xref: /linux/drivers/md/md.h (revision f79e4d5f92a129a1159c973735007d4ddc8541f3)
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/backing-dev.h>
20 #include <linux/badblocks.h>
21 #include <linux/kobject.h>
22 #include <linux/list.h>
23 #include <linux/mm.h>
24 #include <linux/mutex.h>
25 #include <linux/timer.h>
26 #include <linux/wait.h>
27 #include <linux/workqueue.h>
28 #include "md-cluster.h"
29 
30 #define MaxSector (~(sector_t)0)
31 
32 /*
33  * These flags should really be called "NO_RETRY" rather than
34  * "FAILFAST" because they don't make any promise about time lapse,
35  * only about the number of retries, which will be zero.
36  * REQ_FAILFAST_DRIVER is not included because
37  * Commit: 4a27446f3e39 ("[SCSI] modify scsi to handle new fail fast flags.")
38  * seems to suggest that the errors it avoids retrying should usually
39  * be retried.
40  */
41 #define	MD_FAILFAST	(REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT)
42 /*
43  * MD's 'extended' device
44  */
45 struct md_rdev {
46 	struct list_head same_set;	/* RAID devices within the same set */
47 
48 	sector_t sectors;		/* Device size (in 512bytes sectors) */
49 	struct mddev *mddev;		/* RAID array if running */
50 	int last_events;		/* IO event timestamp */
51 
52 	/*
53 	 * If meta_bdev is non-NULL, it means that a separate device is
54 	 * being used to store the metadata (superblock/bitmap) which
55 	 * would otherwise be contained on the same device as the data (bdev).
56 	 */
57 	struct block_device *meta_bdev;
58 	struct block_device *bdev;	/* block device handle */
59 
60 	struct page	*sb_page, *bb_page;
61 	int		sb_loaded;
62 	__u64		sb_events;
63 	sector_t	data_offset;	/* start of data in array */
64 	sector_t	new_data_offset;/* only relevant while reshaping */
65 	sector_t	sb_start;	/* offset of the super block (in 512byte sectors) */
66 	int		sb_size;	/* bytes in the superblock */
67 	int		preferred_minor;	/* autorun support */
68 
69 	struct kobject	kobj;
70 
71 	/* A device can be in one of three states based on two flags:
72 	 * Not working:   faulty==1 in_sync==0
73 	 * Fully working: faulty==0 in_sync==1
74 	 * Working, but not
75 	 * in sync with array
76 	 *                faulty==0 in_sync==0
77 	 *
78 	 * It can never have faulty==1, in_sync==1
79 	 * This reduces the burden of testing multiple flags in many cases
80 	 */
81 
82 	unsigned long	flags;	/* bit set of 'enum flag_bits' bits. */
83 	wait_queue_head_t blocked_wait;
84 
85 	int desc_nr;			/* descriptor index in the superblock */
86 	int raid_disk;			/* role of device in array */
87 	int new_raid_disk;		/* role that the device will have in
88 					 * the array after a level-change completes.
89 					 */
90 	int saved_raid_disk;		/* role that device used to have in the
91 					 * array and could again if we did a partial
92 					 * resync from the bitmap
93 					 */
94 	union {
95 		sector_t recovery_offset;/* If this device has been partially
96 					 * recovered, this is where we were
97 					 * up to.
98 					 */
99 		sector_t journal_tail;	/* If this device is a journal device,
100 					 * this is the journal tail (journal
101 					 * recovery start point)
102 					 */
103 	};
104 
105 	atomic_t	nr_pending;	/* number of pending requests.
106 					 * only maintained for arrays that
107 					 * support hot removal
108 					 */
109 	atomic_t	read_errors;	/* number of consecutive read errors that
110 					 * we have tried to ignore.
111 					 */
112 	time64_t	last_read_error;	/* monotonic time since our
113 						 * last read error
114 						 */
115 	atomic_t	corrected_errors; /* number of corrected read errors,
116 					   * for reporting to userspace and storing
117 					   * in superblock.
