1 /*
2 * Copyright (c) 2004-2005 Silicon Graphics, Inc.
3 * All Rights Reserved.
4 *
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
7 * published by the Free Software Foundation.
8 *
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.
13 *
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
17 */
18 #include "xfs.h"
19 #include "xfs_types.h"
20 #include "xfs_inum.h"
21 #include "xfs_log.h"
22 #include "xfs_trans.h"
23 #include "xfs_sb.h"
24 #include "xfs_ag.h"
25 #include "xfs_dir2.h"
26 #include "xfs_dmapi.h"
27 #include "xfs_mount.h"
28 #include "xfs_export.h"
29 #include "xfs_vnodeops.h"
30 #include "xfs_bmap_btree.h"
31 #include "xfs_inode.h"
32
33 /*
34 * Note that we only accept fileids which are long enough rather than allow
35 * the parent generation number to default to zero. XFS considers zero a
36 * valid generation number not an invalid/wildcard value.
37 */
xfs_fileid_length(int fileid_type)38 static int xfs_fileid_length(int fileid_type)
39 {
40 switch (fileid_type) {
41 case FILEID_INO32_GEN:
42 return 2;
43 case FILEID_INO32_GEN_PARENT:
44 return 4;
45 case FILEID_INO32_GEN | XFS_FILEID_TYPE_64FLAG:
46 return 3;
47 case FILEID_INO32_GEN_PARENT | XFS_FILEID_TYPE_64FLAG:
48 return 6;
49 }
50 return 255; /* invalid */
51 }
52
53 STATIC int
xfs_fs_encode_fh(struct dentry * dentry,__u32 * fh,int * max_len,int connectable)54 xfs_fs_encode_fh(
55 struct dentry *dentry,
56 __u32 *fh,
57 int *max_len,
58 int connectable)
59 {
60 struct fid *fid = (struct fid *)fh;
61 struct xfs_fid64 *fid64 = (struct xfs_fid64 *)fh;
62 struct inode *inode = dentry->d_inode;
63 int fileid_type;
64 int len;
65
66 /* Directories don't need their parent encoded, they have ".." */
67 if (S_ISDIR(inode->i_mode) || !connectable)
68 fileid_type = FILEID_INO32_GEN;
69 else
70 fileid_type = FILEID_INO32_GEN_PARENT;
71
72 /* filesystem may contain 64bit inode numbers */
73 if (!(XFS_M(inode->i_sb)->m_flags & XFS_MOUNT_SMALL_INUMS))
74 fileid_type |= XFS_FILEID_TYPE_64FLAG;
75
76 /*
77 * Only encode if there is enough space given. In practice
78 * this means we can't export a filesystem with 64bit inodes
79 * over NFSv2 with the subtree_check export option; the other
80 * seven combinations work. The real answer is "don't use v2".
81 */
82 len = xfs_fileid_length(fileid_type);
83 if (*max_len < len)
84 return 255;
85 *max_len = len;
86
87 switch (fileid_type) {
88 case FILEID_INO32_GEN_PARENT:
89 spin_lock(&dentry->d_lock);
90 fid->i32.parent_ino = dentry->d_parent->d_inode->i_ino;
91 fid->i32.parent_gen = dentry->d_parent->d_inode->i_generation;
92 spin_unlock(&dentry->d_lock);
93 /*FALLTHRU*/
94 case FILEID_INO32_GEN:
95 fid->i32.ino = inode->i_ino;
96 fid->i32.gen = inode->i_generation;
97 break;
98 case FILEID_INO32_GEN_PARENT | XFS_FILEID_TYPE_64FLAG:
99 spin_lock(&dentry->d_lock);
100 fid64->parent_ino = dentry->d_parent->d_inode->i_ino;
101 fid64->parent_gen = dentry->d_parent->d_inode->i_generation;
102 spin_unlock(&dentry->d_lock);
103 /*FALLTHRU*/
104 case FILEID_INO32_GEN | XFS_FILEID_TYPE_64FLAG:
105 fid64->ino = inode->i_ino;
106 fid64->gen = inode->i_generation;
107 break;
108 }
109
110 return fileid_type;
111 }
112
113 STATIC struct inode *
xfs_nfs_get_inode(struct super_block * sb,u64 ino,u32 generation)114 xfs_nfs_get_inode(
115 struct super_block *sb,
116 u64 ino,
117 u32 generation)
118 {
119 xfs_mount_t *mp = XFS_M(sb);
120 xfs_inode_t *ip;
121 int error;
122
123 /*
124 * NFS can sometimes send requests for ino 0. Fail them gracefully.
