[saturnero@freesbie.org: Weird behaviour of mount_unionfs with
executables]
Scott Long
scottl at samsco.org
Mon Jul 4 00:21:27 GMT 2005
Stephan Uphoff wrote:
> On Sun, 2005-07-03 at 20:02, Scott Long wrote:
>
>>Stephan Uphoff wrote:
>>
>>>I suspect the changes in revision 1.272 of kern_exec.c trigger the
>>>copy operation.
>>>
>>>Looks like you need a noatime option for union_fs.
>>>
>>>Stephan
>>
>>Does this mean that every vnode that gets executed gets dirtied and all
>>its pages resynced to the backing store, or just the inode block?
>
>
> The kernel calls VOP_SETATTR to set the access time of the file.
> union_fs detects that it does not have an upper layer copy of the file
> to modify the attributes on and decides to copy it.
> The vm layer does not (directly) come into play on this.
>
> Stephan
>
Ok, so this is just a limitation of unionfs, not the vnode pager. You
had me scared that we'd be doing a whole lot of needless disk i/o.
Scott
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