fs/nfsd/nfsfh.h

   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 <uapi/linux/nfsd/nfsfh.h>
  14 #include <linux/iversion.h>
  15
  16 static inline __u32 ino_t_to_u32(ino_t ino)
  17 {
  18         return (__u32) ino;
  19 }
  20
  21 static inline ino_t u32_to_ino_t(__u32 uino)
  22 {
  23         return (ino_t) uino;
  24 }
  25
  26 /*
  27  * This is the internal representation of an NFS handle used in knfsd.
  28  * pre_mtime/post_version will be used to support wcc_attr's in NFSv3.
  29  */
  30 typedef struct svc_fh {
  31         struct knfsd_fh         fh_handle;      /* FH data */
  32         int                     fh_maxsize;     /* max size for fh_handle */
  33         struct dentry *         fh_dentry;      /* validated dentry */
  34         struct svc_export *     fh_export;      /* export pointer */
  35
  36         bool                    fh_locked;      /* inode locked by us */
  37         bool                    fh_want_write;  /* remount protection taken */
  38         bool                    fh_no_wcc;      /* no wcc data needed */
  39         bool                    fh_no_atomic_attr;
  40                                                 /*
  41                                                  * wcc data is not atomic with
  42                                                  * operation
  43                                                  */
  44         int                     fh_flags;       /* FH flags */
  45 #ifdef CONFIG_NFSD_V3
  46         bool                    fh_post_saved;  /* post-op attrs saved */
  47         bool                    fh_pre_saved;   /* pre-op attrs saved */
  48
  49         /* Pre-op attributes saved during fh_lock */
  50         __u64                   fh_pre_size;    /* size before operation */
  51         struct timespec64       fh_pre_mtime;   /* mtime before oper */
  52         struct timespec64       fh_pre_ctime;   /* ctime before oper */
  53         /*
  54          * pre-op nfsv4 change attr: note must check IS_I_VERSION(inode)
  55          *  to find out if it is valid.
  56          */
  57         u64                     fh_pre_change;
  58
  59         /* Post-op attributes saved in fh_unlock */
  60         struct kstat            fh_post_attr;   /* full attrs after operation */
  61         u64                     fh_post_change; /* nfsv4 change; see above */
  62 #endif /* CONFIG_NFSD_V3 */
  63 } svc_fh;
  64 #define NFSD4_FH_FOREIGN (1<<0)
  65 #define SET_FH_FLAG(c, f) ((c)->fh_flags |= (f))
  66 #define HAS_FH_FLAG(c, f) ((c)->fh_flags & (f))
  67
  68 enum nfsd_fsid {
  69         FSID_DEV = 0,
  70         FSID_NUM,
  71         FSID_MAJOR_MINOR,
  72         FSID_ENCODE_DEV,
  73         FSID_UUID4_INUM,
  74         FSID_UUID8,
  75         FSID_UUID16,
  76         FSID_UUID16_INUM,
  77 };
  78
  79 enum fsid_source {
  80         FSIDSOURCE_DEV,
  81         FSIDSOURCE_FSID,
  82         FSIDSOURCE_UUID,
  83 };
  84 extern enum fsid_source fsid_source(struct svc_fh *fhp);
  85
  86
  87 /*
  88  * This might look a little large to "inline" but in all calls except
  89  * one, 'vers' is constant so moste of the function disappears.
  90  *
  91  * In some cases the values are considered to be host endian and in
  92  * others, net endian. fsidv is always considered to be u32 as the
  93  * callers don't know which it will be. So we must use __force to keep
  94  * sparse from complaining. Since these values are opaque to the
  95  * client, that shouldn't be a problem.
