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/config.h>
  20 # include <linux/types.h>
  21 # include <linux/string.h>
  22 # include <linux/fs.h>
  23 #endif
  24 #include <linux/nfsd/const.h>
  25 #include <linux/nfsd/debug.h>
  26
  27 /*
  28  * This is the old "dentry style" Linux NFSv2 file handle.
  29  *
  30  * The xino and xdev fields are currently used to transport the
  31  * ino/dev of the exported inode.
  32  */
  33 struct nfs_fhbase_old {
  34         __u32           fb_dcookie;     /* dentry cookie - always 0xfeebbaca */
  35         __u32           fb_ino;         /* our inode number */
  36         __u32           fb_dirino;      /* dir inode number, 0 for directories */
  37         __u32           fb_dev;         /* our device */
  38         __u32           fb_xdev;
  39         __u32           fb_xino;
  40         __u32           fb_generation;
  41 };
  42
  43 /*
  44  * This is the new flexible, extensible style NFSv2/v3 file handle.
  45  * by Neil Brown <neilb@cse.unsw.edu.au> - March 2000
  46  *
  47  * The file handle is seens as a list of 4byte words.
  48  * The first word contains a version number (1) and four descriptor bytes
  49  * that tell how the remaining 3 variable length fields should be handled.
  50  * These three bytes are auth_type, fsid_type and fileid_type.
  51  *
  52  * All 4byte values are in host-byte-order.
  53  *
  54  * The auth_type field specifies how the filehandle can be authenticated
  55  * This might allow a file to be confirmed to be in a writable part of a
  56  * filetree without checking the path from it upto the root.
  57  * Current values:
  58  *     0  - No authentication.  fb_auth is 0 bytes long
  59  * Possible future values:
  60  *     1  - 4 bytes taken from MD5 hash of the remainer of the file handle
  61  *          prefixed by a secret and with the important export flags.
  62  *
  63  * The fsid_type identifies how the filesystem (or export point) is
  64  *    encoded.
  65  *  Current values:
  66  *     0  - 4 byte device id (ms-2-bytes major, ls-2-bytes minor), 4byte inode number
  67  *        NOTE: we cannot use the kdev_t device id value, because kdev_t.h
  68  *              says we mustn't.  We must break it up and reassemble.
  69  *     1  - 4 byte user specified identifier
  70  *     2  - 4 byte major, 4 byte minor, 4 byte inode number - DEPRECATED
  71  *     3  - 4 byte device id, encoded for user-space, 4 byte inode number
  72  *
  73  * The fileid_type identified how the file within the filesystem is encoded.
  74  * This is (will be) passed to, and set by, the underlying filesystem if it supports
  75  * filehandle operations.  The filesystem must not use the value '0' or '0xff' and may
  76  * only use the values 1 and 2 as defined below:
  77  *  Current values:
  78  *    0   - The root, or export point, of the filesystem.  fb_fileid is 0 bytes.
  79  *    1   - 32bit inode number, 32 bit generation number.
  80  *    2   - 32bit inode number, 32 bit generation number, 32 bit parent directory inode number.
  81  *
  82  */
  83 struct nfs_fhbase_new {
  84         __u8            fb_version;     /* == 1, even => nfs_fhbase_old */
  85         __u8            fb_auth_type;
  86         __u8            fb_fsid_type;
  87         __u8            fb_fileid_type;
  88         __u32           fb_auth[1];
  89 /*      __u32           fb_fsid[0]; floating */
  90 /*      __u32           fb_fileid[0]; floating */
  91 };
  92
  93 struct knfsd_fh {
  94         unsigned int    fh_size;        /* significant for NFSv3.
  95                                          * Points to the current size while building
  96                                          * a new file handle
  97                                          */
  98         union {
  99                 struct nfs_fhbase_old   fh_old;
 100                 __u32                   fh_pad[NFS4_FHSIZE/4];
 101                 struct nfs_fhbase_new   fh_new;
 102         } fh_base;
 103 };
 104
 105 #define ofh_dcookie             fh_base.fh_old.fb_dcookie
 106 #define ofh_ino                 fh_base.fh_old.fb_ino
 107 #define ofh_dirino              fh_base.fh_old.fb_dirino
 108 #define ofh_dev                 fh_base.fh_old.fb_dev
 109 #define ofh_xdev                fh_base.fh_old.fb_xdev
 110 #define ofh_xino                fh_base.fh_old.fb_xino
 111 #define ofh_generation          fh_base.fh_old.fb_generation
 112
 113 #define fh_version              fh_base.fh_new.fb_version
 114 #define fh_fsid_type            fh_base.fh_new.fb_fsid_type
 115 #define fh_auth_type            fh_base.fh_new.fb_auth_type
 116 #define fh_fileid_type          fh_base.fh_new.fb_fileid_type
 117 #define fh_auth                 fh_base.fh_new.fb_auth
 118 #define fh_fsid                 fh_base.fh_new.fb_auth
 119
 120 #ifdef __KERNEL__
 121
 122 static inline __u32 ino_t_to_u32(ino_t ino)
 123 {
 124         return (__u32) ino;
 125 }
 126
 127 static inline ino_t u32_to_ino_t(__u32 uino)
 128 {
 129         return (ino_t) uino;
 130 }
 131
 132 /*
 133  * This is the internal representation of an NFS handle used in knfsd.
