xref: /openbmc/linux/fs/ocfs2/symlink.c (revision 9ac8d3fb)
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 #include "xattr.h"
54 
55 #include "buffer_head_io.h"
56 
57 static char *ocfs2_page_getlink(struct dentry * dentry,
58 				struct page **ppage);
59 static char *ocfs2_fast_symlink_getlink(struct inode *inode,
60 					struct buffer_head **bh);
61 
62 /* get the link contents into pagecache */
63 static char *ocfs2_page_getlink(struct dentry * dentry,
64 				struct page **ppage)
65 {
66 	struct page * page;
67 	struct address_space *mapping = dentry->d_inode->i_mapping;
68 	page = read_mapping_page(mapping, 0, NULL);
69 	if (IS_ERR(page))
70 		goto sync_fail;
71 	*ppage = page;
72 	return kmap(page);
73 
74 sync_fail:
75 	return (char*)page;
76 }
77 
78 static char *ocfs2_fast_symlink_getlink(struct inode *inode,
79 					struct buffer_head **bh)
80 {
81 	int status;
82 	char *link = NULL;
83 	struct ocfs2_dinode *fe;
84 
85 	mlog_entry_void();
86 
87 	status = ocfs2_read_block(inode, OCFS2_I(inode)->ip_blkno, bh);
88 	if (status < 0) {
89 		mlog_errno(status);
90 		link = ERR_PTR(status);
91 		goto bail;
92 	}
93 
94 	fe = (struct ocfs2_dinode *) (*bh)->b_data;
95 	link = (char *) fe->id2.i_symlink;
96 bail:
97 	mlog_exit(status);
98 
99 	return link;
100 }
101 
102 static int ocfs2_readlink(struct dentry *dentry,
103 			  char __user *buffer,
104 			  int buflen)
105 {
106 	int ret;
107 	char *link;
108 	struct buffer_head *bh = NULL;
109 	struct inode *inode = dentry->d_inode;
110 
111 	mlog_entry_void();
112 
113 	link = ocfs2_fast_symlink_getlink(inode, &bh);
114 	if (IS_ERR(link)) {
115 		ret = PTR_ERR(link);
116 		goto out;
117 	}
118 
119 	/*
120 	 * Without vfsmount we can't update atime now,
121 	 * but we will update atime here ultimately.
122 	 */
123 	ret = vfs_readlink(dentry, buffer, buflen, link);
124 
125 	brelse(bh);
126 out:
127 	mlog_exit(ret);
128 	return ret;
129 }
130 
131 static void *ocfs2_follow_link(struct dentry *dentry,
132 			       struct nameidata *nd)
133 {
134 	int status;
135 	char *link;
136 	struct inode *inode = dentry->d_inode;
137 	struct page *page = NULL;
138 	struct buffer_head *bh = NULL;
139 
140 	if (ocfs2_inode_is_fast_symlink(inode))
141 		link = ocfs2_fast_symlink_getlink(inode, &bh);
142 	else
143 		link = ocfs2_page_getlink(dentry, &page);
144 	if (IS_ERR(link)) {
145 		status = PTR_ERR(link);
146 		mlog_errno(status);
147 		goto bail;
148 	}
149 
150 	status = vfs_follow_link(nd, link);
151 
152 bail:
153 	if (page) {
154 		kunmap(page);
155 		page_cache_release(page);
156 	}
157 	brelse(bh);
158 
159 	return ERR_PTR(status);
160 }
161 
162 const struct inode_operations ocfs2_symlink_inode_operations = {
163 	.readlink	= page_readlink,
164 	.follow_link	= ocfs2_follow_link,
165 	.getattr	= ocfs2_getattr,
166 	.setattr	= ocfs2_setattr,
167 	.setxattr	= generic_setxattr,
168 	.getxattr	= generic_getxattr,
169 	.listxattr	= ocfs2_listxattr,
170 	.removexattr	= generic_removexattr,
171 };
172 const struct inode_operations ocfs2_fast_symlink_inode_operations = {
173 	.readlink	= ocfs2_readlink,
174 	.follow_link	= ocfs2_follow_link,
175 	.getattr	= ocfs2_getattr,
176 	.setattr	= ocfs2_setattr,
177 	.setxattr	= generic_setxattr,
178 	.getxattr	= generic_getxattr,
179 	.listxattr	= ocfs2_listxattr,
180 	.removexattr	= generic_removexattr,
181 };
182