On Thu, May 21, 2020 at 07:53:23PM -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. > > Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx> > Reviewed-by: Christoph Hellwig <hch@xxxxxx> > Reviewed-by: Brian Foster <bfoster@xxxxxxxxxx> Observation: yesterday I forced a 4kB file create workload to use unwritten extents by setting an extent size hint. That caused about 4,500 xfs-conv kworker threads to be spawned by the workload which had 16 userspace processes creating files... I expect that any sort of "create lots of small files" worklaod is going to cause xfs-conv kworker explosions, so be prepared for users to start reporting kworker explosions with this in place... Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx
