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                 strncpy(ext, stat->extension, sizeof(ext));
 150                 sscanf(ext, "%c %u %u", &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 (uflags & O_TRUNC)
 196                 ret |= P9_OTRUNC;
 197
 198         if (extended) {
 199                 if (uflags & O_EXCL)
 200                         ret |= P9_OEXCL;
 201
 202                 if (uflags & O_APPEND)
 203                         ret |= P9_OAPPEND;
 204         }
 205
 206         return ret;
 207 }
 208
 209 /**
 210  * v9fs_blank_wstat - helper function to setup a 9P stat structure
 211  * @wstat: structure to initialize
 212  *
 213  */
 214
 215 void
 216 v9fs_blank_wstat(struct p9_wstat *wstat)
 217 {
 218         wstat->type = ~0;
 219         wstat->dev = ~0;
 220         wstat->qid.type = ~0;
 221         wstat->qid.version = ~0;
 222         *((long long *)&wstat->qid.path) = ~0;
 223         wstat->mode = ~0;
 224         wstat->atime = ~0;
 225         wstat->mtime = ~0;
 226         wstat->length = ~0;
 227         wstat->name = NULL;
 228         wstat->uid = NULL;
 229         wstat->gid = NULL;
 230         wstat->muid = NULL;
 231         wstat->n_uid = ~0;
 232         wstat->n_gid = ~0;
 233         wstat->n_muid = ~0;
 234         wstat->extension = NULL;
 235 }
 236
 237 /**
 238  * v9fs_alloc_inode - helper function to allocate an inode
 239  *
 240  */
 241 struct inode *v9fs_alloc_inode(struct super_block *sb)
 242 {
 243         struct v9fs_inode *v9inode;
 244         v9inode = (struct v9fs_inode *)kmem_cache_alloc(v9fs_inode_cache,
 245                                                         GFP_KERNEL);
 246         if (!v9inode)
 247                 return NULL;
 248 #ifdef CONFIG_9P_FSCACHE
 249         v9inode->fscache = NULL;
 250         spin_lock_init(&v9inode->fscache_lock);
 251 #endif
 252         v9inode->writeback_fid = NULL;
 253         v9inode->cache_validity = 0;
 254         mutex_init(&v9inode->v_mutex);
 255         return &v9inode->vfs_inode;
 256 }
 257
 258 /**
 259  * v9fs_destroy_inode - destroy an inode
 260  *
 261  */
 262
 263 static void v9fs_i_callback(struct rcu_head *head)
 264 {
 265         struct inode *inode = container_of(head, struct inode, i_rcu);
 266         kmem_cache_free(v9fs_inode_cache, V9FS_I(inode));
 267 }
 268
 269 void v9fs_destroy_inode(struct inode *inode)
 270 {
 271         call_rcu(&inode->i_rcu, v9fs_i_callback);
 272 }
 273
 274 int v9fs_init_inode(struct v9fs_session_info *v9ses,
 275                     struct inode *inode, umode_t mode, dev_t rdev)
 276 {
 277         int err = 0;
 278
 279         inode_init_owner(inode, NULL, mode);
 280         inode->i_blocks = 0;
 281         inode->i_rdev = rdev;
 282         inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 283         inode->i_mapping->a_ops = &v9fs_addr_operations;
 284
 285         switch (mode & S_IFMT) {
 286         case S_IFIFO:
 287         case S_IFBLK:
 288         case S_IFCHR:
 289         case S_IFSOCK:
 290                 if (v9fs_proto_dotl(v9ses)) {
 291                         inode->i_op = &v9fs_file_inode_operations_dotl;
 292                 } else if (v9fs_proto_dotu(v9ses)) {
 293                         inode->i_op = &v9fs_file_inode_operations;
 294                 } else {
 295                         p9_debug(P9_DEBUG_ERROR,
 296                                  "special files without extended mode\n");
 297                         err = -EINVAL;
 298                         goto error;
 299                 }
 300                 init_special_inode(inode, inode->i_mode, inode->i_rdev);
 301                 break;
 302         case S_IFREG:
 303                 if (v9fs_proto_dotl(v9ses)) {
 304                         inode->i_op = &v9fs_file_inode_operations_dotl;
 305                         if (v9ses->cache)
 306                                 inode->i_fop =
 307                                         &v9fs_cached_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)
 313                                 inode->i_fop = &v9fs_cached_file_operations;
 314                         else
 315                                 inode->i_fop = &v9fs_file_operations;
 316                 }
 317
 318                 break;
 319         case S_IFLNK:
 320                 if (!v9fs_proto_dotu(v9ses) && !v9fs_proto_dotl(v9ses)) {
 321                         p9_debug(P9_DEBUG_ERROR,
 322                                  "extended modes used with legacy protocol\n");
 323                         err = -EINVAL;
 324                         goto error;
 325                 }
 326
 327                 if (v9fs_proto_dotl(v9ses))
 328                         inode->i_op = &v9fs_symlink_inode_operations_dotl;
 329                 else
 330                         inode->i_op = &v9fs_symlink_inode_operations;
 331
 332                 break;
 333         case S_IFDIR:
 334                 inc_nlink(inode);
 335                 if (v9fs_proto_dotl(v9ses))
 336                         inode->i_op = &v9fs_dir_inode_operations_dotl;
 337                 else if (v9fs_proto_dotu(v9ses))
 338                         inode->i_op = &v9fs_dir_inode_operations_dotu;
 339                 else
 340                         inode->i_op = &v9fs_dir_inode_operations;
 341
 342                 if (v9fs_proto_dotl(v9ses))
 343                         inode->i_fop = &v9fs_dir_operations_dotl;
 344                 else
 345                         inode->i_fop = &v9fs_dir_operations;
 346
 347                 break;
 348         default:
