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 94 /* poolinfo contains information about the content of the 95 * mempools - it changes when the array grows or shrinks 96 */ 97 struct pool_info *poolinfo; 98 mempool_t *r1bio_pool; 99 mempool_t *r1buf_pool; 100 101 /* temporary buffer to synchronous IO when attempting to repair 102 * a read error. 103 */ 104 struct page *tmppage; 105 106 107 /* When taking over an array from a different personality, we store 108 * the new thread here until we fully activate the array. 109 */ 110 struct md_thread *thread; 111}; 112 113/* 114 * this is our 'private' RAID1 bio. 115 * 116 * it contains information about what kind of IO operations were started 117 * for this RAID1 operation, and about their status: 118 */ 119 120struct r1bio { 121 atomic_t remaining; /* 'have we finished' count, 122 * used from IRQ handlers 123 */ 124 atomic_t behind_remaining; /* number of write-behind ios remaining 125 * in this BehindIO request 126 */ 127 sector_t sector; 128 sector_t start_next_window; 129 int sectors; 130 unsigned long state; 131 struct mddev *mddev; 132 /* 133 * original bio going to /dev/mdx 134 */ 135 struct bio *master_bio; 136 /* 137 * if the IO is in READ direction, then this is where we read 138 */ 139 int read_disk; 140 141 struct list_head retry_list; 142 /* Next two are only valid when R1BIO_BehindIO is set */ 143 struct bio_vec *behind_bvecs; 144 int behind_page_count; 145 /* 146 * if the IO is in WRITE direction, then multiple bios are used. 147 * We choose the number when they are allocated. 148 */ 149 struct bio *bios[0]; 150 /* DO NOT PUT ANY NEW FIELDS HERE - bios array is contiguously alloced*/ 151}; 152 153/* bits for r1bio.state */ 154#define R1BIO_Uptodate 0 155#define R1BIO_IsSync 1 156#define R1BIO_Degraded 2 157#define R1BIO_BehindIO 3 158/* Set ReadError on bios that experience a readerror so that 159 * raid1d knows what to do with them. 160 */ 161#define R1BIO_ReadError 4 162/* For write-behind requests, we call bi_end_io when 163 * the last non-write-behind device completes, providing 164 * any write was successful. Otherwise we call when 165 * any write-behind write succeeds, otherwise we call 166 * with failure when last write completes (and all failed). 167 * Record that bi_end_io was called with this flag... 168 */ 169#define R1BIO_Returned 6 170/* If a write for this request means we can clear some 171 * known-bad-block records, we set this flag 172 */ 173#define R1BIO_MadeGood 7 174#define R1BIO_WriteError 8 175 176extern int md_raid1_congested(struct mddev *mddev, int bits); 177 178#endif 179