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        new_data_offset;/* only relevant while reshaping */
  59         sector_t        sb_start;       /* offset of the super block (in 512byte sectors) */
  60         int             sb_size;        /* bytes in the superblock */
  61         int             preferred_minor;        /* autorun support */
  62
  63         struct kobject  kobj;
  64
  65         /* A device can be in one of three states based on two flags:
  66          * Not working:   faulty==1 in_sync==0
  67          * Fully working: faulty==0 in_sync==1
  68          * Working, but not
  69          * in sync with array
  70          *                faulty==0 in_sync==0
  71          *
  72          * It can never have faulty==1, in_sync==1
  73          * This reduces the burden of testing multiple flags in many cases
  74          */
  75
  76         unsigned long   flags;  /* bit set of 'enum flag_bits' bits. */
  77         wait_queue_head_t blocked_wait;
  78
  79         int desc_nr;                    /* descriptor index in the superblock */
  80         int raid_disk;                  /* role of device in array */
  81         int new_raid_disk;              /* role that the device will have in
  82                                          * the array after a level-change completes.
  83                                          */
  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         struct timespec last_read_error;        /* monotonic time since our
 101                                                  * last read error
 102                                                  */
 103         atomic_t        corrected_errors; /* number of corrected read errors,
 104                                            * for reporting to userspace and storing
 105                                            * in superblock.
 106                                            */
 107         struct work_struct del_work;    /* used for delayed sysfs removal */
 108
 109         struct sysfs_dirent *sysfs_state; /* handle for 'state'
 110                                            * sysfs entry */
 111
 112         struct badblocks {
 113                 int     count;          /* count of bad blocks */
 114                 int     unacked_exist;  /* there probably are unacknowledged
 115                                          * bad blocks.  This is only cleared
 116                                          * when a read discovers none
 117                                          */
 118                 int     shift;          /* shift from sectors to block size
 119                                          * a -ve shift means badblocks are
 120                                          * disabled.*/
 121                 u64     *page;          /* badblock list */
 122                 int     changed;
 123                 seqlock_t lock;
 124
 125                 sector_t sector;
 126                 sector_t size;          /* in sectors */
 127         } badblocks;
 128 };
 129 enum flag_bits {
 130         Faulty,                 /* device is known to have a fault */
 131         In_sync,                /* device is in_sync with rest of array */
 132         Unmerged,               /* device is being added to array and should
 133                                  * be considerred for bvec_merge_fn but not
 134                                  * yet for actual IO
 135                                  */
 136         WriteMostly,            /* Avoid reading if at all possible */
 137         AutoDetected,           /* added by auto-detect */
 138         Blocked,                /* An error occurred but has not yet
 139                                  * been acknowledged by the metadata
 140                                  * handler, so don't allow writes
 141                                  * until it is cleared */
 142         WriteErrorSeen,         /* A write error has been seen on this
 143                                  * device
 144                                  */
 145         FaultRecorded,          /* Intermediate state for clearing
 146                                  * Blocked.  The Fault is/will-be
 147                                  * recorded in the metadata, but that
 148                                  * metadata hasn't been stored safely
 149                                  * on disk yet.
 150                                  */
 151         BlockedBadBlocks,       /* A writer is blocked because they
 152                                  * found an unacknowledged bad-block.
 153                                  * This can safely be cleared at any
 154                                  * time, and the writer will re-check.
 155                                  * It may be set at any time, and at
 156                                  * worst the writer will timeout and
 157                                  * re-check.  So setting it as
 158                                  * accurately as possible is good, but
 159                                  * not absolutely critical.
 160                                  */
 161         WantReplacement,        /* This device is a candidate to be
 162                                  * hot-replaced, either because it has
 163                                  * reported some faults, or because
 164                                  * of explicit request.
 165                                  */
 166         Replacement,            /* This device is a replacement for
 167                                  * a want_replacement device with same
 168                                  * raid_disk number.
