1 /*
2 md_k.h : kernel internal structure of the Linux MD driver
3 Copyright (C) 1996-98 Ingo Molnar, Gadi Oxman
4
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)
8 any later version.
9
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.
13 */
14
15 #ifndef _MD_MD_H
16 #define _MD_MD_H
17
18 #include <linux/blkdev.h>
19 #include <linux/kobject.h>
20 #include <linux/list.h>
21 #include <linux/mm.h>
22 #include <linux/mutex.h>
23 #include <linux/timer.h>
24 #include <linux/wait.h>
25 #include <linux/workqueue.h>
26
27 #define MaxSector (~(sector_t)0)
28
29 typedef struct mddev_s mddev_t;
30 typedef struct mdk_rdev_s mdk_rdev_t;
31
32 /*
33 * MD's 'extended' device
34 */
35 struct mdk_rdev_s
36 {
37 struct list_head same_set; /* RAID devices within the same set */
38
39 sector_t sectors; /* Device size (in 512bytes sectors) */
40 mddev_t *mddev; /* RAID array if running */
41 int last_events; /* IO event timestamp */
42
43 /*
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).
47 */
48 struct block_device *meta_bdev;
49 struct block_device *bdev; /* block device handle */
50
51 struct page *sb_page;
52 int sb_loaded;
53 __u64 sb_events;
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 */
58
59 struct kobject kobj;
60
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
64 * Working, but not
65 * in sync with array
66 * faulty==0 in_sync==0
67 *
68 * It can never have faulty==1, in_sync==1
69 * This reduces the burden of testing multiple flags in many cases
70 */
71
72 unsigned long flags;
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;
81
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.
86 */
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
90 */
91 sector_t recovery_offset;/* If this device has been partially
92 * recovered, this is where we were
93 * up to.
94 */
95
96 atomic_t nr_pending; /* number of pending requests.
97 * only maintained for arrays that
98 * support hot removal
99 */
100 atomic_t read_errors; /* number of consecutive read errors that
101 * we have tried to ignore.
102 */
103 struct timespec last_read_error; /* monotonic time since our
104 * last read error
105 */
106 atomic_t corrected_errors; /* number of corrected read errors,
107 * for reporting to userspace and storing
108 * in superblock.
109 */
110 struct work_struct del_work; /* used for delayed sysfs removal */
111
112 struct sysfs_dirent *sysfs_state; /* handle for 'state'
113 * sysfs entry */
114 };
115
116 struct mddev_s
117 {
118 void *private;
119 struct mdk_personality *pers;
120 dev_t unit;
121 int md_minor;
122 struct list_head disks;
123 unsigned long flags;
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
128 int suspended;
129 atomic_t active_io;
130 int ro;
131 int sysfs_active; /* set when sysfs deletes
132 * are happening, so run/
133 * takeover/stop are not safe
134 */
135 int ready; /* See when safe to pass
136 * IO requests down */
137 struct gendisk *gendisk;
138
139 struct kobject kobj;
140 int hold_active;
141 #define UNTIL_IOCTL 1
142 #define UNTIL_STOP 2
143
144 /* Superblock information */
145 int major_version,
146 minor_version,
147 patch_version;
148 int persistent;
149 int external; /* metadata is
150 * managed externally */
151 char metadata_type[17]; /* externally set*/
152 int chunk_sectors;
153 time_t ctime, utime;
154 int level, layout;
155 char clevel[16];
156 int raid_disks;
157 int max_disks;
158 sector_t dev_sectors; /* used size of
159 * component devices */
160 sector_t array_sectors; /* exported array size */
161 int external_size; /* size managed
162 * externally */
163 __u64 events;
164 /* If the last 'event' was simply a clean->dirty transition, and
165 * we didn't write it to the spares, then it is safe and simple
166 * to just decrement the event count on a dirty->clean transition.
167 * So we record that possibility here.
168 */
169 int can_decrease_events;
170
171 char uuid[16];
172
173 /* If the array is being reshaped, we need to record the
174 * new shape and an indication of where we are up to.
175 * This is written to the superblock.
176 * If reshape_position is MaxSector, then no reshape is happening (yet).
177 */
178 sector_t reshape_position;
179 int delta_disks, new_level, new_layout;
180 int new_chunk_sectors;
181
182 atomic_t plug_cnt; /* If device is expecting
183 * more bios soon.
184 */
185 struct mdk_thread_s *thread; /* management thread */
186 struct mdk_thread_s *sync_thread; /* doing resync or reconstruct */
187 sector_t curr_resync; /* last block scheduled */
188 /* As resync requests can complete out of order, we cannot easily track
189 * how much resync has been completed. So we occasionally pause until
190 * everything completes, then set curr_resync_completed to curr_resync.
191 * As such it may be well behind the real resync mark, but it is a value
192 * we are certain of.
193 */
194 sector_t curr_resync_completed;
195 unsigned long resync_mark; /* a recent timestamp */
196 sector_t resync_mark_cnt;/* blocks written at resync_mark */
197 sector_t curr_mark_cnt; /* blocks scheduled now */
198
199 sector_t resync_max_sectors; /* may be set by personality */
200
201 sector_t resync_mismatches; /* count of sectors where
202 * parity/replica mismatch found
203 */
204
205 /* allow user-space to request suspension of IO to regions of the array */
206 sector_t suspend_lo;
207 sector_t suspend_hi;
208 /* if zero, use the system-wide default */
209 int sync_speed_min;
210 int sync_speed_max;
211
212 /* resync even though the same disks are shared among md-devices */
213 int parallel_resync;
214
215 int ok_start_degraded;
216 /* recovery/resync flags
217 * NEEDED: we might need to start a resync/recover
218 * RUNNING: a thread is running, or about to be started
219 * SYNC: actually doing a resync, not a recovery
220 * RECOVER: doing recovery, or need to try it.
221 * INTR: resync needs to be aborted for some reason
222 * DONE: thread is done and is waiting to be reaped
223 * REQUEST: user-space has requested a sync (used with SYNC)
224 * CHECK: user-space request for check-only, no repair
225 * RESHAPE: A reshape is happening
226 *
227 * If neither SYNC or RESHAPE are set, then it is a recovery.
228 */
229 #define MD_RECOVERY_RUNNING 0
230 #define MD_RECOVERY_SYNC 1
231 #define MD_RECOVERY_RECOVER 2
232 #define MD_RECOVERY_INTR 3
233 #define MD_RECOVERY_DONE 4
234 #define MD_RECOVERY_NEEDED 5
235 #define MD_RECOVERY_REQUESTED 6
236 #define MD_RECOVERY_CHECK 7
237 #define MD_RECOVERY_RESHAPE 8
238 #define MD_RECOVERY_FROZEN 9
239
240 unsigned long recovery;
241 int recovery_disabled; /* if we detect that recovery
242 * will always fail, set this
243 * so we don't loop trying */
244
245 int in_sync; /* know to not need resync */
246 /* 'open_mutex' avoids races between 'md_open' and 'do_md_stop', so
247 * that we are never stopping an array while it is open.
248 * 'reconfig_mutex' protects all other reconfiguration.
249 * These locks are separate due to conflicting interactions
250 * with bdev->bd_mutex.
251 * Lock ordering is:
252 * reconfig_mutex -> bd_mutex : e.g. do_md_run -> revalidate_disk
253 * bd_mutex -> open_mutex: e.g. __blkdev_get -> md_open
254 */
255 struct mutex open_mutex;
256 struct mutex reconfig_mutex;
257 atomic_t active; /* general refcount */
258 atomic_t openers; /* number of active opens */
259
260 int changed; /* True if we might need to
261 * reread partition info */
262 int degraded; /* whether md should consider
263 * adding a spare
264 */
265
266 atomic_t recovery_active; /* blocks scheduled, but not written */
267 wait_queue_head_t recovery_wait;
268 sector_t recovery_cp;
269 sector_t resync_min; /* user requested sync
270 * starts here */
271 sector_t resync_max; /* resync should pause
272 * when it gets here */
273
274 struct sysfs_dirent *sysfs_state; /* handle for 'array_state'
275 * file in sysfs.
276 */
277 struct sysfs_dirent *sysfs_action; /* handle for 'sync_action' */
278
279 struct work_struct del_work; /* used for delayed sysfs removal */
280
281 spinlock_t write_lock;
282 wait_queue_head_t sb_wait; /* for waiting on superblock updates */
283 atomic_t pending_writes; /* number of active superblock writes */
284
285 unsigned int safemode; /* if set, update "clean" superblock
286 * when no writes pending.
287 */
288 unsigned int safemode_delay;
289 struct timer_list safemode_timer;
290 atomic_t writes_pending;
291 struct request_queue *queue; /* for plugging ... */
292
293 struct bitmap *bitmap; /* the bitmap for the device */
294 struct {
295 struct file *file; /* the bitmap file */
296 loff_t offset; /* offset from superblock of
297 * start of bitmap. May be
298 * negative, but not '0'
299 * For external metadata, offset
300 * from start of device.
301 */
302 loff_t default_offset; /* this is the offset to use when
303 * hot-adding a bitmap. It should
304 * eventually be settable by sysfs.
