ANDROID: Included sdcardfs source code for kernel 3.0
Only included the source code as is for kernel 3.0. Following patches
take care of porting this file system to version 3.10.
Change-Id: I09e76db77cd98a059053ba5b6fd88572a4b75b5b
Signed-off-by: Daniel Campello <campello@google.com>
diff --git a/fs/sdcardfs/mmap.c b/fs/sdcardfs/mmap.c
new file mode 100644
index 0000000..c807d7f
--- /dev/null
+++ b/fs/sdcardfs/mmap.c
@@ -0,0 +1,82 @@
+/*
+ * fs/sdcardfs/mmap.c
+ *
+ * Copyright (c) 2013 Samsung Electronics Co. Ltd
+ * Authors: Daeho Jeong, Woojoong Lee, Seunghwan Hyun,
+ * Sunghwan Yun, Sungjong Seo
+ *
+ * This program has been developed as a stackable file system based on
+ * the WrapFS which written by
+ *
+ * Copyright (c) 1998-2011 Erez Zadok
+ * Copyright (c) 2009 Shrikar Archak
+ * Copyright (c) 2003-2011 Stony Brook University
+ * Copyright (c) 2003-2011 The Research Foundation of SUNY
+ *
+ * This file is dual licensed. It may be redistributed and/or modified
+ * under the terms of the Apache 2.0 License OR version 2 of the GNU
+ * General Public License.
+ */
+
+#include "sdcardfs.h"
+
+static int sdcardfs_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
+{
+ int err;
+ struct file *file, *lower_file;
+ const struct vm_operations_struct *lower_vm_ops;
+ struct vm_area_struct lower_vma;
+
+ memcpy(&lower_vma, vma, sizeof(struct vm_area_struct));
+ file = lower_vma.vm_file;
+ lower_vm_ops = SDCARDFS_F(file)->lower_vm_ops;
+ BUG_ON(!lower_vm_ops);
+
+ lower_file = sdcardfs_lower_file(file);
+ /*
+ * XXX: vm_ops->fault may be called in parallel. Because we have to
+ * resort to temporarily changing the vma->vm_file to point to the
+ * lower file, a concurrent invocation of sdcardfs_fault could see a
+ * different value. In this workaround, we keep a different copy of
+ * the vma structure in our stack, so we never expose a different
+ * value of the vma->vm_file called to us, even temporarily. A
+ * better fix would be to change the calling semantics of ->fault to
+ * take an explicit file pointer.
+ */
+ lower_vma.vm_file = lower_file;
+ err = lower_vm_ops->fault(&lower_vma, vmf);
+ return err;
+}
+
+static ssize_t sdcardfs_direct_IO(int rw, struct kiocb *iocb,
+ const struct iovec *iov, loff_t offset,
+ unsigned long nr_segs)
+{
+ /*
+ * This function returns zero on purpose in order to support direct IO.
+ * __dentry_open checks a_ops->direct_IO and returns EINVAL if it is null.
+ *
+ * However, this function won't be called by certain file operations
+ * including generic fs functions. * reads and writes are delivered to
+ * the lower file systems and the direct IOs will be handled by them.
+ *
+ * NOTE: exceptionally, on the recent kernels (since Linux 3.8.x),
+ * swap_writepage invokes this function directly.
+ */
+ printk(KERN_INFO "%s, operation is not supported\n", __func__);
+ return 0;
+}
+
+/*
+ * XXX: the default address_space_ops for sdcardfs is empty. We cannot set
+ * our inode->i_mapping->a_ops to NULL because too many code paths expect
+ * the a_ops vector to be non-NULL.
+ */
+const struct address_space_operations sdcardfs_aops = {
+ /* empty on purpose */
+ .direct_IO = sdcardfs_direct_IO,
+};
+
+const struct vm_operations_struct sdcardfs_vm_ops = {
+ .fault = sdcardfs_fault,
+};