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zdb -L should skip leak detection altogether

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Currently the point of -L option in zdb is to  disable leak
tracing and the loading of space maps because they are expensive,
yet still do leak detection in terms of space. Unfortunately,
there is a scenario where this is a lie. If we are using zdb -L
on a pool where a vdev is being removed, zdb_claim_removing()
will open the metaslab space maps of that device.

This patch makes it so zdb -L skips leak detection altogether
and ensures that no space maps are loaded.

Reviewed-by: Matt Ahrens <mahrens@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Serapheim Dimitropoulos <serapheim@delphix.com>
Closes #8335
This commit is contained in:
Serapheim Dimitropoulos 2019-01-30 09:54:27 -08:00 committed by Brian Behlendorf
parent 466f55334a
commit 21e7cf5da8
2 changed files with 136 additions and 123 deletions
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255
cmd/zdb/zdb.c
View File

@ -799,12 +799,15 @@ dump_spacemap(objset_t *os, space_map_t *sm)
(void) printf(" smp_alloc = 0x%llx\n",
(longlong_t)sm->sm_phys->smp_alloc);
if (dump_opt['d'] < 6 && dump_opt['m'] < 4)
return;
/*
* Print out the freelist entries in both encoded and decoded form.
*/
uint8_t mapshift = sm->sm_shift;
int64_t alloc = 0;
uint64_t word;
uint64_t word, entry_id = 0;
for (uint64_t offset = 0; offset < space_map_length(sm);
offset += sizeof (word)) {
@ -812,11 +815,12 @@ dump_spacemap(objset_t *os, space_map_t *sm)
sizeof (word), &word, DMU_READ_PREFETCH));
if (sm_entry_is_debug(word)) {
(void) printf("\t [%6llu] %s: txg %llu, pass %llu\n",
(u_longlong_t)(offset / sizeof (word)),
(void) printf("\t [%6llu] %s: txg %llu pass %llu\n",
(u_longlong_t)entry_id,
ddata[SM_DEBUG_ACTION_DECODE(word)],
(u_longlong_t)SM_DEBUG_TXG_DECODE(word),
(u_longlong_t)SM_DEBUG_SYNCPASS_DECODE(word));
entry_id++;
continue;
}
@ -854,7 +858,7 @@ dump_spacemap(objset_t *os, space_map_t *sm)
(void) printf("\t [%6llu] %c range:"
" %010llx-%010llx size: %06llx vdev: %06llu words: %u\n",
(u_longlong_t)(offset / sizeof (word)),
(u_longlong_t)entry_id,
entry_type, (u_longlong_t)entry_off,
(u_longlong_t)(entry_off + entry_run),
(u_longlong_t)entry_run,
@ -864,6 +868,7 @@ dump_spacemap(objset_t *os, space_map_t *sm)
alloc += entry_run;
else
alloc -= entry_run;
entry_id++;
}
if ((uint64_t)alloc != space_map_allocated(sm)) {
(void) printf("space_map_object alloc (%lld) INCONSISTENT "
@ -929,11 +934,8 @@ dump_metaslab(metaslab_t *msp)
SPACE_MAP_HISTOGRAM_SIZE, sm->sm_shift);
}
if (dump_opt['d'] > 5 || dump_opt['m'] > 3) {
ASSERT(msp->ms_size == (1ULL << vd->vdev_ms_shift));
dump_spacemap(spa->spa_meta_objset, msp->ms_sm);
}
ASSERT(msp->ms_size == (1ULL << vd->vdev_ms_shift));
dump_spacemap(spa->spa_meta_objset, msp->ms_sm);
}
static void
@ -3599,6 +3601,9 @@ claim_segment_cb(void *arg, uint64_t offset, uint64_t size)
static void
zdb_claim_removing(spa_t *spa, zdb_cb_t *zcb)
{
if (dump_opt['L'])
return;
if (spa->spa_vdev_removal == NULL)
return;
@ -3708,6 +3713,8 @@ zdb_ddt_leak_init(spa_t *spa, zdb_cb_t *zcb)
int error;
int p;
ASSERT(!dump_opt['L']);
bzero(&ddb, sizeof (ddb));
while ((error = ddt_walk(spa, &ddb, &dde)) == 0) {
