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.
20 #define MaxSector (~(sector_t)0)
22 typedef struct mddev_s mddev_t;
23 typedef struct mdk_rdev_s mdk_rdev_t;
26 * options passed in raidrun:
29 /* Currently this must fit in an 'int' */
30 #define MAX_CHUNK_SIZE (1<<30)
33 * MD's 'extended' device
37 struct list_head same_set; /* RAID devices within the same set */
39 sector_t size; /* Device size (in blocks) */
40 mddev_t *mddev; /* RAID array if running */
41 int last_events; /* IO event timestamp */
43 struct block_device *bdev; /* block device handle */
48 sector_t data_offset; /* start of data in array */
49 sector_t sb_start; /* offset of the super block (in 512byte sectors) */
50 int sb_size; /* bytes in the superblock */
51 int preferred_minor; /* autorun support */
55 /* A device can be in one of three states based on two flags:
56 * Not working: faulty==1 in_sync==0
57 * Fully working: faulty==0 in_sync==1
60 * faulty==0 in_sync==0
62 * It can never have faulty==1, in_sync==1
63 * This reduces the burden of testing multiple flags in many cases
67 #define Faulty 1 /* device is known to have a fault */
68 #define In_sync 2 /* device is in_sync with rest of array */
69 #define WriteMostly 4 /* Avoid reading if at all possible */
70 #define BarriersNotsupp 5 /* BIO_RW_BARRIER is not supported */
71 #define AllReserved 6 /* If whole device is reserved for
73 #define AutoDetected 7 /* added by auto-detect */
74 #define Blocked 8 /* An error occured on an externally
75 * managed array, don't allow writes
76 * until it is cleared */
77 #define StateChanged 9 /* Faulty or Blocked has changed during
78 * interrupt, so it needs to be
79 * notified by the thread */
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 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
88 sector_t recovery_offset;/* If this device has been partially
89 * recovered, this is where we were
93 atomic_t nr_pending; /* number of pending requests.
94 * only maintained for arrays that
97 atomic_t read_errors; /* number of consecutive read errors that
98 * we have tried to ignore.
100 atomic_t corrected_errors; /* number of corrected read errors,
101 * for reporting to userspace and storing
104 struct work_struct del_work; /* used for delayed sysfs removal */
106 struct sysfs_dirent *sysfs_state; /* handle for 'state'
113 struct mdk_personality *pers;
116 struct list_head disks;
118 #define MD_CHANGE_DEVS 0 /* Some device status has changed */
119 #define MD_CHANGE_CLEAN 1 /* transition to or from 'clean' */
120 #define MD_CHANGE_PENDING 2 /* superblock update in progress */
124 struct gendisk *gendisk;
128 #define UNTIL_IOCTL 1
131 /* Superblock information */
136 int external; /* metadata is
137 * managed externally */
138 char metadata_type[17]; /* externally set*/
145 sector_t dev_sectors; /* used size of
146 * component devices */
147 sector_t array_sectors; /* exported array size */
152 /* If the array is being reshaped, we need to record the
153 * new shape and an indication of where we are up to.
154 * This is written to the superblock.
155 * If reshape_position is MaxSector, then no reshape is happening (yet).
157 sector_t reshape_position;
158 int delta_disks, new_level, new_layout, new_chunk;
160 struct mdk_thread_s *thread; /* management thread */
161 struct mdk_thread_s *sync_thread; /* doing resync or reconstruct */
162 sector_t curr_resync; /* last block scheduled */
163 /* As resync requests can complete out of order, we cannot easily track
164 * how much resync has been completed. So we occasionally pause until
165 * everything completes, then set curr_resync_completed to curr_resync.
166 * As such it may be well behind the real resync mark, but it is a value
169 sector_t curr_resync_completed;
170 unsigned long resync_mark; /* a recent timestamp */
171 sector_t resync_mark_cnt;/* blocks written at resync_mark */
172 sector_t curr_mark_cnt; /* blocks scheduled now */
174 sector_t resync_max_sectors; /* may be set by personality */
176 sector_t resync_mismatches; /* count of sectors where
177 * parity/replica mismatch found
180 /* allow user-space to request suspension of IO to regions of the array */
183 /* if zero, use the system-wide default */
187 /* resync even though the same disks are shared among md-devices */
190 int ok_start_degraded;
191 /* recovery/resync flags
192 * NEEDED: we might need to start a resync/recover
193 * RUNNING: a thread is running, or about to be started
194 * SYNC: actually doing a resync, not a recovery
195 * RECOVER: doing recovery, or need to try it.
