1 | /* SPDX-License-Identifier: GPL-2.0 */ |
2 | #ifndef _RAID1_H |
3 | #define _RAID1_H |
4 | |
5 | /* |
6 | * each barrier unit size is 64MB fow now |
7 | * note: it must be larger than RESYNC_DEPTH |
8 | */ |
9 | #define BARRIER_UNIT_SECTOR_BITS 17 |
10 | #define BARRIER_UNIT_SECTOR_SIZE (1<<17) |
11 | /* |
12 | * In struct r1conf, the following members are related to I/O barrier |
13 | * buckets, |
14 | * atomic_t *nr_pending; |
15 | * atomic_t *nr_waiting; |
16 | * atomic_t *nr_queued; |
17 | * atomic_t *barrier; |
18 | * Each of them points to array of atomic_t variables, each array is |
19 | * designed to have BARRIER_BUCKETS_NR elements and occupy a single |
20 | * memory page. The data width of atomic_t variables is 4 bytes, equal |
21 | * to 1<<(ilog2(sizeof(atomic_t))), BARRIER_BUCKETS_NR_BITS is defined |
22 | * as (PAGE_SHIFT - ilog2(sizeof(int))) to make sure an array of |
23 | * atomic_t variables with BARRIER_BUCKETS_NR elements just exactly |
24 | * occupies a single memory page. |
25 | */ |
26 | #define BARRIER_BUCKETS_NR_BITS (PAGE_SHIFT - ilog2(sizeof(atomic_t))) |
27 | #define BARRIER_BUCKETS_NR (1<<BARRIER_BUCKETS_NR_BITS) |
28 | |
29 | /* Note: raid1_info.rdev can be set to NULL asynchronously by raid1_remove_disk. |
30 | * There are three safe ways to access raid1_info.rdev. |
31 | * 1/ when holding mddev->reconfig_mutex |
32 | * 2/ when resync/recovery is known to be happening - i.e. in code that is |
33 | * called as part of performing resync/recovery. |
34 | * 3/ while holding rcu_read_lock(), use rcu_dereference to get the pointer |
35 | * and if it is non-NULL, increment rdev->nr_pending before dropping the |
36 | * RCU lock. |
37 | * When .rdev is set to NULL, the nr_pending count checked again and if it has |
38 | * been incremented, the pointer is put back in .rdev. |
39 | */ |
40 | |
41 | struct raid1_info { |
42 | struct md_rdev *rdev; |
43 | sector_t head_position; |
44 | |
45 | /* When choose the best device for a read (read_balance()) |
46 | * we try to keep sequential reads one the same device |
47 | */ |
48 | sector_t next_seq_sect; |
49 | sector_t seq_start; |
50 | }; |
51 | |
52 | /* |
53 | * memory pools need a pointer to the mddev, so they can force an unplug |
54 | * when memory is tight, and a count of the number of drives that the |
55 | * pool was allocated for, so they know how much to allocate and free. |
56 | * mddev->raid_disks cannot be used, as it can change while a pool is active |
57 | * These two datums are stored in a kmalloced struct. |
58 | * The 'raid_disks' here is twice the raid_disks in r1conf. |
59 | * This allows space for each 'real' device can have a replacement in the |
60 | * second half of the array. |
61 | */ |
62 | |
63 | struct pool_info { |
64 | struct mddev *mddev; |
65 | int raid_disks; |
66 | }; |
67 | |
68 | struct r1conf { |
69 | struct mddev *mddev; |
70 | struct raid1_info *mirrors; /* twice 'raid_disks' to |
71 | * allow for replacements. |
72 | */ |
73 | int raid_disks; |
74 | int nonrot_disks; |
75 | |
76 | spinlock_t device_lock; |
77 | |
78 | /* list of 'struct r1bio' that need to be processed by raid1d, |
79 | * whether to retry a read, writeout a resync or recovery |
80 | * block, or anything else. |
81 | */ |
82 | struct list_head retry_list; |
83 | /* A separate list of r1bio which just need raid_end_bio_io called. |
84 | * This mustn't happen for writes which had any errors if the superblock |
85 | * needs to be written. |
86 | */ |
87 | struct list_head bio_end_io_list; |
88 | |
89 | /* queue pending writes to be submitted on unplug */ |
90 | struct bio_list pending_bio_list; |
91 | |
92 | /* for use when syncing mirrors: |
93 | * We don't allow both normal IO and resync/recovery IO at |
94 | * the same time - resync/recovery can only happen when there |
95 | * is no other IO. So when either is active, the other has to wait. |
