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_want_write; /* remount protection taken */
85 bool fh_no_wcc; /* no wcc data needed */
86 bool fh_no_atomic_attr;
87 /*
88 * wcc data is not atomic with
89 * operation
90 */
91 int fh_flags; /* FH flags */
92 bool fh_post_saved; /* post-op attrs saved */
93 bool fh_pre_saved; /* pre-op attrs saved */
94
95 /* Pre-op attributes saved when inode is locked */
96 __u64 fh_pre_size; /* size before operation */
97 struct timespec64 fh_pre_mtime; /* mtime before oper */
98 struct timespec64 fh_pre_ctime; /* ctime before oper */
99 /*
100 * pre-op nfsv4 change attr: note must check IS_I_VERSION(inode)
101 * to find out if it is valid.
102 */
103 u64 fh_pre_change;
104
105 /* Post-op attributes saved in fh_fill_post_attrs() */
106 struct kstat fh_post_attr; /* full attrs after operation */
107 u64 fh_post_change; /* nfsv4 change; see above */
108 } svc_fh;
109 #define NFSD4_FH_FOREIGN (1<<0)
110 #define SET_FH_FLAG(c, f) ((c)->fh_flags |= (f))
111 #define HAS_FH_FLAG(c, f) ((c)->fh_flags & (f))
112
113 enum nfsd_fsid {
114 FSID_DEV = 0,
115 FSID_NUM,
116 FSID_MAJOR_MINOR,
117 FSID_ENCODE_DEV,
118 FSID_UUID4_INUM,
119 FSID_UUID8,
120 FSID_UUID16,
121 FSID_UUID16_INUM,
122 };
123
124 enum fsid_source {
125 FSIDSOURCE_DEV,
126 FSIDSOURCE_FSID,
127 FSIDSOURCE_UUID,
128 };
129 extern enum fsid_source fsid_source(const struct svc_fh *fhp);
130
131
132 /*
133 * This might look a little large to "inline" but in all calls except
134 * one, 'vers' is constant so moste of the function disappears.
135 *
136 * In some cases the values are considered to be host endian and in
137 * others, net endian. fsidv is always considered to be u32 as the
138 * callers don't know which it will be. So we must use __force to keep
139 * sparse from complaining. Since these values are opaque to the
140 * client, that shouldn't be a problem.
141 */
mk_fsid(int vers,u32 * fsidv,dev_t dev,ino_t ino,u32 fsid,unsigned char * uuid)142 static inline void mk_fsid(int vers, u32 *fsidv, dev_t dev, ino_t ino,
143 u32 fsid, unsigned char *uuid)
144 {
145 u32 *up;
146 switch(vers) {
147 case FSID_DEV:
148 fsidv[0] = (__force __u32)htonl((MAJOR(dev)<<16) |
149 MINOR(dev));
150 fsidv[1] = ino_t_to_u32(ino);
151 break;
152 case FSID_NUM:
153 fsidv[0] = fsid;
154 break;
155 case FSID_MAJOR_MINOR:
156 fsidv[0] = (__force __u32)htonl(MAJOR(dev));
157 fsidv[1] = (__force __u32)htonl(MINOR(dev));
158 fsidv[2] = ino_t_to_u32(ino);
159 break;
160
161 case FSID_ENCODE_DEV:
162 fsidv[0] = new_encode_dev(dev);
163 fsidv[1] = ino_t_to_u32(ino);
164 break;
165
166 case FSID_UUID4_INUM:
167 /* 4 byte fsid and inode number */
168 up = (u32*)uuid;
169 fsidv[0] = ino_t_to_u32(ino);
170 fsidv[1] = up[0] ^ up[1] ^ up[2] ^ up[3];
171 break;
172
173 case FSID_UUID8:
174 /* 8 byte fsid */
175 up = (u32*)uuid;
176 fsidv[0] = up[0] ^ up[2];
177 fsidv[1] = up[1] ^ up[3];
178 break;
179
180 case FSID_UUID16:
181 /* 16 byte fsid - NFSv3+ only */
182 memcpy(fsidv, uuid, 16);
183 break;
184
185 case FSID_UUID16_INUM:
186 /* 8 byte inode and 16 byte fsid */
187 *(u64*)fsidv = (u64)ino;
188 memcpy(fsidv+2, uuid, 16);
189 break;
190 default: BUG();
191 }
192 }
193
key_len(int type)194 static inline int key_len(int type)
195 {
196 switch(type) {
197 case FSID_DEV: return 8;
198 case FSID_NUM: return 4;
199 case FSID_MAJOR_MINOR: return 12;
200 case FSID_ENCODE_DEV: return 8;
201 case FSID_UUID4_INUM: return 8;
202 case FSID_UUID8: return 8;
203 case FSID_UUID16: return 16;
204 case FSID_UUID16_INUM: return 24;
205 default: return 0;
206 }
207 }
208
209 /*
210 * Shorthand for dprintk()'s
211 */
212 extern char * SVCFH_fmt(struct svc_fh *fhp);
213
214 /*
215 * Function prototypes
216 */
217 __be32 fh_verify(struct svc_rqst *, struct svc_fh *, umode_t, int);
218 __be32 fh_compose(struct svc_fh *, struct svc_export *, struct dentry *, struct svc_fh *);
219 __be32 fh_update(struct svc_fh *);
220 void fh_put(struct svc_fh *);
221
222 static __inline__ struct svc_fh *
fh_copy(struct svc_fh * dst,struct svc_fh * src)223 fh_copy(struct svc_fh *dst, struct svc_fh *src)
224 {
225 WARN_ON(src->fh_dentry);
226
227 *dst = *src;
228 return dst;
229 }
230
231 static inline void
fh_copy_shallow(struct knfsd_fh * dst,struct knfsd_fh * src)232 fh_copy_shallow(struct knfsd_fh *dst, struct knfsd_fh *src)
233 {
234 dst->fh_size = src->fh_size;
235 memcpy(&dst->fh_raw, &src->fh_raw, src->fh_size);
236 }
237
238 static __inline__ struct svc_fh *
fh_init(struct svc_fh * fhp,int maxsize)239 fh_init(struct svc_fh *fhp, int maxsize)
240 {
241 memset(fhp, 0, sizeof(*fhp));
242 fhp->fh_maxsize = maxsize;
243 return fhp;
244 }
245
fh_match(struct knfsd_fh * fh1,struct knfsd_fh * fh2)246 static inline bool fh_match(struct knfsd_fh *fh1, struct knfsd_fh *fh2)
247 {
248 if (fh1->fh_size != fh2->fh_size)
249 return false;
250 if (memcmp(fh1->fh_raw, fh2->fh_raw, fh1->fh_size) != 0)
251 return false;
252 return true;
253 }
254
fh_fsid_match(struct knfsd_fh * fh1,struct knfsd_fh * fh2)255 static inline bool fh_fsid_match(struct knfsd_fh *fh1, struct knfsd_fh *fh2)
256 {
257 if (fh1->fh_fsid_type != fh2->fh_fsid_type)
258 return false;
259 if (memcmp(fh1->fh_fsid, fh2->fh_fsid, key_len(fh1->fh_fsid_type)) != 0)
260 return false;
261 return true;
262 }
263
264 #ifdef CONFIG_CRC32
265 /**
266 * knfsd_fh_hash - calculate the crc32 hash for the filehandle
267 * @fh - pointer to filehandle
268 *
269 * returns a crc32 hash for the filehandle that is compatible with
270 * the one displayed by "wireshark".
271 */
knfsd_fh_hash(const struct knfsd_fh * fh)272 static inline u32 knfsd_fh_hash(const struct knfsd_fh *fh)
273 {
274 return ~crc32_le(0xFFFFFFFF, fh->fh_raw, fh->fh_size);
275 }
276 #else
knfsd_fh_hash(const struct knfsd_fh * fh)277 static inline u32 knfsd_fh_hash(const struct knfsd_fh *fh)
278 {
279 return 0;
280 }
281 #endif
282
283 /**
284 * fh_clear_pre_post_attrs - Reset pre/post attributes
285 * @fhp: file handle to be updated
286 *
287 */
fh_clear_pre_post_attrs(struct svc_fh * fhp)288 static inline void fh_clear_pre_post_attrs(struct svc_fh *fhp)
289 {
290 fhp->fh_post_saved = false;
291 fhp->fh_pre_saved = false;
292 }
293
294 /*
295 * We could use i_version alone as the change attribute. However,
296 * i_version can go backwards after a reboot. On its own that doesn't
297 * necessarily cause a problem, but if i_version goes backwards and then
298 * is incremented again it could reuse a value that was previously used
299 * before boot, and a client who queried the two values might
300 * incorrectly assume nothing changed.
301 *
302 * By using both ctime and the i_version counter we guarantee that as
303 * long as time doesn't go backwards we never reuse an old value.
304 */
nfsd4_change_attribute(struct kstat * stat,struct inode * inode)305 static inline u64 nfsd4_change_attribute(struct kstat *stat,
306 struct inode *inode)
307 {
308 if (inode->i_sb->s_export_op->fetch_iversion)
309 return inode->i_sb->s_export_op->fetch_iversion(inode);
310 else if (IS_I_VERSION(inode)) {
311 u64 chattr;
312
313 chattr = stat->ctime.tv_sec;
314 chattr <<= 30;
315 chattr += stat->ctime.tv_nsec;
316 chattr += inode_query_iversion(inode);
317 return chattr;
318 } else
319 return time_to_chattr(&stat->ctime);
320 }
321
322 extern void fh_fill_pre_attrs(struct svc_fh *fhp);
323 extern void fh_fill_post_attrs(struct svc_fh *fhp);
324 extern void fh_fill_both_attrs(struct svc_fh *fhp);
325 #endif /* _LINUX_NFSD_NFSFH_H */
326