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/*
 13 * version 3 is host-endian order, this is deprecated and not used for new
 14 * array
 15 */
 16#define BITMAP_MAJOR_LO		3
 17#define BITMAP_MAJOR_HOSTENDIAN	3
 18/* version 4 is little-endian order, the default value */
 19#define BITMAP_MAJOR_HI		4
 20/* version 5 is only used for cluster */
 21#define BITMAP_MAJOR_CLUSTERED	5
 22/* version 6 is only used for lockless bitmap */
 23#define BITMAP_MAJOR_LOCKLESS	6
 24
 25/* use these for bitmap->flags and bitmap->sb->state bit-fields */
 26enum bitmap_state {
 27	BITMAP_STALE	   = 1, /* the bitmap file is out of date or had -EIO */
 28	BITMAP_WRITE_ERROR = 2, /* A write error has occurred */
 29	BITMAP_FIRST_USE   = 3, /* llbitmap is just created */
 30	BITMAP_CLEAN       = 4, /* llbitmap is created with assume_clean */
 31	BITMAP_DAEMON_BUSY = 5, /* llbitmap daemon is not finished after daemon_sleep */
 32	BITMAP_HOSTENDIAN  =15,
 33};
 34
 35/* the superblock at the front of the bitmap file -- little endian */
 36typedef struct bitmap_super_s {
 37	__le32 magic;        /*  0  BITMAP_MAGIC */
 38	__le32 version;      /*  4  the bitmap major for now, could change... */
 39	__u8  uuid[16];      /*  8  128 bit uuid - must match md device uuid */
 40	__le64 events;       /* 24  event counter for the bitmap (1)*/
 41	__le64 events_cleared;/*32  event counter when last bit cleared (2) */
 42	__le64 sync_size;    /* 40  the size of the md device's sync range(3) */
 43	__le32 state;        /* 48  bitmap state information */
 44	__le32 chunksize;    /* 52  the bitmap chunk size in bytes */
 45	__le32 daemon_sleep; /* 56  seconds between disk flushes */
 46	__le32 write_behind; /* 60  number of outstanding write-behind writes */
 47	__le32 sectors_reserved; /* 64 number of 512-byte sectors that are
 48				  * reserved for the bitmap. */
 49	__le32 nodes;        /* 68 the maximum number of nodes in cluster. */
 50	__u8 cluster_name[64]; /* 72 cluster name to which this md belongs */
 51	__u8  pad[256 - 136]; /* set to zero */
 52} bitmap_super_t;
 53
 54/* notes:
 55 * (1) This event counter is updated before the eventcounter in the md superblock
 56 *    When a bitmap is loaded, it is only accepted if this event counter is equal
 57 *    to, or one greater than, the event counter in the superblock.
 58 * (2) This event counter is updated when the other one is *if*and*only*if* the
 59 *    array is not degraded.  As bits are not cleared when the array is degraded,
 60 *    this represents the last time that any bits were cleared.
 61 *    If a device is being added that has an event count with this value or
 62 *    higher, it is accepted as conforming to the bitmap.
 63 * (3)This is the number of sectors represented by the bitmap, and is the range that
 64 *    resync happens across.  For raid1 and raid5/6 it is the size of individual
 65 *    devices.  For raid10 it is the size of the array.
