fs/9p/vfs_addr.c

   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 version 2
  11  *  as published by the Free Software Foundation.
  12  *
  13  *  This program is distributed in the hope that it will be useful,
  14  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  *  GNU General Public License for more details.
  17  *
  18  *  You should have received a copy of the GNU General Public License
  19  *  along with this program; if not, write to:
  20  *  Free Software Foundation
  21  *  51 Franklin Street, Fifth Floor
  22  *  Boston, MA  02111-1301  USA
  23  *
  24  */
  25
  26 #include <linux/module.h>
  27 #include <linux/errno.h>
  28 #include <linux/fs.h>
  29 #include <linux/file.h>
  30 #include <linux/stat.h>
  31 #include <linux/string.h>
  32 #include <linux/inet.h>
  33 #include <linux/pagemap.h>
  34 #include <linux/idr.h>
  35 #include <linux/sched.h>
  36
  37 #include "debug.h"
  38 #include "v9fs.h"
  39 #include "9p.h"
  40 #include "v9fs_vfs.h"
  41 #include "fid.h"
  42
  43 /**
  44  * v9fs_vfs_readpage - read an entire page in from 9P
  45  *
  46  * @file: file being read
  47  * @page: structure to page
  48  *
  49  */
  50
  51 static int v9fs_vfs_readpage(struct file *filp, struct page *page)
  52 {
  53         char *buffer = NULL;
  54         int retval = -EIO;
  55         loff_t offset = page_offset(page);
  56         int count = PAGE_CACHE_SIZE;
  57         struct inode *inode = filp->f_path.dentry->d_inode;
  58         struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
  59         int rsize = v9ses->maxdata - V9FS_IOHDRSZ;
  60         struct v9fs_fid *v9f = filp->private_data;
  61         struct v9fs_fcall *fcall = NULL;
  62         int fid = v9f->fid;
  63         int total = 0;
  64         int result = 0;
  65
  66         dprintk(DEBUG_VFS, "\n");
  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
 101 UnmapAndUnlock:
 102         kunmap(page);
 103         unlock_page(page);
 104         return retval;
 105 }
 106
 107 const struct address_space_operations v9fs_addr_operations = {
 108       .readpage = v9fs_vfs_readpage,
 109 };