2 * Copyright (C) 2009-2011 Red Hat, Inc.
4 * Author: Mikulas Patocka <mpatocka@redhat.com>
6 * This file is released under the GPL.
12 #include <linux/blkdev.h>
13 #include <linux/types.h>
15 /*----------------------------------------------------------------*/
17 struct dm_bufio_client;
21 * Create a buffered IO cache on a given device
23 struct dm_bufio_client *
24 dm_bufio_client_create(struct block_device *bdev, unsigned block_size,
25 unsigned reserved_buffers, unsigned aux_size,
26 void (*alloc_callback)(struct dm_buffer *),
27 void (*write_callback)(struct dm_buffer *));
30 * Release a buffered IO cache.
32 void dm_bufio_client_destroy(struct dm_bufio_client *c);
35 * WARNING: to avoid deadlocks, these conditions are observed:
37 * - At most one thread can hold at most "reserved_buffers" simultaneously.
38 * - Each other threads can hold at most one buffer.
39 * - Threads which call only dm_bufio_get can hold unlimited number of
44 * Read a given block from disk. Returns pointer to data. Returns a
45 * pointer to dm_buffer that can be used to release the buffer or to make
48 void *dm_bufio_read(struct dm_bufio_client *c, sector_t block,
49 struct dm_buffer **bp);
52 * Like dm_bufio_read, but return buffer from cache, don't read
53 * it. If the buffer is not in the cache, return NULL.
55 void *dm_bufio_get(struct dm_bufio_client *c, sector_t block,
56 struct dm_buffer **bp);
59 * Like dm_bufio_read, but don't read anything from the disk. It is
60 * expected that the caller initializes the buffer and marks it dirty.
62 void *dm_bufio_new(struct dm_bufio_client *c, sector_t block,
63 struct dm_buffer **bp);
66 * Release a reference obtained with dm_bufio_{read,get,new}. The data
67 * pointer and dm_buffer pointer is no longer valid after this call.
69 void dm_bufio_release(struct dm_buffer *b);
72 * Mark a buffer dirty. It should be called after the buffer is modified.
74 * In case of memory pressure, the buffer may be written after
75 * dm_bufio_mark_buffer_dirty, but before dm_bufio_write_dirty_buffers. So
76 * dm_bufio_write_dirty_buffers guarantees that the buffer is on-disk but
77 * the actual writing may occur earlier.
79 void dm_bufio_mark_buffer_dirty(struct dm_buffer *b);
82 * Initiate writing of dirty buffers, without waiting for completion.
84 void dm_bufio_write_dirty_buffers_async(struct dm_bufio_client *c);
87 * Write all dirty buffers. Guarantees that all dirty buffers created prior
88 * to this call are on disk when this call exits.
90 int dm_bufio_write_dirty_buffers(struct dm_bufio_client *c);
93 * Send an empty write barrier to the device to flush hardware disk cache.
95 int dm_bufio_issue_flush(struct dm_bufio_client *c);
98 * Like dm_bufio_release but also move the buffer to the new
99 * block. dm_bufio_write_dirty_buffers is needed to commit the new block.
101 void dm_bufio_release_move(struct dm_buffer *b, sector_t new_block);
103 unsigned dm_bufio_get_block_size(struct dm_bufio_client *c);
104 sector_t dm_bufio_get_device_size(struct dm_bufio_client *c);
105 sector_t dm_bufio_get_block_number(struct dm_buffer *b);
106 void *dm_bufio_get_block_data(struct dm_buffer *b);
107 void *dm_bufio_get_aux_data(struct dm_buffer *b);
108 struct dm_bufio_client *dm_bufio_get_client(struct dm_buffer *b);
110 /*----------------------------------------------------------------*/