2 files changed, 32 insertions, 2 deletions

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index b1d04aa724be..750063f7a50c 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1023,6 +1023,9 @@ struct ext4_inode_info {
 #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 |= \
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index db4be39a8db7..04d0f1b33409 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1384,10 +1384,10 @@ static const struct mount_opts {
         {Opt_nojournal_checksum, EXT4_MOUNT_JOURNAL_CHECKSUM,
          MOPT_EXT4_ONLY | MOPT_CLEAR},
         {Opt_journal_checksum, EXT4_MOUNT_JOURNAL_CHECKSUM,
-         MOPT_EXT4_ONLY | MOPT_SET},
+         MOPT_EXT4_ONLY | MOPT_SET | MOPT_EXPLICIT},
         {Opt_journal_async_commit, (EXT4_MOUNT_JOURNAL_ASYNC_COMMIT |
                                     EXT4_MOUNT_JOURNAL_CHECKSUM),
-         MOPT_EXT4_ONLY | MOPT_SET},
+         MOPT_EXT4_ONLY | MOPT_SET | MOPT_EXPLICIT},
         {Opt_noload, EXT4_MOUNT_NOLOAD, MOPT_NO_EXT2 | MOPT_SET},
         {Opt_err_panic, EXT4_MOUNT_ERRORS_PANIC, MOPT_SET | MOPT_CLEAR_ERR},
         {Opt_err_ro, EXT4_MOUNT_ERRORS_RO, MOPT_SET | MOPT_CLEAR_ERR},
@@ -1519,6 +1519,8 @@ static int handle_mount_opt(struct super_block *sb, char *opt, int token,
         if (m->flags & MOPT_EXPLICIT) {
                 if (m->mount_opt & EXT4_MOUNT_DELALLOC) {
                         set_opt2(sb, EXPLICIT_DELALLOC);
+                } else if (m->mount_opt & EXT4_MOUNT_JOURNAL_CHECKSUM) {
+                        set_opt2(sb, EXPLICIT_JOURNAL_CHECKSUM);
                 } else
                         return -1;
         }
@@ -3677,6 +3679,31 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
                        "suppressed and not mounted read-only");
                 goto failed_mount_wq;
         } else {
+                /* Nojournal mode, all journal mount options are illegal */
+                if (test_opt2(sb, EXPLICIT_JOURNAL_CHECKSUM)) {
+                        ext4_msg(sb, KERN_ERR, "can't mount with "
+                                 "journal_checksum, fs mounted w/o journal");
+                        goto failed_mount_wq;
+                }
+                if (test_opt(sb, JOURNAL_ASYNC_COMMIT)) {
+                        ext4_msg(sb, KERN_ERR, "can't mount with "
+                                 "journal_async_commit, fs mounted w/o journal");
+                        goto failed_mount_wq;
+                }
+                if (sbi->s_commit_interval != JBD2_DEFAULT_MAX_COMMIT_AGE*HZ) {
+                        ext4_msg(sb, KERN_ERR, "can't mount with "
+                                 "commit=%lu, fs mounted w/o journal",
+                                 sbi->s_commit_interval / HZ);
+                        goto failed_mount_wq;
+                }
+                if (EXT4_MOUNT_DATA_FLAGS &
+                    (sbi->s_mount_opt ^ sbi->s_def_mount_opt)) {
+                        ext4_msg(sb, KERN_ERR, "can't mount with "
+                                 "data=, fs mounted w/o journal");
+                        goto failed_mount_wq;
+                }
+                sbi->s_def_mount_opt &= EXT4_MOUNT_JOURNAL_CHECKSUM;
+                clear_opt(sb, JOURNAL_CHECKSUM);
                 clear_opt(sb, DATA_FLAGS);
                 sbi->s_journal = NULL;
                 needs_recovery = 0;