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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  27
  28 #include <linux/module.h>
  29 #include <linux/errno.h>
  30 #include <linux/fs.h>
  31 #include <linux/file.h>
  32 #include <linux/pagemap.h>
  33 #include <linux/stat.h>
  34 #include <linux/string.h>
  35 #include <linux/inet.h>
  36 #include <linux/namei.h>
  37 #include <linux/idr.h>
  38 #include <linux/sched.h>
  39 #include <linux/slab.h>
  40 #include <linux/xattr.h>
  41 #include <linux/posix_acl.h>
  42 #include <net/9p/9p.h>
  43 #include <net/9p/client.h>
  44
  45 #include "v9fs.h"
  46 #include "v9fs_vfs.h"
  47 #include "fid.h"
  48 #include "cache.h"
  49 #include "xattr.h"
  50 #include "acl.h"
  51
  52 static const struct inode_operations v9fs_dir_inode_operations;
  53 static const struct inode_operations v9fs_dir_inode_operations_dotu;
  54 static const struct inode_operations v9fs_file_inode_operations;
  55 static const struct inode_operations v9fs_symlink_inode_operations;
  56
  57 /**
  58  * unixmode2p9mode - convert unix mode bits to plan 9
  59  * @v9ses: v9fs session information
  60  * @mode: mode to convert
  61  *
  62  */
  63
  64 static u32 unixmode2p9mode(struct v9fs_session_info *v9ses, umode_t mode)
  65 {
  66         int res;
  67         res = mode & 0777;
  68         if (S_ISDIR(mode))
  69                 res |= P9_DMDIR;
  70         if (v9fs_proto_dotu(v9ses)) {
  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         }
  89         return res;
  90 }
  91
  92 /**
  93  * p9mode2perm- convert plan9 mode bits to unix permission bits
  94  * @v9ses: v9fs session information
  95  * @stat: p9_wstat from which mode need to be derived
  96  *
  97  */
  98 static int p9mode2perm(struct v9fs_session_info *v9ses,
  99                        struct p9_wstat *stat)
 100 {
 101         int res;
 102         int mode = stat->mode;
 103
 104         res = mode & S_IALLUGO;
 105         if (v9fs_proto_dotu(v9ses)) {
 106                 if ((mode & P9_DMSETUID) == P9_DMSETUID)
 107                         res |= S_ISUID;
 108
 109                 if ((mode & P9_DMSETGID) == P9_DMSETGID)
 110                         res |= S_ISGID;
 111
 112                 if ((mode & P9_DMSETVTX) == P9_DMSETVTX)
 113                         res |= S_ISVTX;
 114         }
 115         return res;
 116 }
 117
 118 /**
 119  * p9mode2unixmode- convert plan9 mode bits to unix mode bits
 120  * @v9ses: v9fs session information
 121  * @stat: p9_wstat from which mode need to be derived
 122  * @rdev: major number, minor number in case of device files.
 123  *
 124  */
 125 static umode_t p9mode2unixmode(struct v9fs_session_info *v9ses,
 126                                struct p9_wstat *stat, dev_t *rdev)
 127 {
 128         int res;
 129         u32 mode = stat->mode;
 130
 131         *rdev = 0;
 132         res = p9mode2perm(v9ses, stat);
 133
 134         if ((mode & P9_DMDIR) == P9_DMDIR)
 135                 res |= S_IFDIR;
 136         else if ((mode & P9_DMSYMLINK) && (v9fs_proto_dotu(v9ses)))
 137                 res |= S_IFLNK;
 138         else if ((mode & P9_DMSOCKET) && (v9fs_proto_dotu(v9ses))
 139                  && (v9ses->nodev == 0))
 140                 res |= S_IFSOCK;
 141         else if ((mode & P9_DMNAMEDPIPE) && (v9fs_proto_dotu(v9ses))
 142                  && (v9ses->nodev == 0))
 143                 res |= S_IFIFO;
 144         else if ((mode & P9_DMDEVICE) && (v9fs_proto_dotu(v9ses))
 145                  && (v9ses->nodev == 0)) {
 146                 char type = 0, ext[32];
 147                 int major = -1, minor = -1;
 148
 149                 strlcpy(ext, stat->extension, sizeof(ext));
 150                 sscanf(ext, "%c %i %i", &type, &major, &minor);
 151                 switch (type) {
 152                 case 'c':
 153                         res |= S_IFCHR;
 154                         break;
 155                 case 'b':
 156                         res |= S_IFBLK;
 157                         break;
 158                 default:
 159                         p9_debug(P9_DEBUG_ERROR, "Unknown special type %c %s\n",
 160                                  type, stat->extension);
 161                 };
 162                 *rdev = MKDEV(major, minor);
 163         } else
 164                 res |= S_IFREG;
 165
 166         return res;
 167 }
 168
 169 /**
 170  * v9fs_uflags2omode- convert posix open flags to plan 9 mode bits
 171  * @uflags: flags to convert
 172  * @extended: if .u extensions are active
 173  */
 174
 175 int v9fs_uflags2omode(int uflags, int extended)
 176 {
 177         int ret;
 178
 179         ret = 0;
 180         switch (uflags&3) {
 181         default:
 182         case O_RDONLY:
 183                 ret = P9_OREAD;
 184                 break;
 185
 186         case O_WRONLY:
 187                 ret = P9_OWRITE;
 188                 break;
 189
 190         case O_RDWR:
 191                 ret = P9_ORDWR;
 192                 break;
 193         }
 194
 195         if (extended) {
 196                 if (uflags & O_EXCL)
 197                         ret |= P9_OEXCL;
 198
 199                 if (uflags & O_APPEND)
 200                         ret |= P9_OAPPEND;
 201         }
 202
 203         return ret;
 204 }
 205
 206 /**
 207  * v9fs_blank_wstat - helper function to setup a 9P stat structure
 208  * @wstat: structure to initialize
 209  *
 210  */
 211
 212 void
 213 v9fs_blank_wstat(struct p9_wstat *wstat)
 214 {
 215         wstat->type = ~0;
 216         wstat->dev = ~0;
 217         wstat->qid.type = ~0;
 218         wstat->qid.version = ~0;
 219         *((long long *)&wstat->qid.path) = ~0;
 220         wstat->mode = ~0;
 221         wstat->atime = ~0;
 222         wstat->mtime = ~0;
 223         wstat->length = ~0;
 224         wstat->name = NULL;
 225         wstat->uid = NULL;
 226         wstat->gid = NULL;
 227         wstat->muid = NULL;
