fs/nfsd/nfsfh.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3  * Copyright (C) 1995, 1996, 1997 Olaf Kirch <okir@monad.swb.de>
   4  *
   5  * This file describes the layout of the file handles as passed
   6  * over the wire.
   7  */
   8 #ifndef _LINUX_NFSD_NFSFH_H
   9 #define _LINUX_NFSD_NFSFH_H
  10
  11 #include <linux/crc32.h>
  12 #include <linux/sunrpc/svc.h>
  13 #include <uapi/linux/nfsd/nfsfh.h>
  14 #include <linux/iversion.h>
  15
  16 static inline __u32 ino_t_to_u32(ino_t ino)
  17 {
  18         return (__u32) ino;
  19 }
  20
  21 static inline ino_t u32_to_ino_t(__u32 uino)
  22 {
  23         return (ino_t) uino;
  24 }
  25
  26 /*
  27  * This is the internal representation of an NFS handle used in knfsd.
  28  * pre_mtime/post_version will be used to support wcc_attr's in NFSv3.
  29  */
  30 typedef struct svc_fh {
  31         struct knfsd_fh         fh_handle;      /* FH data */
  32         int                     fh_maxsize;     /* max size for fh_handle */
  33         struct dentry *         fh_dentry;      /* validated dentry */
  34         struct svc_export *     fh_export;      /* export pointer */
  35
  36         bool                    fh_locked;      /* inode locked by us */
  37         bool                    fh_want_write;  /* remount protection taken */
  38
  39 #ifdef CONFIG_NFSD_V3
  40         bool                    fh_post_saved;  /* post-op attrs saved */
  41         bool                    fh_pre_saved;   /* pre-op attrs saved */
  42
  43         /* Pre-op attributes saved during fh_lock */
  44         __u64                   fh_pre_size;    /* size before operation */
  45         struct timespec         fh_pre_mtime;   /* mtime before oper */
  46         struct timespec         fh_pre_ctime;   /* ctime before oper */
  47         /*
  48          * pre-op nfsv4 change attr: note must check IS_I_VERSION(inode)
  49          *  to find out if it is valid.
  50          */
  51         u64                     fh_pre_change;
  52
  53         /* Post-op attributes saved in fh_unlock */
  54         struct kstat            fh_post_attr;   /* full attrs after operation */
  55         u64                     fh_post_change; /* nfsv4 change; see above */
  56 #endif /* CONFIG_NFSD_V3 */
  57
  58 } svc_fh;
  59
  60 enum nfsd_fsid {
  61         FSID_DEV = 0,
  62         FSID_NUM,
  63         FSID_MAJOR_MINOR,
  64         FSID_ENCODE_DEV,
  65         FSID_UUID4_INUM,
  66         FSID_UUID8,
  67         FSID_UUID16,
  68         FSID_UUID16_INUM,
  69 };
  70
  71 enum fsid_source {
  72         FSIDSOURCE_DEV,
  73         FSIDSOURCE_FSID,
  74         FSIDSOURCE_UUID,
  75 };
  76 extern enum fsid_source fsid_source(struct svc_fh *fhp);
  77
  78
  79 /*
  80  * This might look a little large to "inline" but in all calls except
  81  * one, 'vers' is constant so moste of the function disappears.
  82  *
  83  * In some cases the values are considered to be host endian and in
  84  * others, net endian. fsidv is always considered to be u32 as the
  85  * callers don't know which it will be. So we must use __force to keep
  86  * sparse from complaining. Since these values are opaque to the
  87  * client, that shouldn't be a problem.
