xref: /openbmc/linux/drivers/md/md.h (revision 81de3bf3)
1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 /*
3    md.h : kernel internal structure of the Linux MD driver
4           Copyright (C) 1996-98 Ingo Molnar, Gadi Oxman
5 
6 */
7 
8 #ifndef _MD_MD_H
9 #define _MD_MD_H
10 
11 #include <linux/blkdev.h>
12 #include <linux/backing-dev.h>
13 #include <linux/badblocks.h>
14 #include <linux/kobject.h>
15 #include <linux/list.h>
16 #include <linux/mm.h>
17 #include <linux/mutex.h>
18 #include <linux/timer.h>
19 #include <linux/wait.h>
20 #include <linux/workqueue.h>
21 #include "md-cluster.h"
22 
23 #define MaxSector (~(sector_t)0)
24 
25 /*
26  * These flags should really be called "NO_RETRY" rather than
27  * "FAILFAST" because they don't make any promise about time lapse,
28  * only about the number of retries, which will be zero.
29  * REQ_FAILFAST_DRIVER is not included because
30  * Commit: 4a27446f3e39 ("[SCSI] modify scsi to handle new fail fast flags.")
31  * seems to suggest that the errors it avoids retrying should usually
32  * be retried.
33  */
34 #define	MD_FAILFAST	(REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT)
35 /*
36  * MD's 'extended' device
37  */
38 struct md_rdev {
39 	struct list_head same_set;	/* RAID devices within the same set */
40 
41 	sector_t sectors;		/* Device size (in 512bytes sectors) */
42 	struct mddev *mddev;		/* RAID array if running */
43 	int last_events;		/* IO event timestamp */
44 
45 	/*
46 	 * If meta_bdev is non-NULL, it means that a separate device is
47 	 * being used to store the metadata (superblock/bitmap) which
48 	 * would otherwise be contained on the same device as the data (bdev).
49 	 */
50 	struct block_device *meta_bdev;
51 	struct block_device *bdev;	/* block device handle */
52 
53 	struct page	*sb_page, *bb_page;
54 	int		sb_loaded;
55 	__u64		sb_events;
56 	sector_t	data_offset;	/* start of data in array */
57 	sector_t	new_data_offset;/* only relevant while reshaping */
58 	sector_t	sb_start;	/* offset of the super block (in 512byte sectors) */
59 	int		sb_size;	/* bytes in the superblock */
60 	int		preferred_minor;	/* autorun support */
61 
62 	struct kobject	kobj;
63 
64 	/* A device can be in one of three states based on two flags:
65 	 * Not working:   faulty==1 in_sync==0
66 	 * Fully working: faulty==0 in_sync==1
67 	 * Working, but not
68 	 * in sync with array
69 	 *                faulty==0 in_sync==0
70 	 *
71 	 * It can never have faulty==1, in_sync==1
72 	 * This reduces the burden of testing multiple flags in many cases
73 	 */
74 
75 	unsigned long	flags;	/* bit set of 'enum flag_bits' bits. */
76 	wait_queue_head_t blocked_wait;
77 
78 	int desc_nr;			/* descriptor index in the superblock */
79 	int raid_disk;			/* role of device in array */
80 	int new_raid_disk;		/* role that the device will have in
81 					 * the array after a level-change completes.
82 					 */
83 	int saved_raid_disk;		/* role that device used to have in the
84 					 * array and could again if we did a partial
85 					 * resync from the bitmap
86 					 */
87 	union {
88 		sector_t recovery_offset;/* If this device has been partially
89 					 * recovered, this is where we were
90 					 * up to.
91 					 */
92 		sector_t journal_tail;	/* If this device is a journal device,
93 					 * this is the journal tail (journal
94 					 * recovery start point)
95 					 */
96 	};
97 
98 	atomic_t	nr_pending;	/* number of pending requests.
99 					 * only maintained for arrays that
100 					 * support hot removal
101 					 */
102 	atomic_t	read_errors;	/* number of consecutive read errors that
103 					 * we have tried to ignore.
104 					 */
105 	time64_t	last_read_error;	/* monotonic time since our
106 						 * last read error
107 						 */
108 	atomic_t	corrected_errors; /* number of corrected read errors,
109 					   * for reporting to userspace and storing
110 					   * in superblock.
111 					   */
112 
113 	/*
114 	 * The members for check collision of write behind IOs.
115 	 */
116 	struct list_head wb_list;
117 	spinlock_t wb_list_lock;
118 	wait_queue_head_t wb_io_wait;
119 
120 	struct work_struct del_work;	/* used for delayed sysfs removal */
121 
122 	struct kernfs_node *sysfs_state; /* handle for 'state'
123 					   * sysfs entry */
124 
125 	struct badblocks badblocks;
126 
127 	struct {
128 		short offset;	/* Offset from superblock to start of PPL.
129 				 * Not used by external metadata. */
130 		unsigned int size;	/* Size in sectors of the PPL space */
131 		sector_t sector;	/* First sector of the PPL space */
132 	} ppl;
133 };
134 enum flag_bits {
135 	Faulty,			/* device is known to have a fault */
136 	In_sync,		/* device is in_sync with rest of array */
137 	Bitmap_sync,		/* ..actually, not quite In_sync.  Need a
138 				 * bitmap-based recovery to get fully in sync.
139 				 * The bit is only meaningful before device
140 				 * has been passed to pers->hot_add_disk.
141 				 */
142 	WriteMostly,		/* Avoid reading if at all possible */
143 	AutoDetected,		/* added by auto-detect */
144 	Blocked,		/* An error occurred but has not yet
145 				 * been acknowledged by the metadata
146 				 * handler, so don't allow writes
147 				 * until it is cleared */
148 	WriteErrorSeen,		/* A write error has been seen on this
149 				 * device
150 				 */
151 	FaultRecorded,		/* Intermediate state for clearing
152 				 * Blocked.  The Fault is/will-be
153 				 * recorded in the metadata, but that
154 				 * metadata hasn't been stored safely
155 				 * on disk yet.
156 				 */
157 	BlockedBadBlocks,	/* A writer is blocked because they
158 				 * found an unacknowledged bad-block.
159 				 * This can safely be cleared at any
160 				 * time, and the writer will re-check.
161 				 * It may be set at any time, and at
162 				 * worst the writer will timeout and
163 				 * re-check.  So setting it as
164 				 * accurately as possible is good, but
165 				 * not absolutely critical.
166 				 */
167 	WantReplacement,	/* This device is a candidate to be
168 				 * hot-replaced, either because it has
169 				 * reported some faults, or because
170 				 * of explicit request.
171 				 */
172 	Replacement,		/* This device is a replacement for
173 				 * a want_replacement device with same
174 				 * raid_disk number.
175 				 */
176 	Candidate,		/* For clustered environments only:
177 				 * This device is seen locally but not
178 				 * by the whole cluster
179 				 */
180 	Journal,		/* This device is used as journal for
181 				 * raid-5/6.
182 				 * Usually, this device should be faster
183 				 * than other devices in the array
184 				 */
185 	ClusterRemove,
186 	RemoveSynchronized,	/* synchronize_rcu() was called after
187 				 * this device was known to be faulty,
188 				 * so it is safe to remove without
189 				 * another synchronize_rcu() call.
190 				 */
191 	ExternalBbl,            /* External metadata provides bad
192 				 * block management for a disk
193 				 */
194 	FailFast,		/* Minimal retries should be attempted on
195 				 * this device, so use REQ_FAILFAST_DEV.
196 				 * Also don't try to repair failed reads.
197 				 * It is expects that no bad block log
198 				 * is present.
199 				 */
200 	LastDev,		/* Seems to be the last working dev as
201 				 * it didn't fail, so don't use FailFast
202 				 * any more for metadata
203 				 */
204 	WBCollisionCheck,	/*
205 				 * multiqueue device should check if there
206 				 * is collision between write behind bios.
