[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;
	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 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);
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);

/*
 * 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;
b1c79e09	63	int level;
5d4f98a2 YZ	64	unsigned int update_key:1;
	65	unsigned int update_flags:1;
	66	unsigned int is_data:1;
	67	};
	68
56bec294 CM	69	/*
	70	* the head refs are used to hold a lock on a given extent, which allows us
	71	* to make sure that only one process is running the delayed refs
	72	* at a time for a single extent. They also store the sum of all the
	73	* reference count modifications we've queued up.
	74	*/
	75	struct btrfs_delayed_ref_head {
	76	struct btrfs_delayed_ref_node node;
	77
	78	/*
	79	* the mutex is held while running the refs, and it is also
	80	* held when checking the sum of reference modifications.
	81	*/
	82	struct mutex mutex;
	83
d7df2c79 JB	84	spinlock_t lock;
d7df2c79 JB	85	struct rb_root ref_root;
c3e69d58	86
c46effa6 LB	87	struct rb_node href_node;
c46effa6 LB	88
5d4f98a2	89	struct btrfs_delayed_extent_op *extent_op;
56bec294 CM	90	/*
	91	* when a new extent is allocated, it is just reserved in memory
	92	* The actual extent isn't inserted into the extent allocation tree
	93	* until the delayed ref is processed. must_insert_reserved is
	94	* used to flag a delayed ref so the accounting can be updated
	95	* when a full insert is done.
	96	*
	97	* It is possible the extent will be freed before it is ever
	98	* inserted into the extent allocation tree. In this case
	99	* we need to update the in ram accounting to properly reflect
	100	* the free has happened.
	101	*/
	102	unsigned int must_insert_reserved:1;
5d4f98a2	103	unsigned int is_data:1;
d7df2c79	104	unsigned int processing:1;
56bec294 CM	105	};
56bec294 CM	106
5d4f98a2	107	struct btrfs_delayed_tree_ref {
56bec294	108	struct btrfs_delayed_ref_node node;
eebe063b AJ	109	u64 root;
eebe063b AJ	110	u64 parent;
5d4f98a2 YZ	111	int level;
5d4f98a2 YZ	112	};
56bec294	113
5d4f98a2 YZ	114	struct btrfs_delayed_data_ref {
5d4f98a2 YZ	115	struct btrfs_delayed_ref_node node;
eebe063b AJ	116	u64 root;
eebe063b AJ	117	u64 parent;
5d4f98a2 YZ	118	u64 objectid;
5d4f98a2 YZ	119	u64 offset;
56bec294 CM	120	};
	121
	122	struct btrfs_delayed_ref_root {
c46effa6 LB	123	/* head ref rbtree */
	124	struct rb_root href_root;
	125
56bec294 CM	126	/* this spin lock protects the rbtree and the entries inside */
	127	spinlock_t lock;
	128
	129	/* how many delayed ref updates we've queued, used by the
	130	* throttling code
	131	*/
d7df2c79	132	atomic_t num_entries;
56bec294	133
c3e69d58 CM	134	/* total number of head nodes in tree */
	135	unsigned long num_heads;
	136
	137	/* total number of head nodes ready for processing */
	138	unsigned long num_heads_ready;
	139
56bec294 CM	140	/*
	141	* set when the tree is flushing before a transaction commit,
	142	* used by the throttling code to decide if new updates need
	143	* to be run right away
	144	*/
	145	int flushing;
c3e69d58 CM	146
c3e69d58 CM	147	u64 run_delayed_start;
56bec294 CM	148	};
56bec294 CM	149
78a6184a MX	150	extern struct kmem_cache *btrfs_delayed_ref_head_cachep;
	151	extern struct kmem_cache *btrfs_delayed_tree_ref_cachep;
	152	extern struct kmem_cache *btrfs_delayed_data_ref_cachep;
	153	extern struct kmem_cache *btrfs_delayed_extent_op_cachep;
	154
	155	int btrfs_delayed_ref_init(void);
	156	void btrfs_delayed_ref_exit(void);
	157
	158	static inline struct btrfs_delayed_extent_op *
	159	btrfs_alloc_delayed_extent_op(void)
	160	{
	161	return kmem_cache_alloc(btrfs_delayed_extent_op_cachep, GFP_NOFS);
	162	}
	163
	164	static inline void
	165	btrfs_free_delayed_extent_op(struct btrfs_delayed_extent_op *op)
	166	{
	167	if (op)
	168	kmem_cache_free(btrfs_delayed_extent_op_cachep, op);
	169	}
	170
56bec294 CM	171	static inline void btrfs_put_delayed_ref(struct btrfs_delayed_ref_node *ref)
	172	{
	173	WARN_ON(atomic_read(&ref->refs) == 0);
	174	if (atomic_dec_and_test(&ref->refs)) {
