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         return 1;
 487 }
 488
 489 static int v9fs_test_new_inode(struct inode *inode, void *data)
 490 {
 491         return 0;
 492 }
 493
 494 static int v9fs_set_inode(struct inode *inode,  void *data)
 495 {
 496         struct v9fs_inode *v9inode = V9FS_I(inode);
 497         struct p9_wstat *st = (struct p9_wstat *)data;
 498
 499         memcpy(&v9inode->qid, &st->qid, sizeof(st->qid));
 500         return 0;
 501 }
 502
 503 static struct inode *v9fs_qid_iget(struct super_block *sb,
 504                                    struct p9_qid *qid,
 505                                    struct p9_wstat *st,
 506                                    int new)
 507 {
 508         dev_t rdev;
 509         int retval;
 510         umode_t umode;
 511         unsigned long i_ino;
 512         struct inode *inode;
 513         struct v9fs_session_info *v9ses = sb->s_fs_info;
 514         int (*test)(struct inode *, void *);
 515
 516         if (new)
 517                 test = v9fs_test_new_inode;
 518         else
 519                 test = v9fs_test_inode;
 520
 521         i_ino = v9fs_qid2ino(qid);
 522         inode = iget5_locked(sb, i_ino, test, v9fs_set_inode, st);
 523         if (!inode)
 524                 return ERR_PTR(-ENOMEM);
 525         if (!(inode->i_state & I_NEW))
 526                 return inode;
 527         /*
 528          * initialize the inode with the stat info
 529          * FIXME!! we may need support for stale inodes
 530          * later.
 531          */
 532         inode->i_ino = i_ino;
 533         umode = p9mode2unixmode(v9ses, st, &rdev);
 534         retval = v9fs_init_inode(v9ses, inode, umode, rdev);
 535         if (retval)
 536                 goto error;
 537
 538         v9fs_stat2inode(st, inode, sb);
 539         v9fs_cache_inode_get_cookie(inode);
 540         unlock_new_inode(inode);
 541         return inode;
 542 error:
 543         iget_failed(inode);
 544         return ERR_PTR(retval);
 545
 546 }
 547
 548 struct inode *
 549 v9fs_inode_from_fid(struct v9fs_session_info *v9ses, struct p9_fid *fid,
 550                     struct super_block *sb, int new)
 551 {
 552         struct p9_wstat *st;
 553         struct inode *inode = NULL;
 554
 555         st = p9_client_stat(fid);
 556         if (IS_ERR(st))
 557                 return ERR_CAST(st);
 558
 559         inode = v9fs_qid_iget(sb, &st->qid, st, new);
 560         p9stat_free(st);
 561         kfree(st);
 562         return inode;
 563 }
 564
 565 /**
 566  * v9fs_at_to_dotl_flags- convert Linux specific AT flags to
 567  * plan 9 AT flag.
 568  * @flags: flags to convert
 569  */
 570 static int v9fs_at_to_dotl_flags(int flags)
 571 {
 572         int rflags = 0;
 573         if (flags & AT_REMOVEDIR)
 574                 rflags |= P9_DOTL_AT_REMOVEDIR;
 575         return rflags;
 576 }
 577
 578 /**
 579  * v9fs_remove - helper function to remove files and directories
 580  * @dir: directory inode that is being deleted
 581  * @dentry:  dentry that is being deleted
 582  * @flags: removing a directory
 583  *
 584  */
 585
 586 static int v9fs_remove(struct inode *dir, struct dentry *dentry, int flags)
 587 {
 588         struct inode *inode;
 589         int retval = -EOPNOTSUPP;
 590         struct p9_fid *v9fid, *dfid;
 591         struct v9fs_session_info *v9ses;
 592
 593         p9_debug(P9_DEBUG_VFS, "inode: %p dentry: %p rmdir: %x\n",
 594                  dir, dentry, flags);
 595
 596         v9ses = v9fs_inode2v9ses(dir);
 597         inode = d_inode(dentry);
 598         dfid = v9fs_parent_fid(dentry);
 599         if (IS_ERR(dfid)) {
 600                 retval = PTR_ERR(dfid);
 601                 p9_debug(P9_DEBUG_VFS, "fid lookup failed %d\n", retval);
 602                 return retval;
 603         }
 604         if (v9fs_proto_dotl(v9ses))
 605                 retval = p9_client_unlinkat(dfid, dentry->d_name.name,
 606                                             v9fs_at_to_dotl_flags(flags));
 607         if (retval == -EOPNOTSUPP) {
 608                 /* Try the one based on path */
 609                 v9fid = v9fs_fid_clone(dentry);
 610                 if (IS_ERR(v9fid))
 611                         return PTR_ERR(v9fid);
 612                 retval = p9_client_remove(v9fid);
 613         }
 614         if (!retval) {
 615                 /*
 616                  * directories on unlink should have zero
 617                  * link count
 618                  */
 619                 if (flags & AT_REMOVEDIR) {
 620                         clear_nlink(inode);
 621                         drop_nlink(dir);
 622                 } else
 623                         drop_nlink(inode);
 624
 625                 v9fs_invalidate_inode_attr(inode);
 626                 v9fs_invalidate_inode_attr(dir);
 627         }
 628         return retval;
 629 }
 630
 631 /**
 632  * v9fs_create - Create a file
 633  * @v9ses: session information
 634  * @dir: directory that dentry is being created in
 635  * @dentry:  dentry that is being created
 636  * @extension: 9p2000.u extension string to support devices, etc.
