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  *
  72  * The fileid_type identified how the file within the filesystem is encoded.
  73  * This is (will be) passed to, and set by, the underlying filesystem if it supports
  74  * filehandle operations.  The filesystem must not use the value '0' or '0xff' and may
  75  * only use the values 1 and 2 as defined below:
  76  *  Current values:
  77  *    0   - The root, or export point, of the filesystem.  fb_fileid is 0 bytes.
  78  *    1   - 32bit inode number, 32 bit generation number.
  79  *    2   - 32bit inode number, 32 bit generation number, 32 bit parent directory inode number.
  80  *
  81  */
  82 struct nfs_fhbase_new {
  83         __u8            fb_version;     /* == 1, even => nfs_fhbase_old */
  84         __u8            fb_auth_type;
  85         __u8            fb_fsid_type;
  86         __u8            fb_fileid_type;
  87         __u32           fb_auth[1];
  88 /*      __u32           fb_fsid[0]; floating */
  89 /*      __u32           fb_fileid[0]; floating */
  90 };
  91
  92 struct knfsd_fh {
  93         unsigned int    fh_size;        /* significant for NFSv3.
  94                                          * Points to the current size while building
  95                                          * a new file handle
  96                                          */
  97         union {
  98                 struct nfs_fhbase_old   fh_old;
  99                 __u32                   fh_pad[NFS4_FHSIZE/4];
 100                 struct nfs_fhbase_new   fh_new;
 101         } fh_base;
 102 };
 103
 104 #define ofh_dcookie             fh_base.fh_old.fb_dcookie
 105 #define ofh_ino                 fh_base.fh_old.fb_ino
 106 #define ofh_dirino              fh_base.fh_old.fb_dirino
 107 #define ofh_dev                 fh_base.fh_old.fb_dev
 108 #define ofh_xdev                fh_base.fh_old.fb_xdev
 109 #define ofh_xino                fh_base.fh_old.fb_xino
 110 #define ofh_generation          fh_base.fh_old.fb_generation
 111
 112 #define fh_version              fh_base.fh_new.fb_version
 113 #define fh_fsid_type            fh_base.fh_new.fb_fsid_type
 114 #define fh_auth_type            fh_base.fh_new.fb_auth_type
 115 #define fh_fileid_type          fh_base.fh_new.fb_fileid_type
 116 #define fh_auth                 fh_base.fh_new.fb_auth
 117 #define fh_fsid                 fh_base.fh_new.fb_auth
 118
 119 #ifdef __KERNEL__
 120
 121 static inline __u32 ino_t_to_u32(ino_t ino)
 122 {
 123         return (__u32) ino;
 124 }
 125
 126 static inline ino_t u32_to_ino_t(__u32 uino)
 127 {
 128         return (ino_t) uino;
 129 }
 130
 131 /*
 132  * This is the internal representation of an NFS handle used in knfsd.
 133  * pre_mtime/post_version will be used to support wcc_attr's in NFSv3.
 134  */
 135 typedef struct svc_fh {
 136         struct knfsd_fh         fh_handle;      /* FH data */
 137         struct dentry *         fh_dentry;      /* validated dentry */
 138         struct svc_export *     fh_export;      /* export pointer */
 139         int                     fh_maxsize;     /* max size for fh_handle */
 140
 141         unsigned char           fh_locked;      /* inode locked by us */
 142
 143 #ifdef CONFIG_NFSD_V3
 144         unsigned char           fh_post_saved;  /* post-op attrs saved */
 145         unsigned char           fh_pre_saved;   /* pre-op attrs saved */
 146
 147         /* Pre-op attributes saved during fh_lock */
 148         __u64                   fh_pre_size;    /* size before operation */
 149         struct timespec         fh_pre_mtime;   /* mtime before oper */
 150         struct timespec         fh_pre_ctime;   /* ctime before oper */
 151
 152         /* Post-op attributes saved in fh_unlock */
 153         struct kstat            fh_post_attr;   /* full attrs after operation */
 154 #endif /* CONFIG_NFSD_V3 */
 155
 156 } svc_fh;
 157
 158 enum nfsd_fsid {
 159         FSID_DEV = 0,
 160         FSID_NUM,
 161         FSID_MAJOR_MINOR,
 162         FSID_ENCODE_DEV,
 163         FSID_UUID4_INUM,
 164         FSID_UUID8,
 165         FSID_UUID16,
 166         FSID_UUID16_INUM,
 167 };
 168
 169 enum fsid_source {
 170         FSIDSOURCE_DEV,
 171         FSIDSOURCE_FSID,
 172         FSIDSOURCE_UUID,
 173 };
 174 extern enum fsid_source fsid_source(struct svc_fh *fhp);
 175
 176
 177 /* This might look a little large to "inline" but in all calls except
 178  * one, 'vers' is constant so moste of the function disappears.
