Merge branch 'for-3.18' of git://linux-nfs.org/~bfields/linux

Pull nfsd bugfixes from Bruce Fields:
 "These fix one mishandling of the case when security labels are
  configured out, and two races in the 4.1 backchannel code"

* 'for-3.18' of git://linux-nfs.org/~bfields/linux:
  nfsd: Fix slot wake up race in the nfsv4.1 callback code
  SUNRPC: Fix locking around callback channel reply receive
  nfsd: correctly define v4.2 support attributes

Author: torvalds

fs/nfsd/nfs4callback.c

@@ -774,8 +774,12 @@ static bool nfsd41_cb_get_slot(struct nfs4_client *clp, struct rpc_task *task)
 {
 	if (test_and_set_bit(0, &clp->cl_cb_slot_busy) != 0) {
 		rpc_sleep_on(&clp->cl_cb_waitq, task, NULL);
-		dprintk("%s slot is busy\n", __func__);
-		return false;
+		/* Race breaker */
+		if (test_and_set_bit(0, &clp->cl_cb_slot_busy) != 0) {
+			dprintk("%s slot is busy\n", __func__);
+			return false;
+		}
+		rpc_wake_up_queued_task(&clp->cl_cb_waitq, task);
 	}
 	return true;
 }

fs/nfsd/nfsd.h

@@ -335,12 +335,15 @@ void		nfsd_lockd_shutdown(void);
 	(NFSD4_SUPPORTED_ATTRS_WORD2 | FATTR4_WORD2_SUPPATTR_EXCLCREAT)
 
 #ifdef CONFIG_NFSD_V4_SECURITY_LABEL
-#define NFSD4_2_SUPPORTED_ATTRS_WORD2 \
-	(NFSD4_1_SUPPORTED_ATTRS_WORD2 | FATTR4_WORD2_SECURITY_LABEL)
+#define NFSD4_2_SECURITY_ATTRS		FATTR4_WORD2_SECURITY_LABEL
 #else
-#define NFSD4_2_SUPPORTED_ATTRS_WORD2 0
+#define NFSD4_2_SECURITY_ATTRS		0
 #endif
 
+#define NFSD4_2_SUPPORTED_ATTRS_WORD2 \
+	(NFSD4_1_SUPPORTED_ATTRS_WORD2 | \
+	NFSD4_2_SECURITY_ATTRS)
+
 static inline u32 nfsd_suppattrs0(u32 minorversion)
 {
 	return minorversion ? NFSD4_1_SUPPORTED_ATTRS_WORD0

net/sunrpc/svcsock.c

@@ -1019,17 +1019,12 @@ static int receive_cb_reply(struct svc_sock *svsk, struct svc_rqst *rqstp)
 	xid = *p++;
 	calldir = *p;
 
-	if (bc_xprt)
-		req = xprt_lookup_rqst(bc_xprt, xid);
-
-	if (!req) {
-		printk(KERN_NOTICE
-			"%s: Got unrecognized reply: "
-			"calldir 0x%x xpt_bc_xprt %p xid %08x\n",
-			__func__, ntohl(calldir),
-			bc_xprt, ntohl(xid));
+	if (!bc_xprt)
 		return -EAGAIN;
-	}
+	spin_lock_bh(&bc_xprt->transport_lock);
+	req = xprt_lookup_rqst(bc_xprt, xid);
+	if (!req)
+		goto unlock_notfound;
 
 	memcpy(&req->rq_private_buf, &req->rq_rcv_buf, sizeof(struct xdr_buf));
 	/*
@@ -1040,11 +1035,21 @@ static int receive_cb_reply(struct svc_sock *svsk, struct svc_rqst *rqstp)
 	dst = &req->rq_private_buf.head[0];
 	src = &rqstp->rq_arg.head[0];
 	if (dst->iov_len < src->iov_len)
-		return -EAGAIN; /* whatever; just giving up. */
+		goto unlock_eagain; /* whatever; just giving up. */
 	memcpy(dst->iov_base, src->iov_base, src->iov_len);
 	xprt_complete_rqst(req->rq_task, rqstp->rq_arg.len);
 	rqstp->rq_arg.len = 0;
+	spin_unlock_bh(&bc_xprt->transport_lock);
 	return 0;
+unlock_notfound:
+	printk(KERN_NOTICE
+		"%s: Got unrecognized reply: "
+		"calldir 0x%x xpt_bc_xprt %p xid %08x\n",
+		__func__, ntohl(calldir),
+		bc_xprt, ntohl(xid));
+unlock_eagain:
+	spin_unlock_bh(&bc_xprt->transport_lock);
+	return -EAGAIN;
 }
 
 static int copy_pages_to_kvecs(struct kvec *vec, struct page **pages, int len)