Messages in this thread |  | | | Date | Wed, 27 May 2009 14:15:42 -0400 (EDT) | | From | Alan Stern <> | | Subject | Re: [PATCH 25/20] sysfs: Only support removing emtpy sysfs directories. |
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On Wed, 27 May 2009, Eric W. Biederman wrote:
> Alan Stern <stern@rowland.harvard.edu> writes: > > > On Wed, 27 May 2009, Kay Sievers wrote: > > > >> On Wed, May 27, 2009 at 01:49, James Bottomley > >> <James.Bottomley@hansenpartnership.com> wrote: > >> > >> > OK ... perhaps we have to wait a little harder: try this; it waits until > >> > all the targets have disappeared from visibility via an event. > >> > >> That seems to work fine here. > > > > It's good for a short-term fix. For the longer term, I still think > > it's a mistake to wait for the sdevs to be released before deleting the > > target. It gives user programs the ability to block the host-removal > > thread indefinitely. > > How can user programs block removal indefinitely today?
As fas as I know, they can't. Instead, they can cause the SCSI layer to unregister a sysfs directory containing a child directory. :-)
Basically, a user program can delay removal of the child (i.e., the target) directory indefinitely, because currently the target isn't unregistered when all its children are removed -- it's unregistered when all its children are _released_.
Alan Stern
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