 169                                  */
 170 };
 171
 172 #define BB_LEN_MASK     (0x00000000000001FFULL)
 173 #define BB_OFFSET_MASK  (0x7FFFFFFFFFFFFE00ULL)
 174 #define BB_ACK_MASK     (0x8000000000000000ULL)
 175 #define BB_MAX_LEN      512
 176 #define BB_OFFSET(x)    (((x) & BB_OFFSET_MASK) >> 9)
 177 #define BB_LEN(x)       (((x) & BB_LEN_MASK) + 1)
 178 #define BB_ACK(x)       (!!((x) & BB_ACK_MASK))
 179 #define BB_MAKE(a, l, ack) (((a)<<9) | ((l)-1) | ((u64)(!!(ack)) << 63))
 180
 181 extern int md_is_badblock(struct badblocks *bb, sector_t s, int sectors,
 182                           sector_t *first_bad, int *bad_sectors);
 183 static inline int is_badblock(struct md_rdev *rdev, sector_t s, int sectors,
 184                               sector_t *first_bad, int *bad_sectors)
 185 {
 186         if (unlikely(rdev->badblocks.count)) {
 187                 int rv = md_is_badblock(&rdev->badblocks, rdev->data_offset + s,
 188                                         sectors,
 189                                         first_bad, bad_sectors);
 190                 if (rv)
 191                         *first_bad -= rdev->data_offset;
 192                 return rv;
 193         }
 194         return 0;
 195 }
 196 extern int rdev_set_badblocks(struct md_rdev *rdev, sector_t s, int sectors,
 197                               int is_new);
 198 extern int rdev_clear_badblocks(struct md_rdev *rdev, sector_t s, int sectors,
 199                                 int is_new);
 200 extern void md_ack_all_badblocks(struct badblocks *bb);
 201
 202 struct mddev {
 203         void                            *private;
 204         struct md_personality           *pers;
 205         dev_t                           unit;
 206         int                             md_minor;
 207         struct list_head                disks;
 208         unsigned long                   flags;
 209 #define MD_CHANGE_DEVS  0       /* Some device status has changed */
 210 #define MD_CHANGE_CLEAN 1       /* transition to or from 'clean' */
 211 #define MD_CHANGE_PENDING 2     /* switch from 'clean' to 'active' in progress */
 212 #define MD_ARRAY_FIRST_USE 3    /* First use of array, needs initialization */
 213
 214         int                             suspended;
 215         atomic_t                        active_io;
 216         int                             ro;
 217         int                             sysfs_active; /* set when sysfs deletes
 218                                                        * are happening, so run/
 219                                                        * takeover/stop are not safe
 220                                                        */
 221         int                             ready; /* See when safe to pass
 222                                                 * IO requests down */
 223         struct gendisk                  *gendisk;
 224
 225         struct kobject                  kobj;
 226         int                             hold_active;
 227 #define UNTIL_IOCTL     1
 228 #define UNTIL_STOP      2
 229
 230         /* Superblock information */
 231         int                             major_version,
 232                                         minor_version,
 233                                         patch_version;
 234         int                             persistent;
 235         int                             external;       /* metadata is
 236                                                          * managed externally */
 237         char                            metadata_type[17]; /* externally set*/
 238         int                             chunk_sectors;
 239         time_t                          ctime, utime;
 240         int                             level, layout;
 241         char                            clevel[16];
 242         int                             raid_disks;
 243         int                             max_disks;
 244         sector_t                        dev_sectors;    /* used size of
 245                                                          * component devices */
 246         sector_t                        array_sectors; /* exported array size */
 247         int                             external_size; /* size managed
 248                                                         * externally */
 249         __u64                           events;
 250         /* If the last 'event' was simply a clean->dirty transition, and
 251          * we didn't write it to the spares, then it is safe and simple
 252          * to just decrement the event count on a dirty->clean transition.
 253          * So we record that possibility here.
 254          */
 255         int                             can_decrease_events;
 256
 257         char                            uuid[16];
 258
 259         /* If the array is being reshaped, we need to record the
 260          * new shape and an indication of where we are up to.
 261          * This is written to the superblock.
 262          * If reshape_position is MaxSector, then no reshape is happening (yet).
 263          */
 264         sector_t                        reshape_position;
 265         int                             delta_disks, new_level, new_layout;
 266         int                             new_chunk_sectors;
 267         int                             reshape_backwards;
 268
 269         struct md_thread                *thread;        /* management thread */
 270         struct md_thread                *sync_thread;   /* doing resync or reconstruct */
 271         sector_t                        curr_resync;    /* last block scheduled */
 272         /* As resync requests can complete out of order, we cannot easily track
 273          * how much resync has been completed.  So we occasionally pause until
 274          * everything completes, then set curr_resync_completed to curr_resync.
