xref: /openbmc/linux/fs/efs/symlink.c (revision f3539c12)
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 = page_address(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 	unlock_page(page);
43 	return 0;
44 fail:
45 	SetPageError(page);
46 	unlock_page(page);
47 	return err;
48 }
49 
50 const struct address_space_operations efs_symlink_aops = {
51 	.readpage	= efs_symlink_readpage
52 };
53