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Linux v2.6.15-rc6
[pohmelfs.git] / include / linux / raid / md_k.h
blob46629a275ba9bb06f9d270c187da6a00f8805815
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_K_H
16 #define _MD_K_H
17
18 /* and dm-bio-list.h is not under include/linux because.... ??? */
19 #include "../../../drivers/md/dm-bio-list.h"
20
21 #define MD_RESERVED 0UL
22 #define LINEAR 1UL
23 #define RAID0 2UL
24 #define RAID1 3UL
25 #define RAID5 4UL
26 #define TRANSLUCENT 5UL
27 #define HSM 6UL
28 #define MULTIPATH 7UL
29 #define RAID6 8UL
30 #define RAID10 9UL
31 #define FAULTY 10UL
32 #define MAX_PERSONALITY 11UL
33
34 #define LEVEL_MULTIPATH (-4)
35 #define LEVEL_LINEAR (-1)
36 #define LEVEL_FAULTY (-5)
37
38 #define MaxSector (~(sector_t)0)
39 #define MD_THREAD_NAME_MAX 14
40
41 static inline int pers_to_level (int pers)
42 {
43 switch (pers) {
44 case FAULTY: return LEVEL_FAULTY;
45 case MULTIPATH: return LEVEL_MULTIPATH;
46 case HSM: return -3;
47 case TRANSLUCENT: return -2;
48 case LINEAR: return LEVEL_LINEAR;
49 case RAID0: return 0;
50 case RAID1: return 1;
51 case RAID5: return 5;
52 case RAID6: return 6;
53 case RAID10: return 10;
54 }
55 BUG();
56 return MD_RESERVED;
57 }
58
59 static inline int level_to_pers (int level)
60 {
61 switch (level) {
62 case LEVEL_FAULTY: return FAULTY;
63 case LEVEL_MULTIPATH: return MULTIPATH;
64 case -3: return HSM;
65 case -2: return TRANSLUCENT;
66 case LEVEL_LINEAR: return LINEAR;
67 case 0: return RAID0;
68 case 1: return RAID1;
69 case 4:
70 case 5: return RAID5;
71 case 6: return RAID6;
72 case 10: return RAID10;
73 }
74 return MD_RESERVED;
75 }
76
77 typedef struct mddev_s mddev_t;
78 typedef struct mdk_rdev_s mdk_rdev_t;
79
80 #define MAX_MD_DEVS 256 /* Max number of md dev */
81
82 /*
83 * options passed in raidrun:
84 */
85
86 #define MAX_CHUNK_SIZE (4096*1024)
87
88 /*
89 * MD's 'extended' device
90 */
91 struct mdk_rdev_s
92 {
93 struct list_head same_set; /* RAID devices within the same set */
94
95 sector_t size; /* Device size (in blocks) */
96 mddev_t *mddev; /* RAID array if running */
97 unsigned long last_events; /* IO event timestamp */
98
99 struct block_device *bdev; /* block device handle */
100
101 struct page *sb_page;
102 int sb_loaded;
103 sector_t data_offset; /* start of data in array */
104 sector_t sb_offset;
105 int sb_size; /* bytes in the superblock */
106 int preferred_minor; /* autorun support */
107
108 struct kobject kobj;
109
110 /* A device can be in one of three states based on two flags:
111 * Not working: faulty==1 in_sync==0
112 * Fully working: faulty==0 in_sync==1
113 * Working, but not
114 * in sync with array
115 * faulty==0 in_sync==0
116 *
117 * It can never have faulty==1, in_sync==1
118 * This reduces the burden of testing multiple flags in many cases
119 */
120
121 unsigned long flags;
122 #define Faulty 1 /* device is known to have a fault */
123 #define In_sync 2 /* device is in_sync with rest of array */
124 #define WriteMostly 4 /* Avoid reading if at all possible */
125 #define BarriersNotsupp 5 /* BIO_RW_BARRIER is not supported */
126
127 int desc_nr; /* descriptor index in the superblock */
128 int raid_disk; /* role of device in array */
129 int saved_raid_disk; /* role that device used to have in the
130 * array and could again if we did a partial
131 * resync from the bitmap
132 */
133
134 atomic_t nr_pending; /* number of pending requests.
