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