207 				 */
208 };
209 
210 static inline int is_badblock(struct md_rdev *rdev, sector_t s, int sectors,
211 			      sector_t *first_bad, int *bad_sectors)
212 {
213 	if (unlikely(rdev->badblocks.count)) {
214 		int rv = badblocks_check(&rdev->badblocks, rdev->data_offset + s,
215 					sectors,
216 					first_bad, bad_sectors);
217 		if (rv)
218 			*first_bad -= rdev->data_offset;
219 		return rv;
220 	}
221 	return 0;
222 }
223 extern int rdev_set_badblocks(struct md_rdev *rdev, sector_t s, int sectors,
224 			      int is_new);
225 extern int rdev_clear_badblocks(struct md_rdev *rdev, sector_t s, int sectors,
226 				int is_new);
227 struct md_cluster_info;
228 
229 /* change UNSUPPORTED_MDDEV_FLAGS for each array type if new flag is added */
230 enum mddev_flags {
231 	MD_ARRAY_FIRST_USE,	/* First use of array, needs initialization */
232 	MD_CLOSING,		/* If set, we are closing the array, do not open
233 				 * it then */
234 	MD_JOURNAL_CLEAN,	/* A raid with journal is already clean */
235 	MD_HAS_JOURNAL,		/* The raid array has journal feature set */
236 	MD_CLUSTER_RESYNC_LOCKED, /* cluster raid only, which means node
237 				   * already took resync lock, need to
238 				   * release the lock */
239 	MD_FAILFAST_SUPPORTED,	/* Using MD_FAILFAST on metadata writes is
240 				 * supported as calls to md_error() will
241 				 * never cause the array to become failed.
242 				 */
243 	MD_HAS_PPL,		/* The raid array has PPL feature set */
244 	MD_HAS_MULTIPLE_PPLS,	/* The raid array has multiple PPLs feature set */
245 	MD_ALLOW_SB_UPDATE,	/* md_check_recovery is allowed to update
246 				 * the metadata without taking reconfig_mutex.
247 				 */
248 	MD_UPDATING_SB,		/* md_check_recovery is updating the metadata
249 				 * without explicitly holding reconfig_mutex.
250 				 */
251 	MD_NOT_READY,		/* do_md_run() is active, so 'array_state'
252 				 * must not report that array is ready yet
253 				 */
254 	MD_BROKEN,              /* This is used in RAID-0/LINEAR only, to stop
255 				 * I/O in case an array member is gone/failed.
256 				 */
257 };
258 
259 enum mddev_sb_flags {
260 	MD_SB_CHANGE_DEVS,		/* Some device status has changed */
261 	MD_SB_CHANGE_CLEAN,	/* transition to or from 'clean' */
262 	MD_SB_CHANGE_PENDING,	/* switch from 'clean' to 'active' in progress */
263 	MD_SB_NEED_REWRITE,	/* metadata write needs to be repeated */
264 };
265 
266 #define NR_WB_INFOS	8
267 /* record current range of write behind IOs */
268 struct wb_info {
269 	sector_t lo;
270 	sector_t hi;
271 	struct list_head list;
272 };
273 
274 struct mddev {
275 	void				*private;
276 	struct md_personality		*pers;
277 	dev_t				unit;
278 	int				md_minor;
279 	struct list_head		disks;
280 	unsigned long			flags;
281 	unsigned long			sb_flags;
282 
283 	int				suspended;
284 	atomic_t			active_io;
285 	int				ro;
286 	int				sysfs_active; /* set when sysfs deletes
287 						       * are happening, so run/
288 						       * takeover/stop are not safe
289 						       */
290 	struct gendisk			*gendisk;
291 
292 	struct kobject			kobj;
293 	int				hold_active;
294 #define	UNTIL_IOCTL	1
295 #define	UNTIL_STOP	2
296 
297 	/* Superblock information */
298 	int				major_version,
299 					minor_version,
300 					patch_version;
301 	int				persistent;
302 	int				external;	/* metadata is
303 							 * managed externally */
304 	char				metadata_type[17]; /* externally set*/
305 	int				chunk_sectors;
306 	time64_t			ctime, utime;
307 	int				level, layout;
308 	char				clevel[16];
309 	int				raid_disks;
310 	int				max_disks;
311 	sector_t			dev_sectors;	/* used size of
312 							 * component devices */
313 	sector_t			array_sectors; /* exported array size */
314 	int				external_size; /* size managed
315 							* externally */
316 	__u64				events;
317 	/* If the last 'event' was simply a clean->dirty transition, and
318 	 * we didn't write it to the spares, then it is safe and simple
319 	 * to just decrement the event count on a dirty->clean transition.
320 	 * So we record that possibility here.
321 	 */
322 	int				can_decrease_events;
323 
324 	char				uuid[16];
325 
326 	/* If the array is being reshaped, we need to record the
327 	 * new shape and an indication of where we are up to.
328 	 * This is written to the superblock.
329 	 * If reshape_position is MaxSector, then no reshape is happening (yet).
