NFS: Read pages from FS-Cache into an NFS inode

Read pages from an FS-Cache data storage object representing an inode into an
NFS inode.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Steve Dickson <steved@redhat.com>
Acked-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Tested-by: Daire Byrne <Daire.Byrne@framestore.com>

1 files changed, 18 insertions, 0 deletions

diff --git a/fs/nfs/read.c b/fs/nfs/read.c
index 98b74009c9d7..e18ba792872f 100644
--- a/fs/nfs/read.c
+++ b/fs/nfs/read.c
@@ -24,6 +24,7 @@
 
 #include "internal.h"
 #include "iostat.h"
+#include "fscache.h"
 
 #define NFSDBG_FACILITY		NFSDBG_PAGECACHE
 
@@ -510,8 +511,15 @@ int nfs_readpage(struct file *file, struct page *page)
 	} else
 		ctx = get_nfs_open_context(nfs_file_open_context(file));
 
+	if (!IS_SYNC(inode)) {
+		error = nfs_readpage_from_fscache(ctx, inode, page);
+		if (error == 0)
+			goto out;
+	}
+
 	error = nfs_readpage_async(ctx, inode, page);
 
+out:
 	put_nfs_open_context(ctx);
 	return error;
 out_unlock:
@@ -584,6 +592,15 @@ int nfs_readpages(struct file *filp, struct address_space *mapping,
 			return -EBADF;
 	} else
 		desc.ctx = get_nfs_open_context(nfs_file_open_context(filp));
+
+	/* attempt to read as many of the pages as possible from the cache
+	 * - this returns -ENOBUFS immediately if the cookie is negative
+	 */
+	ret = nfs_readpages_from_fscache(desc.ctx, inode, mapping,
+					 pages, &nr_pages);
+	if (ret == 0)
+		goto read_complete; /* all pages were read */
+
 	if (rsize < PAGE_CACHE_SIZE)
 		nfs_pageio_init(&pgio, inode, nfs_pagein_multi, rsize, 0);
 	else
@@ -594,6 +611,7 @@ int nfs_readpages(struct file *filp, struct address_space *mapping,
 	nfs_pageio_complete(&pgio);
 	npages = (pgio.pg_bytes_written + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
 	nfs_add_stats(inode, NFSIOS_READPAGES, npages);
+read_complete:
 	put_nfs_open_context(desc.ctx);
 out:
 	return ret;