NFS: prepare coalesce testing for directio

The coalesce code made assumptions that will no longer be true once
non-page aligned io occurs.  This introduces no change in
current behavior, but allows for more general situations to come.

Signed-off-by: Fred Isaman <iisaman@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
This commit is contained in:
Fred Isaman 2012-04-20 19:55:31 -04:00 committed by Trond Myklebust
parent 9533da2979
commit 1825a0d08f
3 changed files with 22 additions and 2 deletions

View File

@ -796,6 +796,16 @@ filelayout_pg_init_read(struct nfs_pageio_descriptor *pgio,
{
BUG_ON(pgio->pg_lseg != NULL);
if (req->wb_offset != req->wb_pgbase) {
/*
* Handling unaligned pages is difficult, because have to
* somehow split a req in two in certain cases in the
* pg.test code. Avoid this by just not using pnfs
* in this case.
*/
nfs_pageio_reset_read_mds(pgio);
return;
}
pgio->pg_lseg = pnfs_update_layout(pgio->pg_inode,
req->wb_context,
0,
@ -815,6 +825,8 @@ filelayout_pg_init_write(struct nfs_pageio_descriptor *pgio,
BUG_ON(pgio->pg_lseg != NULL);
if (req->wb_offset != req->wb_pgbase)
goto out_mds;
pgio->pg_lseg = pnfs_update_layout(pgio->pg_inode,
req->wb_context,
0,

View File

@ -280,12 +280,12 @@ static bool nfs_can_coalesce_requests(struct nfs_page *prev,
return false;
if (req->wb_context->state != prev->wb_context->state)
return false;
if (req->wb_index != (prev->wb_index + 1))
return false;
if (req->wb_pgbase != 0)
return false;
if (prev->wb_pgbase + prev->wb_bytes != PAGE_CACHE_SIZE)
return false;
if (req_offset(req) != req_offset(prev) + prev->wb_bytes)
return false;
return pgio->pg_ops->pg_test(pgio, prev, req);
}

View File

@ -1082,6 +1082,10 @@ pnfs_generic_pg_init_read(struct nfs_pageio_descriptor *pgio, struct nfs_page *r
{
BUG_ON(pgio->pg_lseg != NULL);
if (req->wb_offset != req->wb_pgbase) {
nfs_pageio_reset_read_mds(pgio);
return;
}
pgio->pg_lseg = pnfs_update_layout(pgio->pg_inode,
req->wb_context,
req_offset(req),
@ -1100,6 +1104,10 @@ pnfs_generic_pg_init_write(struct nfs_pageio_descriptor *pgio, struct nfs_page *
{
BUG_ON(pgio->pg_lseg != NULL);
if (req->wb_offset != req->wb_pgbase) {
nfs_pageio_reset_write_mds(pgio);
return;
}
pgio->pg_lseg = pnfs_update_layout(pgio->pg_inode,
req->wb_context,
req_offset(req),