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 /*
18 * The file handle starts with a sequence of four-byte words.
19 * The first word contains a version number (1) and three descriptor bytes
20 * that tell how the remaining 3 variable length fields should be handled.
21 * These three bytes are auth_type, fsid_type and fileid_type.
22 *
23 * All four-byte values are in host-byte-order.
24 *
25 * The auth_type field is deprecated and must be set to 0.
26 *
27 * The fsid_type identifies how the filesystem (or export point) is
28 * encoded.
29 * Current values:
30 * 0 - 4 byte device id (ms-2-bytes major, ls-2-bytes minor), 4byte inode number
31 * NOTE: we cannot use the kdev_t device id value, because kdev_t.h
32 * says we mustn't. We must break it up and reassemble.
33 * 1 - 4 byte user specified identifier
34 * 2 - 4 byte major, 4 byte minor, 4 byte inode number - DEPRECATED
35 * 3 - 4 byte device id, encoded for user-space, 4 byte inode number
36 * 4 - 4 byte inode number and 4 byte uuid
37 * 5 - 8 byte uuid
38 * 6 - 16 byte uuid
39 * 7 - 8 byte inode number and 16 byte uuid
40 *
41 * The fileid_type identifies how the file within the filesystem is encoded.
42 * The values for this field are filesystem specific, exccept that
43 * filesystems must not use the values '0' or '0xff'. 'See enum fid_type'
44 * in include/linux/exportfs.h for currently registered values.
45 */
46
47 struct knfsd_fh {
48 unsigned int fh_size; /*
49 * Points to the current size while
50 * building a new file handle.
51 */
52 union {
53 char fh_raw[NFS4_FHSIZE];
54 struct {
55 u8 fh_version; /* == 1 */
56 u8 fh_auth_type; /* deprecated */
57 u8 fh_fsid_type;
58 u8 fh_fileid_type;
59 u32 fh_fsid[]; /* flexible-array member */
60 };
61 };
62 };
63
ino_t_to_u32(ino_t ino)64 static inline __u32 ino_t_to_u32(ino_t ino)
65 {
66 return (__u32) ino;
67 }
68
u32_to_ino_t(__u32 uino)69 static inline ino_t u32_to_ino_t(__u32 uino)
70 {
71 return (ino_t) uino;
72 }
73
74 /*
75 * This is the internal representation of an NFS handle used in knfsd.
76 * pre_mtime/post_version will be used to support wcc_attr's in NFSv3.
77 */
78 typedef struct svc_fh {
79 struct knfsd_fh fh_handle; /* FH data */
80 int fh_maxsize; /* max size for fh_handle */
81 struct dentry * fh_dentry; /* validated dentry */
82 struct svc_export * fh_export; /* export pointer */
83
84 bool fh_locked; /* inode locked by us */
85 bool fh_want_write; /* remount protection taken */
86 bool fh_no_wcc; /* no wcc data needed */
87 bool fh_no_atomic_attr;
88 /*
89 * wcc data is not atomic with
90 * operation
91 */
92 int fh_flags; /* FH flags */
93 #ifdef CONFIG_NFSD_V3
94 bool fh_post_saved; /* post-op attrs saved */
95 bool fh_pre_saved; /* pre-op attrs saved */
96
97 /* Pre-op attributes saved during fh_lock */
98 __u64 fh_pre_size; /* size before operation */
99 struct timespec64 fh_pre_mtime; /* mtime before oper */
100 struct timespec64 fh_pre_ctime; /* ctime before oper */
101 /*
102 * pre-op nfsv4 change attr: note must check IS_I_VERSION(inode)
103 * to find out if it is valid.
104 */
105 u64 fh_pre_change;
106
107 /* Post-op attributes saved in fh_unlock */
108 struct kstat fh_post_attr; /* full attrs after operation */
109 u64 fh_post_change; /* nfsv4 change; see above */
110 #endif /* CONFIG_NFSD_V3 */
111 } svc_fh;
112 #define NFSD4_FH_FOREIGN (1<<0)
113 #define SET_FH_FLAG(c, f) ((c)->fh_flags |= (f))
114 #define HAS_FH_FLAG(c, f) ((c)->fh_flags & (f))
115
116 enum nfsd_fsid {
117 FSID_DEV = 0,
118 FSID_NUM,
119 FSID_MAJOR_MINOR,
120 FSID_ENCODE_DEV,
121 FSID_UUID4_INUM,
122 FSID_UUID8,
123 FSID_UUID16,
124 FSID_UUID16_INUM,
125 };
126
127 enum fsid_source {
128 FSIDSOURCE_DEV,
129 FSIDSOURCE_FSID,
130 FSIDSOURCE_UUID,
131 };
132 extern enum fsid_source fsid_source(const struct svc_fh *fhp);
133
134
135 /*
136 * This might look a little large to "inline" but in all calls except
137 * one, 'vers' is constant so moste of the function disappears.
