On Thu, Mar 14, 2019 at 02:29:06PM -0700, Darrick J. Wong wrote: > From: Darrick J. Wong <darrick.wong@xxxxxxxxxx> > > When writing to a delalloc region in the data fork, commit the new > allocations (of the da reservation) as unwritten so that the mappings > are only marked written once writeback completes successfully. This > fixes the problem of stale data exposure if the system goes down during > targeted writeback of a specific region of a file, as tested by > generic/042. So what does this do to buffered sequential and random write performance? Next, if the entire delalloc extent being allocated is beyond the on-disk EOF (typical for extending sequential buffered writes), why do we want those to be allocated as unwritten? i.e. isn't "allocate as unwritten" only necessary for delalloc extent allocation inside EOF? Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx
