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diff --git a/fs/xfs/linux-2.6/xfs_export.c b/fs/xfs/linux-2.6/xfs_export.c
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1/*
2 * Copyright (c) 2004-2005 Silicon Graphics, Inc. All Rights Reserved.
3 *
4 * This program is free software; you can redistribute it and/or modify it
5 * under the terms of version 2 of the GNU General Public License as
6 * published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it would be useful, but
9 * WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
11 *
12 * Further, this software is distributed without any warranty that it is
13 * free of the rightful claim of any third person regarding infringement
14 * or the like. Any license provided herein, whether implied or
15 * otherwise, applies only to this software file. Patent licenses, if
16 * any, provided herein do not apply to combinations of this program with
17 * other software, or any other product whatsoever.
18 *
19 * You should have received a copy of the GNU General Public License along
20 * with this program; if not, write the Free Software Foundation, Inc., 59
21 * Temple Place - Suite 330, Boston MA 02111-1307, USA.
22 *
23 * Contact information: Silicon Graphics, Inc., 1600 Amphitheatre Pkwy,
24 * Mountain View, CA 94043, or:
25 *
26 * http://www.sgi.com
27 *
28 * For further information regarding this notice, see:
29 *
30 * http://oss.sgi.com/projects/GenInfo/SGIGPLNoticeExplan/
31 */
32
33#include "xfs.h"
34#include "xfs_types.h"
35#include "xfs_dmapi.h"
36#include "xfs_log.h"
37#include "xfs_trans.h"
38#include "xfs_sb.h"
39#include "xfs_dir.h"
40#include "xfs_mount.h"
41#include "xfs_export.h"
42
43/*
44 * XFS encode and decodes the fileid portion of NFS filehandles
45 * itself instead of letting the generic NFS code do it. This
46 * allows filesystems with 64 bit inode numbers to be exported.
47 *
48 * Note that a side effect is that xfs_vget() won't be passed a
49 * zero inode/generation pair under normal circumstances. As
50 * however a malicious client could send us such data, the check
51 * remains in that code.
52 */
53
54
55STATIC struct dentry *
56linvfs_decode_fh(
57 struct super_block *sb,
58 __u32 *fh,
59 int fh_len,
60 int fileid_type,
61 int (*acceptable)(
62 void *context,
63 struct dentry *de),
64 void *context)
65{
66 xfs_fid2_t ifid;
67 xfs_fid2_t pfid;
68 void *parent = NULL;
69 int is64 = 0;
70 __u32 *p = fh;
71
72#if XFS_BIG_INUMS
73 is64 = (fileid_type & XFS_FILEID_TYPE_64FLAG);
74 fileid_type &= ~XFS_FILEID_TYPE_64FLAG;
75#endif
76
77 /*
78 * Note that we only accept fileids which are long enough
79 * rather than allow the parent generation number to default
80 * to zero. XFS considers zero a valid generation number not
81 * an invalid/wildcard value. There's little point printk'ing
82 * a warning here as we don't have the client information
83 * which would make such a warning useful.
84 */
85 if (fileid_type > 2 ||
86 fh_len < xfs_fileid_length((fileid_type == 2), is64))
87 return NULL;
88
89 p = xfs_fileid_decode_fid2(p, &ifid, is64);
90
91 if (fileid_type == 2) {
92 p = xfs_fileid_decode_fid2(p, &pfid, is64);
93 parent = &pfid;
94 }
95
96 fh = (__u32 *)&ifid;
97 return find_exported_dentry(sb, fh, parent, acceptable, context);
98}
99
100
101STATIC int
102linvfs_encode_fh(
103 struct dentry *dentry,
104 __u32 *fh,
105 int *max_len,
106 int connectable)
107{
108 struct inode *inode = dentry->d_inode;
109 int type = 1;
110 __u32 *p = fh;
111 int len;
112 int is64 = 0;
113#if XFS_BIG_INUMS
114 vfs_t *vfs = LINVFS_GET_VFS(inode->i_sb);
115 xfs_mount_t *mp = XFS_VFSTOM(vfs);
116
117 if (!(mp->m_flags & XFS_MOUNT_32BITINOOPT)) {
118 /* filesystem may contain 64bit inode numbers */
119 is64 = XFS_FILEID_TYPE_64FLAG;
120 }
121#endif
122
123 /* Directories don't need their parent encoded, they have ".." */
124 if (S_ISDIR(inode->i_mode))
125 connectable = 0;
126
127 /*
128 * Only encode if there is enough space given. In practice
129 * this means we can't export a filesystem with 64bit inodes
130 * over NFSv2 with the subtree_check export option; the other
131 * seven combinations work. The real answer is "don't use v2".
132 */
133 len = xfs_fileid_length(connectable, is64);
134 if (*max_len < len)
135 return 255;
136 *max_len = len;
137
138 p = xfs_fileid_encode_inode(p, inode, is64);
139 if (connectable) {
140 spin_lock(&dentry->d_lock);
141 p = xfs_fileid_encode_inode(p, dentry->d_parent->d_inode, is64);
142 spin_unlock(&dentry->d_lock);
143 type = 2;
144 }
145 BUG_ON((p - fh) != len);
146 return type | is64;
147}
148
149STATIC struct dentry *
150linvfs_get_dentry(
151 struct super_block *sb,
152 void *data)
153{
154 vnode_t *vp;
155 struct inode *inode;
156 struct dentry *result;
157 vfs_t *vfsp = LINVFS_GET_VFS(sb);
158 int error;
159
160 VFS_VGET(vfsp, &vp, (fid_t *)data, error);
161 if (error || vp == NULL)
162 return ERR_PTR(-ESTALE) ;
163
164 inode = LINVFS_GET_IP(vp);
165 result = d_alloc_anon(inode);
166 if (!result) {
167 iput(inode);
168 return ERR_PTR(-ENOMEM);
169 }
170 return result;
171}
172
173STATIC struct dentry *
174linvfs_get_parent(
175 struct dentry *child)
176{
177 int error;
178 vnode_t *vp, *cvp;
179 struct dentry *parent;
180 struct dentry dotdot;
181
182 dotdot.d_name.name = "..";
183 dotdot.d_name.len = 2;
184 dotdot.d_inode = NULL;
185
186 cvp = NULL;
187 vp = LINVFS_GET_VP(child->d_inode);
188 VOP_LOOKUP(vp, &dotdot, &cvp, 0, NULL, NULL, error);
189 if (unlikely(error))
190 return ERR_PTR(-error);
191
192 parent = d_alloc_anon(LINVFS_GET_IP(cvp));
193 if (unlikely(!parent)) {
194 VN_RELE(cvp);
195 return ERR_PTR(-ENOMEM);
196 }
197 return parent;
198}
199
200struct export_operations linvfs_export_ops = {
201 .decode_fh = linvfs_decode_fh,
202 .encode_fh = linvfs_encode_fh,
203 .get_parent = linvfs_get_parent,
204 .get_dentry = linvfs_get_dentry,
205};
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