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1da177e4 | 1 | /* |
7b718769 NS |
2 | * Copyright (c) 2004-2005 Silicon Graphics, Inc. |
3 | * All Rights Reserved. | |
1da177e4 | 4 | * |
7b718769 NS |
5 | * This program is free software; you can redistribute it and/or |
6 | * modify it under the terms of the GNU General Public License as | |
1da177e4 LT |
7 | * published by the Free Software Foundation. |
8 | * | |
7b718769 NS |
9 | * This program is distributed in the hope that it would be useful, |
10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
12 | * GNU General Public License for more details. | |
1da177e4 | 13 | * |
7b718769 NS |
14 | * You should have received a copy of the GNU General Public License |
15 | * along with this program; if not, write the Free Software Foundation, | |
16 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA | |
1da177e4 | 17 | */ |
1da177e4 LT |
18 | #include "xfs.h" |
19 | #include "xfs_types.h" | |
20 | #include "xfs_dmapi.h" | |
21 | #include "xfs_log.h" | |
22 | #include "xfs_trans.h" | |
23 | #include "xfs_sb.h" | |
24 | #include "xfs_dir.h" | |
25 | #include "xfs_mount.h" | |
26 | #include "xfs_export.h" | |
27 | ||
9b94c2ed NS |
28 | STATIC struct dentry dotdot = { .d_name.name = "..", .d_name.len = 2, }; |
29 | ||
1da177e4 | 30 | /* |
7b718769 | 31 | * XFS encodes and decodes the fileid portion of NFS filehandles |
1da177e4 LT |
32 | * itself instead of letting the generic NFS code do it. This |
33 | * allows filesystems with 64 bit inode numbers to be exported. | |
34 | * | |
35 | * Note that a side effect is that xfs_vget() won't be passed a | |
36 | * zero inode/generation pair under normal circumstances. As | |
37 | * however a malicious client could send us such data, the check | |
38 | * remains in that code. | |
39 | */ | |
40 | ||
1da177e4 LT |
41 | STATIC struct dentry * |
42 | linvfs_decode_fh( | |
43 | struct super_block *sb, | |
44 | __u32 *fh, | |
45 | int fh_len, | |
46 | int fileid_type, | |
47 | int (*acceptable)( | |
48 | void *context, | |
49 | struct dentry *de), | |
50 | void *context) | |
51 | { | |
52 | xfs_fid2_t ifid; | |
53 | xfs_fid2_t pfid; | |
54 | void *parent = NULL; | |
55 | int is64 = 0; | |
56 | __u32 *p = fh; | |
57 | ||
58 | #if XFS_BIG_INUMS | |
59 | is64 = (fileid_type & XFS_FILEID_TYPE_64FLAG); | |
60 | fileid_type &= ~XFS_FILEID_TYPE_64FLAG; | |
61 | #endif | |
62 | ||
63 | /* | |
64 | * Note that we only accept fileids which are long enough | |
65 | * rather than allow the parent generation number to default | |
66 | * to zero. XFS considers zero a valid generation number not | |
67 | * an invalid/wildcard value. There's little point printk'ing | |
68 | * a warning here as we don't have the client information | |
69 | * which would make such a warning useful. | |
70 | */ | |
71 | if (fileid_type > 2 || | |
72 | fh_len < xfs_fileid_length((fileid_type == 2), is64)) | |
73 | return NULL; | |
74 | ||
75 | p = xfs_fileid_decode_fid2(p, &ifid, is64); | |
76 | ||
77 | if (fileid_type == 2) { | |
78 | p = xfs_fileid_decode_fid2(p, &pfid, is64); | |
79 | parent = &pfid; | |
80 | } | |
7b718769 | 81 | |
1da177e4 | 82 | fh = (__u32 *)&ifid; |
0c9512d7 | 83 | return sb->s_export_op->find_exported_dentry(sb, fh, parent, acceptable, context); |
1da177e4 LT |
84 | } |
85 | ||
86 | ||
87 | STATIC int | |
88 | linvfs_encode_fh( | |
89 | struct dentry *dentry, | |
90 | __u32 *fh, | |
91 | int *max_len, | |
92 | int connectable) | |
93 | { | |
94 | struct inode *inode = dentry->d_inode; | |
95 | int type = 1; | |
96 | __u32 *p = fh; | |
97 | int len; | |
98 | int is64 = 0; | |
99 | #if XFS_BIG_INUMS | |
100 | vfs_t *vfs = LINVFS_GET_VFS(inode->i_sb); | |
7b718769 | 101 | |
c11e2c36 | 102 | if (!(vfs->vfs_flag & VFS_32BITINODES)) { |
1da177e4 LT |
103 | /* filesystem may contain 64bit inode numbers */ |
104 | is64 = XFS_FILEID_TYPE_64FLAG; | |
105 | } | |
106 | #endif | |
107 | ||
108 | /* Directories don't need their parent encoded, they have ".." */ | |
109 | if (S_ISDIR(inode->i_mode)) | |
110 | connectable = 0; | |
111 | ||
112 | /* | |
113 | * Only encode if there is enough space given. In practice | |
114 | * this means we can't export a filesystem with 64bit inodes | |
115 | * over NFSv2 with the subtree_check export option; the other | |
116 | * seven combinations work. The real answer is "don't use v2". | |
117 | */ | |
118 | len = xfs_fileid_length(connectable, is64); | |
119 | if (*max_len < len) | |
120 | return 255; | |
121 | *max_len = len; | |
122 | ||
123 | p = xfs_fileid_encode_inode(p, inode, is64); | |
124 | if (connectable) { | |
125 | spin_lock(&dentry->d_lock); | |
126 | p = xfs_fileid_encode_inode(p, dentry->d_parent->d_inode, is64); | |
127 | spin_unlock(&dentry->d_lock); | |
128 | type = 2; | |
129 | } | |
130 | BUG_ON((p - fh) != len); | |
131 | return type | is64; | |
132 | } | |
133 | ||
134 | STATIC struct dentry * | |
135 | linvfs_get_dentry( | |
136 | struct super_block *sb, | |
137 | void *data) | |
138 | { | |
139 | vnode_t *vp; | |
140 | struct inode *inode; | |
141 | struct dentry *result; | |
142 | vfs_t *vfsp = LINVFS_GET_VFS(sb); | |
143 | int error; | |
144 | ||
145 | VFS_VGET(vfsp, &vp, (fid_t *)data, error); | |
146 | if (error || vp == NULL) | |
147 | return ERR_PTR(-ESTALE) ; | |
148 | ||
149 | inode = LINVFS_GET_IP(vp); | |
150 | result = d_alloc_anon(inode); | |
151 | if (!result) { | |
152 | iput(inode); | |
153 | return ERR_PTR(-ENOMEM); | |
154 | } | |
155 | return result; | |
156 | } | |
157 | ||
158 | STATIC struct dentry * | |
159 | linvfs_get_parent( | |
160 | struct dentry *child) | |
161 | { | |
162 | int error; | |
163 | vnode_t *vp, *cvp; | |
164 | struct dentry *parent; | |
1da177e4 LT |
165 | |
166 | cvp = NULL; | |
167 | vp = LINVFS_GET_VP(child->d_inode); | |
168 | VOP_LOOKUP(vp, &dotdot, &cvp, 0, NULL, NULL, error); | |
169 | if (unlikely(error)) | |
170 | return ERR_PTR(-error); | |
171 | ||
172 | parent = d_alloc_anon(LINVFS_GET_IP(cvp)); | |
173 | if (unlikely(!parent)) { | |
174 | VN_RELE(cvp); | |
175 | return ERR_PTR(-ENOMEM); | |
176 | } | |
177 | return parent; | |
178 | } | |
179 | ||
180 | struct export_operations linvfs_export_ops = { | |
181 | .decode_fh = linvfs_decode_fh, | |
182 | .encode_fh = linvfs_encode_fh, | |
183 | .get_parent = linvfs_get_parent, | |
184 | .get_dentry = linvfs_get_dentry, | |
185 | }; |