Hello, On Fri 16-05-08 19:25:44, Hidehiro Kawai wrote: > Jan Kara wrote: > > > On Wed 14-05-08 13:48:43, Hidehiro Kawai wrote: > > > >>Subject: [PATCH 2/4] jbd: ordered data integrity fix > >> > >>In ordered mode, if a buffer being dirtied exists in the committing > >>transaction, we write the buffer to the disk, move it from the > >>committing transaction to the running transaction, then dirty it. > >>But we don't have to remove the buffer from the committing > >>transaction when the buffer couldn't be written out, otherwise it > >>breaks the ordered mode rule. > > > > Hmm, could you elaborate a bit more what exactly is broken and how does > > this help to fix it? Because even if we find EIO happened on data buffer, > > we currently don't do anything else than just remove the buffer from the > > transaction and abort the journal. And even if we later managed to write > > the data buffer from other process before the journal is aborted, ordered > > mode guarantees are satisfied - we only guarantee that too old data cannot > > be seen, newer can be seen easily... Thanks. > > In the case where I stated the above, error checking is postponed to > the next (currently running) transaction because the buffer is removed > from the committing transaction before checked for an error. This can > happen repeatedly, then the error won't be detected "for a long time". > However, finally the error is detected by, for example, > journal_commit_transaction(), we can abort the journal. So this > problem is not so serious than the other patches which I sent. OK, I see. So I agree with the change but please add this explanation (like: cannot remove buffer with io error from the committing transaction because otherwise it would miss the error and commit would not abort) to the comment in journal_dirty_data(). Thanks. Honza -- Jan Kara <jack@xxxxxxx> SUSE Labs, CR -- 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