  88  */
  89 static inline void mk_fsid(int vers, u32 *fsidv, dev_t dev, ino_t ino,
  90                            u32 fsid, unsigned char *uuid)
  91 {
  92         u32 *up;
  93         switch(vers) {
  94         case FSID_DEV:
  95                 fsidv[0] = (__force __u32)htonl((MAJOR(dev)<<16) |
  96                                  MINOR(dev));
  97                 fsidv[1] = ino_t_to_u32(ino);
  98                 break;
  99         case FSID_NUM:
 100                 fsidv[0] = fsid;
 101                 break;
 102         case FSID_MAJOR_MINOR:
 103                 fsidv[0] = (__force __u32)htonl(MAJOR(dev));
 104                 fsidv[1] = (__force __u32)htonl(MINOR(dev));
 105                 fsidv[2] = ino_t_to_u32(ino);
 106                 break;
 107
 108         case FSID_ENCODE_DEV:
 109                 fsidv[0] = new_encode_dev(dev);
 110                 fsidv[1] = ino_t_to_u32(ino);
 111                 break;
 112
 113         case FSID_UUID4_INUM:
 114                 /* 4 byte fsid and inode number */
 115                 up = (u32*)uuid;
 116                 fsidv[0] = ino_t_to_u32(ino);
 117                 fsidv[1] = up[0] ^ up[1] ^ up[2] ^ up[3];
 118                 break;
 119
 120         case FSID_UUID8:
 121                 /* 8 byte fsid  */
 122                 up = (u32*)uuid;
 123                 fsidv[0] = up[0] ^ up[2];
 124                 fsidv[1] = up[1] ^ up[3];
 125                 break;
 126
 127         case FSID_UUID16:
 128                 /* 16 byte fsid - NFSv3+ only */
 129                 memcpy(fsidv, uuid, 16);
 130                 break;
 131
 132         case FSID_UUID16_INUM:
 133                 /* 8 byte inode and 16 byte fsid */
 134                 *(u64*)fsidv = (u64)ino;
 135                 memcpy(fsidv+2, uuid, 16);
 136                 break;
 137         default: BUG();
 138         }
 139 }
 140
 141 static inline int key_len(int type)
 142 {
 143         switch(type) {
 144         case FSID_DEV:          return 8;
 145         case FSID_NUM:          return 4;
 146         case FSID_MAJOR_MINOR:  return 12;
 147         case FSID_ENCODE_DEV:   return 8;
 148         case FSID_UUID4_INUM:   return 8;
 149         case FSID_UUID8:        return 8;
 150         case FSID_UUID16:       return 16;
 151         case FSID_UUID16_INUM:  return 24;
 152         default: return 0;
 153         }
 154 }
 155
 156 /*
 157  * Shorthand for dprintk()'s
 158  */
 159 extern char * SVCFH_fmt(struct svc_fh *fhp);
 160
 161 /*
 162  * Function prototypes
 163  */
 164 __be32  fh_verify(struct svc_rqst *, struct svc_fh *, umode_t, int);
 165 __be32  fh_compose(struct svc_fh *, struct svc_export *, struct dentry *, struct svc_fh *);
 166 __be32  fh_update(struct svc_fh *);
 167 void    fh_put(struct svc_fh *);
 168
 169 static __inline__ struct svc_fh *
 170 fh_copy(struct svc_fh *dst, struct svc_fh *src)
 171 {
 172         WARN_ON(src->fh_dentry || src->fh_locked);
 173
 174         *dst = *src;
 175         return dst;
 176 }
 177
 178 static inline void
 179 fh_copy_shallow(struct knfsd_fh *dst, struct knfsd_fh *src)
 180 {
 181         dst->fh_size = src->fh_size;
 182         memcpy(&dst->fh_base, &src->fh_base, src->fh_size);
 183 }
 184
 185 static __inline__ struct svc_fh *
 186 fh_init(struct svc_fh *fhp, int maxsize)
 187 {
 188         memset(fhp, 0, sizeof(*fhp));
 189         fhp->fh_maxsize = maxsize;
 190         return fhp;
 191 }
 192
 193 static inline bool fh_match(struct knfsd_fh *fh1, struct knfsd_fh *fh2)
 194 {
 195         if (fh1->fh_size != fh2->fh_size)
 196                 return false;
 197         if (memcmp(fh1->fh_base.fh_pad, fh2->fh_base.fh_pad, fh1->fh_size) != 0)
 198                 return false;
 199         return true;
 200 }
 201
 202 static inline bool fh_fsid_match(struct knfsd_fh *fh1, struct knfsd_fh *fh2)
 203 {
 204         if (fh1->fh_fsid_type != fh2->fh_fsid_type)
 205                 return false;
 206         if (memcmp(fh1->fh_fsid, fh2->fh_fsid, key_len(fh1->fh_fsid_type)) != 0)
 207                 return false;
 208         return true;
 209 }
 210
 211 #ifdef CONFIG_CRC32
 212 /**
 213  * knfsd_fh_hash - calculate the crc32 hash for the filehandle
 214  * @fh - pointer to filehandle
 215  *
 216  * returns a crc32 hash for the filehandle that is compatible with
 217  * the one displayed by "wireshark".
