Line data Source code
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 2 : typedef struct mddev_s mddev_t;
30 2 : typedef struct mdk_rdev_s mdk_rdev_t;
31 1 :
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 : struct block_device *bdev; /* block device handle */
44 :
45 : struct page *sb_page;
46 : int sb_loaded;
47 : __u64 sb_events;
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 */
52 :
53 : struct kobject kobj;
54 :
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
58 : * Working, but not
59 : * in sync with array
60 : * faulty==0 in_sync==0
61 : *
62 : * It can never have faulty==1, in_sync==1
63 : * This reduces the burden of testing multiple flags in many cases
64 : */
65 :
66 : unsigned long flags;
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
72 : * one array */
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;
81 :
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
87 : */
88 : sector_t recovery_offset;/* If this device has been partially
89 : * recovered, this is where we were
90 : * up to.
91 : */
92 :
93 : atomic_t nr_pending; /* number of pending requests.
94 : * only maintained for arrays that
95 : * support hot removal
96 : */
97 : atomic_t read_errors; /* number of consecutive read errors that
98 : * we have tried to ignore.
99 : */
100 : struct timespec last_read_error; /* monotonic time since our
101 : * last read error
102 : */
103 : atomic_t corrected_errors; /* number of corrected read errors,
104 : * for reporting to userspace and storing
105 : * in superblock.
106 : */
107 : struct work_struct del_work; /* used for delayed sysfs removal */
108 :
109 : struct sysfs_dirent *sysfs_state; /* handle for 'state'
110 : * sysfs entry */
111 5 : };
112 :
113 : struct mddev_s
114 : {
115 : void *private;
116 : struct mdk_personality *pers;
117 : dev_t unit;
118 : int md_minor;
119 : struct list_head disks;
120 : unsigned long flags;
121 : #define MD_CHANGE_DEVS 0 /* Some device status has changed */
122 : #define MD_CHANGE_CLEAN 1 /* transition to or from 'clean' */
123 : #define MD_CHANGE_PENDING 2 /* superblock update in progress */
124 :
125 : int suspended;
126 : atomic_t active_io;
127 : int ro;
128 :
129 : struct gendisk *gendisk;
130 :
131 : struct kobject kobj;
132 : int hold_active;
133 : #define UNTIL_IOCTL 1
134 : #define UNTIL_STOP 2
135 :
136 : /* Superblock information */
137 : int major_version,
138 : minor_version,
139 : patch_version;
140 : int persistent;
141 : int external; /* metadata is
142 : * managed externally */
143 : char metadata_type[17]; /* externally set*/
144 : int chunk_sectors;
145 : time_t ctime, utime;
146 : int level, layout;
147 : char clevel[16];
148 : int raid_disks;
149 : int max_disks;
150 : sector_t dev_sectors; /* used size of
151 : * component devices */
152 : sector_t array_sectors; /* exported array size */
153 : int external_size; /* size managed
154 : * externally */
155 : __u64 events;
156 :
157 : char uuid[16];
158 :
159 : /* If the array is being reshaped, we need to record the
160 : * new shape and an indication of where we are up to.
161 : * This is written to the superblock.
162 : * If reshape_position is MaxSector, then no reshape is happening (yet).
163 : */
164 : sector_t reshape_position;
165 : int delta_disks, new_level, new_layout;
166 : int new_chunk_sectors;
167 :
168 : struct mdk_thread_s *thread; /* management thread */
169 : struct mdk_thread_s *sync_thread; /* doing resync or reconstruct */
170 : sector_t curr_resync; /* last block scheduled */
171 : /* As resync requests can complete out of order, we cannot easily track
172 : * how much resync has been completed. So we occasionally pause until
173 : * everything completes, then set curr_resync_completed to curr_resync.
174 : * As such it may be well behind the real resync mark, but it is a value
175 : * we are certain of.
