md: allow devices to be shared between md arrays
[linux-2.6/mini2440.git] / include / linux / raid / md_k.h
blob5b2102e40286dd40eb3f469774743778a1b301ac
1 /*
2 md_k.h : kernel internal structure of the Linux MD driver
3 Copyright (C) 1996-98 Ingo Molnar, Gadi Oxman
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.
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.
15 #ifndef _MD_K_H
16 #define _MD_K_H
18 /* and dm-bio-list.h is not under include/linux because.... ??? */
19 #include "../../../drivers/md/dm-bio-list.h"
21 #ifdef CONFIG_BLOCK
23 #define LEVEL_MULTIPATH (-4)
24 #define LEVEL_LINEAR (-1)
25 #define LEVEL_FAULTY (-5)
27 /* we need a value for 'no level specified' and 0
28 * means 'raid0', so we need something else. This is
29 * for internal use only
31 #define LEVEL_NONE (-1000000)
33 #define MaxSector (~(sector_t)0)
35 typedef struct mddev_s mddev_t;
36 typedef struct mdk_rdev_s mdk_rdev_t;
39 * options passed in raidrun:
42 /* Currently this must fit in an 'int' */
43 #define MAX_CHUNK_SIZE (1<<30)
46 * MD's 'extended' device
48 struct mdk_rdev_s
50 struct list_head same_set; /* RAID devices within the same set */
52 sector_t size; /* Device size (in blocks) */
53 mddev_t *mddev; /* RAID array if running */
54 long last_events; /* IO event timestamp */
56 struct block_device *bdev; /* block device handle */
58 struct page *sb_page;
59 int sb_loaded;
60 __u64 sb_events;
61 sector_t data_offset; /* start of data in array */
62 sector_t sb_offset;
63 int sb_size; /* bytes in the superblock */
64 int preferred_minor; /* autorun support */
66 struct kobject kobj;
68 /* A device can be in one of three states based on two flags:
69 * Not working: faulty==1 in_sync==0
70 * Fully working: faulty==0 in_sync==1
71 * Working, but not
72 * in sync with array
73 * faulty==0 in_sync==0
75 * It can never have faulty==1, in_sync==1
76 * This reduces the burden of testing multiple flags in many cases
79 unsigned long flags;
80 #define Faulty 1 /* device is known to have a fault */
81 #define In_sync 2 /* device is in_sync with rest of array */
82 #define WriteMostly 4 /* Avoid reading if at all possible */
83 #define BarriersNotsupp 5 /* BIO_RW_BARRIER is not supported */
84 #define AllReserved 6 /* If whole device is reserved for
85 * one array */
87 int desc_nr; /* descriptor index in the superblock */
88 int raid_disk; /* role of device in array */
89 int saved_raid_disk; /* role that device used to have in the
90 * array and could again if we did a partial
91 * resync from the bitmap
93 sector_t recovery_offset;/* If this device has been partially
94 * recovered, this is where we were
95 * up to.
98 atomic_t nr_pending; /* number of pending requests.
99 * only maintained for arrays that
100 * support hot removal
102 atomic_t read_errors; /* number of consecutive read errors that
103 * we have tried to ignore.
105 atomic_t corrected_errors; /* number of corrected read errors,
106 * for reporting to userspace and storing
107 * in superblock.
109 struct work_struct del_work; /* used for delayed sysfs removal */
112 struct mddev_s
114 void *private;
115 struct mdk_personality *pers;
116 dev_t unit;
117 int md_minor;
118 struct list_head disks;
119 unsigned long flags;
120 #define MD_CHANGE_DEVS 0 /* Some device status has changed */
121 #define MD_CHANGE_CLEAN 1 /* transition to or from 'clean' */
122 #define MD_CHANGE_PENDING 2 /* superblock update in progress */
124 int ro;
126 struct gendisk *gendisk;
128 struct kobject kobj;
130 /* Superblock information */
131 int major_version,
132 minor_version,
133 patch_version;
134 int persistent;
135 int external; /* metadata is
136 * managed externally */
137 char metadata_type[17]; /* externally set*/
138 int chunk_size;
139 time_t ctime, utime;
140 int level, layout;
141 char clevel[16];
142 int raid_disks;
143 int max_disks;
144 sector_t size; /* used size of component devices */
145 sector_t array_size; /* exported array size */
146 __u64 events;
148 char uuid[16];
150 /* If the array is being reshaped, we need to record the
151 * new shape and an indication of where we are up to.
152 * This is written to the superblock.
153 * If reshape_position is MaxSector, then no reshape is happening (yet).
155 sector_t reshape_position;
156 int delta_disks, new_level, new_layout, new_chunk;
158 struct mdk_thread_s *thread; /* management thread */
159 struct mdk_thread_s *sync_thread; /* doing resync or reconstruct */
160 sector_t curr_resync; /* last block scheduled */
161 unsigned long resync_mark; /* a recent timestamp */
162 sector_t resync_mark_cnt;/* blocks written at resync_mark */
163 sector_t curr_mark_cnt; /* blocks scheduled now */
165 sector_t resync_max_sectors; /* may be set by personality */
167 sector_t resync_mismatches; /* count of sectors where
168 * parity/replica mismatch found
171 /* allow user-space to request suspension of IO to regions of the array */
172 sector_t suspend_lo;
173 sector_t suspend_hi;
174 /* if zero, use the system-wide default */
175 int sync_speed_min;
176 int sync_speed_max;
178 int ok_start_degraded;
179 /* recovery/resync flags
180 * NEEDED: we might need to start a resync/recover
181 * RUNNING: a thread is running, or about to be started
182 * SYNC: actually doing a resync, not a recovery
183 * ERR: and IO error was detected - abort the resync/recovery
184 * INTR: someone requested a (clean) early abort.
185 * DONE: thread is done and is waiting to be reaped
186 * REQUEST: user-space has requested a sync (used with SYNC)
187 * CHECK: user-space request for for check-only, no repair
188 * RESHAPE: A reshape is happening
190 * If neither SYNC or RESHAPE are set, then it is a recovery.
192 #define MD_RECOVERY_RUNNING 0
193 #define MD_RECOVERY_SYNC 1
194 #define MD_RECOVERY_ERR 2
195 #define MD_RECOVERY_INTR 3
196 #define MD_RECOVERY_DONE 4
197 #define MD_RECOVERY_NEEDED 5
198 #define MD_RECOVERY_REQUESTED 6
199 #define MD_RECOVERY_CHECK 7
200 #define MD_RECOVERY_RESHAPE 8
201 #define MD_RECOVERY_FROZEN 9
203 unsigned long recovery;
205 int in_sync; /* know to not need resync */
206 struct mutex reconfig_mutex;
207 atomic_t active;
209 int changed; /* true if we might need to reread partition info */
210 int degraded; /* whether md should consider
211 * adding a spare
213 int barriers_work; /* initialised to true, cleared as soon
214 * as a barrier request to slave
215 * fails. Only supported
217 struct bio *biolist; /* bios that need to be retried
218 * because BIO_RW_BARRIER is not supported
221 atomic_t recovery_active; /* blocks scheduled, but not written */
222 wait_queue_head_t recovery_wait;
223 sector_t recovery_cp;
224 sector_t resync_max; /* resync should pause
225 * when it gets here */
227 spinlock_t write_lock;
228 wait_queue_head_t sb_wait; /* for waiting on superblock updates */
229 atomic_t pending_writes; /* number of active superblock writes */
231 unsigned int safemode; /* if set, update "clean" superblock
232 * when no writes pending.
234 unsigned int safemode_delay;
235 struct timer_list safemode_timer;
236 atomic_t writes_pending;
237 struct request_queue *queue; /* for plugging ... */
239 atomic_t write_behind; /* outstanding async IO */
240 unsigned int max_write_behind; /* 0 = sync */
242 struct bitmap *bitmap; /* the bitmap for the device */
243 struct file *bitmap_file; /* the bitmap file */
244 long bitmap_offset; /* offset from superblock of
245 * start of bitmap. May be
246 * negative, but not '0'
248 long default_bitmap_offset; /* this is the offset to use when
249 * hot-adding a bitmap. It should
250 * eventually be settable by sysfs.
