nfs4: Add support for O_NONBLOCK mode

src/add-ons/kernel/file_systems/nfs4/Inode.cpp

@@ -1285,14 +1285,20 @@ Inode::_HandleErrors(uint32 nfs4Error, RPC::Server* serv,
 
 		// server needs more time, we need to wait
 		case NFS4ERR_DELAY:
-			snooze_etc(5 * 1000000, B_SYSTEM_TIMEBASE, B_RELATIVE_TIMEOUT);
-			return true;
+			if (cookie == NULL || (cookie->fMode & O_NONBLOCK) == 0) {
+				snooze_etc(5 * 1000000, B_SYSTEM_TIMEBASE, B_RELATIVE_TIMEOUT);
+				return true;
+			} else
+				return false;
 
 		// server is in grace period, we need to wait
 		case NFS4ERR_GRACE:
-			snooze_etc(fFilesystem->NFSServer()->LeaseTime() / 3,
-				B_SYSTEM_TIMEBASE, B_RELATIVE_TIMEOUT);
-			return true;
+			if (cookie == NULL || (cookie->fMode & O_NONBLOCK) == 0) {
+				snooze_etc(fFilesystem->NFSServer()->LeaseTime() / 3,
+					B_SYSTEM_TIMEBASE, B_RELATIVE_TIMEOUT);
+				return true;
+			} else
+				return false;
 
 		// server has rebooted, reclaim share and try again
 		case NFS4ERR_STALE_CLIENTID:

src/add-ons/kernel/file_systems/nfs4/ReplyInterpreter.cpp

@@ -674,6 +674,10 @@ ReplyInterpreter::_NFS4ErrorToHaiku(uint32 x)
 		case NFS4ERR_INVAL:		return B_BAD_VALUE;
 		case NFS4ERR_FBIG:		return B_FILE_TOO_LARGE;
 		// ...
+		case NFS4ERR_DELAY:
+		case NFS4ERR_GRACE:
+								return B_WOULD_BLOCK;
+		// ...
 		default:				return B_ERROR;
 	}
 }