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)
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.
18 /* and dm-bio-list.h is not under include/linux because.... ??? */
19 #include "../../../drivers/md/dm-bio-list.h"
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)
34 #define MD_THREAD_NAME_MAX 14
36 typedef struct mddev_s mddev_t;
37 typedef struct mdk_rdev_s mdk_rdev_t;
39 #define MAX_MD_DEVS 256 /* Max number of md dev */
42 * options passed in raidrun:
45 /* Currently this must fix in an 'int' */
46 #define MAX_CHUNK_SIZE (1<<30)
49 * MD's 'extended' device
53 struct list_head same_set; /* RAID devices within the same set */
55 sector_t size; /* Device size (in blocks) */
56 mddev_t *mddev; /* RAID array if running */
57 unsigned long last_events; /* IO event timestamp */
59 struct block_device *bdev; /* block device handle */
64 sector_t data_offset; /* start of data in array */
66 int sb_size; /* bytes in the superblock */
67 int preferred_minor; /* autorun support */
71 /* A device can be in one of three states based on two flags:
72 * Not working: faulty==1 in_sync==0
73 * Fully working: faulty==0 in_sync==1
76 * faulty==0 in_sync==0
78 * It can never have faulty==1, in_sync==1
79 * This reduces the burden of testing multiple flags in many cases
83 #define Faulty 1 /* device is known to have a fault */
84 #define In_sync 2 /* device is in_sync with rest of array */
85 #define WriteMostly 4 /* Avoid reading if at all possible */
86 #define BarriersNotsupp 5 /* BIO_RW_BARRIER is not supported */
88 int desc_nr; /* descriptor index in the superblock */
89 int raid_disk; /* role of device in array */
90 int saved_raid_disk; /* role that device used to have in the
91 * array and could again if we did a partial
92 * resync from the bitmap
94 sector_t recovery_offset;/* If this device has been partially
95 * recovered, this is where we were
99 atomic_t nr_pending; /* number of pending requests.
100 * only maintained for arrays that
101 * support hot removal
103 atomic_t read_errors; /* number of consecutive read errors that
104 * we have tried to ignore.
106 atomic_t corrected_errors; /* number of corrected read errors,
107 * for reporting to userspace and storing
115 struct mdk_personality *pers;
118 struct list_head disks;
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 */
126 struct gendisk *gendisk;
130 /* Superblock information */
141 sector_t size; /* used size of component devices */
142 sector_t array_size; /* exported array size */
147 /* If the array is being reshaped, we need to record the
148 * new shape and an indication of where we are up to.
149 * This is written to the superblock.
150 * If reshape_position is MaxSector, then no reshape is happening (yet).
152 sector_t reshape_position;
153 int delta_disks, new_level, new_layout, new_chunk;
155 struct mdk_thread_s *thread; /* management thread */
156 struct mdk_thread_s *sync_thread; /* doing resync or reconstruct */
157 sector_t curr_resync; /* last block scheduled */
158 unsigned long resync_mark; /* a recent timestamp */
159 sector_t resync_mark_cnt;/* blocks written at resync_mark */
160 sector_t curr_mark_cnt; /* blocks scheduled now */
162 sector_t resync_max_sectors; /* may be set by personality */
164 sector_t resync_mismatches; /* count of sectors where
165 * parity/replica mismatch found
168 /* allow user-space to request suspension of IO to regions of the array */
171 /* if zero, use the system-wide default */
175 int ok_start_degraded;
176 /* recovery/resync flags
177 * NEEDED: we might need to start a resync/recover
178 * RUNNING: a thread is running, or about to be started
179 * SYNC: actually doing a resync, not a recovery
180 * ERR: and IO error was detected - abort the resync/recovery
181 * INTR: someone requested a (clean) early abort.
182 * DONE: thread is done and is waiting to be reaped
183 * REQUEST: user-space has requested a sync (used with SYNC)
184 * CHECK: user-space request for for check-only, no repair
185 * RESHAPE: A reshape is happening
187 * If neither SYNC or RESHAPE are set, then it is a recovery.
189 #define MD_RECOVERY_RUNNING 0
190 #define MD_RECOVERY_SYNC 1
191 #define MD_RECOVERY_ERR 2
192 #define MD_RECOVERY_INTR 3
193 #define MD_RECOVERY_DONE 4
194 #define MD_RECOVERY_NEEDED 5
195 #define MD_RECOVERY_REQUESTED 6
196 #define MD_RECOVERY_CHECK 7
197 #define MD_RECOVERY_RESHAPE 8
198 #define MD_RECOVERY_FROZEN 9
200 unsigned long recovery;
202 int in_sync; /* know to not need resync */
203 struct mutex reconfig_mutex;
206 int changed; /* true if we might need to reread partition info */
207 int degraded; /* whether md should consider
210 int barriers_work; /* initialised to true, cleared as soon
211 * as a barrier request to slave
212 * fails. Only supported
214 struct bio *biolist; /* bios that need to be retried
215 * because BIO_RW_BARRIER is not supported
218 atomic_t recovery_active; /* blocks scheduled, but not written */
219 wait_queue_head_t recovery_wait;
220 sector_t recovery_cp;
222 spinlock_t write_lock;
223 wait_queue_head_t sb_wait; /* for waiting on superblock updates */
224 atomic_t pending_writes; /* number of active superblock writes */
226 unsigned int safemode; /* if set, update "clean" superblock
227 * when no writes pending.
