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_fh(const struct knfsd_fh *fh,
135 struct svc_export *exp);
136 extern enum fsid_source fsid_source(const struct svc_fh *fhp);
137
138
139 /*
140 * This might look a little large to "inline" but in all calls except
141 * one, 'vers' is constant so moste of the function disappears.
142 *
143 * In some cases the values are considered to be host endian and in
144 * others, net endian. fsidv is always considered to be u32 as the
145 * callers don't know which it will be. So we must use __force to keep
146 * sparse from complaining. Since these values are opaque to the
147 * client, that shouldn't be a problem.
148 */
mk_fsid(int vers,u32 * fsidv,dev_t dev,ino_t ino,u32 fsid,unsigned char * uuid)149 static inline void mk_fsid(int vers, u32 *fsidv, dev_t dev, ino_t ino,
150 u32 fsid, unsigned char *uuid)
151 {
152 u32 *up;
153 switch(vers) {
154 case FSID_DEV:
155 fsidv[0] = (__force __u32)htonl((MAJOR(dev)<<16) |
156 MINOR(dev));
157 fsidv[1] = ino_t_to_u32(ino);
158 break;
159 case FSID_NUM:
160 fsidv[0] = fsid;
161 break;
162 case FSID_MAJOR_MINOR:
163 fsidv[0] = (__force __u32)htonl(MAJOR(dev));
164 fsidv[1] = (__force __u32)htonl(MINOR(dev));
165 fsidv[2] = ino_t_to_u32(ino);
166 break;
167
168 case FSID_ENCODE_DEV:
169 fsidv[0] = new_encode_dev(dev);
170 fsidv[1] = ino_t_to_u32(ino);
171 break;
172
173 case FSID_UUID4_INUM:
174 /* 4 byte fsid and inode number */
175 up = (u32*)uuid;
176 fsidv[0] = ino_t_to_u32(ino);
177 fsidv[1] = up[0] ^ up[1] ^ up[2] ^ up[3];
178 break;
179
180 case FSID_UUID8:
181 /* 8 byte fsid */
182 up = (u32*)uuid;
183 fsidv[0] = up[0] ^ up[2];
184 fsidv[1] = up[1] ^ up[3];
185 break;
186
187 case FSID_UUID16:
188 /* 16 byte fsid - NFSv3+ only */
189 memcpy(fsidv, uuid, 16);
190 break;
191
192 case FSID_UUID16_INUM:
193 /* 8 byte inode and 16 byte fsid */
194 *(u64*)fsidv = (u64)ino;
195 memcpy(fsidv+2, uuid, 16);
196 break;
197 default: BUG();
198 }
199 }
200
key_len(int type)201 static inline int key_len(int type)
202 {
203 switch(type) {
204 case FSID_DEV: return 8;
205 case FSID_NUM: return 4;
206 case FSID_MAJOR_MINOR: return 12;
207 case FSID_ENCODE_DEV: return 8;
208 case FSID_UUID4_INUM: return 8;
209 case FSID_UUID8: return 8;
210 case FSID_UUID16: return 16;
211 case FSID_UUID16_INUM: return 24;
212 default: return 0;
213 }
214 }
215
216 /*
217 * Shorthand for dprintk()'s
218 */
219 extern char * SVCFH_fmt(struct svc_fh *fhp);
220
221 /*
222 * Function prototypes
223 */
224 __be32 fh_verify(struct svc_rqst *, struct svc_fh *, umode_t, int);
225 __be32 fh_verify_local(struct net *, struct svc_cred *, struct auth_domain *,
226 struct svc_fh *, umode_t, int);
227 __be32 fh_getattr(const struct svc_fh *fhp, struct kstat *stat);
228 __be32 fh_compose(struct svc_fh *, struct svc_export *, struct dentry *, struct svc_fh *);
229 __be32 fh_update(struct svc_fh *);
230 void fh_put(struct svc_fh *);
231 bool fh_append_mac(struct knfsd_fh *fh, int fh_maxsize, struct net *net);
232
233 static __inline__ struct svc_fh *
fh_copy(struct svc_fh * dst,const struct svc_fh * src)234 fh_copy(struct svc_fh *dst, const struct svc_fh *src)
235 {
236 WARN_ON(src->fh_dentry);
237
238 *dst = *src;
239 return dst;
240 }
241
242 static inline void
