Support off-line files on SAM-QFS for Samba in Solaris [PSARC/2009/381 FastTrack timeout 07/13/2009]

[Daniel Hain]

I'm submitting this fasttrack for Jiri Sasek. This proposal seeks patch binding
and will timeout on 07/13/2009.

The listed imported interfaces from libsam.so are currently classified as Stable
by the last approved PSARC case (PSARC/2001/599/ SAM_FS and QFS 4.0). The case 
for SAM-QFS 5.0  (PSARC/2007/588) lists them as Unstable, but that case has not
been approved. Discussion with the SAM-QFS team indicates that they feel the 
classification of these interfaces is still Stable.

-Dan


Template Version: @(#)sac_nextcase 1.68 02/23/09 SMI
This information is Copyright 2009 Sun Microsystems
1. Introduction
    1.1. Project/Component Working Name:
	 Support off-line files on SAM-QFS for Samba in Solaris
    1.2. Name of Document Author/Supplier:
	 Author:  Jiri Sasek
    1.3  Date of This Document:
	06 July, 2009
4. Technical Description
Proposal:

        Support off-line files on SAM-QFS for Samba in Solaris.

Detail:

	Samba is CIFS volume and printing server.

	The current version of Samba (3.0.34) integrated in Solaris
        does not support off-line file attribute for files stored on
        a SAM-FS volume when located on an off-line storage (a tape).

	Such situation has the following consequences on MS Windows
        clients:

	 - Client's attempt to acces an off-line file will fail on 
           timeout which is set too short to access a file stored
           on a tape or any other external (off-line) storage.

	 - If MS Windows Eplorer's curent directory is set to
	   a directory full of off-lined files it causes a "storm"
	   of the tape changer arms when thumbnails are being generated.

        The solution is to let Samba use libsam.so library, [4], which
        provides the off-line information for files stored on a
        off-line storage (a tape).  Since this library is optional
        on Solaris then it is necessary to use lazy binding option for
        linking this library with Samba.  The lazy binding option makes
        sure that "smbd" (Samba daemon) will run even if libsamfs.so is
	not present on the system.

	When "samfs share = yes" configuration option is set in smb.conf
	(Samba configuration file) and libsamfs.so is not present on the
	system then calling the lazy linked library-call will not complete
	the dlopen(2) call successfuly and the standard message from the
	run-time linker notifying about is redirected from the stderr
	output to the "smbd" log file appropriate to the CIFS session
	serviced by this "smbd" daemon. Samba log files can be configured
	as described in smb.conf(4). In the standard distribution such log
	file is located on the "/var/samba/log/log.<hostname|IP>" path.

        SAM-FS library libsamfs.so is delivered by optional packages
	SUNWsamfsr SUNWsamfsu and should be installed from the external
	source.
     
Exported Interfaces: (uncommited)

   ---------------------------------------------------------------------
   FILE_ATTRIBUTE_OFFLINE flag (0x00001000) in "Attributes" of
   SMB_QUERY_FILE_BASIC_INFO response CIFS message will indicate the
   off/on-line file status of files located on SAM-QFS share

   ---------------------------------------------------------------------
   smb.conf option "samfs share = yes|no" (default: no)

Imported Interfaces:

   The following functions from libsamfs.so are used:

   ---------------------------------------------------------------------
   sam_stat()		| File status calls available from libsam library
   sam_segment_stat()	| returning the "struct sam_stat"

References:

[1] http://samba.org/
    Author(s) of Samba: Andrew Tridgel, Jeremy Alisson, Michael Adam...
    please check Samba.org to obtain the full list of the core team members
    please also check the source code for external contributors
[2] Common Internet File System (CIFS) Technical Reference (Revision: 1.0)
    http://snia.org/
[3] 6737005 samba should handle samfs WORM and offline files gracefully
[4] http://www.opensolaris.org/os/project/samqfs/sourcecode/



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