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 29struct raid1_info { 30 struct md_rdev *rdev; 31 sector_t head_position; 32 33 /* When choose the best device for a read (read_balance()) 34 * we try to keep sequential reads one the same device 35 */ 36 sector_t next_seq_sect; 37 sector_t seq_start; 38}; 39 40/* 41 * memory pools need a pointer to the mddev, so they can force an unplug 42 * when memory is tight, and a count of the number of drives that the 43 * pool was allocated for, so they know how much to allocate and free. 44 * mddev->raid_disks cannot be used, as it can change while a pool is active 45 * These two datums are stored in a kmalloced struct. 46 * The 'raid_disks' here is twice the raid_disks in r1conf. 47 * This allows space for each 'real' device can have a replacement in the 48 * second half of the array. 49 */ 50 51struct pool_info { 52 struct mddev *mddev; 53 int raid_disks; 54}; 55 56struct r1conf { 57 struct mddev *mddev; 58 struct raid1_info *mirrors; /* twice 'raid_disks' to 59 * allow for replacements. 60 */ 61 int raid_disks; 62 63 spinlock_t device_lock; 64 65 /* list of 'struct r1bio' that need to be processed by raid1d, 66 * whether to retry a read, writeout a resync or recovery 67 * block, or anything else. 68 */ 69 struct list_head retry_list; 70 /* A separate list of r1bio which just need raid_end_bio_io called. 71 * This mustn't happen for writes which had any errors if the superblock 72 * needs to be written. 73 */ 74 struct list_head bio_end_io_list; 75 76 /* queue pending writes to be submitted on unplug */ 77 struct bio_list pending_bio_list; 78 int pending_count; 79 80 /* for use when syncing mirrors: 81 * We don't allow both normal IO and resync/recovery IO at 82 * the same time - resync/recovery can only happen when there 83 * is no other IO. So when either is active, the other has to wait. 84 * See more details description in raid1.c near raise_barrier(). 85 */ 86 wait_queue_head_t wait_barrier; 87 spinlock_t resync_lock; 88 atomic_t nr_sync_pending; 89 atomic_t *nr_pending; 90 atomic_t *nr_waiting; 91 atomic_t *nr_queued; 92 atomic_t *barrier; 93 int array_frozen; 94 95 /* Set to 1 if a full sync is needed, (fresh device added). 96 * Cleared when a sync completes. 97 */ 98 int fullsync; 99 100 /* When the same as mddev->recovery_disabled we don't allow 101 * recovery to be attempted as we expect a read error. 102 */ 103 int recovery_disabled; 104 105 /* poolinfo contains information about the content of the 106 * mempools - it changes when the array grows or shrinks 107 */ 108 struct pool_info *poolinfo; 109 mempool_t *r1bio_pool; 110 mempool_t *r1buf_pool; 111 112 struct bio_set *bio_split; 113 114 /* temporary buffer to synchronous IO when attempting to repair 115 * a read error. 116 */ 117 struct page *tmppage; 118 119 /* When taking over an array from a different personality, we store 120 * the new thread here until we fully activate the array. 121 */ 122 struct md_thread *thread; 123 124 /* Keep track of cluster resync window to send to other 125 * nodes. 126 */ 127 sector_t cluster_sync_low; 128 sector_t cluster_sync_high; 129 130}; 131 132/* 133 * this is our 'private' RAID1 bio. 134 * 135 * it contains information about what kind of IO operations were started 136 * for this RAID1 operation, and about their status: 137 */ 138 139struct r1bio { 140 atomic_t remaining; /* 'have we finished' count, 141 * used from IRQ handlers 142 */ 143 atomic_t behind_remaining; /* number of write-behind ios remaining 144 * in this BehindIO request 145 */ 146 sector_t sector; 147 int sectors; 148 unsigned long state; 149 struct mddev *mddev; 150 /* 151 * original bio going to /dev/mdx 152 */ 153 struct bio *master_bio; 154 /* 155 * if the IO is in READ direction, then this is where we read 156 */ 157 int read_disk; 158 159 struct list_head retry_list; 160 161 /* 162 * When R1BIO_BehindIO is set, we store pages for write behind 163 * in behind_master_bio. 164 */ 165 struct bio *behind_master_bio; 166 167 /* 168 * if the IO is in WRITE direction, then multiple bios are used. 169 * We choose the number when they are allocated. 170 */ 171 struct bio *bios[0]; 172 /* DO NOT PUT ANY NEW FIELDS HERE - bios array is contiguously alloced*/ 173}; 174 175/* bits for r1bio.state */ 176enum r1bio_state { 177 R1BIO_Uptodate, 178 R1BIO_IsSync, 179 R1BIO_Degraded, 180 R1BIO_BehindIO, 181/* Set ReadError on bios that experience a readerror so that 182 * raid1d knows what to do with them. 183 */ 184 R1BIO_ReadError, 185/* For write-behind requests, we call bi_end_io when 186 * the last non-write-behind device completes, providing 187 * any write was successful. Otherwise we call when 188 * any write-behind write succeeds, otherwise we call 189 * with failure when last write completes (and all failed). 190 * Record that bi_end_io was called with this flag... 191 */ 192 R1BIO_Returned, 193/* If a write for this request means we can clear some 194 * known-bad-block records, we set this flag 195 */ 196 R1BIO_MadeGood, 197 R1BIO_WriteError, 198 R1BIO_FailFast, 199}; 200 201static inline int sector_to_idx(sector_t sector) 202{ 203 return hash_long(sector >> BARRIER_UNIT_SECTOR_BITS, 204 BARRIER_BUCKETS_NR_BITS); 205} 206#endif 207