Initial import

1 files changed, 696 insertions, 0 deletions

diff --git a/drivers/md/md.h b/drivers/md/md.h
new file mode 100644
index 000000000..4046a6c6f
--- /dev/null
+++ b/drivers/md/md.h
@@ -0,0 +1,696 @@
+/*
+   md.h : kernel internal structure of the Linux MD driver
+          Copyright (C) 1996-98 Ingo Molnar, Gadi Oxman
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2, or (at your option)
+   any later version.
+
+   You should have received a copy of the GNU General Public License
+   (for example /usr/src/linux/COPYING); if not, write to the Free
+   Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+*/
+
+#ifndef _MD_MD_H
+#define _MD_MD_H
+
+#include <linux/blkdev.h>
+#include <linux/kobject.h>
+#include <linux/list.h>
+#include <linux/mm.h>
+#include <linux/mutex.h>
+#include <linux/timer.h>
+#include <linux/wait.h>
+#include <linux/workqueue.h>
+#include "md-cluster.h"
+
+#define MaxSector (~(sector_t)0)
+
+/* Bad block numbers are stored sorted in a single page.
+ * 64bits is used for each block or extent.
+ * 54 bits are sector number, 9 bits are extent size,
+ * 1 bit is an 'acknowledged' flag.
+ */
+#define MD_MAX_BADBLOCKS	(PAGE_SIZE/8)
+
+/*
+ * MD's 'extended' device
+ */
+struct md_rdev {
+	struct list_head same_set;	/* RAID devices within the same set */
+
+	sector_t sectors;		/* Device size (in 512bytes sectors) */
+	struct mddev *mddev;		/* RAID array if running */
+	int last_events;		/* IO event timestamp */
+
+	/*
+	 * If meta_bdev is non-NULL, it means that a separate device is
+	 * being used to store the metadata (superblock/bitmap) which
+	 * would otherwise be contained on the same device as the data (bdev).
+	 */
+	struct block_device *meta_bdev;
+	struct block_device *bdev;	/* block device handle */
+
+	struct page	*sb_page, *bb_page;
+	int		sb_loaded;
+	__u64		sb_events;
+	sector_t	data_offset;	/* start of data in array */
+	sector_t	new_data_offset;/* only relevant while reshaping */
+	sector_t	sb_start;	/* offset of the super block (in 512byte sectors) */
+	int		sb_size;	/* bytes in the superblock */
+	int		preferred_minor;	/* autorun support */
+
+	struct kobject	kobj;
+
+	/* A device can be in one of three states based on two flags:
+	 * Not working:   faulty==1 in_sync==0
+	 * Fully working: faulty==0 in_sync==1
+	 * Working, but not
+	 * in sync with array
+	 *                faulty==0 in_sync==0
+	 *
+	 * It can never have faulty==1, in_sync==1
+	 * This reduces the burden of testing multiple flags in many cases
+	 */
+
+	unsigned long	flags;	/* bit set of 'enum flag_bits' bits. */
+	wait_queue_head_t blocked_wait;
+
+	int desc_nr;			/* descriptor index in the superblock */
+	int raid_disk;			/* role of device in array */
+	int new_raid_disk;		/* role that the device will have in
+					 * the array after a level-change completes.
+					 */
+	int saved_raid_disk;		/* role that device used to have in the
+					 * array and could again if we did a partial
+					 * resync from the bitmap
+					 */
+	sector_t	recovery_offset;/* If this device has been partially
+					 * recovered, this is where we were
+					 * up to.
+					 */
+
+	atomic_t	nr_pending;	/* number of pending requests.
+					 * only maintained for arrays that
+					 * support hot removal
+					 */
+	atomic_t	read_errors;	/* number of consecutive read errors that
+					 * we have tried to ignore.
+					 */
+	struct timespec last_read_error;	/* monotonic time since our
+						 * last read error
+						 */
+	atomic_t	corrected_errors; /* number of corrected read errors,
+					   * for reporting to userspace and storing
+					   * in superblock.
