NFS: Move the pnfs read code into pnfs.c

...and ensure that we recoalese to take into account differences in
block sizes when falling back to read through the MDS.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 55 insertions, 2 deletions

diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
index 5b3cc3f4bb39..9eca5a8cdbdd 100644
--- a/fs/nfs/pnfs.c
+++ b/fs/nfs/pnfs.c
@@ -28,6 +28,7 @@
  */
 
 #include <linux/nfs_fs.h>
+#include <linux/nfs_page.h>
 #include "internal.h"
 #include "pnfs.h"
 #include "iostat.h"
@@ -1216,18 +1217,32 @@ pnfs_ld_read_done(struct nfs_read_data *data)
 }
 EXPORT_SYMBOL_GPL(pnfs_ld_read_done);
 
+static void
+pnfs_read_through_mds(struct nfs_pageio_descriptor *desc,
+                struct nfs_read_data *data)
+{
+        list_splice_tail_init(&data->pages, &desc->pg_list);
+        if (data->req && list_empty(&data->req->wb_list))
+                nfs_list_add_request(data->req, &desc->pg_list);
+        nfs_pageio_reset_read_mds(desc);
+        desc->pg_recoalesce = 1;
+        nfs_readdata_release(data);
+}
+
 /*
  * Call the appropriate parallel I/O subsystem read function.
  */
-enum pnfs_try_status
+static enum pnfs_try_status
 pnfs_try_to_read_data(struct nfs_read_data *rdata,
-                       const struct rpc_call_ops *call_ops)
+                       const struct rpc_call_ops *call_ops,
+                       struct pnfs_layout_segment *lseg)
 {
         struct inode *inode = rdata->inode;
         struct nfs_server *nfss = NFS_SERVER(inode);
         enum pnfs_try_status trypnfs;
 
         rdata->mds_ops = call_ops;
+        rdata->lseg = get_lseg(lseg);
 
         dprintk("%s: Reading ino:%lu %u@%llu\n",
                 __func__, inode->i_ino, rdata->args.count, rdata->args.offset);
@@ -1243,6 +1258,44 @@ pnfs_try_to_read_data(struct nfs_read_data *rdata,
         return trypnfs;
 }
 
+static void
+pnfs_do_multiple_reads(struct nfs_pageio_descriptor *desc, struct list_head *head)
+{
+        struct nfs_read_data *data;
+        const struct rpc_call_ops *call_ops = desc->pg_rpc_callops;
+        struct pnfs_layout_segment *lseg = desc->pg_lseg;
+
+        desc->pg_lseg = NULL;
+        while (!list_empty(head)) {
+                enum pnfs_try_status trypnfs;
+
+                data = list_entry(head->next, struct nfs_read_data, list);
+                list_del_init(&data->list);
+
+                trypnfs = pnfs_try_to_read_data(data, call_ops, lseg);
+                if (trypnfs == PNFS_NOT_ATTEMPTED)
+                        pnfs_read_through_mds(desc, data);
+        }
+        put_lseg(lseg);
+}
+
+int
+pnfs_generic_pg_readpages(struct nfs_pageio_descriptor *desc)
+{
+        LIST_HEAD(head);
+        int ret;
+
+        ret = nfs_generic_pagein(desc, &head);
+        if (ret != 0) {
+                put_lseg(desc->pg_lseg);
+                desc->pg_lseg = NULL;
+                return ret;
+        }
+        pnfs_do_multiple_reads(desc, &head);
+        return 0;
+}
+EXPORT_SYMBOL_GPL(pnfs_generic_pg_readpages);
+
 /*
  * Currently there is only one (whole file) write lseg.
  */