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| author | Jens Axboe <axboe@kernel.dk> | 2025-02-04 21:39:59 +0300 |
|---|---|---|
| committer | Christian Brauner <brauner@kernel.org> | 2025-02-27 13:27:54 +0300 |
| commit | b2cd5ae693a3dc5b70a0f75fba96452c591a2047 (patch) | |
| tree | 25b804163b8aed706ff059a39eccc22c1a8bd95a | |
| parent | 2014c95afecee3e76ca4a56956a936e23283f05b (diff) | |
| download | linux-b2cd5ae693a3dc5b70a0f75fba96452c591a2047.tar.xz | |
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>
| -rw-r--r-- | Documentation/filesystems/iomap/design.rst | 5 | ||||
| -rw-r--r-- | Documentation/filesystems/iomap/operations.rst | 2 | ||||
| -rw-r--r-- | fs/iomap/buffered-io.c | 4 | ||||
| -rw-r--r-- | include/linux/iomap.h | 1 |
4 files changed, 12 insertions, 0 deletions
diff --git a/Documentation/filesystems/iomap/design.rst b/Documentation/filesystems/iomap/design.rst index b0d0188a095e..7b91546750f5 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 2c7f5df9d8b0..584ff549f9a6 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 ------------------------ diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c index d303e6c8900c..ea863c3cf510 100644 --- a/fs/iomap/buffered-io.c +++ b/fs/iomap/buffered-io.c @@ -603,6 +603,8 @@ struct folio *iomap_get_folio(struct iomap_iter *iter, loff_t pos, size_t len) if (iter->flags & IOMAP_NOWAIT) fgp |= FGP_NOWAIT; + if (iter->flags & IOMAP_DONTCACHE) + fgp |= FGP_DONTCACHE; fgp |= fgf_set_order(len); return __filemap_get_folio(iter->inode->i_mapping, pos >> PAGE_SHIFT, @@ -1034,6 +1036,8 @@ iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *i, if (iocb->ki_flags & IOCB_NOWAIT) iter.flags |= IOMAP_NOWAIT; + if (iocb->ki_flags & IOCB_DONTCACHE) + iter.flags |= IOMAP_DONTCACHE; while ((ret = iomap_iter(&iter, ops)) > 0) iter.processed = iomap_write_iter(&iter, i); diff --git a/include/linux/iomap.h b/include/linux/iomap.h index 75bf54e76f3b..26b0dbe23e62 100644 --- a/include/linux/iomap.h +++ b/include/linux/iomap.h @@ -183,6 +183,7 @@ struct iomap_folio_ops { #define IOMAP_DAX 0 #endif /* CONFIG_FS_DAX */ #define IOMAP_ATOMIC (1 << 9) +#define IOMAP_DONTCACHE (1 << 10) struct iomap_ops { /* |