drm/i915: Refactor calls to unmap_mapping_range
[linux-2.6] / drivers / md / md.h
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
29 typedef struct mddev_s mddev_t;
30 typedef struct mdk_rdev_s mdk_rdev_t;
31
32 /*
33  * MD's 'extended' device
34  */
35 struct 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
110 struct 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 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         struct mutex                    reconfig_mutex;
227         atomic_t                        active;         /* general refcount */
228         atomic_t                        openers;        /* number of active opens */
229
230         int                             changed;        /* true if we might need to reread partition info */
231         int                             degraded;       /* whether md should consider
232                                                          * adding a spare
233                                                          */
234         int                             barriers_work;  /* initialised to true, cleared as soon
235                                                          * as a barrier request to slave
236                                                          * fails.  Only supported
237                                                          */
238         struct bio                      *biolist;       /* bios that need to be retried
239                                                          * because BIO_RW_BARRIER is not supported
240                                                          */
241
242         atomic_t                        recovery_active; /* blocks scheduled, but not written */
243         wait_queue_head_t               recovery_wait;
244         sector_t                        recovery_cp;
245         sector_t                        resync_min;     /* user requested sync
246                                                          * starts here */
247         sector_t                        resync_max;     /* resync should pause
248                                                          * when it gets here */
249
250         struct sysfs_dirent             *sysfs_state;   /* handle for 'array_state'
251                                                          * file in sysfs.
252                                                          */
253         struct sysfs_dirent             *sysfs_action;  /* handle for 'sync_action' */
254
255         struct work_struct del_work;    /* used for delayed sysfs removal */
256
257         spinlock_t                      write_lock;
258         wait_queue_head_t               sb_wait;        /* for waiting on superblock updates */
259         atomic_t                        pending_writes; /* number of active superblock writes */
260
261         unsigned int                    safemode;       /* if set, update "clean" superblock
262                                                          * when no writes pending.
263                                                          */ 
264         unsigned int                    safemode_delay;
265         struct timer_list               safemode_timer;
266         atomic_t                        writes_pending; 
267         struct request_queue            *queue; /* for plugging ... */
268
269         atomic_t                        write_behind; /* outstanding async IO */
270         unsigned int                    max_write_behind; /* 0 = sync */
271
272         struct bitmap                   *bitmap; /* the bitmap for the device */
273         struct file                     *bitmap_file; /* the bitmap file */
274         long                            bitmap_offset; /* offset from superblock of
275                                                         * start of bitmap. May be
276                                                         * negative, but not '0'
277                                                         */
278         long                            default_bitmap_offset; /* this is the offset to use when
279                                                                 * hot-adding a bitmap.  It should
280                                                                 * eventually be settable by sysfs.
281                                                                 */
282
283         struct list_head                all_mddevs;
284 };
285
286
287 static inline void rdev_dec_pending(mdk_rdev_t *rdev, mddev_t *mddev)
288 {
289         int faulty = test_bit(Faulty, &rdev->flags);
290         if (atomic_dec_and_test(&rdev->nr_pending) && faulty)
291                 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
292 }
293
294 static inline void md_sync_acct(struct block_device *bdev, unsigned long nr_sectors)
295 {
296         atomic_add(nr_sectors, &bdev->bd_contains->bd_disk->sync_io);
297 }
298
299 struct mdk_personality
300 {
301         char *name;
302         int level;
303         struct list_head list;
304         struct module *owner;
305         int (*make_request)(struct request_queue *q, struct bio *bio);
306         int (*run)(mddev_t *mddev);
307         int (*stop)(mddev_t *mddev);
308         void (*status)(struct seq_file *seq, mddev_t *mddev);
309         /* error_handler must set ->faulty and clear ->in_sync
310          * if appropriate, and should abort recovery if needed 
311          */
312         void (*error_handler)(mddev_t *mddev, mdk_rdev_t *rdev);
313         int (*hot_add_disk) (mddev_t *mddev, mdk_rdev_t *rdev);
314         int (*hot_remove_disk) (mddev_t *mddev, int number);
315         int (*spare_active) (mddev_t *mddev);
316         sector_t (*sync_request)(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster);
317         int (*resize) (mddev_t *mddev, sector_t sectors);
318         sector_t (*size) (mddev_t *mddev, sector_t sectors, int raid_disks);
319         int (*check_reshape) (mddev_t *mddev);
320         int (*start_reshape) (mddev_t *mddev);
321         void (*finish_reshape) (mddev_t *mddev);
322         /* quiesce moves between quiescence states
323          * 0 - fully active
324          * 1 - no new requests allowed
325          * others - reserved
326          */
327         void (*quiesce) (mddev_t *mddev, int state);
328         /* takeover is used to transition an array from one
329          * personality to another.  The new personality must be able
330          * to handle the data in the current layout.
