1#ifndef _RAID1_H
  2#define _RAID1_H
  3
  4struct mirror_info {
  5	struct md_rdev	*rdev;
  6	sector_t	head_position;
  7};
  8
  9/*
 10 * memory pools need a pointer to the mddev, so they can force an unplug
 11 * when memory is tight, and a count of the number of drives that the
 12 * pool was allocated for, so they know how much to allocate and free.
 13 * mddev->raid_disks cannot be used, as it can change while a pool is active
 14 * These two datums are stored in a kmalloced struct.
 15 * The 'raid_disks' here is twice the raid_disks in r1conf.
 16 * This allows space for each 'real' device can have a replacement in the
 17 * second half of the array.
 18 */
 19
 20struct pool_info {
 21	struct mddev *mddev;
 22	int	raid_disks;
 23};
 24
 25struct r1conf {
 26	struct mddev		*mddev;
 27	struct mirror_info	*mirrors;	/* twice 'raid_disks' to
 28						 * allow for replacements.
 29						 */
 30	int			raid_disks;
 31
 32	/* When choose the best device for a read (read_balance())
 33	 * we try to keep sequential reads one the same device
 34	 * using 'last_used' and 'next_seq_sect'
 35	 */
 36	int			last_used;
 37	sector_t		next_seq_sect;
 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
 44	spinlock_t		device_lock;
 45
 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.
 49	 */
 50	struct list_head	retry_list;
 51
 52	/* queue pending writes to be submitted on unplug */
 53	struct bio_list		pending_bio_list;
 54	int			pending_count;
 55
 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;
 63	spinlock_t		resync_lock;
 64	int			nr_pending;
 65	int			nr_waiting;
 66	int			nr_queued;
 67	int			barrier;
 68
 69	/* Set to 1 if a full sync is needed, (fresh device added).
 70	 * Cleared when a sync completes.
 71	 */
 72	int			fullsync;
 73
 74	/* When the same as mddev->recovery_disabled we don't allow
 75	 * recovery to be attempted as we expect a read error.
 76	 */
 77	int			recovery_disabled;
 78
 79
 80	/* poolinfo contains information about the content of the
 81	 * mempools - it changes when the array grows or shrinks
 82	 */
 83	struct pool_info	*poolinfo;
 84	mempool_t		*r1bio_pool;
 85	mempool_t		*r1buf_pool;
 86
 87	/* temporary buffer to synchronous IO when attempting to repair
 88	 * a read error.
 89	 */
 90	struct page		*tmppage;
 91
 92
 93	/* When taking over an array from a different personality, we store
 94	 * the new thread here until we fully activate the array.
 95	 */
 96	struct md_thread	*thread;
 97};
 98
 99/*
100 * this is our 'private' RAID1 bio.
101 *
102 * it contains information about what kind of IO operations were started
103 * for this RAID1 operation, and about their status:
104 */
105
106struct r1bio {
107	atomic_t		remaining; /* 'have we finished' count,
108					    * used from IRQ handlers
109					    */
110	atomic_t		behind_remaining; /* number of write-behind ios remaining
111						 * in this BehindIO request
112						 */
113	sector_t		sector;
114	int			sectors;
115	unsigned long		state;
116	struct mddev		*mddev;
117	/*
118	 * original bio going to /dev/mdx
119	 */
120	struct bio		*master_bio;
121	/*
122	 * if the IO is in READ direction, then this is where we read
123	 */
124	int			read_disk;
125
126	struct list_head	retry_list;
127	/* Next two are only valid when R1BIO_BehindIO is set */
128	struct bio_vec		*behind_bvecs;
129	int			behind_page_count;
130	/*
131	 * if the IO is in WRITE direction, then multiple bios are used.
132	 * We choose the number when they are allocated.
133	 */
134	struct bio		*bios[0];
135	/* DO NOT PUT ANY NEW FIELDS HERE - bios array is contiguously alloced*/
136};
137
138/* when we get a read error on a read-only array, we redirect to another
139 * device without failing the first device, or trying to over-write to
140 * correct the read error.  To keep track of bad blocks on a per-bio
141 * level, we store IO_BLOCKED in the appropriate 'bios' pointer
142 */
143#define IO_BLOCKED ((struct bio *)1)
144/* When we successfully write to a known bad-block, we need to remove the
145 * bad-block marking which must be done from process context.  So we record
146 * the success by setting bios[n] to IO_MADE_GOOD
147 */
148#define IO_MADE_GOOD ((struct bio *)2)
149
150#define BIO_SPECIAL(bio) ((unsigned long)bio <= 2)
151
152/* bits for r1bio.state */
153#define	R1BIO_Uptodate	0
154#define	R1BIO_IsSync	1
155#define	R1BIO_Degraded	2
156#define	R1BIO_BehindIO	3
157/* Set ReadError on bios that experience a readerror so that
158 * raid1d knows what to do with them.
159 */
160#define R1BIO_ReadError 4
161/* For write-behind requests, we call bi_end_io when
162 * the last non-write-behind device completes, providing
163 * any write was successful.  Otherwise we call when
164 * any write-behind write succeeds, otherwise we call
165 * with failure when last write completes (and all failed).
166 * Record that bi_end_io was called with this flag...
167 */
168#define	R1BIO_Returned 6
169/* If a write for this request means we can clear some
170 * known-bad-block records, we set this flag
171 */
172#define	R1BIO_MadeGood 7
173#define	R1BIO_WriteError 8
174
175extern int md_raid1_congested(struct mddev *mddev, int bits);
176
177#endif