1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
|
// SPDX-License-Identifier: GPL-2.0-or-later
/* -*- mode: c; c-basic-offset: 8; -*-
* vim: noexpandtab sw=8 ts=8 sts=0:
*
* mmap.c
*
* Code to deal with the mess that is clustered mmap.
*
* Copyright (C) 2002, 2004 Oracle. All rights reserved.
*/
#include <linux/fs.h>
#include <linux/types.h>
#include <linux/highmem.h>
#include <linux/pagemap.h>
#include <linux/uio.h>
#include <linux/signal.h>
#include <linux/rbtree.h>
#include <cluster/masklog.h>
#include "ocfs2.h"
#include "aops.h"
#include "dlmglue.h"
#include "file.h"
#include "inode.h"
#include "mmap.h"
#include "super.h"
#include "ocfs2_trace.h"
static vm_fault_t ocfs2_fault(struct vm_fault *vmf)
{
struct vm_area_struct *vma = vmf->vma;
sigset_t oldset;
vm_fault_t ret;
ocfs2_block_signals(&oldset);
ret = filemap_fault(vmf);
ocfs2_unblock_signals(&oldset);
trace_ocfs2_fault(OCFS2_I(vma->vm_file->f_mapping->host)->ip_blkno,
vma, vmf->page, vmf->pgoff);
return ret;
}
static vm_fault_t __ocfs2_page_mkwrite(struct file *file,
struct buffer_head *di_bh, struct page *page)
{
int err;
vm_fault_t ret = VM_FAULT_NOPAGE;
struct inode *inode = file_inode(file);
struct address_space *mapping = inode->i_mapping;
loff_t pos = page_offset(page);
unsigned int len = PAGE_SIZE;
pgoff_t last_index;
struct page *locked_page = NULL;
void *fsdata;
loff_t size = i_size_read(inode);
last_index = (size - 1) >> PAGE_SHIFT;
/*
* There are cases that lead to the page no longer belonging to the
* mapping.
* 1) pagecache truncates locally due to memory pressure.
* 2) pagecache truncates when another is taking EX lock against
* inode lock. see ocfs2_data_convert_worker.
*
* The i_size check doesn't catch the case where nodes truncated and
* then re-extended the file. We'll re-check the page mapping after
* taking the page lock inside of ocfs2_write_begin_nolock().
*
* Let VM retry with these cases.
*/
if ((page->mapping != inode->i_mapping) ||
(!PageUptodate(page)) ||
(page_offset(page) >= size))
goto out;
/*
* Call ocfs2_write_begin() and ocfs2_write_end() to take
* advantage of the allocation code there. We pass a write
* length of the whole page (chopped to i_size) to make sure
* the whole thing is allocated.
*
* Since we know the page is up to date, we don't have to
* worry about ocfs2_write_begin() skipping some buffer reads
* because the "write" would invalidate their data.
*/
if (page->index == last_index)
len = ((size - 1) & ~PAGE_MASK) + 1;
err = ocfs2_write_begin_nolock(mapping, pos, len, OCFS2_WRITE_MMAP,
&locked_page, &fsdata, di_bh, page);
if (err) {
if (err != -ENOSPC)
mlog_errno(err);
ret = vmf_error(err);
goto out;
}
if (!locked_page) {
ret = VM_FAULT_NOPAGE;
goto out;
}
err = ocfs2_write_end_nolock(mapping, pos, len, len, fsdata);
BUG_ON(err != len);
ret = VM_FAULT_LOCKED;
out:
return ret;
}
static vm_fault_t ocfs2_page_mkwrite(struct vm_fault *vmf)
{
struct page *page = vmf->page;
struct inode *inode = file_inode(vmf->vma->vm_file);
struct buffer_head *di_bh = NULL;
sigset_t oldset;
int err;
vm_fault_t ret;
sb_start_pagefault(inode->i_sb);
ocfs2_block_signals(&oldset);
/*
* The cluster locks taken will block a truncate from another
* node. Taking the data lock will also ensure that we don't
* attempt page truncation as part of a downconvert.
*/
err = ocfs2_inode_lock(inode, &di_bh, 1);
if (err < 0) {
mlog_errno(err);
ret = vmf_error(err);
goto out;
}
/*
* The alloc sem should be enough to serialize with
* ocfs2_truncate_file() changing i_size as well as any thread
* modifying the inode btree.
*/
down_write(&OCFS2_I(inode)->ip_alloc_sem);
ret = __ocfs2_page_mkwrite(vmf->vma->vm_file, di_bh, page);
up_write(&OCFS2_I(inode)->ip_alloc_sem);
brelse(di_bh);
ocfs2_inode_unlock(inode, 1);
out:
ocfs2_unblock_signals(&oldset);
sb_end_pagefault(inode->i_sb);
return ret;
}
static const struct vm_operations_struct ocfs2_file_vm_ops = {
.fault = ocfs2_fault,
.page_mkwrite = ocfs2_page_mkwrite,
};
int ocfs2_mmap(struct file *file, struct vm_area_struct *vma)
{
int ret = 0, lock_level = 0;
ret = ocfs2_inode_lock_atime(file_inode(file),
file->f_path.mnt, &lock_level, 1);
if (ret < 0) {
mlog_errno(ret);
goto out;
}
ocfs2_inode_unlock(file_inode(file), lock_level);
out:
vma->vm_ops = &ocfs2_file_vm_ops;
return 0;
}
|
