2 md_k.h : kernel internal structure of the Linux MD driver
3 Copyright (C) 1996-98 Ingo Molnar, Gadi Oxman
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)
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.
18 #include <linux/blkdev.h>
19 #include <linux/kobject.h>
20 #include <linux/list.h>
22 #include <linux/mutex.h>
23 #include <linux/timer.h>
24 #include <linux/wait.h>
25 #include <linux/workqueue.h>
27 #define MaxSector (~(sector_t)0)
29 typedef struct mddev_s mddev_t;
30 typedef struct mdk_rdev_s mdk_rdev_t;
32 /* Bad block numbers are stored sorted in a single page.
33 * 64bits is used for each block or extent.
34 * 54 bits are sector number, 9 bits are extent size,
35 * 1 bit is an 'acknowledged' flag.
37 #define MD_MAX_BADBLOCKS (PAGE_SIZE/8)
40 * MD's 'extended' device
44 struct list_head same_set; /* RAID devices within the same set */
46 sector_t sectors; /* Device size (in 512bytes sectors) */
47 mddev_t *mddev; /* RAID array if running */
48 int last_events; /* IO event timestamp */
51 * If meta_bdev is non-NULL, it means that a separate device is
52 * being used to store the metadata (superblock/bitmap) which
53 * would otherwise be contained on the same device as the data (bdev).
55 struct block_device *meta_bdev;
56 struct block_device *bdev; /* block device handle */
58 struct page *sb_page, *bb_page;
61 sector_t data_offset; /* start of data in array */
62 sector_t sb_start; /* offset of the super block (in 512byte sectors) */
63 int sb_size; /* bytes in the superblock */
64 int preferred_minor; /* autorun support */
68 /* A device can be in one of three states based on two flags:
69 * Not working: faulty==1 in_sync==0
70 * Fully working: faulty==0 in_sync==1
73 * faulty==0 in_sync==0
75 * It can never have faulty==1, in_sync==1
76 * This reduces the burden of testing multiple flags in many cases
80 #define Faulty 1 /* device is known to have a fault */
81 #define In_sync 2 /* device is in_sync with rest of array */
82 #define WriteMostly 4 /* Avoid reading if at all possible */
83 #define AutoDetected 7 /* added by auto-detect */
84 #define Blocked 8 /* An error occurred on an externally
85 * managed array, don't allow writes
86 * until it is cleared */
87 wait_queue_head_t blocked_wait;
89 int desc_nr; /* descriptor index in the superblock */
90 int raid_disk; /* role of device in array */
91 int new_raid_disk; /* role that the device will have in
92 * the array after a level-change completes.
94 int saved_raid_disk; /* role that device used to have in the
95 * array and could again if we did a partial
96 * resync from the bitmap
98 sector_t recovery_offset;/* If this device has been partially
99 * recovered, this is where we were
103 atomic_t nr_pending; /* number of pending requests.
104 * only maintained for arrays that
105 * support hot removal
107 atomic_t read_errors; /* number of consecutive read errors that
108 * we have tried to ignore.
