diff options
| author | Jens Axboe <axboe@kernel.dk> | 2025-02-04 11:39:59 -0700 |
|---|---|---|
| committer | Christian Brauner <brauner@kernel.org> | 2025-02-27 11:27:54 +0100 |
| commit | b2cd5ae693a3dc5b70a0f75fba96452c591a2047 (patch) | |
| tree | 25b804163b8aed706ff059a39eccc22c1a8bd95a /Documentation/filesystems | |
| parent | 2014c95afecee3e76ca4a56956a936e23283f05b (diff) | |
iomap: make buffered writes work with RWF_DONTCACHE
Add iomap buffered write support for RWF_DONTCACHE. If RWF_DONTCACHE is
set for a write, mark the folios being written as uncached. Then
writeback completion will drop the pages. The write_iter handler simply
kicks off writeback for the pages, and writeback completion will take
care of the rest.
Signed-off-by: "Darrick J. Wong" <djwong@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Link: https://lore.kernel.org/r/20250204184047.356762-2-axboe@kernel.dk
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Diffstat (limited to 'Documentation/filesystems')
| -rw-r--r-- | Documentation/filesystems/iomap/design.rst | 5 | ||||
| -rw-r--r-- | Documentation/filesystems/iomap/operations.rst | 2 |
2 files changed, 7 insertions, 0 deletions
diff --git a/Documentation/filesystems/iomap/design.rst b/Documentation/filesystems/iomap/design.rst index b0d0188a095e5..7b91546750f59 100644 --- a/Documentation/filesystems/iomap/design.rst +++ b/Documentation/filesystems/iomap/design.rst @@ -352,6 +352,11 @@ operations: ``IOMAP_NOWAIT`` is often set on behalf of ``IOCB_NOWAIT`` or ``RWF_NOWAIT``. + * ``IOMAP_DONTCACHE`` is set when the caller wishes to perform a + buffered file I/O and would like the kernel to drop the pagecache + after the I/O completes, if it isn't already being used by another + thread. + If it is necessary to read existing file contents from a `different <https://lore.kernel.org/all/20191008071527.29304-9-hch@lst.de/>`_ device or address range on a device, the filesystem should return that diff --git a/Documentation/filesystems/iomap/operations.rst b/Documentation/filesystems/iomap/operations.rst index 2c7f5df9d8b03..584ff549f9a65 100644 --- a/Documentation/filesystems/iomap/operations.rst +++ b/Documentation/filesystems/iomap/operations.rst @@ -131,6 +131,8 @@ These ``struct kiocb`` flags are significant for buffered I/O with iomap: * ``IOCB_NOWAIT``: Turns on ``IOMAP_NOWAIT``. + * ``IOCB_DONTCACHE``: Turns on ``IOMAP_DONTCACHE``. + Internal per-Folio State ------------------------ |