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Fix zhack label repair checksum repair regression on nonzero TXG #17732

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Fix zhack label repair checksum repair regression on nonzero TXG #17732

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2e6a017
Refactor `zhack label repair` and fix `-c` regression on nonzero TXG
buzzingwires Sep 12, 2025
b334d12
Add `typeset`s to `zhack label repair` test scripts
buzzingwires Sep 15, 2025
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134 changes: 78 additions & 56 deletions cmd/zhack.c
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Original file line number Diff line number Diff line change
Expand Up @@ -714,6 +714,23 @@ zhack_repair_read_label(const int fd, vdev_label_t *vl,
return (0);
}

static int
zhack_repair_get_byteswap(const zio_eck_t *vdev_eck, const int l, int *byteswap)
{
if (vdev_eck->zec_magic == ZEC_MAGIC) {
*byteswap = B_FALSE;
} else if (vdev_eck->zec_magic == BSWAP_64((uint64_t)ZEC_MAGIC)) {
*byteswap = B_TRUE;
} else {
(void) fprintf(stderr, "error: label %d: "
"Expected the nvlist checksum magic number but instead got "
"0x%" PRIx64 "\n",
l, vdev_eck->zec_magic);
return (1);
}
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)
Expand All @@ -740,33 +757,10 @@ zhack_repair_calc_cksum(const int byteswap, void *data, const uint64_t offset,
}

static int
zhack_repair_check_label(uberblock_t *ub, const int l, const char **cfg_keys,
const size_t cfg_keys_len, nvlist_t *cfg, nvlist_t *vdev_tree_cfg,
uint64_t *ashift)
zhack_repair_get_ashift(nvlist_t *cfg, const int l, uint64_t *ashift)
{
int err;

if (ub->ub_txg != 0) {
(void) fprintf(stderr,
"error: label %d: UB TXG of 0 expected, but got %"
PRIu64 "\n",
l, ub->ub_txg);
(void) fprintf(stderr, "It would appear the device was not "
"properly removed.\n");
return (1);
}

for (int i = 0; i < cfg_keys_len; i++) {
uint64_t val;
err = nvlist_lookup_uint64(cfg, cfg_keys[i], &val);
if (err) {
(void) fprintf(stderr,
"error: label %d, %d: "
"cannot find nvlist key %s\n",
l, i, cfg_keys[i]);
return (err);
}
}
nvlist_t *vdev_tree_cfg;

err = nvlist_lookup_nvlist(cfg,
ZPOOL_CONFIG_VDEV_TREE, &vdev_tree_cfg);
Expand All @@ -790,7 +784,7 @@ zhack_repair_check_label(uberblock_t *ub, const int l, const char **cfg_keys,
(void) fprintf(stderr,
"error: label %d: nvlist key %s is zero\n",
l, ZPOOL_CONFIG_ASHIFT);
return (err);
return (1);
}

return (0);
Expand All @@ -805,30 +799,35 @@ zhack_repair_undetach(uberblock_t *ub, nvlist_t *cfg, const int l)
*/
if (BP_GET_LOGICAL_BIRTH(&ub->ub_rootbp) != 0) {
const uint64_t txg = BP_GET_LOGICAL_BIRTH(&ub->ub_rootbp);
int err;

ub->ub_txg = txg;

if (nvlist_remove_all(cfg, ZPOOL_CONFIG_CREATE_TXG) != 0) {
err = nvlist_remove_all(cfg, ZPOOL_CONFIG_CREATE_TXG);
if (err) {
(void) fprintf(stderr,
"error: label %d: "
"Failed to remove pool creation TXG\n",
l);
return (1);
return (err);
}

if (nvlist_remove_all(cfg, ZPOOL_CONFIG_POOL_TXG) != 0) {
err = nvlist_remove_all(cfg, ZPOOL_CONFIG_POOL_TXG);
if (err) {
(void) fprintf(stderr,
"error: label %d: Failed to remove pool TXG to "
"be replaced.\n",
l);
return (1);
return (err);
}

if (nvlist_add_uint64(cfg, ZPOOL_CONFIG_POOL_TXG, txg) != 0) {
err = nvlist_add_uint64(cfg, ZPOOL_CONFIG_POOL_TXG, txg);
if (err) {
(void) fprintf(stderr,
"error: label %d: "
"Failed to add pool TXG of %" PRIu64 "\n",
l, txg);
return (1);
return (err);
}
}

Expand Down Expand Up @@ -922,6 +921,7 @@ zhack_repair_test_cksum(const int byteswap, void *vdev_data,
BSWAP_64(ZEC_MAGIC) : ZEC_MAGIC;
const uint64_t actual_magic = vdev_eck->zec_magic;
int err = 0;

if (actual_magic != expected_magic) {
(void) fprintf(stderr, "error: label %d: "
"Expected "
Expand All @@ -943,6 +943,36 @@ zhack_repair_test_cksum(const int byteswap, void *vdev_data,
return (err);
}

static int
zhack_repair_unpack_cfg(vdev_label_t *vl, const int l, nvlist_t **cfg)
{
const char *cfg_keys[] = { ZPOOL_CONFIG_VERSION,
ZPOOL_CONFIG_POOL_STATE, ZPOOL_CONFIG_GUID };
int err;

err = nvlist_unpack(vl->vl_vdev_phys.vp_nvlist,
VDEV_PHYS_SIZE - sizeof (zio_eck_t), cfg, 0);
if (err) {
(void) fprintf(stderr,
"error: cannot unpack nvlist label %d\n", l);
return (err);
}

for (int i = 0; i < ARRAY_SIZE(cfg_keys); i++) {
uint64_t val;
err = nvlist_lookup_uint64(*cfg, cfg_keys[i], &val);
if (err) {
(void) fprintf(stderr,
"error: label %d, %d: "
"cannot find nvlist key %s\n",
l, i, cfg_keys[i]);
return (err);
}
}

return (0);
}

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,
Expand All @@ -956,29 +986,17 @@ zhack_repair_one_label(const zhack_repair_op_t op, const int fd,
(zio_eck_t *)((char *)(vdev_data) + VDEV_PHYS_SIZE) - 1;
const uint64_t vdev_phys_offset =
label_offset + offsetof(vdev_label_t, vl_vdev_phys);
const char *cfg_keys[] = { ZPOOL_CONFIG_VERSION,
ZPOOL_CONFIG_POOL_STATE, ZPOOL_CONFIG_GUID };
nvlist_t *cfg;
nvlist_t *vdev_tree_cfg = NULL;
uint64_t ashift;
int byteswap;

err = zhack_repair_read_label(fd, vl, label_offset, l);
if (err)
return;

if (vdev_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");
err = zhack_repair_get_byteswap(vdev_eck, l, &byteswap);
if (err)
return;
}

byteswap =
(vdev_eck->zec_magic == BSWAP_64((uint64_t)ZEC_MAGIC));

if (byteswap) {
byteswap_uint64_array(&vdev_eck->zec_cksum,
Expand All @@ -994,23 +1012,27 @@ zhack_repair_one_label(const zhack_repair_op_t op, const int fd,
return;
}

err = nvlist_unpack(vl->vl_vdev_phys.vp_nvlist,
VDEV_PHYS_SIZE - sizeof (zio_eck_t), &cfg, 0);
if (err) {
(void) fprintf(stderr,
"error: cannot unpack nvlist label %d\n", l);
return;
}

err = zhack_repair_check_label(ub,
l, cfg_keys, ARRAY_SIZE(cfg_keys), cfg, vdev_tree_cfg, &ashift);
err = zhack_repair_unpack_cfg(vl, l, &cfg);
if (err)
return;

if ((op & ZHACK_REPAIR_OP_UNDETACH) != 0) {
char *buf;
size_t buflen;

if (ub->ub_txg != 0) {
(void) fprintf(stderr,
"error: label %d: UB TXG of 0 expected, but got %"
PRIu64 "\n", l, ub->ub_txg);
(void) fprintf(stderr, "It would appear the device was "
"not properly detached.\n");
return;
}

err = zhack_repair_get_ashift(cfg, l, &ashift);
if (err)
return;

err = zhack_repair_undetach(ub, cfg, l);
if (err)
return;
Expand Down
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