On Tue, Jul 07, 2020 at 03:16:29PM -0400, Waiman Long wrote: > One way to avoid this splat is to add GFP_NOFS to the affected allocation > calls by using the memalloc_nofs_save()/memalloc_nofs_restore() pair. > This shouldn't matter unless the system is really running out of memory. > In that particular case, the filesystem freeze operation may fail while > it was succeeding previously. > > Without this patch, the command sequence below will show that the lock > dependency chain sb_internal -> fs_reclaim exists. > > # fsfreeze -f /home > # fsfreeze --unfreeze /home > # grep -i fs_reclaim -C 3 /proc/lockdep_chains | grep -C 5 sb_internal > > After applying the patch, such sb_internal -> fs_reclaim lock dependency > chain can no longer be found. Because of that, the locking dependency > warning will not be shown. > > Suggested-by: Dave Chinner <david@xxxxxxxxxxxxx> > Signed-off-by: Waiman Long <longman@xxxxxxxxxx> Looks good. Thanks for working through this, Waiman. Reviewed-by: Dave Chinner <dchinner@xxxxxxxxxx> Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx
