xref: /linux/drivers/md/raid1.h (revision e190bfe56841551b1ad5abb42ebd0c4798cc8c01)
1 #ifndef _RAID1_H
2 #define _RAID1_H
3 
4 typedef struct mirror_info mirror_info_t;
5 
6 struct mirror_info {
7 	mdk_rdev_t	*rdev;
8 	sector_t	head_position;
9 };
10 
11 /*
12  * memory pools need a pointer to the mddev, so they can force an unplug
13  * when memory is tight, and a count of the number of drives that the
14  * pool was allocated for, so they know how much to allocate and free.
15  * mddev->raid_disks cannot be used, as it can change while a pool is active
16  * These two datums are stored in a kmalloced struct.
17  */
18 
19 struct pool_info {
20 	mddev_t *mddev;
21 	int	raid_disks;
22 };
23 
24 
25 typedef struct r1bio_s r1bio_t;
26 
27 struct r1_private_data_s {
28 	mddev_t			*mddev;
29 	mirror_info_t		*mirrors;
30 	int			raid_disks;
31 	int			last_used;
32 	sector_t		next_seq_sect;
33 	spinlock_t		device_lock;
34 
35 	struct list_head	retry_list;
36 	/* queue pending writes and submit them on unplug */
37 	struct bio_list		pending_bio_list;
38 	/* queue of writes that have been unplugged */
39 	struct bio_list		flushing_bio_list;
40 
41 	/* for use when syncing mirrors: */
42 
43 	spinlock_t		resync_lock;
44 	int			nr_pending;
45 	int			nr_waiting;
46 	int			nr_queued;
47 	int			barrier;
48 	sector_t		next_resync;
49 	int			fullsync;  /* set to 1 if a full sync is needed,
50 					    * (fresh device added).
51 					    * Cleared when a sync completes.
52 					    */
53 
54 	wait_queue_head_t	wait_barrier;
55 
56 	struct pool_info	*poolinfo;
57 
58 	struct page		*tmppage;
59 
60 	mempool_t *r1bio_pool;
61 	mempool_t *r1buf_pool;
62 
63 	/* When taking over an array from a different personality, we store
64 	 * the new thread here until we fully activate the array.
65 	 */
66 	struct mdk_thread_s	*thread;
67 };
68 
69 typedef struct r1_private_data_s conf_t;
70 
71 /*
72  * this is our 'private' RAID1 bio.
73  *
74  * it contains information about what kind of IO operations were started
75  * for this RAID1 operation, and about their status:
76  */
77 
78 struct r1bio_s {
79 	atomic_t		remaining; /* 'have we finished' count,
80 					    * used from IRQ handlers
81 					    */
82 	atomic_t		behind_remaining; /* number of write-behind ios remaining
83 						 * in this BehindIO request
84 						 */
85 	sector_t		sector;
86 	int			sectors;
87 	unsigned long		state;
88 	mddev_t			*mddev;
89 	/*
90 	 * original bio going to /dev/mdx
91 	 */
92 	struct bio		*master_bio;
93 	/*
94 	 * if the IO is in READ direction, then this is where we read
95 	 */
96 	int			read_disk;
97 
98 	struct list_head	retry_list;
99 	struct bitmap_update	*bitmap_update;
100 	/*
101 	 * if the IO is in WRITE direction, then multiple bios are used.
102 	 * We choose the number when they are allocated.
103 	 */
104 	struct bio		*bios[0];
105 	/* DO NOT PUT ANY NEW FIELDS HERE - bios array is contiguously alloced*/
106 };
107 
108 /* when we get a read error on a read-only array, we redirect to another
109  * device without failing the first device, or trying to over-write to
110  * correct the read error.  To keep track of bad blocks on a per-bio
111  * level, we store IO_BLOCKED in the appropriate 'bios' pointer
112  */
113 #define IO_BLOCKED ((struct bio*)1)
114 
115 /* bits for r1bio.state */
116 #define	R1BIO_Uptodate	0
117 #define	R1BIO_IsSync	1
118 #define	R1BIO_Degraded	2
119 #define	R1BIO_BehindIO	3
120 #define	R1BIO_Barrier	4
121 #define R1BIO_BarrierRetry 5
122 /* For write-behind requests, we call bi_end_io when
123  * the last non-write-behind device completes, providing
124  * any write was successful.  Otherwise we call when
125  * any write-behind write succeeds, otherwise we call
126  * with failure when last write completes (and all failed).
127  * Record that bi_end_io was called with this flag...
128  */
129 #define	R1BIO_Returned 6
130 
131 #endif
132