blkptr_t blk;
@ -3731,12 +3738,10 @@ zdb_ddt_leak_init(spa_t *spa, zdb_cb_t *zcb)
zcb->zcb_dedup_blocks++;
}
}
if (!dump_opt['L']) {
ddt_t *ddt = spa->spa_ddt[ddb.ddb_checksum];
ddt_enter(ddt);
VERIFY(ddt_lookup(ddt, &blk, B_TRUE) != NULL);
ddt_exit(ddt);
}
ddt_t *ddt = spa->spa_ddt[ddb.ddb_checksum];
ddt_enter(ddt);
VERIFY(ddt_lookup(ddt, &blk, B_TRUE) != NULL);
ddt_exit(ddt);
}
ASSERT(error == ENOENT);
@ -3840,6 +3845,8 @@ zdb_leak_init_vdev_exclude_checkpoint(vdev_t *vd, zdb_cb_t *zcb)
static void
zdb_leak_init_exclude_checkpoint(spa_t *spa, zdb_cb_t *zcb)
{
ASSERT(!dump_opt['L']);
vdev_t *rvd = spa->spa_root_vdev;
for (uint64_t c = 0; c < rvd->vdev_children; c++) {
ASSERT3U(c, ==, rvd->vdev_child[c]->vdev_id);
@ -3936,6 +3943,8 @@ load_indirect_ms_allocatable_tree(vdev_t *vd, metaslab_t *msp,
static void
zdb_leak_init_prepare_indirect_vdevs(spa_t *spa, zdb_cb_t *zcb)
{
ASSERT(!dump_opt['L']);
vdev_t *rvd = spa->spa_root_vdev;
for (uint64_t c = 0; c < rvd->vdev_children; c++) {
vdev_t *vd = rvd->vdev_child[c];
@ -3982,67 +3991,63 @@ zdb_leak_init(spa_t *spa, zdb_cb_t *zcb)
{
zcb->zcb_spa = spa;
if (!dump_opt['L']) {
dsl_pool_t *dp = spa->spa_dsl_pool;
vdev_t *rvd = spa->spa_root_vdev;
if (dump_opt['L'])
return;
/*
* We are going to be changing the meaning of the metaslab's
* ms_allocatable. Ensure that the allocator doesn't try to
* use the tree.
*/
spa->spa_normal_class->mc_ops = &zdb_metaslab_ops;
spa->spa_log_class->mc_ops = &zdb_metaslab_ops;
dsl_pool_t *dp = spa->spa_dsl_pool;
vdev_t *rvd = spa->spa_root_vdev;
zcb->zcb_vd_obsolete_counts =
umem_zalloc(rvd->vdev_children * sizeof (uint32_t *),
UMEM_NOFAIL);
/*
* We are going to be changing the meaning of the metaslab's
* ms_allocatable. Ensure that the allocator doesn't try to
* use the tree.
*/
spa->spa_normal_class->mc_ops = &zdb_metaslab_ops;
spa->spa_log_class->mc_ops = &zdb_metaslab_ops;
/*
* For leak detection, we overload the ms_allocatable trees
* to contain allocated segments instead of free segments.
* As a result, we can't use the normal metaslab_load/unload
* interfaces.
*/
zdb_leak_init_prepare_indirect_vdevs(spa, zcb);
load_concrete_ms_allocatable_trees(spa, SM_ALLOC);
zcb->zcb_vd_obsolete_counts =
umem_zalloc(rvd->vdev_children * sizeof (uint32_t *),
UMEM_NOFAIL);
/*
* On load_concrete_ms_allocatable_trees() we loaded all the
* allocated entries from the ms_sm to the ms_allocatable for
* each metaslab. If the pool has a checkpoint or is in the
* middle of discarding a checkpoint, some of these blocks
* may have been freed but their ms_sm may not have been
* updated because they are referenced by the checkpoint. In
* order to avoid false-positives during leak-detection, we
* go through the vdev's checkpoint space map and exclude all
* its entries from their relevant ms_allocatable.
*
* We also aggregate the space held by the checkpoint and add
* it to zcb_checkpoint_size.
*
* Note that at this point we are also verifying that all the
* entries on the checkpoint_sm are marked as allocated in
* the ms_sm of their relevant metaslab.
* [see comment in checkpoint_sm_exclude_entry_cb()]
*/
zdb_leak_init_exclude_checkpoint(spa, zcb);
/*
* For leak detection, we overload the ms_allocatable trees
* to contain allocated segments instead of free segments.
