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 kernfs_node *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         Bitmap_sync,            /* ..actually, not quite In_sync.  Need a
 133                                  * bitmap-based recovery to get fully in sync
 134                                  */
 135         Unmerged,               /* device is being added to array and should
 136                                  * be considerred for bvec_merge_fn but not
 137                                  * yet for actual IO
 138                                  */
 139         WriteMostly,            /* Avoid reading if at all possible */
 140         AutoDetected,           /* added by auto-detect */
 141         Blocked,                /* An error occurred but has not yet
 142                                  * been acknowledged by the metadata
 143                                  * handler, so don't allow writes
 144                                  * until it is cleared */
 145         WriteErrorSeen,         /* A write error has been seen on this
 146                                  * device
 147                                  */
 148         FaultRecorded,          /* Intermediate state for clearing
 149                                  * Blocked.  The Fault is/will-be
 150                                  * recorded in the metadata, but that
 151                                  * metadata hasn't been stored safely
 152                                  * on disk yet.
 153                                  */
 154         BlockedBadBlocks,       /* A writer is blocked because they
 155                                  * found an unacknowledged bad-block.
 156                                  * This can safely be cleared at any
 157                                  * time, and the writer will re-check.
 158                                  * It may be set at any time, and at
 159                                  * worst the writer will timeout and
 160                                  * re-check.  So setting it as
 161                                  * accurately as possible is good, but
 162                                  * not absolutely critical.
 163                                  */
 164         WantReplacement,        /* This device is a candidate to be
 165                                  * hot-replaced, either because it has
 166                                  * reported some faults, or because
 167                                  * of explicit request.
 168                                  */
 169         Replacement,            /* This device is a replacement for
 170                                  * a want_replacement device with same
 171                                  * raid_disk number.
 172                                  */
 173 };
 174
 175 #define BB_LEN_MASK     (0x00000000000001FFULL)
 176 #define BB_OFFSET_MASK  (0x7FFFFFFFFFFFFE00ULL)
 177 #define BB_ACK_MASK     (0x8000000000000000ULL)
 178 #define BB_MAX_LEN      512
 179 #define BB_OFFSET(x)    (((x) & BB_OFFSET_MASK) >> 9)
 180 #define BB_LEN(x)       (((x) & BB_LEN_MASK) + 1)
 181 #define BB_ACK(x)       (!!((x) & BB_ACK_MASK))
 182 #define BB_MAKE(a, l, ack) (((a)<<9) | ((l)-1) | ((u64)(!!(ack)) << 63))
 183
 184 extern int md_is_badblock(struct badblocks *bb, sector_t s, int sectors,
 185                           sector_t *first_bad, int *bad_sectors);
 186 static inline int is_badblock(struct md_rdev *rdev, sector_t s, int sectors,
 187                               sector_t *first_bad, int *bad_sectors)
 188 {
 189         if (unlikely(rdev->badblocks.count)) {
 190                 int rv = md_is_badblock(&rdev->badblocks, rdev->data_offset + s,
 191                                         sectors,
 192                                         first_bad, bad_sectors);
 193                 if (rv)
 194                         *first_bad -= rdev->data_offset;
 195                 return rv;
 196         }
 197         return 0;
 198 }
 199 extern int rdev_set_badblocks(struct md_rdev *rdev, sector_t s, int sectors,
 200                               int is_new);
 201 extern int rdev_clear_badblocks(struct md_rdev *rdev, sector_t s, int sectors,
 202                                 int is_new);
 203 extern void md_ack_all_badblocks(struct badblocks *bb);
 204
 205 struct mddev {
 206         void                            *private;
 207         struct md_personality           *pers;
 208         dev_t                           unit;
 209         int                             md_minor;
 210         struct list_head                disks;
 211         unsigned long                   flags;
 212 #define MD_CHANGE_DEVS  0       /* Some device status has changed */
 213 #define MD_CHANGE_CLEAN 1       /* transition to or from 'clean' */
 214 #define MD_CHANGE_PENDING 2     /* switch from 'clean' to 'active' in progress */
 215 #define MD_UPDATE_SB_FLAGS (1 | 2 | 4)  /* If these are set, md_update_sb needed */
 216 #define MD_ARRAY_FIRST_USE 3    /* First use of array, needs initialization */
 217 #define MD_STILL_CLOSED 4       /* If set, then array has not been opened since
 218                                  * md_ioctl checked on it.
 219                                  */
 220
 221         int                             suspended;
 222         atomic_t                        active_io;
 223         int                             ro;
 224         int                             sysfs_active; /* set when sysfs deletes
 225                                                        * are happening, so run/
 226                                                        * takeover/stop are not safe
 227                                                        */
 228         int                             ready; /* See when safe to pass
 229                                                 * IO requests down */
 230         struct gendisk                  *gendisk;
 231
 232         struct kobject                  kobj;
 233         int                             hold_active;
 234 #define UNTIL_IOCTL     1
 235 #define UNTIL_STOP      2
 236
 237         /* Superblock information */
 238         int                             major_version,
 239                                         minor_version,
 240                                         patch_version;
 241         int                             persistent;
 242         int                             external;       /* metadata is
 243                                                          * managed externally */
 244         char                            metadata_type[17]; /* externally set*/
 245         int                             chunk_sectors;
 246         time_t                          ctime, utime;
 247         int                             level, layout;
 248         char                            clevel[16];
 249         int                             raid_disks;
 250         int                             max_disks;
 251         sector_t                        dev_sectors;    /* used size of
 252                                                          * component devices */
 253         sector_t                        array_sectors; /* exported array size */
 254         int                             external_size; /* size managed
 255                                                         * externally */
 256         __u64                           events;
 257         /* If the last 'event' was simply a clean->dirty transition, and
 258          * we didn't write it to the spares, then it is safe and simple
 259          * to just decrement the event count on a dirty->clean transition.
 260          * So we record that possibility here.
 261          */
 262         int                             can_decrease_events;
 263
 264         char                            uuid[16];
 265
 266         /* If the array is being reshaped, we need to record the
 267          * new shape and an indication of where we are up to.
 268          * This is written to the superblock.
 269          * If reshape_position is MaxSector, then no reshape is happening (yet).
 270          */
 271         sector_t                        reshape_position;
 272         int                             delta_disks, new_level, new_layout;
 273         int                             new_chunk_sectors;
 274         int                             reshape_backwards;
 275
 276         struct md_thread                *thread;        /* management thread */
 277         struct md_thread                *sync_thread;   /* doing resync or reconstruct */
 278
 279         /* 'last_sync_action' is initialized to "none".  It is set when a
 280          * sync operation (i.e "data-check", "requested-resync", "resync",
 281          * "recovery", or "reshape") is started.  It holds this value even
 282          * when the sync thread is "frozen" (interrupted) or "idle" (stopped
 283          * or finished).  It is overwritten when a new sync operation is begun.
 284          */
 285         char                            *last_sync_action;
 286         sector_t                        curr_resync;    /* last block scheduled */
 287         /* As resync requests can complete out of order, we cannot easily track
 288          * how much resync has been completed.  So we occasionally pause until
 289          * everything completes, then set curr_resync_completed to curr_resync.
 290          * As such it may be well behind the real resync mark, but it is a value
 291          * we are certain of.
 292          */
 293         sector_t                        curr_resync_completed;
 294         unsigned long                   resync_mark;    /* a recent timestamp */
 295         sector_t                        resync_mark_cnt;/* blocks written at resync_mark */
 296         sector_t                        curr_mark_cnt; /* blocks scheduled now */
 297
 298         sector_t                        resync_max_sectors; /* may be set by personality */
 299
 300         atomic64_t                      resync_mismatches; /* count of sectors where
 301                                                             * parity/replica mismatch found
 302                                                             */
 303
 304         /* allow user-space to request suspension of IO to regions of the array */
 305         sector_t                        suspend_lo;
 306         sector_t                        suspend_hi;
 307         /* if zero, use the system-wide default */
 308         int                             sync_speed_min;
 309         int                             sync_speed_max;
 310
 311         /* resync even though the same disks are shared among md-devices */
 312         int                             parallel_resync;
 313
 314         int                             ok_start_degraded;
 315         /* recovery/resync flags
 316          * NEEDED:   we might need to start a resync/recover
 317          * RUNNING:  a thread is running, or about to be started
 318          * SYNC:     actually doing a resync, not a recovery
 319          * RECOVER:  doing recovery, or need to try it.
