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e3e8e176ca
Mike noted that when NFSD responds to an NFS_FILE_SYNC WRITE, it
does not also persist file time stamps. To wit, Section 18.32.3
of RFC 8881 mandates:
> The client specifies with the stable parameter the method of how
> the data is to be processed by the server. If stable is
> FILE_SYNC4, the server MUST commit the data written plus all file
> system metadata to stable storage before returning results. This
> corresponds to the NFSv2 protocol semantics. Any other behavior
> constitutes a protocol violation. If stable is DATA_SYNC4, then
> the server MUST commit all of the data to stable storage and
> enough of the metadata to retrieve the data before returning.
Commit 3f3503adb332 ("NFSD: Use vfs_iocb_iter_write()") replaced:
- flags |= RWF_SYNC;
with:
+ kiocb.ki_flags |= IOCB_DSYNC;
which appears to be correct given:
if (flags & RWF_SYNC)
kiocb_flags |= IOCB_DSYNC;
in kiocb_set_rw_flags(). However the author of that commit did not
appreciate that the previous line in kiocb_set_rw_flags() results
in IOCB_SYNC also being set:
kiocb_flags |= (__force int) (flags & RWF_SUPPORTED);
RWF_SUPPORTED contains RWF_SYNC, and RWF_SYNC is the same bit as
IOCB_SYNC. Reviewers at the time did not catch the omission.
Reported-by: Mike Snitzer <snitzer@kernel.org>
Closes: https://lore.kernel.org/linux-nfs/20251018005431.3403-1-cel@kernel.org/T/#t
Fixes: 3f3503adb332 ("NFSD: Use vfs_iocb_iter_write()")
Cc: stable@vger.kernel.org
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: NeilBrown <neil@brown.name>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.