ext4: Use bforget() in no journal mode for ext4_journal_{forget,revoke}()

When ext4 is using a journal, a metadata block which is deallocated
must be passed into the journal layer so it can be dropped from the
current transaction and/or revoked.  This is done by calling the
functions ext4_journal_forget() and ext4_journal_revoke(), which call
jbd2_journal_forget(), and jbd2_journal_revoke(), respectively.

Since the jbd2_journal_forget() and jbd2_journal_revoke() call
bforget(), if ext4 is not using a journal, ext4_journal_forget() and
ext4_journal_revoke() must call bforget() to avoid a dirty metadata
block overwriting a block after it has been reallocated and reused for
another inode's data block.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

fs/ext4/ext4_jbd2.c

@@ -44,7 +44,7 @@ int __ext4_journal_forget(const char *where, handle_t *handle,
 						  handle, err);
 	}
 	else
-		brelse(bh);
+		bforget(bh);
 	return err;
 }
 
@@ -60,7 +60,7 @@ int __ext4_journal_revoke(const char *where, handle_t *handle,
 						  handle, err);
 	}
 	else
-		brelse(bh);
+		bforget(bh);
 	return err;
 }