Re: [PATCH v2 1/3] common: filter aiodio dmesg after fs/iomap.c to fs/iomap/ move

["Darrick J. Wong" <darrick.wong@oracle.com>]

On Sun, Jul 28, 2019 at 07:30:36PM +0800, Eryu Guan wrote:
> On Thu, Jul 25, 2019 at 11:03:30AM -0700, Darrick J. Wong wrote:
> > From: Darrick J. Wong <darrick.wong@oracle.com>
> > 
> > Since the iomap code are moving to fs/iomap/ we have to add new entries
> > to the aiodio dmesg filter to reflect this.
> > 
> > Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
> > ---
> > v2: fix all the iomap regexes
> > ---
> >  common/filter |    9 +++++----
> >  1 file changed, 5 insertions(+), 4 deletions(-)
> > 
> > diff --git a/common/filter b/common/filter
> > index ed082d24..2e32ab10 100644
> > --- a/common/filter
> > +++ b/common/filter
> > @@ -550,10 +550,10 @@ _filter_aiodio_dmesg()
> >  	local warn2="WARNING:.*fs/xfs/xfs_file\.c:.*xfs_file_dio_aio_read.*"
> >  	local warn3="WARNING:.*fs/xfs/xfs_file\.c:.*xfs_file_read_iter.*"
> >  	local warn4="WARNING:.*fs/xfs/xfs_file\.c:.*xfs_file_aio_read.*"
> > -	local warn5="WARNING:.*fs/iomap\.c:.*iomap_dio_rw.*"
> > +	local warn5="WARNING:.*fs/iomap.*:.*iomap_dio_rw.*"
> >  	local warn6="WARNING:.*fs/xfs/xfs_aops\.c:.*__xfs_get_blocks.*"
> > -	local warn7="WARNING:.*fs/iomap\.c:.*iomap_dio_actor.*"
> > -	local warn8="WARNING:.*fs/iomap\.c:.*iomap_dio_complete.*"
> > +	local warn7="WARNING:.*fs/iomap.*:.*iomap_dio_actor.*"
> > +	local warn8="WARNING:.*fs/iomap.*:.*iomap_dio_complete.*"
> 
> I don't think we need new filters anymore, as commit 5a9d929d6e13
> ("iomap: report collisions between directio and buffered writes to
> userspace") replaced the WARN_ON with a pr_crit(). These filters are
> there only for old kernels.

Aaaaahh... but I /did/ write this patch because I kept hitting a WARNING
somewhere in the iomap directio code, and you know what?  It's one of the
warnings about a bogus iomap type in iomap_dio_actor.

I /think/ this is what happens when a buffered write sneaks in and
creates a delalloc reservation after the directio write has zapped the
page cache but before it actually starts iterating extents.
Consequently iomap_dio_actor sees the delalloc extent and WARNs.

Will have to recheck this, but maybe the kernel needs to deploy that
helper that 5a9d929d6e13 for that case.

--D

> Thanks,
> Eryu
> 
> >  	local warn9="WARNING:.*fs/direct-io\.c:.*dio_complete.*"
> >  	sed -e "s#$warn1#Intentional warnings in xfs_file_dio_aio_write#" \
> >  	    -e "s#$warn2#Intentional warnings in xfs_file_dio_aio_read#" \
> > @@ -563,7 +563,8 @@ _filter_aiodio_dmesg()
> >  	    -e "s#$warn6#Intentional warnings in __xfs_get_blocks#" \
> >  	    -e "s#$warn7#Intentional warnings in iomap_dio_actor#" \
> >  	    -e "s#$warn8#Intentional warnings in iomap_dio_complete#" \
> > -	    -e "s#$warn9#Intentional warnings in dio_complete#"
> > +	    -e "s#$warn9#Intentional warnings in dio_complete#" \
> > +	    -e "s#$warn10#Intentional warnings in iomap_dio_actor#"
> >  }
> >  
> >  # We generate assert related WARNINGs on purpose and make sure test doesn't fail