drivers/md/md.h

   1 /* SPDX-License-Identifier: GPL-2.0-or-later */
   2 /*
   3    md.h : kernel internal structure of the Linux MD driver
   4           Copyright (C) 1996-98 Ingo Molnar, Gadi Oxman
   5
   6 */
   7
   8 #ifndef _MD_MD_H
   9 #define _MD_MD_H
  10
  11 #include <linux/blkdev.h>
  12 #include <linux/backing-dev.h>
  13 #include <linux/badblocks.h>
  14 #include <linux/kobject.h>
  15 #include <linux/list.h>
  16 #include <linux/mm.h>
  17 #include <linux/mutex.h>
  18 #include <linux/timer.h>
  19 #include <linux/wait.h>
  20 #include <linux/workqueue.h>
  21 #include "md-cluster.h"
  22
  23 #define MaxSector (~(sector_t)0)
  24
  25 /*
  26  * These flags should really be called "NO_RETRY" rather than
  27  * "FAILFAST" because they don't make any promise about time lapse,
  28  * only about the number of retries, which will be zero.
  29  * REQ_FAILFAST_DRIVER is not included because
  30  * Commit: 4a27446f3e39 ("[SCSI] modify scsi to handle new fail fast flags.")
  31  * seems to suggest that the errors it avoids retrying should usually
  32  * be retried.
  33  */
  34 #define MD_FAILFAST     (REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT)
  35
  36 /*
  37  * The struct embedded in rdev is used to serialize IO.
  38  */
  39 struct serial_in_rdev {
  40         struct rb_root_cached serial_rb;
  41         spinlock_t serial_lock;
  42         wait_queue_head_t serial_io_wait;
  43 };
  44
  45 /*
  46  * MD's 'extended' device
  47  */
  48 struct md_rdev {
  49         struct list_head same_set;      /* RAID devices within the same set */
  50
  51         sector_t sectors;               /* Device size (in 512bytes sectors) */
  52         struct mddev *mddev;            /* RAID array if running */
  53         int last_events;                /* IO event timestamp */
  54
  55         /*
  56          * If meta_bdev is non-NULL, it means that a separate device is
  57          * being used to store the metadata (superblock/bitmap) which
  58          * would otherwise be contained on the same device as the data (bdev).
  59          */
  60         struct block_device *meta_bdev;
  61         struct block_device *bdev;      /* block device handle */
  62
  63         struct page     *sb_page, *bb_page;
  64         int             sb_loaded;
  65         __u64           sb_events;
  66         sector_t        data_offset;    /* start of data in array */
  67         sector_t        new_data_offset;/* only relevant while reshaping */
  68         sector_t        sb_start;       /* offset of the super block (in 512byte sectors) */
  69         int             sb_size;        /* bytes in the superblock */
  70         int             preferred_minor;        /* autorun support */
  71
  72         struct kobject  kobj;
  73
  74         /* A device can be in one of three states based on two flags:
  75          * Not working:   faulty==1 in_sync==0
  76          * Fully working: faulty==0 in_sync==1
  77          * Working, but not
  78          * in sync with array
  79          *                faulty==0 in_sync==0
  80          *
  81          * It can never have faulty==1, in_sync==1
  82          * This reduces the burden of testing multiple flags in many cases
  83          */
  84
  85         unsigned long   flags;  /* bit set of 'enum flag_bits' bits. */
  86         wait_queue_head_t blocked_wait;
  87
  88         int desc_nr;                    /* descriptor index in the superblock */
  89         int raid_disk;                  /* role of device in array */
  90         int new_raid_disk;              /* role that the device will have in
  91                                          * the array after a level-change completes.
  92                                          */
  93         int saved_raid_disk;            /* role that device used to have in the
  94                                          * array and could again if we did a partial
  95                                          * resync from the bitmap
  96                                          */
  97         union {
  98                 sector_t recovery_offset;/* If this device has been partially
  99                                          * recovered, this is where we were
 100                                          * up to.
 101                                          */
 102                 sector_t journal_tail;  /* If this device is a journal device,
 103                                          * this is the journal tail (journal
 104                                          * recovery start point)
 105                                          */
 106         };
 107
 108         atomic_t        nr_pending;     /* number of pending requests.
 109                                          * only maintained for arrays that
 110                                          * support hot removal
 111                                          */
 112         atomic_t        read_errors;    /* number of consecutive read errors that
 113                                          * we have tried to ignore.
 114                                          */
 115         time64_t        last_read_error;        /* monotonic time since our
 116                                                  * last read error
 117                                                  */
 118         atomic_t        corrected_errors; /* number of corrected read errors,
 119                                            * for reporting to userspace and storing
 120                                            * in superblock.