196 * INTR: resync needs to be aborted for some reason
197 * DONE: thread is done and is waiting to be reaped
198 * REQUEST: user-space has requested a sync (used with SYNC)
199 * CHECK: user-space request for for check-only, no repair
200 * RESHAPE: A reshape is happening
202 * If neither SYNC or RESHAPE are set, then it is a recovery.
204 #define MD_RECOVERY_RUNNING 0
205 #define MD_RECOVERY_SYNC 1
206 #define MD_RECOVERY_RECOVER 2
207 #define MD_RECOVERY_INTR 3
208 #define MD_RECOVERY_DONE 4
209 #define MD_RECOVERY_NEEDED 5
210 #define MD_RECOVERY_REQUESTED 6
211 #define MD_RECOVERY_CHECK 7
212 #define MD_RECOVERY_RESHAPE 8
213 #define MD_RECOVERY_FROZEN 9
215 unsigned long recovery;
216 int recovery_disabled; /* if we detect that recovery
217 * will always fail, set this
218 * so we don't loop trying */
220 int in_sync; /* know to not need resync */
221 struct mutex reconfig_mutex;
222 atomic_t active; /* general refcount */
223 atomic_t openers; /* number of active opens */
225 int changed; /* true if we might need to reread partition info */
226 int degraded; /* whether md should consider
229 int barriers_work; /* initialised to true, cleared as soon
230 * as a barrier request to slave
231 * fails. Only supported
233 struct bio *biolist; /* bios that need to be retried
234 * because BIO_RW_BARRIER is not supported
237 atomic_t recovery_active; /* blocks scheduled, but not written */
238 wait_queue_head_t recovery_wait;
239 sector_t recovery_cp;
240 sector_t resync_min; /* user requested sync
242 sector_t resync_max; /* resync should pause
243 * when it gets here */
245 struct sysfs_dirent *sysfs_state; /* handle for 'array_state'
248 struct sysfs_dirent *sysfs_action; /* handle for 'sync_action' */
250 struct work_struct del_work; /* used for delayed sysfs removal */
252 spinlock_t write_lock;
253 wait_queue_head_t sb_wait; /* for waiting on superblock updates */
254 atomic_t pending_writes; /* number of active superblock writes */
256 unsigned int safemode; /* if set, update "clean" superblock
257 * when no writes pending.
259 unsigned int safemode_delay;
260 struct timer_list safemode_timer;
261 atomic_t writes_pending;
262 struct request_queue *queue; /* for plugging ... */
264 atomic_t write_behind; /* outstanding async IO */
265 unsigned int max_write_behind; /* 0 = sync */
267 struct bitmap *bitmap; /* the bitmap for the device */
268 struct file *bitmap_file; /* the bitmap file */
269 long bitmap_offset; /* offset from superblock of
270 * start of bitmap. May be
271 * negative, but not '0'
273 long default_bitmap_offset; /* this is the offset to use when
274 * hot-adding a bitmap. It should
275 * eventually be settable by sysfs.
