On Fri, Apr 1, 2011 at 8:40 PM, Chris Mason <chris.mason@xxxxxxxxxx> wrote: > Excerpts from Christoph Hellwig's message of 2011-04-01 09:34:05 -0400: >> I don't think it's a good idea to introduce any user visible operations >> over subvolume boundaries. Currently we don't have any operations over >> mount boundaries, which is pretty fumdamental to the unix filesystem >> semantics. If you want to change this please come up with a clear >> description of the semantics and post it to linux-fsdevel for >> discussion. That of course requires a clear description of the >> btrfs subvolumes, which is still completely missing. >> > > The subvolume is just a directory tree that can be snapshotted, and has > it's own private inode number space. > > reflink across subvolumes is no different from copying a file from one > subvolume to another at the VFS level. The src and destination are > different files and different inodes, they just happen to share data > extents. ... and currently copying file from one subvolume to another requires copying the data as well. It'd be great if you could only copy the metadata. A good possible use that comes to mind is to quickly merge several subvolumes into a new one. -- Fajar -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