 218  */
 219
 220 static inline u32
 221 knfsd_fh_hash(struct knfsd_fh *fh)
 222 {
 223         return ~crc32_le(0xFFFFFFFF, (unsigned char *)&fh->fh_base, fh->fh_size);
 224 }
 225 #else
 226 static inline u32
 227 knfsd_fh_hash(struct knfsd_fh *fh)
 228 {
 229         return 0;
 230 }
 231 #endif
 232
 233 #ifdef CONFIG_NFSD_V3
 234 /*
 235  * The wcc data stored in current_fh should be cleared
 236  * between compound ops.
 237  */
 238 static inline void
 239 fh_clear_wcc(struct svc_fh *fhp)
 240 {
 241         fhp->fh_post_saved = false;
 242         fhp->fh_pre_saved = false;
 243 }
 244
 245 /*
 246  * We could use i_version alone as the change attribute.  However,
 247  * i_version can go backwards after a reboot.  On its own that doesn't
 248  * necessarily cause a problem, but if i_version goes backwards and then
 249  * is incremented again it could reuse a value that was previously used
 250  * before boot, and a client who queried the two values might
 251  * incorrectly assume nothing changed.
 252  *
 253  * By using both ctime and the i_version counter we guarantee that as
 254  * long as time doesn't go backwards we never reuse an old value.
 255  */
 256 static inline u64 nfsd4_change_attribute(struct kstat *stat,
 257                                          struct inode *inode)
 258 {
 259         u64 chattr;
 260
 261         chattr =  stat->ctime.tv_sec;
 262         chattr <<= 30;
 263         chattr += stat->ctime.tv_nsec;
 264         chattr += inode_query_iversion(inode);
 265         return chattr;
 266 }
 267
 268 extern void fill_pre_wcc(struct svc_fh *fhp);
 269 extern void fill_post_wcc(struct svc_fh *fhp);
 270 #else
 271 #define fh_clear_wcc(ignored)
 272 #define fill_pre_wcc(ignored)
 273 #define fill_post_wcc(notused)
 274 #endif /* CONFIG_NFSD_V3 */
 275
 276
 277 /*
 278  * Lock a file handle/inode
 279  * NOTE: both fh_lock and fh_unlock are done "by hand" in
 280  * vfs.c:nfsd_rename as it needs to grab 2 i_mutex's at once
 281  * so, any changes here should be reflected there.
 282  */
 283
 284 static inline void
 285 fh_lock_nested(struct svc_fh *fhp, unsigned int subclass)
 286 {
 287         struct dentry   *dentry = fhp->fh_dentry;
 288         struct inode    *inode;
 289
 290         BUG_ON(!dentry);
 291
 292         if (fhp->fh_locked) {
 293                 printk(KERN_WARNING "fh_lock: %pd2 already locked!\n",
 294                         dentry);
 295                 return;
 296         }
 297
 298         inode = d_inode(dentry);
 299         inode_lock_nested(inode, subclass);
 300         fill_pre_wcc(fhp);
 301         fhp->fh_locked = true;
 302 }
 303
 304 static inline void
 305 fh_lock(struct svc_fh *fhp)
 306 {
 307         fh_lock_nested(fhp, I_MUTEX_NORMAL);
 308 }
 309
 310 /*
 311  * Unlock a file handle/inode
 312  */
 313 static inline void
 314 fh_unlock(struct svc_fh *fhp)
 315 {
 316         if (fhp->fh_locked) {
 317                 fill_post_wcc(fhp);
 318                 inode_unlock(d_inode(fhp->fh_dentry));
 319                 fhp->fh_locked = false;
 320         }
 321 }
 322
 323 #endif /* _LINUX_NFSD_NFSFH_H */