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         umode_t                 fh_post_mode;   /* i_mode */
 154         nlink_t                 fh_post_nlink;  /* i_nlink */
 155         uid_t                   fh_post_uid;    /* i_uid */
 156         gid_t                   fh_post_gid;    /* i_gid */
 157         __u64                   fh_post_size;   /* i_size */
 158         unsigned long           fh_post_blocks; /* i_blocks */
 159         unsigned long           fh_post_blksize;/* i_blksize */
 160         __be32                  fh_post_rdev[2];/* i_rdev */
 161         struct timespec         fh_post_atime;  /* i_atime */
 162         struct timespec         fh_post_mtime;  /* i_mtime */
 163         struct timespec         fh_post_ctime;  /* i_ctime */
 164 #endif /* CONFIG_NFSD_V3 */
 165
 166 } svc_fh;
 167
 168 static inline void mk_fsid_v0(u32 *fsidv, dev_t dev, ino_t ino)
 169 {
 170         fsidv[0] = htonl((MAJOR(dev)<<16) |
 171                         MINOR(dev));
 172         fsidv[1] = ino_t_to_u32(ino);
 173 }
 174
 175 static inline void mk_fsid_v1(u32 *fsidv, u32 fsid)
 176 {
 177         fsidv[0] = fsid;
 178 }
 179
 180 static inline void mk_fsid_v2(u32 *fsidv, dev_t dev, ino_t ino)
 181 {
 182         fsidv[0] = htonl(MAJOR(dev));
 183         fsidv[1] = htonl(MINOR(dev));
 184         fsidv[2] = ino_t_to_u32(ino);
 185 }
 186
 187 static inline void mk_fsid_v3(u32 *fsidv, dev_t dev, ino_t ino)
 188 {
 189         fsidv[0] = new_encode_dev(dev);
 190         fsidv[1] = ino_t_to_u32(ino);
 191 }
 192
 193 static inline int key_len(int type)
 194 {
 195         switch(type) {
 196         case 0: return 8;
 197         case 1: return 4;
 198         case 2: return 12;
 199         case 3: return 8;
 200         default: return 0;
 201         }
 202 }
 203
 204 /*
 205  * Shorthand for dprintk()'s
 206  */
 207 extern char * SVCFH_fmt(struct svc_fh *fhp);
 208
 209 /*
 210  * Function prototypes
 211  */
 212 __be32  fh_verify(struct svc_rqst *, struct svc_fh *, int, int);
 213 __be32  fh_compose(struct svc_fh *, struct svc_export *, struct dentry *, struct svc_fh *);
 214 __be32  fh_update(struct svc_fh *);
 215 void    fh_put(struct svc_fh *);
 216
 217 static __inline__ struct svc_fh *
 218 fh_copy(struct svc_fh *dst, struct svc_fh *src)
 219 {
 220         WARN_ON(src->fh_dentry || src->fh_locked);
 221
 222         *dst = *src;
 223         return dst;
 224 }
 225
 226 static __inline__ struct svc_fh *
 227 fh_init(struct svc_fh *fhp, int maxsize)
 228 {
 229         memset(fhp, 0, sizeof(*fhp));
 230         fhp->fh_maxsize = maxsize;
 231         return fhp;
 232 }
 233
 234 #ifdef CONFIG_NFSD_V3
 235 /*
 236  * Fill in the pre_op attr for the wcc data
 237  */
 238 static inline void
 239 fill_pre_wcc(struct svc_fh *fhp)
 240 {
 241         struct inode    *inode;
 242
 243         inode = fhp->fh_dentry->d_inode;
 244         if (!fhp->fh_pre_saved) {
 245                 fhp->fh_pre_mtime = inode->i_mtime;
 246                 fhp->fh_pre_ctime = inode->i_ctime;
 247                         fhp->fh_pre_size  = inode->i_size;
 248                         fhp->fh_pre_saved = 1;
 249         }
 250 }
 251
 252 /*
 253  * Fill in the post_op attr for the wcc data
 254  */
 255 static inline void
 256 fill_post_wcc(struct svc_fh *fhp)
 257 {
 258         struct inode    *inode = fhp->fh_dentry->d_inode;
 259
 260         if (fhp->fh_post_saved)
 261                 printk("nfsd: inode locked twice during operation.\n");
 262
 263         fhp->fh_post_mode       = inode->i_mode;
 264         fhp->fh_post_nlink      = inode->i_nlink;
 265         fhp->fh_post_uid        = inode->i_uid;
 266         fhp->fh_post_gid        = inode->i_gid;
 267         fhp->fh_post_size       = inode->i_size;
 268         fhp->fh_post_blksize    = BLOCK_SIZE;
 269         fhp->fh_post_blocks     = inode->i_blocks;
 270         fhp->fh_post_rdev[0]    = htonl((u32)imajor(inode));
 271         fhp->fh_post_rdev[1]    = htonl((u32)iminor(inode));
 272         fhp->fh_post_atime      = inode->i_atime;
 273         fhp->fh_post_mtime      = inode->i_mtime;
 274         fhp->fh_post_ctime      = inode->i_ctime;
 275         fhp->fh_post_saved      = 1;
 276 }
 277 #else
 278 #define fill_pre_wcc(ignored)
 279 #define fill_post_wcc(notused)
 280 #endif /* CONFIG_NFSD_V3 */
 281
 282
 283 /*
 284  * Lock a file handle/inode
 285  * NOTE: both fh_lock and fh_unlock are done "by hand" in
 286  * vfs.c:nfsd_rename as it needs to grab 2 i_mutex's at once
 287  * so, any changes here should be reflected there.
 288  */
 289
 290 static inline void
 291 fh_lock_nested(struct svc_fh *fhp, unsigned int subclass)
 292 {
 293         struct dentry   *dentry = fhp->fh_dentry;
 294         struct inode    *inode;
 295
 296         dfprintk(FILEOP, "nfsd: fh_lock(%s) locked = %d\n",
 297                         SVCFH_fmt(fhp), fhp->fh_locked);
 298
 299         BUG_ON(!dentry);
 300
 301         if (fhp->fh_locked) {
 302                 printk(KERN_WARNING "fh_lock: %s/%s already locked!\n",
 303                         dentry->d_parent->d_name.name, dentry->d_name.name);
 304                 return;
 305         }
 306
 307         inode = dentry->d_inode;
 308         mutex_lock_nested(&inode->i_mutex, subclass);
 309         fill_pre_wcc(fhp);
 310         fhp->fh_locked = 1;
 311 }
 312
 313 static inline void
 314 fh_lock(struct svc_fh *fhp)
 315 {
 316         fh_lock_nested(fhp, I_MUTEX_NORMAL);
 317 }
 318
 319 /*
 320  * Unlock a file handle/inode
 321  */
 322 static inline void
 323 fh_unlock(struct svc_fh *fhp)
 324 {
 325         BUG_ON(!fhp->fh_dentry);
 326
 327         if (fhp->fh_locked) {
 328                 fill_post_wcc(fhp);
 329                 mutex_unlock(&fhp->fh_dentry->d_inode->i_mutex);
 330                 fhp->fh_locked = 0;
 331         }
 332 }
 333 #endif /* __KERNEL__ */
 334
 335
 336 #endif /* _LINUX_NFSD_FH_H */