VOL_LOCK needed when traversing DiskPartitionList
VLockPartition sets VOL_LOCK, opens (perhaps creating) the lock file
for a partition, and flock's it. VUnlockPartition, sets VOL_LOCK, and
closes the lock file fd.
VLockPartition is called from the salvager. Nothing ever calls
VUnlockPartition.
VPFullUnlock is called every 30 seconds, does NOT set VOL_LOCK, and
happily closes any lock file fd it finds, breaking any lock set with
flock.
Other routines use the VOL_LOCK when traversing DiskPartitionList.
Change-Id: I683547f574b1f760e72014f5d44ce3987f07b5df
Reviewed-on: http://gerrit.openafs.org/1213
Reviewed-by: Dan Hyde <drh@umich.edu>
Tested-by: Dan Hyde <drh@umich.edu>
Reviewed-by: Derrick Brashear <shadow@dementia.org>
Tested-by: Derrick Brashear <shadow@dementia.org>