Re: [PATCH] ceph: rename get_session and switch to use ceph_get_mds_session

[Xiubo Li <xiubli@xxxxxxxxxx>]

This has some conflicts with the upstream code and posted a V2 to fix it.

Thanks.

On 2019/12/18 20:00, xiubli@xxxxxxxxxx wrote:
> From: Xiubo Li <xiubli@xxxxxxxxxx>
>
> Just in case the session's refcount reach 0 and is releasing, and
> if we get the session without checking it, we may encounter kernel
> crash.
>
> Rename get_session to ceph_get_mds_session and make it global.
>
> Signed-off-by: Xiubo Li <xiubli@xxxxxxxxxx>
> ---
>   fs/ceph/caps.c       |  4 ++--
>   fs/ceph/mds_client.c | 16 ++++++++--------
>   fs/ceph/mds_client.h |  9 ++-------
>   3 files changed, 12 insertions(+), 17 deletions(-)
>
> diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
> index 5c89a915409b..5a828298456a 100644
> --- a/fs/ceph/caps.c
> +++ b/fs/ceph/caps.c
> @@ -812,7 +812,7 @@ int __ceph_caps_issued(struct ceph_inode_info *ci, int *implemented, int mask)
>   		     &ci->vfs_inode, cap, ceph_cap_string(cap->issued));
>   
>   		if (mask >= 0) {
> -			s = get_session(cap->session);
> +			s = ceph_get_mds_session(cap->session);
>   			if (cap == ci->i_auth_cap)
>   				r = revoking;
>   			if (mask & (cap->issued & ~r))
> @@ -907,7 +907,7 @@ int __ceph_caps_issued_mask(struct ceph_inode_info *ci, int mask, int touch,
>   		if (!__cap_is_valid(cap))
>   			continue;
>   
> -		s = get_session(cap->session);
> +		s = ceph_get_mds_session(cap->session);
>   		if ((cap->issued & mask) == mask) {
>   			dout("__ceph_caps_issued_mask ino 0x%lx cap %p issued %s"
>   			     " (mask %s)\n", ci->vfs_inode.i_ino, cap,
> diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
> index 99de89a3a0d3..619b08cba677 100644
> --- a/fs/ceph/mds_client.c
> +++ b/fs/ceph/mds_client.c
> @@ -538,7 +538,7 @@ const char *ceph_session_state_name(int s)
>   	}
>   }
>   
> -static struct ceph_mds_session *get_session(struct ceph_mds_session *s)
> +struct ceph_mds_session *ceph_get_mds_session(struct ceph_mds_session *s)
>   {
>   	if (refcount_inc_not_zero(&s->s_ref)) {
>   		dout("mdsc get_session %p %d -> %d\n", s,
> @@ -571,7 +571,7 @@ struct ceph_mds_session *__ceph_lookup_mds_session(struct ceph_mds_client *mdsc,
>   {
>   	if (mds >= mdsc->max_sessions || !mdsc->sessions[mds])
>   		return NULL;
> -	return get_session(mdsc->sessions[mds]);
> +	return ceph_get_mds_session(mdsc->sessions[mds]);
>   }
>   
>   static bool __have_session(struct ceph_mds_client *mdsc, int mds)
> @@ -2004,7 +2004,7 @@ void ceph_flush_cap_releases(struct ceph_mds_client *mdsc,
>   	if (mdsc->stopping)
>   		return;
>   
> -	get_session(session);
> +	ceph_get_mds_session(session);
>   	if (queue_work(mdsc->fsc->cap_wq,
>   		       &session->s_cap_release_work)) {
>   		dout("cap release work queued\n");
> @@ -2619,7 +2619,7 @@ static void __do_request(struct ceph_mds_client *mdsc,
>   			goto finish;
>   		}
>   	}
> -	req->r_session = get_session(session);
> +	req->r_session = ceph_get_mds_session(session);
>   
>   	dout("do_request mds%d session %p state %s\n", mds, session,
>   	     ceph_session_state_name(session->s_state));
> @@ -3143,7 +3143,7 @@ static void handle_session(struct ceph_mds_session *session,
>   
>   	mutex_lock(&mdsc->mutex);
>   	if (op == CEPH_SESSION_CLOSE) {
> -		get_session(session);
> +		ceph_get_mds_session(session);
>   		__unregister_session(mdsc, session);
>   	}
>   	/* FIXME: this ttl calculation is generous */
> @@ -3818,7 +3818,7 @@ static void check_new_map(struct ceph_mds_client *mdsc,
>   
>   		if (i >= newmap->m_num_mds) {
>   			/* force close session for stopped mds */
> -			get_session(s);
> +			ceph_get_mds_session(s);
>   			__unregister_session(mdsc, s);
>   			__wake_requests(mdsc, &s->s_waiting);
>   			mutex_unlock(&mdsc->mutex);
> @@ -4460,7 +4460,7 @@ void ceph_mdsc_close_sessions(struct ceph_mds_client *mdsc)
>   	mutex_lock(&mdsc->mutex);
>   	for (i = 0; i < mdsc->max_sessions; i++) {
>   		if (mdsc->sessions[i]) {
> -			session = get_session(mdsc->sessions[i]);
> +			session = ceph_get_mds_session(mdsc->sessions[i]);
>   			__unregister_session(mdsc, session);
>   			mutex_unlock(&mdsc->mutex);
>   			mutex_lock(&session->s_mutex);
> @@ -4693,7 +4693,7 @@ static struct ceph_connection *con_get(struct ceph_connection *con)
>   {
>   	struct ceph_mds_session *s = con->private;
>   
> -	if (get_session(s)) {
> +	if (ceph_get_mds_session(s)) {
>   		dout("mdsc con_get %p ok (%d)\n", s, refcount_read(&s->s_ref));
>   		return con;
>   	}
> diff --git a/fs/ceph/mds_client.h b/fs/ceph/mds_client.h
> index 40676c2392cf..37e8798e7408 100644
> --- a/fs/ceph/mds_client.h
> +++ b/fs/ceph/mds_client.h
> @@ -457,15 +457,10 @@ extern const char *ceph_mds_op_name(int op);
>   extern struct ceph_mds_session *
>   __ceph_lookup_mds_session(struct ceph_mds_client *, int mds);
>   
> -static inline struct ceph_mds_session *
> -ceph_get_mds_session(struct ceph_mds_session *s)
> -{
> -	refcount_inc(&s->s_ref);
> -	return s;
> -}
> -
>   extern const char *ceph_session_state_name(int s);
>   
> +extern struct ceph_mds_session *
> +ceph_get_mds_session(struct ceph_mds_session *s);
>   extern void ceph_put_mds_session(struct ceph_mds_session *s);
>   
>   extern int ceph_send_msg_mds(struct ceph_mds_client *mdsc,