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Diffstat (limited to 'Documentation/filesystems/netfs_library.rst')
| -rw-r--r-- | Documentation/filesystems/netfs_library.rst | 23 |
1 files changed, 4 insertions, 19 deletions
diff --git a/Documentation/filesystems/netfs_library.rst b/Documentation/filesystems/netfs_library.rst index 48b95d04f7..4cc657d743 100644 --- a/Documentation/filesystems/netfs_library.rst +++ b/Documentation/filesystems/netfs_library.rst @@ -295,7 +295,6 @@ through which it can issue requests and negotiate:: struct netfs_request_ops { void (*init_request)(struct netfs_io_request *rreq, struct file *file); void (*free_request)(struct netfs_io_request *rreq); - int (*begin_cache_operation)(struct netfs_io_request *rreq); void (*expand_readahead)(struct netfs_io_request *rreq); bool (*clamp_length)(struct netfs_io_subrequest *subreq); void (*issue_read)(struct netfs_io_subrequest *subreq); @@ -317,20 +316,6 @@ The operations are as follows: [Optional] This is called as the request is being deallocated so that the filesystem can clean up any state it has attached there. - * ``begin_cache_operation()`` - - [Optional] This is called to ask the network filesystem to call into the - cache (if present) to initialise the caching state for this read. The netfs - library module cannot access the cache directly, so the cache should call - something like fscache_begin_read_operation() to do this. - - The cache gets to store its state in ->cache_resources and must set a table - of operations of its own there (though of a different type). - - This should return 0 on success and an error code otherwise. If an error is - reported, the operation may proceed anyway, just without local caching (only - out of memory and interruption errors cause failure here). - * ``expand_readahead()`` [Optional] This is called to allow the filesystem to expand the size of a @@ -460,14 +445,14 @@ When implementing a local cache to be used by the read helpers, two things are required: some way for the network filesystem to initialise the caching for a read request and a table of operations for the helpers to call. -The network filesystem's ->begin_cache_operation() method is called to set up a -cache and this must call into the cache to do the work. If using fscache, for -example, the cache would call:: +To begin a cache operation on an fscache object, the following function is +called:: int fscache_begin_read_operation(struct netfs_io_request *rreq, struct fscache_cookie *cookie); -passing in the request pointer and the cookie corresponding to the file. +passing in the request pointer and the cookie corresponding to the file. This +fills in the cache resources mentioned below. The netfs_io_request object contains a place for the cache to hang its state:: |