ext4: fix no journal corruption with locale-gen

If there is no journal, ext4_should_writeback_data() should return
TRUE.  This will fix ext4_set_aops() to set ext4_da_ops in the case of
delayed allocation; otherwise ext4_journaled_aops gets used by
default, which doesn't handle delayed allocation properly.

The advantage of using ext4_should_writeback_data() approach is that
it should handle nobh better as well.

Thanks to Curt Wohlgemuth for investigating this problem, and Aneesh
Kumar for suggesting this approach.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

fs/ext4/ext4_jbd2.h

@@ -281,10 +281,10 @@ static inline int ext4_should_order_data(struct inode *inode)
 
 static inline int ext4_should_writeback_data(struct inode *inode)
 {
-	if (EXT4_JOURNAL(inode) == NULL)
-		return 0;
 	if (!S_ISREG(inode->i_mode))
 		return 0;
+	if (EXT4_JOURNAL(inode) == NULL)
+		return 1;
 	if (EXT4_I(inode)->i_flags & EXT4_JOURNAL_DATA_FL)
 		return 0;
 	if (test_opt(inode->i_sb, DATA_FLAGS) == EXT4_MOUNT_WRITEBACK_DATA)