From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932548AbcHPUVP (ORCPT ); Tue, 16 Aug 2016 16:21:15 -0400 Received: from smtp1.ccs.ornl.gov ([160.91.203.10]:34054 "EHLO smtp1.ccs.ornl.gov" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932442AbcHPUVI (ORCPT ); Tue, 16 Aug 2016 16:21:08 -0400 From: James Simmons To: Greg Kroah-Hartman , devel@driverdev.osuosl.org, Andreas Dilger , Oleg Drokin Cc: Linux Kernel Mailing List , Lustre Development List , Patrick Farrell , James Simmons Subject: [PATCH 59/80] staging: lustre: fld: add fld description documentation Date: Tue, 16 Aug 2016 16:19:12 -0400 Message-Id: <1471378773-24590-60-git-send-email-jsimmons@infradead.org> X-Mailer: git-send-email 1.7.1 In-Reply-To: <1471378773-24590-1-git-send-email-jsimmons@infradead.org> References: <1471378773-24590-1-git-send-email-jsimmons@infradead.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Patrick Farrell Add subsystem description from Di Wang to header file. Signed-off-by: Patrick Farrell Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-5153 Reviewed-on: http://review.whamcloud.com/10631 Reviewed-by: wangdi Reviewed-by: John L. Hammond Reviewed-by: Oleg Drokin Signed-off-by: James Simmons --- drivers/staging/lustre/lustre/fld/fld_internal.h | 19 +++++++++++++++++++ 1 files changed, 19 insertions(+), 0 deletions(-) diff --git a/drivers/staging/lustre/lustre/fld/fld_internal.h b/drivers/staging/lustre/lustre/fld/fld_internal.h index f0efe5b..08eaec7 100644 --- a/drivers/staging/lustre/lustre/fld/fld_internal.h +++ b/drivers/staging/lustre/lustre/fld/fld_internal.h @@ -31,6 +31,25 @@ * * lustre/fld/fld_internal.h * + * Subsystem Description: + * FLD is FID Location Database, which stores where (IE, on which MDT) + * FIDs are located. + * The database is basically a record file, each record consists of a FID + * sequence range, MDT/OST index, and flags. The FLD for the whole FS + * is only stored on the sequence controller(MDT0) right now, but each target + * also has its local FLD, which only stores the local sequence. + * + * The FLD subsystem usually has two tasks: + * 1. maintain the database, i.e. when the sequence controller allocates + * new sequence ranges to some nodes, it will call the FLD API to insert the + * location information in FLDB. + * + * 2. Handle requests from other nodes, i.e. if client needs to know where + * the FID is located, if it can not find the information in the local cache, + * it will send a FLD lookup RPC to the FLD service, and the FLD service will + * look up the FLDB entry and return the location information to client. + * + * * Author: Yury Umanets * Author: Tom WangDi */ -- 1.7.1