Hello everyone, After googled a bit, I got information that btrfs supports FIEMAP (as "cp" needs it), but it's not valid for "write" operation.
I guess we cannot write to block device directly after get block list using FIEMAP. This is because: 1. COW feature of btrfs (but this can be disabled using NOCOW) 2. File system rebalance 3. Defragmentation Aren't item #2 and #3 also a problem for "read" operation? For example, after "cp" get block list using FIEMAP, file system rebalance occurs, So, previous result of FIEMAP is not valid anymore. Or maybe I misunderstood something. Please correct me. Thanks Mike -- 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
