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 /* generic plugging support - like that provided with request_queue,
33 * but does not require a request_queue
36 void (*unplug_fn)(struct plug_handle *);
37 struct timer_list unplug_timer;
38 struct work_struct unplug_work;
39 unsigned long unplug_flag;
41 #define PLUGGED_FLAG 1
42 void plugger_init(struct plug_handle *plug,
43 void (*unplug_fn)(struct plug_handle *));
44 void plugger_set_plug(struct plug_handle *plug);
45 int plugger_remove_plug(struct plug_handle *plug);
46 static inline void plugger_flush(struct plug_handle *plug)
48 del_timer_sync(&plug->unplug_timer);
49 cancel_work_sync(&plug->unplug_work);
53 * MD's 'extended' device
57 struct list_head same_set; /* RAID devices within the same set */
59 sector_t sectors; /* Device size (in 512bytes sectors) */
60 mddev_t *mddev; /* RAID array if running */
61 int last_events; /* IO event timestamp */
64 * If meta_bdev is non-NULL, it means that a separate device is
65 * being used to store the metadata (superblock/bitmap) which
66 * would otherwise be contained on the same device as the data (bdev).
68 struct block_device *meta_bdev;
69 struct block_device *bdev; /* block device handle */
74 sector_t data_offset; /* start of data in array */
75 sector_t sb_start; /* offset of the super block (in 512byte sectors) */
76 int sb_size; /* bytes in the superblock */
77 int preferred_minor; /* autorun support */
81 /* A device can be in one of three states based on two flags:
82 * Not working: faulty==1 in_sync==0
83 * Fully working: faulty==0 in_sync==1
86 * faulty==0 in_sync==0
88 * It can never have faulty==1, in_sync==1
89 * This reduces the burden of testing multiple flags in many cases
93 #define Faulty 1 /* device is known to have a fault */
94 #define In_sync 2 /* device is in_sync with rest of array */
95 #define WriteMostly 4 /* Avoid reading if at all possible */
96 #define AllReserved 6 /* If whole device is reserved for
98 #define AutoDetected 7 /* added by auto-detect */
99 #define Blocked 8 /* An error occured on an externally
100 * managed array, don't allow writes
101 * until it is cleared */
102 wait_queue_head_t blocked_wait;
104 int desc_nr; /* descriptor index in the superblock */
105 int raid_disk; /* role of device in array */
106 int new_raid_disk; /* role that the device will have in
107 * the array after a level-change completes.
109 int saved_raid_disk; /* role that device used to have in the
110 * array and could again if we did a partial
111 * resync from the bitmap
113 sector_t recovery_offset;/* If this device has been partially
114 * recovered, this is where we were
118 atomic_t nr_pending; /* number of pending requests.
119 * only maintained for arrays that
120 * support hot removal
122 atomic_t read_errors; /* number of consecutive read errors that
123 * we have tried to ignore.
125 struct timespec last_read_error; /* monotonic time since our
128 atomic_t corrected_errors; /* number of corrected read errors,
129 * for reporting to userspace and storing
132 struct work_struct del_work; /* used for delayed sysfs removal */
134 struct sysfs_dirent *sysfs_state; /* handle for 'state'
141 struct mdk_personality *pers;
144 struct list_head disks;
146 #define MD_CHANGE_DEVS 0 /* Some device status has changed */
147 #define MD_CHANGE_CLEAN 1 /* transition to or from 'clean' */
148 #define MD_CHANGE_PENDING 2 /* switch from 'clean' to 'active' in progress */
153 int sysfs_active; /* set when sysfs deletes
154 * are happening, so run/
155 * takeover/stop are not safe
157 int ready; /* See when safe to pass
158 * IO requests down */
159 struct gendisk *gendisk;
163 #define UNTIL_IOCTL 1
166 /* Superblock information */
171 int external; /* metadata is
172 * managed externally */
173 char metadata_type[17]; /* externally set*/
180 sector_t dev_sectors; /* used size of
181 * component devices */
182 sector_t array_sectors; /* exported array size */
183 int external_size; /* size managed
186 /* If the last 'event' was simply a clean->dirty transition, and
187 * we didn't write it to the spares, then it is safe and simple
188 * to just decrement the event count on a dirty->clean transition.
