Linux 3.4.102
[linux/fpc-iii.git] / drivers / md / raid1.h
blob80ded139314cf8a649729ce8e22915ca11bbd17f
1 #ifndef _RAID1_H
2 #define _RAID1_H
4 struct mirror_info {
5 struct md_rdev *rdev;
6 sector_t head_position;
7 };
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.
20 struct pool_info {
21 struct mddev *mddev;
22 int raid_disks;
25 struct r1conf {
26 struct mddev *mddev;
27 struct mirror_info *mirrors; /* twice 'raid_disks' to
28 * allow for replacements.
30 int raid_disks;
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'
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.
42 sector_t next_resync;
44 spinlock_t device_lock;
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.
50 struct list_head retry_list;
52 /* queue pending writes to be submitted on unplug */
53 struct bio_list pending_bio_list;
54 int pending_count;
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().
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;
69 /* Set to 1 if a full sync is needed, (fresh device added).
70 * Cleared when a sync completes.
72 int fullsync;
74 /* When the same as mddev->recovery_disabled we don't allow
75 * recovery to be attempted as we expect a read error.
77 int recovery_disabled;
80 /* poolinfo contains information about the content of the
81 * mempools - it changes when the array grows or shrinks
83 struct pool_info *poolinfo;
84 mempool_t *r1bio_pool;
85 mempool_t *r1buf_pool;
87 /* temporary buffer to synchronous IO when attempting to repair
88 * a read error.
90 struct page *tmppage;
93 /* When taking over an array from a different personality, we store
94 * the new thread here until we fully activate the array.
96 struct md_thread *thread;
100 * this is our 'private' RAID1 bio.
102 * it contains information about what kind of IO operations were started
103 * for this RAID1 operation, and about their status:
106 struct r1bio {
107 atomic_t remaining; /* 'have we finished' count,
108 * used from IRQ handlers
110 atomic_t behind_remaining; /* number of write-behind ios remaining
111 * in this BehindIO request
113 sector_t sector;
114 int sectors;
115 unsigned long state;
116 struct mddev *mddev;
118 * original bio going to /dev/mdx
120 struct bio *master_bio;
122 * if the IO is in READ direction, then this is where we read
124 int read_disk;
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;
131 * if the IO is in WRITE direction, then multiple bios are used.
132 * We choose the number when they are allocated.
134 struct bio *bios[0];
135 /* DO NOT PUT ANY NEW FIELDS HERE - bios array is contiguously alloced*/
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
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
148 #define IO_MADE_GOOD ((struct bio *)2)
150 #define BIO_SPECIAL(bio) ((unsigned long)bio <= 2)
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.
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...
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
172 #define R1BIO_MadeGood 7
173 #define R1BIO_WriteError 8
175 extern int md_raid1_congested(struct mddev *mddev, int bits);
177 #endif