drivers/md/md.h

   1 /*
   2    md.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 /* Bad block numbers are stored sorted in a single page.
  30  * 64bits is used for each block or extent.
  31  * 54 bits are sector number, 9 bits are extent size,
  32  * 1 bit is an 'acknowledged' flag.
  33  */
  34 #define MD_MAX_BADBLOCKS        (PAGE_SIZE/8)
  35
  36 /*
  37  * MD's 'extended' device
  38  */
  39 struct md_rdev {
  40         struct list_head same_set;      /* RAID devices within the same set */
  41
  42         sector_t sectors;               /* Device size (in 512bytes sectors) */
  43         struct mddev *mddev;            /* RAID array if running */
  44         int last_events;                /* IO event timestamp */
  45
  46         /*
  47          * If meta_bdev is non-NULL, it means that a separate device is
  48          * being used to store the metadata (superblock/bitmap) which
  49          * would otherwise be contained on the same device as the data (bdev).
  50          */
  51         struct block_device *meta_bdev;
  52         struct block_device *bdev;      /* block device handle */
  53
  54         struct page     *sb_page, *bb_page;
  55         int             sb_loaded;
  56         __u64           sb_events;
  57         sector_t        data_offset;    /* start of data in array */
  58         sector_t        sb_start;       /* offset of the super block (in 512byte sectors) */
  59         int             sb_size;        /* bytes in the superblock */
  60         int             preferred_minor;        /* autorun support */
  61
  62         struct kobject  kobj;
  63
  64         /* A device can be in one of three states based on two flags:
  65          * Not working:   faulty==1 in_sync==0
  66          * Fully working: faulty==0 in_sync==1
  67          * Working, but not
  68          * in sync with array
  69          *                faulty==0 in_sync==0
  70          *
  71          * It can never have faulty==1, in_sync==1
  72          * This reduces the burden of testing multiple flags in many cases
  73          */
  74
  75         unsigned long   flags;  /* bit set of 'enum flag_bits' bits. */
  76         wait_queue_head_t blocked_wait;
  77
  78         int desc_nr;                    /* descriptor index in the superblock */
  79         int raid_disk;                  /* role of device in array */
  80         int new_raid_disk;              /* role that the device will have in
  81                                          * the array after a level-change completes.
  82                                          */
  83         int saved_raid_disk;            /* role that device used to have in the
  84                                          * array and could again if we did a partial
  85                                          * resync from the bitmap
  86                                          */
  87         sector_t        recovery_offset;/* If this device has been partially
  88                                          * recovered, this is where we were
  89                                          * up to.
  90                                          */
  91
  92         atomic_t        nr_pending;     /* number of pending requests.
  93                                          * only maintained for arrays that
  94                                          * support hot removal
  95                                          */
  96         atomic_t        read_errors;    /* number of consecutive read errors that
  97                                          * we have tried to ignore.
  98                                          */
  99         struct timespec last_read_error;        /* monotonic time since our
 100                                                  * last read error
 101                                                  */
 102         atomic_t        corrected_errors; /* number of corrected read errors,
 103                                            * for reporting to userspace and storing
 104                                            * in superblock.
 105                                            */
 106         struct work_struct del_work;    /* used for delayed sysfs removal */
 107
 108         struct sysfs_dirent *sysfs_state; /* handle for 'state'
 109                                            * sysfs entry */
 110
 111         struct badblocks {
 112                 int     count;          /* count of bad blocks */
 113                 int     unacked_exist;  /* there probably are unacknowledged
 114                                          * bad blocks.  This is only cleared
 115                                          * when a read discovers none
 116                                          */
 117                 int     shift;          /* shift from sectors to block size
 118                                          * a -ve shift means badblocks are
 119                                          * disabled.*/
 120                 u64     *page;          /* badblock list */
 121                 int     changed;
 122                 seqlock_t lock;
 123
 124                 sector_t sector;
 125                 sector_t size;          /* in sectors */
 126         } badblocks;
 127 };
 128 enum flag_bits {
 129         Faulty,                 /* device is known to have a fault */
 130         In_sync,                /* device is in_sync with rest of array */
 131         WriteMostly,            /* Avoid reading if at all possible */
 132         AutoDetected,           /* added by auto-detect */
 133         Blocked,                /* An error occurred but has not yet
 134                                  * been acknowledged by the metadata
 135                                  * handler, so don't allow writes
 136                                  * until it is cleared */
 137         WriteErrorSeen,         /* A write error has been seen on this
 138                                  * device
 139                                  */
 140         FaultRecorded,          /* Intermediate state for clearing
 141                                  * Blocked.  The Fault is/will-be
 142                                  * recorded in the metadata, but that
 143                                  * metadata hasn't been stored safely
 144                                  * on disk yet.