110 struct timespec last_read_error; /* monotonic time since our
113 atomic_t corrected_errors; /* number of corrected read errors,
114 * for reporting to userspace and storing
117 struct work_struct del_work; /* used for delayed sysfs removal */
119 struct sysfs_dirent *sysfs_state; /* handle for 'state'
123 int count; /* count of bad blocks */
124 int shift; /* shift from sectors to block size
125 * a -ve shift means badblocks are
127 u64 *page; /* badblock list */
132 sector_t size; /* in sectors */
136 #define BB_LEN_MASK (0x00000000000001FFULL)
137 #define BB_OFFSET_MASK (0x7FFFFFFFFFFFFE00ULL)
138 #define BB_ACK_MASK (0x8000000000000000ULL)
139 #define BB_MAX_LEN 512
140 #define BB_OFFSET(x) (((x) & BB_OFFSET_MASK) >> 9)
141 #define BB_LEN(x) (((x) & BB_LEN_MASK) + 1)
142 #define BB_ACK(x) (!!((x) & BB_ACK_MASK))
143 #define BB_MAKE(a, l, ack) (((a)<<9) | ((l)-1) | ((u64)(!!(ack)) << 63))
145 extern int md_is_badblock(struct badblocks *bb, sector_t s, int sectors,
146 sector_t *first_bad, int *bad_sectors);
147 static inline int is_badblock(mdk_rdev_t *rdev, sector_t s, int sectors,
148 sector_t *first_bad, int *bad_sectors)
150 if (unlikely(rdev->badblocks.count)) {
151 int rv = md_is_badblock(&rdev->badblocks, rdev->data_offset + s,
153 first_bad, bad_sectors);
155 *first_bad -= rdev->data_offset;
160 extern int rdev_set_badblocks(mdk_rdev_t *rdev, sector_t s, int sectors,
162 extern int rdev_clear_badblocks(mdk_rdev_t *rdev, sector_t s, int sectors);
163 extern void md_ack_all_badblocks(struct badblocks *bb);
168 struct mdk_personality *pers;
171 struct list_head disks;
173 #define MD_CHANGE_DEVS 0 /* Some device status has changed */
174 #define MD_CHANGE_CLEAN 1 /* transition to or from 'clean' */
175 #define MD_CHANGE_PENDING 2 /* switch from 'clean' to 'active' in progress */
176 #define MD_ARRAY_FIRST_USE 3 /* First use of array, needs initialization */
181 int sysfs_active; /* set when sysfs deletes
182 * are happening, so run/
183 * takeover/stop are not safe
185 int ready; /* See when safe to pass
186 * IO requests down */
187 struct gendisk *gendisk;
191 #define UNTIL_IOCTL 1
194 /* Superblock information */
199 int external; /* metadata is
200 * managed externally */
201 char metadata_type[17]; /* externally set*/
208 sector_t dev_sectors; /* used size of
209 * component devices */
210 sector_t array_sectors; /* exported array size */
211 int external_size; /* size managed
214 /* If the last 'event' was simply a clean->dirty transition, and
215 * we didn't write it to the spares, then it is safe and simple
216 * to just decrement the event count on a dirty->clean transition.
217 * So we record that possibility here.
219 int can_decrease_events;
223 /* If the array is being reshaped, we need to record the
224 * new shape and an indication of where we are up to.
225 * This is written to the superblock.
226 * If reshape_position is MaxSector, then no reshape is happening (yet).
228 sector_t reshape_position;
229 int delta_disks, new_level, new_layout;
230 int new_chunk_sectors;
232 atomic_t plug_cnt; /* If device is expecting
235 struct mdk_thread_s *thread; /* management thread */
236 struct mdk_thread_s *sync_thread; /* doing resync or reconstruct */
237 sector_t curr_resync; /* last block scheduled */
238 /* As resync requests can complete out of order, we cannot easily track
239 * how much resync has been completed. So we occasionally pause until
240 * everything completes, then set curr_resync_completed to curr_resync.
241 * As such it may be well behind the real resync mark, but it is a value
244 sector_t curr_resync_completed;
245 unsigned long resync_mark; /* a recent timestamp */
246 sector_t resync_mark_cnt;/* blocks written at resync_mark */
247 sector_t curr_mark_cnt; /* blocks scheduled now */
249 sector_t resync_max_sectors; /* may be set by personality */
251 sector_t resync_mismatches; /* count of sectors where
252 * parity/replica mismatch found
255 /* allow user-space to request suspension of IO to regions of the array */
258 /* if zero, use the system-wide default */
262 /* resync even though the same disks are shared among md-devices */
265 int ok_start_degraded;
266 /* recovery/resync flags
267 * NEEDED: we might need to start a resync/recover
268 * RUNNING: a thread is running, or about to be started
269 * SYNC: actually doing a resync, not a recovery
270 * RECOVER: doing recovery, or need to try it.