 320          * INTR:     resync needs to be aborted for some reason
 321          * DONE:     thread is done and is waiting to be reaped
 322          * REQUEST:  user-space has requested a sync (used with SYNC)
 323          * CHECK:    user-space request for check-only, no repair
 324          * RESHAPE:  A reshape is happening
 325          * ERROR:    sync-action interrupted because io-error
 326          *
 327          * If neither SYNC or RESHAPE are set, then it is a recovery.
 328          */
 329 #define MD_RECOVERY_RUNNING     0
 330 #define MD_RECOVERY_SYNC        1
 331 #define MD_RECOVERY_RECOVER     2
 332 #define MD_RECOVERY_INTR        3
 333 #define MD_RECOVERY_DONE        4
 334 #define MD_RECOVERY_NEEDED      5
 335 #define MD_RECOVERY_REQUESTED   6
 336 #define MD_RECOVERY_CHECK       7
 337 #define MD_RECOVERY_RESHAPE     8
 338 #define MD_RECOVERY_FROZEN      9
 339 #define MD_RECOVERY_ERROR       10
 340
 341         unsigned long                   recovery;
 342         /* If a RAID personality determines that recovery (of a particular
 343          * device) will fail due to a read error on the source device, it
 344          * takes a copy of this number and does not attempt recovery again
 345          * until this number changes.
 346          */
 347         int                             recovery_disabled;
 348
 349         int                             in_sync;        /* know to not need resync */
 350         /* 'open_mutex' avoids races between 'md_open' and 'do_md_stop', so
 351          * that we are never stopping an array while it is open.
 352          * 'reconfig_mutex' protects all other reconfiguration.
 353          * These locks are separate due to conflicting interactions
 354          * with bdev->bd_mutex.
 355          * Lock ordering is:
 356          *  reconfig_mutex -> bd_mutex : e.g. do_md_run -> revalidate_disk
 357          *  bd_mutex -> open_mutex:  e.g. __blkdev_get -> md_open
 358          */
 359         struct mutex                    open_mutex;
 360         struct mutex                    reconfig_mutex;
 361         atomic_t                        active;         /* general refcount */
 362         atomic_t                        openers;        /* number of active opens */
 363
 364         int                             changed;        /* True if we might need to
 365                                                          * reread partition info */
 366         int                             degraded;       /* whether md should consider
 367                                                          * adding a spare
 368                                                          */
 369         int                             merge_check_needed; /* at least one
 370                                                              * member device
 371                                                              * has a
 372                                                              * merge_bvec_fn */
 373
 374         atomic_t                        recovery_active; /* blocks scheduled, but not written */
 375         wait_queue_head_t               recovery_wait;
 376         sector_t                        recovery_cp;
 377         sector_t                        resync_min;     /* user requested sync
 378                                                          * starts here */
 379         sector_t                        resync_max;     /* resync should pause
 380                                                          * when it gets here */
 381
 382         struct kernfs_node              *sysfs_state;   /* handle for 'array_state'
 383                                                          * file in sysfs.
 384                                                          */
 385         struct kernfs_node              *sysfs_action;  /* handle for 'sync_action' */
 386
 387         struct work_struct del_work;    /* used for delayed sysfs removal */
 388
 389         /* "lock" protects:
 390          *   flush_bio transition from NULL to !NULL
 391          *   rdev superblocks, events
 392          *   clearing MD_CHANGE_*
 393          *   in_sync - and related safemode and MD_CHANGE changes
 394          *   pers (also protected by reconfig_mutex and pending IO).
 395          *   clearing ->bitmap
 396          *   clearing ->bitmap_info.file
 397          */
 398         spinlock_t                      lock;
 399         wait_queue_head_t               sb_wait;        /* for waiting on superblock updates */
 400         atomic_t                        pending_writes; /* number of active superblock writes */
 401
 402         unsigned int                    safemode;       /* if set, update "clean" superblock
 403                                                          * when no writes pending.
 404                                                          */
 405         unsigned int                    safemode_delay;
 406         struct timer_list               safemode_timer;
 407         atomic_t                        writes_pending;
 408         struct request_queue            *queue; /* for plugging ... */
 409
 410         struct bitmap                   *bitmap; /* the bitmap for the device */
 411         struct {
 412                 struct file             *file; /* the bitmap file */
 413                 loff_t                  offset; /* offset from superblock of
 414                                                  * start of bitmap. May be
 415                                                  * negative, but not '0'
 416                                                  * For external metadata, offset
 417                                                  * from start of device.
 418                                                  */
 419                 unsigned long           space; /* space available at this offset */
 420                 loff_t                  default_offset; /* this is the offset to use when
 421                                                          * hot-adding a bitmap.  It should
 422                                                          * eventually be settable by sysfs.
 423                                                          */
 424                 unsigned long           default_space; /* space available at
 425                                                         * default offset */
 426                 struct mutex            mutex;
 427                 unsigned long           chunksize;
 428                 unsigned long           daemon_sleep; /* how many jiffies between updates? */
 429                 unsigned long           max_write_behind; /* write-behind mode */
 430                 int                     external;
 431         } bitmap_info;
 432
 433         atomic_t                        max_corr_read_errors; /* max read retries */
 434         struct list_head                all_mddevs;
 435
 436         struct attribute_group          *to_remove;
 437
 438         struct bio_set                  *bio_set;
 439
 440         /* Generic flush handling.
 441          * The last to finish preflush schedules a worker to submit
 442          * the rest of the request (without the REQ_FLUSH flag).
 443          */
 444         struct bio *flush_bio;
 445         atomic_t flush_pending;
 446         struct work_struct flush_work;
 447         struct work_struct event_work;  /* used by dm to report failure event */
 448         void (*sync_super)(struct mddev *mddev, struct md_rdev *rdev);
 449 };
 450
 451 static inline void rdev_dec_pending(struct md_rdev *rdev, struct mddev *mddev)
 452 {
 453         int faulty = test_bit(Faulty, &rdev->flags);
 454         if (atomic_dec_and_test(&rdev->nr_pending) && faulty)
 455                 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
 456 }
 457
 458 static inline void md_sync_acct(struct block_device *bdev, unsigned long nr_sectors)
 459 {
 460         atomic_add(nr_sectors, &bdev->bd_contains->bd_disk->sync_io);
 461 }
 462
 463 struct md_personality
 464 {
 465         char *name;
 466         int level;
 467         struct list_head list;
 468         struct module *owner;
 469         void (*make_request)(struct mddev *mddev, struct bio *bio);
 470         int (*run)(struct mddev *mddev);
 471         void (*free)(struct mddev *mddev, void *priv);
 472         void (*status)(struct seq_file *seq, struct mddev *mddev);
 473         /* error_handler must set ->faulty and clear ->in_sync
 474          * if appropriate, and should abort recovery if needed
 475          */
 476         void (*error_handler)(struct mddev *mddev, struct md_rdev *rdev);
 477         int (*hot_add_disk) (struct mddev *mddev, struct md_rdev *rdev);
 478         int (*hot_remove_disk) (struct mddev *mddev, struct md_rdev *rdev);
 479         int (*spare_active) (struct mddev *mddev);
 480         sector_t (*sync_request)(struct mddev *mddev, sector_t sector_nr, int *skipped, int go_faster);
 481         int (*resize) (struct mddev *mddev, sector_t sectors);
 482         sector_t (*size) (struct mddev *mddev, sector_t sectors, int raid_disks);
 483         int (*check_reshape) (struct mddev *mddev);
 484         int (*start_reshape) (struct mddev *mddev);
 485         void (*finish_reshape) (struct mddev *mddev);
 486         /* quiesce moves between quiescence states
 487          * 0 - fully active
 488          * 1 - no new requests allowed
 489          * others - reserved
 490          */
 491         void (*quiesce) (struct mddev *mddev, int state);
 492         /* takeover is used to transition an array from one
 493          * personality to another.  The new personality must be able
 494          * to handle the data in the current layout.
