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 typedef struct mddev_s mddev_t;
  30
  31 /* Bad block numbers are stored sorted in a single page.
  32  * 64bits is used for each block or extent.
  33  * 54 bits are sector number, 9 bits are extent size,
  34  * 1 bit is an 'acknowledged' flag.
  35  */
  36 #define MD_MAX_BADBLOCKS        (PAGE_SIZE/8)
  37
  38 /*
  39  * MD's 'extended' device
  40  */
  41 struct md_rdev {
  42         struct list_head same_set;      /* RAID devices within the same set */
  43
  44         sector_t sectors;               /* Device size (in 512bytes sectors) */
  45         mddev_t *mddev;                 /* RAID array if running */
  46         int last_events;                /* IO event timestamp */
  47
  48         /*
  49          * If meta_bdev is non-NULL, it means that a separate device is
  50          * being used to store the metadata (superblock/bitmap) which
  51          * would otherwise be contained on the same device as the data (bdev).
  52          */
  53         struct block_device *meta_bdev;
  54         struct block_device *bdev;      /* block device handle */
  55
  56         struct page     *sb_page, *bb_page;
  57         int             sb_loaded;
  58         __u64           sb_events;
  59         sector_t        data_offset;    /* start of data in array */
  60         sector_t        sb_start;       /* offset of the super block (in 512byte sectors) */
  61         int             sb_size;        /* bytes in the superblock */
  62         int             preferred_minor;        /* autorun support */
  63
  64         struct kobject  kobj;
  65
  66         /* A device can be in one of three states based on two flags:
  67          * Not working:   faulty==1 in_sync==0
  68          * Fully working: faulty==0 in_sync==1
  69          * Working, but not
  70          * in sync with array
  71          *                faulty==0 in_sync==0
  72          *
  73          * It can never have faulty==1, in_sync==1
  74          * This reduces the burden of testing multiple flags in many cases
  75          */
  76
  77         unsigned long   flags;
  78 #define Faulty          1               /* device is known to have a fault */
  79 #define In_sync         2               /* device is in_sync with rest of array */
  80 #define WriteMostly     4               /* Avoid reading if at all possible */
  81 #define AutoDetected    7               /* added by auto-detect */
  82 #define Blocked         8               /* An error occurred but has not yet
  83                                          * been acknowledged by the metadata
  84                                          * handler, so don't allow writes
  85                                          * until it is cleared */
  86 #define WriteErrorSeen  9               /* A write error has been seen on this
  87                                          * device
  88                                          */
  89 #define FaultRecorded   10              /* Intermediate state for clearing
  90                                          * Blocked.  The Fault is/will-be
  91                                          * recorded in the metadata, but that
  92                                          * metadata hasn't been stored safely
  93                                          * on disk yet.
  94                                          */
  95 #define BlockedBadBlocks 11             /* A writer is blocked because they
  96                                          * found an unacknowledged bad-block.
  97                                          * This can safely be cleared at any
  98                                          * time, and the writer will re-check.
  99                                          * It may be set at any time, and at
 100                                          * worst the writer will timeout and
 101                                          * re-check.  So setting it as
 102                                          * accurately as possible is good, but
 103                                          * not absolutely critical.
 104                                          */
 105         wait_queue_head_t blocked_wait;
 106
 107         int desc_nr;                    /* descriptor index in the superblock */
 108         int raid_disk;                  /* role of device in array */
 109         int new_raid_disk;              /* role that the device will have in
 110                                          * the array after a level-change completes.
 111                                          */
 112         int saved_raid_disk;            /* role that device used to have in the
 113                                          * array and could again if we did a partial
 114                                          * resync from the bitmap
 115                                          */
 116         sector_t        recovery_offset;/* If this device has been partially
 117                                          * recovered, this is where we were
 118                                          * up to.
 119                                          */
 120
 121         atomic_t        nr_pending;     /* number of pending requests.
 122                                          * only maintained for arrays that
 123                                          * support hot removal
 124                                          */
 125         atomic_t        read_errors;    /* number of consecutive read errors that
 126                                          * we have tried to ignore.
 127                                          */
 128         struct timespec last_read_error;        /* monotonic time since our
 129                                                  * last read error
 130                                                  */
 131         atomic_t        corrected_errors; /* number of corrected read errors,
 132                                            * for reporting to userspace and storing
 133                                            * in superblock.
