[PATCH] fstests: btrfs/021: redirect the output of defrag command

[Qu Wenruo <wqu@suse.com>]

[BUG]
Test case btrfs/021 will fail with v6.0 btrfs-progs, with the extra
output:

     QA output created by 021
    +/mnt/scratch/padding-0
    +/mnt/scratch/padding-1
    +/mnt/scratch/padding-2
    +/mnt/scratch/padding-3
    +/mnt/scratch/padding-4
    +/mnt/scratch/padding-5
    ...

[CAUSE]
In fact this is a btrfs-progs bug, btrfs-progs commit db2f85c8751c
("btrfs-progs: fi defrag: add global verbose option") changed the output
level of defrag command.

[FIX]
This will be fixed in btrfs-progs, while as a workaround we can redirect
the stdout into $seqres.full.

If we hit some error, the stderr will still pollute the golden output
and be caught by the test case.

Signed-off-by: Qu Wenruo <wqu@suse.com>
---
 tests/btrfs/021 | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/btrfs/021 b/tests/btrfs/021
index 5943da2f..6b6383cb 100755
--- a/tests/btrfs/021
+++ b/tests/btrfs/021
@@ -23,7 +23,7 @@ run_test()
 	sleep 0.5
 
 	find $SCRATCH_MNT -type f -print0 | xargs -0 \
-	$BTRFS_UTIL_PROG filesystem defrag -f
+	$BTRFS_UTIL_PROG filesystem defrag -f >> $seqres.full
 
 	sync
 	wait
-- 
2.38.0