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/efs_fs.h>
  11 #include <linux/pagemap.h>
  12 #include <linux/smp_lock.h>
  13
  14 static int efs_symlink_readpage(struct file *file, struct page *page)
  15 {
  16         char *link = (char*)kmap(page);
  17         struct buffer_head * bh;
  18         struct inode * inode = (struct 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         lock_kernel();
  27         /* read first 512 bytes of link target */
  28         err = -EIO;
  29         bh = bread(inode->i_dev, efs_bmap(inode, 0), EFS_BLOCKSIZE);
  30         if (!bh)
  31                 goto fail;
  32         memcpy(link, bh->b_data, (size > EFS_BLOCKSIZE) ? EFS_BLOCKSIZE : size);
  33         brelse(bh);
  34         if (size > EFS_BLOCKSIZE) {
  35                 bh = bread(inode->i_dev, efs_bmap(inode, 1), EFS_BLOCKSIZE);
  36                 if (!bh)
  37                         goto fail;
  38                 memcpy(link + EFS_BLOCKSIZE, bh->b_data, size - EFS_BLOCKSIZE);
  39                 brelse(bh);
  40         }
  41         link[size] = '\0';
  42         unlock_kernel();
  43         SetPageUptodate(page);
  44         kunmap(page);
  45         UnlockPage(page);
  46         return 0;
  47 fail:
  48         unlock_kernel();
  49         SetPageError(page);
  50         kunmap(page);
  51         UnlockPage(page);
  52         return err;
  53 }
  54
  55 struct address_space_operations efs_symlink_aops = {
  56         readpage:       efs_symlink_readpage
  57 };