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