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authorFred Isaman <iisaman@netapp.com>2011-03-01 01:34:18 +0000
committerTrond Myklebust <Trond.Myklebust@netapp.com>2011-03-11 15:38:42 -0500
commitcfe7f4120f8b1b9465c333d1e42efd4669b1799f (patch)
treea55e5fc7dbafdf43588a480a0348da0ad8e1eb9e /fs/nfs/nfs4filelayout.c
parentd83217c13531fd59730d77b5c2284e90e56c0a50 (diff)
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 <andros@citi.umich.edu> Signed-off-by: Dean Hildebrand <dhildeb@us.ibm.com> Signed-off-by: Fred Isaman <iisaman@netapp.com> Signed-off-by: Marc Eshel <eshel@almaden.ibm.com> Signed-off-by: Mike Sager <sager@netapp.com> Signed-off-by: Oleg Drokin <green@linuxhacker.ru> Signed-off-by: Tao Guo <guotao@nrchpc.ac.cn> Signed-off-by: Tigran Mkrtchyan <tigran@anahit.desy.de> Signed-off-by: Tigran Mkrtchyan <tigran.mkrtchyan@desy.de> Signed-off-by: Andy Adamson <andros@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Diffstat (limited to 'fs/nfs/nfs4filelayout.c')
-rw-r--r--fs/nfs/nfs4filelayout.c34
1 files changed, 34 insertions, 0 deletions
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()
*