305 */
306 /* When md is serving under dm, it might use a
307 * dirty_log to store the bits.
308 */
309 struct dm_dirty_log *log;
310
311 struct mutex mutex;
312 unsigned long chunksize;
313 unsigned long daemon_sleep; /* how many jiffies between updates? */
314 unsigned long max_write_behind; /* write-behind mode */
315 int external;
316 } bitmap_info;
317
318 atomic_t max_corr_read_errors; /* max read retries */
319 struct list_head all_mddevs;
320
321 struct attribute_group *to_remove;
322
323 struct bio_set *bio_set;
324
325 /* Generic flush handling.
326 * The last to finish preflush schedules a worker to submit
327 * the rest of the request (without the REQ_FLUSH flag).
328 */
329 struct bio *flush_bio;
330 atomic_t flush_pending;
331 struct work_struct flush_work;
332 struct work_struct event_work; /* used by dm to report failure event */
333 };
334
335
rdev_dec_pending(mdk_rdev_t * rdev,mddev_t * mddev)336 static inline void rdev_dec_pending(mdk_rdev_t *rdev, mddev_t *mddev)
337 {
338 int faulty = test_bit(Faulty, &rdev->flags);
339 if (atomic_dec_and_test(&rdev->nr_pending) && faulty)
340 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
341 }
342
md_sync_acct(struct block_device * bdev,unsigned long nr_sectors)343 static inline void md_sync_acct(struct block_device *bdev, unsigned long nr_sectors)
344 {
345 atomic_add(nr_sectors, &bdev->bd_contains->bd_disk->sync_io);
346 }
347
348 struct mdk_personality
349 {
350 char *name;
351 int level;
352 struct list_head list;
353 struct module *owner;
354 int (*make_request)(mddev_t *mddev, struct bio *bio);
355 int (*run)(mddev_t *mddev);
356 int (*stop)(mddev_t *mddev);
357 void (*status)(struct seq_file *seq, mddev_t *mddev);
358 /* error_handler must set ->faulty and clear ->in_sync
359 * if appropriate, and should abort recovery if needed
360 */
361 void (*error_handler)(mddev_t *mddev, mdk_rdev_t *rdev);
362 int (*hot_add_disk) (mddev_t *mddev, mdk_rdev_t *rdev);
363 int (*hot_remove_disk) (mddev_t *mddev, int number);
364 int (*spare_active) (mddev_t *mddev);
365 sector_t (*sync_request)(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster);
366 int (*resize) (mddev_t *mddev, sector_t sectors);
367 sector_t (*size) (mddev_t *mddev, sector_t sectors, int raid_disks);
368 int (*check_reshape) (mddev_t *mddev);
369 int (*start_reshape) (mddev_t *mddev);
370 void (*finish_reshape) (mddev_t *mddev);
371 /* quiesce moves between quiescence states
372 * 0 - fully active
373 * 1 - no new requests allowed
374 * others - reserved
375 */
376 void (*quiesce) (mddev_t *mddev, int state);
377 /* takeover is used to transition an array from one
378 * personality to another. The new personality must be able
379 * to handle the data in the current layout.
380 * e.g. 2drive raid1 -> 2drive raid5
381 * ndrive raid5 -> degraded n+1drive raid6 with special layout
382 * If the takeover succeeds, a new 'private' structure is returned.
383 * This needs to be installed and then ->run used to activate the
384 * array.
385 */
386 void *(*takeover) (mddev_t *mddev);
387 };
388
389
390 struct md_sysfs_entry {
391 struct attribute attr;
392 ssize_t (*show)(mddev_t *, char *);
393 ssize_t (*store)(mddev_t *, const char *, size_t);
394 };
395 extern struct attribute_group md_bitmap_group;
396
sysfs_get_dirent_safe(struct sysfs_dirent * sd,char * name)397 static inline struct sysfs_dirent *sysfs_get_dirent_safe(struct sysfs_dirent *sd, char *name)
398 {
399 if (sd)
400 return sysfs_get_dirent(sd, NULL, name);
401 return sd;
402 }
sysfs_notify_dirent_safe(struct sysfs_dirent * sd)403 static inline void sysfs_notify_dirent_safe(struct sysfs_dirent *sd)
404 {
405 if (sd)
406 sysfs_notify_dirent(sd);
407 }
408
mdname(mddev_t * mddev)409 static inline char * mdname (mddev_t * mddev)
410 {
411 return mddev->gendisk ? mddev->gendisk->disk_name : "mdX";
412 }
413
414 /*
415 * iterates through some rdev ringlist. It's safe to remove the
416 * current 'rdev'. Dont touch 'tmp' though.
