1 files changed, 105 insertions, 70 deletions

diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index c9d2e553a6c4..c681762d76e6 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -547,8 +547,8 @@ void ceph_mdsc_release_request(struct kref *kref)
 		ceph_put_cap_refs(ceph_inode(req->r_inode), CEPH_CAP_PIN);
 		iput(req->r_inode);
 	}
-	if (req->r_locked_dir)
-		ceph_put_cap_refs(ceph_inode(req->r_locked_dir), CEPH_CAP_PIN);
+	if (req->r_parent)
+		ceph_put_cap_refs(ceph_inode(req->r_parent), CEPH_CAP_PIN);
 	iput(req->r_target_inode);
 	if (req->r_dentry)
 		dput(req->r_dentry);
@@ -628,6 +628,9 @@ static void __unregister_request(struct ceph_mds_client *mdsc,
 {
 	dout("__unregister_request %p tid %lld\n", req, req->r_tid);
 
+	/* Never leave an unregistered request on an unsafe list! */
+	list_del_init(&req->r_unsafe_item);
+
 	if (req->r_tid == mdsc->oldest_tid) {
 		struct rb_node *p = rb_next(&req->r_node);
 		mdsc->oldest_tid = 0;
@@ -644,13 +647,15 @@ static void __unregister_request(struct ceph_mds_client *mdsc,
 
 	erase_request(&mdsc->request_tree, req);
 
-	if (req->r_unsafe_dir && req->r_got_unsafe) {
+	if (req->r_unsafe_dir  &&
+	    test_bit(CEPH_MDS_R_GOT_UNSAFE, &req->r_req_flags)) {
 		struct ceph_inode_info *ci = ceph_inode(req->r_unsafe_dir);
 		spin_lock(&ci->i_unsafe_lock);
 		list_del_init(&req->r_unsafe_dir_item);
 		spin_unlock(&ci->i_unsafe_lock);
 	}
-	if (req->r_target_inode && req->r_got_unsafe) {
+	if (req->r_target_inode &&
+	    test_bit(CEPH_MDS_R_GOT_UNSAFE, &req->r_req_flags)) {
 		struct ceph_inode_info *ci = ceph_inode(req->r_target_inode);
 		spin_lock(&ci->i_unsafe_lock);
 		list_del_init(&req->r_unsafe_target_item);
@@ -668,6 +673,28 @@ static void __unregister_request(struct ceph_mds_client *mdsc,
 }
 
 /*
+ * Walk back up the dentry tree until we hit a dentry representing a
+ * non-snapshot inode. We do this using the rcu_read_lock (which must be held
+ * when calling this) to ensure that the objects won't disappear while we're
+ * working with them. Once we hit a candidate dentry, we attempt to take a
+ * reference to it, and return that as the result.
+ */
+static struct inode *get_nonsnap_parent(struct dentry *dentry)
+{
+	struct inode *inode = NULL;
+
+	while (dentry && !IS_ROOT(dentry)) {
+		inode = d_inode_rcu(dentry);
+		if (!inode || ceph_snap(inode) == CEPH_NOSNAP)
+			break;
+		dentry = dentry->d_parent;
+	}
+	if (inode)
+		inode = igrab(inode);
+	return inode;
+}
+
+/*
  * Choose mds to send request to next.  If there is a hint set in the
  * request (e.g., due to a prior forward hint from the mds), use that.
  * Otherwise, consult frag tree and/or caps to identify the
@@ -675,19 +702,6 @@ static void __unregister_request(struct ceph_mds_client *mdsc,
  *
  * Called under mdsc->mutex.
  */
-static struct dentry *get_nonsnap_parent(struct dentry *dentry)
-{
-	/*
-	 * we don't need to worry about protecting the d_parent access
-	 * here because we never renaming inside the snapped namespace
-	 * except to resplice to another snapdir, and either the old or new
-	 * result is a valid result.
-	 */
-	while (!IS_ROOT(dentry) && ceph_snap(d_inode(dentry)) != CEPH_NOSNAP)
-		dentry = dentry->d_parent;
-	return dentry;
-}
-
 static int __choose_mds(struct ceph_mds_client *mdsc,
 			struct ceph_mds_request *req)
 {
@@ -697,7 +711,7 @@ static int __choose_mds(struct ceph_mds_client *mdsc,
 	int mode = req->r_direct_mode;
 	int mds = -1;
 	u32 hash = req->r_direct_hash;
-	bool is_hash = req->r_direct_is_hash;
+	bool is_hash = test_bit(CEPH_MDS_R_DIRECT_IS_HASH, &req->r_req_flags);
 
 	/*
 	 * is there a specific mds we should try?  ignore hint if we have
@@ -717,30 +731,39 @@ static int __choose_mds(struct ceph_mds_client *mdsc,
 	inode = NULL;
 	if (req->r_inode) {
 		inode = req->r_inode;
+		ihold(inode);
 	} else if (req->r_dentry) {
 		/* ignore race with rename; old or new d_parent is okay */
-		struct dentry *parent = req->r_dentry->d_parent;
-		struct inode *dir = d_inode(parent);
+		struct dentry *parent;
+		struct inode *dir;
+
+		rcu_read_lock();
+		parent = req->r_dentry->d_parent;
+		dir = req->r_parent ? : d_inode_rcu(parent);
 
-		if (dir->i_sb != mdsc->fsc->sb) {
-			/* not this fs! */
+		if (!dir || dir->i_sb != mdsc->fsc->sb) {
+			/*  not this fs or parent went negative */
 			inode = d_inode(req->r_dentry);
+			if (inode)
+				ihold(inode);
 		} else if (ceph_snap(dir) != CEPH_NOSNAP) {
 			/* direct snapped/virtual snapdir requests
 			 * based on parent dir inode */
-			struct dentry *dn = get_nonsnap_parent(parent);
-			inode = d_inode(dn);
+			inode = get_nonsnap_parent(parent);
 			dout("__choose_mds using nonsnap parent %p\n", inode);
 		} else {
 			/* dentry target */
 			inode = d_inode(req->r_dentry);
 			if (!inode || mode == USE_AUTH_MDS) {
 				/* dir + name */
-				inode = dir;
+				inode = igrab(dir);
 				hash = ceph_dentry_hash(dir, req->r_dentry);
 				is_hash = true;
+			} else {
+				ihold(inode);
 			}
 		}
+		rcu_read_unlock();
 	}
 
 	dout("__choose_mds %p is_hash=%d (%d) mode %d\n", inode, (int)is_hash,
@@ -769,7 +792,7 @@ static int __choose_mds(struct ceph_mds_client *mdsc,
 				     (int)r, frag.ndist);
 				if (ceph_mdsmap_get_state(mdsc->mdsmap, mds) >=
 				    CEPH_MDS_STATE_ACTIVE)
-					return mds;
+					goto out;
 			}
 
 			/* since this file/dir wasn't known to be
@@ -784,7 +807,7 @@ static int __choose_mds(struct ceph_mds_client *mdsc,
 				     inode, ceph_vinop(inode), frag.frag, mds);
 				if (ceph_mdsmap_get_state(mdsc->mdsmap, mds) >=
 				    CEPH_MDS_STATE_ACTIVE)
-					return mds;
+					goto out;
 			}
 		}
 	}
@@ -797,6 +820,7 @@ static int __choose_mds(struct ceph_mds_client *mdsc,
 		cap = rb_entry(rb_first(&ci->i_caps), struct ceph_cap, ci_node);
 	if (!cap) {
 		spin_unlock(&ci->i_ceph_lock);
+		iput(inode);
 		goto random;
 	}
 	mds = cap->session->s_mds;
@@ -804,6 +828,8 @@ static int __choose_mds(struct ceph_mds_client *mdsc,
 	     inode, ceph_vinop(inode), mds,
 	     cap == ci->i_auth_cap ? "auth " : "", cap);
 	spin_unlock(&ci->i_ceph_lock);
+out:
+	iput(inode);
 	return mds;
 
 random:
@@ -1036,7 +1062,6 @@ static void cleanup_session_requests(struct ceph_mds_client *mdsc,
 	while (!list_empty(&session->s_unsafe)) {
 		req = list_first_entry(&session->s_unsafe,
 				       struct ceph_mds_request, r_unsafe_item);
-		list_del_init(&req->r_unsafe_item);
 		pr_warn_ratelimited(" dropping unsafe request %llu\n",
 				    req->r_tid);
 		__unregister_request(mdsc, req);
@@ -1146,7 +1171,7 @@ static int remove_session_caps_cb(struct inode *inode, struct ceph_cap *cap,
 		ci->i_ceph_flags |= CEPH_I_CAP_DROPPED;
 
 		if (ci->i_wrbuffer_ref > 0 &&
-		    ACCESS_ONCE(fsc->mount_state) == CEPH_MOUNT_SHUTDOWN)
+		    READ_ONCE(fsc->mount_state) == CEPH_MOUNT_SHUTDOWN)
 			invalidate = true;
 
 		while (!list_empty(&ci->i_cap_flush_list)) {
@@ -1775,18 +1800,23 @@ retry:
 	return path;
 }
 
-static int build_dentry_path(struct dentry *dentry,
+static int build_dentry_path(struct dentry *dentry, struct inode *dir,
 			     const char **ppath, int *ppathlen, u64 *pino,
 			     int *pfreepath)
 {
 	char *path;
 
-	if (ceph_snap(d_inode(dentry->d_parent)) == CEPH_NOSNAP) {
-		*pino = ceph_ino(d_inode(dentry->d_parent));
+	rcu_read_lock();
+	if (!dir)
+		dir = d_inode_rcu(dentry->d_parent);
+	if (dir && ceph_snap(dir) == CEPH_NOSNAP) {
+		*pino = ceph_ino(dir);
+		rcu_read_unlock();
 		*ppath = dentry->d_name.name;
 		*ppathlen = dentry->d_name.len;
 		return 0;
 	}
+	rcu_read_unlock();
 	path = ceph_mdsc_build_path(dentry, ppathlen, pino, 1);
 	if (IS_ERR(path))
 		return PTR_ERR(path);
@@ -1822,8 +1852,8 @@ static int build_inode_path(struct inode *inode,
  * an explicit ino+path.
  */
 static int set_request_path_attr(struct inode *rinode, struct dentry *rdentry,
-				  const char *rpath, u64 rino,
-				  const char **ppath, int *pathlen,
+				  struct inode *rdiri, const char *rpath,
+				  u64 rino, const char **ppath, int *pathlen,
 				  u64 *ino, int *freepath)
 {
 	int r = 0;
@@ -1833,7 +1863,8 @@ static int set_request_path_attr(struct inode *rinode, struct dentry *rdentry,
 		dout(" inode %p %llx.%llx\n", rinode, ceph_ino(rinode),
 		     ceph_snap(rinode));
 	} else if (rdentry) {
-		r = build_dentry_path(rdentry, ppath, pathlen, ino, freepath);
+		r = build_dentry_path(rdentry, rdiri, ppath, pathlen, ino,
+					freepath);
 		dout(" dentry %p %llx/%.*s\n", rdentry, *ino, *pathlen,
 		     *ppath);
 	} else if (rpath || rino) {
@@ -1866,7 +1897,7 @@ static struct ceph_msg *create_request_message(struct ceph_mds_client *mdsc,
 	int ret;
 
 	ret = set_request_path_attr(req->r_inode, req->r_dentry,
-			      req->r_path1, req->r_ino1.ino,
+			      req->r_parent, req->r_path1, req->r_ino1.ino,
 			      &path1, &pathlen1, &ino1, &freepath1);
 	if (ret < 0) {
 		msg = ERR_PTR(ret);
@@ -1874,6 +1905,7 @@ static struct ceph_msg *create_request_message(struct ceph_mds_client *mdsc,
 	}
 
 	ret = set_request_path_attr(NULL, req->r_old_dentry,
+			      req->r_old_dentry_dir,
 			      req->r_path2, req->r_ino2.ino,
 			      &path2, &pathlen2, &ino2, &freepath2);
 	if (ret < 0) {
@@ -1927,10 +1959,13 @@ static struct ceph_msg *create_request_message(struct ceph_mds_client *mdsc,
 		      mds, req->r_inode_drop, req->r_inode_unless, 0);
 	if (req->r_dentry_drop)
 		releases += ceph_encode_dentry_release(&p, req->r_dentry,
-		       mds, req->r_dentry_drop, req->r_dentry_unless);
+				req->r_parent, mds, req->r_dentry_drop,
+				req->r_dentry_unless);
 	if (req->r_old_dentry_drop)
 		releases += ceph_encode_dentry_release(&p, req->r_old_dentry,
-		       mds, req->r_old_dentry_drop, req->r_old_dentry_unless);
+				req->r_old_dentry_dir, mds,
+				req->r_old_dentry_drop,
+				req->r_old_dentry_unless);
 	if (req->r_old_inode_drop)
 		releases += ceph_encode_inode_release(&p,
 		      d_inode(req->r_old_dentry),
@@ -2012,7 +2047,7 @@ static int __prepare_send_request(struct ceph_mds_client *mdsc,
 	dout("prepare_send_request %p tid %lld %s (attempt %d)\n", req,
 	     req->r_tid, ceph_mds_op_name(req->r_op), req->r_attempts);
 
