[PATCH 1/2] xfs/270: only check new_ro_compat value when mkfs.xfs supports nrext64 feature

[Yang Xu <xuyang2018.jy@fujitsu.com>]

Currently, this case fails on old xfsprogs as below:
+/var/lib/xfstests/tests/xfs/270: line 51: [: !=: unary operator expected

Getting ro_compat value will report the following error after setting new ro_compat
value:
+cache_purge: shake on cache 0x56033fde4920 left 1 nodes!?
+cache_purge: shake on cache 0x56033fde4920 left 1 nodes!?
+cache_zero_check: refcount is 1, not zero (node=0x56033fdf9110

Old xfsprogs miss a bugfix
f4afdcb0ad ("xfs_db: clean up the salvage read callsites in set_cur()").

Here we skip the get step of new ro_comap value when nrext64 feature is supported.
Also will add a new test to cover this xfsprog bug.

Signed-off-by: Yang Xu <xuyang2018.jy@fujitsu.com>
---
 tests/xfs/270 | 23 ++++++++++++++++-------
 1 file changed, 16 insertions(+), 7 deletions(-)

diff --git a/tests/xfs/270 b/tests/xfs/270
index b740c379..5ff83ead 100755
--- a/tests/xfs/270
+++ b/tests/xfs/270
@@ -22,6 +22,10 @@ _require_scratch_nocheck
 # Only V5 XFS disallow rw mount/remount with unknown ro-compat features
 _require_scratch_xfs_crc
 
+nrext64_supported=0
+_scratch_mkfs_xfs_supported -m crc=1 -i nrext64 > /dev/null 2>&1 && \
+	nrext64_supported=1
+
 _scratch_mkfs_xfs >>$seqres.full 2>&1
 
 # set the highest bit of features_ro_compat, use it as an unknown
@@ -43,13 +47,18 @@ ro_compat=$(echo $ro_compat | \
 _scratch_xfs_set_metadata_field "features_ro_compat" "$ro_compat" "sb 0" \
 				> $seqres.full 2>&1
 
-# read the newly set ro compat filed for verification
-new_ro_compat=$(_scratch_xfs_get_metadata_field "features_ro_compat" "sb 0" \
-						2>/dev/null)
-
-# verify the new ro_compat field is correct.
-if [ $new_ro_compat != $ro_compat ]; then
-	echo "Unable to set new features_ro_compat. Wanted $ro_compat, got $new_ro_compat"
+# Indeed, xfsprogs has a bug here and fixed by commit f4afdcb
+# ("xfs_db: clean up the salvage read callsites in set_cur()")
+# Here, we use nrext64 feature as a proxy.
+if [ $nrext64_supported -eq 1 ]; then
+	# read the newly set ro compat filed for verification
+	new_ro_compat=$(_scratch_xfs_get_metadata_field "features_ro_compat" \
+					"sb 0" 2>/dev/null)
+	# verify the new ro_compat field is correct.
+	if [ $new_ro_compat != $ro_compat ]; then
+		echo "Unable to set new features_ro_compat. Wanted $ro_compat, \
+			got $new_ro_compat"
+	fi
 fi
 
 # rw mount with unknown ro-compat feature should fail
-- 
2.27.0