118 					   */
119 	struct work_struct del_work;	/* used for delayed sysfs removal */
120 
121 	struct kernfs_node *sysfs_state; /* handle for 'state'
122 					   * sysfs entry */
123 
124 	struct badblocks badblocks;
125 
126 	struct {
127 		short offset;	/* Offset from superblock to start of PPL.
128 				 * Not used by external metadata. */
129 		unsigned int size;	/* Size in sectors of the PPL space */
130 		sector_t sector;	/* First sector of the PPL space */
131 	} ppl;
132 };
133 enum flag_bits {
134 	Faulty,			/* device is known to have a fault */
135 	In_sync,		/* device is in_sync with rest of array */
136 	Bitmap_sync,		/* ..actually, not quite In_sync.  Need a
137 				 * bitmap-based recovery to get fully in sync.
138 				 * The bit is only meaningful before device
139 				 * has been passed to pers->hot_add_disk.
140 				 */
141 	WriteMostly,		/* Avoid reading if at all possible */
142 	AutoDetected,		/* added by auto-detect */
143 	Blocked,		/* An error occurred but has not yet
144 				 * been acknowledged by the metadata
145 				 * handler, so don't allow writes
146 				 * until it is cleared */
147 	WriteErrorSeen,		/* A write error has been seen on this
148 				 * device
149 				 */
150 	FaultRecorded,		/* Intermediate state for clearing
151 				 * Blocked.  The Fault is/will-be
152 				 * recorded in the metadata, but that
153 				 * metadata hasn't been stored safely
154 				 * on disk yet.
155 				 */
156 	BlockedBadBlocks,	/* A writer is blocked because they
157 				 * found an unacknowledged bad-block.
158 				 * This can safely be cleared at any
159 				 * time, and the writer will re-check.
160 				 * It may be set at any time, and at
161 				 * worst the writer will timeout and
162 				 * re-check.  So setting it as
163 				 * accurately as possible is good, but
164 				 * not absolutely critical.
165 				 */
166 	WantReplacement,	/* This device is a candidate to be
167 				 * hot-replaced, either because it has
168 				 * reported some faults, or because
169 				 * of explicit request.
170 				 */
171 	Replacement,		/* This device is a replacement for
172 				 * a want_replacement device with same
173 				 * raid_disk number.
174 				 */
175 	Candidate,		/* For clustered environments only:
176 				 * This device is seen locally but not
177 				 * by the whole cluster
178 				 */
179 	Journal,		/* This device is used as journal for
180 				 * raid-5/6.
181 				 * Usually, this device should be faster
182 				 * than other devices in the array
183 				 */
184 	ClusterRemove,
185 	RemoveSynchronized,	/* synchronize_rcu() was called after
186 				 * this device was known to be faulty,
187 				 * so it is safe to remove without
188 				 * another synchronize_rcu() call.
189 				 */
190 	ExternalBbl,            /* External metadata provides bad
191 				 * block management for a disk
192 				 */
193 	FailFast,		/* Minimal retries should be attempted on
194 				 * this device, so use REQ_FAILFAST_DEV.
195 				 * Also don't try to repair failed reads.
196 				 * It is expects that no bad block log
197 				 * is present.
198 				 */
199 	LastDev,		/* Seems to be the last working dev as
200 				 * it didn't fail, so don't use FailFast
201 				 * any more for metadata
202 				 */
203 };
204 
205 static inline int is_badblock(struct md_rdev *rdev, sector_t s, int sectors,
206 			      sector_t *first_bad, int *bad_sectors)
207 {
208 	if (unlikely(rdev->badblocks.count)) {
209 		int rv = badblocks_check(&rdev->badblocks, rdev->data_offset + s,
210 					sectors,
211 					first_bad, bad_sectors);
212 		if (rv)
213 			*first_bad -= rdev->data_offset;
214 		return rv;
215 	}
216 	return 0;
217 }
218 extern int rdev_set_badblocks(struct md_rdev *rdev, sector_t s, int sectors,
219 			      int is_new);
220 extern int rdev_clear_badblocks(struct md_rdev *rdev, sector_t s, int sectors,
221 				int is_new);
222 struct md_cluster_info;
223 
224 /* change UNSUPPORTED_MDDEV_FLAGS for each array type if new flag is added */
225 enum mddev_flags {
226 	MD_ARRAY_FIRST_USE,	/* First use of array, needs initialization */
227 	MD_CLOSING,		/* If set, we are closing the array, do not open
228 				 * it then */
229 	MD_JOURNAL_CLEAN,	/* A raid with journal is already clean */
230 	MD_HAS_JOURNAL,		/* The raid array has journal feature set */
231 	MD_CLUSTER_RESYNC_LOCKED, /* cluster raid only, which means node
232 				   * already took resync lock, need to
233 				   * release the lock */
234 	MD_FAILFAST_SUPPORTED,	/* Using MD_FAILFAST on metadata writes is
235 				 * supported as calls to md_error() will
236 				 * never cause the array to become failed.
