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
  15 static int efs_symlink_read_folio(struct file *file, struct folio *folio)
  16 {
  17         char *link = folio_address(folio);
  18         struct buffer_head *bh;
  19         struct inode *inode = folio->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         err = 0;
  43 fail:
  44         folio_end_read(folio, err == 0);
  45         return err;
  46 }
  47
  48 const struct address_space_operations efs_symlink_aops = {
  49         .read_folio     = efs_symlink_read_folio
  50 };