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/backing-dev.h>
  20 #include <linux/badblocks.h>
  21 #include <linux/kobject.h>
  22 #include <linux/list.h>
  23 #include <linux/mm.h>
  24 #include <linux/mutex.h>
  25 #include <linux/timer.h>
  26 #include <linux/wait.h>
  27 #include <linux/workqueue.h>
  28 #include "md-cluster.h"
  29
  30 #define MaxSector (~(sector_t)0)
  31
  32 /*
  33  * MD's 'extended' device
  34  */
  35 struct md_rdev {
  36         struct list_head same_set;      /* RAID devices within the same set */
  37
  38         sector_t sectors;               /* Device size (in 512bytes sectors) */
  39         struct mddev *mddev;            /* RAID array if running */
  40         int last_events;                /* IO event timestamp */
  41
  42         /*
  43          * If meta_bdev is non-NULL, it means that a separate device is
  44          * being used to store the metadata (superblock/bitmap) which
  45          * would otherwise be contained on the same device as the data (bdev).
  46          */
  47         struct block_device *meta_bdev;
  48         struct block_device *bdev;      /* block device handle */
  49
  50         struct page     *sb_page, *bb_page;
  51         int             sb_loaded;
  52         __u64           sb_events;
  53         sector_t        data_offset;    /* start of data in array */
  54         sector_t        new_data_offset;/* only relevant while reshaping */
  55         sector_t        sb_start;       /* offset of the super block (in 512byte sectors) */
  56         int             sb_size;        /* bytes in the superblock */
  57         int             preferred_minor;        /* autorun support */
  58
  59         struct kobject  kobj;
  60
  61         /* A device can be in one of three states based on two flags:
  62          * Not working:   faulty==1 in_sync==0
  63          * Fully working: faulty==0 in_sync==1
  64          * Working, but not
  65          * in sync with array
  66          *                faulty==0 in_sync==0
  67          *
  68          * It can never have faulty==1, in_sync==1
  69          * This reduces the burden of testing multiple flags in many cases
  70          */
  71
  72         unsigned long   flags;  /* bit set of 'enum flag_bits' bits. */
  73         wait_queue_head_t blocked_wait;
  74
  75         int desc_nr;                    /* descriptor index in the superblock */
  76         int raid_disk;                  /* role of device in array */
  77         int new_raid_disk;              /* role that the device will have in
  78                                          * the array after a level-change completes.
  79                                          */
  80         int saved_raid_disk;            /* role that device used to have in the
  81                                          * array and could again if we did a partial
  82                                          * resync from the bitmap
  83                                          */
  84         union {
  85                 sector_t recovery_offset;/* If this device has been partially
  86                                          * recovered, this is where we were
  87                                          * up to.
  88                                          */
  89                 sector_t journal_tail;  /* If this device is a journal device,
  90                                          * this is the journal tail (journal
  91                                          * recovery start point)
  92                                          */
  93         };
  94
  95         atomic_t        nr_pending;     /* number of pending requests.
  96                                          * only maintained for arrays that
  97                                          * support hot removal
  98                                          */
  99         atomic_t        read_errors;    /* number of consecutive read errors that
 100                                          * we have tried to ignore.
 101                                          */
 102         struct timespec last_read_error;        /* monotonic time since our
 103                                                  * last read error
 104                                                  */
 105         atomic_t        corrected_errors; /* number of corrected read errors,
 106                                            * for reporting to userspace and storing
 107                                            * in superblock.
 108                                            */
 109         struct work_struct del_work;    /* used for delayed sysfs removal */
 110
 111         struct kernfs_node *sysfs_state; /* handle for 'state'
 112                                            * sysfs entry */
 113
 114         struct badblocks badblocks;
 115 };
 116 enum flag_bits {
 117         Faulty,                 /* device is known to have a fault */
 118         In_sync,                /* device is in_sync with rest of array */
 119         Bitmap_sync,            /* ..actually, not quite In_sync.  Need a
 120                                  * bitmap-based recovery to get fully in sync
 121                                  */
 122         WriteMostly,            /* Avoid reading if at all possible */
 123         AutoDetected,           /* added by auto-detect */
 124         Blocked,                /* An error occurred but has not yet
 125                                  * been acknowledged by the metadata
 126                                  * handler, so don't allow writes
 127                                  * until it is cleared */
 128         WriteErrorSeen,         /* A write error has been seen on this
 129                                  * device
 130                                  */
 131         FaultRecorded,          /* Intermediate state for clearing
 132                                  * Blocked.  The Fault is/will-be
 133                                  * recorded in the metadata, but that
 134                                  * metadata hasn't been stored safely
 135                                  * on disk yet.
 136                                  */
 137         BlockedBadBlocks,       /* A writer is blocked because they
 138                                  * found an unacknowledged bad-block.
 139                                  * This can safely be cleared at any
 140                                  * time, and the writer will re-check.
 141                                  * It may be set at any time, and at
 142                                  * worst the writer will timeout and
 143                                  * re-check.  So setting it as
 144                                  * accurately as possible is good, but
 145                                  * not absolutely critical.
 146                                  */
 147         WantReplacement,        /* This device is a candidate to be
 148                                  * hot-replaced, either because it has
 149                                  * reported some faults, or because
 150                                  * of explicit request.
 151                                  */
 152         Replacement,            /* This device is a replacement for
 153                                  * a want_replacement device with same
 154                                  * raid_disk number.
 155                                  */
 156         Candidate,              /* For clustered environments only:
 157                                  * This device is seen locally but not
 158                                  * by the whole cluster
 159                                  */
 160         Journal,                /* This device is used as journal for
 161                                  * raid-5/6.
 162                                  * Usually, this device should be faster
 163                                  * than other devices in the array
 164                                  */
 165 };
 166
 167 static inline int is_badblock(struct md_rdev *rdev, sector_t s, int sectors,
 168                               sector_t *first_bad, int *bad_sectors)
 169 {
 170         if (unlikely(rdev->badblocks.count)) {
 171                 int rv = badblocks_check(&rdev->badblocks, rdev->data_offset + s,
 172                                         sectors,
 173                                         first_bad, bad_sectors);
 174                 if (rv)
 175                         *first_bad -= rdev->data_offset;
 176                 return rv;
 177         }
 178         return 0;
 179 }
 180 extern int rdev_set_badblocks(struct md_rdev *rdev, sector_t s, int sectors,
 181                               int is_new);
 182 extern int rdev_clear_badblocks(struct md_rdev *rdev, sector_t s, int sectors,
 183                                 int is_new);
 184 struct md_cluster_info;
 185
 186 struct mddev {
 187         void                            *private;
 188         struct md_personality           *pers;
 189         dev_t                           unit;
 190         int                             md_minor;
 191         struct list_head                disks;
 192         unsigned long                   flags;
 193 #define MD_CHANGE_DEVS  0       /* Some device status has changed */
 194 #define MD_CHANGE_CLEAN 1       /* transition to or from 'clean' */
 195 #define MD_CHANGE_PENDING 2     /* switch from 'clean' to 'active' in progress */
 196 #define MD_UPDATE_SB_FLAGS (1 | 2 | 4)  /* If these are set, md_update_sb needed */
 197 #define MD_ARRAY_FIRST_USE 3    /* First use of array, needs initialization */
 198 #define MD_STILL_CLOSED 4       /* If set, then array has not been opened since
 199                                  * md_ioctl checked on it.
 200                                  */
 201 #define MD_JOURNAL_CLEAN 5      /* A raid with journal is already clean */
 202 #define MD_HAS_JOURNAL  6       /* The raid array has journal feature set */
 203
 204         int                             suspended;
 205         atomic_t                        active_io;
 206         int                             ro;
 207         int                             sysfs_active; /* set when sysfs deletes
 208                                                        * are happening, so run/
 209                                                        * takeover/stop are not safe
 210                                                        */
 211         int                             ready; /* See when safe to pass
 212                                                 * IO requests down */
 213         struct gendisk                  *gendisk;
 214
 215         struct kobject                  kobj;
 216         int                             hold_active;
 217 #define UNTIL_IOCTL     1
 218 #define UNTIL_STOP      2
 219
 220         /* Superblock information */
 221         int                             major_version,
 222                                         minor_version,
 223                                         patch_version;
 224         int                             persistent;
 225         int                             external;       /* metadata is
 226                                                          * managed externally */
 227         char                            metadata_type[17]; /* externally set*/
 228         int                             chunk_sectors;
 229         time_t                          ctime, utime;
 230         int                             level, layout;
 231         char                            clevel[16];
 232         int                             raid_disks;
 233         int                             max_disks;
 234         sector_t                        dev_sectors;    /* used size of
 235                                                          * component devices */
 236         sector_t                        array_sectors; /* exported array size */
 237         int                             external_size; /* size managed
 238                                                         * externally */
 239         __u64                           events;
 240         /* If the last 'event' was simply a clean->dirty transition, and
 241          * we didn't write it to the spares, then it is safe and simple
 242          * to just decrement the event count on a dirty->clean transition.
 243          * So we record that possibility here.
 244          */
 245         int                             can_decrease_events;
 246
 247         char                            uuid[16];
 248
 249         /* If the array is being reshaped, we need to record the
 250          * new shape and an indication of where we are up to.
 251          * This is written to the superblock.
 252          * If reshape_position is MaxSector, then no reshape is happening (yet).
 253          */
 254         sector_t                        reshape_position;
 255         int                             delta_disks, new_level, new_layout;
 256         int                             new_chunk_sectors;
 257         int                             reshape_backwards;
 258
 259         struct md_thread                *thread;        /* management thread */
 260         struct md_thread                *sync_thread;   /* doing resync or reconstruct */
 261
 262         /* 'last_sync_action' is initialized to "none".  It is set when a
 263          * sync operation (i.e "data-check", "requested-resync", "resync",
 264          * "recovery", or "reshape") is started.  It holds this value even
 265          * when the sync thread is "frozen" (interrupted) or "idle" (stopped
 266          * or finished).  It is overwritten when a new sync operation is begun.
 267          */
 268         char                            *last_sync_action;
 269         sector_t                        curr_resync;    /* last block scheduled */
 270         /* As resync requests can complete out of order, we cannot easily track
 271          * how much resync has been completed.  So we occasionally pause until
 272          * everything completes, then set curr_resync_completed to curr_resync.
 273          * As such it may be well behind the real resync mark, but it is a value
 274          * we are certain of.
 275          */
 276         sector_t                        curr_resync_completed;
 277         unsigned long                   resync_mark;    /* a recent timestamp */
 278         sector_t                        resync_mark_cnt;/* blocks written at resync_mark */
 279         sector_t                        curr_mark_cnt; /* blocks scheduled now */
 280
 281         sector_t                        resync_max_sectors; /* may be set by personality */
 282
 283         atomic64_t                      resync_mismatches; /* count of sectors where
 284                                                             * parity/replica mismatch found
 285                                                             */
 286
 287         /* allow user-space to request suspension of IO to regions of the array */
 288         sector_t                        suspend_lo;
 289         sector_t                        suspend_hi;
 290         /* if zero, use the system-wide default */
 291         int                             sync_speed_min;
 292         int                             sync_speed_max;
 293
 294         /* resync even though the same disks are shared among md-devices */
 295         int                             parallel_resync;
 296
 297         int                             ok_start_degraded;
 298         /* recovery/resync flags
 299          * NEEDED:   we might need to start a resync/recover
 300          * RUNNING:  a thread is running, or about to be started
 301          * SYNC:     actually doing a resync, not a recovery
 302          * RECOVER:  doing recovery, or need to try it.
 303          * INTR:     resync needs to be aborted for some reason
 304          * DONE:     thread is done and is waiting to be reaped
 305          * REQUEST:  user-space has requested a sync (used with SYNC)
 306          * CHECK:    user-space request for check-only, no repair
 307          * RESHAPE:  A reshape is happening
 308          * ERROR:    sync-action interrupted because io-error
 309          *
 310          * If neither SYNC or RESHAPE are set, then it is a recovery.
 311          */
 312 #define MD_RECOVERY_RUNNING     0
 313 #define MD_RECOVERY_SYNC        1
 314 #define MD_RECOVERY_RECOVER     2
 315 #define MD_RECOVERY_INTR        3
 316 #define MD_RECOVERY_DONE        4
 317 #define MD_RECOVERY_NEEDED      5
 318 #define MD_RECOVERY_REQUESTED   6
 319 #define MD_RECOVERY_CHECK       7
 320 #define MD_RECOVERY_RESHAPE     8
 321 #define MD_RECOVERY_FROZEN      9
 322 #define MD_RECOVERY_ERROR       10
 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
 353         atomic_t                        recovery_active; /* blocks scheduled, but not written */
 354         wait_queue_head_t               recovery_wait;
 355         sector_t                        recovery_cp;
 356         sector_t                        resync_min;     /* user requested sync
 357                                                          * starts here */
 358         sector_t                        resync_max;     /* resync should pause
 359                                                          * when it gets here */
 360
 361         struct kernfs_node              *sysfs_state;   /* handle for 'array_state'
 362                                                          * file in sysfs.
 363                                                          */
 364         struct kernfs_node              *sysfs_action;  /* handle for 'sync_action' */
 365
 366         struct work_struct del_work;    /* used for delayed sysfs removal */
 367
 368         /* "lock" protects:
 369          *   flush_bio transition from NULL to !NULL
 370          *   rdev superblocks, events
 371          *   clearing MD_CHANGE_*
 372          *   in_sync - and related safemode and MD_CHANGE changes
 373          *   pers (also protected by reconfig_mutex and pending IO).
 374          *   clearing ->bitmap
 375          *   clearing ->bitmap_info.file
 376          *   changing ->resync_{min,max}
 377          *   setting MD_RECOVERY_RUNNING (which interacts with resync_{min,max})
 378          */
 379         spinlock_t                      lock;
 380         wait_queue_head_t               sb_wait;        /* for waiting on superblock updates */
 381         atomic_t                        pending_writes; /* number of active superblock writes */
 382
 383         unsigned int                    safemode;       /* if set, update "clean" superblock
 384                                                          * when no writes pending.
 385                                                          */
 386         unsigned int                    safemode_delay;
 387         struct timer_list               safemode_timer;
 388         atomic_t                        writes_pending;
 389         struct request_queue            *queue; /* for plugging ... */
 390
 391         struct bitmap                   *bitmap; /* the bitmap for the device */
 392         struct {
 393                 struct file             *file; /* the bitmap file */
 394                 loff_t                  offset; /* offset from superblock of
 395                                                  * start of bitmap. May be
 396                                                  * negative, but not '0'
 397                                                  * For external metadata, offset
 398                                                  * from start of device.
 399                                                  */
 400                 unsigned long           space; /* space available at this offset */
 401                 loff_t                  default_offset; /* this is the offset to use when
 402                                                          * hot-adding a bitmap.  It should
 403                                                          * eventually be settable by sysfs.
 404                                                          */
 405                 unsigned long           default_space; /* space available at
 406                                                         * default offset */
 407                 struct mutex            mutex;
 408                 unsigned long           chunksize;
 409                 unsigned long           daemon_sleep; /* how many jiffies between updates? */
 410                 unsigned long           max_write_behind; /* write-behind mode */
 411                 int                     external;
 412                 int                     nodes; /* Maximum number of nodes in the cluster */
 413                 char                    cluster_name[64]; /* Name of the cluster */
 414         } bitmap_info;
 415
 416         atomic_t                        max_corr_read_errors; /* max read retries */
 417         struct list_head                all_mddevs;
 418
 419         struct attribute_group          *to_remove;
 420
 421         struct bio_set                  *bio_set;
 422
 423         /* Generic flush handling.