 637  * @perm: create permissions
 638  * @mode: open mode
 639  *
 640  */
 641 static struct p9_fid *
 642 v9fs_create(struct v9fs_session_info *v9ses, struct inode *dir,
 643                 struct dentry *dentry, char *extension, u32 perm, u8 mode)
 644 {
 645         int err;
 646         const unsigned char *name;
 647         struct p9_fid *dfid, *ofid, *fid;
 648         struct inode *inode;
 649
 650         p9_debug(P9_DEBUG_VFS, "name %pd\n", dentry);
 651
 652         err = 0;
 653         ofid = NULL;
 654         fid = NULL;
 655         name = dentry->d_name.name;
 656         dfid = v9fs_parent_fid(dentry);
 657         if (IS_ERR(dfid)) {
 658                 err = PTR_ERR(dfid);
 659                 p9_debug(P9_DEBUG_VFS, "fid lookup failed %d\n", err);
 660                 return ERR_PTR(err);
 661         }
 662
 663         /* clone a fid to use for creation */
 664         ofid = clone_fid(dfid);
 665         if (IS_ERR(ofid)) {
 666                 err = PTR_ERR(ofid);
 667                 p9_debug(P9_DEBUG_VFS, "p9_client_walk failed %d\n", err);
 668                 return ERR_PTR(err);
 669         }
 670
 671         err = p9_client_fcreate(ofid, name, perm, mode, extension);
 672         if (err < 0) {
 673                 p9_debug(P9_DEBUG_VFS, "p9_client_fcreate failed %d\n", err);
 674                 goto error;
 675         }
 676
 677         if (!(perm & P9_DMLINK)) {
 678                 /* now walk from the parent so we can get unopened fid */
 679                 fid = p9_client_walk(dfid, 1, &name, 1);
 680                 if (IS_ERR(fid)) {
 681                         err = PTR_ERR(fid);
 682                         p9_debug(P9_DEBUG_VFS,
 683                                    "p9_client_walk failed %d\n", err);
 684                         fid = NULL;
 685                         goto error;
 686                 }
 687                 /*
 688                  * instantiate inode and assign the unopened fid to the dentry
 689                  */
 690                 inode = v9fs_get_new_inode_from_fid(v9ses, fid, dir->i_sb);
 691                 if (IS_ERR(inode)) {
 692                         err = PTR_ERR(inode);
 693                         p9_debug(P9_DEBUG_VFS,
 694                                    "inode creation failed %d\n", err);
 695                         goto error;
 696                 }
 697                 v9fs_fid_add(dentry, fid);
 698                 d_instantiate(dentry, inode);
 699         }
 700         return ofid;
 701 error:
 702         if (ofid)
 703                 p9_client_clunk(ofid);
 704
 705         if (fid)
 706                 p9_client_clunk(fid);
 707
 708         return ERR_PTR(err);
 709 }
 710
 711 /**
 712  * v9fs_vfs_create - VFS hook to create a regular file
 713  *
 714  * open(.., O_CREAT) is handled in v9fs_vfs_atomic_open().  This is only called
 715  * for mknod(2).
 716  *
 717  * @dir: directory inode that is being created
 718  * @dentry:  dentry that is being deleted
 719  * @mode: create permissions
 720  *
 721  */
 722
 723 static int
 724 v9fs_vfs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
 725                 bool excl)
 726 {
 727         struct v9fs_session_info *v9ses = v9fs_inode2v9ses(dir);
 728         u32 perm = unixmode2p9mode(v9ses, mode);
 729         struct p9_fid *fid;
 730
 731         /* P9_OEXCL? */
 732         fid = v9fs_create(v9ses, dir, dentry, NULL, perm, P9_ORDWR);
 733         if (IS_ERR(fid))
 734                 return PTR_ERR(fid);
 735
 736         v9fs_invalidate_inode_attr(dir);
 737         p9_client_clunk(fid);
 738
 739         return 0;
 740 }
 741
 742 /**
 743  * v9fs_vfs_mkdir - VFS mkdir hook to create a directory
 744  * @dir:  inode that is being unlinked
 745  * @dentry: dentry that is being unlinked
 746  * @mode: mode for new directory
 747  *
 748  */
 749
 750 static int v9fs_vfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 751 {
 752         int err;
 753         u32 perm;
 754         struct p9_fid *fid;
 755         struct v9fs_session_info *v9ses;
 756
 757         p9_debug(P9_DEBUG_VFS, "name %pd\n", dentry);
 758         err = 0;
 759         v9ses = v9fs_inode2v9ses(dir);
 760         perm = unixmode2p9mode(v9ses, mode | S_IFDIR);
 761         fid = v9fs_create(v9ses, dir, dentry, NULL, perm, P9_OREAD);
 762         if (IS_ERR(fid)) {
 763                 err = PTR_ERR(fid);
 764                 fid = NULL;
 765         } else {
 766                 inc_nlink(dir);
 767                 v9fs_invalidate_inode_attr(dir);
 768         }
 769
 770         if (fid)
 771                 p9_client_clunk(fid);
 772
 773         return err;
 774 }
 775
 776 /**
 777  * v9fs_vfs_lookup - VFS lookup hook to "walk" to a new inode
 778  * @dir:  inode that is being walked from
 779  * @dentry: dentry that is being walked to?
 780  * @flags: lookup flags (unused)
 781  *
 782  */
 783
 784 struct dentry *v9fs_vfs_lookup(struct inode *dir, struct dentry *dentry,
 785                                       unsigned int flags)
 786 {
 787         struct dentry *res;
 788         struct v9fs_session_info *v9ses;
 789         struct p9_fid *dfid, *fid;
 790         struct inode *inode;
 791         const unsigned char *name;
 792
 793         p9_debug(P9_DEBUG_VFS, "dir: %p dentry: (%pd) %p flags: %x\n",
 794                  dir, dentry, dentry, flags);
 795
 796         if (dentry->d_name.len > NAME_MAX)
 797                 return ERR_PTR(-ENAMETOOLONG);
 798
 799         v9ses = v9fs_inode2v9ses(dir);
 800         /* We can walk d_parent because we hold the dir->i_mutex */
 801         dfid = v9fs_parent_fid(dentry);
 802         if (IS_ERR(dfid))
 803                 return ERR_CAST(dfid);
 804
 805         name = dentry->d_name.name;
 806         fid = p9_client_walk(dfid, 1, &name, 1);
 807         if (IS_ERR(fid)) {
 808                 if (fid == ERR_PTR(-ENOENT)) {
 809                         d_add(dentry, NULL);
 810                         return NULL;
 811                 }
 812                 return ERR_CAST(fid);
 813         }
 814         /*
 815          * Make sure we don't use a wrong inode due to parallel
 816          * unlink. For cached mode create calls request for new
 817          * inode. But with cache disabled, lookup should do this.
 818          */
 819         if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
 820                 inode = v9fs_get_inode_from_fid(v9ses, fid, dir->i_sb);
 821         else
 822                 inode = v9fs_get_new_inode_from_fid(v9ses, fid, dir->i_sb);
 823         if (IS_ERR(inode)) {
 824                 p9_client_clunk(fid);
 825                 return ERR_CAST(inode);
 826         }
 827         /*
 828          * If we had a rename on the server and a parallel lookup
 829          * for the new name, then make sure we instantiate with
 830          * the new name. ie look up for a/b, while on server somebody
 831          * moved b under k and client parallely did a lookup for
 832          * k/b.
 833          */
 834         res = d_splice_alias(inode, dentry);
 835         if (!res)
 836                 v9fs_fid_add(dentry, fid);
 837         else if (!IS_ERR(res))
 838                 v9fs_fid_add(res, fid);
 839         else
 840                 p9_client_clunk(fid);
 841         return res;
 842 }
 843
 844 static int
 845 v9fs_vfs_atomic_open(struct inode *dir, struct dentry *dentry,
 846                      struct file *file, unsigned flags, umode_t mode,
 847                      int *opened)
 848 {
 849         int err;
 850         u32 perm;
 851         struct v9fs_inode *v9inode;
 852         struct v9fs_session_info *v9ses;
 853         struct p9_fid *fid, *inode_fid;
 854         struct dentry *res = NULL;
 855
 856         if (d_in_lookup(dentry)) {
 857                 res = v9fs_vfs_lookup(dir, dentry, 0);
 858                 if (IS_ERR(res))
 859                         return PTR_ERR(res);
 860
 861                 if (res)
 862                         dentry = res;
 863         }
 864
 865         /* Only creates */
 866         if (!(flags & O_CREAT) || d_really_is_positive(dentry))
 867                 return finish_no_open(file, res);
 868
 869         err = 0;
 870
 871         v9ses = v9fs_inode2v9ses(dir);
 872         perm = unixmode2p9mode(v9ses, mode);
 873         fid = v9fs_create(v9ses, dir, dentry, NULL, perm,
 874                                 v9fs_uflags2omode(flags,
 875                                                 v9fs_proto_dotu(v9ses)));
 876         if (IS_ERR(fid)) {
 877                 err = PTR_ERR(fid);
 878                 fid = NULL;
 879                 goto error;
 880         }
 881
 882         v9fs_invalidate_inode_attr(dir);
 883         v9inode = V9FS_I(d_inode(dentry));
 884         mutex_lock(&v9inode->v_mutex);
 885         if ((v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE) &&
 886             !v9inode->writeback_fid &&
 887             ((flags & O_ACCMODE) != O_RDONLY)) {
 888                 /*
 889                  * clone a fid and add it to writeback_fid
 890                  * we do it during open time instead of
 891                  * page dirty time via write_begin/page_mkwrite
 892                  * because we want write after unlink usecase
 893                  * to work.
 894                  */
 895                 inode_fid = v9fs_writeback_fid(dentry);
 896                 if (IS_ERR(inode_fid)) {
 897                         err = PTR_ERR(inode_fid);
 898                         mutex_unlock(&v9inode->v_mutex);
 899                         goto error;
 900                 }
 901                 v9inode->writeback_fid = (void *) inode_fid;
 902         }
 903         mutex_unlock(&v9inode->v_mutex);
 904         err = finish_open(file, dentry, generic_file_open, opened);
 905         if (err)
 906                 goto error;
 907
 908         file->private_data = fid;
 909         if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
 910                 v9fs_cache_inode_set_cookie(d_inode(dentry), file);
 911
 912         *opened |= FILE_CREATED;
 913 out:
 914         dput(res);
 915         return err;
 916
 917 error:
 918         if (fid)
 919                 p9_client_clunk(fid);
 920         goto out;
 921 }
 922
 923 /**
 924  * v9fs_vfs_unlink - VFS unlink hook to delete an inode
 925  * @i:  inode that is being unlinked
 926  * @d: dentry that is being unlinked
 927  *
 928  */
 929
 930 int v9fs_vfs_unlink(struct inode *i, struct dentry *d)
 931 {
 932         return v9fs_remove(i, d, 0);
 933 }
 934
 935 /**
 936  * v9fs_vfs_rmdir - VFS unlink hook to delete a directory
 937  * @i:  inode that is being unlinked
 938  * @d: dentry that is being unlinked
 939  *
 940  */
 941
 942 int v9fs_vfs_rmdir(struct inode *i, struct dentry *d)
 943 {
 944         return v9fs_remove(i, d, AT_REMOVEDIR);
 945 }
 946
 947 /**
 948  * v9fs_vfs_rename - VFS hook to rename an inode
 949  * @old_dir:  old dir inode
 950  * @old_dentry: old dentry
 951  * @new_dir: new dir inode
 952  * @new_dentry: new dentry
 953  *
 954  */
 955
 956 int
 957 v9fs_vfs_rename(struct inode *old_dir, struct dentry *old_dentry,
 958                 struct inode *new_dir, struct dentry *new_dentry,
 959                 unsigned int flags)
 960 {
 961         int retval;
 962         struct inode *old_inode;
 963         struct inode *new_inode;
 964         struct v9fs_session_info *v9ses;
 965         struct p9_fid *oldfid;
 966         struct p9_fid *olddirfid;
 967         struct p9_fid *newdirfid;
 968         struct p9_wstat wstat;
 969
 970         if (flags)
 971                 return -EINVAL;
 972
 973         p9_debug(P9_DEBUG_VFS, "\n");
 974         retval = 0;
 975         old_inode = d_inode(old_dentry);
 976         new_inode = d_inode(new_dentry);
 977         v9ses = v9fs_inode2v9ses(old_inode);
 978         oldfid = v9fs_fid_lookup(old_dentry);
 979         if (IS_ERR(oldfid))
 980                 return PTR_ERR(oldfid);
 981
 982         olddirfid = clone_fid(v9fs_parent_fid(old_dentry));
 983         if (IS_ERR(olddirfid)) {
 984                 retval = PTR_ERR(olddirfid);
 985                 goto done;
 986         }
 987
 988         newdirfid = clone_fid(v9fs_parent_fid(new_dentry));
 989         if (IS_ERR(newdirfid)) {
 990                 retval = PTR_ERR(newdirfid);
 991                 goto clunk_olddir;
 992         }
 993
 994         down_write(&v9ses->rename_sem);
 995         if (v9fs_proto_dotl(v9ses)) {
 996                 retval = p9_client_renameat(olddirfid, old_dentry->d_name.name,
 997                                             newdirfid, new_dentry->d_name.name);
 998                 if (retval == -EOPNOTSUPP)
 999                         retval = p9_client_rename(oldfid, newdirfid,
1000                                                   new_dentry->d_name.name);
1001                 if (retval != -EOPNOTSUPP)
1002                         goto clunk_newdir;
1003         }
1004         if (old_dentry->d_parent != new_dentry->d_parent) {
1005                 /*
1006                  * 9P .u can only handle file rename in the same directory
1007                  */
1008
1009                 p9_debug(P9_DEBUG_ERROR, "old dir and new dir are different\n");
1010                 retval = -EXDEV;
1011                 goto clunk_newdir;
1012         }
1013         v9fs_blank_wstat(&wstat);
1014         wstat.muid = v9ses->uname;
1015         wstat.name = new_dentry->d_name.name;
1016         retval = p9_client_wstat(oldfid, &wstat);
1017
1018 clunk_newdir:
1019         if (!retval) {
1020                 if (new_inode) {
1021                         if (S_ISDIR(new_inode->i_mode))
1022                                 clear_nlink(new_inode);
1023                         else
1024                                 drop_nlink(new_inode);
1025                 }
1026                 if (S_ISDIR(old_inode->i_mode)) {
1027                         if (!new_inode)
1028                                 inc_nlink(new_dir);
1029                         drop_nlink(old_dir);
1030                 }
1031                 v9fs_invalidate_inode_attr(old_inode);
1032                 v9fs_invalidate_inode_attr(old_dir);
1033                 v9fs_invalidate_inode_attr(new_dir);
1034
1035                 /* successful rename */
1036                 d_move(old_dentry, new_dentry);
1037         }
1038         up_write(&v9ses->rename_sem);
1039         p9_client_clunk(newdirfid);
1040
1041 clunk_olddir:
1042         p9_client_clunk(olddirfid);
1043
1044 done:
1045         return retval;
1046 }
1047
1048 /**
1049  * v9fs_vfs_getattr - retrieve file metadata
1050  * @path: Object to query
1051  * @stat: metadata structure to populate
1052  * @request_mask: Mask of STATX_xxx flags indicating the caller's interests
1053  * @flags: AT_STATX_xxx setting
1054  *
1055  */
1056
1057 static int
1058 v9fs_vfs_getattr(const struct path *path, struct kstat *stat,
1059                  u32 request_mask, unsigned int flags)
1060 {
1061         struct dentry *dentry = path->dentry;
1062         struct v9fs_session_info *v9ses;
1063         struct p9_fid *fid;
1064         struct p9_wstat *st;
1065
1066         p9_debug(P9_DEBUG_VFS, "dentry: %p\n", dentry);
1067         v9ses = v9fs_dentry2v9ses(dentry);
1068         if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE) {
1069                 generic_fillattr(d_inode(dentry), stat);
1070                 return 0;
1071         }
1072         fid = v9fs_fid_lookup(dentry);
1073         if (IS_ERR(fid))
1074                 return PTR_ERR(fid);
1075
1076         st = p9_client_stat(fid);
1077         if (IS_ERR(st))
1078                 return PTR_ERR(st);
1079
1080         v9fs_stat2inode(st, d_inode(dentry), dentry->d_sb);
1081         generic_fillattr(d_inode(dentry), stat);
1082
1083         p9stat_free(st);
1084         kfree(st);
1085         return 0;
1086 }
1087
1088 /**
1089  * v9fs_vfs_setattr - set file metadata
1090  * @dentry: file whose metadata to set
1091  * @iattr: metadata assignment structure
1092  *
