Fixed MTP to work with TWRP

fs/nilfs2/file.c

@@ -0,0 +1,174 @@
+/*
+ * file.c - NILFS regular file handling primitives including fsync().
+ *
+ * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ * Written by Amagai Yoshiji <amagai@osrg.net>,
+ *            Ryusuke Konishi <ryusuke@osrg.net>
+ */
+
+#include <linux/fs.h>
+#include <linux/mm.h>
+#include <linux/writeback.h>
+#include "nilfs.h"
+#include "segment.h"
+
+int nilfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
+{
+	/*
+	 * Called from fsync() system call
+	 * This is the only entry point that can catch write and synch
+	 * timing for both data blocks and intermediate blocks.
+	 *
+	 * This function should be implemented when the writeback function
+	 * will be implemented.
+	 */
+	struct the_nilfs *nilfs;
+	struct inode *inode = file->f_mapping->host;
+	int err;
+
+	err = filemap_write_and_wait_range(inode->i_mapping, start, end);
+	if (err)
+		return err;
+	mutex_lock(&inode->i_mutex);
+
+	if (nilfs_inode_dirty(inode)) {
+		if (datasync)
+			err = nilfs_construct_dsync_segment(inode->i_sb, inode,
+							    0, LLONG_MAX);
+		else
+			err = nilfs_construct_segment(inode->i_sb);
+	}
+	mutex_unlock(&inode->i_mutex);
+
+	nilfs = inode->i_sb->s_fs_info;
+	if (!err)
+		err = nilfs_flush_device(nilfs);
+
+	return err;
+}
+
+static int nilfs_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
+{
+	struct page *page = vmf->page;
+	struct inode *inode = file_inode(vma->vm_file);
+	struct nilfs_transaction_info ti;
+	int ret = 0;
+
+	if (unlikely(nilfs_near_disk_full(inode->i_sb->s_fs_info)))
+		return VM_FAULT_SIGBUS; /* -ENOSPC */
+
+	sb_start_pagefault(inode->i_sb);
+	lock_page(page);
+	if (page->mapping != inode->i_mapping ||
+	    page_offset(page) >= i_size_read(inode) || !PageUptodate(page)) {
+		unlock_page(page);
+		ret = -EFAULT;	/* make the VM retry the fault */
+		goto out;
+	}
+
+	/*
+	 * check to see if the page is mapped already (no holes)
+	 */
+	if (PageMappedToDisk(page))
+		goto mapped;
+
+	if (page_has_buffers(page)) {
+		struct buffer_head *bh, *head;
+		int fully_mapped = 1;
+
+		bh = head = page_buffers(page);
+		do {
+			if (!buffer_mapped(bh)) {
+				fully_mapped = 0;
+				break;
+			}
+		} while (bh = bh->b_this_page, bh != head);
+
+		if (fully_mapped) {
+			SetPageMappedToDisk(page);
+			goto mapped;
+		}
+	}
+	unlock_page(page);
+
+	/*
+	 * fill hole blocks
+	 */
+	ret = nilfs_transaction_begin(inode->i_sb, &ti, 1);
+	/* never returns -ENOMEM, but may return -ENOSPC */
+	if (unlikely(ret))
+		goto out;
+
+	file_update_time(vma->vm_file);
+	ret = __block_page_mkwrite(vma, vmf, nilfs_get_block);
+	if (ret) {
+		nilfs_transaction_abort(inode->i_sb);
+		goto out;
+	}
+	nilfs_set_file_dirty(inode, 1 << (PAGE_SHIFT - inode->i_blkbits));
+	nilfs_transaction_commit(inode->i_sb);
+
+ mapped:
+	wait_for_stable_page(page);
+ out:
+	sb_end_pagefault(inode->i_sb);
+	return block_page_mkwrite_return(ret);
+}
+
+static const struct vm_operations_struct nilfs_file_vm_ops = {
+	.fault		= filemap_fault,
+	.map_pages	= filemap_map_pages,
+	.page_mkwrite	= nilfs_page_mkwrite,
+	.remap_pages	= generic_file_remap_pages,
+};
+
+static int nilfs_file_mmap(struct file *file, struct vm_area_struct *vma)
+{
+	file_accessed(file);
+	vma->vm_ops = &nilfs_file_vm_ops;
+	return 0;
+}
+
+/*
+ * We have mostly NULL's here: the current defaults are ok for
+ * the nilfs filesystem.
+ */
+const struct file_operations nilfs_file_operations = {
+	.llseek		= generic_file_llseek,
+	.read		= new_sync_read,
+	.write		= new_sync_write,
+	.read_iter	= generic_file_read_iter,
+	.write_iter	= generic_file_write_iter,
+	.unlocked_ioctl	= nilfs_ioctl,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl	= nilfs_compat_ioctl,
+#endif	/* CONFIG_COMPAT */
+	.mmap		= nilfs_file_mmap,
+	.open		= generic_file_open,
+	/* .release	= nilfs_release_file, */
+	.fsync		= nilfs_sync_file,
+	.splice_read	= generic_file_splice_read,
+};
+
+const struct inode_operations nilfs_file_inode_operations = {
+	.setattr	= nilfs_setattr,
+	.permission     = nilfs_permission,
+	.fiemap		= nilfs_fiemap,
+};
+
+/* end of file */