 424          * The last to finish preflush schedules a worker to submit
 425          * the rest of the request (without the REQ_FLUSH flag).
 426          */
 427         struct bio *flush_bio;
 428         atomic_t flush_pending;
 429         struct work_struct flush_work;
 430         struct work_struct event_work;  /* used by dm to report failure event */
 431         void (*sync_super)(struct mddev *mddev, struct md_rdev *rdev);
 432         struct md_cluster_info          *cluster_info;
 433 };
 434
 435 static inline int __must_check mddev_lock(struct mddev *mddev)
 436 {
 437         return mutex_lock_interruptible(&mddev->reconfig_mutex);
 438 }
 439
 440 /* Sometimes we need to take the lock in a situation where
 441  * failure due to interrupts is not acceptable.
 442  */
 443 static inline void mddev_lock_nointr(struct mddev *mddev)
 444 {
 445         mutex_lock(&mddev->reconfig_mutex);
 446 }
 447
 448 static inline int mddev_is_locked(struct mddev *mddev)
 449 {
 450         return mutex_is_locked(&mddev->reconfig_mutex);
 451 }
 452
 453 static inline int mddev_trylock(struct mddev *mddev)
 454 {
 455         return mutex_trylock(&mddev->reconfig_mutex);
 456 }
 457 extern void mddev_unlock(struct mddev *mddev);
 458
 459 static inline void md_sync_acct(struct block_device *bdev, unsigned long nr_sectors)
 460 {
 461         atomic_add(nr_sectors, &bdev->bd_contains->bd_disk->sync_io);
 462 }
 463
 464 struct md_personality
 465 {
 466         char *name;
 467         int level;
 468         struct list_head list;
 469         struct module *owner;
 470         void (*make_request)(struct mddev *mddev, struct bio *bio);
 471         int (*run)(struct mddev *mddev);
 472         void (*free)(struct mddev *mddev, void *priv);
 473         void (*status)(struct seq_file *seq, struct mddev *mddev);
 474         /* error_handler must set ->faulty and clear ->in_sync
 475          * if appropriate, and should abort recovery if needed
 476          */
 477         void (*error_handler)(struct mddev *mddev, struct md_rdev *rdev);
 478         int (*hot_add_disk) (struct mddev *mddev, struct md_rdev *rdev);
 479         int (*hot_remove_disk) (struct mddev *mddev, struct md_rdev *rdev);
 480         int (*spare_active) (struct mddev *mddev);
 481         sector_t (*sync_request)(struct mddev *mddev, sector_t sector_nr, int *skipped);
 482         int (*resize) (struct mddev *mddev, sector_t sectors);
 483         sector_t (*size) (struct mddev *mddev, sector_t sectors, int raid_disks);
 484         int (*check_reshape) (struct mddev *mddev);
 485         int (*start_reshape) (struct mddev *mddev);
 486         void (*finish_reshape) (struct mddev *mddev);
 487         /* quiesce moves between quiescence states
 488          * 0 - fully active
 489          * 1 - no new requests allowed
 490          * others - reserved
 491          */
 492         void (*quiesce) (struct mddev *mddev, int state);
 493         /* takeover is used to transition an array from one
 494          * personality to another.  The new personality must be able
 495          * to handle the data in the current layout.
 496          * e.g. 2drive raid1 -> 2drive raid5
 497          *      ndrive raid5 -> degraded n+1drive raid6 with special layout
 498          * If the takeover succeeds, a new 'private' structure is returned.
 499          * This needs to be installed and then ->run used to activate the
 500          * array.
 501          */
 502         void *(*takeover) (struct mddev *mddev);
 503         /* congested implements bdi.congested_fn().
 504          * Will not be called while array is 'suspended' */
 505         int (*congested)(struct mddev *mddev, int bits);
 506 };
 507
 508 struct md_sysfs_entry {
 509         struct attribute attr;
 510         ssize_t (*show)(struct mddev *, char *);
 511         ssize_t (*store)(struct mddev *, const char *, size_t);
 512 };
 513 extern struct attribute_group md_bitmap_group;
 514
 515 static inline struct kernfs_node *sysfs_get_dirent_safe(struct kernfs_node *sd, char *name)
 516 {
 517         if (sd)
 518                 return sysfs_get_dirent(sd, name);
 519         return sd;
 520 }
 521 static inline void sysfs_notify_dirent_safe(struct kernfs_node *sd)
 522 {
 523         if (sd)
 524                 sysfs_notify_dirent(sd);
 525 }
 526
 527 static inline char * mdname (struct mddev * mddev)
 528 {
 529         return mddev->gendisk ? mddev->gendisk->disk_name : "mdX";
 530 }
 531
 532 static inline int sysfs_link_rdev(struct mddev *mddev, struct md_rdev *rdev)
 533 {
 534         char nm[20];
 535         if (!test_bit(Replacement, &rdev->flags) &&
 536             !test_bit(Journal, &rdev->flags) &&
 537             mddev->kobj.sd) {
 538                 sprintf(nm, "rd%d", rdev->raid_disk);
 539                 return sysfs_create_link(&mddev->kobj, &rdev->kobj, nm);
 540         } else
 541                 return 0;
 542 }
 543
 544 static inline void sysfs_unlink_rdev(struct mddev *mddev, struct md_rdev *rdev)
 545 {
 546         char nm[20];
 547         if (!test_bit(Replacement, &rdev->flags) &&
 548             !test_bit(Journal, &rdev->flags) &&
 549             mddev->kobj.sd) {
 550                 sprintf(nm, "rd%d", rdev->raid_disk);
 551                 sysfs_remove_link(&mddev->kobj, nm);
 552         }
 553 }
 554
 555 /*
 556  * iterates through some rdev ringlist. It's safe to remove the
 557  * current 'rdev'. Dont touch 'tmp' though.
 558  */
 559 #define rdev_for_each_list(rdev, tmp, head)                             \
 560         list_for_each_entry_safe(rdev, tmp, head, same_set)
 561
 562 /*
 563  * iterates through the 'same array disks' ringlist
 564  */
 565 #define rdev_for_each(rdev, mddev)                              \
 566         list_for_each_entry(rdev, &((mddev)->disks), same_set)
 567
 568 #define rdev_for_each_safe(rdev, tmp, mddev)                            \
 569         list_for_each_entry_safe(rdev, tmp, &((mddev)->disks), same_set)
 570
 571 #define rdev_for_each_rcu(rdev, mddev)                          \
 572         list_for_each_entry_rcu(rdev, &((mddev)->disks), same_set)
 573
 574 struct md_thread {
 575         void                    (*run) (struct md_thread *thread);
 576         struct mddev            *mddev;
 577         wait_queue_head_t       wqueue;
 578         unsigned long           flags;
 579         struct task_struct      *tsk;
 580         unsigned long           timeout;
 581         void                    *private;
 582 };
 583
 584 #define THREAD_WAKEUP  0
 585
 586 static inline void safe_put_page(struct page *p)
 587 {
 588         if (p) put_page(p);
 589 }
 590
 591 extern int register_md_personality(struct md_personality *p);
 592 extern int unregister_md_personality(struct md_personality *p);
 593 extern int register_md_cluster_operations(struct md_cluster_operations *ops,
 594                 struct module *module);
 595 extern int unregister_md_cluster_operations(void);
 596 extern int md_setup_cluster(struct mddev *mddev, int nodes);
 597 extern void md_cluster_stop(struct mddev *mddev);
 598 extern struct md_thread *md_register_thread(
 599         void (*run)(struct md_thread *thread),
 600         struct mddev *mddev,
 601         const char *name);
 602 extern void md_unregister_thread(struct md_thread **threadp);
 603 extern void md_wakeup_thread(struct md_thread *thread);
 604 extern void md_check_recovery(struct mddev *mddev);
 605 extern void md_reap_sync_thread(struct mddev *mddev);
 606 extern void md_write_start(struct mddev *mddev, struct bio *bi);
 607 extern void md_write_end(struct mddev *mddev);
 608 extern void md_done_sync(struct mddev *mddev, int blocks, int ok);
 609 extern void md_error(struct mddev *mddev, struct md_rdev *rdev);
 610 extern void md_finish_reshape(struct mddev *mddev);
 611
 612 extern int mddev_congested(struct mddev *mddev, int bits);
 613 extern void md_flush_request(struct mddev *mddev, struct bio *bio);
 614 extern void md_super_write(struct mddev *mddev, struct md_rdev *rdev,
 615                            sector_t sector, int size, struct page *page);
 616 extern void md_super_wait(struct mddev *mddev);
 617 extern int sync_page_io(struct md_rdev *rdev, sector_t sector, int size,
 618                         struct page *page, int rw, bool metadata_op);
 619 extern void md_do_sync(struct md_thread *thread);
 620 extern void md_new_event(struct mddev *mddev);
 621 extern int md_allow_write(struct mddev *mddev);
 622 extern void md_wait_for_blocked_rdev(struct md_rdev *rdev, struct mddev *mddev);
 623 extern void md_set_array_sectors(struct mddev *mddev, sector_t array_sectors);
 624 extern int md_check_no_bitmap(struct mddev *mddev);
 625 extern int md_integrity_register(struct mddev *mddev);
 626 extern void md_integrity_add_rdev(struct md_rdev *rdev, struct mddev *mddev);
 627 extern int strict_strtoul_scaled(const char *cp, unsigned long *res, int scale);
 628
 629 extern void mddev_init(struct mddev *mddev);
 630 extern int md_run(struct mddev *mddev);
 631 extern void md_stop(struct mddev *mddev);
 632 extern void md_stop_writes(struct mddev *mddev);
 633 extern int md_rdev_init(struct md_rdev *rdev);
 634 extern void md_rdev_clear(struct md_rdev *rdev);
 635
 636 extern void mddev_suspend(struct mddev *mddev);
 637 extern void mddev_resume(struct mddev *mddev);
 638 extern struct bio *bio_clone_mddev(struct bio *bio, gfp_t gfp_mask,
 639                                    struct mddev *mddev);
 640 extern struct bio *bio_alloc_mddev(gfp_t gfp_mask, int nr_iovecs,
 641                                    struct mddev *mddev);
 642
 643 extern void md_unplug(struct blk_plug_cb *cb, bool from_schedule);
 644 extern void md_reload_sb(struct mddev *mddev, int raid_disk);
 645 extern void md_update_sb(struct mddev *mddev, int force);
 646 extern void md_kick_rdev_from_array(struct md_rdev * rdev);
 647 struct md_rdev *md_find_rdev_nr_rcu(struct mddev *mddev, int nr);
 648 static inline int mddev_check_plugged(struct mddev *mddev)
 649 {
 650         return !!blk_check_plugged(md_unplug, mddev,
 651                                    sizeof(struct blk_plug_cb));
 652 }
 653
 654 static inline void rdev_dec_pending(struct md_rdev *rdev, struct mddev *mddev)
 655 {
 656         int faulty = test_bit(Faulty, &rdev->flags);
 657         if (atomic_dec_and_test(&rdev->nr_pending) && faulty) {
 658                 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
 659                 md_wakeup_thread(mddev->thread);
 660         }
 661 }
 662
 663 extern struct md_cluster_operations *md_cluster_ops;
 664 static inline int mddev_is_clustered(struct mddev *mddev)
 665 {
 666         return mddev->cluster_info && mddev->bitmap_info.nodes > 1;
 667 }
 668 #endif /* _MD_MD_H */