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 struct mddev {
 256         void                            *private;
 257         struct md_personality           *pers;
 258         dev_t                           unit;
 259         int                             md_minor;
 260         struct list_head                disks;
 261         unsigned long                   flags;
 262         unsigned long                   sb_flags;
 263
 264         int                             suspended;
 265         atomic_t                        active_io;
 266         int                             ro;
 267         int                             sysfs_active; /* set when sysfs deletes
 268                                                        * are happening, so run/
 269                                                        * takeover/stop are not safe
 270                                                        */
 271         struct gendisk                  *gendisk;
 272
 273         struct kobject                  kobj;
 274         int                             hold_active;
 275 #define UNTIL_IOCTL     1
 276 #define UNTIL_STOP      2
 277
 278         /* Superblock information */
 279         int                             major_version,
 280                                         minor_version,
 281                                         patch_version;
 282         int                             persistent;
 283         int                             external;       /* metadata is
 284                                                          * managed externally */
 285         char                            metadata_type[17]; /* externally set*/
 286         int                             chunk_sectors;
 287         time64_t                        ctime, utime;
 288         int                             level, layout;
 289         char                            clevel[16];
 290         int                             raid_disks;
 291         int                             max_disks;
 292         sector_t                        dev_sectors;    /* used size of
 293                                                          * component devices */
 294         sector_t                        array_sectors; /* exported array size */
 295         int                             external_size; /* size managed
 296                                                         * externally */
 297         __u64                           events;
 298         /* If the last 'event' was simply a clean->dirty transition, and
 299          * we didn't write it to the spares, then it is safe and simple
 300          * to just decrement the event count on a dirty->clean transition.
 301          * So we record that possibility here.
 302          */
 303         int                             can_decrease_events;
 304
 305         char                            uuid[16];
 306
 307         /* If the array is being reshaped, we need to record the
 308          * new shape and an indication of where we are up to.
 309          * This is written to the superblock.
 310          * If reshape_position is MaxSector, then no reshape is happening (yet).
 311          */
 312         sector_t                        reshape_position;
 313         int                             delta_disks, new_level, new_layout;
 314         int                             new_chunk_sectors;
 315         int                             reshape_backwards;
 316
 317         struct md_thread                *thread;        /* management thread */
 318         struct md_thread                *sync_thread;   /* doing resync or reconstruct */
 319
 320         /* 'last_sync_action' is initialized to "none".  It is set when a
 321          * sync operation (i.e "data-check", "requested-resync", "resync",
 322          * "recovery", or "reshape") is started.  It holds this value even
 323          * when the sync thread is "frozen" (interrupted) or "idle" (stopped
 324          * or finished).  It is overwritten when a new sync operation is begun.
 325          */
 326         char                            *last_sync_action;
 327         sector_t                        curr_resync;    /* last block scheduled */
 328         /* As resync requests can complete out of order, we cannot easily track
 329          * how much resync has been completed.  So we occasionally pause until
 330          * everything completes, then set curr_resync_completed to curr_resync.
 331          * As such it may be well behind the real resync mark, but it is a value
 332          * we are certain of.
 333          */
 334         sector_t                        curr_resync_completed;
 335         unsigned long                   resync_mark;    /* a recent timestamp */
 336         sector_t                        resync_mark_cnt;/* blocks written at resync_mark */
 337         sector_t                        curr_mark_cnt; /* blocks scheduled now */
 338
 339         sector_t                        resync_max_sectors; /* may be set by personality */
 340
 341         atomic64_t                      resync_mismatches; /* count of sectors where
 342                                                             * parity/replica mismatch found
 343                                                             */
 344
 345         /* allow user-space to request suspension of IO to regions of the array */
 346         sector_t                        suspend_lo;
 347         sector_t                        suspend_hi;
 348         /* if zero, use the system-wide default */
 349         int                             sync_speed_min;
 350         int                             sync_speed_max;
 351
 352         /* resync even though the same disks are shared among md-devices */
 353         int                             parallel_resync;
 354
 355         int                             ok_start_degraded;
 356
 357         unsigned long                   recovery;
 358         /* If a RAID personality determines that recovery (of a particular
 359          * device) will fail due to a read error on the source device, it
 360          * takes a copy of this number and does not attempt recovery again
 361          * until this number changes.
 362          */
 363         int                             recovery_disabled;
 364
 365         int                             in_sync;        /* know to not need resync */
 366         /* 'open_mutex' avoids races between 'md_open' and 'do_md_stop', so
 367          * that we are never stopping an array while it is open.
 368          * 'reconfig_mutex' protects all other reconfiguration.
 369          * These locks are separate due to conflicting interactions
 370          * with bdev->bd_mutex.
 371          * Lock ordering is:
 372          *  reconfig_mutex -> bd_mutex : e.g. do_md_run -> revalidate_disk
 373          *  bd_mutex -> open_mutex:  e.g. __blkdev_get -> md_open
 374          */
 375         struct mutex                    open_mutex;
 376         struct mutex                    reconfig_mutex;
 377         atomic_t                        active;         /* general refcount */
 378         atomic_t                        openers;        /* number of active opens */
 379
 380         int                             changed;        /* True if we might need to
 381                                                          * reread partition info */
 382         int                             degraded;       /* whether md should consider
 383                                                          * adding a spare
 384                                                          */
 385
 386         atomic_t                        recovery_active; /* blocks scheduled, but not written */
 387         wait_queue_head_t               recovery_wait;
 388         sector_t                        recovery_cp;
 389         sector_t                        resync_min;     /* user requested sync
 390                                                          * starts here */
 391         sector_t                        resync_max;     /* resync should pause
 392                                                          * when it gets here */
 393
 394         struct kernfs_node              *sysfs_state;   /* handle for 'array_state'
 395                                                          * file in sysfs.
 396                                                          */
 397         struct kernfs_node              *sysfs_action;  /* handle for 'sync_action' */
 398
 399         struct work_struct del_work;    /* used for delayed sysfs removal */
 400
 401         /* "lock" protects:
 402          *   flush_bio transition from NULL to !NULL
 403          *   rdev superblocks, events
 404          *   clearing MD_CHANGE_*
 405          *   in_sync - and related safemode and MD_CHANGE changes
 406          *   pers (also protected by reconfig_mutex and pending IO).
 407          *   clearing ->bitmap
 408          *   clearing ->bitmap_info.file
 409          *   changing ->resync_{min,max}
 410          *   setting MD_RECOVERY_RUNNING (which interacts with resync_{min,max})
 411          */
 412         spinlock_t                      lock;
 413         wait_queue_head_t               sb_wait;        /* for waiting on superblock updates */
 414         atomic_t                        pending_writes; /* number of active superblock writes */
 415
 416         unsigned int                    safemode;       /* if set, update "clean" superblock
 417                                                          * when no writes pending.
 418                                                          */
 419         unsigned int                    safemode_delay;
 420         struct timer_list               safemode_timer;
 421         struct percpu_ref               writes_pending;
 422         int                             sync_checkers;  /* # of threads checking writes_pending */
 423         struct request_queue            *queue; /* for plugging ... */
 424
 425         struct bitmap                   *bitmap; /* the bitmap for the device */
 426         struct {
 427                 struct file             *file; /* the bitmap file */
 428                 loff_t                  offset; /* offset from superblock of
 429                                                  * start of bitmap. May be
 430                                                  * negative, but not '0'
 431                                                  * For external metadata, offset
 432                                                  * from start of device.
 433                                                  */
 434                 unsigned long           space; /* space available at this offset */
 435                 loff_t                  default_offset; /* this is the offset to use when
 436                                                          * hot-adding a bitmap.  It should
 437                                                          * eventually be settable by sysfs.
 438                                                          */
 439                 unsigned long           default_space; /* space available at
 440                                                         * default offset */
 441                 struct mutex            mutex;
 442                 unsigned long           chunksize;
 443                 unsigned long           daemon_sleep; /* how many jiffies between updates? */
 444                 unsigned long           max_write_behind; /* write-behind mode */
 445                 int                     external;
 446                 int                     nodes; /* Maximum number of nodes in the cluster */
 447                 char                    cluster_name[64]; /* Name of the cluster */
 448         } bitmap_info;
 449
 450         atomic_t                        max_corr_read_errors; /* max read retries */
 451         struct list_head                all_mddevs;
 452
 453         struct attribute_group          *to_remove;
 454
 455         struct bio_set                  *bio_set;
 456         struct bio_set                  *sync_set; /* for sync operations like
 457                                                    * metadata and bitmap writes
 458                                                    */
 459
 460         /* Generic flush handling.
 461          * The last to finish preflush schedules a worker to submit
 462          * the rest of the request (without the REQ_PREFLUSH flag).
 463          */
 464         struct bio *flush_bio;
 465         atomic_t flush_pending;
 466         struct work_struct flush_work;
 467         struct work_struct event_work;  /* used by dm to report failure event */
 468         void (*sync_super)(struct mddev *mddev, struct md_rdev *rdev);
 469         struct md_cluster_info          *cluster_info;
 470         unsigned int                    good_device_nr; /* good device num within cluster raid */
 471
 472         bool    has_superblocks:1;
 473 };
 474
 475 enum recovery_flags {
 476         /*
 477          * If neither SYNC or RESHAPE are set, then it is a recovery.
