[PATCH 4/6] fstests: btrfs: add helper function to check if btrfs is module

[Anand Jain <anand.jain@oracle.com>]

We need btrfs to be a module so that it can unloaded and reloaded,
so that we can clean up the btrfs internal in memory device list.

This patch adds _require_btrfs_unloadable() and _reload_btrfs_ko()
to help with the same.

Signed-off-by: Anand Jain <anand.jain@oracle.com>
---
 common/rc | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/common/rc b/common/rc
index f2b39ddbee0c..a9391b4cbf57 100644
--- a/common/rc
+++ b/common/rc
@@ -1403,6 +1403,18 @@ _supported_os()
     _notrun "not suitable for this OS: $HOSTOS"
 }
 
+_require_btrfs_unloadable()
+{
+	modprobe -r btrfs || _notrun "btrfs unloadable"
+	modprobe btrfs || _notrun "Can't load btrfs"
+}
+
+_reload_btrfs_ko()
+{
+	modprobe -r btrfs || _fail "btrfs unload failed"
+	modprobe btrfs || _fail "btrfs load failed"
+}
+
 # this test needs a scratch partition - check we're ok & unmount it
 # No post-test check of the device is required. e.g. the test intentionally
 # finishes the test with the filesystem in a corrupt state
-- 
2.7.0