135 * only maintained for arrays that
136 * support hot removal
137 */
138 atomic_t read_errors; /* number of consecutive read errors that
139 * we have tried to ignore.
140 */
141 };
142
143 typedef struct mdk_personality_s mdk_personality_t;
144
145 struct mddev_s
146 {
147 void *private;
148 mdk_personality_t *pers;
149 dev_t unit;
150 int md_minor;
151 struct list_head disks;
152 int sb_dirty;
153 int ro;
154
155 struct gendisk *gendisk;
156
157 struct kobject kobj;
158
159 /* Superblock information */
160 int major_version,
161 minor_version,
162 patch_version;
163 int persistent;
164 int chunk_size;
165 time_t ctime, utime;
166 int level, layout;
167 int raid_disks;
168 int max_disks;
169 sector_t size; /* used size of component devices */
170 sector_t array_size; /* exported array size */
171 __u64 events;
172
173 char uuid[16];
174
175 struct mdk_thread_s *thread; /* management thread */
176 struct mdk_thread_s *sync_thread; /* doing resync or reconstruct */
177 sector_t curr_resync; /* blocks scheduled */
178 unsigned long resync_mark; /* a recent timestamp */
179 sector_t resync_mark_cnt;/* blocks written at resync_mark */
180
181 sector_t resync_max_sectors; /* may be set by personality */
182
183 sector_t resync_mismatches; /* count of sectors where
184 * parity/replica mismatch found
185 */
186 /* recovery/resync flags
187 * NEEDED: we might need to start a resync/recover
188 * RUNNING: a thread is running, or about to be started
189 * SYNC: actually doing a resync, not a recovery
190 * ERR: and IO error was detected - abort the resync/recovery
191 * INTR: someone requested a (clean) early abort.
192 * DONE: thread is done and is waiting to be reaped
193 * REQUEST: user-space has requested a sync (used with SYNC)
194 * CHECK: user-space request for for check-only, no repair
195 */
196 #define MD_RECOVERY_RUNNING 0
197 #define MD_RECOVERY_SYNC 1
198 #define MD_RECOVERY_ERR 2
199 #define MD_RECOVERY_INTR 3
200 #define MD_RECOVERY_DONE 4
201 #define MD_RECOVERY_NEEDED 5
202 #define MD_RECOVERY_REQUESTED 6
203 #define MD_RECOVERY_CHECK 7
204 unsigned long recovery;
205
206 int in_sync; /* know to not need resync */
207 struct semaphore reconfig_sem;
208 atomic_t active;
209
210 int changed; /* true if we might need to reread partition info */
211 int degraded; /* whether md should consider
212 * adding a spare
213 */
214 int barriers_work; /* initialised to true, cleared as soon
215 * as a barrier request to slave
216 * fails. Only supported
217 */
218 struct bio *biolist; /* bios that need to be retried
219 * because BIO_RW_BARRIER is not supported
220 */
221
222 atomic_t recovery_active; /* blocks scheduled, but not written */
223 wait_queue_head_t recovery_wait;
224 sector_t recovery_cp;
225
226 spinlock_t write_lock;
227 wait_queue_head_t sb_wait; /* for waiting on superblock updates */
228 atomic_t pending_writes; /* number of active superblock writes */
229
230 unsigned int safemode; /* if set, update "clean" superblock
231 * when no writes pending.
232 */
233 unsigned int safemode_delay;
234 struct timer_list safemode_timer;
235 atomic_t writes_pending;
236 request_queue_t *queue; /* for plugging ... */
237
238 atomic_t write_behind; /* outstanding async IO */
239 unsigned int max_write_behind; /* 0 = sync */
240
241 struct bitmap *bitmap; /* the bitmap for the device */
242 struct file *bitmap_file; /* the bitmap file */
243 long bitmap_offset; /* offset from superblock of
244 * start of bitmap. May be
245 * negative, but not '0'
246 */
247 long default_bitmap_offset; /* this is the offset to use when
248 * hot-adding a bitmap. It should
249 * eventually be settable by sysfs.
250 */
251
252 struct list_head all_mddevs;
253 };
254
255
256 static inline void rdev_dec_pending(mdk_rdev_t *rdev, mddev_t *mddev)
257 {
258 int faulty = test_bit(Faulty, &rdev->flags);
259 if (atomic_dec_and_test(&rdev->nr_pending) && faulty)
260 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
261 }
262
263 static inline void md_sync_acct(struct block_device *bdev, unsigned long nr_sectors)
264 {
265 atomic_add(nr_sectors, &bdev->bd_contains->bd_disk->sync_io);
266 }
267
268 struct mdk_personality_s
269 {
270 char *name;
271 struct module *owner;
272 int (*make_request)(request_queue_t *q, struct bio *bio);
273 int (*run)(mddev_t *mddev);
274 int (*stop)(mddev_t *mddev);
275 void (*status)(struct seq_file *seq, mddev_t *mddev);
276 /* error_handler must set ->faulty and clear ->in_sync
277 * if appropriate, and should abort recovery if needed
278 */
279 void (*error_handler)(mddev_t *mddev, mdk_rdev_t *rdev);
280 int (*hot_add_disk) (mddev_t *mddev, mdk_rdev_t *rdev);
281 int (*hot_remove_disk) (mddev_t *mddev, int number);
282 int (*spare_active) (mddev_t *mddev);
283 sector_t (*sync_request)(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster);
284 int (*resize) (mddev_t *mddev, sector_t sectors);
285 int (*reshape) (mddev_t *mddev, int raid_disks);
286 int (*reconfig) (mddev_t *mddev, int layout, int chunk_size);
287 /* quiesce moves between quiescence states
288 * 0 - fully active
289 * 1 - no new requests allowed
290 * others - reserved
291 */
292 void (*quiesce) (mddev_t *mddev, int state);
293 };
294
295
296 struct md_sysfs_entry {
297 struct attribute attr;
298 ssize_t (*show)(mddev_t *, char *);
299 ssize_t (*store)(mddev_t *, const char *, size_t);
300 };
301
302
303 static inline char * mdname (mddev_t * mddev)
304 {
305 return mddev->gendisk ? mddev->gendisk->disk_name : "mdX";
306 }
307
308 extern mdk_rdev_t * find_rdev_nr(mddev_t *mddev, int nr);
309
310 /*
311 * iterates through some rdev ringlist. It's safe to remove the
312 * current 'rdev'. Dont touch 'tmp' though.
313 */
314 #define ITERATE_RDEV_GENERIC(head,rdev,tmp) \
315 \
316 for ((tmp) = (head).next; \
317 (rdev) = (list_entry((tmp), mdk_rdev_t, same_set)), \
318 (tmp) = (tmp)->next, (tmp)->prev != &(head) \
319 ; )
320 /*
321 * iterates through the 'same array disks' ringlist
322 */
323 #define ITERATE_RDEV(mddev,rdev,tmp) \
324 ITERATE_RDEV_GENERIC((mddev)->disks,rdev,tmp)
325
326 /*
327 * Iterates through 'pending RAID disks'
328 */
329 #define ITERATE_RDEV_PENDING(rdev,tmp) \
330 ITERATE_RDEV_GENERIC(pending_raid_disks,rdev,tmp)
331
332 typedef struct mdk_thread_s {
333 void (*run) (mddev_t *mddev);
334 mddev_t *mddev;
335 wait_queue_head_t wqueue;
336 unsigned long flags;
337 struct task_struct *tsk;
338 unsigned long timeout;
339 } mdk_thread_t;
340
341 #define THREAD_WAKEUP 0
342
343 #define __wait_event_lock_irq(wq, condition, lock, cmd) \
344 do { \
345 wait_queue_t __wait; \
346 init_waitqueue_entry(&__wait, current); \
347 \
348 add_wait_queue(&wq, &__wait); \
349 for (;;) { \
350 set_current_state(TASK_UNINTERRUPTIBLE); \
351 if (condition) \
352 break; \
353 spin_unlock_irq(&lock); \
354 cmd; \
355 schedule(); \
356 spin_lock_irq(&lock); \
357 } \
358 current->state = TASK_RUNNING; \
359 remove_wait_queue(&wq, &__wait); \
360 } while (0)
361
362 #define wait_event_lock_irq(wq, condition, lock, cmd) \
363 do { \
364 if (condition) \
365 break; \
366 __wait_event_lock_irq(wq, condition, lock, cmd); \
367 } while (0)
368
369 #endif
370