 478          */
 479         MD_RECOVERY_RUNNING,    /* a thread is running, or about to be started */
 480         MD_RECOVERY_SYNC,       /* actually doing a resync, not a recovery */
 481         MD_RECOVERY_RECOVER,    /* doing recovery, or need to try it. */
 482         MD_RECOVERY_INTR,       /* resync needs to be aborted for some reason */
 483         MD_RECOVERY_DONE,       /* thread is done and is waiting to be reaped */
 484         MD_RECOVERY_NEEDED,     /* we might need to start a resync/recover */
 485         MD_RECOVERY_REQUESTED,  /* user-space has requested a sync (used with SYNC) */
 486         MD_RECOVERY_CHECK,      /* user-space request for check-only, no repair */
 487         MD_RECOVERY_RESHAPE,    /* A reshape is happening */
 488         MD_RECOVERY_FROZEN,     /* User request to abort, and not restart, any action */
 489         MD_RECOVERY_ERROR,      /* sync-action interrupted because io-error */
 490         MD_RECOVERY_WAIT,       /* waiting for pers->start() to finish */
 491 };
 492
 493 static inline int __must_check mddev_lock(struct mddev *mddev)
 494 {
 495         return mutex_lock_interruptible(&mddev->reconfig_mutex);
 496 }
 497
 498 /* Sometimes we need to take the lock in a situation where
 499  * failure due to interrupts is not acceptable.
 500  */
 501 static inline void mddev_lock_nointr(struct mddev *mddev)
 502 {
 503         mutex_lock(&mddev->reconfig_mutex);
 504 }
 505
 506 static inline int mddev_trylock(struct mddev *mddev)
 507 {
 508         return mutex_trylock(&mddev->reconfig_mutex);
 509 }
 510 extern void mddev_unlock(struct mddev *mddev);
 511
 512 static inline void md_sync_acct(struct block_device *bdev, unsigned long nr_sectors)
 513 {
 514         atomic_add(nr_sectors, &bdev->bd_contains->bd_disk->sync_io);
 515 }
 516
 517 static inline void md_sync_acct_bio(struct bio *bio, unsigned long nr_sectors)
 518 {
 519         atomic_add(nr_sectors, &bio->bi_disk->sync_io);
 520 }
 521
 522 struct md_personality
 523 {
 524         char *name;
 525         int level;
 526         struct list_head list;
 527         struct module *owner;
 528         bool (*make_request)(struct mddev *mddev, struct bio *bio);
 529         /*
 530          * start up works that do NOT require md_thread. tasks that
 531          * requires md_thread should go into start()
 532          */
 533         int (*run)(struct mddev *mddev);
 534         /* start up works that require md threads */
 535         int (*start)(struct mddev *mddev);
 536         void (*free)(struct mddev *mddev, void *priv);
 537         void (*status)(struct seq_file *seq, struct mddev *mddev);
 538         /* error_handler must set ->faulty and clear ->in_sync
 539          * if appropriate, and should abort recovery if needed
 540          */
 541         void (*error_handler)(struct mddev *mddev, struct md_rdev *rdev);
 542         int (*hot_add_disk) (struct mddev *mddev, struct md_rdev *rdev);
 543         int (*hot_remove_disk) (struct mddev *mddev, struct md_rdev *rdev);
 544         int (*spare_active) (struct mddev *mddev);
 545         sector_t (*sync_request)(struct mddev *mddev, sector_t sector_nr, int *skipped);
 546         int (*resize) (struct mddev *mddev, sector_t sectors);
 547         sector_t (*size) (struct mddev *mddev, sector_t sectors, int raid_disks);
 548         int (*check_reshape) (struct mddev *mddev);
 549         int (*start_reshape) (struct mddev *mddev);
 550         void (*finish_reshape) (struct mddev *mddev);
 551         /* quiesce suspends or resumes internal processing.
 552          * 1 - stop new actions and wait for action io to complete
 553          * 0 - return to normal behaviour
 554          */
 555         void (*quiesce) (struct mddev *mddev, int quiesce);
 556         /* takeover is used to transition an array from one
 557          * personality to another.  The new personality must be able
 558          * to handle the data in the current layout.
 559          * e.g. 2drive raid1 -> 2drive raid5
 560          *      ndrive raid5 -> degraded n+1drive raid6 with special layout
 561          * If the takeover succeeds, a new 'private' structure is returned.
 562          * This needs to be installed and then ->run used to activate the
 563          * array.
