1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3 * Copyright (C) 1995, 1996, 1997 Olaf Kirch <okir@monad.swb.de>
4 *
5 * This file describes the layout of the file handles as passed
6 * over the wire.
7 */
8 #ifndef _LINUX_NFSD_NFSFH_H
9 #define _LINUX_NFSD_NFSFH_H
10
11 #include <linux/crc32.h>
12 #include <linux/sunrpc/svc.h>
13 #include <linux/iversion.h>
14 #include <linux/exportfs.h>
15 #include <linux/nfs4.h>
16
17 #include "export.h"
18
19 /*
20 * The file handle starts with a sequence of four-byte words.
21 * The first word contains a version number (1) and three descriptor bytes
22 * that tell how the remaining 3 variable length fields should be handled.
23 * These three bytes are auth_type, fsid_type and fileid_type.
24 *
25 * All four-byte values are in host-byte-order.
26 *
27 * The auth_type field is deprecated and must be set to 0.
28 *
29 * The fsid_type identifies how the filesystem (or export point) is
30 * encoded.
31 * Current values:
32 * 0 - 4 byte device id (ms-2-bytes major, ls-2-bytes minor), 4byte inode number
33 * NOTE: we cannot use the kdev_t device id value, because kdev_t.h
34 * says we mustn't. We must break it up and reassemble.
35 * 1 - 4 byte user specified identifier
36 * 2 - 4 byte major, 4 byte minor, 4 byte inode number - DEPRECATED
37 * 3 - 4 byte device id, encoded for user-space, 4 byte inode number
38 * 4 - 4 byte inode number and 4 byte uuid
39 * 5 - 8 byte uuid
40 * 6 - 16 byte uuid
41 * 7 - 8 byte inode number and 16 byte uuid
42 *
43 * The fileid_type identifies how the file within the filesystem is encoded.
44 * The values for this field are filesystem specific, exccept that
45 * filesystems must not use the values '0' or '0xff'. 'See enum fid_type'
46 * in include/linux/exportfs.h for currently registered values.
47 */
48
49 struct knfsd_fh {
50 unsigned int fh_size; /*
51 * Points to the current size while
52 * building a new file handle.
53 */
54 u8 fh_raw[NFS4_FHSIZE];
55 };
56
57 #define fh_version fh_raw[0]
58 #define fh_auth_type fh_raw[1]
59 #define fh_fsid_type fh_raw[2]
60 #define fh_fileid_type fh_raw[3]
61
fh_fsid(const struct knfsd_fh * fh)62 static inline u32 *fh_fsid(const struct knfsd_fh *fh)
63 {
64 return (u32 *)&fh->fh_raw[4];
65 }
66
ino_t_to_u32(ino_t ino)67 static inline __u32 ino_t_to_u32(ino_t ino)
68 {
69 return (__u32) ino;
70 }
71
u32_to_ino_t(__u32 uino)72 static inline ino_t u32_to_ino_t(__u32 uino)
73 {
74 return (ino_t) uino;
75 }
76
77 /*
78 * This is the internal representation of an NFS handle used in knfsd.
79 * pre_mtime/post_version will be used to support wcc_attr's in NFSv3.
80 */
81 typedef struct svc_fh {
82 struct knfsd_fh fh_handle; /* FH data */
83 int fh_maxsize; /* max size for fh_handle */
84 struct dentry * fh_dentry; /* validated dentry */
85 struct svc_export * fh_export; /* export pointer */
86
87 bool fh_want_write; /* remount protection taken */
88 bool fh_no_wcc; /* no wcc data needed */
89 bool fh_no_atomic_attr;
90 /*
91 * wcc data is not atomic with
92 * operation
93 */
94 bool fh_use_wgather; /* NFSv2 wgather option */
95 bool fh_64bit_cookies;/* readdir cookie size */
96 int fh_flags; /* FH flags */
97 bool fh_post_saved; /* post-op attrs saved */
98 bool fh_pre_saved; /* pre-op attrs saved */
99
100 /* Pre-op attributes saved when inode is locked */
101 __u64 fh_pre_size; /* size before operation */
102 struct timespec64 fh_pre_mtime; /* mtime before oper */
103 struct timespec64 fh_pre_ctime; /* ctime before oper */
104 /*
105 * pre-op nfsv4 change attr: note must check IS_I_VERSION(inode)
106 * to find out if it is valid.
