xref: /openbmc/linux/drivers/md/md.h (revision c819e2cf)
1 /*
2    md.h : kernel internal structure of the Linux MD driver
3           Copyright (C) 1996-98 Ingo Molnar, Gadi Oxman
4 
5    This program is free software; you can redistribute it and/or modify
6    it under the terms of the GNU General Public License as published by
7    the Free Software Foundation; either version 2, or (at your option)
8    any later version.
9 
10    You should have received a copy of the GNU General Public License
11    (for example /usr/src/linux/COPYING); if not, write to the Free
12    Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
13 */
14 
15 #ifndef _MD_MD_H
16 #define _MD_MD_H
17 
18 #include <linux/blkdev.h>
19 #include <linux/kobject.h>
20 #include <linux/list.h>
21 #include <linux/mm.h>
22 #include <linux/mutex.h>
23 #include <linux/timer.h>
24 #include <linux/wait.h>
25 #include <linux/workqueue.h>
26 
27 #define MaxSector (~(sector_t)0)
28 
29 /* Bad block numbers are stored sorted in a single page.
30  * 64bits is used for each block or extent.
31  * 54 bits are sector number, 9 bits are extent size,
32  * 1 bit is an 'acknowledged' flag.
33  */
34 #define MD_MAX_BADBLOCKS	(PAGE_SIZE/8)
35 
36 /*
37  * MD's 'extended' device
38  */
39 struct md_rdev {
40 	struct list_head same_set;	/* RAID devices within the same set */
41 
42 	sector_t sectors;		/* Device size (in 512bytes sectors) */
43 	struct mddev *mddev;		/* RAID array if running */
44 	int last_events;		/* IO event timestamp */
45 
46 	/*
47 	 * If meta_bdev is non-NULL, it means that a separate device is
48 	 * being used to store the metadata (superblock/bitmap) which
49 	 * would otherwise be contained on the same device as the data (bdev).
50 	 */
51 	struct block_device *meta_bdev;
52 	struct block_device *bdev;	/* block device handle */
53 
54 	struct page	*sb_page, *bb_page;
55 	int		sb_loaded;
56 	__u64		sb_events;
57 	sector_t	data_offset;	/* start of data in array */
58 	sector_t	new_data_offset;/* only relevant while reshaping */
59 	sector_t	sb_start;	/* offset of the super block (in 512byte sectors) */
60 	int		sb_size;	/* bytes in the superblock */
61 	int		preferred_minor;	/* autorun support */
62 
63 	struct kobject	kobj;
64 
65 	/* A device can be in one of three states based on two flags:
66 	 * Not working:   faulty==1 in_sync==0
67 	 * Fully working: faulty==0 in_sync==1
68 	 * Working, but not
69 	 * in sync with array
70 	 *                faulty==0 in_sync==0
71 	 *
72 	 * It can never have faulty==1, in_sync==1
73 	 * This reduces the burden of testing multiple flags in many cases
74 	 */
75 
76 	unsigned long	flags;	/* bit set of 'enum flag_bits' bits. */
77 	wait_queue_head_t blocked_wait;
78 
79 	int desc_nr;			/* descriptor index in the superblock */
80 	int raid_disk;			/* role of device in array */
81 	int new_raid_disk;		/* role that the device will have in
82 					 * the array after a level-change completes.
83 					 */
84 	int saved_raid_disk;		/* role that device used to have in the
85 					 * array and could again if we did a partial
86 					 * resync from the bitmap
87 					 */
88 	sector_t	recovery_offset;/* If this device has been partially
89 					 * recovered, this is where we were
90 					 * up to.
91 					 */
92 
93 	atomic_t	nr_pending;	/* number of pending requests.
94 					 * only maintained for arrays that
95 					 * support hot removal
96 					 */
97 	atomic_t	read_errors;	/* number of consecutive read errors that
98 					 * we have tried to ignore.
99 					 */
100 	struct timespec last_read_error;	/* monotonic time since our
101 						 * last read error
102 						 */
103 	atomic_t	corrected_errors; /* number of corrected read errors,
104 					   * for reporting to userspace and storing
105 					   * in superblock.
106 					   */
107 	struct work_struct del_work;	/* used for delayed sysfs removal */
108 
109 	struct kernfs_node *sysfs_state; /* handle for 'state'
110 					   * sysfs entry */
111 
112 	struct badblocks {
113 		int	count;		/* count of bad blocks */
114 		int	unacked_exist;	/* there probably are unacknowledged
115 					 * bad blocks.  This is only cleared
116 					 * when a read discovers none
117 					 */
118 		int	shift;		/* shift from sectors to block size
119 					 * a -ve shift means badblocks are
120 					 * disabled.*/
121 		u64	*page;		/* badblock list */
122 		int	changed;
123 		seqlock_t lock;
124 
125 		sector_t sector;
126 		sector_t size;		/* in sectors */
127 	} badblocks;
128 };
129 enum flag_bits {
130 	Faulty,			/* device is known to have a fault */
131 	In_sync,		/* device is in_sync with rest of array */
132 	Bitmap_sync,		/* ..actually, not quite In_sync.  Need a
133 				 * bitmap-based recovery to get fully in sync
134 				 */
135 	Unmerged,		/* device is being added to array and should
136 				 * be considerred for bvec_merge_fn but not
137 				 * yet for actual IO
138 				 */
139 	WriteMostly,		/* Avoid reading if at all possible */
140 	AutoDetected,		/* added by auto-detect */
141 	Blocked,		/* An error occurred but has not yet
142 				 * been acknowledged by the metadata
143 				 * handler, so don't allow writes
144 				 * until it is cleared */
145 	WriteErrorSeen,		/* A write error has been seen on this
146 				 * device
147 				 */
148 	FaultRecorded,		/* Intermediate state for clearing
149 				 * Blocked.  The Fault is/will-be
150 				 * recorded in the metadata, but that
151 				 * metadata hasn't been stored safely
152 				 * on disk yet.
153 				 */
154 	BlockedBadBlocks,	/* A writer is blocked because they
155 				 * found an unacknowledged bad-block.
156 				 * This can safely be cleared at any
157 				 * time, and the writer will re-check.
158 				 * It may be set at any time, and at
159 				 * worst the writer will timeout and
160 				 * re-check.  So setting it as
161 				 * accurately as possible is good, but
162 				 * not absolutely critical.
163 				 */
164 	WantReplacement,	/* This device is a candidate to be
165 				 * hot-replaced, either because it has
166 				 * reported some faults, or because
167 				 * of explicit request.
168 				 */
169 	Replacement,		/* This device is a replacement for
170 				 * a want_replacement device with same
171 				 * raid_disk number.
