afs: avoid extra VL_GetEntryByName for .readonly's
In the VLDB, there's only one logical entry for a volume and its
associated clones; there are not separate entries for the RW volume
"avol", the RO volume "avol.readonly", and the BK volume
"avol.backup". And so, when looking up a volume in the VLDB by name,
the vlserver ignores any trailing ".readonly" or ".backup" in the
given name. More concretely, the result of calling
VL_GetEntryByName*("avol") is identical to that from calling
VL_GetEntryByName*("avol.readonly").
Accordingly, if afs_GetVolumeByName(name) failed because the volume
was not found in the VLDB, afs_GetVolumeByName(name.readonly) will
fail as well (barring a change in external circumstances, such as the
volume being created or a network connection coming back up).
Therefore, the extra call in EvalMountData() is not necessary and can
be removed.
Remove the extra call, to slightly improve the response time of the
client if the volume in question does not exist, and to reduce
vlserver load when patched clients are looking up nonexistent volumes.
Change-Id: I4f2f668107281565ae72a563a263121bd9bb7e3c
Reviewed-on: https://gerrit.openafs.org/13334
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Marcio Brito Barbosa <mbarbosa@sinenomine.net>
Reviewed-by: Cheyenne Wills <cwills@sinenomine.net>
Reviewed-by: Benjamin Kaduk <kaduk@mit.edu>