Re: bin/45919: mount(8) manpage description of option union is unclear

[Julian Fagir <gnrp%komkon2.de@localhost>]

The following reply was made to PR bin/45919; it has been noted by GNATS.

From: Julian Fagir <gnrp%komkon2.de@localhost>
To: gnats-bugs%NetBSD.org@localhost
Cc: 
Subject: Re: bin/45919: mount(8) manpage description of option union is
 unclear
Date: Mon, 9 Apr 2012 21:08:54 +0200

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 Hi,
 
 apb proposed the following text rather than the one before, clearly written
 in a better language.
 
 Regards, Julian
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 Index: ./sbin/mount/mount.8
 ===================================================================
 RCS file: /cvsroot/src/sbin/mount/mount.8,v
 retrieving revision 1.74
 diff -u -r1.74 mount.8
 --- ./sbin/mount/mount.8       22 Jul 2011 15:53:21 -0000      1.74
 +++ ./sbin/mount/mount.8       9 Apr 2012 19:07:14 -0000
 @@ -303,12 +303,32 @@
  mode.
  .It Cm union
  Causes the namespace at the mount point to appear as the union
 -of the mounted file system root and the existing directory.
 -Lookups will be done in the mounted file system first.
 -If those operations fail due to a non-existent file the underlying
 -directory is then accessed.
 -All creates are done in the mounted file system, except for the fdesc
 -file system.
 +of the mounted file system root
 +(referred to as the
 +.Em upper
 +layer), and the existing directory
 +(referred to as the
 +.Em lower
 +layer).
 +Name lookups will be done in the upper layer first.
 +If a name does not exist in the upper layer, then the name
 +will be looked up in the lower layer.
 +If a name exists in both the upper and lower layers, then only
 +the upper instance is accessible.
 +Creation of new files is done in the upper layer,
 +except in the case of the fdesc file system (see
 +.Xr mount_fdesc 8 ) .
 +.Pp
 +Note that the
 +.Cm union
 +option can be applied to any type of file system,
 +and is fundamentally different from
 +.Xr mount_union 8 ,
 +which is a particular type of file system.
 +Also note that the
 +.Cm union
 +option affects the file system name space only at the mount point
 +itself; it does not apply recursively to subdirectories.
  .It Cm update
  The same as
  .Fl u ;
 
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