176 : */
177 : sector_t curr_resync_completed;
178 : unsigned long resync_mark; /* a recent timestamp */
179 : sector_t resync_mark_cnt;/* blocks written at resync_mark */
180 : sector_t curr_mark_cnt; /* blocks scheduled now */
181 :
182 : sector_t resync_max_sectors; /* may be set by personality */
183 :
184 : sector_t resync_mismatches; /* count of sectors where
185 : * parity/replica mismatch found
186 : */
187 :
188 : /* allow user-space to request suspension of IO to regions of the array */
189 : sector_t suspend_lo;
190 : sector_t suspend_hi;
191 : /* if zero, use the system-wide default */
192 : int sync_speed_min;
193 : int sync_speed_max;
194 :
195 : /* resync even though the same disks are shared among md-devices */
196 : int parallel_resync;
197 :
198 : int ok_start_degraded;
199 : /* recovery/resync flags
200 : * NEEDED: we might need to start a resync/recover
201 : * RUNNING: a thread is running, or about to be started
202 : * SYNC: actually doing a resync, not a recovery
203 : * RECOVER: doing recovery, or need to try it.
204 : * INTR: resync needs to be aborted for some reason
205 : * DONE: thread is done and is waiting to be reaped
206 : * REQUEST: user-space has requested a sync (used with SYNC)
207 : * CHECK: user-space request for check-only, no repair
208 : * RESHAPE: A reshape is happening
209 : *
210 : * If neither SYNC or RESHAPE are set, then it is a recovery.
211 : */
212 : #define MD_RECOVERY_RUNNING 0
213 : #define MD_RECOVERY_SYNC 1
214 : #define MD_RECOVERY_RECOVER 2
215 : #define MD_RECOVERY_INTR 3
216 : #define MD_RECOVERY_DONE 4
217 : #define MD_RECOVERY_NEEDED 5
218 : #define MD_RECOVERY_REQUESTED 6
219 : #define MD_RECOVERY_CHECK 7
220 : #define MD_RECOVERY_RESHAPE 8
221 : #define MD_RECOVERY_FROZEN 9
222 :
223 : unsigned long recovery;
224 : int recovery_disabled; /* if we detect that recovery
225 : * will always fail, set this
226 : * so we don't loop trying */
227 :
228 : int in_sync; /* know to not need resync */
229 : /* 'open_mutex' avoids races between 'md_open' and 'do_md_stop', so
230 : * that we are never stopping an array while it is open.
231 : * 'reconfig_mutex' protects all other reconfiguration.
232 : * These locks are separate due to conflicting interactions
233 : * with bdev->bd_mutex.
234 : * Lock ordering is:
235 : * reconfig_mutex -> bd_mutex : e.g. do_md_run -> revalidate_disk
236 : * bd_mutex -> open_mutex: e.g. __blkdev_get -> md_open
237 : */
238 : struct mutex open_mutex;
239 : struct mutex reconfig_mutex;
240 : atomic_t active; /* general refcount */
241 : atomic_t openers; /* number of active opens */
242 :
243 : int changed; /* true if we might need to reread partition info */
244 : int degraded; /* whether md should consider
245 : * adding a spare
246 : */
247 : int barriers_work; /* initialised to true, cleared as soon
248 : * as a barrier request to slave
249 : * fails. Only supported
250 : */
251 : struct bio *biolist; /* bios that need to be retried
252 : * because BIO_RW_BARRIER is not supported
253 : */
254 :
255 : atomic_t recovery_active; /* blocks scheduled, but not written */
256 : wait_queue_head_t recovery_wait;
257 : sector_t recovery_cp;
258 : sector_t resync_min; /* user requested sync
259 : * starts here */
260 : sector_t resync_max; /* resync should pause
261 : * when it gets here */
262 :
263 : struct sysfs_dirent *sysfs_state; /* handle for 'array_state'
264 : * file in sysfs.
265 : */
266 : struct sysfs_dirent *sysfs_action; /* handle for 'sync_action' */
267 :
268 : struct work_struct del_work; /* used for delayed sysfs removal */
269 :
270 : spinlock_t write_lock;
271 : wait_queue_head_t sb_wait; /* for waiting on superblock updates */
272 : atomic_t pending_writes; /* number of active superblock writes */
273 :
274 : unsigned int safemode; /* if set, update "clean" superblock
275 : * when no writes pending.
276 : */
277 : unsigned int safemode_delay;
278 : struct timer_list safemode_timer;
279 : atomic_t writes_pending;
280 : struct request_queue *queue; /* for plugging ... */
281 :
282 : atomic_t write_behind; /* outstanding async IO */
283 : unsigned int max_write_behind; /* 0 = sync */
284 :
285 : struct bitmap *bitmap; /* the bitmap for the device */
286 : struct {
287 : struct file *file; /* the bitmap file */
288 : loff_t offset; /* offset from superblock of
289 : * start of bitmap. May be
290 : * negative, but not '0'
291 : * For external metadata, offset
292 : * from start of device.
