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 #include <linux/namei.h>
24
25 /* Symlink caching in the page cache is even more simplistic
26 * and straight-forward than readdir caching.
27 */
28
nfs_symlink_filler(struct inode * inode,struct page * page)29 static int nfs_symlink_filler(struct inode *inode, struct page *page)
30 {
31 int error;
32
33 error = NFS_PROTO(inode)->readlink(inode, page, 0, PAGE_SIZE);
34 if (error < 0)
35 goto error;
36 SetPageUptodate(page);
37 unlock_page(page);
38 return 0;
39
40 error:
41 SetPageError(page);
42 unlock_page(page);
43 return -EIO;
44 }
45
nfs_follow_link(struct dentry * dentry,struct nameidata * nd)46 static void *nfs_follow_link(struct dentry *dentry, struct nameidata *nd)
47 {
48 struct inode *inode = dentry->d_inode;
49 struct page *page;
50 void *err;
51
52 err = ERR_PTR(nfs_revalidate_mapping(inode, inode->i_mapping));
53 if (err)
54 goto read_failed;
55 page = read_cache_page(&inode->i_data, 0,
56 (filler_t *)nfs_symlink_filler, inode);
57 if (IS_ERR(page)) {
58 err = page;
59 goto read_failed;
60 }
61 nd_set_link(nd, kmap(page));
62 return page;
63
64 read_failed:
65 nd_set_link(nd, err);
66 return NULL;
67 }
68
69 /*
70 * symlinks can't do much...
71 */
72 const struct inode_operations nfs_symlink_inode_operations = {
73 .readlink = generic_readlink,
74 .follow_link = nfs_follow_link,
75 .put_link = page_put_link,
76 .getattr = nfs_getattr,
77 .setattr = nfs_setattr,
78 };
79