filesystems/caching/netfs-api.rst

4 Network Filesystem Caching API
7 Fscache provides an API by which a network filesystem can make use of local
45 The fscache hierarchy is organised on two levels from a network filesystem's
50 A network filesystem acquires a volume cookie for a volume using a volume key,
58 A filesystem would typically have a volume cookie for each superblock.
60 The filesystem then acquires a cookie for each file within that volume using an
65 filesystem.
67 A filesystem would typically have a cookie for each inode, and would acquire it
70 Once it has a cookie, the filesystem needs to mark the cookie as being in use.
75 A filesystem would typically "use" the cookie in its file open routine and
81 When performing a read, write or resize on a cookie, the filesystem must first
87 The filesystem is expected to use netfslib to access the cache, but that's not
94 The first step for a network filesystem is to acquire a volume cookie for the
107 should begin with the name of the filesystem and should be no longer than 254
128 When the network filesystem has finished with a volume, it should relinquish it
145 Once it has a volume cookie, a network filesystem can use it to acquire a
178 When the network filesystem has finished with a cookie, it should relinquish it
191 Once a cookie has been acquired by a network filesystem, the filesystem should
207 The *unuse* function indicates that a filesystem has finished using a cookie.
225 If a network filesystem file is resized locally by truncation, the following
306 Typically this will be necessary when the server informs the network filesystem
307 of a remote third-party change - at which point the filesystem has to throw
331 To write data to the cache from network filesystem writeback, the cache
357 The *set* function is intended to be called from the filesystem's
362 The *unpin* function is intended to be called from the filesystem's
376 If a network filesystem has locally modified data that it wants to write to the
414 but it does have to align to DIO boundaries on the backing filesystem).  The