/drivers/md/md.h
C Header | 475 lines | 274 code | 57 blank | 144 comment | 8 complexity | 6e92af891ddeaf091884eb81bfa1474d MD5 | raw file
Possible License(s): CC-BY-SA-3.0, GPL-2.0, LGPL-2.0, AGPL-1.0
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
29typedef struct mddev_s mddev_t;
30typedef struct mdk_rdev_s mdk_rdev_t;
31
32/*
33 * MD's 'extended' device
34 */
35struct 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};
112
113struct 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 /* Generic barrier handling.
309 * If there is a pending barrier request, all other
310 * writes are blocked while the devices are flushed.
311 * The last to finish a flush schedules a worker to
312 * submit the barrier request (without the barrier flag),
313 * then submit more flush requests.
314 */
315 struct bio *barrier;
316 atomic_t flush_pending;
317 struct work_struct barrier_work;
318};
319
320
321static inline void rdev_dec_pending(mdk_rdev_t *rdev, mddev_t *mddev)
322{
323 int faulty = test_bit(Faulty, &rdev->flags);
324 if (atomic_dec_and_test(&rdev->nr_pending) && faulty)
325 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
326}
327
328static inline void md_sync_acct(struct block_device *bdev, unsigned long nr_sectors)
329{
330 atomic_add(nr_sectors, &bdev->bd_contains->bd_disk->sync_io);
331}
332
333struct mdk_personality
334{
335 char *name;
336 int level;
337 struct list_head list;
338 struct module *owner;
339 int (*make_request)(struct request_queue *q, struct bio *bio);
340 int (*run)(mddev_t *mddev);
341 int (*stop)(mddev_t *mddev);
342 void (*status)(struct seq_file *seq, mddev_t *mddev);
343 /* error_handler must set ->faulty and clear ->in_sync
344 * if appropriate, and should abort recovery if needed
345 */
346 void (*error_handler)(mddev_t *mddev, mdk_rdev_t *rdev);
347 int (*hot_add_disk) (mddev_t *mddev, mdk_rdev_t *rdev);
348 int (*hot_remove_disk) (mddev_t *mddev, int number);
349 int (*spare_active) (mddev_t *mddev);
350 sector_t (*sync_request)(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster);
351 int (*resize) (mddev_t *mddev, sector_t sectors);
352 sector_t (*size) (mddev_t *mddev, sector_t sectors, int raid_disks);
353 int (*check_reshape) (mddev_t *mddev);
354 int (*start_reshape) (mddev_t *mddev);
355 void (*finish_reshape) (mddev_t *mddev);
356 /* quiesce moves between quiescence states
357 * 0 - fully active
358 * 1 - no new requests allowed
359 * others - reserved
360 */
361 void (*quiesce) (mddev_t *mddev, int state);
362 /* takeover is used to transition an array from one
363 * personality to another. The new personality must be able
364 * to handle the data in the current layout.
365 * e.g. 2drive raid1 -> 2drive raid5
366 * ndrive raid5 -> degraded n+1drive raid6 with special layout
367 * If the takeover succeeds, a new 'private' structure is returned.
368 * This needs to be installed and then ->run used to activate the
369 * array.
370 */
371 void *(*takeover) (mddev_t *mddev);
372};
373
374
375struct md_sysfs_entry {
376 struct attribute attr;
377 ssize_t (*show)(mddev_t *, char *);
378 ssize_t (*store)(mddev_t *, const char *, size_t);
379};
380extern struct attribute_group md_bitmap_group;
381
382static inline char * mdname (mddev_t * mddev)
383{
384 return mddev->gendisk ? mddev->gendisk->disk_name : "mdX";
385}
386
387/*
388 * iterates through some rdev ringlist. It's safe to remove the
389 * current 'rdev'. Dont touch 'tmp' though.
390 */
391#define rdev_for_each_list(rdev, tmp, head) \
392 list_for_each_entry_safe(rdev, tmp, head, same_set)
393
394/*
395 * iterates through the 'same array disks' ringlist
396 */
397#define rdev_for_each(rdev, tmp, mddev) \
398 list_for_each_entry_safe(rdev, tmp, &((mddev)->disks), same_set)
399
400#define rdev_for_each_rcu(rdev, mddev) \
401 list_for_each_entry_rcu(rdev, &((mddev)->disks), same_set)
402
403typedef struct mdk_thread_s {
404 void (*run) (mddev_t *mddev);
405 mddev_t *mddev;
406 wait_queue_head_t wqueue;
407 unsigned long flags;
408 struct task_struct *tsk;
409 unsigned long timeout;
410} mdk_thread_t;
411
412#define THREAD_WAKEUP 0
413
414#define __wait_event_lock_irq(wq, condition, lock, cmd) \
415do { \
416 wait_queue_t __wait; \
417 init_waitqueue_entry(&__wait, current); \
418 \
419 add_wait_queue(&wq, &__wait); \
420 for (;;) { \
421 set_current_state(TASK_UNINTERRUPTIBLE); \
422 if (condition) \
423 break; \
424 spin_unlock_irq(&lock); \
425 cmd; \
426 schedule(); \
427 spin_lock_irq(&lock); \
428 } \
429 current->state = TASK_RUNNING; \
430 remove_wait_queue(&wq, &__wait); \
431} while (0)
432
433#define wait_event_lock_irq(wq, condition, lock, cmd) \
434do { \
435 if (condition) \
436 break; \
437 __wait_event_lock_irq(wq, condition, lock, cmd); \
438} while (0)
439
440static inline void safe_put_page(struct page *p)
441{
442 if (p) put_page(p);
443}
444
445extern int register_md_personality(struct mdk_personality *p);
446extern int unregister_md_personality(struct mdk_personality *p);
447extern mdk_thread_t * md_register_thread(void (*run) (mddev_t *mddev),
448 mddev_t *mddev, const char *name);
449extern void md_unregister_thread(mdk_thread_t *thread);
450extern void md_wakeup_thread(mdk_thread_t *thread);
451extern void md_check_recovery(mddev_t *mddev);
452extern void md_write_start(mddev_t *mddev, struct bio *bi);
453extern void md_write_end(mddev_t *mddev);
454extern void md_done_sync(mddev_t *mddev, int blocks, int ok);
455extern void md_error(mddev_t *mddev, mdk_rdev_t *rdev);
456
457extern int mddev_congested(mddev_t *mddev, int bits);
458extern void md_barrier_request(mddev_t *mddev, struct bio *bio);
459extern void md_super_write(mddev_t *mddev, mdk_rdev_t *rdev,
460 sector_t sector, int size, struct page *page);
461extern void md_super_wait(mddev_t *mddev);
462extern int sync_page_io(struct block_device *bdev, sector_t sector, int size,
463 struct page *page, int rw);
464extern void md_do_sync(mddev_t *mddev);
465extern void md_new_event(mddev_t *mddev);
466extern int md_allow_write(mddev_t *mddev);
467extern void md_wait_for_blocked_rdev(mdk_rdev_t *rdev, mddev_t *mddev);
468extern void md_set_array_sectors(mddev_t *mddev, sector_t array_sectors);
469extern int md_check_no_bitmap(mddev_t *mddev);
470extern int md_integrity_register(mddev_t *mddev);
471extern void md_integrity_add_rdev(mdk_rdev_t *rdev, mddev_t *mddev);
472extern int strict_strtoul_scaled(const char *cp, unsigned long *res, int scale);
473extern void restore_bitmap_write_access(struct file *file);
474
475#endif /* _MD_MD_H */