[mirror_ubuntu-hirsute-kernel.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->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;

	/*
	 * seq number of delayed refs. We need to know if a backref was being
	 * added before the currently processed ref or afterwards.
	 */
	u64 seq;

	/*
	 * seq_list holds a list of all seq numbers that are currently being
	 * added to the list. While walking backrefs (btrfs_find_all_roots,
	 * qgroups), which might take some time, no newer ref must be processed,
	 * as it might influence the outcome of the walk.
	 */
	struct list_head seq_head;

	/*
	 * when the only refs we have in the list must not be processed, we want
	 * to wait for more refs to show up or for the end of backref walking.
	 */
	wait_queue_head_t seq_wait;
};

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);
		kfree(ref);
	}
}

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);

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);

static inline u64 inc_delayed_seq(struct btrfs_delayed_ref_root *delayed_refs)
{
	assert_spin_locked(&delayed_refs->lock);
	++delayed_refs->seq;
	return delayed_refs->seq;
}

static inline void
btrfs_get_delayed_seq(struct btrfs_delayed_ref_root *delayed_refs,
		      struct seq_list *elem)
{
	assert_spin_locked(&delayed_refs->lock);
	elem->seq = delayed_refs->seq;
	list_add_tail(&elem->list, &delayed_refs->seq_head);
}

static inline void
btrfs_put_delayed_seq(struct btrfs_delayed_ref_root *delayed_refs,
		      struct seq_list *elem)
{
	spin_lock(&delayed_refs->lock);
	list_del(&elem->list);
	wake_up(&delayed_refs->seq_wait);
	spin_unlock(&delayed_refs->lock);
}

int btrfs_check_delayed_seq(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
	21	/* these are the possible values of struct btrfs_delayed_ref->action */
	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;
00f04b88 AJ	142
	143	/*
	144	* seq number of delayed refs. We need to know if a backref was being
	145	* added before the currently processed ref or afterwards.
	146	*/
	147	u64 seq;
	148
	149	/*
	150	* seq_list holds a list of all seq numbers that are currently being
	151	* added to the list. While walking backrefs (btrfs_find_all_roots,
	152	* qgroups), which might take some time, no newer ref must be processed,
	153	* as it might influence the outcome of the walk.
	154	*/
	155	struct list_head seq_head;
a168650c JS	156
	157	/*
	158	* when the only refs we have in the list must not be processed, we want
	159	* to wait for more refs to show up or for the end of backref walking.
	160	*/
	161	wait_queue_head_t seq_wait;
56bec294 CM	162	};
	163
	164	static inline void btrfs_put_delayed_ref(struct btrfs_delayed_ref_node *ref)
	165	{
	166	WARN_ON(atomic_read(&ref->refs) == 0);
	167	if (atomic_dec_and_test(&ref->refs)) {
	168	WARN_ON(ref->in_tree);
	169	kfree(ref);
	170	}
	171	}
	172
66d7e7f0 AJ	173	int btrfs_add_delayed_tree_ref(struct btrfs_fs_info *fs_info,
66d7e7f0 AJ	174	struct btrfs_trans_handle *trans,
5d4f98a2 YZ	175	u64 bytenr, u64 num_bytes, u64 parent,
5d4f98a2 YZ	176	u64 ref_root, int level, int action,
66d7e7f0 AJ	177	struct btrfs_delayed_extent_op *extent_op,
	178	int for_cow);
	179	int btrfs_add_delayed_data_ref(struct btrfs_fs_info *fs_info,
	180	struct btrfs_trans_handle *trans,
5d4f98a2 YZ	181	u64 bytenr, u64 num_bytes,
	182	u64 parent, u64 ref_root,
	183	u64 owner, u64 offset, int action,
66d7e7f0 AJ	184	struct btrfs_delayed_extent_op *extent_op,
	185	int for_cow);
	186	int btrfs_add_delayed_extent_op(struct btrfs_fs_info *fs_info,
	187	struct btrfs_trans_handle *trans,
5d4f98a2 YZ	188	u64 bytenr, u64 num_bytes,
5d4f98a2 YZ	189	struct btrfs_delayed_extent_op *extent_op);
56bec294	190
1887be66 CM	191	struct btrfs_delayed_ref_head *
1887be66 CM	192	btrfs_find_delayed_ref_head(struct btrfs_trans_handle *trans, u64 bytenr);
c3e69d58 CM	193	int btrfs_delayed_ref_lock(struct btrfs_trans_handle *trans,
	194	struct btrfs_delayed_ref_head *head);
	195	int btrfs_find_ref_cluster(struct btrfs_trans_handle *trans,
	196	struct list_head *cluster, u64 search_start);
00f04b88	197
00f04b88 AJ	198	static inline u64 inc_delayed_seq(struct btrfs_delayed_ref_root *delayed_refs)
	199	{
	200	assert_spin_locked(&delayed_refs->lock);
	201	++delayed_refs->seq;
	202	return delayed_refs->seq;
	203	}
	204
	205	static inline void
	206	btrfs_get_delayed_seq(struct btrfs_delayed_ref_root *delayed_refs,
	207	struct seq_list *elem)
	208	{
	209	assert_spin_locked(&delayed_refs->lock);
	210	elem->seq = delayed_refs->seq;
	211	list_add_tail(&elem->list, &delayed_refs->seq_head);
	212	}
	213
	214	static inline void
	215	btrfs_put_delayed_seq(struct btrfs_delayed_ref_root *delayed_refs,
	216	struct seq_list *elem)
	217	{
	218	spin_lock(&delayed_refs->lock);
	219	list_del(&elem->list);
a168650c	220	wake_up(&delayed_refs->seq_wait);
00f04b88 AJ	221	spin_unlock(&delayed_refs->lock);
	222	}
	223
	224	int btrfs_check_delayed_seq(struct btrfs_delayed_ref_root *delayed_refs,
	225	u64 seq);
	226
56bec294 CM	227	/*
	228	* a node might live in a head or a regular ref, this lets you
	229	* test for the proper type to use.
	230	*/
	231	static int btrfs_delayed_ref_is_head(struct btrfs_delayed_ref_node *node)
	232	{
5d4f98a2	233	return node->is_head;
56bec294 CM	234	}
	235
	236	/*
	237	* helper functions to cast a node into its container
	238	*/
5d4f98a2 YZ	239	static inline struct btrfs_delayed_tree_ref *
5d4f98a2 YZ	240	btrfs_delayed_node_to_tree_ref(struct btrfs_delayed_ref_node *node)
56bec294 CM	241	{
56bec294 CM	242	WARN_ON(btrfs_delayed_ref_is_head(node));
5d4f98a2 YZ	243	return container_of(node, struct btrfs_delayed_tree_ref, node);
5d4f98a2 YZ	244	}
56bec294	245
5d4f98a2 YZ	246	static inline struct btrfs_delayed_data_ref *
	247	btrfs_delayed_node_to_data_ref(struct btrfs_delayed_ref_node *node)
	248	{
	249	WARN_ON(btrfs_delayed_ref_is_head(node));
	250	return container_of(node, struct btrfs_delayed_data_ref, node);
56bec294 CM	251	}
	252
	253	static inline struct btrfs_delayed_ref_head *
	254	btrfs_delayed_node_to_head(struct btrfs_delayed_ref_node *node)
	255	{
	256	WARN_ON(!btrfs_delayed_ref_is_head(node));
	257	return container_of(node, struct btrfs_delayed_ref_head, node);
56bec294 CM	258	}
56bec294 CM	259	#endif