172 				 */
173 };
174 
175 #define BB_LEN_MASK	(0x00000000000001FFULL)
176 #define BB_OFFSET_MASK	(0x7FFFFFFFFFFFFE00ULL)
177 #define BB_ACK_MASK	(0x8000000000000000ULL)
178 #define BB_MAX_LEN	512
179 #define BB_OFFSET(x)	(((x) & BB_OFFSET_MASK) >> 9)
180 #define BB_LEN(x)	(((x) & BB_LEN_MASK) + 1)
181 #define BB_ACK(x)	(!!((x) & BB_ACK_MASK))
182 #define BB_MAKE(a, l, ack) (((a)<<9) | ((l)-1) | ((u64)(!!(ack)) << 63))
183 
184 extern int md_is_badblock(struct badblocks *bb, sector_t s, int sectors,
185 			  sector_t *first_bad, int *bad_sectors);
186 static inline int is_badblock(struct md_rdev *rdev, sector_t s, int sectors,
187 			      sector_t *first_bad, int *bad_sectors)
188 {
189 	if (unlikely(rdev->badblocks.count)) {
190 		int rv = md_is_badblock(&rdev->badblocks, rdev->data_offset + s,
191 					sectors,
192 					first_bad, bad_sectors);
193 		if (rv)
194 			*first_bad -= rdev->data_offset;
195 		return rv;
196 	}
197 	return 0;
198 }
199 extern int rdev_set_badblocks(struct md_rdev *rdev, sector_t s, int sectors,
200 			      int is_new);
201 extern int rdev_clear_badblocks(struct md_rdev *rdev, sector_t s, int sectors,
202 				int is_new);
203 extern void md_ack_all_badblocks(struct badblocks *bb);
204 
205 struct mddev {
206 	void				*private;
207 	struct md_personality		*pers;
208 	dev_t				unit;
209 	int				md_minor;
210 	struct list_head		disks;
211 	unsigned long			flags;
212 #define MD_CHANGE_DEVS	0	/* Some device status has changed */
213 #define MD_CHANGE_CLEAN 1	/* transition to or from 'clean' */
214 #define MD_CHANGE_PENDING 2	/* switch from 'clean' to 'active' in progress */
215 #define MD_UPDATE_SB_FLAGS (1 | 2 | 4)	/* If these are set, md_update_sb needed */
216 #define MD_ARRAY_FIRST_USE 3    /* First use of array, needs initialization */
217 #define MD_STILL_CLOSED	4	/* If set, then array has not been opened since
218 				 * md_ioctl checked on it.
219 				 */
220 
221 	int				suspended;
222 	atomic_t			active_io;
223 	int				ro;
224 	int				sysfs_active; /* set when sysfs deletes
225 						       * are happening, so run/
226 						       * takeover/stop are not safe
227 						       */
228 	int				ready; /* See when safe to pass
229 						* IO requests down */
230 	struct gendisk			*gendisk;
231 
232 	struct kobject			kobj;
233 	int				hold_active;
234 #define	UNTIL_IOCTL	1
235 #define	UNTIL_STOP	2
236 
237 	/* Superblock information */
238 	int				major_version,
239 					minor_version,
240 					patch_version;
241 	int				persistent;
242 	int				external;	/* metadata is
243 							 * managed externally */
244 	char				metadata_type[17]; /* externally set*/
245 	int				chunk_sectors;
246 	time_t				ctime, utime;
247 	int				level, layout;
248 	char				clevel[16];
249 	int				raid_disks;
250 	int				max_disks;
251 	sector_t			dev_sectors;	/* used size of
252 							 * component devices */
253 	sector_t			array_sectors; /* exported array size */
254 	int				external_size; /* size managed
255 							* externally */
256 	__u64				events;
257 	/* If the last 'event' was simply a clean->dirty transition, and
258 	 * we didn't write it to the spares, then it is safe and simple
259 	 * to just decrement the event count on a dirty->clean transition.
260 	 * So we record that possibility here.
261 	 */
262 	int				can_decrease_events;
263 
264 	char				uuid[16];
265 
266 	/* If the array is being reshaped, we need to record the
267 	 * new shape and an indication of where we are up to.
268 	 * This is written to the superblock.
269 	 * If reshape_position is MaxSector, then no reshape is happening (yet).
270 	 */
271 	sector_t			reshape_position;
272 	int				delta_disks, new_level, new_layout;
273 	int				new_chunk_sectors;
274 	int				reshape_backwards;
275 
276 	struct md_thread		*thread;	/* management thread */
277 	struct md_thread		*sync_thread;	/* doing resync or reconstruct */
278 
279 	/* 'last_sync_action' is initialized to "none".  It is set when a
280 	 * sync operation (i.e "data-check", "requested-resync", "resync",
281 	 * "recovery", or "reshape") is started.  It holds this value even
282 	 * when the sync thread is "frozen" (interrupted) or "idle" (stopped
283 	 * or finished).  It is overwritten when a new sync operation is begun.