 275          * As such it may be well behind the real resync mark, but it is a value
 276          * we are certain of.
 277          */
 278         sector_t                        curr_resync_completed;
 279         unsigned long                   resync_mark;    /* a recent timestamp */
 280         sector_t                        resync_mark_cnt;/* blocks written at resync_mark */
 281         sector_t                        curr_mark_cnt; /* blocks scheduled now */
 282
 283         sector_t                        resync_max_sectors; /* may be set by personality */
 284
 285         sector_t                        resync_mismatches; /* count of sectors where
 286                                                             * parity/replica mismatch found
 287                                                             */
 288
 289         /* allow user-space to request suspension of IO to regions of the array */
 290         sector_t                        suspend_lo;
 291         sector_t                        suspend_hi;
 292         /* if zero, use the system-wide default */
 293         int                             sync_speed_min;
 294         int                             sync_speed_max;
 295
 296         /* resync even though the same disks are shared among md-devices */
 297         int                             parallel_resync;
 298
 299         int                             ok_start_degraded;
 300         /* recovery/resync flags
 301          * NEEDED:   we might need to start a resync/recover
 302          * RUNNING:  a thread is running, or about to be started
 303          * SYNC:     actually doing a resync, not a recovery
 304          * RECOVER:  doing recovery, or need to try it.
 305          * INTR:     resync needs to be aborted for some reason
 306          * DONE:     thread is done and is waiting to be reaped
 307          * REQUEST:  user-space has requested a sync (used with SYNC)
 308          * CHECK:    user-space request for check-only, no repair
 309          * RESHAPE:  A reshape is happening
 310          *
 311          * If neither SYNC or RESHAPE are set, then it is a recovery.
 312          */
 313 #define MD_RECOVERY_RUNNING     0
 314 #define MD_RECOVERY_SYNC        1
 315 #define MD_RECOVERY_RECOVER     2
 316 #define MD_RECOVERY_INTR        3
 317 #define MD_RECOVERY_DONE        4
 318 #define MD_RECOVERY_NEEDED      5
 319 #define MD_RECOVERY_REQUESTED   6
 320 #define MD_RECOVERY_CHECK       7
 321 #define MD_RECOVERY_RESHAPE     8
 322 #define MD_RECOVERY_FROZEN      9
 323
 324         unsigned long                   recovery;
 325         /* If a RAID personality determines that recovery (of a particular
 326          * device) will fail due to a read error on the source device, it
 327          * takes a copy of this number and does not attempt recovery again
 328          * until this number changes.
 329          */
 330         int                             recovery_disabled;
 331
 332         int                             in_sync;        /* know to not need resync */
 333         /* 'open_mutex' avoids races between 'md_open' and 'do_md_stop', so
 334          * that we are never stopping an array while it is open.
 335          * 'reconfig_mutex' protects all other reconfiguration.
 336          * These locks are separate due to conflicting interactions
 337          * with bdev->bd_mutex.
 338          * Lock ordering is:
 339          *  reconfig_mutex -> bd_mutex : e.g. do_md_run -> revalidate_disk
 340          *  bd_mutex -> open_mutex:  e.g. __blkdev_get -> md_open
 341          */
 342         struct mutex                    open_mutex;
 343         struct mutex                    reconfig_mutex;
 344         atomic_t                        active;         /* general refcount */
 345         atomic_t                        openers;        /* number of active opens */
 346
 347         int                             changed;        /* True if we might need to
 348                                                          * reread partition info */
 349         int                             degraded;       /* whether md should consider
 350                                                          * adding a spare
 351                                                          */
 352         int                             merge_check_needed; /* at least one
 353                                                              * member device
 354                                                              * has a
 355                                                              * merge_bvec_fn */
 356
 357         atomic_t                        recovery_active; /* blocks scheduled, but not written */
 358         wait_queue_head_t               recovery_wait;
 359         sector_t                        recovery_cp;
 360         sector_t                        resync_min;     /* user requested sync
 361                                                          * starts here */
 362         sector_t                        resync_max;     /* resync should pause
 363                                                          * when it gets here */
 364
 365         struct sysfs_dirent             *sysfs_state;   /* handle for 'array_state'
 366                                                          * file in sysfs.
