commit 4fbc0c711b2464ee1551850b85002faae0b775d5 upstream.
It's possible to pass the mount helper a server path that has more
than one contiguous slash character. For example:
$ mount -t ceph 192.168.195.165:40176:/// /mnt/cephfs/
In the MDS server side the extra slashes of the server path will be
treated as snap dir, and then we can get the following debug logs:
ceph: mount opening path //
ceph: open_root_inode opening '//'
ceph: fill_trace 0000000059b8a3bc is_dentry 0 is_target 1
ceph: alloc_inode 00000000dc4ca00b
ceph: get_inode created new inode 00000000dc4ca00b 1.ffffffffffffffff ino 1
ceph: get_inode on 1=1.ffffffffffffffff got 00000000dc4ca00b
And then when creating any new file or directory under the mount
point, we can hit the following BUG_ON in ceph_fill_trace():
BUG_ON(ceph_snap(dir) != dvino.snap);
Have the client ignore the extra slashes in the server path when
mounting. This will also canonicalize the path, so that identical mounts
can be consilidated.
1) "//mydir1///mydir//"
2) "/mydir1/mydir"
3) "/mydir1/mydir/"
Regardless of the internal treatment of these paths, the kernel still
stores the original string including the leading '/' for presentation
to userland.
URL: https://tracker.ceph.com/issues/42771
Signed-off-by: Xiubo Li <xiubli@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Luis Henriques <lhenriques@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
9218bca65e