From: Darrick J. Wong <djwong@xxxxxxxxxx>
Zorro reported that the cleanup function in common/xfs_metadump_tests
zapped one of his test machines because of a well known shell variable
expansion + globbing footgun. This can trigger when running fstests on
older configurations where a test adds _cleanup_verify_metadump to the
local _cleanup function but exits before calling _setup_verify_metadump
to set XFS_METADUMP_IMG to a non-empty value.
Redesign the cleanup function to check for non-empty values of
XFS_METADUMP_{FILE,IMG} before proceeding with the rm. Change the
globbed parameter of "rm -f $XFS_METADUMP_IMG*" to a for loop so that if
the glob does not match any files, the loop variable will be set to a
path that does not resolve anywhere.
Longer term maybe we ought to set -u or something. Or figure out how to
make the root filesystem readonly when we're running a test.
Reported-by: Zorro Lang <zlang@xxxxxxxxxx>
Link: https://lore.kernel.org/fstests/20240205060016.7fgiyafbnrvf5chj@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/
Fixes: 85c1e0f518 ("common: refactor metadump v1 and v2 tests")
Signed-off-by: Darrick J. Wong <djwong@xxxxxxxxxx>
---
common/xfs_metadump_tests | 19 +++++++++++++++----
1 file changed, 15 insertions(+), 4 deletions(-)
diff --git a/common/xfs_metadump_tests b/common/xfs_metadump_tests
index 5a5579b6b9..c8652f16ea 100644
--- a/common/xfs_metadump_tests
+++ b/common/xfs_metadump_tests
@@ -15,12 +15,23 @@ _setup_verify_metadump()
_cleanup_verify_metadump()
{
+ local img
+
_scratch_unmount &>> $seqres.full
- losetup -n -a -O BACK-FILE,NAME | grep "^$XFS_METADUMP_IMG" | while read backing ldev; do
- losetup -d "$ldev"
- done
- rm -f "$XFS_METADUMP_FILE" "$XFS_METADUMP_IMG"*
+ test -n "$XFS_METADUMP_FILE" && rm -f "$XFS_METADUMP_FILE"
+
+ if [ -n "$XFS_METADUMP_IMG" ]; then
+ losetup -n -a -O BACK-FILE,NAME | grep "^$XFS_METADUMP_IMG" | while read backing ldev; do
+ losetup -d "$ldev"
+ done
+
+ # Don't call rm directly with a globbed argument here to avoid
+ # issues issues with variable expansions.
+ for img in "$XFS_METADUMP_IMG"*; do
+ test -e "$img" && rm -f "$img"
+ done
+ fi
}
# Can xfs_metadump snapshot the fs metadata to a v1 metadump file?
