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 bool fh_post_saved; /* post-op attrs saved */ 94 bool fh_pre_saved; /* pre-op attrs saved */ 95 96 /* Pre-op attributes saved during fh_lock */ 97 __u64 fh_pre_size; /* size before operation */ 98 struct timespec64 fh_pre_mtime; /* mtime before oper */ 99 struct timespec64 fh_pre_ctime; /* ctime before oper */ 100 /* 101 * pre-op nfsv4 change attr: note must check IS_I_VERSION(inode) 102 * to find out if it is valid. 103 */ 104 u64 fh_pre_change; 105 106 /* Post-op attributes saved in fh_unlock */ 107 struct kstat fh_post_attr; /* full attrs after operation */ 108 u64 fh_post_change; /* nfsv4 change; see above */ 109 } svc_fh; 110 #define NFSD4_FH_FOREIGN (1<<0) 111 #define SET_FH_FLAG(c, f) ((c)->fh_flags |= (f)) 112 #define HAS_FH_FLAG(c, f) ((c)->fh_flags & (f)) 113 114 enum nfsd_fsid { 115 FSID_DEV = 0, 116 FSID_NUM, 117 FSID_MAJOR_MINOR, 118 FSID_ENCODE_DEV, 119 FSID_UUID4_INUM, 120 FSID_UUID8, 121 FSID_UUID16, 122 FSID_UUID16_INUM, 123 }; 124 125 enum fsid_source { 126 FSIDSOURCE_DEV, 127 FSIDSOURCE_FSID, 128 FSIDSOURCE_UUID, 129 }; 130 extern enum fsid_source fsid_source(const struct svc_fh *fhp); 131 132 133 /* 134 * This might look a little large to "inline" but in all calls except 135 * one, 'vers' is constant so moste of the function disappears. 136 * 137 * In some cases the values are considered to be host endian and in 138 * others, net endian. fsidv is always considered to be u32 as the 139 * callers don't know which it will be. So we must use __force to keep 140 * sparse from complaining. Since these values are opaque to the 141 * client, that shouldn't be a problem. 142 */ 143 static inline void mk_fsid(int vers, u32 *fsidv, dev_t dev, ino_t ino, 144 u32 fsid, unsigned char *uuid) 145 { 146 u32 *up; 147 switch(vers) { 148 case FSID_DEV: 149 fsidv[0] = (__force __u32)htonl((MAJOR(dev)<<16) | 150 MINOR(dev)); 151 fsidv[1] = ino_t_to_u32(ino); 152 break; 153 case FSID_NUM: 154 fsidv[0] = fsid; 155 break; 156 case FSID_MAJOR_MINOR: 157 fsidv[0] = (__force __u32)htonl(MAJOR(dev)); 158 fsidv[1] = (__force __u32)htonl(MINOR(dev)); 159 fsidv[2] = ino_t_to_u32(ino); 160 break; 161 162 case FSID_ENCODE_DEV: 163 fsidv[0] = new_encode_dev(dev); 164 fsidv[1] = ino_t_to_u32(ino); 165 break; 166 167 case FSID_UUID4_INUM: 168 /* 4 byte fsid and inode number */ 169 up = (u32*)uuid; 170 fsidv[0] = ino_t_to_u32(ino); 171 fsidv[1] = up[0] ^ up[1] ^ up[2] ^ up[3]; 172 break; 173 174 case FSID_UUID8: 175 /* 8 byte fsid */ 176 up = (u32*)uuid; 177 fsidv[0] = up[0] ^ up[2]; 178 fsidv[1] = up[1] ^ up[3]; 179 break; 180 181 case FSID_UUID16: 182 /* 16 byte fsid - NFSv3+ only */ 183 memcpy(fsidv, uuid, 16); 184 break; 185 186 case FSID_UUID16_INUM: 187 /* 8 byte inode and 16 byte fsid */ 188 *(u64*)fsidv = (u64)ino; 189 memcpy(fsidv+2, uuid, 16); 190 break; 191 default: BUG(); 192 } 193 } 194 195 static inline int key_len(int type) 196 { 197 switch(type) { 198 case FSID_DEV: return 8; 199 case FSID_NUM: return 4; 200 case FSID_MAJOR_MINOR: return 12; 201 case FSID_ENCODE_DEV: return 8; 202 case FSID_UUID4_INUM: return 8; 203 case FSID_UUID8: return 8; 204 case FSID_UUID16: return 16; 205 case FSID_UUID16_INUM: return 24; 206 default: return 0; 207 } 208 } 209 210 /* 211 * Shorthand for dprintk()'s 212 */ 213 extern char * SVCFH_fmt(struct svc_fh *fhp); 214 215 /* 216 * Function prototypes 217 */ 218 __be32 fh_verify(struct svc_rqst *, struct svc_fh *, umode_t, int); 219 __be32 fh_compose(struct svc_fh *, struct svc_export *, struct dentry *, struct svc_fh *); 220 __be32 fh_update(struct svc_fh *); 221 void fh_put(struct svc_fh *); 222 223 static __inline__ struct svc_fh * 224 fh_copy(struct svc_fh *dst, struct svc_fh *src) 225 { 226 WARN_ON(src->fh_dentry || src->fh_locked); 227 228 *dst = *src; 229 return dst; 230 } 231 232 static inline void 