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 62 static inline u32 *fh_fsid(const struct knfsd_fh *fh) 63 { 64 return (u32 *)&fh->fh_raw[4]; 65 } 66 67 static inline __u32 ino_t_to_u32(ino_t ino) 68 { 69 return (__u32) ino; 70 } 71 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(const struct svc_fh *fhp); 135 136 137 /* 138 * This might look a little large to "inline" but in all calls except 139 * one, 'vers' is constant so moste of the function disappears. 140 * 141 * In some cases the values are considered to be host endian and in 142 * others, net endian. fsidv is always considered to be u32 as the 143 * callers don't know which it will be. So we must use __force to keep 144 * sparse from complaining. Since these values are opaque to the 145 * client, that shouldn't be a problem. 146 */ 147 static inline void mk_fsid(int vers, u32 *fsidv, dev_t dev, ino_t ino, 148 u32 fsid, unsigned char *uuid) 149 { 150 u32 *up; 151 switch(vers) { 152 case FSID_DEV: 153 fsidv[0] = (__force __u32)htonl((MAJOR(dev)<<16) | 154 MINOR(dev)); 155 fsidv[1] = ino_t_to_u32(ino); 156 break; 157 case FSID_NUM: 158 fsidv[0] = fsid; 159 break; 160 case FSID_MAJOR_MINOR: 161 fsidv[0] = (__force __u32)htonl(MAJOR(dev)); 162 fsidv[1] = (__force __u32)htonl(MINOR(dev)); 163 fsidv[2] = ino_t_to_u32(ino); 164 break; 165 166 case FSID_ENCODE_DEV: 167 fsidv[0] = new_encode_dev(dev); 168 fsidv[1] = ino_t_to_u32(ino); 169 break; 170 171 case FSID_UUID4_INUM: 172 /* 4 byte fsid and inode number */ 173 up = (u32*)uuid; 174 fsidv[0] = ino_t_to_u32(ino); 175 fsidv[1] = up[0] ^ up[1] ^ up[2] ^ up[3]; 176 break; 177 178 case FSID_UUID8: 179 /* 8 byte fsid */ 180 up = (u32*)uuid; 181 fsidv[0] = up[0] ^ up[2]; 182 fsidv[1] = up[1] ^ up[3]; 183 break; 184 185 case FSID_UUID16: 186 /* 16 byte fsid - NFSv3+ only */ 187 memcpy(fsidv, uuid, 16); 188 break; 189 190 case FSID_UUID16_INUM: 191 /* 8 byte inode and 16 byte fsid */ 192 *(u64*)fsidv = (u64)ino; 193 memcpy(fsidv+2, uuid, 16); 194 break; 195 default: BUG(); 196 } 197 } 198 199 static inline int key_len(int type) 200 { 201 switch(type) { 202 case FSID_DEV: return 8; 203 case FSID_NUM: return 4; 204 case FSID_MAJOR_MINOR: return 12; 205 case FSID_ENCODE_DEV: return 8; 206 case FSID_UUID4_INUM: return 8; 207 case FSID_UUID8: return 8; 208 case FSID_UUID16: return 16; 209 case FSID_UUID16_INUM: return 24; 210 default: return 0; 211 } 212 } 213 214 /* 215 * Shorthand for dprintk()'s 216 */ 217 extern char * SVCFH_fmt(struct svc_fh *fhp); 218 219 /* 220 * Function prototypes 221 */ 222 __be32 fh_verify(struct svc_rqst *, struct svc_fh *, umode_t, int); 223 __be32 fh_verify_local(struct net *, struct svc_cred *, struct auth_domain *, 224 struct svc_fh *, umode_t, int); 225 __be32 fh_getattr(const struct svc_fh *fhp, struct kstat *stat); 226 __be32 fh_compose(struct svc_fh *, struct svc_export *, struct dentry *, struct svc_fh *); 227 __be32 fh_update(struct svc_fh *); 228 void fh_put(struct svc_fh *); 229 230 static __inline__ struct svc_fh * 231 