> Sent: Tuesday, March 06, 2018 at 4:22 PM
> From: "Yan, Zheng" <ukernel@xxxxxxxxx>
> To: "Chengguang Xu" <cgxu519@xxxxxxxxxx>
> Cc: "Yan, Zheng" <zyan@xxxxxxxxxx>, "Ceph Development" <ceph-devel@xxxxxxxxxxxxxxx>, "Ilya Dryomov" <idryomov@xxxxxxxxx>, cgxu519@xxxxxxx
> Subject: Re: [PATCH] ceph: check return value of ceph_get_cap()
>
> On Tue, Mar 6, 2018 at 12:22 PM, Chengguang Xu <cgxu519@xxxxxxxxxx> wrote:
> > Hi Yan,
> >
> > Any objection for this?
> >
>
> Failing to record a cap from mds is serious problem. It may hang the
> mds. I'd like to kill the whole mount in this case.
How about calling panic() instead of working continuously?
>
> >> 在 2018年2月24日，下午6:34，Chengguang Xu <cgxu519@xxxxxxxxxx> 写道：
> >>
> >> ceph_get_cap() can return NULL, so should check return value carefully
> >> in case of using NULL pointer unexpectedly.
> >>
> >> Signed-off-by: Chengguang Xu <cgxu519@xxxxxxxxxx>
> >> ---
> >> Only compile tested.
> >>
> >> fs/ceph/caps.c | 10 ++++++++++
> >> 1 file changed, 10 insertions(+)
> >>
> >> diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
> >> index 6582c45..9ef40ae 100644
> >> --- a/fs/ceph/caps.c
> >> +++ b/fs/ceph/caps.c
> >> @@ -3510,6 +3510,10 @@ static void handle_cap_export(struct inode *inode, struct ceph_mds_caps *ex,
> >> } else if (tsession) {
> >> /* add placeholder for the export tagert */
> >> int flag = (cap == ci->i_auth_cap) ? CEPH_CAP_FLAG_AUTH : 0;
> >> +
> >> + if (!new_cap)
> >> + goto out_unlock;
> >> +
> >> tcap = new_cap;
> >> ceph_add_cap(inode, tsession, t_cap_id, -1, issued, 0,
> >> t_seq - 1, t_mseq, (u64)-1, flag, &new_cap);
> >> @@ -3764,6 +3768,11 @@ void ceph_handle_caps(struct ceph_mds_session *session,
> >>
> >> if (op == CEPH_CAP_OP_IMPORT) {
> >> cap = ceph_get_cap(mdsc, NULL);
> >> + if (!cap) {
> >> + pr_err("%s: can't get cap\n", __func__);
> >> + goto bad_cap;
> >> + }
> >> +
> >> cap->cap_ino = vino.ino;
> >> cap->queue_release = 1;
> >> cap->cap_id = le64_to_cpu(h->cap_id);
> >> @@ -3864,6 +3873,7 @@ void ceph_handle_caps(struct ceph_mds_session *session,
> >>
> >> bad:
> >> pr_err("ceph_handle_caps: corrupt message\n");
> >> +bad_cap:
> >> ceph_msg_dump(msg);
> >> return;
> >> }
> >> --
> >> 1.8.3.1
> >>
> >
> > --
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