284 	 */
285 	char				*last_sync_action;
286 	sector_t			curr_resync;	/* last block scheduled */
287 	/* As resync requests can complete out of order, we cannot easily track
288 	 * how much resync has been completed.  So we occasionally pause until
289 	 * everything completes, then set curr_resync_completed to curr_resync.
290 	 * As such it may be well behind the real resync mark, but it is a value
291 	 * we are certain of.
292 	 */
293 	sector_t			curr_resync_completed;
294 	unsigned long			resync_mark;	/* a recent timestamp */
295 	sector_t			resync_mark_cnt;/* blocks written at resync_mark */
296 	sector_t			curr_mark_cnt; /* blocks scheduled now */
297 
298 	sector_t			resync_max_sectors; /* may be set by personality */
299 
300 	atomic64_t			resync_mismatches; /* count of sectors where
301 							    * parity/replica mismatch found
302 							    */
303 
304 	/* allow user-space to request suspension of IO to regions of the array */
305 	sector_t			suspend_lo;
306 	sector_t			suspend_hi;
307 	/* if zero, use the system-wide default */
308 	int				sync_speed_min;
309 	int				sync_speed_max;
310 
311 	/* resync even though the same disks are shared among md-devices */
312 	int				parallel_resync;
313 
314 	int				ok_start_degraded;
315 	/* recovery/resync flags
316 	 * NEEDED:   we might need to start a resync/recover
317 	 * RUNNING:  a thread is running, or about to be started
318 	 * SYNC:     actually doing a resync, not a recovery
319 	 * RECOVER:  doing recovery, or need to try it.
320 	 * INTR:     resync needs to be aborted for some reason
321 	 * DONE:     thread is done and is waiting to be reaped
322 	 * REQUEST:  user-space has requested a sync (used with SYNC)
323 	 * CHECK:    user-space request for check-only, no repair
324 	 * RESHAPE:  A reshape is happening
325 	 * ERROR:    sync-action interrupted because io-error
326 	 *
327 	 * If neither SYNC or RESHAPE are set, then it is a recovery.
328 	 */
329 #define	MD_RECOVERY_RUNNING	0
330 #define	MD_RECOVERY_SYNC	1
331 #define	MD_RECOVERY_RECOVER	2
332 #define	MD_RECOVERY_INTR	3
333 #define	MD_RECOVERY_DONE	4
334 #define	MD_RECOVERY_NEEDED	5
335 #define	MD_RECOVERY_REQUESTED	6
336 #define	MD_RECOVERY_CHECK	7
337 #define MD_RECOVERY_RESHAPE	8
338 #define	MD_RECOVERY_FROZEN	9
339 #define	MD_RECOVERY_ERROR	10
340 
341 	unsigned long			recovery;
342 	/* If a RAID personality determines that recovery (of a particular
343 	 * device) will fail due to a read error on the source device, it
344 	 * takes a copy of this number and does not attempt recovery again
345 	 * until this number changes.
346 	 */
347 	int				recovery_disabled;
348 
349 	int				in_sync;	/* know to not need resync */
350 	/* 'open_mutex' avoids races between 'md_open' and 'do_md_stop', so
351 	 * that we are never stopping an array while it is open.
352 	 * 'reconfig_mutex' protects all other reconfiguration.
353 	 * These locks are separate due to conflicting interactions
354 	 * with bdev->bd_mutex.