331          * e.g. 2drive raid1 -> 2drive raid5
332          *      ndrive raid5 -> degraded n+1drive raid6 with special layout
333          * If the takeover succeeds, a new 'private' structure is returned.
334          * This needs to be installed and then ->run used to activate the
335          * array.
336          */
337         void *(*takeover) (mddev_t *mddev);
338 };
339
340
341 struct md_sysfs_entry {
342         struct attribute attr;
343         ssize_t (*show)(mddev_t *, char *);
344         ssize_t (*store)(mddev_t *, const char *, size_t);
345 };
346
347
348 static inline char * mdname (mddev_t * mddev)
349 {
350         return mddev->gendisk ? mddev->gendisk->disk_name : "mdX";
351 }
352
353 /*
354  * iterates through some rdev ringlist. It's safe to remove the
355  * current 'rdev'. Dont touch 'tmp' though.
356  */
357 #define rdev_for_each_list(rdev, tmp, head)                             \
358         list_for_each_entry_safe(rdev, tmp, head, same_set)
359
360 /*
361  * iterates through the 'same array disks' ringlist
362  */
363 #define rdev_for_each(rdev, tmp, mddev)                         \
364         list_for_each_entry_safe(rdev, tmp, &((mddev)->disks), same_set)
365
366 #define rdev_for_each_rcu(rdev, mddev)                          \
367         list_for_each_entry_rcu(rdev, &((mddev)->disks), same_set)
368
369 typedef struct mdk_thread_s {
370         void                    (*run) (mddev_t *mddev);
371         mddev_t                 *mddev;
372         wait_queue_head_t       wqueue;
373         unsigned long           flags;
374         struct task_struct      *tsk;
375         unsigned long           timeout;
376 } mdk_thread_t;
377
378 #define THREAD_WAKEUP  0
379
380 #define __wait_event_lock_irq(wq, condition, lock, cmd)                 \
381 do {                                                                    \
382         wait_queue_t __wait;                                            \
383         init_waitqueue_entry(&__wait, current);                         \
384                                                                         \
385         add_wait_queue(&wq, &__wait);                                   \
386         for (;;) {                                                      \
387                 set_current_state(TASK_UNINTERRUPTIBLE);                \
388                 if (condition)                                          \
389                         break;                                          \
390                 spin_unlock_irq(&lock);                                 \
391                 cmd;                                                    \
392                 schedule();                                             \
393                 spin_lock_irq(&lock);                                   \
394         }                                                               \
395         current->state = TASK_RUNNING;                                  \
396         remove_wait_queue(&wq, &__wait);                                \
397 } while (0)
398
399 #define wait_event_lock_irq(wq, condition, lock, cmd)                   \
400 do {                                                                    \
401         if (condition)                                                  \
402                 break;                                                  \
403         __wait_event_lock_irq(wq, condition, lock, cmd);                \
404 } while (0)
405
406 static inline void safe_put_page(struct page *p)
407 {
408         if (p) put_page(p);
409 }
410
411 extern int register_md_personality(struct mdk_personality *p);
412 extern int unregister_md_personality(struct mdk_personality *p);
413 extern mdk_thread_t * md_register_thread(void (*run) (mddev_t *mddev),
414                                 mddev_t *mddev, const char *name);
415 extern void md_unregister_thread(mdk_thread_t *thread);
416 extern void md_wakeup_thread(mdk_thread_t *thread);
417 extern void md_check_recovery(mddev_t *mddev);
418 extern void md_write_start(mddev_t *mddev, struct bio *bi);
419 extern void md_write_end(mddev_t *mddev);
420 extern void md_done_sync(mddev_t *mddev, int blocks, int ok);
421 extern void md_error(mddev_t *mddev, mdk_rdev_t *rdev);
422
423 extern void md_super_write(mddev_t *mddev, mdk_rdev_t *rdev,
424                            sector_t sector, int size, struct page *page);
425 extern void md_super_wait(mddev_t *mddev);
426 extern int sync_page_io(struct block_device *bdev, sector_t sector, int size,
427                         struct page *page, int rw);
428 extern void md_do_sync(mddev_t *mddev);
429 extern void md_new_event(mddev_t *mddev);
430 extern int md_allow_write(mddev_t *mddev);
431 extern void md_wait_for_blocked_rdev(mdk_rdev_t *rdev, mddev_t *mddev);
432 extern void md_set_array_sectors(mddev_t *mddev, sector_t array_sectors);
433 extern int md_check_no_bitmap(mddev_t *mddev);
434
435 #endif /* _MD_MD_H */