Re: [PATCH 1/5] populate: export the metadump description name

From: Zorro Lang <zlang@redhat.com>
To: "Darrick J. Wong" <djwong@kernel.org>
Cc: linux-xfs@vger.kernel.org, fstests@vger.kernel.org
Subject: Re: [PATCH 1/5] populate: export the metadump description name
Date: Fri, 14 Oct 2022 00:28:26 +0800	[thread overview]
Message-ID: <20221013162826.hfs75s33giqmfu4t@zlang-mailbox> (raw)
In-Reply-To: <Y0g0u5byHQK/aOEz@magnolia>

On Thu, Oct 13, 2022 at 08:54:35AM -0700, Darrick J. Wong wrote:
> On Thu, Oct 13, 2022 at 10:55:15PM +0800, Zorro Lang wrote:
> > On Tue, Oct 11, 2022 at 06:45:27PM -0700, Darrick J. Wong wrote:
> > > From: Darrick J. Wong <djwong@kernel.org>
> > > 
> > > Not sure why this hasn't been broken all along, but we should be
> > > exporting this variable so that it shows up in subshells....
> > 
> > May I ask where's the subshell which uses $POPULATE_METADUMP?
> 
> _scratch_xfs_fuzz_metadata does this:
> 
> 	echo "${fields}" | while read field; do
> 		echo "${verbs}" | while read fuzzverb; do
> 			__scratch_xfs_fuzz_mdrestore
> 				_xfs_mdrestore "${POPULATE_METADUMP}"
> 
> The (nested) echo piped to while starts subshells.

I'm not so familar with this part, so I didn't a simple test[1], and looks like
the PARAM can be seen, even it's not exported. Do I misunderstand something?

Thanks,
Zorro

[1]
$ echo "$list"
a
b
cc
$ PARAM="This's a test"
$ echo "$list"|while read c1;do echo "$list"|while read c2;do echo $PARAM;done; done
This's a test
This's a test
This's a test
This's a test
This's a test
This's a test
This's a test
This's a test
This's a test

> 
> > > 
> > > Signed-off-by: Darrick J. Wong <djwong@kernel.org>
> > > ---
> > >  common/populate |    6 +++---
> > >  1 file changed, 3 insertions(+), 3 deletions(-)
> > > 
> > > 
> > > diff --git a/common/populate b/common/populate
> > > index cfdaf766f0..b501c2fe45 100644
> > > --- a/common/populate
> > > +++ b/common/populate
> > > @@ -868,9 +868,9 @@ _scratch_populate_cached() {
> > >  	local meta_tag="$(echo "${meta_descr}" | md5sum - | cut -d ' ' -f 1)"
> > >  	local metadump_stem="${TEST_DIR}/__populate.${FSTYP}.${meta_tag}"
> > >  
> > > -	# These variables are shared outside this function
> > > -	POPULATE_METADUMP="${metadump_stem}.metadump"
> > > -	POPULATE_METADUMP_DESCR="${metadump_stem}.txt"
> > > +	# This variable is shared outside this function
> > > +	export POPULATE_METADUMP="${metadump_stem}.metadump"
> > > +	local POPULATE_METADUMP_DESCR="${metadump_stem}.txt"
> > 
> > If the POPULATE_METADUMP_DESCR is not shared outside anymore, how about change
> > it to lower-case?
> 
> Ok.
> 
> --D
> 
> > >  
> > >  	# Don't keep metadata images cached for more 48 hours...
> > >  	rm -rf "$(find "${POPULATE_METADUMP}" -mtime +2 2>/dev/null)"
> > > 
> > 
> 