1093  */
1094
1095 static int v9fs_vfs_setattr(struct dentry *dentry, struct iattr *iattr)
1096 {
1097         int retval;
1098         struct v9fs_session_info *v9ses;
1099         struct p9_fid *fid;
1100         struct p9_wstat wstat;
1101
1102         p9_debug(P9_DEBUG_VFS, "\n");
1103         retval = setattr_prepare(dentry, iattr);
1104         if (retval)
1105                 return retval;
1106
1107         retval = -EPERM;
1108         v9ses = v9fs_dentry2v9ses(dentry);
1109         fid = v9fs_fid_lookup(dentry);
1110         if(IS_ERR(fid))
1111                 return PTR_ERR(fid);
1112
1113         v9fs_blank_wstat(&wstat);
1114         if (iattr->ia_valid & ATTR_MODE)
1115                 wstat.mode = unixmode2p9mode(v9ses, iattr->ia_mode);
1116
1117         if (iattr->ia_valid & ATTR_MTIME)
1118                 wstat.mtime = iattr->ia_mtime.tv_sec;
1119
1120         if (iattr->ia_valid & ATTR_ATIME)
1121                 wstat.atime = iattr->ia_atime.tv_sec;
1122
1123         if (iattr->ia_valid & ATTR_SIZE)
1124                 wstat.length = iattr->ia_size;
1125
1126         if (v9fs_proto_dotu(v9ses)) {
1127                 if (iattr->ia_valid & ATTR_UID)
1128                         wstat.n_uid = iattr->ia_uid;
1129
1130                 if (iattr->ia_valid & ATTR_GID)
1131                         wstat.n_gid = iattr->ia_gid;
1132         }
1133
1134         /* Write all dirty data */
1135         if (d_is_reg(dentry))
1136                 filemap_write_and_wait(d_inode(dentry)->i_mapping);
1137
1138         retval = p9_client_wstat(fid, &wstat);
1139         if (retval < 0)
1140                 return retval;
1141
1142         if ((iattr->ia_valid & ATTR_SIZE) &&
1143             iattr->ia_size != i_size_read(d_inode(dentry)))
1144                 truncate_setsize(d_inode(dentry), iattr->ia_size);
1145
1146         v9fs_invalidate_inode_attr(d_inode(dentry));
1147
1148         setattr_copy(d_inode(dentry), iattr);
1149         mark_inode_dirty(d_inode(dentry));
1150         return 0;
1151 }
1152
1153 /**
1154  * v9fs_stat2inode - populate an inode structure with mistat info
1155  * @stat: Plan 9 metadata (mistat) structure
1156  * @inode: inode to populate
1157  * @sb: superblock of filesystem
1158  *
1159  */
1160
1161 void
1162 v9fs_stat2inode(struct p9_wstat *stat, struct inode *inode,
1163         struct super_block *sb)
1164 {
1165         umode_t mode;
1166         char ext[32];
1167         char tag_name[14];
1168         unsigned int i_nlink;
1169         struct v9fs_session_info *v9ses = sb->s_fs_info;
1170         struct v9fs_inode *v9inode = V9FS_I(inode);
1171
1172         set_nlink(inode, 1);
1173
1174         inode->i_atime.tv_sec = stat->atime;
1175         inode->i_mtime.tv_sec = stat->mtime;
1176         inode->i_ctime.tv_sec = stat->mtime;
1177
1178         inode->i_uid = v9ses->dfltuid;
1179         inode->i_gid = v9ses->dfltgid;
1180
1181         if (v9fs_proto_dotu(v9ses)) {
1182                 inode->i_uid = stat->n_uid;
1183                 inode->i_gid = stat->n_gid;
1184         }
1185         if ((S_ISREG(inode->i_mode)) || (S_ISDIR(inode->i_mode))) {
1186                 if (v9fs_proto_dotu(v9ses) && (stat->extension[0] != '\0')) {
1187                         /*
1188                          * Hadlink support got added later to
1189                          * to the .u extension. So there can be
1190                          * server out there that doesn't support
1191                          * this even with .u extension. So check
1192                          * for non NULL stat->extension
1193                          */
1194                         strlcpy(ext, stat->extension, sizeof(ext));
1195                         /* HARDLINKCOUNT %u */
1196                         sscanf(ext, "%13s %u", tag_name, &i_nlink);
1197                         if (!strncmp(tag_name, "HARDLINKCOUNT", 13))
1198                                 set_nlink(inode, i_nlink);
1199                 }
1200         }
1201         mode = p9mode2perm(v9ses, stat);
1202         mode |= inode->i_mode & ~S_IALLUGO;
1203         inode->i_mode = mode;
1204         i_size_write(inode, stat->length);
1205
1206         /* not real number of blocks, but 512 byte ones ... */
1207         inode->i_blocks = (i_size_read(inode) + 512 - 1) >> 9;
1208         v9inode->cache_validity &= ~V9FS_INO_INVALID_ATTR;
1209 }
1210
1211 /**
1212  * v9fs_qid2ino - convert qid into inode number
1213  * @qid: qid to hash
1214  *
1215  * BUG: potential for inode number collisions?
