5056 ZFS deadlock on db_mtx and dn_holds
Reviewed by: Will Andrews <willa@spectralogic.com>
Reviewed by: Matt Ahrens <mahrens@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Approved by: Dan McDonald <danmcd@omniti.com>

@@ -21,10 +21,11 @@
 /*
  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2013 by Delphix. All rights reserved.
  * Copyright (c) 2013, Joyent, Inc. All rights reserved.
  * Copyright (c) 2013 Steven Hartland. All rights reserved.
+ * Copyright (c) 2014 Spectra Logic Corporation, All rights reserved.
  */
 
 #ifndef _SYS_DSL_DATASET_H
 #define _SYS_DSL_DATASET_H
 

@@ -130,15 +131,18 @@
         uint64_t ds_userrefs_obj;       /* DMU_OT_USERREFS */
         uint64_t ds_pad[5]; /* pad out to 320 bytes for good measure */
 } dsl_dataset_phys_t;
 
 typedef struct dsl_dataset {
+        dmu_buf_user_t ds_dbu;
+
         /* Immutable: */
         struct dsl_dir *ds_dir;
         dmu_buf_t *ds_dbuf;
         uint64_t ds_object;
         uint64_t ds_fsid_guid;
+        boolean_t ds_is_snapshot;
 
         /* only used in syncing context, only valid for non-snapshots: */
         struct dsl_dataset *ds_prev;
         uint64_t ds_bookmarks;  /* DMU_OTN_ZAP_METADATA */
         boolean_t ds_large_blocks;

@@ -195,16 +199,10 @@
  * The max length of a temporary tag prefix is the number of hex digits
  * required to express UINT64_MAX plus one for the hyphen.
  */
 #define MAX_TAG_PREFIX_LEN      17
 
-inline boolean_t
-dsl_dataset_is_snapshot(dsl_dataset_t *ds)
-{
-        return (dsl_dataset_phys(ds)->ds_num_children != 0);
-}
-
 #define DS_UNIQUE_IS_ACCURATE(ds)       \
         ((dsl_dataset_phys(ds)->ds_flags & DS_FLAG_UNIQUE_ACCURATE) != 0)
 
 int dsl_dataset_hold(struct dsl_pool *dp, const char *name, void *tag,
     dsl_dataset_t **dsp);