ext4: do not allow journal_opts for fs w/o journal

It is appeared that we can pass journal related mount options and such options
be shown in /proc/mounts

Example:
#mkfs.ext4 -F /dev/vdb
#tune2fs -O ^has_journal /dev/vdb
#mount /dev/vdb /mnt/  -ocommit=20,journal_async_commit
#cat /proc/mounts  | grep /mnt
 /dev/vdb /mnt ext4 rw,relatime,journal_checksum,journal_async_commit,commit=20,data=ordered 0 0

But options:"journal_checksum,journal_async_commit,commit=20,data=ordered" has
nothing with reality because there is no journal at all.

This patch disallow following options for journalless configurations:
 - journal_checksum
 - journal_async_commit
 - commit=%ld
 - data={writeback,ordered,journal}

Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index b1d04aa7..750063f 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1023,6 +1023,9 @@
 #define EXT4_MOUNT2_HURD_COMPAT		0x00000004 /* Support HURD-castrated
 						      file systems */
 
+#define EXT4_MOUNT2_EXPLICIT_JOURNAL_CHECKSUM	0x00000008 /* User explicitly
+						specified journal checksum */
+
 #define clear_opt(sb, opt)		EXT4_SB(sb)->s_mount_opt &= \
 						~EXT4_MOUNT_##opt
 #define set_opt(sb, opt)		EXT4_SB(sb)->s_mount_opt |= \