Commit a1d477c2 accidentally disabled DTL updates for the zil_claim()
case described at the end of vdev_stat_update() by unconditionally
disabling all DTL updates when loading. This was done to avoid
a deadlock on the vd_dtl_lock when loading the DTLs from disk.
vdev_dtl_contains <--- Takes vd->vd_dtl_lock
vdev_mirror_child_missing
vdev_mirror_io_start
zio_vdev_io_start
__zio_execute
arc_read
dbuf_issue_final_prefetch
dbuf_prefetch_impl
dbuf_prefetch
dmu_prefetch
space_map_iterate
space_map_load_length
space_map_load
vdev_dtl_load <--- Takes vd->vd_dtl_lock
vdev_load
spa_ld_load_vdev_metadata
spa_tryimport
The missing DTL updates can be restored by moving the space_map_load()
call outside the vd_dtl_lock. A private range tree is populated by
reading the space map and then merged in to the DTL_MISSING tree
under the lock.
Furthermore, the SPA_LOAD_NONE check in vdev_dtl_contains() leads to an
additional problem. Any resilvering which occurs before SPA_LOAD_NONE
is set will incorrectly determine that there's nothing to repair. This
can result in full redundancy not being restored for some blocks.
Reviewed-by: Matt Ahrens <matt@delphix.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#11218
ccfa35c6f9