xref: /linux/drivers/md/md.h (revision 4413e16d9d21673bb5048a2e542f1aaa00015c2e)
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 sysfs_dirent *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 	Unmerged,		/* device is being added to array and should
133 				 * be considerred for bvec_merge_fn but not
134 				 * yet for actual IO
135 				 */
136 	WriteMostly,		/* Avoid reading if at all possible */
137 	AutoDetected,		/* added by auto-detect */
138 	Blocked,		/* An error occurred but has not yet
139 				 * been acknowledged by the metadata
140 				 * handler, so don't allow writes
141 				 * until it is cleared */
142 	WriteErrorSeen,		/* A write error has been seen on this
143 				 * device
144 				 */
145 	FaultRecorded,		/* Intermediate state for clearing
146 				 * Blocked.  The Fault is/will-be
147 				 * recorded in the metadata, but that
148 				 * metadata hasn't been stored safely
149 				 * on disk yet.
150 				 */
151 	BlockedBadBlocks,	/* A writer is blocked because they
152 				 * found an unacknowledged bad-block.
153 				 * This can safely be cleared at any
154 				 * time, and the writer will re-check.
155 				 * It may be set at any time, and at
156 				 * worst the writer will timeout and
157 				 * re-check.  So setting it as
158 				 * accurately as possible is good, but
159 				 * not absolutely critical.
160 				 */
161 	WantReplacement,	/* This device is a candidate to be
162 				 * hot-replaced, either because it has
163 				 * reported some faults, or because
164 				 * of explicit request.
165 				 */
166 	Replacement,		/* This device is a replacement for
167 				 * a want_replacement device with same
168 				 * raid_disk number.
169 				 */
170 };
171 
172 #define BB_LEN_MASK	(0x00000000000001FFULL)
173 #define BB_OFFSET_MASK	(0x7FFFFFFFFFFFFE00ULL)
174 #define BB_ACK_MASK	(0x8000000000000000ULL)
175 #define BB_MAX_LEN	512
176 #define BB_OFFSET(x)	(((x) & BB_OFFSET_MASK) >> 9)
177 #define BB_LEN(x)	(((x) & BB_LEN_MASK) + 1)
178 #define BB_ACK(x)	(!!((x) & BB_ACK_MASK))
179 #define BB_MAKE(a, l, ack) (((a)<<9) | ((l)-1) | ((u64)(!!(ack)) << 63))
180 
181 extern int md_is_badblock(struct badblocks *bb, sector_t s, int sectors,
182 			  sector_t *first_bad, int *bad_sectors);
183 static inline int is_badblock(struct md_rdev *rdev, sector_t s, int sectors,
184 			      sector_t *first_bad, int *bad_sectors)
185 {
186 	if (unlikely(rdev->badblocks.count)) {
187 		int rv = md_is_badblock(&rdev->badblocks, rdev->data_offset + s,
188 					sectors,
189 					first_bad, bad_sectors);
190 		if (rv)
191 			*first_bad -= rdev->data_offset;
192 		return rv;
193 	}
194 	return 0;
195 }
196 extern int rdev_set_badblocks(struct md_rdev *rdev, sector_t s, int sectors,
197 			      int is_new);
198 extern int rdev_clear_badblocks(struct md_rdev *rdev, sector_t s, int sectors,
199 				int is_new);
200 extern void md_ack_all_badblocks(struct badblocks *bb);
201 
202 struct mddev {
203 	void				*private;
204 	struct md_personality		*pers;
205 	dev_t				unit;
206 	int				md_minor;
207 	struct list_head 		disks;
208 	unsigned long			flags;
209 #define MD_CHANGE_DEVS	0	/* Some device status has changed */
210 #define MD_CHANGE_CLEAN 1	/* transition to or from 'clean' */
211 #define MD_CHANGE_PENDING 2	/* switch from 'clean' to 'active' in progress */
212 #define MD_ARRAY_FIRST_USE 3    /* First use of array, needs initialization */
213 
214 	int				suspended;
215 	atomic_t			active_io;
216 	int				ro;
217 	int				sysfs_active; /* set when sysfs deletes
218 						       * are happening, so run/
219 						       * takeover/stop are not safe
220 						       */
221 	int				ready; /* See when safe to pass
222 						* IO requests down */
223 	struct gendisk			*gendisk;
224 
225 	struct kobject			kobj;
226 	int				hold_active;
227 #define	UNTIL_IOCTL	1
228 #define	UNTIL_STOP	2
229 
230 	/* Superblock information */
231 	int				major_version,
232 					minor_version,
233 					patch_version;
234 	int				persistent;
235 	int 				external;	/* metadata is
236 							 * managed externally */
237 	char				metadata_type[17]; /* externally set*/
238 	int				chunk_sectors;
239 	time_t				ctime, utime;
240 	int				level, layout;
241 	char				clevel[16];
242 	int				raid_disks;
243 	int				max_disks;
244 	sector_t			dev_sectors; 	/* used size of
245 							 * component devices */
246 	sector_t			array_sectors; /* exported array size */
247 	int				external_size; /* size managed
248 							* externally */
249 	__u64				events;
250 	/* If the last 'event' was simply a clean->dirty transition, and
251 	 * we didn't write it to the spares, then it is safe and simple
252 	 * to just decrement the event count on a dirty->clean transition.
253 	 * So we record that possibility here.
254 	 */
255 	int				can_decrease_events;
256 
257 	char				uuid[16];
258 
259 	/* If the array is being reshaped, we need to record the
260 	 * new shape and an indication of where we are up to.
261 	 * This is written to the superblock.
262 	 * If reshape_position is MaxSector, then no reshape is happening (yet).
263 	 */
264 	sector_t			reshape_position;
265 	int				delta_disks, new_level, new_layout;
266 	int				new_chunk_sectors;
267 	int				reshape_backwards;
268 
269 	struct md_thread		*thread;	/* management thread */
270 	struct md_thread		*sync_thread;	/* doing resync or reconstruct */
271 	sector_t			curr_resync;	/* last block scheduled */
272 	/* As resync requests can complete out of order, we cannot easily track
273 	 * how much resync has been completed.  So we occasionally pause until
274 	 * everything completes, then set curr_resync_completed to curr_resync.
275 	 * As such it may be well behind the real resync mark, but it is a value
276 	 * we are certain of.
277 	 */
278 	sector_t			curr_resync_completed;
279 	unsigned long			resync_mark;	/* a recent timestamp */
280 	sector_t			resync_mark_cnt;/* blocks written at resync_mark */
281 	sector_t			curr_mark_cnt; /* blocks scheduled now */
282 
283 	sector_t			resync_max_sectors; /* may be set by personality */
284 
285 	sector_t			resync_mismatches; /* count of sectors where
286 							    * parity/replica mismatch found
287 							    */
288 
289 	/* allow user-space to request suspension of IO to regions of the array */
290 	sector_t			suspend_lo;
291 	sector_t			suspend_hi;
292 	/* if zero, use the system-wide default */
293 	int				sync_speed_min;
294 	int				sync_speed_max;
295 
296 	/* resync even though the same disks are shared among md-devices */
297 	int				parallel_resync;
298 
299 	int				ok_start_degraded;
300 	/* recovery/resync flags
301 	 * NEEDED:   we might need to start a resync/recover
302 	 * RUNNING:  a thread is running, or about to be started
303 	 * SYNC:     actually doing a resync, not a recovery
304 	 * RECOVER:  doing recovery, or need to try it.
305 	 * INTR:     resync needs to be aborted for some reason
306 	 * DONE:     thread is done and is waiting to be reaped
307 	 * REQUEST:  user-space has requested a sync (used with SYNC)
308 	 * CHECK:    user-space request for check-only, no repair
309 	 * RESHAPE:  A reshape is happening
310 	 *
311 	 * If neither SYNC or RESHAPE are set, then it is a recovery.
312 	 */
313 #define	MD_RECOVERY_RUNNING	0
314 #define	MD_RECOVERY_SYNC	1
315 #define	MD_RECOVERY_RECOVER	2
316 #define	MD_RECOVERY_INTR	3
317 #define	MD_RECOVERY_DONE	4
318 #define	MD_RECOVERY_NEEDED	5
319 #define	MD_RECOVERY_REQUESTED	6
320 #define	MD_RECOVERY_CHECK	7
321 #define MD_RECOVERY_RESHAPE	8
322 #define	MD_RECOVERY_FROZEN	9
323 
324 	unsigned long			recovery;
325 	/* If a RAID personality determines that recovery (of a particular
326 	 * device) will fail due to a read error on the source device, it
327 	 * takes a copy of this number and does not attempt recovery again
328 	 * until this number changes.
329 	 */
330 	int				recovery_disabled;
331 
332 	int				in_sync;	/* know to not need resync */
333 	/* 'open_mutex' avoids races between 'md_open' and 'do_md_stop', so
334 	 * that we are never stopping an array while it is open.
335 	 * 'reconfig_mutex' protects all other reconfiguration.
336 	 * These locks are separate due to conflicting interactions
337 	 * with bdev->bd_mutex.
338 	 * Lock ordering is:
339 	 *  reconfig_mutex -> bd_mutex : e.g. do_md_run -> revalidate_disk
340 	 *  bd_mutex -> open_mutex:  e.g. __blkdev_get -> md_open
341 	 */
342 	struct mutex			open_mutex;
343 	struct mutex			reconfig_mutex;
344 	atomic_t			active;		/* general refcount */
345 	atomic_t			openers;	/* number of active opens */
346 
347 	int				changed;	/* True if we might need to
348 							 * reread partition info */
349 	int				degraded;	/* whether md should consider
350 							 * adding a spare
351 							 */
352 	int				merge_check_needed; /* at least one
353 							     * member device
354 							     * has a
355 							     * merge_bvec_fn */
356 
357 	atomic_t			recovery_active; /* blocks scheduled, but not written */
358 	wait_queue_head_t		recovery_wait;
359 	sector_t			recovery_cp;
360 	sector_t			resync_min;	/* user requested sync
361 							 * starts here */
362 	sector_t			resync_max;	/* resync should pause
363 							 * when it gets here */
364 
365 	struct sysfs_dirent		*sysfs_state;	/* handle for 'array_state'
366 							 * file in sysfs.
367 							 */
368 	struct sysfs_dirent		*sysfs_action;  /* handle for 'sync_action' */
369 
370 	struct work_struct del_work;	/* used for delayed sysfs removal */
371 
372 	spinlock_t			write_lock;
373 	wait_queue_head_t		sb_wait;	/* for waiting on superblock updates */
374 	atomic_t			pending_writes;	/* number of active superblock writes */
375 
376 	unsigned int			safemode;	/* if set, update "clean" superblock
377 							 * when no writes pending.
378 							 */
379 	unsigned int			safemode_delay;
380 	struct timer_list		safemode_timer;
381 	atomic_t			writes_pending;
382 	struct request_queue		*queue;	/* for plugging ... */
383 
384 	struct bitmap                   *bitmap; /* the bitmap for the device */
385 	struct {
386 		struct file		*file; /* the bitmap file */
387 		loff_t			offset; /* offset from superblock of
388 						 * start of bitmap. May be
389 						 * negative, but not '0'
390 						 * For external metadata, offset
391 						 * from start of device.
392 						 */
393 		unsigned long		space; /* space available at this offset */
394 		loff_t			default_offset; /* this is the offset to use when
395 							 * hot-adding a bitmap.  It should
396 							 * eventually be settable by sysfs.
397 							 */
398 		unsigned long		default_space; /* space available at
399 							* default offset */
400 		struct mutex		mutex;
401 		unsigned long		chunksize;
402 		unsigned long		daemon_sleep; /* how many jiffies between updates? */
403 		unsigned long		max_write_behind; /* write-behind mode */
404 		int			external;
405 	} bitmap_info;
406 
407 	atomic_t 			max_corr_read_errors; /* max read retries */
408 	struct list_head		all_mddevs;
409 
410 	struct attribute_group		*to_remove;
411 
412 	struct bio_set			*bio_set;
413 
414 	/* Generic flush handling.
415 	 * The last to finish preflush schedules a worker to submit
416 	 * the rest of the request (without the REQ_FLUSH flag).
