[PATCH] xfstests: handle new mkfs.btrfs -f option cleanly

[Eric Sandeen <sandeen@redhat.com>]

I added an "-f" option to mkfs.btrfs to force overwrite
of an existing filesystem.  Now on an xfstests run, new
mkfs.btrfs requires it, and old mkfs.btrfs cannot accept
it.

So, add a helper which works out whether -f is needed,
and add it to the MKFS_BTRFS_PROG env. var as necessary,
so that it is an always-included option during the tests.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
---

diff --git a/common.config b/common.config
index 57f505d..9f1d309 100644
--- a/common.config
+++ b/common.config
@@ -101,6 +101,17 @@ set_prog_path()
     return 1
 }
 
+# Handle mkfs.btrfs which does (or does not) require -f to overwrite
+set_btrfs_mkfs_prog_path_with_opts()
+{
+	p=`set_prog_path mkfs.btrfs`
+	if grep -q 'force overwrite' $p; then
+		echo "$p -f"
+	else
+		echo $p
+	fi
+}
+
 _fatal()
 {
     echo "$*"
@@ -185,7 +196,7 @@ case "$HOSTOS" in
     Linux)
         export MKFS_XFS_PROG="`set_prog_path mkfs.xfs`"
         export MKFS_UDF_PROG="`set_prog_path mkudffs`"
-        export MKFS_BTRFS_PROG="`set_prog_path mkfs.btrfs`"
+        export MKFS_BTRFS_PROG="`set_btrfs_mkfs_prog_path_with_opts`"
         export BTRFS_UTIL_PROG="`set_prog_path btrfs`"
         export XFS_FSR_PROG="`set_prog_path xfs_fsr`"
         export MKFS_NFS_PROG="false"