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 #include <linux/exportfs.h>
  16
  17 static inline __u32 ino_t_to_u32(ino_t ino)
  18 {
  19         return (__u32) ino;
  20 }
  21
  22 static inline ino_t u32_to_ino_t(__u32 uino)
  23 {
  24         return (ino_t) uino;
  25 }
  26
  27 /*
  28  * This is the internal representation of an NFS handle used in knfsd.
  29  * pre_mtime/post_version will be used to support wcc_attr's in NFSv3.
  30  */
  31 typedef struct svc_fh {
  32         struct knfsd_fh         fh_handle;      /* FH data */
  33         int                     fh_maxsize;     /* max size for fh_handle */
  34         struct dentry *         fh_dentry;      /* validated dentry */
  35         struct svc_export *     fh_export;      /* export pointer */
  36
  37         bool                    fh_locked;      /* inode locked by us */
  38         bool                    fh_want_write;  /* remount protection taken */
  39         bool                    fh_no_wcc;      /* no wcc data needed */
  40         bool                    fh_no_atomic_attr;
  41                                                 /*
  42                                                  * wcc data is not atomic with
  43                                                  * operation
  44                                                  */
  45         int                     fh_flags;       /* FH flags */
  46 #ifdef CONFIG_NFSD_V3
  47         bool                    fh_post_saved;  /* post-op attrs saved */
  48         bool                    fh_pre_saved;   /* pre-op attrs saved */
  49
  50         /* Pre-op attributes saved during fh_lock */
  51         __u64                   fh_pre_size;    /* size before operation */
  52         struct timespec64       fh_pre_mtime;   /* mtime before oper */
  53         struct timespec64       fh_pre_ctime;   /* ctime before oper */
  54         /*
  55          * pre-op nfsv4 change attr: note must check IS_I_VERSION(inode)
  56          *  to find out if it is valid.
  57          */
  58         u64                     fh_pre_change;
  59
  60         /* Post-op attributes saved in fh_unlock */
  61         struct kstat            fh_post_attr;   /* full attrs after operation */
  62         u64                     fh_post_change; /* nfsv4 change; see above */
  63 #endif /* CONFIG_NFSD_V3 */
  64 } svc_fh;
  65 #define NFSD4_FH_FOREIGN (1<<0)
  66 #define SET_FH_FLAG(c, f) ((c)->fh_flags |= (f))
  67 #define HAS_FH_FLAG(c, f) ((c)->fh_flags & (f))
  68
  69 enum nfsd_fsid {
  70         FSID_DEV = 0,
  71         FSID_NUM,
  72         FSID_MAJOR_MINOR,
  73         FSID_ENCODE_DEV,
  74         FSID_UUID4_INUM,
  75         FSID_UUID8,
  76         FSID_UUID16,
  77         FSID_UUID16_INUM,
  78 };
  79
  80 enum fsid_source {
  81         FSIDSOURCE_DEV,
  82         FSIDSOURCE_FSID,
  83         FSIDSOURCE_UUID,
  84 };
  85 extern enum fsid_source fsid_source(const struct svc_fh *fhp);
  86
  87
  88 /*
  89  * This might look a little large to "inline" but in all calls except
  90  * one, 'vers' is constant so moste of the function disappears.
  91  *
  92  * In some cases the values are considered to be host endian and in
  93  * others, net endian. fsidv is always considered to be u32 as the
  94  * callers don't know which it will be. So we must use __force to keep
  95  * sparse from complaining. Since these values are opaque to the
  96  * client, that shouldn't be a problem.
  97  */
  98 static inline void mk_fsid(int vers, u32 *fsidv, dev_t dev, ino_t ino,
  99                            u32 fsid, unsigned char *uuid)
 100 {
 101         u32 *up;
 102         switch(vers) {
 103         case FSID_DEV:
 104                 fsidv[0] = (__force __u32)htonl((MAJOR(dev)<<16) |
 105                                  MINOR(dev));
 106                 fsidv[1] = ino_t_to_u32(ino);
 107                 break;
 108         case FSID_NUM:
 109                 fsidv[0] = fsid;
 110                 break;
 111         case FSID_MAJOR_MINOR:
 112                 fsidv[0] = (__force __u32)htonl(MAJOR(dev));
 113                 fsidv[1] = (__force __u32)htonl(MINOR(dev));
 114                 fsidv[2] = ino_t_to_u32(ino);
 115                 break;
 116
 117         case FSID_ENCODE_DEV:
 118                 fsidv[0] = new_encode_dev(dev);
 119                 fsidv[1] = ino_t_to_u32(ino);
 120                 break;
 121
 122         case FSID_UUID4_INUM:
 123                 /* 4 byte fsid and inode number */
 124                 up = (u32*)uuid;
 125                 fsidv[0] = ino_t_to_u32(ino);
 126                 fsidv[1] = up[0] ^ up[1] ^ up[2] ^ up[3];
 127                 break;
 128
 129         case FSID_UUID8:
 130                 /* 8 byte fsid  */
 131                 up = (u32*)uuid;
 132                 fsidv[0] = up[0] ^ up[2];
 133                 fsidv[1] = up[1] ^ up[3];
 134                 break;
 135
