NFSv4.1: define nfs_generic_pg_test

By default, unless pnfs is used coalesce pages until pg_bsize
(rsize or wsize) is reached.

pnfs layout drivers define their own pg_test methods that use
pnfs_generic_pg_test and need to define their own I/O size
limits (e.g. based on the file stripe size).

[Move a check from nfs_pageio_do_add_request to nfs_generic_pg_test]
Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: Benny Halevy <bhalevy@panasas.com>

diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c
index 5344371a257cff4becbf73603b2bba73194bd34c..7913961aff225995fda011973ed048276ae826e9 100644 (file)
--- a/fs/nfs/pagelist.c
+++ b/fs/nfs/pagelist.c
@@ -204,6 +204,21 @@ nfs_wait_on_request(struct nfs_page *req)
                        TASK_UNINTERRUPTIBLE);
 }
 
+static bool nfs_generic_pg_test(struct nfs_pageio_descriptor *desc, struct nfs_page *prev, struct nfs_page *req)
+{
+       /*
+        * FIXME: ideally we should be able to coalesce all requests
+        * that are not block boundary aligned, but currently this
+        * is problematic for the case of bsize < PAGE_CACHE_SIZE,
+        * since nfs_flush_multi and nfs_pagein_multi assume you
+        * can have only one struct nfs_page.
+        */
+       if (desc->pg_bsize < PAGE_SIZE)
+               return 0;
+
+       return desc->pg_count + req->wb_bytes <= desc->pg_bsize;
+}
+
 /**
  * nfs_pageio_init - initialise a page io descriptor
  * @desc: pointer to descriptor
@@ -229,7 +244,7 @@ void nfs_pageio_init(struct nfs_pageio_descriptor *desc,
        desc->pg_ioflags = io_flags;
        desc->pg_error = 0;
        desc->pg_lseg = NULL;
-       desc->pg_test = NULL;
+       desc->pg_test = nfs_generic_pg_test;
        pnfs_pageio_init(desc, inode);
 }
 
@@ -260,13 +275,7 @@ static bool nfs_can_coalesce_requests(struct nfs_page *prev,
                return false;
        if (prev->wb_pgbase + prev->wb_bytes != PAGE_CACHE_SIZE)
                return false;
-       /*
-        * Non-whole file layouts need to check that req is inside of
-        * pgio->pg_lseg.
-        */
-       if (pgio->pg_test && !pgio->pg_test(pgio, prev, req))
-               return false;
-       return true;
+       return pgio->pg_test(pgio, prev, req);
 }
 
 /**
@@ -280,31 +289,18 @@ static bool nfs_can_coalesce_requests(struct nfs_page *prev,
 static int nfs_pageio_do_add_request(struct nfs_pageio_descriptor *desc,
                                     struct nfs_page *req)
 {
-       size_t newlen = req->wb_bytes;
-
        if (desc->pg_count != 0) {
                struct nfs_page *prev;
 
-               /*
-                * FIXME: ideally we should be able to coalesce all requests
-                * that are not block boundary aligned, but currently this
-                * is problematic for the case of bsize < PAGE_CACHE_SIZE,
-                * since nfs_flush_multi and nfs_pagein_multi assume you
-                * can have only one struct nfs_page.
-                */
-               if (desc->pg_bsize < PAGE_SIZE)
-                       return 0;
-               newlen += desc->pg_count;
-               if (newlen > desc->pg_bsize)
-                       return 0;
                prev = nfs_list_entry(desc->pg_list.prev);
                if (!nfs_can_coalesce_requests(prev, req, desc))
                        return 0;
-       } else
+       } else {
                desc->pg_base = req->wb_pgbase;
+       }
        nfs_list_remove_request(req);
        nfs_list_add_request(req, &desc->pg_list);
-       desc->pg_count = newlen;
+       desc->pg_count += req->wb_bytes;
        return 1;
 }