On 2011-12-03 06:52, Peng Tao wrote:
> This gives LD option not to ask for layout in pg_init.
>
> Signed-off-by: Peng Tao <peng_tao@xxxxxxx>
> ---
> fs/nfs/pnfs.c | 46 ++++++++++++++++++++++++++++++++++++++++++++++
> 1 files changed, 46 insertions(+), 0 deletions(-)
>
> diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
> index 734e670..c8dc0b1 100644
> --- a/fs/nfs/pnfs.c
> +++ b/fs/nfs/pnfs.c
> @@ -1254,6 +1254,7 @@ pnfs_do_multiple_writes(struct nfs_pageio_descriptor *desc, struct list_head *he
> struct nfs_write_data *data;
> const struct rpc_call_ops *call_ops = desc->pg_rpc_callops;
> struct pnfs_layout_segment *lseg = desc->pg_lseg;
> + const bool has_lseg = !!lseg;
nit: "has_lseg = (lseg != NULL)" would be more straight forward IMO
>
> desc->pg_lseg = NULL;
> while (!list_empty(head)) {
> @@ -1262,7 +1263,29 @@ pnfs_do_multiple_writes(struct nfs_pageio_descriptor *desc, struct list_head *he
> data = list_entry(head->next, struct nfs_write_data, list);
> list_del_init(&data->list);
>
> + if (!has_lseg) {
> + struct nfs_page *req = nfs_list_entry(data->pages.next);
> + __u64 length = data->npages << PAGE_CACHE_SHIFT;
> +
> + lseg = pnfs_update_layout(desc->pg_inode,
> + req->wb_context,
> + req_offset(req),
> + length,
> + IOMODE_RW,
> + GFP_NOFS);
> + if (!lseg || length > (lseg->pls_range.length)) {
I'm concerned about the 'length' part of this condition.
pnfs_try_to_write_data should handle short writes/reads and
we should be able to iterate through the I/O using different
layout segments.
> + put_lseg(lseg);
> + lseg = NULL;
> + pnfs_write_through_mds(desc,data);
> + continue;
> + }
> + }
> +
> trypnfs = pnfs_try_to_write_data(data, call_ops, lseg, how);
> + if (!has_lseg) {
> + put_lseg(lseg);
> + lseg = NULL;
> + }
We had an implementation in the past that saved the most recent lseg in 'desc'
so it could be used for the remaining requests. Once exhausted, you can
look for a new one.
> if (trypnfs == PNFS_NOT_ATTEMPTED)
> pnfs_write_through_mds(desc, data);
> }
> @@ -1350,6 +1373,7 @@ pnfs_do_multiple_reads(struct nfs_pageio_descriptor *desc, struct list_head *hea
> struct nfs_read_data *data;
> const struct rpc_call_ops *call_ops = desc->pg_rpc_callops;
> struct pnfs_layout_segment *lseg = desc->pg_lseg;
> + const bool has_lseg = !!lseg;
ditto
>
> desc->pg_lseg = NULL;
> while (!list_empty(head)) {
> @@ -1358,7 +1382,29 @@ pnfs_do_multiple_reads(struct nfs_pageio_descriptor *desc, struct list_head *hea
> data = list_entry(head->next, struct nfs_read_data, list);
> list_del_init(&data->list);
>
> + if (!has_lseg) {
> + struct nfs_page *req = nfs_list_entry(data->pages.next);
> + __u64 length = data->npages << PAGE_CACHE_SHIFT;
> +
> + lseg = pnfs_update_layout(desc->pg_inode,
> + req->wb_context,
> + req_offset(req),
> + length,
> + IOMODE_READ,
> + GFP_KERNEL);
> + if (!lseg || length > lseg->pls_range.length) {
> + put_lseg(lseg);
> + lseg = NULL;
> + pnfs_read_through_mds(desc, data);
> + continue;
> + }
> + }
> +
> trypnfs = pnfs_try_to_read_data(data, call_ops, lseg);
> + if (!has_lseg) {
> + put_lseg(lseg);
> + lseg = NULL;
> + }
ditto
Benny
> if (trypnfs == PNFS_NOT_ATTEMPTED)
> pnfs_read_through_mds(desc, data);
> }
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