[linux-2.6-block.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;
	unsigned int no_quota:1;
	/* 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;
	int level;
	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;

	spinlock_t lock;
	struct rb_root ref_root;

	struct rb_node href_node;

	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;
	unsigned int processing: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 {
	/* head ref rbtree */
	struct rb_root href_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
	 */
	atomic_t 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 no_quota);
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 no_quota);
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);
static inline void btrfs_delayed_ref_unlock(struct btrfs_delayed_ref_head *head)
{
	mutex_unlock(&head->mutex);
}


struct btrfs_delayed_ref_head *
btrfs_select_ref_head(struct btrfs_trans_handle *trans);

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

/*
 * 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;
fcebe456	55	unsigned int no_quota:1;
56bec294	56	/* is this node still in the rbtree? */
5d4f98a2	57	unsigned int is_head:1;
56bec294 CM	58	unsigned int in_tree:1;
	59	};
	60
5d4f98a2 YZ	61	struct btrfs_delayed_extent_op {
	62	struct btrfs_disk_key key;
	63	u64 flags_to_set;
b1c79e09	64	int level;
5d4f98a2 YZ	65	unsigned int update_key:1;
	66	unsigned int update_flags:1;
	67	unsigned int is_data:1;
	68	};
	69
56bec294 CM	70	/*
	71	* the head refs are used to hold a lock on a given extent, which allows us
	72	* to make sure that only one process is running the delayed refs
	73	* at a time for a single extent. They also store the sum of all the
	74	* reference count modifications we've queued up.
	75	*/
	76	struct btrfs_delayed_ref_head {
	77	struct btrfs_delayed_ref_node node;
	78
	79	/*
	80	* the mutex is held while running the refs, and it is also
	81	* held when checking the sum of reference modifications.
	82	*/
	83	struct mutex mutex;
	84
d7df2c79 JB	85	spinlock_t lock;
d7df2c79 JB	86	struct rb_root ref_root;
c3e69d58	87
c46effa6 LB	88	struct rb_node href_node;
c46effa6 LB	89
5d4f98a2	90	struct btrfs_delayed_extent_op *extent_op;
56bec294 CM	91	/*
	92	* when a new extent is allocated, it is just reserved in memory
	93	* The actual extent isn't inserted into the extent allocation tree
	94	* until the delayed ref is processed. must_insert_reserved is
	95	* used to flag a delayed ref so the accounting can be updated
	96	* when a full insert is done.
	97	*
	98	* It is possible the extent will be freed before it is ever
	99	* inserted into the extent allocation tree. In this case
	100	* we need to update the in ram accounting to properly reflect
	101	* the free has happened.
	102	*/
	103	unsigned int must_insert_reserved:1;
5d4f98a2	104	unsigned int is_data:1;
d7df2c79	105	unsigned int processing:1;
56bec294 CM	106	};
56bec294 CM	107
5d4f98a2	108	struct btrfs_delayed_tree_ref {
56bec294	109	struct btrfs_delayed_ref_node node;
eebe063b AJ	110	u64 root;
eebe063b AJ	111	u64 parent;
5d4f98a2 YZ	112	int level;
5d4f98a2 YZ	113	};
56bec294	114
5d4f98a2 YZ	115	struct btrfs_delayed_data_ref {
5d4f98a2 YZ	116	struct btrfs_delayed_ref_node node;
eebe063b AJ	117	u64 root;
eebe063b AJ	118	u64 parent;
5d4f98a2 YZ	119	u64 objectid;
5d4f98a2 YZ	120	u64 offset;
56bec294 CM	121	};
	122
	123	struct btrfs_delayed_ref_root {
c46effa6 LB	124	/* head ref rbtree */
	125	struct rb_root href_root;
	126
56bec294 CM	127	/* this spin lock protects the rbtree and the entries inside */
	128	spinlock_t lock;
	129
	130	/* how many delayed ref updates we've queued, used by the
	131	* throttling code
	132	*/
d7df2c79	133	atomic_t num_entries;
56bec294	134
c3e69d58 CM	135	/* total number of head nodes in tree */
	136	unsigned long num_heads;
	137
	138	/* total number of head nodes ready for processing */
	139	unsigned long num_heads_ready;
	140
56bec294 CM	141	/*
	142	* set when the tree is flushing before a transaction commit,
	143	* used by the throttling code to decide if new updates need
	144	* to be run right away
	145	*/
	146	int flushing;
c3e69d58 CM	147
c3e69d58 CM	148	u64 run_delayed_start;
56bec294 CM	149	};
56bec294 CM	150
78a6184a MX	151	extern struct kmem_cache *btrfs_delayed_ref_head_cachep;
	152	extern struct kmem_cache *btrfs_delayed_tree_ref_cachep;