189 * So we record that possibility here.
191 int can_decrease_events;
195 /* If the array is being reshaped, we need to record the
196 * new shape and an indication of where we are up to.
197 * This is written to the superblock.
198 * If reshape_position is MaxSector, then no reshape is happening (yet).
200 sector_t reshape_position;
201 int delta_disks, new_level, new_layout;
202 int new_chunk_sectors;
204 struct mdk_thread_s *thread; /* management thread */
205 struct mdk_thread_s *sync_thread; /* doing resync or reconstruct */
206 sector_t curr_resync; /* last block scheduled */
207 /* As resync requests can complete out of order, we cannot easily track
208 * how much resync has been completed. So we occasionally pause until
209 * everything completes, then set curr_resync_completed to curr_resync.
210 * As such it may be well behind the real resync mark, but it is a value
213 sector_t curr_resync_completed;
214 unsigned long resync_mark; /* a recent timestamp */
215 sector_t resync_mark_cnt;/* blocks written at resync_mark */
216 sector_t curr_mark_cnt; /* blocks scheduled now */
218 sector_t resync_max_sectors; /* may be set by personality */
220 sector_t resync_mismatches; /* count of sectors where
221 * parity/replica mismatch found
224 /* allow user-space to request suspension of IO to regions of the array */
227 /* if zero, use the system-wide default */
231 /* resync even though the same disks are shared among md-devices */
234 int ok_start_degraded;
235 /* recovery/resync flags
236 * NEEDED: we might need to start a resync/recover
237 * RUNNING: a thread is running, or about to be started
238 * SYNC: actually doing a resync, not a recovery
239 * RECOVER: doing recovery, or need to try it.
240 * INTR: resync needs to be aborted for some reason
241 * DONE: thread is done and is waiting to be reaped
242 * REQUEST: user-space has requested a sync (used with SYNC)
243 * CHECK: user-space request for check-only, no repair
244 * RESHAPE: A reshape is happening
246 * If neither SYNC or RESHAPE are set, then it is a recovery.
248 #define MD_RECOVERY_RUNNING 0
249 #define MD_RECOVERY_SYNC 1
250 #define MD_RECOVERY_RECOVER 2
251 #define MD_RECOVERY_INTR 3
252 #define MD_RECOVERY_DONE 4
253 #define MD_RECOVERY_NEEDED 5
254 #define MD_RECOVERY_REQUESTED 6
255 #define MD_RECOVERY_CHECK 7
256 #define MD_RECOVERY_RESHAPE 8
257 #define MD_RECOVERY_FROZEN 9
259 unsigned long recovery;
260 int recovery_disabled; /* if we detect that recovery
261 * will always fail, set this
262 * so we don't loop trying */
264 int in_sync; /* know to not need resync */
265 /* 'open_mutex' avoids races between 'md_open' and 'do_md_stop', so
266 * that we are never stopping an array while it is open.
267 * 'reconfig_mutex' protects all other reconfiguration.
268 * These locks are separate due to conflicting interactions
269 * with bdev->bd_mutex.
271 * reconfig_mutex -> bd_mutex : e.g. do_md_run -> revalidate_disk
272 * bd_mutex -> open_mutex: e.g. __blkdev_get -> md_open
274 struct mutex open_mutex;
275 struct mutex reconfig_mutex;
276 atomic_t active; /* general refcount */
277 atomic_t openers; /* number of active opens */
279 int degraded; /* whether md should consider
283 atomic_t recovery_active; /* blocks scheduled, but not written */
284 wait_queue_head_t recovery_wait;
285 sector_t recovery_cp;
286 sector_t resync_min; /* user requested sync
288 sector_t resync_max; /* resync should pause
289 * when it gets here */
291 struct sysfs_dirent *sysfs_state; /* handle for 'array_state'
294 struct sysfs_dirent *sysfs_action; /* handle for 'sync_action' */
296 struct work_struct del_work; /* used for delayed sysfs removal */
298 spinlock_t write_lock;
299 wait_queue_head_t sb_wait; /* for waiting on superblock updates */
300 atomic_t pending_writes; /* number of active superblock writes */
302 unsigned int safemode; /* if set, update "clean" superblock
303 * when no writes pending.
