b79e3569ba
[ Upstream commit bf51c52a1f3c238d72c64e14d5e7702d3a245b82 ] nfsd_cache_csum() currently assumes that the server's RPC layer has been advancing rq_arg.head[0].iov_base as it decodes an incoming request, because that's the way it used to work. On entry, it expects that buf->head[0].iov_base points to the start of the NFS header, and excludes the already-decoded RPC header. These days however, head[0].iov_base now points to the start of the RPC header during all processing. It no longer points at the NFS Call header when execution arrives at nfsd_cache_csum(). In a retransmitted RPC the XID and the NFS header are supposed to be the same as the original message, but the contents of the retransmitted RPC header can be different. For example, for krb5, the GSS sequence number will be different between the two. Thus if the RPC header is always included in the DRC checksum computation, the checksum of the retransmitted message might not match the checksum of the original message, even though the NFS part of these messages is identical. The result is that, even if a matching XID is found in the DRC, the checksum mismatch causes the server to execute the retransmitted RPC transaction again. Reviewed-by: Jeff Layton <jlayton@kernel.org> Tested-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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 Restructured Text 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.