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
;
33 * MD's 'extended' device
37 struct list_head same_set
; /* RAID devices within the same set */
39 sector_t sectors
; /* Device size (in 512bytes sectors) */
40 mddev_t
*mddev
; /* RAID array if running */
41 int last_events
; /* IO event timestamp */
44 * If meta_bdev is non-NULL, it means that a separate device is
45 * being used to store the metadata (superblock/bitmap) which
46 * would otherwise be contained on the same device as the data (bdev).
48 struct block_device
*meta_bdev
;
49 struct block_device
*bdev
; /* block device handle */
54 sector_t data_offset
; /* start of data in array */
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 */
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
66 * faulty==0 in_sync==0
68 * It can never have faulty==1, in_sync==1
69 * This reduces the burden of testing multiple flags in many cases
73 #define Faulty 1 /* device is known to have a fault */
74 #define In_sync 2 /* device is in_sync with rest of array */
75 #define WriteMostly 4 /* Avoid reading if at all possible */
76 #define AutoDetected 7 /* added by auto-detect */
77 #define Blocked 8 /* An error occurred on an externally
78 * managed array, don't allow writes
79 * until it is cleared */
80 wait_queue_head_t blocked_wait
;
82 int desc_nr
; /* descriptor index in the superblock */
83 int raid_disk
; /* role of device in array */
84 int new_raid_disk
; /* role that the device will have in
85 * the array after a level-change completes.
87 int saved_raid_disk
; /* role that device used to have in the
88 * array and could again if we did a partial
89 * resync from the bitmap
91 sector_t recovery_offset
;/* If this device has been partially
92 * recovered, this is where we were
96 atomic_t nr_pending
; /* number of pending requests.
97 * only maintained for arrays that
100 atomic_t read_errors
; /* number of consecutive read errors that
101 * we have tried to ignore.
103 struct timespec last_read_error
; /* monotonic time since our
106 atomic_t corrected_errors
; /* number of corrected read errors,
107 * for reporting to userspace and storing
110 struct work_struct del_work
; /* used for delayed sysfs removal */
112 struct sysfs_dirent
*sysfs_state
; /* handle for 'state'
119 struct mdk_personality
*pers
;
122 struct list_head disks
;
124 #define MD_CHANGE_DEVS 0 /* Some device status has changed */
125 #define MD_CHANGE_CLEAN 1 /* transition to or from 'clean' */
126 #define MD_CHANGE_PENDING 2 /* switch from 'clean' to 'active' in progress */
127 #define MD_ARRAY_FIRST_USE 3 /* First use of array, needs initialization */
132 int sysfs_active
; /* set when sysfs deletes
133 * are happening, so run/
134 * takeover/stop are not safe
136 int ready
; /* See when safe to pass
137 * IO requests down */
138 struct gendisk
*gendisk
;
142 #define UNTIL_IOCTL 1
145 /* Superblock information */
150 int external
; /* metadata is
151 * managed externally */
152 char metadata_type
[17]; /* externally set*/
159 sector_t dev_sectors
; /* used size of
160 * component devices */
161 sector_t array_sectors
; /* exported array size */
162 int external_size
; /* size managed
165 /* If the last 'event' was simply a clean->dirty transition, and
166 * we didn't write it to the spares, then it is safe and simple
167 * to just decrement the event count on a dirty->clean transition.
168 * So we record that possibility here.
170 int can_decrease_events
;
174 /* If the array is being reshaped, we need to record the
175 * new shape and an indication of where we are up to.
176 * This is written to the superblock.
177 * If reshape_position is MaxSector, then no reshape is happening (yet).
179 sector_t reshape_position
;
180 int delta_disks
, new_level
, new_layout
;
181 int new_chunk_sectors
;
183 atomic_t plug_cnt
; /* If device is expecting
186 struct mdk_thread_s
*thread
; /* management thread */
187 struct mdk_thread_s
*sync_thread
; /* doing resync or reconstruct */
188 sector_t curr_resync
; /* last block scheduled */
189 /* As resync requests can complete out of order, we cannot easily track
190 * how much resync has been completed. So we occasionally pause until
191 * everything completes, then set curr_resync_completed to curr_resync.
