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/smp_lock.h>
  33 #include <linux/inet.h>
  34 #include <linux/pagemap.h>
  35 #include <linux/idr.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         buffer = kmap(page);
  67         do {
  68                 if (count < rsize)
  69                         rsize = count;
  70
  71                 result = v9fs_t_read(v9ses, fid, offset, rsize, &fcall);
  72
  73                 if (result < 0) {
  74                         printk(KERN_ERR "v9fs_t_read returned %d\n",
  75                                result);
  76
  77                         kfree(fcall);
  78                         goto UnmapAndUnlock;
  79                 } else
  80                         offset += result;
  81
  82                 memcpy(buffer, fcall->params.rread.data, result);
  83
  84                 count -= result;
  85                 buffer += result;
  86                 total += result;
  87
  88                 kfree(fcall);
  89
  90                 if (result < rsize)
  91                         break;
  92         } while (count);
  93
  94         memset(buffer, 0, count);
  95         flush_dcache_page(page);
  96         SetPageUptodate(page);
  97         retval = 0;
  98
  99 UnmapAndUnlock:
 100         kunmap(page);
 101         unlock_page(page);
 102         return retval;
 103 }
 104
 105 const struct address_space_operations v9fs_addr_operations = {
 106       .readpage = v9fs_vfs_readpage,
 107 };