#ifndef _RAID1_H#define _RAID1_H /* * each barrier unit size is 64MB fow now * note: it must be larger than RESYNC_DEPTH */#define BARRIER_UNIT_SECTOR_BITS	17#define BARRIER_UNIT_SECTOR_SIZE	(1<<17)/* * In struct r1conf, the following members are related to I/O barrier * buckets, *	atomic_t	*nr_pending; *	atomic_t	*nr_waiting; *	atomic_t	*nr_queued; *	atomic_t	*barrier; * Each of them points to array of atomic_t variables, each array is * designed to have BARRIER_BUCKETS_NR elements and occupy a single * memory page. The data width of atomic_t variables is 4 bytes, equal * to 1<<(ilog2(sizeof(atomic_t))), BARRIER_BUCKETS_NR_BITS is defined * as (PAGE_SHIFT - ilog2(sizeof(int))) to make sure an array of * atomic_t variables with BARRIER_BUCKETS_NR elements just exactly * occupies a single memory page. */#define BARRIER_BUCKETS_NR_BITS		(PAGE_SHIFT - ilog2(sizeof(atomic_t)))#define BARRIER_BUCKETS_NR		(1<<BARRIER_BUCKETS_NR_BITS) 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; 	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;	/* A separate list of r1bio which just need raid_end_bio_io called.	 * This mustn't happen for writes which had any errors if the superblock	 * needs to be written.	 */	struct list_head	bio_end_io_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;	atomic_t		nr_sync_pending;	atomic_t		*nr_pending;	atomic_t		*nr_waiting;	atomic_t		*nr_queued;	atomic_t		*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; 	struct bio_set		*bio_split; 	/* 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; 	/* Keep track of cluster resync window to send to other	 * nodes.	 */	sector_t		cluster_sync_low;	sector_t		cluster_sync_high; }; /* * 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;	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; 	/*	 * When R1BIO_BehindIO is set, we store pages for write behind	 * in behind_master_bio.	 */	struct bio		*behind_master_bio; 	/*	 * 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 */enum r1bio_state {	R1BIO_Uptodate,	R1BIO_IsSync,	R1BIO_Degraded,	R1BIO_BehindIO,/* Set ReadError on bios that experience a readerror so that * raid1d knows what to do with them. */	R1BIO_ReadError,/* 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... */	R1BIO_Returned,/* If a write for this request means we can clear some * known-bad-block records, we set this flag */	R1BIO_MadeGood,	R1BIO_WriteError,	R1BIO_FailFast,}; static inline int sector_to_idx(sector_t sector){	return hash_long(sector >> BARRIER_UNIT_SECTOR_BITS,			 BARRIER_BUCKETS_NR_BITS);}#endif