drivers/md/md-bitmap.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3  * bitmap.h: Copyright (C) Peter T. Breuer (ptb@ot.uc3m.es) 2003
   4  *
   5  * additions: Copyright (C) 2003-2004, Paul Clements, SteelEye Technology, Inc.
   6  */
   7 #ifndef BITMAP_H
   8 #define BITMAP_H 1
   9
  10 #define BITMAP_MAGIC 0x6d746962
  11
  12 typedef __u16 bitmap_counter_t;
  13 #define COUNTER_BITS 16
  14 #define COUNTER_BIT_SHIFT 4
  15 #define COUNTER_BYTE_SHIFT (COUNTER_BIT_SHIFT - 3)
  16
  17 #define NEEDED_MASK ((bitmap_counter_t) (1 << (COUNTER_BITS - 1)))
  18 #define RESYNC_MASK ((bitmap_counter_t) (1 << (COUNTER_BITS - 2)))
  19 #define COUNTER_MAX ((bitmap_counter_t) RESYNC_MASK - 1)
  20
  21 /* use these for bitmap->flags and bitmap->sb->state bit-fields */
  22 enum bitmap_state {
  23         BITMAP_STALE       = 1,  /* the bitmap file is out of date or had -EIO */
  24         BITMAP_WRITE_ERROR = 2, /* A write error has occurred */
  25         BITMAP_HOSTENDIAN  =15,
  26 };
  27
  28 /* the superblock at the front of the bitmap file -- little endian */
  29 typedef struct bitmap_super_s {
  30         __le32 magic;        /*  0  BITMAP_MAGIC */
  31         __le32 version;      /*  4  the bitmap major for now, could change... */
  32         __u8  uuid[16];      /*  8  128 bit uuid - must match md device uuid */
  33         __le64 events;       /* 24  event counter for the bitmap (1)*/
  34         __le64 events_cleared;/*32  event counter when last bit cleared (2) */
  35         __le64 sync_size;    /* 40  the size of the md device's sync range(3) */
  36         __le32 state;        /* 48  bitmap state information */
  37         __le32 chunksize;    /* 52  the bitmap chunk size in bytes */
  38         __le32 daemon_sleep; /* 56  seconds between disk flushes */
  39         __le32 write_behind; /* 60  number of outstanding write-behind writes */
  40         __le32 sectors_reserved; /* 64 number of 512-byte sectors that are
  41                                   * reserved for the bitmap. */
  42         __le32 nodes;        /* 68 the maximum number of nodes in cluster. */
  43         __u8 cluster_name[64]; /* 72 cluster name to which this md belongs */
  44         __u8  pad[256 - 136]; /* set to zero */
  45 } bitmap_super_t;
  46
  47 /* notes:
  48  * (1) This event counter is updated before the eventcounter in the md superblock
  49  *    When a bitmap is loaded, it is only accepted if this event counter is equal
  50  *    to, or one greater than, the event counter in the superblock.
  51  * (2) This event counter is updated when the other one is *if*and*only*if* the
  52  *    array is not degraded.  As bits are not cleared when the array is degraded,
  53  *    this represents the last time that any bits were cleared.
  54  *    If a device is being added that has an event count with this value or
  55  *    higher, it is accepted as conforming to the bitmap.
  56  * (3)This is the number of sectors represented by the bitmap, and is the range that
  57  *    resync happens across.  For raid1 and raid5/6 it is the size of individual
  58  *    devices.  For raid10 it is the size of the array.
  59  */
  60
  61 struct md_bitmap_stats {
  62         u64             events_cleared;
  63         int             behind_writes;
  64         bool            behind_wait;
  65
  66         unsigned long   missing_pages;
  67         unsigned long   file_pages;
  68         unsigned long   sync_size;
  69         unsigned long   pages;
  70         struct file     *file;
  71 };
  72
  73 struct bitmap_operations {
  74         bool (*enabled)(struct mddev *mddev);
  75         int (*create)(struct mddev *mddev, int slot);
  76         int (*resize)(struct mddev *mddev, sector_t blocks, int chunksize,
  77                       bool init);
  78
  79         int (*load)(struct mddev *mddev);
  80         void (*destroy)(struct mddev *mddev);
  81         void (*flush)(struct mddev *mddev);
  82         void (*write_all)(struct mddev *mddev);
  83         void (*dirty_bits)(struct mddev *mddev, unsigned long s,
  84                            unsigned long e);
  85         void (*unplug)(struct mddev *mddev, bool sync);
  86         void (*daemon_work)(struct mddev *mddev);
  87         void (*wait_behind_writes)(struct mddev *mddev);
  88
  89         int (*startwrite)(struct mddev *mddev, sector_t offset,
  90                           unsigned long sectors, bool behind);
  91         void (*endwrite)(struct mddev *mddev, sector_t offset,
  92                          unsigned long sectors, bool success, bool behind);
  93         bool (*start_sync)(struct mddev *mddev, sector_t offset,
  94                            sector_t *blocks, bool degraded);
  95         void (*end_sync)(struct mddev *mddev, sector_t offset, sector_t *blocks);
  96         void (*cond_end_sync)(struct mddev *mddev, sector_t sector, bool force);
  97         void (*close_sync)(struct mddev *mddev);
  98
  99         void (*update_sb)(void *data);
 100         int (*get_stats)(void *data, struct md_bitmap_stats *stats);
 101
 102         void (*sync_with_cluster)(struct mddev *mddev,
 103                                   sector_t old_lo, sector_t old_hi,
 104                                   sector_t new_lo, sector_t new_hi);
 105         void *(*get_from_slot)(struct mddev *mddev, int slot);
 106         int (*copy_from_slot)(struct mddev *mddev, int slot, sector_t *lo,
 107                               sector_t *hi, bool clear_bits);
 108         void (*set_pages)(void *data, unsigned long pages);
 109         void (*free)(void *data);
 110 };
 111
 112 /* the bitmap API */
 113 void mddev_set_bitmap_ops(struct mddev *mddev);
 114
 115 #endif