 134  * pre_mtime/post_version will be used to support wcc_attr's in NFSv3.
 135  */
 136 typedef struct svc_fh {
 137         struct knfsd_fh         fh_handle;      /* FH data */
 138         struct dentry *         fh_dentry;      /* validated dentry */
 139         struct svc_export *     fh_export;      /* export pointer */
 140         int                     fh_maxsize;     /* max size for fh_handle */
 141
 142         unsigned char           fh_locked;      /* inode locked by us */
 143
 144 #ifdef CONFIG_NFSD_V3
 145         unsigned char           fh_post_saved;  /* post-op attrs saved */
 146         unsigned char           fh_pre_saved;   /* pre-op attrs saved */
 147
 148         /* Pre-op attributes saved during fh_lock */
 149         __u64                   fh_pre_size;    /* size before operation */
 150         struct timespec         fh_pre_mtime;   /* mtime before oper */
 151         struct timespec         fh_pre_ctime;   /* ctime before oper */
 152
 153         /* Post-op attributes saved in fh_unlock */
 154         umode_t                 fh_post_mode;   /* i_mode */
 155         nlink_t                 fh_post_nlink;  /* i_nlink */
 156         uid_t                   fh_post_uid;    /* i_uid */
 157         gid_t                   fh_post_gid;    /* i_gid */
 158         __u64                   fh_post_size;   /* i_size */
 159         unsigned long           fh_post_blocks; /* i_blocks */
 160         unsigned long           fh_post_blksize;/* i_blksize */
 161         __u32                   fh_post_rdev[2];/* i_rdev */
 162         struct timespec         fh_post_atime;  /* i_atime */
 163         struct timespec         fh_post_mtime;  /* i_mtime */
 164         struct timespec         fh_post_ctime;  /* i_ctime */
 165 #endif /* CONFIG_NFSD_V3 */
 166
 167 } svc_fh;
 168
 169 static inline void mk_fsid_v0(u32 *fsidv, dev_t dev, ino_t ino)
 170 {
 171         fsidv[0] = htonl((MAJOR(dev)<<16) |
 172                         MINOR(dev));
 173         fsidv[1] = ino_t_to_u32(ino);
 174 }
 175
 176 static inline void mk_fsid_v1(u32 *fsidv, u32 fsid)
 177 {
 178         fsidv[0] = fsid;
 179 }
 180
 181 static inline void mk_fsid_v2(u32 *fsidv, dev_t dev, ino_t ino)
 182 {
 183         fsidv[0] = htonl(MAJOR(dev));
 184         fsidv[1] = htonl(MINOR(dev));
 185         fsidv[2] = ino_t_to_u32(ino);
 186 }
 187
 188 static inline void mk_fsid_v3(u32 *fsidv, dev_t dev, ino_t ino)
 189 {
 190         fsidv[0] = new_encode_dev(dev);
 191         fsidv[1] = ino_t_to_u32(ino);
 192 }
 193
 194 static inline int key_len(int type)
 195 {
 196         switch(type) {
 197         case 0: return 8;
 198         case 1: return 4;
 199         case 2: return 12;
 200         case 3: return 8;
 201         default: return 0;
 202         }
 203 }
 204
 205 /*
 206  * Shorthand for dprintk()'s
 207  */
 208 extern char * SVCFH_fmt(struct svc_fh *fhp);
 209
 210 /*
 211  * Function prototypes
 212  */
 213 u32     fh_verify(struct svc_rqst *, struct svc_fh *, int, int);
 214 int     fh_compose(struct svc_fh *, struct svc_export *, struct dentry *, struct svc_fh *);
 215 int     fh_update(struct svc_fh *);
 216 void    fh_put(struct svc_fh *);
 217
 218 static __inline__ struct svc_fh *
 219 fh_copy(struct svc_fh *dst, struct svc_fh *src)
 220 {
 221         if (src->fh_dentry || src->fh_locked) {
 222                 struct dentry *dentry = src->fh_dentry;
 223                 printk(KERN_ERR "fh_copy: copying %s/%s, already verified!\n",
 224                         dentry->d_parent->d_name.name, dentry->d_name.name);
 225         }
 226
 227         *dst = *src;
 228         return dst;
 229 }
 230
 231 static __inline__ struct svc_fh *
