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#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
58static char *ocfs2_fast_symlink_getlink(struct inode *inode,
59                    struct buffer_head **bh)
60{
61    int status;
62    char *link = NULL;
63    struct ocfs2_dinode *fe;
64
65    mlog_entry_void();
66
67    status = ocfs2_read_inode_block(inode, bh);
68    if (status < 0) {
69        mlog_errno(status);
70        link = ERR_PTR(status);
71        goto bail;
72    }
73
74    fe = (struct ocfs2_dinode *) (*bh)->b_data;
75    link = (char *) fe->id2.i_symlink;
76bail:
77    mlog_exit(status);
78
79    return link;
80}
81
82static int ocfs2_readlink(struct dentry *dentry,
83              char __user *buffer,
84              int buflen)
85{
86    int ret;
87    char *link;
88    struct buffer_head *bh = NULL;
89    struct inode *inode = dentry->d_inode;
90
91    mlog_entry_void();
92
93    link = ocfs2_fast_symlink_getlink(inode, &bh);
94    if (IS_ERR(link)) {
95        ret = PTR_ERR(link);
96        goto out;
97    }
98
99    /*
100     * Without vfsmount we can't update atime now,
101     * but we will update atime here ultimately.
102     */
103    ret = vfs_readlink(dentry, buffer, buflen, link);
104
105    brelse(bh);
106out:
107    mlog_exit(ret);
108    return ret;
109}
110
111static void *ocfs2_fast_follow_link(struct dentry *dentry,
112                    struct nameidata *nd)
113{
114    int status = 0;
115    int len;
116    char *target, *link = ERR_PTR(-ENOMEM);
117    struct inode *inode = dentry->d_inode;
118    struct buffer_head *bh = NULL;
119
120    mlog_entry_void();
121
122    BUG_ON(!ocfs2_inode_is_fast_symlink(inode));
123    target = ocfs2_fast_symlink_getlink(inode, &bh);
124    if (IS_ERR(target)) {
125        status = PTR_ERR(target);
126        mlog_errno(status);
127        goto bail;
128    }
129
130    /* Fast symlinks can't be large */
131    len = strlen(target);
132    link = kzalloc(len + 1, GFP_NOFS);
133    if (!link) {
134        status = -ENOMEM;
135        mlog_errno(status);
136        goto bail;
137    }
138
139    memcpy(link, target, len);
140
141bail:
142    nd_set_link(nd, status ? ERR_PTR(status) : link);
143    brelse(bh);
144
145    mlog_exit(status);
146    return NULL;
147}
148
149static void ocfs2_fast_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie)
150{
151    char *link = nd_get_link(nd);
152    if (!IS_ERR(link))
153        kfree(link);
154}
155
156const struct inode_operations ocfs2_symlink_inode_operations = {
157    .readlink = page_readlink,
158    .follow_link = page_follow_link_light,
159    .put_link = page_put_link,
160    .getattr = ocfs2_getattr,
161    .setattr = ocfs2_setattr,
162    .setxattr = generic_setxattr,
163    .getxattr = generic_getxattr,
164    .listxattr = ocfs2_listxattr,
165    .removexattr = generic_removexattr,
166    .fiemap = ocfs2_fiemap,
167};
168const 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    .fiemap = ocfs2_fiemap,
179};
180

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