Am 24.10.2012 00:19, schrieb Theodore Ts'o: > [...] > The reason why the problem happens rarely is that the effect of the > buggy commit is that if the journal's starting block is zero, we fail > to truncate the journal when we unmount the file system. This can > happen if we mount and then unmount the file system fairly quickly, > before the log has a chance to wrap. After the first time this has > happened, it's not a disaster, since when we replay the journal, we'll > just replay some extra transactions. But if this happens twice, the > oldest valid transaction will still not have gotten updated, but some > of the newer transactions from the last mount session will have gotten > written by the very latest transacitons, and when we then try to do > the extra transaction replays, the metadata blocks can end up getting > very scrambled indeed. > [...] As a "normal linux user" I'm interested in the practical things to do now to avoid data loss. I'm running several systems with 3.6.2 and ext4. Fearing loss of data: - Is there a way to see whether the journal of a specific partition has been wrapped (since mounting) so that umounting and mounting (or doing a reboot to downgrade the kernel) is safe? - Is there a way to "force" a journal-wrap? Run any filesystem-benchmark? Which one with what parameters? Or is it unwise since I might even further corrupt data if I hit the case already? - Is it wise to umount now and run e2fsck or might I corrupt my files just by umounting now if the journal hasn't wrapped yet? - How do you define "fairly quickly"? Of course servers run 24/7 but I might be using my PC 2-5 hrs a day... Is that a "reboot to soon after booting"? - Any more advice you can give to the ordinary user to avoid fs-corruption? Don't shut down machines for some days? Better down- or upgrade the kernel? Best regards, Jannis Achstetter -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
