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 * options passed in raidrun:
36 /* Currently this must fit in an 'int' */
37 #define MAX_CHUNK_SIZE (1<<30)
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 */
50 struct block_device
*bdev
; /* block device handle */
55 sector_t data_offset
; /* start of data in array */
56 sector_t sb_start
; /* offset of the super block (in 512byte sectors) */
57 int sb_size
; /* bytes in the superblock */
58 int preferred_minor
; /* autorun support */
62 /* A device can be in one of three states based on two flags:
63 * Not working: faulty==1 in_sync==0
64 * Fully working: faulty==0 in_sync==1
67 * faulty==0 in_sync==0
69 * It can never have faulty==1, in_sync==1
70 * This reduces the burden of testing multiple flags in many cases
74 #define Faulty 1 /* device is known to have a fault */
75 #define In_sync 2 /* device is in_sync with rest of array */
76 #define WriteMostly 4 /* Avoid reading if at all possible */
77 #define BarriersNotsupp 5 /* BIO_RW_BARRIER is not supported */
78 #define AllReserved 6 /* If whole device is reserved for
80 #define AutoDetected 7 /* added by auto-detect */
81 #define Blocked 8 /* An error occured on an externally
82 * managed array, don't allow writes
83 * until it is cleared */
84 #define StateChanged 9 /* Faulty or Blocked has changed during
85 * interrupt, so it needs to be
86 * notified by the thread */
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 saved_raid_disk
; /* role that device used to have in the
92 * array and could again if we did a partial
93 * resync from the bitmap
95 sector_t recovery_offset
;/* If this device has been partially
96 * recovered, this is where we were
100 atomic_t nr_pending
; /* number of pending requests.
101 * only maintained for arrays that
102 * support hot removal
104 atomic_t read_errors
; /* number of consecutive read errors that
105 * we have tried to ignore.
107 atomic_t corrected_errors
; /* number of corrected read errors,
108 * for reporting to userspace and storing
111 struct work_struct del_work
; /* used for delayed sysfs removal */
113 struct sysfs_dirent
*sysfs_state
; /* handle for 'state'
120 struct mdk_personality
*pers
;
123 struct list_head disks
;
125 #define MD_CHANGE_DEVS 0 /* Some device status has changed */
126 #define MD_CHANGE_CLEAN 1 /* transition to or from 'clean' */
127 #define MD_CHANGE_PENDING 2 /* superblock update in progress */
133 struct gendisk
*gendisk
;
137 #define UNTIL_IOCTL 1
140 /* Superblock information */
145 int external
; /* metadata is
146 * managed externally */
147 char metadata_type
[17]; /* externally set*/
154 sector_t dev_sectors
; /* used size of
155 * component devices */
156 sector_t array_sectors
; /* exported array size */
157 int external_size
; /* size managed
163 /* If the array is being reshaped, we need to record the
164 * new shape and an indication of where we are up to.
165 * This is written to the superblock.
166 * If reshape_position is MaxSector, then no reshape is happening (yet).
168 sector_t reshape_position
;
169 int delta_disks
, new_level
, new_layout
;
170 int new_chunk_sectors
;
172 struct mdk_thread_s
*thread
; /* management thread */
173 struct mdk_thread_s
*sync_thread
; /* doing resync or reconstruct */
174 sector_t curr_resync
; /* last block scheduled */
175 /* As resync requests can complete out of order, we cannot easily track
176 * how much resync has been completed. So we occasionally pause until
177 * everything completes, then set curr_resync_completed to curr_resync.
178 * As such it may be well behind the real resync mark, but it is a value
181 sector_t curr_resync_completed
;
182 unsigned long resync_mark
; /* a recent timestamp */
183 sector_t resync_mark_cnt
;/* blocks written at resync_mark */
184 sector_t curr_mark_cnt
; /* blocks scheduled now */
186 sector_t resync_max_sectors
; /* may be set by personality */
188 sector_t resync_mismatches
; /* count of sectors where
189 * parity/replica mismatch found
192 /* allow user-space to request suspension of IO to regions of the array */
195 /* if zero, use the system-wide default */
199 /* resync even though the same disks are shared among md-devices */
202 int ok_start_degraded
;
203 /* recovery/resync flags
204 * NEEDED: we might need to start a resync/recover
205 * RUNNING: a thread is running, or about to be started
206 * SYNC: actually doing a resync, not a recovery
207 * RECOVER: doing recovery, or need to try it.