96 | * See more details description in raid1.c near raise_barrier(). |
97 | */ |
98 | wait_queue_head_t wait_barrier; |
99 | spinlock_t resync_lock; |
100 | atomic_t nr_sync_pending; |
101 | atomic_t *nr_pending; |
102 | atomic_t *nr_waiting; |
103 | atomic_t *nr_queued; |
104 | atomic_t *barrier; |
105 | int array_frozen; |
106 | |
107 | /* Set to 1 if a full sync is needed, (fresh device added). |
108 | * Cleared when a sync completes. |
109 | */ |
110 | int fullsync; |
111 | |
112 | /* When the same as mddev->recovery_disabled we don't allow |
113 | * recovery to be attempted as we expect a read error. |
114 | */ |
115 | int recovery_disabled; |
116 | |
117 | /* poolinfo contains information about the content of the |
118 | * mempools - it changes when the array grows or shrinks |
119 | */ |
120 | struct pool_info *poolinfo; |
121 | mempool_t r1bio_pool; |
122 | mempool_t r1buf_pool; |
123 | |
124 | struct bio_set bio_split; |
125 | |
126 | /* temporary buffer to synchronous IO when attempting to repair |
127 | * a read error. |
128 | */ |
129 | struct page *tmppage; |
130 | |
131 | /* When taking over an array from a different personality, we store |
132 | * the new thread here until we fully activate the array. |
133 | */ |
134 | struct md_thread __rcu *thread; |
135 | |
136 | /* Keep track of cluster resync window to send to other |
137 | * nodes. |
138 | */ |
139 | sector_t cluster_sync_low; |
140 | sector_t cluster_sync_high; |
141 | |
142 | }; |
143 | |
144 | /* |
145 | * this is our 'private' RAID1 bio. |
146 | * |
147 | * it contains information about what kind of IO operations were started |
148 | * for this RAID1 operation, and about their status: |
149 | */ |
150 | |
151 | struct r1bio { |
152 | atomic_t remaining; /* 'have we finished' count, |
153 | * used from IRQ handlers |
154 | */ |
155 | atomic_t behind_remaining; /* number of write-behind ios remaining |
156 | * in this BehindIO request |
157 | */ |
158 | sector_t sector; |
159 | int sectors; |
160 | unsigned long state; |
161 | struct mddev *mddev; |
162 | /* |
163 | * original bio going to /dev/mdx |
164 | */ |
165 | struct bio *master_bio; |
166 | /* |
167 | * if the IO is in READ direction, then this is where we read |
168 | */ |
169 | int read_disk; |
170 | |
171 | struct list_head retry_list; |
172 | |
173 | /* |
174 | * When R1BIO_BehindIO is set, we store pages for write behind |
175 | * in behind_master_bio. |
176 | */ |
177 | struct bio *behind_master_bio; |
178 | |
179 | /* |
180 | * if the IO is in WRITE direction, then multiple bios are used. |
181 | * We choose the number when they are allocated. |
182 | */ |
183 | struct bio *bios[]; |
184 | /* DO NOT PUT ANY NEW FIELDS HERE - bios array is contiguously alloced*/ |
185 | }; |
186 | |
187 | /* bits for r1bio.state */ |
188 | enum r1bio_state { |
189 | R1BIO_Uptodate, |
190 | R1BIO_IsSync, |
191 | R1BIO_Degraded, |
192 | R1BIO_BehindIO, |
193 | /* Set ReadError on bios that experience a readerror so that |
194 | * raid1d knows what to do with them. |
195 | */ |
196 | R1BIO_ReadError, |
197 | /* For write-behind requests, we call bi_end_io when |
198 | * the last non-write-behind device completes, providing |
199 | * any write was successful. Otherwise we call when |
200 | * any write-behind write succeeds, otherwise we call |
201 | * with failure when last write completes (and all failed). |
202 | * Record that bi_end_io was called with this flag... |
203 | */ |
204 | R1BIO_Returned, |
205 | /* If a write for this request means we can clear some |
206 | * known-bad-block records, we set this flag |
207 | */ |
208 | R1BIO_MadeGood, |
209 | R1BIO_WriteError, |
210 | R1BIO_FailFast, |
211 | }; |
212 | |
213 | static inline int sector_to_idx(sector_t sector) |
214 | { |
215 | return hash_long(sector >> BARRIER_UNIT_SECTOR_BITS, |
216 | BARRIER_BUCKETS_NR_BITS); |
217 | } |
218 | #endif |
219 | |