pnfs: Use byte-range for layoutget
Add offset and count parameters to pnfs_update_layout and use them to get
the layout in the pageio path.
Order cache layout segments in the following order:
* offset (ascending)
* length (descending)
* iomode (RW before READ)
Test byte range against the layout segment in use in pnfs_{read,write}_pg_test
so not to coalesce pages not using the same layout segment.
[fix lseg ordering]
[clean up pnfs_find_lseg lseg arg]
[remove unnecessary FIXME]
[fix ordering in pnfs_insert_layout]
[clean up pnfs_insert_layout]
Signed-off-by: Benny Halevy <bhalevy@panasas.com>
diff --git a/fs/nfs/read.c b/fs/nfs/read.c
index 2bcf0dc..540c8bc 100644
--- a/fs/nfs/read.c
+++ b/fs/nfs/read.c
@@ -288,7 +288,9 @@
atomic_set(&req->wb_complete, requests);
BUG_ON(desc->pg_lseg != NULL);
- lseg = pnfs_update_layout(desc->pg_inode, req->wb_context, IOMODE_READ, GFP_KERNEL);
+ lseg = pnfs_update_layout(desc->pg_inode, req->wb_context,
+ req_offset(req), desc->pg_count,
+ IOMODE_READ, GFP_KERNEL);
ClearPageError(page);
offset = 0;
nbytes = desc->pg_count;
@@ -351,7 +353,9 @@
}
req = nfs_list_entry(data->pages.next);
if ((!lseg) && list_is_singular(&data->pages))
- lseg = pnfs_update_layout(desc->pg_inode, req->wb_context, IOMODE_READ, GFP_KERNEL);
+ lseg = pnfs_update_layout(desc->pg_inode, req->wb_context,
+ req_offset(req), desc->pg_count,
+ IOMODE_READ, GFP_KERNEL);
ret = nfs_read_rpcsetup(req, data, &nfs_read_full_ops, desc->pg_count,
0, lseg);