From cfe7f4120f8b1b9465c333d1e42efd4669b1799f Mon Sep 17 00:00:00 2001 From: Fred Isaman Date: Tue, 1 Mar 2011 01:34:18 +0000 Subject: NFSv4.1: filelayout i/o helpers Prepare for filelayout_read_pagelist with helper functions that find the correct data server, filehandle, and offset. Signed-off-by: Andy Adamson Signed-off-by: Dean Hildebrand Signed-off-by: Fred Isaman Signed-off-by: Marc Eshel Signed-off-by: Mike Sager Signed-off-by: Oleg Drokin Signed-off-by: Tao Guo Signed-off-by: Tigran Mkrtchyan Signed-off-by: Tigran Mkrtchyan Signed-off-by: Andy Adamson Signed-off-by: Benny Halevy Signed-off-by: Trond Myklebust --- fs/nfs/nfs4filelayout.c | 34 ++++++++++++++++++++++++++++++++++ 1 file changed, 34 insertions(+) (limited to 'fs/nfs/nfs4filelayout.c') diff --git a/fs/nfs/nfs4filelayout.c b/fs/nfs/nfs4filelayout.c index 0efe8cbd9e3c..ed833705dcee 100644 --- a/fs/nfs/nfs4filelayout.c +++ b/fs/nfs/nfs4filelayout.c @@ -66,6 +66,40 @@ filelayout_clear_layoutdriver(struct nfs_server *nfss) return 0; } +static loff_t +filelayout_get_dense_offset(struct nfs4_filelayout_segment *flseg, + loff_t offset) +{ + u32 stripe_width = flseg->stripe_unit * flseg->dsaddr->stripe_count; + u64 tmp; + + offset -= flseg->pattern_offset; + tmp = offset; + do_div(tmp, stripe_width); + + return tmp * flseg->stripe_unit + do_div(offset, flseg->stripe_unit); +} + +/* This function is used by the layout driver to calculate the + * offset of the file on the dserver based on whether the + * layout type is STRIPE_DENSE or STRIPE_SPARSE + */ +static loff_t +filelayout_get_dserver_offset(struct pnfs_layout_segment *lseg, loff_t offset) +{ + struct nfs4_filelayout_segment *flseg = FILELAYOUT_LSEG(lseg); + + switch (flseg->stripe_type) { + case STRIPE_SPARSE: + return offset; + + case STRIPE_DENSE: + return filelayout_get_dense_offset(flseg, offset); + } + + BUG(); +} + /* * filelayout_check_layout() * -- cgit v1.2.3