[libmultipath] generic discovery.c:wait_for_file()

clearly state the wait for file (sysfs or device node) logic is needed
only for multipathd, because it races udev upon uevent broadcast.

for multipath(8), which is ran by udev *after* devnode creation,
wait_for_file() just returns "ok".

diff --git a/libmultipath/discovery.c b/libmultipath/discovery.c
index 3558b00..e295eae 100644 (file)
--- a/libmultipath/discovery.c
+++ b/libmultipath/discovery.c
@@ -108,11 +108,16 @@ path_discovery (vector pathvec, struct config * conf, int flag)
        return r;
 }
 
+/*
+ * the daemon can race udev upon path add,
+ * not multipath(8), ran by udev
+ */
+#if DAEMON
 #define WAIT_MAX_SECONDS 5
 #define WAIT_LOOP_PER_SECOND 5
 
 static int
-wait_sysfs_attr (char * filename)
+wait_for_file (char * filename)
 {
        int loop;
        struct stat stats;
@@ -123,10 +128,20 @@ wait_sysfs_attr (char * filename)
                if (stat(filename, &stats) == 0)
                        return 0;
 
+               if (errno != ENOENT)
+                       return 1;
+
                usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
        }
        return 1;
-}      
+}
+#else
+static int
+wait_for_file (char * filename)
+{
+       return 0;
+}
+#endif
                        
 #define declare_sysfs_get_str(fname, fmt) \
 extern int \
@@ -139,7 +154,7 @@ sysfs_get_##fname (char * sysfs_path, char * dev, char * buff, int len) \
        if (safe_sprintf(attr_path, fmt, sysfs_path, dev)) \
                return 1; \
 \
-       if (wait_sysfs_attr(attr_path)) \
+       if (wait_for_file(attr_path)) \
                return 1; \
 \
        if (0 > sysfs_read_attribute_value(attr_path, attr_buff, sizeof(attr_buff))) \
@@ -171,7 +186,7 @@ sysfs_get_##fname (char * sysfs_path, char * dev) \
        if (safe_sprintf(attr_path, fmt, sysfs_path, dev)) \
                return 0; \
 \
-       if (wait_sysfs_attr(attr_path)) \
+       if (wait_for_file(attr_path)) \
                return 0; \
 \
        if (0 > sysfs_read_attribute_value(attr_path, attr_buff, sizeof(attr_buff))) \
@@ -194,30 +209,18 @@ 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)) {
                condlog(0, "devpath too small");
                return -1;
        }
 
-       loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
-       
-       while (--loop) {
-               fd = open(devpath, mode);
-
-               if (fd <= 0 && errno != ENOENT) {
-                       condlog(3, "open error (%s)\n", strerror(errno));
-                       return fd;
-               }
-               if (fd > 0)
-                       return fd;
-
-               usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
+       if (wait_for_file(devpath)) {
+               condlog(3, "failed to open %s", devpath);
+               return -1;
        }
-       condlog(0, "failed to open %s", devpath);
-       return -1;
+
+       return open(devpath, mode);
 }
 
 int