fs/9p/vfs_inode.c

   1 /*
   2  *  linux/fs/9p/vfs_inode.c
   3  *
   4  * This file contains vfs inode ops for the 9P2000 protocol.
   5  *
   6  *  Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
   7  *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
   8  *
   9  *  This program is free software; you can redistribute it and/or modify
  10  *  it under the terms of the GNU General Public License version 2
  11  *  as published by the Free Software Foundation.
  12  *
  13  *  This program is distributed in the hope that it will be useful,
  14  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  *  GNU General Public License for more details.
  17  *
  18  *  You should have received a copy of the GNU General Public License
  19  *  along with this program; if not, write to:
  20  *  Free Software Foundation
  21  *  51 Franklin Street, Fifth Floor
  22  *  Boston, MA  02111-1301  USA
  23  *
  24  */
  25
  26 #include <linux/module.h>
  27 #include <linux/errno.h>
  28 #include <linux/fs.h>
  29 #include <linux/file.h>
  30 #include <linux/pagemap.h>
  31 #include <linux/stat.h>
  32 #include <linux/string.h>
  33 #include <linux/inet.h>
  34 #include <linux/namei.h>
  35 #include <linux/idr.h>
  36 #include <linux/sched.h>
  37 #include <linux/slab.h>
  38 #include <linux/xattr.h>
  39 #include <linux/posix_acl.h>
  40 #include <net/9p/9p.h>
  41 #include <net/9p/client.h>
  42
  43 #include "v9fs.h"
  44 #include "v9fs_vfs.h"
  45 #include "fid.h"
  46 #include "cache.h"
  47 #include "xattr.h"
  48 #include "acl.h"
  49
  50 static const struct inode_operations v9fs_dir_inode_operations;
  51 static const struct inode_operations v9fs_dir_inode_operations_dotu;
  52 static const struct inode_operations v9fs_file_inode_operations;
  53 static const struct inode_operations v9fs_symlink_inode_operations;
  54
  55 /**
  56  * unixmode2p9mode - convert unix mode bits to plan 9
  57  * @v9ses: v9fs session information
  58  * @mode: mode to convert
  59  *
  60  */
  61
  62 static int unixmode2p9mode(struct v9fs_session_info *v9ses, int mode)
  63 {
  64         int res;
  65         res = mode & 0777;
  66         if (S_ISDIR(mode))
  67                 res |= P9_DMDIR;
  68         if (v9fs_proto_dotu(v9ses)) {
  69                 if (S_ISLNK(mode))
  70                         res |= P9_DMSYMLINK;
  71                 if (v9ses->nodev == 0) {
  72                         if (S_ISSOCK(mode))
  73                                 res |= P9_DMSOCKET;
  74                         if (S_ISFIFO(mode))
  75                                 res |= P9_DMNAMEDPIPE;
  76                         if (S_ISBLK(mode))
  77                                 res |= P9_DMDEVICE;
  78                         if (S_ISCHR(mode))
  79                                 res |= P9_DMDEVICE;
  80                 }
  81
  82                 if ((mode & S_ISUID) == S_ISUID)
  83                         res |= P9_DMSETUID;
  84                 if ((mode & S_ISGID) == S_ISGID)
  85                         res |= P9_DMSETGID;
  86                 if ((mode & S_ISVTX) == S_ISVTX)
  87                         res |= P9_DMSETVTX;
  88                 if ((mode & P9_DMLINK))
  89                         res |= P9_DMLINK;
  90         }
  91
  92         return res;
  93 }
  94
  95 /**
  96  * p9mode2unixmode- convert plan9 mode bits to unix mode bits
  97  * @v9ses: v9fs session information
  98  * @stat: p9_wstat from which mode need to be derived
  99  * @rdev: major number, minor number in case of device files.
 100  *
 101  */
 102 static int p9mode2unixmode(struct v9fs_session_info *v9ses,
 103                            struct p9_wstat *stat, dev_t *rdev)
 104 {
 105         int res;
 106         int mode = stat->mode;
 107
 108         res = mode & S_IALLUGO;
 109         *rdev = 0;
 110
 111         if ((mode & P9_DMDIR) == P9_DMDIR)
 112                 res |= S_IFDIR;
 113         else if ((mode & P9_DMSYMLINK) && (v9fs_proto_dotu(v9ses)))
 114                 res |= S_IFLNK;
 115         else if ((mode & P9_DMSOCKET) && (v9fs_proto_dotu(v9ses))
 116                  && (v9ses->nodev == 0))
 117                 res |= S_IFSOCK;
 118         else if ((mode & P9_DMNAMEDPIPE) && (v9fs_proto_dotu(v9ses))
 119                  && (v9ses->nodev == 0))
 120                 res |= S_IFIFO;
 121         else if ((mode & P9_DMDEVICE) && (v9fs_proto_dotu(v9ses))
 122                  && (v9ses->nodev == 0)) {
 123                 char type = 0, ext[32];
 124                 int major = -1, minor = -1;
 125
 126                 strncpy(ext, stat->extension, sizeof(ext));
 127                 sscanf(ext, "%c %u %u", &type, &major, &minor);
 128                 switch (type) {
 129                 case 'c':
 130                         res |= S_IFCHR;
 131                         break;
 132                 case 'b':
 133                         res |= S_IFBLK;
 134                         break;
 135                 default:
 136                         P9_DPRINTK(P9_DEBUG_ERROR,
 137                                 "Unknown special type %c %s\n", type,
 138                                 stat->extension);
 139                 };
 140                 *rdev = MKDEV(major, minor);
 141         } else
 142                 res |= S_IFREG;
 143
 144         if (v9fs_proto_dotu(v9ses)) {
 145                 if ((mode & P9_DMSETUID) == P9_DMSETUID)
 146                         res |= S_ISUID;
 147
 148                 if ((mode & P9_DMSETGID) == P9_DMSETGID)
 149                         res |= S_ISGID;
 150
 151                 if ((mode & P9_DMSETVTX) == P9_DMSETVTX)
 152                         res |= S_ISVTX;
 153         }
 154         return res;
 155 }
 156
 157 /**
 158  * v9fs_uflags2omode- convert posix open flags to plan 9 mode bits
 159  * @uflags: flags to convert
 160  * @extended: if .u extensions are active
 161  */
 162
 163 int v9fs_uflags2omode(int uflags, int extended)
 164 {
 165         int ret;
 166
 167         ret = 0;
 168         switch (uflags&3) {
 169         default:
 170         case O_RDONLY:
 171                 ret = P9_OREAD;
 172                 break;
 173
 174         case O_WRONLY:
 175                 ret = P9_OWRITE;
 176                 break;
 177
 178         case O_RDWR:
