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         int                     fh_flags;       /* FH flags */
  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 timespec64       fh_pre_mtime;   /* mtime before oper */
  46         struct timespec64       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 #define NFSD4_FH_FOREIGN (1<<0)
  60 #define SET_FH_FLAG(c, f) ((c)->fh_flags |= (f))
  61 #define HAS_FH_FLAG(c, f) ((c)->fh_flags & (f))
  62
  63 enum nfsd_fsid {
  64         FSID_DEV = 0,
  65         FSID_NUM,
  66         FSID_MAJOR_MINOR,
  67         FSID_ENCODE_DEV,
  68         FSID_UUID4_INUM,
  69         FSID_UUID8,
  70         FSID_UUID16,
  71         FSID_UUID16_INUM,
  72 };
  73
  74 enum fsid_source {
  75         FSIDSOURCE_DEV,
  76         FSIDSOURCE_FSID,
  77         FSIDSOURCE_UUID,
  78 };
  79 extern enum fsid_source fsid_source(struct svc_fh *fhp);
  80
  81
  82 /*
  83  * This might look a little large to "inline" but in all calls except
  84  * one, 'vers' is constant so moste of the function disappears.
  85  *
  86  * In some cases the values are considered to be host endian and in
  87  * others, net endian. fsidv is always considered to be u32 as the
  88  * callers don't know which it will be. So we must use __force to keep
  89  * sparse from complaining. Since these values are opaque to the
  90  * client, that shouldn't be a problem.
  91  */
  92 static inline void mk_fsid(int vers, u32 *fsidv, dev_t dev, ino_t ino,
  93                            u32 fsid, unsigned char *uuid)
  94 {
  95         u32 *up;
  96         switch(vers) {
  97         case FSID_DEV:
  98                 fsidv[0] = (__force __u32)htonl((MAJOR(dev)<<16) |
  99                                  MINOR(dev));
 100                 fsidv[1] = ino_t_to_u32(ino);
 101                 break;
 102         case FSID_NUM:
 103                 fsidv[0] = fsid;
 104                 break;
 105         case FSID_MAJOR_MINOR:
 106                 fsidv[0] = (__force __u32)htonl(MAJOR(dev));
 107                 fsidv[1] = (__force __u32)htonl(MINOR(dev));
 108                 fsidv[2] = ino_t_to_u32(ino);
 109                 break;
 110
 111         case FSID_ENCODE_DEV:
 112                 fsidv[0] = new_encode_dev(dev);
 113                 fsidv[1] = ino_t_to_u32(ino);
 114                 break;
 115
 116         case FSID_UUID4_INUM:
 117                 /* 4 byte fsid and inode number */
 118                 up = (u32*)uuid;
 119                 fsidv[0] = ino_t_to_u32(ino);
 120                 fsidv[1] = up[0] ^ up[1] ^ up[2] ^ up[3];
 121                 break;
 122
 123         case FSID_UUID8:
 124                 /* 8 byte fsid  */
 125                 up = (u32*)uuid;
 126                 fsidv[0] = up[0] ^ up[2];
 127                 fsidv[1] = up[1] ^ up[3];
 128                 break;
 129
 130         case FSID_UUID16:
 131                 /* 16 byte fsid - NFSv3+ only */
 132                 memcpy(fsidv, uuid, 16);
 133                 break;
 134
 135         case FSID_UUID16_INUM:
 136                 /* 8 byte inode and 16 byte fsid */
 137                 *(u64*)fsidv = (u64)ino;
 138                 memcpy(fsidv+2, uuid, 16);
 139                 break;
 140         default: BUG();
 141         }
 142 }
 143
 144 static inline int key_len(int type)
 145 {
 146         switch(type) {
 147         case FSID_DEV:          return 8;
 148         case FSID_NUM:          return 4;
 149         case FSID_MAJOR_MINOR:  return 12;
 150         case FSID_ENCODE_DEV:   return 8;
 151         case FSID_UUID4_INUM:   return 8;
 152         case FSID_UUID8:        return 8;
 153         case FSID_UUID16:       return 16;
 154         case FSID_UUID16_INUM:  return 24;
 155         default: return 0;
 156         }
 157 }
 158
 159 /*
 160  * Shorthand for dprintk()'s
 161  */
 162 extern char * SVCFH_fmt(struct svc_fh *fhp);
 163
 164 /*
 165  * Function prototypes
 166  */
 167 __be32  fh_verify(struct svc_rqst *, struct svc_fh *, umode_t, int);
 168 __be32  fh_compose(struct svc_fh *, struct svc_export *, struct dentry *, struct svc_fh *);
 169 __be32  fh_update(struct svc_fh *);
 170 void    fh_put(struct svc_fh *);
 171
 172 static __inline__ struct svc_fh *
 173 fh_copy(struct svc_fh *dst, struct svc_fh *src)
 174 {
 175         WARN_ON(src->fh_dentry || src->fh_locked);
 176
 177         *dst = *src;
 178         return dst;
 179 }
 180
 181 static inline void
 182 fh_copy_shallow(struct knfsd_fh *dst, struct knfsd_fh *src)
 183 {
 184         dst->fh_size = src->fh_size;
 185         memcpy(&dst->fh_base, &src->fh_base, src->fh_size);
 186 }
 187
 188 static __inline__ struct svc_fh *
 189 fh_init(struct svc_fh *fhp, int maxsize)
 190 {
 191         memset(fhp, 0, sizeof(*fhp));
 192         fhp->fh_maxsize = maxsize;
 193         return fhp;
 194 }
 195
 196 static inline bool fh_match(struct knfsd_fh *fh1, struct knfsd_fh *fh2)
 197 {
 198         if (fh1->fh_size != fh2->fh_size)
 199                 return false;
 200         if (memcmp(fh1->fh_base.fh_pad, fh2->fh_base.fh_pad, fh1->fh_size) != 0)
 201                 return false;
 202         return true;
 203 }
 204
 205 static inline bool fh_fsid_match(struct knfsd_fh *fh1, struct knfsd_fh *fh2)
 206 {
 207         if (fh1->fh_fsid_type != fh2->fh_fsid_type)
 208                 return false;
 209         if (memcmp(fh1->fh_fsid, fh2->fh_fsid, key_len(fh1->fh_fsid_type)) != 0)
 210                 return false;
 211         return true;
 212 }
 213
 214 #ifdef CONFIG_CRC32
 215 /**
 216  * knfsd_fh_hash - calculate the crc32 hash for the filehandle
 217  * @fh - pointer to filehandle
 218  *
 219  * returns a crc32 hash for the filehandle that is compatible with
 220  * the one displayed by "wireshark".
