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