Template Version: @(#)sac_nextcase 1.64 07/13/07 SMI
This information is Copyright 2007 Sun Microsystems
1. Introduction
   1.1. Project/Component Working Name:
        A_MDEV removal
   1.2. Name of Document Author/Supplier:
        Author:  Rich Morris
   1.3  Date of This Document:
        6 December, 2007
4. Technical Description

PSARC 2007/315 (Extensible Attribute Interfaces) was approved on 
13 June, 2007, and introduced a set of optional system-level file
attributes.  The A_MDEV attribute is one of the system attributes.
This attribute represents the mounted file system device which is
also returned by the stat(2) system call in st_dev.

This value was included in the SUNWattr_ro extended attribute file
for completeness.  However, the mount device is a 32 bit value on 
a 32 bit system and a 64 bit value on 64 bit system.  fgetattr(3c)
could be extended to provide both A_MDEV32 and A_MDEV64 attrs in 
the returned nvlist.  However, this would require support for 32 
bit applications to convert a 32 bit dev_t to and from a 64 bit 
dev_t.  Also, for an NFS remote file, fgetattr(3c) will not return 
the mount device of the NFS mount, but of the file system on the
server.  That is not the same value returned by stat(2) in st_dev.

Therefore, A_MDEV will be removed from SUNWattr_ro and will not be
returned by fgetattr(3c).  Applications should continue to obtain 
the mount device using stat(2). 

The changes originally approved by PSARC 2007/315 (Extensible Attribute
Interfaces) were putback into Solaris Nevada on 25 October 2007.

Section 4.1.1 of PSARC 2007/315 shows 2 attributes in XATTR_VIEW_READONLY:

 	 View                  Attribute               Data type
 	 XATTR_VIEW_READONLY   A_FSID                  uint64_t
  	                       A_MDEV                  uint16_t

A_AV_SCANSTAMP was added to XATTR_VIEW_READONLY by PSARC/2007/118 and
A_OPAQUE was added to this view by PSARC/2007/476.  This case removes 
A_MDEV so XATTR_VIEW_READONLY now has 3 attributes:

        View                  Attribute               Data type
        XATTR_VIEW_READONLY   A_FSID                  uint64_t        
                              A_AV_SCANSTAMP          uint8_array[]   
                              A_OPAQUE                boolean_value   


6. Resources and Schedule
   6.4. Steering Committee requested information
       6.4.1. Consolidation C-team Name:
               ON
   6.5. ARC review type: Automatic
   6.6. ARC Exposure: open