fs/nfsd/nfsfh.h

   1 /*
   2  * Copyright (C) 1995, 1996, 1997 Olaf Kirch <okir@monad.swb.de>
   3  *
   4  * This file describes the layout of the file handles as passed
   5  * over the wire.
   6  */
   7 #ifndef _LINUX_NFSD_NFSFH_H
   8 #define _LINUX_NFSD_NFSFH_H
   9
  10 #include <linux/crc32.h>
  11 #include <linux/sunrpc/svc.h>
  12 #include <uapi/linux/nfsd/nfsfh.h>
  13
  14 static inline __u32 ino_t_to_u32(ino_t ino)
  15 {
  16         return (__u32) ino;
  17 }
  18
  19 static inline ino_t u32_to_ino_t(__u32 uino)
  20 {
  21         return (ino_t) uino;
  22 }
  23
  24 /*
  25  * This is the internal representation of an NFS handle used in knfsd.
  26  * pre_mtime/post_version will be used to support wcc_attr's in NFSv3.
  27  */
  28 typedef struct svc_fh {
  29         struct knfsd_fh         fh_handle;      /* FH data */
  30         int                     fh_maxsize;     /* max size for fh_handle */
  31         struct dentry *         fh_dentry;      /* validated dentry */
  32         struct svc_export *     fh_export;      /* export pointer */
  33
  34         bool                    fh_locked;      /* inode locked by us */
  35         bool                    fh_want_write;  /* remount protection taken */
  36
  37 #ifdef CONFIG_NFSD_V3
  38         bool                    fh_post_saved;  /* post-op attrs saved */
  39         bool                    fh_pre_saved;   /* pre-op attrs saved */
  40
  41         /* Pre-op attributes saved during fh_lock */
  42         __u64                   fh_pre_size;    /* size before operation */
  43         struct timespec         fh_pre_mtime;   /* mtime before oper */
  44         struct timespec         fh_pre_ctime;   /* ctime before oper */
  45         /*
  46          * pre-op nfsv4 change attr: note must check IS_I_VERSION(inode)
  47          *  to find out if it is valid.
  48          */
  49         u64                     fh_pre_change;
  50
  51         /* Post-op attributes saved in fh_unlock */
  52         struct kstat            fh_post_attr;   /* full attrs after operation */
  53         u64                     fh_post_change; /* nfsv4 change; see above */
  54 #endif /* CONFIG_NFSD_V3 */
  55
  56 } svc_fh;
  57
  58 enum nfsd_fsid {
  59         FSID_DEV = 0,
  60         FSID_NUM,
  61         FSID_MAJOR_MINOR,
  62         FSID_ENCODE_DEV,
  63         FSID_UUID4_INUM,
  64         FSID_UUID8,
  65         FSID_UUID16,
  66         FSID_UUID16_INUM,
  67 };
  68
  69 enum fsid_source {
  70         FSIDSOURCE_DEV,
  71         FSIDSOURCE_FSID,
  72         FSIDSOURCE_UUID,
  73 };
  74 extern enum fsid_source fsid_source(struct svc_fh *fhp);
  75
  76
  77 /*
  78  * This might look a little large to "inline" but in all calls except
  79  * one, 'vers' is constant so moste of the function disappears.
  80  *
  81  * In some cases the values are considered to be host endian and in
  82  * others, net endian. fsidv is always considered to be u32 as the
  83  * callers don't know which it will be. So we must use __force to keep
  84  * sparse from complaining. Since these values are opaque to the
  85  * client, that shouldn't be a problem.
  86  */
  87 static inline void mk_fsid(int vers, u32 *fsidv, dev_t dev, ino_t ino,
  88                            u32 fsid, unsigned char *uuid)
  89 {
  90         u32 *up;
  91         switch(vers) {
  92         case FSID_DEV:
  93                 fsidv[0] = (__force __u32)htonl((MAJOR(dev)<<16) |
  94                                  MINOR(dev));
  95                 fsidv[1] = ino_t_to_u32(ino);
  96                 break;
  97         case FSID_NUM:
  98                 fsidv[0] = fsid;
  99                 break;
 100         case FSID_MAJOR_MINOR:
 101                 fsidv[0] = (__force __u32)htonl(MAJOR(dev));
 102                 fsidv[1] = (__force __u32)htonl(MINOR(dev));
 103                 fsidv[2] = ino_t_to_u32(ino);
 104                 break;
 105
 106         case FSID_ENCODE_DEV:
 107                 fsidv[0] = new_encode_dev(dev);
 108                 fsidv[1] = ino_t_to_u32(ino);
 109                 break;
 110
 111         case FSID_UUID4_INUM:
 112                 /* 4 byte fsid and inode number */
 113                 up = (u32*)uuid;
 114                 fsidv[0] = ino_t_to_u32(ino);
 115                 fsidv[1] = up[0] ^ up[1] ^ up[2] ^ up[3];
 116                 break;
 117
 118         case FSID_UUID8:
 119                 /* 8 byte fsid  */
 120                 up = (u32*)uuid;
 121                 fsidv[0] = up[0] ^ up[2];
 122                 fsidv[1] = up[1] ^ up[3];
 123                 break;
 124
 125         case FSID_UUID16:
 126                 /* 16 byte fsid - NFSv3+ only */
 127                 memcpy(fsidv, uuid, 16);
 128                 break;
 129
 130         case FSID_UUID16_INUM:
 131                 /* 8 byte inode and 16 byte fsid */
 132                 *(u64*)fsidv = (u64)ino;
 133                 memcpy(fsidv+2, uuid, 16);
 134                 break;
 135         default: BUG();
 136         }
 137 }
 138
 139 static inline int key_len(int type)
 140 {
 141         switch(type) {
 142         case FSID_DEV:          return 8;
 143         case FSID_NUM:          return 4;
 144         case FSID_MAJOR_MINOR:  return 12;
 145         case FSID_ENCODE_DEV:   return 8;
 146         case FSID_UUID4_INUM:   return 8;
 147         case FSID_UUID8:        return 8;
 148         case FSID_UUID16:       return 16;
 149         case FSID_UUID16_INUM:  return 24;
 150         default: return 0;
 151         }
 152 }
 153
 154 /*
 155  * Shorthand for dprintk()'s
 156  */
 157 extern char * SVCFH_fmt(struct svc_fh *fhp);
 158
 159 /*
 160  * Function prototypes
 161  */
 162 __be32  fh_verify(struct svc_rqst *, struct svc_fh *, umode_t, int);
 163 __be32  fh_compose(struct svc_fh *, struct svc_export *, struct dentry *, struct svc_fh *);
 164 __be32  fh_update(struct svc_fh *);
 165 void    fh_put(struct svc_fh *);
 166
 167 static __inline__ struct svc_fh *
 168 fh_copy(struct svc_fh *dst, struct svc_fh *src)
 169 {
 170         WARN_ON(src->fh_dentry || src->fh_locked);
 171
 172         *dst = *src;
 173         return dst;
 174 }
 175
 176 static inline void
 177 fh_copy_shallow(struct knfsd_fh *dst, struct knfsd_fh *src)
 178 {
 179         dst->fh_size = src->fh_size;
 180         memcpy(&dst->fh_base, &src->fh_base, src->fh_size);
 181 }
 182
 183 static __inline__ struct svc_fh *
 184 fh_init(struct svc_fh *fhp, int maxsize)
 185 {
 186         memset(fhp, 0, sizeof(*fhp));
 187         fhp->fh_maxsize = maxsize;
 188         return fhp;
 189 }
 190
 191 static inline bool fh_match(struct knfsd_fh *fh1, struct knfsd_fh *fh2)
 192 {
 193         if (fh1->fh_size != fh2->fh_size)
 194                 return false;
 195         if (memcmp(fh1->fh_base.fh_pad, fh2->fh_base.fh_pad, fh1->fh_size) != 0)
 196                 return false;
 197         return true;
 198 }
 199
 200 static inline bool fh_fsid_match(struct knfsd_fh *fh1, struct knfsd_fh *fh2)
 201 {
 202         if (fh1->fh_fsid_type != fh2->fh_fsid_type)
 203                 return false;
 204         if (memcmp(fh1->fh_fsid, fh2->fh_fsid, key_len(fh1->fh_fsid_type)) != 0)
 205                 return false;
 206         return true;
 207 }
 208
 209 #ifdef CONFIG_CRC32
 210 /**
 211  * knfsd_fh_hash - calculate the crc32 hash for the filehandle
 212  * @fh - pointer to filehandle
 213  *
 214  * returns a crc32 hash for the filehandle that is compatible with
 215  * the one displayed by "wireshark".
