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);
is_badblock(struct md_rdev * rdev,sector_t s,int sectors,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 atomic64_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 * ERROR: sync-action interrupted because io-error
311 *
312 * If neither SYNC or RESHAPE are set, then it is a recovery.
313 */
314 #define MD_RECOVERY_RUNNING 0
315 #define MD_RECOVERY_SYNC 1
316 #define MD_RECOVERY_RECOVER 2
317 #define MD_RECOVERY_INTR 3
318 #define MD_RECOVERY_DONE 4
319 #define MD_RECOVERY_NEEDED 5
320 #define MD_RECOVERY_REQUESTED 6
321 #define MD_RECOVERY_CHECK 7
322 #define MD_RECOVERY_RESHAPE 8
323 #define MD_RECOVERY_FROZEN 9
324 #define MD_RECOVERY_ERROR 10
325
326 unsigned long recovery;
327 /* If a RAID personality determines that recovery (of a particular
328 * device) will fail due to a read error on the source device, it
329 * takes a copy of this number and does not attempt recovery again
330 * until this number changes.
331 */
332 int recovery_disabled;
333
334 int in_sync; /* know to not need resync */
335 /* 'open_mutex' avoids races between 'md_open' and 'do_md_stop', so
336 * that we are never stopping an array while it is open.
337 * 'reconfig_mutex' protects all other reconfiguration.
338 * These locks are separate due to conflicting interactions
339 * with bdev->bd_mutex.
340 * Lock ordering is:
341 * reconfig_mutex -> bd_mutex : e.g. do_md_run -> revalidate_disk
342 * bd_mutex -> open_mutex: e.g. __blkdev_get -> md_open
343 */
344 struct mutex open_mutex;
345 struct mutex reconfig_mutex;
346 atomic_t active; /* general refcount */
347 atomic_t openers; /* number of active opens */
348
349 int changed; /* True if we might need to
350 * reread partition info */
351 int degraded; /* whether md should consider
352 * adding a spare
353 */
354 int merge_check_needed; /* at least one
355 * member device
356 * has a
357 * merge_bvec_fn */
358
359 atomic_t recovery_active; /* blocks scheduled, but not written */
360 wait_queue_head_t recovery_wait;
361 sector_t recovery_cp;
362 sector_t resync_min; /* user requested sync
363 * starts here */
364 sector_t resync_max; /* resync should pause
365 * when it gets here */
366
367 struct sysfs_dirent *sysfs_state; /* handle for 'array_state'
368 * file in sysfs.
369 */
370 struct sysfs_dirent *sysfs_action; /* handle for 'sync_action' */
371
372 struct work_struct del_work; /* used for delayed sysfs removal */
373
374 spinlock_t write_lock;
375 wait_queue_head_t sb_wait; /* for waiting on superblock updates */
376 atomic_t pending_writes; /* number of active superblock writes */
377
378 unsigned int safemode; /* if set, update "clean" superblock
379 * when no writes pending.
380 */
381 unsigned int safemode_delay;
382 struct timer_list safemode_timer;
383 atomic_t writes_pending;
384 struct request_queue *queue; /* for plugging ... */
385
386 struct bitmap *bitmap; /* the bitmap for the device */
387 struct {
388 struct file *file; /* the bitmap file */
389 loff_t offset; /* offset from superblock of
390 * start of bitmap. May be
391 * negative, but not '0'
392 * For external metadata, offset
393 * from start of device.
394 */
395 unsigned long space; /* space available at this offset */
396 loff_t default_offset; /* this is the offset to use when
397 * hot-adding a bitmap. It should
398 * eventually be settable by sysfs.
399 */
400 unsigned long default_space; /* space available at
401 * default offset */
402 struct mutex mutex;
403 unsigned long chunksize;
404 unsigned long daemon_sleep; /* how many jiffies between updates? */
405 unsigned long max_write_behind; /* write-behind mode */
406 int external;
407 } bitmap_info;
408
409 atomic_t max_corr_read_errors; /* max read retries */
410 struct list_head all_mddevs;
411
412 struct attribute_group *to_remove;
413
414 struct bio_set *bio_set;
415
416 /* Generic flush handling.
417 * The last to finish preflush schedules a worker to submit
418 * the rest of the request (without the REQ_FLUSH flag).