330 	 */
331 	sector_t			reshape_position;
332 	int				delta_disks, new_level, new_layout;
333 	int				new_chunk_sectors;
334 	int				reshape_backwards;
335 
336 	struct md_thread		*thread;	/* management thread */
337 	struct md_thread		*sync_thread;	/* doing resync or reconstruct */
338 
339 	/* 'last_sync_action' is initialized to "none".  It is set when a
340 	 * sync operation (i.e "data-check", "requested-resync", "resync",
341 	 * "recovery", or "reshape") is started.  It holds this value even
342 	 * when the sync thread is "frozen" (interrupted) or "idle" (stopped
343 	 * or finished).  It is overwritten when a new sync operation is begun.
344 	 */
345 	char				*last_sync_action;
346 	sector_t			curr_resync;	/* last block scheduled */
347 	/* As resync requests can complete out of order, we cannot easily track
348 	 * how much resync has been completed.  So we occasionally pause until
349 	 * everything completes, then set curr_resync_completed to curr_resync.
350 	 * As such it may be well behind the real resync mark, but it is a value
351 	 * we are certain of.
352 	 */
353 	sector_t			curr_resync_completed;
354 	unsigned long			resync_mark;	/* a recent timestamp */
355 	sector_t			resync_mark_cnt;/* blocks written at resync_mark */
356 	sector_t			curr_mark_cnt; /* blocks scheduled now */
357 
358 	sector_t			resync_max_sectors; /* may be set by personality */
359 
360 	atomic64_t			resync_mismatches; /* count of sectors where
361 							    * parity/replica mismatch found
362 							    */
363 
364 	/* allow user-space to request suspension of IO to regions of the array */
365 	sector_t			suspend_lo;
366 	sector_t			suspend_hi;
367 	/* if zero, use the system-wide default */
368 	int				sync_speed_min;
369 	int				sync_speed_max;
370 
371 	/* resync even though the same disks are shared among md-devices */
372 	int				parallel_resync;
373 
374 	int				ok_start_degraded;
375 
376 	unsigned long			recovery;
377 	/* If a RAID personality determines that recovery (of a particular
378 	 * device) will fail due to a read error on the source device, it
379 	 * takes a copy of this number and does not attempt recovery again
380 	 * until this number changes.
381 	 */
382 	int				recovery_disabled;
383 
384 	int				in_sync;	/* know to not need resync */
385 	/* 'open_mutex' avoids races between 'md_open' and 'do_md_stop', so
386 	 * that we are never stopping an array while it is open.
387 	 * 'reconfig_mutex' protects all other reconfiguration.
388 	 * These locks are separate due to conflicting interactions
389 	 * with bdev->bd_mutex.
390 	 * Lock ordering is:
391 	 *  reconfig_mutex -> bd_mutex : e.g. do_md_run -> revalidate_disk
392 	 *  bd_mutex -> open_mutex:  e.g. __blkdev_get -> md_open
393 	 */
394 	struct mutex			open_mutex;
395 	struct mutex			reconfig_mutex;
396 	atomic_t			active;		/* general refcount */
397 	atomic_t			openers;	/* number of active opens */
398 
399 	int				changed;	/* True if we might need to
400 							 * reread partition info */
401 	int				degraded;	/* whether md should consider
402 							 * adding a spare
403 							 */
404 
405 	atomic_t			recovery_active; /* blocks scheduled, but not written */
406 	wait_queue_head_t		recovery_wait;
407 	sector_t			recovery_cp;
408 	sector_t			resync_min;	/* user requested sync
409 							 * starts here */
410 	sector_t			resync_max;	/* resync should pause
411 							 * when it gets here */
412 
413 	struct kernfs_node		*sysfs_state;	/* handle for 'array_state'
414 							 * file in sysfs.
415 							 */
416 	struct kernfs_node		*sysfs_action;  /* handle for 'sync_action' */
417 
418 	struct work_struct del_work;	/* used for delayed sysfs removal */
419 
420 	/* "lock" protects:
421 	 *   flush_bio transition from NULL to !NULL
422 	 *   rdev superblocks, events
423 	 *   clearing MD_CHANGE_*
424 	 *   in_sync - and related safemode and MD_CHANGE changes
425 	 *   pers (also protected by reconfig_mutex and pending IO).