 121                                            */
 122
 123         struct serial_in_rdev *serial;  /* used for raid1 io serialization */
 124
 125         struct work_struct del_work;    /* used for delayed sysfs removal */
 126
 127         struct kernfs_node *sysfs_state; /* handle for 'state'
 128                                            * sysfs entry */
 129         /* handle for 'unacknowledged_bad_blocks' sysfs dentry */
 130         struct kernfs_node *sysfs_unack_badblocks;
 131         /* handle for 'bad_blocks' sysfs dentry */
 132         struct kernfs_node *sysfs_badblocks;
 133         struct badblocks badblocks;
 134
 135         struct {
 136                 short offset;   /* Offset from superblock to start of PPL.
 137                                  * Not used by external metadata. */
 138                 unsigned int size;      /* Size in sectors of the PPL space */
 139                 sector_t sector;        /* First sector of the PPL space */
 140         } ppl;
 141 };
 142 enum flag_bits {
 143         Faulty,                 /* device is known to have a fault */
 144         In_sync,                /* device is in_sync with rest of array */
 145         Bitmap_sync,            /* ..actually, not quite In_sync.  Need a
 146                                  * bitmap-based recovery to get fully in sync.
 147                                  * The bit is only meaningful before device
 148                                  * has been passed to pers->hot_add_disk.
 149                                  */
 150         WriteMostly,            /* Avoid reading if at all possible */
 151         AutoDetected,           /* added by auto-detect */
 152         Blocked,                /* An error occurred but has not yet
 153                                  * been acknowledged by the metadata
 154                                  * handler, so don't allow writes
 155                                  * until it is cleared */
 156         WriteErrorSeen,         /* A write error has been seen on this
 157                                  * device
 158                                  */
 159         FaultRecorded,          /* Intermediate state for clearing
 160                                  * Blocked.  The Fault is/will-be
 161                                  * recorded in the metadata, but that
 162                                  * metadata hasn't been stored safely
 163                                  * on disk yet.
 164                                  */
 165         BlockedBadBlocks,       /* A writer is blocked because they
 166                                  * found an unacknowledged bad-block.
 167                                  * This can safely be cleared at any
 168                                  * time, and the writer will re-check.
 169                                  * It may be set at any time, and at
 170                                  * worst the writer will timeout and
 171                                  * re-check.  So setting it as
 172                                  * accurately as possible is good, but
 173                                  * not absolutely critical.
 174                                  */
 175         WantReplacement,        /* This device is a candidate to be
 176                                  * hot-replaced, either because it has
 177                                  * reported some faults, or because
 178                                  * of explicit request.
 179                                  */
 180         Replacement,            /* This device is a replacement for
 181                                  * a want_replacement device with same
 182                                  * raid_disk number.
 183                                  */
 184         Candidate,              /* For clustered environments only:
 185                                  * This device is seen locally but not
 186                                  * by the whole cluster
 187                                  */
 188         Journal,                /* This device is used as journal for
 189                                  * raid-5/6.
 190                                  * Usually, this device should be faster
 191                                  * than other devices in the array
 192                                  */
 193         ClusterRemove,
 194         RemoveSynchronized,     /* synchronize_rcu() was called after
 195                                  * this device was known to be faulty,
 196                                  * so it is safe to remove without
 197                                  * another synchronize_rcu() call.
 198                                  */
 199         ExternalBbl,            /* External metadata provides bad
 200                                  * block management for a disk
 201                                  */
 202         FailFast,               /* Minimal retries should be attempted on
 203                                  * this device, so use REQ_FAILFAST_DEV.
 204                                  * Also don't try to repair failed reads.
 205                                  * It is expects that no bad block log
 206                                  * is present.
 207                                  */
 208         LastDev,                /* Seems to be the last working dev as
 209                                  * it didn't fail, so don't use FailFast
 210                                  * any more for metadata
 211                                  */
 212         CollisionCheck,         /*
 213                                  * check if there is collision between raid1
 214                                  * serial bios.
