ocfs2: punch hole should return EINVAL if the length argument in ioctl is negative

An unreserve space ioctl OCFS2_IOC_UNRESVSP/64 should reject a negative
length.

Orabug:14789508
Signed-off-by: NTariq Saseed <tariq.x.saeed@oracle.com>
Signed-off-by: NSrinivas Eeda <srinivas.eeda@oracle.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Mark Fasheh <mfasheh@suse.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

fs/ocfs2/file.c

@@ -1869,7 +1869,8 @@ static int __ocfs2_change_file_space(struct file *file, struct inode *inode,
 	}
 	size = sr->l_start + sr->l_len;
 
-	if (cmd == OCFS2_IOC_RESVSP || cmd == OCFS2_IOC_RESVSP64) {
+	if (cmd == OCFS2_IOC_RESVSP || cmd == OCFS2_IOC_RESVSP64 ||
+	    cmd == OCFS2_IOC_UNRESVSP || cmd == OCFS2_IOC_UNRESVSP64) {
 		if (sr->l_len <= 0) {
 			ret = -EINVAL;
 			goto out_inode_unlock;