 145                                  */
 146         BlockedBadBlocks,       /* A writer is blocked because they
 147                                  * found an unacknowledged bad-block.
 148                                  * This can safely be cleared at any
 149                                  * time, and the writer will re-check.
 150                                  * It may be set at any time, and at
 151                                  * worst the writer will timeout and
 152                                  * re-check.  So setting it as
 153                                  * accurately as possible is good, but
 154                                  * not absolutely critical.
 155                                  */
 156         WantReplacement,        /* This device is a candidate to be
 157                                  * hot-replaced, either because it has
 158                                  * reported some faults, or because
 159                                  * of explicit request.
 160                                  */
 161         Replacement,            /* This device is a replacement for
 162                                  * a want_replacement device with same
 163                                  * raid_disk number.
 164                                  */
 165 };
 166
 167 #define BB_LEN_MASK     (0x00000000000001FFULL)
 168 #define BB_OFFSET_MASK  (0x7FFFFFFFFFFFFE00ULL)
 169 #define BB_ACK_MASK     (0x8000000000000000ULL)
 170 #define BB_MAX_LEN      512
 171 #define BB_OFFSET(x)    (((x) & BB_OFFSET_MASK) >> 9)
 172 #define BB_LEN(x)       (((x) & BB_LEN_MASK) + 1)
 173 #define BB_ACK(x)       (!!((x) & BB_ACK_MASK))
 174 #define BB_MAKE(a, l, ack) (((a)<<9) | ((l)-1) | ((u64)(!!(ack)) << 63))
 175
 176 extern int md_is_badblock(struct badblocks *bb, sector_t s, int sectors,
 177                           sector_t *first_bad, int *bad_sectors);
 178 static inline int is_badblock(struct md_rdev *rdev, sector_t s, int sectors,
 179                               sector_t *first_bad, int *bad_sectors)
 180 {
 181         if (unlikely(rdev->badblocks.count)) {
 182                 int rv = md_is_badblock(&rdev->badblocks, rdev->data_offset + s,
 183                                         sectors,
 184                                         first_bad, bad_sectors);
 185                 if (rv)
 186                         *first_bad -= rdev->data_offset;
 187                 return rv;
 188         }
 189         return 0;
 190 }
 191 extern int rdev_set_badblocks(struct md_rdev *rdev, sector_t s, int sectors,
 192                               int acknowledged);
 193 extern int rdev_clear_badblocks(struct md_rdev *rdev, sector_t s, int sectors);
 194 extern void md_ack_all_badblocks(struct badblocks *bb);
 195
 196 struct mddev {
 197         void                            *private;
 198         struct md_personality           *pers;
 199         dev_t                           unit;
 200         int                             md_minor;
 201         struct list_head                disks;
 202         unsigned long                   flags;
 203 #define MD_CHANGE_DEVS  0       /* Some device status has changed */
 204 #define MD_CHANGE_CLEAN 1       /* transition to or from 'clean' */
 205 #define MD_CHANGE_PENDING 2     /* switch from 'clean' to 'active' in progress */
 206 #define MD_ARRAY_FIRST_USE 3    /* First use of array, needs initialization */
 207
 208         int                             suspended;
 209         atomic_t                        active_io;
 210         int                             ro;
 211         int                             sysfs_active; /* set when sysfs deletes
 212                                                        * are happening, so run/
 213                                                        * takeover/stop are not safe
 214                                                        */
 215         int                             ready; /* See when safe to pass
 216                                                 * IO requests down */
 217         struct gendisk                  *gendisk;
 218
 219         struct kobject                  kobj;
 220         int                             hold_active;
 221 #define UNTIL_IOCTL     1
 222 #define UNTIL_STOP      2
 223
 224         /* Superblock information */
 225         int                             major_version,
 226                                         minor_version,
 227                                         patch_version;
 228         int                             persistent;
 229         int                             external;       /* metadata is
 230                                                          * managed externally */
 231         char                            metadata_type[17]; /* externally set*/
 232         int                             chunk_sectors;
 233         time_t                          ctime, utime;
 234         int                             level, layout;
 235         char                            clevel[16];
 236         int                             raid_disks;
 237         int                             max_disks;
 238         sector_t                        dev_sectors;    /* used size of
 239                                                          * component devices */
 240         sector_t                        array_sectors; /* exported array size */
 241         int                             external_size; /* size managed
 242                                                         * externally */
 243         __u64                           events;
 244         /* If the last 'event' was simply a clean->dirty transition, and
 245          * we didn't write it to the spares, then it is safe and simple
 246          * to just decrement the event count on a dirty->clean transition.