 228         wstat->n_uid = INVALID_UID;
 229         wstat->n_gid = INVALID_GID;
 230         wstat->n_muid = INVALID_UID;
 231         wstat->extension = NULL;
 232 }
 233
 234 /**
 235  * v9fs_alloc_inode - helper function to allocate an inode
 236  *
 237  */
 238 struct inode *v9fs_alloc_inode(struct super_block *sb)
 239 {
 240         struct v9fs_inode *v9inode;
 241         v9inode = (struct v9fs_inode *)kmem_cache_alloc(v9fs_inode_cache,
 242                                                         GFP_KERNEL);
 243         if (!v9inode)
 244                 return NULL;
 245 #ifdef CONFIG_9P_FSCACHE
 246         v9inode->fscache = NULL;
 247         mutex_init(&v9inode->fscache_lock);
 248 #endif
 249         v9inode->writeback_fid = NULL;
 250         v9inode->cache_validity = 0;
 251         mutex_init(&v9inode->v_mutex);
 252         return &v9inode->vfs_inode;
 253 }
 254
 255 /**
 256  * v9fs_destroy_inode - destroy an inode
 257  *
 258  */
 259
 260 static void v9fs_i_callback(struct rcu_head *head)
 261 {
 262         struct inode *inode = container_of(head, struct inode, i_rcu);
 263         kmem_cache_free(v9fs_inode_cache, V9FS_I(inode));
 264 }
 265
 266 void v9fs_destroy_inode(struct inode *inode)
 267 {
 268         call_rcu(&inode->i_rcu, v9fs_i_callback);
 269 }
 270
 271 int v9fs_init_inode(struct v9fs_session_info *v9ses,
 272                     struct inode *inode, umode_t mode, dev_t rdev)
 273 {
 274         int err = 0;
 275
 276         inode_init_owner(inode, NULL, mode);
 277         inode->i_blocks = 0;
 278         inode->i_rdev = rdev;
 279         inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
 280         inode->i_mapping->a_ops = &v9fs_addr_operations;
 281
 282         switch (mode & S_IFMT) {
 283         case S_IFIFO:
 284         case S_IFBLK:
 285         case S_IFCHR:
 286         case S_IFSOCK:
 287                 if (v9fs_proto_dotl(v9ses)) {
 288                         inode->i_op = &v9fs_file_inode_operations_dotl;
 289                 } else if (v9fs_proto_dotu(v9ses)) {
 290                         inode->i_op = &v9fs_file_inode_operations;
 291                 } else {
 292                         p9_debug(P9_DEBUG_ERROR,
 293                                  "special files without extended mode\n");
 294                         err = -EINVAL;
 295                         goto error;
 296                 }
 297                 init_special_inode(inode, inode->i_mode, inode->i_rdev);
 298                 break;
 299         case S_IFREG:
 300                 if (v9fs_proto_dotl(v9ses)) {
 301                         inode->i_op = &v9fs_file_inode_operations_dotl;
 302                         if (v9ses->cache == CACHE_LOOSE ||
 303                             v9ses->cache == CACHE_FSCACHE)
 304                                 inode->i_fop =
 305                                         &v9fs_cached_file_operations_dotl;
 306                         else if (v9ses->cache == CACHE_MMAP)
 307                                 inode->i_fop = &v9fs_mmap_file_operations_dotl;
 308                         else
 309                                 inode->i_fop = &v9fs_file_operations_dotl;
 310                 } else {
 311                         inode->i_op = &v9fs_file_inode_operations;
 312                         if (v9ses->cache == CACHE_LOOSE ||
 313                             v9ses->cache == CACHE_FSCACHE)
 314                                 inode->i_fop =
 315                                         &v9fs_cached_file_operations;
 316                         else if (v9ses->cache == CACHE_MMAP)
 317                                 inode->i_fop = &v9fs_mmap_file_operations;
 318                         else
 319                                 inode->i_fop = &v9fs_file_operations;
 320                 }
 321
 322                 break;
 323         case S_IFLNK:
 324                 if (!v9fs_proto_dotu(v9ses) && !v9fs_proto_dotl(v9ses)) {
 325                         p9_debug(P9_DEBUG_ERROR,
 326                                  "extended modes used with legacy protocol\n");
 327                         err = -EINVAL;
 328                         goto error;
 329                 }
 330
 331                 if (v9fs_proto_dotl(v9ses))
 332                         inode->i_op = &v9fs_symlink_inode_operations_dotl;
 333                 else
 334                         inode->i_op = &v9fs_symlink_inode_operations;
 335
 336                 break;
 337         case S_IFDIR:
 338                 inc_nlink(inode);
 339                 if (v9fs_proto_dotl(v9ses))
 340                         inode->i_op = &v9fs_dir_inode_operations_dotl;
 341                 else if (v9fs_proto_dotu(v9ses))
 342                         inode->i_op = &v9fs_dir_inode_operations_dotu;
 343                 else
 344                         inode->i_op = &v9fs_dir_inode_operations;
 345
 346                 if (v9fs_proto_dotl(v9ses))
 347                         inode->i_fop = &v9fs_dir_operations_dotl;
 348                 else
 349                         inode->i_fop = &v9fs_dir_operations;
 350
 351                 break;
 352         default:
 353                 p9_debug(P9_DEBUG_ERROR, "BAD mode 0x%hx S_IFMT 0x%x\n",
 354                          mode, mode & S_IFMT);
 355                 err = -EINVAL;
 356                 goto error;
 357         }
 358 error:
 359         return err;
 360
 361 }
 362
 363 /**
 364  * v9fs_get_inode - helper function to setup an inode
 365  * @sb: superblock
 366  * @mode: mode to setup inode with
 367  *
 368  */
 369
 370 struct inode *v9fs_get_inode(struct super_block *sb, umode_t mode, dev_t rdev)
 371 {
 372         int err;
 373         struct inode *inode;
 374         struct v9fs_session_info *v9ses = sb->s_fs_info;
 375
 376         p9_debug(P9_DEBUG_VFS, "super block: %p mode: %ho\n", sb, mode);
 377
 378         inode = new_inode(sb);
 379         if (!inode) {
 380                 pr_warn("%s (%d): Problem allocating inode\n",
 381                         __func__, task_pid_nr(current));
 382                 return ERR_PTR(-ENOMEM);
 383         }
 384         err = v9fs_init_inode(v9ses, inode, mode, rdev);
 385         if (err) {
 386                 iput(inode);
 387                 return ERR_PTR(err);
 388         }
 389         return inode;
 390 }
 391
 392 /*
 393 static struct v9fs_fid*
 394 v9fs_clone_walk(struct v9fs_session_info *v9ses, u32 fid, struct dentry *dentry)
 395 {
 396         int err;
 397         int nfid;
 398         struct v9fs_fid *ret;
 399         struct v9fs_fcall *fcall;
 400
 401         nfid = v9fs_get_idpool(&v9ses->fidpool);
 402         if (nfid < 0) {
 403                 eprintk(KERN_WARNING, "no free fids available\n");
 404                 return ERR_PTR(-ENOSPC);
 405         }
 406
 407         err = v9fs_t_walk(v9ses, fid, nfid, (char *) dentry->d_name.name,
 408                 &fcall);
 409
 410         if (err < 0) {
 411                 if (fcall && fcall->id == RWALK)
 412                         goto clunk_fid;
 413
 414                 PRINT_FCALL_ERROR("walk error", fcall);
 415                 v9fs_put_idpool(nfid, &v9ses->fidpool);
 416                 goto error;
 417         }
 418
 419         kfree(fcall);
 420         fcall = NULL;
 421         ret = v9fs_fid_create(v9ses, nfid);
 422         if (!ret) {
 423                 err = -ENOMEM;
 424                 goto clunk_fid;
 425         }
 426
 427         err = v9fs_fid_insert(ret, dentry);
 428         if (err < 0) {
 429                 v9fs_fid_destroy(ret);
 430                 goto clunk_fid;
 431         }
 432
 433         return ret;
 434
 435 clunk_fid:
 436         v9fs_t_clunk(v9ses, nfid);
 437
 438 error:
 439         kfree(fcall);
 440         return ERR_PTR(err);
 441 }
 442 */
 443
 444
 445 /**
 446  * v9fs_clear_inode - release an inode
 447  * @inode: inode to release
 448  *
 449  */
 450 void v9fs_evict_inode(struct inode *inode)
 451 {
 452         struct v9fs_inode *v9inode = V9FS_I(inode);
 453
 454         truncate_inode_pages_final(&inode->i_data);
 455         clear_inode(inode);
 456         filemap_fdatawrite(&inode->i_data);
 457
 458         v9fs_cache_inode_put_cookie(inode);
 459         /* clunk the fid stashed in writeback_fid */
 460         if (v9inode->writeback_fid) {
 461                 p9_client_clunk(v9inode->writeback_fid);
 462                 v9inode->writeback_fid = NULL;
 463         }
 464 }
 465
 466 static int v9fs_test_inode(struct inode *inode, void *data)
 467 {
 468         int umode;
 469         dev_t rdev;
 470         struct v9fs_inode *v9inode = V9FS_I(inode);
 471         struct p9_wstat *st = (struct p9_wstat *)data;
 472         struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
 473
 474         umode = p9mode2unixmode(v9ses, st, &rdev);
 475         /* don't match inode of different type */
 476         if ((inode->i_mode & S_IFMT) != (umode & S_IFMT))
 477                 return 0;
 478
 479         /* compare qid details */
 480         if (memcmp(&v9inode->qid.version,
 481                    &st->qid.version, sizeof(v9inode->qid.version)))
 482                 return 0;
 483
 484         if (v9inode->qid.type != st->qid.type)
 485                 return 0;
 486
 487         if (v9inode->qid.path != st->qid.path)
 488                 return 0;
 489         return 1;
 490 }
 491
 492 static int v9fs_test_new_inode(struct inode *inode, void *data)
 493 {
 494         return 0;
 495 }
 496
 497 static int v9fs_set_inode(struct inode *inode,  void *data)
 498 {
 499         struct v9fs_inode *v9inode = V9FS_I(inode);
 500         struct p9_wstat *st = (struct p9_wstat *)data;
 501
 502         memcpy(&v9inode->qid, &st->qid, sizeof(st->qid));
 503         return 0;
 504 }
 505
 506 static struct inode *v9fs_qid_iget(struct super_block *sb,
 507                                    struct p9_qid *qid,
 508                                    struct p9_wstat *st,
 509                                    int new)
 510 {
 511         dev_t rdev;
 512         int retval;
 513         umode_t umode;
 514         unsigned long i_ino;
 515         struct inode *inode;
 516         struct v9fs_session_info *v9ses = sb->s_fs_info;
 517         int (*test)(struct inode *, void *);
 518
 519         if (new)
 520                 test = v9fs_test_new_inode;
 521         else
 522                 test = v9fs_test_inode;
 523
 524         i_ino = v9fs_qid2ino(qid);
 525         inode = iget5_locked(sb, i_ino, test, v9fs_set_inode, st);
 526         if (!inode)
 527                 return ERR_PTR(-ENOMEM);
 528         if (!(inode->i_state & I_NEW))
 529                 return inode;
 530         /*
 531          * initialize the inode with the stat info
 532          * FIXME!! we may need support for stale inodes
 533          * later.
 534          */
 535         inode->i_ino = i_ino;
 536         umode = p9mode2unixmode(v9ses, st, &rdev);
 537         retval = v9fs_init_inode(v9ses, inode, umode, rdev);
 538         if (retval)
 539                 goto error;
 540
 541         v9fs_stat2inode(st, inode, sb, 0);
 542         v9fs_cache_inode_get_cookie(inode);
 543         unlock_new_inode(inode);
 544         return inode;
 545 error:
 546         iget_failed(inode);
 547         return ERR_PTR(retval);
 548
 549 }
 550
 551 struct inode *
 552 v9fs_inode_from_fid(struct v9fs_session_info *v9ses, struct p9_fid *fid,
 553                     struct super_block *sb, int new)
 554 {
 555         struct p9_wstat *st;
 556         struct inode *inode = NULL;
 557
 558         st = p9_client_stat(fid);
 559         if (IS_ERR(st))
 560                 return ERR_CAST(st);
 561
 562         inode = v9fs_qid_iget(sb, &st->qid, st, new);
 563         p9stat_free(st);
 564         kfree(st);
 565         return inode;
 566 }
 567
 568 /**
 569  * v9fs_at_to_dotl_flags- convert Linux specific AT flags to
 570  * plan 9 AT flag.