 215                                  */
 216 };
 217
 218 static inline int is_badblock(struct md_rdev *rdev, sector_t s, int sectors,
 219                               sector_t *first_bad, int *bad_sectors)
 220 {
 221         if (unlikely(rdev->badblocks.count)) {
 222                 int rv = badblocks_check(&rdev->badblocks, rdev->data_offset + s,
 223                                         sectors,
 224                                         first_bad, bad_sectors);
 225                 if (rv)
 226                         *first_bad -= rdev->data_offset;
 227                 return rv;
 228         }
 229         return 0;
 230 }
 231 extern int rdev_set_badblocks(struct md_rdev *rdev, sector_t s, int sectors,
 232                               int is_new);
 233 extern int rdev_clear_badblocks(struct md_rdev *rdev, sector_t s, int sectors,
 234                                 int is_new);
 235 struct md_cluster_info;
 236
 237 /* change UNSUPPORTED_MDDEV_FLAGS for each array type if new flag is added */
 238 enum mddev_flags {
 239         MD_ARRAY_FIRST_USE,     /* First use of array, needs initialization */
 240         MD_CLOSING,             /* If set, we are closing the array, do not open
 241                                  * it then */
 242         MD_JOURNAL_CLEAN,       /* A raid with journal is already clean */
 243         MD_HAS_JOURNAL,         /* The raid array has journal feature set */
 244         MD_CLUSTER_RESYNC_LOCKED, /* cluster raid only, which means node
 245                                    * already took resync lock, need to
 246                                    * release the lock */
 247         MD_FAILFAST_SUPPORTED,  /* Using MD_FAILFAST on metadata writes is
 248                                  * supported as calls to md_error() will
 249                                  * never cause the array to become failed.
 250                                  */
 251         MD_HAS_PPL,             /* The raid array has PPL feature set */
 252         MD_HAS_MULTIPLE_PPLS,   /* The raid array has multiple PPLs feature set */
 253         MD_ALLOW_SB_UPDATE,     /* md_check_recovery is allowed to update
 254                                  * the metadata without taking reconfig_mutex.
 255                                  */
 256         MD_UPDATING_SB,         /* md_check_recovery is updating the metadata
 257                                  * without explicitly holding reconfig_mutex.
 258                                  */
 259         MD_NOT_READY,           /* do_md_run() is active, so 'array_state'
 260                                  * must not report that array is ready yet
 261                                  */
 262         MD_BROKEN,              /* This is used in RAID-0/LINEAR only, to stop
 263                                  * I/O in case an array member is gone/failed.
 264                                  */
 265 };
 266
 267 enum mddev_sb_flags {
 268         MD_SB_CHANGE_DEVS,              /* Some device status has changed */
 269         MD_SB_CHANGE_CLEAN,     /* transition to or from 'clean' */
 270         MD_SB_CHANGE_PENDING,   /* switch from 'clean' to 'active' in progress */
 271         MD_SB_NEED_REWRITE,     /* metadata write needs to be repeated */
 272 };
 273
 274 #define NR_SERIAL_INFOS         8
 275 /* record current range of serialize IOs */
 276 struct serial_info {
 277         struct rb_node node;
 278         sector_t start;         /* start sector of rb node */
 279         sector_t last;          /* end sector of rb node */
 280         sector_t _subtree_last; /* highest sector in subtree of rb node */
 281 };
 282
 283 struct mddev {
 284         void                            *private;
 285         struct md_personality           *pers;
 286         dev_t                           unit;
 287         int                             md_minor;
 288         struct list_head                disks;
 289         unsigned long                   flags;
 290         unsigned long                   sb_flags;
 291
 292         int                             suspended;
 293         atomic_t                        active_io;
 294         int                             ro;
 295         int                             sysfs_active; /* set when sysfs deletes
 296                                                        * are happening, so run/
 297                                                        * takeover/stop are not safe
 298                                                        */
 299         struct gendisk                  *gendisk;
 300
 301         struct kobject                  kobj;
 302         int                             hold_active;
 303 #define UNTIL_IOCTL     1
 304 #define UNTIL_STOP      2
 305
 306         /* Superblock information */
 307         int                             major_version,
 308                                         minor_version,
 309                                         patch_version;
 310         int                             persistent;
 311         int                             external;       /* metadata is
 312                                                          * managed externally */
 313         char                            metadata_type[17]; /* externally set*/
 314         int                             chunk_sectors;
 315         time64_t                        ctime, utime;
 316         int                             level, layout;
 317         char                            clevel[16];
 318         int                             raid_disks;
 319         int                             max_disks;
 320         sector_t                        dev_sectors;    /* used size of
 321                                                          * component devices */
 322         sector_t                        array_sectors; /* exported array size */
 323         int                             external_size; /* size managed
 324                                                         * externally */
 325         __u64                           events;
 326         /* If the last 'event' was simply a clean->dirty transition, and
 327          * we didn't write it to the spares, then it is safe and simple
 328          * to just decrement the event count on a dirty->clean transition.
 329          * So we record that possibility here.
 330          */
 331         int                             can_decrease_events;
 332
 333         char                            uuid[16];
 334
 335         /* If the array is being reshaped, we need to record the
 336          * new shape and an indication of where we are up to.