426 	 *   clearing ->bitmap
427 	 *   clearing ->bitmap_info.file
428 	 *   changing ->resync_{min,max}
429 	 *   setting MD_RECOVERY_RUNNING (which interacts with resync_{min,max})
430 	 */
431 	spinlock_t			lock;
432 	wait_queue_head_t		sb_wait;	/* for waiting on superblock updates */
433 	atomic_t			pending_writes;	/* number of active superblock writes */
434 
435 	unsigned int			safemode;	/* if set, update "clean" superblock
436 							 * when no writes pending.
437 							 */
438 	unsigned int			safemode_delay;
439 	struct timer_list		safemode_timer;
440 	struct percpu_ref		writes_pending;
441 	int				sync_checkers;	/* # of threads checking writes_pending */
442 	struct request_queue		*queue;	/* for plugging ... */
443 
444 	struct bitmap			*bitmap; /* the bitmap for the device */
445 	struct {
446 		struct file		*file; /* the bitmap file */
447 		loff_t			offset; /* offset from superblock of
448 						 * start of bitmap. May be
449 						 * negative, but not '0'
450 						 * For external metadata, offset
451 						 * from start of device.
452 						 */
453 		unsigned long		space; /* space available at this offset */
454 		loff_t			default_offset; /* this is the offset to use when
455 							 * hot-adding a bitmap.  It should
456 							 * eventually be settable by sysfs.
457 							 */
458 		unsigned long		default_space; /* space available at
459 							* default offset */
460 		struct mutex		mutex;
461 		unsigned long		chunksize;
462 		unsigned long		daemon_sleep; /* how many jiffies between updates? */
463 		unsigned long		max_write_behind; /* write-behind mode */
464 		int			external;
465 		int			nodes; /* Maximum number of nodes in the cluster */
466 		char                    cluster_name[64]; /* Name of the cluster */
467 	} bitmap_info;
468 
469 	atomic_t			max_corr_read_errors; /* max read retries */
470 	struct list_head		all_mddevs;
471 
472 	struct attribute_group		*to_remove;
473 
474 	struct bio_set			bio_set;
475 	struct bio_set			sync_set; /* for sync operations like
476 						   * metadata and bitmap writes
477 						   */
478 
479 	/* Generic flush handling.
480 	 * The last to finish preflush schedules a worker to submit
481 	 * the rest of the request (without the REQ_PREFLUSH flag).
482 	 */
483 	struct bio *flush_bio;
484 	atomic_t flush_pending;
485 	ktime_t start_flush, last_flush; /* last_flush is when the last completed
486 					  * flush was started.
487 					  */
488 	struct work_struct flush_work;
489 	struct work_struct event_work;	/* used by dm to report failure event */
490 	mempool_t *wb_info_pool;
491 	void (*sync_super)(struct mddev *mddev, struct md_rdev *rdev);
492 	struct md_cluster_info		*cluster_info;
493 	unsigned int			good_device_nr;	/* good device num within cluster raid */
494 
495 	bool	has_superblocks:1;
496 	bool	fail_last_dev:1;
497 };
498 
499 enum recovery_flags {
500 	/*
501 	 * If neither SYNC or RESHAPE are set, then it is a recovery.
502 	 */
503 	MD_RECOVERY_RUNNING,	/* a thread is running, or about to be started */
504 	MD_RECOVERY_SYNC,	/* actually doing a resync, not a recovery */
505 	MD_RECOVERY_RECOVER,	/* doing recovery, or need to try it. */
506 	MD_RECOVERY_INTR,	/* resync needs to be aborted for some reason */
507 	MD_RECOVERY_DONE,	/* thread is done and is waiting to be reaped */
508 	MD_RECOVERY_NEEDED,	/* we might need to start a resync/recover */
509 	MD_RECOVERY_REQUESTED,	/* user-space has requested a sync (used with SYNC) */
510 	MD_RECOVERY_CHECK,	/* user-space request for check-only, no repair */
511 	MD_RECOVERY_RESHAPE,	/* A reshape is happening */
512 	MD_RECOVERY_FROZEN,	/* User request to abort, and not restart, any action */
513 	MD_RECOVERY_ERROR,	/* sync-action interrupted because io-error */
514 	MD_RECOVERY_WAIT,	/* waiting for pers->start() to finish */
515 	MD_RESYNCING_REMOTE,	/* remote node is running resync thread */
516 };
517 
518 static inline int __must_check mddev_lock(struct mddev *mddev)
519 {
520 	return mutex_lock_interruptible(&mddev->reconfig_mutex);
521 }
522 
523 /* Sometimes we need to take the lock in a situation where
524  * failure due to interrupts is not acceptable.