+					   */
+	struct work_struct del_work;	/* used for delayed sysfs removal */
+
+	struct kernfs_node *sysfs_state; /* handle for 'state'
+					   * sysfs entry */
+
+	struct badblocks {
+		int	count;		/* count of bad blocks */
+		int	unacked_exist;	/* there probably are unacknowledged
+					 * bad blocks.  This is only cleared
+					 * when a read discovers none
+					 */
+		int	shift;		/* shift from sectors to block size
+					 * a -ve shift means badblocks are
+					 * disabled.*/
+		u64	*page;		/* badblock list */
+		int	changed;
+		seqlock_t lock;
+
+		sector_t sector;
+		sector_t size;		/* in sectors */
+	} badblocks;
+};
+enum flag_bits {
+	Faulty,			/* device is known to have a fault */
+	In_sync,		/* device is in_sync with rest of array */
+	Bitmap_sync,		/* ..actually, not quite In_sync.  Need a
+				 * bitmap-based recovery to get fully in sync
+				 */
+	Unmerged,		/* device is being added to array and should
+				 * be considerred for bvec_merge_fn but not
+				 * yet for actual IO
+				 */
+	WriteMostly,		/* Avoid reading if at all possible */
+	AutoDetected,		/* added by auto-detect */
+	Blocked,		/* An error occurred but has not yet
+				 * been acknowledged by the metadata
+				 * handler, so don't allow writes
+				 * until it is cleared */
+	WriteErrorSeen,		/* A write error has been seen on this
+				 * device
+				 */
+	FaultRecorded,		/* Intermediate state for clearing
+				 * Blocked.  The Fault is/will-be
+				 * recorded in the metadata, but that
+				 * metadata hasn't been stored safely
+				 * on disk yet.
+				 */
+	BlockedBadBlocks,	/* A writer is blocked because they
+				 * found an unacknowledged bad-block.
+				 * This can safely be cleared at any
+				 * time, and the writer will re-check.
+				 * It may be set at any time, and at
+				 * worst the writer will timeout and
+				 * re-check.  So setting it as
+				 * accurately as possible is good, but
+				 * not absolutely critical.
+				 */
+	WantReplacement,	/* This device is a candidate to be
+				 * hot-replaced, either because it has
+				 * reported some faults, or because
+				 * of explicit request.
+				 */
+	Replacement,		/* This device is a replacement for
+				 * a want_replacement device with same
+				 * raid_disk number.
+				 */
+	Candidate,		/* For clustered environments only:
+				 * This device is seen locally but not
+				 * by the whole cluster
+				 */
+};
+
+#define BB_LEN_MASK	(0x00000000000001FFULL)
+#define BB_OFFSET_MASK	(0x7FFFFFFFFFFFFE00ULL)
+#define BB_ACK_MASK	(0x8000000000000000ULL)
+#define BB_MAX_LEN	512
+#define BB_OFFSET(x)	(((x) & BB_OFFSET_MASK) >> 9)
+#define BB_LEN(x)	(((x) & BB_LEN_MASK) + 1)
+#define BB_ACK(x)	(!!((x) & BB_ACK_MASK))
+#define BB_MAKE(a, l, ack) (((a)<<9) | ((l)-1) | ((u64)(!!(ack)) << 63))
+
+extern int md_is_badblock(struct badblocks *bb, sector_t s, int sectors,
+			  sector_t *first_bad, int *bad_sectors);
+static inline int is_badblock(struct md_rdev *rdev, sector_t s, int sectors,
+			      sector_t *first_bad, int *bad_sectors)
+{
+	if (unlikely(rdev->badblocks.count)) {
+		int rv = md_is_badblock(&rdev->badblocks, rdev->data_offset + s,
+					sectors,
+					first_bad, bad_sectors);
+		if (rv)
+			*first_bad -= rdev->data_offset;
+		return rv;
+	}
+	return 0;
+}
+extern int rdev_set_badblocks(struct md_rdev *rdev, sector_t s, int sectors,
+			      int is_new);
+extern int rdev_clear_badblocks(struct md_rdev *rdev, sector_t s, int sectors,
+				int is_new);
+extern void md_ack_all_badblocks(struct badblocks *bb);
+
+struct md_cluster_info;
+
+struct mddev {
+	void				*private;
+	struct md_personality		*pers;
+	dev_t				unit;
+	int				md_minor;
+	struct list_head		disks;
+	unsigned long			flags;
+#define MD_CHANGE_DEVS	0	/* Some device status has changed */
+#define MD_CHANGE_CLEAN 1	/* transition to or from 'clean' */
+#define MD_CHANGE_PENDING 2	/* switch from 'clean' to 'active' in progress */
+#define MD_UPDATE_SB_FLAGS (1 | 2 | 4)	/* If these are set, md_update_sb needed */
+#define MD_ARRAY_FIRST_USE 3    /* First use of array, needs initialization */
+#define MD_STILL_CLOSED	4	/* If set, then array has not been opened since
+				 * md_ioctl checked on it.
