xref: /openbmc/linux/fs/nilfs2/file.c (revision 4800cd83)
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 
30 int nilfs_sync_file(struct file *file, 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 inode *inode = file->f_mapping->host;
41 	int err;
42 
43 	if (!nilfs_inode_dirty(inode))
44 		return 0;
45 
46 	if (datasync)
47 		err = nilfs_construct_dsync_segment(inode->i_sb, inode, 0,
48 						    LLONG_MAX);
49 	else
50 		err = nilfs_construct_segment(inode->i_sb);
51 
52 	return err;
53 }
54 
55 static int nilfs_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
56 {
57 	struct page *page = vmf->page;
58 	struct inode *inode = vma->vm_file->f_dentry->d_inode;
59 	struct nilfs_transaction_info ti;
60 	int ret;
61 
62 	if (unlikely(nilfs_near_disk_full(NILFS_SB(inode->i_sb)->s_nilfs)))
63 		return VM_FAULT_SIGBUS; /* -ENOSPC */
64 
65 	lock_page(page);
66 	if (page->mapping != inode->i_mapping ||
67 	    page_offset(page) >= i_size_read(inode) || !PageUptodate(page)) {
68 		unlock_page(page);
69 		return VM_FAULT_NOPAGE; /* make the VM retry the fault */
70 	}
71 
72 	/*
73 	 * check to see if the page is mapped already (no holes)
74 	 */
75 	if (PageMappedToDisk(page)) {
76 		unlock_page(page);
77 		goto mapped;
78 	}
79 	if (page_has_buffers(page)) {
80 		struct buffer_head *bh, *head;
81 		int fully_mapped = 1;
82 
83 		bh = head = page_buffers(page);
84 		do {
85 			if (!buffer_mapped(bh)) {
86 				fully_mapped = 0;
87 				break;
88 			}
89 		} while (bh = bh->b_this_page, bh != head);
90 
91 		if (fully_mapped) {
92 			SetPageMappedToDisk(page);
93 			unlock_page(page);
94 			goto mapped;
95 		}
96 	}
97 	unlock_page(page);
98 
99 	/*
100 	 * fill hole blocks
101 	 */
102 	ret = nilfs_transaction_begin(inode->i_sb, &ti, 1);
103 	/* never returns -ENOMEM, but may return -ENOSPC */
104 	if (unlikely(ret))
105 		return VM_FAULT_SIGBUS;
106 
107 	ret = block_page_mkwrite(vma, vmf, nilfs_get_block);
108 	if (unlikely(ret)) {
109 		nilfs_transaction_abort(inode->i_sb);
110 		return ret;
111 	}
112 	nilfs_transaction_commit(inode->i_sb);
113 
114  mapped:
115 	SetPageChecked(page);
116 	wait_on_page_writeback(page);
117 	return 0;
118 }
119 
120 static const struct vm_operations_struct nilfs_file_vm_ops = {
121 	.fault		= filemap_fault,
122 	.page_mkwrite	= nilfs_page_mkwrite,
123 };
124 
125 static int nilfs_file_mmap(struct file *file, struct vm_area_struct *vma)
126 {
127 	file_accessed(file);
128 	vma->vm_ops = &nilfs_file_vm_ops;
129 	vma->vm_flags |= VM_CAN_NONLINEAR;
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		= do_sync_read,
140 	.write		= do_sync_write,
141 	.aio_read	= generic_file_aio_read,
142 	.aio_write	= generic_file_aio_write,
143 	.unlocked_ioctl	= nilfs_ioctl,
144 #ifdef CONFIG_COMPAT
145 	.compat_ioctl	= nilfs_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	= generic_file_splice_read,
152 };
153 
154 const struct inode_operations nilfs_file_inode_operations = {
155 	.truncate	= nilfs_truncate,
156 	.setattr	= nilfs_setattr,
157 	.permission     = nilfs_permission,
158 	.fiemap		= nilfs_fiemap,
159 };
160 
161 /* end of file */
162