tests: add regression tests for MMP blocks with bad checksums

Add regression tests to examine how e2fsck deals with MMP blocks with
(a) a bad magic number; and (b) an incorrect checksum.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

e2fsck/unix.c

@@ -1166,7 +1166,9 @@ check_error:
 			ext2fs_mmp_clear(fs);
 			retval = 0;
 		}
-	}
+	} else
+		com_err(ctx->program_name, retval, "%s",
+			_("while reading MMP block"));
 	return retval;
 }
 

tests/m_mmp_bad_csum/expect

@@ -0,0 +1,9 @@
+Superblock MMP block checksum does not match MMP block.  Fix? yes
+
+Pass 1: Checking inodes, blocks, and sizes
+Pass 2: Checking directory structure
+Pass 3: Checking directory connectivity
+Pass 4: Checking reference counts
+Pass 5: Checking group summary information
+test_filesys: 11/128 files (0.0% non-contiguous), 19/512 blocks
+Exit status is 0

tests/m_mmp_bad_csum/name

@@ -0,0 +1 @@
+mmp with bad csum (metadata_csum)

tests/m_mmp_bad_csum/script

@@ -0,0 +1,30 @@
+# use current directory instead of /tmp becase tmpfs doesn't support DIO
+rm -f $TMPFILE
+TMPFILE=$(mktemp ./tmp-$test_name.XXXXXX)
+
+stat -f $TMPFILE | grep -q "Type: tmpfs"
+if [ $? = 0 ]; then
+	rm -f $TMPFILE
+	echo "$test_name: $test_description: skipped for tmpfs (no O_DIRECT)"
+	return 0
+fi
+gzip -dc < $test_dir/image.gz > $TMPFILE
+
+OUT=$test_dir.log
+EXP=$test_dir/expect
+$FSCK -fy $TMPFILE 2>&1 | sed -f $cmd_dir/filter.sed > $OUT
+echo Exit status is $? >> $OUT
+
+rm -f $TMPFILE
+cmp -s $OUT $EXP
+status=$?
+
+if [ "$status" = 0 ] ; then
+	echo "$test_name: $test_description: ok"
+	touch $test_name.ok
+else
+	echo "$test_name: $test_description: failed"
+	diff $DIFF_OPTS $EXP $OUT > $test_name.failed
+	rm -f $test_name.tmp
+fi
+unset OUT EXP

tests/m_mmp_bad_magic/.log

@@ -0,0 +1,9 @@
+Superblock has invalid MMP magic.  Fix? yes
+
+Pass 1: Checking inodes, blocks, and sizes
+Pass 2: Checking directory structure
+Pass 3: Checking directory connectivity
+Pass 4: Checking reference counts
+Pass 5: Checking group summary information
+test_filesys: 11/128 files (0.0% non-contiguous), 19/512 blocks
+Exit status is 0

tests/m_mmp_bad_magic/expect

@@ -0,0 +1,9 @@
+Superblock has invalid MMP magic.  Fix? yes
+
+Pass 1: Checking inodes, blocks, and sizes
+Pass 2: Checking directory structure
+Pass 3: Checking directory connectivity
+Pass 4: Checking reference counts
+Pass 5: Checking group summary information
+test_filesys: 11/128 files (0.0% non-contiguous), 19/512 blocks
+Exit status is 0

tests/m_mmp_bad_magic/name

@@ -0,0 +1 @@
+mmp with bad magic (metadata_csum)

tests/m_mmp_bad_magic/script

@@ -0,0 +1,30 @@
+# use current directory instead of /tmp becase tmpfs doesn't support DIO
+rm -f $TMPFILE
+TMPFILE=$(mktemp ./tmp-$test_name.XXXXXX)
+
+stat -f $TMPFILE | grep -q "Type: tmpfs"
+if [ $? = 0 ]; then
+	rm -f $TMPFILE
+	echo "$test_name: $test_description: skipped for tmpfs (no O_DIRECT)"
+	return 0
+fi
+gzip -dc < $test_dir/image.gz > $TMPFILE
+
+OUT=$test_dir.log
+EXP=$test_dir/expect
+$FSCK -fy $TMPFILE 2>&1 | sed -f $cmd_dir/filter.sed > $OUT
+echo Exit status is $? >> $OUT
+
+rm -f $TMPFILE
+cmp -s $OUT $EXP
+status=$?
+
+if [ "$status" = 0 ] ; then
+	echo "$test_name: $test_description: ok"
+	touch $test_name.ok
+else
+	echo "$test_name: $test_description: failed"
+	diff $DIFF_OPTS $EXP $OUT > $test_name.failed
+	rm -f $test_name.tmp
+fi
+unset OUT EXP