+				 */
+
+	int				suspended;
+	atomic_t			active_io;
+	int				ro;
+	int				sysfs_active; /* set when sysfs deletes
+						       * are happening, so run/
+						       * takeover/stop are not safe
+						       */
+	int				ready; /* See when safe to pass
+						* IO requests down */
+	struct gendisk			*gendisk;
+
+	struct kobject			kobj;
+	int				hold_active;
+#define	UNTIL_IOCTL	1
+#define	UNTIL_STOP	2
+
+	/* Superblock information */
+	int				major_version,
+					minor_version,
+					patch_version;
+	int				persistent;
+	int				external;	/* metadata is
+							 * managed externally */
+	char				metadata_type[17]; /* externally set*/
+	int				chunk_sectors;
+	time_t				ctime, utime;
+	int				level, layout;
+	char				clevel[16];
+	int				raid_disks;
+	int				max_disks;
+	sector_t			dev_sectors;	/* used size of
+							 * component devices */
+	sector_t			array_sectors; /* exported array size */
+	int				external_size; /* size managed
+							* externally */
+	__u64				events;
+	/* If the last 'event' was simply a clean->dirty transition, and
+	 * we didn't write it to the spares, then it is safe and simple
+	 * to just decrement the event count on a dirty->clean transition.
+	 * So we record that possibility here.
+	 */
+	int				can_decrease_events;
+
+	char				uuid[16];
+
+	/* If the array is being reshaped, we need to record the
+	 * new shape and an indication of where we are up to.
+	 * This is written to the superblock.
+	 * If reshape_position is MaxSector, then no reshape is happening (yet).
+	 */
+	sector_t			reshape_position;
+	int				delta_disks, new_level, new_layout;
+	int				new_chunk_sectors;
+	int				reshape_backwards;
+
+	struct md_thread		*thread;	/* management thread */
+	struct md_thread		*sync_thread;	/* doing resync or reconstruct */
+
+	/* 'last_sync_action' is initialized to "none".  It is set when a
+	 * sync operation (i.e "data-check", "requested-resync", "resync",
+	 * "recovery", or "reshape") is started.  It holds this value even
+	 * when the sync thread is "frozen" (interrupted) or "idle" (stopped
+	 * or finished).  It is overwritten when a new sync operation is begun.
+	 */
+	char				*last_sync_action;
+	sector_t			curr_resync;	/* last block scheduled */
+	/* As resync requests can complete out of order, we cannot easily track
+	 * how much resync has been completed.  So we occasionally pause until
+	 * everything completes, then set curr_resync_completed to curr_resync.
+	 * As such it may be well behind the real resync mark, but it is a value
+	 * we are certain of.
+	 */
+	sector_t			curr_resync_completed;
+	unsigned long			resync_mark;	/* a recent timestamp */
+	sector_t			resync_mark_cnt;/* blocks written at resync_mark */
+	sector_t			curr_mark_cnt; /* blocks scheduled now */
+
+	sector_t			resync_max_sectors; /* may be set by personality */
+
+	atomic64_t			resync_mismatches; /* count of sectors where
+							    * parity/replica mismatch found
+							    */
+
+	/* allow user-space to request suspension of IO to regions of the array */
+	sector_t			suspend_lo;
+	sector_t			suspend_hi;
+	/* if zero, use the system-wide default */
+	int				sync_speed_min;
+	int				sync_speed_max;
+
+	/* resync even though the same disks are shared among md-devices */
+	int				parallel_resync;
+
+	int				ok_start_degraded;
+	/* recovery/resync flags
+	 * NEEDED:   we might need to start a resync/recover
+	 * RUNNING:  a thread is running, or about to be started
+	 * SYNC:     actually doing a resync, not a recovery
+	 * RECOVER:  doing recovery, or need to try it.
+	 * INTR:     resync needs to be aborted for some reason
+	 * DONE:     thread is done and is waiting to be reaped
+	 * REQUEST:  user-space has requested a sync (used with SYNC)
+	 * CHECK:    user-space request for check-only, no repair
+	 * RESHAPE:  A reshape is happening
+	 * ERROR:    sync-action interrupted because io-error
+	 *
+	 * If neither SYNC or RESHAPE are set, then it is a recovery.
+	 */
+#define	MD_RECOVERY_RUNNING	0
+#define	MD_RECOVERY_SYNC	1
+#define	MD_RECOVERY_RECOVER	2
+#define	MD_RECOVERY_INTR	3
+#define	MD_RECOVERY_DONE	4
+#define	MD_RECOVERY_NEEDED	5
+#define	MD_RECOVERY_REQUESTED	6
+#define	MD_RECOVERY_CHECK	7
+#define MD_RECOVERY_RESHAPE	8
+#define	MD_RECOVERY_FROZEN	9
+#define	MD_RECOVERY_ERROR	10
+
+	unsigned long			recovery;
+	/* If a RAID personality determines that recovery (of a particular
+	 * device) will fail due to a read error on the source device, it
+	 * takes a copy of this number and does not attempt recovery again
+	 * until this number changes.
+	 */
+	int				recovery_disabled;
+
+	int				in_sync;	/* know to not need resync */
+	/* 'open_mutex' avoids races between 'md_open' and 'do_md_stop', so
+	 * that we are never stopping an array while it is open.
+	 * 'reconfig_mutex' protects all other reconfiguration.
+	 * These locks are separate due to conflicting interactions
+	 * with bdev->bd_mutex.
+	 * Lock ordering is:
+	 *  reconfig_mutex -> bd_mutex : e.g. do_md_run -> revalidate_disk
+	 *  bd_mutex -> open_mutex:  e.g. __blkdev_get -> md_open
+	 */
+	struct mutex			open_mutex;
+	struct mutex			reconfig_mutex;
+	atomic_t			active;		/* general refcount */
+	atomic_t			openers;	/* number of active opens */
+
+	int				changed;	/* True if we might need to
+							 * reread partition info */
+	int				degraded;	/* whether md should consider
+							 * adding a spare
+							 */
+	int				merge_check_needed; /* at least one
+							     * member device
+							     * has a
+							     * merge_bvec_fn */
+
+	atomic_t			recovery_active; /* blocks scheduled, but not written */
+	wait_queue_head_t		recovery_wait;
+	sector_t			recovery_cp;
+	sector_t			resync_min;	/* user requested sync
+							 * starts here */
+	sector_t			resync_max;	/* resync should pause
+							 * when it gets here */
+
+	struct kernfs_node		*sysfs_state;	/* handle for 'array_state'
+							 * file in sysfs.
+							 */
+	struct kernfs_node		*sysfs_action;  /* handle for 'sync_action' */
+
+	struct work_struct del_work;	/* used for delayed sysfs removal */
+
+	/* "lock" protects:
+	 *   flush_bio transition from NULL to !NULL
+	 *   rdev superblocks, events
+	 *   clearing MD_CHANGE_*
+	 *   in_sync - and related safemode and MD_CHANGE changes
+	 *   pers (also protected by reconfig_mutex and pending IO).
+	 *   clearing ->bitmap
+	 *   clearing ->bitmap_info.file
+	 *   changing ->resync_{min,max}
+	 *   setting MD_RECOVERY_RUNNING (which interacts with resync_{min,max})
+	 */
+	spinlock_t			lock;
+	wait_queue_head_t		sb_wait;	/* for waiting on superblock updates */
+	atomic_t			pending_writes;	/* number of active superblock writes */
+
+	unsigned int			safemode;	/* if set, update "clean" superblock
+							 * when no writes pending.
+							 */
+	unsigned int			safemode_delay;
+	struct timer_list		safemode_timer;
+	atomic_t			writes_pending;
+	struct request_queue		*queue;	/* for plugging ... */
+
+	struct bitmap			*bitmap; /* the bitmap for the device */
+	struct {
+		struct file		*file; /* the bitmap file */
+		loff_t			offset; /* offset from superblock of
+						 * start of bitmap. May be
+						 * negative, but not '0'
+						 * For external metadata, offset
+						 * from start of device.
+						 */
+		unsigned long		space; /* space available at this offset */
+		loff_t			default_offset; /* this is the offset to use when
+							 * hot-adding a bitmap.  It should
+							 * eventually be settable by sysfs.
+							 */
+		unsigned long		default_space; /* space available at
+							* default offset */
+		struct mutex		mutex;
+		unsigned long		chunksize;
+		unsigned long		daemon_sleep; /* how many jiffies between updates? */
+		unsigned long		max_write_behind; /* write-behind mode */
+		int			external;
+		int			nodes; /* Maximum number of nodes in the cluster */
+		char                    cluster_name[64]; /* Name of the cluster */
+	} bitmap_info;
+
+	atomic_t			max_corr_read_errors; /* max read retries */
+	struct list_head		all_mddevs;
+
+	struct attribute_group		*to_remove;
+
+	struct bio_set			*bio_set;
+
+	/* Generic flush handling.
+	 * The last to finish preflush schedules a worker to submit
+	 * the rest of the request (without the REQ_FLUSH flag).
+	 */
+	struct bio *flush_bio;
+	atomic_t flush_pending;
+	struct work_struct flush_work;
+	struct work_struct event_work;	/* used by dm to report failure event */
+	void (*sync_super)(struct mddev *mddev, struct md_rdev *rdev);
+	struct md_cluster_info		*cluster_info;
+};
+
+static inline int __must_check mddev_lock(struct mddev *mddev)
+{
+	return mutex_lock_interruptible(&mddev->reconfig_mutex);
+}
+
+/* Sometimes we need to take the lock in a situation where
+ * failure due to interrupts is not acceptable.
+ */
+static inline void mddev_lock_nointr(struct mddev *mddev)
+{
+	mutex_lock(&mddev->reconfig_mutex);
+}
+
+static inline int mddev_is_locked(struct mddev *mddev)
+{
+	return mutex_is_locked(&mddev->reconfig_mutex);
+}
+
+static inline int mddev_trylock(struct mddev *mddev)
+{
+	return mutex_trylock(&mddev->reconfig_mutex);
+}
+extern void mddev_unlock(struct mddev *mddev);
+
+static inline void md_sync_acct(struct block_device *bdev, unsigned long nr_sectors)
+{
+	atomic_add(nr_sectors, &bdev->bd_contains->bd_disk->sync_io);
+}
+
+struct md_personality
+{
+	char *name;
+	int level;
+	struct list_head list;
+	struct module *owner;
+	void (*make_request)(struct mddev *mddev, struct bio *bio);
+	int (*run)(struct mddev *mddev);
+	void (*free)(struct mddev *mddev, void *priv);
+	void (*status)(struct seq_file *seq, struct mddev *mddev);
+	/* error_handler must set ->faulty and clear ->in_sync
+	 * if appropriate, and should abort recovery if needed
+	 */
+	void (*error_handler)(struct mddev *mddev, struct md_rdev *rdev);
+	int (*hot_add_disk) (struct mddev *mddev, struct md_rdev *rdev);
+	int (*hot_remove_disk) (struct mddev *mddev, struct md_rdev *rdev);
+	int (*spare_active) (struct mddev *mddev);
+	sector_t (*sync_request)(struct mddev *mddev, sector_t sector_nr, int *skipped);
+	int (*resize) (struct mddev *mddev, sector_t sectors);
+	sector_t (*size) (struct mddev *mddev, sector_t sectors, int raid_disks);
+	int (*check_reshape) (struct mddev *mddev);
+	int (*start_reshape) (struct mddev *mddev);
+	void (*finish_reshape) (struct mddev *mddev);
+	/* quiesce moves between quiescence states
+	 * 0 - fully active
+	 * 1 - no new requests allowed
+	 * others - reserved
+	 */
+	void (*quiesce) (struct mddev *mddev, int state);
+	/* takeover is used to transition an array from one
+	 * personality to another.  The new personality must be able
+	 * to handle the data in the current layout.
+	 * e.g. 2drive raid1 -> 2drive raid5
+	 *      ndrive raid5 -> degraded n+1drive raid6 with special layout
+	 * If the takeover succeeds, a new 'private' structure is returned.
+	 * This needs to be installed and then ->run used to activate the
+	 * array.
+	 */
+	void *(*takeover) (struct mddev *mddev);
+	/* congested implements bdi.congested_fn().
+	 * Will not be called while array is 'suspended' */
+	int (*congested)(struct mddev *mddev, int bits);
+	/* mergeable_bvec is use to implement ->merge_bvec_fn */
+	int (*mergeable_bvec)(struct mddev *mddev,
+			      struct bvec_merge_data *bvm,
+			      struct bio_vec *biovec);
+};
+
+struct md_sysfs_entry {
+	struct attribute attr;
+	ssize_t (*show)(struct mddev *, char *);
+	ssize_t (*store)(struct mddev *, const char *, size_t);
+};
+extern struct attribute_group md_bitmap_group;
+
+static inline struct kernfs_node *sysfs_get_dirent_safe(struct kernfs_node *sd, char *name)
+{
+	if (sd)
+		return sysfs_get_dirent(sd, name);
+	return sd;
+}
+static inline void sysfs_notify_dirent_safe(struct kernfs_node *sd)
+{
+	if (sd)
+		sysfs_notify_dirent(sd);
+}
+
+static inline char * mdname (struct mddev * mddev)
+{
+	return mddev->gendisk ? mddev->gendisk->disk_name : "mdX";
+}
+
+static inline int sysfs_link_rdev(struct mddev *mddev, struct md_rdev *rdev)
+{
+	char nm[20];
+	if (!test_bit(Replacement, &rdev->flags) && mddev->kobj.sd) {
+		sprintf(nm, "rd%d", rdev->raid_disk);
+		return sysfs_create_link(&mddev->kobj, &rdev->kobj, nm);
+	} else
+		return 0;
+}
+
+static inline void sysfs_unlink_rdev(struct mddev *mddev, struct md_rdev *rdev)
+{
+	char nm[20];
+	if (!test_bit(Replacement, &rdev->flags) && mddev->kobj.sd) {
+		sprintf(nm, "rd%d", rdev->raid_disk);
+		sysfs_remove_link(&mddev->kobj, nm);
+	}
+}
+
+/*
+ * iterates through some rdev ringlist. It's safe to remove the
+ * current 'rdev'. Dont touch 'tmp' though.
