Document why this is necessary.

diff --git a/nbd-client.c b/nbd-client.c
index 9f67da4..9d0ad10 100644 (file)
--- a/nbd-client.c
+++ b/nbd-client.c
@@ -316,6 +316,17 @@ int main(int argc, char *argv[]) {
        if(!nofork) daemon(0,0);
        do {
                if (fork()) {
+                       /* Due to a race, the kernel NBD driver cannot
+                        * call for a reread of the partition table
+                        * in the handling of the NBD_DO_IT ioctl().
+                        * Therefore, this is done in the first open()
+                        * of the device. We therefore make sure that
+                        * the device is opened at least once after the
+                        * connection was made. This has to be done in a
+                        * separate process, since the NBD_DO_IT ioctl()
+                        * does not return until the NBD device has
+                        * disconnected.
+                        */
                        while(check_conn(nbddev, 0)) {
                                sleep(1);
                        }