Line data Source code
1 : // SPDX-License-Identifier: GPL-2.0
2 : /*
3 : * Copyright (c) 2004-2005 Silicon Graphics, Inc.
4 : * All Rights Reserved.
5 : */
6 : #include "xfs.h"
7 : #include "xfs_shared.h"
8 : #include "xfs_format.h"
9 : #include "xfs_log_format.h"
10 : #include "xfs_trans_resv.h"
11 : #include "xfs_mount.h"
12 : #include "xfs_dir2.h"
13 : #include "xfs_export.h"
14 : #include "xfs_inode.h"
15 : #include "xfs_trans.h"
16 : #include "xfs_inode_item.h"
17 : #include "xfs_icache.h"
18 : #include "xfs_pnfs.h"
19 :
20 : /*
21 : * Note that we only accept fileids which are long enough rather than allow
22 : * the parent generation number to default to zero. XFS considers zero a
23 : * valid generation number not an invalid/wildcard value.
24 : */
25 191556313 : static int xfs_fileid_length(int fileid_type)
26 : {
27 191556313 : switch (fileid_type) {
28 : case FILEID_INO32_GEN:
29 : return 2;
30 0 : case FILEID_INO32_GEN_PARENT:
31 0 : return 4;
32 191556313 : case FILEID_INO32_GEN | XFS_FILEID_TYPE_64FLAG:
33 191556313 : return 3;
34 0 : case FILEID_INO32_GEN_PARENT | XFS_FILEID_TYPE_64FLAG:
35 0 : return 6;
36 : }
37 0 : return FILEID_INVALID;
38 : }
39 :
40 : STATIC int
41 31820 : xfs_fs_encode_fh(
42 : struct inode *inode,
43 : __u32 *fh,
44 : int *max_len,
45 : struct inode *parent)
46 : {
47 31820 : struct xfs_mount *mp = XFS_M(inode->i_sb);
48 31820 : struct fid *fid = (struct fid *)fh;
49 31820 : struct xfs_fid64 *fid64 = (struct xfs_fid64 *)fh;
50 31820 : int fileid_type;
51 31820 : int len;
52 :
53 : /* Directories don't need their parent encoded, they have ".." */
54 31820 : if (!parent)
55 : fileid_type = FILEID_INO32_GEN;
56 : else
57 0 : fileid_type = FILEID_INO32_GEN_PARENT;
58 :
59 : /*
60 : * If the filesystem may contain 64bit inode numbers, we need
61 : * to use larger file handles that can represent them.
62 : *
63 : * While we only allocate inodes that do not fit into 32 bits any
64 : * large enough filesystem may contain them, thus the slightly
65 : * confusing looking conditional below.
66 : */
67 31820 : if (!xfs_has_small_inums(mp) || xfs_is_inode32(mp))
68 31820 : fileid_type |= XFS_FILEID_TYPE_64FLAG;
69 :
70 : /*
71 : * Only encode if there is enough space given. In practice
72 : * this means we can't export a filesystem with 64bit inodes
73 : * over NFSv2 with the subtree_check export option; the other
74 : * seven combinations work. The real answer is "don't use v2".
75 : */
76 31820 : len = xfs_fileid_length(fileid_type);
77 31820 : if (*max_len < len) {
78 0 : *max_len = len;
79 0 : return FILEID_INVALID;
80 : }
81 31820 : *max_len = len;
82 :
83 31820 : switch (fileid_type) {
84 : case FILEID_INO32_GEN_PARENT:
85 0 : fid->i32.parent_ino = XFS_I(parent)->i_ino;
86 0 : fid->i32.parent_gen = parent->i_generation;
87 0 : fallthrough;
88 0 : case FILEID_INO32_GEN:
89 0 : fid->i32.ino = XFS_I(inode)->i_ino;
90 0 : fid->i32.gen = inode->i_generation;
91 0 : break;
92 : case FILEID_INO32_GEN_PARENT | XFS_FILEID_TYPE_64FLAG:
93 0 : fid64->parent_ino = XFS_I(parent)->i_ino;
94 0 : fid64->parent_gen = parent->i_generation;
95 31820 : fallthrough;
96 31820 : case FILEID_INO32_GEN | XFS_FILEID_TYPE_64FLAG:
97 31820 : fid64->ino = XFS_I(inode)->i_ino;
98 31820 : fid64->gen = inode->i_generation;
99 31820 : break;
100 : }
101 :
102 : return fileid_type;
103 : }
104 :
105 : STATIC struct inode *
106 191525406 : xfs_nfs_get_inode(
107 : struct super_block *sb,
108 : u64 ino,
109 : u32 generation)
110 : {
111 191525406 : xfs_mount_t *mp = XFS_M(sb);
112 191525406 : xfs_inode_t *ip;
113 191525406 : int error;
114 :
115 : /*
116 : * NFS can sometimes send requests for ino 0. Fail them gracefully.
