Excerpts from Al Viro's message of 2011-03-04 12:13:53 -0500:

    a) rename() plays with i_nlink of old_inode; bad, since it's not
locked.  I'd add a variant of btrfs_unlink_inode() that would leave
btrfs_drop_nlink()/btrfs_update_inode() to callers and use it instead.
    b) btrfs_link() doesn't check for i_nlink overflows.  I don't
know if there's anything preventing that many links to a file on btrfs,
but if there is, it's at least worth a comment in there...

    Please, review; patches in followups or in #btrfs in vfs-2.6.git

Thanks, these both look good but I'll test here as well.  Are you
planning on pushing for .38?

-chris