192 * As such it may be well behind the real resync mark, but it is a value
195 sector_t curr_resync_completed
;
196 unsigned long resync_mark
; /* a recent timestamp */
197 sector_t resync_mark_cnt
;/* blocks written at resync_mark */
198 sector_t curr_mark_cnt
; /* blocks scheduled now */
200 sector_t resync_max_sectors
; /* may be set by personality */
202 sector_t resync_mismatches
; /* count of sectors where
203 * parity/replica mismatch found
206 /* allow user-space to request suspension of IO to regions of the array */
209 /* if zero, use the system-wide default */
213 /* resync even though the same disks are shared among md-devices */
216 int ok_start_degraded
;
217 /* recovery/resync flags
218 * NEEDED: we might need to start a resync/recover
219 * RUNNING: a thread is running, or about to be started
220 * SYNC: actually doing a resync, not a recovery
221 * RECOVER: doing recovery, or need to try it.
222 * INTR: resync needs to be aborted for some reason
223 * DONE: thread is done and is waiting to be reaped
224 * REQUEST: user-space has requested a sync (used with SYNC)
225 * CHECK: user-space request for check-only, no repair
226 * RESHAPE: A reshape is happening
228 * If neither SYNC or RESHAPE are set, then it is a recovery.
230 #define MD_RECOVERY_RUNNING 0
231 #define MD_RECOVERY_SYNC 1
232 #define MD_RECOVERY_RECOVER 2
233 #define MD_RECOVERY_INTR 3
234 #define MD_RECOVERY_DONE 4
235 #define MD_RECOVERY_NEEDED 5
236 #define MD_RECOVERY_REQUESTED 6
237 #define MD_RECOVERY_CHECK 7
238 #define MD_RECOVERY_RESHAPE 8
239 #define MD_RECOVERY_FROZEN 9
241 unsigned long recovery
;
242 /* If a RAID personality determines that recovery (of a particular
243 * device) will fail due to a read error on the source device, it
244 * takes a copy of this number and does not attempt recovery again
245 * until this number changes.
247 int recovery_disabled
;
249 int in_sync
; /* know to not need resync */
250 /* 'open_mutex' avoids races between 'md_open' and 'do_md_stop', so
251 * that we are never stopping an array while it is open.
252 * 'reconfig_mutex' protects all other reconfiguration.
253 * These locks are separate due to conflicting interactions
254 * with bdev->bd_mutex.
256 * reconfig_mutex -> bd_mutex : e.g. do_md_run -> revalidate_disk
257 * bd_mutex -> open_mutex: e.g. __blkdev_get -> md_open
259 struct mutex open_mutex
;
260 struct mutex reconfig_mutex
;
261 atomic_t active
; /* general refcount */
262 atomic_t openers
; /* number of active opens */
264 int changed
; /* True if we might need to
265 * reread partition info */
266 int degraded
; /* whether md should consider
270 atomic_t recovery_active
; /* blocks scheduled, but not written */
271 wait_queue_head_t recovery_wait
;
272 sector_t recovery_cp
;
273 sector_t resync_min
; /* user requested sync
275 sector_t resync_max
; /* resync should pause
276 * when it gets here */
278 struct sysfs_dirent
*sysfs_state
; /* handle for 'array_state'
281 struct sysfs_dirent
*sysfs_action
; /* handle for 'sync_action' */
283 struct work_struct del_work
; /* used for delayed sysfs removal */
285 spinlock_t write_lock
;
286 wait_queue_head_t sb_wait
; /* for waiting on superblock updates */
287 atomic_t pending_writes
; /* number of active superblock writes */
289 unsigned int safemode
; /* if set, update "clean" superblock
290 * when no writes pending.
292 unsigned int safemode_delay
;
293 struct timer_list safemode_timer
;
294 atomic_t writes_pending
;
295 struct request_queue
*queue
; /* for plugging ... */
297 struct bitmap
*bitmap
; /* the bitmap for the device */
299 struct file
*file
; /* the bitmap file */
300 loff_t offset
; /* offset from superblock of
301 * start of bitmap. May be
302 * negative, but not '0'
303 * For external metadata, offset
304 * from start of device.
306 loff_t default_offset
; /* this is the offset to use when
307 * hot-adding a bitmap. It should
308 * eventually be settable by sysfs.
310 /* When md is serving under dm, it might use a
311 * dirty_log to store the bits.
313 struct dm_dirty_log
*log
;
316 unsigned long chunksize
;
317 unsigned long daemon_sleep
; /* how many jiffies between updates? */
318 unsigned long max_write_behind
; /* write-behind mode */
322 atomic_t max_corr_read_errors
; /* max read retries */
323 struct list_head all_mddevs
;
325 struct attribute_group
*to_remove
;
327 struct bio_set
*bio_set
;
329 /* Generic flush handling.