 349                 p9_debug(P9_DEBUG_ERROR, "BAD mode 0x%hx S_IFMT 0x%x\n",
 350                          mode, mode & S_IFMT);
 351                 err = -EINVAL;
 352                 goto error;
 353         }
 354 error:
 355         return err;
 356
 357 }
 358
 359 /**
 360  * v9fs_get_inode - helper function to setup an inode
 361  * @sb: superblock
 362  * @mode: mode to setup inode with
 363  *
 364  */
 365
 366 struct inode *v9fs_get_inode(struct super_block *sb, umode_t mode, dev_t rdev)
 367 {
 368         int err;
 369         struct inode *inode;
 370         struct v9fs_session_info *v9ses = sb->s_fs_info;
 371
 372         p9_debug(P9_DEBUG_VFS, "super block: %p mode: %ho\n", sb, mode);
 373
 374         inode = new_inode(sb);
 375         if (!inode) {
 376                 pr_warn("%s (%d): Problem allocating inode\n",
 377                         __func__, task_pid_nr(current));
 378                 return ERR_PTR(-ENOMEM);
 379         }
 380         err = v9fs_init_inode(v9ses, inode, mode, rdev);
 381         if (err) {
 382                 iput(inode);
 383                 return ERR_PTR(err);
 384         }
 385         return inode;
 386 }
 387
 388 /*
 389 static struct v9fs_fid*
 390 v9fs_clone_walk(struct v9fs_session_info *v9ses, u32 fid, struct dentry *dentry)
 391 {
 392         int err;
 393         int nfid;
 394         struct v9fs_fid *ret;
 395         struct v9fs_fcall *fcall;
 396
 397         nfid = v9fs_get_idpool(&v9ses->fidpool);
 398         if (nfid < 0) {
 399                 eprintk(KERN_WARNING, "no free fids available\n");
 400                 return ERR_PTR(-ENOSPC);
 401         }
 402
 403         err = v9fs_t_walk(v9ses, fid, nfid, (char *) dentry->d_name.name,
 404                 &fcall);
 405
 406         if (err < 0) {
 407                 if (fcall && fcall->id == RWALK)
 408                         goto clunk_fid;
 409
 410                 PRINT_FCALL_ERROR("walk error", fcall);
 411                 v9fs_put_idpool(nfid, &v9ses->fidpool);
 412                 goto error;
 413         }
 414
 415         kfree(fcall);
 416         fcall = NULL;
 417         ret = v9fs_fid_create(v9ses, nfid);
 418         if (!ret) {
 419                 err = -ENOMEM;
 420                 goto clunk_fid;
 421         }
 422
 423         err = v9fs_fid_insert(ret, dentry);
 424         if (err < 0) {
 425                 v9fs_fid_destroy(ret);
 426                 goto clunk_fid;
 427         }
 428
 429         return ret;
 430
 431 clunk_fid:
 432         v9fs_t_clunk(v9ses, nfid);
 433
 434 error:
 435         kfree(fcall);
 436         return ERR_PTR(err);
 437 }
 438 */
 439
 440
 441 /**
 442  * v9fs_clear_inode - release an inode
 443  * @inode: inode to release
 444  *
 445  */
 446 void v9fs_evict_inode(struct inode *inode)
 447 {
 448         struct v9fs_inode *v9inode = V9FS_I(inode);
 449
 450         truncate_inode_pages(inode->i_mapping, 0);
 451         end_writeback(inode);
 452         filemap_fdatawrite(inode->i_mapping);
 453
 454 #ifdef CONFIG_9P_FSCACHE
 455         v9fs_cache_inode_put_cookie(inode);
 456 #endif
 457         /* clunk the fid stashed in writeback_fid */
 458         if (v9inode->writeback_fid) {
 459                 p9_client_clunk(v9inode->writeback_fid);
 460                 v9inode->writeback_fid = NULL;
 461         }
 462 }
 463
 464 static int v9fs_test_inode(struct inode *inode, void *data)
 465 {
 466         int umode;
 467         dev_t rdev;
 468         struct v9fs_inode *v9inode = V9FS_I(inode);
 469         struct p9_wstat *st = (struct p9_wstat *)data;
 470         struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
 471
 472         umode = p9mode2unixmode(v9ses, st, &rdev);
 473         /* don't match inode of different type */
 474         if ((inode->i_mode & S_IFMT) != (umode & S_IFMT))
 475                 return 0;
 476
 477         /* compare qid details */
 478         if (memcmp(&v9inode->qid.version,
 479                    &st->qid.version, sizeof(v9inode->qid.version)))
 480                 return 0;
 481
 482         if (v9inode->qid.type != st->qid.type)
 483                 return 0;
 484         return 1;
 485 }
 486
 487 static int v9fs_test_new_inode(struct inode *inode, void *data)
 488 {
 489         return 0;
 490 }
 491
 492 static int v9fs_set_inode(struct inode *inode,  void *data)
 493 {
 494         struct v9fs_inode *v9inode = V9FS_I(inode);
 495         struct p9_wstat *st = (struct p9_wstat *)data;
 496
 497         memcpy(&v9inode->qid, &st->qid, sizeof(st->qid));
 498         return 0;
 499 }
 500
 501 static struct inode *v9fs_qid_iget(struct super_block *sb,
 502                                    struct p9_qid *qid,
 503                                    struct p9_wstat *st,
 504                                    int new)
 505 {
 506         dev_t rdev;
 507         int retval;
 508         umode_t umode;
 509         unsigned long i_ino;
 510         struct inode *inode;
 511         struct v9fs_session_info *v9ses = sb->s_fs_info;
 512         int (*test)(struct inode *, void *);
 513
 514         if (new)
 515                 test = v9fs_test_new_inode;
 516         else
 517                 test = v9fs_test_inode;
 518
 519         i_ino = v9fs_qid2ino(qid);
 520         inode = iget5_locked(sb, i_ino, test, v9fs_set_inode, st);
 521         if (!inode)
 522                 return ERR_PTR(-ENOMEM);
 523         if (!(inode->i_state & I_NEW))
 524                 return inode;
 525         /*
 526          * initialize the inode with the stat info
 527          * FIXME!! we may need support for stale inodes
 528          * later.