107 */
108 u64 fh_pre_change;
109
110 /* Post-op attributes saved in fh_fill_post_attrs() */
111 struct kstat fh_post_attr; /* full attrs after operation */
112 u64 fh_post_change; /* nfsv4 change; see above */
113 } svc_fh;
114 #define NFSD4_FH_FOREIGN (1<<0)
115 #define SET_FH_FLAG(c, f) ((c)->fh_flags |= (f))
116 #define HAS_FH_FLAG(c, f) ((c)->fh_flags & (f))
117
118 enum nfsd_fsid {
119 FSID_DEV = 0,
120 FSID_NUM,
121 FSID_MAJOR_MINOR,
122 FSID_ENCODE_DEV,
123 FSID_UUID4_INUM,
124 FSID_UUID8,
125 FSID_UUID16,
126 FSID_UUID16_INUM,
127 };
128
129 enum fsid_source {
130 FSIDSOURCE_DEV,
131 FSIDSOURCE_FSID,
132 FSIDSOURCE_UUID,
133 };
134 extern enum fsid_source fsid_source(const struct svc_fh *fhp);
135
136
137 /*
138 * This might look a little large to "inline" but in all calls except
139 * one, 'vers' is constant so moste of the function disappears.
140 *
141 * In some cases the values are considered to be host endian and in
142 * others, net endian. fsidv is always considered to be u32 as the
143 * callers don't know which it will be. So we must use __force to keep
144 * sparse from complaining. Since these values are opaque to the
145 * client, that shouldn't be a problem.
146 */
mk_fsid(int vers,u32 * fsidv,dev_t dev,ino_t ino,u32 fsid,unsigned char * uuid)147 static inline void mk_fsid(int vers, u32 *fsidv, dev_t dev, ino_t ino,
148 u32 fsid, unsigned char *uuid)
149 {
150 u32 *up;
151 switch(vers) {
152 case FSID_DEV:
153 fsidv[0] = (__force __u32)htonl((MAJOR(dev)<<16) |
154 MINOR(dev));
155 fsidv[1] = ino_t_to_u32(ino);
156 break;
157 case FSID_NUM:
158 fsidv[0] = fsid;
159 break;
160 case FSID_MAJOR_MINOR:
161 fsidv[0] = (__force __u32)htonl(MAJOR(dev));
162 fsidv[1] = (__force __u32)htonl(MINOR(dev));
163 fsidv[2] = ino_t_to_u32(ino);
164 break;
165
166 case FSID_ENCODE_DEV:
167 fsidv[0] = new_encode_dev(dev);
168 fsidv[1] = ino_t_to_u32(ino);
169 break;
170
171 case FSID_UUID4_INUM:
172 /* 4 byte fsid and inode number */
173 up = (u32*)uuid;
174 fsidv[0] = ino_t_to_u32(ino);
175 fsidv[1] = up[0] ^ up[1] ^ up[2] ^ up[3];
176 break;
177
178 case FSID_UUID8:
179 /* 8 byte fsid */
180 up = (u32*)uuid;
181 fsidv[0] = up[0] ^ up[2];
182 fsidv[1] = up[1] ^ up[3];
183 break;
184
185 case FSID_UUID16:
186 /* 16 byte fsid - NFSv3+ only */
187 memcpy(fsidv, uuid, 16);
188 break;
189
190 case FSID_UUID16_INUM:
191 /* 8 byte inode and 16 byte fsid */
192 *(u64*)fsidv = (u64)ino;
193 memcpy(fsidv+2, uuid, 16);
194 break;
195 default: BUG();
196 }
197 }
198
key_len(int type)199 static inline int key_len(int type)
200 {
201 switch(type) {
202 case FSID_DEV: return 8;
203 case FSID_NUM: return 4;
204 case FSID_MAJOR_MINOR: return 12;
205 case FSID_ENCODE_DEV: return 8;
206 case FSID_UUID4_INUM: return 8;
207 case FSID_UUID8: return 8;
208 case FSID_UUID16: return 16;
209 case FSID_UUID16_INUM: return 24;
210 default: return 0;
211 }
212 }
213
214 /*
215 * Shorthand for dprintk()'s
216 */
217 extern char * SVCFH_fmt(struct svc_fh *fhp);
218
219 /*
220 * Function prototypes
221 */
222 __be32 fh_verify(struct svc_rqst *, struct svc_fh *, umode_t, int);
223 __be32 fh_verify_local(struct net *, struct svc_cred *, struct auth_domain *,
224 struct svc_fh *, umode_t, int);
225 __be32 fh_getattr(const struct svc_fh *fhp, struct kstat *stat);
226 __be32 fh_compose(struct svc_fh *, struct svc_export *, struct dentry *, struct svc_fh *);
227 __be32 fh_update(struct svc_fh *);
228 void fh_put(struct svc_fh *);
229
230 static __inline__ struct svc_fh *
