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 64 static inline __u32 ino_t_to_u32(ino_t ino) 65 { 66 return (__u32) ino; 67 } 68 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 */ 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 } 196 197 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 * 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 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 * 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 } 248 249 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 } 257 258 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 */ 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 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 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 */ 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 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 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 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