305 unsigned int safemode_delay;
306 struct timer_list safemode_timer;
307 atomic_t writes_pending;
308 struct request_queue *queue; /* for plugging ... */
310 struct bitmap *bitmap; /* the bitmap for the device */
312 struct file *file; /* the bitmap file */
313 loff_t offset; /* offset from superblock of
314 * start of bitmap. May be
315 * negative, but not '0'
316 * For external metadata, offset
317 * from start of device.
319 loff_t default_offset; /* this is the offset to use when
320 * hot-adding a bitmap. It should
321 * eventually be settable by sysfs.
323 /* When md is serving under dm, it might use a
324 * dirty_log to store the bits.
326 struct dm_dirty_log *log;
329 unsigned long chunksize;
330 unsigned long daemon_sleep; /* how many jiffies between updates? */
331 unsigned long max_write_behind; /* write-behind mode */
335 atomic_t max_corr_read_errors; /* max read retries */
336 struct list_head all_mddevs;
338 struct attribute_group *to_remove;
339 struct plug_handle *plug; /* if used by personality */
341 struct bio_set *bio_set;
343 /* Generic flush handling.
344 * The last to finish preflush schedules a worker to submit
345 * the rest of the request (without the REQ_FLUSH flag).
347 struct bio *flush_bio;
348 atomic_t flush_pending;
349 struct work_struct flush_work;
350 struct work_struct event_work; /* used by dm to report failure event */
354 static inline void rdev_dec_pending(mdk_rdev_t *rdev, mddev_t *mddev)
356 int faulty = test_bit(Faulty, &rdev->flags);
357 if (atomic_dec_and_test(&rdev->nr_pending) && faulty)
358 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
361 static inline void md_sync_acct(struct block_device *bdev, unsigned long nr_sectors)
363 atomic_add(nr_sectors, &bdev->bd_contains->bd_disk->sync_io);
366 struct mdk_personality
370 struct list_head list;
371 struct module *owner;
372 int (*make_request)(mddev_t *mddev, struct bio *bio);
373 int (*run)(mddev_t *mddev);
374 int (*stop)(mddev_t *mddev);
375 void (*status)(struct seq_file *seq, mddev_t *mddev);
376 /* error_handler must set ->faulty and clear ->in_sync
377 * if appropriate, and should abort recovery if needed
379 void (*error_handler)(mddev_t *mddev, mdk_rdev_t *rdev);
380 int (*hot_add_disk) (mddev_t *mddev, mdk_rdev_t *rdev);
381 int (*hot_remove_disk) (mddev_t *mddev, int number);
382 int (*spare_active) (mddev_t *mddev);
383 sector_t (*sync_request)(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster);
384 int (*resize) (mddev_t *mddev, sector_t sectors);
385 sector_t (*size) (mddev_t *mddev, sector_t sectors, int raid_disks);
386 int (*check_reshape) (mddev_t *mddev);
387 int (*start_reshape) (mddev_t *mddev);
388 void (*finish_reshape) (mddev_t *mddev);
389 /* quiesce moves between quiescence states
391 * 1 - no new requests allowed
394 void (*quiesce) (mddev_t *mddev, int state);
395 /* takeover is used to transition an array from one
396 * personality to another. The new personality must be able
397 * to handle the data in the current layout.
398 * e.g. 2drive raid1 -> 2drive raid5
399 * ndrive raid5 -> degraded n+1drive raid6 with special layout
400 * If the takeover succeeds, a new 'private' structure is returned.
401 * This needs to be installed and then ->run used to activate the
404 void *(*takeover) (mddev_t *mddev);
408 struct md_sysfs_entry {
409 struct attribute attr;
410 ssize_t (*show)(mddev_t *, char *);
411 ssize_t (*store)(mddev_t *, const char *, size_t);
413 extern struct attribute_group md_bitmap_group;
415 static inline struct sysfs_dirent *sysfs_get_dirent_safe(struct sysfs_dirent *sd, char *name)
418 return sysfs_get_dirent(sd, NULL, name);
421 static inline void sysfs_notify_dirent_safe(struct sysfs_dirent *sd)
424 sysfs_notify_dirent(sd);
427 static inline char * mdname (mddev_t * mddev)
429 return mddev->gendisk ? mddev->gendisk->disk_name : "mdX";
433 * iterates through some rdev ringlist. It's safe to remove the
434 * current 'rdev'. Dont touch 'tmp' though.
436 #define rdev_for_each_list(rdev, tmp, head) \
437 list_for_each_entry_safe(rdev, tmp, head, same_set)
440 * iterates through the 'same array disks' ringlist
442 #define rdev_for_each(rdev, tmp, mddev) \
443 list_for_each_entry_safe(rdev, tmp, &((mddev)->disks), same_set)
445 #define rdev_for_each_rcu(rdev, mddev) \
446 list_for_each_entry_rcu(rdev, &((mddev)->disks), same_set)
448 typedef struct mdk_thread_s {
449 void (*run) (mddev_t *mddev);
451 wait_queue_head_t wqueue;
453 struct task_struct *tsk;
454 unsigned long timeout;
457 #define THREAD_WAKEUP 0
459 #define __wait_event_lock_irq(wq, condition, lock, cmd) \
461 wait_queue_t __wait; \
462 init_waitqueue_entry(&__wait, current); \
464 add_wait_queue(&wq, &__wait); \
466 set_current_state(TASK_UNINTERRUPTIBLE); \
469 spin_unlock_irq(&lock); \
472 spin_lock_irq(&lock); \
474 current->state = TASK_RUNNING; \
475 remove_wait_queue(&wq, &__wait); \
478 #define wait_event_lock_irq(wq, condition, lock, cmd) \
482 __wait_event_lock_irq(wq, condition, lock, cmd); \
485 static inline void safe_put_page(struct page *p)
490 extern int register_md_personality(struct mdk_personality *p);
491 extern int unregister_md_personality(struct mdk_personality *p);
492 extern mdk_thread_t * md_register_thread(void (*run) (mddev_t *mddev),
493 mddev_t *mddev, const char *name);
494 extern void md_unregister_thread(mdk_thread_t *thread);
495 extern void md_wakeup_thread(mdk_thread_t *thread);
496 extern void md_check_recovery(mddev_t *mddev);
497 extern void md_write_start(mddev_t *mddev, struct bio *bi);
498 extern void md_write_end(mddev_t *mddev);
499 extern void md_done_sync(mddev_t *mddev, int blocks, int ok);
500 extern void md_error(mddev_t *mddev, mdk_rdev_t *rdev);
502 extern int mddev_congested(mddev_t *mddev, int bits);
503 extern void md_flush_request(mddev_t *mddev, struct bio *bio);
504 extern void md_super_write(mddev_t *mddev, mdk_rdev_t *rdev,
505 sector_t sector, int size, struct page *page);
506 extern void md_super_wait(mddev_t *mddev);
507 extern int sync_page_io(mdk_rdev_t *rdev, sector_t sector, int size,
508 struct page *page, int rw, bool metadata_op);
509 extern void md_do_sync(mddev_t *mddev);
510 extern void md_new_event(mddev_t *mddev);
511 extern int md_allow_write(mddev_t *mddev);
512 extern void md_wait_for_blocked_rdev(mdk_rdev_t *rdev, mddev_t *mddev);
513 extern void md_set_array_sectors(mddev_t *mddev, sector_t array_sectors);
514 extern int md_check_no_bitmap(mddev_t *mddev);
515 extern int md_integrity_register(mddev_t *mddev);
516 extern void md_integrity_add_rdev(mdk_rdev_t *rdev, mddev_t *mddev);
517 extern int strict_strtoul_scaled(const char *cp, unsigned long *res, int scale);
518 extern void restore_bitmap_write_access(struct file *file);
519 extern void md_unplug(mddev_t *mddev);
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 #endif /* _MD_MD_H */