  96  */
  97 static inline void mk_fsid(int vers, u32 *fsidv, dev_t dev, ino_t ino,
  98                            u32 fsid, unsigned char *uuid)
  99 {
 100         u32 *up;
 101         switch(vers) {
 102         case FSID_DEV:
 103                 fsidv[0] = (__force __u32)htonl((MAJOR(dev)<<16) |
 104                                  MINOR(dev));
 105                 fsidv[1] = ino_t_to_u32(ino);
 106                 break;
 107         case FSID_NUM:
 108                 fsidv[0] = fsid;
 109                 break;
 110         case FSID_MAJOR_MINOR:
 111                 fsidv[0] = (__force __u32)htonl(MAJOR(dev));
 112                 fsidv[1] = (__force __u32)htonl(MINOR(dev));
 113                 fsidv[2] = ino_t_to_u32(ino);
 114                 break;
 115
 116         case FSID_ENCODE_DEV:
 117                 fsidv[0] = new_encode_dev(dev);
 118                 fsidv[1] = ino_t_to_u32(ino);
 119                 break;
 120
 121         case FSID_UUID4_INUM:
 122                 /* 4 byte fsid and inode number */
 123                 up = (u32*)uuid;
 124                 fsidv[0] = ino_t_to_u32(ino);
 125                 fsidv[1] = up[0] ^ up[1] ^ up[2] ^ up[3];
 126                 break;
 127
 128         case FSID_UUID8:
 129                 /* 8 byte fsid  */
 130                 up = (u32*)uuid;
 131                 fsidv[0] = up[0] ^ up[2];
 132                 fsidv[1] = up[1] ^ up[3];
 133                 break;
 134
 135         case FSID_UUID16:
 136                 /* 16 byte fsid - NFSv3+ only */
 137                 memcpy(fsidv, uuid, 16);
 138                 break;
 139
 140         case FSID_UUID16_INUM:
 141                 /* 8 byte inode and 16 byte fsid */
 142                 *(u64*)fsidv = (u64)ino;
 143                 memcpy(fsidv+2, uuid, 16);
 144                 break;
 145         default: BUG();
 146         }
 147 }
 148
 149 static inline int key_len(int type)
 150 {
 151         switch(type) {
 152         case FSID_DEV:          return 8;
 153         case FSID_NUM:          return 4;
 154         case FSID_MAJOR_MINOR:  return 12;
 155         case FSID_ENCODE_DEV:   return 8;
 156         case FSID_UUID4_INUM:   return 8;
 157         case FSID_UUID8:        return 8;
 158         case FSID_UUID16:       return 16;
 159         case FSID_UUID16_INUM:  return 24;
 160         default: return 0;
 161         }
 162 }
 163
 164 /*
 165  * Shorthand for dprintk()'s
 166  */
 167 extern char * SVCFH_fmt(struct svc_fh *fhp);
 168
 169 /*
 170  * Function prototypes
 171  */
 172 __be32  fh_verify(struct svc_rqst *, struct svc_fh *, umode_t, int);
 173 __be32  fh_compose(struct svc_fh *, struct svc_export *, struct dentry *, struct svc_fh *);
 174 __be32  fh_update(struct svc_fh *);
 175 void    fh_put(struct svc_fh *);
 176
 177 static __inline__ struct svc_fh *
 178 fh_copy(struct svc_fh *dst, struct svc_fh *src)
 179 {
 180         WARN_ON(src->fh_dentry || src->fh_locked);
 181
 182         *dst = *src;
 183         return dst;
 184 }
 185
 186 static inline void
 187 fh_copy_shallow(struct knfsd_fh *dst, struct knfsd_fh *src)
 188 {
 189         dst->fh_size = src->fh_size;
 190         memcpy(&dst->fh_base, &src->fh_base, src->fh_size);
 191 }
 192
 193 static __inline__ struct svc_fh *
 194 fh_init(struct svc_fh *fhp, int maxsize)
 195 {
 196         memset(fhp, 0, sizeof(*fhp));
 197         fhp->fh_maxsize = maxsize;
 198         return fhp;
 199 }
 200
 201 static inline bool fh_match(struct knfsd_fh *fh1, struct knfsd_fh *fh2)
 202 {
 203         if (fh1->fh_size != fh2->fh_size)
 204                 return false;
 205         if (memcmp(fh1->fh_base.fh_pad, fh2->fh_base.fh_pad, fh1->fh_size) != 0)
 206                 return false;
 207         return true;
 208 }
 209
 210 static inline bool fh_fsid_match(struct knfsd_fh *fh1, struct knfsd_fh *fh2)
 211 {
 212         if (fh1->fh_fsid_type != fh2->fh_fsid_type)
 213                 return false;
 214         if (memcmp(fh1->fh_fsid, fh2->fh_fsid, key_len(fh1->fh_fsid_type)) != 0)
 215                 return false;
 216         return true;
 217 }
 218
 219 #ifdef CONFIG_CRC32
 220 /**
 221  * knfsd_fh_hash - calculate the crc32 hash for the filehandle
 222  * @fh - pointer to filehandle
 223  *
 224  * returns a crc32 hash for the filehandle that is compatible with
 225  * the one displayed by "wireshark".