 571  * @flags: flags to convert
 572  */
 573 static int v9fs_at_to_dotl_flags(int flags)
 574 {
 575         int rflags = 0;
 576         if (flags & AT_REMOVEDIR)
 577                 rflags |= P9_DOTL_AT_REMOVEDIR;
 578         return rflags;
 579 }
 580
 581 /**
 582  * v9fs_remove - helper function to remove files and directories
 583  * @dir: directory inode that is being deleted
 584  * @dentry:  dentry that is being deleted
 585  * @flags: removing a directory
 586  *
 587  */
 588
 589 static int v9fs_remove(struct inode *dir, struct dentry *dentry, int flags)
 590 {
 591         struct inode *inode;
 592         int retval = -EOPNOTSUPP;
 593         struct p9_fid *v9fid, *dfid;
 594         struct v9fs_session_info *v9ses;
 595
 596         p9_debug(P9_DEBUG_VFS, "inode: %p dentry: %p rmdir: %x\n",
 597                  dir, dentry, flags);
 598
 599         v9ses = v9fs_inode2v9ses(dir);
 600         inode = d_inode(dentry);
 601         dfid = v9fs_parent_fid(dentry);
 602         if (IS_ERR(dfid)) {
 603                 retval = PTR_ERR(dfid);
 604                 p9_debug(P9_DEBUG_VFS, "fid lookup failed %d\n", retval);
 605                 return retval;
 606         }
 607         if (v9fs_proto_dotl(v9ses))
 608                 retval = p9_client_unlinkat(dfid, dentry->d_name.name,
 609                                             v9fs_at_to_dotl_flags(flags));
 610         if (retval == -EOPNOTSUPP) {
 611                 /* Try the one based on path */
 612                 v9fid = v9fs_fid_clone(dentry);
 613                 if (IS_ERR(v9fid))
 614                         return PTR_ERR(v9fid);
 615                 retval = p9_client_remove(v9fid);
 616         }
 617         if (!retval) {
 618                 /*
 619                  * directories on unlink should have zero
 620                  * link count
 621                  */
 622                 if (flags & AT_REMOVEDIR) {
 623                         clear_nlink(inode);
 624                         drop_nlink(dir);
 625                 } else
 626                         drop_nlink(inode);
 627
 628                 v9fs_invalidate_inode_attr(inode);
 629                 v9fs_invalidate_inode_attr(dir);
 630         }
 631         return retval;
 632 }
 633
 634 /**
 635  * v9fs_create - Create a file
 636  * @v9ses: session information
 637  * @dir: directory that dentry is being created in
 638  * @dentry:  dentry that is being created
 639  * @extension: 9p2000.u extension string to support devices, etc.
 640  * @perm: create permissions
 641  * @mode: open mode
 642  *
 643  */
 644 static struct p9_fid *
 645 v9fs_create(struct v9fs_session_info *v9ses, struct inode *dir,
 646                 struct dentry *dentry, char *extension, u32 perm, u8 mode)
 647 {
 648         int err;
 649         char *name;
 650         struct p9_fid *dfid, *ofid, *fid;
 651         struct inode *inode;
 652
 653         p9_debug(P9_DEBUG_VFS, "name %pd\n", dentry);
 654
 655         err = 0;
 656         ofid = NULL;
 657         fid = NULL;
 658         name = (char *) dentry->d_name.name;
 659         dfid = v9fs_parent_fid(dentry);
 660         if (IS_ERR(dfid)) {
 661                 err = PTR_ERR(dfid);
 662                 p9_debug(P9_DEBUG_VFS, "fid lookup failed %d\n", err);
 663                 return ERR_PTR(err);
 664         }
 665
 666         /* clone a fid to use for creation */
 667         ofid = clone_fid(dfid);
 668         if (IS_ERR(ofid)) {
 669                 err = PTR_ERR(ofid);
 670                 p9_debug(P9_DEBUG_VFS, "p9_client_walk failed %d\n", err);
 671                 return ERR_PTR(err);
 672         }
 673
 674         err = p9_client_fcreate(ofid, name, perm, mode, extension);
 675         if (err < 0) {
 676                 p9_debug(P9_DEBUG_VFS, "p9_client_fcreate failed %d\n", err);
 677                 goto error;
 678         }
 679
 680         if (!(perm & P9_DMLINK)) {
 681                 /* now walk from the parent so we can get unopened fid */
 682                 fid = p9_client_walk(dfid, 1, &name, 1);
 683                 if (IS_ERR(fid)) {
 684                         err = PTR_ERR(fid);
 685                         p9_debug(P9_DEBUG_VFS,
 686                                    "p9_client_walk failed %d\n", err);
 687                         fid = NULL;
 688                         goto error;
 689                 }
 690                 /*
 691                  * instantiate inode and assign the unopened fid to the dentry
 692                  */
 693                 inode = v9fs_get_new_inode_from_fid(v9ses, fid, dir->i_sb);
 694                 if (IS_ERR(inode)) {
 695                         err = PTR_ERR(inode);
 696                         p9_debug(P9_DEBUG_VFS,
 697                                    "inode creation failed %d\n", err);
 698                         goto error;
 699                 }
 700                 v9fs_fid_add(dentry, fid);
 701                 d_instantiate(dentry, inode);
 702         }
 703         return ofid;
 704 error:
 705         if (ofid)
 706                 p9_client_clunk(ofid);
 707
 708         if (fid)
 709                 p9_client_clunk(fid);
 710
 711         return ERR_PTR(err);
 712 }
 713
 714 /**
 715  * v9fs_vfs_create - VFS hook to create a regular file
 716  *
 717  * open(.., O_CREAT) is handled in v9fs_vfs_atomic_open().  This is only called
 718  * for mknod(2).
 719  *
 720  * @dir: directory inode that is being created
 721  * @dentry:  dentry that is being deleted
 722  * @mode: create permissions
 723  *
 724  */
 725
 726 static int
 727 v9fs_vfs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
 728                 bool excl)
 729 {
 730         struct v9fs_session_info *v9ses = v9fs_inode2v9ses(dir);
 731         u32 perm = unixmode2p9mode(v9ses, mode);
 732         struct p9_fid *fid;
 733
 734         /* P9_OEXCL? */
 735         fid = v9fs_create(v9ses, dir, dentry, NULL, perm, P9_ORDWR);
 736         if (IS_ERR(fid))
 737                 return PTR_ERR(fid);
 738
 739         v9fs_invalidate_inode_attr(dir);
 740         p9_client_clunk(fid);
 741
 742         return 0;
 743 }
 744
 745 /**
 746  * v9fs_vfs_mkdir - VFS mkdir hook to create a directory
 747  * @dir:  inode that is being unlinked
 748  * @dentry: dentry that is being unlinked
 749  * @mode: mode for new directory
 750  *
 751  */
 752
 753 static int v9fs_vfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 754 {
 755         int err;
 756         u32 perm;
 757         struct p9_fid *fid;
 758         struct v9fs_session_info *v9ses;
 759
 760         p9_debug(P9_DEBUG_VFS, "name %pd\n", dentry);
 761         err = 0;
 762         v9ses = v9fs_inode2v9ses(dir);
 763         perm = unixmode2p9mode(v9ses, mode | S_IFDIR);
 764         fid = v9fs_create(v9ses, dir, dentry, NULL, perm, P9_OREAD);
 765         if (IS_ERR(fid)) {
 766                 err = PTR_ERR(fid);
 767                 fid = NULL;
 768         } else {
 769                 inc_nlink(dir);
 770                 v9fs_invalidate_inode_attr(dir);
 771         }
 772
 773         if (fid)
 774                 p9_client_clunk(fid);
 775
 776         return err;
 777 }
 778
 779 /**
 780  * v9fs_vfs_lookup - VFS lookup hook to "walk" to a new inode
 781  * @dir:  inode that is being walked from
 782  * @dentry: dentry that is being walked to?
