brintos / linux-shallow public Read only

1// SPDX-License-Identifier: GPL-2.02/*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_REFS45 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,50			       struct btrfs_delayed_extent_op *extra_op);51static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,52				    struct extent_buffer *leaf,53				    struct btrfs_extent_item *ei);54static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,55				      u64 parent, u64 root_objectid,56				      u64 flags, u64 owner, u64 offset,57				      struct btrfs_key *ins, int ref_mod, u64 oref_root);58static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,59				     struct btrfs_delayed_ref_node *node,60				     struct btrfs_delayed_extent_op *extent_op);61static int find_next_key(struct btrfs_path *path, int level,62			 struct btrfs_key *key);63 64static int block_group_bits(struct btrfs_block_group *cache, u64 bits)65{66	return (cache->flags & bits) == bits;67}68 69/* simple helper to search for an existing data extent at a given offset */70int btrfs_lookup_data_extent(struct btrfs_fs_info *fs_info, u64 start, u64 len)71{72	struct btrfs_root *root = btrfs_extent_root(fs_info, start);73	int ret;74	struct btrfs_key key;75	struct btrfs_path *path;76 77	path = btrfs_alloc_path();78	if (!path)79		return -ENOMEM;80 81	key.objectid = start;82	key.offset = len;83	key.type = BTRFS_EXTENT_ITEM_KEY;84	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);85	btrfs_free_path(path);86	return ret;87}88 89/*90 * helper function to lookup reference count and flags of a tree block.91 *92 * the head node for delayed ref is used to store the sum of all the93 * reference count modifications queued up in the rbtree. the head94 * node may also store the extent flags to set. This way you can check95 * to see what the reference count and extent flags would be if all of96 * the delayed refs are not processed.97 */98int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans,99			     struct btrfs_fs_info *fs_info, u64 bytenr,100			     u64 offset, int metadata, u64 *refs, u64 *flags,101			     u64 *owning_root)102{103	struct btrfs_root *extent_root;104	struct btrfs_delayed_ref_head *head;105	struct btrfs_delayed_ref_root *delayed_refs;106	struct btrfs_path *path;107	struct btrfs_key key;108	u64 num_refs;109	u64 extent_flags;110	u64 owner = 0;111	int ret;112 113	/*114	 * If we don't have skinny metadata, don't bother doing anything115	 * different116	 */117	if (metadata && !btrfs_fs_incompat(fs_info, SKINNY_METADATA)) {118		offset = fs_info->nodesize;119		metadata = 0;120	}121 122	path = btrfs_alloc_path();123	if (!path)124		return -ENOMEM;125 126search_again:127	key.objectid = bytenr;128	key.offset = offset;129	if (metadata)130		key.type = BTRFS_METADATA_ITEM_KEY;131	else132		key.type = BTRFS_EXTENT_ITEM_KEY;133 134	extent_root = btrfs_extent_root(fs_info, bytenr);135	ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);136	if (ret < 0)137		goto out_free;138 139	if (ret > 0 && key.type == BTRFS_METADATA_ITEM_KEY) {140		if (path->slots[0]) {141			path->slots[0]--;142			btrfs_item_key_to_cpu(path->nodes[0], &key,143					      path->slots[0]);144			if (key.objectid == bytenr &&145			    key.type == BTRFS_EXTENT_ITEM_KEY &&146			    key.offset == fs_info->nodesize)147				ret = 0;148		}149	}150 151	if (ret == 0) {152		struct extent_buffer *leaf = path->nodes[0];153		struct btrfs_extent_item *ei;154		const u32 item_size = btrfs_item_size(leaf, path->slots[0]);155 156		if (unlikely(item_size < sizeof(*ei))) {157			ret = -EUCLEAN;158			btrfs_err(fs_info,159			"unexpected extent item size, has %u expect >= %zu",160				  item_size, sizeof(*ei));161			btrfs_abort_transaction(trans, ret);162			goto out_free;163		}164 165		ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);166		num_refs = btrfs_extent_refs(leaf, ei);167		if (unlikely(num_refs == 0)) {168			ret = -EUCLEAN;169			btrfs_err(fs_info,170		"unexpected zero reference count for extent item (%llu %u %llu)",171				  key.objectid, key.type, key.offset);172			btrfs_abort_transaction(trans, ret);173			goto out_free;174		}175		extent_flags = btrfs_extent_flags(leaf, ei);176		owner = btrfs_get_extent_owner_root(fs_info, leaf, path->slots[0]);177	} else {178		num_refs = 0;179		extent_flags = 0;180		ret = 0;181	}182 183	delayed_refs = &trans->transaction->delayed_refs;184	spin_lock(&delayed_refs->lock);185	head = btrfs_find_delayed_ref_head(delayed_refs, bytenr);186	if (head) {187		if (!mutex_trylock(&head->mutex)) {188			refcount_inc(&head->refs);189			spin_unlock(&delayed_refs->lock);190 191			btrfs_release_path(path);192 193			/*194			 * Mutex was contended, block until it's released and try195			 * again196			 */197			mutex_lock(&head->mutex);198			mutex_unlock(&head->mutex);199			btrfs_put_delayed_ref_head(head);200			goto search_again;201		}202		spin_lock(&head->lock);203		if (head->extent_op && head->extent_op->update_flags)204			extent_flags |= head->extent_op->flags_to_set;205 206		num_refs += head->ref_mod;207		spin_unlock(&head->lock);208		mutex_unlock(&head->mutex);209	}210	spin_unlock(&delayed_refs->lock);211 212	WARN_ON(num_refs == 0);213	if (refs)214		*refs = num_refs;215	if (flags)216		*flags = extent_flags;217	if (owning_root)218		*owning_root = owner;219out_free:220	btrfs_free_path(path);221	return ret;222}223 224/*225 * Back reference rules.  Back refs have three main goals:226 *227 * 1) differentiate between all holders of references to an extent so that228 *    when a reference is dropped we can make sure it was a valid reference229 *    before freeing the extent.230 *231 * 2) Provide enough information to quickly find the holders of an extent232 *    if we notice a given block is corrupted or bad.233 *234 * 3) Make it easy to migrate blocks for FS shrinking or storage pool235 *    maintenance.  This is actually the same as #2, but with a slightly236 *    different use case.237 *238 * There are two kinds of back refs. The implicit back refs is optimized239 * for pointers in non-shared tree blocks. For a given pointer in a block,240 * back refs of this kind provide information about the block's owner tree241 * and the pointer's key. These information allow us to find the block by242 * b-tree searching. The full back refs is for pointers in tree blocks not243 * referenced by their owner trees. The location of tree block is recorded244 * in the back refs. Actually the full back refs is generic, and can be245 * used in all cases the implicit back refs is used. The major shortcoming246 * of the full back refs is its overhead. Every time a tree block gets247 * COWed, we have to update back refs entry for all pointers in it.248 *249 * For a newly allocated tree block, we use implicit back refs for250 * pointers in it. This means most tree related operations only involve251 * implicit back refs. For a tree block created in old transaction, the252 * only way to drop a reference to it is COW it. So we can detect the253 * event that tree block loses its owner tree's reference and do the254 * back refs conversion.255 *256 * When a tree block is COWed through a tree, there are four cases:257 *258 * The reference count of the block is one and the tree is the block's259 * owner tree. Nothing to do in this case.260 *261 * The reference count of the block is one and the tree is not the262 * block's owner tree. In this case, full back refs is used for pointers263 * in the block. Remove these full back refs, add implicit back refs for264 * every pointers in the new block.265 *266 * The reference count of the block is greater than one and the tree is267 * the block's owner tree. In this case, implicit back refs is used for268 * pointers in the block. Add full back refs for every pointers in the269 * block, increase lower level extents' reference counts. The original270 * implicit back refs are entailed to the new block.271 *272 * The reference count of the block is greater than one and the tree is273 * not the block's owner tree. Add implicit back refs for every pointer in274 * the new block, increase lower level extents' reference count.275 *276 * Back Reference Key composing:277 *278 * The key objectid corresponds to the first byte in the extent,279 * The key type is used to differentiate between types of back refs.280 * There are different meanings of the key offset for different types281 * of back refs.282 *283 * File extents can be referenced by:284 *285 * - multiple snapshots, subvolumes, or different generations in one subvol286 * - different files inside a single subvolume287 * - different offsets inside a file (bookend extents in file.c)288 *289 * The extent ref structure for the implicit back refs has fields for:290 *291 * - Objectid of the subvolume root292 * - objectid of the file holding the reference293 * - original offset in the file294 * - how many bookend extents295 *296 * The key offset for the implicit back refs is hash of the first297 * three fields.298 *299 * The extent ref structure for the full back refs has field for:300 *301 * - number of pointers in the tree leaf302 *303 * The key offset for the implicit back refs is the first byte of304 * the tree leaf305 *306 * When a file extent is allocated, The implicit back refs is used.307 * the fields are filled in:308 *309 *     (root_key.objectid, inode objectid, offset in file, 1)310 *311 * When a file extent is removed file truncation, we find the312 * corresponding implicit back refs and check the following fields:313 *314 *     (btrfs_header_owner(leaf), inode objectid, offset in file)315 *316 * Btree extents can be referenced by:317 *318 * - Different subvolumes319 *320 * Both the implicit back refs and the full back refs for tree blocks321 * only consist of key. The key offset for the implicit back refs is322 * objectid of block's owner tree. The key offset for the full back refs323 * is the first byte of parent block.324 *325 * When implicit back refs is used, information about the lowest key and326 * level of the tree block are required. These information are stored in327 * tree block info structure.328 */329 330/*331 * is_data == BTRFS_REF_TYPE_BLOCK, tree block type is required,332 * is_data == BTRFS_REF_TYPE_DATA, data type is requiried,333 * is_data == BTRFS_REF_TYPE_ANY, either type is OK.334 */335int btrfs_get_extent_inline_ref_type(const struct extent_buffer *eb,336				     struct btrfs_extent_inline_ref *iref,337				     enum btrfs_inline_ref_type is_data)338{339	struct btrfs_fs_info *fs_info = eb->fs_info;340	int type = btrfs_extent_inline_ref_type(eb, iref);341	u64 offset = btrfs_extent_inline_ref_offset(eb, iref);342 343	if (type == BTRFS_EXTENT_OWNER_REF_KEY) {344		ASSERT(btrfs_fs_incompat(fs_info, SIMPLE_QUOTA));345		return type;346	}347 348	if (type == BTRFS_TREE_BLOCK_REF_KEY ||349	    type == BTRFS_SHARED_BLOCK_REF_KEY ||350	    type == BTRFS_SHARED_DATA_REF_KEY ||351	    type == BTRFS_EXTENT_DATA_REF_KEY) {352		if (is_data == BTRFS_REF_TYPE_BLOCK) {353			if (type == BTRFS_TREE_BLOCK_REF_KEY)354				return type;355			if (type == BTRFS_SHARED_BLOCK_REF_KEY) {356				ASSERT(fs_info);357				/*358				 * Every shared one has parent tree block,359				 * which must be aligned to sector size.360				 */361				if (offset && IS_ALIGNED(offset, fs_info->sectorsize))362					return type;363			}364		} else if (is_data == BTRFS_REF_TYPE_DATA) {365			if (type == BTRFS_EXTENT_DATA_REF_KEY)366				return type;367			if (type == BTRFS_SHARED_DATA_REF_KEY) {368				ASSERT(fs_info);369				/*370				 * Every shared one has parent tree block,371				 * which must be aligned to sector size.372				 */373				if (offset &&374				    IS_ALIGNED(offset, fs_info->sectorsize))375					return type;376			}377		} else {378			ASSERT(is_data == BTRFS_REF_TYPE_ANY);379			return type;380		}381	}382 383	WARN_ON(1);384	btrfs_print_leaf(eb);385	btrfs_err(fs_info,386		  "eb %llu iref 0x%lx invalid extent inline ref type %d",387		  eb->start, (unsigned long)iref, type);388 389	return BTRFS_REF_TYPE_INVALID;390}391 392u64 hash_extent_data_ref(u64 root_objectid, u64 owner, u64 offset)393{394	u32 high_crc = ~(u32)0;395	u32 low_crc = ~(u32)0;396	__le64 lenum;397 398	lenum = cpu_to_le64(root_objectid);399	high_crc = crc32c(high_crc, &lenum, sizeof(lenum));400	lenum = cpu_to_le64(owner);401	low_crc = crc32c(low_crc, &lenum, sizeof(lenum));402	lenum = cpu_to_le64(offset);403	low_crc = crc32c(low_crc, &lenum, sizeof(lenum));404 405	return ((u64)high_crc << 31) ^ (u64)low_crc;406}407 408static u64 hash_extent_data_ref_item(struct extent_buffer *leaf,409				     struct btrfs_extent_data_ref *ref)410{411	return hash_extent_data_ref(btrfs_extent_data_ref_root(leaf, ref),412				    btrfs_extent_data_ref_objectid(leaf, ref),413				    btrfs_extent_data_ref_offset(leaf, ref));414}415 416static int match_extent_data_ref(struct extent_buffer *leaf,417				 struct btrfs_extent_data_ref *ref,418				 u64 root_objectid, u64 owner, u64 offset)419{420	if (btrfs_extent_data_ref_root(leaf, ref) != root_objectid ||421	    btrfs_extent_data_ref_objectid(leaf, ref) != owner ||422	    btrfs_extent_data_ref_offset(leaf, ref) != offset)423		return 0;424	return 1;425}426 427static noinline int lookup_extent_data_ref(struct btrfs_trans_handle *trans,428					   struct btrfs_path *path,429					   u64 bytenr, u64 parent,430					   u64 root_objectid,431					   u64 owner, u64 offset)432{433	struct btrfs_root *root = btrfs_extent_root(trans->fs_info, bytenr);434	struct btrfs_key key;435	struct btrfs_extent_data_ref *ref;436	struct extent_buffer *leaf;437	u32 nritems;438	int recow;439	int ret;440 441	key.objectid = bytenr;442	if (parent) {443		key.type = BTRFS_SHARED_DATA_REF_KEY;444		key.offset = parent;445	} else {446		key.type = BTRFS_EXTENT_DATA_REF_KEY;447		key.offset = hash_extent_data_ref(root_objectid,448						  owner, offset);449	}450again:451	recow = 0;452	ret = btrfs_search_slot(trans, root, &key, path, -1, 1);453	if (ret < 0)454		return ret;455 456	if (parent) {457		if (ret)458			return -ENOENT;459		return 0;460	}461 462	ret = -ENOENT;463	leaf = path->nodes[0];464	nritems = btrfs_header_nritems(leaf);465	while (1) {466		if (path->slots[0] >= nritems) {467			ret = btrfs_next_leaf(root, path);468			if (ret) {469				if (ret > 0)470					return -ENOENT;471				return ret;472			}473 474			leaf = path->nodes[0];475			nritems = btrfs_header_nritems(leaf);476			recow = 1;477		}478 479		btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);480		if (key.objectid != bytenr ||481		    key.type != BTRFS_EXTENT_DATA_REF_KEY)482			goto fail;483 484		ref = btrfs_item_ptr(leaf, path->slots[0],485				     struct btrfs_extent_data_ref);486 487		if (match_extent_data_ref(leaf, ref, root_objectid,488					  owner, offset)) {489			if (recow) {490				btrfs_release_path(path);491				goto again;492			}493			ret = 0;494			break;495		}496		path->slots[0]++;497	}498fail:499	return ret;500}501 502static noinline int insert_extent_data_ref(struct btrfs_trans_handle *trans,503					   struct btrfs_path *path,504					   struct btrfs_delayed_ref_node *node,505					   u64 bytenr)506{507	struct btrfs_root *root = btrfs_extent_root(trans->fs_info, bytenr);508	struct btrfs_key key;509	struct extent_buffer *leaf;510	u64 owner = btrfs_delayed_ref_owner(node);511	u64 offset = btrfs_delayed_ref_offset(node);512	u32 size;513	u32 num_refs;514	int ret;515 516	key.objectid = bytenr;517	if (node->parent) {518		key.type = BTRFS_SHARED_DATA_REF_KEY;519		key.offset = node->parent;520		size = sizeof(struct btrfs_shared_data_ref);521	} else {522		key.type = BTRFS_EXTENT_DATA_REF_KEY;523		key.offset = hash_extent_data_ref(node->ref_root, owner, offset);524		size = sizeof(struct btrfs_extent_data_ref);525	}526 527	ret = btrfs_insert_empty_item(trans, root, path, &key, size);528	if (ret && ret != -EEXIST)529		goto fail;530 531	leaf = path->nodes[0];532	if (node->parent) {533		struct btrfs_shared_data_ref *ref;534		ref = btrfs_item_ptr(leaf, path->slots[0],535				     struct btrfs_shared_data_ref);536		if (ret == 0) {537			btrfs_set_shared_data_ref_count(leaf, ref, node->ref_mod);538		} else {539			num_refs = btrfs_shared_data_ref_count(leaf, ref);540			num_refs += node->ref_mod;541			btrfs_set_shared_data_ref_count(leaf, ref, num_refs);542		}543	} else {544		struct btrfs_extent_data_ref *ref;545		while (ret == -EEXIST) {546			ref = btrfs_item_ptr(leaf, path->slots[0],547					     struct btrfs_extent_data_ref);548			if (match_extent_data_ref(leaf, ref, node->ref_root,549						  owner, offset))550				break;551			btrfs_release_path(path);552			key.offset++;553			ret = btrfs_insert_empty_item(trans, root, path, &key,554						      size);555			if (ret && ret != -EEXIST)556				goto fail;557 558			leaf = path->nodes[0];559		}560		ref = btrfs_item_ptr(leaf, path->slots[0],561				     struct btrfs_extent_data_ref);562		if (ret == 0) {563			btrfs_set_extent_data_ref_root(leaf, ref, node->ref_root);564			btrfs_set_extent_data_ref_objectid(leaf, ref, owner);565			btrfs_set_extent_data_ref_offset(leaf, ref, offset);566			btrfs_set_extent_data_ref_count(leaf, ref, node->ref_mod);567		} else {568			num_refs = btrfs_extent_data_ref_count(leaf, ref);569			num_refs += node->ref_mod;570			btrfs_set_extent_data_ref_count(leaf, ref, num_refs);571		}572	}573	btrfs_mark_buffer_dirty(trans, leaf);574	ret = 0;575fail:576	btrfs_release_path(path);577	return ret;578}579 580static noinline int remove_extent_data_ref(struct btrfs_trans_handle *trans,581					   struct btrfs_root *root,582					   struct btrfs_path *path,583					   int refs_to_drop)584{585	struct btrfs_key key;586	struct btrfs_extent_data_ref *ref1 = NULL;587	struct btrfs_shared_data_ref *ref2 = NULL;588	struct extent_buffer *leaf;589	u32 num_refs = 0;590	int ret = 0;591 592	leaf = path->nodes[0];593	btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);594 595	if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {596		ref1 = btrfs_item_ptr(leaf, path->slots[0],597				      struct btrfs_extent_data_ref);598		num_refs = btrfs_extent_data_ref_count(leaf, ref1);599	} else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {600		ref2 = btrfs_item_ptr(leaf, path->slots[0],601				      struct btrfs_shared_data_ref);602		num_refs = btrfs_shared_data_ref_count(leaf, ref2);603	} else {604		btrfs_err(trans->fs_info,605			  "unrecognized backref key (%llu %u %llu)",606			  key.objectid, key.type, key.offset);607		btrfs_abort_transaction(trans, -EUCLEAN);608		return -EUCLEAN;609	}610 611	BUG_ON(num_refs < refs_to_drop);612	num_refs -= refs_to_drop;613 614	if (num_refs == 0) {615		ret = btrfs_del_item(trans, root, path);616	} else {617		if (key.type == BTRFS_EXTENT_DATA_REF_KEY)618			btrfs_set_extent_data_ref_count(leaf, ref1, num_refs);619		else if (key.type == BTRFS_SHARED_DATA_REF_KEY)620			btrfs_set_shared_data_ref_count(leaf, ref2, num_refs);621		btrfs_mark_buffer_dirty(trans, leaf);622	}623	return ret;624}625 626static noinline u32 extent_data_ref_count(struct btrfs_path *path,627					  struct btrfs_extent_inline_ref *iref)628{629	struct btrfs_key key;630	struct extent_buffer *leaf;631	struct btrfs_extent_data_ref *ref1;632	struct btrfs_shared_data_ref *ref2;633	u32 num_refs = 0;634	int type;635 636	leaf = path->nodes[0];637	btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);638 639	if (iref) {640		/*641		 * If type is invalid, we should have bailed out earlier than642		 * this call.643		 */644		type = btrfs_get_extent_inline_ref_type(leaf, iref, BTRFS_REF_TYPE_DATA);645		ASSERT(type != BTRFS_REF_TYPE_INVALID);646		if (type == BTRFS_EXTENT_DATA_REF_KEY) {647			ref1 = (struct btrfs_extent_data_ref *)(&iref->offset);648			num_refs = btrfs_extent_data_ref_count(leaf, ref1);649		} else {650			ref2 = (struct btrfs_shared_data_ref *)(iref + 1);651			num_refs = btrfs_shared_data_ref_count(leaf, ref2);652		}653	} else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {654		ref1 = btrfs_item_ptr(leaf, path->slots[0],655				      struct btrfs_extent_data_ref);656		num_refs = btrfs_extent_data_ref_count(leaf, ref1);657	} else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {658		ref2 = btrfs_item_ptr(leaf, path->slots[0],659				      struct btrfs_shared_data_ref);660		num_refs = btrfs_shared_data_ref_count(leaf, ref2);661	} else {662		WARN_ON(1);663	}664	return num_refs;665}666 667static noinline int lookup_tree_block_ref(struct btrfs_trans_handle *trans,668					  struct btrfs_path *path,669					  u64 bytenr, u64 parent,670					  u64 root_objectid)671{672	struct btrfs_root *root = btrfs_extent_root(trans->fs_info, bytenr);673	struct btrfs_key key;674	int ret;675 676	key.objectid = bytenr;677	if (parent) {678		key.type = BTRFS_SHARED_BLOCK_REF_KEY;679		key.offset = parent;680	} else {681		key.type = BTRFS_TREE_BLOCK_REF_KEY;682		key.offset = root_objectid;683	}684 685	ret = btrfs_search_slot(trans, root, &key, path, -1, 1);686	if (ret > 0)687		ret = -ENOENT;688	return ret;689}690 691static noinline int insert_tree_block_ref(struct btrfs_trans_handle *trans,692					  struct btrfs_path *path,693					  struct btrfs_delayed_ref_node *node,694					  u64 bytenr)695{696	struct btrfs_root *root = btrfs_extent_root(trans->fs_info, bytenr);697	struct btrfs_key key;698	int ret;699 700	key.objectid = bytenr;701	if (node->parent) {702		key.type = BTRFS_SHARED_BLOCK_REF_KEY;703		key.offset = node->parent;704	} else {705		key.type = BTRFS_TREE_BLOCK_REF_KEY;706		key.offset = node->ref_root;707	}708 709	ret = btrfs_insert_empty_item(trans, root, path, &key, 0);710	btrfs_release_path(path);711	return ret;712}713 714static inline int extent_ref_type(u64 parent, u64 owner)715{716	int type;717	if (owner < BTRFS_FIRST_FREE_OBJECTID) {718		if (parent > 0)719			type = BTRFS_SHARED_BLOCK_REF_KEY;720		else721			type = BTRFS_TREE_BLOCK_REF_KEY;722	} else {723		if (parent > 0)724			type = BTRFS_SHARED_DATA_REF_KEY;725		else726			type = BTRFS_EXTENT_DATA_REF_KEY;727	}728	return type;729}730 731static int find_next_key(struct btrfs_path *path, int level,732			 struct btrfs_key *key)733 734{735	for (; level < BTRFS_MAX_LEVEL; level++) {736		if (!path->nodes[level])737			break;738		if (path->slots[level] + 1 >=739		    btrfs_header_nritems(path->nodes[level]))740			continue;741		if (level == 0)742			btrfs_item_key_to_cpu(path->nodes[level], key,743					      path->slots[level] + 1);744		else745			btrfs_node_key_to_cpu(path->nodes[level], key,746					      path->slots[level] + 1);747		return 0;748	}749	return 1;750}751 752/*753 * look for inline back ref. if back ref is found, *ref_ret is set754 * to the address of inline back ref, and 0 is returned.755 *756 * if back ref isn't found, *ref_ret is set to the address where it757 * should be inserted, and -ENOENT is returned.758 *759 * if insert is true and there are too many inline back refs, the path760 * points to the extent item, and -EAGAIN is returned.761 *762 * NOTE: inline back refs are ordered in the same way that back ref763 *	 items in the tree are ordered.764 */765static noinline_for_stack766int lookup_inline_extent_backref(struct btrfs_trans_handle *trans,767				 struct btrfs_path *path,768				 struct btrfs_extent_inline_ref **ref_ret,769				 u64 bytenr, u64 num_bytes,770				 u64 parent, u64 root_objectid,771				 u64 owner, u64 offset, int insert)772{773	struct btrfs_fs_info *fs_info = trans->fs_info;774	struct btrfs_root *root = btrfs_extent_root(fs_info, bytenr);775	struct btrfs_key key;776	struct extent_buffer *leaf;777	struct btrfs_extent_item *ei;778	struct btrfs_extent_inline_ref *iref;779	u64 flags;780	u64 item_size;781	unsigned long ptr;782	unsigned long end;783	int extra_size;784	int type;785	int want;786	int ret;787	bool skinny_metadata = btrfs_fs_incompat(fs_info, SKINNY_METADATA);788	int needed;789 790	key.objectid = bytenr;791	key.type = BTRFS_EXTENT_ITEM_KEY;792	key.offset = num_bytes;793 794	want = extent_ref_type(parent, owner);795	if (insert) {796		extra_size = btrfs_extent_inline_ref_size(want);797		path->search_for_extension = 1;798		path->keep_locks = 1;799	} else800		extra_size = -1;801 802	/*803	 * Owner is our level, so we can just add one to get the level for the804	 * block we are interested in.805	 */806	if (skinny_metadata && owner < BTRFS_FIRST_FREE_OBJECTID) {807		key.type = BTRFS_METADATA_ITEM_KEY;808		key.offset = owner;809	}810 811again:812	ret = btrfs_search_slot(trans, root, &key, path, extra_size, 1);813	if (ret < 0)814		goto out;815 816	/*817	 * We may be a newly converted file system which still has the old fat818	 * extent entries for metadata, so try and see if we have one of those.819	 */820	if (ret > 0 && skinny_metadata) {821		skinny_metadata = false;822		if (path->slots[0]) {823			path->slots[0]--;824			btrfs_item_key_to_cpu(path->nodes[0], &key,825					      path->slots[0]);826			if (key.objectid == bytenr &&827			    key.type == BTRFS_EXTENT_ITEM_KEY &&828			    key.offset == num_bytes)829				ret = 0;830		}831		if (ret) {832			key.objectid = bytenr;833			key.type = BTRFS_EXTENT_ITEM_KEY;834			key.offset = num_bytes;835			btrfs_release_path(path);836			goto again;837		}838	}839 840	if (ret && !insert) {841		ret = -ENOENT;842		goto out;843	} else if (WARN_ON(ret)) {844		btrfs_print_leaf(path->nodes[0]);845		btrfs_err(fs_info,846"extent item not found for insert, bytenr %llu num_bytes %llu parent %llu root_objectid %llu owner %llu offset %llu",847			  bytenr, num_bytes, parent, root_objectid, owner,848			  offset);849		ret = -EUCLEAN;850		goto out;851	}852 853	leaf = path->nodes[0];854	item_size = btrfs_item_size(leaf, path->slots[0]);855	if (unlikely(item_size < sizeof(*ei))) {856		ret = -EUCLEAN;857		btrfs_err(fs_info,858			  "unexpected extent item size, has %llu expect >= %zu",859			  item_size, sizeof(*ei));860		btrfs_abort_transaction(trans, ret);861		goto out;862	}863 864	ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);865	flags = btrfs_extent_flags(leaf, ei);866 867	ptr = (unsigned long)(ei + 1);868	end = (unsigned long)ei + item_size;869 870	if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK && !skinny_metadata) {871		ptr += sizeof(struct btrfs_tree_block_info);872		BUG_ON(ptr > end);873	}874 875	if (owner >= BTRFS_FIRST_FREE_OBJECTID)876		needed = BTRFS_REF_TYPE_DATA;877	else878		needed = BTRFS_REF_TYPE_BLOCK;879 880	ret = -ENOENT;881	while (ptr < end) {882		iref = (struct btrfs_extent_inline_ref *)ptr;883		type = btrfs_get_extent_inline_ref_type(leaf, iref, needed);884		if (type == BTRFS_EXTENT_OWNER_REF_KEY) {885			ASSERT(btrfs_fs_incompat(fs_info, SIMPLE_QUOTA));886			ptr += btrfs_extent_inline_ref_size(type);887			continue;888		}889		if (type == BTRFS_REF_TYPE_INVALID) {890			ret = -EUCLEAN;891			goto out;892		}893 894		if (want < type)895			break;896		if (want > type) {897			ptr += btrfs_extent_inline_ref_size(type);898			continue;899		}900 901		if (type == BTRFS_EXTENT_DATA_REF_KEY) {902			struct btrfs_extent_data_ref *dref;903			dref = (struct btrfs_extent_data_ref *)(&iref->offset);904			if (match_extent_data_ref(leaf, dref, root_objectid,905						  owner, offset)) {906				ret = 0;907				break;908			}909			if (hash_extent_data_ref_item(leaf, dref) <910			    hash_extent_data_ref(root_objectid, owner, offset))911				break;912		} else {913			u64 ref_offset;914			ref_offset = btrfs_extent_inline_ref_offset(leaf, iref);915			if (parent > 0) {916				if (parent == ref_offset) {917					ret = 0;918					break;919				}920				if (ref_offset < parent)921					break;922			} else {923				if (root_objectid == ref_offset) {924					ret = 0;925					break;926				}927				if (ref_offset < root_objectid)928					break;929			}930		}931		ptr += btrfs_extent_inline_ref_size(type);932	}933 934	if (unlikely(ptr > end)) {935		ret = -EUCLEAN;936		btrfs_print_leaf(path->nodes[0]);937		btrfs_crit(fs_info,938"overrun extent record at slot %d while looking for inline extent for root %llu owner %llu offset %llu parent %llu",939			   path->slots[0], root_objectid, owner, offset, parent);940		goto out;941	}942 943	if (ret == -ENOENT && insert) {944		if (item_size + extra_size >=945		    BTRFS_MAX_EXTENT_ITEM_SIZE(root)) {946			ret = -EAGAIN;947			goto out;948		}949		/*950		 * To add new inline back ref, we have to make sure951		 * there is no corresponding back ref item.952		 * For simplicity, we just do not add new inline back953		 * ref if there is any kind of item for this block954		 */955		if (find_next_key(path, 0, &key) == 0 &&956		    key.objectid == bytenr &&957		    key.type < BTRFS_BLOCK_GROUP_ITEM_KEY) {958			ret = -EAGAIN;959			goto out;960		}961	}962	*ref_ret = (struct btrfs_extent_inline_ref *)ptr;963out:964	if (insert) {965		path->keep_locks = 0;966		path->search_for_extension = 0;967		btrfs_unlock_up_safe(path, 1);968	}969	return ret;970}971 972/*973 * helper to add new inline back ref974 */975static noinline_for_stack976void setup_inline_extent_backref(struct btrfs_trans_handle *trans,977				 struct btrfs_path *path,978				 struct btrfs_extent_inline_ref *iref,979				 u64 parent, u64 root_objectid,980				 u64 owner, u64 offset, int refs_to_add,981				 struct btrfs_delayed_extent_op *extent_op)982{983	struct extent_buffer *leaf;984	struct btrfs_extent_item *ei;985	unsigned long ptr;986	unsigned long end;987	unsigned long item_offset;988	u64 refs;989	int size;990	int type;991 992	leaf = path->nodes[0];993	ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);994	item_offset = (unsigned long)iref - (unsigned long)ei;995 996	type = extent_ref_type(parent, owner);997	size = btrfs_extent_inline_ref_size(type);998 999	btrfs_extend_item(trans, path, size);1000 1001	ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);1002	refs = btrfs_extent_refs(leaf, ei);1003	refs += refs_to_add;1004	btrfs_set_extent_refs(leaf, ei, refs);1005	if (extent_op)1006		__run_delayed_extent_op(extent_op, leaf, ei);1007 1008	ptr = (unsigned long)ei + item_offset;1009	end = (unsigned long)ei + btrfs_item_size(leaf, path->slots[0]);1010	if (ptr < end - size)1011		memmove_extent_buffer(leaf, ptr + size, ptr,1012				      end - size - ptr);1013 1014	iref = (struct btrfs_extent_inline_ref *)ptr;1015	btrfs_set_extent_inline_ref_type(leaf, iref, type);1016	if (type == BTRFS_EXTENT_DATA_REF_KEY) {1017		struct btrfs_extent_data_ref *dref;1018		dref = (struct btrfs_extent_data_ref *)(&iref->offset);1019		btrfs_set_extent_data_ref_root(leaf, dref, root_objectid);1020		btrfs_set_extent_data_ref_objectid(leaf, dref, owner);1021		btrfs_set_extent_data_ref_offset(leaf, dref, offset);1022		btrfs_set_extent_data_ref_count(leaf, dref, refs_to_add);1023	} else if (type == BTRFS_SHARED_DATA_REF_KEY) {1024		struct btrfs_shared_data_ref *sref;1025		sref = (struct btrfs_shared_data_ref *)(iref + 1);1026		btrfs_set_shared_data_ref_count(leaf, sref, refs_to_add);1027		btrfs_set_extent_inline_ref_offset(leaf, iref, parent);1028	} else if (type == BTRFS_SHARED_BLOCK_REF_KEY) {1029		btrfs_set_extent_inline_ref_offset(leaf, iref, parent);1030	} else {1031		btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);1032	}1033	btrfs_mark_buffer_dirty(trans, leaf);1034}1035 1036static int lookup_extent_backref(struct btrfs_trans_handle *trans,1037				 struct btrfs_path *path,1038				 struct btrfs_extent_inline_ref **ref_ret,1039				 u64 bytenr, u64 num_bytes, u64 parent,1040				 u64 root_objectid, u64 owner, u64 offset)1041{1042	int ret;1043 1044	ret = lookup_inline_extent_backref(trans, path, ref_ret, bytenr,1045					   num_bytes, parent, root_objectid,1046					   owner, offset, 0);1047	if (ret != -ENOENT)1048		return ret;1049 1050	btrfs_release_path(path);1051	*ref_ret = NULL;1052 1053	if (owner < BTRFS_FIRST_FREE_OBJECTID) {1054		ret = lookup_tree_block_ref(trans, path, bytenr, parent,1055					    root_objectid);1056	} else {1057		ret = lookup_extent_data_ref(trans, path, bytenr, parent,1058					     root_objectid, owner, offset);1059	}1060	return ret;1061}1062 1063/*1064 * helper to update/remove inline back ref1065 */1066static noinline_for_stack int update_inline_extent_backref(1067				  struct btrfs_trans_handle *trans,1068				  struct btrfs_path *path,1069				  struct btrfs_extent_inline_ref *iref,1070				  int refs_to_mod,1071				  struct btrfs_delayed_extent_op *extent_op)1072{1073	struct extent_buffer *leaf = path->nodes[0];1074	struct btrfs_fs_info *fs_info = leaf->fs_info;1075	struct btrfs_extent_item *ei;1076	struct btrfs_extent_data_ref *dref = NULL;1077	struct btrfs_shared_data_ref *sref = NULL;1078	unsigned long ptr;1079	unsigned long end;1080	u32 item_size;1081	int size;1082	int type;1083	u64 refs;1084 1085	ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);1086	refs = btrfs_extent_refs(leaf, ei);1087	if (unlikely(refs_to_mod < 0 && refs + refs_to_mod <= 0)) {1088		struct btrfs_key key;1089		u32 extent_size;1090 1091		btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);1092		if (key.type == BTRFS_METADATA_ITEM_KEY)1093			extent_size = fs_info->nodesize;1094		else1095			extent_size = key.offset;1096		btrfs_print_leaf(leaf);1097		btrfs_err(fs_info,1098	"invalid refs_to_mod for extent %llu num_bytes %u, has %d expect >= -%llu",1099			  key.objectid, extent_size, refs_to_mod, refs);1100		return -EUCLEAN;1101	}1102	refs += refs_to_mod;1103	btrfs_set_extent_refs(leaf, ei, refs);1104	if (extent_op)1105		__run_delayed_extent_op(extent_op, leaf, ei);1106 1107	type = btrfs_get_extent_inline_ref_type(leaf, iref, BTRFS_REF_TYPE_ANY);1108	/*1109	 * Function btrfs_get_extent_inline_ref_type() has already printed1110	 * error messages.1111	 */1112	if (unlikely(type == BTRFS_REF_TYPE_INVALID))1113		return -EUCLEAN;1114 1115	if (type == BTRFS_EXTENT_DATA_REF_KEY) {1116		dref = (struct btrfs_extent_data_ref *)(&iref->offset);1117		refs = btrfs_extent_data_ref_count(leaf, dref);1118	} else if (type == BTRFS_SHARED_DATA_REF_KEY) {1119		sref = (struct btrfs_shared_data_ref *)(iref + 1);1120		refs = btrfs_shared_data_ref_count(leaf, sref);1121	} else {1122		refs = 1;1123		/*1124		 * For tree blocks we can only drop one ref for it, and tree1125		 * blocks should not have refs > 1.1126		 *1127		 * Furthermore if we're inserting a new inline backref, we1128		 * won't reach this path either. That would be1129		 * setup_inline_extent_backref().1130		 */1131		if (unlikely(refs_to_mod != -1)) {1132			struct btrfs_key key;1133 1134			btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);1135 1136			btrfs_print_leaf(leaf);1137			btrfs_err(fs_info,1138			"invalid refs_to_mod for tree block %llu, has %d expect -1",1139				  key.objectid, refs_to_mod);1140			return -EUCLEAN;1141		}1142	}1143 1144	if (unlikely(refs_to_mod < 0 && refs < -refs_to_mod)) {1145		struct btrfs_key key;1146		u32 extent_size;1147 1148		btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);1149		if (key.type == BTRFS_METADATA_ITEM_KEY)1150			extent_size = fs_info->nodesize;1151		else1152			extent_size = key.offset;1153		btrfs_print_leaf(leaf);1154		btrfs_err(fs_info,1155"invalid refs_to_mod for backref entry, iref %lu extent %llu num_bytes %u, has %d expect >= -%llu",1156			  (unsigned long)iref, key.objectid, extent_size,1157			  refs_to_mod, refs);1158		return -EUCLEAN;1159	}1160	refs += refs_to_mod;1161 1162	if (refs > 0) {1163		if (type == BTRFS_EXTENT_DATA_REF_KEY)1164			btrfs_set_extent_data_ref_count(leaf, dref, refs);1165		else1166			btrfs_set_shared_data_ref_count(leaf, sref, refs);1167	} else {1168		size =  btrfs_extent_inline_ref_size(type);1169		item_size = btrfs_item_size(leaf, path->slots[0]);1170		ptr = (unsigned long)iref;1171		end = (unsigned long)ei + item_size;1172		if (ptr + size < end)1173			memmove_extent_buffer(leaf, ptr, ptr + size,1174					      end - ptr - size);1175		item_size -= size;1176		btrfs_truncate_item(trans, path, item_size, 1);1177	}1178	btrfs_mark_buffer_dirty(trans, leaf);1179	return 0;1180}1181 1182static noinline_for_stack1183int insert_inline_extent_backref(struct btrfs_trans_handle *trans,1184				 struct btrfs_path *path,1185				 u64 bytenr, u64 num_bytes, u64 parent,1186				 u64 root_objectid, u64 owner,1187				 u64 offset, int refs_to_add,1188				 struct btrfs_delayed_extent_op *extent_op)1189{1190	struct btrfs_extent_inline_ref *iref;1191	int ret;1192 1193	ret = lookup_inline_extent_backref(trans, path, &iref, bytenr,1194					   num_bytes, parent, root_objectid,1195					   owner, offset, 1);1196	if (ret == 0) {1197		/*1198		 * We're adding refs to a tree block we already own, this1199		 * should not happen at all.1200		 */1201		if (owner < BTRFS_FIRST_FREE_OBJECTID) {1202			btrfs_print_leaf(path->nodes[0]);1203			btrfs_crit(trans->fs_info,1204"adding refs to an existing tree ref, bytenr %llu num_bytes %llu root_objectid %llu slot %u",1205				   bytenr, num_bytes, root_objectid, path->slots[0]);1206			return -EUCLEAN;1207		}1208		ret = update_inline_extent_backref(trans, path, iref,1209						   refs_to_add, extent_op);1210	} else if (ret == -ENOENT) {1211		setup_inline_extent_backref(trans, path, iref, parent,1212					    root_objectid, owner, offset,1213					    refs_to_add, extent_op);1214		ret = 0;1215	}1216	return ret;1217}1218 1219static int remove_extent_backref(struct btrfs_trans_handle *trans,1220				 struct btrfs_root *root,1221				 struct btrfs_path *path,1222				 struct btrfs_extent_inline_ref *iref,1223				 int refs_to_drop, int is_data)1224{1225	int ret = 0;1226 1227	BUG_ON(!is_data && refs_to_drop != 1);1228	if (iref)1229		ret = update_inline_extent_backref(trans, path, iref,1230						   -refs_to_drop, NULL);1231	else if (is_data)1232		ret = remove_extent_data_ref(trans, root, path, refs_to_drop);1233	else1234		ret = btrfs_del_item(trans, root, path);1235	return ret;1236}1237 1238static int btrfs_issue_discard(struct block_device *bdev, u64 start, u64 len,1239			       u64 *discarded_bytes)1240{1241	int j, ret = 0;1242	u64 bytes_left, end;1243	u64 aligned_start = ALIGN(start, 1 << SECTOR_SHIFT);1244 1245	/* Adjust the range to be aligned to 512B sectors if necessary. */1246	if (start != aligned_start) {1247		len -= aligned_start - start;1248		len = round_down(len, 1 << SECTOR_SHIFT);1249		start = aligned_start;1250	}1251 1252	*discarded_bytes = 0;1253 1254	if (!len)1255		return 0;1256 1257	end = start + len;1258	bytes_left = len;1259 1260	/* Skip any superblocks on this device. */1261	for (j = 0; j < BTRFS_SUPER_MIRROR_MAX; j++) {1262		u64 sb_start = btrfs_sb_offset(j);1263		u64 sb_end = sb_start + BTRFS_SUPER_INFO_SIZE;1264		u64 size = sb_start - start;1265 1266		if (!in_range(sb_start, start, bytes_left) &&1267		    !in_range(sb_end, start, bytes_left) &&1268		    !in_range(start, sb_start, BTRFS_SUPER_INFO_SIZE))1269			continue;1270 1271		/*1272		 * Superblock spans beginning of range.  Adjust start and1273		 * try again.1274		 */1275		if (sb_start <= start) {1276			start += sb_end - start;1277			if (start > end) {1278				bytes_left = 0;1279				break;1280			}1281			bytes_left = end - start;1282			continue;1283		}1284 1285		if (size) {1286			ret = blkdev_issue_discard(bdev, start >> SECTOR_SHIFT,1287						   size >> SECTOR_SHIFT,1288						   GFP_NOFS);1289			if (!ret)1290				*discarded_bytes += size;1291			else if (ret != -EOPNOTSUPP)1292				return ret;1293		}1294 1295		start = sb_end;1296		if (start > end) {1297			bytes_left = 0;1298			break;1299		}1300		bytes_left = end - start;1301	}1302 1303	while (bytes_left) {1304		u64 bytes_to_discard = min(BTRFS_MAX_DISCARD_CHUNK_SIZE, bytes_left);1305 1306		ret = blkdev_issue_discard(bdev, start >> SECTOR_SHIFT,1307					   bytes_to_discard >> SECTOR_SHIFT,1308					   GFP_NOFS);1309 1310		if (ret) {1311			if (ret != -EOPNOTSUPP)1312				break;1313			continue;1314		}1315 1316		start += bytes_to_discard;1317		bytes_left -= bytes_to_discard;1318		*discarded_bytes += bytes_to_discard;1319 1320		if (btrfs_trim_interrupted()) {1321			ret = -ERESTARTSYS;1322			break;1323		}1324	}1325 1326	return ret;1327}1328 1329static int do_discard_extent(struct btrfs_discard_stripe *stripe, u64 *bytes)1330{1331	struct btrfs_device *dev = stripe->dev;1332	struct btrfs_fs_info *fs_info = dev->fs_info;1333	struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;1334	u64 phys = stripe->physical;1335	u64 len = stripe->length;1336	u64 discarded = 0;1337	int ret = 0;1338 1339	/* Zone reset on a zoned filesystem */1340	if (btrfs_can_zone_reset(dev, phys, len)) {1341		u64 src_disc;1342 1343		ret = btrfs_reset_device_zone(dev, phys, len, &discarded);1344		if (ret)1345			goto out;1346 1347		if (!btrfs_dev_replace_is_ongoing(dev_replace) ||1348		    dev != dev_replace->srcdev)1349			goto out;1350 1351		src_disc = discarded;1352 1353		/* Send to replace target as well */1354		ret = btrfs_reset_device_zone(dev_replace->tgtdev, phys, len,1355					      &discarded);1356		discarded += src_disc;1357	} else if (bdev_max_discard_sectors(stripe->dev->bdev)) {1358		ret = btrfs_issue_discard(dev->bdev, phys, len, &discarded);1359	} else {1360		ret = 0;1361		*bytes = 0;1362	}1363 1364out:1365	*bytes = discarded;1366	return ret;1367}1368 1369int btrfs_discard_extent(struct btrfs_fs_info *fs_info, u64 bytenr,1370			 u64 num_bytes, u64 *actual_bytes)1371{1372	int ret = 0;1373	u64 discarded_bytes = 0;1374	u64 end = bytenr + num_bytes;1375	u64 cur = bytenr;1376 1377	/*1378	 * Avoid races with device replace and make sure the devices in the1379	 * stripes don't go away while we are discarding.1380	 */1381	btrfs_bio_counter_inc_blocked(fs_info);1382	while (cur < end) {1383		struct btrfs_discard_stripe *stripes;1384		unsigned int num_stripes;1385		int i;1386 1387		num_bytes = end - cur;1388		stripes = btrfs_map_discard(fs_info, cur, &num_bytes, &num_stripes);1389		if (IS_ERR(stripes)) {1390			ret = PTR_ERR(stripes);1391			if (ret == -EOPNOTSUPP)1392				ret = 0;1393			break;1394		}1395 1396		for (i = 0; i < num_stripes; i++) {1397			struct btrfs_discard_stripe *stripe = stripes + i;1398			u64 bytes;1399 1400			if (!stripe->dev->bdev) {1401				ASSERT(btrfs_test_opt(fs_info, DEGRADED));1402				continue;1403			}1404 1405			if (!test_bit(BTRFS_DEV_STATE_WRITEABLE,1406					&stripe->dev->dev_state))1407				continue;1408 1409			ret = do_discard_extent(stripe, &bytes);1410			if (ret) {1411				/*1412				 * Keep going if discard is not supported by the1413				 * device.1414				 */1415				if (ret != -EOPNOTSUPP)1416					break;1417				ret = 0;1418			} else {1419				discarded_bytes += bytes;1420			}1421		}1422		kfree(stripes);1423		if (ret)1424			break;1425		cur += num_bytes;1426	}1427	btrfs_bio_counter_dec(fs_info);1428	if (actual_bytes)1429		*actual_bytes = discarded_bytes;1430	return ret;1431}1432 1433/* Can return -ENOMEM */1434int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,1435			 struct btrfs_ref *generic_ref)1436{1437	struct btrfs_fs_info *fs_info = trans->fs_info;1438	int ret;1439 1440	ASSERT(generic_ref->type != BTRFS_REF_NOT_SET &&1441	       generic_ref->action);1442	BUG_ON(generic_ref->type == BTRFS_REF_METADATA &&1443	       generic_ref->ref_root == BTRFS_TREE_LOG_OBJECTID);1444 1445	if (generic_ref->type == BTRFS_REF_METADATA)1446		ret = btrfs_add_delayed_tree_ref(trans, generic_ref, NULL);1447	else1448		ret = btrfs_add_delayed_data_ref(trans, generic_ref, 0);1449 1450	btrfs_ref_tree_mod(fs_info, generic_ref);1451 1452	return ret;1453}1454 1455/*1456 * Insert backreference for a given extent.1457 *1458 * The counterpart is in __btrfs_free_extent(), with examples and more details1459 * how it works.1460 *1461 * @trans:	    Handle of transaction1462 *1463 * @node:	    The delayed ref node used to get the bytenr/length for1464 *		    extent whose references are incremented.1465 *1466 * @extent_op       Pointer to a structure, holding information necessary when1467 *                  updating a tree block's flags1468 *1469 */1470static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,1471				  struct btrfs_delayed_ref_node *node,1472				  struct btrfs_delayed_extent_op *extent_op)1473{1474	struct btrfs_path *path;1475	struct extent_buffer *leaf;1476	struct btrfs_extent_item *item;1477	struct btrfs_key key;1478	u64 bytenr = node->bytenr;1479	u64 num_bytes = node->num_bytes;1480	u64 owner = btrfs_delayed_ref_owner(node);1481	u64 offset = btrfs_delayed_ref_offset(node);1482	u64 refs;1483	int refs_to_add = node->ref_mod;1484	int ret;1485 1486	path = btrfs_alloc_path();1487	if (!path)1488		return -ENOMEM;1489 1490	/* this will setup the path even if it fails to insert the back ref */1491	ret = insert_inline_extent_backref(trans, path, bytenr, num_bytes,1492					   node->parent, node->ref_root, owner,1493					   offset, refs_to_add, extent_op);1494	if ((ret < 0 && ret != -EAGAIN) || !ret)1495		goto out;1496 1497	/*1498	 * Ok we had -EAGAIN which means we didn't have space to insert and1499	 * inline extent ref, so just update the reference count and add a1500	 * normal backref.1501	 */1502	leaf = path->nodes[0];1503	btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);1504	item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);1505	refs = btrfs_extent_refs(leaf, item);1506	btrfs_set_extent_refs(leaf, item, refs + refs_to_add);1507	if (extent_op)1508		__run_delayed_extent_op(extent_op, leaf, item);1509 1510	btrfs_mark_buffer_dirty(trans, leaf);1511	btrfs_release_path(path);1512 1513	/* now insert the actual backref */1514	if (owner < BTRFS_FIRST_FREE_OBJECTID)1515		ret = insert_tree_block_ref(trans, path, node, bytenr);1516	else1517		ret = insert_extent_data_ref(trans, path, node, bytenr);1518 1519	if (ret)1520		btrfs_abort_transaction(trans, ret);1521out:1522	btrfs_free_path(path);1523	return ret;1524}1525 1526static void free_head_ref_squota_rsv(struct btrfs_fs_info *fs_info,1527				     struct btrfs_delayed_ref_head *href)1528{1529	u64 root = href->owning_root;1530 1531	/*1532	 * Don't check must_insert_reserved, as this is called from contexts1533	 * where it has already been unset.1534	 */1535	if (btrfs_qgroup_mode(fs_info) != BTRFS_QGROUP_MODE_SIMPLE ||1536	    !href->is_data || !is_fstree(root))1537		return;1538 1539	btrfs_qgroup_free_refroot(fs_info, root, href->reserved_bytes,1540				  BTRFS_QGROUP_RSV_DATA);1541}1542 1543static int run_delayed_data_ref(struct btrfs_trans_handle *trans,1544				struct btrfs_delayed_ref_head *href,1545				struct btrfs_delayed_ref_node *node,1546				struct btrfs_delayed_extent_op *extent_op,1547				bool insert_reserved)1548{1549	int ret = 0;1550	u64 parent = 0;1551	u64 flags = 0;1552 1553	trace_run_delayed_data_ref(trans->fs_info, node);1554 1555	if (node->type == BTRFS_SHARED_DATA_REF_KEY)1556		parent = node->parent;1557 1558	if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {1559		struct btrfs_key key;1560		struct btrfs_squota_delta delta = {1561			.root = href->owning_root,1562			.num_bytes = node->num_bytes,1563			.is_data = true,1564			.is_inc	= true,1565			.generation = trans->transid,1566		};1567		u64 owner = btrfs_delayed_ref_owner(node);1568		u64 offset = btrfs_delayed_ref_offset(node);1569 1570		if (extent_op)1571			flags |= extent_op->flags_to_set;1572 1573		key.objectid = node->bytenr;1574		key.type = BTRFS_EXTENT_ITEM_KEY;1575		key.offset = node->num_bytes;1576 1577		ret = alloc_reserved_file_extent(trans, parent, node->ref_root,1578						 flags, owner, offset, &key,1579						 node->ref_mod,1580						 href->owning_root);1581		free_head_ref_squota_rsv(trans->fs_info, href);1582		if (!ret)1583			ret = btrfs_record_squota_delta(trans->fs_info, &delta);1584	} else if (node->action == BTRFS_ADD_DELAYED_REF) {1585		ret = __btrfs_inc_extent_ref(trans, node, extent_op);1586	} else if (node->action == BTRFS_DROP_DELAYED_REF) {1587		ret = __btrfs_free_extent(trans, href, node, extent_op);1588	} else {1589		BUG();1590	}1591	return ret;1592}1593 1594static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,1595				    struct extent_buffer *leaf,1596				    struct btrfs_extent_item *ei)1597{1598	u64 flags = btrfs_extent_flags(leaf, ei);1599	if (extent_op->update_flags) {1600		flags |= extent_op->flags_to_set;1601		btrfs_set_extent_flags(leaf, ei, flags);1602	}1603 1604	if (extent_op->update_key) {1605		struct btrfs_tree_block_info *bi;1606		BUG_ON(!(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK));1607		bi = (struct btrfs_tree_block_info *)(ei + 1);1608		btrfs_set_tree_block_key(leaf, bi, &extent_op->key);1609	}1610}1611 1612static int run_delayed_extent_op(struct btrfs_trans_handle *trans,1613				 struct btrfs_delayed_ref_head *head,1614				 struct btrfs_delayed_extent_op *extent_op)1615{1616	struct btrfs_fs_info *fs_info = trans->fs_info;1617	struct btrfs_root *root;1618	struct btrfs_key key;1619	struct btrfs_path *path;1620	struct btrfs_extent_item *ei;1621	struct extent_buffer *leaf;1622	u32 item_size;1623	int ret;1624	int metadata = 1;1625 1626	if (TRANS_ABORTED(trans))1627		return 0;1628 1629	if (!btrfs_fs_incompat(fs_info, SKINNY_METADATA))1630		metadata = 0;1631 1632	path = btrfs_alloc_path();1633	if (!path)1634		return -ENOMEM;1635 1636	key.objectid = head->bytenr;1637 1638	if (metadata) {1639		key.type = BTRFS_METADATA_ITEM_KEY;1640		key.offset = head->level;1641	} else {1642		key.type = BTRFS_EXTENT_ITEM_KEY;1643		key.offset = head->num_bytes;1644	}1645 1646	root = btrfs_extent_root(fs_info, key.objectid);1647again:1648	ret = btrfs_search_slot(trans, root, &key, path, 0, 1);1649	if (ret < 0) {1650		goto out;1651	} else if (ret > 0) {1652		if (metadata) {1653			if (path->slots[0] > 0) {1654				path->slots[0]--;1655				btrfs_item_key_to_cpu(path->nodes[0], &key,1656						      path->slots[0]);1657				if (key.objectid == head->bytenr &&1658				    key.type == BTRFS_EXTENT_ITEM_KEY &&1659				    key.offset == head->num_bytes)1660					ret = 0;1661			}1662			if (ret > 0) {1663				btrfs_release_path(path);1664				metadata = 0;1665 1666				key.objectid = head->bytenr;1667				key.offset = head->num_bytes;1668				key.type = BTRFS_EXTENT_ITEM_KEY;1669				goto again;1670			}1671		} else {1672			ret = -EUCLEAN;1673			btrfs_err(fs_info,1674		  "missing extent item for extent %llu num_bytes %llu level %d",1675				  head->bytenr, head->num_bytes, head->level);1676			goto out;1677		}1678	}1679 1680	leaf = path->nodes[0];1681	item_size = btrfs_item_size(leaf, path->slots[0]);1682 1683	if (unlikely(item_size < sizeof(*ei))) {1684		ret = -EUCLEAN;1685		btrfs_err(fs_info,1686			  "unexpected extent item size, has %u expect >= %zu",1687			  item_size, sizeof(*ei));1688		btrfs_abort_transaction(trans, ret);1689		goto out;1690	}1691 1692	ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);1693	__run_delayed_extent_op(extent_op, leaf, ei);1694 1695	btrfs_mark_buffer_dirty(trans, leaf);1696out:1697	btrfs_free_path(path);1698	return ret;1699}1700 1701static int run_delayed_tree_ref(struct btrfs_trans_handle *trans,1702				struct btrfs_delayed_ref_head *href,1703				struct btrfs_delayed_ref_node *node,1704				struct btrfs_delayed_extent_op *extent_op,1705				bool insert_reserved)1706{1707	int ret = 0;1708	struct btrfs_fs_info *fs_info = trans->fs_info;1709	u64 parent = 0;1710	u64 ref_root = 0;1711 1712	trace_run_delayed_tree_ref(trans->fs_info, node);1713 1714	if (node->type == BTRFS_SHARED_BLOCK_REF_KEY)1715		parent = node->parent;1716	ref_root = node->ref_root;1717 1718	if (unlikely(node->ref_mod != 1)) {1719		btrfs_err(trans->fs_info,1720	"btree block %llu has %d references rather than 1: action %d ref_root %llu parent %llu",1721			  node->bytenr, node->ref_mod, node->action, ref_root,1722			  parent);1723		return -EUCLEAN;1724	}1725	if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {1726		struct btrfs_squota_delta delta = {1727			.root = href->owning_root,1728			.num_bytes = fs_info->nodesize,1729			.is_data = false,1730			.is_inc = true,1731			.generation = trans->transid,1732		};1733 1734		ret = alloc_reserved_tree_block(trans, node, extent_op);1735		if (!ret)1736			btrfs_record_squota_delta(fs_info, &delta);1737	} else if (node->action == BTRFS_ADD_DELAYED_REF) {1738		ret = __btrfs_inc_extent_ref(trans, node, extent_op);1739	} else if (node->action == BTRFS_DROP_DELAYED_REF) {1740		ret = __btrfs_free_extent(trans, href, node, extent_op);1741	} else {1742		BUG();1743	}1744	return ret;1745}1746 1747/* helper function to actually process a single delayed ref entry */1748static int run_one_delayed_ref(struct btrfs_trans_handle *trans,1749			       struct btrfs_delayed_ref_head *href,1750			       struct btrfs_delayed_ref_node *node,1751			       struct btrfs_delayed_extent_op *extent_op,1752			       bool insert_reserved)1753{1754	int ret = 0;1755 1756	if (TRANS_ABORTED(trans)) {1757		if (insert_reserved) {1758			btrfs_pin_extent(trans, node->bytenr, node->num_bytes, 1);1759			free_head_ref_squota_rsv(trans->fs_info, href);1760		}1761		return 0;1762	}1763 1764	if (node->type == BTRFS_TREE_BLOCK_REF_KEY ||1765	    node->type == BTRFS_SHARED_BLOCK_REF_KEY)1766		ret = run_delayed_tree_ref(trans, href, node, extent_op,1767					   insert_reserved);1768	else if (node->type == BTRFS_EXTENT_DATA_REF_KEY ||1769		 node->type == BTRFS_SHARED_DATA_REF_KEY)1770		ret = run_delayed_data_ref(trans, href, node, extent_op,1771					   insert_reserved);1772	else if (node->type == BTRFS_EXTENT_OWNER_REF_KEY)1773		ret = 0;1774	else1775		BUG();1776	if (ret && insert_reserved)1777		btrfs_pin_extent(trans, node->bytenr, node->num_bytes, 1);1778	if (ret < 0)1779		btrfs_err(trans->fs_info,1780"failed to run delayed ref for logical %llu num_bytes %llu type %u action %u ref_mod %d: %d",1781			  node->bytenr, node->num_bytes, node->type,1782			  node->action, node->ref_mod, ret);1783	return ret;1784}1785 1786static inline struct btrfs_delayed_ref_node *1787select_delayed_ref(struct btrfs_delayed_ref_head *head)1788{1789	struct btrfs_delayed_ref_node *ref;1790 1791	if (RB_EMPTY_ROOT(&head->ref_tree.rb_root))1792		return NULL;1793 1794	/*1795	 * Select a delayed ref of type BTRFS_ADD_DELAYED_REF first.1796	 * This is to prevent a ref count from going down to zero, which deletes1797	 * the extent item from the extent tree, when there still are references1798	 * to add, which would fail because they would not find the extent item.1799	 */1800	if (!list_empty(&head->ref_add_list))1801		return list_first_entry(&head->ref_add_list,1802				struct btrfs_delayed_ref_node, add_list);1803 1804	ref = rb_entry(rb_first_cached(&head->ref_tree),1805		       struct btrfs_delayed_ref_node, ref_node);1806	ASSERT(list_empty(&ref->add_list));1807	return ref;1808}1809 1810static void unselect_delayed_ref_head(struct btrfs_delayed_ref_root *delayed_refs,1811				      struct btrfs_delayed_ref_head *head)1812{1813	spin_lock(&delayed_refs->lock);1814	head->processing = false;1815	delayed_refs->num_heads_ready++;1816	spin_unlock(&delayed_refs->lock);1817	btrfs_delayed_ref_unlock(head);1818}1819 1820static struct btrfs_delayed_extent_op *cleanup_extent_op(1821				struct btrfs_delayed_ref_head *head)1822{1823	struct btrfs_delayed_extent_op *extent_op = head->extent_op;1824 1825	if (!extent_op)1826		return NULL;1827 1828	if (head->must_insert_reserved) {1829		head->extent_op = NULL;1830		btrfs_free_delayed_extent_op(extent_op);1831		return NULL;1832	}1833	return extent_op;1834}1835 1836static int run_and_cleanup_extent_op(struct btrfs_trans_handle *trans,1837				     struct btrfs_delayed_ref_head *head)1838{1839	struct btrfs_delayed_extent_op *extent_op;1840	int ret;1841 1842	extent_op = cleanup_extent_op(head);1843	if (!extent_op)1844		return 0;1845	head->extent_op = NULL;1846	spin_unlock(&head->lock);1847	ret = run_delayed_extent_op(trans, head, extent_op);1848	btrfs_free_delayed_extent_op(extent_op);1849	return ret ? ret : 1;1850}1851 1852u64 btrfs_cleanup_ref_head_accounting(struct btrfs_fs_info *fs_info,1853				  struct btrfs_delayed_ref_root *delayed_refs,1854				  struct btrfs_delayed_ref_head *head)1855{1856	u64 ret = 0;1857 1858	/*1859	 * We had csum deletions accounted for in our delayed refs rsv, we need1860	 * to drop the csum leaves for this update from our delayed_refs_rsv.1861	 */1862	if (head->total_ref_mod < 0 && head->is_data) {1863		int nr_csums;1864 1865		spin_lock(&delayed_refs->lock);1866		delayed_refs->pending_csums -= head->num_bytes;1867		spin_unlock(&delayed_refs->lock);1868		nr_csums = btrfs_csum_bytes_to_leaves(fs_info, head->num_bytes);1869 1870		btrfs_delayed_refs_rsv_release(fs_info, 0, nr_csums);1871 1872		ret = btrfs_calc_delayed_ref_csum_bytes(fs_info, nr_csums);1873	}1874	/* must_insert_reserved can be set only if we didn't run the head ref. */1875	if (head->must_insert_reserved)1876		free_head_ref_squota_rsv(fs_info, head);1877 1878	return ret;1879}1880 1881static int cleanup_ref_head(struct btrfs_trans_handle *trans,1882			    struct btrfs_delayed_ref_head *head,1883			    u64 *bytes_released)1884{1885 1886	struct btrfs_fs_info *fs_info = trans->fs_info;1887	struct btrfs_delayed_ref_root *delayed_refs;1888	int ret;1889 1890	delayed_refs = &trans->transaction->delayed_refs;1891 1892	ret = run_and_cleanup_extent_op(trans, head);1893	if (ret < 0) {1894		unselect_delayed_ref_head(delayed_refs, head);1895		btrfs_debug(fs_info, "run_delayed_extent_op returned %d", ret);1896		return ret;1897	} else if (ret) {1898		return ret;1899	}1900 1901	/*1902	 * Need to drop our head ref lock and re-acquire the delayed ref lock1903	 * and then re-check to make sure nobody got added.1904	 */1905	spin_unlock(&head->lock);1906	spin_lock(&delayed_refs->lock);1907	spin_lock(&head->lock);1908	if (!RB_EMPTY_ROOT(&head->ref_tree.rb_root) || head->extent_op) {1909		spin_unlock(&head->lock);1910		spin_unlock(&delayed_refs->lock);1911		return 1;1912	}1913	btrfs_delete_ref_head(delayed_refs, head);1914	spin_unlock(&head->lock);1915	spin_unlock(&delayed_refs->lock);1916 1917	if (head->must_insert_reserved) {1918		btrfs_pin_extent(trans, head->bytenr, head->num_bytes, 1);1919		if (head->is_data) {1920			struct btrfs_root *csum_root;1921 1922			csum_root = btrfs_csum_root(fs_info, head->bytenr);1923			ret = btrfs_del_csums(trans, csum_root, head->bytenr,1924					      head->num_bytes);1925		}1926	}1927 1928	*bytes_released += btrfs_cleanup_ref_head_accounting(fs_info, delayed_refs, head);1929 1930	trace_run_delayed_ref_head(fs_info, head, 0);1931	btrfs_delayed_ref_unlock(head);1932	btrfs_put_delayed_ref_head(head);1933	return ret;1934}1935 1936static struct btrfs_delayed_ref_head *btrfs_obtain_ref_head(1937					struct btrfs_trans_handle *trans)1938{1939	struct btrfs_delayed_ref_root *delayed_refs =1940		&trans->transaction->delayed_refs;1941	struct btrfs_delayed_ref_head *head = NULL;1942	int ret;1943 1944	spin_lock(&delayed_refs->lock);1945	head = btrfs_select_ref_head(delayed_refs);1946	if (!head) {1947		spin_unlock(&delayed_refs->lock);1948		return head;1949	}1950 1951	/*1952	 * Grab the lock that says we are going to process all the refs for1953	 * this head1954	 */1955	ret = btrfs_delayed_ref_lock(delayed_refs, head);1956	spin_unlock(&delayed_refs->lock);1957 1958	/*1959	 * We may have dropped the spin lock to get the head mutex lock, and1960	 * that might have given someone else time to free the head.  If that's1961	 * true, it has been removed from our list and we can move on.1962	 */1963	if (ret == -EAGAIN)1964		head = ERR_PTR(-EAGAIN);1965 1966	return head;1967}1968 1969static int btrfs_run_delayed_refs_for_head(struct btrfs_trans_handle *trans,1970					   struct btrfs_delayed_ref_head *locked_ref,1971					   u64 *bytes_released)1972{1973	struct btrfs_fs_info *fs_info = trans->fs_info;1974	struct btrfs_delayed_ref_root *delayed_refs;1975	struct btrfs_delayed_extent_op *extent_op;1976	struct btrfs_delayed_ref_node *ref;1977	bool must_insert_reserved;1978	int ret;1979 1980	delayed_refs = &trans->transaction->delayed_refs;1981 1982	lockdep_assert_held(&locked_ref->mutex);1983	lockdep_assert_held(&locked_ref->lock);1984 1985	while ((ref = select_delayed_ref(locked_ref))) {1986		if (ref->seq &&1987		    btrfs_check_delayed_seq(fs_info, ref->seq)) {1988			spin_unlock(&locked_ref->lock);1989			unselect_delayed_ref_head(delayed_refs, locked_ref);1990			return -EAGAIN;1991		}1992 1993		rb_erase_cached(&ref->ref_node, &locked_ref->ref_tree);1994		RB_CLEAR_NODE(&ref->ref_node);1995		if (!list_empty(&ref->add_list))1996			list_del(&ref->add_list);1997		/*1998		 * When we play the delayed ref, also correct the ref_mod on1999		 * head2000		 */2001		switch (ref->action) {2002		case BTRFS_ADD_DELAYED_REF:2003		case BTRFS_ADD_DELAYED_EXTENT:2004			locked_ref->ref_mod -= ref->ref_mod;2005			break;2006		case BTRFS_DROP_DELAYED_REF:2007			locked_ref->ref_mod += ref->ref_mod;2008			break;2009		default:2010			WARN_ON(1);2011		}2012		atomic_dec(&delayed_refs->num_entries);2013 2014		/*2015		 * Record the must_insert_reserved flag before we drop the2016		 * spin lock.2017		 */2018		must_insert_reserved = locked_ref->must_insert_reserved;2019		/*2020		 * Unsetting this on the head ref relinquishes ownership of2021		 * the rsv_bytes, so it is critical that every possible code2022		 * path from here forward frees all reserves including qgroup2023		 * reserve.2024		 */2025		locked_ref->must_insert_reserved = false;2026 2027		extent_op = locked_ref->extent_op;2028		locked_ref->extent_op = NULL;2029		spin_unlock(&locked_ref->lock);2030 2031		ret = run_one_delayed_ref(trans, locked_ref, ref, extent_op,2032					  must_insert_reserved);2033		btrfs_delayed_refs_rsv_release(fs_info, 1, 0);2034		*bytes_released += btrfs_calc_delayed_ref_bytes(fs_info, 1);2035 2036		btrfs_free_delayed_extent_op(extent_op);2037		if (ret) {2038			unselect_delayed_ref_head(delayed_refs, locked_ref);2039			btrfs_put_delayed_ref(ref);2040			return ret;2041		}2042 2043		btrfs_put_delayed_ref(ref);2044		cond_resched();2045 2046		spin_lock(&locked_ref->lock);2047		btrfs_merge_delayed_refs(fs_info, delayed_refs, locked_ref);2048	}2049 2050	return 0;2051}2052 2053/*2054 * Returns 0 on success or if called with an already aborted transaction.2055 * Returns -ENOMEM or -EIO on failure and will abort the transaction.2056 */2057static noinline int __btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,2058					     u64 min_bytes)2059{2060	struct btrfs_fs_info *fs_info = trans->fs_info;2061	struct btrfs_delayed_ref_root *delayed_refs;2062	struct btrfs_delayed_ref_head *locked_ref = NULL;2063	int ret;2064	unsigned long count = 0;2065	unsigned long max_count = 0;2066	u64 bytes_processed = 0;2067 2068	delayed_refs = &trans->transaction->delayed_refs;2069	if (min_bytes == 0) {2070		max_count = delayed_refs->num_heads_ready;2071		min_bytes = U64_MAX;2072	}2073 2074	do {2075		if (!locked_ref) {2076			locked_ref = btrfs_obtain_ref_head(trans);2077			if (IS_ERR_OR_NULL(locked_ref)) {2078				if (PTR_ERR(locked_ref) == -EAGAIN) {2079					continue;2080				} else {2081					break;2082				}2083			}2084			count++;2085		}2086		/*2087		 * We need to try and merge add/drops of the same ref since we2088		 * can run into issues with relocate dropping the implicit ref2089		 * and then it being added back again before the drop can2090		 * finish.  If we merged anything we need to re-loop so we can2091		 * get a good ref.2092		 * Or we can get node references of the same type that weren't2093		 * merged when created due to bumps in the tree mod seq, and2094		 * we need to merge them to prevent adding an inline extent2095		 * backref before dropping it (triggering a BUG_ON at2096		 * insert_inline_extent_backref()).2097		 */2098		spin_lock(&locked_ref->lock);2099		btrfs_merge_delayed_refs(fs_info, delayed_refs, locked_ref);2100 2101		ret = btrfs_run_delayed_refs_for_head(trans, locked_ref, &bytes_processed);2102		if (ret < 0 && ret != -EAGAIN) {2103			/*2104			 * Error, btrfs_run_delayed_refs_for_head already2105			 * unlocked everything so just bail out2106			 */2107			return ret;2108		} else if (!ret) {2109			/*2110			 * Success, perform the usual cleanup of a processed2111			 * head2112			 */2113			ret = cleanup_ref_head(trans, locked_ref, &bytes_processed);2114			if (ret > 0 ) {2115				/* We dropped our lock, we need to loop. */2116				ret = 0;2117				continue;2118			} else if (ret) {2119				return ret;2120			}2121		}2122 2123		/*2124		 * Either success case or btrfs_run_delayed_refs_for_head2125		 * returned -EAGAIN, meaning we need to select another head2126		 */2127 2128		locked_ref = NULL;2129		cond_resched();2130	} while ((min_bytes != U64_MAX && bytes_processed < min_bytes) ||2131		 (max_count > 0 && count < max_count) ||2132		 locked_ref);2133 2134	return 0;2135}2136 2137#ifdef SCRAMBLE_DELAYED_REFS2138/*2139 * Normally delayed refs get processed in ascending bytenr order. This2140 * correlates in most cases to the order added. To expose dependencies on this2141 * order, we start to process the tree in the middle instead of the beginning2142 */2143static u64 find_middle(struct rb_root *root)2144{2145	struct rb_node *n = root->rb_node;2146	struct btrfs_delayed_ref_node *entry;2147	int alt = 1;2148	u64 middle;2149	u64 first = 0, last = 0;2150 2151	n = rb_first(root);2152	if (n) {2153		entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);2154		first = entry->bytenr;2155	}2156	n = rb_last(root);2157	if (n) {2158		entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);2159		last = entry->bytenr;2160	}2161	n = root->rb_node;2162 2163	while (n) {2164		entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);2165		WARN_ON(!entry->in_tree);2166 2167		middle = entry->bytenr;2168 2169		if (alt)2170			n = n->rb_left;2171		else2172			n = n->rb_right;2173 2174		alt = 1 - alt;2175	}2176	return middle;2177}2178#endif2179 2180/*2181 * Start processing the delayed reference count updates and extent insertions2182 * we have queued up so far.2183 *2184 * @trans:	Transaction handle.2185 * @min_bytes:	How many bytes of delayed references to process. After this2186 *		many bytes we stop processing delayed references if there are2187 *		any more. If 0 it means to run all existing delayed references,2188 *		but not new ones added after running all existing ones.2189 *		Use (u64)-1 (U64_MAX) to run all existing delayed references2190 *		plus any new ones that are added.2191 *2192 * Returns 0 on success or if called with an aborted transaction2193 * Returns <0 on error and aborts the transaction2194 */2195int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans, u64 min_bytes)2196{2197	struct btrfs_fs_info *fs_info = trans->fs_info;2198	struct btrfs_delayed_ref_root *delayed_refs;2199	int ret;2200 2201	/* We'll clean this up in btrfs_cleanup_transaction */2202	if (TRANS_ABORTED(trans))2203		return 0;2204 2205	if (test_bit(BTRFS_FS_CREATING_FREE_SPACE_TREE, &fs_info->flags))2206		return 0;2207 2208	delayed_refs = &trans->transaction->delayed_refs;2209again:2210#ifdef SCRAMBLE_DELAYED_REFS2211	delayed_refs->run_delayed_start = find_middle(&delayed_refs->root);2212#endif2213	ret = __btrfs_run_delayed_refs(trans, min_bytes);2214	if (ret < 0) {2215		btrfs_abort_transaction(trans, ret);2216		return ret;2217	}2218 2219	if (min_bytes == U64_MAX) {2220		btrfs_create_pending_block_groups(trans);2221 2222		spin_lock(&delayed_refs->lock);2223		if (RB_EMPTY_ROOT(&delayed_refs->href_root.rb_root)) {2224			spin_unlock(&delayed_refs->lock);2225			return 0;2226		}2227		spin_unlock(&delayed_refs->lock);2228 2229		cond_resched();2230		goto again;2231	}2232 2233	return 0;2234}2235 2236int btrfs_set_disk_extent_flags(struct btrfs_trans_handle *trans,2237				struct extent_buffer *eb, u64 flags)2238{2239	struct btrfs_delayed_extent_op *extent_op;2240	int ret;2241 2242	extent_op = btrfs_alloc_delayed_extent_op();2243	if (!extent_op)2244		return -ENOMEM;2245 2246	extent_op->flags_to_set = flags;2247	extent_op->update_flags = true;2248	extent_op->update_key = false;2249 2250	ret = btrfs_add_delayed_extent_op(trans, eb->start, eb->len,2251					  btrfs_header_level(eb), extent_op);2252	if (ret)2253		btrfs_free_delayed_extent_op(extent_op);2254	return ret;2255}2256 2257static noinline int check_delayed_ref(struct btrfs_root *root,2258				      struct btrfs_path *path,2259				      u64 objectid, u64 offset, u64 bytenr)2260{2261	struct btrfs_delayed_ref_head *head;2262	struct btrfs_delayed_ref_node *ref;2263	struct btrfs_delayed_ref_root *delayed_refs;2264	struct btrfs_transaction *cur_trans;2265	struct rb_node *node;2266	int ret = 0;2267 2268	spin_lock(&root->fs_info->trans_lock);2269	cur_trans = root->fs_info->running_transaction;2270	if (cur_trans)2271		refcount_inc(&cur_trans->use_count);2272	spin_unlock(&root->fs_info->trans_lock);2273	if (!cur_trans)2274		return 0;2275 2276	delayed_refs = &cur_trans->delayed_refs;2277	spin_lock(&delayed_refs->lock);2278	head = btrfs_find_delayed_ref_head(delayed_refs, bytenr);2279	if (!head) {2280		spin_unlock(&delayed_refs->lock);2281		btrfs_put_transaction(cur_trans);2282		return 0;2283	}2284 2285	if (!mutex_trylock(&head->mutex)) {2286		if (path->nowait) {2287			spin_unlock(&delayed_refs->lock);2288			btrfs_put_transaction(cur_trans);2289			return -EAGAIN;2290		}2291 2292		refcount_inc(&head->refs);2293		spin_unlock(&delayed_refs->lock);2294 2295		btrfs_release_path(path);2296 2297		/*2298		 * Mutex was contended, block until it's released and let2299		 * caller try again2300		 */2301		mutex_lock(&head->mutex);2302		mutex_unlock(&head->mutex);2303		btrfs_put_delayed_ref_head(head);2304		btrfs_put_transaction(cur_trans);2305		return -EAGAIN;2306	}2307	spin_unlock(&delayed_refs->lock);2308 2309	spin_lock(&head->lock);2310	/*2311	 * XXX: We should replace this with a proper search function in the2312	 * future.2313	 */2314	for (node = rb_first_cached(&head->ref_tree); node;2315	     node = rb_next(node)) {2316		u64 ref_owner;2317		u64 ref_offset;2318 2319		ref = rb_entry(node, struct btrfs_delayed_ref_node, ref_node);2320		/* If it's a shared ref we know a cross reference exists */2321		if (ref->type != BTRFS_EXTENT_DATA_REF_KEY) {2322			ret = 1;2323			break;2324		}2325 2326		ref_owner = btrfs_delayed_ref_owner(ref);2327		ref_offset = btrfs_delayed_ref_offset(ref);2328 2329		/*2330		 * If our ref doesn't match the one we're currently looking at2331		 * then we have a cross reference.2332		 */2333		if (ref->ref_root != btrfs_root_id(root) ||2334		    ref_owner != objectid || ref_offset != offset) {2335			ret = 1;2336			break;2337		}2338	}2339	spin_unlock(&head->lock);2340	mutex_unlock(&head->mutex);2341	btrfs_put_transaction(cur_trans);2342	return ret;2343}2344 2345static noinline int check_committed_ref(struct btrfs_root *root,2346					struct btrfs_path *path,2347					u64 objectid, u64 offset, u64 bytenr,2348					bool strict)2349{2350	struct btrfs_fs_info *fs_info = root->fs_info;2351	struct btrfs_root *extent_root = btrfs_extent_root(fs_info, bytenr);2352	struct extent_buffer *leaf;2353	struct btrfs_extent_data_ref *ref;2354	struct btrfs_extent_inline_ref *iref;2355	struct btrfs_extent_item *ei;2356	struct btrfs_key key;2357	u32 item_size;2358	u32 expected_size;2359	int type;2360	int ret;2361 2362	key.objectid = bytenr;2363	key.offset = (u64)-1;2364	key.type = BTRFS_EXTENT_ITEM_KEY;2365 2366	ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);2367	if (ret < 0)2368		goto out;2369	if (ret == 0) {2370		/*2371		 * Key with offset -1 found, there would have to exist an extent2372		 * item with such offset, but this is out of the valid range.2373		 */2374		ret = -EUCLEAN;2375		goto out;2376	}2377 2378	ret = -ENOENT;2379	if (path->slots[0] == 0)2380		goto out;2381 2382	path->slots[0]--;2383	leaf = path->nodes[0];2384	btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);2385 2386	if (key.objectid != bytenr || key.type != BTRFS_EXTENT_ITEM_KEY)2387		goto out;2388 2389	ret = 1;2390	item_size = btrfs_item_size(leaf, path->slots[0]);2391	ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);2392	expected_size = sizeof(*ei) + btrfs_extent_inline_ref_size(BTRFS_EXTENT_DATA_REF_KEY);2393 2394	/* No inline refs; we need to bail before checking for owner ref. */2395	if (item_size == sizeof(*ei))2396		goto out;2397 2398	/* Check for an owner ref; skip over it to the real inline refs. */2399	iref = (struct btrfs_extent_inline_ref *)(ei + 1);2400	type = btrfs_get_extent_inline_ref_type(leaf, iref, BTRFS_REF_TYPE_DATA);2401	if (btrfs_fs_incompat(fs_info, SIMPLE_QUOTA) && type == BTRFS_EXTENT_OWNER_REF_KEY) {2402		expected_size += btrfs_extent_inline_ref_size(BTRFS_EXTENT_OWNER_REF_KEY);2403		iref = (struct btrfs_extent_inline_ref *)(iref + 1);2404	}2405 2406	/* If extent item has more than 1 inline ref then it's shared */2407	if (item_size != expected_size)2408		goto out;2409 2410	/*2411	 * If extent created before last snapshot => it's shared unless the2412	 * snapshot has been deleted. Use the heuristic if strict is false.2413	 */2414	if (!strict &&2415	    (btrfs_extent_generation(leaf, ei) <=2416	     btrfs_root_last_snapshot(&root->root_item)))2417		goto out;2418 2419	/* If this extent has SHARED_DATA_REF then it's shared */2420	type = btrfs_get_extent_inline_ref_type(leaf, iref, BTRFS_REF_TYPE_DATA);2421	if (type != BTRFS_EXTENT_DATA_REF_KEY)2422		goto out;2423 2424	ref = (struct btrfs_extent_data_ref *)(&iref->offset);2425	if (btrfs_extent_refs(leaf, ei) !=2426	    btrfs_extent_data_ref_count(leaf, ref) ||2427	    btrfs_extent_data_ref_root(leaf, ref) != btrfs_root_id(root) ||2428	    btrfs_extent_data_ref_objectid(leaf, ref) != objectid ||2429	    btrfs_extent_data_ref_offset(leaf, ref) != offset)2430		goto out;2431 2432	ret = 0;2433out:2434	return ret;2435}2436 2437int btrfs_cross_ref_exist(struct btrfs_root *root, u64 objectid, u64 offset,2438			  u64 bytenr, bool strict, struct btrfs_path *path)2439{2440	int ret;2441 2442	do {2443		ret = check_committed_ref(root, path, objectid,2444					  offset, bytenr, strict);2445		if (ret && ret != -ENOENT)2446			goto out;2447 2448		ret = check_delayed_ref(root, path, objectid, offset, bytenr);2449	} while (ret == -EAGAIN);2450 2451out:2452	btrfs_release_path(path);2453	if (btrfs_is_data_reloc_root(root))2454		WARN_ON(ret > 0);2455	return ret;2456}2457 2458static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,2459			   struct btrfs_root *root,2460			   struct extent_buffer *buf,2461			   int full_backref, int inc)2462{2463	struct btrfs_fs_info *fs_info = root->fs_info;2464	u64 parent;2465	u64 ref_root;2466	u32 nritems;2467	struct btrfs_key key;2468	struct btrfs_file_extent_item *fi;2469	bool for_reloc = btrfs_header_flag(buf, BTRFS_HEADER_FLAG_RELOC);2470	int i;2471	int action;2472	int level;2473	int ret = 0;2474 2475	if (btrfs_is_testing(fs_info))2476		return 0;2477 2478	ref_root = btrfs_header_owner(buf);2479	nritems = btrfs_header_nritems(buf);2480	level = btrfs_header_level(buf);2481 2482	if (!test_bit(BTRFS_ROOT_SHAREABLE, &root->state) && level == 0)2483		return 0;2484 2485	if (full_backref)2486		parent = buf->start;2487	else2488		parent = 0;2489	if (inc)2490		action = BTRFS_ADD_DELAYED_REF;2491	else2492		action = BTRFS_DROP_DELAYED_REF;2493 2494	for (i = 0; i < nritems; i++) {2495		struct btrfs_ref ref = {2496			.action = action,2497			.parent = parent,2498			.ref_root = ref_root,2499		};2500 2501		if (level == 0) {2502			btrfs_item_key_to_cpu(buf, &key, i);2503			if (key.type != BTRFS_EXTENT_DATA_KEY)2504				continue;2505			fi = btrfs_item_ptr(buf, i,2506					    struct btrfs_file_extent_item);2507			if (btrfs_file_extent_type(buf, fi) ==2508			    BTRFS_FILE_EXTENT_INLINE)2509				continue;2510			ref.bytenr = btrfs_file_extent_disk_bytenr(buf, fi);2511			if (ref.bytenr == 0)2512				continue;2513 2514			ref.num_bytes = btrfs_file_extent_disk_num_bytes(buf, fi);2515			ref.owning_root = ref_root;2516 2517			key.offset -= btrfs_file_extent_offset(buf, fi);2518			btrfs_init_data_ref(&ref, key.objectid, key.offset,2519					    btrfs_root_id(root), for_reloc);2520			if (inc)2521				ret = btrfs_inc_extent_ref(trans, &ref);2522			else2523				ret = btrfs_free_extent(trans, &ref);2524			if (ret)2525				goto fail;2526		} else {2527			/* We don't know the owning_root, leave as 0. */2528			ref.bytenr = btrfs_node_blockptr(buf, i);2529			ref.num_bytes = fs_info->nodesize;2530 2531			btrfs_init_tree_ref(&ref, level - 1,2532					    btrfs_root_id(root), for_reloc);2533			if (inc)2534				ret = btrfs_inc_extent_ref(trans, &ref);2535			else2536				ret = btrfs_free_extent(trans, &ref);2537			if (ret)2538				goto fail;2539		}2540	}2541	return 0;2542fail:2543	return ret;2544}2545 2546int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,2547		  struct extent_buffer *buf, int full_backref)2548{2549	return __btrfs_mod_ref(trans, root, buf, full_backref, 1);2550}2551 2552int btrfs_dec_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,2553		  struct extent_buffer *buf, int full_backref)2554{2555	return __btrfs_mod_ref(trans, root, buf, full_backref, 0);2556}2557 2558static u64 get_alloc_profile_by_root(struct btrfs_root *root, int data)2559{2560	struct btrfs_fs_info *fs_info = root->fs_info;2561	u64 flags;2562	u64 ret;2563 2564	if (data)2565		flags = BTRFS_BLOCK_GROUP_DATA;2566	else if (root == fs_info->chunk_root)2567		flags = BTRFS_BLOCK_GROUP_SYSTEM;2568	else2569		flags = BTRFS_BLOCK_GROUP_METADATA;2570 2571	ret = btrfs_get_alloc_profile(fs_info, flags);2572	return ret;2573}2574 2575static u64 first_logical_byte(struct btrfs_fs_info *fs_info)2576{2577	struct rb_node *leftmost;2578	u64 bytenr = 0;2579 2580	read_lock(&fs_info->block_group_cache_lock);2581	/* Get the block group with the lowest logical start address. */2582	leftmost = rb_first_cached(&fs_info->block_group_cache_tree);2583	if (leftmost) {2584		struct btrfs_block_group *bg;2585 2586		bg = rb_entry(leftmost, struct btrfs_block_group, cache_node);2587		bytenr = bg->start;2588	}2589	read_unlock(&fs_info->block_group_cache_lock);2590 2591	return bytenr;2592}2593 2594static int pin_down_extent(struct btrfs_trans_handle *trans,2595			   struct btrfs_block_group *cache,2596			   u64 bytenr, u64 num_bytes, int reserved)2597{2598	struct btrfs_fs_info *fs_info = cache->fs_info;2599 2600	spin_lock(&cache->space_info->lock);2601	spin_lock(&cache->lock);2602	cache->pinned += num_bytes;2603	btrfs_space_info_update_bytes_pinned(fs_info, cache->space_info,2604					     num_bytes);2605	if (reserved) {2606		cache->reserved -= num_bytes;2607		cache->space_info->bytes_reserved -= num_bytes;2608	}2609	spin_unlock(&cache->lock);2610	spin_unlock(&cache->space_info->lock);2611 2612	set_extent_bit(&trans->transaction->pinned_extents, bytenr,2613		       bytenr + num_bytes - 1, EXTENT_DIRTY, NULL);2614	return 0;2615}2616 2617int btrfs_pin_extent(struct btrfs_trans_handle *trans,2618		     u64 bytenr, u64 num_bytes, int reserved)2619{2620	struct btrfs_block_group *cache;2621 2622	cache = btrfs_lookup_block_group(trans->fs_info, bytenr);2623	BUG_ON(!cache); /* Logic error */2624 2625	pin_down_extent(trans, cache, bytenr, num_bytes, reserved);2626 2627	btrfs_put_block_group(cache);2628	return 0;2629}2630 2631int btrfs_pin_extent_for_log_replay(struct btrfs_trans_handle *trans,2632				    const struct extent_buffer *eb)2633{2634	struct btrfs_block_group *cache;2635	int ret;2636 2637	cache = btrfs_lookup_block_group(trans->fs_info, eb->start);2638	if (!cache)2639		return -EINVAL;2640 2641	/*2642	 * Fully cache the free space first so that our pin removes the free space2643	 * from the cache.2644	 */2645	ret = btrfs_cache_block_group(cache, true);2646	if (ret)2647		goto out;2648 2649	pin_down_extent(trans, cache, eb->start, eb->len, 0);2650 2651	/* remove us from the free space cache (if we're there at all) */2652	ret = btrfs_remove_free_space(cache, eb->start, eb->len);2653out:2654	btrfs_put_block_group(cache);2655	return ret;2656}2657 2658static int __exclude_logged_extent(struct btrfs_fs_info *fs_info,2659				   u64 start, u64 num_bytes)2660{2661	int ret;2662	struct btrfs_block_group *block_group;2663 2664	block_group = btrfs_lookup_block_group(fs_info, start);2665	if (!block_group)2666		return -EINVAL;2667 2668	ret = btrfs_cache_block_group(block_group, true);2669	if (ret)2670		goto out;2671 2672	ret = btrfs_remove_free_space(block_group, start, num_bytes);2673out:2674	btrfs_put_block_group(block_group);2675	return ret;2676}2677 2678int btrfs_exclude_logged_extents(struct extent_buffer *eb)2679{2680	struct btrfs_fs_info *fs_info = eb->fs_info;2681	struct btrfs_file_extent_item *item;2682	struct btrfs_key key;2683	int found_type;2684	int i;2685	int ret = 0;2686 2687	if (!btrfs_fs_incompat(fs_info, MIXED_GROUPS))2688		return 0;2689 2690	for (i = 0; i < btrfs_header_nritems(eb); i++) {2691		btrfs_item_key_to_cpu(eb, &key, i);2692		if (key.type != BTRFS_EXTENT_DATA_KEY)2693			continue;2694		item = btrfs_item_ptr(eb, i, struct btrfs_file_extent_item);2695		found_type = btrfs_file_extent_type(eb, item);2696		if (found_type == BTRFS_FILE_EXTENT_INLINE)2697			continue;2698		if (btrfs_file_extent_disk_bytenr(eb, item) == 0)2699			continue;2700		key.objectid = btrfs_file_extent_disk_bytenr(eb, item);2701		key.offset = btrfs_file_extent_disk_num_bytes(eb, item);2702		ret = __exclude_logged_extent(fs_info, key.objectid, key.offset);2703		if (ret)2704			break;2705	}2706 2707	return ret;2708}2709 2710static void2711btrfs_inc_block_group_reservations(struct btrfs_block_group *bg)2712{2713	atomic_inc(&bg->reservations);2714}2715 2716/*2717 * Returns the free cluster for the given space info and sets empty_cluster to2718 * what it should be based on the mount options.2719 */2720static struct btrfs_free_cluster *2721fetch_cluster_info(struct btrfs_fs_info *fs_info,2722		   struct btrfs_space_info *space_info, u64 *empty_cluster)2723{2724	struct btrfs_free_cluster *ret = NULL;2725 2726	*empty_cluster = 0;2727	if (btrfs_mixed_space_info(space_info))2728		return ret;2729 2730	if (space_info->flags & BTRFS_BLOCK_GROUP_METADATA) {2731		ret = &fs_info->meta_alloc_cluster;2732		if (btrfs_test_opt(fs_info, SSD))2733			*empty_cluster = SZ_2M;2734		else2735			*empty_cluster = SZ_64K;2736	} else if ((space_info->flags & BTRFS_BLOCK_GROUP_DATA) &&2737		   btrfs_test_opt(fs_info, SSD_SPREAD)) {2738		*empty_cluster = SZ_2M;2739		ret = &fs_info->data_alloc_cluster;2740	}2741 2742	return ret;2743}2744 2745static int unpin_extent_range(struct btrfs_fs_info *fs_info,2746			      u64 start, u64 end,2747			      const bool return_free_space)2748{2749	struct btrfs_block_group *cache = NULL;2750	struct btrfs_space_info *space_info;2751	struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;2752	struct btrfs_free_cluster *cluster = NULL;2753	u64 len;2754	u64 total_unpinned = 0;2755	u64 empty_cluster = 0;2756	bool readonly;2757	int ret = 0;2758 2759	while (start <= end) {2760		readonly = false;2761		if (!cache ||2762		    start >= cache->start + cache->length) {2763			if (cache)2764				btrfs_put_block_group(cache);2765			total_unpinned = 0;2766			cache = btrfs_lookup_block_group(fs_info, start);2767			if (cache == NULL) {2768				/* Logic error, something removed the block group. */2769				ret = -EUCLEAN;2770				goto out;2771			}2772 2773			cluster = fetch_cluster_info(fs_info,2774						     cache->space_info,2775						     &empty_cluster);2776			empty_cluster <<= 1;2777		}2778 2779		len = cache->start + cache->length - start;2780		len = min(len, end + 1 - start);2781 2782		if (return_free_space)2783			btrfs_add_free_space(cache, start, len);2784 2785		start += len;2786		total_unpinned += len;2787		space_info = cache->space_info;2788 2789		/*2790		 * If this space cluster has been marked as fragmented and we've2791		 * unpinned enough in this block group to potentially allow a2792		 * cluster to be created inside of it go ahead and clear the2793		 * fragmented check.2794		 */2795		if (cluster && cluster->fragmented &&2796		    total_unpinned > empty_cluster) {2797			spin_lock(&cluster->lock);2798			cluster->fragmented = 0;2799			spin_unlock(&cluster->lock);2800		}2801 2802		spin_lock(&space_info->lock);2803		spin_lock(&cache->lock);2804		cache->pinned -= len;2805		btrfs_space_info_update_bytes_pinned(fs_info, space_info, -len);2806		space_info->max_extent_size = 0;2807		if (cache->ro) {2808			space_info->bytes_readonly += len;2809			readonly = true;2810		} else if (btrfs_is_zoned(fs_info)) {2811			/* Need reset before reusing in a zoned block group */2812			btrfs_space_info_update_bytes_zone_unusable(fs_info, space_info,2813								    len);2814			readonly = true;2815		}2816		spin_unlock(&cache->lock);2817		if (!readonly && return_free_space &&2818		    global_rsv->space_info == space_info) {2819			spin_lock(&global_rsv->lock);2820			if (!global_rsv->full) {2821				u64 to_add = min(len, global_rsv->size -2822						      global_rsv->reserved);2823 2824				global_rsv->reserved += to_add;2825				btrfs_space_info_update_bytes_may_use(fs_info,2826						space_info, to_add);2827				if (global_rsv->reserved >= global_rsv->size)2828					global_rsv->full = 1;2829				len -= to_add;2830			}2831			spin_unlock(&global_rsv->lock);2832		}2833		/* Add to any tickets we may have */2834		if (!readonly && return_free_space && len)2835			btrfs_try_granting_tickets(fs_info, space_info);2836		spin_unlock(&space_info->lock);2837	}2838 2839	if (cache)2840		btrfs_put_block_group(cache);2841out:2842	return ret;2843}2844 2845int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans)2846{2847	struct btrfs_fs_info *fs_info = trans->fs_info;2848	struct btrfs_block_group *block_group, *tmp;2849	struct list_head *deleted_bgs;2850	struct extent_io_tree *unpin;2851	u64 start;2852	u64 end;2853	int ret;2854 2855	unpin = &trans->transaction->pinned_extents;2856 2857	while (!TRANS_ABORTED(trans)) {2858		struct extent_state *cached_state = NULL;2859 2860		mutex_lock(&fs_info->unused_bg_unpin_mutex);2861		if (!find_first_extent_bit(unpin, 0, &start, &end,2862					   EXTENT_DIRTY, &cached_state)) {2863			mutex_unlock(&fs_info->unused_bg_unpin_mutex);2864			break;2865		}2866 2867		if (btrfs_test_opt(fs_info, DISCARD_SYNC))2868			ret = btrfs_discard_extent(fs_info, start,2869						   end + 1 - start, NULL);2870 2871		clear_extent_dirty(unpin, start, end, &cached_state);2872		ret = unpin_extent_range(fs_info, start, end, true);2873		BUG_ON(ret);2874		mutex_unlock(&fs_info->unused_bg_unpin_mutex);2875		free_extent_state(cached_state);2876		cond_resched();2877	}2878 2879	if (btrfs_test_opt(fs_info, DISCARD_ASYNC)) {2880		btrfs_discard_calc_delay(&fs_info->discard_ctl);2881		btrfs_discard_schedule_work(&fs_info->discard_ctl, true);2882	}2883 2884	/*2885	 * Transaction is finished.  We don't need the lock anymore.  We2886	 * do need to clean up the block groups in case of a transaction2887	 * abort.2888	 */2889	deleted_bgs = &trans->transaction->deleted_bgs;2890	list_for_each_entry_safe(block_group, tmp, deleted_bgs, bg_list) {2891		u64 trimmed = 0;2892 2893		ret = -EROFS;2894		if (!TRANS_ABORTED(trans))2895			ret = btrfs_discard_extent(fs_info,2896						   block_group->start,2897						   block_group->length,2898						   &trimmed);2899 2900		list_del_init(&block_group->bg_list);2901		btrfs_unfreeze_block_group(block_group);2902		btrfs_put_block_group(block_group);2903 2904		if (ret) {2905			const char *errstr = btrfs_decode_error(ret);2906			btrfs_warn(fs_info,2907			   "discard failed while removing blockgroup: errno=%d %s",2908				   ret, errstr);2909		}2910	}2911 2912	return 0;2913}2914 2915/*2916 * Parse an extent item's inline extents looking for a simple quotas owner ref.2917 *2918 * @fs_info:	the btrfs_fs_info for this mount2919 * @leaf:	a leaf in the extent tree containing the extent item2920 * @slot:	the slot in the leaf where the extent item is found2921 *2922 * Returns the objectid of the root that originally allocated the extent item2923 * if the inline owner ref is expected and present, otherwise 0.2924 *2925 * If an extent item has an owner ref item, it will be the first inline ref2926 * item. Therefore the logic is to check whether there are any inline ref2927 * items, then check the type of the first one.2928 */2929u64 btrfs_get_extent_owner_root(struct btrfs_fs_info *fs_info,2930				struct extent_buffer *leaf, int slot)2931{2932	struct btrfs_extent_item *ei;2933	struct btrfs_extent_inline_ref *iref;2934	struct btrfs_extent_owner_ref *oref;2935	unsigned long ptr;2936	unsigned long end;2937	int type;2938 2939	if (!btrfs_fs_incompat(fs_info, SIMPLE_QUOTA))2940		return 0;2941 2942	ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item);2943	ptr = (unsigned long)(ei + 1);2944	end = (unsigned long)ei + btrfs_item_size(leaf, slot);2945 2946	/* No inline ref items of any kind, can't check type. */2947	if (ptr == end)2948		return 0;2949 2950	iref = (struct btrfs_extent_inline_ref *)ptr;2951	type = btrfs_get_extent_inline_ref_type(leaf, iref, BTRFS_REF_TYPE_ANY);2952 2953	/* We found an owner ref, get the root out of it. */2954	if (type == BTRFS_EXTENT_OWNER_REF_KEY) {2955		oref = (struct btrfs_extent_owner_ref *)(&iref->offset);2956		return btrfs_extent_owner_ref_root_id(leaf, oref);2957	}2958 2959	/* We have inline refs, but not an owner ref. */2960	return 0;2961}2962 2963static int do_free_extent_accounting(struct btrfs_trans_handle *trans,2964				     u64 bytenr, struct btrfs_squota_delta *delta)2965{2966	int ret;2967	u64 num_bytes = delta->num_bytes;2968 2969	if (delta->is_data) {2970		struct btrfs_root *csum_root;2971 2972		csum_root = btrfs_csum_root(trans->fs_info, bytenr);2973		ret = btrfs_del_csums(trans, csum_root, bytenr, num_bytes);2974		if (ret) {2975			btrfs_abort_transaction(trans, ret);2976			return ret;2977		}2978 2979		ret = btrfs_delete_raid_extent(trans, bytenr, num_bytes);2980		if (ret) {2981			btrfs_abort_transaction(trans, ret);2982			return ret;2983		}2984	}2985 2986	ret = btrfs_record_squota_delta(trans->fs_info, delta);2987	if (ret) {2988		btrfs_abort_transaction(trans, ret);2989		return ret;2990	}2991 2992	ret = add_to_free_space_tree(trans, bytenr, num_bytes);2993	if (ret) {2994		btrfs_abort_transaction(trans, ret);2995		return ret;2996	}2997 2998	ret = btrfs_update_block_group(trans, bytenr, num_bytes, false);2999	if (ret)3000		btrfs_abort_transaction(trans, ret);3001 3002	return ret;3003}3004 3005#define abort_and_dump(trans, path, fmt, args...)	\3006({							\3007	btrfs_abort_transaction(trans, -EUCLEAN);	\3008	btrfs_print_leaf(path->nodes[0]);		\3009	btrfs_crit(trans->fs_info, fmt, ##args);	\3010})3011 3012/*3013 * Drop one or more refs of @node.3014 *3015 * 1. Locate the extent refs.3016 *    It's either inline in EXTENT/METADATA_ITEM or in keyed SHARED_* item.3017 *    Locate it, then reduce the refs number or remove the ref line completely.3018 *3019 * 2. Update the refs count in EXTENT/METADATA_ITEM3020 *3021 * Inline backref case:3022 *3023 * in extent tree we have:3024 *3025 * 	item 0 key (13631488 EXTENT_ITEM 1048576) itemoff 16201 itemsize 823026 *		refs 2 gen 6 flags DATA3027 *		extent data backref root FS_TREE objectid 258 offset 0 count 13028 *		extent data backref root FS_TREE objectid 257 offset 0 count 13029 *3030 * This function gets called with:3031 *3032 *    node->bytenr = 136314883033 *    node->num_bytes = 10485763034 *    root_objectid = FS_TREE3035 *    owner_objectid = 2573036 *    owner_offset = 03037 *    refs_to_drop = 13038 *3039 * Then we should get some like:3040 *3041 * 	item 0 key (13631488 EXTENT_ITEM 1048576) itemoff 16201 itemsize 823042 *		refs 1 gen 6 flags DATA3043 *		extent data backref root FS_TREE objectid 258 offset 0 count 13044 *3045 * Keyed backref case:3046 *3047 * in extent tree we have:3048 *3049 *	item 0 key (13631488 EXTENT_ITEM 1048576) itemoff 3971 itemsize 243050 *		refs 754 gen 6 flags DATA3051 *	[...]3052 *	item 2 key (13631488 EXTENT_DATA_REF <HASH>) itemoff 3915 itemsize 283053 *		extent data backref root FS_TREE objectid 866 offset 0 count 13054 *3055 * This function get called with:3056 *3057 *    node->bytenr = 136314883058 *    node->num_bytes = 10485763059 *    root_objectid = FS_TREE3060 *    owner_objectid = 8663061 *    owner_offset = 03062 *    refs_to_drop = 13063 *3064 * Then we should get some like:3065 *3066 *	item 0 key (13631488 EXTENT_ITEM 1048576) itemoff 3971 itemsize 243067 *		refs 753 gen 6 flags DATA3068 *3069 * And that (13631488 EXTENT_DATA_REF <HASH>) gets removed.3070 */3071static int __btrfs_free_extent(struct btrfs_trans_handle *trans,3072			       struct btrfs_delayed_ref_head *href,3073			       struct btrfs_delayed_ref_node *node,3074			       struct btrfs_delayed_extent_op *extent_op)3075{3076	struct btrfs_fs_info *info = trans->fs_info;3077	struct btrfs_key key;3078	struct btrfs_path *path;3079	struct btrfs_root *extent_root;3080	struct extent_buffer *leaf;3081	struct btrfs_extent_item *ei;3082	struct btrfs_extent_inline_ref *iref;3083	int ret;3084	int is_data;3085	int extent_slot = 0;3086	int found_extent = 0;3087	int num_to_del = 1;3088	int refs_to_drop = node->ref_mod;3089	u32 item_size;3090	u64 refs;3091	u64 bytenr = node->bytenr;3092	u64 num_bytes = node->num_bytes;3093	u64 owner_objectid = btrfs_delayed_ref_owner(node);3094	u64 owner_offset = btrfs_delayed_ref_offset(node);3095	bool skinny_metadata = btrfs_fs_incompat(info, SKINNY_METADATA);3096	u64 delayed_ref_root = href->owning_root;3097 3098	extent_root = btrfs_extent_root(info, bytenr);3099	ASSERT(extent_root);3100 3101	path = btrfs_alloc_path();3102	if (!path)3103		return -ENOMEM;3104 3105	is_data = owner_objectid >= BTRFS_FIRST_FREE_OBJECTID;3106 3107	if (!is_data && refs_to_drop != 1) {3108		btrfs_crit(info,3109"invalid refs_to_drop, dropping more than 1 refs for tree block %llu refs_to_drop %u",3110			   node->bytenr, refs_to_drop);3111		ret = -EINVAL;3112		btrfs_abort_transaction(trans, ret);3113		goto out;3114	}3115 3116	if (is_data)3117		skinny_metadata = false;3118 3119	ret = lookup_extent_backref(trans, path, &iref, bytenr, num_bytes,3120				    node->parent, node->ref_root, owner_objectid,3121				    owner_offset);3122	if (ret == 0) {3123		/*3124		 * Either the inline backref or the SHARED_DATA_REF/3125		 * SHARED_BLOCK_REF is found3126		 *3127		 * Here is a quick path to locate EXTENT/METADATA_ITEM.3128		 * It's possible the EXTENT/METADATA_ITEM is near current slot.3129		 */3130		extent_slot = path->slots[0];3131		while (extent_slot >= 0) {3132			btrfs_item_key_to_cpu(path->nodes[0], &key,3133					      extent_slot);3134			if (key.objectid != bytenr)3135				break;3136			if (key.type == BTRFS_EXTENT_ITEM_KEY &&3137			    key.offset == num_bytes) {3138				found_extent = 1;3139				break;3140			}3141			if (key.type == BTRFS_METADATA_ITEM_KEY &&3142			    key.offset == owner_objectid) {3143				found_extent = 1;3144				break;3145			}3146 3147			/* Quick path didn't find the EXTEMT/METADATA_ITEM */3148			if (path->slots[0] - extent_slot > 5)3149				break;3150			extent_slot--;3151		}3152 3153		if (!found_extent) {3154			if (iref) {3155				abort_and_dump(trans, path,3156"invalid iref slot %u, no EXTENT/METADATA_ITEM found but has inline extent ref",3157					   path->slots[0]);3158				ret = -EUCLEAN;3159				goto out;3160			}3161			/* Must be SHARED_* item, remove the backref first */3162			ret = remove_extent_backref(trans, extent_root, path,3163						    NULL, refs_to_drop, is_data);3164			if (ret) {3165				btrfs_abort_transaction(trans, ret);3166				goto out;3167			}3168			btrfs_release_path(path);3169 3170			/* Slow path to locate EXTENT/METADATA_ITEM */3171			key.objectid = bytenr;3172			key.type = BTRFS_EXTENT_ITEM_KEY;3173			key.offset = num_bytes;3174 3175			if (!is_data && skinny_metadata) {3176				key.type = BTRFS_METADATA_ITEM_KEY;3177				key.offset = owner_objectid;3178			}3179 3180			ret = btrfs_search_slot(trans, extent_root,3181						&key, path, -1, 1);3182			if (ret > 0 && skinny_metadata && path->slots[0]) {3183				/*3184				 * Couldn't find our skinny metadata item,3185				 * see if we have ye olde extent item.3186				 */3187				path->slots[0]--;3188				btrfs_item_key_to_cpu(path->nodes[0], &key,3189						      path->slots[0]);3190				if (key.objectid == bytenr &&3191				    key.type == BTRFS_EXTENT_ITEM_KEY &&3192				    key.offset == num_bytes)3193					ret = 0;3194			}3195 3196			if (ret > 0 && skinny_metadata) {3197				skinny_metadata = false;3198				key.objectid = bytenr;3199				key.type = BTRFS_EXTENT_ITEM_KEY;3200				key.offset = num_bytes;3201				btrfs_release_path(path);3202				ret = btrfs_search_slot(trans, extent_root,3203							&key, path, -1, 1);3204			}3205 3206			if (ret) {3207				if (ret > 0)3208					btrfs_print_leaf(path->nodes[0]);3209				btrfs_err(info,3210			"umm, got %d back from search, was looking for %llu, slot %d",3211					  ret, bytenr, path->slots[0]);3212			}3213			if (ret < 0) {3214				btrfs_abort_transaction(trans, ret);3215				goto out;3216			}3217			extent_slot = path->slots[0];3218		}3219	} else if (WARN_ON(ret == -ENOENT)) {3220		abort_and_dump(trans, path,3221"unable to find ref byte nr %llu parent %llu root %llu owner %llu offset %llu slot %d",3222			       bytenr, node->parent, node->ref_root, owner_objectid,3223			       owner_offset, path->slots[0]);3224		goto out;3225	} else {3226		btrfs_abort_transaction(trans, ret);3227		goto out;3228	}3229 3230	leaf = path->nodes[0];3231	item_size = btrfs_item_size(leaf, extent_slot);3232	if (unlikely(item_size < sizeof(*ei))) {3233		ret = -EUCLEAN;3234		btrfs_err(trans->fs_info,3235			  "unexpected extent item size, has %u expect >= %zu",3236			  item_size, sizeof(*ei));3237		btrfs_abort_transaction(trans, ret);3238		goto out;3239	}3240	ei = btrfs_item_ptr(leaf, extent_slot,3241			    struct btrfs_extent_item);3242	if (owner_objectid < BTRFS_FIRST_FREE_OBJECTID &&3243	    key.type == BTRFS_EXTENT_ITEM_KEY) {3244		struct btrfs_tree_block_info *bi;3245 3246		if (item_size < sizeof(*ei) + sizeof(*bi)) {3247			abort_and_dump(trans, path,3248"invalid extent item size for key (%llu, %u, %llu) slot %u owner %llu, has %u expect >= %zu",3249				       key.objectid, key.type, key.offset,3250				       path->slots[0], owner_objectid, item_size,3251				       sizeof(*ei) + sizeof(*bi));3252			ret = -EUCLEAN;3253			goto out;3254		}3255		bi = (struct btrfs_tree_block_info *)(ei + 1);3256		WARN_ON(owner_objectid != btrfs_tree_block_level(leaf, bi));3257	}3258 3259	refs = btrfs_extent_refs(leaf, ei);3260	if (refs < refs_to_drop) {3261		abort_and_dump(trans, path,3262		"trying to drop %d refs but we only have %llu for bytenr %llu slot %u",3263			       refs_to_drop, refs, bytenr, path->slots[0]);3264		ret = -EUCLEAN;3265		goto out;3266	}3267	refs -= refs_to_drop;3268 3269	if (refs > 0) {3270		if (extent_op)3271			__run_delayed_extent_op(extent_op, leaf, ei);3272		/*3273		 * In the case of inline back ref, reference count will3274		 * be updated by remove_extent_backref3275		 */3276		if (iref) {3277			if (!found_extent) {3278				abort_and_dump(trans, path,3279"invalid iref, got inlined extent ref but no EXTENT/METADATA_ITEM found, slot %u",3280					       path->slots[0]);3281				ret = -EUCLEAN;3282				goto out;3283			}3284		} else {3285			btrfs_set_extent_refs(leaf, ei, refs);3286			btrfs_mark_buffer_dirty(trans, leaf);3287		}3288		if (found_extent) {3289			ret = remove_extent_backref(trans, extent_root, path,3290						    iref, refs_to_drop, is_data);3291			if (ret) {3292				btrfs_abort_transaction(trans, ret);3293				goto out;3294			}3295		}3296	} else {3297		struct btrfs_squota_delta delta = {3298			.root = delayed_ref_root,3299			.num_bytes = num_bytes,3300			.is_data = is_data,3301			.is_inc = false,3302			.generation = btrfs_extent_generation(leaf, ei),3303		};3304 3305		/* In this branch refs == 1 */3306		if (found_extent) {3307			if (is_data && refs_to_drop !=3308			    extent_data_ref_count(path, iref)) {3309				abort_and_dump(trans, path,3310		"invalid refs_to_drop, current refs %u refs_to_drop %u slot %u",3311					       extent_data_ref_count(path, iref),3312					       refs_to_drop, path->slots[0]);3313				ret = -EUCLEAN;3314				goto out;3315			}3316			if (iref) {3317				if (path->slots[0] != extent_slot) {3318					abort_and_dump(trans, path,3319"invalid iref, extent item key (%llu %u %llu) slot %u doesn't have wanted iref",3320						       key.objectid, key.type,3321						       key.offset, path->slots[0]);3322					ret = -EUCLEAN;3323					goto out;3324				}3325			} else {3326				/*3327				 * No inline ref, we must be at SHARED_* item,3328				 * And it's single ref, it must be:3329				 * |	extent_slot	  ||extent_slot + 1|3330				 * [ EXTENT/METADATA_ITEM ][ SHARED_* ITEM ]3331				 */3332				if (path->slots[0] != extent_slot + 1) {3333					abort_and_dump(trans, path,3334	"invalid SHARED_* item slot %u, previous item is not EXTENT/METADATA_ITEM",3335						       path->slots[0]);3336					ret = -EUCLEAN;3337					goto out;3338				}3339				path->slots[0] = extent_slot;3340				num_to_del = 2;3341			}3342		}3343		/*3344		 * We can't infer the data owner from the delayed ref, so we need3345		 * to try to get it from the owning ref item.3346		 *3347		 * If it is not present, then that extent was not written under3348		 * simple quotas mode, so we don't need to account for its deletion.3349		 */3350		if (is_data)3351			delta.root = btrfs_get_extent_owner_root(trans->fs_info,3352								 leaf, extent_slot);3353 3354		ret = btrfs_del_items(trans, extent_root, path, path->slots[0],3355				      num_to_del);3356		if (ret) {3357			btrfs_abort_transaction(trans, ret);3358			goto out;3359		}3360		btrfs_release_path(path);3361 3362		ret = do_free_extent_accounting(trans, bytenr, &delta);3363	}3364	btrfs_release_path(path);3365 3366out:3367	btrfs_free_path(path);3368	return ret;3369}3370 3371/*3372 * when we free an block, it is possible (and likely) that we free the last3373 * delayed ref for that extent as well.  This searches the delayed ref tree for3374 * a given extent, and if there are no other delayed refs to be processed, it3375 * removes it from the tree.3376 */3377static noinline int check_ref_cleanup(struct btrfs_trans_handle *trans,3378				      u64 bytenr)3379{3380	struct btrfs_delayed_ref_head *head;3381	struct btrfs_delayed_ref_root *delayed_refs;3382	int ret = 0;3383 3384	delayed_refs = &trans->transaction->delayed_refs;3385	spin_lock(&delayed_refs->lock);3386	head = btrfs_find_delayed_ref_head(delayed_refs, bytenr);3387	if (!head)3388		goto out_delayed_unlock;3389 3390	spin_lock(&head->lock);3391	if (!RB_EMPTY_ROOT(&head->ref_tree.rb_root))3392		goto out;3393 3394	if (cleanup_extent_op(head) != NULL)3395		goto out;3396 3397	/*3398	 * waiting for the lock here would deadlock.  If someone else has it3399	 * locked they are already in the process of dropping it anyway3400	 */3401	if (!mutex_trylock(&head->mutex))3402		goto out;3403 3404	btrfs_delete_ref_head(delayed_refs, head);3405	head->processing = false;3406 3407	spin_unlock(&head->lock);3408	spin_unlock(&delayed_refs->lock);3409 3410	BUG_ON(head->extent_op);3411	if (head->must_insert_reserved)3412		ret = 1;3413 3414	btrfs_cleanup_ref_head_accounting(trans->fs_info, delayed_refs, head);3415	mutex_unlock(&head->mutex);3416	btrfs_put_delayed_ref_head(head);3417	return ret;3418out:3419	spin_unlock(&head->lock);3420 3421out_delayed_unlock:3422	spin_unlock(&delayed_refs->lock);3423	return 0;3424}3425 3426int btrfs_free_tree_block(struct btrfs_trans_handle *trans,3427			  u64 root_id,3428			  struct extent_buffer *buf,3429			  u64 parent, int last_ref)3430{3431	struct btrfs_fs_info *fs_info = trans->fs_info;3432	struct btrfs_block_group *bg;3433	int ret;3434 3435	if (root_id != BTRFS_TREE_LOG_OBJECTID) {3436		struct btrfs_ref generic_ref = {3437			.action = BTRFS_DROP_DELAYED_REF,3438			.bytenr = buf->start,3439			.num_bytes = buf->len,3440			.parent = parent,3441			.owning_root = btrfs_header_owner(buf),3442			.ref_root = root_id,3443		};3444 3445		/*3446		 * Assert that the extent buffer is not cleared due to3447		 * EXTENT_BUFFER_ZONED_ZEROOUT. Please refer3448		 * btrfs_clear_buffer_dirty() and btree_csum_one_bio() for3449		 * detail.3450		 */3451		ASSERT(btrfs_header_bytenr(buf) != 0);3452 3453		btrfs_init_tree_ref(&generic_ref, btrfs_header_level(buf), 0, false);3454		btrfs_ref_tree_mod(fs_info, &generic_ref);3455		ret = btrfs_add_delayed_tree_ref(trans, &generic_ref, NULL);3456		if (ret < 0)3457			return ret;3458	}3459 3460	if (!last_ref)3461		return 0;3462 3463	if (btrfs_header_generation(buf) != trans->transid)3464		goto out;3465 3466	if (root_id != BTRFS_TREE_LOG_OBJECTID) {3467		ret = check_ref_cleanup(trans, buf->start);3468		if (!ret)3469			goto out;3470	}3471 3472	bg = btrfs_lookup_block_group(fs_info, buf->start);3473 3474	if (btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {3475		pin_down_extent(trans, bg, buf->start, buf->len, 1);3476		btrfs_put_block_group(bg);3477		goto out;3478	}3479 3480	/*3481	 * If there are tree mod log users we may have recorded mod log3482	 * operations for this node.  If we re-allocate this node we3483	 * could replay operations on this node that happened when it3484	 * existed in a completely different root.  For example if it3485	 * was part of root A, then was reallocated to root B, and we3486	 * are doing a btrfs_old_search_slot(root b), we could replay3487	 * operations that happened when the block was part of root A,3488	 * giving us an inconsistent view of the btree.3489	 *3490	 * We are safe from races here because at this point no other3491	 * node or root points to this extent buffer, so if after this3492	 * check a new tree mod log user joins we will not have an3493	 * existing log of operations on this node that we have to3494	 * contend with.3495	 */3496 3497	if (test_bit(BTRFS_FS_TREE_MOD_LOG_USERS, &fs_info->flags)3498		     || btrfs_is_zoned(fs_info)) {3499		pin_down_extent(trans, bg, buf->start, buf->len, 1);3500		btrfs_put_block_group(bg);3501		goto out;3502	}3503 3504	WARN_ON(test_bit(EXTENT_BUFFER_DIRTY, &buf->bflags));3505 3506	btrfs_add_free_space(bg, buf->start, buf->len);3507	btrfs_free_reserved_bytes(bg, buf->len, 0);3508	btrfs_put_block_group(bg);3509	trace_btrfs_reserved_extent_free(fs_info, buf->start, buf->len);3510 3511out:3512 3513	/*3514	 * Deleting the buffer, clear the corrupt flag since it doesn't3515	 * matter anymore.3516	 */3517	clear_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags);3518	return 0;3519}3520 3521/* Can return -ENOMEM */3522int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_ref *ref)3523{3524	struct btrfs_fs_info *fs_info = trans->fs_info;3525	int ret;3526 3527	if (btrfs_is_testing(fs_info))3528		return 0;3529 3530	/*3531	 * tree log blocks never actually go into the extent allocation3532	 * tree, just update pinning info and exit early.3533	 */3534	if (ref->ref_root == BTRFS_TREE_LOG_OBJECTID) {3535		btrfs_pin_extent(trans, ref->bytenr, ref->num_bytes, 1);3536		ret = 0;3537	} else if (ref->type == BTRFS_REF_METADATA) {3538		ret = btrfs_add_delayed_tree_ref(trans, ref, NULL);3539	} else {3540		ret = btrfs_add_delayed_data_ref(trans, ref, 0);3541	}3542 3543	if (ref->ref_root != BTRFS_TREE_LOG_OBJECTID)3544		btrfs_ref_tree_mod(fs_info, ref);3545 3546	return ret;3547}3548 3549enum btrfs_loop_type {3550	/*3551	 * Start caching block groups but do not wait for progress or for them3552	 * to be done.3553	 */3554	LOOP_CACHING_NOWAIT,3555 3556	/*3557	 * Wait for the block group free_space >= the space we're waiting for if3558	 * the block group isn't cached.3559	 */3560	LOOP_CACHING_WAIT,3561 3562	/*3563	 * Allow allocations to happen from block groups that do not yet have a3564	 * size classification.3565	 */3566	LOOP_UNSET_SIZE_CLASS,3567 3568	/*3569	 * Allocate a chunk and then retry the allocation.3570	 */3571	LOOP_ALLOC_CHUNK,3572 3573	/*3574	 * Ignore the size class restrictions for this allocation.3575	 */3576	LOOP_WRONG_SIZE_CLASS,3577 3578	/*3579	 * Ignore the empty size, only try to allocate the number of bytes3580	 * needed for this allocation.3581	 */3582	LOOP_NO_EMPTY_SIZE,3583};3584 3585static inline void3586btrfs_lock_block_group(struct btrfs_block_group *cache,3587		       int delalloc)3588{3589	if (delalloc)3590		down_read(&cache->data_rwsem);3591}3592 3593static inline void btrfs_grab_block_group(struct btrfs_block_group *cache,3594		       int delalloc)3595{3596	btrfs_get_block_group(cache);3597	if (delalloc)3598		down_read(&cache->data_rwsem);3599}3600 3601static struct btrfs_block_group *btrfs_lock_cluster(3602		   struct btrfs_block_group *block_group,3603		   struct btrfs_free_cluster *cluster,3604		   int delalloc)3605	__acquires(&cluster->refill_lock)3606{3607	struct btrfs_block_group *used_bg = NULL;3608 3609	spin_lock(&cluster->refill_lock);3610	while (1) {3611		used_bg = cluster->block_group;3612		if (!used_bg)3613			return NULL;3614 3615		if (used_bg == block_group)3616			return used_bg;3617 3618		btrfs_get_block_group(used_bg);3619 3620		if (!delalloc)3621			return used_bg;3622 3623		if (down_read_trylock(&used_bg->data_rwsem))3624			return used_bg;3625 3626		spin_unlock(&cluster->refill_lock);3627 3628		/* We should only have one-level nested. */3629		down_read_nested(&used_bg->data_rwsem, SINGLE_DEPTH_NESTING);3630 3631		spin_lock(&cluster->refill_lock);3632		if (used_bg == cluster->block_group)3633			return used_bg;3634 3635		up_read(&used_bg->data_rwsem);3636		btrfs_put_block_group(used_bg);3637	}3638}3639 3640static inline void3641btrfs_release_block_group(struct btrfs_block_group *cache,3642			 int delalloc)3643{3644	if (delalloc)3645		up_read(&cache->data_rwsem);3646	btrfs_put_block_group(cache);3647}3648 3649/*3650 * Helper function for find_free_extent().3651 *3652 * Return -ENOENT to inform caller that we need fallback to unclustered mode.3653 * Return >0 to inform caller that we find nothing3654 * Return 0 means we have found a location and set ffe_ctl->found_offset.3655 */3656static int find_free_extent_clustered(struct btrfs_block_group *bg,3657				      struct find_free_extent_ctl *ffe_ctl,3658				      struct btrfs_block_group **cluster_bg_ret)3659{3660	struct btrfs_block_group *cluster_bg;3661	struct btrfs_free_cluster *last_ptr = ffe_ctl->last_ptr;3662	u64 aligned_cluster;3663	u64 offset;3664	int ret;3665 3666	cluster_bg = btrfs_lock_cluster(bg, last_ptr, ffe_ctl->delalloc);3667	if (!cluster_bg)3668		goto refill_cluster;3669	if (cluster_bg != bg && (cluster_bg->ro ||3670	    !block_group_bits(cluster_bg, ffe_ctl->flags)))3671		goto release_cluster;3672 3673	offset = btrfs_alloc_from_cluster(cluster_bg, last_ptr,3674			ffe_ctl->num_bytes, cluster_bg->start,3675			&ffe_ctl->max_extent_size);3676	if (offset) {3677		/* We have a block, we're done */3678		spin_unlock(&last_ptr->refill_lock);3679		trace_btrfs_reserve_extent_cluster(cluster_bg, ffe_ctl);3680		*cluster_bg_ret = cluster_bg;3681		ffe_ctl->found_offset = offset;3682		return 0;3683	}3684	WARN_ON(last_ptr->block_group != cluster_bg);3685 3686release_cluster:3687	/*3688	 * If we are on LOOP_NO_EMPTY_SIZE, we can't set up a new clusters, so3689	 * lets just skip it and let the allocator find whatever block it can3690	 * find. If we reach this point, we will have tried the cluster3691	 * allocator plenty of times and not have found anything, so we are3692	 * likely way too fragmented for the clustering stuff to find anything.3693	 *3694	 * However, if the cluster is taken from the current block group,3695	 * release the cluster first, so that we stand a better chance of3696	 * succeeding in the unclustered allocation.3697	 */3698	if (ffe_ctl->loop >= LOOP_NO_EMPTY_SIZE && cluster_bg != bg) {3699		spin_unlock(&last_ptr->refill_lock);3700		btrfs_release_block_group(cluster_bg, ffe_ctl->delalloc);3701		return -ENOENT;3702	}3703 3704	/* This cluster didn't work out, free it and start over */3705	btrfs_return_cluster_to_free_space(NULL, last_ptr);3706 3707	if (cluster_bg != bg)3708		btrfs_release_block_group(cluster_bg, ffe_ctl->delalloc);3709 3710refill_cluster:3711	if (ffe_ctl->loop >= LOOP_NO_EMPTY_SIZE) {3712		spin_unlock(&last_ptr->refill_lock);3713		return -ENOENT;3714	}3715 3716	aligned_cluster = max_t(u64,3717			ffe_ctl->empty_cluster + ffe_ctl->empty_size,3718			bg->full_stripe_len);3719	ret = btrfs_find_space_cluster(bg, last_ptr, ffe_ctl->search_start,3720			ffe_ctl->num_bytes, aligned_cluster);3721	if (ret == 0) {3722		/* Now pull our allocation out of this cluster */3723		offset = btrfs_alloc_from_cluster(bg, last_ptr,3724				ffe_ctl->num_bytes, ffe_ctl->search_start,3725				&ffe_ctl->max_extent_size);3726		if (offset) {3727			/* We found one, proceed */3728			spin_unlock(&last_ptr->refill_lock);3729			ffe_ctl->found_offset = offset;3730			trace_btrfs_reserve_extent_cluster(bg, ffe_ctl);3731			return 0;3732		}3733	}3734	/*3735	 * At this point we either didn't find a cluster or we weren't able to3736	 * allocate a block from our cluster.  Free the cluster we've been3737	 * trying to use, and go to the next block group.3738	 */3739	btrfs_return_cluster_to_free_space(NULL, last_ptr);3740	spin_unlock(&last_ptr->refill_lock);3741	return 1;3742}3743 3744/*3745 * Return >0 to inform caller that we find nothing3746 * Return 0 when we found an free extent and set ffe_ctrl->found_offset3747 */3748static int find_free_extent_unclustered(struct btrfs_block_group *bg,3749					struct find_free_extent_ctl *ffe_ctl)3750{3751	struct btrfs_free_cluster *last_ptr = ffe_ctl->last_ptr;3752	u64 offset;3753 3754	/*3755	 * We are doing an unclustered allocation, set the fragmented flag so3756	 * we don't bother trying to setup a cluster again until we get more3757	 * space.3758	 */3759	if (unlikely(last_ptr)) {3760		spin_lock(&last_ptr->lock);3761		last_ptr->fragmented = 1;3762		spin_unlock(&last_ptr->lock);3763	}3764	if (ffe_ctl->cached) {3765		struct btrfs_free_space_ctl *free_space_ctl;3766 3767		free_space_ctl = bg->free_space_ctl;3768		spin_lock(&free_space_ctl->tree_lock);3769		if (free_space_ctl->free_space <3770		    ffe_ctl->num_bytes + ffe_ctl->empty_cluster +3771		    ffe_ctl->empty_size) {3772			ffe_ctl->total_free_space = max_t(u64,3773					ffe_ctl->total_free_space,3774					free_space_ctl->free_space);3775			spin_unlock(&free_space_ctl->tree_lock);3776			return 1;3777		}3778		spin_unlock(&free_space_ctl->tree_lock);3779	}3780 3781	offset = btrfs_find_space_for_alloc(bg, ffe_ctl->search_start,3782			ffe_ctl->num_bytes, ffe_ctl->empty_size,3783			&ffe_ctl->max_extent_size);3784	if (!offset)3785		return 1;3786	ffe_ctl->found_offset = offset;3787	return 0;3788}3789 3790static int do_allocation_clustered(struct btrfs_block_group *block_group,3791				   struct find_free_extent_ctl *ffe_ctl,3792				   struct btrfs_block_group **bg_ret)3793{3794	int ret;3795 3796	/* We want to try and use the cluster allocator, so lets look there */3797	if (ffe_ctl->last_ptr && ffe_ctl->use_cluster) {3798		ret = find_free_extent_clustered(block_group, ffe_ctl, bg_ret);3799		if (ret >= 0)3800			return ret;3801		/* ret == -ENOENT case falls through */3802	}3803 3804	return find_free_extent_unclustered(block_group, ffe_ctl);3805}3806 3807/*3808 * Tree-log block group locking3809 * ============================3810 *3811 * fs_info::treelog_bg_lock protects the fs_info::treelog_bg which3812 * indicates the starting address of a block group, which is reserved only3813 * for tree-log metadata.3814 *3815 * Lock nesting3816 * ============3817 *3818 * space_info::lock3819 *   block_group::lock3820 *     fs_info::treelog_bg_lock3821 */3822 3823/*3824 * Simple allocator for sequential-only block group. It only allows sequential3825 * allocation. No need to play with trees. This function also reserves the3826 * bytes as in btrfs_add_reserved_bytes.3827 */3828static int do_allocation_zoned(struct btrfs_block_group *block_group,3829			       struct find_free_extent_ctl *ffe_ctl,3830			       struct btrfs_block_group **bg_ret)3831{3832	struct btrfs_fs_info *fs_info = block_group->fs_info;3833	struct btrfs_space_info *space_info = block_group->space_info;3834	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;3835	u64 start = block_group->start;3836	u64 num_bytes = ffe_ctl->num_bytes;3837	u64 avail;3838	u64 bytenr = block_group->start;3839	u64 log_bytenr;3840	u64 data_reloc_bytenr;3841	int ret = 0;3842	bool skip = false;3843 3844	ASSERT(btrfs_is_zoned(block_group->fs_info));3845 3846	/*3847	 * Do not allow non-tree-log blocks in the dedicated tree-log block3848	 * group, and vice versa.3849	 */3850	spin_lock(&fs_info->treelog_bg_lock);3851	log_bytenr = fs_info->treelog_bg;3852	if (log_bytenr && ((ffe_ctl->for_treelog && bytenr != log_bytenr) ||3853			   (!ffe_ctl->for_treelog && bytenr == log_bytenr)))3854		skip = true;3855	spin_unlock(&fs_info->treelog_bg_lock);3856	if (skip)3857		return 1;3858 3859	/*3860	 * Do not allow non-relocation blocks in the dedicated relocation block3861	 * group, and vice versa.3862	 */3863	spin_lock(&fs_info->relocation_bg_lock);3864	data_reloc_bytenr = fs_info->data_reloc_bg;3865	if (data_reloc_bytenr &&3866	    ((ffe_ctl->for_data_reloc && bytenr != data_reloc_bytenr) ||3867	     (!ffe_ctl->for_data_reloc && bytenr == data_reloc_bytenr)))3868		skip = true;3869	spin_unlock(&fs_info->relocation_bg_lock);3870	if (skip)3871		return 1;3872 3873	/* Check RO and no space case before trying to activate it */3874	spin_lock(&block_group->lock);3875	if (block_group->ro || btrfs_zoned_bg_is_full(block_group)) {3876		ret = 1;3877		/*3878		 * May need to clear fs_info->{treelog,data_reloc}_bg.3879		 * Return the error after taking the locks.3880		 */3881	}3882	spin_unlock(&block_group->lock);3883 3884	/* Metadata block group is activated at write time. */3885	if (!ret && (block_group->flags & BTRFS_BLOCK_GROUP_DATA) &&3886	    !btrfs_zone_activate(block_group)) {3887		ret = 1;3888		/*3889		 * May need to clear fs_info->{treelog,data_reloc}_bg.3890		 * Return the error after taking the locks.3891		 */3892	}3893 3894	spin_lock(&space_info->lock);3895	spin_lock(&block_group->lock);3896	spin_lock(&fs_info->treelog_bg_lock);3897	spin_lock(&fs_info->relocation_bg_lock);3898 3899	if (ret)3900		goto out;3901 3902	ASSERT(!ffe_ctl->for_treelog ||3903	       block_group->start == fs_info->treelog_bg ||3904	       fs_info->treelog_bg == 0);3905	ASSERT(!ffe_ctl->for_data_reloc ||3906	       block_group->start == fs_info->data_reloc_bg ||3907	       fs_info->data_reloc_bg == 0);3908 3909	if (block_group->ro ||3910	    (!ffe_ctl->for_data_reloc &&3911	     test_bit(BLOCK_GROUP_FLAG_ZONED_DATA_RELOC, &block_group->runtime_flags))) {3912		ret = 1;3913		goto out;3914	}3915 3916	/*3917	 * Do not allow currently using block group to be tree-log dedicated3918	 * block group.3919	 */3920	if (ffe_ctl->for_treelog && !fs_info->treelog_bg &&3921	    (block_group->used || block_group->reserved)) {3922		ret = 1;3923		goto out;3924	}3925 3926	/*3927	 * Do not allow currently used block group to be the data relocation3928	 * dedicated block group.3929	 */3930	if (ffe_ctl->for_data_reloc && !fs_info->data_reloc_bg &&3931	    (block_group->used || block_group->reserved)) {3932		ret = 1;3933		goto out;3934	}3935 3936	WARN_ON_ONCE(block_group->alloc_offset > block_group->zone_capacity);3937	avail = block_group->zone_capacity - block_group->alloc_offset;3938	if (avail < num_bytes) {3939		if (ffe_ctl->max_extent_size < avail) {3940			/*3941			 * With sequential allocator, free space is always3942			 * contiguous3943			 */3944			ffe_ctl->max_extent_size = avail;3945			ffe_ctl->total_free_space = avail;3946		}3947		ret = 1;3948		goto out;3949	}3950 3951	if (ffe_ctl->for_treelog && !fs_info->treelog_bg)3952		fs_info->treelog_bg = block_group->start;3953 3954	if (ffe_ctl->for_data_reloc) {3955		if (!fs_info->data_reloc_bg)3956			fs_info->data_reloc_bg = block_group->start;3957		/*3958		 * Do not allow allocations from this block group, unless it is3959		 * for data relocation. Compared to increasing the ->ro, setting3960		 * the ->zoned_data_reloc_ongoing flag still allows nocow3961		 * writers to come in. See btrfs_inc_nocow_writers().3962		 *3963		 * We need to disable an allocation to avoid an allocation of3964		 * regular (non-relocation data) extent. With mix of relocation3965		 * extents and regular extents, we can dispatch WRITE commands3966		 * (for relocation extents) and ZONE APPEND commands (for3967		 * regular extents) at the same time to the same zone, which3968		 * easily break the write pointer.3969		 *3970		 * Also, this flag avoids this block group to be zone finished.3971		 */3972		set_bit(BLOCK_GROUP_FLAG_ZONED_DATA_RELOC, &block_group->runtime_flags);3973	}3974 3975	ffe_ctl->found_offset = start + block_group->alloc_offset;3976	block_group->alloc_offset += num_bytes;3977	spin_lock(&ctl->tree_lock);3978	ctl->free_space -= num_bytes;3979	spin_unlock(&ctl->tree_lock);3980 3981	/*3982	 * We do not check if found_offset is aligned to stripesize. The3983	 * address is anyway rewritten when using zone append writing.3984	 */3985 3986	ffe_ctl->search_start = ffe_ctl->found_offset;3987 3988out:3989	if (ret && ffe_ctl->for_treelog)3990		fs_info->treelog_bg = 0;3991	if (ret && ffe_ctl->for_data_reloc)3992		fs_info->data_reloc_bg = 0;3993	spin_unlock(&fs_info->relocation_bg_lock);3994	spin_unlock(&fs_info->treelog_bg_lock);3995	spin_unlock(&block_group->lock);3996	spin_unlock(&space_info->lock);3997	return ret;3998}3999 4000static int do_allocation(struct btrfs_block_group *block_group,4001			 struct find_free_extent_ctl *ffe_ctl,4002			 struct btrfs_block_group **bg_ret)4003{4004	switch (ffe_ctl->policy) {4005	case BTRFS_EXTENT_ALLOC_CLUSTERED:4006		return do_allocation_clustered(block_group, ffe_ctl, bg_ret);4007	case BTRFS_EXTENT_ALLOC_ZONED:4008		return do_allocation_zoned(block_group, ffe_ctl, bg_ret);4009	default:4010		BUG();4011	}4012}4013 4014static void release_block_group(struct btrfs_block_group *block_group,4015				struct find_free_extent_ctl *ffe_ctl,4016				int delalloc)4017{4018	switch (ffe_ctl->policy) {4019	case BTRFS_EXTENT_ALLOC_CLUSTERED:4020		ffe_ctl->retry_uncached = false;4021		break;4022	case BTRFS_EXTENT_ALLOC_ZONED:4023		/* Nothing to do */4024		break;4025	default:4026		BUG();4027	}4028 4029	BUG_ON(btrfs_bg_flags_to_raid_index(block_group->flags) !=4030	       ffe_ctl->index);4031	btrfs_release_block_group(block_group, delalloc);4032}4033 4034static void found_extent_clustered(struct find_free_extent_ctl *ffe_ctl,4035				   struct btrfs_key *ins)4036{4037	struct btrfs_free_cluster *last_ptr = ffe_ctl->last_ptr;4038 4039	if (!ffe_ctl->use_cluster && last_ptr) {4040		spin_lock(&last_ptr->lock);4041		last_ptr->window_start = ins->objectid;4042		spin_unlock(&last_ptr->lock);4043	}4044}4045 4046static void found_extent(struct find_free_extent_ctl *ffe_ctl,4047			 struct btrfs_key *ins)4048{4049	switch (ffe_ctl->policy) {4050	case BTRFS_EXTENT_ALLOC_CLUSTERED:4051		found_extent_clustered(ffe_ctl, ins);4052		break;4053	case BTRFS_EXTENT_ALLOC_ZONED:4054		/* Nothing to do */4055		break;4056	default:4057		BUG();4058	}4059}4060 4061static int can_allocate_chunk_zoned(struct btrfs_fs_info *fs_info,4062				    struct find_free_extent_ctl *ffe_ctl)4063{4064	/* Block group's activeness is not a requirement for METADATA block groups. */4065	if (!(ffe_ctl->flags & BTRFS_BLOCK_GROUP_DATA))4066		return 0;4067 4068	/* If we can activate new zone, just allocate a chunk and use it */4069	if (btrfs_can_activate_zone(fs_info->fs_devices, ffe_ctl->flags))4070		return 0;4071 4072	/*4073	 * We already reached the max active zones. Try to finish one block4074	 * group to make a room for a new block group. This is only possible4075	 * for a data block group because btrfs_zone_finish() may need to wait4076	 * for a running transaction which can cause a deadlock for metadata4077	 * allocation.4078	 */4079	if (ffe_ctl->flags & BTRFS_BLOCK_GROUP_DATA) {4080		int ret = btrfs_zone_finish_one_bg(fs_info);4081 4082		if (ret == 1)4083			return 0;4084		else if (ret < 0)4085			return ret;4086	}4087 4088	/*4089	 * If we have enough free space left in an already active block group4090	 * and we can't activate any other zone now, do not allow allocating a4091	 * new chunk and let find_free_extent() retry with a smaller size.4092	 */4093	if (ffe_ctl->max_extent_size >= ffe_ctl->min_alloc_size)4094		return -ENOSPC;4095 4096	/*4097	 * Even min_alloc_size is not left in any block groups. Since we cannot4098	 * activate a new block group, allocating it may not help. Let's tell a4099	 * caller to try again and hope it progress something by writing some4100	 * parts of the region. That is only possible for data block groups,4101	 * where a part of the region can be written.4102	 */4103	if (ffe_ctl->flags & BTRFS_BLOCK_GROUP_DATA)4104		return -EAGAIN;4105 4106	/*4107	 * We cannot activate a new block group and no enough space left in any4108	 * block groups. So, allocating a new block group may not help. But,4109	 * there is nothing to do anyway, so let's go with it.4110	 */4111	return 0;4112}4113 4114static int can_allocate_chunk(struct btrfs_fs_info *fs_info,4115			      struct find_free_extent_ctl *ffe_ctl)4116{4117	switch (ffe_ctl->policy) {4118	case BTRFS_EXTENT_ALLOC_CLUSTERED:4119		return 0;4120	case BTRFS_EXTENT_ALLOC_ZONED:4121		return can_allocate_chunk_zoned(fs_info, ffe_ctl);4122	default:4123		BUG();4124	}4125}4126 4127/*4128 * Return >0 means caller needs to re-search for free extent4129 * Return 0 means we have the needed free extent.4130 * Return <0 means we failed to locate any free extent.4131 */4132static int find_free_extent_update_loop(struct btrfs_fs_info *fs_info,4133					struct btrfs_key *ins,4134					struct find_free_extent_ctl *ffe_ctl,4135					bool full_search)4136{4137	struct btrfs_root *root = fs_info->chunk_root;4138	int ret;4139 4140	if ((ffe_ctl->loop == LOOP_CACHING_NOWAIT) &&4141	    ffe_ctl->have_caching_bg && !ffe_ctl->orig_have_caching_bg)4142		ffe_ctl->orig_have_caching_bg = true;4143 4144	if (ins->objectid) {4145		found_extent(ffe_ctl, ins);4146		return 0;4147	}4148 4149	if (ffe_ctl->loop >= LOOP_CACHING_WAIT && ffe_ctl->have_caching_bg)4150		return 1;4151 4152	ffe_ctl->index++;4153	if (ffe_ctl->index < BTRFS_NR_RAID_TYPES)4154		return 1;4155 4156	/* See the comments for btrfs_loop_type for an explanation of the phases. */4157	if (ffe_ctl->loop < LOOP_NO_EMPTY_SIZE) {4158		ffe_ctl->index = 0;4159		/*4160		 * We want to skip the LOOP_CACHING_WAIT step if we don't have4161		 * any uncached bgs and we've already done a full search4162		 * through.4163		 */4164		if (ffe_ctl->loop == LOOP_CACHING_NOWAIT &&4165		    (!ffe_ctl->orig_have_caching_bg && full_search))4166			ffe_ctl->loop++;4167		ffe_ctl->loop++;4168 4169		if (ffe_ctl->loop == LOOP_ALLOC_CHUNK) {4170			struct btrfs_trans_handle *trans;4171			int exist = 0;4172 4173			/* Check if allocation policy allows to create a new chunk */4174			ret = can_allocate_chunk(fs_info, ffe_ctl);4175			if (ret)4176				return ret;4177 4178			trans = current->journal_info;4179			if (trans)4180				exist = 1;4181			else4182				trans = btrfs_join_transaction(root);4183 4184			if (IS_ERR(trans)) {4185				ret = PTR_ERR(trans);4186				return ret;4187			}4188 4189			ret = btrfs_chunk_alloc(trans, ffe_ctl->flags,4190						CHUNK_ALLOC_FORCE_FOR_EXTENT);4191 4192			/* Do not bail out on ENOSPC since we can do more. */4193			if (ret == -ENOSPC) {4194				ret = 0;4195				ffe_ctl->loop++;4196			}4197			else if (ret < 0)4198				btrfs_abort_transaction(trans, ret);4199			else4200				ret = 0;4201			if (!exist)4202				btrfs_end_transaction(trans);4203			if (ret)4204				return ret;4205		}4206 4207		if (ffe_ctl->loop == LOOP_NO_EMPTY_SIZE) {4208			if (ffe_ctl->policy != BTRFS_EXTENT_ALLOC_CLUSTERED)4209				return -ENOSPC;4210 4211			/*4212			 * Don't loop again if we already have no empty_size and4213			 * no empty_cluster.4214			 */4215			if (ffe_ctl->empty_size == 0 &&4216			    ffe_ctl->empty_cluster == 0)4217				return -ENOSPC;4218			ffe_ctl->empty_size = 0;4219			ffe_ctl->empty_cluster = 0;4220		}4221		return 1;4222	}4223	return -ENOSPC;4224}4225 4226static bool find_free_extent_check_size_class(struct find_free_extent_ctl *ffe_ctl,4227					      struct btrfs_block_group *bg)4228{4229	if (ffe_ctl->policy == BTRFS_EXTENT_ALLOC_ZONED)4230		return true;4231	if (!btrfs_block_group_should_use_size_class(bg))4232		return true;4233	if (ffe_ctl->loop >= LOOP_WRONG_SIZE_CLASS)4234		return true;4235	if (ffe_ctl->loop >= LOOP_UNSET_SIZE_CLASS &&4236	    bg->size_class == BTRFS_BG_SZ_NONE)4237		return true;4238	return ffe_ctl->size_class == bg->size_class;4239}4240 4241static int prepare_allocation_clustered(struct btrfs_fs_info *fs_info,4242					struct find_free_extent_ctl *ffe_ctl,4243					struct btrfs_space_info *space_info,4244					struct btrfs_key *ins)4245{4246	/*4247	 * If our free space is heavily fragmented we may not be able to make4248	 * big contiguous allocations, so instead of doing the expensive search4249	 * for free space, simply return ENOSPC with our max_extent_size so we4250	 * can go ahead and search for a more manageable chunk.4251	 *4252	 * If our max_extent_size is large enough for our allocation simply4253	 * disable clustering since we will likely not be able to find enough4254	 * space to create a cluster and induce latency trying.4255	 */4256	if (space_info->max_extent_size) {4257		spin_lock(&space_info->lock);4258		if (space_info->max_extent_size &&4259		    ffe_ctl->num_bytes > space_info->max_extent_size) {4260			ins->offset = space_info->max_extent_size;4261			spin_unlock(&space_info->lock);4262			return -ENOSPC;4263		} else if (space_info->max_extent_size) {4264			ffe_ctl->use_cluster = false;4265		}4266		spin_unlock(&space_info->lock);4267	}4268 4269	ffe_ctl->last_ptr = fetch_cluster_info(fs_info, space_info,4270					       &ffe_ctl->empty_cluster);4271	if (ffe_ctl->last_ptr) {4272		struct btrfs_free_cluster *last_ptr = ffe_ctl->last_ptr;4273 4274		spin_lock(&last_ptr->lock);4275		if (last_ptr->block_group)4276			ffe_ctl->hint_byte = last_ptr->window_start;4277		if (last_ptr->fragmented) {4278			/*4279			 * We still set window_start so we can keep track of the4280			 * last place we found an allocation to try and save4281			 * some time.4282			 */4283			ffe_ctl->hint_byte = last_ptr->window_start;4284			ffe_ctl->use_cluster = false;4285		}4286		spin_unlock(&last_ptr->lock);4287	}4288 4289	return 0;4290}4291 4292static int prepare_allocation_zoned(struct btrfs_fs_info *fs_info,4293				    struct find_free_extent_ctl *ffe_ctl)4294{4295	if (ffe_ctl->for_treelog) {4296		spin_lock(&fs_info->treelog_bg_lock);4297		if (fs_info->treelog_bg)4298			ffe_ctl->hint_byte = fs_info->treelog_bg;4299		spin_unlock(&fs_info->treelog_bg_lock);4300	} else if (ffe_ctl->for_data_reloc) {4301		spin_lock(&fs_info->relocation_bg_lock);4302		if (fs_info->data_reloc_bg)4303			ffe_ctl->hint_byte = fs_info->data_reloc_bg;4304		spin_unlock(&fs_info->relocation_bg_lock);4305	} else if (ffe_ctl->flags & BTRFS_BLOCK_GROUP_DATA) {4306		struct btrfs_block_group *block_group;4307 4308		spin_lock(&fs_info->zone_active_bgs_lock);4309		list_for_each_entry(block_group, &fs_info->zone_active_bgs, active_bg_list) {4310			/*4311			 * No lock is OK here because avail is monotinically4312			 * decreasing, and this is just a hint.4313			 */4314			u64 avail = block_group->zone_capacity - block_group->alloc_offset;4315 4316			if (block_group_bits(block_group, ffe_ctl->flags) &&4317			    avail >= ffe_ctl->num_bytes) {4318				ffe_ctl->hint_byte = block_group->start;4319				break;4320			}4321		}4322		spin_unlock(&fs_info->zone_active_bgs_lock);4323	}4324 4325	return 0;4326}4327 4328static int prepare_allocation(struct btrfs_fs_info *fs_info,4329			      struct find_free_extent_ctl *ffe_ctl,4330			      struct btrfs_space_info *space_info,4331			      struct btrfs_key *ins)4332{4333	switch (ffe_ctl->policy) {4334	case BTRFS_EXTENT_ALLOC_CLUSTERED:4335		return prepare_allocation_clustered(fs_info, ffe_ctl,4336						    space_info, ins);4337	case BTRFS_EXTENT_ALLOC_ZONED:4338		return prepare_allocation_zoned(fs_info, ffe_ctl);4339	default:4340		BUG();4341	}4342}4343 4344/*4345 * walks the btree of allocated extents and find a hole of a given size.4346 * The key ins is changed to record the hole:4347 * ins->objectid == start position4348 * ins->flags = BTRFS_EXTENT_ITEM_KEY4349 * ins->offset == the size of the hole.4350 * Any available blocks before search_start are skipped.4351 *4352 * If there is no suitable free space, we will record the max size of4353 * the free space extent currently.4354 *4355 * The overall logic and call chain:4356 *4357 * find_free_extent()4358 * |- Iterate through all block groups4359 * |  |- Get a valid block group4360 * |  |- Try to do clustered allocation in that block group4361 * |  |- Try to do unclustered allocation in that block group4362 * |  |- Check if the result is valid4363 * |  |  |- If valid, then exit4364 * |  |- Jump to next block group4365 * |4366 * |- Push harder to find free extents4367 *    |- If not found, re-iterate all block groups4368 */4369static noinline int find_free_extent(struct btrfs_root *root,4370				     struct btrfs_key *ins,4371				     struct find_free_extent_ctl *ffe_ctl)4372{4373	struct btrfs_fs_info *fs_info = root->fs_info;4374	int ret = 0;4375	int cache_block_group_error = 0;4376	struct btrfs_block_group *block_group = NULL;4377	struct btrfs_space_info *space_info;4378	bool full_search = false;4379 4380	WARN_ON(ffe_ctl->num_bytes < fs_info->sectorsize);4381 4382	ffe_ctl->search_start = 0;4383	/* For clustered allocation */4384	ffe_ctl->empty_cluster = 0;4385	ffe_ctl->last_ptr = NULL;4386	ffe_ctl->use_cluster = true;4387	ffe_ctl->have_caching_bg = false;4388	ffe_ctl->orig_have_caching_bg = false;4389	ffe_ctl->index = btrfs_bg_flags_to_raid_index(ffe_ctl->flags);4390	ffe_ctl->loop = 0;4391	ffe_ctl->retry_uncached = false;4392	ffe_ctl->cached = 0;4393	ffe_ctl->max_extent_size = 0;4394	ffe_ctl->total_free_space = 0;4395	ffe_ctl->found_offset = 0;4396	ffe_ctl->policy = BTRFS_EXTENT_ALLOC_CLUSTERED;4397	ffe_ctl->size_class = btrfs_calc_block_group_size_class(ffe_ctl->num_bytes);4398 4399	if (btrfs_is_zoned(fs_info))4400		ffe_ctl->policy = BTRFS_EXTENT_ALLOC_ZONED;4401 4402	ins->type = BTRFS_EXTENT_ITEM_KEY;4403	ins->objectid = 0;4404	ins->offset = 0;4405 4406	trace_find_free_extent(root, ffe_ctl);4407 4408	space_info = btrfs_find_space_info(fs_info, ffe_ctl->flags);4409	if (!space_info) {4410		btrfs_err(fs_info, "No space info for %llu", ffe_ctl->flags);4411		return -ENOSPC;4412	}4413 4414	ret = prepare_allocation(fs_info, ffe_ctl, space_info, ins);4415	if (ret < 0)4416		return ret;4417 4418	ffe_ctl->search_start = max(ffe_ctl->search_start,4419				    first_logical_byte(fs_info));4420	ffe_ctl->search_start = max(ffe_ctl->search_start, ffe_ctl->hint_byte);4421	if (ffe_ctl->search_start == ffe_ctl->hint_byte) {4422		block_group = btrfs_lookup_block_group(fs_info,4423						       ffe_ctl->search_start);4424		/*4425		 * we don't want to use the block group if it doesn't match our4426		 * allocation bits, or if its not cached.4427		 *4428		 * However if we are re-searching with an ideal block group4429		 * picked out then we don't care that the block group is cached.4430		 */4431		if (block_group && block_group_bits(block_group, ffe_ctl->flags) &&4432		    block_group->cached != BTRFS_CACHE_NO) {4433			down_read(&space_info->groups_sem);4434			if (list_empty(&block_group->list) ||4435			    block_group->ro) {4436				/*4437				 * someone is removing this block group,4438				 * we can't jump into the have_block_group4439				 * target because our list pointers are not4440				 * valid4441				 */4442				btrfs_put_block_group(block_group);4443				up_read(&space_info->groups_sem);4444			} else {4445				ffe_ctl->index = btrfs_bg_flags_to_raid_index(4446							block_group->flags);4447				btrfs_lock_block_group(block_group,4448						       ffe_ctl->delalloc);4449				ffe_ctl->hinted = true;4450				goto have_block_group;4451			}4452		} else if (block_group) {4453			btrfs_put_block_group(block_group);4454		}4455	}4456search:4457	trace_find_free_extent_search_loop(root, ffe_ctl);4458	ffe_ctl->have_caching_bg = false;4459	if (ffe_ctl->index == btrfs_bg_flags_to_raid_index(ffe_ctl->flags) ||4460	    ffe_ctl->index == 0)4461		full_search = true;4462	down_read(&space_info->groups_sem);4463	list_for_each_entry(block_group,4464			    &space_info->block_groups[ffe_ctl->index], list) {4465		struct btrfs_block_group *bg_ret;4466 4467		ffe_ctl->hinted = false;4468		/* If the block group is read-only, we can skip it entirely. */4469		if (unlikely(block_group->ro)) {4470			if (ffe_ctl->for_treelog)4471				btrfs_clear_treelog_bg(block_group);4472			if (ffe_ctl->for_data_reloc)4473				btrfs_clear_data_reloc_bg(block_group);4474			continue;4475		}4476 4477		btrfs_grab_block_group(block_group, ffe_ctl->delalloc);4478		ffe_ctl->search_start = block_group->start;4479 4480		/*4481		 * this can happen if we end up cycling through all the4482		 * raid types, but we want to make sure we only allocate4483		 * for the proper type.4484		 */4485		if (!block_group_bits(block_group, ffe_ctl->flags)) {4486			u64 extra = BTRFS_BLOCK_GROUP_DUP |4487				BTRFS_BLOCK_GROUP_RAID1_MASK |4488				BTRFS_BLOCK_GROUP_RAID56_MASK |4489				BTRFS_BLOCK_GROUP_RAID10;4490 4491			/*4492			 * if they asked for extra copies and this block group4493			 * doesn't provide them, bail.  This does allow us to4494			 * fill raid0 from raid1.4495			 */4496			if ((ffe_ctl->flags & extra) && !(block_group->flags & extra))4497				goto loop;4498 4499			/*4500			 * This block group has different flags than we want.4501			 * It's possible that we have MIXED_GROUP flag but no4502			 * block group is mixed.  Just skip such block group.4503			 */4504			btrfs_release_block_group(block_group, ffe_ctl->delalloc);4505			continue;4506		}4507 4508have_block_group:4509		trace_find_free_extent_have_block_group(root, ffe_ctl, block_group);4510		ffe_ctl->cached = btrfs_block_group_done(block_group);4511		if (unlikely(!ffe_ctl->cached)) {4512			ffe_ctl->have_caching_bg = true;4513			ret = btrfs_cache_block_group(block_group, false);4514 4515			/*4516			 * If we get ENOMEM here or something else we want to4517			 * try other block groups, because it may not be fatal.4518			 * However if we can't find anything else we need to4519			 * save our return here so that we return the actual4520			 * error that caused problems, not ENOSPC.4521			 */4522			if (ret < 0) {4523				if (!cache_block_group_error)4524					cache_block_group_error = ret;4525				ret = 0;4526				goto loop;4527			}4528			ret = 0;4529		}4530 4531		if (unlikely(block_group->cached == BTRFS_CACHE_ERROR)) {4532			if (!cache_block_group_error)4533				cache_block_group_error = -EIO;4534			goto loop;4535		}4536 4537		if (!find_free_extent_check_size_class(ffe_ctl, block_group))4538			goto loop;4539 4540		bg_ret = NULL;4541		ret = do_allocation(block_group, ffe_ctl, &bg_ret);4542		if (ret > 0)4543			goto loop;4544 4545		if (bg_ret && bg_ret != block_group) {4546			btrfs_release_block_group(block_group, ffe_ctl->delalloc);4547			block_group = bg_ret;4548		}4549 4550		/* Checks */4551		ffe_ctl->search_start = round_up(ffe_ctl->found_offset,4552						 fs_info->stripesize);4553 4554		/* move on to the next group */4555		if (ffe_ctl->search_start + ffe_ctl->num_bytes >4556		    block_group->start + block_group->length) {4557			btrfs_add_free_space_unused(block_group,4558					    ffe_ctl->found_offset,4559					    ffe_ctl->num_bytes);4560			goto loop;4561		}4562 4563		if (ffe_ctl->found_offset < ffe_ctl->search_start)4564			btrfs_add_free_space_unused(block_group,4565					ffe_ctl->found_offset,4566					ffe_ctl->search_start - ffe_ctl->found_offset);4567 4568		ret = btrfs_add_reserved_bytes(block_group, ffe_ctl->ram_bytes,4569					       ffe_ctl->num_bytes,4570					       ffe_ctl->delalloc,4571					       ffe_ctl->loop >= LOOP_WRONG_SIZE_CLASS);4572		if (ret == -EAGAIN) {4573			btrfs_add_free_space_unused(block_group,4574					ffe_ctl->found_offset,4575					ffe_ctl->num_bytes);4576			goto loop;4577		}4578		btrfs_inc_block_group_reservations(block_group);4579 4580		/* we are all good, lets return */4581		ins->objectid = ffe_ctl->search_start;4582		ins->offset = ffe_ctl->num_bytes;4583 4584		trace_btrfs_reserve_extent(block_group, ffe_ctl);4585		btrfs_release_block_group(block_group, ffe_ctl->delalloc);4586		break;4587loop:4588		if (!ffe_ctl->cached && ffe_ctl->loop > LOOP_CACHING_NOWAIT &&4589		    !ffe_ctl->retry_uncached) {4590			ffe_ctl->retry_uncached = true;4591			btrfs_wait_block_group_cache_progress(block_group,4592						ffe_ctl->num_bytes +4593						ffe_ctl->empty_cluster +4594						ffe_ctl->empty_size);4595			goto have_block_group;4596		}4597		release_block_group(block_group, ffe_ctl, ffe_ctl->delalloc);4598		cond_resched();4599	}4600	up_read(&space_info->groups_sem);4601 4602	ret = find_free_extent_update_loop(fs_info, ins, ffe_ctl, full_search);4603	if (ret > 0)4604		goto search;4605 4606	if (ret == -ENOSPC && !cache_block_group_error) {4607		/*4608		 * Use ffe_ctl->total_free_space as fallback if we can't find4609		 * any contiguous hole.4610		 */4611		if (!ffe_ctl->max_extent_size)4612			ffe_ctl->max_extent_size = ffe_ctl->total_free_space;4613		spin_lock(&space_info->lock);4614		space_info->max_extent_size = ffe_ctl->max_extent_size;4615		spin_unlock(&space_info->lock);4616		ins->offset = ffe_ctl->max_extent_size;4617	} else if (ret == -ENOSPC) {4618		ret = cache_block_group_error;4619	}4620	return ret;4621}4622 4623/*4624 * Entry point to the extent allocator. Tries to find a hole that is at least4625 * as big as @num_bytes.4626 *4627 * @root           -	The root that will contain this extent4628 *4629 * @ram_bytes      -	The amount of space in ram that @num_bytes take. This4630 *			is used for accounting purposes. This value differs4631 *			from @num_bytes only in the case of compressed extents.4632 *4633 * @num_bytes      -	Number of bytes to allocate on-disk.4634 *4635 * @min_alloc_size -	Indicates the minimum amount of space that the4636 *			allocator should try to satisfy. In some cases4637 *			@num_bytes may be larger than what is required and if4638 *			the filesystem is fragmented then allocation fails.4639 *			However, the presence of @min_alloc_size gives a4640 *			chance to try and satisfy the smaller allocation.4641 *4642 * @empty_size     -	A hint that you plan on doing more COW. This is the4643 *			size in bytes the allocator should try to find free4644 *			next to the block it returns.  This is just a hint and4645 *			may be ignored by the allocator.4646 *4647 * @hint_byte      -	Hint to the allocator to start searching above the byte4648 *			address passed. It might be ignored.4649 *4650 * @ins            -	This key is modified to record the found hole. It will4651 *			have the following values:4652 *			ins->objectid == start position4653 *			ins->flags = BTRFS_EXTENT_ITEM_KEY4654 *			ins->offset == the size of the hole.4655 *4656 * @is_data        -	Boolean flag indicating whether an extent is4657 *			allocated for data (true) or metadata (false)4658 *4659 * @delalloc       -	Boolean flag indicating whether this allocation is for4660 *			delalloc or not. If 'true' data_rwsem of block groups4661 *			is going to be acquired.4662 *4663 *4664 * Returns 0 when an allocation succeeded or < 0 when an error occurred. In4665 * case -ENOSPC is returned then @ins->offset will contain the size of the4666 * largest available hole the allocator managed to find.4667 */4668int btrfs_reserve_extent(struct btrfs_root *root, u64 ram_bytes,4669			 u64 num_bytes, u64 min_alloc_size,4670			 u64 empty_size, u64 hint_byte,4671			 struct btrfs_key *ins, int is_data, int delalloc)4672{4673	struct btrfs_fs_info *fs_info = root->fs_info;4674	struct find_free_extent_ctl ffe_ctl = {};4675	bool final_tried = num_bytes == min_alloc_size;4676	u64 flags;4677	int ret;4678	bool for_treelog = (btrfs_root_id(root) == BTRFS_TREE_LOG_OBJECTID);4679	bool for_data_reloc = (btrfs_is_data_reloc_root(root) && is_data);4680 4681	flags = get_alloc_profile_by_root(root, is_data);4682again:4683	WARN_ON(num_bytes < fs_info->sectorsize);4684 4685	ffe_ctl.ram_bytes = ram_bytes;4686	ffe_ctl.num_bytes = num_bytes;4687	ffe_ctl.min_alloc_size = min_alloc_size;4688	ffe_ctl.empty_size = empty_size;4689	ffe_ctl.flags = flags;4690	ffe_ctl.delalloc = delalloc;4691	ffe_ctl.hint_byte = hint_byte;4692	ffe_ctl.for_treelog = for_treelog;4693	ffe_ctl.for_data_reloc = for_data_reloc;4694 4695	ret = find_free_extent(root, ins, &ffe_ctl);4696	if (!ret && !is_data) {4697		btrfs_dec_block_group_reservations(fs_info, ins->objectid);4698	} else if (ret == -ENOSPC) {4699		if (!final_tried && ins->offset) {4700			num_bytes = min(num_bytes >> 1, ins->offset);4701			num_bytes = round_down(num_bytes,4702					       fs_info->sectorsize);4703			num_bytes = max(num_bytes, min_alloc_size);4704			ram_bytes = num_bytes;4705			if (num_bytes == min_alloc_size)4706				final_tried = true;4707			goto again;4708		} else if (btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {4709			struct btrfs_space_info *sinfo;4710 4711			sinfo = btrfs_find_space_info(fs_info, flags);4712			btrfs_err(fs_info,4713	"allocation failed flags %llu, wanted %llu tree-log %d, relocation: %d",4714				  flags, num_bytes, for_treelog, for_data_reloc);4715			if (sinfo)4716				btrfs_dump_space_info(fs_info, sinfo,4717						      num_bytes, 1);4718		}4719	}4720 4721	return ret;4722}4723 4724int btrfs_free_reserved_extent(struct btrfs_fs_info *fs_info,4725			       u64 start, u64 len, int delalloc)4726{4727	struct btrfs_block_group *cache;4728 4729	cache = btrfs_lookup_block_group(fs_info, start);4730	if (!cache) {4731		btrfs_err(fs_info, "Unable to find block group for %llu",4732			  start);4733		return -ENOSPC;4734	}4735 4736	btrfs_add_free_space(cache, start, len);4737	btrfs_free_reserved_bytes(cache, len, delalloc);4738	trace_btrfs_reserved_extent_free(fs_info, start, len);4739 4740	btrfs_put_block_group(cache);4741	return 0;4742}4743 4744int btrfs_pin_reserved_extent(struct btrfs_trans_handle *trans,4745			      const struct extent_buffer *eb)4746{4747	struct btrfs_block_group *cache;4748	int ret = 0;4749 4750	cache = btrfs_lookup_block_group(trans->fs_info, eb->start);4751	if (!cache) {4752		btrfs_err(trans->fs_info, "unable to find block group for %llu",4753			  eb->start);4754		return -ENOSPC;4755	}4756 4757	ret = pin_down_extent(trans, cache, eb->start, eb->len, 1);4758	btrfs_put_block_group(cache);4759	return ret;4760}4761 4762static int alloc_reserved_extent(struct btrfs_trans_handle *trans, u64 bytenr,4763				 u64 num_bytes)4764{4765	struct btrfs_fs_info *fs_info = trans->fs_info;4766	int ret;4767 4768	ret = remove_from_free_space_tree(trans, bytenr, num_bytes);4769	if (ret)4770		return ret;4771 4772	ret = btrfs_update_block_group(trans, bytenr, num_bytes, true);4773	if (ret) {4774		ASSERT(!ret);4775		btrfs_err(fs_info, "update block group failed for %llu %llu",4776			  bytenr, num_bytes);4777		return ret;4778	}4779 4780	trace_btrfs_reserved_extent_alloc(fs_info, bytenr, num_bytes);4781	return 0;4782}4783 4784static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,4785				      u64 parent, u64 root_objectid,4786				      u64 flags, u64 owner, u64 offset,4787				      struct btrfs_key *ins, int ref_mod, u64 oref_root)4788{4789	struct btrfs_fs_info *fs_info = trans->fs_info;4790	struct btrfs_root *extent_root;4791	int ret;4792	struct btrfs_extent_item *extent_item;4793	struct btrfs_extent_owner_ref *oref;4794	struct btrfs_extent_inline_ref *iref;4795	struct btrfs_path *path;4796	struct extent_buffer *leaf;4797	int type;4798	u32 size;4799	const bool simple_quota = (btrfs_qgroup_mode(fs_info) == BTRFS_QGROUP_MODE_SIMPLE);4800 4801	if (parent > 0)4802		type = BTRFS_SHARED_DATA_REF_KEY;4803	else4804		type = BTRFS_EXTENT_DATA_REF_KEY;4805 4806	size = sizeof(*extent_item);4807	if (simple_quota)4808		size += btrfs_extent_inline_ref_size(BTRFS_EXTENT_OWNER_REF_KEY);4809	size += btrfs_extent_inline_ref_size(type);4810 4811	path = btrfs_alloc_path();4812	if (!path)4813		return -ENOMEM;4814 4815	extent_root = btrfs_extent_root(fs_info, ins->objectid);4816	ret = btrfs_insert_empty_item(trans, extent_root, path, ins, size);4817	if (ret) {4818		btrfs_free_path(path);4819		return ret;4820	}4821 4822	leaf = path->nodes[0];4823	extent_item = btrfs_item_ptr(leaf, path->slots[0],4824				     struct btrfs_extent_item);4825	btrfs_set_extent_refs(leaf, extent_item, ref_mod);4826	btrfs_set_extent_generation(leaf, extent_item, trans->transid);4827	btrfs_set_extent_flags(leaf, extent_item,4828			       flags | BTRFS_EXTENT_FLAG_DATA);4829 4830	iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);4831	if (simple_quota) {4832		btrfs_set_extent_inline_ref_type(leaf, iref, BTRFS_EXTENT_OWNER_REF_KEY);4833		oref = (struct btrfs_extent_owner_ref *)(&iref->offset);4834		btrfs_set_extent_owner_ref_root_id(leaf, oref, oref_root);4835		iref = (struct btrfs_extent_inline_ref *)(oref + 1);4836	}4837	btrfs_set_extent_inline_ref_type(leaf, iref, type);4838 4839	if (parent > 0) {4840		struct btrfs_shared_data_ref *ref;4841		ref = (struct btrfs_shared_data_ref *)(iref + 1);4842		btrfs_set_extent_inline_ref_offset(leaf, iref, parent);4843		btrfs_set_shared_data_ref_count(leaf, ref, ref_mod);4844	} else {4845		struct btrfs_extent_data_ref *ref;4846		ref = (struct btrfs_extent_data_ref *)(&iref->offset);4847		btrfs_set_extent_data_ref_root(leaf, ref, root_objectid);4848		btrfs_set_extent_data_ref_objectid(leaf, ref, owner);4849		btrfs_set_extent_data_ref_offset(leaf, ref, offset);4850		btrfs_set_extent_data_ref_count(leaf, ref, ref_mod);4851	}4852 4853	btrfs_mark_buffer_dirty(trans, path->nodes[0]);4854	btrfs_free_path(path);4855 4856	return alloc_reserved_extent(trans, ins->objectid, ins->offset);4857}4858 4859static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,4860				     struct btrfs_delayed_ref_node *node,4861				     struct btrfs_delayed_extent_op *extent_op)4862{4863	struct btrfs_fs_info *fs_info = trans->fs_info;4864	struct btrfs_root *extent_root;4865	int ret;4866	struct btrfs_extent_item *extent_item;4867	struct btrfs_key extent_key;4868	struct btrfs_tree_block_info *block_info;4869	struct btrfs_extent_inline_ref *iref;4870	struct btrfs_path *path;4871	struct extent_buffer *leaf;4872	u32 size = sizeof(*extent_item) + sizeof(*iref);4873	const u64 flags = (extent_op ? extent_op->flags_to_set : 0);4874	/* The owner of a tree block is the level. */4875	int level = btrfs_delayed_ref_owner(node);4876	bool skinny_metadata = btrfs_fs_incompat(fs_info, SKINNY_METADATA);4877 4878	extent_key.objectid = node->bytenr;4879	if (skinny_metadata) {4880		/* The owner of a tree block is the level. */4881		extent_key.offset = level;4882		extent_key.type = BTRFS_METADATA_ITEM_KEY;4883	} else {4884		extent_key.offset = node->num_bytes;4885		extent_key.type = BTRFS_EXTENT_ITEM_KEY;4886		size += sizeof(*block_info);4887	}4888 4889	path = btrfs_alloc_path();4890	if (!path)4891		return -ENOMEM;4892 4893	extent_root = btrfs_extent_root(fs_info, extent_key.objectid);4894	ret = btrfs_insert_empty_item(trans, extent_root, path, &extent_key,4895				      size);4896	if (ret) {4897		btrfs_free_path(path);4898		return ret;4899	}4900 4901	leaf = path->nodes[0];4902	extent_item = btrfs_item_ptr(leaf, path->slots[0],4903				     struct btrfs_extent_item);4904	btrfs_set_extent_refs(leaf, extent_item, 1);4905	btrfs_set_extent_generation(leaf, extent_item, trans->transid);4906	btrfs_set_extent_flags(leaf, extent_item,4907			       flags | BTRFS_EXTENT_FLAG_TREE_BLOCK);4908 4909	if (skinny_metadata) {4910		iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);4911	} else {4912		block_info = (struct btrfs_tree_block_info *)(extent_item + 1);4913		btrfs_set_tree_block_key(leaf, block_info, &extent_op->key);4914		btrfs_set_tree_block_level(leaf, block_info, level);4915		iref = (struct btrfs_extent_inline_ref *)(block_info + 1);4916	}4917 4918	if (node->type == BTRFS_SHARED_BLOCK_REF_KEY) {4919		btrfs_set_extent_inline_ref_type(leaf, iref,4920						 BTRFS_SHARED_BLOCK_REF_KEY);4921		btrfs_set_extent_inline_ref_offset(leaf, iref, node->parent);4922	} else {4923		btrfs_set_extent_inline_ref_type(leaf, iref,4924						 BTRFS_TREE_BLOCK_REF_KEY);4925		btrfs_set_extent_inline_ref_offset(leaf, iref, node->ref_root);4926	}4927 4928	btrfs_mark_buffer_dirty(trans, leaf);4929	btrfs_free_path(path);4930 4931	return alloc_reserved_extent(trans, node->bytenr, fs_info->nodesize);4932}4933 4934int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,4935				     struct btrfs_root *root, u64 owner,4936				     u64 offset, u64 ram_bytes,4937				     struct btrfs_key *ins)4938{4939	struct btrfs_ref generic_ref = {4940		.action = BTRFS_ADD_DELAYED_EXTENT,4941		.bytenr = ins->objectid,4942		.num_bytes = ins->offset,4943		.owning_root = btrfs_root_id(root),4944		.ref_root = btrfs_root_id(root),4945	};4946 4947	ASSERT(generic_ref.ref_root != BTRFS_TREE_LOG_OBJECTID);4948 4949	if (btrfs_is_data_reloc_root(root) && is_fstree(root->relocation_src_root))4950		generic_ref.owning_root = root->relocation_src_root;4951 4952	btrfs_init_data_ref(&generic_ref, owner, offset, 0, false);4953	btrfs_ref_tree_mod(root->fs_info, &generic_ref);4954 4955	return btrfs_add_delayed_data_ref(trans, &generic_ref, ram_bytes);4956}4957 4958/*4959 * this is used by the tree logging recovery code.  