 134                                            */
 135         struct work_struct del_work;    /* used for delayed sysfs removal */
 136
 137         struct sysfs_dirent *sysfs_state; /* handle for 'state'
 138                                            * sysfs entry */
 139
 140         struct badblocks {
 141                 int     count;          /* count of bad blocks */
 142                 int     unacked_exist;  /* there probably are unacknowledged
 143                                          * bad blocks.  This is only cleared
 144                                          * when a read discovers none
 145                                          */
 146                 int     shift;          /* shift from sectors to block size
 147                                          * a -ve shift means badblocks are
 148                                          * disabled.*/
 149                 u64     *page;          /* badblock list */
 150                 int     changed;
 151                 seqlock_t lock;
 152
 153                 sector_t sector;
 154                 sector_t size;          /* in sectors */
 155         } badblocks;
 156 };
 157
 158 #define BB_LEN_MASK     (0x00000000000001FFULL)
 159 #define BB_OFFSET_MASK  (0x7FFFFFFFFFFFFE00ULL)
 160 #define BB_ACK_MASK     (0x8000000000000000ULL)
 161 #define BB_MAX_LEN      512
 162 #define BB_OFFSET(x)    (((x) & BB_OFFSET_MASK) >> 9)
 163 #define BB_LEN(x)       (((x) & BB_LEN_MASK) + 1)
 164 #define BB_ACK(x)       (!!((x) & BB_ACK_MASK))
 165 #define BB_MAKE(a, l, ack) (((a)<<9) | ((l)-1) | ((u64)(!!(ack)) << 63))
 166
 167 extern int md_is_badblock(struct badblocks *bb, sector_t s, int sectors,
 168                           sector_t *first_bad, int *bad_sectors);
 169 static inline int is_badblock(struct md_rdev *rdev, sector_t s, int sectors,
 170                               sector_t *first_bad, int *bad_sectors)
 171 {
 172         if (unlikely(rdev->badblocks.count)) {
 173                 int rv = md_is_badblock(&rdev->badblocks, rdev->data_offset + s,
 174                                         sectors,
 175                                         first_bad, bad_sectors);
 176                 if (rv)
 177                         *first_bad -= rdev->data_offset;
 178                 return rv;
 179         }
 180         return 0;
 181 }
 182 extern int rdev_set_badblocks(struct md_rdev *rdev, sector_t s, int sectors,
 183                               int acknowledged);
 184 extern int rdev_clear_badblocks(struct md_rdev *rdev, sector_t s, int sectors);
 185 extern void md_ack_all_badblocks(struct badblocks *bb);
 186
 187 struct mddev_s
 188 {
 189         void                            *private;
 190         struct mdk_personality          *pers;
 191         dev_t                           unit;
 192         int                             md_minor;
 193         struct list_head                disks;
 194         unsigned long                   flags;
 195 #define MD_CHANGE_DEVS  0       /* Some device status has changed */
 196 #define MD_CHANGE_CLEAN 1       /* transition to or from 'clean' */
 197 #define MD_CHANGE_PENDING 2     /* switch from 'clean' to 'active' in progress */
 198 #define MD_ARRAY_FIRST_USE 3    /* First use of array, needs initialization */
 199
 200         int                             suspended;
 201         atomic_t                        active_io;
 202         int                             ro;
 203         int                             sysfs_active; /* set when sysfs deletes
 204                                                        * are happening, so run/
 205                                                        * takeover/stop are not safe
 206                                                        */
 207         int                             ready; /* See when safe to pass
 208                                                 * IO requests down */
 209         struct gendisk                  *gendisk;
 210
 211         struct kobject                  kobj;
 212         int                             hold_active;
 213 #define UNTIL_IOCTL     1
 214 #define UNTIL_STOP      2
 215
 216         /* Superblock information */
 217         int                             major_version,
 218                                         minor_version,
 219                                         patch_version;
 220         int                             persistent;
 221         int                             external;       /* metadata is
 222                                                          * managed externally */
 223         char                            metadata_type[17]; /* externally set*/
 224         int                             chunk_sectors;
 225         time_t                          ctime, utime;
 226         int                             level, layout;
 227         char                            clevel[16];
 228         int                             raid_disks;
 229         int                             max_disks;
 230         sector_t                        dev_sectors;    /* used size of
 231                                                          * component devices */
 232         sector_t                        array_sectors; /* exported array size */
 233         int                             external_size; /* size managed
 234                                                         * externally */
 235         __u64                           events;
 236         /* If the last 'event' was simply a clean->dirty transition, and
 237          * we didn't write it to the spares, then it is safe and simple
 238          * to just decrement the event count on a dirty->clean transition.
