Files
haiku-beta6/headers/os/drivers/fs_cache.h
T
Axel Dörfler 3d268eda3d * Extracted file_map API out of the file cache - it's now an optional service
that can be used by file systems.
* Changed the way the file cache works: instead of reading/writing to the
  underlying device directly, it can now be used for any data source, ie.
  also network file systems.
* As a result, the former pages_io() moved to the VFS layer, and can now be
  called by a file system via {read|write}_file_io_vec_pages() (naming
  suggestions are always welcomed :-)). It now gets an FD, and uses that to
  communicate with the device (via its fs_{read|write}_pages() hooks).
* The file_cache_{read|write}() functions must now be called without holding
  an I/O relevant file system lock. That allows the file cache to prepare the
  pages without colliding with the page writer, IOW the "mayBlock" flag can
  go into the attic again (yay!).
* This also results in a much better performance when the system does I/O and
  is low on memory, as the page writer can now finally write back some pages,
  and that even without maxing out the CPU :)
* The API changes put slightly more burden on the fs_{read|write}_pages()
  hooks, but in combination with the file_map it's still pretty straight
  forward. It just will have to dispatch the call to the underlying device
  directly, usually it will just call its fs_{read|write}_pages() hooks
  via the above mentioned calls.
* Ported BFS and FAT to the new API, the latter has not been tested, though.
* Also ported the API changes to the fs_shell. I also completely removed its
  file cache level page handling - the downside is that device access is no
  longer cached (ie. depends on the host OS now), the upside is that the code
  is greatly simplified.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@22886 a95241bf-73f2-0310-859d-f6bbb57e9c96
2007-11-10 21:19:52 +00:00

82 lines
3.1 KiB
C

/*
* Copyright 2004-2007, Haiku Inc. All Rights Reserved.
* Distributed under the terms of the MIT License.
*/
#ifndef _FS_CACHE_H
#define _FS_CACHE_H
/*! File System File and Block Caches */
#include <fs_interface.h>
typedef void (*transaction_notification_hook)(int32 id, void *data);
#ifdef __cplusplus
extern "C" {
#endif
/* transactions */
extern int32 cache_start_transaction(void *_cache);
extern status_t cache_sync_transaction(void *_cache, int32 id);
extern status_t cache_end_transaction(void *_cache, int32 id,
transaction_notification_hook hook, void *data);
extern status_t cache_abort_transaction(void *_cache, int32 id);
extern int32 cache_detach_sub_transaction(void *_cache, int32 id,
transaction_notification_hook hook, void *data);
extern status_t cache_abort_sub_transaction(void *_cache, int32 id);
extern status_t cache_start_sub_transaction(void *_cache, int32 id);
extern status_t cache_next_block_in_transaction(void *_cache, int32 id,
uint32 *_cookie, off_t *_blockNumber, void **_data,
void **_unchangedData);
extern int32 cache_blocks_in_transaction(void *_cache, int32 id);
extern int32 cache_blocks_in_sub_transaction(void *_cache, int32 id);
/* block cache */
extern void block_cache_delete(void *_cache, bool allowWrites);
extern void *block_cache_create(int fd, off_t numBlocks, size_t blockSize,
bool readOnly);
extern status_t block_cache_sync(void *_cache);
extern status_t block_cache_sync_etc(void *_cache, off_t blockNumber,
size_t numBlocks);
extern status_t block_cache_make_writable(void *_cache, off_t blockNumber,
int32 transaction);
extern void *block_cache_get_writable_etc(void *_cache, off_t blockNumber,
off_t base, off_t length, int32 transaction);
extern void *block_cache_get_writable(void *_cache, off_t blockNumber,
int32 transaction);
extern void *block_cache_get_empty(void *_cache, off_t blockNumber,
int32 transaction);
extern const void *block_cache_get_etc(void *_cache, off_t blockNumber,
off_t base, off_t length);
extern const void *block_cache_get(void *_cache, off_t blockNumber);
extern status_t block_cache_set_dirty(void *_cache, off_t blockNumber,
bool isDirty, int32 transaction);
extern void block_cache_put(void *_cache, off_t blockNumber);
/* file cache */
extern void *file_cache_create(dev_t mountID, ino_t vnodeID, off_t size);
extern void file_cache_delete(void *_cacheRef);
extern status_t file_cache_set_size(void *_cacheRef, off_t size);
extern status_t file_cache_sync(void *_cache);
extern status_t file_cache_read(void *_cacheRef, void *cookie, off_t offset,
void *bufferBase, size_t *_size);
extern status_t file_cache_write(void *_cacheRef, void *cookie, off_t offset,
const void *buffer, size_t *_size);
/* file map */
extern void *file_map_create(dev_t mountID, ino_t vnodeID);
extern void file_map_delete(void *_map);
extern void file_map_set_size(void *_map, off_t size);
extern void file_map_invalidate(void *_map, off_t offset, off_t size);
extern status_t file_map_translate(void *_map, off_t offset, size_t size,
struct file_io_vec *vecs, size_t *_count);
#ifdef __cplusplus
}
#endif
#endif /* _FS_CACHE_H */