1216  */
1217
1218 ino_t v9fs_qid2ino(struct p9_qid *qid)
1219 {
1220         u64 path = qid->path + 2;
1221         ino_t i = 0;
1222
1223         if (sizeof(ino_t) == sizeof(path))
1224                 memcpy(&i, &path, sizeof(ino_t));
1225         else
1226                 i = (ino_t) (path ^ (path >> 32));
1227
1228         return i;
1229 }
1230
1231 /**
1232  * v9fs_vfs_get_link - follow a symlink path
1233  * @dentry: dentry for symlink
1234  * @inode: inode for symlink
1235  * @done: delayed call for when we are done with the return value
1236  */
1237
1238 static const char *v9fs_vfs_get_link(struct dentry *dentry,
1239                                      struct inode *inode,
1240                                      struct delayed_call *done)
1241 {
1242         struct v9fs_session_info *v9ses;
1243         struct p9_fid *fid;
1244         struct p9_wstat *st;
1245         char *res;
1246
1247         if (!dentry)
1248                 return ERR_PTR(-ECHILD);
1249
1250         v9ses = v9fs_dentry2v9ses(dentry);
1251         fid = v9fs_fid_lookup(dentry);
1252         p9_debug(P9_DEBUG_VFS, "%pd\n", dentry);
1253
1254         if (IS_ERR(fid))
1255                 return ERR_CAST(fid);
1256
1257         if (!v9fs_proto_dotu(v9ses))
1258                 return ERR_PTR(-EBADF);
1259
1260         st = p9_client_stat(fid);
1261         if (IS_ERR(st))
1262                 return ERR_CAST(st);
1263
1264         if (!(st->mode & P9_DMSYMLINK)) {
1265                 p9stat_free(st);
1266                 kfree(st);
1267                 return ERR_PTR(-EINVAL);
1268         }
1269         res = st->extension;
1270         st->extension = NULL;
1271         if (strlen(res) >= PATH_MAX)
1272                 res[PATH_MAX - 1] = '\0';
1273
1274         p9stat_free(st);
1275         kfree(st);
1276         set_delayed_call(done, kfree_link, res);
1277         return res;
1278 }
1279
1280 /**
1281  * v9fs_vfs_mkspecial - create a special file
1282  * @dir: inode to create special file in
1283  * @dentry: dentry to create
1284  * @perm: mode to create special file
1285  * @extension: 9p2000.u format extension string representing special file
1286  *
1287  */
1288
1289 static int v9fs_vfs_mkspecial(struct inode *dir, struct dentry *dentry,
1290         u32 perm, const char *extension)
1291 {
1292         struct p9_fid *fid;
1293         struct v9fs_session_info *v9ses;
1294
1295         v9ses = v9fs_inode2v9ses(dir);
1296         if (!v9fs_proto_dotu(v9ses)) {
1297                 p9_debug(P9_DEBUG_ERROR, "not extended\n");
1298                 return -EPERM;
1299         }
1300
1301         fid = v9fs_create(v9ses, dir, dentry, (char *) extension, perm,
1302                                                                 P9_OREAD);
1303         if (IS_ERR(fid))
1304                 return PTR_ERR(fid);
1305
1306         v9fs_invalidate_inode_attr(dir);
1307         p9_client_clunk(fid);
1308         return 0;
1309 }
1310
1311 /**
1312  * v9fs_vfs_symlink - helper function to create symlinks
1313  * @dir: directory inode containing symlink
1314  * @dentry: dentry for symlink
1315  * @symname: symlink data
1316  *
1317  * See Also: 9P2000.u RFC for more information
1318  *
1319  */
1320
1321 static int
1322 v9fs_vfs_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
1323 {
1324         p9_debug(P9_DEBUG_VFS, " %lu,%pd,%s\n",
1325                  dir->i_ino, dentry, symname);
1326
1327         return v9fs_vfs_mkspecial(dir, dentry, P9_DMSYMLINK, symname);
1328 }
1329
1330 #define U32_MAX_DIGITS 10
