[mirror_ubuntu-zesty-kernel.git] / drivers / md / raid1.h

#ifndef _RAID1_H
#define _RAID1_H

struct raid1_info {
	struct md_rdev	*rdev;
	sector_t	head_position;

	/* When choose the best device for a read (read_balance())
	 * we try to keep sequential reads one the same device
	 */
	sector_t	next_seq_sect;
	sector_t	seq_start;
};

/*
 * memory pools need a pointer to the mddev, so they can force an unplug
 * when memory is tight, and a count of the number of drives that the
 * pool was allocated for, so they know how much to allocate and free.
 * mddev->raid_disks cannot be used, as it can change while a pool is active
 * These two datums are stored in a kmalloced struct.
 * The 'raid_disks' here is twice the raid_disks in r1conf.
 * This allows space for each 'real' device can have a replacement in the
 * second half of the array.
 */

struct pool_info {
	struct mddev *mddev;
	int	raid_disks;
};

struct r1conf {
	struct mddev		*mddev;
	struct raid1_info	*mirrors;	/* twice 'raid_disks' to
						 * allow for replacements.
						 */
	int			raid_disks;

	/* During resync, read_balancing is only allowed on the part
	 * of the array that has been resynced.  'next_resync' tells us
	 * where that is.
	 */
	sector_t		next_resync;

	spinlock_t		device_lock;

	/* list of 'struct r1bio' that need to be processed by raid1d,
	 * whether to retry a read, writeout a resync or recovery
	 * block, or anything else.
	 */
	struct list_head	retry_list;

	/* queue pending writes to be submitted on unplug */
	struct bio_list		pending_bio_list;
	int			pending_count;

	/* for use when syncing mirrors:
	 * We don't allow both normal IO and resync/recovery IO at
	 * the same time - resync/recovery can only happen when there
	 * is no other IO.  So when either is active, the other has to wait.
	 * See more details description in raid1.c near raise_barrier().
	 */
	wait_queue_head_t	wait_barrier;
	spinlock_t		resync_lock;
	int			nr_pending;
	int			nr_waiting;
	int			nr_queued;
	int			barrier;
	int			array_frozen;

	/* Set to 1 if a full sync is needed, (fresh device added).
	 * Cleared when a sync completes.
	 */
	int			fullsync;

	/* When the same as mddev->recovery_disabled we don't allow
	 * recovery to be attempted as we expect a read error.
	 */
	int			recovery_disabled;


	/* poolinfo contains information about the content of the
	 * mempools - it changes when the array grows or shrinks
	 */
	struct pool_info	*poolinfo;
	mempool_t		*r1bio_pool;
	mempool_t		*r1buf_pool;

	/* temporary buffer to synchronous IO when attempting to repair
	 * a read error.
	 */
	struct page		*tmppage;


	/* When taking over an array from a different personality, we store
	 * the new thread here until we fully activate the array.
	 */
	struct md_thread	*thread;
};

/*
 * this is our 'private' RAID1 bio.
 *
 * it contains information about what kind of IO operations were started
 * for this RAID1 operation, and about their status:
 */

struct r1bio {
	atomic_t		remaining; /* 'have we finished' count,
					    * used from IRQ handlers
					    */
	atomic_t		behind_remaining; /* number of write-behind ios remaining
						 * in this BehindIO request
						 */
	sector_t		sector;
	int			sectors;
	unsigned long		state;
	struct mddev		*mddev;
	/*
	 * original bio going to /dev/mdx
	 */
	struct bio		*master_bio;
	/*
	 * if the IO is in READ direction, then this is where we read
	 */
	int			read_disk;

	struct list_head	retry_list;
	/* Next two are only valid when R1BIO_BehindIO is set */
	struct bio_vec		*behind_bvecs;
	int			behind_page_count;
	/*
	 * if the IO is in WRITE direction, then multiple bios are used.
	 * We choose the number when they are allocated.
	 */
	struct bio		*bios[0];
	/* DO NOT PUT ANY NEW FIELDS HERE - bios array is contiguously alloced*/
};

/* bits for r1bio.state */
#define	R1BIO_Uptodate	0
#define	R1BIO_IsSync	1
#define	R1BIO_Degraded	2
#define	R1BIO_BehindIO	3
/* Set ReadError on bios that experience a readerror so that
 * raid1d knows what to do with them.
 */
#define R1BIO_ReadError 4
/* For write-behind requests, we call bi_end_io when
 * the last non-write-behind device completes, providing
 * any write was successful.  Otherwise we call when
 * any write-behind write succeeds, otherwise we call
 * with failure when last write completes (and all failed).
 * Record that bi_end_io was called with this flag...
 */
#define	R1BIO_Returned 6
/* If a write for this request means we can clear some
 * known-bad-block records, we set this flag
 */
#define	R1BIO_MadeGood 7
#define	R1BIO_WriteError 8

extern int md_raid1_congested(struct mddev *mddev, int bits);

#endif
Commit	Line	Data
1da177e4 LT	1	#ifndef _RAID1_H
	2	#define _RAID1_H
	3
0eaf822c	4	struct raid1_info {
3cb03002	5	struct md_rdev *rdev;
1da177e4	6	sector_t head_position;
be4d3280 SL	7
	8	/* When choose the best device for a read (read_balance())
	9	* we try to keep sequential reads one the same device
	10	*/
	11	sector_t next_seq_sect;
12cee5a8	12	sector_t seq_start;
1da177e4 LT	13	};
	14
	15	/*
	16	* memory pools need a pointer to the mddev, so they can force an unplug
	17	* when memory is tight, and a count of the number of drives that the
	18	* pool was allocated for, so they know how much to allocate and free.
	19	* mddev->raid_disks cannot be used, as it can change while a pool is active
	20	* These two datums are stored in a kmalloced struct.
8f19ccb2 N	21	* The 'raid_disks' here is twice the raid_disks in r1conf.
	22	* This allows space for each 'real' device can have a replacement in the
	23	* second half of the array.
1da177e4 LT	24	*/
	25
	26	struct pool_info {
fd01b88c	27	struct mddev *mddev;
1da177e4 LT	28	int raid_disks;
	29	};
	30
e8096360	31	struct r1conf {
fd01b88c	32	struct mddev *mddev;
0eaf822c	33	struct raid1_info mirrors; / twice 'raid_disks' to
8f19ccb2 N	34	* allow for replacements.
8f19ccb2 N	35	*/
1da177e4	36	int raid_disks;
ce550c20	37
ce550c20 N	38	/* During resync, read_balancing is only allowed on the part
	39	* of the array that has been resynced. 'next_resync' tells us
	40	* where that is.
	41	*/
	42	sector_t next_resync;
	43
1da177e4 LT	44	spinlock_t device_lock;
1da177e4 LT	45
9f2c9d12 N	46	/* list of 'struct r1bio' that need to be processed by raid1d,
	47	* whether to retry a read, writeout a resync or recovery
	48	* block, or anything else.
ce550c20	49	*/
1da177e4	50	struct list_head retry_list;
191ea9b2	51
ce550c20 N	52	/* queue pending writes to be submitted on unplug */
ce550c20 N	53	struct bio_list pending_bio_list;
34db0cd6	54	int pending_count;
1da177e4	55
ce550c20 N	56	/* for use when syncing mirrors:
	57	* We don't allow both normal IO and resync/recovery IO at
	58	* the same time - resync/recovery can only happen when there
	59	* is no other IO. So when either is active, the other has to wait.
	60	* See more details description in raid1.c near raise_barrier().
	61	*/
	62	wait_queue_head_t wait_barrier;
1da177e4	63	spinlock_t resync_lock;
191ea9b2	64	int nr_pending;
17999be4	65	int nr_waiting;
ddaf22ab	66	int nr_queued;
191ea9b2	67	int barrier;
b364e3d0	68	int array_frozen;
1da177e4	69
ce550c20 N	70	/* Set to 1 if a full sync is needed, (fresh device added).
	71	* Cleared when a sync completes.
	72	*/
	73	int fullsync;
1da177e4	74
ce550c20 N	75	/* When the same as mddev->recovery_disabled we don't allow
	76	* recovery to be attempted as we expect a read error.
	77	*/
	78	int recovery_disabled;
1da177e4	79
ddaf22ab	80
ce550c20 N	81	/* poolinfo contains information about the content of the
	82	* mempools - it changes when the array grows or shrinks
	83	*/
	84	struct pool_info *poolinfo;
9f2c9d12 N	85	mempool_t *r1bio_pool;
9f2c9d12 N	86	mempool_t *r1buf_pool;
709ae487	87
ce550c20 N	88	/* temporary buffer to synchronous IO when attempting to repair
	89	* a read error.
	90	*/
	91	struct page *tmppage;
	92
	93
709ae487 N	94	/* When taking over an array from a different personality, we store
	95	* the new thread here until we fully activate the array.
	96	*/
2b8bf345	97	struct md_thread *thread;
1da177e4 LT	98	};
1da177e4 LT	99
1da177e4 LT	100	/*
	101	* this is our 'private' RAID1 bio.
	102	*
	103	* it contains information about what kind of IO operations were started
	104	* for this RAID1 operation, and about their status:
	105	*/
	106
9f2c9d12	107	struct r1bio {
1da177e4 LT	108	atomic_t remaining; /* 'have we finished' count,
	109	* used from IRQ handlers
	110	*/
4b6d287f N	111	atomic_t behind_remaining; /* number of write-behind ios remaining
	112	* in this BehindIO request
	113	*/
1da177e4 LT	114	sector_t sector;
	115	int sectors;
	116	unsigned long state;
fd01b88c	117	struct mddev *mddev;
1da177e4 LT	118	/*
	119	* original bio going to /dev/mdx
	120	*/
	121	struct bio *master_bio;
	122	/*
	123	* if the IO is in READ direction, then this is where we read
	124	*/
	125	int read_disk;
	126
	127	struct list_head retry_list;
af6d7b76	128	/* Next two are only valid when R1BIO_BehindIO is set */
2ca68f5e	129	struct bio_vec *behind_bvecs;
af6d7b76	130	int behind_page_count;
1da177e4 LT	131	/*
	132	* if the IO is in WRITE direction, then multiple bios are used.
	133	* We choose the number when they are allocated.
	134	*/
	135	struct bio *bios[0];
191ea9b2	136	/* DO NOT PUT ANY NEW FIELDS HERE - bios array is contiguously alloced*/
1da177e4 LT	137	};
	138
	139	/* bits for r1bio.state */
	140	#define R1BIO_Uptodate 0
	141	#define R1BIO_IsSync 1
191ea9b2	142	#define R1BIO_Degraded 2
a9701a30	143	#define R1BIO_BehindIO 3
d2eb35ac N	144	/* Set ReadError on bios that experience a readerror so that
	145	* raid1d knows what to do with them.
	146	*/
	147	#define R1BIO_ReadError 4
4b6d287f N	148	/* For write-behind requests, we call bi_end_io when
	149	* the last non-write-behind device completes, providing
	150	* any write was successful. Otherwise we call when
	151	* any write-behind write succeeds, otherwise we call
	152	* with failure when last write completes (and all failed).
	153	* Record that bi_end_io was called with this flag...
	154	*/
9e71f9c8	155	#define R1BIO_Returned 6
4367af55 N	156	/* If a write for this request means we can clear some
	157	* known-bad-block records, we set this flag
	158	*/
cd5ff9a1 N	159	#define R1BIO_MadeGood 7
cd5ff9a1 N	160	#define R1BIO_WriteError 8
4b6d287f	161
fd01b88c	162	extern int md_raid1_congested(struct mddev *mddev, int bits);
1ed7242e	163
1da177e4	164	#endif