[linux.git] / fs / btrfs / backref.h

/* SPDX-License-Identifier: GPL-2.0 */
/*
 * Copyright (C) 2011 STRATO.  All rights reserved.
 */

#ifndef BTRFS_BACKREF_H
#define BTRFS_BACKREF_H

#include <linux/btrfs.h>
#include "ulist.h"
#include "disk-io.h"
#include "extent_io.h"

struct inode_fs_paths {
	struct btrfs_path		*btrfs_path;
	struct btrfs_root		*fs_root;
	struct btrfs_data_container	*fspath;
};

typedef int (iterate_extent_inodes_t)(u64 inum, u64 offset, u64 root,
		void *ctx);

int extent_from_logical(struct btrfs_fs_info *fs_info, u64 logical,
			struct btrfs_path *path, struct btrfs_key *found_key,
			u64 *flags);

int tree_backref_for_extent(unsigned long *ptr, struct extent_buffer *eb,
			    struct btrfs_key *key, struct btrfs_extent_item *ei,
			    u32 item_size, u64 *out_root, u8 *out_level);

int iterate_extent_inodes(struct btrfs_fs_info *fs_info,
				u64 extent_item_objectid,
				u64 extent_offset, int search_commit_root,
				iterate_extent_inodes_t *iterate, void *ctx,
				bool ignore_offset);

int iterate_inodes_from_logical(u64 logical, struct btrfs_fs_info *fs_info,
				struct btrfs_path *path,
				iterate_extent_inodes_t *iterate, void *ctx,
				bool ignore_offset);

int paths_from_inode(u64 inum, struct inode_fs_paths *ipath);

int btrfs_find_all_leafs(struct btrfs_trans_handle *trans,
			 struct btrfs_fs_info *fs_info, u64 bytenr,
			 u64 time_seq, struct ulist **leafs,
			 const u64 *extent_item_pos, bool ignore_offset);
int btrfs_find_all_roots(struct btrfs_trans_handle *trans,
			 struct btrfs_fs_info *fs_info, u64 bytenr,
			 u64 time_seq, struct ulist **roots, bool ignore_offset);
char *btrfs_ref_to_path(struct btrfs_root *fs_root, struct btrfs_path *path,
			u32 name_len, unsigned long name_off,
			struct extent_buffer *eb_in, u64 parent,
			char *dest, u32 size);

struct btrfs_data_container *init_data_container(u32 total_bytes);
struct inode_fs_paths *init_ipath(s32 total_bytes, struct btrfs_root *fs_root,
					struct btrfs_path *path);
void free_ipath(struct inode_fs_paths *ipath);

int btrfs_find_one_extref(struct btrfs_root *root, u64 inode_objectid,
			  u64 start_off, struct btrfs_path *path,
			  struct btrfs_inode_extref **ret_extref,
			  u64 *found_off);
int btrfs_check_shared(struct btrfs_root *root, u64 inum, u64 bytenr,
		struct ulist *roots, struct ulist *tmp_ulist);

int __init btrfs_prelim_ref_init(void);
void __cold btrfs_prelim_ref_exit(void);

struct prelim_ref {
	struct rb_node rbnode;
	u64 root_id;
	struct btrfs_key key_for_search;
	int level;
	int count;
	struct extent_inode_elem *inode_list;
	u64 parent;
	u64 wanted_disk_byte;
};

/*
 * Iterate backrefs of one extent.
 *
 * Now it only supports iteration of tree block in commit root.
 */
struct btrfs_backref_iter {
	u64 bytenr;
	struct btrfs_path *path;
	struct btrfs_fs_info *fs_info;
	struct btrfs_key cur_key;
	u32 item_ptr;
	u32 cur_ptr;
	u32 end_ptr;
};

struct btrfs_backref_iter *btrfs_backref_iter_alloc(
		struct btrfs_fs_info *fs_info, gfp_t gfp_flag);

static inline void btrfs_backref_iter_free(struct btrfs_backref_iter *iter)
{
	if (!iter)
		return;
	btrfs_free_path(iter->path);
	kfree(iter);
}

static inline struct extent_buffer *btrfs_backref_get_eb(
		struct btrfs_backref_iter *iter)
{
	if (!iter)
		return NULL;
	return iter->path->nodes[0];
}

/*
 * For metadata with EXTENT_ITEM key (non-skinny) case, the first inline data
 * is btrfs_tree_block_info, without a btrfs_extent_inline_ref header.
 *
 * This helper determines if that's the case.
 */
static inline bool btrfs_backref_has_tree_block_info(
		struct btrfs_backref_iter *iter)
{
	if (iter->cur_key.type == BTRFS_EXTENT_ITEM_KEY &&
	    iter->cur_ptr - iter->item_ptr == sizeof(struct btrfs_extent_item))
		return true;
	return false;
}

int btrfs_backref_iter_start(struct btrfs_backref_iter *iter, u64 bytenr);

int btrfs_backref_iter_next(struct btrfs_backref_iter *iter);

static inline bool btrfs_backref_iter_is_inline_ref(
		struct btrfs_backref_iter *iter)
{
	if (iter->cur_key.type == BTRFS_EXTENT_ITEM_KEY ||
	    iter->cur_key.type == BTRFS_METADATA_ITEM_KEY)
		return true;
	return false;
}

static inline void btrfs_backref_iter_release(struct btrfs_backref_iter *iter)
{
	iter->bytenr = 0;
	iter->item_ptr = 0;
	iter->cur_ptr = 0;
	iter->end_ptr = 0;
	btrfs_release_path(iter->path);
	memset(&iter->cur_key, 0, sizeof(iter->cur_key));
}

/*
 * Backref cache related structures
 *
 * The whole objective of backref_cache is to build a bi-directional map
 * of tree blocks (represented by backref_node) and all their parents.
 */

/*
 * Represent a tree block in the backref cache
 */
struct btrfs_backref_node {
	struct {
		struct rb_node rb_node;
		u64 bytenr;
	}; /* Use rb_simple_node for search/insert */

	u64 new_bytenr;
	/* Objectid of tree block owner, can be not uptodate */
	u64 owner;
	/* Link to pending, changed or detached list */
	struct list_head list;

	/* List of upper level edges, which link this node to its parents */
	struct list_head upper;
	/* List of lower level edges, which link this node to its children */
	struct list_head lower;

	/* NULL if this node is not tree root */
	struct btrfs_root *root;
	/* Extent buffer got by COWing the block */
	struct extent_buffer *eb;
	/* Level of the tree block */
	unsigned int level:8;
	/* Is the block in a non-shareable tree */
	unsigned int cowonly:1;
	/* 1 if no child node is in the cache */
	unsigned int lowest:1;
	/* Is the extent buffer locked */
	unsigned int locked:1;
	/* Has the block been processed */
	unsigned int processed:1;
	/* Have backrefs of this block been checked */
	unsigned int checked:1;
	/*
	 * 1 if corresponding block has been COWed but some upper level block
	 * pointers may not point to the new location
	 */
	unsigned int pending:1;
	/* 1 if the backref node isn't connected to any other backref node */
	unsigned int detached:1;

	/*
	 * For generic purpose backref cache, where we only care if it's a reloc
	 * root, doesn't care the source subvolid.
	 */
	unsigned int is_reloc_root:1;
};

#define LOWER	0
#define UPPER	1

/*
 * Represent an edge connecting upper and lower backref nodes.
 */
struct btrfs_backref_edge {
	/*
	 * list[LOWER] is linked to btrfs_backref_node::upper of lower level
	 * node, and list[UPPER] is linked to btrfs_backref_node::lower of
	 * upper level node.
	 *
	 * Also, build_backref_tree() uses list[UPPER] for pending edges, before
	 * linking list[UPPER] to its upper level nodes.
	 */
	struct list_head list[2];

