Re: [PATCH 4/6] generic/765: Ignore mkfs warning

Re: [PATCH 4/6] generic/765: Ignore mkfs warning

[Darrick J. Wong]

On Mon, Apr 13, 2026 at 02:34:11PM +0530, Ojaswin Mujoo wrote:
> On Sun, Apr 12, 2026 at 10:38:18PM +0530, Ojaswin Mujoo wrote:
> > On Fri, Apr 10, 2026 at 09:54:35AM -0700, Darrick J. Wong wrote:
> > > On Fri, Apr 10, 2026 at 12:06:04PM +0530, Ojaswin Mujoo wrote:
> > > > This test validates atomic writes for all possible block sizes. In ext4, for
> > > > smaller block sizes with configurations like:
> > > > 
> > > > export MKFS_OPTIONS="-O bigalloc,quota -b 65536 -C 131072"
> > > > 
> > > > The output can get corrupted with warnings like below because clustersize
> > > > more than 16xbs is experimental:
> > > > 
> > > > + 16 times the block size is considered experimental
> > > > 
> > > > Hence pipe these to seqres.full to avoid false negatives.
> > > > 
> > > > Reported-by: Disha Goel <disgoel@linux.ibm.com>
> > > > Signed-off-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
> > > 
> > > Seems fine, though I think I'd rather mke2fs get patched to fix this.
> > > 
> > > I'd let the maintainer decide if he wants this, but ... I'm not sure if
> > > he's actually going to receive this message. :/
> > 
> > Hi Darrick, yes I'm preparing a quick patch for this. We might still
> > need this so people on older distro who wont have the e2fsprogs fix dont
> > see the failure.
> 
> Hi Darrick,
> 
> Looking at it again, I am just wondering if its really an issue that
> mke2fs is printing this warning to stderr. Isn't stderr the right place
> for errors and warning (even non critical ones)?
> 
> Futher, mke2fs has multiple instances where we print warnings to stderr,
> should we go and fix all of them as well?

"stderr" meaning "standard error", I'd say that errors are anything that
prohibits the format from completing, and only errors should go there.

We ought to kick this to the ext4 list though...

--D

> Regards,
> ojaswin
> 
> > 
> > Regards,
> > ojaswin
> > 
> > > 
> > > --D
> > > 
> > > > ---
> > > >  tests/generic/765 | 3 ++-
> > > >  1 file changed, 2 insertions(+), 1 deletion(-)
> > > > 
> > > > diff --git a/tests/generic/765 b/tests/generic/765
> > > > index 09be53db..b7cc70f1 100755
> > > > --- a/tests/generic/765
> > > > +++ b/tests/generic/765
> > > > @@ -64,7 +64,8 @@ test_atomic_writes()
> > > >      local bsize=$1
> > > >  
> > > >      get_mkfs_opts $bsize
> > > > -    _scratch_mkfs $mkfs_opts >> $seqres.full
> > > > +    _scratch_mkfs $mkfs_opts &>> $seqres.full || \
> > > > +        echo "mkfs $mkfs_opts failed"
> > > >      _scratch_mount
> > > >  
> > > >      test "$FSTYP" = "xfs" && _xfs_force_bdev data $SCRATCH_MNT
> > > > -- 
> > > > 2.53.0
> > > > 
> > > > 
> 

Re: [PATCH 4/6] generic/765: Ignore mkfs warning

[Theodore Tso]

> > > > > The output can get corrupted with warnings like below because clustersize
> > > > > more than 16xbs is experimental:
> > > > > 
> > > > > + 16 times the block size is considered experimental
> > > > > 
> > > > > Hence pipe these to seqres.full to avoid false negatives.

You could also suppress the warnings using the -q option, for example:

mke2fs -Fq -t ext4 -O bigalloc,quota -b 4096 -C 131072 /tmp/foo.img 4G

> > Futher, mke2fs has multiple instances where we print warnings to stderr,
> > should we go and fix all of them as well?
> 
> "stderr" meaning "standard error", I'd say that errors are anything that
> prohibits the format from completing, and only errors should go there.