 226  */
 227
 228 static inline u32
 229 knfsd_fh_hash(struct knfsd_fh *fh)
 230 {
 231         return ~crc32_le(0xFFFFFFFF, (unsigned char *)&fh->fh_base, fh->fh_size);
 232 }
 233 #else
 234 static inline u32
 235 knfsd_fh_hash(struct knfsd_fh *fh)
 236 {
 237         return 0;
 238 }
 239 #endif
 240
 241 #ifdef CONFIG_NFSD_V3
 242 /*
 243  * The wcc data stored in current_fh should be cleared
 244  * between compound ops.
 245  */
 246 static inline void
 247 fh_clear_wcc(struct svc_fh *fhp)
 248 {
 249         fhp->fh_post_saved = false;
 250         fhp->fh_pre_saved = false;
 251 }
 252
 253 /*
 254  * We could use i_version alone as the change attribute.  However,
 255  * i_version can go backwards after a reboot.  On its own that doesn't
 256  * necessarily cause a problem, but if i_version goes backwards and then
 257  * is incremented again it could reuse a value that was previously used
 258  * before boot, and a client who queried the two values might
 259  * incorrectly assume nothing changed.
 260  *
 261  * By using both ctime and the i_version counter we guarantee that as
 262  * long as time doesn't go backwards we never reuse an old value.
 263  */
 264 static inline u64 nfsd4_change_attribute(struct kstat *stat,
 265                                          struct inode *inode)
 266 {
 267         if (IS_I_VERSION(inode)) {
 268                 u64 chattr;
 269
 270                 chattr =  stat->ctime.tv_sec;
 271                 chattr <<= 30;
 272                 chattr += stat->ctime.tv_nsec;
 273                 chattr += inode_query_iversion(inode);
 274                 return chattr;
 275         } else
 276                 return time_to_chattr(&stat->ctime);
 277 }
 278
 279 extern void fill_pre_wcc(struct svc_fh *fhp);
 280 extern void fill_post_wcc(struct svc_fh *fhp);
 281 #else
 282 #define fh_clear_wcc(ignored)
 283 #define fill_pre_wcc(ignored)
 284 #define fill_post_wcc(notused)
 285 #endif /* CONFIG_NFSD_V3 */
 286
 287
 288 /*
 289  * Lock a file handle/inode
 290  * NOTE: both fh_lock and fh_unlock are done "by hand" in
 291  * vfs.c:nfsd_rename as it needs to grab 2 i_mutex's at once
 292  * so, any changes here should be reflected there.
 293  */
 294
 295 static inline void
 296 fh_lock_nested(struct svc_fh *fhp, unsigned int subclass)
 297 {
 298         struct dentry   *dentry = fhp->fh_dentry;
 299         struct inode    *inode;
 300
 301         BUG_ON(!dentry);
 302
 303         if (fhp->fh_locked) {
 304                 printk(KERN_WARNING "fh_lock: %pd2 already locked!\n",
 305                         dentry);
 306                 return;
 307         }
 308
 309         inode = d_inode(dentry);
 310         inode_lock_nested(inode, subclass);
 311         fill_pre_wcc(fhp);
 312         fhp->fh_locked = true;
 313 }
 314
 315 static inline void
 316 fh_lock(struct svc_fh *fhp)
 317 {
 318         fh_lock_nested(fhp, I_MUTEX_NORMAL);
 319 }
 320
 321 /*
 322  * Unlock a file handle/inode
 323  */
 324 static inline void
 325 fh_unlock(struct svc_fh *fhp)
 326 {
 327         if (fhp->fh_locked) {
 328                 fill_post_wcc(fhp);
 329                 inode_unlock(d_inode(fhp->fh_dentry));
 330                 fhp->fh_locked = false;
 331         }
 332 }
 333
 334 #endif /* _LINUX_NFSD_NFSFH_H */