 495          * e.g. 2drive raid1 -> 2drive raid5
 496          *      ndrive raid5 -> degraded n+1drive raid6 with special layout
 497          * If the takeover succeeds, a new 'private' structure is returned.
 498          * This needs to be installed and then ->run used to activate the
 499          * array.
 500          */
 501         void *(*takeover) (struct mddev *mddev);
 502         /* congested implements bdi.congested_fn().
 503          * Will not be called while array is 'suspended' */
 504         int (*congested)(struct mddev *mddev, int bits);
 505         /* mergeable_bvec is use to implement ->merge_bvec_fn */
 506         int (*mergeable_bvec)(struct mddev *mddev,
 507                               struct bvec_merge_data *bvm,
 508                               struct bio_vec *biovec);
 509 };
 510
 511 struct md_sysfs_entry {
 512         struct attribute attr;
 513         ssize_t (*show)(struct mddev *, char *);
 514         ssize_t (*store)(struct mddev *, const char *, size_t);
 515 };
 516 extern struct attribute_group md_bitmap_group;
 517
 518 static inline struct kernfs_node *sysfs_get_dirent_safe(struct kernfs_node *sd, char *name)
 519 {
 520         if (sd)
 521                 return sysfs_get_dirent(sd, name);
 522         return sd;
 523 }
 524 static inline void sysfs_notify_dirent_safe(struct kernfs_node *sd)
 525 {
 526         if (sd)
 527                 sysfs_notify_dirent(sd);
 528 }
 529
 530 static inline char * mdname (struct mddev * mddev)
 531 {
 532         return mddev->gendisk ? mddev->gendisk->disk_name : "mdX";
 533 }
 534
 535 static inline int sysfs_link_rdev(struct mddev *mddev, struct md_rdev *rdev)
 536 {
 537         char nm[20];
 538         if (!test_bit(Replacement, &rdev->flags) && mddev->kobj.sd) {
 539                 sprintf(nm, "rd%d", rdev->raid_disk);
 540                 return sysfs_create_link(&mddev->kobj, &rdev->kobj, nm);
 541         } else
 542                 return 0;
 543 }
 544
 545 static inline void sysfs_unlink_rdev(struct mddev *mddev, struct md_rdev *rdev)
 546 {
 547         char nm[20];
 548         if (!test_bit(Replacement, &rdev->flags) && mddev->kobj.sd) {
 549                 sprintf(nm, "rd%d", rdev->raid_disk);
 550                 sysfs_remove_link(&mddev->kobj, nm);
 551         }
 552 }
 553
 554 /*
 555  * iterates through some rdev ringlist. It's safe to remove the
 556  * current 'rdev'. Dont touch 'tmp' though.
