[5/9] check: document mkfs.xfs reliance on fstests exports

Commit Message

Darrick J. Wong June 28, 2022, 8:21 p.m. UTC

From: Darrick J. Wong <[e-mail]>

There are a number of fstests that employ special (and now unsupported)
XFS filesystem configurations to perform testing in a controlled
environment.  The presence of the QA_CHECK_FS and MSGVERB variables are
used by mkfs.xfs to detect that it's running inside fstests, which
enables the unsupported configurations.  Nobody else should be using
filesystems with tiny logs, non-redundant superblocks, or smaller than
the (new) minimum supported size.

Signed-off-by: Darrick J. Wong <[e-mail]>
---
 check |    3 +++
 1 file changed, 3 insertions(+)

Comments

Dave Chinner June 29, 2022, 4:22 a.m. UTC | #1

On Tue, Jun 28, 2022 at 01:21:45PM -0700, Darrick J. Wong wrote:
> From: Darrick J. Wong <[e-mail]>
> 
> There are a number of fstests that employ special (and now unsupported)
> XFS filesystem configurations to perform testing in a controlled
> environment.  The presence of the QA_CHECK_FS and MSGVERB variables are
> used by mkfs.xfs to detect that it's running inside fstests, which
> enables the unsupported configurations.  Nobody else should be using
> filesystems with tiny logs, non-redundant superblocks, or smaller than
> the (new) minimum supported size.
> 
> Signed-off-by: Darrick J. Wong <[e-mail]>

looks fine, and answers a question I had looking at some of the
mkfs modifications you've proposed.

Reviewed-by: Dave Chinner <[e-mail]>

Patch

diff --git a/check b/check
index 2ea2920f..4b0ebad6 100755
--- a/check
+++ b/check
@@ -33,6 +33,9 @@  _err_msg=""
 # start the initialisation work now
 iam=check
 
+# mkfs.xfs uses the presence of both of these variables to enable formerly
+# supported tiny filesystem configurations that fstests use for fuzz testing
+# in a controlled environment
 export MSGVERB="text:action"
 export QA_CHECK_FS=${QA_CHECK_FS:=true}