lockd: dont return EAGAIN for a permanent error

Fix nlm_fopen() to return NLM_FAILED (or NLM_LCK_DENIED_NOLOCKS) instead
of NLM_LCK_DENIED.  The latter means the lock request failed because of a
conflicting lock (i.e.  a temporary error), which is wrong in this case.

Also fix the client to return ENOLCK instead of EAGAIN if a blocking lock
request returns with NLM_LOCK_DENIED.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: Matthew Wilcox <matthew@wil.cx>
Cc: David Teigland <teigland@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/lockd/clntproc.c

@@ -582,6 +582,14 @@ again:
 	}
 	if (status < 0)
 		goto out_unlock;
+	/*
+	 * EAGAIN doesn't make sense for sleeping locks, and in some
+	 * cases NLM_LCK_DENIED is returned for a permanent error.  So
+	 * turn it into an ENOLCK.
+	 */
+	if (resp->status == nlm_lck_denied && (fl_flags & FL_SLEEP))
+		status = -ENOLCK;
+	else
 		status = nlm_stat_to_errno(resp->status);
 out_unblock:
 	nlmclnt_finish_block(block);

fs/nfsd/lockd.c

@@ -19,6 +19,13 @@
 
 #define NFSDDBG_FACILITY		NFSDDBG_LOCKD
 
+#ifdef CONFIG_LOCKD_V4
+#define nlm_stale_fh	nlm4_stale_fh
+#define nlm_failed	nlm4_failed
+#else
+#define nlm_stale_fh	nlm_lck_denied_nolocks
+#define nlm_failed	nlm_lck_denied_nolocks
+#endif
 /*
  * Note: we hold the dentry use count while the file is open.
  */
@@ -47,12 +54,10 @@ nlm_fopen(struct svc_rqst *rqstp, struct nfs_fh *f, struct file **filp)
 		return 0;
 	case nfserr_dropit:
 		return nlm_drop_reply;
-#ifdef CONFIG_LOCKD_V4
 	case nfserr_stale:
-		return nlm4_stale_fh;
-#endif
+		return nlm_stale_fh;
 	default:
-		return nlm_lck_denied;
+		return nlm_failed;
 	}
 }