xref: /linux/fs/ocfs2/mmap.c (revision f3d9478b2ce468c3115b02ecae7e975990697f15)
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/slab.h>
29 #include <linux/highmem.h>
30 #include <linux/pagemap.h>
31 #include <linux/uio.h>
32 #include <linux/signal.h>
33 #include <linux/rbtree.h>
34 
35 #define MLOG_MASK_PREFIX ML_FILE_IO
36 #include <cluster/masklog.h>
37 
38 #include "ocfs2.h"
39 
40 #include "dlmglue.h"
41 #include "file.h"
42 #include "inode.h"
43 #include "mmap.h"
44 
45 static struct page *ocfs2_nopage(struct vm_area_struct * area,
46 				 unsigned long address,
47 				 int *type)
48 {
49 	struct inode *inode = area->vm_file->f_dentry->d_inode;
50 	struct page *page = NOPAGE_SIGBUS;
51 	sigset_t blocked, oldset;
52 	int ret;
53 
54 	mlog_entry("(inode %lu, address %lu)\n", inode->i_ino, address);
55 
56 	/* The best way to deal with signals in this path is
57 	 * to block them upfront, rather than allowing the
58 	 * locking paths to return -ERESTARTSYS. */
59 	sigfillset(&blocked);
60 
61 	/* We should technically never get a bad ret return
62 	 * from sigprocmask */
63 	ret = sigprocmask(SIG_BLOCK, &blocked, &oldset);
64 	if (ret < 0) {
65 		mlog_errno(ret);
66 		goto out;
67 	}
68 
69 	page = filemap_nopage(area, address, type);
70 
71 	ret = sigprocmask(SIG_SETMASK, &oldset, NULL);
72 	if (ret < 0)
73 		mlog_errno(ret);
74 out:
75 	mlog_exit_ptr(page);
76 	return page;
77 }
78 
79 static struct vm_operations_struct ocfs2_file_vm_ops = {
80 	.nopage = ocfs2_nopage,
81 };
82 
83 int ocfs2_mmap(struct file *file, struct vm_area_struct *vma)
84 {
85 	/* We don't want to support shared writable mappings yet. */
86 	if (((vma->vm_flags & VM_SHARED) || (vma->vm_flags & VM_MAYSHARE))
87 	    && ((vma->vm_flags & VM_WRITE) || (vma->vm_flags & VM_MAYWRITE))) {
88 		mlog(0, "disallow shared writable mmaps %lx\n", vma->vm_flags);
89 		/* This is -EINVAL because generic_file_readonly_mmap
90 		 * returns it in a similar situation. */
91 		return -EINVAL;
92 	}
93 
94 	file_accessed(file);
95 	vma->vm_ops = &ocfs2_file_vm_ops;
96 	return 0;
97 }
98 
99