On Fri 2006-11-17 12:40:51, David Chinner wrote: > On Fri, Nov 17, 2006 at 12:40:53AM +0100, Pavel Machek wrote: > > On Fri 2006-11-17 10:23:49, David Chinner wrote: > > > On Sun, Nov 12, 2006 at 11:43:05PM +0100, Rafael J. Wysocki wrote: > > > > On Sunday, 12 November 2006 23:30, David Chinner wrote: > > > > > And how does freezing them at that point in time guarantee consistent > > > > > filesystem state? > > > > > > > > If the work queues are frozen, there won't be any fs-related activity _after_ > > > > we create the suspend image. > > > > > > fs-related activity before or after the suspend image is captured is > > > not a problem - it's fs-related activity _during_ the suspend that > > > is an issue here. If we have async I/O completing during the suspend > > > image capture, we've got problems.... > > > > fs-related activity _after_ image is captured definitely is a problem > > -- it breaks swsusp invariants. > > > > During image capture, any fs-related activity is not possible, as we > > are running interrupts disabled, DMA disabled. > > Ok, so the I/o that finishes during the image capture won't be reported > until after the capture completes. that means we lose the capability There's no I/O in flight during image capture. Interrupts are disabled, DMAs are stopped, and drivers were told to shut down (that includes finishing any outstanding work, and drivers do that currently; but perhaps docs should be more explicit about it). Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