 529          */
 530         inode->i_ino = i_ino;
 531         umode = p9mode2unixmode(v9ses, st, &rdev);
 532         retval = v9fs_init_inode(v9ses, inode, umode, rdev);
 533         if (retval)
 534                 goto error;
 535
 536         v9fs_stat2inode(st, inode, sb);
 537 #ifdef CONFIG_9P_FSCACHE
 538         v9fs_cache_inode_get_cookie(inode);
 539 #endif
 540         unlock_new_inode(inode);
 541         return inode;
 542 error:
 543         unlock_new_inode(inode);
 544         iput(inode);
 545         return ERR_PTR(retval);
 546
 547 }
 548
 549 struct inode *
 550 v9fs_inode_from_fid(struct v9fs_session_info *v9ses, struct p9_fid *fid,
 551                     struct super_block *sb, int new)
 552 {
 553         struct p9_wstat *st;
 554         struct inode *inode = NULL;
 555
 556         st = p9_client_stat(fid);
 557         if (IS_ERR(st))
 558                 return ERR_CAST(st);
 559
 560         inode = v9fs_qid_iget(sb, &st->qid, st, new);
 561         p9stat_free(st);
 562         kfree(st);
 563         return inode;
 564 }
 565
 566 /**
 567  * v9fs_at_to_dotl_flags- convert Linux specific AT flags to
 568  * plan 9 AT flag.
 569  * @flags: flags to convert
 570  */
 571 static int v9fs_at_to_dotl_flags(int flags)
 572 {
 573         int rflags = 0;
 574         if (flags & AT_REMOVEDIR)
 575                 rflags |= P9_DOTL_AT_REMOVEDIR;
 576         return rflags;
 577 }
 578
 579 /**
 580  * v9fs_remove - helper function to remove files and directories
 581  * @dir: directory inode that is being deleted
 582  * @dentry:  dentry that is being deleted
 583  * @rmdir: removing a directory
 584  *
 585  */
 586
 587 static int v9fs_remove(struct inode *dir, struct dentry *dentry, int flags)
 588 {
 589         struct inode *inode;
 590         int retval = -EOPNOTSUPP;
 591         struct p9_fid *v9fid, *dfid;
 592         struct v9fs_session_info *v9ses;
 593
 594         p9_debug(P9_DEBUG_VFS, "inode: %p dentry: %p rmdir: %x\n",
 595                  dir, dentry, flags);
 596
 597         v9ses = v9fs_inode2v9ses(dir);
 598         inode = dentry->d_inode;
 599         dfid = v9fs_fid_lookup(dentry->d_parent);
 600         if (IS_ERR(dfid)) {
 601                 retval = PTR_ERR(dfid);
 602                 p9_debug(P9_DEBUG_VFS, "fid lookup failed %d\n", retval);
 603                 return retval;
 604         }
 605         if (v9fs_proto_dotl(v9ses))
 606                 retval = p9_client_unlinkat(dfid, dentry->d_name.name,
 607                                             v9fs_at_to_dotl_flags(flags));
 608         if (retval == -EOPNOTSUPP) {
 609                 /* Try the one based on path */
 610                 v9fid = v9fs_fid_clone(dentry);
 611                 if (IS_ERR(v9fid))
 612                         return PTR_ERR(v9fid);
 613                 retval = p9_client_remove(v9fid);
 614         }
 615         if (!retval) {
 616                 /*
 617                  * directories on unlink should have zero
 618                  * link count
 619                  */
 620                 if (flags & AT_REMOVEDIR) {
 621                         clear_nlink(inode);
 622                         drop_nlink(dir);
 623                 } else
 624                         drop_nlink(inode);
 625
 626                 v9fs_invalidate_inode_attr(inode);
 627                 v9fs_invalidate_inode_attr(dir);
 628         }
 629         return retval;
 630 }
 631
 632 /**
 633  * v9fs_create - Create a file
 634  * @v9ses: session information
 635  * @dir: directory that dentry is being created in
 636  * @dentry:  dentry that is being created
 637  * @extension: 9p2000.u extension string to support devices, etc.
 638  * @perm: create permissions
 639  * @mode: open mode
 640  *
 641  */
 642 static struct p9_fid *
 643 v9fs_create(struct v9fs_session_info *v9ses, struct inode *dir,
 644                 struct dentry *dentry, char *extension, u32 perm, u8 mode)
 645 {
 646         int err;
 647         char *name;
 648         struct p9_fid *dfid, *ofid, *fid;
 649         struct inode *inode;
 650
 651         p9_debug(P9_DEBUG_VFS, "name %s\n", dentry->d_name.name);
 652
 653         err = 0;
 654         ofid = NULL;
 655         fid = NULL;
 656         name = (char *) dentry->d_name.name;
 657         dfid = v9fs_fid_lookup(dentry->d_parent);
 658         if (IS_ERR(dfid)) {
 659                 err = PTR_ERR(dfid);
 660                 p9_debug(P9_DEBUG_VFS, "fid lookup failed %d\n", err);
 661                 return ERR_PTR(err);
 662         }
 663
 664         /* clone a fid to use for creation */
 665         ofid = p9_client_walk(dfid, 0, NULL, 1);
 666         if (IS_ERR(ofid)) {
 667                 err = PTR_ERR(ofid);
 668                 p9_debug(P9_DEBUG_VFS, "p9_client_walk failed %d\n", err);
 669                 return ERR_PTR(err);
 670         }
 671
 672         err = p9_client_fcreate(ofid, name, perm, mode, extension);
 673         if (err < 0) {
 674                 p9_debug(P9_DEBUG_VFS, "p9_client_fcreate failed %d\n", err);
 675                 goto error;
 676         }
 677
 678         if (!(perm & P9_DMLINK)) {
 679                 /* now walk from the parent so we can get unopened fid */
 680                 fid = p9_client_walk(dfid, 1, &name, 1);
 681                 if (IS_ERR(fid)) {
 682                         err = PTR_ERR(fid);
 683                         p9_debug(P9_DEBUG_VFS,
 684                                    "p9_client_walk failed %d\n", err);
 685                         fid = NULL;
 686                         goto error;
 687                 }
 688                 /*
 689                  * instantiate inode and assign the unopened fid to the dentry
 690                  */
 691                 inode = v9fs_get_new_inode_from_fid(v9ses, fid, dir->i_sb);
 692                 if (IS_ERR(inode)) {
 693                         err = PTR_ERR(inode);
 694                         p9_debug(P9_DEBUG_VFS,
 695                                    "inode creation failed %d\n", err);
 696                         goto error;
 697                 }