Sure, I'll accept those changes.  But adding -q will allow the test to
pass using older versions of e2fsprogs, while still allowing stderr to
go out the expected output.

					- Ted

Re: [PATCH 4/6] generic/765: Ignore mkfs warning

[Darrick J. Wong]

On Mon, Apr 13, 2026 at 04:42:15PM -0400, Theodore Tso wrote:
> > > > > > The output can get corrupted with warnings like below because clustersize
> > > > > > more than 16xbs is experimental:
> > > > > > 
> > > > > > + 16 times the block size is considered experimental
> > > > > > 
> > > > > > Hence pipe these to seqres.full to avoid false negatives.
> 
> You could also suppress the warnings using the -q option, for example:
> 
> mke2fs -Fq -t ext4 -O bigalloc,quota -b 4096 -C 131072 /tmp/foo.img 4G
> 
> > > Futher, mke2fs has multiple instances where we print warnings to stderr,
> > > should we go and fix all of them as well?
> > 
> > "stderr" meaning "standard error", I'd say that errors are anything that
> > prohibits the format from completing, and only errors should go there.
> 
> Sure, I'll accept those changes.  But adding -q will allow the test to
> pass using older versions of e2fsprogs, while still allowing stderr to
> go out the expected output.

Aha, maybe that's why I've never run into this when QA'ing fstests.

--D

Re: [PATCH 4/6] generic/765: Ignore mkfs warning

[Ojaswin Mujoo]

On Mon, Apr 13, 2026 at 04:42:15PM -0400, Theodore Tso wrote:
> > > > > > The output can get corrupted with warnings like below because clustersize
> > > > > > more than 16xbs is experimental:
> > > > > > 
> > > > > > + 16 times the block size is considered experimental
> > > > > > 
> > > > > > Hence pipe these to seqres.full to avoid false negatives.
> 
> You could also suppress the warnings using the -q option, for example:
> 
> mke2fs -Fq -t ext4 -O bigalloc,quota -b 4096 -C 131072 /tmp/foo.img 4G
> 
> > > Futher, mke2fs has multiple instances where we print warnings to stderr,
> > > should we go and fix all of them as well?
> > 
> > "stderr" meaning "standard error", I'd say that errors are anything that
> > prohibits the format from completing, and only errors should go there.
> 
> Sure, I'll accept those changes.  But adding -q will allow the test to
> pass using older versions of e2fsprogs, while still allowing stderr to
> go out the expected output.

Okay cool, I'll send the patches.

thanks,
ojaswin

> 
> 					- Ted

Re: [PATCH 4/6] generic/765: Ignore mkfs warning

[Zorro Lang]

On Mon, Apr 13, 2026 at 04:42:15PM -0400, Theodore Tso wrote:
> > > > > > The output can get corrupted with warnings like below because clustersize
> > > > > > more than 16xbs is experimental:
> > > > > > 
> > > > > > + 16 times the block size is considered experimental
> > > > > > 
> > > > > > Hence pipe these to seqres.full to avoid false negatives.
> 
> You could also suppress the warnings using the -q option, for example:
> 
> mke2fs -Fq -t ext4 -O bigalloc,quota -b 4096 -C 131072 /tmp/foo.img 4G
> 
> > > Futher, mke2fs has multiple instances where we print warnings to stderr,
> > > should we go and fix all of them as well?
> > 
> > "stderr" meaning "standard error", I'd say that errors are anything that
> > prohibits the format from completing, and only errors should go there.
> 
> Sure, I'll accept those changes.  But adding -q will allow the test to
> pass using older versions of e2fsprogs, while still allowing stderr to
> go out the expected output.

Aha, good point! Thanks Ted :)

> 
> 					- Ted
>