 337          * This is written to the superblock.
 338          * If reshape_position is MaxSector, then no reshape is happening (yet).
 339          */
 340         sector_t                        reshape_position;
 341         int                             delta_disks, new_level, new_layout;
 342         int                             new_chunk_sectors;
 343         int                             reshape_backwards;
 344
 345         struct md_thread                *thread;        /* management thread */
 346         struct md_thread                *sync_thread;   /* doing resync or reconstruct */
 347
 348         /* 'last_sync_action' is initialized to "none".  It is set when a
 349          * sync operation (i.e "data-check", "requested-resync", "resync",
 350          * "recovery", or "reshape") is started.  It holds this value even
 351          * when the sync thread is "frozen" (interrupted) or "idle" (stopped
 352          * or finished).  It is overwritten when a new sync operation is begun.
 353          */
 354         char                            *last_sync_action;
 355         sector_t                        curr_resync;    /* last block scheduled */
 356         /* As resync requests can complete out of order, we cannot easily track
 357          * how much resync has been completed.  So we occasionally pause until
 358          * everything completes, then set curr_resync_completed to curr_resync.
 359          * As such it may be well behind the real resync mark, but it is a value
 360          * we are certain of.
 361          */
 362         sector_t                        curr_resync_completed;
 363         unsigned long                   resync_mark;    /* a recent timestamp */
 364         sector_t                        resync_mark_cnt;/* blocks written at resync_mark */
 365         sector_t                        curr_mark_cnt; /* blocks scheduled now */
 366
 367         sector_t                        resync_max_sectors; /* may be set by personality */
 368
 369         atomic64_t                      resync_mismatches; /* count of sectors where
 370                                                             * parity/replica mismatch found
 371                                                             */
 372
 373         /* allow user-space to request suspension of IO to regions of the array */
 374         sector_t                        suspend_lo;
 375         sector_t                        suspend_hi;
 376         /* if zero, use the system-wide default */
 377         int                             sync_speed_min;
 378         int                             sync_speed_max;
 379
 380         /* resync even though the same disks are shared among md-devices */
 381         int                             parallel_resync;
 382
 383         int                             ok_start_degraded;
 384
 385         unsigned long                   recovery;
 386         /* If a RAID personality determines that recovery (of a particular
 387          * device) will fail due to a read error on the source device, it
 388          * takes a copy of this number and does not attempt recovery again
 389          * until this number changes.
 390          */
 391         int                             recovery_disabled;
 392
 393         int                             in_sync;        /* know to not need resync */
 394         /* 'open_mutex' avoids races between 'md_open' and 'do_md_stop', so
 395          * that we are never stopping an array while it is open.
 396          * 'reconfig_mutex' protects all other reconfiguration.
 397          * These locks are separate due to conflicting interactions
 398          * with bdev->bd_mutex.
 399          * Lock ordering is:
 400          *  reconfig_mutex -> bd_mutex
 401          *  bd_mutex -> open_mutex:  e.g. __blkdev_get -> md_open
 402          */
 403         struct mutex                    open_mutex;
 404         struct mutex                    reconfig_mutex;
 405         atomic_t                        active;         /* general refcount */
 406         atomic_t                        openers;        /* number of active opens */
 407
 408         int                             changed;        /* True if we might need to
 409                                                          * reread partition info */
 410         int                             degraded;       /* whether md should consider
 411                                                          * adding a spare
 412                                                          */
 413
 414         atomic_t                        recovery_active; /* blocks scheduled, but not written */
 415         wait_queue_head_t               recovery_wait;
 416         sector_t                        recovery_cp;
 417         sector_t                        resync_min;     /* user requested sync
 418                                                          * starts here */
 419         sector_t                        resync_max;     /* resync should pause
 420                                                          * when it gets here */
 421
 422         struct kernfs_node              *sysfs_state;   /* handle for 'array_state'
 423                                                          * file in sysfs.
 424                                                          */
 425         struct kernfs_node              *sysfs_action;  /* handle for 'sync_action' */
 426         struct kernfs_node              *sysfs_completed;       /*handle for 'sync_completed' */
 427         struct kernfs_node              *sysfs_degraded;        /*handle for 'degraded' */
 428         struct kernfs_node              *sysfs_level;           /*handle for 'level' */
 429
 430         struct work_struct del_work;    /* used for delayed sysfs removal */
 431
 432         /* "lock" protects:
 433          *   flush_bio transition from NULL to !NULL
 434          *   rdev superblocks, events
 435          *   clearing MD_CHANGE_*
 436          *   in_sync - and related safemode and MD_CHANGE changes
 437          *   pers (also protected by reconfig_mutex and pending IO).
