xref: /linux/drivers/md/raid10.h (revision e0bf6c5ca2d3281f231c5f0c9bf145e9513644de)
1 #ifndef _RAID10_H
2 #define _RAID10_H
3 
4 struct raid10_info {
5 	struct md_rdev	*rdev, *replacement;
6 	sector_t	head_position;
7 	int		recovery_disabled;	/* matches
8 						 * mddev->recovery_disabled
9 						 * when we shouldn't try
10 						 * recovering this device.
11 						 */
12 };
13 
14 struct r10conf {
15 	struct mddev		*mddev;
16 	struct raid10_info	*mirrors;
17 	struct raid10_info	*mirrors_new, *mirrors_old;
18 	spinlock_t		device_lock;
19 
20 	/* geometry */
21 	struct geom {
22 		int		raid_disks;
23 		int		near_copies;  /* number of copies laid out
24 					       * raid0 style */
25 		int		far_copies;   /* number of copies laid out
26 					       * at large strides across drives
27 					       */
28 		int		far_offset;   /* far_copies are offset by 1
29 					       * stripe instead of many
30 					       */
31 		sector_t	stride;	      /* distance between far copies.
32 					       * This is size / far_copies unless
33 					       * far_offset, in which case it is
34 					       * 1 stripe.
35 					       */
36 		int             far_set_size; /* The number of devices in a set,
37 					       * where a 'set' are devices that
38 					       * contain far/offset copies of
39 					       * each other.
40 					       */
41 		int		chunk_shift; /* shift from chunks to sectors */
42 		sector_t	chunk_mask;
43 	} prev, geo;
44 	int			copies;	      /* near_copies * far_copies.
45 					       * must be <= raid_disks
46 					       */
47 
48 	sector_t		dev_sectors;  /* temp copy of
49 					       * mddev->dev_sectors */
50 	sector_t		reshape_progress;
51 	sector_t		reshape_safe;
52 	unsigned long		reshape_checkpoint;
53 	sector_t		offset_diff;
54 
55 	struct list_head	retry_list;
56 	/* queue pending writes and submit them on unplug */
57 	struct bio_list		pending_bio_list;
58 	int			pending_count;
59 
60 	spinlock_t		resync_lock;
61 	int			nr_pending;
62 	int			nr_waiting;
63 	int			nr_queued;
64 	int			barrier;
65 	sector_t		next_resync;
66 	int			fullsync;  /* set to 1 if a full sync is needed,
67 					    * (fresh device added).
68 					    * Cleared when a sync completes.
69 					    */
70 	int			have_replacement; /* There is at least one
71 						   * replacement device.
72 						   */
73 	wait_queue_head_t	wait_barrier;
74 
75 	mempool_t		*r10bio_pool;
76 	mempool_t		*r10buf_pool;
77 	struct page		*tmppage;
78 
79 	/* When taking over an array from a different personality, we store
80 	 * the new thread here until we fully activate the array.
81 	 */
82 	struct md_thread	*thread;
83 };
84 
85 /*
86  * this is our 'private' RAID10 bio.
87  *
88  * it contains information about what kind of IO operations were started
89  * for this RAID10 operation, and about their status:
90  */
91 
92 struct r10bio {
93 	atomic_t		remaining; /* 'have we finished' count,
94 					    * used from IRQ handlers
95 					    */
96 	sector_t		sector;	/* virtual sector number */
97 	int			sectors;
98 	unsigned long		state;
99 	struct mddev		*mddev;
100 	/*
101 	 * original bio going to /dev/mdx
102 	 */
103 	struct bio		*master_bio;
104 	/*
105 	 * if the IO is in READ direction, then this is where we read
106 	 */
107 	int			read_slot;
108 
109 	struct list_head	retry_list;
110 	/*
111 	 * if the IO is in WRITE direction, then multiple bios are used,
112 	 * one for each copy.
113 	 * When resyncing we also use one for each copy.
114 	 * When reconstructing, we use 2 bios, one for read, one for write.
115 	 * We choose the number when they are allocated.
116 	 * We sometimes need an extra bio to write to the replacement.
117 	 */
118 	struct r10dev {
119 		struct bio	*bio;
120 		union {
121 			struct bio	*repl_bio; /* used for resync and
122 						    * writes */
123 			struct md_rdev	*rdev;	   /* used for reads
124 						    * (read_slot >= 0) */
125 		};
126 		sector_t	addr;
127 		int		devnum;
128 	} devs[0];
129 };
130 
131 /* bits for r10bio.state */
132 enum r10bio_state {
133 	R10BIO_Uptodate,
134 	R10BIO_IsSync,
135 	R10BIO_IsRecover,
136 	R10BIO_IsReshape,
137 	R10BIO_Degraded,
138 /* Set ReadError on bios that experience a read error
139  * so that raid10d knows what to do with them.
140  */
141 	R10BIO_ReadError,
142 /* If a write for this request means we can clear some
143  * known-bad-block records, we set this flag.
144  */
145 	R10BIO_MadeGood,
146 	R10BIO_WriteError,
147 /* During a reshape we might be performing IO on the
148  * 'previous' part of the array, in which case this
149  * flag is set
150  */
151 	R10BIO_Previous,
152 };
153 #endif
154