Implement new label format for large disks

This patch contains the logic for a new larger label format. This format
is intended to support disks with large sector sizes. By using a larger
label we can store more uberblocks and other critical pool metadata. We
can also use the extra space to enable new features in ZFS going
forwards. This initial commit does not add new capabilities, but
provides the framework for them going forwards.

Signed-off-by: Paul Dagnelie <paul.dagnelie@klarasystems.com>
Sponsored-by: Wasabi, Inc.
Sponsored-by: Klara, Inc.

Author: pcd1193182

cmd/zdb/zdb.c

@@ -496,11 +496,11 @@ zhack_do_feature(int argc, char **argv)
 	return (0);
 }
 
-#define	ASHIFT_UBERBLOCK_SHIFT(ashift)	\
+#define	ASHIFT_UBERBLOCK_SHIFT(ashift, new)	\
 	MIN(MAX(ashift, UBERBLOCK_SHIFT), \
-	MAX_UBERBLOCK_SHIFT)
-#define	ASHIFT_UBERBLOCK_SIZE(ashift) \
-	(1ULL << ASHIFT_UBERBLOCK_SHIFT(ashift))
+	MAX_UBERBLOCK_SHIFT(new))
+#define	ASHIFT_UBERBLOCK_SIZE(ashift, new) \
+	(1ULL << ASHIFT_UBERBLOCK_SHIFT(ashift, new))
 
 #define	REPAIR_LABEL_STATUS_CKSUM (1 << 0)
 #define	REPAIR_LABEL_STATUS_UB    (1 << 1)
@@ -525,6 +525,26 @@ zhack_repair_read_label(const int fd, vdev_label_t *vl,
 	return (0);
 }
 
+static int
+zhack_repair_read(const int fd, uint8_t *buf, size_t buflen,
+    const uint64_t offset, const int l)
+{
+	const int err = pread64(fd, buf, buflen, offset);
+
+	if (err == -1) {
+		(void) fprintf(stderr,
+		    "error: cannot read buffer at %lu for label %d: %s\n",
+		    offset, l, strerror(errno));
+		return (err);
+	} else if (err != buflen) {
+		(void) fprintf(stderr,
+		    "error: bad read size at %lu for label %d \n", offset, l);
+		return (err);
+	}
+
+	return (0);
+}
+
 static void
 zhack_repair_calc_cksum(const int byteswap, void *data, const uint64_t offset,
     const uint64_t abdsize, zio_eck_t *eck, zio_cksum_t *cksum)
@@ -687,7 +707,7 @@ zhack_repair_write_uberblock(vdev_label_t *vl, const int l,
 	    (char *)vl + offsetof(vdev_label_t, vl_uberblock);
 	zio_eck_t *ub_eck =
 	    (zio_eck_t *)
-	    ((char *)(ub_data) + (ASHIFT_UBERBLOCK_SIZE(ashift))) - 1;
+	    ((char *)(ub_data) + (ASHIFT_UBERBLOCK_SIZE(ashift, B_FALSE))) - 1;
 
 	if (ub_eck->zec_magic != 0) {
 		(void) fprintf(stderr,
@@ -706,10 +726,39 @@ zhack_repair_write_uberblock(vdev_label_t *vl, const int l,
 	if (zhack_repair_write_label(l, fd, byteswap,
 	    ub_data, ub_eck,
 	    label_offset + offsetof(vdev_label_t, vl_uberblock),
-	    ASHIFT_UBERBLOCK_SIZE(ashift)))
+	    ASHIFT_UBERBLOCK_SIZE(ashift, B_FALSE)))
 			labels_repaired[l] |= REPAIR_LABEL_STATUS_UB;
 }
 
+static void
+zhack_repair_write_uberblock_new(void *ub_data, const int l,
+    const uint64_t ashift, const int fd, const int byteswap,
+    const uint64_t label_offset, uint32_t *labels_repaired)
+{
+	zio_eck_t *ub_eck =
+	    (zio_eck_t *)
+	    ((char *)(ub_data) + (ASHIFT_UBERBLOCK_SIZE(ashift, B_FALSE))) - 1;
+
+	if (ub_eck->zec_magic != 0) {
+		(void) fprintf(stderr,
+		    "error: label %d: "
+		    "Expected Uberblock checksum magic number to "
+		    "be 0, but got %" PRIu64 "\n",
+		    l, ub_eck->zec_magic);
+		(void) fprintf(stderr, "It would appear there's already "
+		    "a checksum for the uberblock.\n");
+		return;
+	}
+
+
+	ub_eck->zec_magic = byteswap ? BSWAP_64(ZEC_MAGIC) : ZEC_MAGIC;
+
+	if (zhack_repair_write_label(l, fd, byteswap,
+	    ub_data, ub_eck, label_offset + VDEV_LARGE_UBERBLOCK_RING,
+	    ASHIFT_UBERBLOCK_SIZE(ashift, B_TRUE)))
+		labels_repaired[l] |= REPAIR_LABEL_STATUS_UB;
+}
+
 static void
 zhack_repair_print_cksum(FILE *stream, const zio_cksum_t *cksum)
 {
@@ -723,12 +772,13 @@ zhack_repair_print_cksum(FILE *stream, const zio_cksum_t *cksum)
 
