Hi, > Is there a race in there? It seems like if a process starts > modifying a file between the sync and the snapshot, data could > still be lost. Is there something else going on here that I'm > missing that would prevent this race?
AIUI, you're correct that a writer process concurrent to a snapshot leads to a race with data that doesn't make it in to the snapshot, but I think you're wrong in thinking that there's much we could do about it -- either you miss writes between sync and snapshot, as we do now, or we do sync-and-snapshot atomically, and the concurrent writes are missed because we decided to block further writes from that process before we took the snapshot. The only real answer is to quiesce the writer process before you begin. Does that make sense? - Chris. -- Chris Ball <c...@laptop.org> One Laptop Per Child -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
