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Re: CVS commit: src/sys/kern
David Laight <david%l8s.co.uk@localhost> wrote:
> On Sun, Jan 22, 2012 at 03:48:51AM +0000, Mindaugas Rasiukevicius wrote:
> > Module Name: src
> > Committed By: rmind
> > Date: Sun Jan 22 03:48:51 UTC 2012
> > Modified Files:
> > src/sys/kern: kern_fileassoc.c
> > Log Message:
> > fileassoc_file_delete: pre-check whether fileassoc was used and thus
> > avoid acquiring kernel-lock, which damages sys_unlink() performance.
> Erm... looking at the file the locking in there looks decidedly dubious.
> 1) There doesn't seem to be any locking on the hash table.
> 2) It isn't clear why the KERNEL_LOCK was acquired in one specific path.
> 3) If fileassoc_file_delete() is expected to remove all references for
> a vnode, something external must have forced the state of the vnode.
> (otherwise the stuff might be added - inc. global init - while this
> code is being called.
Yes, locking issues are known in this code (see e.g. PR/35351) and I would
say fileassoc(9) should be disabled by default while this is resolved.
However, I do not really have much interest in fixing fileassoc(9), so my
only concern was to fix performance degradation of unlink(2) due to it.
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