[libmultipath] opennode() must wait for udev to create the devnode

Indeed, now that the daemon races udev in receiving uevents, it can
try opening the devnode before udev is given a chance to create it.

Do that the same way we wait for sysfs files to appear.

diff --git a/libmultipath/discovery.c b/libmultipath/discovery.c
index 41ecc10..6b69a81 100644 (file)
--- a/libmultipath/discovery.c
+++ b/libmultipath/discovery.c
@@ -171,22 +171,33 @@ sysfs_get_##fname (char * sysfs_path, char * dev) \
 
 declare_sysfs_get_val(size, "%s/block/%s/size");
 
+/*
+ * udev might be slow creating node files : wait
+ */
 static int
 opennode (char * dev, int mode)
 {
        char devpath[FILE_NAME_SIZE];
        int fd;
+       int loop;
 
        if (safe_sprintf(devpath, "%s/%s", conf->udev_dir, dev)) {
                fprintf(stderr, "devpath too small\n");
                return -1;
        }
-       fd = open(devpath, mode);
 
-       if (fd <= 0)
-               condlog(0, "open(%s) failed", devpath);
+       loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
        
-       return fd;
+       while (--loop) {
+               fd = open(devpath, mode);
+
+               if (fd > 0)
+                       return fd;
+
+               usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
+       }
+       condlog(0, "failed to open %s", devpath);
+       return -1;
 }
 
 #if 0