417 */
418 #define rdev_for_each_list(rdev, tmp, head) \
419 list_for_each_entry_safe(rdev, tmp, head, same_set)
420
421 /*
422 * iterates through the 'same array disks' ringlist
423 */
424 #define rdev_for_each(rdev, tmp, mddev) \
425 list_for_each_entry_safe(rdev, tmp, &((mddev)->disks), same_set)
426
427 #define rdev_for_each_rcu(rdev, mddev) \
428 list_for_each_entry_rcu(rdev, &((mddev)->disks), same_set)
429
430 typedef struct mdk_thread_s {
431 void (*run) (mddev_t *mddev);
432 mddev_t *mddev;
433 wait_queue_head_t wqueue;
434 unsigned long flags;
435 struct task_struct *tsk;
436 unsigned long timeout;
437 } mdk_thread_t;
438
439 #define THREAD_WAKEUP 0
440
441 #define __wait_event_lock_irq(wq, condition, lock, cmd) \
442 do { \
443 wait_queue_t __wait; \
444 init_waitqueue_entry(&__wait, current); \
445 \
446 add_wait_queue(&wq, &__wait); \
447 for (;;) { \
448 set_current_state(TASK_UNINTERRUPTIBLE); \
449 if (condition) \
450 break; \
451 spin_unlock_irq(&lock); \
452 cmd; \
453 schedule(); \
454 spin_lock_irq(&lock); \
455 } \
456 current->state = TASK_RUNNING; \
457 remove_wait_queue(&wq, &__wait); \
458 } while (0)
459
460 #define wait_event_lock_irq(wq, condition, lock, cmd) \
461 do { \
462 if (condition) \
463 break; \
464 __wait_event_lock_irq(wq, condition, lock, cmd); \
465 } while (0)
466
safe_put_page(struct page * p)467 static inline void safe_put_page(struct page *p)
468 {
469 if (p) put_page(p);
470 }
471
472 extern int register_md_personality(struct mdk_personality *p);
473 extern int unregister_md_personality(struct mdk_personality *p);
474 extern mdk_thread_t * md_register_thread(void (*run) (mddev_t *mddev),
475 mddev_t *mddev, const char *name);
476 extern void md_unregister_thread(mdk_thread_t *thread);
477 extern void md_wakeup_thread(mdk_thread_t *thread);
478 extern void md_check_recovery(mddev_t *mddev);
479 extern void md_write_start(mddev_t *mddev, struct bio *bi);
480 extern void md_write_end(mddev_t *mddev);
481 extern void md_done_sync(mddev_t *mddev, int blocks, int ok);
482 extern void md_error(mddev_t *mddev, mdk_rdev_t *rdev);
483
484 extern int mddev_congested(mddev_t *mddev, int bits);
485 extern void md_flush_request(mddev_t *mddev, struct bio *bio);
486 extern void md_super_write(mddev_t *mddev, mdk_rdev_t *rdev,
487 sector_t sector, int size, struct page *page);
488 extern void md_super_wait(mddev_t *mddev);
489 extern int sync_page_io(mdk_rdev_t *rdev, sector_t sector, int size,
490 struct page *page, int rw, bool metadata_op);
491 extern void md_do_sync(mddev_t *mddev);
492 extern void md_new_event(mddev_t *mddev);
493 extern int md_allow_write(mddev_t *mddev);
494 extern void md_wait_for_blocked_rdev(mdk_rdev_t *rdev, mddev_t *mddev);
495 extern void md_set_array_sectors(mddev_t *mddev, sector_t array_sectors);
496 extern int md_check_no_bitmap(mddev_t *mddev);
497 extern int md_integrity_register(mddev_t *mddev);
498 extern void md_integrity_add_rdev(mdk_rdev_t *rdev, mddev_t *mddev);
499 extern int strict_strtoul_scaled(const char *cp, unsigned long *res, int scale);
500 extern void restore_bitmap_write_access(struct file *file);
501
502 extern void mddev_init(mddev_t *mddev);
503 extern int md_run(mddev_t *mddev);
504 extern void md_stop(mddev_t *mddev);
505 extern void md_stop_writes(mddev_t *mddev);
506 extern void md_rdev_init(mdk_rdev_t *rdev);
507
508 extern void mddev_suspend(mddev_t *mddev);
509 extern void mddev_resume(mddev_t *mddev);
510 extern struct bio *bio_clone_mddev(struct bio *bio, gfp_t gfp_mask,
511 mddev_t *mddev);
512 extern struct bio *bio_alloc_mddev(gfp_t gfp_mask, int nr_iovecs,
513 mddev_t *mddev);
514 extern int mddev_check_plugged(mddev_t *mddev);
515 #endif /* _MD_MD_H */
516