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
nilfs_sync_file(struct file * file,loff_t start,loff_t end,int datasync)16 int 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
nilfs_page_mkwrite(struct vm_fault * vmf)45 static vm_fault_t nilfs_page_mkwrite(struct vm_fault *vmf)
46 {
47 struct vm_area_struct *vma = vmf->vma;
48 struct page *page = vmf->page;
49 struct inode *inode = file_inode(vma->vm_file);
50 struct nilfs_transaction_info ti;
51 int ret = 0;
52
53 if (unlikely(nilfs_near_disk_full(inode->i_sb->s_fs_info)))
54 return VM_FAULT_SIGBUS; /* -ENOSPC */
55
56 sb_start_pagefault(inode->i_sb);
57 lock_page(page);
58 if (page->mapping != inode->i_mapping ||
59 page_offset(page) >= i_size_read(inode) || !PageUptodate(page)) {
60 unlock_page(page);
61 ret = -EFAULT; /* make the VM retry the fault */
62 goto out;
63 }
64
65 /*
66 * check to see if the page is mapped already (no holes)
67 */
68 if (PageMappedToDisk(page))
69 goto mapped;
70
71 if (page_has_buffers(page)) {
72 struct buffer_head *bh, *head;
73 int fully_mapped = 1;
74
75 bh = head = page_buffers(page);
76 do {
77 if (!buffer_mapped(bh)) {
78 fully_mapped = 0;
79 break;
80 }
81 } while (bh = bh->b_this_page, bh != head);
82
83 if (fully_mapped) {
84 SetPageMappedToDisk(page);
85 goto mapped;
86 }
87 }
88 unlock_page(page);
89
90 /*
91 * fill hole blocks
92 */
93 ret = nilfs_transaction_begin(inode->i_sb, &ti, 1);
94 /* never returns -ENOMEM, but may return -ENOSPC */
95 if (unlikely(ret))
96 goto out;
97
98 file_update_time(vma->vm_file);
99 ret = block_page_mkwrite(vma, vmf, nilfs_get_block);
100 if (ret) {
101 nilfs_transaction_abort(inode->i_sb);
102 goto out;
103 }
104 nilfs_set_file_dirty(inode, 1 << (PAGE_SHIFT - inode->i_blkbits));
105 nilfs_transaction_commit(inode->i_sb);
106
107 mapped:
108 /*
109 * Since checksumming including data blocks is performed to determine
110 * the validity of the log to be written and used for recovery, it is
111 * necessary to wait for writeback to finish here, regardless of the
112 * stable write requirement of the backing device.
113 */
114 wait_on_page_writeback(page);
115 out:
116 sb_end_pagefault(inode->i_sb);
117 return vmf_fs_error(ret);
118 }
119
120 static const struct vm_operations_struct nilfs_file_vm_ops = {
121 .fault = filemap_fault,
122 .map_pages = filemap_map_pages,
123 .page_mkwrite = nilfs_page_mkwrite,
124 };
125
nilfs_file_mmap(struct file * file,struct vm_area_struct * vma)126 static int nilfs_file_mmap(struct file *file, struct vm_area_struct *vma)
127 {
128 file_accessed(file);
129 vma->vm_ops = &nilfs_file_vm_ops;
130 return 0;
131 }
132
133 /*
134 * We have mostly NULL's here: the current defaults are ok for
135 * the nilfs filesystem.
136 */
137 const struct file_operations nilfs_file_operations = {
138 .llseek = generic_file_llseek,
139 .read_iter = generic_file_read_iter,
140 .write_iter = generic_file_write_iter,
141 .unlocked_ioctl = nilfs_ioctl,
142 #ifdef CONFIG_COMPAT
143 .compat_ioctl = nilfs_compat_ioctl,
144 #endif /* CONFIG_COMPAT */
145 .mmap = nilfs_file_mmap,
146 .open = generic_file_open,
147 /* .release = nilfs_release_file, */
148 .fsync = nilfs_sync_file,
149 .splice_read = filemap_splice_read,
150 .splice_write = iter_file_splice_write,
151 };
152
153 const struct inode_operations nilfs_file_inode_operations = {
154 .setattr = nilfs_setattr,
155 .permission = nilfs_permission,
156 .fiemap = nilfs_fiemap,
157 .fileattr_get = nilfs_fileattr_get,
158 .fileattr_set = nilfs_fileattr_set,
159 };
160
161 /* end of file */
162