293 : */
294 : loff_t default_offset; /* this is the offset to use when
295 : * hot-adding a bitmap. It should
296 : * eventually be settable by sysfs.
297 : */
298 : struct mutex mutex;
299 : unsigned long chunksize;
300 : unsigned long daemon_sleep; /* how many seconds between updates? */
301 : unsigned long max_write_behind; /* write-behind mode */
302 : int external;
303 : } bitmap_info;
304 :
305 : atomic_t max_corr_read_errors; /* max read retries */
306 : struct list_head all_mddevs;
307 :
308 : struct attribute_group *to_remove;
309 : /* Generic barrier handling.
310 : * If there is a pending barrier request, all other
311 : * writes are blocked while the devices are flushed.
312 : * The last to finish a flush schedules a worker to
313 : * submit the barrier request (without the barrier flag),
314 : * then submit more flush requests.
315 : */
316 : struct bio *barrier;
317 : atomic_t flush_pending;
318 : struct work_struct barrier_work;
319 : };
320 :
321 :
322 : static inline void rdev_dec_pending(mdk_rdev_t *rdev, mddev_t *mddev)
323 : {
324 100 : int faulty = test_bit(Faulty, &rdev->flags);
325 175 : if (atomic_dec_and_test(&rdev->nr_pending) && faulty)
326 75 : set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
327 50 : }
328 :
329 : static inline void md_sync_acct(struct block_device *bdev, unsigned long nr_sectors)
330 : {
331 2 : atomic_add(nr_sectors, &bdev->bd_contains->bd_disk->sync_io);
332 1 : }
333 1 :
334 : struct mdk_personality
335 : {
336 : char *name;
337 : int level;
338 : struct list_head list;
339 : struct module *owner;
340 : int (*make_request)(struct request_queue *q, struct bio *bio);
341 : int (*run)(mddev_t *mddev);
342 : int (*stop)(mddev_t *mddev);
343 : void (*status)(struct seq_file *seq, mddev_t *mddev);
344 : /* error_handler must set ->faulty and clear ->in_sync
345 : * if appropriate, and should abort recovery if needed
346 : */
347 : void (*error_handler)(mddev_t *mddev, mdk_rdev_t *rdev);
348 : int (*hot_add_disk) (mddev_t *mddev, mdk_rdev_t *rdev);
349 : int (*hot_remove_disk) (mddev_t *mddev, int number);
350 : int (*spare_active) (mddev_t *mddev);
351 : sector_t (*sync_request)(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster);
352 : int (*resize) (mddev_t *mddev, sector_t sectors);
353 : sector_t (*size) (mddev_t *mddev, sector_t sectors, int raid_disks);
354 : int (*check_reshape) (mddev_t *mddev);
355 : int (*start_reshape) (mddev_t *mddev);
356 : void (*finish_reshape) (mddev_t *mddev);
357 : /* quiesce moves between quiescence states
358 : * 0 - fully active
359 : * 1 - no new requests allowed
360 : * others - reserved
361 : */
362 : void (*quiesce) (mddev_t *mddev, int state);
363 : /* takeover is used to transition an array from one
364 : * personality to another. The new personality must be able
365 : * to handle the data in the current layout.
366 : * e.g. 2drive raid1 -> 2drive raid5
367 : * ndrive raid5 -> degraded n+1drive raid6 with special layout
368 : * If the takeover succeeds, a new 'private' structure is returned.
369 : * This needs to be installed and then ->run used to activate the
370 : * array.
371 : */
372 : void *(*takeover) (mddev_t *mddev);
373 : };
374 :
375 :
376 : struct md_sysfs_entry {
377 : struct attribute attr;
378 : ssize_t (*show)(mddev_t *, char *);
379 : ssize_t (*store)(mddev_t *, const char *, size_t);
380 : };
381 : extern struct attribute_group md_bitmap_group;
382 :
383 : static inline char * mdname (mddev_t * mddev)
384 : {
385 77 : return mddev->gendisk ? mddev->gendisk->disk_name : "mdX";
386 : }
387 1 :
388 : /*
389 : * iterates through some rdev ringlist. It's safe to remove the
390 : * current 'rdev'. Dont touch 'tmp' though.