 438          *   clearing ->bitmap
 439          *   clearing ->bitmap_info.file
 440          *   changing ->resync_{min,max}
 441          *   setting MD_RECOVERY_RUNNING (which interacts with resync_{min,max})
 442          */
 443         spinlock_t                      lock;
 444         wait_queue_head_t               sb_wait;        /* for waiting on superblock updates */
 445         atomic_t                        pending_writes; /* number of active superblock writes */
 446
 447         unsigned int                    safemode;       /* if set, update "clean" superblock
 448                                                          * when no writes pending.
 449                                                          */
 450         unsigned int                    safemode_delay;
 451         struct timer_list               safemode_timer;
 452         struct percpu_ref               writes_pending;
 453         int                             sync_checkers;  /* # of threads checking writes_pending */
 454         struct request_queue            *queue; /* for plugging ... */
 455
 456         struct bitmap                   *bitmap; /* the bitmap for the device */
 457         struct {
 458                 struct file             *file; /* the bitmap file */
 459                 loff_t                  offset; /* offset from superblock of
 460                                                  * start of bitmap. May be
 461                                                  * negative, but not '0'
 462                                                  * For external metadata, offset
 463                                                  * from start of device.
 464                                                  */
 465                 unsigned long           space; /* space available at this offset */
 466                 loff_t                  default_offset; /* this is the offset to use when
 467                                                          * hot-adding a bitmap.  It should
 468                                                          * eventually be settable by sysfs.
 469                                                          */
 470                 unsigned long           default_space; /* space available at
 471                                                         * default offset */
 472                 struct mutex            mutex;
 473                 unsigned long           chunksize;
 474                 unsigned long           daemon_sleep; /* how many jiffies between updates? */
 475                 unsigned long           max_write_behind; /* write-behind mode */
 476                 int                     external;
 477                 int                     nodes; /* Maximum number of nodes in the cluster */
 478                 char                    cluster_name[64]; /* Name of the cluster */
 479         } bitmap_info;
 480
 481         atomic_t                        max_corr_read_errors; /* max read retries */
 482         struct list_head                all_mddevs;
 483
 484         struct attribute_group          *to_remove;
 485
 486         struct bio_set                  bio_set;
 487         struct bio_set                  sync_set; /* for sync operations like
 488                                                    * metadata and bitmap writes
 489                                                    */
 490         mempool_t                       md_io_pool;
 491
 492         /* Generic flush handling.
 493          * The last to finish preflush schedules a worker to submit
 494          * the rest of the request (without the REQ_PREFLUSH flag).
 495          */
 496         struct bio *flush_bio;
 497         atomic_t flush_pending;
 498         ktime_t start_flush, prev_flush_start; /* prev_flush_start is when the previous completed
 499                                                 * flush was started.
 500                                                 */
 501         struct work_struct flush_work;
 502         struct work_struct event_work;  /* used by dm to report failure event */
 503         mempool_t *serial_info_pool;
 504         void (*sync_super)(struct mddev *mddev, struct md_rdev *rdev);
 505         struct md_cluster_info          *cluster_info;
 506         unsigned int                    good_device_nr; /* good device num within cluster raid */
 507         unsigned int                    noio_flag; /* for memalloc scope API */
 508
 509         bool    has_superblocks:1;
 510         bool    fail_last_dev:1;
 511         bool    serialize_policy:1;
 512 };
 513
 514 enum recovery_flags {
 515         /*
 516          * If neither SYNC or RESHAPE are set, then it is a recovery.
 517          */
 518         MD_RECOVERY_RUNNING,    /* a thread is running, or about to be started */
 519         MD_RECOVERY_SYNC,       /* actually doing a resync, not a recovery */
 520         MD_RECOVERY_RECOVER,    /* doing recovery, or need to try it. */
 521         MD_RECOVERY_INTR,       /* resync needs to be aborted for some reason */
 522         MD_RECOVERY_DONE,       /* thread is done and is waiting to be reaped */
 523         MD_RECOVERY_NEEDED,     /* we might need to start a resync/recover */
 524         MD_RECOVERY_REQUESTED,  /* user-space has requested a sync (used with SYNC) */
 525         MD_RECOVERY_CHECK,      /* user-space request for check-only, no repair */
 526         MD_RECOVERY_RESHAPE,    /* A reshape is happening */
 527         MD_RECOVERY_FROZEN,     /* User request to abort, and not restart, any action */
 528         MD_RECOVERY_ERROR,      /* sync-action interrupted because io-error */
 529         MD_RECOVERY_WAIT,       /* waiting for pers->start() to finish */
 530         MD_RESYNCING_REMOTE,    /* remote node is running resync thread */
 531 };
 532
 533 static inline int __must_check mddev_lock(struct mddev *mddev)
 534 {
 535         return mutex_lock_interruptible(&mddev->reconfig_mutex);
 536 }
 537
 538 /* Sometimes we need to take the lock in a situation where
 539  * failure due to interrupts is not acceptable.
 540  */
 541 static inline void mddev_lock_nointr(struct mddev *mddev)
 542 {
 543         mutex_lock(&mddev->reconfig_mutex);
 544 }
 545
 546 static inline int mddev_trylock(struct mddev *mddev)
 547 {
 548         return mutex_trylock(&mddev->reconfig_mutex);
 549 }
 550 extern void mddev_unlock(struct mddev *mddev);
 551
 552 static inline void md_sync_acct(struct block_device *bdev, unsigned long nr_sectors)
 553 {
 554         atomic_add(nr_sectors, &bdev->bd_disk->sync_io);
 555 }
 556
 557 static inline void md_sync_acct_bio(struct bio *bio, unsigned long nr_sectors)
 558 {
 559         atomic_add(nr_sectors, &bio->bi_disk->sync_io);
 560 }
 561
 562 struct md_personality
 563 {
 564         char *name;
 565         int level;
 566         struct list_head list;
 567         struct module *owner;
 568         bool __must_check (*make_request)(struct mddev *mddev, struct bio *bio);
 569         /*
 570          * start up works that do NOT require md_thread. tasks that
 571          * requires md_thread should go into start()
 572          */
 573         int (*run)(struct mddev *mddev);
 574         /* start up works that require md threads */
 575         int (*start)(struct mddev *mddev);
 576         void (*free)(struct mddev *mddev, void *priv);
 577         void (*status)(struct seq_file *seq, struct mddev *mddev);
 578         /* error_handler must set ->faulty and clear ->in_sync
 579          * if appropriate, and should abort recovery if needed
 580          */
 581         void (*error_handler)(struct mddev *mddev, struct md_rdev *rdev);
 582         int (*hot_add_disk) (struct mddev *mddev, struct md_rdev *rdev);
 583         int (*hot_remove_disk) (struct mddev *mddev, struct md_rdev *rdev);
 584         int (*spare_active) (struct mddev *mddev);
 585         sector_t (*sync_request)(struct mddev *mddev, sector_t sector_nr, int *skipped);
 586         int (*resize) (struct mddev *mddev, sector_t sectors);
 587         sector_t (*size) (struct mddev *mddev, sector_t sectors, int raid_disks);
 588         int (*check_reshape) (struct mddev *mddev);
 589         int (*start_reshape) (struct mddev *mddev);
 590         void (*finish_reshape) (struct mddev *mddev);
 591         void (*update_reshape_pos) (struct mddev *mddev);
 592         /* quiesce suspends or resumes internal processing.
 593          * 1 - stop new actions and wait for action io to complete
 594          * 0 - return to normal behaviour
 595          */
 596         void (*quiesce) (struct mddev *mddev, int quiesce);
 597         /* takeover is used to transition an array from one
 598          * personality to another.  The new personality must be able
 599          * to handle the data in the current layout.
 600          * e.g. 2drive raid1 -> 2drive raid5
 601          *      ndrive raid5 -> degraded n+1drive raid6 with special layout
 602          * If the takeover succeeds, a new 'private' structure is returned.
 603          * This needs to be installed and then ->run used to activate the
 604          * array.
 605          */
 606         void *(*takeover) (struct mddev *mddev);
 607         /* Changes the consistency policy of an active array. */
 608         int (*change_consistency_policy)(struct mddev *mddev, const char *buf);
 609 };
 610
 611 struct md_sysfs_entry {
 612         struct attribute attr;
 613         ssize_t (*show)(struct mddev *, char *);
 614         ssize_t (*store)(struct mddev *, const char *, size_t);
 615 };
 616 extern struct attribute_group md_bitmap_group;
 617
 618 static inline struct kernfs_node *sysfs_get_dirent_safe(struct kernfs_node *sd, char *name)
 619 {
 620         if (sd)
 621                 return sysfs_get_dirent(sd, name);
 622         return sd;
 623 }
 624 static inline void sysfs_notify_dirent_safe(struct kernfs_node *sd)
 625 {
 626         if (sd)
 627                 sysfs_notify_dirent(sd);
 628 }
 629
 630 static inline char * mdname (struct mddev * mddev)
 631 {
 632         return mddev->gendisk ? mddev->gendisk->disk_name : "mdX";
 633 }
 634
 635 static inline int sysfs_link_rdev(struct mddev *mddev, struct md_rdev *rdev)
 636 {
 637         char nm[20];
 638         if (!test_bit(Replacement, &rdev->flags) &&
 639             !test_bit(Journal, &rdev->flags) &&
 640             mddev->kobj.sd) {
 641                 sprintf(nm, "rd%d", rdev->raid_disk);
 642                 return sysfs_create_link(&mddev->kobj, &rdev->kobj, nm);
 643         } else
 644                 return 0;
 645 }
 646
 647 static inline void sysfs_unlink_rdev(struct mddev *mddev, struct md_rdev *rdev)
 648 {
 649         char nm[20];
 650         if (!test_bit(Replacement, &rdev->flags) &&
 651             !test_bit(Journal, &rdev->flags) &&
 652             mddev->kobj.sd) {
 653                 sprintf(nm, "rd%d", rdev->raid_disk);
 654                 sysfs_remove_link(&mddev->kobj, nm);
 655         }
 656 }
 657
 658 /*
 659  * iterates through some rdev ringlist. It's safe to remove the
 660  * current 'rdev'. Dont touch 'tmp' though.
 661  */
 662 #define rdev_for_each_list(rdev, tmp, head)                             \
 663         list_for_each_entry_safe(rdev, tmp, head, same_set)
 664
 665 /*
 666  * iterates through the 'same array disks' ringlist
 667  */
 668 #define rdev_for_each(rdev, mddev)                              \
 669         list_for_each_entry(rdev, &((mddev)->disks), same_set)
 670
 671 #define rdev_for_each_safe(rdev, tmp, mddev)                            \
 672         list_for_each_entry_safe(rdev, tmp, &((mddev)->disks), same_set)
 673
 674 #define rdev_for_each_rcu(rdev, mddev)                          \
 675         list_for_each_entry_rcu(rdev, &((mddev)->disks), same_set)
 676
 677 struct md_thread {
 678         void                    (*run) (struct md_thread *thread);
 679         struct mddev            *mddev;
 680         wait_queue_head_t       wqueue;
 681         unsigned long           flags;
 682         struct task_struct      *tsk;
 683         unsigned long           timeout;
 684         void                    *private;
 685 };
 686
 687 #define THREAD_WAKEUP  0
 688
 689 static inline void safe_put_page(struct page *p)
 690 {
 691         if (p) put_page(p);
 692 }
 693
 694 extern int register_md_personality(struct md_personality *p);
 695 extern int unregister_md_personality(struct md_personality *p);
 696 extern int register_md_cluster_operations(struct md_cluster_operations *ops,
 697                 struct module *module);
 698 extern int unregister_md_cluster_operations(void);
 699 extern int md_setup_cluster(struct mddev *mddev, int nodes);
 700 extern void md_cluster_stop(struct mddev *mddev);
 701 extern struct md_thread *md_register_thread(
 702         void (*run)(struct md_thread *thread),
 703         struct mddev *mddev,
 704         const char *name);
 705 extern void md_unregister_thread(struct md_thread **threadp);
 706 extern void md_wakeup_thread(struct md_thread *thread);
 707 extern void md_check_recovery(struct mddev *mddev);
 708 extern void md_reap_sync_thread(struct mddev *mddev);
 709 extern int mddev_init_writes_pending(struct mddev *mddev);
 710 extern bool md_write_start(struct mddev *mddev, struct bio *bi);
 711 extern void md_write_inc(struct mddev *mddev, struct bio *bi);
 712 extern void md_write_end(struct mddev *mddev);
 713 extern void md_done_sync(struct mddev *mddev, int blocks, int ok);
 714 extern void md_error(struct mddev *mddev, struct md_rdev *rdev);
 715 extern void md_finish_reshape(struct mddev *mddev);
 716 void md_submit_discard_bio(struct mddev *mddev, struct md_rdev *rdev,
 717                         struct bio *bio, sector_t start, sector_t size);
 718
 719 extern bool __must_check md_flush_request(struct mddev *mddev, struct bio *bio);
 720 extern void md_super_write(struct mddev *mddev, struct md_rdev *rdev,
 721                            sector_t sector, int size, struct page *page);
 722 extern int md_super_wait(struct mddev *mddev);
 723 extern int sync_page_io(struct md_rdev *rdev, sector_t sector, int size,
 724                         struct page *page, int op, int op_flags,
 725                         bool metadata_op);
 726 extern void md_do_sync(struct md_thread *thread);
 727 extern void md_new_event(struct mddev *mddev);
 728 extern void md_allow_write(struct mddev *mddev);
 729 extern void md_wait_for_blocked_rdev(struct md_rdev *rdev, struct mddev *mddev);
 730 extern void md_set_array_sectors(struct mddev *mddev, sector_t array_sectors);
 731 extern int md_check_no_bitmap(struct mddev *mddev);
 732 extern int md_integrity_register(struct mddev *mddev);
 733 extern int md_integrity_add_rdev(struct md_rdev *rdev, struct mddev *mddev);
