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>
26 #include <linux/namei.h>
28 /* Symlink caching in the page cache is even more simplistic
29 * and straight-forward than readdir caching.
31 static int nfs_symlink_filler(struct inode *inode, struct page *page)
35 /* We place the length at the beginning of the page,
36 * in host byte order, followed by the string. The
37 * XDR response verification will NULL terminate it.
40 error = NFS_PROTO(inode)->readlink(inode, page);
44 SetPageUptodate(page);
55 Page_Offset = (PAGE_SIZE - sizeof(void *)) / 4
58 static int nfs_follow_link(struct dentry *dentry, struct nameidata *nd)
60 struct inode *inode = dentry->d_inode;
64 page = ERR_PTR(nfs_revalidate_inode(NFS_SERVER(inode), inode));
67 page = read_cache_page(&inode->i_data, 0,
68 (filler_t *)nfs_symlink_filler, inode);
71 if (!PageUptodate(page))
72 goto getlink_read_error;
74 if (*p > Page_Offset * 4 - 1 - 4)
76 *(struct page **)(p + Page_Offset) = page;
78 nd_set_link(nd, (char *)(p+1));
83 page_cache_release(page);
84 page = ERR_PTR(-ENAMETOOLONG);
87 page_cache_release(page);
90 nd_set_link(nd, (char*)page);
94 static void nfs_put_link(struct dentry *dentry, struct nameidata *nd)
96 u32 *s = (u32 *)nd_get_link(nd);
98 struct page *page = *(struct page **)(s + Page_Offset - 1);
100 page_cache_release(page);
105 * symlinks can't do much...
107 struct inode_operations nfs_symlink_inode_operations = {
108 .readlink = generic_readlink,
109 .follow_link = nfs_follow_link,
110 .put_link = nfs_put_link,
111 .getattr = nfs_getattr,
112 .setattr = nfs_setattr,