[deliverable/linux.git] / fs / btrfs / delayed-ref.h

/*
 * Copyright (C) 2008 Oracle.  All rights reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public
 * License v2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public
 * License along with this program; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 021110-1307, USA.
 */
#ifndef __DELAYED_REF__
#define __DELAYED_REF__

/* these are the possible values of struct btrfs_delayed_ref_node->action */
#define BTRFS_ADD_DELAYED_REF    1 /* add one backref to the tree */
#define BTRFS_DROP_DELAYED_REF   2 /* delete one backref from the tree */
#define BTRFS_ADD_DELAYED_EXTENT 3 /* record a full extent allocation */
#define BTRFS_UPDATE_DELAYED_HEAD 4 /* not changing ref count on head ref */

struct btrfs_delayed_ref_node {
	struct rb_node rb_node;

	/* the starting bytenr of the extent */
	u64 bytenr;

	/* the size of the extent */
	u64 num_bytes;

	/* seq number to keep track of insertion order */
	u64 seq;

	/* ref count on this data structure */
	atomic_t refs;

	/*
	 * how many refs is this entry adding or deleting.  For
	 * head refs, this may be a negative number because it is keeping
	 * track of the total mods done to the reference count.
	 * For individual refs, this will always be a positive number
	 *
	 * It may be more than one, since it is possible for a single
	 * parent to have more than one ref on an extent
	 */
	int ref_mod;

	unsigned int action:8;
	unsigned int type:8;
	/* is this node still in the rbtree? */
	unsigned int is_head:1;
	unsigned int in_tree:1;
};

struct btrfs_delayed_extent_op {
	struct btrfs_disk_key key;
	u64 flags_to_set;
	unsigned int update_key:1;
	unsigned int update_flags:1;
	unsigned int is_data:1;
};

/*
 * the head refs are used to hold a lock on a given extent, which allows us
 * to make sure that only one process is running the delayed refs
 * at a time for a single extent.  They also store the sum of all the
 * reference count modifications we've queued up.
 */
struct btrfs_delayed_ref_head {
	struct btrfs_delayed_ref_node node;

	/*
	 * the mutex is held while running the refs, and it is also
	 * held when checking the sum of reference modifications.
	 */
	struct mutex mutex;

	struct list_head cluster;

	struct btrfs_delayed_extent_op *extent_op;
	/*
	 * when a new extent is allocated, it is just reserved in memory
	 * The actual extent isn't inserted into the extent allocation tree
	 * until the delayed ref is processed.  must_insert_reserved is
	 * used to flag a delayed ref so the accounting can be updated
	 * when a full insert is done.
	 *
	 * It is possible the extent will be freed before it is ever
	 * inserted into the extent allocation tree.  In this case
	 * we need to update the in ram accounting to properly reflect
	 * the free has happened.
	 */
	unsigned int must_insert_reserved:1;
	unsigned int is_data:1;
};

struct btrfs_delayed_tree_ref {
	struct btrfs_delayed_ref_node node;
	u64 root;
	u64 parent;
	int level;
};

struct btrfs_delayed_data_ref {
	struct btrfs_delayed_ref_node node;
	u64 root;
	u64 parent;
	u64 objectid;
	u64 offset;
};

struct btrfs_delayed_ref_root {
	struct rb_root root;

	/* this spin lock protects the rbtree and the entries inside */
	spinlock_t lock;

	/* how many delayed ref updates we've queued, used by the
	 * throttling code
	 */
	unsigned long num_entries;

	/* total number of head nodes in tree */
	unsigned long num_heads;

	/* total number of head nodes ready for processing */
	unsigned long num_heads_ready;

	/*
	 * set when the tree is flushing before a transaction commit,
	 * used by the throttling code to decide if new updates need
	 * to be run right away
	 */
	int flushing;

	u64 run_delayed_start;
};

extern struct kmem_cache *btrfs_delayed_ref_head_cachep;
extern struct kmem_cache *btrfs_delayed_tree_ref_cachep;
extern struct kmem_cache *btrfs_delayed_data_ref_cachep;
extern struct kmem_cache *btrfs_delayed_extent_op_cachep;

int btrfs_delayed_ref_init(void);
void btrfs_delayed_ref_exit(void);

static inline struct btrfs_delayed_extent_op *
btrfs_alloc_delayed_extent_op(void)
{
	return kmem_cache_alloc(btrfs_delayed_extent_op_cachep, GFP_NOFS);
}

static inline void
btrfs_free_delayed_extent_op(struct btrfs_delayed_extent_op *op)
{
	if (op)
		kmem_cache_free(btrfs_delayed_extent_op_cachep, op);
}

static inline void btrfs_put_delayed_ref(struct btrfs_delayed_ref_node *ref)
{
	WARN_ON(atomic_read(&ref->refs) == 0);
	if (atomic_dec_and_test(&ref->refs)) {
		WARN_ON(ref->in_tree);
		switch (ref->type) {
		case BTRFS_TREE_BLOCK_REF_KEY:
		case BTRFS_SHARED_BLOCK_REF_KEY:
			kmem_cache_free(btrfs_delayed_tree_ref_cachep, ref);
			break;
		case BTRFS_EXTENT_DATA_REF_KEY:
		case BTRFS_SHARED_DATA_REF_KEY:
			kmem_cache_free(btrfs_delayed_data_ref_cachep, ref);
			break;
		case 0:
			kmem_cache_free(btrfs_delayed_ref_head_cachep, ref);
			break;
		default:
			BUG();
		}
	}
}

int btrfs_add_delayed_tree_ref(struct btrfs_fs_info *fs_info,
			       struct btrfs_trans_handle *trans,
			       u64 bytenr, u64 num_bytes, u64 parent,
			       u64 ref_root, int level, int action,
			       struct btrfs_delayed_extent_op *extent_op,
			       int for_cow);
int btrfs_add_delayed_data_ref(struct btrfs_fs_info *fs_info,
			       struct btrfs_trans_handle *trans,
			       u64 bytenr, u64 num_bytes,
			       u64 parent, u64 ref_root,
			       u64 owner, u64 offset, int action,
			       struct btrfs_delayed_extent_op *extent_op,
			       int for_cow);
int btrfs_add_delayed_extent_op(struct btrfs_fs_info *fs_info,
				struct btrfs_trans_handle *trans,
				u64 bytenr, u64 num_bytes,
				struct btrfs_delayed_extent_op *extent_op);
void btrfs_merge_delayed_refs(struct btrfs_trans_handle *trans,
			      struct btrfs_fs_info *fs_info,
			      struct btrfs_delayed_ref_root *delayed_refs,
			      struct btrfs_delayed_ref_head *head);

struct btrfs_delayed_ref_head *
btrfs_find_delayed_ref_head(struct btrfs_trans_handle *trans, u64 bytenr);
int btrfs_delayed_ref_lock(struct btrfs_trans_handle *trans,
			   struct btrfs_delayed_ref_head *head);
int btrfs_find_ref_cluster(struct btrfs_trans_handle *trans,
			   struct list_head *cluster, u64 search_start);

int btrfs_check_delayed_seq(struct btrfs_fs_info *fs_info,
			    struct btrfs_delayed_ref_root *delayed_refs,
			    u64 seq);

/*
 * delayed refs with a ref_seq > 0 must be held back during backref walking.
 * this only applies to items in one of the fs-trees. for_cow items never need
 * to be held back, so they won't get a ref_seq number.
 */
static inline int need_ref_seq(int for_cow, u64 rootid)
{
	if (for_cow)
		return 0;

	if (rootid == BTRFS_FS_TREE_OBJECTID)
		return 1;

	if ((s64)rootid >= (s64)BTRFS_FIRST_FREE_OBJECTID)
		return 1;

	return 0;
}

/*
 * a node might live in a head or a regular ref, this lets you
 * test for the proper type to use.
 */
static int btrfs_delayed_ref_is_head(struct btrfs_delayed_ref_node *node)
{
	return node->is_head;
}