525  */
526 static inline void mddev_lock_nointr(struct mddev *mddev)
527 {
528 	mutex_lock(&mddev->reconfig_mutex);
529 }
530 
531 static inline int mddev_trylock(struct mddev *mddev)
532 {
533 	return mutex_trylock(&mddev->reconfig_mutex);
534 }
535 extern void mddev_unlock(struct mddev *mddev);
536 
537 static inline void md_sync_acct(struct block_device *bdev, unsigned long nr_sectors)
538 {
539 	atomic_add(nr_sectors, &bdev->bd_contains->bd_disk->sync_io);
540 }
541 
542 static inline void md_sync_acct_bio(struct bio *bio, unsigned long nr_sectors)
543 {
544 	atomic_add(nr_sectors, &bio->bi_disk->sync_io);
545 }
546 
547 struct md_personality
548 {
549 	char *name;
550 	int level;
551 	struct list_head list;
552 	struct module *owner;
553 	bool __must_check (*make_request)(struct mddev *mddev, struct bio *bio);
554 	/*
555 	 * start up works that do NOT require md_thread. tasks that
556 	 * requires md_thread should go into start()
557 	 */
558 	int (*run)(struct mddev *mddev);
559 	/* start up works that require md threads */
560 	int (*start)(struct mddev *mddev);
561 	void (*free)(struct mddev *mddev, void *priv);
562 	void (*status)(struct seq_file *seq, struct mddev *mddev);
563 	/* error_handler must set ->faulty and clear ->in_sync
564 	 * if appropriate, and should abort recovery if needed
565 	 */
566 	void (*error_handler)(struct mddev *mddev, struct md_rdev *rdev);
567 	int (*hot_add_disk) (struct mddev *mddev, struct md_rdev *rdev);
568 	int (*hot_remove_disk) (struct mddev *mddev, struct md_rdev *rdev);
569 	int (*spare_active) (struct mddev *mddev);
570 	sector_t (*sync_request)(struct mddev *mddev, sector_t sector_nr, int *skipped);
571 	int (*resize) (struct mddev *mddev, sector_t sectors);
572 	sector_t (*size) (struct mddev *mddev, sector_t sectors, int raid_disks);
573 	int (*check_reshape) (struct mddev *mddev);
574 	int (*start_reshape) (struct mddev *mddev);
575 	void (*finish_reshape) (struct mddev *mddev);
576 	void (*update_reshape_pos) (struct mddev *mddev);
577 	/* quiesce suspends or resumes internal processing.
578 	 * 1 - stop new actions and wait for action io to complete
579 	 * 0 - return to normal behaviour
580 	 */
581 	void (*quiesce) (struct mddev *mddev, int quiesce);
582 	/* takeover is used to transition an array from one
583 	 * personality to another.  The new personality must be able
584 	 * to handle the data in the current layout.
585 	 * e.g. 2drive raid1 -> 2drive raid5
586 	 *      ndrive raid5 -> degraded n+1drive raid6 with special layout
587 	 * If the takeover succeeds, a new 'private' structure is returned.
588 	 * This needs to be installed and then ->run used to activate the
589 	 * array.
590 	 */
591 	void *(*takeover) (struct mddev *mddev);
592 	/* congested implements bdi.congested_fn().
