OpenZFS 742 - Resurrect the ZFS "aclmode" property OpenZFS 664 - Umask masking "deny" ACL entries OpenZFS 279 - Bug in the new ACL (post-PSARC/2010/029) semantics

Porting notes:
* Updated zfs_acl_chmod to take 'boolean_t isdir' as first parameter
  rather than 'zfsvfs_t *zfsvfs'
* zfs man pages changes mixed between zfs and new zfsprops man pages

Reviewed by: Aram Hvrneanu <aram@nexenta.com>
Reviewed by: Gordon Ross <gwr@nexenta.com>
Reviewed by: Robert Gordon <rbg@openrbg.com>
Reviewed by: Mark.Maybee@oracle.com
Reviewed by: Brian Behlendorf <behlendorf1@llnl.gov>
Approved by: Garrett D'Amore <garrett@nexenta.com>
Ported-by: Paul B. Henson <henson@acm.org>

OpenZFS-issue: https://www.illumos.org/issues/742
OpenZFS-issue: https://www.illumos.org/issues/664
OpenZFS-issue: https://www.illumos.org/issues/279
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/a3c49ce110
Closes #10266

man/man8/zfsprops.8

@@ -599,23 +599,24 @@ accordance to the requested mode from the application.
 The
 .Sy aclinherit
 property does not apply to POSIX ACLs.
-.It Sy aclmode Ns = Ns Sy discard Ns | Ns Sy groupmask Ns | Ns Sy passthrough
-.Ns Sy restricted
-Controls how an
-.Tn ACL
-is modified during
-.Xr chmod 2 .
-This property is not visible on Linux yet.
+.It Xo
+.Sy aclmode Ns = Ns Sy discard Ns | Ns Sy groupmask Ns | Ns
+.Sy passthrough Ns
+.Xc
+Controls how an ACL is modified during chmod(2) and how inherited ACEs
+are modified by the file creation mode.
 .Bl -tag -width "passthrough"
 .It Sy discard
 default, deletes all
-.Tn ACL
-entries that do not represent the mode of the file.
+.Sy ACEs
+except for those representing
+the mode of the file or directory requested by
+.Xr chmod 2 .
 .It Sy groupmask
 reduces permissions granted in all
-.Em ALLOW
-entried found in the
-.Tn ACL
+.Sy ALLOW
+entries found in the
+.Sy ACL
 such that they are no greater than the group permissions specified by
 .Xr chmod 2 .
 .It Sy passthrough