 698                 err = v9fs_fid_add(dentry, fid);
 699                 if (err < 0)
 700                         goto error;
 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 files
 716  * @dir: directory inode that is being created
 717  * @dentry:  dentry that is being deleted
 718  * @mode: create permissions
 719  * @nd: path information
 720  *
 721  */
 722
 723 static int
 724 v9fs_vfs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
 725                 struct nameidata *nd)
 726 {
 727         int err;
 728         u32 perm;
 729         int flags;
 730         struct file *filp;
 731         struct v9fs_inode *v9inode;
 732         struct v9fs_session_info *v9ses;
 733         struct p9_fid *fid, *inode_fid;
 734
 735         err = 0;
 736         fid = NULL;
 737         v9ses = v9fs_inode2v9ses(dir);
 738         perm = unixmode2p9mode(v9ses, mode);
 739         if (nd)
 740                 flags = nd->intent.open.flags;
 741         else
 742                 flags = O_RDWR;
 743
 744         fid = v9fs_create(v9ses, dir, dentry, NULL, perm,
 745                                 v9fs_uflags2omode(flags,
 746                                                 v9fs_proto_dotu(v9ses)));
 747         if (IS_ERR(fid)) {
 748                 err = PTR_ERR(fid);
 749                 fid = NULL;
 750                 goto error;
 751         }
 752
 753         v9fs_invalidate_inode_attr(dir);
 754         /* if we are opening a file, assign the open fid to the file */
 755         if (nd) {
 756                 v9inode = V9FS_I(dentry->d_inode);
 757                 mutex_lock(&v9inode->v_mutex);
 758                 if (v9ses->cache && !v9inode->writeback_fid &&
 759                     ((flags & O_ACCMODE) != O_RDONLY)) {
 760                         /*
 761                          * clone a fid and add it to writeback_fid
 762                          * we do it during open time instead of
 763                          * page dirty time via write_begin/page_mkwrite
 764                          * because we want write after unlink usecase
 765                          * to work.
 766                          */
 767                         inode_fid = v9fs_writeback_fid(dentry);
 768                         if (IS_ERR(inode_fid)) {
 769                                 err = PTR_ERR(inode_fid);
 770                                 mutex_unlock(&v9inode->v_mutex);
 771                                 goto error;
 772                         }
 773                         v9inode->writeback_fid = (void *) inode_fid;
 774                 }
 775                 mutex_unlock(&v9inode->v_mutex);
 776                 filp = lookup_instantiate_filp(nd, dentry, generic_file_open);
 777                 if (IS_ERR(filp)) {
 778                         err = PTR_ERR(filp);
 779                         goto error;
 780                 }
 781
 782                 filp->private_data = fid;
 783 #ifdef CONFIG_9P_FSCACHE
 784                 if (v9ses->cache)
 785                         v9fs_cache_inode_set_cookie(dentry->d_inode, filp);
 786 #endif
 787         } else
 788                 p9_client_clunk(fid);
 789
 790         return 0;
 791
 792 error:
 793         if (fid)
 794                 p9_client_clunk(fid);
 795
 796         return err;
 797 }
 798
 799 /**
 800  * v9fs_vfs_mkdir - VFS mkdir hook to create a directory
 801  * @dir:  inode that is being unlinked
 802  * @dentry: dentry that is being unlinked
 803  * @mode: mode for new directory
 804  *
 805  */
 806
 807 static int v9fs_vfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 808 {
 809         int err;
 810         u32 perm;
 811         struct p9_fid *fid;
 812         struct v9fs_session_info *v9ses;
 813
 814         p9_debug(P9_DEBUG_VFS, "name %s\n", dentry->d_name.name);
 815         err = 0;
 816         v9ses = v9fs_inode2v9ses(dir);
 817         perm = unixmode2p9mode(v9ses, mode | S_IFDIR);
 818         fid = v9fs_create(v9ses, dir, dentry, NULL, perm, P9_OREAD);
 819         if (IS_ERR(fid)) {
 820                 err = PTR_ERR(fid);
 821                 fid = NULL;
 822         } else {
 823                 inc_nlink(dir);
 824                 v9fs_invalidate_inode_attr(dir);
 825         }
 826
 827         if (fid)
 828                 p9_client_clunk(fid);
 829
 830         return err;
 831 }
 832
 833 /**
 834  * v9fs_vfs_lookup - VFS lookup hook to "walk" to a new inode
 835  * @dir:  inode that is being walked from
 836  * @dentry: dentry that is being walked to?
 837  * @nameidata: path data
 838  *
 839  */
 840
 841 struct dentry *v9fs_vfs_lookup(struct inode *dir, struct dentry *dentry,
 842                                       struct nameidata *nameidata)
 843 {
 844         struct dentry *res;
 845         struct super_block *sb;
 846         struct v9fs_session_info *v9ses;
 847         struct p9_fid *dfid, *fid;
 848         struct inode *inode;
 849         char *name;
 850         int result = 0;
 851
 852         p9_debug(P9_DEBUG_VFS, "dir: %p dentry: (%s) %p nameidata: %p\n",
 853                  dir, dentry->d_name.name, dentry, nameidata);
 854
 855         if (dentry->d_name.len > NAME_MAX)
 856                 return ERR_PTR(-ENAMETOOLONG);
 857
 858         sb = dir->i_sb;
 859         v9ses = v9fs_inode2v9ses(dir);
 860         /* We can walk d_parent because we hold the dir->i_mutex */
 861         dfid = v9fs_fid_lookup(dentry->d_parent);
 862         if (IS_ERR(dfid))
 863                 return ERR_CAST(dfid);
 864
 865         name = (char *) dentry->d_name.name;
 866         fid = p9_client_walk(dfid, 1, &name, 1);
 867         if (IS_ERR(fid)) {
 868                 result = PTR_ERR(fid);
 869                 if (result == -ENOENT) {
 870                         inode = NULL;
 871                         goto inst_out;
 872                 }
 873
 874                 return ERR_PTR(result);
 875         }
 876         /*
 877          * Make sure we don't use a wrong inode due to parallel
 878          * unlink. For cached mode create calls request for new
 879          * inode. But with cache disabled, lookup should do this.
