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