[PATCH 0/2] Fix hardlinks in overlay

[Alexander Morozov <alexandr.morozov@docker.com>]

There were reports that overlay doesn't work very well with unix-sockets.
In particular you can't access unix-socket through hardlink on overlay fs.
Problem is that overlay creates different inodes for hardlinks and code in
net/unix/af_unix.c relies on inodes for unix-socket lookup. I think this
affects any code which relies on inodes from kern_path. There is helper
d_backing_inode, which I think supposed to get inodes from underlying fs
(for example ext4), but in current implementation it does nothing.  These
patches made on top of v4.3-rc4 of main linux tree (master is broken for my
ubuntu VM), but I tested that they applying on master and there was no
changes to overlay since v4.3-rc4.

Alexander Morozov (2):
  fs/overlay: move update and instantiate dentry code to function
  fs/overlay: use same inodes for hardlinks

 fs/overlayfs/dir.c | 41 +++++++++++++++++++++++++++++------------
 1 file changed, 29 insertions(+), 12 deletions(-)

-- 
2.6.1