[LTP] [PATCH] lib/tst_mkfs: detect btrfs -f option correctly

[Eryu Guan]

btrfs-progs commit 3f312d500b73 ("btrfs-progs: mkfs, align help
strings") changed the usage text:

 - -f --force
 + -f|--force

and tst_mkfs failed to add -f option to mkfs.btrfs.

Update the grep regex to match both old and new text, and now -f option
is added to mkfs.btrfs.

[root@host ltp]# LTP_DEV_FS_TYPE=btrfs ./chown04
chown04     0  TINFO  :  Found free device '/dev/loop0'
chown04     0  TINFO  :  Appending '-f' flag to mkfs.btrfs
chown04     0  TINFO  :  Formatting /dev/loop0 with btrfs extra opts=''
...

Also use -q option of grep instead of redirecting output to /dev/null to
avoid line over 80 column.

Signed-off-by: Eryu Guan <eguan@redhat.com>
---
 lib/tst_mkfs.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/tst_mkfs.c b/lib/tst_mkfs.c
index c01cdf3..5f959a4 100644
--- a/lib/tst_mkfs.c
+++ b/lib/tst_mkfs.c
@@ -45,7 +45,7 @@ void tst_mkfs(void (cleanup_fn)(void), const char *dev,
 		/*
 		 * The -f option was added to btrfs-progs v3.12
 		 */
-		if (!tst_system("mkfs.btrfs 2>&1 | grep '\\-f ' >/dev/null")) {
+		if (!tst_system("mkfs.btrfs 2>&1 | grep -q '\\-f[ |]'")) {
 			tst_resm(TINFO, "Appending '-f' flag to mkfs.%s",
 				fs_type);
 			argv[pos++] = "-f";
-- 
2.4.3