round_up(ffe_ctl->found_offset,
4582						 fs_info->stripesize);
4583
4584		/* move on to the next group */
4585		if (ffe_ctl->search_start + ffe_ctl->num_bytes >
4586		    block_group->start + block_group->length) {
4587			btrfs_add_free_space_unused(block_group,
4588					    ffe_ctl->found_offset,
4589					    ffe_ctl->num_bytes);
4590			goto loop;
4591		}
4592
4593		if (ffe_ctl->found_offset < ffe_ctl->search_start)
4594			btrfs_add_free_space_unused(block_group,
4595					ffe_ctl->found_offset,
4596					ffe_ctl->search_start - ffe_ctl->found_offset);
4597
4598		ret = btrfs_add_reserved_bytes(block_group, ffe_ctl->ram_bytes,
4599					       ffe_ctl->num_bytes,
4600					       ffe_ctl->delalloc,
4601					       ffe_ctl->loop >= LOOP_WRONG_SIZE_CLASS);
4602		if (ret == -EAGAIN) {
4603			btrfs_add_free_space_unused(block_group,
4604					ffe_ctl->found_offset,
4605					ffe_ctl->num_bytes);
4606			goto loop;
4607		}
4608		btrfs_inc_block_group_reservations(block_group);
4609
4610		/* we are all good, lets return */
4611		ins->objectid = ffe_ctl->search_start;
4612		ins->offset = ffe_ctl->num_bytes;
4613
4614		trace_btrfs_reserve_extent(block_group, ffe_ctl);
4615		btrfs_release_block_group(block_group, ffe_ctl->delalloc);
4616		break;
4617loop:
4618		if (!ffe_ctl->cached && ffe_ctl->loop > LOOP_CACHING_NOWAIT &&
4619		    !ffe_ctl->retry_uncached) {
4620			ffe_ctl->retry_uncached = true;
4621			btrfs_wait_block_group_cache_progress(block_group,
4622						ffe_ctl->num_bytes +
4623						ffe_ctl->empty_cluster +
4624						ffe_ctl->empty_size);
4625			goto have_block_group;
4626		}
4627		release_block_group(block_group, ffe_ctl, ffe_ctl->delalloc);
4628		cond_resched();
4629	}
4630	up_read(&space_info->groups_sem);
4631
4632	ret = find_free_extent_update_loop(fs_info, ins, ffe_ctl, full_search);
4633	if (ret > 0)
4634		goto search;
4635
4636	if (ret == -ENOSPC && !cache_block_group_error) {
4637		/*
4638		 * Use ffe_ctl->total_free_space as fallback if we can't find
4639		 * any contiguous hole.
4640		 */
4641		if (!ffe_ctl->max_extent_size)
4642			ffe_ctl->max_extent_size = ffe_ctl->total_free_space;
4643		spin_lock(&space_info->lock);
4644		space_info->max_extent_size = ffe_ctl->max_extent_size;
4645		spin_unlock(&space_info->lock);
4646		ins->offset = ffe_ctl->max_extent_size;
4647	} else if (ret == -ENOSPC) {
4648		ret = cache_block_group_error;
4649	}
4650	return ret;
4651}
4652
4653/*
4654 * Entry point to the extent allocator. Tries to find a hole that is at least
4655 * as big as @num_bytes.
4656 *
4657 * @root           -	The root that will contain this extent
4658 *
4659 * @ram_bytes      -	The amount of space in ram that @num_bytes take. This
4660 *			is used for accounting purposes. This value differs
4661 *			from @num_bytes only in the case of compressed extents.
4662 *
4663 * @num_bytes      -	Number of bytes to allocate on-disk.
4664 *
4665 * @min_alloc_size -	Indicates the minimum amount of space that the
4666 *			allocator should try to satisfy. In some cases
4667 *			@num_bytes may be larger than what is required and if
4668 *			the filesystem is fragmented then allocation fails.
4669 *			However, the presence of @min_alloc_size gives a
4670 *			chance to try and satisfy the smaller allocation.
4671 *
4672 * @empty_size     -	A hint that you plan on doing more COW. This is the
4673 *			size in bytes the allocator should try to find free
4674 *			next to the block it returns.  This is just a hint and
4675 *			may be ignored by the allocator.
4676 *
4677 * @hint_byte      -	Hint to the allocator to start searching above the byte
4678 *			address passed. It might be ignored.
4679 *
4680 * @ins            -	This key is modified to record the found hole. It will
4681 *			have the following values:
4682 *			ins->objectid == start position
4683 *			ins->flags = BTRFS_EXTENT_ITEM_KEY
4684 *			ins->offset == the size of the hole.
4685 *
4686 * @is_data        -	Boolean flag indicating whether an extent is
4687 *			allocated for data (true) or metadata (false)
4688 *
4689 * @delalloc       -	Boolean flag indicating whether this allocation is for
4690 *			delalloc or not. If 'true' data_rwsem of block groups
4691 *			is going to be acquired.
4692 *
4693 *
4694 * Returns 0 when an allocation succeeded or < 0 when an error occurred. In
4695 * case -ENOSPC is returned then @ins->offset will contain the size of the
4696 * largest available hole the allocator managed to find.
4697 */
4698int btrfs_reserve_extent(struct btrfs_root *root, u64 ram_bytes,
4699			 u64 num_bytes, u64 min_alloc_size,
4700			 u64 empty_size, u64 hint_byte,
4701			 struct btrfs_key *ins, int is_data, int delalloc)
4702{
4703	struct btrfs_fs_info *fs_info = root->fs_info;
4704	struct find_free_extent_ctl ffe_ctl = {};
4705	bool final_tried = num_bytes == min_alloc_size;
4706	u64 flags;
4707	int ret;
4708	bool for_treelog = (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID);
4709	bool for_data_reloc = (btrfs_is_data_reloc_root(root) && is_data);
4710
4711	flags = get_alloc_profile_by_root(root, is_data);
4712again:
4713	WARN_ON(num_bytes < fs_info->sectorsize);
4714
4715	ffe_ctl.ram_bytes = ram_bytes;
4716	ffe_ctl.num_bytes = num_bytes;
4717	ffe_ctl.min_alloc_size = min_alloc_size;
4718	ffe_ctl.empty_size = empty_size;
4719	ffe_ctl.flags = flags;
4720	ffe_ctl.delalloc = delalloc;
4721	ffe_ctl.hint_byte = hint_byte;
4722	ffe_ctl.for_treelog = for_treelog;
4723	ffe_ctl.for_data_reloc = for_data_reloc;
4724
4725	ret = find_free_extent(root, ins, &ffe_ctl);
4726	if (!ret && !is_data) {
4727		btrfs_dec_block_group_reservations(fs_info, ins->objectid);
4728	} else if (ret == -ENOSPC) {
4729		if (!final_tried && ins->offset) {
4730			num_bytes = min(num_bytes >> 1, ins->offset);
4731			num_bytes = round_down(num_bytes,
4732					       fs_info->sectorsize);
4733			num_bytes = max(num_bytes, min_alloc_size);
4734			ram_bytes = num_bytes;
4735			if (num_bytes == min_alloc_size)
4736				final_tried = true;
4737			goto again;
4738		} else if (btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
4739			struct btrfs_space_info *sinfo;
4740
4741			sinfo = btrfs_find_space_info(fs_info, flags);
4742			btrfs_err(fs_info,
4743	"allocation failed flags %llu, wanted %llu tree-log %d, relocation: %d",
4744				  flags, num_bytes, for_treelog, for_data_reloc);
4745			if (sinfo)
4746				btrfs_dump_space_info(fs_info, sinfo,
4747						      num_bytes, 1);
4748		}
4749	}
4750
4751	return ret;
4752}
4753
4754int btrfs_free_reserved_extent(struct btrfs_fs_info *fs_info,
4755			       u64 start, u64 len, int delalloc)
4756{
4757	struct btrfs_block_group *cache;
4758
4759	cache = btrfs_lookup_block_group(fs_info, start);
4760	if (!cache) {
4761		btrfs_err(fs_info, "Unable to find block group for %llu",
4762			  start);
4763		return -ENOSPC;
4764	}
4765
4766	btrfs_add_free_space(cache, start, len);
4767	btrfs_free_reserved_bytes(cache, len, delalloc);
4768	trace_btrfs_reserved_extent_free(fs_info, start, len);
4769
4770	btrfs_put_block_group(cache);
4771	return 0;
4772}
4773
4774int btrfs_pin_reserved_extent(struct btrfs_trans_handle *trans,
4775			      const struct extent_buffer *eb)
4776{
4777	struct btrfs_block_group *cache;
4778	int ret = 0;
4779
4780	cache = btrfs_lookup_block_group(trans->fs_info, eb->start);
4781	if (!cache) {
4782		btrfs_err(trans->fs_info, "unable to find block group for %llu",
4783			  eb->start);
4784		return -ENOSPC;
4785	}
4786
4787	ret = pin_down_extent(trans, cache, eb->start, eb->len, 1);
4788	btrfs_put_block_group(cache);
4789	return ret;
4790}
4791
4792static int alloc_reserved_extent(struct btrfs_trans_handle *trans, u64 bytenr,
4793				 u64 num_bytes)
4794{
4795	struct btrfs_fs_info *fs_info = trans->fs_info;
4796	int ret;
4797
4798	ret = remove_from_free_space_tree(trans, bytenr, num_bytes);
4799	if (ret)
4800		return ret;
4801
4802	ret = btrfs_update_block_group(trans, bytenr, num_bytes, true);
4803	if (ret) {
4804		ASSERT(!ret);
4805		btrfs_err(fs_info, "update block group failed for %llu %llu",
4806			  bytenr, num_bytes);
4807		return ret;
4808	}
4809
4810	trace_btrfs_reserved_extent_alloc(fs_info, bytenr, num_bytes);
4811	return 0;
4812}
4813
4814static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
4815				      u64 parent, u64 root_objectid,
4816				      u64 flags, u64 owner, u64 offset,
4817				      struct btrfs_key *ins, int ref_mod, u64 oref_root)
4818{
4819	struct btrfs_fs_info *fs_info = trans->fs_info;
4820	struct btrfs_root *extent_root;
4821	int ret;
4822	struct btrfs_extent_item *extent_item;
4823	struct btrfs_extent_owner_ref *oref;
4824	struct btrfs_extent_inline_ref *iref;
4825	struct btrfs_path *path;
4826	struct extent_buffer *leaf;
4827	int type;
4828	u32 size;
4829	const bool simple_quota = (btrfs_qgroup_mode(fs_info) == BTRFS_QGROUP_MODE_SIMPLE);
4830
4831	if (parent > 0)
4832		type = BTRFS_SHARED_DATA_REF_KEY;
4833	else
4834		type = BTRFS_EXTENT_DATA_REF_KEY;
4835
4836	size = sizeof(*extent_item);
4837	if (simple_quota)
4838		size += btrfs_extent_inline_ref_size(BTRFS_EXTENT_OWNER_REF_KEY);
4839	size += btrfs_extent_inline_ref_size(type);
4840
4841	path = btrfs_alloc_path();
4842	if (!path)
4843		return -ENOMEM;
4844
4845	extent_root = btrfs_extent_root(fs_info, ins->objectid);
4846	ret = btrfs_insert_empty_item(trans, extent_root, path, ins, size);
4847	if (ret) {
4848		btrfs_free_path(path);
4849		return ret;
4850	}
4851
4852	leaf = path->nodes[0];
4853	extent_item = btrfs_item_ptr(leaf, path->slots[0],
4854				     struct btrfs_extent_item);
4855	btrfs_set_extent_refs(leaf, extent_item, ref_mod);
4856	btrfs_set_extent_generation(leaf, extent_item, trans->transid);
4857	btrfs_set_extent_flags(leaf, extent_item,
4858			       flags | BTRFS_EXTENT_FLAG_DATA);
4859
4860	iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
4861	if (simple_quota) {
4862		btrfs_set_extent_inline_ref_type(leaf, iref, BTRFS_EXTENT_OWNER_REF_KEY);
4863		oref = (struct btrfs_extent_owner_ref *)(&iref->offset);
4864		btrfs_set_extent_owner_ref_root_id(leaf, oref, oref_root);
4865		iref = (struct btrfs_extent_inline_ref *)(oref + 1);
4866	}
4867	btrfs_set_extent_inline_ref_type(leaf, iref, type);
4868
4869	if (parent > 0) {
4870		struct btrfs_shared_data_ref *ref;
4871		ref = (struct btrfs_shared_data_ref *)(iref + 1);
4872		btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
4873		btrfs_set_shared_data_ref_count(leaf, ref, ref_mod);
4874	} else {
4875		struct btrfs_extent_data_ref *ref;
4876		ref = (struct btrfs_extent_data_ref *)(&iref->offset);
4877		btrfs_set_extent_data_ref_root(leaf, ref, root_objectid);
4878		btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
4879		btrfs_set_extent_data_ref_offset(leaf, ref, offset);
4880		btrfs_set_extent_data_ref_count(leaf, ref, ref_mod);
4881	}
4882
4883	btrfs_mark_buffer_dirty(trans, path->nodes[0]);
4884	btrfs_free_path(path);
4885
4886	return alloc_reserved_extent(trans, ins->objectid, ins->offset);
4887}
4888
4889static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
4890				     struct btrfs_delayed_ref_node *node,
4891				     struct btrfs_delayed_extent_op *extent_op)
4892{
4893	struct btrfs_fs_info *fs_info = trans->fs_info;
4894	struct btrfs_root *extent_root;
4895	int ret;
4896	struct btrfs_extent_item *extent_item;
4897	struct btrfs_key extent_key;
4898	struct btrfs_tree_block_info *block_info;
4899	struct btrfs_extent_inline_ref *iref;
4900	struct btrfs_path *path;
4901	struct extent_buffer *leaf;
4902	struct btrfs_delayed_tree_ref *ref;
4903	u32 size = sizeof(*extent_item) + sizeof(*iref);
4904	u64 flags = extent_op->flags_to_set;
 
 
4905	bool skinny_metadata = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
4906
4907	ref = btrfs_delayed_node_to_tree_ref(node);
4908
4909	extent_key.objectid = node->bytenr;
4910	if (skinny_metadata) {
4911		extent_key.offset = ref->level;
 
4912		extent_key.type = BTRFS_METADATA_ITEM_KEY;
4913	} else {
4914		extent_key.offset = node->num_bytes;
4915		extent_key.type = BTRFS_EXTENT_ITEM_KEY;
4916		size += sizeof(*block_info);
4917	}
4918
4919	path = btrfs_alloc_path();
4920	if (!path)
4921		return -ENOMEM;
4922
4923	extent_root = btrfs_extent_root(fs_info, extent_key.objectid);
4924	ret = btrfs_insert_empty_item(trans, extent_root, path, &extent_key,
4925				      size);
4926	if (ret) {
4927		btrfs_free_path(path);
4928		return ret;
4929	}
4930
4931	leaf = path->nodes[0];
4932	extent_item = btrfs_item_ptr(leaf, path->slots[0],
4933				     struct btrfs_extent_item);
4934	btrfs_set_extent_refs(leaf, extent_item, 1);
4935	btrfs_set_extent_generation(leaf, extent_item, trans->transid);
4936	btrfs_set_extent_flags(leaf, extent_item,
4937			       flags | BTRFS_EXTENT_FLAG_TREE_BLOCK);
4938
4939	if (skinny_metadata) {
4940		iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
4941	} else {
4942		block_info = (struct btrfs_tree_block_info *)(extent_item + 1);
4943		btrfs_set_tree_block_key(leaf, block_info, &extent_op->key);
4944		btrfs_set_tree_block_level(leaf, block_info, ref->level);
4945		iref = (struct btrfs_extent_inline_ref *)(block_info + 1);
4946	}
4947
4948	if (node->type == BTRFS_SHARED_BLOCK_REF_KEY) {
4949		btrfs_set_extent_inline_ref_type(leaf, iref,
4950						 BTRFS_SHARED_BLOCK_REF_KEY);
4951		btrfs_set_extent_inline_ref_offset(leaf, iref, ref->parent);
4952	} else {
4953		btrfs_set_extent_inline_ref_type(leaf, iref,
4954						 BTRFS_TREE_BLOCK_REF_KEY);
4955		btrfs_set_extent_inline_ref_offset(leaf, iref, ref->root);
4956	}
4957
4958	btrfs_mark_buffer_dirty(trans, leaf);
4959	btrfs_free_path(path);
4960
4961	return alloc_reserved_extent(trans, node->bytenr, fs_info->nodesize);
4962}
4963
4964int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
4965				     struct btrfs_root *root, u64 owner,
4966				     u64 offset, u64 ram_bytes,
4967				     struct btrfs_key *ins)
4968{
4969	struct btrfs_ref generic_ref = { 0 };
4970	u64 root_objectid = root->root_key.objectid;
4971	u64 owning_root = root_objectid;
 
 
 
 
4972
4973	ASSERT(root_objectid != BTRFS_TREE_LOG_OBJECTID);
4974
4975	if (btrfs_is_data_reloc_root(root) && is_fstree(root->relocation_src_root))
4976		owning_root = root->relocation_src_root;
4977
4978	btrfs_init_generic_ref(&generic_ref, BTRFS_ADD_DELAYED_EXTENT,
4979			       ins->objectid, ins->offset, 0, owning_root);
4980	btrfs_init_data_ref(&generic_ref, root_objectid, owner,
4981			    offset, 0, false);
4982	btrfs_ref_tree_mod(root->fs_info, &generic_ref);
4983
4984	return btrfs_add_delayed_data_ref(trans, &generic_ref, ram_bytes);
4985}
4986
4987/*
4988 * this is used by the tree logging recovery code.  It records that
4989 * an extent has been allocated and makes sure to clear the free
4990 * space cache bits as well
4991 */
4992int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,
4993				   u64 root_objectid, u64 owner, u64 offset,
4994				   struct btrfs_key *ins)
4995{
4996	struct btrfs_fs_info *fs_info = trans->fs_info;
4997	int ret;
4998	struct btrfs_block_group *block_group;
4999	struct btrfs_space_info *space_info;
5000	struct btrfs_squota_delta delta = {
5001		.root = root_objectid,
5002		.num_bytes = ins->offset,
5003		.generation = trans->transid,
5004		.is_data = true,
5005		.is_inc = true,
5006	};
5007
5008	/*
5009	 * Mixed block groups will exclude before processing the log so we only
5010	 * need to do the exclude dance if this fs isn't mixed.
5011	 */
5012	if (!btrfs_fs_incompat(fs_info, MIXED_GROUPS)) {
5013		ret = __exclude_logged_extent(fs_info, ins->objectid,
5014					      ins->offset);
5015		if (ret)
5016			return ret;
5017	}
5018
5019	block_group = btrfs_lookup_block_group(fs_info, ins->objectid);
5020	if (!block_group)
5021		return -EINVAL;
5022
5023	space_info = block_group->space_info;
5024	spin_lock(&space_info->lock);
5025	spin_lock(&block_group->lock);
5026	space_info->bytes_reserved += ins->offset;
5027	block_group->reserved += ins->offset;
5028	spin_unlock(&block_group->lock);
5029	spin_unlock(&space_info->lock);
5030
5031	ret = alloc_reserved_file_extent(trans, 0, root_objectid, 0, owner,
5032					 offset, ins, 1, root_objectid);
5033	if (ret)
5034		btrfs_pin_extent(trans, ins->objectid, ins->offset, 1);
5035	ret = btrfs_record_squota_delta(fs_info, &delta);
5036	btrfs_put_block_group(block_group);
5037	return ret;
5038}
5039
5040#ifdef CONFIG_BTRFS_DEBUG
5041/*
5042 * Extra safety check in case the extent tree is corrupted and extent allocator
5043 * chooses to use a tree block which is already used and locked.
5044 */
5045static bool check_eb_lock_owner(const struct extent_buffer *eb)
5046{
5047	if (eb->lock_owner == current->pid) {
5048		btrfs_err_rl(eb->fs_info,
5049"tree block %llu owner %llu already locked by pid=%d, extent tree corruption detected",
5050			     eb->start, btrfs_header_owner(eb), current->pid);
5051		return true;
5052	}
5053	return false;
5054}
5055#else
5056static bool check_eb_lock_owner(struct extent_buffer *eb)
5057{
5058	return false;
5059}
5060#endif
5061
5062static struct extent_buffer *
5063btrfs_init_new_buffer(struct btrfs_trans_handle *trans, struct btrfs_root *root,
5064		      u64 bytenr, int level, u64 owner,
5065		      enum btrfs_lock_nesting nest)
5066{
5067	struct btrfs_fs_info *fs_info = root->fs_info;
5068	struct extent_buffer *buf;
5069	u64 lockdep_owner = owner;
5070
5071	buf = btrfs_find_create_tree_block(fs_info, bytenr, owner, level);
5072	if (IS_ERR(buf))
5073		return buf;
5074
5075	if (check_eb_lock_owner(buf)) {
5076		free_extent_buffer(buf);
5077		return ERR_PTR(-EUCLEAN);
5078	}
5079
5080	/*
5081	 * The reloc trees are just snapshots, so we need them to appear to be
5082	 * just like any other fs tree WRT lockdep.
5083	 *
5084	 * The exception however is in replace_path() in relocation, where we
5085	 * hold the lock on the original fs root and then search for the reloc
5086	 * root.  At that point we need to make sure any reloc root buffers are
5087	 * set to the BTRFS_TREE_RELOC_OBJECTID lockdep class in order to make
5088	 * lockdep happy.
5089	 */
5090	if (lockdep_owner == BTRFS_TREE_RELOC_OBJECTID &&
5091	    !test_bit(BTRFS_ROOT_RESET_LOCKDEP_CLASS, &root->state))
5092		lockdep_owner = BTRFS_FS_TREE_OBJECTID;
5093
5094	/* btrfs_clear_buffer_dirty() accesses generation field. */
5095	btrfs_set_header_generation(buf, trans->transid);
5096
5097	/*
5098	 * This needs to stay, because we could allocate a freed block from an
5099	 * old tree into a new tree, so we need to make sure this new block is
5100	 * set to the appropriate level and owner.
5101	 */
5102	btrfs_set_buffer_lockdep_class(lockdep_owner, buf, level);
5103
5104	__btrfs_tree_lock(buf, nest);
5105	btrfs_clear_buffer_dirty(trans, buf);
5106	clear_bit(EXTENT_BUFFER_STALE, &buf->bflags);
5107	clear_bit(EXTENT_BUFFER_ZONED_ZEROOUT, &buf->bflags);
5108
5109	set_extent_buffer_uptodate(buf);
5110
5111	memzero_extent_buffer(buf, 0, sizeof(struct btrfs_header));
5112	btrfs_set_header_level(buf, level);
5113	btrfs_set_header_bytenr(buf, buf->start);
5114	btrfs_set_header_generation(buf, trans->transid);
5115	btrfs_set_header_backref_rev(buf, BTRFS_MIXED_BACKREF_REV);
5116	btrfs_set_header_owner(buf, owner);
5117	write_extent_buffer_fsid(buf, fs_info->fs_devices->metadata_uuid);
5118	write_extent_buffer_chunk_tree_uuid(buf, fs_info->chunk_tree_uuid);
5119	if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
5120		buf->log_index = root->log_transid % 2;
5121		/*
5122		 * we allow two log transactions at a time, use different
5123		 * EXTENT bit to differentiate dirty pages.
5124		 */
5125		if (buf->log_index == 0)
5126			set_extent_bit(&root->dirty_log_pages, buf->start,
5127				       buf->start + buf->len - 1,
5128				       EXTENT_DIRTY, NULL);
5129		else
5130			set_extent_bit(&root->dirty_log_pages, buf->start,
5131				       buf->start + buf->len - 1,
5132				       EXTENT_NEW, NULL);
5133	} else {
5134		buf->log_index = -1;
5135		set_extent_bit(&trans->transaction->dirty_pages, buf->start,
5136			       buf->start + buf->len - 1, EXTENT_DIRTY, NULL);
5137	}
5138	/* this returns a buffer locked for blocking */
5139	return buf;
5140}
5141
5142/*
5143 * finds a free extent and does all the dirty work required for allocation
5144 * returns the tree buffer or an ERR_PTR on error.
5145 */
5146struct extent_buffer *btrfs_alloc_tree_block(struct btrfs_trans_handle *trans,
5147					     struct btrfs_root *root,
5148					     u64 parent, u64 root_objectid,
5149					     const struct btrfs_disk_key *key,
5150					     int level, u64 hint,
5151					     u64 empty_size,
5152					     u64 reloc_src_root,
5153					     enum btrfs_lock_nesting nest)
5154{
5155	struct btrfs_fs_info *fs_info = root->fs_info;
5156	struct btrfs_key ins;
5157	struct btrfs_block_rsv *block_rsv;
5158	struct extent_buffer *buf;
5159	struct btrfs_delayed_extent_op *extent_op;
5160	struct btrfs_ref generic_ref = { 0 };
5161	u64 flags = 0;
5162	int ret;
5163	u32 blocksize = fs_info->nodesize;
5164	bool skinny_metadata = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
5165	u64 owning_root;
5166
5167#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
5168	if (btrfs_is_testing(fs_info)) {
5169		buf = btrfs_init_new_buffer(trans, root, root->alloc_bytenr,
5170					    level, root_objectid, nest);
5171		if (!IS_ERR(buf))
5172			root->alloc_bytenr += blocksize;
5173		return buf;
5174	}
5175#endif
5176
5177	block_rsv = btrfs_use_block_rsv(trans, root, blocksize);
5178	if (IS_ERR(block_rsv))
5179		return ERR_CAST(block_rsv);
5180
5181	ret = btrfs_reserve_extent(root, blocksize, blocksize, blocksize,
5182				   empty_size, hint, &ins, 0, 0);
5183	if (ret)
5184		goto out_unuse;
5185
5186	buf = btrfs_init_new_buffer(trans, root, ins.objectid, level,
5187				    root_objectid, nest);
5188	if (IS_ERR(buf)) {
5189		ret = PTR_ERR(buf);
5190		goto out_free_reserved;
5191	}
5192	owning_root = btrfs_header_owner(buf);
5193
5194	if (root_objectid == BTRFS_TREE_RELOC_OBJECTID) {
5195		if (parent == 0)
5196			parent = ins.objectid;
5197		flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF;
5198		owning_root = reloc_src_root;
5199	} else
5200		BUG_ON(parent > 0);
5201
5202	if (root_objectid != BTRFS_TREE_LOG_OBJECTID) {
5203		extent_op = btrfs_alloc_delayed_extent_op();
5204		if (!extent_op) {
5205			ret = -ENOMEM;
5206			goto out_free_buf;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5207		}
5208		if (key)
5209			memcpy(&extent_op->key, key, sizeof(extent_op->key));
5210		else
5211			memset(&extent_op->key, 0, sizeof(extent_op->key));
5212		extent_op->flags_to_set = flags;
5213		extent_op->update_key = skinny_metadata ? false : true;
5214		extent_op->update_flags = true;
5215		extent_op->level = level;
5216
5217		btrfs_init_generic_ref(&generic_ref, BTRFS_ADD_DELAYED_EXTENT,
5218				       ins.objectid, ins.offset, parent, owning_root);
5219		btrfs_init_tree_ref(&generic_ref, level, root_objectid,
5220				    root->root_key.objectid, false);
5221		btrfs_ref_tree_mod(fs_info, &generic_ref);
5222		ret = btrfs_add_delayed_tree_ref(trans, &generic_ref, extent_op);
5223		if (ret)
5224			goto out_free_delayed;
 
 
5225	}
5226	return buf;
5227
5228out_free_delayed:
5229	btrfs_free_delayed_extent_op(extent_op);
5230out_free_buf:
5231	btrfs_tree_unlock(buf);
5232	free_extent_buffer(buf);
5233out_free_reserved:
5234	btrfs_free_reserved_extent(fs_info, ins.objectid, ins.offset, 0);
5235out_unuse:
5236	btrfs_unuse_block_rsv(fs_info, block_rsv, blocksize);
5237	return ERR_PTR(ret);
5238}
5239
5240struct walk_control {
5241	u64 refs[BTRFS_MAX_LEVEL];
5242	u64 flags[BTRFS_MAX_LEVEL];
5243	struct btrfs_key update_progress;
5244	struct btrfs_key drop_progress;
5245	int drop_level;
5246	int stage;
5247	int level;
5248	int shared_level;
5249	int update_ref;
5250	int keep_locks;
5251	int reada_slot;
5252	int reada_count;
5253	int restarted;
 
 
5254};
5255
 
 
 
 
 
5256#define DROP_REFERENCE	1
 
 
 
 
 
 
 
 
5257#define UPDATE_BACKREF	2
5258
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5259static noinline void reada_walk_down(struct btrfs_trans_handle *trans,
5260				     struct btrfs_root *root,
5261				     struct walk_control *wc,
5262				     struct btrfs_path *path)
5263{
5264	struct btrfs_fs_info *fs_info = root->fs_info;
5265	u64 bytenr;
5266	u64 generation;
5267	u64 refs;
5268	u64 flags;
5269	u32 nritems;
5270	struct btrfs_key key;
5271	struct extent_buffer *eb;
5272	int ret;
5273	int slot;
5274	int nread = 0;
5275
5276	if (path->slots[wc->level] < wc->reada_slot) {
5277		wc->reada_count = wc->reada_count * 2 / 3;
5278		wc->reada_count = max(wc->reada_count, 2);
5279	} else {
5280		wc->reada_count = wc->reada_count * 3 / 2;
5281		wc->reada_count = min_t(int, wc->reada_count,
5282					BTRFS_NODEPTRS_PER_BLOCK(fs_info));
5283	}
5284
5285	eb = path->nodes[wc->level];
5286	nritems = btrfs_header_nritems(eb);
5287
5288	for (slot = path->slots[wc->level]; slot < nritems; slot++) {
5289		if (nread >= wc->reada_count)
5290			break;
5291
5292		cond_resched();
5293		bytenr = btrfs_node_blockptr(eb, slot);
5294		generation = btrfs_node_ptr_generation(eb, slot);
5295
5296		if (slot == path->slots[wc->level])
5297			goto reada;
5298
5299		if (wc->stage == UPDATE_BACKREF &&
5300		    generation <= root->root_key.offset)
5301			continue;
5302
5303		/* We don't lock the tree block, it's OK to be racy here */
5304		ret = btrfs_lookup_extent_info(trans, fs_info, bytenr,
5305					       wc->level - 1, 1, &refs,
5306					       &flags, NULL);
5307		/* We don't care about errors in readahead. */
5308		if (ret < 0)
5309			continue;
5310		BUG_ON(refs == 0);
5311
5312		if (wc->stage == DROP_REFERENCE) {
5313			if (refs == 1)
5314				goto reada;
 
 
 
 
 
5315
5316			if (wc->level == 1 &&
5317			    (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
5318				continue;
5319			if (!wc->update_ref ||
5320			    generation <= root->root_key.offset)
5321				continue;
5322			btrfs_node_key_to_cpu(eb, &key, slot);
5323			ret = btrfs_comp_cpu_keys(&key,
5324						  &wc->update_progress);
5325			if (ret < 0)
5326				continue;
5327		} else {
5328			if (wc->level == 1 &&
5329			    (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
5330				continue;
5331		}
5332reada:
5333		btrfs_readahead_node_child(eb, slot);
5334		nread++;
5335	}
5336	wc->reada_slot = slot;
5337}
5338
5339/*
5340 * helper to process tree block while walking down the tree.
5341 *
5342 * when wc->stage == UPDATE_BACKREF, this function updates
5343 * back refs for pointers in the block.
5344 *
5345 * NOTE: return value 1 means we should stop walking down.
5346 */
5347static noinline int walk_down_proc(struct btrfs_trans_handle *trans,
5348				   struct btrfs_root *root,
5349				   struct btrfs_path *path,
5350				   struct walk_control *wc, int lookup_info)
5351{
5352	struct btrfs_fs_info *fs_info = root->fs_info;
5353	int level = wc->level;
5354	struct extent_buffer *eb = path->nodes[level];
5355	u64 flag = BTRFS_BLOCK_FLAG_FULL_BACKREF;
5356	int ret;
5357
5358	if (wc->stage == UPDATE_BACKREF &&
5359	    btrfs_header_owner(eb) != root->root_key.objectid)
5360		return 1;
5361
5362	/*
5363	 * when reference count of tree block is 1, it won't increase
5364	 * again. once full backref flag is set, we never clear it.
5365	 */
5366	if (lookup_info &&
5367	    ((wc->stage == DROP_REFERENCE && wc->refs[level] != 1) ||
5368	     (wc->stage == UPDATE_BACKREF && !(wc->flags[level] & flag)))) {
5369		BUG_ON(!path->locks[level]);
5370		ret = btrfs_lookup_extent_info(trans, fs_info,
5371					       eb->start, level, 1,
5372					       &wc->refs[level],
5373					       &wc->flags[level],
5374					       NULL);
5375		BUG_ON(ret == -ENOMEM);
5376		if (ret)
5377			return ret;
5378		BUG_ON(wc->refs[level] == 0);
 
 
 
 
5379	}
5380
5381	if (wc->stage == DROP_REFERENCE) {
5382		if (wc->refs[level] > 1)
5383			return 1;
5384
5385		if (path->locks[level] && !wc->keep_locks) {
5386			btrfs_tree_unlock_rw(eb, path->locks[level]);
5387			path->locks[level] = 0;
5388		}
5389		return 0;
5390	}
5391
5392	/* wc->stage == UPDATE_BACKREF */
5393	if (!(wc->flags[level] & flag)) {
5394		BUG_ON(!path->locks[level]);
5395		ret = btrfs_inc_ref(trans, root, eb, 1);
5396		BUG_ON(ret); /* -ENOMEM */
 
 
 
5397		ret = btrfs_dec_ref(trans, root, eb, 0);
5398		BUG_ON(ret); /* -ENOMEM */
 
 
 
5399		ret = btrfs_set_disk_extent_flags(trans, eb, flag);
5400		BUG_ON(ret); /* -ENOMEM */
 
 
 
5401		wc->flags[level] |= flag;
5402	}
5403
5404	/*
5405	 * the block is shared by multiple trees, so it's not good to
5406	 * keep the tree lock
5407	 */
5408	if (path->locks[level] && level > 0) {
5409		btrfs_tree_unlock_rw(eb, path->locks[level]);
5410		path->locks[level] = 0;
5411	}
5412	return 0;
5413}
5414
5415/*
5416 * This is used to verify a ref exists for this root to deal with a bug where we
5417 * would have a drop_progress key that hadn't been updated properly.
5418 */
5419static int check_ref_exists(struct btrfs_trans_handle *trans,
5420			    struct btrfs_root *root, u64 bytenr, u64 parent,
5421			    int level)
5422{
 
 
5423	struct btrfs_path *path;
5424	struct btrfs_extent_inline_ref *iref;
5425	int ret;
 
5426
5427	path = btrfs_alloc_path();
5428	if (!path)
5429		return -ENOMEM;
5430
5431	ret = lookup_extent_backref(trans, path, &iref, bytenr,
5432				    root->fs_info->nodesize, parent,
5433				    root->root_key.objectid, level, 0);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5434	btrfs_free_path(path);
5435	if (ret == -ENOENT)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5436		return 0;
5437	if (ret < 0)
 
 
 
 
 
 
 
 
 
 
 
 
5438		return ret;
5439	return 1;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5440}
5441
5442/*
5443 * helper to process tree block pointer.
5444 *
5445 * when wc->stage == DROP_REFERENCE, this function checks
5446 * reference count of the block pointed to. if the block
5447 * is shared and we need update back refs for the subtree
5448 * rooted at the block, this function changes wc->stage to
5449 * UPDATE_BACKREF. if the block is shared and there is no
5450 * need to update back, this function drops the reference
5451 * to the block.
5452 *
5453 * NOTE: return value 1 means we should stop walking down.
5454 */
5455static noinline int do_walk_down(struct btrfs_trans_handle *trans,
5456				 struct btrfs_root *root,
5457				 struct btrfs_path *path,
5458				 struct walk_control *wc, int *lookup_info)
5459{
5460	struct btrfs_fs_info *fs_info = root->fs_info;
5461	u64 bytenr;
5462	u64 generation;
5463	u64 parent;
5464	u64 owner_root = 0;
5465	struct btrfs_tree_parent_check check = { 0 };
5466	struct btrfs_key key;
5467	struct btrfs_ref ref = { 0 };
5468	struct extent_buffer *next;
5469	int level = wc->level;
5470	int reada = 0;
5471	int ret = 0;
5472	bool need_account = false;
5473
5474	generation = btrfs_node_ptr_generation(path->nodes[level],
5475					       path->slots[level]);
5476	/*
5477	 * if the lower level block was created before the snapshot
5478	 * was created, we know there is no need to update back refs
5479	 * for the subtree
5480	 */
5481	if (wc->stage == UPDATE_BACKREF &&
5482	    generation <= root->root_key.offset) {
5483		*lookup_info = 1;
5484		return 1;
5485	}
5486
5487	bytenr = btrfs_node_blockptr(path->nodes[level], path->slots[level]);
5488
5489	check.level = level - 1;
5490	check.transid = generation;
5491	check.owner_root = root->root_key.objectid;
5492	check.has_first_key = true;
5493	btrfs_node_key_to_cpu(path->nodes[level], &check.first_key,
5494			      path->slots[level]);
5495
5496	next = find_extent_buffer(fs_info, bytenr);
5497	if (!next) {
5498		next = btrfs_find_create_tree_block(fs_info, bytenr,
5499				root->root_key.objectid, level - 1);
5500		if (IS_ERR(next))
5501			return PTR_ERR(next);
5502		reada = 1;
5503	}
5504	btrfs_tree_lock(next);
5505
5506	ret = btrfs_lookup_extent_info(trans, fs_info, bytenr, level - 1, 1,
5507				       &wc->refs[level - 1],
5508				       &wc->flags[level - 1],
5509				       &owner_root);
5510	if (ret < 0)
5511		goto out_unlock;
5512
5513	if (unlikely(wc->refs[level - 1] == 0)) {
5514		btrfs_err(fs_info, "Missing references.");
5515		ret = -EIO;
 
5516		goto out_unlock;
5517	}
5518	*lookup_info = 0;
5519
5520	if (wc->stage == DROP_REFERENCE) {
5521		if (wc->refs[level - 1] > 1) {
5522			need_account = true;
5523			if (level == 1 &&
5524			    (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
5525				goto skip;
5526
5527			if (!wc->update_ref ||
5528			    generation <= root->root_key.offset)
5529				goto skip;
5530
5531			btrfs_node_key_to_cpu(path->nodes[level], &key,
5532					      path->slots[level]);
5533			ret = btrfs_comp_cpu_keys(&key, &wc->update_progress);
5534			if (ret < 0)
5535				goto skip;
5536
5537			wc->stage = UPDATE_BACKREF;
5538			wc->shared_level = level - 1;
5539		}
5540	} else {
5541		if (level == 1 &&
5542		    (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
5543			goto skip;
5544	}
5545
5546	if (!btrfs_buffer_uptodate(next, generation, 0)) {
5547		btrfs_tree_unlock(next);
5548		free_extent_buffer(next);
5549		next = NULL;
5550		*lookup_info = 1;
5551	}
5552
5553	if (!next) {
5554		if (reada && level == 1)
5555			reada_walk_down(trans, root, wc, path);
5556		next = read_tree_block(fs_info, bytenr, &check);
5557		if (IS_ERR(next)) {
5558			return PTR_ERR(next);
5559		} else if (!extent_buffer_uptodate(next)) {
5560			free_extent_buffer(next);
5561			return -EIO;
5562		}
5563		btrfs_tree_lock(next);
5564	}
5565
5566	level--;
5567	ASSERT(level == btrfs_header_level(next));
5568	if (level != btrfs_header_level(next)) {
5569		btrfs_err(root->fs_info, "mismatched level");
5570		ret = -EIO;
5571		goto out_unlock;
5572	}
5573	path->nodes[level] = next;
5574	path->slots[level] = 0;
5575	path->locks[level] = BTRFS_WRITE_LOCK;
5576	wc->level = level;
5577	if (wc->level == 1)
5578		wc->reada_slot = 0;
5579	return 0;
5580skip:
 
 
 
5581	wc->refs[level - 1] = 0;
5582	wc->flags[level - 1] = 0;
5583	if (wc->stage == DROP_REFERENCE) {
5584		if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF) {
5585			parent = path->nodes[level]->start;
5586		} else {
5587			ASSERT(root->root_key.objectid ==
5588			       btrfs_header_owner(path->nodes[level]));
5589			if (root->root_key.objectid !=
5590			    btrfs_header_owner(path->nodes[level])) {
5591				btrfs_err(root->fs_info,
5592						"mismatched block owner");
5593				ret = -EIO;
5594				goto out_unlock;
5595			}
5596			parent = 0;
5597		}
5598
5599		/*
5600		 * If we had a drop_progress we need to verify the refs are set
5601		 * as expected.  If we find our ref then we know that from here
5602		 * on out everything should be correct, and we can clear the
5603		 * ->restarted flag.
5604		 */
5605		if (wc->restarted) {
5606			ret = check_ref_exists(trans, root, bytenr, parent,
5607					       level - 1);
5608			if (ret < 0)
5609				goto out_unlock;
5610			if (ret == 0)
5611				goto no_delete;
5612			ret = 0;
5613			wc->restarted = 0;
5614		}
5615
5616		/*
5617		 * Reloc tree doesn't contribute to qgroup numbers, and we have
5618		 * already accounted them at merge time (replace_path),
5619		 * thus we could skip expensive subtree trace here.
5620		 */
5621		if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID &&
5622		    need_account) {
5623			ret = btrfs_qgroup_trace_subtree(trans, next,
5624							 generation, level - 1);
5625			if (ret) {
5626				btrfs_err_rl(fs_info,
5627					     "Error %d accounting shared subtree. Quota is out of sync, rescan required.",
5628					     ret);
5629			}
5630		}
5631
5632		/*
5633		 * We need to update the next key in our walk control so we can
5634		 * update the drop_progress key accordingly.  We don't care if
5635		 * find_next_key doesn't find a key because that means we're at
5636		 * the end and are going to clean up now.
5637		 */
5638		wc->drop_level = level;
5639		find_next_key(path, level, &wc->drop_progress);
5640
5641		btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF, bytenr,
5642				       fs_info->nodesize, parent, owner_root);
5643		btrfs_init_tree_ref(&ref, level - 1, root->root_key.objectid,
5644				    0, false);
5645		ret = btrfs_free_extent(trans, &ref);
5646		if (ret)
5647			goto out_unlock;
5648	}
5649no_delete:
5650	*lookup_info = 1;
5651	ret = 1;
5652
5653out_unlock:
5654	btrfs_tree_unlock(next);
5655	free_extent_buffer(next);
5656
5657	return ret;
5658}
5659
5660/*
5661 * helper to process tree block while walking up the tree.
5662 *
5663 * when wc->stage == DROP_REFERENCE, this function drops
5664 * reference count on the block.
5665 *
5666 * when wc->stage == UPDATE_BACKREF, this function changes
5667 * wc->stage back to DROP_REFERENCE if we changed wc->stage
5668 * to UPDATE_BACKREF previously while processing the block.
5669 *
5670 * NOTE: return value 1 means we should stop walking up.
5671 */
5672static noinline int walk_up_proc(struct btrfs_trans_handle *trans,
5673				 struct btrfs_root *root,
5674				 struct btrfs_path *path,
5675				 struct walk_control *wc)
5676{
5677	struct btrfs_fs_info *fs_info = root->fs_info;
5678	int ret;
5679	int level = wc->level;
5680	struct extent_buffer *eb = path->nodes[level];
5681	u64 parent = 0;
5682
5683	if (wc->stage == UPDATE_BACKREF) {
5684		BUG_ON(wc->shared_level < level);
5685		if (level < wc->shared_level)
5686			goto out;
5687
5688		ret = find_next_key(path, level + 1, &wc->update_progress);
5689		if (ret > 0)
5690			wc->update_ref = 0;
5691
5692		wc->stage = DROP_REFERENCE;
5693		wc->shared_level = -1;
5694		path->slots[level] = 0;
5695
5696		/*
5697		 * check reference count again if the block isn't locked.
5698		 * we should start walking down the tree again if reference
5699		 * count is one.
5700		 */
5701		if (!path->locks[level]) {
5702			BUG_ON(level == 0);
5703			btrfs_tree_lock(eb);
5704			path->locks[level] = BTRFS_WRITE_LOCK;
5705
5706			ret = btrfs_lookup_extent_info(trans, fs_info,
5707						       eb->start, level, 1,
5708						       &wc->refs[level],
5709						       &wc->flags[level],
5710						       NULL);
5711			if (ret < 0) {
5712				btrfs_tree_unlock_rw(eb, path->locks[level]);
5713				path->locks[level] = 0;
5714				return ret;
5715			}
5716			BUG_ON(wc->refs[level] == 0);
 
 
 
 
 
5717			if (wc->refs[level] == 1) {
5718				btrfs_tree_unlock_rw(eb, path->locks[level]);
5719				path->locks[level] = 0;
5720				return 1;
5721			}
5722		}
5723	}
5724
5725	/* wc->stage == DROP_REFERENCE */
5726	BUG_ON(wc->refs[level] > 1 && !path->locks[level]);
5727
5728	if (wc->refs[level] == 1) {
5729		if (level == 0) {
5730			if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
5731				ret = btrfs_dec_ref(trans, root, eb, 1);
5732			else
5733				ret = btrfs_dec_ref(trans, root, eb, 0);
5734			BUG_ON(ret); /* -ENOMEM */
5735			if (is_fstree(root->root_key.objectid)) {
 
 
 
5736				ret = btrfs_qgroup_trace_leaf_items(trans, eb);
5737				if (ret) {
5738					btrfs_err_rl(fs_info,
5739	"error %d accounting leaf items, quota is out of sync, rescan required",
5740					     ret);
5741				}
5742			}
5743		}
5744		/* Make block locked assertion in btrfs_clear_buffer_dirty happy. */
5745		if (!path->locks[level]) {
5746			btrfs_tree_lock(eb);
5747			path->locks[level] = BTRFS_WRITE_LOCK;
5748		}
5749		btrfs_clear_buffer_dirty(trans, eb);
5750	}
5751
5752	if (eb == root->node) {
5753		if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
5754			parent = eb->start;
5755		else if (root->root_key.objectid != btrfs_header_owner(eb))
5756			goto owner_mismatch;
5757	} else {
5758		if (wc->flags[level + 1] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
5759			parent = path->nodes[level + 1]->start;
5760		else if (root->root_key.objectid !=
5761			 btrfs_header_owner(path->nodes[level + 1]))
5762			goto owner_mismatch;
5763	}
5764
5765	btrfs_free_tree_block(trans, btrfs_root_id(root), eb, parent,
5766			      wc->refs[level] == 1);
 
 
5767out:
5768	wc->refs[level] = 0;
5769	wc->flags[level] = 0;
5770	return 0;
5771
5772owner_mismatch:
5773	btrfs_err_rl(fs_info, "unexpected tree owner, have %llu expect %llu",
5774		     btrfs_header_owner(eb), root->root_key.objectid);
5775	return -EUCLEAN;
5776}
5777
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5778static noinline int walk_down_tree(struct btrfs_trans_handle *trans,
5779				   struct btrfs_root *root,
5780				   struct btrfs_path *path,
5781				   struct walk_control *wc)
5782{
5783	int level = wc->level;
5784	int lookup_info = 1;
5785	int ret = 0;
5786
 
5787	while (level >= 0) {
5788		ret = walk_down_proc(trans, root, path, wc, lookup_info);
5789		if (ret)
5790			break;
5791
5792		if (level == 0)
5793			break;
5794
5795		if (path->slots[level] >=
5796		    btrfs_header_nritems(path->nodes[level]))
5797			break;
5798
5799		ret = do_walk_down(trans, root, path, wc, &lookup_info);
5800		if (ret > 0) {
5801			path->slots[level]++;
5802			continue;
5803		} else if (ret < 0)
5804			break;
5805		level = wc->level;
5806	}
5807	return (ret == 1) ? 0 : ret;
5808}
5809
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5810static noinline int walk_up_tree(struct btrfs_trans_handle *trans,
5811				 struct btrfs_root *root,
5812				 struct btrfs_path *path,
5813				 struct walk_control *wc, int max_level)
5814{
5815	int level = wc->level;
5816	int ret;
5817
5818	path->slots[level] = btrfs_header_nritems(path->nodes[level]);
5819	while (level < max_level && path->nodes[level]) {
5820		wc->level = level;
5821		if (path->slots[level] + 1 <
5822		    btrfs_header_nritems(path->nodes[level])) {
5823			path->slots[level]++;
5824			return 0;
5825		} else {
5826			ret = walk_up_proc(trans, root, path, wc);
5827			if (ret > 0)
5828				return 0;
5829			if (ret < 0)
5830				return ret;
5831
5832			if (path->locks[level]) {
5833				btrfs_tree_unlock_rw(path->nodes[level],
5834						     path->locks[level]);
5835				path->locks[level] = 0;
5836			}
5837			free_extent_buffer(path->nodes[level]);
5838			path->nodes[level] = NULL;
5839			level++;
5840		}
5841	}
5842	return 1;
5843}
5844
5845/*
5846 * drop a subvolume tree.
5847 *
5848 * this function traverses the tree freeing any blocks that only
5849 * referenced by the tree.
5850 *
5851 * when a shared tree block is found. this function decreases its
5852 * reference count by one. if update_ref is true, this function
5853 * also make sure backrefs for the shared block and all lower level
5854 * blocks are properly updated.
5855 *
5856 * If called with for_reloc == 0, may exit early with -EAGAIN
5857 */
5858int btrfs_drop_snapshot(struct btrfs_root *root, int update_ref, int for_reloc)
5859{
5860	const bool is_reloc_root = (root->root_key.objectid ==
5861				    BTRFS_TREE_RELOC_OBJECTID);
5862	struct btrfs_fs_info *fs_info = root->fs_info;
5863	struct btrfs_path *path;
5864	struct btrfs_trans_handle *trans;
5865	struct btrfs_root *tree_root = fs_info->tree_root;
5866	struct btrfs_root_item *root_item = &root->root_item;
5867	struct walk_control *wc;
5868	struct btrfs_key key;
5869	int err = 0;
5870	int ret;
5871	int level;
5872	bool root_dropped = false;
5873	bool unfinished_drop = false;
5874
5875	btrfs_debug(fs_info, "Drop subvolume %llu", root->root_key.objectid);
5876
5877	path = btrfs_alloc_path();
5878	if (!path) {
5879		err = -ENOMEM;
5880		goto out;
5881	}
5882
5883	wc = kzalloc(sizeof(*wc), GFP_NOFS);
5884	if (!wc) {
5885		btrfs_free_path(path);
5886		err = -ENOMEM;
5887		goto out;
5888	}
5889
5890	/*
5891	 * Use join to avoid potential EINTR from transaction start. See
5892	 * wait_reserve_ticket and the whole reservation callchain.
5893	 */
5894	if (for_reloc)
5895		trans = btrfs_join_transaction(tree_root);
5896	else
5897		trans = btrfs_start_transaction(tree_root, 0);
5898	if (IS_ERR(trans)) {
5899		err = PTR_ERR(trans);
5900		goto out_free;
5901	}
5902
5903	err = btrfs_run_delayed_items(trans);
5904	if (err)
5905		goto out_end_trans;
5906
5907	/*
5908	 * This will help us catch people modifying the fs tree while we're
5909	 * dropping it.  It is unsafe to mess with the fs tree while it's being
5910	 * dropped as we unlock the root node and parent nodes as we walk down
5911	 * the tree, assuming nothing will change.  If something does change
5912	 * then we'll have stale information and drop references to blocks we've
5913	 * already dropped.
5914	 */
5915	set_bit(BTRFS_ROOT_DELETING, &root->state);
5916	unfinished_drop = test_bit(BTRFS_ROOT_UNFINISHED_DROP, &root->state);
5917
5918	if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
5919		level = btrfs_header_level(root->node);
5920		path->nodes[level] = btrfs_lock_root_node(root);
5921		path->slots[level] = 0;
5922		path->locks[level] = BTRFS_WRITE_LOCK;
5923		memset(&wc->update_progress, 0,
5924		       sizeof(wc->update_progress));
5925	} else {
5926		btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
5927		memcpy(&wc->update_progress, &key,
5928		       sizeof(wc->update_progress));
5929
5930		level = btrfs_root_drop_level(root_item);
5931		BUG_ON(level == 0);
5932		path->lowest_level = level;
5933		ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
5934		path->lowest_level = 0;
5935		if (ret < 0) {
5936			err = ret;
5937			goto out_end_trans;
5938		}
5939		WARN_ON(ret > 0);
 
5940
5941		/*
5942		 * unlock our path, this is safe because only this
5943		 * function is allowed to delete this snapshot
5944		 */
5945		btrfs_unlock_up_safe(path, 0);
5946
5947		level = btrfs_header_level(root->node);
5948		while (1) {
5949			btrfs_tree_lock(path->nodes[level]);
5950			path->locks[level] = BTRFS_WRITE_LOCK;
5951
 
 
 
 
5952			ret = btrfs_lookup_extent_info(trans, fs_info,
5953						path->nodes[level]->start,
5954						level, 1, &wc->refs[level],
5955						&wc->flags[level], NULL);
5956			if (ret < 0) {
5957				err = ret;
5958				goto out_end_trans;
5959			}
5960			BUG_ON(wc->refs[level] == 0);
5961
5962			if (level == btrfs_root_drop_level(root_item))
5963				break;
5964
5965			btrfs_tree_unlock(path->nodes[level]);
5966			path->locks[level] = 0;
5967			WARN_ON(wc->refs[level] != 1);
5968			level--;
5969		}
5970	}
5971
5972	wc->restarted = test_bit(BTRFS_ROOT_DEAD_TREE, &root->state);
5973	wc->level = level;
5974	wc->shared_level = -1;
5975	wc->stage = DROP_REFERENCE;
5976	wc->update_ref = update_ref;
5977	wc->keep_locks = 0;
5978	wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(fs_info);
5979
5980	while (1) {
5981
5982		ret = walk_down_tree(trans, root, path, wc);
5983		if (ret < 0) {
5984			btrfs_abort_transaction(trans, ret);
5985			err = ret;
5986			break;
5987		}
5988
5989		ret = walk_up_tree(trans, root, path, wc, BTRFS_MAX_LEVEL);
5990		if (ret < 0) {
5991			btrfs_abort_transaction(trans, ret);
5992			err = ret;
5993			break;
5994		}
5995
5996		if (ret > 0) {
5997			BUG_ON(wc->stage != DROP_REFERENCE);
 
5998			break;
5999		}
6000
6001		if (wc->stage == DROP_REFERENCE) {
6002			wc->drop_level = wc->level;
6003			btrfs_node_key_to_cpu(path->nodes[wc->drop_level],
6004					      &wc->drop_progress,
6005					      path->slots[wc->drop_level]);
6006		}
6007		btrfs_cpu_key_to_disk(&root_item->drop_progress,
6008				      &wc->drop_progress);
6009		btrfs_set_root_drop_level(root_item, wc->drop_level);
6010
6011		BUG_ON(wc->level == 0);
6012		if (btrfs_should_end_transaction(trans) ||
6013		    (!for_reloc && btrfs_need_cleaner_sleep(fs_info))) {
6014			ret = btrfs_update_root(trans, tree_root,
6015						&root->root_key,
6016						root_item);
6017			if (ret) {
6018				btrfs_abort_transaction(trans, ret);
6019				err = ret;
6020				goto out_end_trans;
6021			}
6022
6023			if (!is_reloc_root)
6024				btrfs_set_last_root_drop_gen(fs_info, trans->transid);
6025
6026			btrfs_end_transaction_throttle(trans);
6027			if (!for_reloc && btrfs_need_cleaner_sleep(fs_info)) {
6028				btrfs_debug(fs_info,
6029					    "drop snapshot early exit");
6030				err = -EAGAIN;
6031				goto out_free;
6032			}
6033
6034		       /*
6035			* Use join to avoid potential EINTR from transaction
6036			* start. See wait_reserve_ticket and the whole
6037			* reservation callchain.
6038			*/
6039			if (for_reloc)
6040				trans = btrfs_join_transaction(tree_root);
6041			else
6042				trans = btrfs_start_transaction(tree_root, 0);
6043			if (IS_ERR(trans)) {
6044				err = PTR_ERR(trans);
6045				goto out_free;
6046			}
6047		}
6048	}
6049	btrfs_release_path(path);
6050	if (err)
6051		goto out_end_trans;
6052
6053	ret = btrfs_del_root(trans, &root->root_key);
6054	if (ret) {
6055		btrfs_abort_transaction(trans, ret);
6056		err = ret;
6057		goto out_end_trans;
6058	}
6059
6060	if (!is_reloc_root) {
6061		ret = btrfs_find_root(tree_root, &root->root_key, path,
6062				      NULL, NULL);
6063		if (ret < 0) {
6064			btrfs_abort_transaction(trans, ret);
6065			err = ret;
6066			goto out_end_trans;
6067		} else if (ret > 0) {
6068			/* if we fail to delete the orphan item this time
 
 
6069			 * around, it'll get picked up the next time.
6070			 *
6071			 * The most common failure here is just -ENOENT.
6072			 */
6073			btrfs_del_orphan_item(trans, tree_root,
6074					      root->root_key.objectid);
6075		}
6076	}
6077
6078	/*
6079	 * This subvolume is going to be completely dropped, and won't be
6080	 * recorded as dirty roots, thus pertrans meta rsv will not be freed at
6081	 * commit transaction time.  So free it here manually.
6082	 */
6083	btrfs_qgroup_convert_reserved_meta(root, INT_MAX);
6084	btrfs_qgroup_free_meta_all_pertrans(root);
6085
6086	if (test_bit(BTRFS_ROOT_IN_RADIX, &root->state))
6087		btrfs_add_dropped_root(trans, root);
6088	else
6089		btrfs_put_root(root);
6090	root_dropped = true;
6091out_end_trans:
6092	if (!is_reloc_root)
6093		btrfs_set_last_root_drop_gen(fs_info, trans->transid);
6094
6095	btrfs_end_transaction_throttle(trans);
6096out_free:
6097	kfree(wc);
6098	btrfs_free_path(path);
6099out:
 
 
 
 
 
 
 
 
6100	/*
6101	 * We were an unfinished drop root, check to see if there are any
6102	 * pending, and if not clear and wake up any waiters.
6103	 */
6104	if (!err && unfinished_drop)
6105		btrfs_maybe_wake_unfinished_drop(fs_info);
6106
6107	/*
6108	 * So if we need to stop dropping the snapshot for whatever reason we
6109	 * need to make sure to add it back to the dead root list so that we
6110	 * keep trying to do the work later.  This also cleans up roots if we
6111	 * don't have it in the radix (like when we recover after a power fail
6112	 * or unmount) so we don't leak memory.
6113	 */
6114	if (!for_reloc && !root_dropped)
6115		btrfs_add_dead_root(root);
6116	return err;
6117}
6118
6119/*
6120 * drop subtree rooted at tree block 'node'.
6121 *
6122 * NOTE: this function will unlock and release tree block 'node'
6123 * only used by relocation code
6124 */
6125int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
6126			struct btrfs_root *root,
6127			struct extent_buffer *node,
6128			struct extent_buffer *parent)
6129{
6130	struct btrfs_fs_info *fs_info = root->fs_info;
6131	struct btrfs_path *path;
6132	struct walk_control *wc;
6133	int level;
6134	int parent_level;
6135	int ret = 0;
6136	int wret;
6137
6138	BUG_ON(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
6139
6140	path = btrfs_alloc_path();
6141	if (!path)
6142		return -ENOMEM;
6143
6144	wc = kzalloc(sizeof(*wc), GFP_NOFS);
6145	if (!wc) {
6146		btrfs_free_path(path);
6147		return -ENOMEM;
6148	}
6149
6150	btrfs_assert_tree_write_locked(parent);
6151	parent_level = btrfs_header_level(parent);
6152	atomic_inc(&parent->refs);
6153	path->nodes[parent_level] = parent;
6154	path->slots[parent_level] = btrfs_header_nritems(parent);
6155
6156	btrfs_assert_tree_write_locked(node);
6157	level = btrfs_header_level(node);
6158	path->nodes[level] = node;
6159	path->slots[level] = 0;
6160	path->locks[level] = BTRFS_WRITE_LOCK;
6161
6162	wc->refs[parent_level] = 1;
6163	wc->flags[parent_level] = BTRFS_BLOCK_FLAG_FULL_BACKREF;
6164	wc->level = level;
6165	wc->shared_level = -1;
6166	wc->stage = DROP_REFERENCE;
6167	wc->update_ref = 0;
6168	wc->keep_locks = 1;
6169	wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(fs_info);
6170
6171	while (1) {
6172		wret = walk_down_tree(trans, root, path, wc);
6173		if (wret < 0) {
6174			ret = wret;
6175			break;
6176		}
6177
6178		wret = walk_up_tree(trans, root, path, wc, parent_level);
6179		if (wret < 0)
6180			ret = wret;
6181		if (wret != 0)
6182			break;
 
