aboutsummaryrefslogtreecommitdiffstats
path: root/fs/xfs/linux-2.6/xfs_export.c
blob: f372a1a5e1680905b0af3f79a5be43911f7c0c39 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
/*
 * Copyright (c) 2004-2005 Silicon Graphics, Inc.  All Rights Reserved.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of version 2 of the GNU General Public License as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it would be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 *
 * Further, this software is distributed without any warranty that it is
 * free of the rightful claim of any third person regarding infringement
 * or the like.  Any license provided herein, whether implied or
 * otherwise, applies only to this software file.  Patent licenses, if
 * any, provided herein do not apply to combinations of this program with
 * other software, or any other product whatsoever.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write the Free Software Foundation, Inc., 59
 * Temple Place - Suite 330, Boston MA 02111-1307, USA.
 *
 * Contact information: Silicon Graphics, Inc., 1600 Amphitheatre Pkwy,
 * Mountain View, CA  94043, or:
 *
 * http://www.sgi.com
 *
 * For further information regarding this notice, see:
 *
 * http://oss.sgi.com/projects/GenInfo/SGIGPLNoticeExplan/
 */

#include "xfs.h"
#include "xfs_types.h"
#include "xfs_dmapi.h"
#include "xfs_log.h"
#include "xfs_trans.h"
#include "xfs_sb.h"
#include "xfs_dir.h"
#include "xfs_mount.h"
#include "xfs_export.h"

/*
 * XFS encode and decodes the fileid portion of NFS filehandles
 * itself instead of letting the generic NFS code do it.  This
 * allows filesystems with 64 bit inode numbers to be exported.
 *
 * Note that a side effect is that xfs_vget() won't be passed a
 * zero inode/generation pair under normal circumstances.  As
 * however a malicious client could send us such data, the check
 * remains in that code.
 */


STATIC struct dentry *
linvfs_decode_fh(
	struct super_block	*sb,
	__u32			*fh,
	int			fh_len,
	int			fileid_type,
	int (*acceptable)(
		void		*context,
		struct dentry	*de),
	void			*context)
{
	xfs_fid2_t		ifid;
	xfs_fid2_t		pfid;
	void			*parent = NULL;
	int			is64 = 0;
	__u32			*p = fh;

#if XFS_BIG_INUMS
	is64 = (fileid_type & XFS_FILEID_TYPE_64FLAG);
	fileid_type &= ~XFS_FILEID_TYPE_64FLAG;
#endif

	/*
	 * Note that we only accept fileids which are long enough
	 * rather than allow the parent generation number to default
	 * to zero.  XFS considers zero a valid generation number not
	 * an invalid/wildcard value.  There's little point printk'ing
	 * a warning here as we don't have the client information
	 * which would make such a warning useful.
	 */
	if (fileid_type > 2 ||
	    fh_len < xfs_fileid_length((fileid_type == 2), is64))
		return NULL;

	p = xfs_fileid_decode_fid2(p, &ifid, is64);

	if (fileid_type == 2) {
		p = xfs_fileid_decode_fid2(p, &pfid, is64);
		parent = &pfid;
	}
	
	fh = (__u32 *)&ifid;
	return find_exported_dentry(sb, fh, parent, acceptable, context);
}


STATIC int
linvfs_encode_fh(
	struct dentry		*dentry,
	__u32			*fh,
	int			*max_len,
	int			connectable)
{
	struct inode		*inode = dentry->d_inode;
	int			type = 1;
	__u32			*p = fh;
	int			len;
	int			is64 = 0;
#if XFS_BIG_INUMS
	vfs_t			*vfs = LINVFS_GET_VFS(inode->i_sb);
	xfs_mount_t		*mp = XFS_VFSTOM(vfs);
	
	if (!(mp->m_flags & XFS_MOUNT_32BITINOOPT)) {
		/* filesystem may contain 64bit inode numbers */
		is64 = XFS_FILEID_TYPE_64FLAG;
	}
#endif

	/* Directories don't need their parent encoded, they have ".." */
	if (S_ISDIR(inode->i_mode))
	    connectable = 0;

	/*
	 * Only encode if there is enough space given.  In practice
	 * this means we can't export a filesystem with 64bit inodes
	 * over NFSv2 with the subtree_check export option; the other
	 * seven combinations work.  The real answer is "don't use v2".
	 */
	len = xfs_fileid_length(connectable, is64);
	if (*max_len < len)
		return 255;
	*max_len = len;

	p = xfs_fileid_encode_inode(p, inode, is64);
	if (connectable) {
		spin_lock(&dentry->d_lock);
		p = xfs_fileid_encode_inode(p, dentry->d_parent->d_inode, is64);
		spin_unlock(&dentry->d_lock);
		type = 2;
	}
	BUG_ON((p - fh) != len);
	return type | is64;
}

STATIC struct dentry *
linvfs_get_dentry(
	struct super_block	*sb,
	void			*data)
{
	vnode_t			*vp;
	struct inode		*inode;
	struct dentry		*result;
	vfs_t			*vfsp = LINVFS_GET_VFS(sb);
	int			error;

	VFS_VGET(vfsp, &vp, (fid_t *)data, error);
	if (error || vp == NULL)
		return ERR_PTR(-ESTALE) ;

	inode = LINVFS_GET_IP(vp);
	result = d_alloc_anon(inode);
        if (!result) {
		iput(inode);
		return ERR_PTR(-ENOMEM);
	}
	return result;
}

STATIC struct dentry *
linvfs_get_parent(
	struct dentry		*child)
{
	int			error;
	vnode_t			*vp, *cvp;
	struct dentry		*parent;
	struct dentry		dotdot;

	dotdot.d_name.name = "..";
	dotdot.d_name.len = 2;
	dotdot.d_inode = NULL;

	cvp = NULL;
	vp = LINVFS_GET_VP(child->d_inode);
	VOP_LOOKUP(vp, &dotdot, &cvp, 0, NULL, NULL, error);
	if (unlikely(error))
		return ERR_PTR(-error);

	parent = d_alloc_anon(LINVFS_GET_IP(cvp));
	if (unlikely(!parent)) {
		VN_RELE(cvp);
		return ERR_PTR(-ENOMEM);
	}
	return parent;
}

struct export_operations linvfs_export_ops = {
	.decode_fh		= linvfs_decode_fh,
	.encode_fh		= linvfs_encode_fh,
	.get_parent		= linvfs_get_parent,
	.get_dentry		= linvfs_get_dentry,
};