 179  */
 180 static inline void mk_fsid(int vers, u32 *fsidv, dev_t dev, ino_t ino,
 181                            u32 fsid, unsigned char *uuid)
 182 {
 183         u32 *up;
 184         switch(vers) {
 185         case FSID_DEV:
 186                 fsidv[0] = htonl((MAJOR(dev)<<16) |
 187                                  MINOR(dev));
 188                 fsidv[1] = ino_t_to_u32(ino);
 189                 break;
 190         case FSID_NUM:
 191                 fsidv[0] = fsid;
 192                 break;
 193         case FSID_MAJOR_MINOR:
 194                 fsidv[0] = htonl(MAJOR(dev));
 195                 fsidv[1] = htonl(MINOR(dev));
 196                 fsidv[2] = ino_t_to_u32(ino);
 197                 break;
 198
 199         case FSID_ENCODE_DEV:
 200                 fsidv[0] = new_encode_dev(dev);
 201                 fsidv[1] = ino_t_to_u32(ino);
 202                 break;
 203
 204         case FSID_UUID4_INUM:
 205                 /* 4 byte fsid and inode number */
 206                 up = (u32*)uuid;
 207                 fsidv[0] = ino_t_to_u32(ino);
 208                 fsidv[1] = up[0] ^ up[1] ^ up[2] ^ up[3];
 209                 break;
 210
 211         case FSID_UUID8:
 212                 /* 8 byte fsid  */
 213                 up = (u32*)uuid;
 214                 fsidv[0] = up[0] ^ up[2];
 215                 fsidv[1] = up[1] ^ up[3];
 216                 break;
 217
 218         case FSID_UUID16:
 219                 /* 16 byte fsid - NFSv3+ only */
 220                 memcpy(fsidv, uuid, 16);
 221                 break;
 222
 223         case FSID_UUID16_INUM:
 224                 /* 8 byte inode and 16 byte fsid */
 225                 *(u64*)fsidv = (u64)ino;
 226                 memcpy(fsidv+2, uuid, 16);
 227                 break;
 228         default: BUG();
 229         }
 230 }
 231
 232 static inline int key_len(int type)
 233 {
 234         switch(type) {
 235         case FSID_DEV:          return 8;
 236         case FSID_NUM:          return 4;
 237         case FSID_MAJOR_MINOR:  return 12;
 238         case FSID_ENCODE_DEV:   return 8;
 239         case FSID_UUID4_INUM:   return 8;
 240         case FSID_UUID8:        return 8;
 241         case FSID_UUID16:       return 16;
 242         case FSID_UUID16_INUM:  return 24;
 243         default: return 0;
 244         }
 245 }
 246
 247 /*
 248  * Shorthand for dprintk()'s
 249  */
 250 extern char * SVCFH_fmt(struct svc_fh *fhp);
 251
 252 /*
 253  * Function prototypes
 254  */
 255 __be32  fh_verify(struct svc_rqst *, struct svc_fh *, int, int);
 256 __be32  fh_compose(struct svc_fh *, struct svc_export *, struct dentry *, struct svc_fh *);
 257 __be32  fh_update(struct svc_fh *);
 258 void    fh_put(struct svc_fh *);
 259
 260 static __inline__ struct svc_fh *
 261 fh_copy(struct svc_fh *dst, struct svc_fh *src)
 262 {
 263         WARN_ON(src->fh_dentry || src->fh_locked);
 264
 265         *dst = *src;
 266         return dst;
 267 }
 268
 269 static __inline__ struct svc_fh *
 270 fh_init(struct svc_fh *fhp, int maxsize)
 271 {
 272         memset(fhp, 0, sizeof(*fhp));
 273         fhp->fh_maxsize = maxsize;
 274         return fhp;
 275 }
 276
 277 #ifdef CONFIG_NFSD_V3
 278 /*
 279  * Fill in the pre_op attr for the wcc data
 280  */
 281 static inline void
 282 fill_pre_wcc(struct svc_fh *fhp)
 283 {
 284         struct inode    *inode;
 285
 286         inode = fhp->fh_dentry->d_inode;
 287         if (!fhp->fh_pre_saved) {
 288                 fhp->fh_pre_mtime = inode->i_mtime;
 289                 fhp->fh_pre_ctime = inode->i_ctime;
 290                 fhp->fh_pre_size  = inode->i_size;
 291                 fhp->fh_pre_saved = 1;
 292         }
 293 }
 294
 295 extern void fill_post_wcc(struct svc_fh *);
 296 #else
 297 #define fill_pre_wcc(ignored)
 298 #define fill_post_wcc(notused)
 299 #endif /* CONFIG_NFSD_V3 */
 300
 301
 302 /*
 303  * Lock a file handle/inode
 304  * NOTE: both fh_lock and fh_unlock are done "by hand" in
 305  * vfs.c:nfsd_rename as it needs to grab 2 i_mutex's at once
 306  * so, any changes here should be reflected there.
 307  */
 308
 309 static inline void
 310 fh_lock_nested(struct svc_fh *fhp, unsigned int subclass)
 311 {
 312         struct dentry   *dentry = fhp->fh_dentry;
 313         struct inode    *inode;
 314
 315         dfprintk(FILEOP, "nfsd: fh_lock(%s) locked = %d\n",
 316                         SVCFH_fmt(fhp), fhp->fh_locked);
 317
 318         BUG_ON(!dentry);
 319
 320         if (fhp->fh_locked) {
 321                 printk(KERN_WARNING "fh_lock: %s/%s already locked!\n",
 322                         dentry->d_parent->d_name.name, dentry->d_name.name);
 323                 return;
 324         }
 325
 326         inode = dentry->d_inode;
 327         mutex_lock_nested(&inode->i_mutex, subclass);
 328         fill_pre_wcc(fhp);
 329         fhp->fh_locked = 1;
 330 }
 331
 332 static inline void
 333 fh_lock(struct svc_fh *fhp)
 334 {
 335         fh_lock_nested(fhp, I_MUTEX_NORMAL);
 336 }
 337
 338 /*
 339  * Unlock a file handle/inode
 340  */
 341 static inline void
 342 fh_unlock(struct svc_fh *fhp)
 343 {
 344         BUG_ON(!fhp->fh_dentry);
 345
 346         if (fhp->fh_locked) {
 347                 fill_post_wcc(fhp);
 348                 mutex_unlock(&fhp->fh_dentry->d_inode->i_mutex);
 349                 fhp->fh_locked = 0;
 350         }
 351 }
 352 #endif /* __KERNEL__ */
 353
 354
 355 #endif /* _LINUX_NFSD_FH_H */