* As a result, we can't use the normal metaslab_load/unload
* interfaces.
*/
zdb_leak_init_prepare_indirect_vdevs(spa, zcb);
load_concrete_ms_allocatable_trees(spa, SM_ALLOC);
/* for cleaner progress output */
(void) fprintf(stderr, "\n");
/*
* On load_concrete_ms_allocatable_trees() we loaded all the
* allocated entries from the ms_sm to the ms_allocatable for
* each metaslab. If the pool has a checkpoint or is in the
* middle of discarding a checkpoint, some of these blocks
* may have been freed but their ms_sm may not have been
* updated because they are referenced by the checkpoint. In
* order to avoid false-positives during leak-detection, we
* go through the vdev's checkpoint space map and exclude all
* its entries from their relevant ms_allocatable.
*
* We also aggregate the space held by the checkpoint and add
* it to zcb_checkpoint_size.
*
* Note that at this point we are also verifying that all the
* entries on the checkpoint_sm are marked as allocated in
* the ms_sm of their relevant metaslab.
* [see comment in checkpoint_sm_exclude_entry_cb()]
*/
zdb_leak_init_exclude_checkpoint(spa, zcb);
ASSERT3U(zcb->zcb_checkpoint_size, ==, spa_get_checkpoint_space(spa));
if (bpobj_is_open(&dp->dp_obsolete_bpobj)) {
ASSERT(spa_feature_is_enabled(spa,
SPA_FEATURE_DEVICE_REMOVAL));
(void) bpobj_iterate_nofree(&dp->dp_obsolete_bpobj,
increment_indirect_mapping_cb, zcb, NULL);
}
} else {
/*
* If leak tracing is disabled, we still need to consider
* any checkpointed space in our space verification.
*/
zcb->zcb_checkpoint_size += spa_get_checkpoint_space(spa);
/* for cleaner progress output */
(void) fprintf(stderr, "\n");
if (bpobj_is_open(&dp->dp_obsolete_bpobj)) {
ASSERT(spa_feature_is_enabled(spa,
SPA_FEATURE_DEVICE_REMOVAL));
(void) bpobj_iterate_nofree(&dp->dp_obsolete_bpobj,
increment_indirect_mapping_cb, zcb, NULL);
}
spa_config_enter(spa, SCL_CONFIG, FTAG, RW_READER);
@ -4125,51 +4130,54 @@ zdb_check_for_obsolete_leaks(vdev_t *vd, zdb_cb_t *zcb)
static boolean_t
zdb_leak_fini(spa_t *spa, zdb_cb_t *zcb)
{
if (dump_opt['L'])
return (B_FALSE);
boolean_t leaks = B_FALSE;
if (!dump_opt['L']) {
vdev_t *rvd = spa->spa_root_vdev;
for (unsigned c = 0; c < rvd->vdev_children; c++) {
vdev_t *vd = rvd->vdev_child[c];
ASSERTV(metaslab_group_t *mg = vd->vdev_mg);
vdev_t *rvd = spa->spa_root_vdev;
for (unsigned c = 0; c < rvd->vdev_children; c++) {
vdev_t *vd = rvd->vdev_child[c];
ASSERTV(metaslab_group_t *mg = vd->vdev_mg);
if (zcb->zcb_vd_obsolete_counts[c] != NULL) {
leaks |= zdb_check_for_obsolete_leaks(vd, zcb);
}
for (uint64_t m = 0; m < vd->vdev_ms_count; m++) {
metaslab_t *msp = vd->vdev_ms[m];
ASSERT3P(mg, ==, msp->ms_group);
/*
* ms_allocatable has been overloaded
* to contain allocated segments. Now that
* we finished traversing all blocks, any
* block that remains in the ms_allocatable
* represents an allocated block that we
* did not claim during the traversal.
* Claimed blocks would have been removed
* from the ms_allocatable. For indirect
* vdevs, space remaining in the tree
* represents parts of the mapping that are
* not referenced, which is not a bug.
