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
 12typedef __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 */
 22enum 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 23	BITMAP_STALE	   = 1,  /* the bitmap file is out of date or had -EIO */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 */
 29typedef 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
 61struct 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
 73struct 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
 88	void (*start_behind_write)(struct mddev *mddev);
 89	void (*end_behind_write)(struct mddev *mddev);
 90	void (*wait_behind_writes)(struct mddev *mddev);
 91
 92	int (*startwrite)(struct mddev *mddev, sector_t offset,
 93			  unsigned long sectors);
 94	void (*endwrite)(struct mddev *mddev, sector_t offset,
 95			 unsigned long sectors);
 96	bool (*start_sync)(struct mddev *mddev, sector_t offset,
 97			   sector_t *blocks, bool degraded);
 98	void (*end_sync)(struct mddev *mddev, sector_t offset, sector_t *blocks);
 99	void (*cond_end_sync)(struct mddev *mddev, sector_t sector, bool force);
100	void (*close_sync)(struct mddev *mddev);
101
102	void (*update_sb)(void *data);
103	int (*get_stats)(void *data, struct md_bitmap_stats *stats);
104
105	void (*sync_with_cluster)(struct mddev *mddev,
106				  sector_t old_lo, sector_t old_hi,
107				  sector_t new_lo, sector_t new_hi);
108	void *(*get_from_slot)(struct mddev *mddev, int slot);
109	int (*copy_from_slot)(struct mddev *mddev, int slot, sector_t *lo,
110			      sector_t *hi, bool clear_bits);
111	void (*set_pages)(void *data, unsigned long pages);
112	void (*free)(void *data);
113};
114
115/* the bitmap API */
116void mddev_set_bitmap_ops(struct mddev *mddev);
117
118#endif