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