229 unsigned int safemode_delay;
230 struct timer_list safemode_timer;
231 atomic_t writes_pending;
232 request_queue_t *queue; /* for plugging ... */
234 atomic_t write_behind; /* outstanding async IO */
235 unsigned int max_write_behind; /* 0 = sync */
237 struct bitmap *bitmap; /* the bitmap for the device */
238 struct file *bitmap_file; /* the bitmap file */
239 long bitmap_offset; /* offset from superblock of
240 * start of bitmap. May be
241 * negative, but not '0'
243 long default_bitmap_offset; /* this is the offset to use when
244 * hot-adding a bitmap. It should
245 * eventually be settable by sysfs.
248 struct list_head all_mddevs;
252 static inline void rdev_dec_pending(mdk_rdev_t *rdev, mddev_t *mddev)
254 int faulty = test_bit(Faulty, &rdev->flags);
255 if (atomic_dec_and_test(&rdev->nr_pending) && faulty)
256 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
259 static inline void md_sync_acct(struct block_device *bdev, unsigned long nr_sectors)
261 atomic_add(nr_sectors, &bdev->bd_contains->bd_disk->sync_io);
264 struct mdk_personality
268 struct list_head list;
269 struct module *owner;
270 int (*make_request)(request_queue_t *q, struct bio *bio);
271 int (*run)(mddev_t *mddev);
272 int (*stop)(mddev_t *mddev);
273 void (*status)(struct seq_file *seq, mddev_t *mddev);
274 /* error_handler must set ->faulty and clear ->in_sync
275 * if appropriate, and should abort recovery if needed
277 void (*error_handler)(mddev_t *mddev, mdk_rdev_t *rdev);
278 int (*hot_add_disk) (mddev_t *mddev, mdk_rdev_t *rdev);
279 int (*hot_remove_disk) (mddev_t *mddev, int number);
280 int (*spare_active) (mddev_t *mddev);
281 sector_t (*sync_request)(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster);
282 int (*resize) (mddev_t *mddev, sector_t sectors);
283 int (*check_reshape) (mddev_t *mddev);
284 int (*start_reshape) (mddev_t *mddev);
285 int (*reconfig) (mddev_t *mddev, int layout, int chunk_size);
286 /* quiesce moves between quiescence states
288 * 1 - no new requests allowed
291 void (*quiesce) (mddev_t *mddev, int state);
295 struct md_sysfs_entry {
296 struct attribute attr;
297 ssize_t (*show)(mddev_t *, char *);
298 ssize_t (*store)(mddev_t *, const char *, size_t);
302 static inline char * mdname (mddev_t * mddev)
304 return mddev->gendisk ? mddev->gendisk->disk_name : "mdX";
308 * iterates through some rdev ringlist. It's safe to remove the
309 * current 'rdev'. Dont touch 'tmp' though.
311 #define ITERATE_RDEV_GENERIC(head,rdev,tmp) \
313 for ((tmp) = (head).next; \
314 (rdev) = (list_entry((tmp), mdk_rdev_t, same_set)), \
315 (tmp) = (tmp)->next, (tmp)->prev != &(head) \
318 * iterates through the 'same array disks' ringlist
320 #define ITERATE_RDEV(mddev,rdev,tmp) \
321 ITERATE_RDEV_GENERIC((mddev)->disks,rdev,tmp)
324 * Iterates through 'pending RAID disks'
326 #define ITERATE_RDEV_PENDING(rdev,tmp) \
327 ITERATE_RDEV_GENERIC(pending_raid_disks,rdev,tmp)
329 typedef struct mdk_thread_s {
330 void (*run) (mddev_t *mddev);
332 wait_queue_head_t wqueue;
334 struct task_struct *tsk;
335 unsigned long timeout;
338 #define THREAD_WAKEUP 0
340 #define __wait_event_lock_irq(wq, condition, lock, cmd) \
342 wait_queue_t __wait; \
343 init_waitqueue_entry(&__wait, current); \
345 add_wait_queue(&wq, &__wait); \
347 set_current_state(TASK_UNINTERRUPTIBLE); \
350 spin_unlock_irq(&lock); \
353 spin_lock_irq(&lock); \
355 current->state = TASK_RUNNING; \
356 remove_wait_queue(&wq, &__wait); \
359 #define wait_event_lock_irq(wq, condition, lock, cmd) \
363 __wait_event_lock_irq(wq, condition, lock, cmd); \
366 static inline void safe_put_page(struct page *p)
371 #endif /* CONFIG_BLOCK */