271 * INTR: resync needs to be aborted for some reason
272 * DONE: thread is done and is waiting to be reaped
273 * REQUEST: user-space has requested a sync (used with SYNC)
274 * CHECK: user-space request for check-only, no repair
275 * RESHAPE: A reshape is happening
277 * If neither SYNC or RESHAPE are set, then it is a recovery.
279 #define MD_RECOVERY_RUNNING 0
280 #define MD_RECOVERY_SYNC 1
281 #define MD_RECOVERY_RECOVER 2
282 #define MD_RECOVERY_INTR 3
283 #define MD_RECOVERY_DONE 4
284 #define MD_RECOVERY_NEEDED 5
285 #define MD_RECOVERY_REQUESTED 6
286 #define MD_RECOVERY_CHECK 7
287 #define MD_RECOVERY_RESHAPE 8
288 #define MD_RECOVERY_FROZEN 9
290 unsigned long recovery;
291 /* If a RAID personality determines that recovery (of a particular
292 * device) will fail due to a read error on the source device, it
293 * takes a copy of this number and does not attempt recovery again
294 * until this number changes.
296 int recovery_disabled;
298 int in_sync; /* know to not need resync */
299 /* 'open_mutex' avoids races between 'md_open' and 'do_md_stop', so
300 * that we are never stopping an array while it is open.
301 * 'reconfig_mutex' protects all other reconfiguration.
302 * These locks are separate due to conflicting interactions
303 * with bdev->bd_mutex.
305 * reconfig_mutex -> bd_mutex : e.g. do_md_run -> revalidate_disk
306 * bd_mutex -> open_mutex: e.g. __blkdev_get -> md_open
308 struct mutex open_mutex;
309 struct mutex reconfig_mutex;
310 atomic_t active; /* general refcount */
311 atomic_t openers; /* number of active opens */
313 int changed; /* True if we might need to
314 * reread partition info */
315 int degraded; /* whether md should consider
319 atomic_t recovery_active; /* blocks scheduled, but not written */
320 wait_queue_head_t recovery_wait;
321 sector_t recovery_cp;
322 sector_t resync_min; /* user requested sync
324 sector_t resync_max; /* resync should pause
325 * when it gets here */
327 struct sysfs_dirent *sysfs_state; /* handle for 'array_state'
330 struct sysfs_dirent *sysfs_action; /* handle for 'sync_action' */
332 struct work_struct del_work; /* used for delayed sysfs removal */
334 spinlock_t write_lock;
335 wait_queue_head_t sb_wait; /* for waiting on superblock updates */
336 atomic_t pending_writes; /* number of active superblock writes */
338 unsigned int safemode; /* if set, update "clean" superblock
339 * when no writes pending.
341 unsigned int safemode_delay;
342 struct timer_list safemode_timer;
343 atomic_t writes_pending;
344 struct request_queue *queue; /* for plugging ... */
346 struct bitmap *bitmap; /* the bitmap for the device */
348 struct file *file; /* the bitmap file */
349 loff_t offset; /* offset from superblock of
350 * start of bitmap. May be
351 * negative, but not '0'
352 * For external metadata, offset
353 * from start of device.
355 loff_t default_offset; /* this is the offset to use when
356 * hot-adding a bitmap. It should
357 * eventually be settable by sysfs.
360 unsigned long chunksize;
361 unsigned long daemon_sleep; /* how many jiffies between updates? */
362 unsigned long max_write_behind; /* write-behind mode */
366 atomic_t max_corr_read_errors; /* max read retries */
367 struct list_head all_mddevs;
369 struct attribute_group *to_remove;
371 struct bio_set *bio_set;
373 /* Generic flush handling.
374 * The last to finish preflush schedules a worker to submit
375 * the rest of the request (without the REQ_FLUSH flag).
