From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from relay.sgi.com (relay3.corp.sgi.com [198.149.34.15]) by oss.sgi.com (Postfix) with ESMTP id 4B30F7FC8 for ; Wed, 10 Apr 2013 14:39:05 -0500 (CDT) Message-ID: <5165BFF4.8020601@sgi.com> Date: Wed, 10 Apr 2013 14:39:32 -0500 From: Rich Johnston MIME-Version: 1.0 Subject: Re: [PATCH] xfs: reserve fields in inode for parent ptr and alloc policy References: <20130410182438.268267840@sgi.com> <5165B5CB.2070203@sandeen.net> In-Reply-To: <5165B5CB.2070203@sandeen.net> List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Errors-To: xfs-bounces@oss.sgi.com Sender: xfs-bounces@oss.sgi.com To: Eric Sandeen Cc: Mark Tinguely , xfs@oss.sgi.com On 04/10/2013 01:56 PM, Eric Sandeen wrote: > On 4/10/13 1:24 PM, Mark Tinguely wrote: >> Reserve fields in new inode layout for parent pointer and >> allocation policy. >> ---- >> The inode will hold the parent information for the first >> link to a file. Information for the other links will be >> held in extended attribute entries. >> >> The "di_parino" is the inode of the parent directory. The >> directory information for this entry is located the parent >> directory with "di_paroff" offset. >> >> The di_parino/di_paroff concept code is running. >> ---- >> The "di_allocpolicy" will be used to remember the allocation >> policy associated with this inode. > > can you say more about this allocation policy? > > -Eric No its super secret information. ;) Its on my plate Eric, because Mark was making a change for parent ptrs, I asked him to request space for allocation policies also. I don't have all the details yet but here is a very high level concept. Identify allocation groups by names (or numbers -- preferably using names in user-visible areas), allowing many different areas. Placing the allocation policy outside of user programs is necessary for this to be successful. Current thoughts on proposed a layered allocation policies: Policy for the entire filesystem Policy attached to a directory (whose policy would be inherited by subdirectories when subdirectories are created) Policy for a single file The policy would define: where to place file data where to place metadata for the files. a prefered allocation group for placing file data (for directories). --Rich _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs