zfs boot: export boot/primary pool and vdev guid all the way to kenv

This is work in progress to for znextboot and it also provides
some convenient infrastructure.

MFC after:	20 days

2 files changed, 20 insertions, 2 deletions

diff --git a/sys/boot/i386/loader/main.c b/sys/boot/i386/loader/main.c
index 73474cf..84ae713 100644
--- a/sys/boot/i386/loader/main.c
+++ b/sys/boot/i386/loader/main.c
@@ -209,6 +209,7 @@ extract_currdev(void)
 {
     struct i386_devdesc		new_currdev;
 #ifdef LOADER_ZFS_SUPPORT
+    char			buf[20];
     struct zfs_boot_args	*zargs;
 #endif
     int				biosdev = -1;
@@ -239,10 +240,17 @@ extract_currdev(void)
 	if ((kargs->bootflags & KARGS_FLAGS_EXTARG) != 0)
 	    zargs = (struct zfs_boot_args *)(kargs + 1);
 
-	if (zargs != NULL && zargs->size >= sizeof(*zargs)) {
+	if (zargs != NULL &&
+	    zargs->size >= offsetof(struct zfs_boot_args, primary_pool)) {
 	    /* sufficient data is provided */
 	    new_currdev.d_kind.zfs.pool_guid = zargs->pool;
 	    new_currdev.d_kind.zfs.root_guid = zargs->root;
+	    if (zargs->size >= sizeof(*zargs) && zargs->primary_vdev != 0) {
+		sprintf(buf, "%llu", zargs->primary_pool);
+		setenv("vfs.zfs.boot.primary_pool", buf, 1);
+		sprintf(buf, "%llu", zargs->primary_vdev);
+		setenv("vfs.zfs.boot.primary_vdev", buf, 1);
+	    }
 	} else {
 	    /* old style zfsboot block */
 	    new_currdev.d_kind.zfs.pool_guid = kargs->zfspool;
diff --git a/sys/boot/i386/zfsboot/zfsboot.c b/sys/boot/i386/zfsboot/zfsboot.c
index 437a97a..928cd71 100644
--- a/sys/boot/i386/zfsboot/zfsboot.c
+++ b/sys/boot/i386/zfsboot/zfsboot.c
@@ -176,6 +176,8 @@ zfs_read(spa_t *spa, const dnode_phys_t *dnode, off_t *offp, void *start, size_t
  * Current ZFS pool
  */
 static spa_t *spa;
+static spa_t *primary_spa;
+static vdev_t *primary_vdev;
 
 /*
  * A wrapper for dskread that doesn't have to worry about whether the
@@ -526,7 +528,7 @@ main(void)
      * first pool we found, if any.
      */
     if (!spa) {
-	spa = STAILQ_FIRST(&zfs_pools);
+	spa = spa_get_primary();
 	if (!spa) {
 	    printf("%s: No ZFS pools located, can't boot\n", BOOTPROG);
 	    for (;;)
@@ -534,6 +536,9 @@ main(void)
 	}
     }
 
+    primary_spa = spa;
+    primary_vdev = spa_get_primary_vdev(spa);
+
     if (zfs_spa_init(spa) != 0 || zfs_mount(spa, 0, &zfsmount) != 0) {
 	printf("%s: failed to mount default pool %s\n",
 	    BOOTPROG, spa->spa_name);
@@ -702,6 +707,11 @@ load(void)
     zfsargs.size = sizeof(zfsargs);
     zfsargs.pool = zfsmount.spa->spa_guid;
     zfsargs.root = zfsmount.rootobj;
+    zfsargs.primary_pool = primary_spa->spa_guid;
+    if (primary_vdev != NULL)
+	zfsargs.primary_vdev = primary_vdev->v_guid;
+    else
+	printf("failed to detect primary vdev\n");
     __exec((caddr_t)addr, RB_BOOTINFO | (opts & RBX_MASK),
 	   bootdev,
 	   KARGS_FLAGS_ZFS | KARGS_FLAGS_EXTARG,