/*
 * helper functions to cast a node into its container
 */
static inline struct btrfs_delayed_tree_ref *
btrfs_delayed_node_to_tree_ref(struct btrfs_delayed_ref_node *node)
{
	WARN_ON(btrfs_delayed_ref_is_head(node));
	return container_of(node, struct btrfs_delayed_tree_ref, node);
}

static inline struct btrfs_delayed_data_ref *
btrfs_delayed_node_to_data_ref(struct btrfs_delayed_ref_node *node)
{
	WARN_ON(btrfs_delayed_ref_is_head(node));
	return container_of(node, struct btrfs_delayed_data_ref, node);
}

static inline struct btrfs_delayed_ref_head *
btrfs_delayed_node_to_head(struct btrfs_delayed_ref_node *node)
{
	WARN_ON(!btrfs_delayed_ref_is_head(node));
	return container_of(node, struct btrfs_delayed_ref_head, node);
}
#endif
Commit	Line	Data
56bec294 CM	1	/*
	2	* Copyright (C) 2008 Oracle. All rights reserved.
	3	*
	4	* This program is free software; you can redistribute it and/or
	5	* modify it under the terms of the GNU General Public
	6	* License v2 as published by the Free Software Foundation.
	7	*
	8	* This program is distributed in the hope that it will be useful,
	9	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	10	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	11	* General Public License for more details.
	12	*
	13	* You should have received a copy of the GNU General Public
	14	* License along with this program; if not, write to the
	15	* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
	16	* Boston, MA 021110-1307, USA.
	17	*/
	18	#ifndef __DELAYED_REF__
	19	#define __DELAYED_REF__
	20
44a075bd	21	/* these are the possible values of struct btrfs_delayed_ref_node->action */
56bec294 CM	22	#define BTRFS_ADD_DELAYED_REF 1 /* add one backref to the tree */
	23	#define BTRFS_DROP_DELAYED_REF 2 /* delete one backref from the tree */
	24	#define BTRFS_ADD_DELAYED_EXTENT 3 /* record a full extent allocation */
1a81af4d	25	#define BTRFS_UPDATE_DELAYED_HEAD 4 /* not changing ref count on head ref */
56bec294 CM	26
	27	struct btrfs_delayed_ref_node {
	28	struct rb_node rb_node;
	29
	30	/* the starting bytenr of the extent */
	31	u64 bytenr;
	32
56bec294 CM	33	/* the size of the extent */
	34	u64 num_bytes;
	35
00f04b88 AJ	36	/* seq number to keep track of insertion order */
	37	u64 seq;
	38
56bec294 CM	39	/* ref count on this data structure */
	40	atomic_t refs;
	41
	42	/*
	43	* how many refs is this entry adding or deleting. For
	44	* head refs, this may be a negative number because it is keeping
	45	* track of the total mods done to the reference count.
	46	* For individual refs, this will always be a positive number
	47	*
	48	* It may be more than one, since it is possible for a single
	49	* parent to have more than one ref on an extent
	50	*/
	51	int ref_mod;
	52
5d4f98a2 YZ	53	unsigned int action:8;
5d4f98a2 YZ	54	unsigned int type:8;
56bec294	55	/* is this node still in the rbtree? */
5d4f98a2	56	unsigned int is_head:1;
56bec294 CM	57	unsigned int in_tree:1;
	58	};
	59
5d4f98a2 YZ	60	struct btrfs_delayed_extent_op {
	61	struct btrfs_disk_key key;
	62	u64 flags_to_set;
	63	unsigned int update_key:1;
	64	unsigned int update_flags:1;
	65	unsigned int is_data:1;
	66	};
	67
56bec294 CM	68	/*
	69	* the head refs are used to hold a lock on a given extent, which allows us
	70	* to make sure that only one process is running the delayed refs
	71	* at a time for a single extent. They also store the sum of all the
	72	* reference count modifications we've queued up.
	73	*/
	74	struct btrfs_delayed_ref_head {
