8759773148
Commit 4281bfec3628 patched the server so that the callback session slot would be free'd for reuse when a callback attempt fails. However, this can often result in the sequence# for the session slot to be advanced such that the client end will reply NFSERR_SEQMISORDERED. To avoid the NFSERR_SEQMISORDERED client reply, this patch negates the sequence# advance for the case where the callback has failed. The common case is a failed back channel, where the callback cannot be sent to the client, and not advancing the sequence# is correct for this case. For the uncommon case where the client's reply to the callback is lost, not advancing the sequence# will indicate to the client that the next callback is a retry and not a new callback. But, since the FreeBSD server always sets "csa_cachethis" false in the callback sequence operation, a retry and a new callback should be handled the same way by the client, so this should not matter. Until you have this patch in your NFSv4.1/4.2 server, you should consider avoiding the use of delegations. Even with this patch, interoperation with the Linux NFSv4.1/4.2 client in kernel versions prior to 5.3 can result in frequent 15second delays if delegations are enabled. This occurs because, for kernels prior to 5.3, the Linux client does a TCP reconnect every time it sees multiple concurrent callbacks and then it takes 15seconds to recover the back channel after doing so. MFC after: 2 weeks
FreeBSD Source:
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Source Roadmap:
| Directory | Description |
|---|---|
| bin | System/user commands. |
| cddl | Various commands and libraries under the Common Development and Distribution License. |
| contrib | Packages contributed by 3rd parties. |
| crypto | Cryptography stuff (see crypto/README). |
| etc | Template files for /etc. |
| gnu | Various commands and libraries under the GNU Public License. Please see gnu/COPYING and gnu/COPYING.LIB for more information. |
| include | System include files. |
| kerberos5 | Kerberos5 (Heimdal) package. |
| lib | System libraries. |
| libexec | System daemons. |
| release | Release building Makefile & associated tools. |
| rescue | Build system for statically linked /rescue utilities. |
| sbin | System commands. |
| secure | Cryptographic libraries and commands. |
| share | Shared resources. |
| stand | Boot loader sources. |
| sys | Kernel sources. |
sys/arch/conf |
Kernel configuration files. GENERIC is the configuration used in release builds. NOTES contains documentation of all possible entries. |
| tests | Regression tests which can be run by Kyua. See tests/README for additional information. |
| tools | Utilities for regression testing and miscellaneous tasks. |
| usr.bin | User commands. |
| usr.sbin | System administration commands. |
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