2 * linux/fs/nfs/symlink.c
4 * Copyright (C) 1992 Rick Sladkey
6 * Optimization changes Copyright (C) 1994 Florian La Roche
8 * Jun 7 1999, cache symlink lookups in the page cache. -DaveM
10 * nfs symlink handling code
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>
23 #include <linux/slab.h>
24 #include <linux/string.h>
25 #include <linux/smp_lock.h>
27 /* Symlink caching in the page cache is even more simplistic
28 * and straight-forward than readdir caching.
30 static int nfs_symlink_filler(struct inode *inode, struct page *page)
34 /* We place the length at the beginning of the page,
35 * in host byte order, followed by the string. The
36 * XDR response verification will NULL terminate it.
39 error = NFS_PROTO(inode)->readlink(inode, page);
43 SetPageUptodate(page);
53 static char *nfs_getlink(struct inode *inode, struct page **ppage)
58 page = ERR_PTR(nfs_revalidate_inode(NFS_SERVER(inode), inode));
61 page = read_cache_page(&inode->i_data, 0,
62 (filler_t *)nfs_symlink_filler, inode);
65 if (!PageUptodate(page))
66 goto getlink_read_error;
72 page_cache_release(page);
78 static int nfs_readlink(struct dentry *dentry, char __user *buffer, int buflen)
80 struct inode *inode = dentry->d_inode;
81 struct page *page = NULL;
82 int res = vfs_readlink(dentry,buffer,buflen,nfs_getlink(inode,&page));
85 page_cache_release(page);
90 static int nfs_follow_link(struct dentry *dentry, struct nameidata *nd)
92 struct inode *inode = dentry->d_inode;
93 struct page *page = NULL;
94 int res = vfs_follow_link(nd, nfs_getlink(inode,&page));
97 page_cache_release(page);
103 * symlinks can't do much...
105 struct inode_operations nfs_symlink_inode_operations = {
106 .readlink = nfs_readlink,
107 .follow_link = nfs_follow_link,
108 .getattr = nfs_getattr,
109 .setattr = nfs_setattr,