	75	struct btrfs_delayed_ref_node node;
	76
	77	/*
	78	* the mutex is held while running the refs, and it is also
	79	* held when checking the sum of reference modifications.
	80	*/
	81	struct mutex mutex;
	82
c3e69d58 CM	83	struct list_head cluster;
c3e69d58 CM	84
5d4f98a2	85	struct btrfs_delayed_extent_op *extent_op;
56bec294 CM	86	/*
	87	* when a new extent is allocated, it is just reserved in memory
	88	* The actual extent isn't inserted into the extent allocation tree
	89	* until the delayed ref is processed. must_insert_reserved is
	90	* used to flag a delayed ref so the accounting can be updated
	91	* when a full insert is done.
	92	*
	93	* It is possible the extent will be freed before it is ever
	94	* inserted into the extent allocation tree. In this case
	95	* we need to update the in ram accounting to properly reflect
	96	* the free has happened.
	97	*/
	98	unsigned int must_insert_reserved:1;
5d4f98a2	99	unsigned int is_data:1;
56bec294 CM	100	};
56bec294 CM	101
5d4f98a2	102	struct btrfs_delayed_tree_ref {
56bec294	103	struct btrfs_delayed_ref_node node;
eebe063b AJ	104	u64 root;
eebe063b AJ	105	u64 parent;
5d4f98a2 YZ	106	int level;
5d4f98a2 YZ	107	};
56bec294	108
5d4f98a2 YZ	109	struct btrfs_delayed_data_ref {
5d4f98a2 YZ	110	struct btrfs_delayed_ref_node node;
eebe063b AJ	111	u64 root;
eebe063b AJ	112	u64 parent;
5d4f98a2 YZ	113	u64 objectid;
5d4f98a2 YZ	114	u64 offset;
56bec294 CM	115	};
	116
	117	struct btrfs_delayed_ref_root {
	118	struct rb_root root;
	119
	120	/* this spin lock protects the rbtree and the entries inside */
	121	spinlock_t lock;
	122
	123	/* how many delayed ref updates we've queued, used by the
	124	* throttling code
	125	*/
	126	unsigned long num_entries;
	127
c3e69d58 CM	128	/* total number of head nodes in tree */
	129	unsigned long num_heads;
	130
	131	/* total number of head nodes ready for processing */
	132	unsigned long num_heads_ready;
	133
56bec294 CM	134	/*
	135	* set when the tree is flushing before a transaction commit,
	136	* used by the throttling code to decide if new updates need
	137	* to be run right away
	138	*/
	139	int flushing;
c3e69d58 CM	140
c3e69d58 CM	141	u64 run_delayed_start;
56bec294 CM	142	};
56bec294 CM	143
78a6184a MX	144	extern struct kmem_cache *btrfs_delayed_ref_head_cachep;
	145	extern struct kmem_cache *btrfs_delayed_tree_ref_cachep;
	146	extern struct kmem_cache *btrfs_delayed_data_ref_cachep;
	147	extern struct kmem_cache *btrfs_delayed_extent_op_cachep;
	148
	149	int btrfs_delayed_ref_init(void);
	150	void btrfs_delayed_ref_exit(void);
	151
	152	static inline struct btrfs_delayed_extent_op *
	153	btrfs_alloc_delayed_extent_op(void)
	154	{
	155	return kmem_cache_alloc(btrfs_delayed_extent_op_cachep, GFP_NOFS);
	156	}
	157
	158	static inline void
	159	btrfs_free_delayed_extent_op(struct btrfs_delayed_extent_op *op)
	160	{
	161	if (op)
	162	kmem_cache_free(btrfs_delayed_extent_op_cachep, op);
	163	}
	164
56bec294 CM	165	static inline void btrfs_put_delayed_ref(struct btrfs_delayed_ref_node *ref)
	166	{
	167	WARN_ON(atomic_read(&ref->refs) == 0);
	168	if (atomic_dec_and_test(&ref->refs)) {
	169	WARN_ON(ref->in_tree);
78a6184a MX	170	switch (ref->type) {
	171	case BTRFS_TREE_BLOCK_REF_KEY:
	172	case BTRFS_SHARED_BLOCK_REF_KEY:
	173	kmem_cache_free(btrfs_delayed_tree_ref_cachep, ref);
	174	break;
	175	case BTRFS_EXTENT_DATA_REF_KEY:
	176	case BTRFS_SHARED_DATA_REF_KEY:
	177	kmem_cache_free(btrfs_delayed_data_ref_cachep, ref);
	178	break;
	179	case 0:
	180	kmem_cache_free(btrfs_delayed_ref_head_cachep, ref);
	181	break;
	182	default:
	183	BUG();
	184	}
56bec294 CM	185	}
	186	}
	187
66d7e7f0 AJ	188	int btrfs_add_delayed_tree_ref(struct btrfs_fs_info *fs_info,
66d7e7f0 AJ	189	struct btrfs_trans_handle *trans,
5d4f98a2 YZ	190	u64 bytenr, u64 num_bytes, u64 parent,
5d4f98a2 YZ	191	u64 ref_root, int level, int action,
66d7e7f0 AJ	192	struct btrfs_delayed_extent_op *extent_op,
	193	int for_cow);
	194	int btrfs_add_delayed_data_ref(struct btrfs_fs_info *fs_info,
	195	struct btrfs_trans_handle *trans,
5d4f98a2 YZ	196	u64 bytenr, u64 num_bytes,
	197	u64 parent, u64 ref_root,
	198	u64 owner, u64 offset, int action,
66d7e7f0 AJ	199	struct btrfs_delayed_extent_op *extent_op,
	200	int for_cow);
	201	int btrfs_add_delayed_extent_op(struct btrfs_fs_info *fs_info,
	202	struct btrfs_trans_handle *trans,
5d4f98a2 YZ	203	u64 bytenr, u64 num_bytes,
5d4f98a2 YZ	204	struct btrfs_delayed_extent_op *extent_op);
ae1e206b JB	205	void btrfs_merge_delayed_refs(struct btrfs_trans_handle *trans,
	206	struct btrfs_fs_info *fs_info,
	207	struct btrfs_delayed_ref_root *delayed_refs,
	208	struct btrfs_delayed_ref_head *head);
56bec294	209
1887be66 CM	210	struct btrfs_delayed_ref_head *
1887be66 CM	211	btrfs_find_delayed_ref_head(struct btrfs_trans_handle *trans, u64 bytenr);
c3e69d58 CM	212	int btrfs_delayed_ref_lock(struct btrfs_trans_handle *trans,
	213	struct btrfs_delayed_ref_head *head);
	214	int btrfs_find_ref_cluster(struct btrfs_trans_handle *trans,
	215	struct list_head *cluster, u64 search_start);
00f04b88	216
097b8a7c JS	217	int btrfs_check_delayed_seq(struct btrfs_fs_info *fs_info,
097b8a7c JS	218	struct btrfs_delayed_ref_root *delayed_refs,
00f04b88 AJ	219	u64 seq);
00f04b88 AJ	220
546adb0d JS	221	/*
	222	* delayed refs with a ref_seq > 0 must be held back during backref walking.
	223	* this only applies to items in one of the fs-trees. for_cow items never need
	224	* to be held back, so they won't get a ref_seq number.
	225	*/
	226	static inline int need_ref_seq(int for_cow, u64 rootid)
	227	{
	228	if (for_cow)
	229	return 0;
	230
	231	if (rootid == BTRFS_FS_TREE_OBJECTID)
	232	return 1;
	233
	234	if ((s64)rootid >= (s64)BTRFS_FIRST_FREE_OBJECTID)
	235	return 1;
	236
	237	return 0;
	238	}
	239
56bec294 CM	240	/*
	241	* a node might live in a head or a regular ref, this lets you
	242	* test for the proper type to use.
	243	*/
	244	static int btrfs_delayed_ref_is_head(struct btrfs_delayed_ref_node *node)
	245	{
5d4f98a2	246	return node->is_head;
56bec294 CM	247	}
	248
	249	/*
	250	* helper functions to cast a node into its container
	251	*/
5d4f98a2 YZ	252	static inline struct btrfs_delayed_tree_ref *
5d4f98a2 YZ	253	btrfs_delayed_node_to_tree_ref(struct btrfs_delayed_ref_node *node)
56bec294 CM	254	{
56bec294 CM	255	WARN_ON(btrfs_delayed_ref_is_head(node));
5d4f98a2 YZ	256	return container_of(node, struct btrfs_delayed_tree_ref, node);
5d4f98a2 YZ	257	}
56bec294	258
5d4f98a2 YZ	259	static inline struct btrfs_delayed_data_ref *
	260	btrfs_delayed_node_to_data_ref(struct btrfs_delayed_ref_node *node)
	261	{
	262	WARN_ON(btrfs_delayed_ref_is_head(node));
	263	return container_of(node, struct btrfs_delayed_data_ref, node);
56bec294 CM	264	}
	265
	266	static inline struct btrfs_delayed_ref_head *
	267	btrfs_delayed_node_to_head(struct btrfs_delayed_ref_node *node)
	268	{
	269	WARN_ON(!btrfs_delayed_ref_is_head(node));
	270	return container_of(node, struct btrfs_delayed_ref_head, node);
56bec294 CM	271	}
56bec294 CM	272	#endif