 247          * So we record that possibility here.
 248          */
 249         int                             can_decrease_events;
 250
 251         char                            uuid[16];
 252
 253         /* If the array is being reshaped, we need to record the
 254          * new shape and an indication of where we are up to.
 255          * This is written to the superblock.
 256          * If reshape_position is MaxSector, then no reshape is happening (yet).
 257          */
 258         sector_t                        reshape_position;
 259         int                             delta_disks, new_level, new_layout;
 260         int                             new_chunk_sectors;
 261
 262         atomic_t                        plug_cnt;       /* If device is expecting
 263                                                          * more bios soon.
 264                                                          */
 265         struct md_thread                *thread;        /* management thread */
 266         struct md_thread                *sync_thread;   /* doing resync or reconstruct */
 267         sector_t                        curr_resync;    /* last block scheduled */
 268         /* As resync requests can complete out of order, we cannot easily track
 269          * how much resync has been completed.  So we occasionally pause until
 270          * everything completes, then set curr_resync_completed to curr_resync.
 271          * As such it may be well behind the real resync mark, but it is a value
 272          * we are certain of.
 273          */
 274         sector_t                        curr_resync_completed;
 275         unsigned long                   resync_mark;    /* a recent timestamp */
 276         sector_t                        resync_mark_cnt;/* blocks written at resync_mark */
 277         sector_t                        curr_mark_cnt; /* blocks scheduled now */
 278
 279         sector_t                        resync_max_sectors; /* may be set by personality */
 280
 281         sector_t                        resync_mismatches; /* count of sectors where
 282                                                             * parity/replica mismatch found
 283                                                             */
 284
 285         /* allow user-space to request suspension of IO to regions of the array */
 286         sector_t                        suspend_lo;
 287         sector_t                        suspend_hi;
 288         /* if zero, use the system-wide default */
 289         int                             sync_speed_min;
 290         int                             sync_speed_max;
 291
 292         /* resync even though the same disks are shared among md-devices */
 293         int                             parallel_resync;
 294
 295         int                             ok_start_degraded;
 296         /* recovery/resync flags
 297          * NEEDED:   we might need to start a resync/recover
 298          * RUNNING:  a thread is running, or about to be started
 299          * SYNC:     actually doing a resync, not a recovery
 300          * RECOVER:  doing recovery, or need to try it.
 301          * INTR:     resync needs to be aborted for some reason
 302          * DONE:     thread is done and is waiting to be reaped
 303          * REQUEST:  user-space has requested a sync (used with SYNC)
 304          * CHECK:    user-space request for check-only, no repair
 305          * RESHAPE:  A reshape is happening
 306          *
 307          * If neither SYNC or RESHAPE are set, then it is a recovery.
 308          */
 309 #define MD_RECOVERY_RUNNING     0
 310 #define MD_RECOVERY_SYNC        1
 311 #define MD_RECOVERY_RECOVER     2
 312 #define MD_RECOVERY_INTR        3
 313 #define MD_RECOVERY_DONE        4
 314 #define MD_RECOVERY_NEEDED      5
 315 #define MD_RECOVERY_REQUESTED   6
 316 #define MD_RECOVERY_CHECK       7
 317 #define MD_RECOVERY_RESHAPE     8
 318 #define MD_RECOVERY_FROZEN      9
 319
 320         unsigned long                   recovery;
 321         /* If a RAID personality determines that recovery (of a particular
 322          * device) will fail due to a read error on the source device, it
 323          * takes a copy of this number and does not attempt recovery again
 324          * until this number changes.
 325          */
 326         int                             recovery_disabled;
 327
 328         int                             in_sync;        /* know to not need resync */
 329         /* 'open_mutex' avoids races between 'md_open' and 'do_md_stop', so
 330          * that we are never stopping an array while it is open.
 331          * 'reconfig_mutex' protects all other reconfiguration.
