auto-start mdmon on --create

[thirdparty/mdadm.git] / Create.c

diff --git a/Create.c b/Create.c
index ee73548ddd541c5b07f1f4ef0dd591d1d8b21e8b..59a41a66aff5a2e6b3b6dcde4d64e0e9b23deda4 100644 (file)
--- a/Create.c
+++ b/Create.c
@@ -71,6 +71,8 @@ int Create(struct supertype *st, char *mddev, int mdfd,
        int rv;
        int bitmap_fd;
        int have_container = 0;
+       int container_fd;
+       int need_mdmon = 0;
        unsigned long long bitmapsize;
        struct mdinfo *sra;
        struct mdinfo info;
@@ -545,6 +547,31 @@ int Create(struct supertype *st, char *mddev, int mdfd,
                        sprintf(ver, "external:/%s/%d",
                                devnum2devname(st->container_dev),
                                st->container_member);
+                       /* When creating a member, we need to be careful
+                        * to negotiate with mdmon properly.
+                        * If it is already running, we cannot write to
+                        * the devices and must ask it to do that part.
+                        * If it isn't running, we write to the devices,
+                        * and then start it.
+                        * We hold an exclusive open on the container
+                        * device to make sure mdmon doesn't exit after
+                        * we checked that it is running.
+                        *
+                        * For now, fail if it is already running.
+                        */
+                       container_fd = open_dev_excl(st->container_dev);
+                       if (container_fd < 0) {
+                               fprintf(stderr, Name ": Cannot get exclusive "
+                                       "open on container - weird.\n");
+                               return 1;
+                       }
+                       if (mdmon_running(st->container_dev)) {
+                               fprintf(stderr, Name ": mdmon already running "
+                                       "for %s - sorry\n",
+                                       devnum2devname(st->container_dev));
+                               return 1;
+                       }
+                       need_mdmon = 1;
                }
                if ((vers % 100) < 2 ||
                    sra == NULL ||
@@ -681,6 +708,7 @@ int Create(struct supertype *st, char *mddev, int mdfd,
                        case 0:
                                sysfs_set_str(sra, NULL, "array_state",
                                              "active");
+                               need_mdmon = 0;
                                break;
                        default:
                                sysfs_set_str(sra, NULL, "array_state",
@@ -698,6 +726,31 @@ int Create(struct supertype *st, char *mddev, int mdfd,
                }
                if (verbose >= 0)
                        fprintf(stderr, Name ": array %s started.\n", mddev);
+               if (st->ss->external == 2) {
+                       if (need_mdmon) {
+                               int dn = st->container_dev;
+                               int i;
+                               switch(fork()) {
+                               case 0:
+                                       /* FIXME yuk. CLOSE_EXEC?? */
+                                       for (i=3; i < 100; i++)
+                                               close(i);
+                                       execl("./mdmon", "mdmon",
+                                             map_dev(dev2major(dn),
+                                                     dev2minor(dn),
+                                                     1), NULL);
+                                       exit(1);
+                               case -1: fprintf(stderr, Name ": cannot fork. "
+                                                "Array remains readonly\n");
+                                       return 1;
+                               default: ; /* parent - good */
+                               }
+                       } else
+                               signal_mdmon(st->container_dev);
+                       /* FIXME wait for mdmon to set array to read-auto */
+                       sleep(1);
+                       close(container_fd);
+               }
        } else {
                fprintf(stderr, Name ": not starting array - not enough devices.\n");
        }