1/*
2 *  linux/fs/nfs/symlink.c
3 *
4 *  Copyright (C) 1992  Rick Sladkey
5 *
6 *  Optimization changes Copyright (C) 1994 Florian La Roche
7 *
8 *  Jun 7 1999, cache symlink lookups in the page cache.  -DaveM
9 *
10 *  nfs symlink handling code
11 */
12
13#include <linux/time.h>
14#include <linux/errno.h>
15#include <linux/sunrpc/clnt.h>
16#include <linux/nfs.h>
17#include <linux/nfs2.h>
18#include <linux/nfs_fs.h>
19#include <linux/pagemap.h>
20#include <linux/stat.h>
21#include <linux/mm.h>
22#include <linux/string.h>
23
24/* Symlink caching in the page cache is even more simplistic
25 * and straight-forward than readdir caching.
26 */
27
28static int nfs_symlink_filler(struct inode *inode, struct page *page)
29{
30	int error;
31
32	error = NFS_PROTO(inode)->readlink(inode, page, 0, PAGE_SIZE);
33	if (error < 0)
34		goto error;
35	SetPageUptodate(page);
36	unlock_page(page);
37	return 0;
38
39error:
40	SetPageError(page);
41	unlock_page(page);
42	return -EIO;
43}
44
45static const char *nfs_follow_link(struct dentry *dentry, void **cookie)
46{
47	struct inode *inode = d_inode(dentry);
48	struct page *page;
49	void *err;
50
51	err = ERR_PTR(nfs_revalidate_mapping(inode, inode->i_mapping));
52	if (err)
53		return err;
54	page = read_cache_page(&inode->i_data, 0,
55				(filler_t *)nfs_symlink_filler, inode);
56	if (IS_ERR(page))
57		return ERR_CAST(page);
58	*cookie = page;
59	return kmap(page);
60}
61
62/*
63 * symlinks can't do much...
64 */
65const struct inode_operations nfs_symlink_inode_operations = {
66	.readlink	= generic_readlink,
67	.follow_link	= nfs_follow_link,
68	.put_link	= page_put_link,
69	.getattr	= nfs_getattr,
70	.setattr	= nfs_setattr,
71};
72