 332          * These locks are separate due to conflicting interactions
 333          * with bdev->bd_mutex.
 334          * Lock ordering is:
 335          *  reconfig_mutex -> bd_mutex : e.g. do_md_run -> revalidate_disk
 336          *  bd_mutex -> open_mutex:  e.g. __blkdev_get -> md_open
 337          */
 338         struct mutex                    open_mutex;
 339         struct mutex                    reconfig_mutex;
 340         atomic_t                        active;         /* general refcount */
 341         atomic_t                        openers;        /* number of active opens */
 342
 343         int                             changed;        /* True if we might need to
 344                                                          * reread partition info */
 345         int                             degraded;       /* whether md should consider
 346                                                          * adding a spare
 347                                                          */
 348
 349         atomic_t                        recovery_active; /* blocks scheduled, but not written */
 350         wait_queue_head_t               recovery_wait;
 351         sector_t                        recovery_cp;
 352         sector_t                        resync_min;     /* user requested sync
 353                                                          * starts here */
 354         sector_t                        resync_max;     /* resync should pause
 355                                                          * when it gets here */
 356
 357         struct sysfs_dirent             *sysfs_state;   /* handle for 'array_state'
 358                                                          * file in sysfs.
 359                                                          */
 360         struct sysfs_dirent             *sysfs_action;  /* handle for 'sync_action' */
 361
 362         struct work_struct del_work;    /* used for delayed sysfs removal */
 363
 364         spinlock_t                      write_lock;
 365         wait_queue_head_t               sb_wait;        /* for waiting on superblock updates */
 366         atomic_t                        pending_writes; /* number of active superblock writes */
 367
 368         unsigned int                    safemode;       /* if set, update "clean" superblock
 369                                                          * when no writes pending.
 370                                                          */
 371         unsigned int                    safemode_delay;
 372         struct timer_list               safemode_timer;
 373         atomic_t                        writes_pending;
 374         struct request_queue            *queue; /* for plugging ... */
 375
 376         struct bitmap                   *bitmap; /* the bitmap for the device */
 377         struct {
 378                 struct file             *file; /* the bitmap file */
 379                 loff_t                  offset; /* offset from superblock of
 380                                                  * start of bitmap. May be
 381                                                  * negative, but not '0'
 382                                                  * For external metadata, offset
 383                                                  * from start of device.
 384                                                  */
 385                 loff_t                  default_offset; /* this is the offset to use when
 386                                                          * hot-adding a bitmap.  It should
 387                                                          * eventually be settable by sysfs.
 388                                                          */
 389                 struct mutex            mutex;
 390                 unsigned long           chunksize;
 391                 unsigned long           daemon_sleep; /* how many jiffies between updates? */
 392                 unsigned long           max_write_behind; /* write-behind mode */
 393                 int                     external;
 394         } bitmap_info;
 395
 396         atomic_t                        max_corr_read_errors; /* max read retries */
 397         struct list_head                all_mddevs;
 398
 399         struct attribute_group          *to_remove;
 400
 401         struct bio_set                  *bio_set;
 402
 403         /* Generic flush handling.
 404          * The last to finish preflush schedules a worker to submit
 405          * the rest of the request (without the REQ_FLUSH flag).