 232 fh_init(struct svc_fh *fhp, int maxsize)
 233 {
 234         memset(fhp, 0, sizeof(*fhp));
 235         fhp->fh_maxsize = maxsize;
 236         return fhp;
 237 }
 238
 239 #ifdef CONFIG_NFSD_V3
 240 /*
 241  * Fill in the pre_op attr for the wcc data
 242  */
 243 static inline void
 244 fill_pre_wcc(struct svc_fh *fhp)
 245 {
 246         struct inode    *inode;
 247
 248         inode = fhp->fh_dentry->d_inode;
 249         if (!fhp->fh_pre_saved) {
 250                 fhp->fh_pre_mtime = inode->i_mtime;
 251                 fhp->fh_pre_ctime = inode->i_ctime;
 252                         fhp->fh_pre_size  = inode->i_size;
 253                         fhp->fh_pre_saved = 1;
 254         }
 255 }
 256
 257 /*
 258  * Fill in the post_op attr for the wcc data
 259  */
 260 static inline void
 261 fill_post_wcc(struct svc_fh *fhp)
 262 {
 263         struct inode    *inode = fhp->fh_dentry->d_inode;
 264
 265         if (fhp->fh_post_saved)
 266                 printk("nfsd: inode locked twice during operation.\n");
 267
 268         fhp->fh_post_mode       = inode->i_mode;
 269         fhp->fh_post_nlink      = inode->i_nlink;
 270         fhp->fh_post_uid        = inode->i_uid;
 271         fhp->fh_post_gid        = inode->i_gid;
 272         fhp->fh_post_size       = inode->i_size;
 273         if (inode->i_blksize) {
 274                 fhp->fh_post_blksize    = inode->i_blksize;
 275                 fhp->fh_post_blocks     = inode->i_blocks;
 276         } else {
 277                 fhp->fh_post_blksize    = BLOCK_SIZE;
 278                 /* how much do we care for accuracy with MinixFS? */
 279                 fhp->fh_post_blocks     = (inode->i_size+511) >> 9;
 280         }
 281         fhp->fh_post_rdev[0]    = htonl((u32)imajor(inode));
 282         fhp->fh_post_rdev[1]    = htonl((u32)iminor(inode));
 283         fhp->fh_post_atime      = inode->i_atime;
 284         fhp->fh_post_mtime      = inode->i_mtime;
 285         fhp->fh_post_ctime      = inode->i_ctime;
 286         fhp->fh_post_saved      = 1;
 287 }
 288 #else
 289 #define fill_pre_wcc(ignored)
 290 #define fill_post_wcc(notused)
 291 #endif /* CONFIG_NFSD_V3 */
 292
 293
 294 /*
 295  * Lock a file handle/inode
 296  * NOTE: both fh_lock and fh_unlock are done "by hand" in
 297  * vfs.c:nfsd_rename as it needs to grab 2 i_sem's at once
 298  * so, any changes here should be reflected there.
 299  */
 300 static inline void
 301 fh_lock(struct svc_fh *fhp)
 302 {
 303         struct dentry   *dentry = fhp->fh_dentry;
 304         struct inode    *inode;
 305
 306         dfprintk(FILEOP, "nfsd: fh_lock(%s) locked = %d\n",
 307                         SVCFH_fmt(fhp), fhp->fh_locked);
 308
 309         if (!fhp->fh_dentry) {
 310                 printk(KERN_ERR "fh_lock: fh not verified!\n");
 311                 return;
 312         }
 313         if (fhp->fh_locked) {
 314                 printk(KERN_WARNING "fh_lock: %s/%s already locked!\n",
 315                         dentry->d_parent->d_name.name, dentry->d_name.name);
 316                 return;
 317         }
 318
 319         inode = dentry->d_inode;
 320         down(&inode->i_sem);
 321         fill_pre_wcc(fhp);
 322         fhp->fh_locked = 1;
 323 }
 324
 325 /*
 326  * Unlock a file handle/inode
 327  */
 328 static inline void
 329 fh_unlock(struct svc_fh *fhp)
 330 {
 331         if (!fhp->fh_dentry)
 332                 printk(KERN_ERR "fh_unlock: fh not verified!\n");
 333
 334         if (fhp->fh_locked) {
 335                 fill_post_wcc(fhp);
 336                 up(&fhp->fh_dentry->d_inode->i_sem);
 337                 fhp->fh_locked = 0;
 338         }
 339 }
 340 #endif /* __KERNEL__ */
 341
 342
 343 #endif /* _LINUX_NFSD_FH_H */