6183	}
6184
6185	kfree(wc);
6186	btrfs_free_path(path);
6187	return ret;
6188}
6189
6190/*
6191 * Unpin the extent range in an error context and don't add the space back.
6192 * Errors are not propagated further.
6193 */
6194void btrfs_error_unpin_extent_range(struct btrfs_fs_info *fs_info, u64 start, u64 end)
6195{
6196	unpin_extent_range(fs_info, start, end, false);
6197}
6198
6199/*
6200 * It used to be that old block groups would be left around forever.
6201 * Iterating over them would be enough to trim unused space.  Since we
6202 * now automatically remove them, we also need to iterate over unallocated
6203 * space.
6204 *
6205 * We don't want a transaction for this since the discard may take a
6206 * substantial amount of time.  We don't require that a transaction be
6207 * running, but we do need to take a running transaction into account
6208 * to ensure that we're not discarding chunks that were released or
6209 * allocated in the current transaction.
6210 *
6211 * Holding the chunks lock will prevent other threads from allocating
6212 * or releasing chunks, but it won't prevent a running transaction
6213 * from committing and releasing the memory that the pending chunks
6214 * list head uses.  For that, we need to take a reference to the
6215 * transaction and hold the commit root sem.  We only need to hold
6216 * it while performing the free space search since we have already
6217 * held back allocations.
6218 */
6219static int btrfs_trim_free_extents(struct btrfs_device *device, u64 *trimmed)
6220{
6221	u64 start = BTRFS_DEVICE_RANGE_RESERVED, len = 0, end = 0;
6222	int ret;
6223
6224	*trimmed = 0;
6225
6226	/* Discard not supported = nothing to do. */
6227	if (!bdev_max_discard_sectors(device->bdev))
6228		return 0;
6229
6230	/* Not writable = nothing to do. */
6231	if (!test_bit(BTRFS_DEV_STATE_WRITEABLE, &device->dev_state))
6232		return 0;
6233
6234	/* No free space = nothing to do. */
6235	if (device->total_bytes <= device->bytes_used)
6236		return 0;
6237
6238	ret = 0;
6239
6240	while (1) {
6241		struct btrfs_fs_info *fs_info = device->fs_info;
6242		u64 bytes;
6243
6244		ret = mutex_lock_interruptible(&fs_info->chunk_mutex);
6245		if (ret)
6246			break;
6247
6248		find_first_clear_extent_bit(&device->alloc_state, start,
6249					    &start, &end,
6250					    CHUNK_TRIMMED | CHUNK_ALLOCATED);
6251
6252		/* Check if there are any CHUNK_* bits left */
6253		if (start > device->total_bytes) {
6254			WARN_ON(IS_ENABLED(CONFIG_BTRFS_DEBUG));
6255			btrfs_warn_in_rcu(fs_info,
6256"ignoring attempt to trim beyond device size: offset %llu length %llu device %s device size %llu",
6257					  start, end - start + 1,
6258					  btrfs_dev_name(device),
6259					  device->total_bytes);
6260			mutex_unlock(&fs_info->chunk_mutex);
6261			ret = 0;
6262			break;
6263		}
6264
6265		/* Ensure we skip the reserved space on each device. */
6266		start = max_t(u64, start, BTRFS_DEVICE_RANGE_RESERVED);
6267
6268		/*
6269		 * If find_first_clear_extent_bit find a range that spans the
6270		 * end of the device it will set end to -1, in this case it's up
6271		 * to the caller to trim the value to the size of the device.
6272		 */
6273		end = min(end, device->total_bytes - 1);
6274
6275		len = end - start + 1;
6276
6277		/* We didn't find any extents */
6278		if (!len) {
6279			mutex_unlock(&fs_info->chunk_mutex);
6280			ret = 0;
6281			break;
6282		}
6283
6284		ret = btrfs_issue_discard(device->bdev, start, len,
6285					  &bytes);
6286		if (!ret)
6287			set_extent_bit(&device->alloc_state, start,
6288				       start + bytes - 1, CHUNK_TRIMMED, NULL);
6289		mutex_unlock(&fs_info->chunk_mutex);
6290
6291		if (ret)
6292			break;
6293
6294		start += len;
6295		*trimmed += bytes;
6296
6297		if (fatal_signal_pending(current)) {
6298			ret = -ERESTARTSYS;
6299			break;
6300		}
6301
6302		cond_resched();
6303	}
6304
6305	return ret;
6306}
6307
6308/*
6309 * Trim the whole filesystem by:
6310 * 1) trimming the free space in each block group
6311 * 2) trimming the unallocated space on each device
6312 *
6313 * This will also continue trimming even if a block group or device encounters
6314 * an error.  The return value will be the last error, or 0 if nothing bad
6315 * happens.
6316 */
6317int btrfs_trim_fs(struct btrfs_fs_info *fs_info, struct fstrim_range *range)
6318{
6319	struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
6320	struct btrfs_block_group *cache = NULL;
6321	struct btrfs_device *device;
6322	u64 group_trimmed;
6323	u64 range_end = U64_MAX;
6324	u64 start;
6325	u64 end;
6326	u64 trimmed = 0;
6327	u64 bg_failed = 0;
6328	u64 dev_failed = 0;
6329	int bg_ret = 0;
6330	int dev_ret = 0;
6331	int ret = 0;
6332
6333	if (range->start == U64_MAX)
6334		return -EINVAL;
6335
6336	/*
6337	 * Check range overflow if range->len is set.
6338	 * The default range->len is U64_MAX.
6339	 */
6340	if (range->len != U64_MAX &&
6341	    check_add_overflow(range->start, range->len, &range_end))
6342		return -EINVAL;
6343
6344	cache = btrfs_lookup_first_block_group(fs_info, range->start);
6345	for (; cache; cache = btrfs_next_block_group(cache)) {
6346		if (cache->start >= range_end) {
6347			btrfs_put_block_group(cache);
6348			break;
6349		}
6350
6351		start = max(range->start, cache->start);
6352		end = min(range_end, cache->start + cache->length);
6353
6354		if (end - start >= range->minlen) {
6355			if (!btrfs_block_group_done(cache)) {
6356				ret = btrfs_cache_block_group(cache, true);
6357				if (ret) {
6358					bg_failed++;
6359					bg_ret = ret;
6360					continue;
6361				}
6362			}
6363			ret = btrfs_trim_block_group(cache,
6364						     &group_trimmed,
6365						     start,
6366						     end,
6367						     range->minlen);
6368
6369			trimmed += group_trimmed;
6370			if (ret) {
6371				bg_failed++;
6372				bg_ret = ret;
6373				continue;
6374			}
6375		}
6376	}
6377
6378	if (bg_failed)
6379		btrfs_warn(fs_info,
6380			"failed to trim %llu block group(s), last error %d",
6381			bg_failed, bg_ret);
6382
6383	mutex_lock(&fs_devices->device_list_mutex);
6384	list_for_each_entry(device, &fs_devices->devices, dev_list) {
6385		if (test_bit(BTRFS_DEV_STATE_MISSING, &device->dev_state))
6386			continue;
6387
6388		ret = btrfs_trim_free_extents(device, &group_trimmed);
 
 
6389		if (ret) {
6390			dev_failed++;
6391			dev_ret = ret;
6392			break;
6393		}
6394
6395		trimmed += group_trimmed;
6396	}
6397	mutex_unlock(&fs_devices->device_list_mutex);
6398
6399	if (dev_failed)
6400		btrfs_warn(fs_info,
6401			"failed to trim %llu device(s), last error %d",
6402			dev_failed, dev_ret);
6403	range->len = trimmed;
6404	if (bg_ret)
6405		return bg_ret;
6406	return dev_ret;
6407}