 564          */
 565         void *(*takeover) (struct mddev *mddev);
 566         /* congested implements bdi.congested_fn().
 567          * Will not be called while array is 'suspended' */
 568         int (*congested)(struct mddev *mddev, int bits);
 569         /* Changes the consistency policy of an active array. */
 570         int (*change_consistency_policy)(struct mddev *mddev, const char *buf);
 571 };
 572
 573 struct md_sysfs_entry {
 574         struct attribute attr;
 575         ssize_t (*show)(struct mddev *, char *);
 576         ssize_t (*store)(struct mddev *, const char *, size_t);
 577 };
 578 extern struct attribute_group md_bitmap_group;
 579
 580 static inline struct kernfs_node *sysfs_get_dirent_safe(struct kernfs_node *sd, char *name)
 581 {
 582         if (sd)
 583                 return sysfs_get_dirent(sd, name);
 584         return sd;
 585 }
 586 static inline void sysfs_notify_dirent_safe(struct kernfs_node *sd)
 587 {
 588         if (sd)
 589                 sysfs_notify_dirent(sd);
 590 }
 591
 592 static inline char * mdname (struct mddev * mddev)
 593 {
 594         return mddev->gendisk ? mddev->gendisk->disk_name : "mdX";
 595 }
 596
 597 static inline int sysfs_link_rdev(struct mddev *mddev, struct md_rdev *rdev)
 598 {
 599         char nm[20];
 600         if (!test_bit(Replacement, &rdev->flags) &&
 601             !test_bit(Journal, &rdev->flags) &&
 602             mddev->kobj.sd) {
 603                 sprintf(nm, "rd%d", rdev->raid_disk);
 604                 return sysfs_create_link(&mddev->kobj, &rdev->kobj, nm);
 605         } else
 606                 return 0;
 607 }
 608
 609 static inline void sysfs_unlink_rdev(struct mddev *mddev, struct md_rdev *rdev)
 610 {
 611         char nm[20];
 612         if (!test_bit(Replacement, &rdev->flags) &&
 613             !test_bit(Journal, &rdev->flags) &&
 614             mddev->kobj.sd) {
 615                 sprintf(nm, "rd%d", rdev->raid_disk);
 616                 sysfs_remove_link(&mddev->kobj, nm);
 617         }
 618 }
 619
 620 /*
 621  * iterates through some rdev ringlist. It's safe to remove the
 622  * current 'rdev'. Dont touch 'tmp' though.
 623  */
 624 #define rdev_for_each_list(rdev, tmp, head)                             \
 625         list_for_each_entry_safe(rdev, tmp, head, same_set)
 626
 627 /*
 628  * iterates through the 'same array disks' ringlist
 629  */
 630 #define rdev_for_each(rdev, mddev)                              \
 631         list_for_each_entry(rdev, &((mddev)->disks), same_set)
 632
 633 #define rdev_for_each_safe(rdev, tmp, mddev)                            \
 634         list_for_each_entry_safe(rdev, tmp, &((mddev)->disks), same_set)
 635
 636 #define rdev_for_each_rcu(rdev, mddev)                          \
 637         list_for_each_entry_rcu(rdev, &((mddev)->disks), same_set)
 638
 639 struct md_thread {
 640         void                    (*run) (struct md_thread *thread);
 641         struct mddev            *mddev;
 642         wait_queue_head_t       wqueue;
 643         unsigned long           flags;
 644         struct task_struct      *tsk;
 645         unsigned long           timeout;
 646         void                    *private;
 647 };
 648
 649 #define THREAD_WAKEUP  0
 650
 651 static inline void safe_put_page(struct page *p)
 652 {
 653         if (p) put_page(p);
 654 }
 655
 656 extern int register_md_personality(struct md_personality *p);
 657 extern int unregister_md_personality(struct md_personality *p);
 658 extern int register_md_cluster_operations(struct md_cluster_operations *ops,
 659                 struct module *module);
 660 extern int unregister_md_cluster_operations(void);
 661 extern int md_setup_cluster(struct mddev *mddev, int nodes);
 662 extern void md_cluster_stop(struct mddev *mddev);
 663 extern struct md_thread *md_register_thread(
 664         void (*run)(struct md_thread *thread),
 665         struct mddev *mddev,
 666         const char *name);
 667 extern void md_unregister_thread(struct md_thread **threadp);
 668 extern void md_wakeup_thread(struct md_thread *thread);