1331
1332 /**
1333  * v9fs_vfs_link - create a hardlink
1334  * @old_dentry: dentry for file to link to
1335  * @dir: inode destination for new link
1336  * @dentry: dentry for link
1337  *
1338  */
1339
1340 static int
1341 v9fs_vfs_link(struct dentry *old_dentry, struct inode *dir,
1342               struct dentry *dentry)
1343 {
1344         int retval;
1345         char name[1 + U32_MAX_DIGITS + 2]; /* sign + number + \n + \0 */
1346         struct p9_fid *oldfid;
1347
1348         p9_debug(P9_DEBUG_VFS, " %lu,%pd,%pd\n",
1349                  dir->i_ino, dentry, old_dentry);
1350
1351         oldfid = v9fs_fid_clone(old_dentry);
1352         if (IS_ERR(oldfid))
1353                 return PTR_ERR(oldfid);
1354
1355         sprintf(name, "%d\n", oldfid->fid);
1356         retval = v9fs_vfs_mkspecial(dir, dentry, P9_DMLINK, name);
1357         if (!retval) {
1358                 v9fs_refresh_inode(oldfid, d_inode(old_dentry));
1359                 v9fs_invalidate_inode_attr(dir);
1360         }
1361         p9_client_clunk(oldfid);
1362         return retval;
1363 }
1364
1365 /**
1366  * v9fs_vfs_mknod - create a special file
1367  * @dir: inode destination for new link
1368  * @dentry: dentry for file
1369  * @mode: mode for creation
1370  * @rdev: device associated with special file
1371  *
1372  */
1373
1374 static int
1375 v9fs_vfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t rdev)
1376 {
1377         struct v9fs_session_info *v9ses = v9fs_inode2v9ses(dir);
1378         int retval;
1379         char name[2 + U32_MAX_DIGITS + 1 + U32_MAX_DIGITS + 1];
1380         u32 perm;
1381
1382         p9_debug(P9_DEBUG_VFS, " %lu,%pd mode: %hx MAJOR: %u MINOR: %u\n",
1383                  dir->i_ino, dentry, mode,
1384                  MAJOR(rdev), MINOR(rdev));
1385
1386         /* build extension */
1387         if (S_ISBLK(mode))
1388                 sprintf(name, "b %u %u", MAJOR(rdev), MINOR(rdev));
1389         else if (S_ISCHR(mode))
1390                 sprintf(name, "c %u %u", MAJOR(rdev), MINOR(rdev));
1391         else
1392                 *name = 0;
1393
1394         perm = unixmode2p9mode(v9ses, mode);
1395         retval = v9fs_vfs_mkspecial(dir, dentry, perm, name);
1396
1397         return retval;
1398 }
1399
1400 int v9fs_refresh_inode(struct p9_fid *fid, struct inode *inode)
1401 {
1402         int umode;
1403         dev_t rdev;
1404         loff_t i_size;
1405         struct p9_wstat *st;
1406         struct v9fs_session_info *v9ses;
1407
1408         v9ses = v9fs_inode2v9ses(inode);
1409         st = p9_client_stat(fid);
1410         if (IS_ERR(st))
1411                 return PTR_ERR(st);
1412         /*
1413          * Don't update inode if the file type is different
1414          */
1415         umode = p9mode2unixmode(v9ses, st, &rdev);
1416         if ((inode->i_mode & S_IFMT) != (umode & S_IFMT))
1417                 goto out;
1418
1419         spin_lock(&inode->i_lock);
1420         /*
1421          * We don't want to refresh inode->i_size,
1422          * because we may have cached data
1423          */
1424         i_size = inode->i_size;
1425         v9fs_stat2inode(st, inode, inode->i_sb);
1426         if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
1427                 inode->i_size = i_size;
1428         spin_unlock(&inode->i_lock);
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         .get_link = v9fs_vfs_get_link,
1470         .getattr = v9fs_vfs_getattr,
1471         .setattr = v9fs_vfs_setattr,
1472 };
1473