From: Xiubo Li <xiubli@xxxxxxxxxx> commit 4cafd0400bcb6187c0d4ab4d4b0229a89ac4f8c2 upstream. When the MClientSnap reqeust's op is not CEPH_SNAP_OP_SPLIT the request may still contain a list of 'split_realms', and we need to skip it anyway. Or it will be parsed as a corrupt snaptrace. Cc: stable@xxxxxxxxxxxxxxx Link: https://tracker.ceph.com/issues/61200 Reported-by: Frank Schilder <frans@xxxxxx> Signed-off-by: Xiubo Li <xiubli@xxxxxxxxxx> Reviewed-by: Ilya Dryomov <idryomov@xxxxxxxxx> Signed-off-by: Ilya Dryomov <idryomov@xxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- fs/ceph/snap.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) --- a/fs/ceph/snap.c +++ b/fs/ceph/snap.c @@ -1028,6 +1028,19 @@ skip_inode: continue; adjust_snap_realm_parent(mdsc, child, realm->ino); } + } else { + /* + * In the non-split case both 'num_split_inos' and + * 'num_split_realms' should be 0, making this a no-op. + * However the MDS happens to populate 'split_realms' list + * in one of the UPDATE op cases by mistake. + * + * Skip both lists just in case to ensure that 'p' is + * positioned at the start of realm info, as expected by + * ceph_update_snap_trace(). + */ + p += sizeof(u64) * num_split_inos; + p += sizeof(u64) * num_split_realms; } /*