125 */
126 if (ino == 0)
127 return ERR_PTR(-ESTALE);
128
129 /*
130 * The XFS_IGET_BULKSTAT means that an invalid inode number is just
131 * fine and not an indication of a corrupted filesystem. Because
132 * clients can send any kind of invalid file handle, e.g. after
133 * a restore on the server we have to deal with this case gracefully.
134 */
135 error = xfs_iget(mp, NULL, ino, XFS_IGET_BULKSTAT,
136 XFS_ILOCK_SHARED, &ip, 0);
137 if (error) {
138 /*
139 * EINVAL means the inode cluster doesn't exist anymore.
140 * This implies the filehandle is stale, so we should
141 * translate it here.
142 * We don't use ESTALE directly down the chain to not
143 * confuse applications using bulkstat that expect EINVAL.
144 */
145 if (error == EINVAL)
146 error = ESTALE;
147 return ERR_PTR(-error);
148 }
149
150 if (ip->i_d.di_gen != generation) {
151 xfs_iput_new(ip, XFS_ILOCK_SHARED);
152 return ERR_PTR(-ENOENT);
153 }
154
155 xfs_iunlock(ip, XFS_ILOCK_SHARED);
156 return VFS_I(ip);
157 }
158
159 STATIC struct dentry *
xfs_fs_fh_to_dentry(struct super_block * sb,struct fid * fid,int fh_len,int fileid_type)160 xfs_fs_fh_to_dentry(struct super_block *sb, struct fid *fid,
161 int fh_len, int fileid_type)
162 {
163 struct xfs_fid64 *fid64 = (struct xfs_fid64 *)fid;
164 struct inode *inode = NULL;
165
166 if (fh_len < xfs_fileid_length(fileid_type))
167 return NULL;
168
169 switch (fileid_type) {
170 case FILEID_INO32_GEN_PARENT:
171 case FILEID_INO32_GEN:
172 inode = xfs_nfs_get_inode(sb, fid->i32.ino, fid->i32.gen);
173 break;
174 case FILEID_INO32_GEN_PARENT | XFS_FILEID_TYPE_64FLAG:
175 case FILEID_INO32_GEN | XFS_FILEID_TYPE_64FLAG:
176 inode = xfs_nfs_get_inode(sb, fid64->ino, fid64->gen);
177 break;
178 }
179
180 return d_obtain_alias(inode);
181 }
182
183 STATIC struct dentry *
xfs_fs_fh_to_parent(struct super_block * sb,struct fid * fid,int fh_len,int fileid_type)184 xfs_fs_fh_to_parent(struct super_block *sb, struct fid *fid,
185 int fh_len, int fileid_type)
186 {
187 struct xfs_fid64 *fid64 = (struct xfs_fid64 *)fid;
188 struct inode *inode = NULL;
189
190 switch (fileid_type) {
191 case FILEID_INO32_GEN_PARENT:
192 inode = xfs_nfs_get_inode(sb, fid->i32.parent_ino,
193 fid->i32.parent_gen);
194 break;
195 case FILEID_INO32_GEN_PARENT | XFS_FILEID_TYPE_64FLAG:
196 inode = xfs_nfs_get_inode(sb, fid64->parent_ino,
197 fid64->parent_gen);
198 break;
199 }
200
201 return d_obtain_alias(inode);
202 }
203
204 STATIC struct dentry *
xfs_fs_get_parent(struct dentry * child)205 xfs_fs_get_parent(
206 struct dentry *child)
207 {
208 int error;
209 struct xfs_inode *cip;
210
211 error = xfs_lookup(XFS_I(child->d_inode), &xfs_name_dotdot, &cip, NULL);
212 if (unlikely(error))
213 return ERR_PTR(-error);
214
215 return d_obtain_alias(VFS_I(cip));
216 }
217
218 const struct export_operations xfs_export_operations = {
219 .encode_fh = xfs_fs_encode_fh,
220 .fh_to_dentry = xfs_fs_fh_to_dentry,
221 .fh_to_parent = xfs_fs_fh_to_parent,
222 .get_parent = xfs_fs_get_parent,
223 };
224