 783  * @flags: lookup flags (unused)
 784  *
 785  */
 786
 787 struct dentry *v9fs_vfs_lookup(struct inode *dir, struct dentry *dentry,
 788                                       unsigned int flags)
 789 {
 790         struct dentry *res;
 791         struct v9fs_session_info *v9ses;
 792         struct p9_fid *dfid, *fid;
 793         struct inode *inode;
 794         char *name;
 795
 796         p9_debug(P9_DEBUG_VFS, "dir: %p dentry: (%pd) %p flags: %x\n",
 797                  dir, dentry, dentry, flags);
 798
 799         if (dentry->d_name.len > NAME_MAX)
 800                 return ERR_PTR(-ENAMETOOLONG);
 801
 802         v9ses = v9fs_inode2v9ses(dir);
 803         /* We can walk d_parent because we hold the dir->i_mutex */
 804         dfid = v9fs_parent_fid(dentry);
 805         if (IS_ERR(dfid))
 806                 return ERR_CAST(dfid);
 807
 808         name = (char *) dentry->d_name.name;
 809         fid = p9_client_walk(dfid, 1, &name, 1);
 810         if (IS_ERR(fid)) {
 811                 if (fid == ERR_PTR(-ENOENT)) {
 812                         d_add(dentry, NULL);
 813                         return NULL;
 814                 }
 815                 return ERR_CAST(fid);
 816         }
 817         /*
 818          * Make sure we don't use a wrong inode due to parallel
 819          * unlink. For cached mode create calls request for new
 820          * inode. But with cache disabled, lookup should do this.
 821          */
 822         if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
 823                 inode = v9fs_get_inode_from_fid(v9ses, fid, dir->i_sb);
 824         else
 825                 inode = v9fs_get_new_inode_from_fid(v9ses, fid, dir->i_sb);
 826         if (IS_ERR(inode)) {
 827                 p9_client_clunk(fid);
 828                 return ERR_CAST(inode);
 829         }
 830         /*
 831          * If we had a rename on the server and a parallel lookup
 832          * for the new name, then make sure we instantiate with
 833          * the new name. ie look up for a/b, while on server somebody
 834          * moved b under k and client parallely did a lookup for
 835          * k/b.
 836          */
 837         res = d_splice_alias(inode, dentry);
 838         if (!res)
 839                 v9fs_fid_add(dentry, fid);
 840         else if (!IS_ERR(res))
 841                 v9fs_fid_add(res, fid);
 842         else
 843                 p9_client_clunk(fid);
 844         return res;
 845 }
 846
 847 static int
 848 v9fs_vfs_atomic_open(struct inode *dir, struct dentry *dentry,
 849                      struct file *file, unsigned flags, umode_t mode,
 850                      int *opened)
 851 {
 852         int err;
 853         u32 perm;
 854         struct v9fs_inode *v9inode;
 855         struct v9fs_session_info *v9ses;
 856         struct p9_fid *fid, *inode_fid;
 857         struct dentry *res = NULL;
 858
 859         if (d_in_lookup(dentry)) {
 860                 res = v9fs_vfs_lookup(dir, dentry, 0);
 861                 if (IS_ERR(res))
 862                         return PTR_ERR(res);
 863
 864                 if (res)
 865                         dentry = res;
 866         }
 867
 868         /* Only creates */
 869         if (!(flags & O_CREAT) || d_really_is_positive(dentry))
 870                 return finish_no_open(file, res);
 871
 872         err = 0;
 873
 874         v9ses = v9fs_inode2v9ses(dir);
 875         perm = unixmode2p9mode(v9ses, mode);
 876         fid = v9fs_create(v9ses, dir, dentry, NULL, perm,
 877                                 v9fs_uflags2omode(flags,
 878                                                 v9fs_proto_dotu(v9ses)));
 879         if (IS_ERR(fid)) {
 880                 err = PTR_ERR(fid);
 881                 fid = NULL;
 882                 goto error;
 883         }
 884
 885         v9fs_invalidate_inode_attr(dir);
 886         v9inode = V9FS_I(d_inode(dentry));
 887         mutex_lock(&v9inode->v_mutex);
 888         if ((v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE) &&
 889             !v9inode->writeback_fid &&
 890             ((flags & O_ACCMODE) != O_RDONLY)) {
 891                 /*
 892                  * clone a fid and add it to writeback_fid
 893                  * we do it during open time instead of
 894                  * page dirty time via write_begin/page_mkwrite
 895                  * because we want write after unlink usecase
 896                  * to work.
