On Fri, Nov 10, 2006 at 12:11:46AM +0100, Pavel Machek wrote: > ? Not sure if I quite understand, but if dm breaks sync... something > is teribly wrong with dm. And we do simple sys_sync()... so I do not > think we have a problem. If you want to handle arbitrary kernel state, you might have a device-mapper device somewhere lower down the stack of devices that is queueing any I/O that reaches it. So anything waiting for I/O completion will wait until the dm process that suspended that device has finished whatever it is doing - and that might be a quick thing carried out by a userspace lvm tool, or a long thing carried out by an administrator using dmsetup. I'm guessing you need a way of detecting such state lower down the stack then optionally either aborting the operation telling the user it can't be done at present; waiting for however long it takes (perhaps for ever if the admin disappeared); or more probably skipping those devices on a 'best endeavours' basis. I'm suggesting sysfs or something built on bd_claim might offer a mechanism for traversing the stack. Alasdair -- agk@xxxxxxxxxx -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
