LXR linux/fs/efs/symlink.c

   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * symlink.c
   4 *
   5 * Copyright (c) 1999 Al Smith
   6 *
   7 * Portions derived from work (c) 1995,1996 Christian Vogelgsang.
   8 */
   9
  10#include <linux/string.h>
  11#include <linux/pagemap.h>
  12#include <linux/buffer_head.h>
  13#include "efs.h"
  14
  15static int efs_symlink_readpage(struct file *file, struct page *page)
  16{
  17        char *link = page_address(page);
  18        struct buffer_head * bh;
  19        struct inode * inode = page->mapping->host;
  20        efs_block_t size = inode->i_size;
  21        int err;
  22  
  23        err = -ENAMETOOLONG;
  24        if (size > 2 * EFS_BLOCKSIZE)
  25                goto fail;
  26  
  27        /* read first 512 bytes of link target */
  28        err = -EIO;
  29        bh = sb_bread(inode->i_sb, efs_bmap(inode, 0));
  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 = sb_bread(inode->i_sb, efs_bmap(inode, 1));
  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        SetPageUptodate(page);
  43        unlock_page(page);
  44        return 0;
  45fail:
  46        SetPageError(page);
  47        unlock_page(page);
  48        return err;
  49}
  50
  51const struct address_space_operations efs_symlink_aops = {
  52        .readpage       = efs_symlink_readpage
  53};
  54