 179                 ret = P9_ORDWR;
 180                 break;
 181         }
 182
 183         if (uflags & O_TRUNC)
 184                 ret |= P9_OTRUNC;
 185
 186         if (extended) {
 187                 if (uflags & O_EXCL)
 188                         ret |= P9_OEXCL;
 189
 190                 if (uflags & O_APPEND)
 191                         ret |= P9_OAPPEND;
 192         }
 193
 194         return ret;
 195 }
 196
 197 /**
 198  * v9fs_blank_wstat - helper function to setup a 9P stat structure
 199  * @wstat: structure to initialize
 200  *
 201  */
 202
 203 void
 204 v9fs_blank_wstat(struct p9_wstat *wstat)
 205 {
 206         wstat->type = ~0;
 207         wstat->dev = ~0;
 208         wstat->qid.type = ~0;
 209         wstat->qid.version = ~0;
 210         *((long long *)&wstat->qid.path) = ~0;
 211         wstat->mode = ~0;
 212         wstat->atime = ~0;
 213         wstat->mtime = ~0;
 214         wstat->length = ~0;
 215         wstat->name = NULL;
 216         wstat->uid = NULL;
 217         wstat->gid = NULL;
 218         wstat->muid = NULL;
 219         wstat->n_uid = ~0;
 220         wstat->n_gid = ~0;
 221         wstat->n_muid = ~0;
 222         wstat->extension = NULL;
 223 }
 224
 225 /**
 226  * v9fs_alloc_inode - helper function to allocate an inode
 227  *
 228  */
 229 struct inode *v9fs_alloc_inode(struct super_block *sb)
 230 {
 231         struct v9fs_inode *v9inode;
 232         v9inode = (struct v9fs_inode *)kmem_cache_alloc(v9fs_inode_cache,
 233                                                         GFP_KERNEL);
 234         if (!v9inode)
 235                 return NULL;
 236 #ifdef CONFIG_9P_FSCACHE
 237         v9inode->fscache = NULL;
 238         spin_lock_init(&v9inode->fscache_lock);
 239 #endif
 240         v9inode->writeback_fid = NULL;
 241         v9inode->cache_validity = 0;
 242         mutex_init(&v9inode->v_mutex);
 243         return &v9inode->vfs_inode;
 244 }
 245
 246 /**
 247  * v9fs_destroy_inode - destroy an inode
 248  *
 249  */
 250
 251 static void v9fs_i_callback(struct rcu_head *head)
 252 {
 253         struct inode *inode = container_of(head, struct inode, i_rcu);
 254         INIT_LIST_HEAD(&inode->i_dentry);
 255         kmem_cache_free(v9fs_inode_cache, V9FS_I(inode));
 256 }
 257
 258 void v9fs_destroy_inode(struct inode *inode)
 259 {
 260         call_rcu(&inode->i_rcu, v9fs_i_callback);
 261 }
 262
 263 int v9fs_init_inode(struct v9fs_session_info *v9ses,
 264                     struct inode *inode, int mode, dev_t rdev)
 265 {
 266         int err = 0;
 267
 268         inode_init_owner(inode, NULL, mode);
 269         inode->i_blocks = 0;
 270         inode->i_rdev = rdev;
 271         inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 272         inode->i_mapping->a_ops = &v9fs_addr_operations;
 273
 274         switch (mode & S_IFMT) {
 275         case S_IFIFO:
 276         case S_IFBLK:
 277         case S_IFCHR:
 278         case S_IFSOCK:
 279                 if (v9fs_proto_dotl(v9ses)) {
 280                         inode->i_op = &v9fs_file_inode_operations_dotl;
 281                 } else if (v9fs_proto_dotu(v9ses)) {
 282                         inode->i_op = &v9fs_file_inode_operations;
 283                 } else {
 284                         P9_DPRINTK(P9_DEBUG_ERROR,
 285                                    "special files without extended mode\n");
 286                         err = -EINVAL;
 287                         goto error;
 288                 }
 289                 init_special_inode(inode, inode->i_mode, inode->i_rdev);
 290                 break;
 291         case S_IFREG:
 292                 if (v9fs_proto_dotl(v9ses)) {
 293                         inode->i_op = &v9fs_file_inode_operations_dotl;
 294                         if (v9ses->cache)
 295                                 inode->i_fop =
 296                                         &v9fs_cached_file_operations_dotl;
 297                         else
 298                                 inode->i_fop = &v9fs_file_operations_dotl;
 299                 } else {
 300                         inode->i_op = &v9fs_file_inode_operations;
 301                         if (v9ses->cache)
 302                                 inode->i_fop = &v9fs_cached_file_operations;
 303                         else
 304                                 inode->i_fop = &v9fs_file_operations;
 305                 }
 306
 307                 break;
 308         case S_IFLNK:
 309                 if (!v9fs_proto_dotu(v9ses) && !v9fs_proto_dotl(v9ses)) {
 310                         P9_DPRINTK(P9_DEBUG_ERROR, "extended modes used with "
 311                                                 "legacy protocol.\n");
 312                         err = -EINVAL;
 313                         goto error;
 314                 }
 315
 316                 if (v9fs_proto_dotl(v9ses))
 317                         inode->i_op = &v9fs_symlink_inode_operations_dotl;
 318                 else
 319                         inode->i_op = &v9fs_symlink_inode_operations;
 320
 321                 break;
 322         case S_IFDIR:
 323                 inc_nlink(inode);
 324                 if (v9fs_proto_dotl(v9ses))
 325                         inode->i_op = &v9fs_dir_inode_operations_dotl;
 326                 else if (v9fs_proto_dotu(v9ses))
 327                         inode->i_op = &v9fs_dir_inode_operations_dotu;
 328                 else
 329                         inode->i_op = &v9fs_dir_inode_operations;
 330
 331                 if (v9fs_proto_dotl(v9ses))
 332                         inode->i_fop = &v9fs_dir_operations_dotl;
 333                 else
 334                         inode->i_fop = &v9fs_dir_operations;
 335
 336                 break;
 337         default:
 338                 P9_DPRINTK(P9_DEBUG_ERROR, "BAD mode 0x%x S_IFMT 0x%x\n",
 339                            mode, mode & S_IFMT);
 340                 err = -EINVAL;
 341                 goto error;
 342         }
 343 error:
 344         return err;
 345
 346 }
 347
 348 /**
 349  * v9fs_get_inode - helper function to setup an inode
 350  * @sb: superblock
 351  * @mode: mode to setup inode with
 352  *
 353  */
 354
 355 struct inode *v9fs_get_inode(struct super_block *sb, int mode, dev_t rdev)
 356 {
 357         int err;
 358         struct inode *inode;
 359         struct v9fs_session_info *v9ses = sb->s_fs_info;
 360
 361         P9_DPRINTK(P9_DEBUG_VFS, "super block: %p mode: %o\n", sb, mode);
 362
 363         inode = new_inode(sb);
 364         if (!inode) {
 365                 P9_EPRINTK(KERN_WARNING, "Problem allocating inode\n");
 366                 return ERR_PTR(-ENOMEM);
 367         }
 368         err = v9fs_init_inode(v9ses, inode, mode, rdev);
 369         if (err) {
 370                 iput(inode);
 371                 return ERR_PTR(err);
 372         }
 373         return inode;
 374 }
 375
 376 /*
 377 static struct v9fs_fid*
 378 v9fs_clone_walk(struct v9fs_session_info *v9ses, u32 fid, struct dentry *dentry)
 379 {
 380         int err;
 381         int nfid;
 382         struct v9fs_fid *ret;
 383         struct v9fs_fcall *fcall;
 384
 385         nfid = v9fs_get_idpool(&v9ses->fidpool);
 386         if (nfid < 0) {
 387                 eprintk(KERN_WARNING, "no free fids available\n");
 388                 return ERR_PTR(-ENOSPC);
 389         }
 390
 391         err = v9fs_t_walk(v9ses, fid, nfid, (char *) dentry->d_name.name,
 392                 &fcall);
 393
 394         if (err < 0) {
 395                 if (fcall && fcall->id == RWALK)
 396                         goto clunk_fid;
 397
 398                 PRINT_FCALL_ERROR("walk error", fcall);
 399                 v9fs_put_idpool(nfid, &v9ses->fidpool);
 400                 goto error;
 401         }
 402
 403         kfree(fcall);
 404         fcall = NULL;
 405         ret = v9fs_fid_create(v9ses, nfid);
 406         if (!ret) {
 407                 err = -ENOMEM;
 408                 goto clunk_fid;
 409         }
 410
 411         err = v9fs_fid_insert(ret, dentry);
 412         if (err < 0) {
 413                 v9fs_fid_destroy(ret);
 414                 goto clunk_fid;
 415         }
 416
 417         return ret;
 418
 419 clunk_fid:
 420         v9fs_t_clunk(v9ses, nfid);
 421
 422 error:
 423         kfree(fcall);
 424         return ERR_PTR(err);
 425 }
 426 */
 427
 428
 429 /**
 430  * v9fs_clear_inode - release an inode
 431  * @inode: inode to release
 432  *
 433  */
 434 void v9fs_evict_inode(struct inode *inode)
 435 {
 436         struct v9fs_inode *v9inode = V9FS_I(inode);
 437
 438         truncate_inode_pages(inode->i_mapping, 0);
 439         end_writeback(inode);
 440         filemap_fdatawrite(inode->i_mapping);
 441
 442 #ifdef CONFIG_9P_FSCACHE
 443         v9fs_cache_inode_put_cookie(inode);
 444 #endif
 445         /* clunk the fid stashed in writeback_fid */
 446         if (v9inode->writeback_fid) {
 447                 p9_client_clunk(v9inode->writeback_fid);
 448                 v9inode->writeback_fid = NULL;
 449         }
 450 }
 451
 452 static int v9fs_test_inode(struct inode *inode, void *data)
 453 {
 454         int umode;
 455         dev_t rdev;
 456         struct v9fs_inode *v9inode = V9FS_I(inode);
 457         struct p9_wstat *st = (struct p9_wstat *)data;
 458         struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
 459
 460         umode = p9mode2unixmode(v9ses, st, &rdev);
 461         /* don't match inode of different type */
 462         if ((inode->i_mode & S_IFMT) != (umode & S_IFMT))
 463                 return 0;
 464
 465         /* compare qid details */
 466         if (memcmp(&v9inode->qid.version,
 467                    &st->qid.version, sizeof(v9inode->qid.version)))
 468                 return 0;
 469
 470         if (v9inode->qid.type != st->qid.type)
 471                 return 0;
 472         return 1;
 473 }
 474
 475 static int v9fs_test_new_inode(struct inode *inode, void *data)
 476 {
 477         return 0;
 478 }
 479
 480 static int v9fs_set_inode(struct inode *inode,  void *data)
 481 {
 482         struct v9fs_inode *v9inode = V9FS_I(inode);
 483         struct p9_wstat *st = (struct p9_wstat *)data;
 484
 485         memcpy(&v9inode->qid, &st->qid, sizeof(st->qid));
 486         return 0;
 487 }
 488
 489 static struct inode *v9fs_qid_iget(struct super_block *sb,
 490                                    struct p9_qid *qid,
 491                                    struct p9_wstat *st,
 492                                    int new)
 493 {
 494         dev_t rdev;
 495         int retval, umode;
 496         unsigned long i_ino;
 497         struct inode *inode;
 498         struct v9fs_session_info *v9ses = sb->s_fs_info;
 499         int (*test)(struct inode *, void *);
 500
 501         if (new)
 502                 test = v9fs_test_new_inode;
 503         else
 504                 test = v9fs_test_inode;
 505
 506         i_ino = v9fs_qid2ino(qid);
 507         inode = iget5_locked(sb, i_ino, test, v9fs_set_inode, st);
 508         if (!inode)
 509                 return ERR_PTR(-ENOMEM);
 510         if (!(inode->i_state & I_NEW))
 511                 return inode;
 512         /*
 513          * initialize the inode with the stat info
 514          * FIXME!! we may need support for stale inodes
 515          * later.
 516          */
 517         inode->i_ino = i_ino;
 518         umode = p9mode2unixmode(v9ses, st, &rdev);
 519         retval = v9fs_init_inode(v9ses, inode, umode, rdev);
 520         if (retval)
 521                 goto error;
 522
 523         v9fs_stat2inode(st, inode, sb);
 524 #ifdef CONFIG_9P_FSCACHE
 525         v9fs_cache_inode_get_cookie(inode);
 526 #endif
 527         unlock_new_inode(inode);
 528         return inode;
 529 error:
 530         unlock_new_inode(inode);
 531         iput(inode);
 532         return ERR_PTR(retval);
 533
 534 }
 535
 536 struct inode *
 537 v9fs_inode_from_fid(struct v9fs_session_info *v9ses, struct p9_fid *fid,
 538                     struct super_block *sb, int new)
 539 {
 540         struct p9_wstat *st;
 541         struct inode *inode = NULL;
 542
 543         st = p9_client_stat(fid);
 544         if (IS_ERR(st))
 545                 return ERR_CAST(st);
 546
 547         inode = v9fs_qid_iget(sb, &st->qid, st, new);
 548         p9stat_free(st);
 549         kfree(st);
 550         return inode;
 551 }
 552
 553 /**
 554  * v9fs_at_to_dotl_flags- convert Linux specific AT flags to
 555  * plan 9 AT flag.
