1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * NILFS regular file handling primitives including fsync().
4 *
5 * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
6 *
7 * Written by Amagai Yoshiji and Ryusuke Konishi.
8 */
9
10#include <linux/fs.h>
11#include <linux/mm.h>
12#include <linux/writeback.h>
13#include "nilfs.h"
14#include "segment.h"
15
16int nilfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
17{
18	/*
19	 * Called from fsync() system call
20	 * This is the only entry point that can catch write and synch
21	 * timing for both data blocks and intermediate blocks.
22	 *
23	 * This function should be implemented when the writeback function
24	 * will be implemented.
25	 */
26	struct the_nilfs *nilfs;
27	struct inode *inode = file->f_mapping->host;
28	int err = 0;
29
30	if (nilfs_inode_dirty(inode)) {
31		if (datasync)
32			err = nilfs_construct_dsync_segment(inode->i_sb, inode,
33							    start, end);
34		else
35			err = nilfs_construct_segment(inode->i_sb);
36	}
37
38	nilfs = inode->i_sb->s_fs_info;
39	if (!err)
40		err = nilfs_flush_device(nilfs);
41
42	return err;
43}
44
45static vm_fault_t nilfs_page_mkwrite(struct vm_fault *vmf)
46{
47	struct vm_area_struct *vma = vmf->vma;
48	struct folio *folio = page_folio(vmf->page);
49	struct inode *inode = file_inode(vma->vm_file);
50	struct nilfs_transaction_info ti;
51	struct buffer_head *bh, *head;
52	int ret = 0;
53
54	if (unlikely(nilfs_near_disk_full(inode->i_sb->s_fs_info)))
55		return VM_FAULT_SIGBUS; /* -ENOSPC */
56
57	sb_start_pagefault(inode->i_sb);
58	folio_lock(folio);
59	if (folio->mapping != inode->i_mapping ||
60	    folio_pos(folio) >= i_size_read(inode) ||
61	    !folio_test_uptodate(folio)) {
62		folio_unlock(folio);
63		ret = -EFAULT;	/* make the VM retry the fault */
64		goto out;
65	}
66
67	/*
68	 * check to see if the folio is mapped already (no holes)
69	 */
70	if (folio_test_mappedtodisk(folio))
71		goto mapped;
72
73	head = folio_buffers(folio);
74	if (head) {
75		int fully_mapped = 1;
76
77		bh = head;
78		do {
79			if (!buffer_mapped(bh)) {
80				fully_mapped = 0;
81				break;
82			}
83		} while (bh = bh->b_this_page, bh != head);
84
85		if (fully_mapped) {
86			folio_set_mappedtodisk(folio);
87			goto mapped;
88		}
89	}
90	folio_unlock(folio);
91
92	/*
93	 * fill hole blocks
94	 */
95	ret = nilfs_transaction_begin(inode->i_sb, &ti, 1);
96	/* never returns -ENOMEM, but may return -ENOSPC */
97	if (unlikely(ret))
98		goto out;
99
100	file_update_time(vma->vm_file);
101	ret = block_page_mkwrite(vma, vmf, nilfs_get_block);
102	if (ret) {
103		nilfs_transaction_abort(inode->i_sb);
104		goto out;
105	}
106	nilfs_set_file_dirty(inode, 1 << (PAGE_SHIFT - inode->i_blkbits));
107	nilfs_transaction_commit(inode->i_sb);
108
109 mapped:
110	/*
111	 * Since checksumming including data blocks is performed to determine
112	 * the validity of the log to be written and used for recovery, it is
113	 * necessary to wait for writeback to finish here, regardless of the
114	 * stable write requirement of the backing device.
115	 */
116	folio_wait_writeback(folio);
117 out:
118	sb_end_pagefault(inode->i_sb);
119	return vmf_fs_error(ret);
120}
121
122static const struct vm_operations_struct nilfs_file_vm_ops = {
123	.fault		= filemap_fault,
124	.map_pages	= filemap_map_pages,
125	.page_mkwrite	= nilfs_page_mkwrite,
126};
127
128static int nilfs_file_mmap(struct file *file, struct vm_area_struct *vma)
129{
130	file_accessed(file);
131	vma->vm_ops = &nilfs_file_vm_ops;
132	return 0;
133}
134
135/*
136 * We have mostly NULL's here: the current defaults are ok for
137 * the nilfs filesystem.
138 */
139const struct file_operations nilfs_file_operations = {
140	.llseek		= generic_file_llseek,
141	.read_iter	= generic_file_read_iter,
142	.write_iter	= generic_file_write_iter,
143	.unlocked_ioctl	= nilfs_ioctl,
144#ifdef CONFIG_COMPAT
145	.compat_ioctl	= nilfs_compat_ioctl,
146#endif	/* CONFIG_COMPAT */
147	.mmap		= nilfs_file_mmap,
148	.open		= generic_file_open,
149	/* .release	= nilfs_release_file, */
150	.fsync		= nilfs_sync_file,
151	.splice_read	= filemap_splice_read,
152	.splice_write   = iter_file_splice_write,
153};
154
155const struct inode_operations nilfs_file_inode_operations = {
156	.setattr	= nilfs_setattr,
157	.permission     = nilfs_permission,
158	.fiemap		= nilfs_fiemap,
159	.fileattr_get	= nilfs_fileattr_get,
160	.fileattr_set	= nilfs_fileattr_set,
161};
162
163/* end of file */
164