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In the case where we have received a successful reply to an RPC request, but while processing the reply the client in rpc_decode_header() finds an expired context, the code ends up propagating the error to the caller instead of getting a new context and retrying the request. To give more details, in rpc_decode_header() we call rpcauth_checkverf() will call into the gss and internally will at some point call gss_validate() which has a check if the current’s context lifetime expired, and it would fail. The reason for the failure gets ‘scrubbed’ and translated to EACCES so when we get back to rpc_decode_header() we just go to “out_verifier” which for that error would get converted to “out_garbage” (ie it’s treated as garballed reply) and the next action is call_encode. Which (1) doesn’t reencode or re-send (not to mention no upcall happens because context expires as that reason just not known) and it again fails in the same decoding process. After re-trying it 3 times the error is propagated back to the caller (ie nfs4_write_done_cb() in the case a failing write). To fix this, instead we need to look to the case where the server decides that context has expired and replies with an RPC auth error. In that case, the rpc_decode_header() goes to "out_msg_denied" in that we return EKEYREJECTED which in call_decode() is sent to “call_reserve” which triggers an upcalls and a re-try of the operation. The proposed fix is in case of a failed rpc_decode_header() to check if credentials were set to be invalid and use that as a proxy for deciding that context has expired and then treat is same way as receiving an auth error. Signed-off-by: Olga Kornievskaia <kolga@netapp.com> Reviewed-by: Benjamin Coddington <bcodding@redhat.com> Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.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.