593 	 * Will not be called while array is 'suspended' */
594 	int (*congested)(struct mddev *mddev, int bits);
595 	/* Changes the consistency policy of an active array. */
596 	int (*change_consistency_policy)(struct mddev *mddev, const char *buf);
597 };
598 
599 struct md_sysfs_entry {
600 	struct attribute attr;
601 	ssize_t (*show)(struct mddev *, char *);
602 	ssize_t (*store)(struct mddev *, const char *, size_t);
603 };
604 extern struct attribute_group md_bitmap_group;
605 
606 static inline struct kernfs_node *sysfs_get_dirent_safe(struct kernfs_node *sd, char *name)
607 {
608 	if (sd)
609 		return sysfs_get_dirent(sd, name);
610 	return sd;
611 }
612 static inline void sysfs_notify_dirent_safe(struct kernfs_node *sd)
613 {
614 	if (sd)
615 		sysfs_notify_dirent(sd);
616 }
617 
618 static inline char * mdname (struct mddev * mddev)
619 {
620 	return mddev->gendisk ? mddev->gendisk->disk_name : "mdX";
621 }
622 
623 static inline int sysfs_link_rdev(struct mddev *mddev, struct md_rdev *rdev)
624 {
625 	char nm[20];
626 	if (!test_bit(Replacement, &rdev->flags) &&
627 	    !test_bit(Journal, &rdev->flags) &&
628 	    mddev->kobj.sd) {
629 		sprintf(nm, "rd%d", rdev->raid_disk);
630 		return sysfs_create_link(&mddev->kobj, &rdev->kobj, nm);
631 	} else
632 		return 0;
633 }
634 
635 static inline void sysfs_unlink_rdev(struct mddev *mddev, struct md_rdev *rdev)
636 {
637 	char nm[20];
638 	if (!test_bit(Replacement, &rdev->flags) &&
639 	    !test_bit(Journal, &rdev->flags) &&
640 	    mddev->kobj.sd) {
641 		sprintf(nm, "rd%d", rdev->raid_disk);
642 		sysfs_remove_link(&mddev->kobj, nm);
643 	}
644 }
645 
646 /*
647  * iterates through some rdev ringlist. It's safe to remove the
648  * current 'rdev'. Dont touch 'tmp' though.
649  */
650 #define rdev_for_each_list(rdev, tmp, head)				\
651 	list_for_each_entry_safe(rdev, tmp, head, same_set)
652 
653 /*
654  * iterates through the 'same array disks' ringlist
655  */
656 #define rdev_for_each(rdev, mddev)				\
657 	list_for_each_entry(rdev, &((mddev)->disks), same_set)
658 
659 #define rdev_for_each_safe(rdev, tmp, mddev)				\
660 	list_for_each_entry_safe(rdev, tmp, &((mddev)->disks), same_set)
661 
662 #define rdev_for_each_rcu(rdev, mddev)				\
663 	list_for_each_entry_rcu(rdev, &((mddev)->disks), same_set)
664 
665 struct md_thread {
666 	void			(*run) (struct md_thread *thread);
667 	struct mddev		*mddev;
668 	wait_queue_head_t	wqueue;
669 	unsigned long		flags;
670 	struct task_struct	*tsk;
671 	unsigned long		timeout;
672 	void			*private;
673 };
674 
675 #define THREAD_WAKEUP  0
676 
677 static inline void safe_put_page(struct page *p)
678 {
679 	if (p) put_page(p);
680 }
681 
682 extern int register_md_personality(struct md_personality *p);
683 extern int unregister_md_personality(struct md_personality *p);
684 extern int register_md_cluster_operations(struct md_cluster_operations *ops,
685 		struct module *module);
686 extern int unregister_md_cluster_operations(void);
687 extern int md_setup_cluster(struct mddev *mddev, int nodes);
688 extern void md_cluster_stop(struct mddev *mddev);
689 extern struct md_thread *md_register_thread(
690 	void (*run)(struct md_thread *thread),
691 	struct mddev *mddev,
692 	const char *name);
693 extern void md_unregister_thread(struct md_thread **threadp);
694 extern void md_wakeup_thread(struct md_thread *thread);
695 extern void md_check_recovery(struct mddev *mddev);
696 extern void md_reap_sync_thread(struct mddev *mddev);
697 extern int mddev_init_writes_pending(struct mddev *mddev);
698 extern bool md_write_start(struct mddev *mddev, struct bio *bi);
699 extern void md_write_inc(struct mddev *mddev, struct bio *bi);
700 extern void md_write_end(struct mddev *mddev);
701 extern void md_done_sync(struct mddev *mddev, int blocks, int ok);
702 extern void md_error(struct mddev *mddev, struct md_rdev *rdev);