377 struct bio *flush_bio;
378 atomic_t flush_pending;
379 struct work_struct flush_work;
380 struct work_struct event_work; /* used by dm to report failure event */
381 void (*sync_super)(mddev_t *mddev, mdk_rdev_t *rdev);
385 static inline void rdev_dec_pending(mdk_rdev_t *rdev, mddev_t *mddev)
387 int faulty = test_bit(Faulty, &rdev->flags);
388 if (atomic_dec_and_test(&rdev->nr_pending) && faulty)
389 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
392 static inline void md_sync_acct(struct block_device *bdev, unsigned long nr_sectors)
394 atomic_add(nr_sectors, &bdev->bd_contains->bd_disk->sync_io);
397 struct mdk_personality
401 struct list_head list;
402 struct module *owner;
403 int (*make_request)(mddev_t *mddev, struct bio *bio);
404 int (*run)(mddev_t *mddev);
405 int (*stop)(mddev_t *mddev);
406 void (*status)(struct seq_file *seq, mddev_t *mddev);
407 /* error_handler must set ->faulty and clear ->in_sync
408 * if appropriate, and should abort recovery if needed
410 void (*error_handler)(mddev_t *mddev, mdk_rdev_t *rdev);
411 int (*hot_add_disk) (mddev_t *mddev, mdk_rdev_t *rdev);
412 int (*hot_remove_disk) (mddev_t *mddev, int number);
413 int (*spare_active) (mddev_t *mddev);
414 sector_t (*sync_request)(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster);
415 int (*resize) (mddev_t *mddev, sector_t sectors);
416 sector_t (*size) (mddev_t *mddev, sector_t sectors, int raid_disks);
417 int (*check_reshape) (mddev_t *mddev);
418 int (*start_reshape) (mddev_t *mddev);
419 void (*finish_reshape) (mddev_t *mddev);
420 /* quiesce moves between quiescence states
422 * 1 - no new requests allowed
425 void (*quiesce) (mddev_t *mddev, int state);
426 /* takeover is used to transition an array from one
427 * personality to another. The new personality must be able
428 * to handle the data in the current layout.
429 * e.g. 2drive raid1 -> 2drive raid5
430 * ndrive raid5 -> degraded n+1drive raid6 with special layout
431 * If the takeover succeeds, a new 'private' structure is returned.
432 * This needs to be installed and then ->run used to activate the
435 void *(*takeover) (mddev_t *mddev);
439 struct md_sysfs_entry {
440 struct attribute attr;
441 ssize_t (*show)(mddev_t *, char *);
442 ssize_t (*store)(mddev_t *, const char *, size_t);
444 extern struct attribute_group md_bitmap_group;
446 static inline struct sysfs_dirent *sysfs_get_dirent_safe(struct sysfs_dirent *sd, char *name)
449 return sysfs_get_dirent(sd, NULL, name);
452 static inline void sysfs_notify_dirent_safe(struct sysfs_dirent *sd)
455 sysfs_notify_dirent(sd);
458 static inline char * mdname (mddev_t * mddev)
460 return mddev->gendisk ? mddev->gendisk->disk_name : "mdX";
463 static inline int sysfs_link_rdev(mddev_t *mddev, mdk_rdev_t *rdev)
466 sprintf(nm, "rd%d", rdev->raid_disk);
467 return sysfs_create_link(&mddev->kobj, &rdev->kobj, nm);
470 static inline void sysfs_unlink_rdev(mddev_t *mddev, mdk_rdev_t *rdev)
473 sprintf(nm, "rd%d", rdev->raid_disk);
474 sysfs_remove_link(&mddev->kobj, nm);
478 * iterates through some rdev ringlist. It's safe to remove the
479 * current 'rdev'. Dont touch 'tmp' though.
