From: Yan, Zheng <zyan@xxxxxxxxxx> commit 37659182bff1eeaaeadcfc8f853c6d2b6dbc3f47 upstream. We missed two places that i_wrbuffer_ref_head, i_wr_ref, i_dirty_caps and i_flushing_caps may change. When they are all zeros, we should free i_head_snapc. Cc: stable@xxxxxxxxxxxxxxx Link: https://tracker.ceph.com/issues/38224 Reported-and-tested-by: Luis Henriques <lhenriques@xxxxxxxx> Signed-off-by: "Yan, Zheng" <zyan@xxxxxxxxxx> Signed-off-by: Ilya Dryomov <idryomov@xxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- fs/ceph/mds_client.c | 9 +++++++++ fs/ceph/snap.c | 7 ++++++- 2 files changed, 15 insertions(+), 1 deletion(-) --- a/fs/ceph/mds_client.c +++ b/fs/ceph/mds_client.c @@ -1290,6 +1290,15 @@ static int remove_session_caps_cb(struct list_add(&ci->i_prealloc_cap_flush->i_list, &to_remove); ci->i_prealloc_cap_flush = NULL; } + + if (drop && + ci->i_wrbuffer_ref_head == 0 && + ci->i_wr_ref == 0 && + ci->i_dirty_caps == 0 && + ci->i_flushing_caps == 0) { + ceph_put_snap_context(ci->i_head_snapc); + ci->i_head_snapc = NULL; + } } spin_unlock(&ci->i_ceph_lock); while (!list_empty(&to_remove)) { --- a/fs/ceph/snap.c +++ b/fs/ceph/snap.c @@ -568,7 +568,12 @@ void ceph_queue_cap_snap(struct ceph_ino old_snapc = NULL; update_snapc: - if (ci->i_head_snapc) { + if (ci->i_wrbuffer_ref_head == 0 && + ci->i_wr_ref == 0 && + ci->i_dirty_caps == 0 && + ci->i_flushing_caps == 0) { + ci->i_head_snapc = NULL; + } else { ci->i_head_snapc = ceph_get_snap_context(new_snapc); dout(" new snapc is %p\n", new_snapc); }