237 				 */
238 	MD_HAS_PPL,		/* The raid array has PPL feature set */
239 	MD_HAS_MULTIPLE_PPLS,	/* The raid array has multiple PPLs feature set */
240 	MD_ALLOW_SB_UPDATE,	/* md_check_recovery is allowed to update
241 				 * the metadata without taking reconfig_mutex.
242 				 */
243 	MD_UPDATING_SB,		/* md_check_recovery is updating the metadata
244 				 * without explicitly holding reconfig_mutex.
245 				 */
246 };
247 
248 enum mddev_sb_flags {
249 	MD_SB_CHANGE_DEVS,		/* Some device status has changed */
250 	MD_SB_CHANGE_CLEAN,	/* transition to or from 'clean' */
251 	MD_SB_CHANGE_PENDING,	/* switch from 'clean' to 'active' in progress */
252 	MD_SB_NEED_REWRITE,	/* metadata write needs to be repeated */
253 };
254 
255 #define NR_FLUSH_INFOS 8
256 #define NR_FLUSH_BIOS 64
257 struct flush_info {
258 	struct bio			*bio;
259 	struct mddev			*mddev;
260 	struct work_struct		flush_work;
261 	atomic_t			flush_pending;
262 };
263 struct flush_bio {
264 	struct flush_info *fi;
265 	struct md_rdev *rdev;
266 };
267 
268 struct mddev {
269 	void				*private;
270 	struct md_personality		*pers;
271 	dev_t				unit;
272 	int				md_minor;
273 	struct list_head		disks;
274 	unsigned long			flags;
275 	unsigned long			sb_flags;
276 
277 	int				suspended;
278 	atomic_t			active_io;
279 	int				ro;
280 	int				sysfs_active; /* set when sysfs deletes
281 						       * are happening, so run/
282 						       * takeover/stop are not safe
283 						       */
284 	struct gendisk			*gendisk;
285 
286 	struct kobject			kobj;
287 	int				hold_active;
288 #define	UNTIL_IOCTL	1
289 #define	UNTIL_STOP	2
290 
291 	/* Superblock information */
292 	int				major_version,
293 					minor_version,
294 					patch_version;
295 	int				persistent;
296 	int				external;	/* metadata is
297 							 * managed externally */
298 	char				metadata_type[17]; /* externally set*/
299 	int				chunk_sectors;
300 	time64_t			ctime, utime;
301 	int				level, layout;
302 	char				clevel[16];
303 	int				raid_disks;
304 	int				max_disks;
305 	sector_t			dev_sectors;	/* used size of
306 							 * component devices */
307 	sector_t			array_sectors; /* exported array size */
308 	int				external_size; /* size managed
309 							* externally */
310 	__u64				events;
311 	/* If the last 'event' was simply a clean->dirty transition, and
312 	 * we didn't write it to the spares, then it is safe and simple
313 	 * to just decrement the event count on a dirty->clean transition.
314 	 * So we record that possibility here.
315 	 */
316 	int				can_decrease_events;
317 
318 	char				uuid[16];
319 
320 	/* If the array is being reshaped, we need to record the
321 	 * new shape and an indication of where we are up to.
322 	 * This is written to the superblock.
323 	 * If reshape_position is MaxSector, then no reshape is happening (yet).
