LWN.net's Journal

[$] The Btrfs inode-number epic (part 2: solutions)
The first installment in this two-part
series looked at the difficulties that arise when Btrfs filesystems
containing subvolumes are exported via NFS. Btrfs has a couple of quirks
that complicate life in this situation: the use of separate device numbers
for subvolumes and the lack of unique inode numbers across the filesystem
as a whole. Recently, Neil Brown set off on an effort to try
to solve these problems, only to discover that the situation was even
more difficult than expected and that many attempts would be required.