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 #include <net/9p/9p.h>
  37 #include <net/9p/client.h>
  38
  39 #include "v9fs.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         int retval;
  54         loff_t offset;
  55         char *buffer;
  56         struct p9_fid *fid;
  57
  58         P9_DPRINTK(P9_DEBUG_VFS, "\n");
  59         fid = filp->private_data;
  60         buffer = kmap(page);
  61         offset = page_offset(page);
  62
  63         retval = p9_client_readn(fid, buffer, offset, PAGE_CACHE_SIZE);
  64         if (retval < 0)
  65                 goto done;
  66
  67         memset(buffer + retval, 0, PAGE_CACHE_SIZE - retval);
  68         flush_dcache_page(page);
  69         SetPageUptodate(page);
  70         retval = 0;
  71
  72 done:
  73         kunmap(page);
  74         unlock_page(page);
  75         return retval;
  76 }
  77
  78 const struct address_space_operations v9fs_addr_operations = {
  79       .readpage = v9fs_vfs_readpage,
  80 };