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