1 /* -*- mode: c; c-basic-offset: 8; -*-
2 * vim: noexpandtab sw=8 ts=8 sts=0:
3 *
4 * mmap.c
5 *
6 * Code to deal with the mess that is clustered mmap.
7 *
8 * Copyright (C) 2002, 2004 Oracle. All rights reserved.
9 *
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public
12 * License as published by the Free Software Foundation; either
13 * version 2 of the License, or (at your option) any later version.
14 *
15 * This program is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18 * General Public License for more details.
19 *
20 * You should have received a copy of the GNU General Public
21 * License along with this program; if not, write to the
22 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
23 * Boston, MA 021110-1307, USA.
24 */
25
26 #include <linux/fs.h>
27 #include <linux/types.h>
28 #include <linux/highmem.h>
29 #include <linux/pagemap.h>
30 #include <linux/uio.h>
31 #include <linux/signal.h>
32 #include <linux/rbtree.h>
33
34 #include <cluster/masklog.h>
35
36 #include "ocfs2.h"
37
38 #include "aops.h"
39 #include "dlmglue.h"
40 #include "file.h"
41 #include "inode.h"
42 #include "mmap.h"
43 #include "super.h"
44 #include "ocfs2_trace.h"
45
46
ocfs2_fault(struct vm_area_struct * area,struct vm_fault * vmf)47 static int ocfs2_fault(struct vm_area_struct *area, struct vm_fault *vmf)
48 {
49 sigset_t oldset;
50 int ret;
51
52 ocfs2_block_signals(&oldset);
53 ret = filemap_fault(area, vmf);
54 ocfs2_unblock_signals(&oldset);
55
56 trace_ocfs2_fault(OCFS2_I(area->vm_file->f_mapping->host)->ip_blkno,
57 area, vmf->page, vmf->pgoff);
58 return ret;
59 }
60
__ocfs2_page_mkwrite(struct file * file,struct buffer_head * di_bh,struct page * page)61 static int __ocfs2_page_mkwrite(struct file *file, struct buffer_head *di_bh,
62 struct page *page)
63 {
64 int ret;
65 struct inode *inode = file->f_path.dentry->d_inode;
66 struct address_space *mapping = inode->i_mapping;
67 loff_t pos = page_offset(page);
68 unsigned int len = PAGE_CACHE_SIZE;
69 pgoff_t last_index;
70 struct page *locked_page = NULL;
71 void *fsdata;
72 loff_t size = i_size_read(inode);
73
74 /*
75 * Another node might have truncated while we were waiting on
76 * cluster locks.
77 * We don't check size == 0 before the shift. This is borrowed
78 * from do_generic_file_read.
79 */
80 last_index = (size - 1) >> PAGE_CACHE_SHIFT;
81 if (unlikely(!size || page->index > last_index)) {
82 ret = -EINVAL;
83 goto out;
84 }
85
86 /*
87 * The i_size check above doesn't catch the case where nodes
88 * truncated and then re-extended the file. We'll re-check the
89 * page mapping after taking the page lock inside of
90 * ocfs2_write_begin_nolock().
91 */
92 if (!PageUptodate(page) || page->mapping != inode->i_mapping) {
93 /*
94 * the page has been umapped in ocfs2_data_downconvert_worker.
95 * So return 0 here and let VFS retry.
96 */
97 ret = 0;
98 goto out;
99 }
100
101 /*
102 * Call ocfs2_write_begin() and ocfs2_write_end() to take
103 * advantage of the allocation code there. We pass a write
104 * length of the whole page (chopped to i_size) to make sure
105 * the whole thing is allocated.
106 *
107 * Since we know the page is up to date, we don't have to
108 * worry about ocfs2_write_begin() skipping some buffer reads
109 * because the "write" would invalidate their data.
110 */
111 if (page->index == last_index)
112 len = ((size - 1) & ~PAGE_CACHE_MASK) + 1;
113
114 ret = ocfs2_write_begin_nolock(file, mapping, pos, len, 0, &locked_page,
115 &fsdata, di_bh, page);
116 if (ret) {
117 if (ret != -ENOSPC)
118 mlog_errno(ret);
119 goto out;
120 }
121
122 ret = ocfs2_write_end_nolock(mapping, pos, len, len, locked_page,
123 fsdata);
124 if (ret < 0) {
125 mlog_errno(ret);
126 goto out;
127 }
128 BUG_ON(ret != len);
129 ret = 0;
130 out:
131 return ret;
132 }
133
ocfs2_page_mkwrite(struct vm_area_struct * vma,struct vm_fault * vmf)134 static int ocfs2_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
135 {
136 struct page *page = vmf->page;
137 struct inode *inode = vma->vm_file->f_path.dentry->d_inode;
138 struct buffer_head *di_bh = NULL;
139 sigset_t oldset;
140 int ret;
141
142 ocfs2_block_signals(&oldset);
143
144 /*
145 * The cluster locks taken will block a truncate from another
146 * node. Taking the data lock will also ensure that we don't
147 * attempt page truncation as part of a downconvert.
148 */
149 ret = ocfs2_inode_lock(inode, &di_bh, 1);
150 if (ret < 0) {
151 mlog_errno(ret);
152 goto out;
153 }
154
155 /*
156 * The alloc sem should be enough to serialize with
157 * ocfs2_truncate_file() changing i_size as well as any thread
158 * modifying the inode btree.
159 */
160 down_write(&OCFS2_I(inode)->ip_alloc_sem);
161
162 ret = __ocfs2_page_mkwrite(vma->vm_file, di_bh, page);
163
164 up_write(&OCFS2_I(inode)->ip_alloc_sem);
165
166 brelse(di_bh);
167 ocfs2_inode_unlock(inode, 1);
168
169 out:
170 ocfs2_unblock_signals(&oldset);
171 if (ret)
172 ret = VM_FAULT_SIGBUS;
173 return ret;
174 }
175
176 static const struct vm_operations_struct ocfs2_file_vm_ops = {
177 .fault = ocfs2_fault,
178 .page_mkwrite = ocfs2_page_mkwrite,
179 };
180
ocfs2_mmap(struct file * file,struct vm_area_struct * vma)181 int ocfs2_mmap(struct file *file, struct vm_area_struct *vma)
182 {
183 int ret = 0, lock_level = 0;
184
185 ret = ocfs2_inode_lock_atime(file->f_dentry->d_inode,
186 file->f_vfsmnt, &lock_level);
187 if (ret < 0) {
188 mlog_errno(ret);
189 goto out;
190 }
191 ocfs2_inode_unlock(file->f_dentry->d_inode, lock_level);
192 out:
193 vma->vm_ops = &ocfs2_file_vm_ops;
194 vma->vm_flags |= VM_CAN_NONLINEAR;
195 return 0;
196 }
197
198