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, 1 insertions, 1 deletions

diff --git a/module/zfs/dsl_bookmark.c b/module/zfs/dsl_bookmark.c
index e5feadc51..a4cb361d4 100644
--- a/module/zfs/dsl_bookmark.c
+++ b/module/zfs/dsl_bookmark.c
@@ -120,7 +120,7 @@ dsl_bookmark_create_check_impl(dsl_dataset_t *snapds, const char *bookmark_name,
 	int error;
 	zfs_bookmark_phys_t bmark_phys;
 
-	if (!dsl_dataset_is_snapshot(snapds))
+	if (!snapds->ds_is_snapshot)
 		return (SET_ERROR(EINVAL));
 
 	error = dsl_bookmark_hold_ds(dp, bookmark_name,