 556  * @flags: flags to convert
 557  */
 558 static int v9fs_at_to_dotl_flags(int flags)
 559 {
 560         int rflags = 0;
 561         if (flags & AT_REMOVEDIR)
 562                 rflags |= P9_DOTL_AT_REMOVEDIR;
 563         return rflags;
 564 }
 565
 566 /**
 567  * v9fs_remove - helper function to remove files and directories
 568  * @dir: directory inode that is being deleted
 569  * @dentry:  dentry that is being deleted
 570  * @rmdir: removing a directory
 571  *
 572  */
 573
 574 static int v9fs_remove(struct inode *dir, struct dentry *dentry, int flags)
 575 {
 576         struct inode *inode;
 577         int retval = -EOPNOTSUPP;
 578         struct p9_fid *v9fid, *dfid;
 579         struct v9fs_session_info *v9ses;
 580
 581         P9_DPRINTK(P9_DEBUG_VFS, "inode: %p dentry: %p rmdir: %x\n",
 582                    dir, dentry, flags);
 583
 584         v9ses = v9fs_inode2v9ses(dir);
 585         inode = dentry->d_inode;
 586         dfid = v9fs_fid_lookup(dentry->d_parent);
 587         if (IS_ERR(dfid)) {
 588                 retval = PTR_ERR(dfid);
 589                 P9_DPRINTK(P9_DEBUG_VFS, "fid lookup failed %d\n", retval);
 590                 return retval;
 591         }
 592         if (v9fs_proto_dotl(v9ses))
 593                 retval = p9_client_unlinkat(dfid, dentry->d_name.name,
 594                                             v9fs_at_to_dotl_flags(flags));
 595         if (retval == -EOPNOTSUPP) {
 596                 /* Try the one based on path */
 597                 v9fid = v9fs_fid_clone(dentry);
 598                 if (IS_ERR(v9fid))
 599                         return PTR_ERR(v9fid);
 600                 retval = p9_client_remove(v9fid);
 601         }
 602         if (!retval) {
 603                 /*
 604                  * directories on unlink should have zero
 605                  * link count
 606                  */
 607                 if (flags & AT_REMOVEDIR) {
 608                         clear_nlink(inode);
 609                         drop_nlink(dir);
 610                 } else
 611                         drop_nlink(inode);
 612
 613                 v9fs_invalidate_inode_attr(inode);
 614                 v9fs_invalidate_inode_attr(dir);
 615         }
 616         return retval;
 617 }
 618
 619 /**
 620  * v9fs_create - Create a file
 621  * @v9ses: session information
 622  * @dir: directory that dentry is being created in
 623  * @dentry:  dentry that is being created
 624  * @extension: 9p2000.u extension string to support devices, etc.
 625  * @perm: create permissions
 626  * @mode: open mode
 627  *
 628  */
 629 static struct p9_fid *
 630 v9fs_create(struct v9fs_session_info *v9ses, struct inode *dir,
 631                 struct dentry *dentry, char *extension, u32 perm, u8 mode)
 632 {
 633         int err;
 634         char *name;
 635         struct p9_fid *dfid, *ofid, *fid;
 636         struct inode *inode;
 637
 638         P9_DPRINTK(P9_DEBUG_VFS, "name %s\n", dentry->d_name.name);
 639
 640         err = 0;
 641         ofid = NULL;
 642         fid = NULL;
 643         name = (char *) dentry->d_name.name;
 644         dfid = v9fs_fid_lookup(dentry->d_parent);
 645         if (IS_ERR(dfid)) {
 646                 err = PTR_ERR(dfid);
 647                 P9_DPRINTK(P9_DEBUG_VFS, "fid lookup failed %d\n", err);
 648                 return ERR_PTR(err);
 649         }
 650
 651         /* clone a fid to use for creation */
 652         ofid = p9_client_walk(dfid, 0, NULL, 1);
 653         if (IS_ERR(ofid)) {
 654                 err = PTR_ERR(ofid);
 655                 P9_DPRINTK(P9_DEBUG_VFS, "p9_client_walk failed %d\n", err);
 656                 return ERR_PTR(err);
 657         }
 658
 659         err = p9_client_fcreate(ofid, name, perm, mode, extension);
 660         if (err < 0) {
 661                 P9_DPRINTK(P9_DEBUG_VFS, "p9_client_fcreate failed %d\n", err);
 662                 goto error;
 663         }
 664
 665         /* now walk from the parent so we can get unopened fid */
 666         fid = p9_client_walk(dfid, 1, &name, 1);
 667         if (IS_ERR(fid)) {
 668                 err = PTR_ERR(fid);
 669                 P9_DPRINTK(P9_DEBUG_VFS, "p9_client_walk failed %d\n", err);
 670                 fid = NULL;
 671                 goto error;
 672         }
 673
 674         /* instantiate inode and assign the unopened fid to the dentry */
 675         inode = v9fs_get_new_inode_from_fid(v9ses, fid, dir->i_sb);
 676         if (IS_ERR(inode)) {
 677                 err = PTR_ERR(inode);
 678                 P9_DPRINTK(P9_DEBUG_VFS, "inode creation failed %d\n", err);
 679                 goto error;
 680         }
 681         err = v9fs_fid_add(dentry, fid);
 682         if (err < 0)
 683                 goto error;
 684         d_instantiate(dentry, inode);
 685         return ofid;
 686 error:
 687         if (ofid)
 688                 p9_client_clunk(ofid);
 689
 690         if (fid)
 691                 p9_client_clunk(fid);
 692
 693         return ERR_PTR(err);
 694 }
 695
 696 /**
 697  * v9fs_vfs_create - VFS hook to create files
 698  * @dir: directory inode that is being created
 699  * @dentry:  dentry that is being deleted
 700  * @mode: create permissions
 701  * @nd: path information
 702  *
 703  */
 704
 705 static int
 706 v9fs_vfs_create(struct inode *dir, struct dentry *dentry, int mode,
 707                 struct nameidata *nd)
 708 {
 709         int err;
 710         u32 perm;
 711         int flags;
 712         struct file *filp;
 713         struct v9fs_inode *v9inode;
 714         struct v9fs_session_info *v9ses;
 715         struct p9_fid *fid, *inode_fid;
 716
 717         err = 0;
 718         fid = NULL;
 719         v9ses = v9fs_inode2v9ses(dir);
 720         perm = unixmode2p9mode(v9ses, mode);
 721         if (nd)
 722                 flags = nd->intent.open.flags;
 723         else
 724                 flags = O_RDWR;
 725
 726         fid = v9fs_create(v9ses, dir, dentry, NULL, perm,
 727                                 v9fs_uflags2omode(flags,
 728                                                 v9fs_proto_dotu(v9ses)));
 729         if (IS_ERR(fid)) {
 730                 err = PTR_ERR(fid);
 731                 fid = NULL;
 732                 goto error;
 733         }
 734
 735         v9fs_invalidate_inode_attr(dir);
 736         /* if we are opening a file, assign the open fid to the file */
 737         if (nd) {
 738                 v9inode = V9FS_I(dentry->d_inode);
 739                 mutex_lock(&v9inode->v_mutex);
 740                 if (v9ses->cache && !v9inode->writeback_fid &&
 741                     ((flags & O_ACCMODE) != O_RDONLY)) {
 742                         /*
 743                          * clone a fid and add it to writeback_fid
 744                          * we do it during open time instead of
 745                          * page dirty time via write_begin/page_mkwrite
 746                          * because we want write after unlink usecase
 747                          * to work.
 748                          */
 749                         inode_fid = v9fs_writeback_fid(dentry);
 750                         if (IS_ERR(inode_fid)) {
 751                                 err = PTR_ERR(inode_fid);
 752                                 mutex_unlock(&v9inode->v_mutex);
 753                                 goto error;
 754                         }
 755                         v9inode->writeback_fid = (void *) inode_fid;
 756                 }
 757                 mutex_unlock(&v9inode->v_mutex);
 758                 filp = lookup_instantiate_filp(nd, dentry, generic_file_open);
 759                 if (IS_ERR(filp)) {
 760                         err = PTR_ERR(filp);
 761                         goto error;
 762                 }
 763
 764                 filp->private_data = fid;
 765 #ifdef CONFIG_9P_FSCACHE
 766                 if (v9ses->cache)
 767                         v9fs_cache_inode_set_cookie(dentry->d_inode, filp);
 768 #endif
 769         } else
 770                 p9_client_clunk(fid);
 771
 772         return 0;
 773
 774 error:
 775         if (fid)
 776                 p9_client_clunk(fid);
 777
 778         return err;
 779 }
 780
 781 /**
 782  * v9fs_vfs_mkdir - VFS mkdir hook to create a directory
 783  * @dir:  inode that is being unlinked
 784  * @dentry: dentry that is being unlinked
 785  * @mode: mode for new directory
 786  *
 787  */
 788
 789 static int v9fs_vfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 790 {
 791         int err;
 792         u32 perm;
 793         struct p9_fid *fid;
 794         struct v9fs_session_info *v9ses;
 795
 796         P9_DPRINTK(P9_DEBUG_VFS, "name %s\n", dentry->d_name.name);
 797         err = 0;
 798         v9ses = v9fs_inode2v9ses(dir);
 799         perm = unixmode2p9mode(v9ses, mode | S_IFDIR);
 800         fid = v9fs_create(v9ses, dir, dentry, NULL, perm, P9_OREAD);
 801         if (IS_ERR(fid)) {
 802                 err = PTR_ERR(fid);
 803                 fid = NULL;
 804         } else {
 805                 inc_nlink(dir);
 806                 v9fs_invalidate_inode_attr(dir);
 807         }
 808
 809         if (fid)
 810                 p9_client_clunk(fid);
 811
 812         return err;
 813 }
 814
 815 /**
 816  * v9fs_vfs_lookup - VFS lookup hook to "walk" to a new inode
 817  * @dir:  inode that is being walked from
 818  * @dentry: dentry that is being walked to?
 819  * @nameidata: path data
 820  *
 821  */
 822
 823 struct dentry *v9fs_vfs_lookup(struct inode *dir, struct dentry *dentry,
 824                                       struct nameidata *nameidata)
 825 {
 826         struct dentry *res;
 827         struct super_block *sb;
 828         struct v9fs_session_info *v9ses;
 829         struct p9_fid *dfid, *fid;
 830         struct inode *inode;
 831         char *name;
 832         int result = 0;
 833
 834         P9_DPRINTK(P9_DEBUG_VFS, "dir: %p dentry: (%s) %p nameidata: %p\n",
 835                 dir, dentry->d_name.name, dentry, nameidata);
 836
 837         if (dentry->d_name.len > NAME_MAX)
 838                 return ERR_PTR(-ENAMETOOLONG);
 839
 840         sb = dir->i_sb;
 841         v9ses = v9fs_inode2v9ses(dir);
 842         /* We can walk d_parent because we hold the dir->i_mutex */
 843         dfid = v9fs_fid_lookup(dentry->d_parent);
 844         if (IS_ERR(dfid))
 845                 return ERR_CAST(dfid);
 846
 847         name = (char *) dentry->d_name.name;
 848         fid = p9_client_walk(dfid, 1, &name, 1);
 849         if (IS_ERR(fid)) {
 850                 result = PTR_ERR(fid);
 851                 if (result == -ENOENT) {
 852                         inode = NULL;
 853                         goto inst_out;
 854                 }
 855
 856                 return ERR_PTR(result);
 857         }
 858         /*
 859          * Make sure we don't use a wrong inode due to parallel
 860          * unlink. For cached mode create calls request for new
 861          * inode. But with cache disabled, lookup should do this.
 862          */
 863         if (v9ses->cache)
 864                 inode = v9fs_get_inode_from_fid(v9ses, fid, dir->i_sb);
 865         else
 866                 inode = v9fs_get_new_inode_from_fid(v9ses, fid, dir->i_sb);
 867         if (IS_ERR(inode)) {
 868                 result = PTR_ERR(inode);
 869                 inode = NULL;
 870                 goto error;
 871         }
 872         result = v9fs_fid_add(dentry, fid);
 873         if (result < 0)
 874                 goto error_iput;
 875 inst_out:
 876         /*
 877          * If we had a rename on the server and a parallel lookup
 878          * for the new name, then make sure we instantiate with
 879          * the new name. ie look up for a/b, while on server somebody
 880          * moved b under k and client parallely did a lookup for
 881          * k/b.
 882          */
 883         res = d_materialise_unique(dentry, inode);
 884         if (!IS_ERR(res))
 885                 return res;
 886         result = PTR_ERR(res);
 887 error_iput:
 888         iput(inode);
 889 error:
 890         p9_client_clunk(fid);
 891
 892         return ERR_PTR(result);
 893 }
 894
 895 /**
 896  * v9fs_vfs_unlink - VFS unlink hook to delete an inode
 897  * @i:  inode that is being unlinked
 898  * @d: dentry that is being unlinked
 899  *
 900  */
 901
 902 int v9fs_vfs_unlink(struct inode *i, struct dentry *d)
 903 {
 904         return v9fs_remove(i, d, 0);
 905 }
 906
 907 /**
 908  * v9fs_vfs_rmdir - VFS unlink hook to delete a directory
 909  * @i:  inode that is being unlinked
 910  * @d: dentry that is being unlinked
 911  *
 912  */
 913
 914 int v9fs_vfs_rmdir(struct inode *i, struct dentry *d)
 915 {
 916         return v9fs_remove(i, d, AT_REMOVEDIR);
 917 }
 918
 919 /**
 920  * v9fs_vfs_rename - VFS hook to rename an inode
 921  * @old_dir:  old dir inode
 922  * @old_dentry: old dentry
 923  * @new_dir: new dir inode
 924  * @new_dentry: new dentry
 925  *
 926  */
 927
 928 int
 929 v9fs_vfs_rename(struct inode *old_dir, struct dentry *old_dentry,
 930                 struct inode *new_dir, struct dentry *new_dentry)
 931 {
 932         int retval;
 933         struct inode *old_inode;
 934         struct inode *new_inode;
 935         struct v9fs_session_info *v9ses;
 936         struct p9_fid *oldfid;
 937         struct p9_fid *olddirfid;
