diff options
Diffstat (limited to 'drivers/md/raid1.h')
| -rw-r--r-- | drivers/md/raid1.h | 173 |
1 files changed, 173 insertions, 0 deletions
diff --git a/drivers/md/raid1.h b/drivers/md/raid1.h new file mode 100644 index 000000000..14ebb288c --- /dev/null +++ b/drivers/md/raid1.h @@ -0,0 +1,173 @@ +#ifndef _RAID1_H +#define _RAID1_H + +struct raid1_info { + struct md_rdev *rdev; + sector_t head_position; + + /* When choose the best device for a read (read_balance()) + * we try to keep sequential reads one the same device + */ + sector_t next_seq_sect; + sector_t seq_start; +}; + +/* + * memory pools need a pointer to the mddev, so they can force an unplug + * when memory is tight, and a count of the number of drives that the + * pool was allocated for, so they know how much to allocate and free. + * mddev->raid_disks cannot be used, as it can change while a pool is active + * These two datums are stored in a kmalloced struct. + * The 'raid_disks' here is twice the raid_disks in r1conf. + * This allows space for each 'real' device can have a replacement in the + * second half of the array. + */ + +struct pool_info { + struct mddev *mddev; + int raid_disks; +}; + +struct r1conf { + struct mddev *mddev; + struct raid1_info *mirrors; /* twice 'raid_disks' to + * allow for replacements. + */ + int raid_disks; + + /* During resync, read_balancing is only allowed on the part + * of the array that has been resynced. 'next_resync' tells us + * where that is. + */ + sector_t next_resync; + + /* When raid1 starts resync, we divide array into four partitions + * |---------|--------------|---------------------|-------------| + * next_resync start_next_window end_window + * start_next_window = next_resync + NEXT_NORMALIO_DISTANCE + * end_window = start_next_window + NEXT_NORMALIO_DISTANCE + * current_window_requests means the count of normalIO between + * start_next_window and end_window. + * next_window_requests means the count of normalIO after end_window. + * */ + sector_t start_next_window; + int current_window_requests; + int next_window_requests; + + spinlock_t device_lock; + + /* list of 'struct r1bio' that need to be processed by raid1d, + * whether to retry a read, writeout a resync or recovery + * block, or anything else. + */ + struct list_head retry_list; + + /* queue pending writes to be submitted on unplug */ + struct bio_list pending_bio_list; + int pending_count; + + /* for use when syncing mirrors: + * We don't allow both normal IO and resync/recovery IO at + * the same time - resync/recovery can only happen when there + * is no other IO. So when either is active, the other has to wait. + * See more details description in raid1.c near raise_barrier(). + */ + wait_queue_head_t wait_barrier; + spinlock_t resync_lock; + int nr_pending; + int nr_waiting; + int nr_queued; + int barrier; + int array_frozen; + + /* Set to 1 if a full sync is needed, (fresh device added). + * Cleared when a sync completes. + */ + int fullsync; + + /* When the same as mddev->recovery_disabled we don't allow + * recovery to be attempted as we expect a read error. + */ + int recovery_disabled; + + /* poolinfo contains information about the content of the + * mempools - it changes when the array grows or shrinks + */ + struct pool_info *poolinfo; + mempool_t *r1bio_pool; + mempool_t *r1buf_pool; + + /* temporary buffer to synchronous IO when attempting to repair + * a read error. + */ + struct page *tmppage; + + /* When taking over an array from a different personality, we store + * the new thread here until we fully activate the array. + */ + struct md_thread *thread; +}; + +/* + * this is our 'private' RAID1 bio. + * + * it contains information about what kind of IO operations were started + * for this RAID1 operation, and about their status: + */ + +struct r1bio { + atomic_t remaining; /* 'have we finished' count, + * used from IRQ handlers + */ + atomic_t behind_remaining; /* number of write-behind ios remaining + * in this BehindIO request + */ + sector_t sector; + sector_t start_next_window; + int sectors; + unsigned long state; + struct mddev *mddev; + /* + * original bio going to /dev/mdx + */ + struct bio *master_bio; + /* + * if the IO is in READ direction, then this is where we read + */ + int read_disk; + + struct list_head retry_list; + /* Next two are only valid when R1BIO_BehindIO is set */ + struct bio_vec *behind_bvecs; + int behind_page_count; + /* + * if the IO is in WRITE direction, then multiple bios are used. + * We choose the number when they are allocated. + */ + struct bio *bios[0]; + /* DO NOT PUT ANY NEW FIELDS HERE - bios array is contiguously alloced*/ +}; + +/* bits for r1bio.state */ +#define R1BIO_Uptodate 0 +#define R1BIO_IsSync 1 +#define R1BIO_Degraded 2 +#define R1BIO_BehindIO 3 +/* Set ReadError on bios that experience a readerror so that + * raid1d knows what to do with them. + */ +#define R1BIO_ReadError 4 +/* For write-behind requests, we call bi_end_io when + * the last non-write-behind device completes, providing + * any write was successful. Otherwise we call when + * any write-behind write succeeds, otherwise we call + * with failure when last write completes (and all failed). + * Record that bi_end_io was called with this flag... + */ +#define R1BIO_Returned 6 +/* If a write for this request means we can clear some + * known-bad-block records, we set this flag + */ +#define R1BIO_MadeGood 7 +#define R1BIO_WriteError 8 +#endif |