253 struct list_head all_mddevs;
257 static inline void rdev_dec_pending(mdk_rdev_t *rdev, mddev_t *mddev)
259 int faulty = test_bit(Faulty, &rdev->flags);
260 if (atomic_dec_and_test(&rdev->nr_pending) && faulty)
261 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
264 static inline void md_sync_acct(struct block_device *bdev, unsigned long nr_sectors)
266 atomic_add(nr_sectors, &bdev->bd_contains->bd_disk->sync_io);
269 struct mdk_personality
271 char *name;
272 int level;
273 struct list_head list;
274 struct module *owner;
275 int (*make_request)(struct request_queue *q, struct bio *bio);
276 int (*run)(mddev_t *mddev);
277 int (*stop)(mddev_t *mddev);
278 void (*status)(struct seq_file *seq, mddev_t *mddev);
279 /* error_handler must set ->faulty and clear ->in_sync
280 * if appropriate, and should abort recovery if needed
282 void (*error_handler)(mddev_t *mddev, mdk_rdev_t *rdev);
283 int (*hot_add_disk) (mddev_t *mddev, mdk_rdev_t *rdev);
284 int (*hot_remove_disk) (mddev_t *mddev, int number);
285 int (*spare_active) (mddev_t *mddev);
286 sector_t (*sync_request)(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster);
287 int (*resize) (mddev_t *mddev, sector_t sectors);
288 int (*check_reshape) (mddev_t *mddev);
289 int (*start_reshape) (mddev_t *mddev);
290 int (*reconfig) (mddev_t *mddev, int layout, int chunk_size);
291 /* quiesce moves between quiescence states
292 * 0 - fully active
293 * 1 - no new requests allowed
294 * others - reserved
296 void (*quiesce) (mddev_t *mddev, int state);
300 struct md_sysfs_entry {
301 struct attribute attr;
302 ssize_t (*show)(mddev_t *, char *);
303 ssize_t (*store)(mddev_t *, const char *, size_t);
307 static inline char * mdname (mddev_t * mddev)
309 return mddev->gendisk ? mddev->gendisk->disk_name : "mdX";
313 * iterates through some rdev ringlist. It's safe to remove the
314 * current 'rdev'. Dont touch 'tmp' though.
316 #define ITERATE_RDEV_GENERIC(head,rdev,tmp) \
318 for ((tmp) = (head).next; \
319 (rdev) = (list_entry((tmp), mdk_rdev_t, same_set)), \
320 (tmp) = (tmp)->next, (tmp)->prev != &(head) \
323 * iterates through the 'same array disks' ringlist
325 #define ITERATE_RDEV(mddev,rdev,tmp) \
326 ITERATE_RDEV_GENERIC((mddev)->disks,rdev,tmp)
329 * Iterates through 'pending RAID disks'
331 #define ITERATE_RDEV_PENDING(rdev,tmp) \
332 ITERATE_RDEV_GENERIC(pending_raid_disks,rdev,tmp)
334 typedef struct mdk_thread_s {
335 void (*run) (mddev_t *mddev);
336 mddev_t *mddev;
337 wait_queue_head_t wqueue;
338 unsigned long flags;
339 struct task_struct *tsk;
340 unsigned long timeout;
341 } mdk_thread_t;
343 #define THREAD_WAKEUP 0
345 #define __wait_event_lock_irq(wq, condition, lock, cmd) \
346 do { \
347 wait_queue_t __wait; \
348 init_waitqueue_entry(&__wait, current); \
350 add_wait_queue(&wq, &__wait); \
351 for (;;) { \
352 set_current_state(TASK_UNINTERRUPTIBLE); \
353 if (condition) \
354 break; \
355 spin_unlock_irq(&lock); \
356 cmd; \
357 schedule(); \
358 spin_lock_irq(&lock); \
360 current->state = TASK_RUNNING; \
361 remove_wait_queue(&wq, &__wait); \
362 } while (0)
364 #define wait_event_lock_irq(wq, condition, lock, cmd) \
365 do { \
366 if (condition) \
367 break; \
368 __wait_event_lock_irq(wq, condition, lock, cmd); \
369 } while (0)
371 static inline void safe_put_page(struct page *p)
373 if (p) put_page(p);
376 #endif /* CONFIG_BLOCK */
377 #endif