It records that4960 * an extent has been allocated and makes sure to clear the free4961 * space cache bits as well4962 */4963int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,4964				   u64 root_objectid, u64 owner, u64 offset,4965				   struct btrfs_key *ins)4966{4967	struct btrfs_fs_info *fs_info = trans->fs_info;4968	int ret;4969	struct btrfs_block_group *block_group;4970	struct btrfs_space_info *space_info;4971	struct btrfs_squota_delta delta = {4972		.root = root_objectid,4973		.num_bytes = ins->offset,4974		.generation = trans->transid,4975		.is_data = true,4976		.is_inc = true,4977	};4978 4979	/*4980	 * Mixed block groups will exclude before processing the log so we only4981	 * need to do the exclude dance if this fs isn't mixed.4982	 */4983	if (!btrfs_fs_incompat(fs_info, MIXED_GROUPS)) {4984		ret = __exclude_logged_extent(fs_info, ins->objectid,4985					      ins->offset);4986		if (ret)4987			return ret;4988	}4989 4990	block_group = btrfs_lookup_block_group(fs_info, ins->objectid);4991	if (!block_group)4992		return -EINVAL;4993 4994	space_info = block_group->space_info;4995	spin_lock(&space_info->lock);4996	spin_lock(&block_group->lock);4997	space_info->bytes_reserved += ins->offset;4998	block_group->reserved += ins->offset;4999	spin_unlock(&block_group->lock);5000	spin_unlock(&space_info->lock);5001 5002	ret = alloc_reserved_file_extent(trans, 0, root_objectid, 0, owner,5003					 offset, ins, 1, root_objectid);5004	if (ret)5005		btrfs_pin_extent(trans, ins->objectid, ins->offset, 1);5006	ret = btrfs_record_squota_delta(fs_info, &delta);5007	btrfs_put_block_group(block_group);5008	return ret;5009}5010 5011#ifdef CONFIG_BTRFS_DEBUG5012/*5013 * Extra safety check in case the extent tree is corrupted and extent allocator5014 * chooses to use a tree block which is already used and locked.5015 */5016static bool check_eb_lock_owner(const struct extent_buffer *eb)5017{5018	if (eb->lock_owner == current->pid) {5019		btrfs_err_rl(eb->fs_info,5020"tree block %llu owner %llu already locked by pid=%d, extent tree corruption detected",5021			     eb->start, btrfs_header_owner(eb), current->pid);5022		return true;5023	}5024	return false;5025}5026#else5027static bool check_eb_lock_owner(struct extent_buffer *eb)5028{5029	return false;5030}5031#endif5032 5033static struct extent_buffer *5034btrfs_init_new_buffer(struct btrfs_trans_handle *trans, struct btrfs_root *root,5035		      u64 bytenr, int level, u64 owner,5036		      enum btrfs_lock_nesting nest)5037{5038	struct btrfs_fs_info *fs_info = root->fs_info;5039	struct extent_buffer *buf;5040	u64 lockdep_owner = owner;5041 5042	buf = btrfs_find_create_tree_block(fs_info, bytenr, owner, level);5043	if (IS_ERR(buf))5044		return buf;5045 5046	if (check_eb_lock_owner(buf)) {5047		free_extent_buffer(buf);5048		return ERR_PTR(-EUCLEAN);5049	}5050 5051	/*5052	 * The reloc trees are just snapshots, so we need them to appear to be5053	 * just like any other fs tree WRT lockdep.5054	 *5055	 * The exception however is in replace_path() in relocation, where we5056	 * hold the lock on the original fs root and then search for the reloc5057	 * root.  At that point we need to make sure any reloc root buffers are5058	 * set to the BTRFS_TREE_RELOC_OBJECTID lockdep class in order to make5059	 * lockdep happy.5060	 */5061	if (lockdep_owner == BTRFS_TREE_RELOC_OBJECTID &&5062	    !test_bit(BTRFS_ROOT_RESET_LOCKDEP_CLASS, &root->state))5063		lockdep_owner = BTRFS_FS_TREE_OBJECTID;5064 5065	/* btrfs_clear_buffer_dirty() accesses generation field. */5066	btrfs_set_header_generation(buf, trans->transid);5067 5068	/*5069	 * This needs to stay, because we could allocate a freed block from an5070	 * old tree into a new tree, so we need to make sure this new block is5071	 * set to the appropriate level and owner.5072	 */5073	btrfs_set_buffer_lockdep_class(lockdep_owner, buf, level);5074 5075	btrfs_tree_lock_nested(buf, nest);5076	btrfs_clear_buffer_dirty(trans, buf);5077	clear_bit(EXTENT_BUFFER_STALE, &buf->bflags);5078	clear_bit(EXTENT_BUFFER_ZONED_ZEROOUT, &buf->bflags);5079 5080	set_extent_buffer_uptodate(buf);5081 5082	memzero_extent_buffer(buf, 0, sizeof(struct btrfs_header));5083	btrfs_set_header_level(buf, level);5084	btrfs_set_header_bytenr(buf, buf->start);5085	btrfs_set_header_generation(buf, trans->transid);5086	btrfs_set_header_backref_rev(buf, BTRFS_MIXED_BACKREF_REV);5087	btrfs_set_header_owner(buf, owner);5088	write_extent_buffer_fsid(buf, fs_info->fs_devices->metadata_uuid);5089	write_extent_buffer_chunk_tree_uuid(buf, fs_info->chunk_tree_uuid);5090	if (btrfs_root_id(root) == BTRFS_TREE_LOG_OBJECTID) {5091		buf->log_index = root->log_transid % 2;5092		/*5093		 * we allow two log transactions at a time, use different5094		 * EXTENT bit to differentiate dirty pages.5095		 */5096		if (buf->log_index == 0)5097			set_extent_bit(&root->dirty_log_pages, buf->start,5098				       buf->start + buf->len - 1,5099				       EXTENT_DIRTY, NULL);5100		else5101			set_extent_bit(&root->dirty_log_pages, buf->start,5102				       buf->start + buf->len - 1,5103				       EXTENT_NEW, NULL);5104	} else {5105		buf->log_index = -1;5106		set_extent_bit(&trans->transaction->dirty_pages, buf->start,5107			       buf->start + buf->len - 1, EXTENT_DIRTY, NULL);5108	}5109	/* this returns a buffer locked for blocking */5110	return buf;5111}5112 5113/*5114 * finds a free extent and does all the dirty work required for allocation5115 * returns the tree buffer or an ERR_PTR on error.5116 */5117struct extent_buffer *btrfs_alloc_tree_block(struct btrfs_trans_handle *trans,5118					     struct btrfs_root *root,5119					     u64 parent, u64 root_objectid,5120					     const struct btrfs_disk_key *key,5121					     int level, u64 hint,5122					     u64 empty_size,5123					     u64 reloc_src_root,5124					     enum btrfs_lock_nesting nest)5125{5126	struct btrfs_fs_info *fs_info = root->fs_info;5127	struct btrfs_key ins;5128	struct btrfs_block_rsv *block_rsv;5129	struct extent_buffer *buf;5130	u64 flags = 0;5131	int ret;5132	u32 blocksize = fs_info->nodesize;5133	bool skinny_metadata = btrfs_fs_incompat(fs_info, SKINNY_METADATA);5134	u64 owning_root;5135 5136#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS5137	if (btrfs_is_testing(fs_info)) {5138		buf = btrfs_init_new_buffer(trans, root, root->alloc_bytenr,5139					    level, root_objectid, nest);5140		if (!IS_ERR(buf))5141			root->alloc_bytenr += blocksize;5142		return buf;5143	}5144#endif5145 5146	block_rsv = btrfs_use_block_rsv(trans, root, blocksize);5147	if (IS_ERR(block_rsv))5148		return ERR_CAST(block_rsv);5149 5150	ret = btrfs_reserve_extent(root, blocksize, blocksize, blocksize,5151				   empty_size, hint, &ins, 0, 0);5152	if (ret)5153		goto out_unuse;5154 5155	buf = btrfs_init_new_buffer(trans, root, ins.objectid, level,5156				    root_objectid, nest);5157	if (IS_ERR(buf)) {5158		ret = PTR_ERR(buf);5159		goto out_free_reserved;5160	}5161	owning_root = btrfs_header_owner(buf);5162 5163	if (root_objectid == BTRFS_TREE_RELOC_OBJECTID) {5164		if (parent == 0)5165			parent = ins.objectid;5166		flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF;5167		owning_root = reloc_src_root;5168	} else5169		BUG_ON(parent > 0);5170 5171	if (root_objectid != BTRFS_TREE_LOG_OBJECTID) {5172		struct btrfs_delayed_extent_op *extent_op;5173		struct btrfs_ref generic_ref = {5174			.action = BTRFS_ADD_DELAYED_EXTENT,5175			.bytenr = ins.objectid,5176			.num_bytes = ins.offset,5177			.parent = parent,5178			.owning_root = owning_root,5179			.ref_root = root_objectid,5180		};5181 5182		if (!skinny_metadata || flags != 0) {5183			extent_op = btrfs_alloc_delayed_extent_op();5184			if (!extent_op) {5185				ret = -ENOMEM;5186				goto out_free_buf;5187			}5188			if (key)5189				memcpy(&extent_op->key, key, sizeof(extent_op->key));5190			else5191				memset(&extent_op->key, 0, sizeof(extent_op->key));5192			extent_op->flags_to_set = flags;5193			extent_op->update_key = (skinny_metadata ? false : true);5194			extent_op->update_flags = (flags != 0);5195		} else {5196			extent_op = NULL;5197		}5198 5199		btrfs_init_tree_ref(&generic_ref, level, btrfs_root_id(root), false);5200		btrfs_ref_tree_mod(fs_info, &generic_ref);5201		ret = btrfs_add_delayed_tree_ref(trans, &generic_ref, extent_op);5202		if (ret) {5203			btrfs_free_delayed_extent_op(extent_op);5204			goto out_free_buf;5205		}5206	}5207	return buf;5208 5209out_free_buf:5210	btrfs_tree_unlock(buf);5211	free_extent_buffer(buf);5212out_free_reserved:5213	btrfs_free_reserved_extent(fs_info, ins.objectid, ins.offset, 0);5214out_unuse:5215	btrfs_unuse_block_rsv(fs_info, block_rsv, blocksize);5216	return ERR_PTR(ret);5217}5218 5219struct walk_control {5220	u64 refs[BTRFS_MAX_LEVEL];5221	u64 flags[BTRFS_MAX_LEVEL];5222	struct btrfs_key update_progress;5223	struct btrfs_key drop_progress;5224	int drop_level;5225	int stage;5226	int level;5227	int shared_level;5228	int update_ref;5229	int keep_locks;5230	int reada_slot;5231	int reada_count;5232	int restarted;5233	/* Indicate that extent info needs to be looked up when walking the tree. */5234	int lookup_info;5235};5236 5237/*5238 * This is our normal stage.  We are traversing blocks the current snapshot owns5239 * and we are dropping any of our references to any children we are able to, and5240 * then freeing the block once we've processed all of the children.5241 */5242#define DROP_REFERENCE	15243 5244/*5245 * We enter this stage when we have to walk into a child block (meaning we can't5246 * simply drop our reference to it from our current parent node) and there are5247 * more than one reference on it.  If we are the owner of any of the children5248 * blocks from the current parent node then we have to do the FULL_BACKREF dance5249 * on them in order to drop our normal ref and add the shared ref.5250 */5251#define UPDATE_BACKREF	25252 5253/*5254 * Decide if we need to walk down into this node to adjust the references.5255 *5256 * @root:	the root we are currently deleting5257 * @wc:		the walk control for this deletion5258 * @eb:		the parent eb that we're currently visiting5259 * @refs:	the number of refs for wc->level - 15260 * @flags:	the flags for wc->level - 15261 * @slot:	the slot in the eb that we're currently checking5262 *5263 * This is meant to be called when we're evaluating if a node we point to at5264 * wc->level should be read and walked into, or if we can simply delete our5265 * reference to it.  We return true if we should walk into the node, false if we5266 * can skip it.5267 *5268 * We have assertions in here to make sure this is called correctly.  We assume5269 * that sanity checking on the blocks read to this point has been done, so any5270 * corrupted file systems must have been caught before calling this function.5271 */5272static bool visit_node_for_delete(struct btrfs_root *root, struct walk_control *wc,5273				  struct extent_buffer *eb, u64 refs, u64 flags, int slot)5274{5275	struct btrfs_key key;5276	u64 generation;5277	int level = wc->level;5278 5279	ASSERT(level > 0);5280	ASSERT(wc->refs[level - 1] > 0);5281 5282	/*5283	 * The update backref stage we only want to skip if we already have5284	 * FULL_BACKREF set, otherwise we need to read.5285	 */5286	if (wc->stage == UPDATE_BACKREF) {5287		if (level == 1 && flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)5288			return false;5289		return true;5290	}5291 5292	/*5293	 * We're the last ref on this block, we must walk into it and process5294	 * any refs it's pointing at.5295	 */5296	if (wc->refs[level - 1] == 1)5297		return true;5298 5299	/*5300	 * If we're already FULL_BACKREF then we know we can just drop our5301	 * current reference.5302	 */5303	if (level == 1 && flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)5304		return false;5305 5306	/*5307	 * This block is older than our creation generation, we can drop our5308	 * reference to it.5309	 */5310	generation = btrfs_node_ptr_generation(eb, slot);5311	if (!wc->update_ref || generation <= root->root_key.offset)5312		return false;5313 5314	/*5315	 * This block was processed from a previous snapshot deletion run, we5316	 * can skip it.5317	 */5318	btrfs_node_key_to_cpu(eb, &key, slot);5319	if (btrfs_comp_cpu_keys(&key, &wc->update_progress) < 0)5320		return false;5321 5322	/* All other cases we need to wander into the node. */5323	return true;5324}5325 5326static noinline void reada_walk_down(struct btrfs_trans_handle *trans,5327				     struct btrfs_root *root,5328				     struct walk_control *wc,5329				     struct btrfs_path *path)5330{5331	struct btrfs_fs_info *fs_info = root->fs_info;5332	u64 bytenr;5333	u64 generation;5334	u64 refs;5335	u64 flags;5336	u32 nritems;5337	struct extent_buffer *eb;5338	int ret;5339	int slot;5340	int nread = 0;5341 5342	if (path->slots[wc->level] < wc->reada_slot) {5343		wc->reada_count = wc->reada_count * 2 / 3;5344		wc->reada_count = max(wc->reada_count, 2);5345	} else {5346		wc->reada_count = wc->reada_count * 3 / 2;5347		wc->reada_count = min_t(int, wc->reada_count,5348					BTRFS_NODEPTRS_PER_BLOCK(fs_info));5349	}5350 5351	eb = path->nodes[wc->level];5352	nritems = btrfs_header_nritems(eb);5353 5354	for (slot = path->slots[wc->level]; slot < nritems; slot++) {5355		if (nread >= wc->reada_count)5356			break;5357 5358		cond_resched();5359		bytenr = btrfs_node_blockptr(eb, slot);5360		generation = btrfs_node_ptr_generation(eb, slot);5361 5362		if (slot == path->slots[wc->level])5363			goto reada;5364 5365		if (wc->stage == UPDATE_BACKREF &&5366		    generation <= root->root_key.offset)5367			continue;5368 5369		/* We don't lock the tree block, it's OK to be racy here */5370		ret = btrfs_lookup_extent_info(trans, fs_info, bytenr,5371					       wc->level - 1, 1, &refs,5372					       &flags, NULL);5373		/* We don't care about errors in readahead. */5374		if (ret < 0)5375			continue;5376 5377		/*5378		 * This could be racey, it's conceivable that we raced and end5379		 * up with a bogus refs count, if that's the case just skip, if5380		 * we are actually corrupt we will notice when we look up5381		 * everything again with our locks.5382		 */5383		if (refs == 0)5384			continue;5385 5386		/* If we don't need to visit this node don't reada. */5387		if (!visit_node_for_delete(root, wc, eb, refs, flags, slot))5388			continue;5389reada:5390		btrfs_readahead_node_child(eb, slot);5391		nread++;5392	}5393	wc->reada_slot = slot;5394}5395 5396/*5397 * helper to process tree block while walking down the tree.5398 *5399 * when wc->stage == UPDATE_BACKREF, this function updates5400 * back refs for pointers in the block.5401 *5402 * NOTE: return value 1 means we should stop walking down.5403 */5404static noinline int walk_down_proc(struct btrfs_trans_handle *trans,5405				   struct btrfs_root *root,5406				   struct btrfs_path *path,5407				   struct walk_control *wc)5408{5409	struct btrfs_fs_info *fs_info = root->fs_info;5410	int level = wc->level;5411	struct extent_buffer *eb = path->nodes[level];5412	u64 flag = BTRFS_BLOCK_FLAG_FULL_BACKREF;5413	int ret;5414 5415	if (wc->stage == UPDATE_BACKREF && btrfs_header_owner(eb) != btrfs_root_id(root))5416		return 1;5417 5418	/*5419	 * when reference count of tree block is 1, it won't increase5420	 * again. once full backref flag is set, we never clear it.5421	 */5422	if (wc->lookup_info &&5423	    ((wc->stage == DROP_REFERENCE && wc->refs[level] != 1) ||5424	     (wc->stage == UPDATE_BACKREF && !(wc->flags[level] & flag)))) {5425		ASSERT(path->locks[level]);5426		ret = btrfs_lookup_extent_info(trans, fs_info,5427					       eb->start, level, 1,5428					       &wc->refs[level],5429					       &wc->flags[level],5430					       NULL);5431		if (ret)5432			return ret;5433		if (unlikely(wc->refs[level] == 0)) {5434			btrfs_err(fs_info, "bytenr %llu has 0 references, expect > 0",5435				  eb->start);5436			return -EUCLEAN;5437		}5438	}5439 5440	if (wc->stage == DROP_REFERENCE) {5441		if (wc->refs[level] > 1)5442			return 1;5443 5444		if (path->locks[level] && !wc->keep_locks) {5445			btrfs_tree_unlock_rw(eb, path->locks[level]);5446			path->locks[level] = 0;5447		}5448		return 0;5449	}5450 5451	/* wc->stage == UPDATE_BACKREF */5452	if (!(wc->flags[level] & flag)) {5453		ASSERT(path->locks[level]);5454		ret = btrfs_inc_ref(trans, root, eb, 1);5455		if (ret) {5456			btrfs_abort_transaction(trans, ret);5457			return ret;5458		}5459		ret = btrfs_dec_ref(trans, root, eb, 0);5460		if (ret) {5461			btrfs_abort_transaction(trans, ret);5462			return ret;5463		}5464		ret = btrfs_set_disk_extent_flags(trans, eb, flag);5465		if (ret) {5466			btrfs_abort_transaction(trans, ret);5467			return ret;5468		}5469		wc->flags[level] |= flag;5470	}5471 5472	/*5473	 * the block is shared by multiple trees, so it's not good to5474	 * keep the tree lock5475	 */5476	if (path->locks[level] && level > 0) {5477		btrfs_tree_unlock_rw(eb, path->locks[level]);5478		path->locks[level] = 0;5479	}5480	return 0;5481}5482 5483/*5484 * This is used to verify a ref exists for this root to deal with a bug where we5485 * would have a drop_progress key that hadn't been updated properly.5486 */5487static int check_ref_exists(struct btrfs_trans_handle *trans,5488			    struct btrfs_root *root, u64 bytenr, u64 parent,5489			    int level)5490{5491	struct btrfs_delayed_ref_root *delayed_refs;5492	struct btrfs_delayed_ref_head *head;5493	struct btrfs_path *path;5494	struct btrfs_extent_inline_ref *iref;5495	int ret;5496	bool exists = false;5497 5498	path = btrfs_alloc_path();5499	if (!path)5500		return -ENOMEM;5501again:5502	ret = lookup_extent_backref(trans, path, &iref, bytenr,5503				    root->fs_info->nodesize, parent,5504				    btrfs_root_id(root), level, 0);5505	if (ret != -ENOENT) {5506		/*5507		 * If we get 0 then we found our reference, return 1, else5508		 * return the error if it's not -ENOENT;5509		 */5510		btrfs_free_path(path);5511		return (ret < 0 ) ? ret : 1;5512	}5513 5514	/*5515	 * We could have a delayed ref with this reference, so look it up while5516	 * we're holding the path open to make sure we don't race with the5517	 * delayed ref running.5518	 */5519	delayed_refs = &trans->transaction->delayed_refs;5520	spin_lock(&delayed_refs->lock);5521	head = btrfs_find_delayed_ref_head(delayed_refs, bytenr);5522	if (!head)5523		goto out;5524	if (!mutex_trylock(&head->mutex)) {5525		/*5526		 * We're contended, means that the delayed ref is running, get a5527		 * reference and wait for the ref head to be complete and then5528		 * try again.5529		 */5530		refcount_inc(&head->refs);5531		spin_unlock(&delayed_refs->lock);5532 5533		btrfs_release_path(path);5534 5535		mutex_lock(&head->mutex);5536		mutex_unlock(&head->mutex);5537		btrfs_put_delayed_ref_head(head);5538		goto again;5539	}5540 5541	exists = btrfs_find_delayed_tree_ref(head, root->root_key.objectid, parent);5542	mutex_unlock(&head->mutex);5543out:5544	spin_unlock(&delayed_refs->lock);5545	btrfs_free_path(path);5546	return exists ? 1 : 0;5547}5548 5549/*5550 * We may not have an uptodate block, so if we are going to walk down into this5551 * block we need to drop the lock, read it off of the disk, re-lock it and5552 * return to continue dropping the snapshot.5553 */5554static int check_next_block_uptodate(struct btrfs_trans_handle *trans,5555				     struct btrfs_root *root,5556				     struct btrfs_path *path,5557				     struct walk_control *wc,5558				     struct extent_buffer *next)5559{5560	struct btrfs_tree_parent_check check = { 0 };5561	u64 generation;5562	int level = wc->level;5563	int ret;5564 5565	btrfs_assert_tree_write_locked(next);5566 5567	generation = btrfs_node_ptr_generation(path->nodes[level], path->slots[level]);5568 5569	if (btrfs_buffer_uptodate(next, generation, 0))5570		return 0;5571 5572	check.level = level - 1;5573	check.transid = generation;5574	check.owner_root = btrfs_root_id(root);5575	check.has_first_key = true;5576	btrfs_node_key_to_cpu(path->nodes[level], &check.first_key, path->slots[level]);5577 5578	btrfs_tree_unlock(next);5579	if (level == 1)5580		reada_walk_down(trans, root, wc, path);5581	ret = btrfs_read_extent_buffer(next, &check);5582	if (ret) {5583		free_extent_buffer(next);5584		return ret;5585	}5586	btrfs_tree_lock(next);5587	wc->lookup_info = 1;5588	return 0;5589}5590 5591/*5592 * If we determine that we don't have to visit wc->level - 1 then we need to5593 * determine if we can drop our reference.5594 *5595 * If we are UPDATE_BACKREF then we will not, we need to update our backrefs.5596 *5597 * If we are DROP_REFERENCE this will figure out if we need to drop our current5598 * reference, skipping it if we dropped it from a previous incompleted drop, or5599 * dropping it if we still have a reference to it.5600 */5601static int maybe_drop_reference(struct btrfs_trans_handle *trans, struct btrfs_root *root,5602				struct btrfs_path *path, struct walk_control *wc,5603				struct extent_buffer *next, u64 owner_root)5604{5605	struct btrfs_ref ref = {5606		.action = BTRFS_DROP_DELAYED_REF,5607		.bytenr = next->start,5608		.num_bytes = root->fs_info->nodesize,5609		.owning_root = owner_root,5610		.ref_root = btrfs_root_id(root),5611	};5612	int level = wc->level;5613	int ret;5614 5615	/* We are UPDATE_BACKREF, we're not dropping anything. */5616	if (wc->stage == UPDATE_BACKREF)5617		return 0;5618 5619	if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF) {5620		ref.parent = path->nodes[level]->start;5621	} else {5622		ASSERT(btrfs_root_id(root) == btrfs_header_owner(path->nodes[level]));5623		if (btrfs_root_id(root) != btrfs_header_owner(path->nodes[level])) {5624			btrfs_err(root->fs_info, "mismatched block owner");5625			return -EIO;5626		}5627	}5628 5629	/*5630	 * If we had a drop_progress we need to verify the refs are set as5631	 * expected.  If we find our ref then we know that from here on out5632	 * everything should be correct, and we can clear the5633	 * ->restarted flag.5634	 */5635	if (wc->restarted) {5636		ret = check_ref_exists(trans, root, next->start, ref.parent,5637				       level - 1);5638		if (ret <= 0)5639			return ret;5640		ret = 0;5641		wc->restarted = 0;5642	}5643 5644	/*5645	 * Reloc tree doesn't contribute to qgroup numbers, and we have already5646	 * accounted them at merge time (replace_path), thus we could skip5647	 * expensive subtree trace here.5648	 */5649	if (btrfs_root_id(root) != BTRFS_TREE_RELOC_OBJECTID &&5650	    wc->refs[level - 1] > 1) {5651		u64 generation = btrfs_node_ptr_generation(path->nodes[level],5652							   path->slots[level]);5653 5654		ret = btrfs_qgroup_trace_subtree(trans, next, generation, level - 1);5655		if (ret) {5656			btrfs_err_rl(root->fs_info,5657"error %d accounting shared subtree, quota is out of sync, rescan required",5658				     ret);5659		}5660	}5661 5662	/*5663	 * We need to update the next key in our walk control so we can update5664	 * the drop_progress key accordingly.  