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_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 */ 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 } 193 194 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 * 223 fh_copy(struct svc_fh *dst, const struct svc_fh *src) 224 { 225 WARN_ON(src->fh_dentry); 226 227 *dst = *src; 228 return dst; 229 } 230 231 static inline void 232 fh_copy_shallow(struct knfsd_fh *dst, const 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 * 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 } 245 246 static inline bool fh_match(const struct knfsd_fh *fh1, 247 const 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(const struct knfsd_fh *fh1, 257 const struct knfsd_fh *fh2) 258 { 259 if (fh1->fh_fsid_type != fh2->fh_fsid_type) 260 return false; 261 if (memcmp(fh1->fh_fsid, fh2->fh_fsid, key_len(fh1->fh_fsid_type)) != 0) 262 return false; 263 return true; 264 } 265 266 #ifdef CONFIG_CRC32 267 /** 268 * knfsd_fh_hash - calculate the crc32 hash for the filehandle 269 * @fh - pointer to filehandle 270 * 271 * returns a crc32 hash for the filehandle that is compatible with 272 * the one displayed by "wireshark". 273 */ 274 static inline u32 knfsd_fh_hash(const struct knfsd_fh *fh) 275 { 276 return ~crc32_le(0xFFFFFFFF, fh->fh_raw, fh->fh_size); 277 } 278 #else 279 static inline u32 knfsd_fh_hash(const struct knfsd_fh *fh) 280 { 281 return 0; 282 } 283 #endif 284 285 /** 286 * fh_clear_pre_post_attrs - Reset pre/post attributes 287 * @fhp: file handle to be updated 288 * 289 */ 290 static inline void fh_clear_pre_post_attrs(struct svc_fh *fhp) 291 { 292 fhp->fh_post_saved = false; 293 fhp->fh_pre_saved = false; 294 } 295 296 /* 297 * We could use i_version alone as the change attribute. However, 298 * i_version can go backwards after a reboot. On its own that doesn't 299 * necessarily cause a problem, but if i_version goes backwards and then 300 * is incremented again it could reuse a value that was previously used 301 * before boot, and a client who queried the two values might 302 * incorrectly assume nothing changed. 303 * 304 * By using both ctime and the i_version counter we guarantee that as 305 * long as time doesn't go backwards we never reuse an old value. 306 */ 307 static inline u64 nfsd4_change_attribute(struct kstat *stat, 308 struct inode *inode) 309 { 310 if (inode->i_sb->s_export_op->fetch_iversion) 311 return inode->i_sb->s_export_op->fetch_iversion(inode); 312 else if (IS_I_VERSION(inode)) { 313 u64 chattr; 314 315 chattr = stat->ctime.tv_sec; 316 chattr <<= 30; 317 chattr += stat->ctime.tv_nsec; 318 chattr += inode_query_iversion(inode); 319 return chattr; 320 } else 321 return time_to_chattr(&stat->ctime); 322 } 323 324 extern void fh_fill_pre_attrs(struct svc_fh *fhp); 325 extern void fh_fill_post_attrs(struct svc_fh *fhp); 326 extern void fh_fill_both_attrs(struct svc_fh *fhp); 327 #endif /* _LINUX_NFSD_NFSFH_H */ 328