 216  */
 217
 218 static inline u32
 219 knfsd_fh_hash(struct knfsd_fh *fh)
 220 {
 221         return ~crc32_le(0xFFFFFFFF, (unsigned char *)&fh->fh_base, fh->fh_size);
 222 }
 223 #else
 224 static inline u32
 225 knfsd_fh_hash(struct knfsd_fh *fh)
 226 {
 227         return 0;
 228 }
 229 #endif
 230
 231 #ifdef CONFIG_NFSD_V3
 232 /*
 233  * The wcc data stored in current_fh should be cleared
 234  * between compound ops.
 235  */
 236 static inline void
 237 fh_clear_wcc(struct svc_fh *fhp)
 238 {
 239         fhp->fh_post_saved = false;
 240         fhp->fh_pre_saved = false;
 241 }
 242
 243 /*
 244  * We could use i_version alone as the change attribute.  However,
 245  * i_version can go backwards after a reboot.  On its own that doesn't
 246  * necessarily cause a problem, but if i_version goes backwards and then
 247  * is incremented again it could reuse a value that was previously used
 248  * before boot, and a client who queried the two values might
 249  * incorrectly assume nothing changed.
 250  *
 251  * By using both ctime and the i_version counter we guarantee that as
 252  * long as time doesn't go backwards we never reuse an old value.
 253  */
 254 static inline u64 nfsd4_change_attribute(struct inode *inode)
 255 {
 256         u64 chattr;
 257
 258         chattr =  inode->i_ctime.tv_sec;
 259         chattr <<= 30;
 260         chattr += inode->i_ctime.tv_nsec;
 261         chattr += inode->i_version;
 262         return chattr;
 263 }
 264
 265 /*
 266  * Fill in the pre_op attr for the wcc data
 267  */
 268 static inline void
 269 fill_pre_wcc(struct svc_fh *fhp)
 270 {
 271         struct inode    *inode;
 272
 273         inode = d_inode(fhp->fh_dentry);
 274         if (!fhp->fh_pre_saved) {
 275                 fhp->fh_pre_mtime = inode->i_mtime;
 276                 fhp->fh_pre_ctime = inode->i_ctime;
 277                 fhp->fh_pre_size  = inode->i_size;
 278                 fhp->fh_pre_change = nfsd4_change_attribute(inode);
 279                 fhp->fh_pre_saved = true;
 280         }
 281 }
 282
 283 extern void fill_post_wcc(struct svc_fh *);
 284 #else
 285 #define fh_clear_wcc(ignored)
 286 #define fill_pre_wcc(ignored)
 287 #define fill_post_wcc(notused)
 288 #endif /* CONFIG_NFSD_V3 */
 289
 290
 291 /*
 292  * Lock a file handle/inode
 293  * NOTE: both fh_lock and fh_unlock are done "by hand" in
 294  * vfs.c:nfsd_rename as it needs to grab 2 i_mutex's at once
 295  * so, any changes here should be reflected there.
 296  */
 297
 298 static inline void
 299 fh_lock_nested(struct svc_fh *fhp, unsigned int subclass)
 300 {
 301         struct dentry   *dentry = fhp->fh_dentry;
 302         struct inode    *inode;
 303
 304         BUG_ON(!dentry);
 305
 306         if (fhp->fh_locked) {
 307                 printk(KERN_WARNING "fh_lock: %pd2 already locked!\n",
 308                         dentry);
 309                 return;
 310         }
 311
 312         inode = d_inode(dentry);
 313         inode_lock_nested(inode, subclass);
 314         fill_pre_wcc(fhp);
 315         fhp->fh_locked = true;
 316 }
 317
 318 static inline void
 319 fh_lock(struct svc_fh *fhp)
 320 {
 321         fh_lock_nested(fhp, I_MUTEX_NORMAL);
 322 }
 323
 324 /*
 325  * Unlock a file handle/inode
 326  */
 327 static inline void
 328 fh_unlock(struct svc_fh *fhp)
 329 {
 330         if (fhp->fh_locked) {
 331                 fill_post_wcc(fhp);
 332                 inode_unlock(d_inode(fhp->fh_dentry));
 333                 fhp->fh_locked = false;
 334         }
 335 }
 336
 337 #endif /* _LINUX_NFSD_NFSFH_H */