On Mon, Jul 01, 2013 at 10:13:26PM +0800, Liu Bo wrote: > For partial extents, snapshot-aware defrag does not work as expected, > since > a) we use the wrong logical offset to search for parents, which should be > disk_bytenr + extent_offset, not just disk_bytenr, > b) 'offset' returned by the backref walking just refers to key.offset, not > the 'offset' stored in btrfs_extent_data_ref which is > (key.offset - extent_offset). > > The reproducer: > $ mkfs.btrfs sda > $ mount sda /mnt > $ btrfs sub create /mnt/sub > $ for i in `seq 5 -1 1`; do dd if=/dev/zero of=/mnt/sub/foo bs=5k count=1 > seek=$i conv=notrunc oflag=sync; done > $ btrfs sub snap /mnt/sub /mnt/snap1 > $ btrfs sub snap /mnt/sub /mnt/snap2 > $ sync; btrfs filesystem defrag /mnt/sub/foo; > $ umount /mnt > $ btrfs-debug-tree sda (Here we can check whether the defrag operation is > snapshot-awared. > > This addresses the above two problems. >
Can this be turned into a xfstest somehow? Like do fiemap and make sure the block numbers match up right? Thanks, Josef -- 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