fh_copy(struct svc_fh * dst,const struct svc_fh * src)231 fh_copy(struct svc_fh *dst, const struct svc_fh *src)
232 {
233 WARN_ON(src->fh_dentry);
234
235 *dst = *src;
236 return dst;
237 }
238
239 static inline void
fh_copy_shallow(struct knfsd_fh * dst,const struct knfsd_fh * src)240 fh_copy_shallow(struct knfsd_fh *dst, const struct knfsd_fh *src)
241 {
242 dst->fh_size = src->fh_size;
243 memcpy(&dst->fh_raw, &src->fh_raw, src->fh_size);
244 }
245
246 static __inline__ struct svc_fh *
fh_init(struct svc_fh * fhp,int maxsize)247 fh_init(struct svc_fh *fhp, int maxsize)
248 {
249 memset(fhp, 0, sizeof(*fhp));
250 fhp->fh_maxsize = maxsize;
251 return fhp;
252 }
253
fh_match(const struct knfsd_fh * fh1,const struct knfsd_fh * fh2)254 static inline bool fh_match(const struct knfsd_fh *fh1,
255 const struct knfsd_fh *fh2)
256 {
257 if (fh1->fh_size != fh2->fh_size)
258 return false;
259 if (memcmp(fh1->fh_raw, fh2->fh_raw, fh1->fh_size) != 0)
260 return false;
261 return true;
262 }
263
fh_fsid_match(const struct knfsd_fh * fh1,const struct knfsd_fh * fh2)264 static inline bool fh_fsid_match(const struct knfsd_fh *fh1,
265 const struct knfsd_fh *fh2)
266 {
267 u32 *fsid1 = fh_fsid(fh1);
268 u32 *fsid2 = fh_fsid(fh2);
269
270 if (fh1->fh_fsid_type != fh2->fh_fsid_type)
271 return false;
272 if (memcmp(fsid1, fsid2, key_len(fh1->fh_fsid_type)) != 0)
273 return false;
274 return true;
275 }
276
277 /**
278 * fh_want_write - Get write access to an export
279 * @fhp: File handle of file to be written
280 *
281 * Caller must invoke fh_drop_write() when its write operation
282 * is complete.
283 *
284 * Returns 0 if the file handle's export can be written to. Otherwise
285 * the export is not prepared for updates, and the returned negative
286 * errno value reflects the reason for the failure.
287 */
fh_want_write(struct svc_fh * fhp)288 static inline int fh_want_write(struct svc_fh *fhp)
289 {
290 int ret;
291
292 if (fhp->fh_want_write)
293 return 0;
294 ret = mnt_want_write(fhp->fh_export->ex_path.mnt);
295 if (!ret)
296 fhp->fh_want_write = true;
297 return ret;
298 }
299
300 /**
301 * fh_drop_write - Release write access on an export
302 * @fhp: File handle of file on which fh_want_write() was previously called
303 */
fh_drop_write(struct svc_fh * fhp)304 static inline void fh_drop_write(struct svc_fh *fhp)
305 {
306 if (fhp->fh_want_write) {
307 fhp->fh_want_write = false;
308 mnt_drop_write(fhp->fh_export->ex_path.mnt);
309 }
310 }
311
312 /**
313 * knfsd_fh_hash - calculate the crc32 hash for the filehandle
314 * @fh - pointer to filehandle
315 *
316 * returns a crc32 hash for the filehandle that is compatible with
317 * the one displayed by "wireshark".
318 */
knfsd_fh_hash(const struct knfsd_fh * fh)319 static inline u32 knfsd_fh_hash(const struct knfsd_fh *fh)
320 {
321 return ~crc32_le(0xFFFFFFFF, fh->fh_raw, fh->fh_size);
322 }
323
324 /**
325 * fh_clear_pre_post_attrs - Reset pre/post attributes
326 * @fhp: file handle to be updated
327 *
328 */
fh_clear_pre_post_attrs(struct svc_fh * fhp)329 static inline void fh_clear_pre_post_attrs(struct svc_fh *fhp)
330 {
331 fhp->fh_post_saved = false;
332 fhp->fh_pre_saved = false;
333 }
334
335 u64 nfsd4_change_attribute(const struct kstat *stat);
336 __be32 __must_check fh_fill_pre_attrs(struct svc_fh *fhp);
337 __be32 fh_fill_post_attrs(struct svc_fh *fhp);
338 __be32 __must_check fh_fill_both_attrs(struct svc_fh *fhp);
339 #endif /* _LINUX_NFSD_NFSFH_H */
340