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