391 : */
392 : #define rdev_for_each_list(rdev, tmp, head) \
393 : list_for_each_entry_safe(rdev, tmp, head, same_set)
394 :
395 : /*
396 : * iterates through the 'same array disks' ringlist
397 : */
398 : #define rdev_for_each(rdev, tmp, mddev) \
399 : list_for_each_entry_safe(rdev, tmp, &((mddev)->disks), same_set)
400 :
401 : #define rdev_for_each_rcu(rdev, mddev) \
402 : list_for_each_entry_rcu(rdev, &((mddev)->disks), same_set)
403 :
404 : typedef struct mdk_thread_s {
405 : void (*run) (mddev_t *mddev);
406 : mddev_t *mddev;
407 : wait_queue_head_t wqueue;
408 : unsigned long flags;
409 : struct task_struct *tsk;
410 : unsigned long timeout;
411 1 : } mdk_thread_t;
412 :
413 : #define THREAD_WAKEUP 0
414 :
415 : #define __wait_event_lock_irq(wq, condition, lock, cmd) \
416 : do { \
417 : wait_queue_t __wait; \
418 : init_waitqueue_entry(&__wait, current); \
419 : \
420 : add_wait_queue(&wq, &__wait); \
421 : for (;;) { \
422 : set_current_state(TASK_UNINTERRUPTIBLE); \
423 : if (condition) \
424 : break; \
425 : spin_unlock_irq(&lock); \
426 : cmd; \
427 : schedule(); \
428 : spin_lock_irq(&lock); \
429 : } \
430 : current->state = TASK_RUNNING; \
431 : remove_wait_queue(&wq, &__wait); \
432 : } while (0)
433 :
434 : #define wait_event_lock_irq(wq, condition, lock, cmd) \
435 : do { \
436 : if (condition) \
437 : break; \
438 : __wait_event_lock_irq(wq, condition, lock, cmd); \
439 : } while (0)
440 :
441 : static inline void safe_put_page(struct page *p)
442 : {
443 36 : if (p) put_page(p);
444 12 : }
445 :
446 : extern int register_md_personality(struct mdk_personality *p);
447 : extern int unregister_md_personality(struct mdk_personality *p);
448 : extern mdk_thread_t * md_register_thread(void (*run) (mddev_t *mddev),
449 : mddev_t *mddev, const char *name);
450 : extern void md_unregister_thread(mdk_thread_t *thread);
451 : extern void md_wakeup_thread(mdk_thread_t *thread);
452 : extern void md_check_recovery(mddev_t *mddev);
453 : extern void md_write_start(mddev_t *mddev, struct bio *bi);
454 : extern void md_write_end(mddev_t *mddev);
455 : extern void md_done_sync(mddev_t *mddev, int blocks, int ok);
456 : extern void md_error(mddev_t *mddev, mdk_rdev_t *rdev);
457 :
458 : extern int mddev_congested(mddev_t *mddev, int bits);
459 : extern void md_barrier_request(mddev_t *mddev, struct bio *bio);
460 : extern void md_super_write(mddev_t *mddev, mdk_rdev_t *rdev,
461 : sector_t sector, int size, struct page *page);
462 : extern void md_super_wait(mddev_t *mddev);
463 : extern int sync_page_io(struct block_device *bdev, sector_t sector, int size,
464 : struct page *page, int rw);
465 : extern void md_do_sync(mddev_t *mddev);
466 : extern void md_new_event(mddev_t *mddev);
467 : extern int md_allow_write(mddev_t *mddev);
468 : extern void md_wait_for_blocked_rdev(mdk_rdev_t *rdev, mddev_t *mddev);
469 : extern void md_set_array_sectors(mddev_t *mddev, sector_t array_sectors);
470 : extern int md_check_no_bitmap(mddev_t *mddev);
471 : extern int md_integrity_register(mddev_t *mddev);
472 : extern void md_integrity_add_rdev(mdk_rdev_t *rdev, mddev_t *mddev);
473 : extern int strict_strtoul_scaled(const char *cp, unsigned long *res, int scale);
474 : extern void restore_bitmap_write_access(struct file *file);
475 :
476 : #endif /* _MD_MD_H */
|