703 extern void md_finish_reshape(struct mddev *mddev);
704 
705 extern int mddev_congested(struct mddev *mddev, int bits);
706 extern bool __must_check md_flush_request(struct mddev *mddev, struct bio *bio);
707 extern void md_super_write(struct mddev *mddev, struct md_rdev *rdev,
708 			   sector_t sector, int size, struct page *page);
709 extern int md_super_wait(struct mddev *mddev);
710 extern int sync_page_io(struct md_rdev *rdev, sector_t sector, int size,
711 			struct page *page, int op, int op_flags,
712 			bool metadata_op);
713 extern void md_do_sync(struct md_thread *thread);
714 extern void md_new_event(struct mddev *mddev);
715 extern void md_allow_write(struct mddev *mddev);
716 extern void md_wait_for_blocked_rdev(struct md_rdev *rdev, struct mddev *mddev);
717 extern void md_set_array_sectors(struct mddev *mddev, sector_t array_sectors);
718 extern int md_check_no_bitmap(struct mddev *mddev);
719 extern int md_integrity_register(struct mddev *mddev);
720 extern int md_integrity_add_rdev(struct md_rdev *rdev, struct mddev *mddev);
721 extern int strict_strtoul_scaled(const char *cp, unsigned long *res, int scale);
722 
723 extern void mddev_init(struct mddev *mddev);
724 extern int md_run(struct mddev *mddev);
725 extern int md_start(struct mddev *mddev);
726 extern void md_stop(struct mddev *mddev);
727 extern void md_stop_writes(struct mddev *mddev);
728 extern int md_rdev_init(struct md_rdev *rdev);
729 extern void md_rdev_clear(struct md_rdev *rdev);
730 
731 extern void md_handle_request(struct mddev *mddev, struct bio *bio);
732 extern void mddev_suspend(struct mddev *mddev);
733 extern void mddev_resume(struct mddev *mddev);
734 extern struct bio *bio_alloc_mddev(gfp_t gfp_mask, int nr_iovecs,
735 				   struct mddev *mddev);
736 
737 extern void md_reload_sb(struct mddev *mddev, int raid_disk);
738 extern void md_update_sb(struct mddev *mddev, int force);
739 extern void md_kick_rdev_from_array(struct md_rdev * rdev);
740 extern void mddev_create_wb_pool(struct mddev *mddev, struct md_rdev *rdev,
741 				 bool is_suspend);
742 struct md_rdev *md_find_rdev_nr_rcu(struct mddev *mddev, int nr);
743 struct md_rdev *md_find_rdev_rcu(struct mddev *mddev, dev_t dev);
744 
745 static inline bool is_mddev_broken(struct md_rdev *rdev, const char *md_type)
746 {
747 	int flags = rdev->bdev->bd_disk->flags;
748 
749 	if (!(flags & GENHD_FL_UP)) {
750 		if (!test_and_set_bit(MD_BROKEN, &rdev->mddev->flags))
751 			pr_warn("md: %s: %s array has a missing/failed member\n",
752 				mdname(rdev->mddev), md_type);
753 		return true;
754 	}
755 	return false;
756 }
757 
758 static inline void rdev_dec_pending(struct md_rdev *rdev, struct mddev *mddev)
759 {
760 	int faulty = test_bit(Faulty, &rdev->flags);
761 	if (atomic_dec_and_test(&rdev->nr_pending) && faulty) {
762 		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
763 		md_wakeup_thread(mddev->thread);
764 	}
765 }
766 
767 extern struct md_cluster_operations *md_cluster_ops;
768 static inline int mddev_is_clustered(struct mddev *mddev)
769 {
770 	return mddev->cluster_info && mddev->bitmap_info.nodes > 1;
771 }
772 
773 /* clear unsupported mddev_flags */
774 static inline void mddev_clear_unsupported_flags(struct mddev *mddev,
775 	unsigned long unsupported_flags)
776 {
777 	mddev->flags &= ~unsupported_flags;
778 }
779 
780 static inline void mddev_check_writesame(struct mddev *mddev, struct bio *bio)
781 {
782 	if (bio_op(bio) == REQ_OP_WRITE_SAME &&
783 	    !bio->bi_disk->queue->limits.max_write_same_sectors)
784 		mddev->queue->limits.max_write_same_sectors = 0;
785 }
786 
787 static inline void mddev_check_write_zeroes(struct mddev *mddev, struct bio *bio)
788 {
789 	if (bio_op(bio) == REQ_OP_WRITE_ZEROES &&
790 	    !bio->bi_disk->queue->limits.max_write_zeroes_sectors)
791 		mddev->queue->limits.max_write_zeroes_sectors = 0;
792 }
793 #endif /* _MD_MD_H */
794