417 	 */
418 	struct bio *flush_bio;
419 	atomic_t flush_pending;
420 	struct work_struct flush_work;
421 	struct work_struct event_work;	/* used by dm to report failure event */
422 	void (*sync_super)(struct mddev *mddev, struct md_rdev *rdev);
423 };
424 
425 
426 static inline void rdev_dec_pending(struct md_rdev *rdev, struct mddev *mddev)
427 {
428 	int faulty = test_bit(Faulty, &rdev->flags);
429 	if (atomic_dec_and_test(&rdev->nr_pending) && faulty)
430 		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
431 }
432 
433 static inline void md_sync_acct(struct block_device *bdev, unsigned long nr_sectors)
434 {
435         atomic_add(nr_sectors, &bdev->bd_contains->bd_disk->sync_io);
436 }
437 
438 struct md_personality
439 {
440 	char *name;
441 	int level;
442 	struct list_head list;
443 	struct module *owner;
444 	void (*make_request)(struct mddev *mddev, struct bio *bio);
445 	int (*run)(struct mddev *mddev);
446 	int (*stop)(struct mddev *mddev);
447 	void (*status)(struct seq_file *seq, struct mddev *mddev);
448 	/* error_handler must set ->faulty and clear ->in_sync
449 	 * if appropriate, and should abort recovery if needed
450 	 */
451 	void (*error_handler)(struct mddev *mddev, struct md_rdev *rdev);
452 	int (*hot_add_disk) (struct mddev *mddev, struct md_rdev *rdev);
453 	int (*hot_remove_disk) (struct mddev *mddev, struct md_rdev *rdev);
454 	int (*spare_active) (struct mddev *mddev);
455 	sector_t (*sync_request)(struct mddev *mddev, sector_t sector_nr, int *skipped, int go_faster);
456 	int (*resize) (struct mddev *mddev, sector_t sectors);
457 	sector_t (*size) (struct mddev *mddev, sector_t sectors, int raid_disks);
458 	int (*check_reshape) (struct mddev *mddev);
459 	int (*start_reshape) (struct mddev *mddev);
460 	void (*finish_reshape) (struct mddev *mddev);
461 	/* quiesce moves between quiescence states
462 	 * 0 - fully active
463 	 * 1 - no new requests allowed
464 	 * others - reserved
465 	 */
466 	void (*quiesce) (struct mddev *mddev, int state);
467 	/* takeover is used to transition an array from one
468 	 * personality to another.  The new personality must be able
469 	 * to handle the data in the current layout.
470 	 * e.g. 2drive raid1 -> 2drive raid5
471 	 *      ndrive raid5 -> degraded n+1drive raid6 with special layout
472 	 * If the takeover succeeds, a new 'private' structure is returned.
473 	 * This needs to be installed and then ->run used to activate the
474 	 * array.
475 	 */
476 	void *(*takeover) (struct mddev *mddev);
477 };
478 
479 
480 struct md_sysfs_entry {
481 	struct attribute attr;
482 	ssize_t (*show)(struct mddev *, char *);
483 	ssize_t (*store)(struct mddev *, const char *, size_t);
484 };
485 extern struct attribute_group md_bitmap_group;
486 
487 static inline struct sysfs_dirent *sysfs_get_dirent_safe(struct sysfs_dirent *sd, char *name)
488 {
489 	if (sd)
490 		return sysfs_get_dirent(sd, NULL, name);
491 	return sd;
492 }
493 static inline void sysfs_notify_dirent_safe(struct sysfs_dirent *sd)
494 {
495 	if (sd)
496 		sysfs_notify_dirent(sd);
497 }
498 
499 static inline char * mdname (struct mddev * mddev)
500 {
501 	return mddev->gendisk ? mddev->gendisk->disk_name : "mdX";
502 }
503 
504 static inline int sysfs_link_rdev(struct mddev *mddev, struct md_rdev *rdev)
505 {
506 	char nm[20];
507 	if (!test_bit(Replacement, &rdev->flags)) {
508 		sprintf(nm, "rd%d", rdev->raid_disk);
509 		return sysfs_create_link(&mddev->kobj, &rdev->kobj, nm);
510 	} else
511 		return 0;
512 }
513 
514 static inline void sysfs_unlink_rdev(struct mddev *mddev, struct md_rdev *rdev)
515 {
516 	char nm[20];
517 	if (!test_bit(Replacement, &rdev->flags)) {
518 		sprintf(nm, "rd%d", rdev->raid_disk);
519 		sysfs_remove_link(&mddev->kobj, nm);
520 	}
521 }
522 
523 /*
524  * iterates through some rdev ringlist. It's safe to remove the
525  * current 'rdev'. Dont touch 'tmp' though.