208 * INTR: resync needs to be aborted for some reason
209 * DONE: thread is done and is waiting to be reaped
210 * REQUEST: user-space has requested a sync (used with SYNC)
211 * CHECK: user-space request for for check-only, no repair
212 * RESHAPE: A reshape is happening
214 * If neither SYNC or RESHAPE are set, then it is a recovery.
216 #define MD_RECOVERY_RUNNING 0
217 #define MD_RECOVERY_SYNC 1
218 #define MD_RECOVERY_RECOVER 2
219 #define MD_RECOVERY_INTR 3
220 #define MD_RECOVERY_DONE 4
221 #define MD_RECOVERY_NEEDED 5
222 #define MD_RECOVERY_REQUESTED 6
223 #define MD_RECOVERY_CHECK 7
224 #define MD_RECOVERY_RESHAPE 8
225 #define MD_RECOVERY_FROZEN 9
227 unsigned long recovery
;
228 int recovery_disabled
; /* if we detect that recovery
229 * will always fail, set this
230 * so we don't loop trying */
232 int in_sync
; /* know to not need resync */
233 struct mutex reconfig_mutex
;
234 atomic_t active
; /* general refcount */
235 atomic_t openers
; /* number of active opens */
237 int changed
; /* true if we might need to reread partition info */
238 int degraded
; /* whether md should consider
241 int barriers_work
; /* initialised to true, cleared as soon
242 * as a barrier request to slave
243 * fails. Only supported
245 struct bio
*biolist
; /* bios that need to be retried
246 * because BIO_RW_BARRIER is not supported
249 atomic_t recovery_active
; /* blocks scheduled, but not written */
250 wait_queue_head_t recovery_wait
;
251 sector_t recovery_cp
;
252 sector_t resync_min
; /* user requested sync
254 sector_t resync_max
; /* resync should pause
255 * when it gets here */
257 struct sysfs_dirent
*sysfs_state
; /* handle for 'array_state'
260 struct sysfs_dirent
*sysfs_action
; /* handle for 'sync_action' */
262 struct work_struct del_work
; /* used for delayed sysfs removal */
264 spinlock_t write_lock
;
265 wait_queue_head_t sb_wait
; /* for waiting on superblock updates */
266 atomic_t pending_writes
; /* number of active superblock writes */
268 unsigned int safemode
; /* if set, update "clean" superblock
269 * when no writes pending.
271 unsigned int safemode_delay
;
272 struct timer_list safemode_timer
;
273 atomic_t writes_pending
;
274 struct request_queue
*queue
; /* for plugging ... */
276 atomic_t write_behind
; /* outstanding async IO */
277 unsigned int max_write_behind
; /* 0 = sync */
279 struct bitmap
*bitmap
; /* the bitmap for the device */
280 struct file
*bitmap_file
; /* the bitmap file */
281 long bitmap_offset
; /* offset from superblock of
282 * start of bitmap. May be
283 * negative, but not '0'
285 long default_bitmap_offset
; /* this is the offset to use when
286 * hot-adding a bitmap. It should
287 * eventually be settable by sysfs.
290 struct list_head all_mddevs
;
294 static inline void rdev_dec_pending(mdk_rdev_t
*rdev
, mddev_t
*mddev
)
296 int faulty
= test_bit(Faulty
, &rdev
->flags
);
297 if (atomic_dec_and_test(&rdev
->nr_pending
) && faulty
)
298 set_bit(MD_RECOVERY_NEEDED
, &mddev
->recovery
);
301 static inline void md_sync_acct(struct block_device
*bdev
, unsigned long nr_sectors
)
303 atomic_add(nr_sectors
, &bdev
->bd_contains
->bd_disk
->sync_io
);
306 struct mdk_personality
310 struct list_head list
;
311 struct module
*owner
;
312 int (*make_request
)(struct request_queue
*q
, struct bio
*bio
);
313 int (*run
)(mddev_t
*mddev
);
314 int (*stop
)(mddev_t
*mddev
);
315 void (*status
)(struct seq_file
*seq
, mddev_t
*mddev
);
316 /* error_handler must set ->faulty and clear ->in_sync
317 * if appropriate, and should abort recovery if needed
319 void (*error_handler
)(mddev_t
*mddev
, mdk_rdev_t
*rdev
);
320 int (*hot_add_disk
) (mddev_t
*mddev
, mdk_rdev_t
*rdev
);
321 int (*hot_remove_disk
) (mddev_t
*mddev
, int number
);
322 int (*spare_active
) (mddev_t
*mddev
);
323 sector_t (*sync_request
)(mddev_t
*mddev
, sector_t sector_nr
, int *skipped
, int go_faster
);
324 int (*resize
) (mddev_t
*mddev
, sector_t sectors
);
325 sector_t (*size
) (mddev_t
*mddev
, sector_t sectors
, int raid_disks
);
326 int (*check_reshape
) (mddev_t
*mddev
);
327 int (*start_reshape
) (mddev_t
*mddev
);
328 void (*finish_reshape
) (mddev_t
*mddev
);
329 int (*reconfig
) (mddev_t
*mddev
, int layout
, int chunk_size
);
330 /* quiesce moves between quiescence states
332 * 1 - no new requests allowed
335 void (*quiesce
) (mddev_t
*mddev
, int state
);
336 /* takeover is used to transition an array from one
337 * personality to another. The new personality must be able
338 * to handle the data in the current layout.