 880          */
 881         if (v9ses->cache)
 882                 inode = v9fs_get_inode_from_fid(v9ses, fid, dir->i_sb);
 883         else
 884                 inode = v9fs_get_new_inode_from_fid(v9ses, fid, dir->i_sb);
 885         if (IS_ERR(inode)) {
 886                 result = PTR_ERR(inode);
 887                 inode = NULL;
 888                 goto error;
 889         }
 890         result = v9fs_fid_add(dentry, fid);
 891         if (result < 0)
 892                 goto error_iput;
 893 inst_out:
 894         /*
 895          * If we had a rename on the server and a parallel lookup
 896          * for the new name, then make sure we instantiate with
 897          * the new name. ie look up for a/b, while on server somebody
 898          * moved b under k and client parallely did a lookup for
 899          * k/b.
 900          */
 901         res = d_materialise_unique(dentry, inode);
 902         if (!IS_ERR(res))
 903                 return res;
 904         result = PTR_ERR(res);
 905 error_iput:
 906         iput(inode);
 907 error:
 908         p9_client_clunk(fid);
 909
 910         return ERR_PTR(result);
 911 }
 912
 913 /**
 914  * v9fs_vfs_unlink - VFS unlink hook to delete an inode
 915  * @i:  inode that is being unlinked
 916  * @d: dentry that is being unlinked
 917  *
 918  */
 919
 920 int v9fs_vfs_unlink(struct inode *i, struct dentry *d)
 921 {
 922         return v9fs_remove(i, d, 0);
 923 }
 924
 925 /**
 926  * v9fs_vfs_rmdir - VFS unlink hook to delete a directory
 927  * @i:  inode that is being unlinked
 928  * @d: dentry that is being unlinked
 929  *
 930  */
 931
 932 int v9fs_vfs_rmdir(struct inode *i, struct dentry *d)
 933 {
 934         return v9fs_remove(i, d, AT_REMOVEDIR);
 935 }
 936
 937 /**
 938  * v9fs_vfs_rename - VFS hook to rename an inode
 939  * @old_dir:  old dir inode
 940  * @old_dentry: old dentry
 941  * @new_dir: new dir inode
 942  * @new_dentry: new dentry
 943  *
 944  */
 945
 946 int
 947 v9fs_vfs_rename(struct inode *old_dir, struct dentry *old_dentry,
 948                 struct inode *new_dir, struct dentry *new_dentry)
 949 {
 950         int retval;
 951         struct inode *old_inode;
 952         struct inode *new_inode;
 953         struct v9fs_session_info *v9ses;
 954         struct p9_fid *oldfid;
 955         struct p9_fid *olddirfid;
 956         struct p9_fid *newdirfid;
 957         struct p9_wstat wstat;
 958
 959         p9_debug(P9_DEBUG_VFS, "\n");
 960         retval = 0;
 961         old_inode = old_dentry->d_inode;
 962         new_inode = new_dentry->d_inode;
 963         v9ses = v9fs_inode2v9ses(old_inode);
 964         oldfid = v9fs_fid_lookup(old_dentry);
 965         if (IS_ERR(oldfid))
 966                 return PTR_ERR(oldfid);
 967
 968         olddirfid = v9fs_fid_clone(old_dentry->d_parent);
 969         if (IS_ERR(olddirfid)) {
 970                 retval = PTR_ERR(olddirfid);
 971                 goto done;
 972         }
 973
 974         newdirfid = v9fs_fid_clone(new_dentry->d_parent);
 975         if (IS_ERR(newdirfid)) {
 976                 retval = PTR_ERR(newdirfid);
 977                 goto clunk_olddir;
 978         }
 979
 980         down_write(&v9ses->rename_sem);
 981         if (v9fs_proto_dotl(v9ses)) {
 982                 retval = p9_client_renameat(olddirfid, old_dentry->d_name.name,
 983                                             newdirfid, new_dentry->d_name.name);
 984                 if (retval == -EOPNOTSUPP)
 985                         retval = p9_client_rename(oldfid, newdirfid,
 986                                                   new_dentry->d_name.name);
 987                 if (retval != -EOPNOTSUPP)
 988                         goto clunk_newdir;
 989         }
 990         if (old_dentry->d_parent != new_dentry->d_parent) {
 991                 /*
 992                  * 9P .u can only handle file rename in the same directory
 993                  */
 994
 995                 p9_debug(P9_DEBUG_ERROR, "old dir and new dir are different\n");
 996                 retval = -EXDEV;
 997                 goto clunk_newdir;
 998         }
 999         v9fs_blank_wstat(&wstat);
1000         wstat.muid = v9ses->uname;
1001         wstat.name = (char *) new_dentry->d_name.name;
1002         retval = p9_client_wstat(oldfid, &wstat);
1003
1004 clunk_newdir:
1005         if (!retval) {
1006                 if (new_inode) {
1007                         if (S_ISDIR(new_inode->i_mode))
1008                                 clear_nlink(new_inode);
1009                         else
1010                                 drop_nlink(new_inode);
1011                 }
1012                 if (S_ISDIR(old_inode->i_mode)) {
1013                         if (!new_inode)
1014                                 inc_nlink(new_dir);
1015                         drop_nlink(old_dir);
1016                 }
1017                 v9fs_invalidate_inode_attr(old_inode);
1018                 v9fs_invalidate_inode_attr(old_dir);
1019                 v9fs_invalidate_inode_attr(new_dir);
1020
1021                 /* successful rename */
1022                 d_move(old_dentry, new_dentry);
1023         }
1024         up_write(&v9ses->rename_sem);
1025         p9_client_clunk(newdirfid);
1026
1027 clunk_olddir:
1028         p9_client_clunk(olddirfid);
1029
1030 done:
1031         return retval;
1032 }
1033
1034 /**
1035  * v9fs_vfs_getattr - retrieve file metadata
1036  * @mnt: mount information
1037  * @dentry: file to get attributes on
1038  * @stat: metadata structure to populate
1039  *
1040  */
1041
1042 static int
1043 v9fs_vfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
1044                  struct kstat *stat)
1045 {
1046         int err;
1047         struct v9fs_session_info *v9ses;
1048         struct p9_fid *fid;
1049         struct p9_wstat *st;
1050
1051         p9_debug(P9_DEBUG_VFS, "dentry: %p\n", dentry);
1052         err = -EPERM;
1053         v9ses = v9fs_dentry2v9ses(dentry);
1054         if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE) {
1055                 generic_fillattr(dentry->d_inode, stat);
1056                 return 0;
1057         }
1058         fid = v9fs_fid_lookup(dentry);
1059         if (IS_ERR(fid))
1060                 return PTR_ERR(fid);
1061
1062         st = p9_client_stat(fid);
1063         if (IS_ERR(st))
1064                 return PTR_ERR(st);
1065
1066         v9fs_stat2inode(st, dentry->d_inode, dentry->d_inode->i_sb);
1067         generic_fillattr(dentry->d_inode, stat);
1068
1069         p9stat_free(st);
1070         kfree(st);
1071         return 0;
1072 }
1073
1074 /**
1075  * v9fs_vfs_setattr - set file metadata
1076  * @dentry: file whose metadata to set
1077  * @iattr: metadata assignment structure
1078  *
1079  */
1080
1081 static int v9fs_vfs_setattr(struct dentry *dentry, struct iattr *iattr)
1082 {
1083         int retval;
1084         struct v9fs_session_info *v9ses;
1085         struct p9_fid *fid;
1086         struct p9_wstat wstat;
1087
1088         p9_debug(P9_DEBUG_VFS, "\n");
1089         retval = inode_change_ok(dentry->d_inode, iattr);
1090         if (retval)
1091                 return retval;
1092
1093         retval = -EPERM;
1094         v9ses = v9fs_dentry2v9ses(dentry);
1095         fid = v9fs_fid_lookup(dentry);
1096         if(IS_ERR(fid))
1097                 return PTR_ERR(fid);
1098
1099         v9fs_blank_wstat(&wstat);
1100         if (iattr->ia_valid & ATTR_MODE)
1101                 wstat.mode = unixmode2p9mode(v9ses, iattr->ia_mode);
1102
1103         if (iattr->ia_valid & ATTR_MTIME)
1104                 wstat.mtime = iattr->ia_mtime.tv_sec;
1105
1106         if (iattr->ia_valid & ATTR_ATIME)
1107                 wstat.atime = iattr->ia_atime.tv_sec;
1108
1109         if (iattr->ia_valid & ATTR_SIZE)
1110                 wstat.length = iattr->ia_size;
1111
1112         if (v9fs_proto_dotu(v9ses)) {
1113                 if (iattr->ia_valid & ATTR_UID)
1114                         wstat.n_uid = iattr->ia_uid;
1115
1116                 if (iattr->ia_valid & ATTR_GID)
1117                         wstat.n_gid = iattr->ia_gid;
1118         }
1119
1120         /* Write all dirty data */
1121         if (S_ISREG(dentry->d_inode->i_mode))
1122                 filemap_write_and_wait(dentry->d_inode->i_mapping);
1123
1124         retval = p9_client_wstat(fid, &wstat);
1125         if (retval < 0)
1126                 return retval;
1127
1128         if ((iattr->ia_valid & ATTR_SIZE) &&
1129             iattr->ia_size != i_size_read(dentry->d_inode))
1130                 truncate_setsize(dentry->d_inode, iattr->ia_size);
1131
1132         v9fs_invalidate_inode_attr(dentry->d_inode);
1133
1134         setattr_copy(dentry->d_inode, iattr);
1135         mark_inode_dirty(dentry->d_inode);
1136         return 0;
1137 }
1138
1139 /**
1140  * v9fs_stat2inode - populate an inode structure with mistat info
1141  * @stat: Plan 9 metadata (mistat) structure
1142  * @inode: inode to populate
1143  * @sb: superblock of filesystem
1144  *
1145  */
1146
1147 void
1148 v9fs_stat2inode(struct p9_wstat *stat, struct inode *inode,
1149         struct super_block *sb)
1150 {
1151         umode_t mode;
1152         char ext[32];
1153         char tag_name[14];
1154         unsigned int i_nlink;
1155         struct v9fs_session_info *v9ses = sb->s_fs_info;
1156         struct v9fs_inode *v9inode = V9FS_I(inode);
1157
1158         set_nlink(inode, 1);
1159
1160         inode->i_atime.tv_sec = stat->atime;
1161         inode->i_mtime.tv_sec = stat->mtime;
1162         inode->i_ctime.tv_sec = stat->mtime;
1163
1164         inode->i_uid = v9ses->dfltuid;
1165         inode->i_gid = v9ses->dfltgid;
1166
1167         if (v9fs_proto_dotu(v9ses)) {
1168                 inode->i_uid = stat->n_uid;
1169                 inode->i_gid = stat->n_gid;
1170         }
1171         if ((S_ISREG(inode->i_mode)) || (S_ISDIR(inode->i_mode))) {
1172                 if (v9fs_proto_dotu(v9ses) && (stat->extension[0] != '\0')) {
1173                         /*
1174                          * Hadlink support got added later to
1175                          * to the .u extension. So there can be
1176                          * server out there that doesn't support
1177                          * this even with .u extension. So check
1178                          * for non NULL stat->extension
1179                          */
1180                         strncpy(ext, stat->extension, sizeof(ext));
1181                         /* HARDLINKCOUNT %u */
1182                         sscanf(ext, "%13s %u", tag_name, &i_nlink);
1183                         if (!strncmp(tag_name, "HARDLINKCOUNT", 13))
1184                                 set_nlink(inode, i_nlink);
1185                 }
1186         }
1187         mode = p9mode2perm(v9ses, stat);
1188         mode |= inode->i_mode & ~S_IALLUGO;
1189         inode->i_mode = mode;
1190         i_size_write(inode, stat->length);
1191
1192         /* not real number of blocks, but 512 byte ones ... */
1193         inode->i_blocks = (i_size_read(inode) + 512 - 1) >> 9;
1194         v9inode->cache_validity &= ~V9FS_INO_INVALID_ATTR;
1195 }
1196
1197 /**
1198  * v9fs_qid2ino - convert qid into inode number
1199  * @qid: qid to hash
1200  *
1201  * BUG: potential for inode number collisions?
