Illumos 5056 - ZFS deadlock on db_mtx and dn_holds

5056 ZFS deadlock on db_mtx and dn_holds
Author: Justin Gibbs <[email protected]>
Reviewed by: Will Andrews <[email protected]>
Reviewed by: Matt Ahrens <[email protected]>
Reviewed by: George Wilson <[email protected]>
Approved by: Dan McDonald <[email protected]>

References:
  https://www.illumos.org/issues/5056
  https://github.com/illumos/illumos-gate/commit/bc9014e

Porting Notes:

sa_handle_get_from_db():
  - the original patch includes an otherwise unmentioned fix for a
    possible usage of an uninitialised variable

dmu_objset_open_impl():
  - Under Illumos list_link_init() is the same as filling a list_node_t
    with NULLs, so they don't notice if they miss doing list_link_init()
    on a zero'd containing structure (e.g. allocated with kmem_zalloc as
    here). Under Linux, not so much: an uninitialised list_node_t goes
    "Boom!" some time later when it's used or destroyed.

dmu_objset_evict_dbufs():
  - reduce stack usage using kmem_alloc()

Ported-by: Chris Dunlop <[email protected]>
Signed-off-by: Brian Behlendorf <[email protected]>

1 files changed, 0 insertions, 1 deletions

diff --git a/include/sys/sa.h b/include/sys/sa.h
index 7b5b03a56..48e3bcd7c 100644
--- a/include/sys/sa.h
+++ b/include/sys/sa.h
@@ -133,7 +133,6 @@ int sa_update_from_cb(sa_handle_t *, sa_attr_type_t,
     uint32_t buflen, sa_data_locator_t *, void *userdata, dmu_tx_t *);
 void sa_object_info(sa_handle_t *, dmu_object_info_t *);
 void sa_object_size(sa_handle_t *, uint32_t *, u_longlong_t *);
-void sa_update_user(sa_handle_t *, sa_handle_t *);
 void *sa_get_userdata(sa_handle_t *);
 void sa_set_userp(sa_handle_t *, void *);
 dmu_buf_t *sa_get_db(sa_handle_t *);