	153	extern struct kmem_cache *btrfs_delayed_data_ref_cachep;
	154	extern struct kmem_cache *btrfs_delayed_extent_op_cachep;
	155
	156	int btrfs_delayed_ref_init(void);
	157	void btrfs_delayed_ref_exit(void);
	158
	159	static inline struct btrfs_delayed_extent_op *
	160	btrfs_alloc_delayed_extent_op(void)
	161	{
	162	return kmem_cache_alloc(btrfs_delayed_extent_op_cachep, GFP_NOFS);
	163	}
	164
	165	static inline void
	166	btrfs_free_delayed_extent_op(struct btrfs_delayed_extent_op *op)
	167	{
	168	if (op)
	169	kmem_cache_free(btrfs_delayed_extent_op_cachep, op);
	170	}
	171
56bec294 CM	172	static inline void btrfs_put_delayed_ref(struct btrfs_delayed_ref_node *ref)
	173	{
	174	WARN_ON(atomic_read(&ref->refs) == 0);
	175	if (atomic_dec_and_test(&ref->refs)) {
	176	WARN_ON(ref->in_tree);
78a6184a MX	177	switch (ref->type) {
	178	case BTRFS_TREE_BLOCK_REF_KEY:
	179	case BTRFS_SHARED_BLOCK_REF_KEY:
	180	kmem_cache_free(btrfs_delayed_tree_ref_cachep, ref);
	181	break;
	182	case BTRFS_EXTENT_DATA_REF_KEY:
	183	case BTRFS_SHARED_DATA_REF_KEY:
	184	kmem_cache_free(btrfs_delayed_data_ref_cachep, ref);
	185	break;
	186	case 0:
	187	kmem_cache_free(btrfs_delayed_ref_head_cachep, ref);
	188	break;
	189	default:
	190	BUG();
	191	}
56bec294 CM	192	}
	193	}
	194
66d7e7f0 AJ	195	int btrfs_add_delayed_tree_ref(struct btrfs_fs_info *fs_info,
66d7e7f0 AJ	196	struct btrfs_trans_handle *trans,
5d4f98a2 YZ	197	u64 bytenr, u64 num_bytes, u64 parent,
5d4f98a2 YZ	198	u64 ref_root, int level, int action,
66d7e7f0	199	struct btrfs_delayed_extent_op *extent_op,
fcebe456	200	int no_quota);
66d7e7f0 AJ	201	int btrfs_add_delayed_data_ref(struct btrfs_fs_info *fs_info,
66d7e7f0 AJ	202	struct btrfs_trans_handle *trans,
5d4f98a2 YZ	203	u64 bytenr, u64 num_bytes,
	204	u64 parent, u64 ref_root,
	205	u64 owner, u64 offset, int action,
66d7e7f0	206	struct btrfs_delayed_extent_op *extent_op,
fcebe456	207	int no_quota);
66d7e7f0 AJ	208	int btrfs_add_delayed_extent_op(struct btrfs_fs_info *fs_info,
66d7e7f0 AJ	209	struct btrfs_trans_handle *trans,
5d4f98a2 YZ	210	u64 bytenr, u64 num_bytes,
5d4f98a2 YZ	211	struct btrfs_delayed_extent_op *extent_op);
ae1e206b JB	212	void btrfs_merge_delayed_refs(struct btrfs_trans_handle *trans,
	213	struct btrfs_fs_info *fs_info,
	214	struct btrfs_delayed_ref_root *delayed_refs,
	215	struct btrfs_delayed_ref_head *head);
56bec294	216
1887be66 CM	217	struct btrfs_delayed_ref_head *
1887be66 CM	218	btrfs_find_delayed_ref_head(struct btrfs_trans_handle *trans, u64 bytenr);
c3e69d58 CM	219	int btrfs_delayed_ref_lock(struct btrfs_trans_handle *trans,
c3e69d58 CM	220	struct btrfs_delayed_ref_head *head);
093486c4 MX	221	static inline void btrfs_delayed_ref_unlock(struct btrfs_delayed_ref_head *head)
	222	{
	223	mutex_unlock(&head->mutex);
	224	}
	225
d7df2c79 JB	226
	227	struct btrfs_delayed_ref_head *
	228	btrfs_select_ref_head(struct btrfs_trans_handle *trans);
00f04b88	229
097b8a7c JS	230	int btrfs_check_delayed_seq(struct btrfs_fs_info *fs_info,
097b8a7c JS	231	struct btrfs_delayed_ref_root *delayed_refs,
00f04b88 AJ	232	u64 seq);
00f04b88 AJ	233
56bec294 CM	234	/*
	235	* a node might live in a head or a regular ref, this lets you
	236	* test for the proper type to use.
	237	*/
	238	static int btrfs_delayed_ref_is_head(struct btrfs_delayed_ref_node *node)
	239	{
5d4f98a2	240	return node->is_head;
56bec294 CM	241	}
	242
	243	/*
	244	* helper functions to cast a node into its container
	245	*/
5d4f98a2 YZ	246	static inline struct btrfs_delayed_tree_ref *
5d4f98a2 YZ	247	btrfs_delayed_node_to_tree_ref(struct btrfs_delayed_ref_node *node)
56bec294 CM	248	{
56bec294 CM	249	WARN_ON(btrfs_delayed_ref_is_head(node));
5d4f98a2 YZ	250	return container_of(node, struct btrfs_delayed_tree_ref, node);
5d4f98a2 YZ	251	}
56bec294	252
5d4f98a2 YZ	253	static inline struct btrfs_delayed_data_ref *
	254	btrfs_delayed_node_to_data_ref(struct btrfs_delayed_ref_node *node)
	255	{
	256	WARN_ON(btrfs_delayed_ref_is_head(node));
	257	return container_of(node, struct btrfs_delayed_data_ref, node);
56bec294 CM	258	}
	259
	260	static inline struct btrfs_delayed_ref_head *
	261	btrfs_delayed_node_to_head(struct btrfs_delayed_ref_node *node)
	262	{
	263	WARN_ON(!btrfs_delayed_ref_is_head(node));
	264	return container_of(node, struct btrfs_delayed_ref_head, node);
56bec294 CM	265	}
56bec294 CM	266	#endif