fs/freevxfs/vxfs_immed.c

   1 /*
   2  * Copyright (c) 2000-2001 Christoph Hellwig.
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions, and the following disclaimer,
  10  *    without modification.
  11  * 2. The name of the author may not be used to endorse or promote products
  12  *    derived from this software without specific prior written permission.
  13  *
  14  * Alternatively, this software may be distributed under the terms of the
  15  * GNU General Public License ("GPL").
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
  21  * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  */
  29
  30 /*
  31  * Veritas filesystem driver - support for 'immed' inodes.
  32  */
  33 #include <linux/fs.h>
  34 #include <linux/pagemap.h>
  35
  36 #include "vxfs.h"
  37 #include "vxfs_extern.h"
  38 #include "vxfs_inode.h"
  39
  40
  41 static int      vxfs_immed_readpage(struct file *, struct page *);
  42
  43 /*
  44  * Address space operations for immed files and directories.
  45  */
  46 const struct address_space_operations vxfs_immed_aops = {
  47         .readpage =             vxfs_immed_readpage,
  48 };
  49
  50 /**
  51  * vxfs_immed_readpage - read part of an immed inode into pagecache
  52  * @file:       file context (unused)
  53  * @page:       page frame to fill in.
  54  *
  55  * Description:
  56  *   vxfs_immed_readpage reads a part of the immed area of the
  57  *   file that hosts @pp into the pagecache.
  58  *
  59  * Returns:
  60  *   Zero on success, else a negative error code.
  61  *
  62  * Locking status:
  63  *   @page is locked and will be unlocked.
  64  */
  65 static int
  66 vxfs_immed_readpage(struct file *fp, struct page *pp)
  67 {
  68         struct vxfs_inode_info  *vip = VXFS_INO(pp->mapping->host);
  69         u_int64_t       offset = (u_int64_t)pp->index << PAGE_CACHE_SHIFT;
  70         caddr_t         kaddr;
  71
  72         kaddr = kmap(pp);
  73         memcpy(kaddr, vip->vii_immed.vi_immed + offset, PAGE_CACHE_SIZE);
  74         kunmap(pp);
  75
  76         flush_dcache_page(pp);
  77         SetPageUptodate(pp);
  78         unlock_page(pp);
  79
  80         return 0;
  81 }