 66 */
 67
 68struct md_bitmap_stats {
 69	u64		events_cleared;
 70	int		behind_writes;
 71	bool		behind_wait;
 72
 73	unsigned long	missing_pages;
 74	unsigned long	file_pages;
 75	unsigned long	sync_size;
 76	unsigned long	pages;
 77	struct file	*file;
 78};
 79
 80typedef void (md_bitmap_fn)(struct mddev *mddev, sector_t offset,
 81			    unsigned long sectors);
 82
 83struct bitmap_operations {
 84	struct md_submodule_head head;
 85
 86	bool (*enabled)(void *data, bool flush);
 87	int (*create)(struct mddev *mddev);
 88	int (*resize)(struct mddev *mddev, sector_t blocks, int chunksize);
 89
 90	int (*load)(struct mddev *mddev);
 91	void (*destroy)(struct mddev *mddev);
 92	void (*flush)(struct mddev *mddev);
 93	void (*write_all)(struct mddev *mddev);
 94	void (*dirty_bits)(struct mddev *mddev, unsigned long s,
 95			   unsigned long e);
 96	void (*unplug)(struct mddev *mddev, bool sync);
 97	void (*daemon_work)(struct mddev *mddev);
 98
 99	void (*start_behind_write)(struct mddev *mddev);
100	void (*end_behind_write)(struct mddev *mddev);
101	void (*wait_behind_writes)(struct mddev *mddev);
102
103	md_bitmap_fn *start_write;
104	md_bitmap_fn *end_write;
105	md_bitmap_fn *start_discard;
106	md_bitmap_fn *end_discard;
107
108	sector_t (*skip_sync_blocks)(struct mddev *mddev, sector_t offset);
109	bool (*blocks_synced)(struct mddev *mddev, sector_t offset);
110	bool (*start_sync)(struct mddev *mddev, sector_t offset,
111			   sector_t *blocks, bool degraded);
112	void (*end_sync)(struct mddev *mddev, sector_t offset, sector_t *blocks);
113	void (*cond_end_sync)(struct mddev *mddev, sector_t sector, bool force);
114	void (*close_sync)(struct mddev *mddev);
115
116	void (*update_sb)(void *data);
117	int (*get_stats)(void *data, struct md_bitmap_stats *stats);
118
119	void (*sync_with_cluster)(struct mddev *mddev,
120				  sector_t old_lo, sector_t old_hi,
121				  sector_t new_lo, sector_t new_hi);
122	void *(*get_from_slot)(struct mddev *mddev, int slot);
123	int (*copy_from_slot)(struct mddev *mddev, int slot, sector_t *lo,
124			      sector_t *hi, bool clear_bits);
125	void (*set_pages)(void *data, unsigned long pages);
126	void (*free)(void *data);
127
128	struct attribute_group *group;
129};
130
131/* the bitmap API */
132static inline bool md_bitmap_registered(struct mddev *mddev)
133{
134	return mddev->bitmap_ops != NULL;
135}
136
137static inline bool md_bitmap_enabled(struct mddev *mddev, bool flush)
138{
139	/* bitmap_ops must be registered before creating bitmap. */
140	if (!md_bitmap_registered(mddev))
141		return false;
142
143	if (!mddev->bitmap)
144		return false;
145
146	return mddev->bitmap_ops->enabled(mddev->bitmap, flush);
147}
148
149static inline bool md_bitmap_start_sync(struct mddev *mddev, sector_t offset,
150					sector_t *blocks, bool degraded)
151{
152	/* always resync if no bitmap */
153	if (!md_bitmap_enabled(mddev, false)) {
154		*blocks = 1024;
155		return true;
156	}
157
158	return mddev->bitmap_ops->start_sync(mddev, offset, blocks, degraded);
159}
160
161static inline void md_bitmap_end_sync(struct mddev *mddev, sector_t offset,
162				      sector_t *blocks)
163{
164	if (!md_bitmap_enabled(mddev, false)) {
165		*blocks = 1024;
166		return;
167	}
168
169	mddev->bitmap_ops->end_sync(mddev, offset, blocks);
170}
171
172#ifdef CONFIG_MD_BITMAP
173int md_bitmap_init(void);
174void md_bitmap_exit(void);
175#else
176static inline int md_bitmap_init(void)
177{
178	return 0;
179}
180static inline void md_bitmap_exit(void)
181{
182}
183#endif
184
185#ifdef CONFIG_MD_LLBITMAP
186int md_llbitmap_init(void);
187void md_llbitmap_exit(void);
188#else
189static inline int md_llbitmap_init(void)
190{
191	return 0;
192}
193static inline void md_llbitmap_exit(void)
194{
195}
196#endif
197
198#endif