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(target: clnt_fh, source: 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(p: 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(server: NFS_SB(s: sb)); |
82 | if (fattr == NULL) { |
83 | dentry = ERR_PTR(error: -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(s: sb)->nfs_client->rpc_ops; |
98 | ret = rpc_ops->getattr(NFS_SB(s: sb), server_fh, fattr, NULL); |
99 | if (ret) { |
100 | dprintk("%s: getattr failed %d\n" , __func__, ret); |
101 | trace_nfs_fh_to_dentry(sb, fh: server_fh, fileid: fattr->fileid, error: ret); |
102 | dentry = ERR_PTR(error: 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(s: 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(error: -EACCES); |
130 | |
131 | fattr = nfs_alloc_fattr_with_label(server); |
132 | if (fattr == NULL) |
133 | return ERR_PTR(error: -ENOMEM); |
134 | |
135 | ret = ops->lookupp(inode, &fh, fattr); |
136 | if (ret) { |
137 | parent = ERR_PTR(error: 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 | |