117 : */
118 191525406 : if (ino == 0)
119 : return ERR_PTR(-ESTALE);
120 :
121 : /*
122 : * The XFS_IGET_UNTRUSTED means that an invalid inode number is just
123 : * fine and not an indication of a corrupted filesystem as clients can
124 : * send invalid file handles and we have to handle it gracefully..
125 : */
126 191527337 : error = xfs_iget(mp, NULL, ino, XFS_IGET_UNTRUSTED, 0, &ip);
127 191527493 : if (error) {
128 :
129 : /*
130 : * EINVAL means the inode cluster doesn't exist anymore.
131 : * EFSCORRUPTED means the metadata pointing to the inode cluster
132 : * or the inode cluster itself is corrupt. This implies the
133 : * filehandle is stale, so we should translate it here.
134 : * We don't use ESTALE directly down the chain to not
135 : * confuse applications using bulkstat that expect EINVAL.
136 : */
137 4312 : switch (error) {
138 4312 : case -EINVAL:
139 : case -ENOENT:
140 : case -EFSCORRUPTED:
141 4312 : error = -ESTALE;
142 4312 : break;
143 : default:
144 : break;
145 : }
146 4312 : return ERR_PTR(error);
147 : }
148 :
149 191523181 : if (VFS_I(ip)->i_generation != generation || IS_PRIVATE(VFS_I(ip))) {
150 56 : xfs_irele(ip);
151 56 : return ERR_PTR(-ESTALE);
152 : }
153 :
154 191523125 : return VFS_I(ip);
155 : }
156 :
157 : STATIC struct dentry *
158 191525412 : xfs_fs_fh_to_dentry(struct super_block *sb, struct fid *fid,
159 : int fh_len, int fileid_type)
160 : {
161 191525412 : struct xfs_fid64 *fid64 = (struct xfs_fid64 *)fid;
162 191525412 : struct inode *inode = NULL;
163 :
164 191525412 : if (fh_len < xfs_fileid_length(fileid_type))
165 : return NULL;
166 :
167 191525412 : switch (fileid_type) {
168 0 : case FILEID_INO32_GEN_PARENT:
169 : case FILEID_INO32_GEN:
170 0 : inode = xfs_nfs_get_inode(sb, fid->i32.ino, fid->i32.gen);
171 0 : break;
172 191525412 : case FILEID_INO32_GEN_PARENT | XFS_FILEID_TYPE_64FLAG:
173 : case FILEID_INO32_GEN | XFS_FILEID_TYPE_64FLAG:
174 191525412 : inode = xfs_nfs_get_inode(sb, fid64->ino, fid64->gen);
175 191525412 : break;
176 : }
177 :
178 191529828 : return d_obtain_alias(inode);
179 : }
180 :
181 : STATIC struct dentry *
182 0 : xfs_fs_fh_to_parent(struct super_block *sb, struct fid *fid,
183 : int fh_len, int fileid_type)
184 : {
185 0 : struct xfs_fid64 *fid64 = (struct xfs_fid64 *)fid;
186 0 : struct inode *inode = NULL;
187 :
188 0 : if (fh_len < xfs_fileid_length(fileid_type))
189 : return NULL;
190 :
191 0 : switch (fileid_type) {
192 0 : case FILEID_INO32_GEN_PARENT:
193 0 : inode = xfs_nfs_get_inode(sb, fid->i32.parent_ino,
194 : fid->i32.parent_gen);
195 0 : break;
196 0 : case FILEID_INO32_GEN_PARENT | XFS_FILEID_TYPE_64FLAG:
197 0 : inode = xfs_nfs_get_inode(sb, fid64->parent_ino,
198 : fid64->parent_gen);
199 0 : break;
200 : }
201 :
202 0 : return d_obtain_alias(inode);
203 : }
204 :
205 : STATIC struct dentry *
206 2850711 : xfs_fs_get_parent(
207 : struct dentry *child)
208 : {
209 2850711 : int error;
210 2850711 : struct xfs_inode *cip;
211 :
212 2850711 : error = xfs_lookup(XFS_I(d_inode(child)), &xfs_name_dotdot, &cip, NULL);
213 2850727 : if (unlikely(error))
214 0 : return ERR_PTR(error);
215 :
216 2850727 : return d_obtain_alias(VFS_I(cip));
217 : }
218 :
219 : STATIC int
220 0 : xfs_fs_nfs_commit_metadata(
221 : struct inode *inode)
222 : {
223 0 : return xfs_log_force_inode(XFS_I(inode));
224 : }
225 :
226 : const struct export_operations xfs_export_operations = {
227 : .encode_fh = xfs_fs_encode_fh,
228 : .fh_to_dentry = xfs_fs_fh_to_dentry,
229 : .fh_to_parent = xfs_fs_fh_to_parent,
230 : .get_parent = xfs_fs_get_parent,
231 : .commit_metadata = xfs_fs_nfs_commit_metadata,
232 : #ifdef CONFIG_EXPORTFS_BLOCK_OPS
233 : .get_uuid = xfs_fs_get_uuid,
234 : .map_blocks = xfs_fs_map_blocks,
235 : .commit_blocks = xfs_fs_commit_blocks,
236 : #endif
237 : };
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