233 fh_copy_shallow(struct knfsd_fh *dst, struct knfsd_fh *src) 234 { 235 dst->fh_size = src->fh_size; 236 memcpy(&dst->fh_raw, &src->fh_raw, src->fh_size); 237 } 238 239 static __inline__ struct svc_fh * 240 fh_init(struct svc_fh *fhp, int maxsize) 241 { 242 memset(fhp, 0, sizeof(*fhp)); 243 fhp->fh_maxsize = maxsize; 244 return fhp; 245 } 246 247 static inline bool fh_match(struct knfsd_fh *fh1, struct knfsd_fh *fh2) 248 { 249 if (fh1->fh_size != fh2->fh_size) 250 return false; 251 if (memcmp(fh1->fh_raw, fh2->fh_raw, fh1->fh_size) != 0) 252 return false; 253 return true; 254 } 255 256 static inline bool fh_fsid_match(struct knfsd_fh *fh1, struct knfsd_fh *fh2) 257 { 258 if (fh1->fh_fsid_type != fh2->fh_fsid_type) 259 return false; 260 if (memcmp(fh1->fh_fsid, fh2->fh_fsid, key_len(fh1->fh_fsid_type)) != 0) 261 return false; 262 return true; 263 } 264 265 #ifdef CONFIG_CRC32 266 /** 267 * knfsd_fh_hash - calculate the crc32 hash for the filehandle 268 * @fh - pointer to filehandle 269 * 270 * returns a crc32 hash for the filehandle that is compatible with 271 * the one displayed by "wireshark". 272 */ 273 static inline u32 knfsd_fh_hash(const struct knfsd_fh *fh) 274 { 275 return ~crc32_le(0xFFFFFFFF, fh->fh_raw, fh->fh_size); 276 } 277 #else 278 static inline u32 knfsd_fh_hash(const struct knfsd_fh *fh) 279 { 280 return 0; 281 } 282 #endif 283 284 /** 285 * fh_clear_pre_post_attrs - Reset pre/post attributes 286 * @fhp: file handle to be updated 287 * 288 */ 289 static inline void fh_clear_pre_post_attrs(struct svc_fh *fhp) 290 { 291 fhp->fh_post_saved = false; 292 fhp->fh_pre_saved = false; 293 } 294 295 /* 296 * We could use i_version alone as the change attribute. However, 297 * i_version can go backwards after a reboot. On its own that doesn't 298 * necessarily cause a problem, but if i_version goes backwards and then 299 * is incremented again it could reuse a value that was previously used 300 * before boot, and a client who queried the two values might 301 * incorrectly assume nothing changed. 302 * 303 * By using both ctime and the i_version counter we guarantee that as 304 * long as time doesn't go backwards we never reuse an old value. 305 */ 306 static inline u64 nfsd4_change_attribute(struct kstat *stat, 307 struct inode *inode) 308 { 309 if (inode->i_sb->s_export_op->fetch_iversion) 310 return inode->i_sb->s_export_op->fetch_iversion(inode); 311 else if (IS_I_VERSION(inode)) { 312 u64 chattr; 313 314 chattr = stat->ctime.tv_sec; 315 chattr <<= 30; 316 chattr += stat->ctime.tv_nsec; 317 chattr += inode_query_iversion(inode); 318 return chattr; 319 } else 320 return time_to_chattr(&stat->ctime); 321 } 322 323 extern void fh_fill_pre_attrs(struct svc_fh *fhp); 324 extern void fh_fill_post_attrs(struct svc_fh *fhp); 325 326 327 /* 328 * Lock a file handle/inode 329 * NOTE: both fh_lock and fh_unlock are done "by hand" in 330 * vfs.c:nfsd_rename as it needs to grab 2 i_mutex's at once 331 * so, any changes here should be reflected there. 332 */ 333 334 static inline void 335 fh_lock_nested(struct svc_fh *fhp, unsigned int subclass) 336 { 337 struct dentry *dentry = fhp->fh_dentry; 338 struct inode *inode; 339 340 BUG_ON(!dentry); 341 342 if (fhp->fh_locked) { 343 printk(KERN_WARNING "fh_lock: %pd2 already locked!\n", 344 dentry); 345 return; 346 } 347 348 inode = d_inode(dentry); 349 inode_lock_nested(inode, subclass); 350 fh_fill_pre_attrs(fhp); 351 fhp->fh_locked = true; 352 } 353 354 static inline void 355 fh_lock(struct svc_fh *fhp) 356 { 357 fh_lock_nested(fhp, I_MUTEX_NORMAL); 358 } 359 360 /* 361 * Unlock a file handle/inode 362 */ 363 static inline void 364 fh_unlock(struct svc_fh *fhp) 365 { 366 if (fhp->fh_locked) { 367 fh_fill_post_attrs(fhp); 368 inode_unlock(d_inode(fhp->fh_dentry)); 369 fhp->fh_locked = false; 370 } 371 } 372 373 #endif /* _LINUX_NFSD_NFSFH_H */ 374