 406          */
 407         struct bio *flush_bio;
 408         atomic_t flush_pending;
 409         struct work_struct flush_work;
 410         struct work_struct event_work;  /* used by dm to report failure event */
 411         void (*sync_super)(struct mddev *mddev, struct md_rdev *rdev);
 412 };
 413
 414
 415 static inline void rdev_dec_pending(struct md_rdev *rdev, struct mddev *mddev)
 416 {
 417         int faulty = test_bit(Faulty, &rdev->flags);
 418         if (atomic_dec_and_test(&rdev->nr_pending) && faulty)
 419                 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
 420 }
 421
 422 static inline void md_sync_acct(struct block_device *bdev, unsigned long nr_sectors)
 423 {
 424         atomic_add(nr_sectors, &bdev->bd_contains->bd_disk->sync_io);
 425 }
 426
 427 struct md_personality
 428 {
 429         char *name;
 430         int level;
 431         struct list_head list;
 432         struct module *owner;
 433         void (*make_request)(struct mddev *mddev, struct bio *bio);
 434         int (*run)(struct mddev *mddev);
 435         int (*stop)(struct mddev *mddev);
 436         void (*status)(struct seq_file *seq, struct mddev *mddev);
 437         /* error_handler must set ->faulty and clear ->in_sync
 438          * if appropriate, and should abort recovery if needed
 439          */
 440         void (*error_handler)(struct mddev *mddev, struct md_rdev *rdev);
 441         int (*hot_add_disk) (struct mddev *mddev, struct md_rdev *rdev);
 442         int (*hot_remove_disk) (struct mddev *mddev, struct md_rdev *rdev);
 443         int (*spare_active) (struct mddev *mddev);
 444         sector_t (*sync_request)(struct mddev *mddev, sector_t sector_nr, int *skipped, int go_faster);
 445         int (*resize) (struct mddev *mddev, sector_t sectors);
 446         sector_t (*size) (struct mddev *mddev, sector_t sectors, int raid_disks);
 447         int (*check_reshape) (struct mddev *mddev);
 448         int (*start_reshape) (struct mddev *mddev);
 449         void (*finish_reshape) (struct mddev *mddev);
 450         /* quiesce moves between quiescence states
 451          * 0 - fully active
 452          * 1 - no new requests allowed
 453          * others - reserved
 454          */
 455         void (*quiesce) (struct mddev *mddev, int state);
 456         /* takeover is used to transition an array from one
 457          * personality to another.  The new personality must be able
 458          * to handle the data in the current layout.
 459          * e.g. 2drive raid1 -> 2drive raid5
 460          *      ndrive raid5 -> degraded n+1drive raid6 with special layout
 461          * If the takeover succeeds, a new 'private' structure is returned.
 462          * This needs to be installed and then ->run used to activate the
 463          * array.
 464          */
 465         void *(*takeover) (struct mddev *mddev);
 466 };
 467
 468
 469 struct md_sysfs_entry {
 470         struct attribute attr;
 471         ssize_t (*show)(struct mddev *, char *);
 472         ssize_t (*store)(struct mddev *, const char *, size_t);
 473 };
 474 extern struct attribute_group md_bitmap_group;
 475
 476 static inline struct sysfs_dirent *sysfs_get_dirent_safe(struct sysfs_dirent *sd, char *name)
 477 {
 478         if (sd)
 479                 return sysfs_get_dirent(sd, NULL, name);
 480         return sd;
 481 }
 482 static inline void sysfs_notify_dirent_safe(struct sysfs_dirent *sd)
 483 {
 484         if (sd)
 485                 sysfs_notify_dirent(sd);
 486 }
 487
 488 static inline char * mdname (struct mddev * mddev)
 489 {
 490         return mddev->gendisk ? mddev->gendisk->disk_name : "mdX";
 491 }
 492
 493 static inline int sysfs_link_rdev(struct mddev *mddev, struct md_rdev *rdev)
 494 {
 495         char nm[20];
 496         if (!test_bit(Replacement, &rdev->flags)) {
 497                 sprintf(nm, "rd%d", rdev->raid_disk);
 498                 return sysfs_create_link(&mddev->kobj, &rdev->kobj, nm);
 499         } else
 500                 return 0;
 501 }
 502
 503 static inline void sysfs_unlink_rdev(struct mddev *mddev, struct md_rdev *rdev)
 504 {
 505         char nm[20];
 506         if (!test_bit(Replacement, &rdev->flags)) {
 507                 sprintf(nm, "rd%d", rdev->raid_disk);
 508                 sysfs_remove_link(&mddev->kobj, nm);
 509         }
 510 }
 511
 512 /*
 513  * iterates through some rdev ringlist. It's safe to remove the
 514  * current 'rdev'. Dont touch 'tmp' though.