324 	 */
325 	sector_t			reshape_position;
326 	int				delta_disks, new_level, new_layout;
327 	int				new_chunk_sectors;
328 	int				reshape_backwards;
329 
330 	struct md_thread		*thread;	/* management thread */
331 	struct md_thread		*sync_thread;	/* doing resync or reconstruct */
332 
333 	/* 'last_sync_action' is initialized to "none".  It is set when a
334 	 * sync operation (i.e "data-check", "requested-resync", "resync",
335 	 * "recovery", or "reshape") is started.  It holds this value even
336 	 * when the sync thread is "frozen" (interrupted) or "idle" (stopped
337 	 * or finished).  It is overwritten when a new sync operation is begun.
338 	 */
339 	char				*last_sync_action;
340 	sector_t			curr_resync;	/* last block scheduled */
341 	/* As resync requests can complete out of order, we cannot easily track
342 	 * how much resync has been completed.  So we occasionally pause until
343 	 * everything completes, then set curr_resync_completed to curr_resync.
344 	 * As such it may be well behind the real resync mark, but it is a value
345 	 * we are certain of.
346 	 */
347 	sector_t			curr_resync_completed;
348 	unsigned long			resync_mark;	/* a recent timestamp */
349 	sector_t			resync_mark_cnt;/* blocks written at resync_mark */
350 	sector_t			curr_mark_cnt; /* blocks scheduled now */
351 
352 	sector_t			resync_max_sectors; /* may be set by personality */
353 
354 	atomic64_t			resync_mismatches; /* count of sectors where
355 							    * parity/replica mismatch found
356 							    */
357 
358 	/* allow user-space to request suspension of IO to regions of the array */
359 	sector_t			suspend_lo;
360 	sector_t			suspend_hi;
361 	/* if zero, use the system-wide default */
362 	int				sync_speed_min;
363 	int				sync_speed_max;
364 
365 	/* resync even though the same disks are shared among md-devices */
366 	int				parallel_resync;
367 
368 	int				ok_start_degraded;
369 
370 	unsigned long			recovery;
371 	/* If a RAID personality determines that recovery (of a particular
372 	 * device) will fail due to a read error on the source device, it
373 	 * takes a copy of this number and does not attempt recovery again
374 	 * until this number changes.
375 	 */
376 	int				recovery_disabled;
377 
378 	int				in_sync;	/* know to not need resync */
379 	/* 'open_mutex' avoids races between 'md_open' and 'do_md_stop', so
380 	 * that we are never stopping an array while it is open.
381 	 * 'reconfig_mutex' protects all other reconfiguration.
382 	 * These locks are separate due to conflicting interactions
383 	 * with bdev->bd_mutex.
384 	 * Lock ordering is:
385 	 *  reconfig_mutex -> bd_mutex : e.g. do_md_run -> revalidate_disk
386 	 *  bd_mutex -> open_mutex:  e.g. __blkdev_get -> md_open
387 	 */
388 	struct mutex			open_mutex;
389 	struct mutex			reconfig_mutex;
390 	atomic_t			active;		/* general refcount */
391 	atomic_t			openers;	/* number of active opens */
392 
393 	int				changed;	/* True if we might need to
394 							 * reread partition info */
395 	int				degraded;	/* whether md should consider
396 							 * adding a spare
397 							 */
398 
399 	atomic_t			recovery_active; /* blocks scheduled, but not written */
400 	wait_queue_head_t		recovery_wait;
401 	sector_t			recovery_cp;
402 	sector_t			resync_min;	/* user requested sync
403 							 * starts here */
404 	sector_t			resync_max;	/* resync should pause
405 							 * when it gets here */
406 
407 	struct kernfs_node		*sysfs_state;	/* handle for 'array_state'
408 							 * file in sysfs.
409 							 */
410 	struct kernfs_node		*sysfs_action;  /* handle for 'sync_action' */
411 
412 	struct work_struct del_work;	/* used for delayed sysfs removal */
413 
414 	/* "lock" protects:
415 	 *   flush_bio transition from NULL to !NULL
416 	 *   rdev superblocks, events
417 	 *   clearing MD_CHANGE_*
418 	 *   in_sync - and related safemode and MD_CHANGE changes
419 	 *   pers (also protected by reconfig_mutex and pending IO).
