At the moment, at the end of a DIO write, cifs calls netfs_resize_file() to adjust the size of the file if it needs it. This will reduce the zero_point (the point above which we assume a read will just return zeros) if it's more than the new i_size, but won't increase it. With DIO writes, however, we definitely want to increase it as we have clobbered the local pagecache and then written some data that's not available locally. Fix cifs to make the zero_point above the end of a DIO or unbuffered write. This fixes corruption seen occasionally with the generic/708 xfs-test. In that case, the read-back of some of the written data is being short-circuited and replaced with zeroes. Fixes: 3ee1a1fc3981 ("cifs: Cut over to using netfslib") Cc: stable@vger.kernel.org Reported-by: Steve French <sfrench@samba.org> Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Paulo Alcantara (Red Hat) <pc@manguebit.com> cc: Jeff Layton <jlayton@kernel.org> cc: linux-cifs@vger.kernel.org cc: netfs@lists.linux.dev cc: linux-fsdevel@vger.kernel.org Signed-off-by: Steve French <stfrench@microsoft.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.
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