xref: /openbmc/linux/fs/ocfs2/symlink.c (revision 82ced6fd)
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 #include <linux/namei.h>
43 
44 #define MLOG_MASK_PREFIX ML_NAMEI
45 #include <cluster/masklog.h>
46 
47 #include "ocfs2.h"
48 
49 #include "alloc.h"
50 #include "file.h"
51 #include "inode.h"
52 #include "journal.h"
53 #include "symlink.h"
54 #include "xattr.h"
55 
56 #include "buffer_head_io.h"
57 
58 
59 static char *ocfs2_fast_symlink_getlink(struct inode *inode,
60 					struct buffer_head **bh)
61 {
62 	int status;
63 	char *link = NULL;
64 	struct ocfs2_dinode *fe;
65 
66 	mlog_entry_void();
67 
68 	status = ocfs2_read_inode_block(inode, bh);
69 	if (status < 0) {
70 		mlog_errno(status);
71 		link = ERR_PTR(status);
72 		goto bail;
73 	}
74 
75 	fe = (struct ocfs2_dinode *) (*bh)->b_data;
76 	link = (char *) fe->id2.i_symlink;
77 bail:
78 	mlog_exit(status);
79 
80 	return link;
81 }
82 
83 static int ocfs2_readlink(struct dentry *dentry,
84 			  char __user *buffer,
85 			  int buflen)
86 {
87 	int ret;
88 	char *link;
89 	struct buffer_head *bh = NULL;
90 	struct inode *inode = dentry->d_inode;
91 
92 	mlog_entry_void();
93 
94 	link = ocfs2_fast_symlink_getlink(inode, &bh);
95 	if (IS_ERR(link)) {
96 		ret = PTR_ERR(link);
97 		goto out;
98 	}
99 
100 	/*
101 	 * Without vfsmount we can't update atime now,
102 	 * but we will update atime here ultimately.
103 	 */
104 	ret = vfs_readlink(dentry, buffer, buflen, link);
105 
106 	brelse(bh);
107 out:
108 	mlog_exit(ret);
109 	return ret;
110 }
111 
112 static void *ocfs2_fast_follow_link(struct dentry *dentry,
113 				    struct nameidata *nd)
114 {
115 	int status = 0;
116 	int len;
117 	char *target, *link = ERR_PTR(-ENOMEM);
118 	struct inode *inode = dentry->d_inode;
119 	struct buffer_head *bh = NULL;
120 
121 	mlog_entry_void();
122 
123 	BUG_ON(!ocfs2_inode_is_fast_symlink(inode));
124 	target = ocfs2_fast_symlink_getlink(inode, &bh);
125 	if (IS_ERR(target)) {
126 		status = PTR_ERR(target);
127 		mlog_errno(status);
128 		goto bail;
129 	}
130 
131 	/* Fast symlinks can't be large */
132 	len = strlen(target);
133 	link = kzalloc(len + 1, GFP_NOFS);
134 	if (!link) {
135 		status = -ENOMEM;
136 		mlog_errno(status);
137 		goto bail;
138 	}
139 
140 	memcpy(link, target, len);
141 	nd_set_link(nd, link);
142 
143 bail:
144 	brelse(bh);
145 
146 	mlog_exit(status);
147 	return status ? ERR_PTR(status) : link;
148 }
149 
150 static void ocfs2_fast_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie)
151 {
152 	char *link = cookie;
153 
154 	kfree(link);
155 }
156 
157 const struct inode_operations ocfs2_symlink_inode_operations = {
158 	.readlink	= page_readlink,
159 	.follow_link	= page_follow_link_light,
160 	.put_link	= page_put_link,
161 	.getattr	= ocfs2_getattr,
162 	.setattr	= ocfs2_setattr,
163 	.setxattr	= generic_setxattr,
164 	.getxattr	= generic_getxattr,
165 	.listxattr	= ocfs2_listxattr,
166 	.removexattr	= generic_removexattr,
167 };
168 const struct inode_operations ocfs2_fast_symlink_inode_operations = {
169 	.readlink	= ocfs2_readlink,
170 	.follow_link	= ocfs2_fast_follow_link,
171 	.put_link	= ocfs2_fast_put_link,
172 	.getattr	= ocfs2_getattr,
173 	.setattr	= ocfs2_setattr,
174 	.setxattr	= generic_setxattr,
175 	.getxattr	= generic_getxattr,
176 	.listxattr	= ocfs2_listxattr,
177 	.removexattr	= generic_removexattr,
178 };
179