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)
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
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 */
61 sector_t data_offset; /* start of data in array */
62 sector_t sb_start; /* offset of the super block (in 512byte sectors) */
63 int sb_size; /* bytes in the superblock */
64 int preferred_minor; /* autorun support */
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
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
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
86 #define AutoDetected 7 /* added by auto-detect */
87 #define Blocked 8 /* An error occured on an externally
88 * managed array, don't allow writes
89 * until it is cleared */
90 #define StateChanged 9 /* Faulty or Blocked has changed during
91 * interrupt, so it needs to be
92 * notified by the thread */
93 wait_queue_head_t blocked_wait;
95 int desc_nr; /* descriptor index in the superblock */
96 int raid_disk; /* role of device in array */
97 int saved_raid_disk; /* role that device used to have in the
98 * array and could again if we did a partial
99 * resync from the bitmap
101 sector_t recovery_offset;/* If this device has been partially
102 * recovered, this is where we were
106 atomic_t nr_pending; /* number of pending requests.
107 * only maintained for arrays that
108 * support hot removal
110 atomic_t read_errors; /* number of consecutive read errors that
111 * we have tried to ignore.
113 atomic_t corrected_errors; /* number of corrected read errors,
114 * for reporting to userspace and storing
117 struct work_struct del_work; /* used for delayed sysfs removal */
123 struct mdk_personality *pers;
126 struct list_head disks;
128 #define MD_CHANGE_DEVS 0 /* Some device status has changed */
129 #define MD_CHANGE_CLEAN 1 /* transition to or from 'clean' */
130 #define MD_CHANGE_PENDING 2 /* superblock update in progress */
134 struct gendisk *gendisk;
138 /* Superblock information */
143 int external; /* metadata is
144 * managed externally */
145 char metadata_type[17]; /* externally set*/
152 sector_t size; /* used size of component devices */
153 sector_t array_sectors; /* exported array size */
158 /* If the array is being reshaped, we need to record the
159 * new shape and an indication of where we are up to.
160 * This is written to the superblock.
161 * If reshape_position is MaxSector, then no reshape is happening (yet).
163 sector_t reshape_position;
164 int delta_disks, new_level, new_layout, new_chunk;
166 struct mdk_thread_s *thread; /* management thread */
167 struct mdk_thread_s *sync_thread; /* doing resync or reconstruct */
168 sector_t curr_resync; /* last block scheduled */
169 unsigned long resync_mark; /* a recent timestamp */
170 sector_t resync_mark_cnt;/* blocks written at resync_mark */
171 sector_t curr_mark_cnt; /* blocks scheduled now */
173 sector_t resync_max_sectors; /* may be set by personality */
175 sector_t resync_mismatches; /* count of sectors where
176 * parity/replica mismatch found
179 /* allow user-space to request suspension of IO to regions of the array */
182 /* if zero, use the system-wide default */
186 /* resync even though the same disks are shared among md-devices */
189 int ok_start_degraded;
190 /* recovery/resync flags
191 * NEEDED: we might need to start a resync/recover
192 * RUNNING: a thread is running, or about to be started
193 * SYNC: actually doing a resync, not a recovery
194 * RECOVER: doing recovery, or need to try it.
195 * INTR: resync needs to be aborted for some reason
196 * DONE: thread is done and is waiting to be reaped
197 * REQUEST: user-space has requested a sync (used with SYNC)
198 * CHECK: user-space request for for check-only, no repair
199 * RESHAPE: A reshape is happening
201 * If neither SYNC or RESHAPE are set, then it is a recovery.
203 #define MD_RECOVERY_RUNNING 0
204 #define MD_RECOVERY_SYNC 1
205 #define MD_RECOVERY_RECOVER 2
206 #define MD_RECOVERY_INTR 3
207 #define MD_RECOVERY_DONE 4
208 #define MD_RECOVERY_NEEDED 5
209 #define MD_RECOVERY_REQUESTED 6
210 #define MD_RECOVERY_CHECK 7
211 #define MD_RECOVERY_RESHAPE 8
212 #define MD_RECOVERY_FROZEN 9
214 unsigned long recovery;
216 int in_sync; /* know to not need resync */
217 struct mutex reconfig_mutex;
218 atomic_t active; /* general refcount */
219 atomic_t openers; /* number of active opens */
221 int changed; /* true if we might need to reread partition info */
222 int degraded; /* whether md should consider
225 int barriers_work; /* initialised to true, cleared as soon
226 * as a barrier request to slave
227 * fails. Only supported
229 struct bio *biolist; /* bios that need to be retried
230 * because BIO_RW_BARRIER is not supported
233 atomic_t recovery_active; /* blocks scheduled, but not written */
234 wait_queue_head_t recovery_wait;
235 sector_t recovery_cp;
236 sector_t resync_min; /* user requested sync
238 sector_t resync_max; /* resync should pause
239 * when it gets here */
241 spinlock_t write_lock;
242 wait_queue_head_t sb_wait; /* for waiting on superblock updates */
243 atomic_t pending_writes; /* number of active superblock writes */
245 unsigned int safemode; /* if set, update "clean" superblock
246 * when no writes pending.
248 unsigned int safemode_delay;
249 struct timer_list safemode_timer;
250 atomic_t writes_pending;
251 struct request_queue *queue; /* for plugging ... */
253 atomic_t write_behind; /* outstanding async IO */
254 unsigned int max_write_behind; /* 0 = sync */
256 struct bitmap *bitmap; /* the bitmap for the device */
257 struct file *bitmap_file; /* the bitmap file */
258 long bitmap_offset; /* offset from superblock of
259 * start of bitmap. May be
260 * negative, but not '0'
262 long default_bitmap_offset; /* this is the offset to use when
263 * hot-adding a bitmap. It should
264 * eventually be settable by sysfs.
267 struct list_head all_mddevs;
271 static inline void rdev_dec_pending(mdk_rdev_t *rdev, mddev_t *mddev)
273 int faulty = test_bit(Faulty, &rdev->flags);
274 if (atomic_dec_and_test(&rdev->nr_pending) && faulty)
275 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
278 static inline void md_sync_acct(struct block_device *bdev, unsigned long nr_sectors)
280 atomic_add(nr_sectors, &bdev->bd_contains->bd_disk->sync_io);
283 struct mdk_personality
287 struct list_head list;
288 struct module *owner;
289 int (*make_request)(struct request_queue *q, struct bio *bio);
290 int (*run)(mddev_t *mddev);
291 int (*stop)(mddev_t *mddev);
292 void (*status)(struct seq_file *seq, mddev_t *mddev);
293 /* error_handler must set ->faulty and clear ->in_sync
294 * if appropriate, and should abort recovery if needed
296 void (*error_handler)(mddev_t *mddev, mdk_rdev_t *rdev);
297 int (*hot_add_disk) (mddev_t *mddev, mdk_rdev_t *rdev);
298 int (*hot_remove_disk) (mddev_t *mddev, int number);
299 int (*spare_active) (mddev_t *mddev);
300 sector_t (*sync_request)(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster);
301 int (*resize) (mddev_t *mddev, sector_t sectors);
302 int (*check_reshape) (mddev_t *mddev);
303 int (*start_reshape) (mddev_t *mddev);
304 int (*reconfig) (mddev_t *mddev, int layout, int chunk_size);
305 /* quiesce moves between quiescence states
307 * 1 - no new requests allowed
310 void (*quiesce) (mddev_t *mddev, int state);
314 struct md_sysfs_entry {
315 struct attribute attr;
316 ssize_t (*show)(mddev_t *, char *);
317 ssize_t (*store)(mddev_t *, const char *, size_t);
321 static inline char * mdname (mddev_t * mddev)
323 return mddev->gendisk ? mddev->gendisk->disk_name : "mdX";
327 * iterates through some rdev ringlist. It's safe to remove the
328 * current 'rdev'. Dont touch 'tmp' though.
330 #define rdev_for_each_list(rdev, tmp, list) \
332 for ((tmp) = (list).next; \
333 (rdev) = (list_entry((tmp), mdk_rdev_t, same_set)), \
334 (tmp) = (tmp)->next, (tmp)->prev != &(list) \
337 * iterates through the 'same array disks' ringlist
339 #define rdev_for_each(rdev, tmp, mddev) \
340 rdev_for_each_list(rdev, tmp, (mddev)->disks)
342 #define rdev_for_each_rcu(rdev, mddev) \
343 list_for_each_entry_rcu(rdev, &((mddev)->disks), same_set)
345 typedef struct mdk_thread_s {
346 void (*run) (mddev_t *mddev);
348 wait_queue_head_t wqueue;
350 struct task_struct *tsk;
351 unsigned long timeout;
354 #define THREAD_WAKEUP 0
356 #define __wait_event_lock_irq(wq, condition, lock, cmd) \
358 wait_queue_t __wait; \
359 init_waitqueue_entry(&__wait, current); \
361 add_wait_queue(&wq, &__wait); \
363 set_current_state(TASK_UNINTERRUPTIBLE); \
366 spin_unlock_irq(&lock); \
369 spin_lock_irq(&lock); \
371 current->state = TASK_RUNNING; \
372 remove_wait_queue(&wq, &__wait); \
375 #define wait_event_lock_irq(wq, condition, lock, cmd) \
379 __wait_event_lock_irq(wq, condition, lock, cmd); \
382 static inline void safe_put_page(struct page *p)
387 #endif /* CONFIG_BLOCK */