On Thu, Dec 13, 2012 at 06:10:49PM -0800, Darrick J. Wong wrote: > On Thu, Dec 13, 2012 at 05:48:06PM -0800, Andy Lutomirski wrote: > > On 12/13/2012 12:08 AM, Darrick J. Wong wrote: > > > Several complaints have been received regarding long file write latencies when > > > memory pages must be held stable during writeback. Since it might not be > > > acceptable to stall programs for the entire duration of a page write (which may > > > take many milliseconds even on good hardware), enable a second strategy wherein > > > pages are snapshotted as part of submit_bio; the snapshot can be held stable > > > while writes continue. > > > > > > This provides a band-aid to provide stable page writes on jbd without needing > > > to backport the fixed locking scheme in jbd2. A mount option is added to ext4 > > > to allow administrators to enable it there. > > > > I'm a bit confused as to what it has to do with ext3. Wouldn't this be > > useful as a mount option everywhere, though? > > ext3 requires snapshots; the rest are ok with either strategy. > > *If* snapshotting is generally liked, then yes I'll go redo it as a vfs mount > option. It's copying every single IO, right? If so, then please don't propagate any further than is necessary to fix the broken filesystems... Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
