On 08/19/2017 12:19 AM, Goffredo Baroncelli wrote: >> We have no way of making sure nobody >> touches the page while we're writing it out, so after we calculate the >> checksum >> any changes to the page are going to cause a checksum mismatch. O_DIRECT are >> user space pages, there's nothing we can do to stop user space from doing >> stupid >> things. > I understand the technical difficulties;
I looked how ZFS deal with this problem. According of this thread [1] it seems that currently ZFS (on linux) doesn't support O_DIRECT. In this thread it is mentioned that one of the problem is the coherency between data and checksum. I think that it is better to not support O_DIRECT for cow files than having mismatched checksum.. BR G.Baroncelli [1] https://github.com/zfsonlinux/zfs/issues/224 -- gpg @keyserver.linux.it: Goffredo Baroncelli <kreijackATinwind.it> Key fingerprint BBF5 1610 0B64 DAC6 5F7D 17B2 0EDA 9B37 8B82 E0B5 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
