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1 | #ifndef _RAID1_H | |
2 | #define _RAID1_H | |
3 | ||
4 | struct raid1_info { | |
5 | struct md_rdev *rdev; | |
6 | sector_t head_position; | |
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; | |
12 | sector_t seq_start; | |
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. | |
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. | |
24 | */ | |
25 | ||
26 | struct pool_info { | |
27 | struct mddev *mddev; | |
28 | int raid_disks; | |
29 | }; | |
30 | ||
31 | struct r1conf { | |
32 | struct mddev *mddev; | |
33 | struct raid1_info *mirrors; /* twice 'raid_disks' to | |
34 | * allow for replacements. | |
35 | */ | |
36 | int raid_disks; | |
37 | ||
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 | ||
106 | struct 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 | /* bits for r1bio.state */ | |
139 | #define R1BIO_Uptodate 0 | |
140 | #define R1BIO_IsSync 1 | |
141 | #define R1BIO_Degraded 2 | |
142 | #define R1BIO_BehindIO 3 | |
143 | /* Set ReadError on bios that experience a readerror so that | |
144 | * raid1d knows what to do with them. | |
145 | */ | |
146 | #define R1BIO_ReadError 4 | |
147 | /* For write-behind requests, we call bi_end_io when | |
148 | * the last non-write-behind device completes, providing | |
149 | * any write was successful. Otherwise we call when | |
150 | * any write-behind write succeeds, otherwise we call | |
151 | * with failure when last write completes (and all failed). | |
152 | * Record that bi_end_io was called with this flag... | |
153 | */ | |
154 | #define R1BIO_Returned 6 | |
155 | /* If a write for this request means we can clear some | |
156 | * known-bad-block records, we set this flag | |
157 | */ | |
158 | #define R1BIO_MadeGood 7 | |
159 | #define R1BIO_WriteError 8 | |
160 | ||
161 | extern int md_raid1_congested(struct mddev *mddev, int bits); | |
162 | ||
163 | #endif |