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

2 files changed, 12 insertions, 5 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