 515  */
 516 #define rdev_for_each_list(rdev, tmp, head)                             \
 517         list_for_each_entry_safe(rdev, tmp, head, same_set)
 518
 519 /*
 520  * iterates through the 'same array disks' ringlist
 521  */
 522 #define rdev_for_each(rdev, tmp, mddev)                         \
 523         list_for_each_entry_safe(rdev, tmp, &((mddev)->disks), same_set)
 524
 525 #define rdev_for_each_rcu(rdev, mddev)                          \
 526         list_for_each_entry_rcu(rdev, &((mddev)->disks), same_set)
 527
 528 struct md_thread {
 529         void                    (*run) (struct mddev *mddev);
 530         struct mddev            *mddev;
 531         wait_queue_head_t       wqueue;
 532         unsigned long           flags;
 533         struct task_struct      *tsk;
 534         unsigned long           timeout;
 535 };
 536
 537 #define THREAD_WAKEUP  0
 538
 539 #define __wait_event_lock_irq(wq, condition, lock, cmd)                 \
 540 do {                                                                    \
 541         wait_queue_t __wait;                                            \
 542         init_waitqueue_entry(&__wait, current);                         \
 543                                                                         \
 544         add_wait_queue(&wq, &__wait);                                   \
 545         for (;;) {                                                      \
 546                 set_current_state(TASK_UNINTERRUPTIBLE);                \
 547                 if (condition)                                          \
 548                         break;                                          \
 549                 spin_unlock_irq(&lock);                                 \
 550                 cmd;                                                    \
 551                 schedule();                                             \
 552                 spin_lock_irq(&lock);                                   \
 553         }                                                               \
 554         current->state = TASK_RUNNING;                                  \
 555         remove_wait_queue(&wq, &__wait);                                \
 556 } while (0)
 557
 558 #define wait_event_lock_irq(wq, condition, lock, cmd)                   \
 559 do {                                                                    \
 560         if (condition)                                                  \
 561                 break;                                                  \
 562         __wait_event_lock_irq(wq, condition, lock, cmd);                \
 563 } while (0)
 564
 565 static inline void safe_put_page(struct page *p)
 566 {
 567         if (p) put_page(p);
 568 }
 569
 570 extern int register_md_personality(struct md_personality *p);
 571 extern int unregister_md_personality(struct md_personality *p);
 572 extern struct md_thread *md_register_thread(
 573         void (*run)(struct mddev *mddev),
 574         struct mddev *mddev,
 575         const char *name);
 576 extern void md_unregister_thread(struct md_thread **threadp);
 577 extern void md_wakeup_thread(struct md_thread *thread);
 578 extern void md_check_recovery(struct mddev *mddev);
 579 extern void md_write_start(struct mddev *mddev, struct bio *bi);
 580 extern void md_write_end(struct mddev *mddev);
 581 extern void md_done_sync(struct mddev *mddev, int blocks, int ok);
 582 extern void md_error(struct mddev *mddev, struct md_rdev *rdev);
 583
 584 extern int mddev_congested(struct mddev *mddev, int bits);
 585 extern void md_flush_request(struct mddev *mddev, struct bio *bio);
 586 extern void md_super_write(struct mddev *mddev, struct md_rdev *rdev,
 587                            sector_t sector, int size, struct page *page);
 588 extern void md_super_wait(struct mddev *mddev);
 589 extern int sync_page_io(struct md_rdev *rdev, sector_t sector, int size,
 590                         struct page *page, int rw, bool metadata_op);
 591 extern void md_do_sync(struct mddev *mddev);
 592 extern void md_new_event(struct mddev *mddev);
 593 extern int md_allow_write(struct mddev *mddev);
 594 extern void md_wait_for_blocked_rdev(struct md_rdev *rdev, struct mddev *mddev);
 595 extern void md_set_array_sectors(struct mddev *mddev, sector_t array_sectors);
 596 extern int md_check_no_bitmap(struct mddev *mddev);
 597 extern int md_integrity_register(struct mddev *mddev);
 598 extern void md_integrity_add_rdev(struct md_rdev *rdev, struct mddev *mddev);
 599 extern int strict_strtoul_scaled(const char *cp, unsigned long *res, int scale);
 600 extern void restore_bitmap_write_access(struct file *file);
 601
 602 extern void mddev_init(struct mddev *mddev);
 603 extern int md_run(struct mddev *mddev);
 604 extern void md_stop(struct mddev *mddev);
 605 extern void md_stop_writes(struct mddev *mddev);
 606 extern int md_rdev_init(struct md_rdev *rdev);
 607
 608 extern void mddev_suspend(struct mddev *mddev);
 609 extern void mddev_resume(struct mddev *mddev);
 610 extern struct bio *bio_clone_mddev(struct bio *bio, gfp_t gfp_mask,
 611                                    struct mddev *mddev);
 612 extern struct bio *bio_alloc_mddev(gfp_t gfp_mask, int nr_iovecs,
 613                                    struct mddev *mddev);
 614 extern int mddev_check_plugged(struct mddev *mddev);
 615 extern void md_trim_bio(struct bio *bio, int offset, int size);
 616 #endif /* _MD_MD_H */