481 #define rdev_for_each_list(rdev, tmp, head) \
482 list_for_each_entry_safe(rdev, tmp, head, same_set)
485 * iterates through the 'same array disks' ringlist
487 #define rdev_for_each(rdev, tmp, mddev) \
488 list_for_each_entry_safe(rdev, tmp, &((mddev)->disks), same_set)
490 #define rdev_for_each_rcu(rdev, mddev) \
491 list_for_each_entry_rcu(rdev, &((mddev)->disks), same_set)
493 typedef struct mdk_thread_s {
494 void (*run) (mddev_t *mddev);
496 wait_queue_head_t wqueue;
498 struct task_struct *tsk;
499 unsigned long timeout;
502 #define THREAD_WAKEUP 0
504 #define __wait_event_lock_irq(wq, condition, lock, cmd) \
506 wait_queue_t __wait; \
507 init_waitqueue_entry(&__wait, current); \
509 add_wait_queue(&wq, &__wait); \
511 set_current_state(TASK_UNINTERRUPTIBLE); \
514 spin_unlock_irq(&lock); \
517 spin_lock_irq(&lock); \
519 current->state = TASK_RUNNING; \
520 remove_wait_queue(&wq, &__wait); \
523 #define wait_event_lock_irq(wq, condition, lock, cmd) \
527 __wait_event_lock_irq(wq, condition, lock, cmd); \
530 static inline void safe_put_page(struct page *p)
535 extern int register_md_personality(struct mdk_personality *p);
536 extern int unregister_md_personality(struct mdk_personality *p);
537 extern mdk_thread_t * md_register_thread(void (*run) (mddev_t *mddev),
538 mddev_t *mddev, const char *name);
539 extern void md_unregister_thread(mdk_thread_t *thread);
540 extern void md_wakeup_thread(mdk_thread_t *thread);
541 extern void md_check_recovery(mddev_t *mddev);
542 extern void md_write_start(mddev_t *mddev, struct bio *bi);
543 extern void md_write_end(mddev_t *mddev);
544 extern void md_done_sync(mddev_t *mddev, int blocks, int ok);
545 extern void md_error(mddev_t *mddev, mdk_rdev_t *rdev);
547 extern int mddev_congested(mddev_t *mddev, int bits);
548 extern void md_flush_request(mddev_t *mddev, struct bio *bio);
549 extern void md_super_write(mddev_t *mddev, mdk_rdev_t *rdev,
550 sector_t sector, int size, struct page *page);
551 extern void md_super_wait(mddev_t *mddev);
552 extern int sync_page_io(mdk_rdev_t *rdev, sector_t sector, int size,
553 struct page *page, int rw, bool metadata_op);
554 extern void md_do_sync(mddev_t *mddev);
555 extern void md_new_event(mddev_t *mddev);
556 extern int md_allow_write(mddev_t *mddev);
557 extern void md_wait_for_blocked_rdev(mdk_rdev_t *rdev, mddev_t *mddev);
558 extern void md_set_array_sectors(mddev_t *mddev, sector_t array_sectors);
559 extern int md_check_no_bitmap(mddev_t *mddev);
560 extern int md_integrity_register(mddev_t *mddev);
561 extern void md_integrity_add_rdev(mdk_rdev_t *rdev, mddev_t *mddev);
562 extern int strict_strtoul_scaled(const char *cp, unsigned long *res, int scale);
563 extern void restore_bitmap_write_access(struct file *file);
565 extern void mddev_init(mddev_t *mddev);
566 extern int md_run(mddev_t *mddev);
567 extern void md_stop(mddev_t *mddev);
568 extern void md_stop_writes(mddev_t *mddev);
569 extern int md_rdev_init(mdk_rdev_t *rdev);
571 extern void mddev_suspend(mddev_t *mddev);
572 extern void mddev_resume(mddev_t *mddev);
573 extern struct bio *bio_clone_mddev(struct bio *bio, gfp_t gfp_mask,
575 extern struct bio *bio_alloc_mddev(gfp_t gfp_mask, int nr_iovecs,
577 extern int mddev_check_plugged(mddev_t *mddev);
578 extern void md_trim_bio(struct bio *bio, int offset, int size);
579 #endif /* _MD_MD_H */