GNU Linux-libre 4.19.211-gnu1
[releases.git] / fs / nilfs2 / file.c
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * file.c - 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
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
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         wait_for_stable_page(page);
109  out:
110         sb_end_pagefault(inode->i_sb);
111         return block_page_mkwrite_return(ret);
112 }
113
114 static const struct vm_operations_struct nilfs_file_vm_ops = {
115         .fault          = filemap_fault,
116         .map_pages      = filemap_map_pages,
117         .page_mkwrite   = nilfs_page_mkwrite,
118 };
119
120 static int nilfs_file_mmap(struct file *file, struct vm_area_struct *vma)
121 {
122         file_accessed(file);
123         vma->vm_ops = &nilfs_file_vm_ops;
124         return 0;
125 }
126
127 /*
128  * We have mostly NULL's here: the current defaults are ok for
129  * the nilfs filesystem.
130  */
131 const struct file_operations nilfs_file_operations = {
132         .llseek         = generic_file_llseek,
133         .read_iter      = generic_file_read_iter,
134         .write_iter     = generic_file_write_iter,
135         .unlocked_ioctl = nilfs_ioctl,
136 #ifdef CONFIG_COMPAT
137         .compat_ioctl   = nilfs_compat_ioctl,
138 #endif  /* CONFIG_COMPAT */
139         .mmap           = nilfs_file_mmap,
140         .open           = generic_file_open,
141         /* .release     = nilfs_release_file, */
142         .fsync          = nilfs_sync_file,
143         .splice_read    = generic_file_splice_read,
144 };
145
146 const struct inode_operations nilfs_file_inode_operations = {
147         .setattr        = nilfs_setattr,
148         .permission     = nilfs_permission,
149         .fiemap         = nilfs_fiemap,
150 };
151
152 /* end of file */