 367                                                          */
 368         struct sysfs_dirent             *sysfs_action;  /* handle for 'sync_action' */
 369
 370         struct work_struct del_work;    /* used for delayed sysfs removal */
 371
 372         spinlock_t                      write_lock;
 373         wait_queue_head_t               sb_wait;        /* for waiting on superblock updates */
 374         atomic_t                        pending_writes; /* number of active superblock writes */
 375
 376         unsigned int                    safemode;       /* if set, update "clean" superblock
 377                                                          * when no writes pending.
 378                                                          */
 379         unsigned int                    safemode_delay;
 380         struct timer_list               safemode_timer;
 381         atomic_t                        writes_pending;
 382         struct request_queue            *queue; /* for plugging ... */
 383
 384         struct bitmap                   *bitmap; /* the bitmap for the device */
 385         struct {
 386                 struct file             *file; /* the bitmap file */
 387                 loff_t                  offset; /* offset from superblock of
 388                                                  * start of bitmap. May be
 389                                                  * negative, but not '0'
 390                                                  * For external metadata, offset
 391                                                  * from start of device.
 392                                                  */
 393                 unsigned long           space; /* space available at this offset */
 394                 loff_t                  default_offset; /* this is the offset to use when
 395                                                          * hot-adding a bitmap.  It should
 396                                                          * eventually be settable by sysfs.
 397                                                          */
 398                 unsigned long           default_space; /* space available at
 399                                                         * default offset */
 400                 struct mutex            mutex;
 401                 unsigned long           chunksize;
 402                 unsigned long           daemon_sleep; /* how many jiffies between updates? */
 403                 unsigned long           max_write_behind; /* write-behind mode */
 404                 int                     external;
 405         } bitmap_info;
 406
 407         atomic_t                        max_corr_read_errors; /* max read retries */
 408         struct list_head                all_mddevs;
 409
 410         struct attribute_group          *to_remove;
 411
 412         struct bio_set                  *bio_set;
 413
 414         /* Generic flush handling.
 415          * The last to finish preflush schedules a worker to submit
 416          * the rest of the request (without the REQ_FLUSH flag).
 417          */
 418         struct bio *flush_bio;
 419         atomic_t flush_pending;
 420         struct work_struct flush_work;
 421         struct work_struct event_work;  /* used by dm to report failure event */
 422         void (*sync_super)(struct mddev *mddev, struct md_rdev *rdev);
 423 };
 424
 425
 426 static inline void rdev_dec_pending(struct md_rdev *rdev, struct mddev *mddev)
 427 {
 428         int faulty = test_bit(Faulty, &rdev->flags);
 429         if (atomic_dec_and_test(&rdev->nr_pending) && faulty)
 430                 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
 431 }
 432
 433 static inline void md_sync_acct(struct block_device *bdev, unsigned long nr_sectors)
 434 {
 435         atomic_add(nr_sectors, &bdev->bd_contains->bd_disk->sync_io);
 436 }
 437
 438 struct md_personality
 439 {
 440         char *name;
 441         int level;
 442         struct list_head list;
 443         struct module *owner;
 444         void (*make_request)(struct mddev *mddev, struct bio *bio);
 445         int (*run)(struct mddev *mddev);
 446         int (*stop)(struct mddev *mddev);
 447         void (*status)(struct seq_file *seq, struct mddev *mddev);
 448         /* error_handler must set ->faulty and clear ->in_sync
 449          * if appropriate, and should abort recovery if needed
 450          */
 451         void (*error_handler)(struct mddev *mddev, struct md_rdev *rdev);
 452         int (*hot_add_disk) (struct mddev *mddev, struct md_rdev *rdev);
 453         int (*hot_remove_disk) (struct mddev *mddev, struct md_rdev *rdev);
 454         int (*spare_active) (struct mddev *mddev);
 455         sector_t (*sync_request)(struct mddev *mddev, sector_t sector_nr, int *skipped, int go_faster);
 456         int (*resize) (struct mddev *mddev, sector_t sectors);
 457         sector_t (*size) (struct mddev *mddev, sector_t sectors, int raid_disks);
 458         int (*check_reshape) (struct mddev *mddev);
 459         int (*start_reshape) (struct mddev *mddev);
 460         void (*finish_reshape) (struct mddev *mddev);
 461         /* quiesce moves between quiescence states
 462          * 0 - fully active
 463          * 1 - no new requests allowed
 464          * others - reserved
 465          */
 466         void (*quiesce) (struct mddev *mddev, int state);
 467         /* takeover is used to transition an array from one
 468          * personality to another.  The new personality must be able
 469          * to handle the data in the current layout.