 221  */
 222
 223 static inline u32
 224 knfsd_fh_hash(struct knfsd_fh *fh)
 225 {
 226         return ~crc32_le(0xFFFFFFFF, (unsigned char *)&fh->fh_base, fh->fh_size);
 227 }
 228 #else
 229 static inline u32
 230 knfsd_fh_hash(struct knfsd_fh *fh)
 231 {
 232         return 0;
 233 }
 234 #endif
 235
 236 #ifdef CONFIG_NFSD_V3
 237 /*
 238  * The wcc data stored in current_fh should be cleared
 239  * between compound ops.
 240  */
 241 static inline void
 242 fh_clear_wcc(struct svc_fh *fhp)
 243 {
 244         fhp->fh_post_saved = false;
 245         fhp->fh_pre_saved = false;
 246 }
 247
 248 /*
 249  * We could use i_version alone as the change attribute.  However,
 250  * i_version can go backwards after a reboot.  On its own that doesn't
 251  * necessarily cause a problem, but if i_version goes backwards and then
 252  * is incremented again it could reuse a value that was previously used
 253  * before boot, and a client who queried the two values might
 254  * incorrectly assume nothing changed.
 255  *
 256  * By using both ctime and the i_version counter we guarantee that as
 257  * long as time doesn't go backwards we never reuse an old value.
 258  */
 259 static inline u64 nfsd4_change_attribute(struct kstat *stat,
 260                                          struct inode *inode)
 261 {
 262         u64 chattr;
 263
 264         chattr =  stat->ctime.tv_sec;
 265         chattr <<= 30;
 266         chattr += stat->ctime.tv_nsec;
 267         chattr += inode_query_iversion(inode);
 268         return chattr;
 269 }
 270
 271 extern void fill_pre_wcc(struct svc_fh *fhp);
 272 extern void fill_post_wcc(struct svc_fh *fhp);
 273 #else
 274 #define fh_clear_wcc(ignored)
 275 #define fill_pre_wcc(ignored)
 276 #define fill_post_wcc(notused)
 277 #endif /* CONFIG_NFSD_V3 */
 278
 279
 280 /*
 281  * Lock a file handle/inode
 282  * NOTE: both fh_lock and fh_unlock are done "by hand" in
 283  * vfs.c:nfsd_rename as it needs to grab 2 i_mutex's at once
 284  * so, any changes here should be reflected there.
 285  */
 286
 287 static inline void
 288 fh_lock_nested(struct svc_fh *fhp, unsigned int subclass)
 289 {
 290         struct dentry   *dentry = fhp->fh_dentry;
 291         struct inode    *inode;
 292
 293         BUG_ON(!dentry);
 294
 295         if (fhp->fh_locked) {
 296                 printk(KERN_WARNING "fh_lock: %pd2 already locked!\n",
 297                         dentry);
 298                 return;
 299         }
 300
 301         inode = d_inode(dentry);
 302         inode_lock_nested(inode, subclass);
 303         fill_pre_wcc(fhp);
 304         fhp->fh_locked = true;
 305 }
 306
 307 static inline void
 308 fh_lock(struct svc_fh *fhp)
 309 {
 310         fh_lock_nested(fhp, I_MUTEX_NORMAL);
 311 }
 312
 313 /*
 314  * Unlock a file handle/inode
 315  */
 316 static inline void
 317 fh_unlock(struct svc_fh *fhp)
 318 {
 319         if (fhp->fh_locked) {
 320                 fill_post_wcc(fhp);
 321                 inode_unlock(d_inode(fhp->fh_dentry));
 322                 fhp->fh_locked = false;
 323         }
 324 }
 325
 326 #endif /* _LINUX_NFSD_NFSFH_H */