[PATCH 12/22] pnfs_submit: read path changeover

[Fred Isaman <iisaman@netapp.com>]

Change readpages path to only call LAYOUTGET once.

Signed-off-by: Fred Isaman <iisaman@netapp.com>
---
 fs/nfs/pagelist.c |    2 ++
 fs/nfs/pnfs.c     |   37 +++++++------------------------------
 fs/nfs/pnfs.h     |   25 ++++++++++++++++---------
 3 files changed, 25 insertions(+), 39 deletions(-)

diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c
index 92fedbb..19ffdc5 100644
--- a/fs/nfs/pagelist.c
+++ b/fs/nfs/pagelist.c
@@ -259,6 +259,8 @@ static int nfs_can_coalesce_requests(struct nfs_page *prev,
 		return 0;
 	if (prev->wb_pgbase + prev->wb_bytes != PAGE_CACHE_SIZE)
 		return 0;
+	if (req->wb_lseg != prev->wb_lseg)
+		return 0;
 #ifdef CONFIG_NFS_V4_1
 	if (pgio->pg_test && !pgio->pg_test(pgio, prev, req))
 		return 0;
diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
index ddc4578..07a8c33 100644
--- a/fs/nfs/pnfs.c
+++ b/fs/nfs/pnfs.c
@@ -1690,7 +1690,7 @@ pnfs_readpages(struct nfs_read_data *rdata)
 {
 	struct nfs_readargs *args = &rdata->args;
 	struct inode *inode = rdata->inode;
-	int numpages, status, pgcount, temp;
+	int numpages, pgcount, temp;
 	struct nfs_server *nfss = NFS_SERVER(inode);
 	struct nfs_inode *nfsi = NFS_I(inode);
 	struct pnfs_layout_segment *lseg;
@@ -1702,19 +1702,8 @@ pnfs_readpages(struct nfs_read_data *rdata)
 		args->count,
 		args->offset);
 
-	/* Retrieve and set layout if not allready cached */
-	status = _pnfs_update_layout(inode,
-				    args->context,
-				    args->count,
-				    args->offset,
-				    IOMODE_READ,
-				    &lseg);
-	if (status) {
-		dprintk("%s: Updating layout failed (%d), retry with NFS \n",
-			__func__, status);
-		trypnfs = PNFS_NOT_ATTEMPTED;
-		goto out;
-	}
+	lseg = rdata->req->wb_lseg;
+	get_lseg(lseg);
 
 	/* Determine number of pages. */
 	pgcount = args->pgbase + args->count;
@@ -1741,7 +1730,6 @@ pnfs_readpages(struct nfs_read_data *rdata)
 		rdata->pdata.lseg = NULL;
 		put_lseg(lseg);
 	}
- out:
 	dprintk("%s End (trypnfs:%d)\n", __func__, trypnfs);
 	return trypnfs;
 }
@@ -1750,21 +1738,10 @@ enum pnfs_try_status
 _pnfs_try_to_read_data(struct nfs_read_data *data,
 		       const struct rpc_call_ops *call_ops)
 {
-	struct inode *ino = data->inode;
-	struct nfs_server *nfss = NFS_SERVER(ino);
-
-	dprintk("--> %s\n", __func__);
-	/* Only create an rpc request if utilizing NFSv4 I/O */
-	if (!pnfs_enabled_sb(nfss) ||
-	    !nfss->pnfs_curr_ld->ld_io_ops->read_pagelist) {
-		dprintk("<-- %s: not using pnfs\n", __func__);
-		return PNFS_NOT_ATTEMPTED;
-	} else {
-		dprintk("%s: Utilizing pNFS I/O\n", __func__);
-		data->pdata.call_ops = call_ops;
-		data->pdata.pnfs_error = 0;
-		return pnfs_readpages(data);
-	}
+	dprintk("%s: Utilizing pNFS I/O\n", __func__);
+	data->pdata.call_ops = call_ops;
+	data->pdata.pnfs_error = 0;
+	return pnfs_readpages(data);
 }
 
 enum pnfs_try_status
diff --git a/fs/nfs/pnfs.h b/fs/nfs/pnfs.h
index 242abf5..5201973 100644
--- a/fs/nfs/pnfs.h
+++ b/fs/nfs/pnfs.h
@@ -93,22 +93,29 @@ static inline int pnfs_enabled_sb(struct nfs_server *nfss)
 	return nfss->pnfs_curr_ld != NULL;
 }
 
+static inline void _pnfs_clear_lseg_from_pages(struct list_head *head)
+{
+	struct nfs_page *req;
+
+	list_for_each_entry(req, head, wb_list) {
+		put_lseg(req->wb_lseg);
+		req->wb_lseg = NULL;
+	}
+}
+
 static inline enum pnfs_try_status
 pnfs_try_to_read_data(struct nfs_read_data *data,
 		      const struct rpc_call_ops *call_ops)
 {
-	struct inode *inode = data->inode;
-	struct nfs_server *nfss = NFS_SERVER(inode);
 	enum pnfs_try_status ret;
 
-	/* FIXME: read_pagelist should probably be mandated */
-	if (PNFS_EXISTS_LDIO_OP(nfss, read_pagelist))
-		ret = _pnfs_try_to_read_data(data, call_ops);
-	else
-		ret = PNFS_NOT_ATTEMPTED;
-
+	if (!data->req->wb_lseg)
+		return PNFS_NOT_ATTEMPTED;
+	ret = _pnfs_try_to_read_data(data, call_ops);
 	if (ret == PNFS_ATTEMPTED)
-		nfs_inc_stats(inode, NFSIOS_PNFS_READ);
+		nfs_inc_stats(data->inode, NFSIOS_PNFS_READ);
+	else
+		_pnfs_clear_lseg_from_pages(&data->pages);
 	return ret;
 }
 
-- 
1.6.6.1