 470          * e.g. 2drive raid1 -> 2drive raid5
 471          *      ndrive raid5 -> degraded n+1drive raid6 with special layout
 472          * If the takeover succeeds, a new 'private' structure is returned.
 473          * This needs to be installed and then ->run used to activate the
 474          * array.
 475          */
 476         void *(*takeover) (struct mddev *mddev);
 477 };
 478
 479
 480 struct md_sysfs_entry {
 481         struct attribute attr;
 482         ssize_t (*show)(struct mddev *, char *);
 483         ssize_t (*store)(struct mddev *, const char *, size_t);
 484 };
 485 extern struct attribute_group md_bitmap_group;
 486
 487 static inline struct sysfs_dirent *sysfs_get_dirent_safe(struct sysfs_dirent *sd, char *name)
 488 {
 489         if (sd)
 490                 return sysfs_get_dirent(sd, NULL, name);
 491         return sd;
 492 }
 493 static inline void sysfs_notify_dirent_safe(struct sysfs_dirent *sd)
 494 {
 495         if (sd)
 496                 sysfs_notify_dirent(sd);
 497 }
 498
 499 static inline char * mdname (struct mddev * mddev)
 500 {
 501         return mddev->gendisk ? mddev->gendisk->disk_name : "mdX";
 502 }
 503
 504 static inline int sysfs_link_rdev(struct mddev *mddev, struct md_rdev *rdev)
 505 {
 506         char nm[20];
 507         if (!test_bit(Replacement, &rdev->flags)) {
 508                 sprintf(nm, "rd%d", rdev->raid_disk);
 509                 return sysfs_create_link(&mddev->kobj, &rdev->kobj, nm);
 510         } else
 511                 return 0;
 512 }
 513
 514 static inline void sysfs_unlink_rdev(struct mddev *mddev, struct md_rdev *rdev)
 515 {
 516         char nm[20];
 517         if (!test_bit(Replacement, &rdev->flags)) {
 518                 sprintf(nm, "rd%d", rdev->raid_disk);
 519                 sysfs_remove_link(&mddev->kobj, nm);
 520         }
 521 }
 522
 523 /*
 524  * iterates through some rdev ringlist. It's safe to remove the
 525  * current 'rdev'. Dont touch 'tmp' though.
 526  */
 527 #define rdev_for_each_list(rdev, tmp, head)                             \
 528         list_for_each_entry_safe(rdev, tmp, head, same_set)
 529
 530 /*
 531  * iterates through the 'same array disks' ringlist
 532  */
 533 #define rdev_for_each(rdev, mddev)                              \
 534         list_for_each_entry(rdev, &((mddev)->disks), same_set)
 535
 536 #define rdev_for_each_safe(rdev, tmp, mddev)                            \
 537         list_for_each_entry_safe(rdev, tmp, &((mddev)->disks), same_set)
 538
 539 #define rdev_for_each_rcu(rdev, mddev)                          \
 540         list_for_each_entry_rcu(rdev, &((mddev)->disks), same_set)
 541
 542 struct md_thread {
 543         void                    (*run) (struct mddev *mddev);
 544         struct mddev            *mddev;
 545         wait_queue_head_t       wqueue;
 546         unsigned long           flags;
 547         struct task_struct      *tsk;
 548         unsigned long           timeout;
 549 };
 550
 551 #define THREAD_WAKEUP  0
 552
 553 #define __wait_event_lock_irq(wq, condition, lock, cmd)                 \
 554 do {                                                                    \
 555         wait_queue_t __wait;                                            \
 556         init_waitqueue_entry(&__wait, current);                         \
 557                                                                         \
 558         add_wait_queue(&wq, &__wait);                                   \
 559         for (;;) {                                                      \
 560                 set_current_state(TASK_UNINTERRUPTIBLE);                \
 561                 if (condition)                                          \
 562                         break;                                          \
 563                 spin_unlock_irq(&lock);                                 \
 564                 cmd;                                                    \
