On Wed, Jun 7, 2023 at 4:57 AM xiubli@redhat.com wrote:
From: Xiubo Li xiubli@redhat.com
There is a race between capsnaps flush and removing the inode from 'mdsc->snap_flush_list' list:
== Thread A == == Thread B == ceph_queue_cap_snap() -> allocate 'capsnapA' ->ihold('&ci->vfs_inode') ->add 'capsnapA' to 'ci->i_cap_snaps' ->add 'ci' to 'mdsc->snap_flush_list' ... == Thread C == ceph_flush_snaps() ->__ceph_flush_snaps() ->__send_flush_snap() handle_cap_flushsnap_ack() ->iput('&ci->vfs_inode') this also will release 'ci' ... == Thread D == ceph_handle_snap() ->flush_snaps() ->iterate 'mdsc->snap_flush_list' ->get the stale 'ci' ->remove 'ci' from ->ihold(&ci->vfs_inode) this 'mdsc->snap_flush_list' will WARNING
To fix this we will increase the inode's i_count ref when adding 'ci' to the 'mdsc->snap_flush_list' list.
Cc: stable@vger.kernel.org URL: https://bugzilla.redhat.com/show_bug.cgi?id=2209299 Reviewed-by: Milind Changire mchangir@redhat.com Signed-off-by: Xiubo Li xiubli@redhat.com
V4:
- s/put/need_put/
Hi Xiubo,
The other part of the suggestion was to make it a bool. I made the adjustment and queued up this patch for 6.4-rc6.
Thanks,
Ilya