btrfs: make sure we rescan all devices after unregistering

There are some btrfs test cases utilizing
_btrfs_forget_or_module_reload() to unregister all btrfs devices.

However _btrfs_forget_or_module_reload() will unregister all devices,
meaning if TEST_DEV is part of a multi-device btrfs, after those test
cases TEST_DEV will no longer be mountable.

This patch will introduce a new function, btrfs_rescan_devices() to undo
the unregister, so that all later test cases can mount TEST_DEV without
any problem.

Since we are here, also add a missing
_require_btrfs_forget_or_module_loadable for btrfs/225.

Reported-by: Eric Sandeen <sandeen@sandeen.net>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Eryu Guan <guaneryu@gmail.com>

common/btrfs

@@ -411,3 +411,11 @@ _btrfs_forget_or_module_reload()
 
 	_reload_fs_module "btrfs"
 }
+
+# Test cases which utilized _btrfs_forget_or_module_reload() must call this
+# to make sure TEST_DEV can still be mounted. As TEST_DEV can be part of a
+# multi-device btrfs.
+_btrfs_rescan_devices()
+{
+	$BTRFS_UTIL_PROG device scan &> /dev/null
+}

tests/btrfs/124

@@ -35,6 +35,7 @@ _cleanup()
 {
 	cd /
 	rm -f $tmp.*
+	_btrfs_rescan_devices
 }
 
 # get standard environment, filters and checks
@@ -144,6 +145,7 @@ fi
 
 $UMOUNT_PROG $dev2
 _scratch_dev_pool_put
+_btrfs_rescan_devices
 _test_mount
 
 status=0

tests/btrfs/125

@@ -34,6 +34,7 @@ _cleanup()
 {
 	cd /
 	rm -f $tmp.*
+	_btrfs_rescan_devices
 }
 
 # get standard environment, filters and checks
@@ -161,6 +162,7 @@ fi
 
 $UMOUNT_PROG $dev2
 _scratch_dev_pool_put
+_btrfs_rescan_devices
 _test_mount
 
 status=0

tests/btrfs/163

@@ -26,6 +26,7 @@ _cleanup()
 {
 	cd /
 	rm -f $tmp.*
+	_btrfs_rescan_devices
 }
 
 # get standard environment, filters and checks
@@ -102,6 +103,7 @@ replace_sprout
 seed_is_mountable
 
 _scratch_dev_pool_put
+_btrfs_rescan_devices
 
 status=0
 exit

tests/btrfs/164

@@ -22,6 +22,7 @@ _cleanup()
 {
 	cd /
 	rm -f $tmp.*
+	_btrfs_rescan_devices
 }
 
 # get standard environment, filters and checks
@@ -90,6 +91,7 @@ delete_seed
 seed_is_mountable
 
 _scratch_dev_pool_put
+_btrfs_rescan_devices
 
 status=0
 exit

tests/btrfs/219

@@ -35,6 +35,7 @@ _cleanup()
 	[ ! -z "$fs_img1" ] && rm -rf $fs_img1
 	[ ! -z "$fs_img2" ] && rm -rf $fs_img2
 	[ ! -z "$loop_dev" ] && _destroy_loop_device $loop_dev
+	_btrfs_rescan_devices
 }
 
 # get standard environment, filters and checks
@@ -97,6 +98,7 @@ _mount $loop_dev $loop_mnt > /dev/null 2>&1 || \
 _mount -o loop $fs_img2 $loop_mnt1 > /dev/null 2>&1 && \
 	_fail "We were allowed to mount when we should have failed"
 
+_btrfs_rescan_devices
 # success, all done
 echo "Silence is golden"
 status=0

tests/btrfs/225

@@ -25,6 +25,7 @@ _cleanup()
 {
 	cd /
 	rm -f $tmp.*
+	_btrfs_rescan_devices
 }
 
 # get standard environment, filters and checks
@@ -40,6 +41,7 @@ rm -f $seqres.full
 _supported_fs btrfs
 _require_test
 _require_scratch_dev_pool 2
+_require_btrfs_forget_or_module_loadable
 
 _scratch_dev_pool_get 2
 
@@ -76,6 +78,7 @@ od -x $SCRATCH_MNT/foo
 od -x $SCRATCH_MNT/bar
 
 _scratch_dev_pool_put
+_btrfs_rescan_devices
 
 # success, all done
 status=0