include/linux/nfsd/nfsfh.h

   1 /*
   2  * include/linux/nfsd/nfsfh.h
   3  *
   4  * This file describes the layout of the file handles as passed
   5  * over the wire.
   6  *
   7  * Earlier versions of knfsd used to sign file handles using keyed MD5
   8  * or SHA. I've removed this code, because it doesn't give you more
   9  * security than blocking external access to port 2049 on your firewall.
  10  *
  11  * Copyright (C) 1995, 1996, 1997 Olaf Kirch <okir@monad.swb.de>
  12  */
  13
  14 #ifndef _LINUX_NFSD_FH_H
  15 #define _LINUX_NFSD_FH_H
  16
  17 # include <linux/types.h>
  18 #ifdef __KERNEL__
  19 # include <linux/string.h>
  20 # include <linux/fs.h>
  21 #endif
  22 #include <linux/nfsd/const.h>
  23 #include <linux/nfsd/debug.h>
  24
  25 /*
  26  * This is the old "dentry style" Linux NFSv2 file handle.
  27  *
  28  * The xino and xdev fields are currently used to transport the
  29  * ino/dev of the exported inode.
  30  */
  31 struct nfs_fhbase_old {
  32         __u32           fb_dcookie;     /* dentry cookie - always 0xfeebbaca */
  33         __u32           fb_ino;         /* our inode number */
  34         __u32           fb_dirino;      /* dir inode number, 0 for directories */
  35         __u32           fb_dev;         /* our device */
  36         __u32           fb_xdev;
  37         __u32           fb_xino;
  38         __u32           fb_generation;
  39 };
  40
  41 /*
  42  * This is the new flexible, extensible style NFSv2/v3 file handle.
  43  * by Neil Brown <neilb@cse.unsw.edu.au> - March 2000
  44  *
  45  * The file handle is seens as a list of 4byte words.
  46  * The first word contains a version number (1) and four descriptor bytes
  47  * that tell how the remaining 3 variable length fields should be handled.
  48  * These three bytes are auth_type, fsid_type and fileid_type.
  49  *
  50  * All 4byte values are in host-byte-order.
  51  *
  52  * The auth_type field specifies how the filehandle can be authenticated
  53  * This might allow a file to be confirmed to be in a writable part of a
  54  * filetree without checking the path from it upto the root.
  55  * Current values:
  56  *     0  - No authentication.  fb_auth is 0 bytes long
  57  * Possible future values:
  58  *     1  - 4 bytes taken from MD5 hash of the remainer of the file handle
  59  *          prefixed by a secret and with the important export flags.
  60  *
  61  * The fsid_type identifies how the filesystem (or export point) is
  62  *    encoded.
  63  *  Current values:
  64  *     0  - 4 byte device id (ms-2-bytes major, ls-2-bytes minor), 4byte inode number
  65  *        NOTE: we cannot use the kdev_t device id value, because kdev_t.h
  66  *              says we mustn't.  We must break it up and reassemble.
  67  *     1  - 4 byte user specified identifier
  68  *     2  - 4 byte major, 4 byte minor, 4 byte inode number - DEPRECATED
  69  *     3  - 4 byte device id, encoded for user-space, 4 byte inode number
  70  *     4  - 4 byte inode number and 4 byte uuid
  71  *     5  - 8 byte uuid
  72  *     6  - 16 byte uuid
  73  *     7  - 8 byte inode number and 16 byte uuid
  74  *
  75  * The fileid_type identified how the file within the filesystem is encoded.
  76  * This is (will be) passed to, and set by, the underlying filesystem if it supports
  77  * filehandle operations.  The filesystem must not use the value '0' or '0xff' and may
  78  * only use the values 1 and 2 as defined below:
  79  *  Current values:
  80  *    0   - The root, or export point, of the filesystem.  fb_fileid is 0 bytes.
  81  *    1   - 32bit inode number, 32 bit generation number.
  82  *    2   - 32bit inode number, 32 bit generation number, 32 bit parent directory inode number.
  83  *
  84  */
  85 struct nfs_fhbase_new {
  86         __u8            fb_version;     /* == 1, even => nfs_fhbase_old */
  87         __u8            fb_auth_type;
  88         __u8            fb_fsid_type;
  89         __u8            fb_fileid_type;
  90         __u32           fb_auth[1];
  91 /*      __u32           fb_fsid[0]; floating */
  92 /*      __u32           fb_fileid[0]; floating */
  93 };
  94
  95 struct knfsd_fh {
  96         unsigned int    fh_size;        /* significant for NFSv3.
  97                                          * Points to the current size while building
  98                                          * a new file handle
  99                                          */
 100         union {
 101                 struct nfs_fhbase_old   fh_old;
 102                 __u32                   fh_pad[NFS4_FHSIZE/4];
 103                 struct nfs_fhbase_new   fh_new;
 104         } fh_base;
 105 };
 106
 107 #define ofh_dcookie             fh_base.fh_old.fb_dcookie
 108 #define ofh_ino                 fh_base.fh_old.fb_ino
 109 #define ofh_dirino              fh_base.fh_old.fb_dirino
 110 #define ofh_dev                 fh_base.fh_old.fb_dev
 111 #define ofh_xdev                fh_base.fh_old.fb_xdev
 112 #define ofh_xino                fh_base.fh_old.fb_xino
 113 #define ofh_generation          fh_base.fh_old.fb_generation
 114
 115 #define fh_version              fh_base.fh_new.fb_version
 116 #define fh_fsid_type            fh_base.fh_new.fb_fsid_type
 117 #define fh_auth_type            fh_base.fh_new.fb_auth_type
 118 #define fh_fileid_type          fh_base.fh_new.fb_fileid_type
 119 #define fh_auth                 fh_base.fh_new.fb_auth
 120 #define fh_fsid                 fh_base.fh_new.fb_auth
 121
 122 #ifdef __KERNEL__
 123
 124 static inline __u32 ino_t_to_u32(ino_t ino)
 125 {
 126         return (__u32) ino;
 127 }
 128
 129 static inline ino_t u32_to_ino_t(__u32 uino)
 130 {
 131         return (ino_t) uino;
 132 }
 133
 134 /*
 135  * This is the internal representation of an NFS handle used in knfsd.
 136  * pre_mtime/post_version will be used to support wcc_attr's in NFSv3.
 137  */
 138 typedef struct svc_fh {
 139         struct knfsd_fh         fh_handle;      /* FH data */
 140         struct dentry *         fh_dentry;      /* validated dentry */
 141         struct svc_export *     fh_export;      /* export pointer */
 142         int                     fh_maxsize;     /* max size for fh_handle */
 143
 144         unsigned char           fh_locked;      /* inode locked by us */
 145
 146 #ifdef CONFIG_NFSD_V3
 147         unsigned char           fh_post_saved;  /* post-op attrs saved */
 148         unsigned char           fh_pre_saved;   /* pre-op attrs saved */
 149
 150         /* Pre-op attributes saved during fh_lock */
 151         __u64                   fh_pre_size;    /* size before operation */
 152         struct timespec         fh_pre_mtime;   /* mtime before oper */
 153         struct timespec         fh_pre_ctime;   /* ctime before oper */
 154         /*
 155          * pre-op nfsv4 change attr: note must check IS_I_VERSION(inode)
 156          *  to find out if it is valid.
 157          */
 158         u64                     fh_pre_change;
 159
 160         /* Post-op attributes saved in fh_unlock */
 161         struct kstat            fh_post_attr;   /* full attrs after operation */
 162         u64                     fh_post_change; /* nfsv4 change; see above */
 163 #endif /* CONFIG_NFSD_V3 */
 164
 165 } svc_fh;
 166
 167 enum nfsd_fsid {
 168         FSID_DEV = 0,
 169         FSID_NUM,
 170         FSID_MAJOR_MINOR,
 171         FSID_ENCODE_DEV,
 172         FSID_UUID4_INUM,
 173         FSID_UUID8,
 174         FSID_UUID16,
 175         FSID_UUID16_INUM,
 176 };
 177
 178 enum fsid_source {
 179         FSIDSOURCE_DEV,
 180         FSIDSOURCE_FSID,
 181         FSIDSOURCE_UUID,
 182 };
 183 extern enum fsid_source fsid_source(struct svc_fh *fhp);
 184
 185
 186 /* This might look a little large to "inline" but in all calls except
 187  * one, 'vers' is constant so moste of the function disappears.
 188  */
 189 static inline void mk_fsid(int vers, u32 *fsidv, dev_t dev, ino_t ino,
 190                            u32 fsid, unsigned char *uuid)
 191 {
 192         u32 *up;
 193         switch(vers) {
 194         case FSID_DEV:
 195                 fsidv[0] = htonl((MAJOR(dev)<<16) |
 196                                  MINOR(dev));
 197                 fsidv[1] = ino_t_to_u32(ino);
 198                 break;
 199         case FSID_NUM:
 200                 fsidv[0] = fsid;
 201                 break;
 202         case FSID_MAJOR_MINOR:
 203                 fsidv[0] = htonl(MAJOR(dev));
 204                 fsidv[1] = htonl(MINOR(dev));
 205                 fsidv[2] = ino_t_to_u32(ino);
 206                 break;
 207
 208         case FSID_ENCODE_DEV:
 209                 fsidv[0] = new_encode_dev(dev);
 210                 fsidv[1] = ino_t_to_u32(ino);
 211                 break;
 212
 213         case FSID_UUID4_INUM:
 214                 /* 4 byte fsid and inode number */
 215                 up = (u32*)uuid;
 216                 fsidv[0] = ino_t_to_u32(ino);
 217                 fsidv[1] = up[0] ^ up[1] ^ up[2] ^ up[3];
 218                 break;
 219
 220         case FSID_UUID8:
 221                 /* 8 byte fsid  */
 222                 up = (u32*)uuid;
 223                 fsidv[0] = up[0] ^ up[2];
 224                 fsidv[1] = up[1] ^ up[3];
 225                 break;
 226
 227         case FSID_UUID16:
 228                 /* 16 byte fsid - NFSv3+ only */
 229                 memcpy(fsidv, uuid, 16);
 230                 break;
 231
 232         case FSID_UUID16_INUM:
 233                 /* 8 byte inode and 16 byte fsid */
 234                 *(u64*)fsidv = (u64)ino;
 235                 memcpy(fsidv+2, uuid, 16);
 236                 break;
 237         default: BUG();
 238         }
 239 }
 240
 241 static inline int key_len(int type)
 242 {
 243         switch(type) {
 244         case FSID_DEV:          return 8;
 245         case FSID_NUM:          return 4;
 246         case FSID_MAJOR_MINOR:  return 12;
 247         case FSID_ENCODE_DEV:   return 8;
 248         case FSID_UUID4_INUM:   return 8;
 249         case FSID_UUID8:        return 8;
 250         case FSID_UUID16:       return 16;
 251         case FSID_UUID16_INUM:  return 24;
 252         default: return 0;
 253         }
 254 }
 255
 256 /*
 257  * Shorthand for dprintk()'s
