Root/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/namei.h>
42
43#include <cluster/masklog.h>
44
45#include "ocfs2.h"
46
47#include "alloc.h"
48#include "file.h"
49#include "inode.h"
50#include "journal.h"
51#include "symlink.h"
52#include "xattr.h"
53
54#include "buffer_head_io.h"
55
56
57static char *ocfs2_fast_symlink_getlink(struct inode *inode,
58                    struct buffer_head **bh)
59{
60    int status;
61    char *link = NULL;
62    struct ocfs2_dinode *fe;
63
64    status = ocfs2_read_inode_block(inode, bh);
65    if (status < 0) {
66        mlog_errno(status);
67        link = ERR_PTR(status);
68        goto bail;
69    }
70
71    fe = (struct ocfs2_dinode *) (*bh)->b_data;
72    link = (char *) fe->id2.i_symlink;
73bail:
74
75    return link;
76}
77
78static int ocfs2_readlink(struct dentry *dentry,
79              char __user *buffer,
80              int buflen)
81{
82    int ret;
83    char *link;
84    struct buffer_head *bh = NULL;
85    struct inode *inode = dentry->d_inode;
86
87    link = ocfs2_fast_symlink_getlink(inode, &bh);
88    if (IS_ERR(link)) {
89        ret = PTR_ERR(link);
90        goto out;
91    }
92
93    /*
94     * Without vfsmount we can't update atime now,
95     * but we will update atime here ultimately.
96     */
97    ret = vfs_readlink(dentry, buffer, buflen, link);
98
99    brelse(bh);
100out:
101    if (ret < 0)
102        mlog_errno(ret);
103    return ret;
104}
105
106static void *ocfs2_fast_follow_link(struct dentry *dentry,
107                    struct nameidata *nd)
108{
109    int status = 0;
110    int len;
111    char *target, *link = ERR_PTR(-ENOMEM);
112    struct inode *inode = dentry->d_inode;
113    struct buffer_head *bh = NULL;
114
115    BUG_ON(!ocfs2_inode_is_fast_symlink(inode));
116    target = ocfs2_fast_symlink_getlink(inode, &bh);
117    if (IS_ERR(target)) {
118        status = PTR_ERR(target);
119        mlog_errno(status);
120        goto bail;
121    }
122
123    /* Fast symlinks can't be large */
124    len = strnlen(target, ocfs2_fast_symlink_chars(inode->i_sb));
125    link = kzalloc(len + 1, GFP_NOFS);
126    if (!link) {
127        status = -ENOMEM;
128        mlog_errno(status);
129        goto bail;
130    }
131
132    memcpy(link, target, len);
133
134bail:
135    nd_set_link(nd, status ? ERR_PTR(status) : link);
136    brelse(bh);
137
138    if (status)
139        mlog_errno(status);
140    return NULL;
141}
142
143static void ocfs2_fast_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie)
144{
145    char *link = nd_get_link(nd);
146    if (!IS_ERR(link))
147        kfree(link);
148}
149
150const struct inode_operations ocfs2_symlink_inode_operations = {
151    .readlink = page_readlink,
152    .follow_link = page_follow_link_light,
153    .put_link = page_put_link,
154    .getattr = ocfs2_getattr,
155    .setattr = ocfs2_setattr,
156    .setxattr = generic_setxattr,
157    .getxattr = generic_getxattr,
158    .listxattr = ocfs2_listxattr,
159    .removexattr = generic_removexattr,
160    .fiemap = ocfs2_fiemap,
161};
162const struct inode_operations ocfs2_fast_symlink_inode_operations = {
163    .readlink = ocfs2_readlink,
164    .follow_link = ocfs2_fast_follow_link,
165    .put_link = ocfs2_fast_put_link,
166    .getattr = ocfs2_getattr,
167    .setattr = ocfs2_setattr,
168    .setxattr = generic_setxattr,
169    .getxattr = generic_getxattr,
170    .listxattr = ocfs2_listxattr,
171    .removexattr = generic_removexattr,
172    .fiemap = ocfs2_fiemap,
173};
174

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