339 * e.g. 2drive raid1 -> 2drive raid5
340 * ndrive raid5 -> degraded n+1drive raid6 with special layout
341 * If the takeover succeeds, a new 'private' structure is returned.
342 * This needs to be installed and then ->run used to activate the
345 void *(*takeover
) (mddev_t
*mddev
);
349 struct md_sysfs_entry
{
350 struct attribute attr
;
351 ssize_t (*show
)(mddev_t
*, char *);
352 ssize_t (*store
)(mddev_t
*, const char *, size_t);
356 static inline char * mdname (mddev_t
* mddev
)
358 return mddev
->gendisk
? mddev
->gendisk
->disk_name
: "mdX";
362 * iterates through some rdev ringlist. It's safe to remove the
363 * current 'rdev'. Dont touch 'tmp' though.
365 #define rdev_for_each_list(rdev, tmp, head) \
366 list_for_each_entry_safe(rdev, tmp, head, same_set)
369 * iterates through the 'same array disks' ringlist
371 #define rdev_for_each(rdev, tmp, mddev) \
372 list_for_each_entry_safe(rdev, tmp, &((mddev)->disks), same_set)
374 #define rdev_for_each_rcu(rdev, mddev) \
375 list_for_each_entry_rcu(rdev, &((mddev)->disks), same_set)
377 typedef struct mdk_thread_s
{
378 void (*run
) (mddev_t
*mddev
);
380 wait_queue_head_t wqueue
;
382 struct task_struct
*tsk
;
383 unsigned long timeout
;
386 #define THREAD_WAKEUP 0
388 #define __wait_event_lock_irq(wq, condition, lock, cmd) \
390 wait_queue_t __wait; \
391 init_waitqueue_entry(&__wait, current); \
393 add_wait_queue(&wq, &__wait); \
395 set_current_state(TASK_UNINTERRUPTIBLE); \
398 spin_unlock_irq(&lock); \
401 spin_lock_irq(&lock); \
403 current->state = TASK_RUNNING; \
404 remove_wait_queue(&wq, &__wait); \
407 #define wait_event_lock_irq(wq, condition, lock, cmd) \
411 __wait_event_lock_irq(wq, condition, lock, cmd); \
414 static inline void safe_put_page(struct page
*p
)
419 extern int register_md_personality(struct mdk_personality
*p
);
420 extern int unregister_md_personality(struct mdk_personality
*p
);
421 extern mdk_thread_t
* md_register_thread(void (*run
) (mddev_t
*mddev
),
422 mddev_t
*mddev
, const char *name
);
423 extern void md_unregister_thread(mdk_thread_t
*thread
);
424 extern void md_wakeup_thread(mdk_thread_t
*thread
);
425 extern void md_check_recovery(mddev_t
*mddev
);
426 extern void md_write_start(mddev_t
*mddev
, struct bio
*bi
);
427 extern void md_write_end(mddev_t
*mddev
);
428 extern void md_done_sync(mddev_t
*mddev
, int blocks
, int ok
);
429 extern void md_error(mddev_t
*mddev
, mdk_rdev_t
*rdev
);
431 extern void md_super_write(mddev_t
*mddev
, mdk_rdev_t
*rdev
,
432 sector_t sector
, int size
, struct page
*page
);
433 extern void md_super_wait(mddev_t
*mddev
);
434 extern int sync_page_io(struct block_device
*bdev
, sector_t sector
, int size
,
435 struct page
*page
, int rw
);
436 extern void md_do_sync(mddev_t
*mddev
);
437 extern void md_new_event(mddev_t
*mddev
);
438 extern int md_allow_write(mddev_t
*mddev
);
439 extern void md_wait_for_blocked_rdev(mdk_rdev_t
*rdev
, mddev_t
*mddev
);
440 extern void md_set_array_sectors(mddev_t
*mddev
, sector_t array_sectors
);
442 #endif /* _MD_MD_H */