 258  */
 259 extern char * SVCFH_fmt(struct svc_fh *fhp);
 260
 261 /*
 262  * Function prototypes
 263  */
 264 __be32  fh_verify(struct svc_rqst *, struct svc_fh *, int, int);
 265 __be32  fh_compose(struct svc_fh *, struct svc_export *, struct dentry *, struct svc_fh *);
 266 __be32  fh_update(struct svc_fh *);
 267 void    fh_put(struct svc_fh *);
 268
 269 static __inline__ struct svc_fh *
 270 fh_copy(struct svc_fh *dst, struct svc_fh *src)
 271 {
 272         WARN_ON(src->fh_dentry || src->fh_locked);
 273
 274         *dst = *src;
 275         return dst;
 276 }
 277
 278 static inline void
 279 fh_copy_shallow(struct knfsd_fh *dst, struct knfsd_fh *src)
 280 {
 281         dst->fh_size = src->fh_size;
 282         memcpy(&dst->fh_base, &src->fh_base, src->fh_size);
 283 }
 284
 285 static __inline__ struct svc_fh *
 286 fh_init(struct svc_fh *fhp, int maxsize)
 287 {
 288         memset(fhp, 0, sizeof(*fhp));
 289         fhp->fh_maxsize = maxsize;
 290         return fhp;
 291 }
 292
 293 #ifdef CONFIG_NFSD_V3
 294 /*
 295  * Fill in the pre_op attr for the wcc data
 296  */
 297 static inline void
 298 fill_pre_wcc(struct svc_fh *fhp)
 299 {
 300         struct inode    *inode;
 301
 302         inode = fhp->fh_dentry->d_inode;
 303         if (!fhp->fh_pre_saved) {
 304                 fhp->fh_pre_mtime = inode->i_mtime;
 305                 fhp->fh_pre_ctime = inode->i_ctime;
 306                 fhp->fh_pre_size  = inode->i_size;
 307                 fhp->fh_pre_change = inode->i_version;
 308                 fhp->fh_pre_saved = 1;
 309         }
 310 }
 311
 312 extern void fill_post_wcc(struct svc_fh *);
 313 #else
 314 #define fill_pre_wcc(ignored)
 315 #define fill_post_wcc(notused)
 316 #endif /* CONFIG_NFSD_V3 */
 317
 318
 319 /*
 320  * Lock a file handle/inode
 321  * NOTE: both fh_lock and fh_unlock are done "by hand" in
 322  * vfs.c:nfsd_rename as it needs to grab 2 i_mutex's at once
 323  * so, any changes here should be reflected there.
 324  */
 325
 326 static inline void
 327 fh_lock_nested(struct svc_fh *fhp, unsigned int subclass)
 328 {
 329         struct dentry   *dentry = fhp->fh_dentry;
 330         struct inode    *inode;
 331
 332         dfprintk(FILEOP, "nfsd: fh_lock(%s) locked = %d\n",
 333                         SVCFH_fmt(fhp), fhp->fh_locked);
 334
 335         BUG_ON(!dentry);
 336
 337         if (fhp->fh_locked) {
 338                 printk(KERN_WARNING "fh_lock: %s/%s already locked!\n",
 339                         dentry->d_parent->d_name.name, dentry->d_name.name);
 340                 return;
 341         }
 342
 343         inode = dentry->d_inode;
 344         mutex_lock_nested(&inode->i_mutex, subclass);
 345         fill_pre_wcc(fhp);
 346         fhp->fh_locked = 1;
 347 }
 348
 349 static inline void
 350 fh_lock(struct svc_fh *fhp)
 351 {
 352         fh_lock_nested(fhp, I_MUTEX_NORMAL);
 353 }
 354
 355 /*
 356  * Unlock a file handle/inode
 357  */
 358 static inline void
 359 fh_unlock(struct svc_fh *fhp)
 360 {
 361         BUG_ON(!fhp->fh_dentry);
 362
 363         if (fhp->fh_locked) {
 364                 fill_post_wcc(fhp);
 365                 mutex_unlock(&fhp->fh_dentry->d_inode->i_mutex);
 366                 fhp->fh_locked = 0;
 367         }
 368 }
 369 #endif /* __KERNEL__ */
 370
 371
 372 #endif /* _LINUX_NFSD_FH_H */