1#ifndef _RAID1_H 2#define _RAID1_H 3 4struct 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 26struct pool_info { 27 struct mddev *mddev; 28 int raid_disks; 29}; 30 31struct 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 /* When raid1 starts resync, we divide array into four partitions 45 * |---------|--------------|---------------------|-------------| 46 * next_resync start_next_window end_window 47 * start_next_window = next_resync + NEXT_NORMALIO_DISTANCE 48 * end_window = start_next_window + NEXT_NORMALIO_DISTANCE 49 * current_window_requests means the count of normalIO between 50 * start_next_window and end_window. 51 * next_window_requests means the count of normalIO after end_window. 52 * */ 53 sector_t start_next_window; 54 int current_window_requests; 55 int next_window_requests; 56 57 spinlock_t device_lock; 58 59 /* list of 'struct r1bio' that need to be processed by raid1d, 60 * whether to retry a read, writeout a resync or recovery 61 * block, or anything else. 62 */ 63 struct list_head retry_list; 64 65 /* queue pending writes to be submitted on unplug */ 66 struct bio_list pending_bio_list; 67 int pending_count; 68 69 /* for use when syncing mirrors: 70 * We don't allow both normal IO and resync/recovery IO at 71 * the same time - resync/recovery can only happen when there 72 * is no other IO. So when either is active, the other has to wait. 73 * See more details description in raid1.c near raise_barrier(). 74 */ 75 wait_queue_head_t wait_barrier; 76 spinlock_t resync_lock; 77 int nr_pending; 78 int nr_waiting; 79 int nr_queued; 80 int barrier; 81 int array_frozen; 82 83 /* Set to 1 if a full sync is needed, (fresh device added). 84 * Cleared when a sync completes. 85 */ 86 int fullsync; 87 88 /* When the same as mddev->recovery_disabled we don't allow 89 * recovery to be attempted as we expect a read error. 90 */ 91 int recovery_disabled; 92 93 /* poolinfo contains information about the content of the 94 * mempools - it changes when the array grows or shrinks 95 */ 96 struct pool_info *poolinfo; 97 mempool_t *r1bio_pool; 98 mempool_t *r1buf_pool; 99 100 /* temporary buffer to synchronous IO when attempting to repair 101 * a read error. 102 */ 103 struct page *tmppage; 104 105 /* When taking over an array from a different personality, we store 106 * the new thread here until we fully activate the array. 107 */ 108 struct md_thread *thread; 109}; 110 111/* 112 * this is our 'private' RAID1 bio. 113 * 114 * it contains information about what kind of IO operations were started 115 * for this RAID1 operation, and about their status: 116 */ 117 118struct r1bio { 119 atomic_t remaining; /* 'have we finished' count, 120 * used from IRQ handlers 121 */ 122 atomic_t behind_remaining; /* number of write-behind ios remaining 123 * in this BehindIO request 124 */ 125 sector_t sector; 126 sector_t start_next_window; 127 int sectors; 128 unsigned long state; 129 struct mddev *mddev; 130 /* 131 * original bio going to /dev/mdx 132 */ 133 struct bio *master_bio; 134 /* 135 * if the IO is in READ direction, then this is where we read 136 */ 137 int read_disk; 138 139 struct list_head retry_list; 140 /* Next two are only valid when R1BIO_BehindIO is set */ 141 struct bio_vec *behind_bvecs; 142 int behind_page_count; 143 /* 144 * if the IO is in WRITE direction, then multiple bios are used. 145 * We choose the number when they are allocated. 146 */ 147 struct bio *bios[0]; 148 /* DO NOT PUT ANY NEW FIELDS HERE - bios array is contiguously alloced*/ 149}; 150 151/* bits for r1bio.state */ 152#define R1BIO_Uptodate 0 153#define R1BIO_IsSync 1 154#define R1BIO_Degraded 2 155#define R1BIO_BehindIO 3 156/* Set ReadError on bios that experience a readerror so that 157 * raid1d knows what to do with them. 158 */ 159#define R1BIO_ReadError 4 160/* For write-behind requests, we call bi_end_io when 161 * the last non-write-behind device completes, providing 162 * any write was successful. Otherwise we call when 163 * any write-behind write succeeds, otherwise we call 164 * with failure when last write completes (and all failed). 165 * Record that bi_end_io was called with this flag... 166 */ 167#define R1BIO_Returned 6 168/* If a write for this request means we can clear some 169 * known-bad-block records, we set this flag 170 */ 171#define R1BIO_MadeGood 7 172#define R1BIO_WriteError 8 173#endif 174