Which of the following Linux file systems is a journaled file system?

ext3 added a dedicated journal to the ext2 filesystem structure that logs metadata operations before they are applied to the main filesystem. This write-ahead logging allows the kernel to replay or discard incomplete transactions after an unclean shutdown, enabling fast and consistent recovery without a full disk scan.

ext4 is also a journaled filesystem and inherits ext3's journaling capability while adding features like extents and larger volume support, but the question targets ext3 as the original journaled member of the ext family.

ext2 is a non-journaled filesystem; after a crash it requires a full fsck consistency check rather than a journal replay, making recovery significantly slower and more error-prone.

The original ext filesystem is an early, deprecated Linux filesystem that predates journaling support and lacks the reliability features of its successors.