[PATCH v5 01/10] fstests: sanity check that test partitions are not mounted elsewhere

[Amir Goldstein <amir73il@gmail.com>]

When $TEST_DEV is mounted at a different location then $TEST_DIR,
_require_test() aborts the test with an error:
 TEST_DEV=/dev/sda5 is mounted but not on TEST_DIR=/mnt/test

There are several problems with current sanity check:
1. the output of the error is mixed into out.bad and hard to see
2. the test partition is unmounted at the end of the test regardless
   of the fact that it not pass the sanity that we have exclusivity
3. scratch partition has a similar sanity check in _require_scratch(),
   but we may not get to it, because $SCRATCH_DEV is unmounted prior
   to running the tests (which could unmount another mount point).

To solve all these problems, introduce a helper _check_mounted_on().
It checks if a device is mounted on a given mount point and optionally
checks the mounted fs type.

The sanity checks in _require_scratch() and _require_test() are
converted to use the helper and gain the check for correct fs type.

The helper is used in init_rc() to sanity check both test and scratch
partitions, before tests are run and before $SCRATCH_DEV is unmounted.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
---
 common/rc | 90 +++++++++++++++++++++++++++++++++++++++------------------------
 1 file changed, 56 insertions(+), 34 deletions(-)

diff --git a/common/rc b/common/rc
index 8f23334..dab3cb2 100644
--- a/common/rc
+++ b/common/rc
@@ -1354,6 +1354,43 @@ _supported_os()
     _notrun "not suitable for this OS: $HOSTOS"
 }
 
+# check if a FS on a device is mounted
+# if so, verify that it is mounted on mount point
+# if fstype is given as argument, verify that it is also
+# mounted with correct fs type
+#
+_check_mounted_on()
+{
+	local devname=$1
+	local dev=$2
+	local mntname=$3
+	local mnt=$4
+	local type=$5
+
+	# Note that we use -F here so grep doesn't try to interpret an NFS over
+	# IPv6 server as a regular expression
+	local mount_rec=`_mount | grep -F "$dev"`
+	[ -n "$mount_rec" ] || return 1 # 1 = not mounted
+
+	# if it's mounted, make sure its on $mnt
+	if ! (echo $mount_rec | grep -q "$mnt")
+	then
+		echo "$devname=$dev is mounted but not on $mntname=$mnt - aborting"
+		echo "Already mounted result:"
+		echo $mount_rec
+		return 2 # 2 = mounted on wrong mnt
+	fi
+
+	if [ -n "$type" -a "`_fs_type $dev`" != "$type" ]
+	then
+		echo "$devname=$dev is mounted but not a type $type filesystem"
+		# raw $DF_PROG cannot handle NFS/CIFS/overlay correctly
+		_df_device $dev
+		return 3 # 3 = mounted as wrong type
+	fi
+	return 0 # 0 = mounted as expected
+}
+
 # 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
@@ -1408,21 +1445,12 @@ _require_scratch_nocheck()
 		 ;;
     esac
 
-    # mounted?
-    # Note that we use -F here so grep doesn't try to interpret an NFS over
-    # IPv6 server as a regular expression.
-    mount_rec=`_mount | grep -F $SCRATCH_DEV`
-    if [ "$mount_rec" ]
+    _check_mounted_on SCRATCH_DEV $SCRATCH_DEV SCRATCH_MNT $SCRATCH_MNT
+    local err=$?
+    [ $err -le 1 ] || exit 1
+    if [ $err -eq 0 ]
     then
-        # if it's mounted, make sure its on $SCRATCH_MNT
-        if ! echo $mount_rec | grep -q $SCRATCH_MNT
-        then
-            echo "\$SCRATCH_DEV=$SCRATCH_DEV is mounted but not on \$SCRATCH_MNT=$SCRATCH_MNT - aborting"
-            echo "Already mounted result:"
-            echo $mount_rec
-            exit 1
-        fi
-        # and then unmount it
+        # if it's mounted, unmount it
         if ! _scratch_unmount
         then
             echo "failed to unmount $SCRATCH_DEV"
@@ -1493,21 +1521,11 @@ _require_test()
 		 ;;
     esac
 
-    # mounted?
-    # Note that we use -F here so grep doesn't try to interpret an NFS over
-    # IPv6 server as a regular expression.
-    mount_rec=`_mount | grep -F $TEST_DEV`
-    if [ "$mount_rec" ]
+    _check_mounted_on TEST_DEV $TEST_DEV TEST_DIR $TEST_DIR
+    local err=$?
+    [ $err -le 1 ] || exit 1
+    if [ $err -ne 0 ]
     then
-        # if it's mounted, make sure its on $TEST_DIR
-        if ! echo $mount_rec | grep -q $TEST_DIR
-        then
-            echo "\$TEST_DEV=$TEST_DEV is mounted but not on \$TEST_DIR=$TEST_DIR - aborting"
-            echo "Already mounted result:"
-            echo $mount_rec
-            exit 1
-        fi
-    else
 	out=`_mount_or_remount_rw "$MOUNT_OPTIONS" $TEST_DEV $TEST_DIR`
 	if [ $? -ne 1 ]; then
 		echo $out
@@ -3132,13 +3150,17 @@ init_rc()
 		fi
 	fi
 
-	if [ "`_fs_type $TEST_DEV`" != "$FSTYP" ]
-	then
-		echo "common/rc: Error: \$TEST_DEV ($TEST_DEV) is not a MOUNTED $FSTYP filesystem"
-		# raw $DF_PROG cannot handle NFS/CIFS/overlay correctly
-		_df_device $TEST_DEV
-		exit 1
+	# Sanity check that TEST partition is not mounted at another mount point
+	# or as another fs type
+	_check_mounted_on TEST_DEV $TEST_DEV TEST_DIR $TEST_DIR $FSTYP || exit 1
+	if [ -n "$SCRATCH_DEV" ]; then
+		# Sanity check that SCRATCH partition is not mounted at another
+		# mount point, because it is about to be unmounted and formatted.
+		# Another fs type for scratch is fine (bye bye old fs type).
+		_check_mounted_on SCRATCH_DEV $SCRATCH_DEV SCRATCH_MNT $SCRATCH_MNT
+		[ $? -le 1 ] || exit 1
 	fi
+
 	# Figure out if we need to add -F ("foreign", deprecated) option to xfs_io
 	$XFS_IO_PROG -c stat $TEST_DIR 2>&1 | grep -q "is not on an XFS filesystem" && \
 		export XFS_IO_PROG="$XFS_IO_PROG -F"
-- 
2.7.4