420 	 *   clearing ->bitmap
421 	 *   clearing ->bitmap_info.file
422 	 *   changing ->resync_{min,max}
423 	 *   setting MD_RECOVERY_RUNNING (which interacts with resync_{min,max})
424 	 */
425 	spinlock_t			lock;
426 	wait_queue_head_t		sb_wait;	/* for waiting on superblock updates */
427 	atomic_t			pending_writes;	/* number of active superblock writes */
428 
429 	unsigned int			safemode;	/* if set, update "clean" superblock
430 							 * when no writes pending.
431 							 */
432 	unsigned int			safemode_delay;
433 	struct timer_list		safemode_timer;
434 	struct percpu_ref		writes_pending;
435 	int				sync_checkers;	/* # of threads checking writes_pending */
436 	struct request_queue		*queue;	/* for plugging ... */
437 
438 	struct bitmap			*bitmap; /* the bitmap for the device */
439 	struct {
440 		struct file		*file; /* the bitmap file */
441 		loff_t			offset; /* offset from superblock of
442 						 * start of bitmap. May be
443 						 * negative, but not '0'
444 						 * For external metadata, offset
445 						 * from start of device.
446 						 */
447 		unsigned long		space; /* space available at this offset */
448 		loff_t			default_offset; /* this is the offset to use when
449 							 * hot-adding a bitmap.  It should
450 							 * eventually be settable by sysfs.
451 							 */
452 		unsigned long		default_space; /* space available at
453 							* default offset */
454 		struct mutex		mutex;
455 		unsigned long		chunksize;
456 		unsigned long		daemon_sleep; /* how many jiffies between updates? */
457 		unsigned long		max_write_behind; /* write-behind mode */
458 		int			external;
459 		int			nodes; /* Maximum number of nodes in the cluster */
460 		char                    cluster_name[64]; /* Name of the cluster */
461 	} bitmap_info;
462 
463 	atomic_t			max_corr_read_errors; /* max read retries */
464 	struct list_head		all_mddevs;
465 
466 	struct attribute_group		*to_remove;
467 
468 	struct bio_set			bio_set;
469 	struct bio_set			sync_set; /* for sync operations like
470 						   * metadata and bitmap writes
471 						   */
472 
473 	mempool_t			*flush_pool;
474 	mempool_t			*flush_bio_pool;
475 	struct work_struct event_work;	/* used by dm to report failure event */
476 	void (*sync_super)(struct mddev *mddev, struct md_rdev *rdev);
477 	struct md_cluster_info		*cluster_info;
478 	unsigned int			good_device_nr;	/* good device num within cluster raid */
479 
480 	bool	has_superblocks:1;
481 };
482 
483 enum recovery_flags {
484 	/*
485 	 * If neither SYNC or RESHAPE are set, then it is a recovery.
486 	 */
487 	MD_RECOVERY_RUNNING,	/* a thread is running, or about to be started */
488 	MD_RECOVERY_SYNC,	/* actually doing a resync, not a recovery */
489 	MD_RECOVERY_RECOVER,	/* doing recovery, or need to try it. */
490 	MD_RECOVERY_INTR,	/* resync needs to be aborted for some reason */
491 	MD_RECOVERY_DONE,	/* thread is done and is waiting to be reaped */
492 	MD_RECOVERY_NEEDED,	/* we might need to start a resync/recover */
493 	MD_RECOVERY_REQUESTED,	/* user-space has requested a sync (used with SYNC) */
494 	MD_RECOVERY_CHECK,	/* user-space request for check-only, no repair */
495 	MD_RECOVERY_RESHAPE,	/* A reshape is happening */
496 	MD_RECOVERY_FROZEN,	/* User request to abort, and not restart, any action */
497 	MD_RECOVERY_ERROR,	/* sync-action interrupted because io-error */
498 	MD_RECOVERY_WAIT,	/* waiting for pers->start() to finish */
499 };
500 
501 static inline int __must_check mddev_lock(struct mddev *mddev)
502 {
503 	return mutex_lock_interruptible(&mddev->reconfig_mutex);
504 }
505 
506 /* Sometimes we need to take the lock in a situation where
507  * failure due to interrupts is not acceptable.