+ */
+#define rdev_for_each_list(rdev, tmp, head)				\
+	list_for_each_entry_safe(rdev, tmp, head, same_set)
+
+/*
+ * iterates through the 'same array disks' ringlist
+ */
+#define rdev_for_each(rdev, mddev)				\
+	list_for_each_entry(rdev, &((mddev)->disks), same_set)
+
+#define rdev_for_each_safe(rdev, tmp, mddev)				\
+	list_for_each_entry_safe(rdev, tmp, &((mddev)->disks), same_set)
+
+#define rdev_for_each_rcu(rdev, mddev)				\
+	list_for_each_entry_rcu(rdev, &((mddev)->disks), same_set)
+
+struct md_thread {
+	void			(*run) (struct md_thread *thread);
+	struct mddev		*mddev;
+	wait_queue_head_t	wqueue;
+	unsigned long		flags;
+	struct task_struct	*tsk;
+	unsigned long		timeout;
+	void			*private;
+};
+
+#define THREAD_WAKEUP  0
+
+static inline void safe_put_page(struct page *p)
+{
+	if (p) put_page(p);
+}
+
+extern int register_md_personality(struct md_personality *p);
+extern int unregister_md_personality(struct md_personality *p);
+extern int register_md_cluster_operations(struct md_cluster_operations *ops,
+		struct module *module);
+extern int unregister_md_cluster_operations(void);
+extern int md_setup_cluster(struct mddev *mddev, int nodes);
+extern void md_cluster_stop(struct mddev *mddev);
+extern struct md_thread *md_register_thread(
+	void (*run)(struct md_thread *thread),
+	struct mddev *mddev,
+	const char *name);
+extern void md_unregister_thread(struct md_thread **threadp);
+extern void md_wakeup_thread(struct md_thread *thread);
+extern void md_check_recovery(struct mddev *mddev);
+extern void md_reap_sync_thread(struct mddev *mddev);
+extern void md_write_start(struct mddev *mddev, struct bio *bi);
+extern void md_write_end(struct mddev *mddev);
+extern void md_done_sync(struct mddev *mddev, int blocks, int ok);
+extern void md_error(struct mddev *mddev, struct md_rdev *rdev);
+extern void md_finish_reshape(struct mddev *mddev);
+
+extern int mddev_congested(struct mddev *mddev, int bits);
+extern void md_flush_request(struct mddev *mddev, struct bio *bio);
+extern void md_super_write(struct mddev *mddev, struct md_rdev *rdev,
+			   sector_t sector, int size, struct page *page);
+extern void md_super_wait(struct mddev *mddev);
+extern int sync_page_io(struct md_rdev *rdev, sector_t sector, int size,
+			struct page *page, int rw, bool metadata_op);
+extern void md_do_sync(struct md_thread *thread);
+extern void md_new_event(struct mddev *mddev);
+extern int md_allow_write(struct mddev *mddev);
+extern void md_wait_for_blocked_rdev(struct md_rdev *rdev, struct mddev *mddev);
+extern void md_set_array_sectors(struct mddev *mddev, sector_t array_sectors);
+extern int md_check_no_bitmap(struct mddev *mddev);
+extern int md_integrity_register(struct mddev *mddev);
+extern void md_integrity_add_rdev(struct md_rdev *rdev, struct mddev *mddev);
+extern int strict_strtoul_scaled(const char *cp, unsigned long *res, int scale);
+
+extern void mddev_init(struct mddev *mddev);
+extern int md_run(struct mddev *mddev);
+extern void md_stop(struct mddev *mddev);
+extern void md_stop_writes(struct mddev *mddev);
+extern int md_rdev_init(struct md_rdev *rdev);
+extern void md_rdev_clear(struct md_rdev *rdev);
+
+extern void mddev_suspend(struct mddev *mddev);
+extern void mddev_resume(struct mddev *mddev);
+extern struct bio *bio_clone_mddev(struct bio *bio, gfp_t gfp_mask,
+				   struct mddev *mddev);
+extern struct bio *bio_alloc_mddev(gfp_t gfp_mask, int nr_iovecs,
+				   struct mddev *mddev);
+
+extern void md_unplug(struct blk_plug_cb *cb, bool from_schedule);
+extern void md_reload_sb(struct mddev *mddev);
+extern void md_update_sb(struct mddev *mddev, int force);
+extern void md_kick_rdev_from_array(struct md_rdev * rdev);
+struct md_rdev *md_find_rdev_nr_rcu(struct mddev *mddev, int nr);
+static inline int mddev_check_plugged(struct mddev *mddev)
+{
+	return !!blk_check_plugged(md_unplug, mddev,
+				   sizeof(struct blk_plug_cb));
+}
+
+static inline void rdev_dec_pending(struct md_rdev *rdev, struct mddev *mddev)
+{
+	int faulty = test_bit(Faulty, &rdev->flags);
+	if (atomic_dec_and_test(&rdev->nr_pending) && faulty) {
+		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
+		md_wakeup_thread(mddev->thread);
+	}
+}
+
+extern struct md_cluster_operations *md_cluster_ops;
+static inline int mddev_is_clustered(struct mddev *mddev)
+{
+	return mddev->cluster_info && mddev->bitmap_info.nodes > 1;
+}
+#endif /* _MD_MD_H */