-	if (req->r_got_unsafe) {
+	if (test_bit(CEPH_MDS_R_GOT_UNSAFE, &req->r_req_flags)) {
 		void *p;
 		/*
 		 * Replay.  Do not regenerate message (and rebuild
@@ -2061,16 +2096,16 @@ static int __prepare_send_request(struct ceph_mds_client *mdsc,
 
 	rhead = msg->front.iov_base;
 	rhead->oldest_client_tid = cpu_to_le64(__get_oldest_tid(mdsc));
-	if (req->r_got_unsafe)
+	if (test_bit(CEPH_MDS_R_GOT_UNSAFE, &req->r_req_flags))
 		flags |= CEPH_MDS_FLAG_REPLAY;
-	if (req->r_locked_dir)
+	if (req->r_parent)
 		flags |= CEPH_MDS_FLAG_WANT_DENTRY;
 	rhead->flags = cpu_to_le32(flags);
 	rhead->num_fwd = req->r_num_fwd;
 	rhead->num_retry = req->r_attempts - 1;
 	rhead->ino = 0;
 
-	dout(" r_locked_dir = %p\n", req->r_locked_dir);
+	dout(" r_parent = %p\n", req->r_parent);
 	return 0;
 }
 
@@ -2084,8 +2119,8 @@ static int __do_request(struct ceph_mds_client *mdsc,
 	int mds = -1;
 	int err = 0;
 
-	if (req->r_err || req->r_got_result) {
-		if (req->r_aborted)
+	if (req->r_err || test_bit(CEPH_MDS_R_GOT_RESULT, &req->r_req_flags)) {
+		if (test_bit(CEPH_MDS_R_ABORTED, &req->r_req_flags))
 			__unregister_request(mdsc, req);
 		goto out;
 	}
@@ -2096,12 +2131,12 @@ static int __do_request(struct ceph_mds_client *mdsc,
 		err = -EIO;
 		goto finish;
 	}
-	if (ACCESS_ONCE(mdsc->fsc->mount_state) == CEPH_MOUNT_SHUTDOWN) {
+	if (READ_ONCE(mdsc->fsc->mount_state) == CEPH_MOUNT_SHUTDOWN) {
 		dout("do_request forced umount\n");
 		err = -EIO;
 		goto finish;
 	}
-	if (ACCESS_ONCE(mdsc->fsc->mount_state) == CEPH_MOUNT_MOUNTING) {
+	if (READ_ONCE(mdsc->fsc->mount_state) == CEPH_MOUNT_MOUNTING) {
 		if (mdsc->mdsmap_err) {
 			err = mdsc->mdsmap_err;
 			dout("do_request mdsmap err %d\n", err);
@@ -2215,7 +2250,7 @@ static void kick_requests(struct ceph_mds_client *mdsc, int mds)
 	while (p) {
 		req = rb_entry(p, struct ceph_mds_request, r_node);
 		p = rb_next(p);
-		if (req->r_got_unsafe)
+		if (test_bit(CEPH_MDS_R_GOT_UNSAFE, &req->r_req_flags))
 			continue;
 		if (req->r_attempts > 0)
 			continue; /* only new requests */
@@ -2250,11 +2285,11 @@ int ceph_mdsc_do_request(struct ceph_mds_client *mdsc,
 
 	dout("do_request on %p\n", req);
 
-	/* take CAP_PIN refs for r_inode, r_locked_dir, r_old_dentry */
+	/* take CAP_PIN refs for r_inode, r_parent, r_old_dentry */
 	if (req->r_inode)
 		ceph_get_cap_refs(ceph_inode(req->r_inode), CEPH_CAP_PIN);
-	if (req->r_locked_dir)
-		ceph_get_cap_refs(ceph_inode(req->r_locked_dir), CEPH_CAP_PIN);
+	if (req->r_parent)
+		ceph_get_cap_refs(ceph_inode(req->r_parent), CEPH_CAP_PIN);
 	if (req->r_old_dentry_dir)
 		ceph_get_cap_refs(ceph_inode(req->r_old_dentry_dir),
 				  CEPH_CAP_PIN);
@@ -2289,7 +2324,7 @@ int ceph_mdsc_do_request(struct ceph_mds_client *mdsc,
 	mutex_lock(&mdsc->mutex);
 
 	/* only abort if we didn't race with a real reply */
-	if (req->r_got_result) {
+	if (test_bit(CEPH_MDS_R_GOT_RESULT, &req->r_req_flags)) {
 		err = le32_to_cpu(req->r_reply_info.head->result);
 	} else if (err < 0) {
 		dout("aborted request %lld with %d\n", req->r_tid, err);
@@ -2301,10 +2336,10 @@ int ceph_mdsc_do_request(struct ceph_mds_client *mdsc,
 		 */
 		mutex_lock(&req->r_fill_mutex);
 		req->r_err = err;
-		req->r_aborted = true;
+		set_bit(CEPH_MDS_R_ABORTED, &req->r_req_flags);
 		mutex_unlock(&req->r_fill_mutex);
 
-		if (req->r_locked_dir &&
+		if (req->r_parent &&
 		    (req->r_op & CEPH_MDS_OP_WRITE))
 			ceph_invalidate_dir_request(req);
 	} else {
@@ -2323,7 +2358,7 @@ out:
  */
 void ceph_invalidate_dir_request(struct ceph_mds_request *req)
 {
-	struct inode *inode = req->r_locked_dir;
+	struct inode *inode = req->r_parent;
 
 	dout("invalidate_dir_request %p (complete, lease(s))\n", inode);
 
@@ -2379,14 +2414,14 @@ static void handle_reply(struct ceph_mds_session *session, struct ceph_msg *msg)
 	}
 
 	/* dup? */
-	if ((req->r_got_unsafe && !head->safe) ||
-	    (req->r_got_safe && head->safe)) {
+	if ((test_bit(CEPH_MDS_R_GOT_UNSAFE, &req->r_req_flags) && !head->safe) ||
+	    (test_bit(CEPH_MDS_R_GOT_SAFE, &req->r_req_flags) && head->safe)) {
 		pr_warn("got a dup %s reply on %llu from mds%d\n",
 			   head->safe ? "safe" : "unsafe", tid, mds);
 		mutex_unlock(&mdsc->mutex);
 		goto out;
 	}
-	if (req->r_got_safe) {
+	if (test_bit(CEPH_MDS_R_GOT_SAFE, &req->r_req_flags)) {
 		pr_warn("got unsafe after safe on %llu from mds%d\n",
 			   tid, mds);
 		mutex_unlock(&mdsc->mutex);
@@ -2425,10 +2460,10 @@ static void handle_reply(struct ceph_mds_session *session, struct ceph_msg *msg)
 
 
 	if (head->safe) {
-		req->r_got_safe = true;
+		set_bit(CEPH_MDS_R_GOT_SAFE, &req->r_req_flags);
 		__unregister_request(mdsc, req);
 
-		if (req->r_got_unsafe) {
+		if (test_bit(CEPH_MDS_R_GOT_UNSAFE, &req->r_req_flags)) {
 			/*
 			 * We already handled the unsafe response, now do the
 			 * cleanup.  No need to examine the response; the MDS
@@ -2437,7 +2472,6 @@ static void handle_reply(struct ceph_mds_session *session, struct ceph_msg *msg)
 			 * useful we could do with a revised return value.
 			 */
 			dout("got safe reply %llu, mds%d\n", tid, mds);
-			list_del_init(&req->r_unsafe_item);
 
 			/* last unsafe request during umount? */
 			if (mdsc->stopping && !__get_oldest_req(mdsc))
@@ -2446,7 +2480,7 @@ static void handle_reply(struct ceph_mds_session *session, struct ceph_msg *msg)
 			goto out;
 		}
 	} else {
-		req->r_got_unsafe = true;
+		set_bit(CEPH_MDS_R_GOT_UNSAFE, &req->r_req_flags);
 		list_add_tail(&req->r_unsafe_item, &req->r_session->s_unsafe);
 		if (req->r_unsafe_dir) {
 			struct ceph_inode_info *ci =
@@ -2486,7 +2520,7 @@ static void handle_reply(struct ceph_mds_session *session, struct ceph_msg *msg)
 	/* insert trace into our cache */
 	mutex_lock(&req->r_fill_mutex);
 	current->journal_info = req;
-	err = ceph_fill_trace(mdsc->fsc->sb, req, req->r_session);
+	err = ceph_fill_trace(mdsc->fsc->sb, req);
 	if (err == 0) {
 		if (result == 0 && (req->r_op == CEPH_MDS_OP_READDIR ||
 				    req->r_op == CEPH_MDS_OP_LSSNAP))
@@ -2500,7 +2534,8 @@ static void handle_reply(struct ceph_mds_session *session, struct ceph_msg *msg)
 	if (realm)
 		ceph_put_snap_realm(mdsc, realm);
 
-	if (err == 0 && req->r_got_unsafe && req->r_target_inode) {
+	if (err == 0 && req->r_target_inode &&
+	    test_bit(CEPH_MDS_R_GOT_UNSAFE, &req->r_req_flags)) {
 		struct ceph_inode_info *ci = ceph_inode(req->r_target_inode);
 		spin_lock(&ci->i_unsafe_lock);
 		list_add_tail(&req->r_unsafe_target_item, &ci->i_unsafe_iops);
@@ -2508,12 +2543,12 @@ static void handle_reply(struct ceph_mds_session *session, struct ceph_msg *msg)
 	}
 out_err:
 	mutex_lock(&mdsc->mutex);
-	if (!req->r_aborted) {
+	if (!test_bit(CEPH_MDS_R_ABORTED, &req->r_req_flags)) {
 		if (err) {
 			req->r_err = err;
 		} else {
 			req->r_reply =  ceph_msg_get(msg);
-			req->r_got_result = true;
+			set_bit(CEPH_MDS_R_GOT_RESULT, &req->r_req_flags);
 		}
 	} else {
 		dout("reply arrived after request %lld was aborted\n", tid);
@@ -2557,7 +2592,7 @@ static void handle_forward(struct ceph_mds_client *mdsc,
 		goto out;  /* dup reply? */
 	}
 
-	if (req->r_aborted) {
+	if (test_bit(CEPH_MDS_R_ABORTED, &req->r_req_flags)) {
 		dout("forward tid %llu aborted, unregistering\n", tid);
 		__unregister_request(mdsc, req);
 	} else if (fwd_seq <= req->r_num_fwd) {
@@ -2567,7 +2602,7 @@ static void handle_forward(struct ceph_mds_client *mdsc,
 		/* resend. forward race not possible; mds would drop */
 		dout("forward tid %llu to mds%d (we resend)\n", tid, next_mds);
 		BUG_ON(req->r_err);
-		BUG_ON(req->r_got_result);
+		BUG_ON(test_bit(CEPH_MDS_R_GOT_RESULT, &req->r_req_flags));
 		req->r_attempts = 0;
 		req->r_num_fwd = fwd_seq;
 		req->r_resend_mds = next_mds;
@@ -2732,7 +2767,7 @@ static void replay_unsafe_requests(struct ceph_mds_client *mdsc,
 	while (p) {
 		req = rb_entry(p, struct ceph_mds_request, r_node);
 		p = rb_next(p);
-		if (req->r_got_unsafe)
+		if (test_bit(CEPH_MDS_R_GOT_UNSAFE, &req->r_req_flags))
 			continue;
 		if (req->r_attempts == 0)
 			continue; /* only old requests */
@@ -3556,7 +3591,7 @@ void ceph_mdsc_sync(struct ceph_mds_client *mdsc)
 {
 	u64 want_tid, want_flush;
 
-	if (ACCESS_ONCE(mdsc->fsc->mount_state) == CEPH_MOUNT_SHUTDOWN)
+	if (READ_ONCE(mdsc->fsc->mount_state) == CEPH_MOUNT_SHUTDOWN)
 		return;
 
 	dout("sync\n");
@@ -3587,7 +3622,7 @@ void ceph_mdsc_sync(struct ceph_mds_client *mdsc)
  */
 static bool done_closing_sessions(struct ceph_mds_client *mdsc, int skipped)
 {
-	if (ACCESS_ONCE(mdsc->fsc->mount_state) == CEPH_MOUNT_SHUTDOWN)
+	if (READ_ONCE(mdsc->fsc->mount_state) == CEPH_MOUNT_SHUTDOWN)
 		return true;
 	return atomic_read(&mdsc->num_sessions) <= skipped;
 }