fs: cachefiles: add support for large files in filesystem caching

commit 98c350c upstream.

Support the caching of large files.

Addresses https://bugzilla.kernel.org/show_bug.cgi?id=31182

Signed-off-by: Justin Lecher <jlec@gentoo.org>
Signed-off-by: Suresh Jayaraman <sjayaraman@suse.com>
Tested-by: Suresh Jayaraman <sjayaraman@suse.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[bwh: Backported to 3.2:
 - Adjust context
 - dentry_open() takes dentry and vfsmount pointers, not a path pointer]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

fs/cachefiles/rdwr.c

@@ -918,7 +918,7 @@ int cachefiles_write_page(struct fscache_storage *op, struct page *page)
 	 * own time */
 	dget(object->backer);
 	mntget(cache->mnt);
-	file = dentry_open(object->backer, cache->mnt, O_RDWR,
+	file = dentry_open(object->backer, cache->mnt, O_RDWR | O_LARGEFILE,
 			   cache->cache_cred);
 	if (IS_ERR(file)) {
 		ret = PTR_ERR(file);