fh_copy(struct svc_fh *dst, const struct svc_fh *src) 232 { 233 WARN_ON(src->fh_dentry); 234 235 *dst = *src; 236 return dst; 237 } 238 239 static inline void 240 fh_copy_shallow(struct knfsd_fh *dst, const struct knfsd_fh *src) 241 { 242 dst->fh_size = src->fh_size; 243 memcpy(&dst->fh_raw, &src->fh_raw, src->fh_size); 244 } 245 246 static __inline__ struct svc_fh * 247 fh_init(struct svc_fh *fhp, int maxsize) 248 { 249 memset(fhp, 0, sizeof(*fhp)); 250 fhp->fh_maxsize = maxsize; 251 return fhp; 252 } 253 254 static inline bool fh_match(const struct knfsd_fh *fh1, 255 const struct knfsd_fh *fh2) 256 { 257 if (fh1->fh_size != fh2->fh_size) 258 return false; 259 if (memcmp(fh1->fh_raw, fh2->fh_raw, fh1->fh_size) != 0) 260 return false; 261 return true; 262 } 263 264 static inline bool fh_fsid_match(const struct knfsd_fh *fh1, 265 const struct knfsd_fh *fh2) 266 { 267 u32 *fsid1 = fh_fsid(fh1); 268 u32 *fsid2 = fh_fsid(fh2); 269 270 if (fh1->fh_fsid_type != fh2->fh_fsid_type) 271 return false; 272 if (memcmp(fsid1, fsid2, key_len(fh1->fh_fsid_type)) != 0) 273 return false; 274 return true; 275 } 276 277 /** 278 * fh_want_write - Get write access to an export 279 * @fhp: File handle of file to be written 280 * 281 * Caller must invoke fh_drop_write() when its write operation 282 * is complete. 283 * 284 * Returns 0 if the file handle's export can be written to. Otherwise 285 * the export is not prepared for updates, and the returned negative 286 * errno value reflects the reason for the failure. 287 */ 288 static inline int fh_want_write(struct svc_fh *fhp) 289 { 290 int ret; 291 292 if (fhp->fh_want_write) 293 return 0; 294 ret = mnt_want_write(fhp->fh_export->ex_path.mnt); 295 if (!ret) 296 fhp->fh_want_write = true; 297 return ret; 298 } 299 300 /** 301 * fh_drop_write - Release write access on an export 302 * @fhp: File handle of file on which fh_want_write() was previously called 303 */ 304 static inline void fh_drop_write(struct svc_fh *fhp) 305 { 306 if (fhp->fh_want_write) { 307 fhp->fh_want_write = false; 308 mnt_drop_write(fhp->fh_export->ex_path.mnt); 309 } 310 } 311 312 /** 313 * knfsd_fh_hash - calculate the crc32 hash for the filehandle 314 * @fh - pointer to filehandle 315 * 316 * returns a crc32 hash for the filehandle that is compatible with 317 * the one displayed by "wireshark". 318 */ 319 static inline u32 knfsd_fh_hash(const struct knfsd_fh *fh) 320 { 321 return ~crc32_le(0xFFFFFFFF, fh->fh_raw, fh->fh_size); 322 } 323 324 /** 325 * fh_clear_pre_post_attrs - Reset pre/post attributes 326 * @fhp: file handle to be updated 327 * 328 */ 329 static inline void fh_clear_pre_post_attrs(struct svc_fh *fhp) 330 { 331 fhp->fh_post_saved = false; 332 fhp->fh_pre_saved = false; 333 } 334 335 u64 nfsd4_change_attribute(const struct kstat *stat); 336 __be32 __must_check fh_fill_pre_attrs(struct svc_fh *fhp); 337 __be32 fh_fill_post_attrs(struct svc_fh *fhp); 338 __be32 __must_check fh_fill_both_attrs(struct svc_fh *fhp); 339 #endif /* _LINUX_NFSD_NFSFH_H */ 340