1/* -*- mode: c; c-basic-offset: 8; -*-
2 * vim: noexpandtab sw=8 ts=8 sts=0:
3 *
4 *  linux/cluster/ssi/cfs/symlink.c
5 *
6 *	This program is free software; you can redistribute it and/or
7 *	modify it under the terms of the GNU General Public License as
8 *	published by the Free Software Foundation; either version 2 of
9 *	the License, or (at your option) any later version.
10 *
11 *	This program is distributed in the hope that it will be useful,
12 *	but WITHOUT ANY WARRANTY; without even the implied warranty of
13 *	MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE
14 *	or NON INFRINGEMENT.  See the GNU General Public License for more
15 *	details.
16 *
17 * 	You should have received a copy of the GNU General Public License
18 * 	along with this program; if not, write to the Free Software
19 * 	Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
20 *
21 *	Questions/Comments/Bugfixes to ssic-linux-devel@lists.sourceforge.net
22 *
23 *  Copyright (C) 1992  Rick Sladkey
24 *
25 *  Optimization changes Copyright (C) 1994 Florian La Roche
26 *
27 *  Jun 7 1999, cache symlink lookups in the page cache.  -DaveM
28 *
29 *  Portions Copyright (C) 2001 Compaq Computer Corporation
30 *
31 *  ocfs2 symlink handling code.
32 *
33 *  Copyright (C) 2004, 2005 Oracle.
34 *
35 */
36
37#include <linux/fs.h>
38#include <linux/types.h>
39#include <linux/slab.h>
40#include <linux/pagemap.h>
41#include <linux/utsname.h>
42
43#define MLOG_MASK_PREFIX ML_NAMEI
44#include <cluster/masklog.h>
45
46#include "ocfs2.h"
47
48#include "alloc.h"
49#include "file.h"
50#include "inode.h"
51#include "journal.h"
52#include "symlink.h"
53
54#include "buffer_head_io.h"
55
56static char *ocfs2_page_getlink(struct dentry * dentry,
57				struct page **ppage);
58static char *ocfs2_fast_symlink_getlink(struct inode *inode,
59					struct buffer_head **bh);
60
61/* get the link contents into pagecache */
62static char *ocfs2_page_getlink(struct dentry * dentry,
63				struct page **ppage)
64{
65	struct page * page;
66	struct address_space *mapping = dentry->d_inode->i_mapping;
67	page = read_mapping_page(mapping, 0, NULL);
68	if (IS_ERR(page))
69		goto sync_fail;
70	*ppage = page;
71	return kmap(page);
72
73sync_fail:
74	return (char*)page;
75}
76
77static char *ocfs2_fast_symlink_getlink(struct inode *inode,
78					struct buffer_head **bh)
79{
80	int status;
81	char *link = NULL;
82	struct ocfs2_dinode *fe;
83
84	mlog_entry_void();
85
86	status = ocfs2_read_block(OCFS2_SB(inode->i_sb),
87				  OCFS2_I(inode)->ip_blkno,
88				  bh,
89				  OCFS2_BH_CACHED,
90				  inode);
91	if (status < 0) {
92		mlog_errno(status);
93		link = ERR_PTR(status);
94		goto bail;
95	}
96
97	fe = (struct ocfs2_dinode *) (*bh)->b_data;
98	link = (char *) fe->id2.i_symlink;
99bail:
100	mlog_exit(status);
101
102	return link;
103}
104
105static int ocfs2_readlink(struct dentry *dentry,
106			  char __user *buffer,
107			  int buflen)
108{
109	int ret;
110	char *link;
111	struct buffer_head *bh = NULL;
112	struct inode *inode = dentry->d_inode;
113
114	mlog_entry_void();
115
116	link = ocfs2_fast_symlink_getlink(inode, &bh);
117	if (IS_ERR(link)) {
118		ret = PTR_ERR(link);
119		goto out;
120	}
121
122	/*
123	 * Without vfsmount we can't update atime now,
124	 * but we will update atime here ultimately.
125	 */
126	ret = vfs_readlink(dentry, buffer, buflen, link);
127
128	brelse(bh);
129out:
130	mlog_exit(ret);
131	return ret;
132}
133
134static void *ocfs2_follow_link(struct dentry *dentry,
135			       struct nameidata *nd)
136{
137	int status;
138	char *link;
139	struct inode *inode = dentry->d_inode;
140	struct page *page = NULL;
141	struct buffer_head *bh = NULL;
142
143	if (ocfs2_inode_is_fast_symlink(inode))
144		link = ocfs2_fast_symlink_getlink(inode, &bh);
145	else
146		link = ocfs2_page_getlink(dentry, &page);
147	if (IS_ERR(link)) {
148		status = PTR_ERR(link);
149		mlog_errno(status);
150		goto bail;
151	}
152
153	status = vfs_follow_link(nd, link);
154
155bail:
156	if (page) {
157		kunmap(page);
158		page_cache_release(page);
159	}
160	if (bh)
161		brelse(bh);
162
163	return ERR_PTR(status);
164}
165
166const struct inode_operations ocfs2_symlink_inode_operations = {
167	.readlink	= page_readlink,
168	.follow_link	= ocfs2_follow_link,
169	.getattr	= ocfs2_getattr,
170};
171const struct inode_operations ocfs2_fast_symlink_inode_operations = {
172	.readlink	= ocfs2_readlink,
173	.follow_link	= ocfs2_follow_link,
174	.getattr	= ocfs2_getattr,
175};
176