138 *
139 * In some cases the values are considered to be host endian and in
140 * others, net endian. fsidv is always considered to be u32 as the
141 * callers don't know which it will be. So we must use __force to keep
142 * sparse from complaining. Since these values are opaque to the
143 * client, that shouldn't be a problem.
144 */
mk_fsid(int vers,u32 * fsidv,dev_t dev,ino_t ino,u32 fsid,unsigned char * uuid)145 static inline void mk_fsid(int vers, u32 *fsidv, dev_t dev, ino_t ino,
146 u32 fsid, unsigned char *uuid)
147 {
148 u32 *up;
149 switch(vers) {
150 case FSID_DEV:
151 fsidv[0] = (__force __u32)htonl((MAJOR(dev)<<16) |
152 MINOR(dev));
153 fsidv[1] = ino_t_to_u32(ino);
154 break;
155 case FSID_NUM:
156 fsidv[0] = fsid;
157 break;
158 case FSID_MAJOR_MINOR:
159 fsidv[0] = (__force __u32)htonl(MAJOR(dev));
160 fsidv[1] = (__force __u32)htonl(MINOR(dev));
161 fsidv[2] = ino_t_to_u32(ino);
162 break;
163
164 case FSID_ENCODE_DEV:
165 fsidv[0] = new_encode_dev(dev);
166 fsidv[1] = ino_t_to_u32(ino);
167 break;
168
169 case FSID_UUID4_INUM:
170 /* 4 byte fsid and inode number */
171 up = (u32*)uuid;
172 fsidv[0] = ino_t_to_u32(ino);
173 fsidv[1] = up[0] ^ up[1] ^ up[2] ^ up[3];
174 break;
175
176 case FSID_UUID8:
177 /* 8 byte fsid */
178 up = (u32*)uuid;
179 fsidv[0] = up[0] ^ up[2];
180 fsidv[1] = up[1] ^ up[3];
181 break;
182
183 case FSID_UUID16:
184 /* 16 byte fsid - NFSv3+ only */
185 memcpy(fsidv, uuid, 16);
186 break;
187
188 case FSID_UUID16_INUM:
189 /* 8 byte inode and 16 byte fsid */
190 *(u64*)fsidv = (u64)ino;
191 memcpy(fsidv+2, uuid, 16);
192 break;
193 default: BUG();
194 }
195 }
196
key_len(int type)197 static inline int key_len(int type)
198 {
199 switch(type) {
200 case FSID_DEV: return 8;
201 case FSID_NUM: return 4;
202 case FSID_MAJOR_MINOR: return 12;
203 case FSID_ENCODE_DEV: return 8;
204 case FSID_UUID4_INUM: return 8;
205 case FSID_UUID8: return 8;
206 case FSID_UUID16: return 16;
207 case FSID_UUID16_INUM: return 24;
208 default: return 0;
209 }
210 }
211
212 /*
213 * Shorthand for dprintk()'s
214 */
215 extern char * SVCFH_fmt(struct svc_fh *fhp);
216
217 /*
218 * Function prototypes
219 */
220 __be32 fh_verify(struct svc_rqst *, struct svc_fh *, umode_t, int);
221 __be32 fh_compose(struct svc_fh *, struct svc_export *, struct dentry *, struct svc_fh *);
222 __be32 fh_update(struct svc_fh *);
223 void fh_put(struct svc_fh *);
224
225 static __inline__ struct svc_fh *
fh_copy(struct svc_fh * dst,struct svc_fh * src)226 fh_copy(struct svc_fh *dst, struct svc_fh *src)
227 {
228 WARN_ON(src->fh_dentry || src->fh_locked);
229
230 *dst = *src;
231 return dst;
232 }
233
234 static inline void
fh_copy_shallow(struct knfsd_fh * dst,struct knfsd_fh * src)235 fh_copy_shallow(struct knfsd_fh *dst, struct knfsd_fh *src)
236 {
237 dst->fh_size = src->fh_size;
238 memcpy(&dst->fh_raw, &src->fh_raw, src->fh_size);
239 }
240
241 static __inline__ struct svc_fh *
fh_init(struct svc_fh * fhp,int maxsize)242 fh_init(struct svc_fh *fhp, int maxsize)
243 {
244 memset(fhp, 0, sizeof(*fhp));
245 fhp->fh_maxsize = maxsize;
246 return fhp;
247 }
248
fh_match(struct knfsd_fh * fh1,struct knfsd_fh * fh2)249 static inline bool fh_match(struct knfsd_fh *fh1, struct knfsd_fh *fh2)
250 {
251 if (fh1->fh_size != fh2->fh_size)
252 return false;
253 if (memcmp(fh1->fh_raw, fh2->fh_raw, fh1->fh_size) != 0)
254 return false;
255 return true;
256 }
257
fh_fsid_match(struct knfsd_fh * fh1,struct knfsd_fh * fh2)258 static inline bool fh_fsid_match(struct knfsd_fh *fh1, struct knfsd_fh *fh2)
259 {
260 if (fh1->fh_fsid_type != fh2->fh_fsid_type)
261 return false;
262 if (memcmp(fh1->fh_fsid, fh2->fh_fsid, key_len(fh1->fh_fsid_type)) != 0)
263 return false;
264 return true;
265 }
266
267 #ifdef CONFIG_CRC32
268 /**
269 * knfsd_fh_hash - calculate the crc32 hash for the filehandle
270 * @fh - pointer to filehandle
271 *
272 * returns a crc32 hash for the filehandle that is compatible with
273 * the one displayed by "wireshark".