526  */
527 #define rdev_for_each_list(rdev, tmp, head)				\
528 	list_for_each_entry_safe(rdev, tmp, head, same_set)
529 
530 /*
531  * iterates through the 'same array disks' ringlist
532  */
533 #define rdev_for_each(rdev, mddev)				\
534 	list_for_each_entry(rdev, &((mddev)->disks), same_set)
535 
536 #define rdev_for_each_safe(rdev, tmp, mddev)				\
537 	list_for_each_entry_safe(rdev, tmp, &((mddev)->disks), same_set)
538 
539 #define rdev_for_each_rcu(rdev, mddev)				\
540 	list_for_each_entry_rcu(rdev, &((mddev)->disks), same_set)
541 
542 struct md_thread {
543 	void			(*run) (struct mddev *mddev);
544 	struct mddev		*mddev;
545 	wait_queue_head_t	wqueue;
546 	unsigned long           flags;
547 	struct task_struct	*tsk;
548 	unsigned long		timeout;
549 };
550 
551 #define THREAD_WAKEUP  0
552 
553 #define __wait_event_lock_irq(wq, condition, lock, cmd) 		\
554 do {									\
555 	wait_queue_t __wait;						\
556 	init_waitqueue_entry(&__wait, current);				\
557 									\
558 	add_wait_queue(&wq, &__wait);					\
559 	for (;;) {							\
560 		set_current_state(TASK_UNINTERRUPTIBLE);		\
561 		if (condition)						\
562 			break;						\
563 		spin_unlock_irq(&lock);					\
564 		cmd;							\
565 		schedule();						\
566 		spin_lock_irq(&lock);					\
567 	}								\
568 	current->state = TASK_RUNNING;					\
569 	remove_wait_queue(&wq, &__wait);				\
570 } while (0)
571 
572 #define wait_event_lock_irq(wq, condition, lock, cmd) 			\
573 do {									\
574 	if (condition)	 						\
575 		break;							\
576 	__wait_event_lock_irq(wq, condition, lock, cmd);		\
577 } while (0)
578 
579 static inline void safe_put_page(struct page *p)
580 {
581 	if (p) put_page(p);
582 }
583 
584 extern int register_md_personality(struct md_personality *p);
585 extern int unregister_md_personality(struct md_personality *p);
586 extern struct md_thread *md_register_thread(
587 	void (*run)(struct mddev *mddev),
588 	struct mddev *mddev,
589 	const char *name);
590 extern void md_unregister_thread(struct md_thread **threadp);
591 extern void md_wakeup_thread(struct md_thread *thread);
592 extern void md_check_recovery(struct mddev *mddev);
593 extern void md_write_start(struct mddev *mddev, struct bio *bi);
594 extern void md_write_end(struct mddev *mddev);
595 extern void md_done_sync(struct mddev *mddev, int blocks, int ok);
596 extern void md_error(struct mddev *mddev, struct md_rdev *rdev);
597 extern void md_finish_reshape(struct mddev *mddev);
598 
599 extern int mddev_congested(struct mddev *mddev, int bits);
600 extern void md_flush_request(struct mddev *mddev, struct bio *bio);
601 extern void md_super_write(struct mddev *mddev, struct md_rdev *rdev,
602 			   sector_t sector, int size, struct page *page);
603 extern void md_super_wait(struct mddev *mddev);
604 extern int sync_page_io(struct md_rdev *rdev, sector_t sector, int size,
605 			struct page *page, int rw, bool metadata_op);
606 extern void md_do_sync(struct mddev *mddev);
607 extern void md_new_event(struct mddev *mddev);
608 extern int md_allow_write(struct mddev *mddev);
609 extern void md_wait_for_blocked_rdev(struct md_rdev *rdev, struct mddev *mddev);
610 extern void md_set_array_sectors(struct mddev *mddev, sector_t array_sectors);
611 extern int md_check_no_bitmap(struct mddev *mddev);
612 extern int md_integrity_register(struct mddev *mddev);
613 extern void md_integrity_add_rdev(struct md_rdev *rdev, struct mddev *mddev);
614 extern int strict_strtoul_scaled(const char *cp, unsigned long *res, int scale);
615 extern void restore_bitmap_write_access(struct file *file);
616 
617 extern void mddev_init(struct mddev *mddev);
618 extern int md_run(struct mddev *mddev);
619 extern void md_stop(struct mddev *mddev);
620 extern void md_stop_writes(struct mddev *mddev);
621 extern int md_rdev_init(struct md_rdev *rdev);
622 extern void md_rdev_clear(struct md_rdev *rdev);
623 
624 extern void mddev_suspend(struct mddev *mddev);
625 extern void mddev_resume(struct mddev *mddev);
626 extern struct bio *bio_clone_mddev(struct bio *bio, gfp_t gfp_mask,
627 				   struct mddev *mddev);
628 extern struct bio *bio_alloc_mddev(gfp_t gfp_mask, int nr_iovecs,
629 				   struct mddev *mddev);
630 extern void md_trim_bio(struct bio *bio, int offset, int size);
631 
632 extern void md_unplug(struct blk_plug_cb *cb, bool from_schedule);
633 static inline int mddev_check_plugged(struct mddev *mddev)
634 {
635 	return !!blk_check_plugged(md_unplug, mddev,
636 				   sizeof(struct blk_plug_cb));
637 }
638 #endif /* _MD_MD_H */
639