 136         case FSID_UUID16:
 137                 /* 16 byte fsid - NFSv3+ only */
 138                 memcpy(fsidv, uuid, 16);
 139                 break;
 140
 141         case FSID_UUID16_INUM:
 142                 /* 8 byte inode and 16 byte fsid */
 143                 *(u64*)fsidv = (u64)ino;
 144                 memcpy(fsidv+2, uuid, 16);
 145                 break;
 146         default: BUG();
 147         }
 148 }
 149
 150 static inline int key_len(int type)
 151 {
 152         switch(type) {
 153         case FSID_DEV:          return 8;
 154         case FSID_NUM:          return 4;
 155         case FSID_MAJOR_MINOR:  return 12;
 156         case FSID_ENCODE_DEV:   return 8;
 157         case FSID_UUID4_INUM:   return 8;
 158         case FSID_UUID8:        return 8;
 159         case FSID_UUID16:       return 16;
 160         case FSID_UUID16_INUM:  return 24;
 161         default: return 0;
 162         }
 163 }
 164
 165 /*
 166  * Shorthand for dprintk()'s
 167  */
 168 extern char * SVCFH_fmt(struct svc_fh *fhp);
 169
 170 /*
 171  * Function prototypes
 172  */
 173 __be32  fh_verify(struct svc_rqst *, struct svc_fh *, umode_t, int);
 174 __be32  fh_compose(struct svc_fh *, struct svc_export *, struct dentry *, struct svc_fh *);
 175 __be32  fh_update(struct svc_fh *);
 176 void    fh_put(struct svc_fh *);
 177
 178 static __inline__ struct svc_fh *
 179 fh_copy(struct svc_fh *dst, struct svc_fh *src)
 180 {
 181         WARN_ON(src->fh_dentry || src->fh_locked);
 182
 183         *dst = *src;
 184         return dst;
 185 }
 186
 187 static inline void
 188 fh_copy_shallow(struct knfsd_fh *dst, struct knfsd_fh *src)
 189 {
 190         dst->fh_size = src->fh_size;
 191         memcpy(&dst->fh_base, &src->fh_base, src->fh_size);
 192 }
 193
 194 static __inline__ struct svc_fh *
 195 fh_init(struct svc_fh *fhp, int maxsize)
 196 {
 197         memset(fhp, 0, sizeof(*fhp));
 198         fhp->fh_maxsize = maxsize;
 199         return fhp;
 200 }
 201
 202 static inline bool fh_match(struct knfsd_fh *fh1, struct knfsd_fh *fh2)
 203 {
 204         if (fh1->fh_size != fh2->fh_size)
 205                 return false;
 206         if (memcmp(fh1->fh_base.fh_pad, fh2->fh_base.fh_pad, fh1->fh_size) != 0)
 207                 return false;
 208         return true;
 209 }
 210
 211 static inline bool fh_fsid_match(struct knfsd_fh *fh1, struct knfsd_fh *fh2)
 212 {
 213         if (fh1->fh_fsid_type != fh2->fh_fsid_type)
 214                 return false;
 215         if (memcmp(fh1->fh_fsid, fh2->fh_fsid, key_len(fh1->fh_fsid_type)) != 0)
 216                 return false;
 217         return true;
 218 }
 219
 220 #ifdef CONFIG_CRC32
 221 /**
 222  * knfsd_fh_hash - calculate the crc32 hash for the filehandle
 223  * @fh - pointer to filehandle
 224  *
 225  * returns a crc32 hash for the filehandle that is compatible with
 226  * the one displayed by "wireshark".
 227  */
 228
 229 static inline u32
 230 knfsd_fh_hash(struct knfsd_fh *fh)
 231 {
 232         return ~crc32_le(0xFFFFFFFF, (unsigned char *)&fh->fh_base, fh->fh_size);
 233 }
 234 #else
 235 static inline u32
 236 knfsd_fh_hash(struct knfsd_fh *fh)
 237 {
 238         return 0;
 239 }
 240 #endif
 241
 242 #ifdef CONFIG_NFSD_V3
 243 /*
 244  * The wcc data stored in current_fh should be cleared
 245  * between compound ops.
 246  */
 247 static inline void
 248 fh_clear_wcc(struct svc_fh *fhp)
 249 {
 250         fhp->fh_post_saved = false;
 251         fhp->fh_pre_saved = false;
 252 }
 253
 254 /*
 255  * We could use i_version alone as the change attribute.  However,
 256  * i_version can go backwards after a reboot.  On its own that doesn't
 257  * necessarily cause a problem, but if i_version goes backwards and then
 258  * is incremented again it could reuse a value that was previously used
 259  * before boot, and a client who queried the two values might
 260  * incorrectly assume nothing changed.
 261  *
 262  * By using both ctime and the i_version counter we guarantee that as
 263  * long as time doesn't go backwards we never reuse an old value.
 264  */
 265 static inline u64 nfsd4_change_attribute(struct kstat *stat,
 266                                          struct inode *inode)
 267 {
 268         if (inode->i_sb->s_export_op->fetch_iversion)
 269                 return inode->i_sb->s_export_op->fetch_iversion(inode);
 270         else if (IS_I_VERSION(inode)) {
 271                 u64 chattr;
 272
 273                 chattr =  stat->ctime.tv_sec;
 274                 chattr <<= 30;
 275                 chattr += stat->ctime.tv_nsec;
 276                 chattr += inode_query_iversion(inode);
 277                 return chattr;
 278         } else
 279                 return time_to_chattr(&stat->ctime);
 280 }
 281
 282 extern void fill_pre_wcc(struct svc_fh *fhp);
 283 extern void fill_post_wcc(struct svc_fh *fhp);
 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 */