274 */
knfsd_fh_hash(const struct knfsd_fh * fh)275 static inline u32 knfsd_fh_hash(const struct knfsd_fh *fh)
276 {
277 return ~crc32_le(0xFFFFFFFF, fh->fh_raw, fh->fh_size);
278 }
279 #else
knfsd_fh_hash(const struct knfsd_fh * fh)280 static inline u32 knfsd_fh_hash(const struct knfsd_fh *fh)
281 {
282 return 0;
283 }
284 #endif
285
286 #ifdef CONFIG_NFSD_V3
287 /*
288 * The wcc data stored in current_fh should be cleared
289 * between compound ops.
290 */
291 static inline void
fh_clear_wcc(struct svc_fh * fhp)292 fh_clear_wcc(struct svc_fh *fhp)
293 {
294 fhp->fh_post_saved = false;
295 fhp->fh_pre_saved = false;
296 }
297
298 /*
299 * We could use i_version alone as the change attribute. However,
300 * i_version can go backwards after a reboot. On its own that doesn't
301 * necessarily cause a problem, but if i_version goes backwards and then
302 * is incremented again it could reuse a value that was previously used
303 * before boot, and a client who queried the two values might
304 * incorrectly assume nothing changed.
305 *
306 * By using both ctime and the i_version counter we guarantee that as
307 * long as time doesn't go backwards we never reuse an old value.
308 */
nfsd4_change_attribute(struct kstat * stat,struct inode * inode)309 static inline u64 nfsd4_change_attribute(struct kstat *stat,
310 struct inode *inode)
311 {
312 if (inode->i_sb->s_export_op->fetch_iversion)
313 return inode->i_sb->s_export_op->fetch_iversion(inode);
314 else if (IS_I_VERSION(inode)) {
315 u64 chattr;
316
317 chattr = stat->ctime.tv_sec;
318 chattr <<= 30;
319 chattr += stat->ctime.tv_nsec;
320 chattr += inode_query_iversion(inode);
321 return chattr;
322 } else
323 return time_to_chattr(&stat->ctime);
324 }
325
326 extern void fill_pre_wcc(struct svc_fh *fhp);
327 extern void fill_post_wcc(struct svc_fh *fhp);
328 #else
329 #define fh_clear_wcc(ignored)
330 #define fill_pre_wcc(ignored)
331 #define fill_post_wcc(notused)
332 #endif /* CONFIG_NFSD_V3 */
333
334
335 /*
336 * Lock a file handle/inode
337 * NOTE: both fh_lock and fh_unlock are done "by hand" in
338 * vfs.c:nfsd_rename as it needs to grab 2 i_mutex's at once
339 * so, any changes here should be reflected there.
340 */
341
342 static inline void
fh_lock_nested(struct svc_fh * fhp,unsigned int subclass)343 fh_lock_nested(struct svc_fh *fhp, unsigned int subclass)
344 {
345 struct dentry *dentry = fhp->fh_dentry;
346 struct inode *inode;
347
348 BUG_ON(!dentry);
349
350 if (fhp->fh_locked) {
351 printk(KERN_WARNING "fh_lock: %pd2 already locked!\n",
352 dentry);
353 return;
354 }
355
356 inode = d_inode(dentry);
357 inode_lock_nested(inode, subclass);
358 fill_pre_wcc(fhp);
359 fhp->fh_locked = true;
360 }
361
362 static inline void
fh_lock(struct svc_fh * fhp)363 fh_lock(struct svc_fh *fhp)
364 {
365 fh_lock_nested(fhp, I_MUTEX_NORMAL);
366 }
367
368 /*
369 * Unlock a file handle/inode
370 */
371 static inline void
fh_unlock(struct svc_fh * fhp)372 fh_unlock(struct svc_fh *fhp)
373 {
374 if (fhp->fh_locked) {
375 fill_post_wcc(fhp);
376 inode_unlock(d_inode(fhp->fh_dentry));
377 fhp->fh_locked = false;
378 }
379 }
380
381 #endif /* _LINUX_NFSD_NFSFH_H */
382