 938         struct p9_fid *newdirfid;
 939         struct p9_wstat wstat;
 940
 941         P9_DPRINTK(P9_DEBUG_VFS, "\n");
 942         retval = 0;
 943         old_inode = old_dentry->d_inode;
 944         new_inode = new_dentry->d_inode;
 945         v9ses = v9fs_inode2v9ses(old_inode);
 946         oldfid = v9fs_fid_lookup(old_dentry);
 947         if (IS_ERR(oldfid))
 948                 return PTR_ERR(oldfid);
 949
 950         olddirfid = v9fs_fid_clone(old_dentry->d_parent);
 951         if (IS_ERR(olddirfid)) {
 952                 retval = PTR_ERR(olddirfid);
 953                 goto done;
 954         }
 955
 956         newdirfid = v9fs_fid_clone(new_dentry->d_parent);
 957         if (IS_ERR(newdirfid)) {
 958                 retval = PTR_ERR(newdirfid);
 959                 goto clunk_olddir;
 960         }
 961
 962         down_write(&v9ses->rename_sem);
 963         if (v9fs_proto_dotl(v9ses)) {
 964                 retval = p9_client_renameat(olddirfid, old_dentry->d_name.name,
 965                                             newdirfid, new_dentry->d_name.name);
 966                 if (retval == -EOPNOTSUPP)
 967                         retval = p9_client_rename(oldfid, newdirfid,
 968                                                   new_dentry->d_name.name);
 969                 if (retval != -EOPNOTSUPP)
 970                         goto clunk_newdir;
 971         }
 972         if (old_dentry->d_parent != new_dentry->d_parent) {
 973                 /*
 974                  * 9P .u can only handle file rename in the same directory
 975                  */
 976
 977                 P9_DPRINTK(P9_DEBUG_ERROR,
 978                                 "old dir and new dir are different\n");
 979                 retval = -EXDEV;
 980                 goto clunk_newdir;
 981         }
 982         v9fs_blank_wstat(&wstat);
 983         wstat.muid = v9ses->uname;
 984         wstat.name = (char *) new_dentry->d_name.name;
 985         retval = p9_client_wstat(oldfid, &wstat);
 986
 987 clunk_newdir:
 988         if (!retval) {
 989                 if (new_inode) {
 990                         if (S_ISDIR(new_inode->i_mode))
 991                                 clear_nlink(new_inode);
 992                         else
 993                                 drop_nlink(new_inode);
 994                 }
 995                 if (S_ISDIR(old_inode->i_mode)) {
 996                         if (!new_inode)
 997                                 inc_nlink(new_dir);
 998                         drop_nlink(old_dir);
 999                 }
1000                 v9fs_invalidate_inode_attr(old_inode);
1001                 v9fs_invalidate_inode_attr(old_dir);
1002                 v9fs_invalidate_inode_attr(new_dir);
1003
1004                 /* successful rename */
1005                 d_move(old_dentry, new_dentry);
1006         }
1007         up_write(&v9ses->rename_sem);
1008         p9_client_clunk(newdirfid);
1009
1010 clunk_olddir:
1011         p9_client_clunk(olddirfid);
1012
1013 done:
1014         return retval;
1015 }
1016
1017 /**
1018  * v9fs_vfs_getattr - retrieve file metadata
1019  * @mnt: mount information
1020  * @dentry: file to get attributes on
1021  * @stat: metadata structure to populate
1022  *
1023  */
1024
1025 static int
1026 v9fs_vfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
1027                  struct kstat *stat)
1028 {
1029         int err;
1030         struct v9fs_session_info *v9ses;
1031         struct p9_fid *fid;
1032         struct p9_wstat *st;
1033
1034         P9_DPRINTK(P9_DEBUG_VFS, "dentry: %p\n", dentry);
1035         err = -EPERM;
1036         v9ses = v9fs_dentry2v9ses(dentry);
1037         if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE) {
1038                 generic_fillattr(dentry->d_inode, stat);
1039                 return 0;
1040         }
1041         fid = v9fs_fid_lookup(dentry);
1042         if (IS_ERR(fid))
1043                 return PTR_ERR(fid);
1044
1045         st = p9_client_stat(fid);
1046         if (IS_ERR(st))
1047                 return PTR_ERR(st);
1048
1049         v9fs_stat2inode(st, dentry->d_inode, dentry->d_inode->i_sb);
1050         generic_fillattr(dentry->d_inode, stat);
1051
1052         p9stat_free(st);
1053         kfree(st);
1054         return 0;
1055 }
1056
1057 /**
1058  * v9fs_vfs_setattr - set file metadata
1059  * @dentry: file whose metadata to set
1060  * @iattr: metadata assignment structure
1061  *
1062  */
1063
1064 static int v9fs_vfs_setattr(struct dentry *dentry, struct iattr *iattr)
1065 {
1066         int retval;
1067         struct v9fs_session_info *v9ses;
1068         struct p9_fid *fid;
1069         struct p9_wstat wstat;
1070
1071         P9_DPRINTK(P9_DEBUG_VFS, "\n");
1072         retval = inode_change_ok(dentry->d_inode, iattr);
1073         if (retval)
1074                 return retval;
1075
1076         retval = -EPERM;
1077         v9ses = v9fs_dentry2v9ses(dentry);
1078         fid = v9fs_fid_lookup(dentry);
1079         if(IS_ERR(fid))
1080                 return PTR_ERR(fid);
1081
1082         v9fs_blank_wstat(&wstat);
1083         if (iattr->ia_valid & ATTR_MODE)
1084                 wstat.mode = unixmode2p9mode(v9ses, iattr->ia_mode);
1085
1086         if (iattr->ia_valid & ATTR_MTIME)
1087                 wstat.mtime = iattr->ia_mtime.tv_sec;
1088
1089         if (iattr->ia_valid & ATTR_ATIME)
1090                 wstat.atime = iattr->ia_atime.tv_sec;
1091
1092         if (iattr->ia_valid & ATTR_SIZE)
1093                 wstat.length = iattr->ia_size;
1094
1095         if (v9fs_proto_dotu(v9ses)) {
1096                 if (iattr->ia_valid & ATTR_UID)
1097                         wstat.n_uid = iattr->ia_uid;
1098
1099                 if (iattr->ia_valid & ATTR_GID)
1100                         wstat.n_gid = iattr->ia_gid;
1101         }
1102
1103         /* Write all dirty data */
1104         if (S_ISREG(dentry->d_inode->i_mode))
1105                 filemap_write_and_wait(dentry->d_inode->i_mapping);
1106
1107         retval = p9_client_wstat(fid, &wstat);
1108         if (retval < 0)
1109                 return retval;
1110
1111         if ((iattr->ia_valid & ATTR_SIZE) &&
1112             iattr->ia_size != i_size_read(dentry->d_inode))
1113                 truncate_setsize(dentry->d_inode, iattr->ia_size);
1114
1115         v9fs_invalidate_inode_attr(dentry->d_inode);