355 	 * Lock ordering is:
356 	 *  reconfig_mutex -> bd_mutex : e.g. do_md_run -> revalidate_disk
357 	 *  bd_mutex -> open_mutex:  e.g. __blkdev_get -> md_open
358 	 */
359 	struct mutex			open_mutex;
360 	struct mutex			reconfig_mutex;
361 	atomic_t			active;		/* general refcount */
362 	atomic_t			openers;	/* number of active opens */
363 
364 	int				changed;	/* True if we might need to
365 							 * reread partition info */
366 	int				degraded;	/* whether md should consider
367 							 * adding a spare
368 							 */
369 	int				merge_check_needed; /* at least one
370 							     * member device
371 							     * has a
372 							     * merge_bvec_fn */
373 
374 	atomic_t			recovery_active; /* blocks scheduled, but not written */
375 	wait_queue_head_t		recovery_wait;
376 	sector_t			recovery_cp;
377 	sector_t			resync_min;	/* user requested sync
378 							 * starts here */
379 	sector_t			resync_max;	/* resync should pause
380 							 * when it gets here */
381 
382 	struct kernfs_node		*sysfs_state;	/* handle for 'array_state'
383 							 * file in sysfs.
384 							 */
385 	struct kernfs_node		*sysfs_action;  /* handle for 'sync_action' */
386 
387 	struct work_struct del_work;	/* used for delayed sysfs removal */
388 
389 	spinlock_t			write_lock;
390 	wait_queue_head_t		sb_wait;	/* for waiting on superblock updates */
391 	atomic_t			pending_writes;	/* number of active superblock writes */
392 
393 	unsigned int			safemode;	/* if set, update "clean" superblock
394 							 * when no writes pending.
395 							 */
396 	unsigned int			safemode_delay;
397 	struct timer_list		safemode_timer;
398 	atomic_t			writes_pending;
399 	struct request_queue		*queue;	/* for plugging ... */
400 
401 	struct bitmap			*bitmap; /* the bitmap for the device */
402 	struct {
403 		struct file		*file; /* the bitmap file */
404 		loff_t			offset; /* offset from superblock of
405 						 * start of bitmap. May be
406 						 * negative, but not '0'
407 						 * For external metadata, offset
408 						 * from start of device.
409 						 */
410 		unsigned long		space; /* space available at this offset */
411 		loff_t			default_offset; /* this is the offset to use when
412 							 * hot-adding a bitmap.  It should
413 							 * eventually be settable by sysfs.
414 							 */
415 		unsigned long		default_space; /* space available at
416 							* default offset */
417 		struct mutex		mutex;
418 		unsigned long		chunksize;
419 		unsigned long		daemon_sleep; /* how many jiffies between updates? */
420 		unsigned long		max_write_behind; /* write-behind mode */
421 		int			external;
422 	} bitmap_info;
423 
424 	atomic_t			max_corr_read_errors; /* max read retries */
425 	struct list_head		all_mddevs;
426 
427 	struct attribute_group		*to_remove;
428 
429 	struct bio_set			*bio_set;
430 
431 	/* Generic flush handling.
432 	 * The last to finish preflush schedules a worker to submit
433 	 * the rest of the request (without the REQ_FLUSH flag).
434 	 */
435 	struct bio *flush_bio;
436 	atomic_t flush_pending;
437 	struct work_struct flush_work;
438 	struct work_struct event_work;	/* used by dm to report failure event */
439 	void (*sync_super)(struct mddev *mddev, struct md_rdev *rdev);
440 };
441 
442 static inline void rdev_dec_pending(struct md_rdev *rdev, struct mddev *mddev)
443 {
444 	int faulty = test_bit(Faulty, &rdev->flags);
445 	if (atomic_dec_and_test(&rdev->nr_pending) && faulty)
446 		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
447 }
448 
449 static inline void md_sync_acct(struct block_device *bdev, unsigned long nr_sectors)
450 {
451 	atomic_add(nr_sectors, &bdev->bd_contains->bd_disk->sync_io);
452 }
453 
454 struct md_personality
455 {
456 	char *name;
457 	int level;
458 	struct list_head list;
459 	struct module *owner;
460 	void (*make_request)(struct mddev *mddev, struct bio *bio);
461 	int (*run)(struct mddev *mddev);
462 	int (*stop)(struct mddev *mddev);
463 	void (*status)(struct seq_file *seq, struct mddev *mddev);
464 	/* error_handler must set ->faulty and clear ->in_sync
465 	 * if appropriate, and should abort recovery if needed
466 	 */
467 	void (*error_handler)(struct mddev *mddev, struct md_rdev *rdev);
468 	int (*hot_add_disk) (struct mddev *mddev, struct md_rdev *rdev);
469 	int (*hot_remove_disk) (struct mddev *mddev, struct md_rdev *rdev);
470 	int (*spare_active) (struct mddev *mddev);
471 	sector_t (*sync_request)(struct mddev *mddev, sector_t sector_nr, int *skipped, int go_faster);
472 	int (*resize) (struct mddev *mddev, sector_t sectors);
473 	sector_t (*size) (struct mddev *mddev, sector_t sectors, int raid_disks);
474 	int (*check_reshape) (struct mddev *mddev);
475 	int (*start_reshape) (struct mddev *mddev);
476 	void (*finish_reshape) (struct mddev *mddev);
477 	/* quiesce moves between quiescence states
478 	 * 0 - fully active
479 	 * 1 - no new requests allowed
480 	 * others - reserved
481 	 */
482 	void (*quiesce) (struct mddev *mddev, int state);
483 	/* takeover is used to transition an array from one
484 	 * personality to another.  The new personality must be able
485 	 * to handle the data in the current layout.
486 	 * e.g. 2drive raid1 -> 2drive raid5
487 	 *      ndrive raid5 -> degraded n+1drive raid6 with special layout
488 	 * If the takeover succeeds, a new 'private' structure is returned.
489 	 * This needs to be installed and then ->run used to activate the
490 	 * array.
491 	 */
492 	void *(*takeover) (struct mddev *mddev);
493 };
494 
495 struct md_sysfs_entry {
496 	struct attribute attr;
497 	ssize_t (*show)(struct mddev *, char *);
498 	ssize_t (*store)(struct mddev *, const char *, size_t);
499 };
500 extern struct attribute_group md_bitmap_group;
501 
502 static inline struct kernfs_node *sysfs_get_dirent_safe(struct kernfs_node *sd, char *name)
503 {
504 	if (sd)
505 		return sysfs_get_dirent(sd, name);
506 	return sd;
507 }
508 static inline void sysfs_notify_dirent_safe(struct kernfs_node *sd)
509 {
510 	if (sd)
511 		sysfs_notify_dirent(sd);
512 }
513 
514 static inline char * mdname (struct mddev * mddev)
515 {
516 	return mddev->gendisk ? mddev->gendisk->disk_name : "mdX";
517 }
518 
519 static inline int sysfs_link_rdev(struct mddev *mddev, struct md_rdev *rdev)
520 {
521 	char nm[20];
522 	if (!test_bit(Replacement, &rdev->flags) && mddev->kobj.sd) {
523 		sprintf(nm, "rd%d", rdev->raid_disk);
524 		return sysfs_create_link(&mddev->kobj, &rdev->kobj, nm);
525 	} else
526 		return 0;
527 }
528 
529 static inline void sysfs_unlink_rdev(struct mddev *mddev, struct md_rdev *rdev)
530 {
531 	char nm[20];
532 	if (!test_bit(Replacement, &rdev->flags) && mddev->kobj.sd) {
533 		sprintf(nm, "rd%d", rdev->raid_disk);
534 		sysfs_remove_link(&mddev->kobj, nm);
535 	}
536 }
537 
538 /*
539  * iterates through some rdev ringlist. It's safe to remove the
540  * current 'rdev'. Dont touch 'tmp' though.
541  */
542 #define rdev_for_each_list(rdev, tmp, head)				\
543 	list_for_each_entry_safe(rdev, tmp, head, same_set)
544 
545 /*
546  * iterates through the 'same array disks' ringlist
547  */
548 #define rdev_for_each(rdev, mddev)				\
549 	list_for_each_entry(rdev, &((mddev)->disks), same_set)
550 
551 #define rdev_for_each_safe(rdev, tmp, mddev)				\
552 	list_for_each_entry_safe(rdev, tmp, &((mddev)->disks), same_set)
553 
554 #define rdev_for_each_rcu(rdev, mddev)				\
555 	list_for_each_entry_rcu(rdev, &((mddev)->disks), same_set)
556 
557 struct md_thread {
558 	void			(*run) (struct md_thread *thread);
559 	struct mddev		*mddev;
560 	wait_queue_head_t	wqueue;
561 	unsigned long		flags;
562 	struct task_struct	*tsk;
563 	unsigned long		timeout;
564 	void			*private;
565 };
566 
567 #define THREAD_WAKEUP  0
568 
569 static inline void safe_put_page(struct page *p)
570 {
571 	if (p) put_page(p);
572 }
573 
574 extern int register_md_personality(struct md_personality *p);
575 extern int unregister_md_personality(struct md_personality *p);
576 extern struct md_thread *md_register_thread(
577 	void (*run)(struct md_thread *thread),
578 	struct mddev *mddev,
579 	const char *name);
580 extern void md_unregister_thread(struct md_thread **threadp);
581 extern void md_wakeup_thread(struct md_thread *thread);
582 extern void md_check_recovery(struct mddev *mddev);
583 extern void md_reap_sync_thread(struct mddev *mddev);
584 extern void md_write_start(struct mddev *mddev, struct bio *bi);
585 extern void md_write_end(struct mddev *mddev);
586 extern void md_done_sync(struct mddev *mddev, int blocks, int ok);
587 extern void md_error(struct mddev *mddev, struct md_rdev *rdev);
588 extern void md_finish_reshape(struct mddev *mddev);
589 
590 extern int mddev_congested(struct mddev *mddev, int bits);
591 extern void md_flush_request(struct mddev *mddev, struct bio *bio);
592 extern void md_super_write(struct mddev *mddev, struct md_rdev *rdev,
593 			   sector_t sector, int size, struct page *page);
594 extern void md_super_wait(struct mddev *mddev);
595 extern int sync_page_io(struct md_rdev *rdev, sector_t sector, int size,
596 			struct page *page, int rw, bool metadata_op);
597 extern void md_do_sync(struct md_thread *thread);
598 extern void md_new_event(struct mddev *mddev);
599 extern int md_allow_write(struct mddev *mddev);
600 extern void md_wait_for_blocked_rdev(struct md_rdev *rdev, struct mddev *mddev);
601 extern void md_set_array_sectors(struct mddev *mddev, sector_t array_sectors);
602 extern int md_check_no_bitmap(struct mddev *mddev);
603 extern int md_integrity_register(struct mddev *mddev);
604 extern void md_integrity_add_rdev(struct md_rdev *rdev, struct mddev *mddev);
605 extern int strict_strtoul_scaled(const char *cp, unsigned long *res, int scale);
606 
607 extern void mddev_init(struct mddev *mddev);
608 extern int md_run(struct mddev *mddev);
609 extern void md_stop(struct mddev *mddev);
610 extern void md_stop_writes(struct mddev *mddev);
611 extern int md_rdev_init(struct md_rdev *rdev);
612 extern void md_rdev_clear(struct md_rdev *rdev);
613 
614 extern void mddev_suspend(struct mddev *mddev);
615 extern void mddev_resume(struct mddev *mddev);
616 extern struct bio *bio_clone_mddev(struct bio *bio, gfp_t gfp_mask,
617 				   struct mddev *mddev);
618 extern struct bio *bio_alloc_mddev(gfp_t gfp_mask, int nr_iovecs,
619 				   struct mddev *mddev);
620 
621 extern void md_unplug(struct blk_plug_cb *cb, bool from_schedule);
622 static inline int mddev_check_plugged(struct mddev *mddev)
623 {
624 	return !!blk_check_plugged(md_unplug, mddev,
625 				   sizeof(struct blk_plug_cb));
626 }
627 #endif /* _MD_MD_H */
628