 897                  */
 898                 inode_fid = v9fs_writeback_fid(dentry);
 899                 if (IS_ERR(inode_fid)) {
 900                         err = PTR_ERR(inode_fid);
 901                         mutex_unlock(&v9inode->v_mutex);
 902                         goto error;
 903                 }
 904                 v9inode->writeback_fid = (void *) inode_fid;
 905         }
 906         mutex_unlock(&v9inode->v_mutex);
 907         err = finish_open(file, dentry, generic_file_open, opened);
 908         if (err)
 909                 goto error;
 910
 911         file->private_data = fid;
 912         if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
 913                 v9fs_cache_inode_set_cookie(d_inode(dentry), file);
 914
 915         *opened |= FILE_CREATED;
 916 out:
 917         dput(res);
 918         return err;
 919
 920 error:
 921         if (fid)
 922                 p9_client_clunk(fid);
 923         goto out;
 924 }
 925
 926 /**
 927  * v9fs_vfs_unlink - VFS unlink hook to delete an inode
 928  * @i:  inode that is being unlinked
 929  * @d: dentry that is being unlinked
 930  *
 931  */
 932
 933 int v9fs_vfs_unlink(struct inode *i, struct dentry *d)
 934 {
 935         return v9fs_remove(i, d, 0);
 936 }
 937
 938 /**
 939  * v9fs_vfs_rmdir - VFS unlink hook to delete a directory
 940  * @i:  inode that is being unlinked
 941  * @d: dentry that is being unlinked
 942  *
 943  */
 944
 945 int v9fs_vfs_rmdir(struct inode *i, struct dentry *d)
 946 {
 947         return v9fs_remove(i, d, AT_REMOVEDIR);
 948 }
 949
 950 /**
 951  * v9fs_vfs_rename - VFS hook to rename an inode
 952  * @old_dir:  old dir inode
 953  * @old_dentry: old dentry
 954  * @new_dir: new dir inode
 955  * @new_dentry: new dentry
 956  *
 957  */
 958
 959 int
 960 v9fs_vfs_rename(struct inode *old_dir, struct dentry *old_dentry,
 961                 struct inode *new_dir, struct dentry *new_dentry,
 962                 unsigned int flags)
 963 {
 964         int retval;
 965         struct inode *old_inode;
 966         struct inode *new_inode;
 967         struct v9fs_session_info *v9ses;
 968         struct p9_fid *oldfid;
 969         struct p9_fid *olddirfid;
 970         struct p9_fid *newdirfid;
 971         struct p9_wstat wstat;
 972
 973         if (flags)
 974                 return -EINVAL;
 975
 976         p9_debug(P9_DEBUG_VFS, "\n");
 977         retval = 0;
 978         old_inode = d_inode(old_dentry);
 979         new_inode = d_inode(new_dentry);
 980         v9ses = v9fs_inode2v9ses(old_inode);
 981         oldfid = v9fs_fid_lookup(old_dentry);
 982         if (IS_ERR(oldfid))
 983                 return PTR_ERR(oldfid);
 984
 985         olddirfid = clone_fid(v9fs_parent_fid(old_dentry));
 986         if (IS_ERR(olddirfid)) {
 987                 retval = PTR_ERR(olddirfid);
 988                 goto done;
 989         }
 990
 991         newdirfid = clone_fid(v9fs_parent_fid(new_dentry));
 992         if (IS_ERR(newdirfid)) {
 993                 retval = PTR_ERR(newdirfid);
 994                 goto clunk_olddir;
 995         }
 996
 997         down_write(&v9ses->rename_sem);
 998         if (v9fs_proto_dotl(v9ses)) {
 999                 retval = p9_client_renameat(olddirfid, old_dentry->d_name.name,
1000                                             newdirfid, new_dentry->d_name.name);
1001                 if (retval == -EOPNOTSUPP)
1002                         retval = p9_client_rename(oldfid, newdirfid,
1003                                                   new_dentry->d_name.name);
1004                 if (retval != -EOPNOTSUPP)
1005                         goto clunk_newdir;
1006         }
1007         if (old_dentry->d_parent != new_dentry->d_parent) {
1008                 /*
1009                  * 9P .u can only handle file rename in the same directory
1010                  */
1011
1012                 p9_debug(P9_DEBUG_ERROR, "old dir and new dir are different\n");
1013                 retval = -EXDEV;
1014                 goto clunk_newdir;
1015         }
1016         v9fs_blank_wstat(&wstat);
1017         wstat.muid = v9ses->uname;
1018         wstat.name = (char *) new_dentry->d_name.name;
1019         retval = p9_client_wstat(oldfid, &wstat);
1020
1021 clunk_newdir:
1022         if (!retval) {
1023                 if (new_inode) {
1024                         if (S_ISDIR(new_inode->i_mode))
1025                                 clear_nlink(new_inode);
1026                         else
1027                                 drop_nlink(new_inode);
1028                 }
1029                 if (S_ISDIR(old_inode->i_mode)) {
1030                         if (!new_inode)
1031                                 inc_nlink(new_dir);
1032                         drop_nlink(old_dir);
1033                 }
1034                 v9fs_invalidate_inode_attr(old_inode);
1035                 v9fs_invalidate_inode_attr(old_dir);
1036                 v9fs_invalidate_inode_attr(new_dir);
1037
1038                 /* successful rename */
1039                 d_move(old_dentry, new_dentry);
1040         }
1041         up_write(&v9ses->rename_sem);
1042         p9_client_clunk(newdirfid);
1043
1044 clunk_olddir:
1045         p9_client_clunk(olddirfid);
1046
1047 done:
1048         return retval;
1049 }
1050
1051 /**
1052  * v9fs_vfs_getattr - retrieve file metadata
1053  * @mnt: mount information
1054  * @dentry: file to get attributes on
1055  * @stat: metadata structure to populate
1056  *
1057  */
1058
1059 static int
1060 v9fs_vfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
1061                  struct kstat *stat)
1062 {
1063         struct v9fs_session_info *v9ses;
1064         struct p9_fid *fid;
1065         struct p9_wstat *st;
1066
1067         p9_debug(P9_DEBUG_VFS, "dentry: %p\n", dentry);
1068         v9ses = v9fs_dentry2v9ses(dentry);
1069         if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE) {
1070                 generic_fillattr(d_inode(dentry), stat);
1071                 return 0;
1072         }
1073         fid = v9fs_fid_lookup(dentry);
1074         if (IS_ERR(fid))
1075                 return PTR_ERR(fid);
1076
1077         st = p9_client_stat(fid);
1078         if (IS_ERR(st))
1079                 return PTR_ERR(st);
1080
1081         v9fs_stat2inode(st, d_inode(dentry), dentry->d_sb, 0);
1082         generic_fillattr(d_inode(dentry), stat);
1083
1084         p9stat_free(st);
1085         kfree(st);
1086         return 0;
1087 }
1088
1089 /**
1090  * v9fs_vfs_setattr - set file metadata
1091  * @dentry: file whose metadata to set
