The iomap_folio_ops are only used for buffered writes, including the zero
and unshare variants. Rename them to iomap_write_ops to better describe
the usage, and pass them through the call chain like the other operation
specific methods instead of through the iomap.
xfs_iomap_valid grows a IOMAP_HOLE check to keep the existing behavior
that never attached the folio_ops to a iomap representing a hole.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/20250710133343.399917-12-hch@lst.de
Acked-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Let's document the use of these flags in iomap design doc where other
flags are defined too -
- IOMAP_F_BOUNDARY was added by XFS to prevent merging of I/O and I/O
completions across RTG boundaries.
- IOMAP_F_ATOMIC_BIO was added for supporting atomic I/O operations
for filesystems to inform the iomap that it needs HW-offload based
mechanism for torn-write protection.
While we are at it, let's also fix the description of IOMAP_F_PRIVATE
flag after a recent:
commit 923936efeb ("iomap: Fix conflicting values of iomap flags")
Signed-off-by: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com>
Link: https://lore.kernel.org/8d8534a704c4f162f347a84830710db32a927b2e.1744432270.git.ritesh.list@gmail.com
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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>
Add a IOMAP_F_ANON_WRITE flag that indicates that the write I/O does not
have a target block assigned to it yet at iomap time and the file system
will do that in the bio submission handler, splitting the I/O as needed.
This is used to implement Zone Append based I/O for zoned XFS, where
splitting writes to the hardware limits and assigning a zone to them
happens just before sending the I/O off to the block layer, but could
also be useful for other things like compressed I/O.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20250206064035.2323428-4-hch@lst.de
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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Merge tag 'vfs-6.12.blocksize' of gitolite.kernel.org:pub/scm/linux/kernel/git/vfs/vfs
Pull vfs blocksize updates from Christian Brauner:
"This contains the vfs infrastructure as well as the xfs bits to enable
support for block sizes (bs) larger than page sizes (ps) plus a few
fixes to related infrastructure.
There has been efforts over the last 16 years to enable enable Large
Block Sizes (LBS), that is block sizes in filesystems where bs > page
size. Through these efforts we have learned that one of the main
blockers to supporting bs > ps in filesystems has been a way to
allocate pages that are at least the filesystem block size on the page
cache where bs > ps.
Thanks to various previous efforts it is possible to support bs > ps
in XFS with only a few changes in XFS itself. Most changes are to the
page cache to support minimum order folio support for the target block
size on the filesystem.
A motivation for Large Block Sizes today is to support high-capacity
(large amount of Terabytes) QLC SSDs where the internal Indirection
Unit (IU) are typically greater than 4k to help reduce DRAM and so in
turn cost and space. In practice this then allows different
architectures to use a base page size of 4k while still enabling
support for block sizes aligned to the larger IUs by relying on high
order folios on the page cache when needed.
It also allows to take advantage of the drive's support for atomics
larger than 4k with buffered IO support in Linux. As described this
year at LSFMM, supporting large atomics greater than 4k enables
databases to remove the need to rely on their own journaling, so they
can disable double buffered writes, which is a feature different cloud
providers are already enabling through custom storage solutions"
* tag 'vfs-6.12.blocksize' of gitolite.kernel.org:pub/scm/linux/kernel/git/vfs/vfs: (22 commits)
Documentation: iomap: fix a typo
iomap: remove the iomap_file_buffered_write_punch_delalloc return value
iomap: pass the iomap to the punch callback
iomap: pass flags to iomap_file_buffered_write_punch_delalloc
iomap: improve shared block detection in iomap_unshare_iter
iomap: handle a post-direct I/O invalidate race in iomap_write_delalloc_release
docs:filesystems: fix spelling and grammar mistakes in iomap design page
filemap: fix htmldoc warning for mapping_align_index()
iomap: make zero range flush conditional on unwritten mappings
iomap: fix handling of dirty folios over unwritten extents
iomap: add a private argument for iomap_file_buffered_write
iomap: remove set_memor_ro() on zero page
xfs: enable block size larger than page size support
xfs: make the calculation generic in xfs_sb_validate_fsb_count()
xfs: expose block size in stat
xfs: use kvmalloc for xattr buffers
iomap: fix iomap_dio_zero() for fs bs > system page size
filemap: cap PTE range to be created to allowed zero fill in folio_map_range()
mm: split a folio in minimum folio order chunks
readahead: allocate folios with mapping_min_order in readahead
...
Fixed 3 typos in design.rst
Signed-off-by: Xiaxi Shen <shenxiaxi26@gmail.com>
Link: https://lore.kernel.org/r/20240807070536.14536-1-shenxiaxi26@gmail.com
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Capture the design of iomap and how to port filesystems to use it.
Apologies for all the rst formatting, but it's necessary to distinguish
code from regular text.
A lot of this has been collected from various email conversations, code
comments, commit messages, my own understanding of iomap, and
Ritesh/Luis' previous efforts to create a document. Please note a large
part of this has been taken from Dave's reply to last iomap doc
patchset. Thanks to Ritesh, Luis, Dave, Darrick, Matthew, Christoph and
other iomap developers who have taken time to explain the iomap design
in various emails, commits, comments etc.
Cc: Dave Chinner <david@fromorbit.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Inspired-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Link: https://lore.kernel.org/r/20240614214347.GK6125@frogsfrogsfrogs
Signed-off-by: Christian Brauner <brauner@kernel.org>
