7143 dbuf_read() creates unnecessary zio_root() for bonus buf

openzfs · Jun 26, 2016 · dde13a0 · dde13a0
1 parent 87363ab
commit dde13a0
Showing 1 changed file with 4 additions and 3 deletions.
diff --git a/usr/src/uts/common/fs/zfs/dbuf.c b/usr/src/uts/common/fs/zfs/dbuf.c
@@ -21,7 +21,7 @@
 /*
  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
  * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
- * Copyright (c) 2012, 2015 by Delphix. All rights reserved.
+ * Copyright (c) 2012, 2016 by Delphix. All rights reserved.
  * Copyright (c) 2013 by Saso Kiselkov. All rights reserved.
  * Copyright (c) 2013, Joyent, Inc. All rights reserved.
  * Copyright (c) 2014 Spectra Logic Corporation, All rights reserved.
@@ -785,7 +785,8 @@ dbuf_read(dmu_buf_impl_t *db, zio_t *zio, uint32_t flags)
 	} else if (db->db_state == DB_UNCACHED) {
 		spa_t *spa = dn->dn_objset->os_spa;
 
-		if (zio == NULL)
+		if (zio == NULL &&
+		    db->db_blkptr != NULL && !BP_IS_HOLE(db->db_blkptr))
 			zio = zio_root(spa, NULL, NULL, ZIO_FLAG_CANFAIL);
 		dbuf_read_impl(db, zio, flags);
 
@@ -798,7 +799,7 @@ dbuf_read(dmu_buf_impl_t *db, zio_t *zio, uint32_t flags)
 			rw_exit(&dn->dn_struct_rwlock);
 		DB_DNODE_EXIT(db);
 
-		if (!havepzio)
+		if (!havepzio && zio != NULL)
 			err = zio_wait(zio);
 	} else {
 		/*