Messages in this thread | | | From | "Rafael J. Wysocki" <> | Subject | Re: [PATCH] Freeze bdevs when freezing processes. | Date | Wed, 25 Oct 2006 14:32:39 +0200 |
| |
On Wednesday, 25 October 2006 10:47, Pavel Machek wrote: > On Wed 2006-10-25 18:38:30, David Chinner wrote: > > On Wed, Oct 25, 2006 at 10:10:01AM +0200, Pavel Machek wrote: > > > > Hence the only way to correctly rebuild the XFS state on resume is > > > > to quiesce the filesystem on suspend and thaw it on resume so as to > > > > trigger log recovery. > > > > > > No, during suspend/resume, memory image is saved, and no state is > > > lost. We would not even have to do sys_sync(), and suspend/resume > > > would still work properly. > > > > It seems to me that you ensure the filesystem is synced to disk and > > then at some point later you record the memory state of the > > filesystem, but these happen at different times. That leaves a > > window for things to get out of sync again, right? > > I DO NOT HAVE TO ENSURE FILESYSTEM IS SYNCED. That sys_sync() is > optional. > > Recording of memory state is atomic, and as long as noone writes to > the disk after atomic snapshot, memory image matches what is on disk.
Well, my impression is that this is exactly what happens here: Something in the XFS code causes metadata to be written to disk _after_ the atomic snapshot.
That's why I asked if the dirty XFS metadata were flushed by a kernel thread.
Greetings, Rafael
-- You never change things by fighting the existing reality. R. Buckminster Fuller - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |