1
2
3
4
5
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
17enum {
18 FILEID_HIGH_OFF = 0,
19 FILEID_LOW_OFF,
20 FILE_I_TYPE_OFF,
21 EMBED_FH_OFF
22};
23
24
25static struct nfs_fh *nfs_exp_embedfh(__u32 *p)
26{
27 return (struct nfs_fh *)(p + EMBED_FH_OFF);
28}
29
30
31
32
33
34static int
35nfs_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 || IS_AUTOMOUNT(inode)) {
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;
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
63static struct dentry *
64nfs_fh_to_dentry(struct super_block *sb, struct fid *fid,
65 int fh_len, int fh_type)
66{
67 struct nfs4_label *label = NULL;
68 struct nfs_fattr *fattr = NULL;
69 struct nfs_fh *server_fh = nfs_exp_embedfh(fid->raw);
70 size_t fh_size = offsetof(struct nfs_fh, data) + server_fh->size;
71 const struct nfs_rpc_ops *rpc_ops;
72 struct dentry *dentry;
73 struct inode *inode;
74 int len = EMBED_FH_OFF + XDR_QUADLEN(fh_size);
75 u32 *p = fid->raw;
76 int ret;
77
78
79 if (fh_len < len || fh_type != len)
80 return NULL;
81
82 fattr = nfs_alloc_fattr();
83 if (fattr == NULL) {
84 dentry = ERR_PTR(-ENOMEM);
85 goto out;
86 }
87
88 fattr->fileid = ((u64)p[FILEID_HIGH_OFF] << 32) + p[FILEID_LOW_OFF];
89 fattr->mode = p[FILE_I_TYPE_OFF];
90 fattr->valid |= NFS_ATTR_FATTR_FILEID | NFS_ATTR_FATTR_TYPE;
91
92 dprintk("%s: fileid %llu mode %d\n", __func__, fattr->fileid, fattr->mode);
93
94 inode = nfs_ilookup(sb, fattr, server_fh);
95 if (inode)
96 goto out_found;
97
98 label = nfs4_label_alloc(NFS_SB(sb), GFP_KERNEL);
99 if (IS_ERR(label)) {
100 dentry = ERR_CAST(label);
101 goto out_free_fattr;
102 }
103
104 rpc_ops = NFS_SB(sb)->nfs_client->rpc_ops;
105 ret = rpc_ops->getattr(NFS_SB(sb), server_fh, fattr, label, NULL);
106 if (ret) {
107 dprintk("%s: getattr failed %d\n", __func__, ret);
108 trace_nfs_fh_to_dentry(sb, server_fh, fattr->fileid, ret);
109 dentry = ERR_PTR(ret);
110 goto out_free_label;
111 }
112
113 inode = nfs_fhget(sb, server_fh, fattr, label);
114
115out_found:
116 dentry = d_obtain_alias(inode);
117
118out_free_label:
119 nfs4_label_free(label);
120out_free_fattr:
121 nfs_free_fattr(fattr);
122out:
123 return dentry;
124}
125
126static struct dentry *
127nfs_get_parent(struct dentry *dentry)
128{
129 int ret;
130 struct inode *inode = d_inode(dentry), *pinode;
131 struct super_block *sb = inode->i_sb;
132 struct nfs_server *server = NFS_SB(sb);
133 struct nfs_fattr *fattr = NULL;
134 struct nfs4_label *label = NULL;
135 struct dentry *parent;
136 struct nfs_rpc_ops const *ops = server->nfs_client->rpc_ops;
137 struct nfs_fh fh;
138
139 if (!ops->lookupp)
140 return ERR_PTR(-EACCES);
141
142 fattr = nfs_alloc_fattr();
143 if (fattr == NULL) {
144 parent = ERR_PTR(-ENOMEM);
145 goto out;
146 }
147
148 label = nfs4_label_alloc(server, GFP_KERNEL);
149 if (IS_ERR(label)) {
150 parent = ERR_CAST(label);
151 goto out_free_fattr;
152 }
153
154 ret = ops->lookupp(inode, &fh, fattr, label);
155 if (ret) {
156 parent = ERR_PTR(ret);
157 goto out_free_label;
158 }
159
160 pinode = nfs_fhget(sb, &fh, fattr, label);
161 parent = d_obtain_alias(pinode);
162out_free_label:
163 nfs4_label_free(label);
164out_free_fattr:
165 nfs_free_fattr(fattr);
166out:
167 return parent;
168}
169
170static u64 nfs_fetch_iversion(struct inode *inode)
171{
172 nfs_revalidate_inode(inode, NFS_INO_INVALID_CHANGE);
173 return inode_peek_iversion_raw(inode);
174}
175
176const struct export_operations nfs_export_ops = {
177 .encode_fh = nfs_encode_fh,
178 .fh_to_dentry = nfs_fh_to_dentry,
179 .get_parent = nfs_get_parent,
180 .fetch_iversion = nfs_fetch_iversion,
181 .flags = EXPORT_OP_NOWCC|EXPORT_OP_NOSUBTREECHK|
182 EXPORT_OP_CLOSE_BEFORE_UNLINK|EXPORT_OP_REMOTE_FS|
183 EXPORT_OP_NOATOMIC_ATTR|EXPORT_OP_SYNC_LOCKS,
184};
185