1202  */
1203
1204 ino_t v9fs_qid2ino(struct p9_qid *qid)
1205 {
1206         u64 path = qid->path + 2;
1207         ino_t i = 0;
1208
1209         if (sizeof(ino_t) == sizeof(path))
1210                 memcpy(&i, &path, sizeof(ino_t));
1211         else
1212                 i = (ino_t) (path ^ (path >> 32));
1213
1214         return i;
1215 }
1216
1217 /**
1218  * v9fs_readlink - read a symlink's location (internal version)
1219  * @dentry: dentry for symlink
1220  * @buffer: buffer to load symlink location into
1221  * @buflen: length of buffer
1222  *
1223  */
1224
1225 static int v9fs_readlink(struct dentry *dentry, char *buffer, int buflen)
1226 {
1227         int retval;
1228
1229         struct v9fs_session_info *v9ses;
1230         struct p9_fid *fid;
1231         struct p9_wstat *st;
1232
1233         p9_debug(P9_DEBUG_VFS, " %s\n", dentry->d_name.name);
1234         retval = -EPERM;
1235         v9ses = v9fs_dentry2v9ses(dentry);
1236         fid = v9fs_fid_lookup(dentry);
1237         if (IS_ERR(fid))
1238                 return PTR_ERR(fid);
1239
1240         if (!v9fs_proto_dotu(v9ses))
1241                 return -EBADF;
1242
1243         st = p9_client_stat(fid);
1244         if (IS_ERR(st))
1245                 return PTR_ERR(st);
1246
1247         if (!(st->mode & P9_DMSYMLINK)) {
1248                 retval = -EINVAL;
1249                 goto done;
1250         }
1251
1252         /* copy extension buffer into buffer */
1253         strncpy(buffer, st->extension, buflen);
1254
1255         p9_debug(P9_DEBUG_VFS, "%s -> %s (%s)\n",
1256                  dentry->d_name.name, st->extension, buffer);
1257
1258         retval = strnlen(buffer, buflen);
1259 done:
1260         p9stat_free(st);
1261         kfree(st);
1262         return retval;
1263 }
1264
1265 /**
1266  * v9fs_vfs_follow_link - follow a symlink path
1267  * @dentry: dentry for symlink
1268  * @nd: nameidata
1269  *
1270  */
1271
1272 static void *v9fs_vfs_follow_link(struct dentry *dentry, struct nameidata *nd)
1273 {
1274         int len = 0;
1275         char *link = __getname();
1276
1277         p9_debug(P9_DEBUG_VFS, "%s\n", dentry->d_name.name);
1278
1279         if (!link)
1280                 link = ERR_PTR(-ENOMEM);
1281         else {
1282                 len = v9fs_readlink(dentry, link, PATH_MAX);
1283
1284                 if (len < 0) {
1285                         __putname(link);
1286                         link = ERR_PTR(len);
1287                 } else
1288                         link[min(len, PATH_MAX-1)] = 0;
1289         }
1290         nd_set_link(nd, link);
1291
1292         return NULL;
1293 }
1294
1295 /**
1296  * v9fs_vfs_put_link - release a symlink path
1297  * @dentry: dentry for symlink
1298  * @nd: nameidata
1299  * @p: unused
1300  *
1301  */
1302
1303 void
1304 v9fs_vfs_put_link(struct dentry *dentry, struct nameidata *nd, void *p)
1305 {
1306         char *s = nd_get_link(nd);
1307
1308         p9_debug(P9_DEBUG_VFS, " %s %s\n",
1309                  dentry->d_name.name, IS_ERR(s) ? "<error>" : s);
1310         if (!IS_ERR(s))
1311                 __putname(s);
1312 }
1313
1314 /**
1315  * v9fs_vfs_mkspecial - create a special file
1316  * @dir: inode to create special file in
1317  * @dentry: dentry to create
1318  * @mode: mode to create special file
1319  * @extension: 9p2000.u format extension string representing special file
1320  *
1321  */
1322
1323 static int v9fs_vfs_mkspecial(struct inode *dir, struct dentry *dentry,
1324         u32 perm, const char *extension)
1325 {
1326         struct p9_fid *fid;
1327         struct v9fs_session_info *v9ses;
1328
1329         v9ses = v9fs_inode2v9ses(dir);
1330         if (!v9fs_proto_dotu(v9ses)) {
1331                 p9_debug(P9_DEBUG_ERROR, "not extended\n");
1332                 return -EPERM;
1333         }
1334
1335         fid = v9fs_create(v9ses, dir, dentry, (char *) extension, perm,
1336                                                                 P9_OREAD);
1337         if (IS_ERR(fid))
1338                 return PTR_ERR(fid);
1339
1340         v9fs_invalidate_inode_attr(dir);
1341         p9_client_clunk(fid);
1342         return 0;
1343 }
1344
1345 /**
1346  * v9fs_vfs_symlink - helper function to create symlinks
1347  * @dir: directory inode containing symlink
1348  * @dentry: dentry for symlink
1349  * @symname: symlink data
1350  *
1351  * See Also: 9P2000.u RFC for more information
1352  *
1353  */
1354
1355 static int
1356 v9fs_vfs_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
1357 {
1358         p9_debug(P9_DEBUG_VFS, " %lu,%s,%s\n",
1359                  dir->i_ino, dentry->d_name.name, symname);
1360
1361         return v9fs_vfs_mkspecial(dir, dentry, P9_DMSYMLINK, symname);
1362 }
1363
1364 /**
1365  * v9fs_vfs_link - create a hardlink
1366  * @old_dentry: dentry for file to link to
1367  * @dir: inode destination for new link
1368  * @dentry: dentry for link
1369  *
1370  */
1371
1372 static int
1373 v9fs_vfs_link(struct dentry *old_dentry, struct inode *dir,
1374               struct dentry *dentry)