	175	WARN_ON(ref->in_tree);
78a6184a MX	176	switch (ref->type) {
	177	case BTRFS_TREE_BLOCK_REF_KEY:
	178	case BTRFS_SHARED_BLOCK_REF_KEY:
	179	kmem_cache_free(btrfs_delayed_tree_ref_cachep, ref);
	180	break;
	181	case BTRFS_EXTENT_DATA_REF_KEY:
	182	case BTRFS_SHARED_DATA_REF_KEY:
	183	kmem_cache_free(btrfs_delayed_data_ref_cachep, ref);
	184	break;
	185	case 0:
	186	kmem_cache_free(btrfs_delayed_ref_head_cachep, ref);
	187	break;
	188	default:
	189	BUG();
	190	}
56bec294 CM	191	}
	192	}
	193
66d7e7f0 AJ	194	int btrfs_add_delayed_tree_ref(struct btrfs_fs_info *fs_info,
66d7e7f0 AJ	195	struct btrfs_trans_handle *trans,
5d4f98a2 YZ	196	u64 bytenr, u64 num_bytes, u64 parent,
5d4f98a2 YZ	197	u64 ref_root, int level, int action,
66d7e7f0 AJ	198	struct btrfs_delayed_extent_op *extent_op,
	199	int for_cow);
	200	int btrfs_add_delayed_data_ref(struct btrfs_fs_info *fs_info,
	201	struct btrfs_trans_handle *trans,
5d4f98a2 YZ	202	u64 bytenr, u64 num_bytes,
	203	u64 parent, u64 ref_root,
	204	u64 owner, u64 offset, int action,
66d7e7f0 AJ	205	struct btrfs_delayed_extent_op *extent_op,
	206	int for_cow);
	207	int btrfs_add_delayed_extent_op(struct btrfs_fs_info *fs_info,
	208	struct btrfs_trans_handle *trans,
5d4f98a2 YZ	209	u64 bytenr, u64 num_bytes,
5d4f98a2 YZ	210	struct btrfs_delayed_extent_op *extent_op);
ae1e206b JB	211	void btrfs_merge_delayed_refs(struct btrfs_trans_handle *trans,
	212	struct btrfs_fs_info *fs_info,
	213	struct btrfs_delayed_ref_root *delayed_refs,
	214	struct btrfs_delayed_ref_head *head);
56bec294	215
1887be66 CM	216	struct btrfs_delayed_ref_head *
1887be66 CM	217	btrfs_find_delayed_ref_head(struct btrfs_trans_handle *trans, u64 bytenr);
c3e69d58 CM	218	int btrfs_delayed_ref_lock(struct btrfs_trans_handle *trans,
c3e69d58 CM	219	struct btrfs_delayed_ref_head *head);
093486c4 MX	220	static inline void btrfs_delayed_ref_unlock(struct btrfs_delayed_ref_head *head)
	221	{
	222	mutex_unlock(&head->mutex);
	223	}
	224
d7df2c79 JB	225
	226	struct btrfs_delayed_ref_head *
	227	btrfs_select_ref_head(struct btrfs_trans_handle *trans);
00f04b88	228
097b8a7c JS	229	int btrfs_check_delayed_seq(struct btrfs_fs_info *fs_info,
097b8a7c JS	230	struct btrfs_delayed_ref_root *delayed_refs,
00f04b88 AJ	231	u64 seq);
00f04b88 AJ	232
546adb0d JS	233	/*
	234	* delayed refs with a ref_seq > 0 must be held back during backref walking.
	235	* this only applies to items in one of the fs-trees. for_cow items never need
	236	* to be held back, so they won't get a ref_seq number.
	237	*/
	238	static inline int need_ref_seq(int for_cow, u64 rootid)
	239	{
	240	if (for_cow)
	241	return 0;
	242
	243	if (rootid == BTRFS_FS_TREE_OBJECTID)
	244	return 1;
	245
	246	if ((s64)rootid >= (s64)BTRFS_FIRST_FREE_OBJECTID)
	247	return 1;
	248
	249	return 0;
	250	}
	251
56bec294 CM	252	/*
	253	* a node might live in a head or a regular ref, this lets you
	254	* test for the proper type to use.
	255	*/
	256	static int btrfs_delayed_ref_is_head(struct btrfs_delayed_ref_node *node)
	257	{
5d4f98a2	258	return node->is_head;
56bec294 CM	259	}
	260
	261	/*
	262	* helper functions to cast a node into its container
	263	*/
5d4f98a2 YZ	264	static inline struct btrfs_delayed_tree_ref *
5d4f98a2 YZ	265	btrfs_delayed_node_to_tree_ref(struct btrfs_delayed_ref_node *node)
56bec294 CM	266	{
56bec294 CM	267	WARN_ON(btrfs_delayed_ref_is_head(node));
5d4f98a2 YZ	268	return container_of(node, struct btrfs_delayed_tree_ref, node);
5d4f98a2 YZ	269	}
56bec294	270
5d4f98a2 YZ	271	static inline struct btrfs_delayed_data_ref *
	272	btrfs_delayed_node_to_data_ref(struct btrfs_delayed_ref_node *node)
	273	{
	274	WARN_ON(btrfs_delayed_ref_is_head(node));
	275	return container_of(node, struct btrfs_delayed_data_ref, node);
56bec294 CM	276	}
	277
	278	static inline struct btrfs_delayed_ref_head *
	279	btrfs_delayed_node_to_head(struct btrfs_delayed_ref_node *node)
	280	{
	281	WARN_ON(!btrfs_delayed_ref_is_head(node));
	282	return container_of(node, struct btrfs_delayed_ref_head, node);
56bec294 CM	283	}
56bec294 CM	284	#endif