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
56 static char *ocfs2_page_getlink(struct dentry * dentry,
57 struct page **ppage);
58 static char *ocfs2_fast_symlink_getlink(struct inode *inode,
59 struct buffer_head **bh);
60
61 /* get the link contents into pagecache */
62 static 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
73 sync_fail:
74 return (char*)page;
75 }
76
77 static 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;
99 bail:
100 mlog_exit(status);
101
102 return link;
103 }
104
105 static 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);
129 out:
130 mlog_exit(ret);
131 return ret;
132 }
133
134 static 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
155 bail:
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
166 const struct inode_operations ocfs2_symlink_inode_operations = {
167 .readlink = page_readlink,
168 .follow_link = ocfs2_follow_link,
169 .getattr = ocfs2_getattr,
170 };
171 const struct inode_operations ocfs2_fast_symlink_inode_operations = {
172 .readlink = ocfs2_readlink,
173 .follow_link = ocfs2_follow_link,
174 .getattr = ocfs2_getattr,
175 };
176
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