1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright (c) 2015, Primary Data, Inc. All rights reserved.
4 *
5 * Tao Peng <bergwolf@primarydata.com>
6 */
7 #include <linux/dcache.h>
8 #include <linux/exportfs.h>
9 #include <linux/nfs.h>
10 #include <linux/nfs_fs.h>
11
12 #include "internal.h"
13 #include "nfstrace.h"
14
15 #define NFSDBG_FACILITY NFSDBG_VFS
16
17 enum {
18 FILEID_HIGH_OFF = 0, /* inode fileid high */
19 FILEID_LOW_OFF, /* inode fileid low */
20 FILE_I_TYPE_OFF, /* inode type */
21 EMBED_FH_OFF /* embeded server fh */
22 };
23
24
25 static struct nfs_fh *nfs_exp_embedfh(__u32 *p)
26 {
27 return (struct nfs_fh *)(p + EMBED_FH_OFF);
28 }
29
30 /*
31 * Let's break subtree checking for now... otherwise we'll have to embed parent fh
32 * but there might not be enough space.
33 */
34 static int
35 nfs_encode_fh(struct inode *inode, __u32 *p, int *max_len, struct inode *parent)
36 {
37 struct nfs_fh *server_fh = NFS_FH(inode);
38 struct nfs_fh *clnt_fh = nfs_exp_embedfh(p);
39 size_t fh_size = offsetof(struct nfs_fh, data) + server_fh->size;
40 int len = EMBED_FH_OFF + XDR_QUADLEN(fh_size);
41
42 dprintk("%s: max fh len %d inode %p parent %p",
43 __func__, *max_len, inode, parent);
44
45 if (*max_len < len) {
46 dprintk("%s: fh len %d too small, required %d\n",
47 __func__, *max_len, len);
48 *max_len = len;
49 return FILEID_INVALID;
50 }
51
52 p[FILEID_HIGH_OFF] = NFS_FILEID(inode) >> 32;
53 p[FILEID_LOW_OFF] = NFS_FILEID(inode);
54 p[FILE_I_TYPE_OFF] = inode->i_mode & S_IFMT;
55 p[len - 1] = 0; /* Padding */
56 nfs_copy_fh(clnt_fh, server_fh);
57 *max_len = len;
58 dprintk("%s: result fh fileid %llu mode %u size %d\n",
59 __func__, NFS_FILEID(inode), inode->i_mode, *max_len);
60 return *max_len;
61 }
62
63 static struct dentry *
64 nfs_fh_to_dentry(struct super_block *sb, struct fid *fid,
65 int fh_len, int fh_type)
66 {
67 struct nfs_fattr *fattr = NULL;
68 struct nfs_fh *server_fh = nfs_exp_embedfh(fid->raw);
69 size_t fh_size = offsetof(struct nfs_fh, data) + server_fh->size;
70 const struct nfs_rpc_ops *rpc_ops;
71 struct dentry *dentry;
72 struct inode *inode;
73 int len = EMBED_FH_OFF + XDR_QUADLEN(fh_size);
74 u32 *p = fid->raw;
75 int ret;
76
77 /* NULL translates to ESTALE */
78 if (fh_len < len || fh_type != len)
79 return NULL;
80
81 fattr = nfs_alloc_fattr_with_label(NFS_SB(sb));
82 if (fattr == NULL) {
83 dentry = ERR_PTR(-ENOMEM);
84 goto out;
85 }
86
87 fattr->fileid = ((u64)p[FILEID_HIGH_OFF] << 32) + p[FILEID_LOW_OFF];
88 fattr->mode = p[FILE_I_TYPE_OFF];
89 fattr->valid |= NFS_ATTR_FATTR_FILEID | NFS_ATTR_FATTR_TYPE;
90
91 dprintk("%s: fileid %llu mode %d\n", __func__, fattr->fileid, fattr->mode);
92
93 inode = nfs_ilookup(sb, fattr, server_fh);
94 if (inode)
95 goto out_found;
96
97 rpc_ops = NFS_SB(sb)->nfs_client->rpc_ops;
98 ret = rpc_ops->getattr(NFS_SB(sb), server_fh, fattr, NULL);
99 if (ret) {
100 dprintk("%s: getattr failed %d\n", __func__, ret);
101 trace_nfs_fh_to_dentry(sb, server_fh, fattr->fileid, ret);
102 dentry = ERR_PTR(ret);
103 goto out_free_fattr;
104 }
105
106 inode = nfs_fhget(sb, server_fh, fattr);
107
108 out_found:
109 dentry = d_obtain_alias(inode);
110 out_free_fattr:
111 nfs_free_fattr(fattr);
112 out:
113 return dentry;
114 }
115
116 static struct dentry *
117 nfs_get_parent(struct dentry *dentry)
118 {
119 int ret;
120 struct inode *inode = d_inode(dentry), *pinode;
121 struct super_block *sb = inode->i_sb;
122 struct nfs_server *server = NFS_SB(sb);
123 struct nfs_fattr *fattr = NULL;
124 struct dentry *parent;
125 struct nfs_rpc_ops const *ops = server->nfs_client->rpc_ops;
126 struct nfs_fh fh;
127
128 if (!ops->lookupp)
129 return ERR_PTR(-EACCES);
130
131 fattr = nfs_alloc_fattr_with_label(server);
132 if (fattr == NULL)
133 return ERR_PTR(-ENOMEM);
134
135 ret = ops->lookupp(inode, &fh, fattr);
136 if (ret) {
137 parent = ERR_PTR(ret);
138 goto out;
139 }
140
141 pinode = nfs_fhget(sb, &fh, fattr);
142 parent = d_obtain_alias(pinode);
143 out:
144 nfs_free_fattr(fattr);
145 return parent;
146 }
147
148 const struct export_operations nfs_export_ops = {
149 .encode_fh = nfs_encode_fh,
150 .fh_to_dentry = nfs_fh_to_dentry,
151 .get_parent = nfs_get_parent,
152 .flags = EXPORT_OP_NOWCC |
153 EXPORT_OP_NOSUBTREECHK |
154 EXPORT_OP_CLOSE_BEFORE_UNLINK |
155 EXPORT_OP_REMOTE_FS |
156 EXPORT_OP_NOATOMIC_ATTR |
157 EXPORT_OP_FLUSH_ON_CLOSE,
158 };
159
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