 734 extern int strict_strtoul_scaled(const char *cp, unsigned long *res, int scale);
 735
 736 extern void mddev_init(struct mddev *mddev);
 737 extern int md_run(struct mddev *mddev);
 738 extern int md_start(struct mddev *mddev);
 739 extern void md_stop(struct mddev *mddev);
 740 extern void md_stop_writes(struct mddev *mddev);
 741 extern int md_rdev_init(struct md_rdev *rdev);
 742 extern void md_rdev_clear(struct md_rdev *rdev);
 743
 744 extern void md_handle_request(struct mddev *mddev, struct bio *bio);
 745 extern void mddev_suspend(struct mddev *mddev);
 746 extern void mddev_resume(struct mddev *mddev);
 747 extern struct bio *bio_alloc_mddev(gfp_t gfp_mask, int nr_iovecs,
 748                                    struct mddev *mddev);
 749
 750 extern void md_reload_sb(struct mddev *mddev, int raid_disk);
 751 extern void md_update_sb(struct mddev *mddev, int force);
 752 extern void md_kick_rdev_from_array(struct md_rdev * rdev);
 753 extern void mddev_create_serial_pool(struct mddev *mddev, struct md_rdev *rdev,
 754                                      bool is_suspend);
 755 extern void mddev_destroy_serial_pool(struct mddev *mddev, struct md_rdev *rdev,
 756                                       bool is_suspend);
 757 struct md_rdev *md_find_rdev_nr_rcu(struct mddev *mddev, int nr);
 758 struct md_rdev *md_find_rdev_rcu(struct mddev *mddev, dev_t dev);
 759
 760 static inline bool is_mddev_broken(struct md_rdev *rdev, const char *md_type)
 761 {
 762         int flags = rdev->bdev->bd_disk->flags;
 763
 764         if (!(flags & GENHD_FL_UP)) {
 765                 if (!test_and_set_bit(MD_BROKEN, &rdev->mddev->flags))
 766                         pr_warn("md: %s: %s array has a missing/failed member\n",
 767                                 mdname(rdev->mddev), md_type);
 768                 return true;
 769         }
 770         return false;
 771 }
 772
 773 static inline void rdev_dec_pending(struct md_rdev *rdev, struct mddev *mddev)
 774 {
 775         int faulty = test_bit(Faulty, &rdev->flags);
 776         if (atomic_dec_and_test(&rdev->nr_pending) && faulty) {
 777                 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
 778                 md_wakeup_thread(mddev->thread);
 779         }
 780 }
 781
 782 extern struct md_cluster_operations *md_cluster_ops;
 783 static inline int mddev_is_clustered(struct mddev *mddev)
 784 {
 785         return mddev->cluster_info && mddev->bitmap_info.nodes > 1;
 786 }
 787
 788 /* clear unsupported mddev_flags */
 789 static inline void mddev_clear_unsupported_flags(struct mddev *mddev,
 790         unsigned long unsupported_flags)
 791 {
 792         mddev->flags &= ~unsupported_flags;
 793 }
 794
 795 static inline void mddev_check_writesame(struct mddev *mddev, struct bio *bio)
 796 {
 797         if (bio_op(bio) == REQ_OP_WRITE_SAME &&
 798             !bio->bi_disk->queue->limits.max_write_same_sectors)
 799                 mddev->queue->limits.max_write_same_sectors = 0;
 800 }
 801
 802 static inline void mddev_check_write_zeroes(struct mddev *mddev, struct bio *bio)
 803 {
 804         if (bio_op(bio) == REQ_OP_WRITE_ZEROES &&
 805             !bio->bi_disk->queue->limits.max_write_zeroes_sectors)
 806                 mddev->queue->limits.max_write_zeroes_sectors = 0;
 807 }
 808
 809 struct mdu_array_info_s;
 810 struct mdu_disk_info_s;
 811
 812 extern int mdp_major;
 813 void md_autostart_arrays(int part);
 814 int md_set_array_info(struct mddev *mddev, struct mdu_array_info_s *info);
 815 int md_add_new_disk(struct mddev *mddev, struct mdu_disk_info_s *info);
 816 int do_md_run(struct mddev *mddev);
 817
 818 extern const struct block_device_operations md_fops;
 819
 820 #endif /* _MD_MD_H */