You will find other problems.
The other bit to this is the patch to resolve the deadlock issue I spoke
about just above. This is likely where most of the current problems
started and the fact that we have always had to drop the mutex to call
back the daemon.
I can post the patches as well if that helps.
The description accompanying that patch was (the inconsistent locking
referred to here is what was described above):
"Due to inconsistent locking in the VFS between calls to lookup and
revalidate deadlock can occur in the automounter.
The inconsistency is that the directory inode mutex is held for both
lookup and revalidate calls when called via lookup_hash whereas it is
held only for lookup during a path walk. Consequently, if the mutex
is held during a call to revalidate autofs4 can't release the mutex
to callback the daemon as it can't know whether it owns the mutex.
This situation happens when a process tries to create a directory
within an automount and a second process also tries to create the
same directory between the lookup and the mkdir. Since the first
process has dropped the mutex for the daemon callback, the second
process takes it during revalidate leading to deadlock between the
autofs daemon and the second process when the daemon tries to create
the mount point directory.
After spending quite a bit of time trying to resolve this on more than
one occassion, using rather complex and ulgy approaches, it turns out
that just delaying the hashing of the dentry until the create operation
work fine."
Ian
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