1/*
2 * file.c - NILFS regular file handling primitives including fsync().
3 *
4 * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
19 *
20 * Written by Amagai Yoshiji <amagai@osrg.net>,
21 *            Ryusuke Konishi <ryusuke@osrg.net>
22 */
23
24#include <linux/fs.h>
25#include <linux/mm.h>
26#include <linux/writeback.h>
27#include "nilfs.h"
28#include "segment.h"
29
30int nilfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
31{
32	/*
33	 * Called from fsync() system call
34	 * This is the only entry point that can catch write and synch
35	 * timing for both data blocks and intermediate blocks.
36	 *
37	 * This function should be implemented when the writeback function
38	 * will be implemented.
39	 */
40	struct the_nilfs *nilfs;
41	struct inode *inode = file->f_mapping->host;
42	int err = 0;
43
44	if (nilfs_inode_dirty(inode)) {
45		if (datasync)
46			err = nilfs_construct_dsync_segment(inode->i_sb, inode,
47							    start, end);
48		else
49			err = nilfs_construct_segment(inode->i_sb);
50	}
51
52	nilfs = inode->i_sb->s_fs_info;
53	if (!err)
54		err = nilfs_flush_device(nilfs);
55
56	return err;
57}
58
59static int nilfs_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
60{
61	struct page *page = vmf->page;
62	struct inode *inode = file_inode(vma->vm_file);
63	struct nilfs_transaction_info ti;
64	int ret = 0;
65
66	if (unlikely(nilfs_near_disk_full(inode->i_sb->s_fs_info)))
67		return VM_FAULT_SIGBUS; /* -ENOSPC */
68
69	sb_start_pagefault(inode->i_sb);
70	lock_page(page);
71	if (page->mapping != inode->i_mapping ||
72	    page_offset(page) >= i_size_read(inode) || !PageUptodate(page)) {
73		unlock_page(page);
74		ret = -EFAULT;	/* make the VM retry the fault */
75		goto out;
76	}
77
78	/*
79	 * check to see if the page is mapped already (no holes)
80	 */
81	if (PageMappedToDisk(page))
82		goto mapped;
83
84	if (page_has_buffers(page)) {
85		struct buffer_head *bh, *head;
86		int fully_mapped = 1;
87
88		bh = head = page_buffers(page);
89		do {
90			if (!buffer_mapped(bh)) {
91				fully_mapped = 0;
92				break;
93			}
94		} while (bh = bh->b_this_page, bh != head);
95
96		if (fully_mapped) {
97			SetPageMappedToDisk(page);
98			goto mapped;
99		}
100	}
101	unlock_page(page);
102
103	/*
104	 * fill hole blocks
105	 */
106	ret = nilfs_transaction_begin(inode->i_sb, &ti, 1);
107	/* never returns -ENOMEM, but may return -ENOSPC */
108	if (unlikely(ret))
109		goto out;
110
111	file_update_time(vma->vm_file);
112	ret = __block_page_mkwrite(vma, vmf, nilfs_get_block);
113	if (ret) {
114		nilfs_transaction_abort(inode->i_sb);
115		goto out;
116	}
117	nilfs_set_file_dirty(inode, 1 << (PAGE_SHIFT - inode->i_blkbits));
118	nilfs_transaction_commit(inode->i_sb);
119
120 mapped:
121	wait_for_stable_page(page);
122 out:
123	sb_end_pagefault(inode->i_sb);
124	return block_page_mkwrite_return(ret);
125}
126
127static const struct vm_operations_struct nilfs_file_vm_ops = {
128	.fault		= filemap_fault,
129	.map_pages	= filemap_map_pages,
130	.page_mkwrite	= nilfs_page_mkwrite,
131};
132
133static int nilfs_file_mmap(struct file *file, struct vm_area_struct *vma)
134{
135	file_accessed(file);
136	vma->vm_ops = &nilfs_file_vm_ops;
137	return 0;
138}
139
140/*
141 * We have mostly NULL's here: the current defaults are ok for
142 * the nilfs filesystem.
143 */
144const struct file_operations nilfs_file_operations = {
145	.llseek		= generic_file_llseek,
146	.read_iter	= generic_file_read_iter,
147	.write_iter	= generic_file_write_iter,
148	.unlocked_ioctl	= nilfs_ioctl,
149#ifdef CONFIG_COMPAT
150	.compat_ioctl	= nilfs_compat_ioctl,
151#endif	/* CONFIG_COMPAT */
152	.mmap		= nilfs_file_mmap,
153	.open		= generic_file_open,
154	/* .release	= nilfs_release_file, */
155	.fsync		= nilfs_sync_file,
156	.splice_read	= generic_file_splice_read,
157};
158
159const struct inode_operations nilfs_file_inode_operations = {
160	.setattr	= nilfs_setattr,
161	.permission     = nilfs_permission,
162	.fiemap		= nilfs_fiemap,
163};
164
165/* end of file */
166