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

3 files changed, 28 insertions, 16 deletions

diff --git a/fs/nfsd/nfs4callback.c b/fs/nfsd/nfs4callback.c
index ed2b1151b171..7cbdf1b2e4ab 100644
--- a/fs/nfsd/nfs4callback.c
+++ b/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;
 }
diff --git a/fs/nfsd/nfsd.h b/fs/nfsd/nfsd.h
index 747f3b95bd11..33a46a8dfaf7 100644
--- a/fs/nfsd/nfsd.h
+++ b/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
diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c
index 3f959c681885..f9c052d508f0 100644
--- a/net/sunrpc/svcsock.c
+++ b/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)