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
  14 static 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;
  45 fail:
  46         SetPageError(page);
  47         kunmap(page);
  48         unlock_page(page);
  49         return err;
  50 }
  51
  52 const struct address_space_operations efs_symlink_aops = {
  53         .readpage       = efs_symlink_readpage
  54 };