 565                 schedule();                                             \
 566                 spin_lock_irq(&lock);                                   \
 567         }                                                               \
 568         current->state = TASK_RUNNING;                                  \
 569         remove_wait_queue(&wq, &__wait);                                \
 570 } while (0)
 571
 572 #define wait_event_lock_irq(wq, condition, lock, cmd)                   \
 573 do {                                                                    \
 574         if (condition)                                                  \
 575                 break;                                                  \
 576         __wait_event_lock_irq(wq, condition, lock, cmd);                \
 577 } while (0)
 578
 579 static inline void safe_put_page(struct page *p)
 580 {
 581         if (p) put_page(p);
 582 }
 583
 584 extern int register_md_personality(struct md_personality *p);
 585 extern int unregister_md_personality(struct md_personality *p);
 586 extern struct md_thread *md_register_thread(
 587         void (*run)(struct mddev *mddev),
 588         struct mddev *mddev,
 589         const char *name);
 590 extern void md_unregister_thread(struct md_thread **threadp);
 591 extern void md_wakeup_thread(struct md_thread *thread);
 592 extern void md_check_recovery(struct mddev *mddev);
 593 extern void md_write_start(struct mddev *mddev, struct bio *bi);
 594 extern void md_write_end(struct mddev *mddev);
 595 extern void md_done_sync(struct mddev *mddev, int blocks, int ok);
 596 extern void md_error(struct mddev *mddev, struct md_rdev *rdev);
 597 extern void md_finish_reshape(struct mddev *mddev);
 598
 599 extern int mddev_congested(struct mddev *mddev, int bits);
 600 extern void md_flush_request(struct mddev *mddev, struct bio *bio);
 601 extern void md_super_write(struct mddev *mddev, struct md_rdev *rdev,
 602                            sector_t sector, int size, struct page *page);
 603 extern void md_super_wait(struct mddev *mddev);
 604 extern int sync_page_io(struct md_rdev *rdev, sector_t sector, int size,
 605                         struct page *page, int rw, bool metadata_op);
 606 extern void md_do_sync(struct mddev *mddev);
 607 extern void md_new_event(struct mddev *mddev);
 608 extern int md_allow_write(struct mddev *mddev);
 609 extern void md_wait_for_blocked_rdev(struct md_rdev *rdev, struct mddev *mddev);
 610 extern void md_set_array_sectors(struct mddev *mddev, sector_t array_sectors);
 611 extern int md_check_no_bitmap(struct mddev *mddev);
 612 extern int md_integrity_register(struct mddev *mddev);
 613 extern void md_integrity_add_rdev(struct md_rdev *rdev, struct mddev *mddev);
 614 extern int strict_strtoul_scaled(const char *cp, unsigned long *res, int scale);
 615 extern void restore_bitmap_write_access(struct file *file);
 616
 617 extern void mddev_init(struct mddev *mddev);
 618 extern int md_run(struct mddev *mddev);
 619 extern void md_stop(struct mddev *mddev);
 620 extern void md_stop_writes(struct mddev *mddev);
 621 extern int md_rdev_init(struct md_rdev *rdev);
 622 extern void md_rdev_clear(struct md_rdev *rdev);
 623
 624 extern void mddev_suspend(struct mddev *mddev);
 625 extern void mddev_resume(struct mddev *mddev);
 626 extern struct bio *bio_clone_mddev(struct bio *bio, gfp_t gfp_mask,
 627                                    struct mddev *mddev);
 628 extern struct bio *bio_alloc_mddev(gfp_t gfp_mask, int nr_iovecs,
 629                                    struct mddev *mddev);
 630 extern void md_trim_bio(struct bio *bio, int offset, int size);
 631
 632 extern void md_unplug(struct blk_plug_cb *cb, bool from_schedule);
 633 static inline int mddev_check_plugged(struct mddev *mddev)
 634 {
 635         return !!blk_check_plugged(md_unplug, mddev,
 636                                    sizeof(struct blk_plug_cb));
 637 }
 638 #endif /* _MD_MD_H */