Fix scn_queue races on very old poolsstable/13

Code for pools before version 11 uses dmu_objset_find_dp() to scan
for children datasets/clones.  It calls enqueue_clones_cb() and
enqueue_cb() callbacks in parallel from multiple taskq threads.
It ends up bad for scan_ds_queue_insert(), corrupting scn_queue
AVL-tree.  Fix it by introducing a mutex to protect those two
scan_ds_queue_insert() calls.  All other calls are done from the
sync thread and so serialized.

Reviewed-by:	Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by:	Brian Atkinson <batkinson@lanl.gov>
Signed-off-by:	Alexander Motin <mav@FreeBSD.org>
Sponsored by:	iXsystems, Inc.
Closes	#16162
PR:	278414

(cherry picked from commit 49086aa35d987b78dbc3c9ec94814fe338e07164)

0 files changed, 0 insertions, 0 deletions