tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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#define NFS_NEED_XDR_TYPES
14#include <linux/time.h>
15#include <linux/errno.h>
16#include <linux/sunrpc/clnt.h>
17#include <linux/nfs.h>
18#include <linux/nfs2.h>
19#include <linux/nfs_fs.h>
20#include <linux/pagemap.h>
21#include <linux/stat.h>
22#include <linux/mm.h>
23#include <linux/slab.h>
24#include <linux/string.h>
25#include <linux/smp_lock.h>
26#include <linux/namei.h>
27
28/* Symlink caching in the page cache is even more simplistic
29 * and straight-forward than readdir caching.
30 */
31
32static int nfs_symlink_filler(struct inode *inode, struct page *page)
33{
34 int error;
35
36 lock_kernel();
37 error = NFS_PROTO(inode)->readlink(inode, page, 0, PAGE_SIZE);
38 unlock_kernel();
39 if (error < 0)
40 goto error;
41 SetPageUptodate(page);
42 unlock_page(page);
43 return 0;
44
45error:
46 SetPageError(page);
47 unlock_page(page);
48 return -EIO;
49}
50
51static void *nfs_follow_link(struct dentry *dentry, struct nameidata *nd)
52{
53 struct inode *inode = dentry->d_inode;
54 struct page *page;
55 void *err = ERR_PTR(nfs_revalidate_inode(NFS_SERVER(inode), inode));
56 if (err)
57 goto read_failed;
58 page = read_cache_page(&inode->i_data, 0,
59 (filler_t *)nfs_symlink_filler, inode);
60 if (IS_ERR(page)) {
61 err = page;
62 goto read_failed;
63 }
64 if (!PageUptodate(page)) {
65 err = ERR_PTR(-EIO);
66 goto getlink_read_error;
67 }
68 nd_set_link(nd, kmap(page));
69 return page;
70
71getlink_read_error:
72 page_cache_release(page);
73read_failed:
74 nd_set_link(nd, err);
75 return NULL;
76}
77
78static void nfs_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie)
79{
80 if (cookie) {
81 struct page *page = cookie;
82 kunmap(page);
83 page_cache_release(page);
84 }
85}
86
87/*
88 * symlinks can't do much...
89 */
90struct inode_operations nfs_symlink_inode_operations = {
91 .readlink = generic_readlink,
92 .follow_link = nfs_follow_link,
93 .put_link = nfs_put_link,
94 .getattr = nfs_getattr,
95 .setattr = nfs_setattr,
96};