330 * The last to finish preflush schedules a worker to submit
331 * the rest of the request (without the REQ_FLUSH flag).
333 struct bio
*flush_bio
;
334 atomic_t flush_pending
;
335 struct work_struct flush_work
;
336 struct work_struct event_work
; /* used by dm to report failure event */
337 void (*sync_super
)(mddev_t
*mddev
, mdk_rdev_t
*rdev
);
341 static inline void rdev_dec_pending(mdk_rdev_t
*rdev
, mddev_t
*mddev
)
343 int faulty
= test_bit(Faulty
, &rdev
->flags
);
344 if (atomic_dec_and_test(&rdev
->nr_pending
) && faulty
)
345 set_bit(MD_RECOVERY_NEEDED
, &mddev
->recovery
);
348 static inline void md_sync_acct(struct block_device
*bdev
, unsigned long nr_sectors
)
350 atomic_add(nr_sectors
, &bdev
->bd_contains
->bd_disk
->sync_io
);
353 struct mdk_personality
357 struct list_head list
;
358 struct module
*owner
;
359 int (*make_request
)(mddev_t
*mddev
, struct bio
*bio
);
360 int (*run
)(mddev_t
*mddev
);
361 int (*stop
)(mddev_t
*mddev
);
362 void (*status
)(struct seq_file
*seq
, mddev_t
*mddev
);
363 /* error_handler must set ->faulty and clear ->in_sync
364 * if appropriate, and should abort recovery if needed
366 void (*error_handler
)(mddev_t
*mddev
, mdk_rdev_t
*rdev
);
367 int (*hot_add_disk
) (mddev_t
*mddev
, mdk_rdev_t
*rdev
);
368 int (*hot_remove_disk
) (mddev_t
*mddev
, int number
);
369 int (*spare_active
) (mddev_t
*mddev
);
370 sector_t (*sync_request
)(mddev_t
*mddev
, sector_t sector_nr
, int *skipped
, int go_faster
);
371 int (*resize
) (mddev_t
*mddev
, sector_t sectors
);
372 sector_t (*size
) (mddev_t
*mddev
, sector_t sectors
, int raid_disks
);
373 int (*check_reshape
) (mddev_t
*mddev
);
374 int (*start_reshape
) (mddev_t
*mddev
);
375 void (*finish_reshape
) (mddev_t
*mddev
);
376 /* quiesce moves between quiescence states
378 * 1 - no new requests allowed
381 void (*quiesce
) (mddev_t
*mddev
, int state
);
382 /* takeover is used to transition an array from one
383 * personality to another. The new personality must be able
384 * to handle the data in the current layout.
385 * e.g. 2drive raid1 -> 2drive raid5
386 * ndrive raid5 -> degraded n+1drive raid6 with special layout
387 * If the takeover succeeds, a new 'private' structure is returned.
388 * This needs to be installed and then ->run used to activate the
391 void *(*takeover
) (mddev_t
*mddev
);
395 struct md_sysfs_entry
{
396 struct attribute attr
;
397 ssize_t (*show
)(mddev_t
*, char *);
398 ssize_t (*store
)(mddev_t
*, const char *, size_t);
400 extern struct attribute_group md_bitmap_group
;
402 static inline struct sysfs_dirent
*sysfs_get_dirent_safe(struct sysfs_dirent
*sd
, char *name
)
405 return sysfs_get_dirent(sd
, NULL
, name
);
408 static inline void sysfs_notify_dirent_safe(struct sysfs_dirent
*sd
)
411 sysfs_notify_dirent(sd
);
414 static inline char * mdname (mddev_t
* mddev
)
416 return mddev
->gendisk
? mddev
->gendisk
->disk_name
: "mdX";
419 static inline int sysfs_link_rdev(mddev_t
*mddev
, mdk_rdev_t
*rdev
)
422 sprintf(nm
, "rd%d", rdev
->raid_disk
);
423 return sysfs_create_link(&mddev
->kobj
, &rdev
->kobj
, nm
);
426 static inline void sysfs_unlink_rdev(mddev_t
*mddev
, mdk_rdev_t
*rdev
)
429 sprintf(nm
, "rd%d", rdev
->raid_disk
);
430 sysfs_remove_link(&mddev
->kobj
, nm
);
434 * iterates through some rdev ringlist. It's safe to remove the
435 * current 'rdev'. Dont touch 'tmp' though.
