sk-unix: Don't fail if socket path lays on btrfs volume

Because socket migh lay on btrfs volume (thus the device
number reported by diag module won't be the same as obtained
from stat(2)) we need to do an additional test and try
to resolve device number with help of btrfs engine.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

sk-unix.c

@@ -355,7 +355,7 @@ static int unix_collect_one(const struct unix_diag_msg *m,
 			}
 
 			if ((st.st_ino != uv->udiag_vfs_ino) ||
-			    (st.st_dev != kdev_to_odev(uv->udiag_vfs_dev))) {
+			    !phys_stat_dev_match(st.st_dev, kdev_to_odev(uv->udiag_vfs_dev))) {
 				pr_info("unix: Dropping path %s for "
 						"unlinked bound "
 						"sk %#x.%#x real %#x.%#x\n",