508  */
509 static inline void mddev_lock_nointr(struct mddev *mddev)
510 {
511 	mutex_lock(&mddev->reconfig_mutex);
512 }
513 
514 static inline int mddev_trylock(struct mddev *mddev)
515 {
516 	return mutex_trylock(&mddev->reconfig_mutex);
517 }
518 extern void mddev_unlock(struct mddev *mddev);
519 
520 static inline void md_sync_acct(struct block_device *bdev, unsigned long nr_sectors)
521 {
522 	atomic_add(nr_sectors, &bdev->bd_contains->bd_disk->sync_io);
523 }
524 
525 static inline void md_sync_acct_bio(struct bio *bio, unsigned long nr_sectors)
526 {
527 	atomic_add(nr_sectors, &bio->bi_disk->sync_io);
528 }
529 
530 struct md_personality
531 {
532 	char *name;
533 	int level;
534 	struct list_head list;
535 	struct module *owner;
536 	bool (*make_request)(struct mddev *mddev, struct bio *bio);
537 	/*
538 	 * start up works that do NOT require md_thread. tasks that
539 	 * requires md_thread should go into start()
540 	 */
541 	int (*run)(struct mddev *mddev);
542 	/* start up works that require md threads */
543 	int (*start)(struct mddev *mddev);
544 	void (*free)(struct mddev *mddev, void *priv);
545 	void (*status)(struct seq_file *seq, struct mddev *mddev);
546 	/* error_handler must set ->faulty and clear ->in_sync
547 	 * if appropriate, and should abort recovery if needed
548 	 */
549 	void (*error_handler)(struct mddev *mddev, struct md_rdev *rdev);
550 	int (*hot_add_disk) (struct mddev *mddev, struct md_rdev *rdev);
551 	int (*hot_remove_disk) (struct mddev *mddev, struct md_rdev *rdev);
552 	int (*spare_active) (struct mddev *mddev);
553 	sector_t (*sync_request)(struct mddev *mddev, sector_t sector_nr, int *skipped);
554 	int (*resize) (struct mddev *mddev, sector_t sectors);
555 	sector_t (*size) (struct mddev *mddev, sector_t sectors, int raid_disks);
556 	int (*check_reshape) (struct mddev *mddev);
557 	int (*start_reshape) (struct mddev *mddev);
558 	void (*finish_reshape) (struct mddev *mddev);
559 	/* quiesce suspends or resumes internal processing.
560 	 * 1 - stop new actions and wait for action io to complete
561 	 * 0 - return to normal behaviour
562 	 */
563 	void (*quiesce) (struct mddev *mddev, int quiesce);
564 	/* takeover is used to transition an array from one
565 	 * personality to another.  The new personality must be able
566 	 * to handle the data in the current layout.
567 	 * e.g. 2drive raid1 -> 2drive raid5
568 	 *      ndrive raid5 -> degraded n+1drive raid6 with special layout
569 	 * If the takeover succeeds, a new 'private' structure is returned.
570 	 * This needs to be installed and then ->run used to activate the
571 	 * array.
572 	 */
573 	void *(*takeover) (struct mddev *mddev);
574 	/* congested implements bdi.congested_fn().
575 	 * Will not be called while array is 'suspended' */
576 	int (*congested)(struct mddev *mddev, int bits);
577 	/* Changes the consistency policy of an active array. */
578 	int (*change_consistency_policy)(struct mddev *mddev, const char *buf);
579 };
580 
581 struct md_sysfs_entry {
582 	struct attribute attr;
583 	ssize_t (*show)(struct mddev *, char *);
584 	ssize_t (*store)(struct mddev *, const char *, size_t);
585 };
586 extern struct attribute_group md_bitmap_group;
587 
588 static inline struct kernfs_node *sysfs_get_dirent_safe(struct kernfs_node *sd, char *name)
589 {
590 	if (sd)
591 		return sysfs_get_dirent(sd, name);
592 	return sd;
593 }
594 static inline void sysfs_notify_dirent_safe(struct kernfs_node *sd)
595 {
596 	if (sd)
597 		sysfs_notify_dirent(sd);
598 }
599 
600 static inline char * mdname (struct mddev * mddev)
601 {
602 	return mddev->gendisk ? mddev->gendisk->disk_name : "mdX";
603 }
604 
605 static inline int sysfs_link_rdev(struct mddev *mddev, struct md_rdev *rdev)
606 {
607 	char nm[20];
608 	if (!test_bit(Replacement, &rdev->flags) &&
609 	    !test_bit(Journal, &rdev->flags) &&
610 	    mddev->kobj.sd) {
611 		sprintf(nm, "rd%d", rdev->raid_disk);
612 		return sysfs_create_link(&mddev->kobj, &rdev->kobj, nm);
613 	} else
614 		return 0;
615 }
616 
617 static inline void sysfs_unlink_rdev(struct mddev *mddev, struct md_rdev *rdev)
618 {
619 	char nm[20];
620 	if (!test_bit(Replacement, &rdev->flags) &&
621 	    !test_bit(Journal, &rdev->flags) &&
622 	    mddev->kobj.sd) {
623 		sprintf(nm, "rd%d", rdev->raid_disk);
624 		sysfs_remove_link(&mddev->kobj, nm);
625 	}
626 }
627 
628 /*
629  * iterates through some rdev ringlist. It's safe to remove the
630  * current 'rdev'. Dont touch 'tmp' though.
631  */
632 #define rdev_for_each_list(rdev, tmp, head)				\
633 	list_for_each_entry_safe(rdev, tmp, head, same_set)
634 
635 /*
636  * iterates through the 'same array disks' ringlist
637  */
638 #define rdev_for_each(rdev, mddev)				\
639 	list_for_each_entry(rdev, &((mddev)->disks), same_set)
640 
641 #define rdev_for_each_safe(rdev, tmp, mddev)				\
642 	list_for_each_entry_safe(rdev, tmp, &((mddev)->disks), same_set)
643 
644 #define rdev_for_each_rcu(rdev, mddev)				\
645 	list_for_each_entry_rcu(rdev, &((mddev)->disks), same_set)
646 
647 struct md_thread {
648 	void			(*run) (struct md_thread *thread);
649 	struct mddev		*mddev;
650 	wait_queue_head_t	wqueue;
651 	unsigned long		flags;
652 	struct task_struct	*tsk;
653 	unsigned long		timeout;
654 	void			*private;
655 };
656 
657 #define THREAD_WAKEUP  0
658 
659 static inline void safe_put_page(struct page *p)
660 {
661 	if (p) put_page(p);
662 }
663 
664 extern int register_md_personality(struct md_personality *p);
665 extern int unregister_md_personality(struct md_personality *p);
666 extern int register_md_cluster_operations(struct md_cluster_operations *ops,
667 		struct module *module);
668 extern int unregister_md_cluster_operations(void);
669 extern int md_setup_cluster(struct mddev *mddev, int nodes);
670 extern void md_cluster_stop(struct mddev *mddev);
671 extern struct md_thread *md_register_thread(
672 	void (*run)(struct md_thread *thread),
673 	struct mddev *mddev,
674 	const char *name);
675 extern void md_unregister_thread(struct md_thread **threadp);
676 extern void md_wakeup_thread(struct md_thread *thread);
677 extern void md_check_recovery(struct mddev *mddev);
678 extern void md_reap_sync_thread(struct mddev *mddev);
679 extern int mddev_init_writes_pending(struct mddev *mddev);
680 extern bool md_write_start(struct mddev *mddev, struct bio *bi);