We don't care if find_next_key5665	 * doesn't find a key because that means we're at the end and are going5666	 * to clean up now.5667	 */5668	wc->drop_level = level;5669	find_next_key(path, level, &wc->drop_progress);5670 5671	btrfs_init_tree_ref(&ref, level - 1, 0, false);5672	return btrfs_free_extent(trans, &ref);5673}5674 5675/*5676 * helper to process tree block pointer.5677 *5678 * when wc->stage == DROP_REFERENCE, this function checks5679 * reference count of the block pointed to. if the block5680 * is shared and we need update back refs for the subtree5681 * rooted at the block, this function changes wc->stage to5682 * UPDATE_BACKREF. if the block is shared and there is no5683 * need to update back, this function drops the reference5684 * to the block.5685 *5686 * NOTE: return value 1 means we should stop walking down.5687 */5688static noinline int do_walk_down(struct btrfs_trans_handle *trans,5689				 struct btrfs_root *root,5690				 struct btrfs_path *path,5691				 struct walk_control *wc)5692{5693	struct btrfs_fs_info *fs_info = root->fs_info;5694	u64 bytenr;5695	u64 generation;5696	u64 owner_root = 0;5697	struct extent_buffer *next;5698	int level = wc->level;5699	int ret = 0;5700 5701	generation = btrfs_node_ptr_generation(path->nodes[level],5702					       path->slots[level]);5703	/*5704	 * if the lower level block was created before the snapshot5705	 * was created, we know there is no need to update back refs5706	 * for the subtree5707	 */5708	if (wc->stage == UPDATE_BACKREF &&5709	    generation <= root->root_key.offset) {5710		wc->lookup_info = 1;5711		return 1;5712	}5713 5714	bytenr = btrfs_node_blockptr(path->nodes[level], path->slots[level]);5715 5716	next = btrfs_find_create_tree_block(fs_info, bytenr, btrfs_root_id(root),5717					    level - 1);5718	if (IS_ERR(next))5719		return PTR_ERR(next);5720 5721	btrfs_tree_lock(next);5722 5723	ret = btrfs_lookup_extent_info(trans, fs_info, bytenr, level - 1, 1,5724				       &wc->refs[level - 1],5725				       &wc->flags[level - 1],5726				       &owner_root);5727	if (ret < 0)5728		goto out_unlock;5729 5730	if (unlikely(wc->refs[level - 1] == 0)) {5731		btrfs_err(fs_info, "bytenr %llu has 0 references, expect > 0",5732			  bytenr);5733		ret = -EUCLEAN;5734		goto out_unlock;5735	}5736	wc->lookup_info = 0;5737 5738	/* If we don't have to walk into this node skip it. */5739	if (!visit_node_for_delete(root, wc, path->nodes[level],5740				   wc->refs[level - 1], wc->flags[level - 1],5741				   path->slots[level]))5742		goto skip;5743 5744	/*5745	 * We have to walk down into this node, and if we're currently at the5746	 * DROP_REFERNCE stage and this block is shared then we need to switch5747	 * to the UPDATE_BACKREF stage in order to convert to FULL_BACKREF.5748	 */5749	if (wc->stage == DROP_REFERENCE && wc->refs[level - 1] > 1) {5750		wc->stage = UPDATE_BACKREF;5751		wc->shared_level = level - 1;5752	}5753 5754	ret = check_next_block_uptodate(trans, root, path, wc, next);5755	if (ret)5756		return ret;5757 5758	level--;5759	ASSERT(level == btrfs_header_level(next));5760	if (level != btrfs_header_level(next)) {5761		btrfs_err(root->fs_info, "mismatched level");5762		ret = -EIO;5763		goto out_unlock;5764	}5765	path->nodes[level] = next;5766	path->slots[level] = 0;5767	path->locks[level] = BTRFS_WRITE_LOCK;5768	wc->level = level;5769	if (wc->level == 1)5770		wc->reada_slot = 0;5771	return 0;5772skip:5773	ret = maybe_drop_reference(trans, root, path, wc, next, owner_root);5774	if (ret)5775		goto out_unlock;5776	wc->refs[level - 1] = 0;5777	wc->flags[level - 1] = 0;5778	wc->lookup_info = 1;5779	ret = 1;5780 5781out_unlock:5782	btrfs_tree_unlock(next);5783	free_extent_buffer(next);5784 5785	return ret;5786}5787 5788/*5789 * helper to process tree block while walking up the tree.5790 *5791 * when wc->stage == DROP_REFERENCE, this function drops5792 * reference count on the block.5793 *5794 * when wc->stage == UPDATE_BACKREF, this function changes5795 * wc->stage back to DROP_REFERENCE if we changed wc->stage5796 * to UPDATE_BACKREF previously while processing the block.5797 *5798 * NOTE: return value 1 means we should stop walking up.5799 */5800static noinline int walk_up_proc(struct btrfs_trans_handle *trans,5801				 struct btrfs_root *root,5802				 struct btrfs_path *path,5803				 struct walk_control *wc)5804{5805	struct btrfs_fs_info *fs_info = root->fs_info;5806	int ret = 0;5807	int level = wc->level;5808	struct extent_buffer *eb = path->nodes[level];5809	u64 parent = 0;5810 5811	if (wc->stage == UPDATE_BACKREF) {5812		ASSERT(wc->shared_level >= level);5813		if (level < wc->shared_level)5814			goto out;5815 5816		ret = find_next_key(path, level + 1, &wc->update_progress);5817		if (ret > 0)5818			wc->update_ref = 0;5819 5820		wc->stage = DROP_REFERENCE;5821		wc->shared_level = -1;5822		path->slots[level] = 0;5823 5824		/*5825		 * check reference count again if the block isn't locked.5826		 * we should start walking down the tree again if reference5827		 * count is one.5828		 */5829		if (!path->locks[level]) {5830			ASSERT(level > 0);5831			btrfs_tree_lock(eb);5832			path->locks[level] = BTRFS_WRITE_LOCK;5833 5834			ret = btrfs_lookup_extent_info(trans, fs_info,5835						       eb->start, level, 1,5836						       &wc->refs[level],5837						       &wc->flags[level],5838						       NULL);5839			if (ret < 0) {5840				btrfs_tree_unlock_rw(eb, path->locks[level]);5841				path->locks[level] = 0;5842				return ret;5843			}5844			if (unlikely(wc->refs[level] == 0)) {5845				btrfs_tree_unlock_rw(eb, path->locks[level]);5846				btrfs_err(fs_info, "bytenr %llu has 0 references, expect > 0",5847					  eb->start);5848				return -EUCLEAN;5849			}5850			if (wc->refs[level] == 1) {5851				btrfs_tree_unlock_rw(eb, path->locks[level]);5852				path->locks[level] = 0;5853				return 1;5854			}5855		}5856	}5857 5858	/* wc->stage == DROP_REFERENCE */5859	ASSERT(path->locks[level] || wc->refs[level] == 1);5860 5861	if (wc->refs[level] == 1) {5862		if (level == 0) {5863			if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)5864				ret = btrfs_dec_ref(trans, root, eb, 1);5865			else5866				ret = btrfs_dec_ref(trans, root, eb, 0);5867			if (ret) {5868				btrfs_abort_transaction(trans, ret);5869				return ret;5870			}5871			if (is_fstree(btrfs_root_id(root))) {5872				ret = btrfs_qgroup_trace_leaf_items(trans, eb);5873				if (ret) {5874					btrfs_err_rl(fs_info,5875	"error %d accounting leaf items, quota is out of sync, rescan required",5876					     ret);5877				}5878			}5879		}5880		/* Make block locked assertion in btrfs_clear_buffer_dirty happy. */5881		if (!path->locks[level]) {5882			btrfs_tree_lock(eb);5883			path->locks[level] = BTRFS_WRITE_LOCK;5884		}5885		btrfs_clear_buffer_dirty(trans, eb);5886	}5887 5888	if (eb == root->node) {5889		if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)5890			parent = eb->start;5891		else if (btrfs_root_id(root) != btrfs_header_owner(eb))5892			goto owner_mismatch;5893	} else {5894		if (wc->flags[level + 1] & BTRFS_BLOCK_FLAG_FULL_BACKREF)5895			parent = path->nodes[level + 1]->start;5896		else if (btrfs_root_id(root) !=5897			 btrfs_header_owner(path->nodes[level + 1]))5898			goto owner_mismatch;5899	}5900 5901	ret = btrfs_free_tree_block(trans, btrfs_root_id(root), eb, parent,5902				    wc->refs[level] == 1);5903	if (ret < 0)5904		btrfs_abort_transaction(trans, ret);5905out:5906	wc->refs[level] = 0;5907	wc->flags[level] = 0;5908	return ret;5909 5910owner_mismatch:5911	btrfs_err_rl(fs_info, "unexpected tree owner, have %llu expect %llu",5912		     btrfs_header_owner(eb), btrfs_root_id(root));5913	return -EUCLEAN;5914}5915 5916/*5917 * walk_down_tree consists of two steps.5918 *5919 * walk_down_proc().  Look up the reference count and reference of our current5920 * wc->level.  At this point path->nodes[wc->level] should be populated and5921 * uptodate, and in most cases should already be locked.  If we are in5922 * DROP_REFERENCE and our refcount is > 1 then we've entered a shared node and5923 * we can walk back up the tree.  If we are UPDATE_BACKREF we have to set5924 * FULL_BACKREF on this node if it's not already set, and then do the5925 * FULL_BACKREF conversion dance, which is to drop the root reference and add5926 * the shared reference to all of this nodes children.5927 *5928 * do_walk_down().  This is where we actually start iterating on the children of5929 * our current path->nodes[wc->level].  For DROP_REFERENCE that means dropping5930 * our reference to the children that return false from visit_node_for_delete(),5931 * which has various conditions where we know we can just drop our reference5932 * without visiting the node.  For UPDATE_BACKREF we will skip any children that5933 * visit_node_for_delete() returns false for, only walking down when necessary.5934 * The bulk of the work for UPDATE_BACKREF occurs in the walk_up_tree() part of5935 * snapshot deletion.5936 */5937static noinline int walk_down_tree(struct btrfs_trans_handle *trans,5938				   struct btrfs_root *root,5939				   struct btrfs_path *path,5940				   struct walk_control *wc)5941{5942	int level = wc->level;5943	int ret = 0;5944 5945	wc->lookup_info = 1;5946	while (level >= 0) {5947		ret = walk_down_proc(trans, root, path, wc);5948		if (ret)5949			break;5950 5951		if (level == 0)5952			break;5953 5954		if (path->slots[level] >=5955		    btrfs_header_nritems(path->nodes[level]))5956			break;5957 5958		ret = do_walk_down(trans, root, path, wc);5959		if (ret > 0) {5960			path->slots[level]++;5961			continue;5962		} else if (ret < 0)5963			break;5964		level = wc->level;5965	}5966	return (ret == 1) ? 0 : ret;5967}5968 5969/*5970 * walk_up_tree() is responsible for making sure we visit every slot on our5971 * current node, and if we're at the end of that node then we call5972 * walk_up_proc() on our current node which will do one of a few things based on5973 * our stage.5974 *5975 * UPDATE_BACKREF.  If we wc->level is currently less than our wc->shared_level5976 * then we need to walk back up the tree, and then going back down into the5977 * other slots via walk_down_tree to update any other children from our original5978 * wc->shared_level.  Once we're at or above our wc->shared_level we can switch5979 * back to DROP_REFERENCE, lookup the current nodes refs and flags, and carry on.5980 *5981 * DROP_REFERENCE. If our refs == 1 then we're going to free this tree block.5982 * If we're level 0 then we need to btrfs_dec_ref() on all of the data extents5983 * in our current leaf.  After that we call btrfs_free_tree_block() on the5984 * current node and walk up to the next node to walk down the next slot.5985 */5986static noinline int walk_up_tree(struct btrfs_trans_handle *trans,5987				 struct btrfs_root *root,5988				 struct btrfs_path *path,5989				 struct walk_control *wc, int max_level)5990{5991	int level = wc->level;5992	int ret;5993 5994	path->slots[level] = btrfs_header_nritems(path->nodes[level]);5995	while (level < max_level && path->nodes[level]) {5996		wc->level = level;5997		if (path->slots[level] + 1 <5998		    btrfs_header_nritems(path->nodes[level])) {5999			path->slots[level]++;6000			return 0;6001		} else {6002			ret = walk_up_proc(trans, root, path, wc);6003			if (ret > 0)6004				return 0;6005			if (ret < 0)6006				return ret;6007 6008			if (path->locks[level]) {6009				btrfs_tree_unlock_rw(path->nodes[level],6010						     path->locks[level]);6011				path->locks[level] = 0;6012			}6013			free_extent_buffer(path->nodes[level]);6014			path->nodes[level] = NULL;6015			level++;6016		}6017	}6018	return 1;6019}6020 6021/*6022 * drop a subvolume tree.6023 *6024 * this function traverses the tree freeing any blocks that only6025 * referenced by the tree.6026 *6027 * when a shared tree block is found. this function decreases its6028 * reference count by one. if update_ref is true, this function6029 * also make sure backrefs for the shared block and all lower level6030 * blocks are properly updated.6031 *6032 * If called with for_reloc == 0, may exit early with -EAGAIN6033 */6034int btrfs_drop_snapshot(struct btrfs_root *root, int update_ref, int for_reloc)6035{6036	const bool is_reloc_root = (btrfs_root_id(root) == BTRFS_TREE_RELOC_OBJECTID);6037	struct btrfs_fs_info *fs_info = root->fs_info;6038	struct btrfs_path *path;6039	struct btrfs_trans_handle *trans;6040	struct btrfs_root *tree_root = fs_info->tree_root;6041	struct btrfs_root_item *root_item = &root->root_item;6042	struct walk_control *wc;6043	struct btrfs_key key;6044	const u64 rootid = btrfs_root_id(root);6045	int ret = 0;6046	int level;6047	bool root_dropped = false;6048	bool unfinished_drop = false;6049 6050	btrfs_debug(fs_info, "Drop subvolume %llu", btrfs_root_id(root));6051 6052	path = btrfs_alloc_path();6053	if (!path) {6054		ret = -ENOMEM;6055		goto out;6056	}6057 6058	wc = kzalloc(sizeof(*wc), GFP_NOFS);6059	if (!wc) {6060		btrfs_free_path(path);6061		ret = -ENOMEM;6062		goto out;6063	}6064 6065	/*6066	 * Use join to avoid potential EINTR from transaction start. See6067	 * wait_reserve_ticket and the whole reservation callchain.6068	 */6069	if (for_reloc)6070		trans = btrfs_join_transaction(tree_root);6071	else6072		trans = btrfs_start_transaction(tree_root, 0);6073	if (IS_ERR(trans)) {6074		ret = PTR_ERR(trans);6075		goto out_free;6076	}6077 6078	ret = btrfs_run_delayed_items(trans);6079	if (ret)6080		goto out_end_trans;6081 6082	/*6083	 * This will help us catch people modifying the fs tree while we're6084	 * dropping it.  It is unsafe to mess with the fs tree while it's being6085	 * dropped as we unlock the root node and parent nodes as we walk down6086	 * the tree, assuming nothing will change.  If something does change6087	 * then we'll have stale information and drop references to blocks we've6088	 * already dropped.6089	 */6090	set_bit(BTRFS_ROOT_DELETING, &root->state);6091	unfinished_drop = test_bit(BTRFS_ROOT_UNFINISHED_DROP, &root->state);6092 6093	if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {6094		level = btrfs_header_level(root->node);6095		path->nodes[level] = btrfs_lock_root_node(root);6096		path->slots[level] = 0;6097		path->locks[level] = BTRFS_WRITE_LOCK;6098		memset(&wc->update_progress, 0,6099		       sizeof(wc->update_progress));6100	} else {6101		btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);6102		memcpy(&wc->update_progress, &key,6103		       sizeof(wc->update_progress));6104 6105		level = btrfs_root_drop_level(root_item);6106		BUG_ON(level == 0);6107		path->lowest_level = level;6108		ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);6109		path->lowest_level = 0;6110		if (ret < 0)6111			goto out_end_trans;6112 6113		WARN_ON(ret > 0);6114		ret = 0;6115 6116		/*6117		 * unlock our path, this is safe because only this6118		 * function is allowed to delete this snapshot6119		 */6120		btrfs_unlock_up_safe(path, 0);6121 6122		level = btrfs_header_level(root->node);6123		while (1) {6124			btrfs_tree_lock(path->nodes[level]);6125			path->locks[level] = BTRFS_WRITE_LOCK;6126 6127			/*6128			 * btrfs_lookup_extent_info() returns 0 for success,6129			 * or < 0 for error.6130			 */6131			ret = btrfs_lookup_extent_info(trans, fs_info,6132						path->nodes[level]->start,6133						level, 1, &wc->refs[level],6134						&wc->flags[level], NULL);6135			if (ret < 0)6136				goto out_end_trans;6137 6138			BUG_ON(wc->refs[level] == 0);6139 6140			if (level == btrfs_root_drop_level(root_item))6141				break;6142 6143			btrfs_tree_unlock(path->nodes[level]);6144			path->locks[level] = 0;6145			WARN_ON(wc->refs[level] != 1);6146			level--;6147		}6148	}6149 6150	wc->restarted = test_bit(BTRFS_ROOT_DEAD_TREE, &root->state);6151	wc->level = level;6152	wc->shared_level = -1;6153	wc->stage = DROP_REFERENCE;6154	wc->update_ref = update_ref;6155	wc->keep_locks = 0;6156	wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(fs_info);6157 6158	while (1) {6159 6160		ret = walk_down_tree(trans, root, path, wc);6161		if (ret < 0) {6162			btrfs_abort_transaction(trans, ret);6163			break;6164		}6165 6166		ret = walk_up_tree(trans, root, path, wc, BTRFS_MAX_LEVEL);6167		if (ret < 0) {6168			btrfs_abort_transaction(trans, ret);6169			break;6170		}6171 6172		if (ret > 0) {6173			BUG_ON(wc->stage != DROP_REFERENCE);6174			ret = 0;6175			break;6176		}6177 6178		if (wc->stage == DROP_REFERENCE) {6179			wc->drop_level = wc->level;6180			btrfs_node_key_to_cpu(path->nodes[wc->drop_level],6181					      &wc->drop_progress,6182					      path->slots[wc->drop_level]);6183		}6184		btrfs_cpu_key_to_disk(&root_item->drop_progress,6185				      &wc->drop_progress);6186		btrfs_set_root_drop_level(root_item, wc->drop_level);6187 6188		BUG_ON(wc->level == 0);6189		if (btrfs_should_end_transaction(trans) ||6190		    (!for_reloc && btrfs_need_cleaner_sleep(fs_info))) {6191			ret = btrfs_update_root(trans, tree_root,6192						&root->root_key,6193						root_item);6194			if (ret) {6195				btrfs_abort_transaction(trans, ret);6196				goto out_end_trans;6197			}6198 6199			if (!is_reloc_root)6200				btrfs_set_last_root_drop_gen(fs_info, trans->transid);6201 6202			btrfs_end_transaction_throttle(trans);6203			if (!for_reloc && btrfs_need_cleaner_sleep(fs_info)) {6204				btrfs_debug(fs_info,6205					    "drop snapshot early exit");6206				ret = -EAGAIN;6207				goto out_free;6208			}6209 6210		       /*6211			* Use join to avoid potential EINTR from transaction6212			* start. See wait_reserve_ticket and the whole6213			* reservation callchain.6214			*/6215			if (for_reloc)6216				trans = btrfs_join_transaction(tree_root);6217			else6218				trans = btrfs_start_transaction(tree_root, 0);6219			if (IS_ERR(trans)) {6220				ret = PTR_ERR(trans);6221				goto out_free;6222			}6223		}6224	}6225	btrfs_release_path(path);6226	if (ret)6227		goto out_end_trans;6228 6229	ret = btrfs_del_root(trans, &root->root_key);6230	if (ret) {6231		btrfs_abort_transaction(trans, ret);6232		goto out_end_trans;6233	}6234 6235	if (!is_reloc_root) {6236		ret = btrfs_find_root(tree_root, &root->root_key, path,6237				      NULL, NULL);6238		if (ret < 0) {6239			btrfs_abort_transaction(trans, ret);6240			goto out_end_trans;6241		} else if (ret > 0) {6242			ret = 0;6243			/*6244			 * If we fail to delete the orphan item this time6245			 * around, it'll get picked up the next time.6246			 *6247			 * The most common failure here is just -ENOENT.6248			 */6249			btrfs_del_orphan_item(trans, tree_root, btrfs_root_id(root));6250		}6251	}6252 6253	/*6254	 * This subvolume is going to be completely dropped, and won't be6255	 * recorded as dirty roots, thus pertrans meta rsv will not be freed at6256	 * commit transaction time.  So free it here manually.6257	 */6258	btrfs_qgroup_convert_reserved_meta(root, INT_MAX);6259	btrfs_qgroup_free_meta_all_pertrans(root);6260 6261	if (test_bit(BTRFS_ROOT_IN_RADIX, &root->state))6262		btrfs_add_dropped_root(trans, root);6263	else6264		btrfs_put_root(root);6265	root_dropped = true;6266out_end_trans:6267	if (!is_reloc_root)6268		btrfs_set_last_root_drop_gen(fs_info, trans->transid);6269 6270	btrfs_end_transaction_throttle(trans);6271out_free:6272	kfree(wc);6273	btrfs_free_path(path);6274out:6275	if (!ret && root_dropped) {6276		ret = btrfs_qgroup_cleanup_dropped_subvolume(fs_info, rootid);6277		if (ret < 0)6278			btrfs_warn_rl(fs_info,6279				      "failed to cleanup qgroup 0/%llu: %d",6280				      rootid, ret);6281		ret = 0;6282	}6283	/*6284	 * We were an unfinished drop root, check to see if there are any6285	 * pending, and if not clear and wake up any waiters.6286	 */6287	if (!ret && unfinished_drop)6288		btrfs_maybe_wake_unfinished_drop(fs_info);6289 6290	/*6291	 * So if we need to stop dropping the snapshot for whatever reason we6292	 * need to make sure to add it back to the dead root list so that we6293	 * keep trying to do the work later.  This also cleans up roots if we6294	 * don't have it in the radix (like when we recover after a power fail6295	 * or unmount) so we don't leak memory.6296	 */6297	if (!for_reloc && !root_dropped)6298		btrfs_add_dead_root(root);6299	return ret;6300}6301 6302/*6303 * drop subtree rooted at tree block 'node'.6304 *6305 * NOTE: this function will unlock and release tree block 'node'6306 * only used by relocation code6307 */6308int btrfs_drop_subtree(struct btrfs_trans_handle *trans,6309			struct btrfs_root *root,6310			struct extent_buffer *node,6311			struct extent_buffer *parent)6312{6313	struct btrfs_fs_info *fs_info = root->fs_info;6314	struct btrfs_path *path;6315	struct walk_control *wc;6316	int level;6317	int parent_level;6318	int ret = 0;6319 6320	BUG_ON(btrfs_root_id(root) != BTRFS_TREE_RELOC_OBJECTID);6321 6322	path = btrfs_alloc_path();6323	if (!path)6324		return -ENOMEM;6325 6326	wc = kzalloc(sizeof(*wc), GFP_NOFS);6327	if (!wc) {6328		btrfs_free_path(path);6329		return -ENOMEM;6330	}6331 6332	btrfs_assert_tree_write_locked(parent);6333	parent_level = btrfs_header_level(parent);6334	atomic_inc(&parent->refs);6335	path->nodes[parent_level] = parent;6336	path->slots[parent_level] = btrfs_header_nritems(parent);6337 6338	btrfs_assert_tree_write_locked(node);6339	level = btrfs_header_level(node);6340	path->nodes[level] = node;6341	path->slots[level] = 0;6342	path->locks[level] = BTRFS_WRITE_LOCK;6343 6344	wc->refs[parent_level] = 1;6345	wc->flags[parent_level] = BTRFS_BLOCK_FLAG_FULL_BACKREF;6346	wc->level = level;6347	wc->shared_level = -1;6348	wc->stage = DROP_REFERENCE;6349	wc->update_ref = 0;6350	wc->keep_locks = 1;6351	wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(fs_info);6352 6353	while (1) {6354		ret = walk_down_tree(trans, root, path, wc);6355		if (ret < 0)6356			break;6357 6358		ret = walk_up_tree(trans, root, path, wc, parent_level);6359		if (ret) {6360			if (ret > 0)6361				ret = 0;6362			break;6363		}6364	}6365 6366	kfree(wc);6367	btrfs_free_path(path);6368	return ret;6369}6370 6371/*6372 * Unpin the extent range in an error context and don't add the space back.6373 * Errors are not propagated further.6374 */6375void btrfs_error_unpin_extent_range(struct btrfs_fs_info *fs_info, u64 start, u64 end)6376{6377	unpin_extent_range(fs_info, start, end, false);6378}6379 6380/*6381 * It used to be that old block groups would be left around forever.6382 * Iterating over them would be enough to trim unused space.  Since we6383 * now automatically remove them, we also need to iterate over unallocated6384 * space.6385 *6386 * We don't want a transaction for this since the discard may take a6387 * substantial amount of time.  We don't require that a transaction be6388 * running, but we do need to take a running transaction into account6389 * to ensure that we're not discarding chunks that were released or6390 * allocated in the current transaction.6391 *6392 * Holding the chunks lock will prevent other threads from allocating6393 * or releasing chunks, but it won't prevent a running transaction6394 * from committing and releasing the memory that the pending chunks6395 * list head uses.  For that, we need to take a reference to the6396 * transaction and hold the commit root sem.  We only need to hold6397 * it while performing the free space search since we have already6398 * held back allocations.6399 */6400static int btrfs_trim_free_extents(struct btrfs_device *device, u64 *trimmed)6401{6402	u64 start = BTRFS_DEVICE_RANGE_RESERVED, len = 0, end = 0;6403	int ret;6404 6405	*trimmed = 0;6406 6407	/* Discard not supported = nothing to do. */6408	if (!bdev_max_discard_sectors(device->bdev))6409		return 0;6410 6411	/* Not writable = nothing to do. */6412	if (!test_bit(BTRFS_DEV_STATE_WRITEABLE, &device->dev_state))6413		return 0;6414 6415	/* No free space = nothing to do. */6416	if (device->total_bytes <= device->bytes_used)6417		return 0;6418 6419	ret = 0;6420 6421	while (1) {6422		struct btrfs_fs_info *fs_info = device->fs_info;6423		u64 bytes;6424 6425		ret = mutex_lock_interruptible(&fs_info->chunk_mutex);6426		if (ret)6427			break;6428 6429		find_first_clear_extent_bit(&device->alloc_state, start,6430					    &start, &end,6431					    CHUNK_TRIMMED | CHUNK_ALLOCATED);6432 6433		/* Check if there are any CHUNK_* bits left */6434		if (start > device->total_bytes) {6435			WARN_ON(IS_ENABLED(CONFIG_BTRFS_DEBUG));6436			btrfs_warn_in_rcu(fs_info,6437"ignoring attempt to trim beyond device size: offset %llu length %llu device %s device size %llu",6438					  start, end - start + 1,6439					  btrfs_dev_name(device),6440					  device->total_bytes);6441			mutex_unlock(&fs_info->chunk_mutex);6442			ret = 0;6443			break;6444		}6445 6446		/* Ensure we skip the reserved space on each device. */6447		start = max_t(u64, start, BTRFS_DEVICE_RANGE_RESERVED);6448 6449		/*6450		 * If find_first_clear_extent_bit find a range that spans the6451		 * end of the device it will set end to -1, in this case it's up6452		 * to the caller to trim the value to the size of the device.6453		 */6454		end = min(end, device->total_bytes - 1);6455 6456		len = end - start + 1;6457 6458		/* We didn't find any extents */6459		if (!len) {6460			mutex_unlock(&fs_info->chunk_mutex);6461			ret = 0;6462			break;6463		}6464 6465		ret = btrfs_issue_discard(device->bdev, start, len,6466					  &bytes);6467		if (!ret)6468			set_extent_bit(&device->alloc_state, start,6469				       start + bytes - 1, CHUNK_TRIMMED, NULL);6470		mutex_unlock(&fs_info->chunk_mutex);6471 6472		if (ret)6473			break;6474 6475		start += len;6476		*trimmed += bytes;6477 6478		if (btrfs_trim_interrupted()) {6479			ret = -ERESTARTSYS;6480			break;6481		}6482 6483		cond_resched();6484	}6485 6486	return ret;6487}6488 6489/*6490 * Trim the whole filesystem by:6491 * 1) trimming the free space in each block group6492 * 2) trimming the unallocated space on each device6493 *6494 * This will also continue trimming even if a block group or device encounters6495 * an error.  The return value will be the last error, or 0 if nothing bad6496 * happens.6497 */6498int btrfs_trim_fs(struct btrfs_fs_info *fs_info, struct fstrim_range *range)6499{6500	struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;6501	struct btrfs_block_group *cache = NULL;6502	struct btrfs_device *device;6503	u64 group_trimmed;6504	u64 range_end = U64_MAX;6505	u64 start;6506	u64 end;6507	u64 trimmed = 0;6508	u64 bg_failed = 0;6509	u64 dev_failed = 0;6510	int bg_ret = 0;6511	int dev_ret = 0;6512	int ret = 0;6513 6514	if (range->start == U64_MAX)6515		return -EINVAL;6516 6517	/*6518	 * Check range overflow if range->len is set.6519	 * The default range->len is U64_MAX.6520	 */6521	if (range->len != U64_MAX &&6522	    check_add_overflow(range->start, range->len, &range_end))6523		return -EINVAL;6524 6525	cache = btrfs_lookup_first_block_group(fs_info, range->start);6526	for (; cache; cache = btrfs_next_block_group(cache)) {6527		if (cache->start >= range_end) {6528			btrfs_put_block_group(cache);6529			break;6530		}6531 6532		start = max(range->start, cache->start);6533		end = min(range_end, cache->start + cache->length);6534 6535		if (end - start >= range->minlen) {6536			if (!btrfs_block_group_done(cache)) {6537				ret = btrfs_cache_block_group(cache, true);6538				if (ret) {6539					bg_failed++;6540					bg_ret = ret;6541					continue;6542				}6543			}6544			ret = btrfs_trim_block_group(cache,6545						     &group_trimmed,6546						     start,6547						     end,6548						     range->minlen);6549 6550			trimmed += group_trimmed;6551			if (ret) {6552				bg_failed++;6553				bg_ret = ret;6554				continue;6555			}6556		}6557	}6558 6559	if (bg_failed)6560		btrfs_warn(fs_info,6561			"failed to trim %llu block group(s), last error %d",6562			bg_failed, bg_ret);6563 6564	mutex_lock(&fs_devices->device_list_mutex);6565	list_for_each_entry(device, &fs_devices->devices, dev_list) {6566		if (test_bit(BTRFS_DEV_STATE_MISSING, &device->dev_state))6567			continue;6568 6569		ret = btrfs_trim_free_extents(device, &group_trimmed);6570 6571		trimmed += group_trimmed;6572		if (ret) {6573			dev_failed++;6574			dev_ret = ret;6575			break;6576		}6577	}6578	mutex_unlock(&fs_devices->device_list_mutex);6579 6580	if (dev_failed)6581		btrfs_warn(fs_info,6582			"failed to trim %llu device(s), last error %d",6583			dev_failed, dev_ret);6584	range->len = trimmed;6585	if (bg_ret)6586		return bg_ret;6587	return dev_ret;6588}6589