| /* |
| * Copyright (C) 2009-2011 Red Hat, Inc. |
| * |
| * Author: Mikulas Patocka <mpatocka@redhat.com> |
| * |
| * 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; |
| |
| /* |
| * Create a buffered IO cache on a given device |
| */ |
| struct dm_bufio_client * |
| dm_bufio_client_create(struct block_device *bdev, unsigned block_size, |
| unsigned reserved_buffers, unsigned aux_size, |
| void (*alloc_callback)(struct dm_buffer *), |
| void (*write_callback)(struct dm_buffer *)); |
| |
| /* |
| * 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 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 start, unsigned 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 n); |
| |
| unsigned 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 |