437 #define rdev_for_each_list(rdev, tmp, head) \
438 list_for_each_entry_safe(rdev, tmp, head, same_set)
441 * iterates through the 'same array disks' ringlist
443 #define rdev_for_each(rdev, tmp, mddev) \
444 list_for_each_entry_safe(rdev, tmp, &((mddev)->disks), same_set)
446 #define rdev_for_each_rcu(rdev, mddev) \
447 list_for_each_entry_rcu(rdev, &((mddev)->disks), same_set)
449 typedef struct mdk_thread_s
{
450 void (*run
) (mddev_t
*mddev
);
452 wait_queue_head_t wqueue
;
454 struct task_struct
*tsk
;
455 unsigned long timeout
;
458 #define THREAD_WAKEUP 0
460 #define __wait_event_lock_irq(wq, condition, lock, cmd) \
462 wait_queue_t __wait; \
463 init_waitqueue_entry(&__wait, current); \
465 add_wait_queue(&wq, &__wait); \
467 set_current_state(TASK_UNINTERRUPTIBLE); \
470 spin_unlock_irq(&lock); \
473 spin_lock_irq(&lock); \
475 current->state = TASK_RUNNING; \
476 remove_wait_queue(&wq, &__wait); \
479 #define wait_event_lock_irq(wq, condition, lock, cmd) \
483 __wait_event_lock_irq(wq, condition, lock, cmd); \
486 static inline void safe_put_page(struct page
*p
)
491 extern int register_md_personality(struct mdk_personality
*p
);
492 extern int unregister_md_personality(struct mdk_personality
*p
);
493 extern mdk_thread_t
* md_register_thread(void (*run
) (mddev_t
*mddev
),
494 mddev_t
*mddev
, const char *name
);
495 extern void md_unregister_thread(mdk_thread_t
*thread
);
496 extern void md_wakeup_thread(mdk_thread_t
*thread
);
497 extern void md_check_recovery(mddev_t
*mddev
);
498 extern void md_write_start(mddev_t
*mddev
, struct bio
*bi
);
499 extern void md_write_end(mddev_t
*mddev
);
500 extern void md_done_sync(mddev_t
*mddev
, int blocks
, int ok
);
501 extern void md_error(mddev_t
*mddev
, mdk_rdev_t
*rdev
);
503 extern int mddev_congested(mddev_t
*mddev
, int bits
);
504 extern void md_flush_request(mddev_t
*mddev
, struct bio
*bio
);
505 extern void md_super_write(mddev_t
*mddev
, mdk_rdev_t
*rdev
,
506 sector_t sector
, int size
, struct page
*page
);
507 extern void md_super_wait(mddev_t
*mddev
);
508 extern int sync_page_io(mdk_rdev_t
*rdev
, sector_t sector
, int size
,
509 struct page
*page
, int rw
, bool metadata_op
);
510 extern void md_do_sync(mddev_t
*mddev
);
511 extern void md_new_event(mddev_t
*mddev
);
512 extern int md_allow_write(mddev_t
*mddev
);
513 extern void md_wait_for_blocked_rdev(mdk_rdev_t
*rdev
, mddev_t
*mddev
);
514 extern void md_set_array_sectors(mddev_t
*mddev
, sector_t array_sectors
);
515 extern int md_check_no_bitmap(mddev_t
*mddev
);
516 extern int md_integrity_register(mddev_t
*mddev
);
517 extern void md_integrity_add_rdev(mdk_rdev_t
*rdev
, mddev_t
*mddev
);
518 extern int strict_strtoul_scaled(const char *cp
, unsigned long *res
, int scale
);
519 extern void restore_bitmap_write_access(struct file
*file
);
521 extern void mddev_init(mddev_t
*mddev
);
522 extern int md_run(mddev_t
*mddev
);
523 extern void md_stop(mddev_t
*mddev
);
524 extern void md_stop_writes(mddev_t
*mddev
);
525 extern void md_rdev_init(mdk_rdev_t
*rdev
);
527 extern void mddev_suspend(mddev_t
*mddev
);
528 extern void mddev_resume(mddev_t
*mddev
);
529 extern struct bio
*bio_clone_mddev(struct bio
*bio
, gfp_t gfp_mask
,
531 extern struct bio
*bio_alloc_mddev(gfp_t gfp_mask
, int nr_iovecs
,
533 extern int mddev_check_plugged(mddev_t
*mddev
);
534 #endif /* _MD_MD_H */