1092  * @iattr: metadata assignment structure
1093  *
1094  */
1095
1096 static int v9fs_vfs_setattr(struct dentry *dentry, struct iattr *iattr)
1097 {
1098         int retval;
1099         struct v9fs_session_info *v9ses;
1100         struct p9_fid *fid;
1101         struct p9_wstat wstat;
1102
1103         p9_debug(P9_DEBUG_VFS, "\n");
1104         retval = setattr_prepare(dentry, iattr);
1105         if (retval)
1106                 return retval;
1107
1108         retval = -EPERM;
1109         v9ses = v9fs_dentry2v9ses(dentry);
1110         fid = v9fs_fid_lookup(dentry);
1111         if(IS_ERR(fid))
1112                 return PTR_ERR(fid);
1113
1114         v9fs_blank_wstat(&wstat);
1115         if (iattr->ia_valid & ATTR_MODE)
1116                 wstat.mode = unixmode2p9mode(v9ses, iattr->ia_mode);
1117
1118         if (iattr->ia_valid & ATTR_MTIME)
1119                 wstat.mtime = iattr->ia_mtime.tv_sec;
1120
1121         if (iattr->ia_valid & ATTR_ATIME)
1122                 wstat.atime = iattr->ia_atime.tv_sec;
1123
1124         if (iattr->ia_valid & ATTR_SIZE)
1125                 wstat.length = iattr->ia_size;
1126
1127         if (v9fs_proto_dotu(v9ses)) {
1128                 if (iattr->ia_valid & ATTR_UID)
1129                         wstat.n_uid = iattr->ia_uid;
1130
1131                 if (iattr->ia_valid & ATTR_GID)
1132                         wstat.n_gid = iattr->ia_gid;
1133         }
1134
1135         /* Write all dirty data */
1136         if (d_is_reg(dentry))
1137                 filemap_write_and_wait(d_inode(dentry)->i_mapping);
1138
1139         retval = p9_client_wstat(fid, &wstat);
1140         if (retval < 0)
1141                 return retval;
1142
1143         if ((iattr->ia_valid & ATTR_SIZE) &&
1144             iattr->ia_size != i_size_read(d_inode(dentry)))
1145                 truncate_setsize(d_inode(dentry), iattr->ia_size);
1146
1147         v9fs_invalidate_inode_attr(d_inode(dentry));
1148
1149         setattr_copy(d_inode(dentry), iattr);
1150         mark_inode_dirty(d_inode(dentry));
1151         return 0;
1152 }
1153
1154 /**
1155  * v9fs_stat2inode - populate an inode structure with mistat info
1156  * @stat: Plan 9 metadata (mistat) structure
1157  * @inode: inode to populate
1158  * @sb: superblock of filesystem
1159  * @flags: control flags (e.g. V9FS_STAT2INODE_KEEP_ISIZE)
1160  *
1161  */
1162
1163 void
1164 v9fs_stat2inode(struct p9_wstat *stat, struct inode *inode,
1165                  struct super_block *sb, unsigned int flags)
1166 {
1167         umode_t mode;
1168         char ext[32];
1169         char tag_name[14];
1170         unsigned int i_nlink;
1171         struct v9fs_session_info *v9ses = sb->s_fs_info;
1172         struct v9fs_inode *v9inode = V9FS_I(inode);
1173
1174         set_nlink(inode, 1);
1175
1176         inode->i_atime.tv_sec = stat->atime;
1177         inode->i_mtime.tv_sec = stat->mtime;
1178         inode->i_ctime.tv_sec = stat->mtime;
1179
1180         inode->i_uid = v9ses->dfltuid;
1181         inode->i_gid = v9ses->dfltgid;
1182
1183         if (v9fs_proto_dotu(v9ses)) {
1184                 inode->i_uid = stat->n_uid;
1185                 inode->i_gid = stat->n_gid;
1186         }
1187         if ((S_ISREG(inode->i_mode)) || (S_ISDIR(inode->i_mode))) {
1188                 if (v9fs_proto_dotu(v9ses) && (stat->extension[0] != '\0')) {
1189                         /*
1190                          * Hadlink support got added later to
1191                          * to the .u extension. So there can be
1192                          * server out there that doesn't support
1193                          * this even with .u extension. So check
1194                          * for non NULL stat->extension
1195                          */
1196                         strlcpy(ext, stat->extension, sizeof(ext));
1197                         /* HARDLINKCOUNT %u */
1198                         sscanf(ext, "%13s %u", tag_name, &i_nlink);
1199                         if (!strncmp(tag_name, "HARDLINKCOUNT", 13))
1200                                 set_nlink(inode, i_nlink);
1201                 }
1202         }
1203         mode = p9mode2perm(v9ses, stat);
1204         mode |= inode->i_mode & ~S_IALLUGO;
1205         inode->i_mode = mode;
1206
1207         if (!(flags & V9FS_STAT2INODE_KEEP_ISIZE))
1208                 v9fs_i_size_write(inode, stat->length);
1209         /* not real number of blocks, but 512 byte ones ... */
1210         inode->i_blocks = (stat->length + 512 - 1) >> 9;
1211         v9inode->cache_validity &= ~V9FS_INO_INVALID_ATTR;
1212 }
1213
1214 /**
1215  * v9fs_qid2ino - convert qid into inode number
1216  * @qid: qid to hash
1217  *
1218  * BUG: potential for inode number collisions?
1219  */
1220
1221 ino_t v9fs_qid2ino(struct p9_qid *qid)
1222 {
1223         u64 path = qid->path + 2;
1224         ino_t i = 0;
1225
1226         if (sizeof(ino_t) == sizeof(path))
1227                 memcpy(&i, &path, sizeof(ino_t));
1228         else
1229                 i = (ino_t) (path ^ (path >> 32));
1230
1231         return i;
1232 }
1233
1234 /**
1235  * v9fs_vfs_get_link - follow a symlink path
1236  * @dentry: dentry for symlink
1237  * @inode: inode for symlink
1238  * @done: delayed call for when we are done with the return value
1239  */
1240
1241 static const char *v9fs_vfs_get_link(struct dentry *dentry,
1242                                      struct inode *inode,
1243                                      struct delayed_call *done)
1244 {
1245         struct v9fs_session_info *v9ses;
1246         struct p9_fid *fid;
1247         struct p9_wstat *st;
1248         char *res;
1249
1250         if (!dentry)
1251                 return ERR_PTR(-ECHILD);
1252
1253         v9ses = v9fs_dentry2v9ses(dentry);
1254         fid = v9fs_fid_lookup(dentry);
1255         p9_debug(P9_DEBUG_VFS, "%pd\n", dentry);
1256
1257         if (IS_ERR(fid))
1258                 return ERR_CAST(fid);
1259
1260         if (!v9fs_proto_dotu(v9ses))
1261                 return ERR_PTR(-EBADF);
1262
1263         st = p9_client_stat(fid);
1264         if (IS_ERR(st))
1265                 return ERR_CAST(st);
1266
1267         if (!(st->mode & P9_DMSYMLINK)) {
1268                 p9stat_free(st);
1269                 kfree(st);
1270                 return ERR_PTR(-EINVAL);
1271         }
1272         res = st->extension;
1273         st->extension = NULL;
1274         if (strlen(res) >= PATH_MAX)
1275                 res[PATH_MAX - 1] = '\0';
1276
1277         p9stat_free(st);
1278         kfree(st);