*/
if (vd->vdev_ops == &vdev_indirect_ops) {
range_tree_vacate(msp->ms_allocatable,
NULL, NULL);
} else {
range_tree_vacate(msp->ms_allocatable,
zdb_leak, vd);
}
if (msp->ms_loaded)
msp->ms_loaded = B_FALSE;
}
if (zcb->zcb_vd_obsolete_counts[c] != NULL) {
leaks |= zdb_check_for_obsolete_leaks(vd, zcb);
}
umem_free(zcb->zcb_vd_obsolete_counts,
rvd->vdev_children * sizeof (uint32_t *));
zcb->zcb_vd_obsolete_counts = NULL;
for (uint64_t m = 0; m < vd->vdev_ms_count; m++) {
metaslab_t *msp = vd->vdev_ms[m];
ASSERT3P(mg, ==, msp->ms_group);
/*
* ms_allocatable has been overloaded
* to contain allocated segments. Now that
* we finished traversing all blocks, any
* block that remains in the ms_allocatable
* represents an allocated block that we
* did not claim during the traversal.
* Claimed blocks would have been removed
* from the ms_allocatable. For indirect
* vdevs, space remaining in the tree
* represents parts of the mapping that are
* not referenced, which is not a bug.
*/
if (vd->vdev_ops == &vdev_indirect_ops) {
range_tree_vacate(msp->ms_allocatable,
NULL, NULL);
} else {
range_tree_vacate(msp->ms_allocatable,
zdb_leak, vd);
}
if (msp->ms_loaded) {
msp->ms_loaded = B_FALSE;
}
}
}
umem_free(zcb->zcb_vd_obsolete_counts,
rvd->vdev_children * sizeof (uint32_t *));
zcb->zcb_vd_obsolete_counts = NULL;
return (leaks);
}
@ -4210,12 +4218,16 @@ dump_block_stats(spa_t *spa)
!dump_opt['L'] ? "nothing leaked " : "");
/*
* Load all space maps as SM_ALLOC maps, then traverse the pool
* claiming each block we discover. If the pool is perfectly
* consistent, the space maps will be empty when we're done.
* Anything left over is a leak; any block we can't claim (because
* it's not part of any space map) is a double allocation,
* reference to a freed block, or an unclaimed log block.
* When leak detection is enabled we load all space maps as SM_ALLOC
* maps, then traverse the pool claiming each block we discover. If
* the pool is perfectly consistent, the segment trees will be empty
* when we're done. Anything left over is a leak; any block we can't
* claim (because it's not part of any space map) is a double
* allocation, reference to a freed block, or an unclaimed log block.
*
* When leak detection is disabled (-L option) we still traverse the
* pool claiming each block we discover, but we skip opening any space
* maps.
*/
bzero(&zcb, sizeof (zdb_cb_t));
zdb_leak_init(spa, &zcb);
@ -4296,11 +4308,10 @@ dump_block_stats(spa_t *spa)
total_found = tzb->zb_asize - zcb.zcb_dedup_asize +
zcb.zcb_removing_size + zcb.zcb_checkpoint_size;
if (total_found == total_alloc) {
if (!dump_opt['L'])
(void) printf("\n\tNo leaks (block sum matches space"
" maps exactly)\n");
} else {
if (total_found == total_alloc && !dump_opt['L']) {
(void) printf("\n\tNo leaks (block sum matches space"
" maps exactly)\n");
} else if (!dump_opt['L']) {
(void) printf("block traversal size %llu != alloc %llu "
"(%s %lld)\n",
(u_longlong_t)total_found,
@ -5022,6 +5033,8 @@ verify_checkpoint_ms_spacemaps(spa_t *checkpoint, spa_t *current)
static void
verify_checkpoint_blocks(spa_t *spa)
{
ASSERT(!dump_opt['L']);
spa_t *checkpoint_spa;
char *checkpoint_pool;
nvlist_t *config = NULL;

4
man/man8/zdb.8
View File

@ -10,7 +10,7 @@
.\"
.\"
.\" Copyright 2012, Richard Lowe.
.\" Copyright (c) 2012, 2017 by Delphix. All rights reserved.
.\" Copyright (c) 2012, 2018 by Delphix. All rights reserved.
.\" Copyright 2017 Nexenta Systems, Inc.
.\" Copyright (c) 2017 Lawrence Livermore National Security, LLC.
.\" Copyright (c) 2017 Intel Corporation.
@ -194,7 +194,7 @@ If the
option is also specified, also display the uberblocks on this device. Specify
multiple times to increase verbosity.
.It Fl L
Disable leak tracing and the loading of space maps.
Disable leak detection and the loading of space maps.
By default,
.Nm
verifies that all non-free blocks are referenced, which can be very expensive.