419 */
420 struct bio *flush_bio;
421 atomic_t flush_pending;
422 struct work_struct flush_work;
423 struct work_struct event_work; /* used by dm to report failure event */
424 void (*sync_super)(struct mddev *mddev, struct md_rdev *rdev);
425 };
426
427
rdev_dec_pending(struct md_rdev * rdev,struct mddev * mddev)428 static inline void rdev_dec_pending(struct md_rdev *rdev, struct mddev *mddev)
429 {
430 int faulty = test_bit(Faulty, &rdev->flags);
431 if (atomic_dec_and_test(&rdev->nr_pending) && faulty)
432 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
433 }
434
md_sync_acct(struct block_device * bdev,unsigned long nr_sectors)435 static inline void md_sync_acct(struct block_device *bdev, unsigned long nr_sectors)
436 {
437 atomic_add(nr_sectors, &bdev->bd_contains->bd_disk->sync_io);
438 }
439
440 struct md_personality
441 {
442 char *name;
443 int level;
444 struct list_head list;
445 struct module *owner;
446 void (*make_request)(struct mddev *mddev, struct bio *bio);
447 int (*run)(struct mddev *mddev);
448 int (*stop)(struct mddev *mddev);
449 void (*status)(struct seq_file *seq, struct mddev *mddev);
450 /* error_handler must set ->faulty and clear ->in_sync
451 * if appropriate, and should abort recovery if needed
452 */
453 void (*error_handler)(struct mddev *mddev, struct md_rdev *rdev);
454 int (*hot_add_disk) (struct mddev *mddev, struct md_rdev *rdev);
455 int (*hot_remove_disk) (struct mddev *mddev, struct md_rdev *rdev);
456 int (*spare_active) (struct mddev *mddev);
457 sector_t (*sync_request)(struct mddev *mddev, sector_t sector_nr, int *skipped, int go_faster);
458 int (*resize) (struct mddev *mddev, sector_t sectors);
459 sector_t (*size) (struct mddev *mddev, sector_t sectors, int raid_disks);
460 int (*check_reshape) (struct mddev *mddev);
461 int (*start_reshape) (struct mddev *mddev);
462 void (*finish_reshape) (struct mddev *mddev);
463 /* quiesce moves between quiescence states
464 * 0 - fully active
465 * 1 - no new requests allowed
466 * others - reserved
467 */
468 void (*quiesce) (struct mddev *mddev, int state);
469 /* takeover is used to transition an array from one
470 * personality to another. The new personality must be able
471 * to handle the data in the current layout.
472 * e.g. 2drive raid1 -> 2drive raid5
473 * ndrive raid5 -> degraded n+1drive raid6 with special layout
474 * If the takeover succeeds, a new 'private' structure is returned.
475 * This needs to be installed and then ->run used to activate the
476 * array.
477 */
478 void *(*takeover) (struct mddev *mddev);
479 };
480
481
482 struct md_sysfs_entry {
483 struct attribute attr;
484 ssize_t (*show)(struct mddev *, char *);
485 ssize_t (*store)(struct mddev *, const char *, size_t);
486 };
487 extern struct attribute_group md_bitmap_group;
488
sysfs_get_dirent_safe(struct sysfs_dirent * sd,char * name)489 static inline struct sysfs_dirent *sysfs_get_dirent_safe(struct sysfs_dirent *sd, char *name)
490 {
491 if (sd)
492 return sysfs_get_dirent(sd, NULL, name);
493 return sd;
494 }
sysfs_notify_dirent_safe(struct sysfs_dirent * sd)495 static inline void sysfs_notify_dirent_safe(struct sysfs_dirent *sd)
496 {
497 if (sd)
498 sysfs_notify_dirent(sd);
499 }
500
mdname(struct mddev * mddev)501 static inline char * mdname (struct mddev * mddev)
502 {
503 return mddev->gendisk ? mddev->gendisk->disk_name : "mdX";
504 }
505
sysfs_link_rdev(struct mddev * mddev,struct md_rdev * rdev)506 static inline int sysfs_link_rdev(struct mddev *mddev, struct md_rdev *rdev)
507 {
508 char nm[20];
509 if (!test_bit(Replacement, &rdev->flags) && mddev->kobj.sd) {
510 sprintf(nm, "rd%d", rdev->raid_disk);
511 return sysfs_create_link(&mddev->kobj, &rdev->kobj, nm);
512 } else
513 return 0;
514 }
515
sysfs_unlink_rdev(struct mddev * mddev,struct md_rdev * rdev)516 static inline void sysfs_unlink_rdev(struct mddev *mddev, struct md_rdev *rdev)
517 {
518 char nm[20];
519 if (!test_bit(Replacement, &rdev->flags) && mddev->kobj.sd) {
520 sprintf(nm, "rd%d", rdev->raid_disk);
521 sysfs_remove_link(&mddev->kobj, nm);
522 }
523 }
524
525 /*
526 * iterates through some rdev ringlist. It's safe to remove the
527 * current 'rdev'. Dont touch 'tmp' though.
