From: Patrick Farrell <paf@xxxxxxxx> Add subsystem description from Di Wang to header file. Signed-off-by: Patrick Farrell <paf@xxxxxxxx> Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-5153 Reviewed-on: http://review.whamcloud.com/10631 Reviewed-by: wangdi <di.wang@xxxxxxxxx> Reviewed-by: John L. Hammond <john.hammond@xxxxxxxxx> Reviewed-by: Oleg Drokin <oleg.drokin@xxxxxxxxx> Signed-off-by: James Simmons <jsimmons@xxxxxxxxxxxxx> --- 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 <sequence_range, node_index> 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 <umka@xxxxxxxxxxxxx> * Author: Tom WangDi <wangdi@xxxxxxxxxxxxx> */ -- 1.7.1 _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
