summaryrefslogtreecommitdiff
path: root/fs/9p/vfs_addr.c
blob: 90e38449f4b3a7dd0ab5c642e63bc504eb5adaef (plain)
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
/*
 *  linux/fs/9p/vfs_addr.c
 *
 * This file contians vfs address (mmap) ops for 9P2000.
 *
 *  Copyright (C) 2005 by Eric Van Hensbergen <ericvh@gmail.com>
 *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License version 2
 *  as published by the Free Software Foundation.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to:
 *  Free Software Foundation
 *  51 Franklin Street, Fifth Floor
 *  Boston, MA  02111-1301  USA
 *
 */

#include <linux/module.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/stat.h>
#include <linux/string.h>
#include <linux/inet.h>
#include <linux/pagemap.h>
#include <linux/idr.h>
#include <linux/sched.h>
#include <net/9p/9p.h>
#include <net/9p/client.h>

#include "v9fs.h"
#include "v9fs_vfs.h"
#include "cache.h"

/**
 * v9fs_vfs_readpage - read an entire page in from 9P
 *
 * @filp: file being read
 * @page: structure to page
 *
 */

static int v9fs_vfs_readpage(struct file *filp, struct page *page)
{
	int retval;
	loff_t offset;
	char *buffer;
	struct inode *inode;

	inode = page->mapping->host;
	P9_DPRINTK(P9_DEBUG_VFS, "\n");

	BUG_ON(!PageLocked(page));

	retval = v9fs_readpage_from_fscache(inode, page);
	if (retval == 0)
		return retval;

	buffer = kmap(page);
	offset = page_offset(page);

	retval = v9fs_file_readn(filp, buffer, NULL, PAGE_CACHE_SIZE, offset);
	if (retval < 0) {
		v9fs_uncache_page(inode, page);
		goto done;
	}

	memset(buffer + retval, 0, PAGE_CACHE_SIZE - retval);
	flush_dcache_page(page);
	SetPageUptodate(page);

	v9fs_readpage_to_fscache(inode, page);
	retval = 0;

done:
	kunmap(page);
	unlock_page(page);
	return retval;
}

/**
 * v9fs_vfs_readpages - read a set of pages from 9P
 *
 * @filp: file being read
 * @mapping: the address space
 * @pages: list of pages to read
 * @nr_pages: count of pages to read
 *
 */

static int v9fs_vfs_readpages(struct file *filp, struct address_space *mapping,
			     struct list_head *pages, unsigned nr_pages)
{
	int ret = 0;
	struct inode *inode;

	inode = mapping->host;
	P9_DPRINTK(P9_DEBUG_VFS, "inode: %p file: %p\n", inode, filp);

	ret = v9fs_readpages_from_fscache(inode, mapping, pages, &nr_pages);
	if (ret == 0)
		return ret;

	ret = read_cache_pages(mapping, pages, (void *)v9fs_vfs_readpage, filp);
	P9_DPRINTK(P9_DEBUG_VFS, "  = %d\n", ret);
	return ret;
}

/**
 * v9fs_release_page - release the private state associated with a page
 *
 * Returns 1 if the page can be released, false otherwise.
 */

static int v9fs_release_page(struct page *page, gfp_t gfp)
{
	if (PagePrivate(page))
		return 0;

	return v9fs_fscache_release_page(page, gfp);
}

/**
 * v9fs_invalidate_page - Invalidate a page completely or partially
 *
 * @page: structure to page
 * @offset: offset in the page
 */

static void v9fs_invalidate_page(struct page *page, unsigned long offset)
{
	if (offset == 0)
		v9fs_fscache_invalidate_page(page);
}

/**
 * v9fs_launder_page - Writeback a dirty page
 * Since the writes go directly to the server, we simply return a 0
 * here to indicate success.
 *
 * Returns 0 on success.
 */

static int v9fs_launder_page(struct page *page)
{
	return 0;
}

const struct address_space_operations v9fs_addr_operations = {
      .readpage = v9fs_vfs_readpage,
      .readpages = v9fs_vfs_readpages,
      .releasepage = v9fs_release_page,
      .invalidatepage = v9fs_invalidate_page,
      .launder_page = v9fs_launder_page,
};