 static int
 zhack_repair_test_cksum(const int byteswap, void *vdev_data,
-    zio_eck_t *vdev_eck, const uint64_t vdev_phys_offset, const int l)
+    const uint64_t size, zio_eck_t *vdev_eck, const uint64_t vdev_phys_offset,
+    const int l)
 {
 	const zio_cksum_t expected_cksum = vdev_eck->zec_cksum;
 	zio_cksum_t actual_cksum;
 	zhack_repair_calc_cksum(byteswap, vdev_data, vdev_phys_offset,
-	    VDEV_PHYS_SIZE, vdev_eck, &actual_cksum);
+	    size, vdev_eck, &actual_cksum);
 	const uint64_t expected_magic = byteswap ?
 	    BSWAP_64(ZEC_MAGIC) : ZEC_MAGIC;
 	const uint64_t actual_magic = vdev_eck->zec_magic;
@@ -756,15 +806,17 @@ zhack_repair_test_cksum(const int byteswap, void *vdev_data,
 
 static void
 zhack_repair_one_label(const zhack_repair_op_t op, const int fd,
-    vdev_label_t *vl, const uint64_t label_offset, const int l,
-    uint32_t *labels_repaired)
+    vdev_label_t *vl, const uint64_t filesize, const int l,
+    uint32_t *labels_repaired, boolean_t *large_label)
 {
 	ssize_t err;
 	uberblock_t *ub = (uberblock_t *)vl->vl_uberblock;
 	void *vdev_data =
 	    (char *)vl + offsetof(vdev_label_t, vl_vdev_phys);
 	zio_eck_t *vdev_eck =
 	    (zio_eck_t *)((char *)(vdev_data) + VDEV_PHYS_SIZE) - 1;
+	const uint64_t label_offset = vdev_label_offset(filesize, l, 0,
+	    B_FALSE);
 	const uint64_t vdev_phys_offset =
 	    label_offset + offsetof(vdev_label_t, vl_vdev_phys);
 	const char *cfg_keys[] = { ZPOOL_CONFIG_VERSION,
@@ -798,8 +850,8 @@ zhack_repair_one_label(const zhack_repair_op_t op, const int fd,
 	}
 
 	if ((op & ZHACK_REPAIR_OP_CKSUM) == 0 &&
-	    zhack_repair_test_cksum(byteswap, vdev_data, vdev_eck,
-	    vdev_phys_offset, l) != 0) {
+	    zhack_repair_test_cksum(byteswap, vdev_data, VDEV_PHYS_SIZE,
+	    vdev_eck, vdev_phys_offset, l) != 0) {
 		(void) fprintf(stderr, "It would appear checksums are "
 		    "corrupted. Try zhack repair label -c <device>\n");
 		return;
@@ -812,6 +864,8 @@ zhack_repair_one_label(const zhack_repair_op_t op, const int fd,
 		    "error: cannot unpack nvlist label %d\n", l);
 		return;
 	}
+	(void) nvlist_lookup_boolean_value(cfg, ZPOOL_CONFIG_LARGE_LABEL,
+	    large_label);
 
 	err = zhack_repair_check_label(ub,
 	    l, cfg_keys, ARRAY_SIZE(cfg_keys), cfg, vdev_tree_cfg, &ashift);
@@ -836,13 +890,212 @@ zhack_repair_one_label(const zhack_repair_op_t op, const int fd,
 
 		zhack_repair_write_uberblock(vl,
 		    l, ashift, fd, byteswap, label_offset, labels_repaired);
+		if (large_label) {
+			zhack_repair_write_uberblock_new(ub, l, ashift,
+			    fd, byteswap, vdev_label_offset(filesize, l, 0,
+			    B_TRUE), labels_repaired);
+		}
 	}
 
 	if (zhack_repair_write_label(l, fd, byteswap, vdev_data, vdev_eck,
 	    vdev_phys_offset, VDEV_PHYS_SIZE))
-			labels_repaired[l] |= REPAIR_LABEL_STATUS_CKSUM;
+		labels_repaired[l] |= REPAIR_LABEL_STATUS_CKSUM;
+
+	fsync(fd);
+}
+
+static void
+zhack_repair_one_label_large(const zhack_repair_op_t op, const int fd,
+    const uint64_t label_offset, const int l, uint32_t *labels_repaired)
+{
+	ssize_t err;
+	void *toc_data = NULL, *bootenv = NULL, *vdev_config = NULL;
+	void *spa_config = NULL, *ub = NULL;
+	/*
+	 * Note that currently, this can't handle disks with larger than 8k
+	 * sector sizes. That needs to be fixed eventually.
+	 */
+	toc_data = malloc(VDEV_TOC_SIZE);
+	err = zhack_repair_read(fd, toc_data, VDEV_TOC_SIZE, label_offset, l);
+	if (err)
+		goto out;
+
+	zio_eck_t *toc_eck = (zio_eck_t *)(toc_data + VDEV_TOC_SIZE) - 1;
+	if (toc_eck->zec_magic == 0) {
+		(void) fprintf(stderr, "error: label %d: "
+		    "Expected the nvlist checksum magic number to not be zero"
+		    "\n",
+		    l);
+		(void) fprintf(stderr, "There should already be a checksum "
+		    "for the label.\n");
+		goto out;
+	}
+
+	int byteswap =
+	    (toc_eck->zec_magic == BSWAP_64((uint64_t)ZEC_MAGIC));
+
+	if (byteswap) {
+		byteswap_uint64_array(&toc_eck->zec_cksum,
+		    sizeof (zio_cksum_t));
+		toc_eck->zec_magic = BSWAP_64(toc_eck->zec_magic);
+	}
+	if ((op & ZHACK_REPAIR_OP_CKSUM) == 0 &&
+	    zhack_repair_test_cksum(byteswap, toc_data, VDEV_TOC_SIZE,
+	    toc_eck, label_offset, l) != 0) {
+		(void) fprintf(stderr, "It would appear checksums are "
+		    "corrupted. Try zhack repair label -c <device>\n");
+		goto out;
+	}
+
+	nvlist_t *toc;
+	err = nvlist_unpack(toc_data, VDEV_TOC_SIZE, &toc, 0);
+	if (err) {
+		(void) fprintf(stderr,
+		    "error: cannot unpack nvlist TOC %d\n", l);
+		goto out;
+	}
+
+	uint32_t bootenv_size, vc_size, sc_size;
+	if ((err = nvlist_lookup_uint32(toc, VDEV_TOC_BOOT_REGION,
+	    &bootenv_size)) || (err = nvlist_lookup_uint32(toc,
+	    VDEV_TOC_VDEV_CONFIG, &vc_size)) || (err = nvlist_lookup_uint32(toc,
+	    VDEV_TOC_POOL_CONFIG, &sc_size))) {
+		(void) fprintf(stderr,
+		    "error: TOC missing core fields %d\n", l);
+		goto out;
+	}
+	bootenv = malloc(bootenv_size);
+	zio_eck_t *bootenv_eck = (zio_eck_t *)(bootenv + bootenv_size) - 1;
+	vdev_config = malloc(vc_size);
+	zio_eck_t *vc_eck = (zio_eck_t *)(vdev_config + vc_size) - 1;
+	spa_config = malloc(sc_size);
+	zio_eck_t *sc_eck = (zio_eck_t *)(spa_config + sc_size) - 1;
+
+	uint64_t offset = label_offset + VDEV_TOC_SIZE;
+	if (bootenv_size != 0) {
+		if ((err = zhack_repair_read(fd, bootenv,
+		    bootenv_size, offset, l)))
+			goto out;
+		if (byteswap) {
+			byteswap_uint64_array(&bootenv_eck->zec_cksum,
+			    sizeof (zio_cksum_t));
+			bootenv_eck->zec_magic =
+			    BSWAP_64(bootenv_eck->zec_magic);
+		}
+		if ((op & ZHACK_REPAIR_OP_CKSUM) == 0 &&
+		    zhack_repair_test_cksum(byteswap, bootenv, bootenv_size,
+		    bootenv_eck, offset, l) != 0) {
+			(void) fprintf(stderr, "It would appear checksums are "
+			    "corrupted. Try zhack repair label -c <device>\n");
+			goto out;
+		}
+	}
+
+	offset += bootenv_size;
+	if ((err = zhack_repair_read(fd, vdev_config, vc_size, offset, l)))
+		goto out;
+
+	if (byteswap) {
+		byteswap_uint64_array(&sc_eck->zec_cksum,
+		    sizeof (zio_cksum_t));
+		vc_eck->zec_magic = BSWAP_64(vc_eck->zec_magic);
+	}
+	if ((op & ZHACK_REPAIR_OP_CKSUM) == 0 &&