fh_copy_shallow(struct knfsd_fh * dst,const struct knfsd_fh * src)243 fh_copy_shallow(struct knfsd_fh *dst, const struct knfsd_fh *src)
244 {
245 dst->fh_size = src->fh_size;
246 memcpy(&dst->fh_raw, &src->fh_raw, src->fh_size);
247 }
248
249 static __inline__ struct svc_fh *
fh_init(struct svc_fh * fhp,int maxsize)250 fh_init(struct svc_fh *fhp, int maxsize)
251 {
252 memset(fhp, 0, sizeof(*fhp));
253 fhp->fh_maxsize = maxsize;
254 return fhp;
255 }
256
fh_match(const struct knfsd_fh * fh1,const struct knfsd_fh * fh2)257 static inline bool fh_match(const struct knfsd_fh *fh1,
258 const struct knfsd_fh *fh2)
259 {
260 if (fh1->fh_size != fh2->fh_size)
261 return false;
262 if (memcmp(fh1->fh_raw, fh2->fh_raw, fh1->fh_size) != 0)
263 return false;
264 return true;
265 }
266
fh_fsid_match(const struct knfsd_fh * fh1,const struct knfsd_fh * fh2)267 static inline bool fh_fsid_match(const struct knfsd_fh *fh1,
268 const struct knfsd_fh *fh2)
269 {
270 u32 *fsid1 = fh_fsid(fh1);
271 u32 *fsid2 = fh_fsid(fh2);
272
273 if (fh1->fh_fsid_type != fh2->fh_fsid_type)
274 return false;
275 if (memcmp(fsid1, fsid2, key_len(fh1->fh_fsid_type)) != 0)
276 return false;
277 return true;
278 }
279
280 /**
281 * fh_want_write - Get write access to an export
282 * @fhp: File handle of file to be written
283 *
284 * Caller must invoke fh_drop_write() when its write operation
285 * is complete.
286 *
287 * Returns 0 if the file handle's export can be written to. Otherwise
288 * the export is not prepared for updates, and the returned negative
289 * errno value reflects the reason for the failure.
290 */
fh_want_write(struct svc_fh * fhp)291 static inline int fh_want_write(struct svc_fh *fhp)
292 {
293 int ret;
294
295 if (fhp->fh_want_write)
296 return 0;
297 ret = mnt_want_write(fhp->fh_export->ex_path.mnt);
298 if (!ret)
299 fhp->fh_want_write = true;
300 return ret;
301 }
302
303 /**
304 * fh_drop_write - Release write access on an export
305 * @fhp: File handle of file on which fh_want_write() was previously called
306 */
fh_drop_write(struct svc_fh * fhp)307 static inline void fh_drop_write(struct svc_fh *fhp)
308 {
309 if (fhp->fh_want_write) {
310 fhp->fh_want_write = false;
311 mnt_drop_write(fhp->fh_export->ex_path.mnt);
312 }
313 }
314
315 /**
316 * knfsd_fh_hash - calculate the crc32 hash for the filehandle
317 * @fh - pointer to filehandle
318 *
319 * returns a crc32 hash for the filehandle that is compatible with
320 * the one displayed by "wireshark".
321 */
knfsd_fh_hash(const struct knfsd_fh * fh)322 static inline u32 knfsd_fh_hash(const struct knfsd_fh *fh)
323 {
324 return ~crc32_le(0xFFFFFFFF, fh->fh_raw, fh->fh_size);
325 }
326
327 /**
328 * fh_clear_pre_post_attrs - Reset pre/post attributes
329 * @fhp: file handle to be updated
330 *
331 */
fh_clear_pre_post_attrs(struct svc_fh * fhp)332 static inline void fh_clear_pre_post_attrs(struct svc_fh *fhp)
333 {
334 fhp->fh_post_saved = false;
335 fhp->fh_pre_saved = false;
336 }
337
338 u64 nfsd4_change_attribute(const struct kstat *stat);
339 __be32 __must_check fh_fill_pre_attrs(struct svc_fh *fhp);
340 __be32 fh_fill_post_attrs(struct svc_fh *fhp);
341 __be32 __must_check fh_fill_both_attrs(struct svc_fh *fhp);
342 #endif /* _LINUX_NFSD_NFSFH_H */
343