	/* Two related nodes */
	struct btrfs_backref_node *node[2];
};

struct btrfs_backref_cache {
	/* Red black tree of all backref nodes in the cache */
	struct rb_root rb_root;
	/* For passing backref nodes to btrfs_reloc_cow_block */
	struct btrfs_backref_node *path[BTRFS_MAX_LEVEL];
	/*
	 * List of blocks that have been COWed but some block pointers in upper
	 * level blocks may not reflect the new location
	 */
	struct list_head pending[BTRFS_MAX_LEVEL];
	/* List of backref nodes with no child node */
	struct list_head leaves;
	/* List of blocks that have been COWed in current transaction */
	struct list_head changed;
	/* List of detached backref node. */
	struct list_head detached;

	u64 last_trans;

	int nr_nodes;
	int nr_edges;

	/* List of unchecked backref edges during backref cache build */
	struct list_head pending_edge;

	/* List of useless backref nodes during backref cache build */
	struct list_head useless_node;

	struct btrfs_fs_info *fs_info;

	/*
	 * Whether this cache is for relocation
	 *
	 * Reloction backref cache require more info for reloc root compared
	 * to generic backref cache.
	 */
	unsigned int is_reloc;
};

void btrfs_backref_init_cache(struct btrfs_fs_info *fs_info,
			      struct btrfs_backref_cache *cache, int is_reloc);
struct btrfs_backref_node *btrfs_backref_alloc_node(
		struct btrfs_backref_cache *cache, u64 bytenr, int level);
struct btrfs_backref_edge *btrfs_backref_alloc_edge(
		struct btrfs_backref_cache *cache);

#define		LINK_LOWER	(1 << 0)
#define		LINK_UPPER	(1 << 1)
static inline void btrfs_backref_link_edge(struct btrfs_backref_edge *edge,
					   struct btrfs_backref_node *lower,
					   struct btrfs_backref_node *upper,
					   int link_which)
{
	ASSERT(upper && lower && upper->level == lower->level + 1);
	edge->node[LOWER] = lower;
	edge->node[UPPER] = upper;
	if (link_which & LINK_LOWER)
		list_add_tail(&edge->list[LOWER], &lower->upper);
	if (link_which & LINK_UPPER)
		list_add_tail(&edge->list[UPPER], &upper->lower);
}

static inline void btrfs_backref_free_node(struct btrfs_backref_cache *cache,
					   struct btrfs_backref_node *node)
{
	if (node) {
		cache->nr_nodes--;
		btrfs_put_root(node->root);
		kfree(node);
	}
}

static inline void btrfs_backref_free_edge(struct btrfs_backref_cache *cache,
					   struct btrfs_backref_edge *edge)
{
	if (edge) {
		cache->nr_edges--;
		kfree(edge);
	}
}

static inline void btrfs_backref_unlock_node_buffer(
		struct btrfs_backref_node *node)
{
	if (node->locked) {
		btrfs_tree_unlock(node->eb);
		node->locked = 0;
	}
}

static inline void btrfs_backref_drop_node_buffer(
		struct btrfs_backref_node *node)
{
	if (node->eb) {
		btrfs_backref_unlock_node_buffer(node);
		free_extent_buffer(node->eb);
		node->eb = NULL;
	}
}

/*
 * Drop the backref node from cache without cleaning up its children
 * edges.
 *
 * This can only be called on node without parent edges.
 * The children edges are still kept as is.
 */
static inline void btrfs_backref_drop_node(struct btrfs_backref_cache *tree,
					   struct btrfs_backref_node *node)
{
	BUG_ON(!list_empty(&node->upper));

	btrfs_backref_drop_node_buffer(node);
	list_del(&node->list);
	list_del(&node->lower);
	if (!RB_EMPTY_NODE(&node->rb_node))
		rb_erase(&node->rb_node, &tree->rb_root);
	btrfs_backref_free_node(tree, node);
}

void btrfs_backref_cleanup_node(struct btrfs_backref_cache *cache,
				struct btrfs_backref_node *node);

void btrfs_backref_release_cache(struct btrfs_backref_cache *cache);

static inline void btrfs_backref_panic(struct btrfs_fs_info *fs_info,
				       u64 bytenr, int errno)
{
	btrfs_panic(fs_info, errno,
		    "Inconsistency in backref cache found at offset %llu",
		    bytenr);
}

int btrfs_backref_add_tree_node(struct btrfs_backref_cache *cache,
				struct btrfs_path *path,
				struct btrfs_backref_iter *iter,
				struct btrfs_key *node_key,
				struct btrfs_backref_node *cur);

int btrfs_backref_finish_upper_links(struct btrfs_backref_cache *cache,
				     struct btrfs_backref_node *start);

void btrfs_backref_error_cleanup(struct btrfs_backref_cache *cache,
				 struct btrfs_backref_node *node);

