LXR linux/fs/efs/symlink.c

   1/*
   2 * symlink.c
   3 *
   4 * Copyright (c) 1999 Al Smith
   5 *
   6 * Portions derived from work (c) 1995,1996 Christian Vogelgsang.
   7 */
   8
   9#include <linux/string.h>
  10#include <linux/pagemap.h>
  11#include <linux/buffer_head.h>
  12#include "efs.h"
  13
  14static int efs_symlink_readpage(struct file *file, struct page *page)
  15{
  16        char *link = kmap(page);
  17        struct buffer_head * bh;
  18        struct inode * inode = page->mapping->host;
  19        efs_block_t size = inode->i_size;
  20        int err;
  21  
  22        err = -ENAMETOOLONG;
  23        if (size > 2 * EFS_BLOCKSIZE)
  24                goto fail;
  25  
  26        /* read first 512 bytes of link target */
  27        err = -EIO;
  28        bh = sb_bread(inode->i_sb, efs_bmap(inode, 0));
  29        if (!bh)
  30                goto fail;
  31        memcpy(link, bh->b_data, (size > EFS_BLOCKSIZE) ? EFS_BLOCKSIZE : size);
  32        brelse(bh);
  33        if (size > EFS_BLOCKSIZE) {
  34                bh = sb_bread(inode->i_sb, efs_bmap(inode, 1));
  35                if (!bh)
  36                        goto fail;
  37                memcpy(link + EFS_BLOCKSIZE, bh->b_data, size - EFS_BLOCKSIZE);
  38                brelse(bh);
  39        }
  40        link[size] = '\0';
  41        SetPageUptodate(page);
  42        kunmap(page);
  43        unlock_page(page);
  44        return 0;
  45fail:
  46        SetPageError(page);
  47        kunmap(page);
  48        unlock_page(page);
  49        return err;
  50}
  51
  52const struct address_space_operations efs_symlink_aops = {
  53        .readpage       = efs_symlink_readpage
  54};
  55