Merge branch 'linus' of master.kernel.org:/pub/scm/linux/kernel/git/perex/alsa
[linux-2.6] / fs / ocfs2 / symlink.c
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         wait_on_page_locked(page);
71         if (!PageUptodate(page))
72                 goto async_fail;
73         *ppage = page;
74         return kmap(page);
75
76 async_fail:
77         page_cache_release(page);
78         return ERR_PTR(-EIO);
79
80 sync_fail:
81         return (char*)page;
82 }
83
84 static char *ocfs2_fast_symlink_getlink(struct inode *inode,
85                                         struct buffer_head **bh)
86 {
87         int status;
88         char *link = NULL;
89         struct ocfs2_dinode *fe;
90
91         mlog_entry_void();
92
93         status = ocfs2_read_block(OCFS2_SB(inode->i_sb),
94                                   OCFS2_I(inode)->ip_blkno,
95                                   bh,
96                                   OCFS2_BH_CACHED,
97                                   inode);
98         if (status < 0) {
99                 mlog_errno(status);
100                 link = ERR_PTR(status);
101                 goto bail;
102         }
103
104         fe = (struct ocfs2_dinode *) (*bh)->b_data;
105         link = (char *) fe->id2.i_symlink;
106 bail:
107         mlog_exit(status);
108
109         return link;
110 }
111
112 static int ocfs2_readlink(struct dentry *dentry,
113                           char __user *buffer,
114                           int buflen)
115 {
116         int ret;
117         char *link;
118         struct buffer_head *bh = NULL;
119         struct inode *inode = dentry->d_inode;
120
121         mlog_entry_void();
122
123         link = ocfs2_fast_symlink_getlink(inode, &bh);
124         if (IS_ERR(link)) {
125                 ret = PTR_ERR(link);
126                 goto out;
127         }
128
129         /*
130          * Without vfsmount we can't update atime now,
131          * but we will update atime here ultimately.
132          */
133         ret = vfs_readlink(dentry, buffer, buflen, link);
134
135         brelse(bh);
136 out:
137         mlog_exit(ret);
138         return ret;
139 }
140
141 static void *ocfs2_follow_link(struct dentry *dentry,
142                                struct nameidata *nd)
143 {
144         int status;
145         char *link;
146         struct inode *inode = dentry->d_inode;
147         struct page *page = NULL;
148         struct buffer_head *bh = NULL;
149         
150         if (ocfs2_inode_is_fast_symlink(inode))
151                 link = ocfs2_fast_symlink_getlink(inode, &bh);
152         else
153                 link = ocfs2_page_getlink(dentry, &page);
154         if (IS_ERR(link)) {
155                 status = PTR_ERR(link);
156                 mlog_errno(status);
157                 goto bail;
158         }
159
160         status = vfs_follow_link(nd, link);
161
162 bail:
163         if (page) {
164                 kunmap(page);
165                 page_cache_release(page);
166         }
167         if (bh)
168                 brelse(bh);
169
170         return ERR_PTR(status);
171 }
172
173 const struct inode_operations ocfs2_symlink_inode_operations = {
174         .readlink       = page_readlink,
175         .follow_link    = ocfs2_follow_link,
176         .getattr        = ocfs2_getattr,
177 };
178 const struct inode_operations ocfs2_fast_symlink_inode_operations = {
179         .readlink       = ocfs2_readlink,
180         .follow_link    = ocfs2_follow_link,
181         .getattr        = ocfs2_getattr,
182 };