1116
1117         setattr_copy(dentry->d_inode, iattr);
1118         mark_inode_dirty(dentry->d_inode);
1119         return 0;
1120 }
1121
1122 /**
1123  * v9fs_stat2inode - populate an inode structure with mistat info
1124  * @stat: Plan 9 metadata (mistat) structure
1125  * @inode: inode to populate
1126  * @sb: superblock of filesystem
1127  *
1128  */
1129
1130 void
1131 v9fs_stat2inode(struct p9_wstat *stat, struct inode *inode,
1132         struct super_block *sb)
1133 {
1134         mode_t mode;
1135         char ext[32];
1136         char tag_name[14];
1137         unsigned int i_nlink;
1138         struct v9fs_session_info *v9ses = sb->s_fs_info;
1139         struct v9fs_inode *v9inode = V9FS_I(inode);
1140
1141         set_nlink(inode, 1);
1142
1143         inode->i_atime.tv_sec = stat->atime;
1144         inode->i_mtime.tv_sec = stat->mtime;
1145         inode->i_ctime.tv_sec = stat->mtime;
1146
1147         inode->i_uid = v9ses->dfltuid;
1148         inode->i_gid = v9ses->dfltgid;
1149
1150         if (v9fs_proto_dotu(v9ses)) {
1151                 inode->i_uid = stat->n_uid;
1152                 inode->i_gid = stat->n_gid;
1153         }
1154         if ((S_ISREG(inode->i_mode)) || (S_ISDIR(inode->i_mode))) {
1155                 if (v9fs_proto_dotu(v9ses) && (stat->extension[0] != '\0')) {
1156                         /*
1157                          * Hadlink support got added later to
1158                          * to the .u extension. So there can be
1159                          * server out there that doesn't support
1160                          * this even with .u extension. So check
1161                          * for non NULL stat->extension
1162                          */
1163                         strncpy(ext, stat->extension, sizeof(ext));
1164                         /* HARDLINKCOUNT %u */
1165                         sscanf(ext, "%13s %u", tag_name, &i_nlink);
1166                         if (!strncmp(tag_name, "HARDLINKCOUNT", 13))
1167                                 set_nlink(inode, i_nlink);
1168                 }
1169         }
1170         mode = stat->mode & S_IALLUGO;
1171         mode |= inode->i_mode & ~S_IALLUGO;
1172         inode->i_mode = mode;
1173         i_size_write(inode, stat->length);
1174
1175         /* not real number of blocks, but 512 byte ones ... */
1176         inode->i_blocks = (i_size_read(inode) + 512 - 1) >> 9;
1177         v9inode->cache_validity &= ~V9FS_INO_INVALID_ATTR;
1178 }
1179
1180 /**
1181  * v9fs_qid2ino - convert qid into inode number
1182  * @qid: qid to hash
1183  *
1184  * BUG: potential for inode number collisions?
1185  */
1186
1187 ino_t v9fs_qid2ino(struct p9_qid *qid)
1188 {
1189         u64 path = qid->path + 2;
1190         ino_t i = 0;
1191
1192         if (sizeof(ino_t) == sizeof(path))
1193                 memcpy(&i, &path, sizeof(ino_t));
1194         else
1195                 i = (ino_t) (path ^ (path >> 32));
1196
1197         return i;
1198 }
1199
1200 /**
1201  * v9fs_readlink - read a symlink's location (internal version)
1202  * @dentry: dentry for symlink
1203  * @buffer: buffer to load symlink location into
1204  * @buflen: length of buffer
1205  *
1206  */
1207
1208 static int v9fs_readlink(struct dentry *dentry, char *buffer, int buflen)
1209 {
1210         int retval;
1211
1212         struct v9fs_session_info *v9ses;
1213         struct p9_fid *fid;
1214         struct p9_wstat *st;
1215
1216         P9_DPRINTK(P9_DEBUG_VFS, " %s\n", dentry->d_name.name);
1217         retval = -EPERM;
1218         v9ses = v9fs_dentry2v9ses(dentry);
1219         fid = v9fs_fid_lookup(dentry);
1220         if (IS_ERR(fid))
1221                 return PTR_ERR(fid);
1222
1223         if (!v9fs_proto_dotu(v9ses))
1224                 return -EBADF;
1225
1226         st = p9_client_stat(fid);
1227         if (IS_ERR(st))
1228                 return PTR_ERR(st);
1229
1230         if (!(st->mode & P9_DMSYMLINK)) {
1231                 retval = -EINVAL;
1232                 goto done;
1233         }
1234
1235         /* copy extension buffer into buffer */
1236         strncpy(buffer, st->extension, buflen);
1237
1238         P9_DPRINTK(P9_DEBUG_VFS,
1239                 "%s -> %s (%s)\n", dentry->d_name.name, st->extension, buffer);
1240
1241         retval = strnlen(buffer, buflen);
1242 done:
1243         p9stat_free(st);
1244         kfree(st);
1245         return retval;
1246 }
1247
1248 /**
1249  * v9fs_vfs_follow_link - follow a symlink path
1250  * @dentry: dentry for symlink
1251  * @nd: nameidata
1252  *
1253  */
1254
1255 static void *v9fs_vfs_follow_link(struct dentry *dentry, struct nameidata *nd)
1256 {
1257         int len = 0;
1258         char *link = __getname();
1259
1260         P9_DPRINTK(P9_DEBUG_VFS, "%s n", dentry->d_name.name);
1261
1262         if (!link)
1263                 link = ERR_PTR(-ENOMEM);
1264         else {
1265                 len = v9fs_readlink(dentry, link, PATH_MAX);
1266
1267                 if (len < 0) {
1268                         __putname(link);
1269                         link = ERR_PTR(len);
1270                 } else
1271                         link[min(len, PATH_MAX-1)] = 0;
1272         }
1273         nd_set_link(nd, link);
1274
1275         return NULL;
1276 }
1277
1278 /**
1279  * v9fs_vfs_put_link - release a symlink path
1280  * @dentry: dentry for symlink
1281  * @nd: nameidata
1282  * @p: unused
1283  *
1284  */
1285
1286 void
1287 v9fs_vfs_put_link(struct dentry *dentry, struct nameidata *nd, void *p)
1288 {
1289         char *s = nd_get_link(nd);
1290
1291         P9_DPRINTK(P9_DEBUG_VFS, " %s %s\n", dentry->d_name.name,
1292                 IS_ERR(s) ? "<error>" : s);
1293         if (!IS_ERR(s))
1294                 __putname(s);
1295 }
1296
1297 /**
1298  * v9fs_vfs_mkspecial - create a special file
1299  * @dir: inode to create special file in
1300  * @dentry: dentry to create
1301  * @mode: mode to create special file
1302  * @extension: 9p2000.u format extension string representing special file
1303  *
1304  */
1305
1306 static int v9fs_vfs_mkspecial(struct inode *dir, struct dentry *dentry,
1307         int mode, const char *extension)
1308 {
1309         u32 perm;
1310         struct p9_fid *fid;
1311         struct v9fs_session_info *v9ses;
1312
1313         v9ses = v9fs_inode2v9ses(dir);
1314         if (!v9fs_proto_dotu(v9ses)) {