 557  */
 558 #define rdev_for_each_list(rdev, tmp, head)                             \
 559         list_for_each_entry_safe(rdev, tmp, head, same_set)
 560
 561 /*
 562  * iterates through the 'same array disks' ringlist
 563  */
 564 #define rdev_for_each(rdev, mddev)                              \
 565         list_for_each_entry(rdev, &((mddev)->disks), same_set)
 566
 567 #define rdev_for_each_safe(rdev, tmp, mddev)                            \
 568         list_for_each_entry_safe(rdev, tmp, &((mddev)->disks), same_set)
 569
 570 #define rdev_for_each_rcu(rdev, mddev)                          \
 571         list_for_each_entry_rcu(rdev, &((mddev)->disks), same_set)
 572
 573 struct md_thread {
 574         void                    (*run) (struct md_thread *thread);
 575         struct mddev            *mddev;
 576         wait_queue_head_t       wqueue;
 577         unsigned long           flags;
 578         struct task_struct      *tsk;
 579         unsigned long           timeout;
 580         void                    *private;
 581 };
 582
 583 #define THREAD_WAKEUP  0
 584
 585 static inline void safe_put_page(struct page *p)
 586 {
 587         if (p) put_page(p);
 588 }
 589
 590 extern int register_md_personality(struct md_personality *p);
 591 extern int unregister_md_personality(struct md_personality *p);
 592 extern struct md_thread *md_register_thread(
 593         void (*run)(struct md_thread *thread),
 594         struct mddev *mddev,
 595         const char *name);
 596 extern void md_unregister_thread(struct md_thread **threadp);
 597 extern void md_wakeup_thread(struct md_thread *thread);
 598 extern void md_check_recovery(struct mddev *mddev);
 599 extern void md_reap_sync_thread(struct mddev *mddev);
 600 extern void md_write_start(struct mddev *mddev, struct bio *bi);
 601 extern void md_write_end(struct mddev *mddev);
 602 extern void md_done_sync(struct mddev *mddev, int blocks, int ok);
 603 extern void md_error(struct mddev *mddev, struct md_rdev *rdev);
 604 extern void md_finish_reshape(struct mddev *mddev);
 605
 606 extern int mddev_congested(struct mddev *mddev, int bits);
 607 extern void md_flush_request(struct mddev *mddev, struct bio *bio);
 608 extern void md_super_write(struct mddev *mddev, struct md_rdev *rdev,
 609                            sector_t sector, int size, struct page *page);
 610 extern void md_super_wait(struct mddev *mddev);
 611 extern int sync_page_io(struct md_rdev *rdev, sector_t sector, int size,
 612                         struct page *page, int rw, bool metadata_op);
 613 extern void md_do_sync(struct md_thread *thread);
 614 extern void md_new_event(struct mddev *mddev);
 615 extern int md_allow_write(struct mddev *mddev);
 616 extern void md_wait_for_blocked_rdev(struct md_rdev *rdev, struct mddev *mddev);
 617 extern void md_set_array_sectors(struct mddev *mddev, sector_t array_sectors);
 618 extern int md_check_no_bitmap(struct mddev *mddev);
 619 extern int md_integrity_register(struct mddev *mddev);
 620 extern void md_integrity_add_rdev(struct md_rdev *rdev, struct mddev *mddev);
 621 extern int strict_strtoul_scaled(const char *cp, unsigned long *res, int scale);
 622
 623 extern void mddev_init(struct mddev *mddev);
 624 extern int md_run(struct mddev *mddev);
 625 extern void md_stop(struct mddev *mddev);
 626 extern void md_stop_writes(struct mddev *mddev);
 627 extern int md_rdev_init(struct md_rdev *rdev);
 628 extern void md_rdev_clear(struct md_rdev *rdev);
 629
 630 extern void mddev_suspend(struct mddev *mddev);
 631 extern void mddev_resume(struct mddev *mddev);
 632 extern struct bio *bio_clone_mddev(struct bio *bio, gfp_t gfp_mask,
 633                                    struct mddev *mddev);
 634 extern struct bio *bio_alloc_mddev(gfp_t gfp_mask, int nr_iovecs,
 635                                    struct mddev *mddev);
 636
 637 extern void md_unplug(struct blk_plug_cb *cb, bool from_schedule);
 638 static inline int mddev_check_plugged(struct mddev *mddev)
 639 {
 640         return !!blk_check_plugged(md_unplug, mddev,
 641                                    sizeof(struct blk_plug_cb));
 642 }
 643 #endif /* _MD_MD_H */