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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 block_page_mkwrite_return(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	= generic_file_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