+	    zhack_repair_test_cksum(byteswap, vdev_config, vc_size,
+	    vc_eck, offset, l) != 0) {
+		(void) fprintf(stderr, "It would appear checksums are "
+		    "corrupted. Try zhack repair label -c <device>\n");
+		goto out;
+	}
+	offset += vc_size;
+	if ((err = zhack_repair_read(fd, spa_config, sc_size, offset, l)))
+		goto out;
+
+	if (byteswap) {
+		byteswap_uint64_array(&sc_eck->zec_cksum,
+		    sizeof (zio_cksum_t));
+		vc_eck->zec_magic = BSWAP_64(sc_eck->zec_magic);
+	}
+	if ((op & ZHACK_REPAIR_OP_CKSUM) == 0 &&
+	    zhack_repair_test_cksum(byteswap, spa_config, sc_size,
+	    sc_eck, offset, l) != 0) {
+		(void) fprintf(stderr, "It would appear checksums are "
+		    "corrupted. Try zhack repair label -c <device>\n");
+		goto out;
+	}
+
+	nvlist_t *cfg;
+	err = nvlist_unpack(vdev_config, vc_size - sizeof (zio_eck_t), &cfg, 0);
+	if (err) {
+		(void) fprintf(stderr,
+		    "error: cannot unpack nvlist label %d\n", l);
+		return;
+	}
+
+	ub = malloc(UBERBLOCK_SHIFT);
+	err = zhack_repair_read(fd, ub, UBERBLOCK_SHIFT,
+	    label_offset + VDEV_LARGE_UBERBLOCK_RING, l);
+	if (err)
+		goto out;
+
+	const char *cfg_keys[] = { ZPOOL_CONFIG_VERSION,
+	    ZPOOL_CONFIG_POOL_STATE, ZPOOL_CONFIG_GUID };
+	nvlist_t *vdev_tree_cfg = NULL;
+	uint64_t ashift;
+	err = zhack_repair_check_label(ub, l, cfg_keys, ARRAY_SIZE(cfg_keys),
+	    cfg, vdev_tree_cfg, &ashift);
+	if (err)
+		return;
+
+	if ((op & ZHACK_REPAIR_OP_UNDETACH) != 0) {
+		char *buf;
+		size_t buflen;
+
+		err = zhack_repair_undetach(ub, cfg, l);
+		if (err)
+			return;
+
+		buf = vdev_config;
+		buflen = vc_size - sizeof (zio_eck_t);
+		if (nvlist_pack(cfg, &buf, &buflen, NV_ENCODE_XDR, 0) != 0) {
+			(void) fprintf(stderr,
+			    "error: label %d: Failed to pack nvlist\n", l);
+			return;
+		}
+
+		zhack_repair_write_uberblock_new(ub, l, ashift, fd, byteswap,
+		    label_offset, labels_repaired);
+	}
+
+	offset = label_offset;
+	if (zhack_repair_write_label(l, fd, byteswap, toc_data, toc_eck,
+	    offset, VDEV_TOC_SIZE))
+		labels_repaired[l] |= REPAIR_LABEL_STATUS_CKSUM;
+	offset += VDEV_TOC_SIZE;
+	if (zhack_repair_write_label(l, fd, byteswap, bootenv, bootenv_eck,
+	    offset, bootenv_size))
+		labels_repaired[l] |= REPAIR_LABEL_STATUS_CKSUM;
+	offset += bootenv_size;
+	if (zhack_repair_write_label(l, fd, byteswap, vdev_config, vc_eck,
+	    offset, vc_size))
+		labels_repaired[l] |= REPAIR_LABEL_STATUS_CKSUM;
+	offset += vc_size;
+	if (zhack_repair_write_label(l, fd, byteswap, spa_config, sc_eck,
+	    offset, sc_size))
+		labels_repaired[l] |= REPAIR_LABEL_STATUS_CKSUM;
 
 	fsync(fd);
+out:
+	if (toc_data)
+		free(toc_data);
+	if (bootenv)
+		free(bootenv);
+	if (vdev_config)
+		free(vdev_config);
+	if (spa_config)
+		free(spa_config);
+	if (ub)
+		free(ub);
 }
 
 static const char *
@@ -885,9 +1138,18 @@ zhack_label_repair(const zhack_repair_op_t op, const int argc, char **argv)
 		filesize =
 		    (filesize / sizeof (vdev_label_t)) * sizeof (vdev_label_t);
 
+	boolean_t large_label = B_FALSE;
 	for (int l = 0; l < VDEV_LABELS; l++) {
 		zhack_repair_one_label(op, fd, &labels[l],
-		    vdev_label_offset(filesize, l, 0), l, labels_repaired);
+		    filesize, l, labels_repaired, &large_label);
+		if (large_label)
+			break;
+	}
+	if (large_label) {
+		for (int l = 0; l < VDEV_LABELS; l++) {
+			zhack_repair_one_label_large(op, fd,
+			    filesize, l, labels_repaired);
+		}
 	}
 
 	close(fd);