1315                 P9_DPRINTK(P9_DEBUG_ERROR, "not extended\n");
1316                 return -EPERM;
1317         }
1318
1319         perm = unixmode2p9mode(v9ses, mode);
1320         fid = v9fs_create(v9ses, dir, dentry, (char *) extension, perm,
1321                                                                 P9_OREAD);
1322         if (IS_ERR(fid))
1323                 return PTR_ERR(fid);
1324
1325         v9fs_invalidate_inode_attr(dir);
1326         p9_client_clunk(fid);
1327         return 0;
1328 }
1329
1330 /**
1331  * v9fs_vfs_symlink - helper function to create symlinks
1332  * @dir: directory inode containing symlink
1333  * @dentry: dentry for symlink
1334  * @symname: symlink data
1335  *
1336  * See Also: 9P2000.u RFC for more information
1337  *
1338  */
1339
1340 static int
1341 v9fs_vfs_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
1342 {
1343         P9_DPRINTK(P9_DEBUG_VFS, " %lu,%s,%s\n", dir->i_ino,
1344                                         dentry->d_name.name, symname);
1345
1346         return v9fs_vfs_mkspecial(dir, dentry, S_IFLNK, symname);
1347 }
1348
1349 /**
1350  * v9fs_vfs_link - create a hardlink
1351  * @old_dentry: dentry for file to link to
1352  * @dir: inode destination for new link
1353  * @dentry: dentry for link
1354  *
1355  */
1356
1357 static int
1358 v9fs_vfs_link(struct dentry *old_dentry, struct inode *dir,
1359               struct dentry *dentry)
1360 {
1361         int retval;
1362         char *name;
1363         struct p9_fid *oldfid;
1364
1365         P9_DPRINTK(P9_DEBUG_VFS,
1366                 " %lu,%s,%s\n", dir->i_ino, dentry->d_name.name,
1367                 old_dentry->d_name.name);
1368
1369         oldfid = v9fs_fid_clone(old_dentry);
1370         if (IS_ERR(oldfid))
1371                 return PTR_ERR(oldfid);
1372
1373         name = __getname();
1374         if (unlikely(!name)) {
1375                 retval = -ENOMEM;
1376                 goto clunk_fid;
1377         }
1378
1379         sprintf(name, "%d\n", oldfid->fid);
1380         retval = v9fs_vfs_mkspecial(dir, dentry, P9_DMLINK, name);
1381         __putname(name);
1382         if (!retval) {
1383                 v9fs_refresh_inode(oldfid, old_dentry->d_inode);
1384                 v9fs_invalidate_inode_attr(dir);
1385         }
1386 clunk_fid:
1387         p9_client_clunk(oldfid);
1388         return retval;
1389 }
1390
1391 /**
1392  * v9fs_vfs_mknod - create a special file
1393  * @dir: inode destination for new link
1394  * @dentry: dentry for file
1395  * @mode: mode for creation
1396  * @rdev: device associated with special file
1397  *
1398  */
1399
1400 static int
1401 v9fs_vfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t rdev)
1402 {
1403         int retval;
1404         char *name;
1405
1406         P9_DPRINTK(P9_DEBUG_VFS,
1407                 " %lu,%s mode: %x MAJOR: %u MINOR: %u\n", dir->i_ino,
1408                 dentry->d_name.name, mode, MAJOR(rdev), MINOR(rdev));
1409
1410         if (!new_valid_dev(rdev))
1411                 return -EINVAL;
1412
1413         name = __getname();
1414         if (!name)
1415                 return -ENOMEM;
1416         /* build extension */
1417         if (S_ISBLK(mode))
1418                 sprintf(name, "b %u %u", MAJOR(rdev), MINOR(rdev));
1419         else if (S_ISCHR(mode))
1420                 sprintf(name, "c %u %u", MAJOR(rdev), MINOR(rdev));
1421         else if (S_ISFIFO(mode))
1422                 *name = 0;
1423         else if (S_ISSOCK(mode))
1424                 *name = 0;
1425         else {
1426                 __putname(name);
1427                 return -EINVAL;
1428         }
1429
1430         retval = v9fs_vfs_mkspecial(dir, dentry, mode, name);
1431         __putname(name);
1432
1433         return retval;
1434 }
1435
1436 int v9fs_refresh_inode(struct p9_fid *fid, struct inode *inode)
1437 {
1438         int umode;
1439         dev_t rdev;
1440         loff_t i_size;
1441         struct p9_wstat *st;
1442         struct v9fs_session_info *v9ses;
1443
1444         v9ses = v9fs_inode2v9ses(inode);
1445         st = p9_client_stat(fid);
1446         if (IS_ERR(st))
1447                 return PTR_ERR(st);
1448         /*
1449          * Don't update inode if the file type is different
1450          */
1451         umode = p9mode2unixmode(v9ses, st, &rdev);
1452         if ((inode->i_mode & S_IFMT) != (umode & S_IFMT))
1453                 goto out;
1454
1455         spin_lock(&inode->i_lock);
1456         /*
1457          * We don't want to refresh inode->i_size,
1458          * because we may have cached data
1459          */
1460         i_size = inode->i_size;
1461         v9fs_stat2inode(st, inode, inode->i_sb);
1462         if (v9ses->cache)
1463                 inode->i_size = i_size;
1464         spin_unlock(&inode->i_lock);
1465 out:
1466         p9stat_free(st);
1467         kfree(st);
1468         return 0;
1469 }
1470
1471 static const struct inode_operations v9fs_dir_inode_operations_dotu = {
1472         .create = v9fs_vfs_create,
1473         .lookup = v9fs_vfs_lookup,
1474         .symlink = v9fs_vfs_symlink,
1475         .link = v9fs_vfs_link,
1476         .unlink = v9fs_vfs_unlink,
1477         .mkdir = v9fs_vfs_mkdir,
1478         .rmdir = v9fs_vfs_rmdir,
1479         .mknod = v9fs_vfs_mknod,
1480         .rename = v9fs_vfs_rename,
1481         .getattr = v9fs_vfs_getattr,
1482         .setattr = v9fs_vfs_setattr,
1483 };
1484
1485 static const struct inode_operations v9fs_dir_inode_operations = {
1486         .create = v9fs_vfs_create,
1487         .lookup = v9fs_vfs_lookup,
1488         .unlink = v9fs_vfs_unlink,
1489         .mkdir = v9fs_vfs_mkdir,
1490         .rmdir = v9fs_vfs_rmdir,
1491         .mknod = v9fs_vfs_mknod,
1492         .rename = v9fs_vfs_rename,
1493         .getattr = v9fs_vfs_getattr,
1494         .setattr = v9fs_vfs_setattr,
1495 };
1496
1497 static const struct inode_operations v9fs_file_inode_operations = {
1498         .getattr = v9fs_vfs_getattr,
1499         .setattr = v9fs_vfs_setattr,
1500 };
1501
1502 static const struct inode_operations v9fs_symlink_inode_operations = {
1503         .readlink = generic_readlink,
1504         .follow_link = v9fs_vfs_follow_link,
1505         .put_link = v9fs_vfs_put_link,
1506         .getattr = v9fs_vfs_getattr,
1507         .setattr = v9fs_vfs_setattr,
1508 };
1509