From: David Howells <dhowells@redhat.com>

The attached patch makes the kAFS filesystem in fs/afs/ use FS-Cache, and
through it any attached caches.  The kAFS filesystem will use caching
automatically if it's available.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---

 fs/afs/file.c  |   60 +++++++++++++++++++++--------------------------
 fs/afs/vnode.c |    2 +
 2 files changed, 30 insertions(+), 32 deletions(-)

diff -puN fs/afs/file.c~fs-cache-make-kafs-use-fs-cache-12 fs/afs/file.c
--- a/fs/afs/file.c~fs-cache-make-kafs-use-fs-cache-12
+++ a/fs/afs/file.c
@@ -83,7 +83,7 @@ static int afs_file_mmap(struct file *fi
 	file_accessed(file);
 	vma->vm_ops = &afs_fs_vm_operations;
 	return 0;
-} /* end afs_file_mmap() */
+}
 
 /*****************************************************************************/
 /*
@@ -101,8 +101,7 @@ static void afs_file_readpage_read_compl
 	if (!error)
 		SetPageUptodate(page);
 	unlock_page(page);
-
-} /* end afs_file_readpage_read_complete() */
+}
 #endif
 
 /*****************************************************************************/
@@ -119,8 +118,7 @@ static void afs_file_readpage_write_comp
 	/* note that the page has been written to the cache and can now be
 	 * modified */
 	end_page_fs_misc(page);
-
-} /* end afs_file_readpage_write_complete() */
+}
 #endif
 
 /*****************************************************************************/
@@ -230,8 +228,7 @@ static int afs_file_readpage(struct file
 
 	_leave(" = %d", ret);
 	return ret;
-
-} /* end afs_file_readpage() */
+}
 
 /*****************************************************************************/
 /*
@@ -242,10 +239,6 @@ static int afs_file_readpages(struct fil
 			      struct list_head *pages, unsigned nr_pages)
 {
 	struct afs_vnode *vnode;
-#if 0
-	struct pagevec lru_pvec;
-	unsigned page_idx;
-#endif
 	int ret = 0;
 
 	_enter(",{%lu},,%d", mapping->host->i_ino, nr_pages);
@@ -290,13 +283,14 @@ static int afs_file_readpages(struct fil
 
 	_leave(" = %d [netting]", ret);
 	return ret;
-
-} /* end afs_file_readpages() */
+}
 #endif
 
 /*****************************************************************************/
 /*
  * invalidate part or all of a page
+ * - release a page and clean up its private data if offset is 0 (indicating
+ *   the entire page)
  */
 static void afs_file_invalidatepage(struct page *page, unsigned long offset)
 {
@@ -305,38 +299,41 @@ static void afs_file_invalidatepage(stru
 	BUG_ON(!PageLocked(page));
 
 	if (PagePrivate(page)) {
-		/* We release buffers only if the entire page is being
-		 * invalidated.
-		 * The get_block cached value has been unconditionally
-		 * invalidated, so real IO is not possible anymore.
-		 */
-		if (offset == 0 && !PageWriteback(page))
-			page->mapping->a_ops->releasepage(page, 0);
+		/* we clean up only if the entire page is being invalidated */
+		if (offset == 0 && !PageWriteback(page)) {
+#ifdef CONFIG_AFS_FSCACHE
+			wait_on_page_fs_misc(page);
+			fscache_uncache_page(
+				AFS_FS_I(page->mapping->host)->cache, page);
+			ClearPagePrivate(page);
+#endif
+		}
 	}
 
 	_leave("");
-
-} /* end afs_file_invalidatepage() */
+}
 
 /*****************************************************************************/
 /*
- * release a page and cleanup its private data
+ * release a page and clean up its private state if it's not busy
+ * - return true if the page can now be released, false if not
  */
 static int afs_file_releasepage(struct page *page, gfp_t gfp_flags)
 {
 	_enter("{%lu},%x", page->index, gfp_flags);
 
-#ifdef CONFIG_AFS_FSCACHE
-	wait_on_page_fs_misc(page);
+	/* deny */
+	if (PageFsMisc(page)) {
+		_leave(" = F");
+		return 0;
+	}
+
 	fscache_uncache_page(AFS_FS_I(page->mapping->host)->cache, page);
-	ClearPagePrivate(page);
-#endif
 
 	/* indicate that the page can be released */
-	_leave(" = 1");
+	_leave(" = T");
 	return 1;
-
-} /* end afs_file_releasepage() */
+}
 
 /*****************************************************************************/
 /*
@@ -348,6 +345,5 @@ static int afs_file_page_mkwrite(struct 
 {
 	wait_on_page_fs_misc(page);
 	return 0;
-
-} /* end afs_file_page_mkwrite() */
+}
 #endif
diff -puN fs/afs/vnode.c~fs-cache-make-kafs-use-fs-cache-12 fs/afs/vnode.c
--- a/fs/afs/vnode.c~fs-cache-make-kafs-use-fs-cache-12
+++ a/fs/afs/vnode.c
@@ -508,6 +508,7 @@ static void afs_vnode_cache_mark_pages_c
 	}
 
 } /* end afs_vnode_cache_mark_pages_cached() */
+#endif
 
 /*****************************************************************************/
 /*
@@ -517,6 +518,7 @@ static void afs_vnode_cache_mark_pages_c
  * - the netfs should use this to clean up any markers indicating cached pages
  * - this is mandatory for any object that may have data
  */
+#ifdef CONFIG_AFS_FSCACHE
 static void afs_vnode_cache_now_uncached(void *cookie_netfs_data)
 {
 	struct afs_vnode *vnode = cookie_netfs_data;
_