loader: zfs should support bootonce an nextboot

bootonce feature is temporary, one time boot, activated by
"bectl activate -t BE", "bectl activate -T BE" will reset the bootonce flag.

By default, the bootonce setting is reset on attempt to boot and the next
boot will use previously active BE.

By setting zfs_bootonce_activate="YES" in rc.conf, the bootonce BE will
be set permanently active.

bootonce dataset name is recorded in boot pool labels, bootenv area.

in case of nextboot, the nextboot_enable boolean variable is recorded in
freebsd:nvstore nvlist, also stored in boot pool label bootenv area.
On boot, the loader will process /boot/nextboot.conf if nextboot_enable
is "YES", and will set nextboot_enable to "NO", preventing /boot/nextboot.conf
processing on next boot.

bootonce and nextboot features are usable in both UEFI and BIOS boot.

To use bootonce/nextboot features, the boot loader needs to be updated on disk;
if loader.efi is stored on ESP, then ESP needs to be updated and
for BIOS boot, stage2 (zfsboot or gptzfsboot) needs to be updated
(gpart or other tools).

At this time, only lua loader is updated.

Sponsored by:	Netflix, Klara Inc.
Differential Revision:	https://reviews.freebsd.org/D25512

1 files changed, 21 insertions, 20 deletions

diff --git a/sys/cddl/boot/zfs/zfsimpl.h b/sys/cddl/boot/zfs/zfsimpl.h
index 6a6331450e8b..a005f892508f 100644
--- a/sys/cddl/boot/zfs/zfsimpl.h
+++ b/sys/cddl/boot/zfs/zfsimpl.h
@@ -527,20 +527,20 @@ typedef struct vdev_phys {
 } vdev_phys_t;
 
 typedef enum vbe_vers {
- 	/* The bootenv file is stored as ascii text in the envblock */
- 	VB_RAW = 0,
-
-  	/*
- 	 * The bootenv file is converted to an nvlist and then packed into the
- 	 * envblock.
- 	 */
- 	VB_NVLIST = 1
+	/* The bootenv file is stored as ascii text in the envblock */
+	VB_RAW = 0,
+
+	/*
+	 * The bootenv file is converted to an nvlist and then packed into the
+	 * envblock.
+	 */
+	VB_NVLIST = 1
 } vbe_vers_t;
 
 typedef struct vdev_boot_envblock {
- 	uint64_t	vbe_version;
- 	char		vbe_bootenv[VDEV_PAD_SIZE - sizeof (uint64_t) -
- 			sizeof (zio_eck_t)];
+	uint64_t	vbe_version;
+	char		vbe_bootenv[VDEV_PAD_SIZE - sizeof (uint64_t) -
+			sizeof (zio_eck_t)];
  	zio_eck_t	vbe_zbt;
 } vdev_boot_envblock_t;
 
@@ -1663,10 +1663,9 @@ typedef struct znode_phys {
  */
 struct vdev;
 struct spa;
-typedef int vdev_phys_read_t(struct vdev *vdev, void *priv,
-    off_t offset, void *buf, size_t bytes);
-typedef int vdev_read_t(struct vdev *vdev, const blkptr_t *bp,
-    void *buf, off_t offset, size_t bytes);
+typedef int vdev_phys_read_t(struct vdev *, void *, off_t, void *, size_t);
+typedef int vdev_phys_write_t(struct vdev *, off_t, void *, size_t);
+typedef int vdev_read_t(struct vdev *, const blkptr_t *, void *, off_t, size_t);
 
 typedef STAILQ_HEAD(vdev_list, vdev) vdev_list_t;
 
@@ -1794,8 +1793,9 @@ typedef struct vdev {
 	size_t		v_nchildren;	/* # children */
 	vdev_state_t	v_state;	/* current state */
 	vdev_phys_read_t *v_phys_read;	/* read from raw leaf vdev */
+	vdev_phys_write_t *v_phys_write; /* write to raw leaf vdev */
 	vdev_read_t	*v_read;	/* read from vdev */
-	void		*v_read_priv;	/* private data for read function */
+	void		*v_priv;	/* data for read/write function */
 	boolean_t	v_islog;
 	struct spa	*v_spa;		/* link to spa */
 	/*
@@ -1822,10 +1822,11 @@ typedef struct spa {
 	void		*spa_cksum_tmpls[ZIO_CHECKSUM_FUNCTIONS];
 	boolean_t	spa_with_log;	/* this pool has log */
 
-	struct uberblock spa_uberblock_master;  /* best uberblock so far */
-	objset_phys_t    spa_mos_master;        /* MOS for this pool */
-	struct uberblock spa_uberblock_checkpoint;      /* checkpoint uberblock */
-	objset_phys_t    spa_mos_checkpoint;    /* Checkpoint MOS */
+	struct uberblock spa_uberblock_master;	/* best uberblock so far */
+	objset_phys_t	spa_mos_master;		/* MOS for this pool */
+	struct uberblock spa_uberblock_checkpoint; /* checkpoint uberblock */
+	objset_phys_t	spa_mos_checkpoint;	/* Checkpoint MOS */
+	void		*spa_bootenv;		/* bootenv from pool label */
 } spa_t;
 
 /* IO related arguments. */