7801 add more by-dnode routines
illumos/illumos-gate@b0c42cd4706ba01ce158bd2bb1004f7e59eca5fe
https://github.com/illumos/illumos-gate/commit/b0c42cd4706ba01ce158bd2bb1004f7e59eca5fe
https://www.illumos.org/issues/7801
Add *_by_dnode() routines for accessing objects given their dnode_t *, this is more efficient than accessing the object by (objset_t *, uint64_t object). This change converts some but not all of the existing consumers. As performance-sensitive code paths are discovered they should be converted to use these routines. Ported from: https://github.com/zfsonlinux/zfs/commit/ 0eef1bde31d67091d3deed23fe2394f5a8bf2276
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed by: Pavel Zakharov <pavel.zakharov@delphix.com>
Approved by: Robert Mustacchi <rm@joyent.com>
Author: bzzz77 <bzzz.tomas@gmail.com>