681 extern void md_write_inc(struct mddev *mddev, struct bio *bi);
682 extern void md_write_end(struct mddev *mddev);
683 extern void md_done_sync(struct mddev *mddev, int blocks, int ok);
684 extern void md_error(struct mddev *mddev, struct md_rdev *rdev);
685 extern void md_finish_reshape(struct mddev *mddev);
686 
687 extern int mddev_congested(struct mddev *mddev, int bits);
688 extern void md_flush_request(struct mddev *mddev, struct bio *bio);
689 extern void md_super_write(struct mddev *mddev, struct md_rdev *rdev,
690 			   sector_t sector, int size, struct page *page);
691 extern int md_super_wait(struct mddev *mddev);
692 extern int sync_page_io(struct md_rdev *rdev, sector_t sector, int size,
693 			struct page *page, int op, int op_flags,
694 			bool metadata_op);
695 extern void md_do_sync(struct md_thread *thread);
696 extern void md_new_event(struct mddev *mddev);
697 extern void md_allow_write(struct mddev *mddev);
698 extern void md_wait_for_blocked_rdev(struct md_rdev *rdev, struct mddev *mddev);
699 extern void md_set_array_sectors(struct mddev *mddev, sector_t array_sectors);
700 extern int md_check_no_bitmap(struct mddev *mddev);
701 extern int md_integrity_register(struct mddev *mddev);
702 extern int md_integrity_add_rdev(struct md_rdev *rdev, struct mddev *mddev);
703 extern int strict_strtoul_scaled(const char *cp, unsigned long *res, int scale);
704 
705 extern void mddev_init(struct mddev *mddev);
706 extern int md_run(struct mddev *mddev);
707 extern int md_start(struct mddev *mddev);
708 extern void md_stop(struct mddev *mddev);
709 extern void md_stop_writes(struct mddev *mddev);
710 extern int md_rdev_init(struct md_rdev *rdev);
711 extern void md_rdev_clear(struct md_rdev *rdev);
712 
713 extern void md_handle_request(struct mddev *mddev, struct bio *bio);
714 extern void mddev_suspend(struct mddev *mddev);
715 extern void mddev_resume(struct mddev *mddev);
716 extern struct bio *bio_alloc_mddev(gfp_t gfp_mask, int nr_iovecs,
717 				   struct mddev *mddev);
718 
719 extern void md_reload_sb(struct mddev *mddev, int raid_disk);
720 extern void md_update_sb(struct mddev *mddev, int force);
721 extern void md_kick_rdev_from_array(struct md_rdev * rdev);
722 struct md_rdev *md_find_rdev_nr_rcu(struct mddev *mddev, int nr);
723 struct md_rdev *md_find_rdev_rcu(struct mddev *mddev, dev_t dev);
724 
725 static inline void rdev_dec_pending(struct md_rdev *rdev, struct mddev *mddev)
726 {
727 	int faulty = test_bit(Faulty, &rdev->flags);
728 	if (atomic_dec_and_test(&rdev->nr_pending) && faulty) {
729 		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
730 		md_wakeup_thread(mddev->thread);
731 	}
732 }
733 
734 extern struct md_cluster_operations *md_cluster_ops;
735 static inline int mddev_is_clustered(struct mddev *mddev)
736 {
737 	return mddev->cluster_info && mddev->bitmap_info.nodes > 1;
738 }
739 
740 /* clear unsupported mddev_flags */
741 static inline void mddev_clear_unsupported_flags(struct mddev *mddev,
742 	unsigned long unsupported_flags)
743 {
744 	mddev->flags &= ~unsupported_flags;
745 }
746 
747 static inline void mddev_check_writesame(struct mddev *mddev, struct bio *bio)
748 {
749 	if (bio_op(bio) == REQ_OP_WRITE_SAME &&
750 	    !bio->bi_disk->queue->limits.max_write_same_sectors)
751 		mddev->queue->limits.max_write_same_sectors = 0;
752 }
753 
754 static inline void mddev_check_write_zeroes(struct mddev *mddev, struct bio *bio)
755 {
756 	if (bio_op(bio) == REQ_OP_WRITE_ZEROES &&
757 	    !bio->bi_disk->queue->limits.max_write_zeroes_sectors)
758 		mddev->queue->limits.max_write_zeroes_sectors = 0;
759 }
760 #endif /* _MD_MD_H */
761