528 */
529 #define rdev_for_each_list(rdev, tmp, head) \
530 list_for_each_entry_safe(rdev, tmp, head, same_set)
531
532 /*
533 * iterates through the 'same array disks' ringlist
534 */
535 #define rdev_for_each(rdev, mddev) \
536 list_for_each_entry(rdev, &((mddev)->disks), same_set)
537
538 #define rdev_for_each_safe(rdev, tmp, mddev) \
539 list_for_each_entry_safe(rdev, tmp, &((mddev)->disks), same_set)
540
541 #define rdev_for_each_rcu(rdev, mddev) \
542 list_for_each_entry_rcu(rdev, &((mddev)->disks), same_set)
543
544 struct md_thread {
545 void (*run) (struct md_thread *thread);
546 struct mddev *mddev;
547 wait_queue_head_t wqueue;
548 unsigned long flags;
549 struct task_struct *tsk;
550 unsigned long timeout;
551 void *private;
552 };
553
554 #define THREAD_WAKEUP 0
555
safe_put_page(struct page * p)556 static inline void safe_put_page(struct page *p)
557 {
558 if (p) put_page(p);
559 }
560
561 extern int register_md_personality(struct md_personality *p);
562 extern int unregister_md_personality(struct md_personality *p);
563 extern struct md_thread *md_register_thread(
564 void (*run)(struct md_thread *thread),
565 struct mddev *mddev,
566 const char *name);
567 extern void md_unregister_thread(struct md_thread **threadp);
568 extern void md_wakeup_thread(struct md_thread *thread);
569 extern void md_check_recovery(struct mddev *mddev);
570 extern void md_reap_sync_thread(struct mddev *mddev);
571 extern void md_write_start(struct mddev *mddev, struct bio *bi);
572 extern void md_write_end(struct mddev *mddev);
573 extern void md_done_sync(struct mddev *mddev, int blocks, int ok);
574 extern void md_error(struct mddev *mddev, struct md_rdev *rdev);
575 extern void md_finish_reshape(struct mddev *mddev);
576
577 extern int mddev_congested(struct mddev *mddev, int bits);
578 extern void md_flush_request(struct mddev *mddev, struct bio *bio);
579 extern void md_super_write(struct mddev *mddev, struct md_rdev *rdev,
580 sector_t sector, int size, struct page *page);
581 extern void md_super_wait(struct mddev *mddev);
582 extern int sync_page_io(struct md_rdev *rdev, sector_t sector, int size,
583 struct page *page, int rw, bool metadata_op);
584 extern void md_do_sync(struct md_thread *thread);
585 extern void md_new_event(struct mddev *mddev);
586 extern int md_allow_write(struct mddev *mddev);
587 extern void md_wait_for_blocked_rdev(struct md_rdev *rdev, struct mddev *mddev);
588 extern void md_set_array_sectors(struct mddev *mddev, sector_t array_sectors);
589 extern int md_check_no_bitmap(struct mddev *mddev);
590 extern int md_integrity_register(struct mddev *mddev);
591 extern void md_integrity_add_rdev(struct md_rdev *rdev, struct mddev *mddev);
592 extern int strict_strtoul_scaled(const char *cp, unsigned long *res, int scale);
593 extern void restore_bitmap_write_access(struct file *file);
594
595 extern void mddev_init(struct mddev *mddev);
596 extern int md_run(struct mddev *mddev);
597 extern void md_stop(struct mddev *mddev);
598 extern void md_stop_writes(struct mddev *mddev);
599 extern int md_rdev_init(struct md_rdev *rdev);
600 extern void md_rdev_clear(struct md_rdev *rdev);
601
602 extern void mddev_suspend(struct mddev *mddev);
603 extern void mddev_resume(struct mddev *mddev);
604 extern struct bio *bio_clone_mddev(struct bio *bio, gfp_t gfp_mask,
605 struct mddev *mddev);
606 extern struct bio *bio_alloc_mddev(gfp_t gfp_mask, int nr_iovecs,
607 struct mddev *mddev);
608 extern void md_trim_bio(struct bio *bio, int offset, int size);
609
610 extern void md_unplug(struct blk_plug_cb *cb, bool from_schedule);
mddev_check_plugged(struct mddev * mddev)611 static inline int mddev_check_plugged(struct mddev *mddev)
612 {
613 return !!blk_check_plugged(md_unplug, mddev,
614 sizeof(struct blk_plug_cb));
615 }
616 #endif /* _MD_MD_H */
617