278 struct list_head all_mddevs;
282 static inline void rdev_dec_pending(mdk_rdev_t *rdev, mddev_t *mddev)
284 int faulty = test_bit(Faulty, &rdev->flags);
285 if (atomic_dec_and_test(&rdev->nr_pending) && faulty)
286 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
289 static inline void md_sync_acct(struct block_device *bdev, unsigned long nr_sectors)
291 atomic_add(nr_sectors, &bdev->bd_contains->bd_disk->sync_io);
294 struct mdk_personality
298 struct list_head list;
299 struct module *owner;
300 int (*make_request)(struct request_queue *q, struct bio *bio);
301 int (*run)(mddev_t *mddev);
302 int (*stop)(mddev_t *mddev);
303 void (*status)(struct seq_file *seq, mddev_t *mddev);
304 /* error_handler must set ->faulty and clear ->in_sync
305 * if appropriate, and should abort recovery if needed
307 void (*error_handler)(mddev_t *mddev, mdk_rdev_t *rdev);
308 int (*hot_add_disk) (mddev_t *mddev, mdk_rdev_t *rdev);
309 int (*hot_remove_disk) (mddev_t *mddev, int number);
310 int (*spare_active) (mddev_t *mddev);
311 sector_t (*sync_request)(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster);
312 int (*resize) (mddev_t *mddev, sector_t sectors);
313 int (*check_reshape) (mddev_t *mddev);
314 int (*start_reshape) (mddev_t *mddev);
315 int (*reconfig) (mddev_t *mddev, int layout, int chunk_size);
316 /* quiesce moves between quiescence states
318 * 1 - no new requests allowed
321 void (*quiesce) (mddev_t *mddev, int state);
325 struct md_sysfs_entry {
326 struct attribute attr;
327 ssize_t (*show)(mddev_t *, char *);
328 ssize_t (*store)(mddev_t *, const char *, size_t);
332 static inline char * mdname (mddev_t * mddev)
334 return mddev->gendisk ? mddev->gendisk->disk_name : "mdX";
338 * iterates through some rdev ringlist. It's safe to remove the
339 * current 'rdev'. Dont touch 'tmp' though.
341 #define rdev_for_each_list(rdev, tmp, head) \
342 list_for_each_entry_safe(rdev, tmp, head, same_set)
345 * iterates through the 'same array disks' ringlist
347 #define rdev_for_each(rdev, tmp, mddev) \
348 list_for_each_entry_safe(rdev, tmp, &((mddev)->disks), same_set)
350 #define rdev_for_each_rcu(rdev, mddev) \
351 list_for_each_entry_rcu(rdev, &((mddev)->disks), same_set)
353 typedef struct mdk_thread_s {
354 void (*run) (mddev_t *mddev);
356 wait_queue_head_t wqueue;
358 struct task_struct *tsk;
359 unsigned long timeout;
362 #define THREAD_WAKEUP 0
364 #define __wait_event_lock_irq(wq, condition, lock, cmd) \
366 wait_queue_t __wait; \
367 init_waitqueue_entry(&__wait, current); \
369 add_wait_queue(&wq, &__wait); \
371 set_current_state(TASK_UNINTERRUPTIBLE); \
374 spin_unlock_irq(&lock); \
377 spin_lock_irq(&lock); \
379 current->state = TASK_RUNNING; \
380 remove_wait_queue(&wq, &__wait); \
383 #define wait_event_lock_irq(wq, condition, lock, cmd) \
387 __wait_event_lock_irq(wq, condition, lock, cmd); \
390 static inline void safe_put_page(struct page *p)
395 #endif /* CONFIG_BLOCK */
399 extern int register_md_personality(struct mdk_personality *p);
400 extern int unregister_md_personality(struct mdk_personality *p);
401 extern mdk_thread_t * md_register_thread(void (*run) (mddev_t *mddev),
402 mddev_t *mddev, const char *name);
403 extern void md_unregister_thread(mdk_thread_t *thread);
404 extern void md_wakeup_thread(mdk_thread_t *thread);
405 extern void md_check_recovery(mddev_t *mddev);
406 extern void md_write_start(mddev_t *mddev, struct bio *bi);
407 extern void md_write_end(mddev_t *mddev);
408 extern void md_done_sync(mddev_t *mddev, int blocks, int ok);
409 extern void md_error(mddev_t *mddev, mdk_rdev_t *rdev);
411 extern void md_super_write(mddev_t *mddev, mdk_rdev_t *rdev,
412 sector_t sector, int size, struct page *page);
413 extern void md_super_wait(mddev_t *mddev);
414 extern int sync_page_io(struct block_device *bdev, sector_t sector, int size,
415 struct page *page, int rw);
416 extern void md_do_sync(mddev_t *mddev);
417 extern void md_new_event(mddev_t *mddev);
418 extern int md_allow_write(mddev_t *mddev);
419 extern void md_wait_for_blocked_rdev(mdk_rdev_t *rdev, mddev_t *mddev);