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[PATCH] v9fs: add readpage support
[people/ms/linux.git] / fs / 9p / vfs_addr.c
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EVH
1/*
2 * linux/fs/9p/vfs_addr.c
3 *
4 * This file contians vfs address (mmap) ops for 9P2000.
5 *
6 * Copyright (C) 2005 by Eric Van Hensbergen <ericvh@gmail.com>
7 * Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
8 *
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License as published by
11 * the Free Software Foundation; either version 2 of the License, or
12 * (at your option) any later version.
13 *
14 * This program is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 * GNU General Public License for more details.
18 *
19 * You should have received a copy of the GNU General Public License
20 * along with this program; if not, write to:
21 * Free Software Foundation
22 * 51 Franklin Street, Fifth Floor
23 * Boston, MA 02111-1301 USA
24 *
25 */
26
27#include <linux/module.h>
28#include <linux/errno.h>
29#include <linux/fs.h>
30#include <linux/file.h>
31#include <linux/stat.h>
32#include <linux/string.h>
33#include <linux/smp_lock.h>
34#include <linux/inet.h>
35#include <linux/version.h>
36#include <linux/pagemap.h>
37#include <linux/idr.h>
38
39#include "debug.h"
40#include "v9fs.h"
41#include "9p.h"
42#include "v9fs_vfs.h"
43#include "fid.h"
44
45/**
46 * v9fs_vfs_readpage - read an entire page in from 9P
47 *
48 * @file: file being read
49 * @page: structure to page
50 *
51 */
52
53static int v9fs_vfs_readpage(struct file *filp, struct page *page)
54{
55 char *buffer = NULL;
56 int retval = -EIO;
57 loff_t offset = page_offset(page);
58 int count = PAGE_CACHE_SIZE;
59 struct inode *inode = filp->f_dentry->d_inode;
60 struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
61 int rsize = v9ses->maxdata - V9FS_IOHDRSZ;
62 struct v9fs_fid *v9f = filp->private_data;
63 struct v9fs_fcall *fcall = NULL;
64 int fid = v9f->fid;
65 int total = 0;
66 int result = 0;
67
68 buffer = kmap(page);
69 do {
70 if (count < rsize)
71 rsize = count;
72
73 result = v9fs_t_read(v9ses, fid, offset, rsize, &fcall);
74
75 if (result < 0) {
76 printk(KERN_ERR "v9fs_t_read returned %d\n",
77 result);
78
79 kfree(fcall);
80 goto UnmapAndUnlock;
81 } else
82 offset += result;
83
84 memcpy(buffer, fcall->params.rread.data, result);
85
86 count -= result;
87 buffer += result;
88 total += result;
89
90 kfree(fcall);
91
92 if (result < rsize)
93 break;
94 } while (count);
95
96 memset(buffer, 0, count);
97 flush_dcache_page(page);
98 SetPageUptodate(page);
99 retval = 0;
100
101UnmapAndUnlock:
102 kunmap(page);
103 unlock_page(page);
104 return retval;
105}
106
107struct address_space_operations v9fs_addr_operations = {
108 .readpage = v9fs_vfs_readpage,
109};