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Fix zdb -c traverse stop on damaged objset root 

If a corruption happens to be on a root block of an objset, zdb -c will
not correctly report the error, and it will not traverse the datasets
that come after. This is because traverse_visitbp, which does the
callback and reset error for TRAVERSE_HARD, is skipped when traversing
zil is failed in traverse_impl.

Here's example of what 'zdb -eLcc' command looks like on a pool with
damaged objset root:

== before patch:

Traversing all blocks to verify checksums ...

Error counts:

	errno  count
block traversal size 379392 != alloc 33987072 (unreachable 33607680)

	bp count:             172
	ganged count:           0
	bp logical:       1678336      avg:   9757
	bp physical:       130560      avg:    759     compression:  12.85
	bp allocated:      379392      avg:   2205     compression:   4.42
	bp deduped:             0    ref>1:      0   deduplication:   1.00
	SPA allocated:   33987072     used:  0.80%

	additional, non-pointer bps of type 0:         71
	Dittoed blocks on same vdev: 101

== after patch:

Traversing all blocks to verify checksums ...

zdb_blkptr_cb: Got error 52 reading <54, 0, -1, 0>  -- skipping

Error counts:

	errno  count
	   52  1
block traversal size 33963520 != alloc 33987072 (unreachable 23552)

	bp count:             447
	ganged count:           0
	bp logical:      36093440      avg:  80745
	bp physical:     33699840      avg:  75391     compression:   1.07
	bp allocated:    33963520      avg:  75981     compression:   1.06
	bp deduped:             0    ref>1:      0   deduplication:   1.00
	SPA allocated:   33987072     used:  0.80%

	additional, non-pointer bps of type 0:         76
	Dittoed blocks on same vdev: 115

==

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: loli10K <ezomori.nozomu@gmail.com>
Signed-off-by: Chunwei Chen <david.chen@nutanix.com>
Closes #7099
This commit is contained in:
Chunwei Chen 2018-01-30 13:39:11 -08:00 committed by Tony Hutter
parent 3713b73335
commit 23227313a2
1 changed files with 17 additions and 9 deletions
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18
module/zfs/dmu_traverse.c
View File

@ -599,20 +599,28 @@ traverse_impl(spa_t *spa, dsl_dataset_t *ds, uint64_t objset, blkptr_t *rootbp,
/* See comment on ZIL traversal in dsl_scan_visitds. */
if (ds != NULL && !ds->ds_is_snapshot && !BP_IS_HOLE(rootbp)) {
enum zio_flag zio_flags = ZIO_FLAG_CANFAIL;
uint32_t flags = ARC_FLAG_WAIT;
objset_phys_t *osp;
arc_buf_t *buf;
err = arc_read(NULL, td->td_spa, rootbp,
arc_getbuf_func, &buf,
ZIO_PRIORITY_ASYNC_READ, ZIO_FLAG_CANFAIL, &flags, czb);
if (err != 0)
err = arc_read(NULL, td->td_spa, rootbp, arc_getbuf_func,
&buf, ZIO_PRIORITY_ASYNC_READ, zio_flags, &flags, czb);
if (err != 0) {
/*
* If both TRAVERSE_HARD and TRAVERSE_PRE are set,
* continue to visitbp so that td_func can be called
* in pre stage, and err will reset to zero.
*/
if (!(td->td_flags & TRAVERSE_HARD) ||
!(td->td_flags & TRAVERSE_PRE))
return (err);
} else {
osp = buf->b_data;
traverse_zil(td, &osp->os_zil_header);
arc_buf_destroy(buf, &buf);
}
}
if (!(flags & TRAVERSE_PREFETCH_DATA) ||
taskq_dispatch(system_taskq, traverse_prefetch_thread,