 239          * So we record that possibility here.
 240          */
 241         int                             can_decrease_events;
 242
 243         char                            uuid[16];
 244
 245         /* If the array is being reshaped, we need to record the
 246          * new shape and an indication of where we are up to.
 247          * This is written to the superblock.
 248          * If reshape_position is MaxSector, then no reshape is happening (yet).
 249          */
 250         sector_t                        reshape_position;
 251         int                             delta_disks, new_level, new_layout;
 252         int                             new_chunk_sectors;
 253
 254         atomic_t                        plug_cnt;       /* If device is expecting
 255                                                          * more bios soon.
 256                                                          */
 257         struct mdk_thread_s             *thread;        /* management thread */
 258         struct mdk_thread_s             *sync_thread;   /* doing resync or reconstruct */
 259         sector_t                        curr_resync;    /* last block scheduled */
 260         /* As resync requests can complete out of order, we cannot easily track
 261          * how much resync has been completed.  So we occasionally pause until
 262          * everything completes, then set curr_resync_completed to curr_resync.
 263          * As such it may be well behind the real resync mark, but it is a value
 264          * we are certain of.
 265          */
 266         sector_t                        curr_resync_completed;
 267         unsigned long                   resync_mark;    /* a recent timestamp */
 268         sector_t                        resync_mark_cnt;/* blocks written at resync_mark */
 269         sector_t                        curr_mark_cnt; /* blocks scheduled now */
 270
 271         sector_t                        resync_max_sectors; /* may be set by personality */
 272
 273         sector_t                        resync_mismatches; /* count of sectors where
 274                                                             * parity/replica mismatch found
 275                                                             */
 276
 277         /* allow user-space to request suspension of IO to regions of the array */
 278         sector_t                        suspend_lo;
 279         sector_t                        suspend_hi;
 280         /* if zero, use the system-wide default */
 281         int                             sync_speed_min;
 282         int                             sync_speed_max;
 283
 284         /* resync even though the same disks are shared among md-devices */
 285         int                             parallel_resync;
 286
 287         int                             ok_start_degraded;
 288         /* recovery/resync flags
 289          * NEEDED:   we might need to start a resync/recover
 290          * RUNNING:  a thread is running, or about to be started
 291          * SYNC:     actually doing a resync, not a recovery
 292          * RECOVER:  doing recovery, or need to try it.
 293          * INTR:     resync needs to be aborted for some reason
 294          * DONE:     thread is done and is waiting to be reaped
 295          * REQUEST:  user-space has requested a sync (used with SYNC)
 296          * CHECK:    user-space request for check-only, no repair
 297          * RESHAPE:  A reshape is happening
 298          *
 299          * If neither SYNC or RESHAPE are set, then it is a recovery.
 300          */
 301 #define MD_RECOVERY_RUNNING     0
 302 #define MD_RECOVERY_SYNC        1
 303 #define MD_RECOVERY_RECOVER     2
 304 #define MD_RECOVERY_INTR        3
 305 #define MD_RECOVERY_DONE        4
 306 #define MD_RECOVERY_NEEDED      5
 307 #define MD_RECOVERY_REQUESTED   6
 308 #define MD_RECOVERY_CHECK       7
 309 #define MD_RECOVERY_RESHAPE     8
 310 #define MD_RECOVERY_FROZEN      9
 311
 312         unsigned long                   recovery;
 313         /* If a RAID personality determines that recovery (of a particular
 314          * device) will fail due to a read error on the source device, it
 315          * takes a copy of this number and does not attempt recovery again
 316          * until this number changes.
 317          */
 318         int                             recovery_disabled;
 319
 320         int                             in_sync;        /* know to not need resync */
 321         /* 'open_mutex' avoids races between 'md_open' and 'do_md_stop', so
 322          * that we are never stopping an array while it is open.
 323          * 'reconfig_mutex' protects all other reconfiguration.
 324          * These locks are separate due to conflicting interactions
 325          * with bdev->bd_mutex.
 326          * Lock ordering is:
 327          *  reconfig_mutex -> bd_mutex : e.g. do_md_run -> revalidate_disk
 328          *  bd_mutex -> open_mutex:  e.g. __blkdev_get -> md_open
 329          */
 330         struct mutex                    open_mutex;
 331         struct mutex                    reconfig_mutex;
 332         atomic_t                        active;         /* general refcount */
 333         atomic_t                        openers;        /* number of active opens */
 334
 335         int                             changed;        /* True if we might need to
 336                                                          * reread partition info */
 337         int                             degraded;       /* whether md should consider
 338                                                          * adding a spare
 339                                                          */
 340
 341         atomic_t                        recovery_active; /* blocks scheduled, but not written */
 342         wait_queue_head_t               recovery_wait;
 343         sector_t                        recovery_cp;
 344         sector_t                        resync_min;     /* user requested sync
 345                                                          * starts here */
 346         sector_t                        resync_max;     /* resync should pause
 347                                                          * when it gets here */
 348
 349         struct sysfs_dirent             *sysfs_state;   /* handle for 'array_state'
 350                                                          * file in sysfs.
 351                                                          */
 352         struct sysfs_dirent             *sysfs_action;  /* handle for 'sync_action' */
 353
 354         struct work_struct del_work;    /* used for delayed sysfs removal */
 355
 356         spinlock_t                      write_lock;
 357         wait_queue_head_t               sb_wait;        /* for waiting on superblock updates */
 358         atomic_t                        pending_writes; /* number of active superblock writes */
 359
 360         unsigned int                    safemode;       /* if set, update "clean" superblock
 361                                                          * when no writes pending.
 362                                                          */
 363         unsigned int                    safemode_delay;
 364         struct timer_list               safemode_timer;
 365         atomic_t                        writes_pending;
 366         struct request_queue            *queue; /* for plugging ... */
 367
 368         struct bitmap                   *bitmap; /* the bitmap for the device */
 369         struct {
 370                 struct file             *file; /* the bitmap file */
 371                 loff_t                  offset; /* offset from superblock of
 372                                                  * start of bitmap. May be
 373                                                  * negative, but not '0'
 374                                                  * For external metadata, offset
 375                                                  * from start of device.
 376                                                  */
 377                 loff_t                  default_offset; /* this is the offset to use when
 378                                                          * hot-adding a bitmap.  It should
 379                                                          * eventually be settable by sysfs.
 380                                                          */
 381                 struct mutex            mutex;
 382                 unsigned long           chunksize;
 383                 unsigned long           daemon_sleep; /* how many jiffies between updates? */
 384                 unsigned long           max_write_behind; /* write-behind mode */
 385                 int                     external;
 386         } bitmap_info;
 387
 388         atomic_t                        max_corr_read_errors; /* max read retries */
 389         struct list_head                all_mddevs;
 390
 391         struct attribute_group          *to_remove;
 392
 393         struct bio_set                  *bio_set;
 394
 395         /* Generic flush handling.
 396          * The last to finish preflush schedules a worker to submit
 397          * the rest of the request (without the REQ_FLUSH flag).
 398          */
 399         struct bio *flush_bio;
 400         atomic_t flush_pending;
 401         struct work_struct flush_work;
 402         struct work_struct event_work;  /* used by dm to report failure event */
 403         void (*sync_super)(mddev_t *mddev, struct md_rdev *rdev);
 404 };
 405
 406
 407 static inline void rdev_dec_pending(struct md_rdev *rdev, mddev_t *mddev)
 408 {
 409         int faulty = test_bit(Faulty, &rdev->flags);
 410         if (atomic_dec_and_test(&rdev->nr_pending) && faulty)
 411                 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
 412 }
 413
 414 static inline void md_sync_acct(struct block_device *bdev, unsigned long nr_sectors)
 415 {
 416         atomic_add(nr_sectors, &bdev->bd_contains->bd_disk->sync_io);
 417 }
 418
 419 struct mdk_personality
 420 {
 421         char *name;
 422         int level;
 423         struct list_head list;
 424         struct module *owner;
 425         int (*make_request)(mddev_t *mddev, struct bio *bio);
 426         int (*run)(mddev_t *mddev);
 427         int (*stop)(mddev_t *mddev);
 428         void (*status)(struct seq_file *seq, mddev_t *mddev);
 429         /* error_handler must set ->faulty and clear ->in_sync
 430          * if appropriate, and should abort recovery if needed
 431          */
 432         void (*error_handler)(mddev_t *mddev, struct md_rdev *rdev);
 433         int (*hot_add_disk) (mddev_t *mddev, struct md_rdev *rdev);
 434         int (*hot_remove_disk) (mddev_t *mddev, int number);
 435         int (*spare_active) (mddev_t *mddev);
 436         sector_t (*sync_request)(mddev_t *mddev, sector_t sector_nr, int *skipped, int go_faster);
 437         int (*resize) (mddev_t *mddev, sector_t sectors);
 438         sector_t (*size) (mddev_t *mddev, sector_t sectors, int raid_disks);
 439         int (*check_reshape) (mddev_t *mddev);
 440         int (*start_reshape) (mddev_t *mddev);
 441         void (*finish_reshape) (mddev_t *mddev);
 442         /* quiesce moves between quiescence states
 443          * 0 - fully active
 444          * 1 - no new requests allowed
 445          * others - reserved
 446          */
 447         void (*quiesce) (mddev_t *mddev, int state);
 448         /* takeover is used to transition an array from one
 449          * personality to another.  The new personality must be able
 450          * to handle the data in the current layout.
 451          * e.g. 2drive raid1 -> 2drive raid5
 452          *      ndrive raid5 -> degraded n+1drive raid6 with special layout
 453          * If the takeover succeeds, a new 'private' structure is returned.
 454          * This needs to be installed and then ->run used to activate the
 455          * array.
 456          */
 457         void *(*takeover) (mddev_t *mddev);
 458 };
 459
 460
 461 struct md_sysfs_entry {
 462         struct attribute attr;
 463         ssize_t (*show)(mddev_t *, char *);
 464         ssize_t (*store)(mddev_t *, const char *, size_t);
 465 };
 466 extern struct attribute_group md_bitmap_group;
 467
 468 static inline struct sysfs_dirent *sysfs_get_dirent_safe(struct sysfs_dirent *sd, char *name)
 469 {
 470         if (sd)
 471                 return sysfs_get_dirent(sd, NULL, name);
 472         return sd;
 473 }
 474 static inline void sysfs_notify_dirent_safe(struct sysfs_dirent *sd)
 475 {
 476         if (sd)
 477                 sysfs_notify_dirent(sd);
 478 }
 479
 480 static inline char * mdname (mddev_t * mddev)
 481 {
 482         return mddev->gendisk ? mddev->gendisk->disk_name : "mdX";
 483 }
 484
 485 static inline int sysfs_link_rdev(mddev_t *mddev, struct md_rdev *rdev)
 486 {
 487         char nm[20];
 488         sprintf(nm, "rd%d", rdev->raid_disk);
 489         return sysfs_create_link(&mddev->kobj, &rdev->kobj, nm);
 490 }
 491
 492 static inline void sysfs_unlink_rdev(mddev_t *mddev, struct md_rdev *rdev)
 493 {
 494         char nm[20];
 495         sprintf(nm, "rd%d", rdev->raid_disk);
 496         sysfs_remove_link(&mddev->kobj, nm);
 497 }
 498
 499 /*
 500  * iterates through some rdev ringlist. It's safe to remove the
 501  * current 'rdev'. Dont touch 'tmp' though.
 502  */
 503 #define rdev_for_each_list(rdev, tmp, head)                             \
 504         list_for_each_entry_safe(rdev, tmp, head, same_set)
 505
 506 /*
 507  * iterates through the 'same array disks' ringlist
 508  */
 509 #define rdev_for_each(rdev, tmp, mddev)                         \
 510         list_for_each_entry_safe(rdev, tmp, &((mddev)->disks), same_set)
 511
 512 #define rdev_for_each_rcu(rdev, mddev)                          \
 513         list_for_each_entry_rcu(rdev, &((mddev)->disks), same_set)
 514
 515 typedef struct mdk_thread_s {
 516         void                    (*run) (mddev_t *mddev);
 517         mddev_t                 *mddev;
 518         wait_queue_head_t       wqueue;
 519         unsigned long           flags;
 520         struct task_struct      *tsk;
 521         unsigned long           timeout;
 522 } mdk_thread_t;
 523
 524 #define THREAD_WAKEUP  0
 525
 526 #define __wait_event_lock_irq(wq, condition, lock, cmd)                 \
 527 do {                                                                    \
 528         wait_queue_t __wait;                                            \
 529         init_waitqueue_entry(&__wait, current);                         \
 530                                                                         \
 531         add_wait_queue(&wq, &__wait);                                   \
 532         for (;;) {                                                      \
 533                 set_current_state(TASK_UNINTERRUPTIBLE);                \
 534                 if (condition)                                          \
 535                         break;                                          \
 536                 spin_unlock_irq(&lock);                                 \
 537                 cmd;                                                    \
 538                 schedule();                                             \
 539                 spin_lock_irq(&lock);                                   \
 540         }                                                               \
 541         current->state = TASK_RUNNING;                                  \
 542         remove_wait_queue(&wq, &__wait);                                \
 543 } while (0)
 544
 545 #define wait_event_lock_irq(wq, condition, lock, cmd)                   \
 546 do {                                                                    \
 547         if (condition)                                                  \
 548                 break;                                                  \
 549         __wait_event_lock_irq(wq, condition, lock, cmd);                \
 550 } while (0)
 551
 552 static inline void safe_put_page(struct page *p)
 553 {
 554         if (p) put_page(p);
 555 }
 556
 557 extern int register_md_personality(struct mdk_personality *p);
 558 extern int unregister_md_personality(struct mdk_personality *p);
 559 extern mdk_thread_t * md_register_thread(void (*run) (mddev_t *mddev),
 560                                 mddev_t *mddev, const char *name);
 561 extern void md_unregister_thread(mdk_thread_t **threadp);
 562 extern void md_wakeup_thread(mdk_thread_t *thread);
 563 extern void md_check_recovery(mddev_t *mddev);
 564 extern void md_write_start(mddev_t *mddev, struct bio *bi);
 565 extern void md_write_end(mddev_t *mddev);
 566 extern void md_done_sync(mddev_t *mddev, int blocks, int ok);
 567 extern void md_error(mddev_t *mddev, struct md_rdev *rdev);
 568
 569 extern int mddev_congested(mddev_t *mddev, int bits);
 570 extern void md_flush_request(mddev_t *mddev, struct bio *bio);
 571 extern void md_super_write(mddev_t *mddev, struct md_rdev *rdev,
 572                            sector_t sector, int size, struct page *page);
 573 extern void md_super_wait(mddev_t *mddev);
 574 extern int sync_page_io(struct md_rdev *rdev, sector_t sector, int size,
 575                         struct page *page, int rw, bool metadata_op);
 576 extern void md_do_sync(mddev_t *mddev);
 577 extern void md_new_event(mddev_t *mddev);
 578 extern int md_allow_write(mddev_t *mddev);
 579 extern void md_wait_for_blocked_rdev(struct md_rdev *rdev, mddev_t *mddev);
 580 extern void md_set_array_sectors(mddev_t *mddev, sector_t array_sectors);
 581 extern int md_check_no_bitmap(mddev_t *mddev);
 582 extern int md_integrity_register(mddev_t *mddev);
 583 extern void md_integrity_add_rdev(struct md_rdev *rdev, mddev_t *mddev);
 584 extern int strict_strtoul_scaled(const char *cp, unsigned long *res, int scale);
 585 extern void restore_bitmap_write_access(struct file *file);
 586
 587 extern void mddev_init(mddev_t *mddev);
 588 extern int md_run(mddev_t *mddev);
 589 extern void md_stop(mddev_t *mddev);
 590 extern void md_stop_writes(mddev_t *mddev);
 591 extern int md_rdev_init(struct md_rdev *rdev);
 592
 593 extern void mddev_suspend(mddev_t *mddev);
 594 extern void mddev_resume(mddev_t *mddev);
 595 extern struct bio *bio_clone_mddev(struct bio *bio, gfp_t gfp_mask,
 596                                    mddev_t *mddev);
 597 extern struct bio *bio_alloc_mddev(gfp_t gfp_mask, int nr_iovecs,
 598                                    mddev_t *mddev);
 599 extern int mddev_check_plugged(mddev_t *mddev);
 600 extern void md_trim_bio(struct bio *bio, int offset, int size);
 601 #endif /* _MD_MD_H */