On Mon, Oct 06, 2008 at 02:37:54PM -0700, Joel Becker wrote: > On Fri, Oct 03, 2008 at 08:03:36PM -0400, Theodore Tso wrote: > Now, I'm sure this is the buffer that's going to the journal, I > think you're saying that this buffer may not be what gets checkpointed. > So the correct checksum hits the journal, but then an invalid one gets > to the real location on disk. Is that right? If so, I need to figure > out where to calculate the checksum somewhere higher, as you say. Ok, looking at your first email again, you're saying to move up to the "Check for escaping" section. There we might checksum b_data before it's copied out. This is, indeed, safe against the problem you mentioned. I also think it's safe to checksum b_frozen_data if already set there, as that's a frozen for commit buffer. Can I trust that checksumming b_data there will not be overwritten by another process doing journal_dirty_metadata() before we write out our buffer? Can I trust that the b_frozen_data, if already copied, will be the buffer committed and checkpointed? If so, I think that change works. Joel -- "What no boss of a programmer can ever understand is that a programmer is working when he's staring out of the window" - With apologies to Burton Rascoe Joel Becker Principal Software Developer Oracle E-mail: joel.becker@xxxxxxxxxx Phone: (650) 506-8127 -- 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