 669 extern void md_check_recovery(struct mddev *mddev);
 670 extern void md_reap_sync_thread(struct mddev *mddev);
 671 extern int mddev_init_writes_pending(struct mddev *mddev);
 672 extern bool md_write_start(struct mddev *mddev, struct bio *bi);
 673 extern void md_write_inc(struct mddev *mddev, struct bio *bi);
 674 extern void md_write_end(struct mddev *mddev);
 675 extern void md_done_sync(struct mddev *mddev, int blocks, int ok);
 676 extern void md_error(struct mddev *mddev, struct md_rdev *rdev);
 677 extern void md_finish_reshape(struct mddev *mddev);
 678
 679 extern int mddev_congested(struct mddev *mddev, int bits);
 680 extern void md_flush_request(struct mddev *mddev, struct bio *bio);
 681 extern void md_super_write(struct mddev *mddev, struct md_rdev *rdev,
 682                            sector_t sector, int size, struct page *page);
 683 extern int md_super_wait(struct mddev *mddev);
 684 extern int sync_page_io(struct md_rdev *rdev, sector_t sector, int size,
 685                         struct page *page, int op, int op_flags,
 686                         bool metadata_op);
 687 extern void md_do_sync(struct md_thread *thread);
 688 extern void md_new_event(struct mddev *mddev);
 689 extern void md_allow_write(struct mddev *mddev);
 690 extern void md_wait_for_blocked_rdev(struct md_rdev *rdev, struct mddev *mddev);
 691 extern void md_set_array_sectors(struct mddev *mddev, sector_t array_sectors);
 692 extern int md_check_no_bitmap(struct mddev *mddev);
 693 extern int md_integrity_register(struct mddev *mddev);
 694 extern int md_integrity_add_rdev(struct md_rdev *rdev, struct mddev *mddev);
 695 extern int strict_strtoul_scaled(const char *cp, unsigned long *res, int scale);
 696
 697 extern void mddev_init(struct mddev *mddev);
 698 extern int md_run(struct mddev *mddev);
 699 extern int md_start(struct mddev *mddev);
 700 extern void md_stop(struct mddev *mddev);
 701 extern void md_stop_writes(struct mddev *mddev);
 702 extern int md_rdev_init(struct md_rdev *rdev);
 703 extern void md_rdev_clear(struct md_rdev *rdev);
 704
 705 extern void md_handle_request(struct mddev *mddev, struct bio *bio);
 706 extern void mddev_suspend(struct mddev *mddev);
 707 extern void mddev_resume(struct mddev *mddev);
 708 extern struct bio *bio_alloc_mddev(gfp_t gfp_mask, int nr_iovecs,
 709                                    struct mddev *mddev);
 710
 711 extern void md_reload_sb(struct mddev *mddev, int raid_disk);
 712 extern void md_update_sb(struct mddev *mddev, int force);
 713 extern void md_kick_rdev_from_array(struct md_rdev * rdev);
 714 struct md_rdev *md_find_rdev_nr_rcu(struct mddev *mddev, int nr);
 715 struct md_rdev *md_find_rdev_rcu(struct mddev *mddev, dev_t dev);
 716
 717 static inline void rdev_dec_pending(struct md_rdev *rdev, struct mddev *mddev)
 718 {
 719         int faulty = test_bit(Faulty, &rdev->flags);
 720         if (atomic_dec_and_test(&rdev->nr_pending) && faulty) {
 721                 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
 722                 md_wakeup_thread(mddev->thread);
 723         }
 724 }
 725
 726 extern struct md_cluster_operations *md_cluster_ops;
 727 static inline int mddev_is_clustered(struct mddev *mddev)
 728 {
 729         return mddev->cluster_info && mddev->bitmap_info.nodes > 1;
 730 }
 731
 732 /* clear unsupported mddev_flags */
 733 static inline void mddev_clear_unsupported_flags(struct mddev *mddev,
 734         unsigned long unsupported_flags)
 735 {
 736         mddev->flags &= ~unsupported_flags;
 737 }
 738
 739 static inline void mddev_check_writesame(struct mddev *mddev, struct bio *bio)
 740 {
 741         if (bio_op(bio) == REQ_OP_WRITE_SAME &&
 742             !bio->bi_disk->queue->limits.max_write_same_sectors)
 743                 mddev->queue->limits.max_write_same_sectors = 0;
 744 }
 745
 746 static inline void mddev_check_write_zeroes(struct mddev *mddev, struct bio *bio)
 747 {
 748         if (bio_op(bio) == REQ_OP_WRITE_ZEROES &&
 749             !bio->bi_disk->queue->limits.max_write_zeroes_sectors)
 750                 mddev->queue->limits.max_write_zeroes_sectors = 0;
 751 }
 752 #endif /* _MD_MD_H */