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 | struct page *page = &folio->page; |
18 | char *link = page_address(page); |
19 | struct buffer_head * bh; |
20 | struct inode * inode = page->mapping->host; |
21 | efs_block_t size = inode->i_size; |
22 | int err; |
23 | |
24 | err = -ENAMETOOLONG; |
25 | if (size > 2 * EFS_BLOCKSIZE) |
26 | goto fail; |
27 | |
28 | /* read first 512 bytes of link target */ |
29 | err = -EIO; |
30 | bh = sb_bread(sb: inode->i_sb, block: efs_bmap(inode, 0)); |
31 | if (!bh) |
32 | goto fail; |
33 | memcpy(link, bh->b_data, (size > EFS_BLOCKSIZE) ? EFS_BLOCKSIZE : size); |
34 | brelse(bh); |
35 | if (size > EFS_BLOCKSIZE) { |
36 | bh = sb_bread(sb: inode->i_sb, block: efs_bmap(inode, 1)); |
37 | if (!bh) |
38 | goto fail; |
39 | memcpy(link + EFS_BLOCKSIZE, bh->b_data, size - EFS_BLOCKSIZE); |
40 | brelse(bh); |
41 | } |
42 | link[size] = '\0'; |
43 | SetPageUptodate(page); |
44 | unlock_page(page); |
45 | return 0; |
46 | fail: |
47 | SetPageError(page); |
48 | unlock_page(page); |
49 | return err; |
50 | } |
51 | |
52 | const struct address_space_operations efs_symlink_aops = { |
53 | .read_folio = efs_symlink_read_folio |
54 | }; |
55 | |