#endif
Commit	Line	Data
9888c340	1	/* SPDX-License-Identifier: GPL-2.0 */
a542ad1b JS	2	/*
a542ad1b JS	3	* Copyright (C) 2011 STRATO. All rights reserved.
a542ad1b JS	4	*/
a542ad1b JS	5
9888c340 DS	6	#ifndef BTRFS_BACKREF_H
9888c340 DS	7	#define BTRFS_BACKREF_H
a542ad1b	8
55e301fd	9	#include <linux/btrfs.h>
8da6d581	10	#include "ulist.h"
741188d3	11	#include "disk-io.h"
91cb916c	12	#include "extent_io.h"
a542ad1b JS	13
	14	struct inode_fs_paths {
	15	struct btrfs_path *btrfs_path;
	16	struct btrfs_root *fs_root;
	17	struct btrfs_data_container *fspath;
	18	};
	19
	20	typedef int (iterate_extent_inodes_t)(u64 inum, u64 offset, u64 root,
	21	void *ctx);
a542ad1b	22
a542ad1b	23	int extent_from_logical(struct btrfs_fs_info *fs_info, u64 logical,
69917e43 LB	24	struct btrfs_path path, struct btrfs_key found_key,
69917e43 LB	25	u64 *flags);
a542ad1b JS	26
a542ad1b JS	27	int tree_backref_for_extent(unsigned long ptr, struct extent_buffer eb,
6eda71d0 LB	28	struct btrfs_key key, struct btrfs_extent_item ei,
6eda71d0 LB	29	u32 item_size, u64 out_root, u8 out_level);
a542ad1b JS	30
a542ad1b JS	31	int iterate_extent_inodes(struct btrfs_fs_info *fs_info,
a542ad1b	32	u64 extent_item_objectid,
7a3ae2f8	33	u64 extent_offset, int search_commit_root,
c995ab3c ZB	34	iterate_extent_inodes_t iterate, void ctx,
c995ab3c ZB	35	bool ignore_offset);
a542ad1b JS	36
	37	int iterate_inodes_from_logical(u64 logical, struct btrfs_fs_info *fs_info,
	38	struct btrfs_path *path,
c995ab3c ZB	39	iterate_extent_inodes_t iterate, void ctx,
c995ab3c ZB	40	bool ignore_offset);
a542ad1b JS	41
	42	int paths_from_inode(u64 inum, struct inode_fs_paths *ipath);
	43
19b546d7 QW	44	int btrfs_find_all_leafs(struct btrfs_trans_handle *trans,
	45	struct btrfs_fs_info *fs_info, u64 bytenr,
	46	u64 time_seq, struct ulist **leafs,
	47	const u64 *extent_item_pos, bool ignore_offset);
8da6d581	48	int btrfs_find_all_roots(struct btrfs_trans_handle *trans,
fcebe456	49	struct btrfs_fs_info *fs_info, u64 bytenr,
c995ab3c	50	u64 time_seq, struct ulist **roots, bool ignore_offset);
96b5bd77 JS	51	char btrfs_ref_to_path(struct btrfs_root fs_root, struct btrfs_path *path,
	52	u32 name_len, unsigned long name_off,
	53	struct extent_buffer *eb_in, u64 parent,
	54	char *dest, u32 size);
8da6d581	55
a542ad1b JS	56	struct btrfs_data_container *init_data_container(u32 total_bytes);
	57	struct inode_fs_paths init_ipath(s32 total_bytes, struct btrfs_root fs_root,
	58	struct btrfs_path *path);
	59	void free_ipath(struct inode_fs_paths *ipath);
	60
f186373f MF	61	int btrfs_find_one_extref(struct btrfs_root *root, u64 inode_objectid,
	62	u64 start_off, struct btrfs_path *path,
	63	struct btrfs_inode_extref **ret_extref,
	64	u64 *found_off);
5911c8fe DS	65	int btrfs_check_shared(struct btrfs_root *root, u64 inum, u64 bytenr,
5911c8fe DS	66	struct ulist roots, struct ulist tmp_ulist);
f186373f	67
b9e9a6cb	68	int __init btrfs_prelim_ref_init(void);
e67c718b	69	void __cold btrfs_prelim_ref_exit(void);
00142756 JM	70
	71	struct prelim_ref {
	72	struct rb_node rbnode;
	73	u64 root_id;
	74	struct btrfs_key key_for_search;
	75	int level;
	76	int count;
	77	struct extent_inode_elem *inode_list;
	78	u64 parent;
	79	u64 wanted_disk_byte;
	80	};
	81
a37f232b QW	82	/*
	83	* Iterate backrefs of one extent.
	84	*
	85	* Now it only supports iteration of tree block in commit root.
	86	*/
	87	struct btrfs_backref_iter {
	88	u64 bytenr;
	89	struct btrfs_path *path;
	90	struct btrfs_fs_info *fs_info;
	91	struct btrfs_key cur_key;
	92	u32 item_ptr;
	93	u32 cur_ptr;
	94	u32 end_ptr;
	95	};
	96
	97	struct btrfs_backref_iter *btrfs_backref_iter_alloc(
	98	struct btrfs_fs_info *fs_info, gfp_t gfp_flag);
	99
	100	static inline void btrfs_backref_iter_free(struct btrfs_backref_iter *iter)
	101	{
	102	if (!iter)
	103	return;
	104	btrfs_free_path(iter->path);
	105	kfree(iter);
	106	}
	107
c39c2ddc QW	108	static inline struct extent_buffer *btrfs_backref_get_eb(
	109	struct btrfs_backref_iter *iter)
	110	{
	111	if (!iter)
	112	return NULL;
	113	return iter->path->nodes[0];
	114	}
	115
	116	/*
	117	* For metadata with EXTENT_ITEM key (non-skinny) case, the first inline data
	118	* is btrfs_tree_block_info, without a btrfs_extent_inline_ref header.
	119	*
	120	* This helper determines if that's the case.
	121	*/
	122	static inline bool btrfs_backref_has_tree_block_info(
	123	struct btrfs_backref_iter *iter)
	124	{
	125	if (iter->cur_key.type == BTRFS_EXTENT_ITEM_KEY &&
	126	iter->cur_ptr - iter->item_ptr == sizeof(struct btrfs_extent_item))
	127	return true;
	128	return false;
	129	}
	130
a37f232b QW	131	int btrfs_backref_iter_start(struct btrfs_backref_iter *iter, u64 bytenr);
a37f232b QW	132
c39c2ddc QW	133	int btrfs_backref_iter_next(struct btrfs_backref_iter *iter);
	134
	135	static inline bool btrfs_backref_iter_is_inline_ref(
	136	struct btrfs_backref_iter *iter)
	137	{
	138	if (iter->cur_key.type == BTRFS_EXTENT_ITEM_KEY \|\|
	139	iter->cur_key.type == BTRFS_METADATA_ITEM_KEY)
	140	return true;
	141	return false;
	142	}
	143
a37f232b QW	144	static inline void btrfs_backref_iter_release(struct btrfs_backref_iter *iter)
	145	{
	146	iter->bytenr = 0;
	147	iter->item_ptr = 0;
	148	iter->cur_ptr = 0;
	149	iter->end_ptr = 0;
	150	btrfs_release_path(iter->path);
	151	memset(&iter->cur_key, 0, sizeof(iter->cur_key));
	152	}
	153
70535441 QW	154	/*
	155	* Backref cache related structures
	156	*
	157	* The whole objective of backref_cache is to build a bi-directional map
	158	* of tree blocks (represented by backref_node) and all their parents.
	159	*/
	160
	161	/*
	162	* Represent a tree block in the backref cache
	163	*/
	164	struct btrfs_backref_node {
e9a28dc5 QW	165	struct {
	166	struct rb_node rb_node;
	167	u64 bytenr;
	168	}; /* Use rb_simple_node for search/insert */
70535441 QW	169
	170	u64 new_bytenr;
	171	/* Objectid of tree block owner, can be not uptodate */
	172	u64 owner;
	173	/* Link to pending, changed or detached list */
	174	struct list_head list;
	175
	176	/* List of upper level edges, which link this node to its parents */
	177	struct list_head upper;
	178	/* List of lower level edges, which link this node to its children */
	179	struct list_head lower;
	180
	181	/* NULL if this node is not tree root */
	182	struct btrfs_root *root;
	183	/* Extent buffer got by COWing the block */
	184	struct extent_buffer *eb;
	185	/* Level of the tree block */
	186	unsigned int level:8;
92a7cc42	187	/* Is the block in a non-shareable tree */
70535441 QW	188	unsigned int cowonly:1;
	189	/* 1 if no child node is in the cache */
	190	unsigned int lowest:1;
	191	/* Is the extent buffer locked */
	192	unsigned int locked:1;
	193	/* Has the block been processed */
	194	unsigned int processed:1;
	195	/* Have backrefs of this block been checked */
	196	unsigned int checked:1;
	197	/*
	198	* 1 if corresponding block has been COWed but some upper level block
	199	* pointers may not point to the new location
	200	*/
	201	unsigned int pending:1;
	202	/* 1 if the backref node isn't connected to any other backref node */
	203	unsigned int detached:1;
	204
	205	/*
	206	* For generic purpose backref cache, where we only care if it's a reloc
	207	* root, doesn't care the source subvolid.
	208	*/
	209	unsigned int is_reloc_root:1;
	210	};
	211
	212	#define LOWER 0
	213	#define UPPER 1
	214
	215	/*
	216	* Represent an edge connecting upper and lower backref nodes.
	217	*/
	218	struct btrfs_backref_edge {
	219	/*
	220	* list[LOWER] is linked to btrfs_backref_node::upper of lower level
	221	* node, and list[UPPER] is linked to btrfs_backref_node::lower of
	222	* upper level node.
	223	*
	224	* Also, build_backref_tree() uses list[UPPER] for pending edges, before
	225	* linking list[UPPER] to its upper level nodes.
	226	*/
	227	struct list_head list[2];
	228
	229	/* Two related nodes */
	230	struct btrfs_backref_node *node[2];
	231	};
	232
	233	struct btrfs_backref_cache {
	234	/* Red black tree of all backref nodes in the cache */
	235	struct rb_root rb_root;
	236	/* For passing backref nodes to btrfs_reloc_cow_block */
	237	struct btrfs_backref_node *path[BTRFS_MAX_LEVEL];
	238	/*
	239	* List of blocks that have been COWed but some block pointers in upper
	240	* level blocks may not reflect the new location
	241	*/
	242	struct list_head pending[BTRFS_MAX_LEVEL];
	243	/* List of backref nodes with no child node */
	244	struct list_head leaves;
	245	/* List of blocks that have been COWed in current transaction */
	246	struct list_head changed;
	247	/* List of detached backref node. */
	248	struct list_head detached;
	249
	250	u64 last_trans;
	251
252	int nr_nodes;
253	int nr_edges;
254
255	/* List of unchecked backref edges during backref cache build */
256	struct list_head pending_edge;
257
258	/* List of useless backref nodes during backref cache build */
259	struct list_head useless_node;
260
261	struct btrfs_fs_info *fs_info;
262
263	/*
264	* Whether this cache is for relocation
265	*
266	* Reloction backref cache require more info for reloc root compared
267	* to generic backref cache.
268	*/
269	unsigned int is_reloc;
270	};
271
584fb121 QW	272	void btrfs_backref_init_cache(struct btrfs_fs_info *fs_info,
584fb121 QW	273	struct btrfs_backref_cache *cache, int is_reloc);
b1818dab QW	274	struct btrfs_backref_node *btrfs_backref_alloc_node(
b1818dab QW	275	struct btrfs_backref_cache *cache, u64 bytenr, int level);
47254d07 QW	276	struct btrfs_backref_edge *btrfs_backref_alloc_edge(
47254d07 QW	277	struct btrfs_backref_cache *cache);
584fb121	278
f39911e5 QW	279	#define LINK_LOWER (1 << 0)
	280	#define LINK_UPPER (1 << 1)
	281	static inline void btrfs_backref_link_edge(struct btrfs_backref_edge *edge,
	282	struct btrfs_backref_node *lower,
	283	struct btrfs_backref_node *upper,
	284	int link_which)
	285	{
	286	ASSERT(upper && lower && upper->level == lower->level + 1);
	287	edge->node[LOWER] = lower;
	288	edge->node[UPPER] = upper;
	289	if (link_which & LINK_LOWER)
	290	list_add_tail(&edge->list[LOWER], &lower->upper);
	291	if (link_which & LINK_UPPER)
	292	list_add_tail(&edge->list[UPPER], &upper->lower);
	293	}
	294
741188d3 QW	295	static inline void btrfs_backref_free_node(struct btrfs_backref_cache *cache,
	296	struct btrfs_backref_node *node)
	297	{
	298	if (node) {
	299	cache->nr_nodes--;
	300	btrfs_put_root(node->root);
	301	kfree(node);
	302	}
	303	}
	304
	305	static inline void btrfs_backref_free_edge(struct btrfs_backref_cache *cache,
	306	struct btrfs_backref_edge *edge)
	307	{
	308	if (edge) {
	309	cache->nr_edges--;
	310	kfree(edge);
	311	}
	312	}
	313
b0fe7078 QW	314	static inline void btrfs_backref_unlock_node_buffer(
	315	struct btrfs_backref_node *node)
	316	{
	317	if (node->locked) {
	318	btrfs_tree_unlock(node->eb);
	319	node->locked = 0;
	320	}
	321	}
	322
	323	static inline void btrfs_backref_drop_node_buffer(
	324	struct btrfs_backref_node *node)
	325	{
	326	if (node->eb) {
	327	btrfs_backref_unlock_node_buffer(node);
	328	free_extent_buffer(node->eb);
	329	node->eb = NULL;
	330	}
	331	}
	332
	333	/*
	334	* Drop the backref node from cache without cleaning up its children
	335	* edges.
	336	*
	337	* This can only be called on node without parent edges.
	338	* The children edges are still kept as is.
	339	*/
	340	static inline void btrfs_backref_drop_node(struct btrfs_backref_cache *tree,
	341	struct btrfs_backref_node *node)
	342	{
	343	BUG_ON(!list_empty(&node->upper));
	344
	345	btrfs_backref_drop_node_buffer(node);
	346	list_del(&node->list);
	347	list_del(&node->lower);
	348	if (!RB_EMPTY_NODE(&node->rb_node))
	349	rb_erase(&node->rb_node, &tree->rb_root);
	350	btrfs_backref_free_node(tree, node);
	351	}
	352
023acb07 QW	353	void btrfs_backref_cleanup_node(struct btrfs_backref_cache *cache,
	354	struct btrfs_backref_node *node);
	355
13fe1bdb QW	356	void btrfs_backref_release_cache(struct btrfs_backref_cache *cache);
13fe1bdb QW	357
982c92cb QW	358	static inline void btrfs_backref_panic(struct btrfs_fs_info *fs_info,
	359	u64 bytenr, int errno)
	360	{
	361	btrfs_panic(fs_info, errno,
	362	"Inconsistency in backref cache found at offset %llu",
	363	bytenr);
	364	}
	365
1b60d2ec QW	366	int btrfs_backref_add_tree_node(struct btrfs_backref_cache *cache,
	367	struct btrfs_path *path,
	368	struct btrfs_backref_iter *iter,
	369	struct btrfs_key *node_key,
	370	struct btrfs_backref_node *cur);
	371
fc997ed0 QW	372	int btrfs_backref_finish_upper_links(struct btrfs_backref_cache *cache,
	373	struct btrfs_backref_node *start);
	374
1b23ea18 QW	375	void btrfs_backref_error_cleanup(struct btrfs_backref_cache *cache,
	376	struct btrfs_backref_node *node);
	377
a542ad1b	378	#endif