1375 {
1376         int retval;
1377         char *name;
1378         struct p9_fid *oldfid;
1379
1380         p9_debug(P9_DEBUG_VFS, " %lu,%s,%s\n",
1381                  dir->i_ino, dentry->d_name.name, old_dentry->d_name.name);
1382
1383         oldfid = v9fs_fid_clone(old_dentry);
1384         if (IS_ERR(oldfid))
1385                 return PTR_ERR(oldfid);
1386
1387         name = __getname();
1388         if (unlikely(!name)) {
1389                 retval = -ENOMEM;
1390                 goto clunk_fid;
1391         }
1392
1393         sprintf(name, "%d\n", oldfid->fid);
1394         retval = v9fs_vfs_mkspecial(dir, dentry, P9_DMLINK, name);
1395         __putname(name);
1396         if (!retval) {
1397                 v9fs_refresh_inode(oldfid, old_dentry->d_inode);
1398                 v9fs_invalidate_inode_attr(dir);
1399         }
1400 clunk_fid:
1401         p9_client_clunk(oldfid);
1402         return retval;
1403 }
1404
1405 /**
1406  * v9fs_vfs_mknod - create a special file
1407  * @dir: inode destination for new link
1408  * @dentry: dentry for file
1409  * @mode: mode for creation
1410  * @rdev: device associated with special file
1411  *
1412  */
1413
1414 static int
1415 v9fs_vfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t rdev)
1416 {
1417         struct v9fs_session_info *v9ses = v9fs_inode2v9ses(dir);
1418         int retval;
1419         char *name;
1420         u32 perm;
1421
1422         p9_debug(P9_DEBUG_VFS, " %lu,%s mode: %hx MAJOR: %u MINOR: %u\n",
1423                  dir->i_ino, dentry->d_name.name, mode,
1424                  MAJOR(rdev), MINOR(rdev));
1425
1426         if (!new_valid_dev(rdev))
1427                 return -EINVAL;
1428
1429         name = __getname();
1430         if (!name)
1431                 return -ENOMEM;
1432         /* build extension */
1433         if (S_ISBLK(mode))
1434                 sprintf(name, "b %u %u", MAJOR(rdev), MINOR(rdev));
1435         else if (S_ISCHR(mode))
1436                 sprintf(name, "c %u %u", MAJOR(rdev), MINOR(rdev));
1437         else if (S_ISFIFO(mode))
1438                 *name = 0;
1439         else if (S_ISSOCK(mode))
1440                 *name = 0;
1441         else {
1442                 __putname(name);
1443                 return -EINVAL;
1444         }
1445
1446         perm = unixmode2p9mode(v9ses, mode);
1447         retval = v9fs_vfs_mkspecial(dir, dentry, perm, name);
1448         __putname(name);
1449
1450         return retval;
1451 }
1452
1453 int v9fs_refresh_inode(struct p9_fid *fid, struct inode *inode)
1454 {
1455         int umode;
1456         dev_t rdev;
1457         loff_t i_size;
1458         struct p9_wstat *st;
1459         struct v9fs_session_info *v9ses;
1460
1461         v9ses = v9fs_inode2v9ses(inode);
1462         st = p9_client_stat(fid);
1463         if (IS_ERR(st))
1464                 return PTR_ERR(st);
1465         /*
1466          * Don't update inode if the file type is different
1467          */
1468         umode = p9mode2unixmode(v9ses, st, &rdev);
1469         if ((inode->i_mode & S_IFMT) != (umode & S_IFMT))
1470                 goto out;
1471
1472         spin_lock(&inode->i_lock);
1473         /*
1474          * We don't want to refresh inode->i_size,
1475          * because we may have cached data
1476          */
1477         i_size = inode->i_size;
1478         v9fs_stat2inode(st, inode, inode->i_sb);
1479         if (v9ses->cache)
1480                 inode->i_size = i_size;
1481         spin_unlock(&inode->i_lock);
1482 out:
1483         p9stat_free(st);
1484         kfree(st);
1485         return 0;
1486 }
1487
1488 static const struct inode_operations v9fs_dir_inode_operations_dotu = {
1489         .create = v9fs_vfs_create,
1490         .lookup = v9fs_vfs_lookup,
1491         .symlink = v9fs_vfs_symlink,
1492         .link = v9fs_vfs_link,
1493         .unlink = v9fs_vfs_unlink,
1494         .mkdir = v9fs_vfs_mkdir,
1495         .rmdir = v9fs_vfs_rmdir,
1496         .mknod = v9fs_vfs_mknod,
1497         .rename = v9fs_vfs_rename,
1498         .getattr = v9fs_vfs_getattr,
1499         .setattr = v9fs_vfs_setattr,
1500 };
1501
1502 static const struct inode_operations v9fs_dir_inode_operations = {
1503         .create = v9fs_vfs_create,
1504         .lookup = v9fs_vfs_lookup,
1505         .unlink = v9fs_vfs_unlink,
1506         .mkdir = v9fs_vfs_mkdir,
1507         .rmdir = v9fs_vfs_rmdir,
1508         .mknod = v9fs_vfs_mknod,
1509         .rename = v9fs_vfs_rename,
1510         .getattr = v9fs_vfs_getattr,
1511         .setattr = v9fs_vfs_setattr,
1512 };
1513
1514 static const struct inode_operations v9fs_file_inode_operations = {
1515         .getattr = v9fs_vfs_getattr,
1516         .setattr = v9fs_vfs_setattr,
1517 };
1518
1519 static const struct inode_operations v9fs_symlink_inode_operations = {
1520         .readlink = generic_readlink,
1521         .follow_link = v9fs_vfs_follow_link,
1522         .put_link = v9fs_vfs_put_link,
1523         .getattr = v9fs_vfs_getattr,
1524         .setattr = v9fs_vfs_setattr,
1525 };
1526