1279         set_delayed_call(done, kfree_link, res);
1280         return res;
1281 }
1282
1283 /**
1284  * v9fs_vfs_mkspecial - create a special file
1285  * @dir: inode to create special file in
1286  * @dentry: dentry to create
1287  * @perm: mode to create special file
1288  * @extension: 9p2000.u format extension string representing special file
1289  *
1290  */
1291
1292 static int v9fs_vfs_mkspecial(struct inode *dir, struct dentry *dentry,
1293         u32 perm, const char *extension)
1294 {
1295         struct p9_fid *fid;
1296         struct v9fs_session_info *v9ses;
1297
1298         v9ses = v9fs_inode2v9ses(dir);
1299         if (!v9fs_proto_dotu(v9ses)) {
1300                 p9_debug(P9_DEBUG_ERROR, "not extended\n");
1301                 return -EPERM;
1302         }
1303
1304         fid = v9fs_create(v9ses, dir, dentry, (char *) extension, perm,
1305                                                                 P9_OREAD);
1306         if (IS_ERR(fid))
1307                 return PTR_ERR(fid);
1308
1309         v9fs_invalidate_inode_attr(dir);
1310         p9_client_clunk(fid);
1311         return 0;
1312 }
1313
1314 /**
1315  * v9fs_vfs_symlink - helper function to create symlinks
1316  * @dir: directory inode containing symlink
1317  * @dentry: dentry for symlink
1318  * @symname: symlink data
1319  *
1320  * See Also: 9P2000.u RFC for more information
1321  *
1322  */
1323
1324 static int
1325 v9fs_vfs_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
1326 {
1327         p9_debug(P9_DEBUG_VFS, " %lu,%pd,%s\n",
1328                  dir->i_ino, dentry, symname);
1329
1330         return v9fs_vfs_mkspecial(dir, dentry, P9_DMSYMLINK, symname);
1331 }
1332
1333 #define U32_MAX_DIGITS 10
1334
1335 /**
1336  * v9fs_vfs_link - create a hardlink
1337  * @old_dentry: dentry for file to link to
1338  * @dir: inode destination for new link
1339  * @dentry: dentry for link
1340  *
1341  */
1342
1343 static int
1344 v9fs_vfs_link(struct dentry *old_dentry, struct inode *dir,
1345               struct dentry *dentry)
1346 {
1347         int retval;
1348         char name[1 + U32_MAX_DIGITS + 2]; /* sign + number + \n + \0 */
1349         struct p9_fid *oldfid;
1350
1351         p9_debug(P9_DEBUG_VFS, " %lu,%pd,%pd\n",
1352                  dir->i_ino, dentry, old_dentry);
1353
1354         oldfid = v9fs_fid_clone(old_dentry);
1355         if (IS_ERR(oldfid))
1356                 return PTR_ERR(oldfid);
1357
1358         sprintf(name, "%d\n", oldfid->fid);
1359         retval = v9fs_vfs_mkspecial(dir, dentry, P9_DMLINK, name);
1360         if (!retval) {
1361                 v9fs_refresh_inode(oldfid, d_inode(old_dentry));
1362                 v9fs_invalidate_inode_attr(dir);
1363         }
1364         p9_client_clunk(oldfid);
1365         return retval;
1366 }
1367
1368 /**
1369  * v9fs_vfs_mknod - create a special file
1370  * @dir: inode destination for new link
1371  * @dentry: dentry for file
1372  * @mode: mode for creation
1373  * @rdev: device associated with special file
1374  *
1375  */
1376
1377 static int
1378 v9fs_vfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t rdev)
1379 {
1380         struct v9fs_session_info *v9ses = v9fs_inode2v9ses(dir);
1381         int retval;
1382         char name[2 + U32_MAX_DIGITS + 1 + U32_MAX_DIGITS + 1];
1383         u32 perm;
1384
1385         p9_debug(P9_DEBUG_VFS, " %lu,%pd mode: %hx MAJOR: %u MINOR: %u\n",
1386                  dir->i_ino, dentry, mode,
1387                  MAJOR(rdev), MINOR(rdev));
1388
1389         /* build extension */
1390         if (S_ISBLK(mode))
1391                 sprintf(name, "b %u %u", MAJOR(rdev), MINOR(rdev));
1392         else if (S_ISCHR(mode))
1393                 sprintf(name, "c %u %u", MAJOR(rdev), MINOR(rdev));
1394         else
1395                 *name = 0;
1396
1397         perm = unixmode2p9mode(v9ses, mode);
1398         retval = v9fs_vfs_mkspecial(dir, dentry, perm, name);
1399
1400         return retval;
1401 }
1402
1403 int v9fs_refresh_inode(struct p9_fid *fid, struct inode *inode)
1404 {
1405         int umode;
1406         dev_t rdev;
1407         struct p9_wstat *st;
1408         struct v9fs_session_info *v9ses;
1409         unsigned int flags;
1410
1411         v9ses = v9fs_inode2v9ses(inode);
1412         st = p9_client_stat(fid);
1413         if (IS_ERR(st))
1414                 return PTR_ERR(st);
1415         /*
1416          * Don't update inode if the file type is different
1417          */
1418         umode = p9mode2unixmode(v9ses, st, &rdev);
1419         if ((inode->i_mode & S_IFMT) != (umode & S_IFMT))
1420                 goto out;
1421
1422         /*
1423          * We don't want to refresh inode->i_size,
1424          * because we may have cached data
1425          */
1426         flags = (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE) ?
1427                 V9FS_STAT2INODE_KEEP_ISIZE : 0;
1428         v9fs_stat2inode(st, inode, inode->i_sb, flags);
1429 out:
1430         p9stat_free(st);
1431         kfree(st);
1432         return 0;
1433 }
1434
1435 static const struct inode_operations v9fs_dir_inode_operations_dotu = {
1436         .create = v9fs_vfs_create,
1437         .lookup = v9fs_vfs_lookup,
1438         .atomic_open = v9fs_vfs_atomic_open,
1439         .symlink = v9fs_vfs_symlink,
1440         .link = v9fs_vfs_link,
1441         .unlink = v9fs_vfs_unlink,
1442         .mkdir = v9fs_vfs_mkdir,
1443         .rmdir = v9fs_vfs_rmdir,
1444         .mknod = v9fs_vfs_mknod,
1445         .rename = v9fs_vfs_rename,
1446         .getattr = v9fs_vfs_getattr,
1447         .setattr = v9fs_vfs_setattr,
1448 };
1449
1450 static const struct inode_operations v9fs_dir_inode_operations = {
1451         .create = v9fs_vfs_create,
1452         .lookup = v9fs_vfs_lookup,
1453         .atomic_open = v9fs_vfs_atomic_open,
1454         .unlink = v9fs_vfs_unlink,
1455         .mkdir = v9fs_vfs_mkdir,
1456         .rmdir = v9fs_vfs_rmdir,
1457         .mknod = v9fs_vfs_mknod,
1458         .rename = v9fs_vfs_rename,
1459         .getattr = v9fs_vfs_getattr,
1460         .setattr = v9fs_vfs_setattr,
1461 };
1462
1463 static const struct inode_operations v9fs_file_inode_operations = {
1464         .getattr = v9fs_vfs_getattr,
1465         .setattr = v9fs_vfs_setattr,
1466 };
1467
1468 static const struct inode_operations v9fs_symlink_inode_operations = {
1469         .readlink = generic_readlink,
1470         .get_link = v9fs_vfs_get_link,
1471         .getattr = v9fs_vfs_getattr,
1472         .setattr = v9fs_vfs_setattr,
1473 };
1474