The EXT4 Corruption Bug Is Fixed


Much ado about an ultimately irrelevant issue: a bug in the ext4 filesystem has turned out only to be exposed when several exotic options are combined. Apparently, the problem has only affected a single user.

The true cause of this EXT4 bug has now been uncovered and patched within the mainline Linux kernel. The EXT4 corruption issue was fixed with this commit and Ted Ts'o describes it as:

This fixes the root cause of the ext4 data corruption bug which raised a ruckus on LWN, Phoronix, and Slashdot.

This bug only showed up when non-standard mount options (journal_async_commit and/or journal_checksum) were enabled, and when the file system was not cleanly unmounted, but the root cause was the inode bitmap modifications was not being properly journaled.

This could potentially lead to minor file system corruptions (pass 5 complaints with the inode allocation bitmap) after an unclean shutdown under the wrong/unlucky workloads, but it turned into major failure if the journal_checksum and/or jouaral_async_commit was enabled.

I already added that patch to our kernels you can install them from our testing repositories. They will land next week in our stable repositories.