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- /*
- * Copyright (C) 2009-2011 Red Hat, Inc.
- *
- * Author: Mikulas Patocka <[email protected]>
- *
- * This file is released under the GPL.
- */
- #ifndef _LINUX_DM_BUFIO_H
- #define _LINUX_DM_BUFIO_H
- #include <linux/blkdev.h>
- #include <linux/types.h>
- /*----------------------------------------------------------------*/
- struct dm_bufio_client;
- struct dm_buffer;
- /*
- * Flags for dm_bufio_client_create
- */
- #define DM_BUFIO_CLIENT_NO_SLEEP 0x1
- /*
- * Create a buffered IO cache on a given device
- */
- struct dm_bufio_client *
- dm_bufio_client_create(struct block_device *bdev, unsigned int block_size,
- unsigned int reserved_buffers, unsigned int aux_size,
- void (*alloc_callback)(struct dm_buffer *),
- void (*write_callback)(struct dm_buffer *),
- unsigned int flags);
- /*
- * Release a buffered IO cache.
- */
- void dm_bufio_client_destroy(struct dm_bufio_client *c);
- /*
- * Set the sector range.
- * When this function is called, there must be no I/O in progress on the bufio
- * client.
- */
- void dm_bufio_set_sector_offset(struct dm_bufio_client *c, sector_t start);
- /*
- * WARNING: to avoid deadlocks, these conditions are observed:
- *
- * - At most one thread can hold at most "reserved_buffers" simultaneously.
- * - Each other threads can hold at most one buffer.
- * - Threads which call only dm_bufio_get can hold unlimited number of
- * buffers.
- */
- /*
- * Read a given block from disk. Returns pointer to data. Returns a
- * pointer to dm_buffer that can be used to release the buffer or to make
- * it dirty.
- */
- void *dm_bufio_read(struct dm_bufio_client *c, sector_t block,
- struct dm_buffer **bp);
- /*
- * Like dm_bufio_read, but return buffer from cache, don't read
- * it. If the buffer is not in the cache, return NULL.
- */
- void *dm_bufio_get(struct dm_bufio_client *c, sector_t block,
- struct dm_buffer **bp);
- /*
- * Like dm_bufio_read, but don't read anything from the disk. It is
- * expected that the caller initializes the buffer and marks it dirty.
- */
- void *dm_bufio_new(struct dm_bufio_client *c, sector_t block,
- struct dm_buffer **bp);
- /*
- * Prefetch the specified blocks to the cache.
- * The function starts to read the blocks and returns without waiting for
- * I/O to finish.
- */
- void dm_bufio_prefetch(struct dm_bufio_client *c,
- sector_t block, unsigned int n_blocks);
- /*
- * Release a reference obtained with dm_bufio_{read,get,new}. The data
- * pointer and dm_buffer pointer is no longer valid after this call.
- */
- void dm_bufio_release(struct dm_buffer *b);
- /*
- * Mark a buffer dirty. It should be called after the buffer is modified.
- *
- * In case of memory pressure, the buffer may be written after
- * dm_bufio_mark_buffer_dirty, but before dm_bufio_write_dirty_buffers. So
- * dm_bufio_write_dirty_buffers guarantees that the buffer is on-disk but
- * the actual writing may occur earlier.
- */
- void dm_bufio_mark_buffer_dirty(struct dm_buffer *b);
- /*
- * Mark a part of the buffer dirty.
- *
- * The specified part of the buffer is scheduled to be written. dm-bufio may
- * write the specified part of the buffer or it may write a larger superset.
- */
- void dm_bufio_mark_partial_buffer_dirty(struct dm_buffer *b,
- unsigned int start, unsigned int end);
- /*
- * Initiate writing of dirty buffers, without waiting for completion.
- */
- void dm_bufio_write_dirty_buffers_async(struct dm_bufio_client *c);
- /*
- * Write all dirty buffers. Guarantees that all dirty buffers created prior
- * to this call are on disk when this call exits.
- */
- int dm_bufio_write_dirty_buffers(struct dm_bufio_client *c);
- /*
- * Send an empty write barrier to the device to flush hardware disk cache.
- */
- int dm_bufio_issue_flush(struct dm_bufio_client *c);
- /*
- * Send a discard request to the underlying device.
- */
- int dm_bufio_issue_discard(struct dm_bufio_client *c, sector_t block, sector_t count);
- /*
- * Like dm_bufio_release but also move the buffer to the new
- * block. dm_bufio_write_dirty_buffers is needed to commit the new block.
- */
- void dm_bufio_release_move(struct dm_buffer *b, sector_t new_block);
- /*
- * Free the given buffer.
- * This is just a hint, if the buffer is in use or dirty, this function
- * does nothing.
- */
- void dm_bufio_forget(struct dm_bufio_client *c, sector_t block);
- /*
- * Free the given range of buffers.
- * This is just a hint, if the buffer is in use or dirty, this function
- * does nothing.
- */
- void dm_bufio_forget_buffers(struct dm_bufio_client *c, sector_t block, sector_t n_blocks);
- /*
- * Set the minimum number of buffers before cleanup happens.
- */
- void dm_bufio_set_minimum_buffers(struct dm_bufio_client *c, unsigned int n);
- unsigned int dm_bufio_get_block_size(struct dm_bufio_client *c);
- sector_t dm_bufio_get_device_size(struct dm_bufio_client *c);
- struct dm_io_client *dm_bufio_get_dm_io_client(struct dm_bufio_client *c);
- sector_t dm_bufio_get_block_number(struct dm_buffer *b);
- void *dm_bufio_get_block_data(struct dm_buffer *b);
- void *dm_bufio_get_aux_data(struct dm_buffer *b);
- struct dm_bufio_client *dm_bufio_get_client(struct dm_buffer *b);
- /*----------------------------------------------------------------*/
- #endif
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