fs/9p/vfs_inode.c

   1 /*
   2  *  linux/fs/9p/vfs_inode.c
   3  *
   4  * This file contains vfs inode ops for the 9P2000 protocol.
   5  *
   6  *  Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
   7  *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
   8  *
   9  *  This program is free software; you can redistribute it and/or modify
  10  *  it under the terms of the GNU General Public License version 2
  11  *  as published by the Free Software Foundation.
  12  *
  13  *  This program is distributed in the hope that it will be useful,
  14  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  *  GNU General Public License for more details.
  17  *
  18  *  You should have received a copy of the GNU General Public License
  19  *  along with this program; if not, write to:
  20  *  Free Software Foundation
  21  *  51 Franklin Street, Fifth Floor
  22  *  Boston, MA  02111-1301  USA
  23  *
  24  */
  25
  26 #include <linux/module.h>
  27 #include <linux/errno.h>
  28 #include <linux/fs.h>
  29 #include <linux/file.h>
  30 #include <linux/pagemap.h>
  31 #include <linux/stat.h>
  32 #include <linux/string.h>
  33 #include <linux/inet.h>
  34 #include <linux/namei.h>
  35 #include <linux/idr.h>
  36 #include <linux/sched.h>
  37 #include <linux/slab.h>
  38 #include <linux/xattr.h>
  39 #include <linux/posix_acl.h>
  40 #include <net/9p/9p.h>
  41 #include <net/9p/client.h>
  42
  43 #include "v9fs.h"
  44 #include "v9fs_vfs.h"
  45 #include "fid.h"
  46 #include "cache.h"
  47 #include "xattr.h"
  48 #include "acl.h"
  49
  50 static const struct inode_operations v9fs_dir_inode_operations;
  51 static const struct inode_operations v9fs_dir_inode_operations_dotu;
  52 static const struct inode_operations v9fs_file_inode_operations;
  53 static const struct inode_operations v9fs_symlink_inode_operations;
  54
  55 /**
  56  * unixmode2p9mode - convert unix mode bits to plan 9
  57  * @v9ses: v9fs session information
  58  * @mode: mode to convert
  59  *
  60  */
  61
  62 static int unixmode2p9mode(struct v9fs_session_info *v9ses, int mode)
  63 {
  64         int res;
  65         res = mode & 0777;
  66         if (S_ISDIR(mode))
  67                 res |= P9_DMDIR;
  68         if (v9fs_proto_dotu(v9ses)) {
  69                 if (S_ISLNK(mode))
  70                         res |= P9_DMSYMLINK;
  71                 if (v9ses->nodev == 0) {
  72                         if (S_ISSOCK(mode))
  73                                 res |= P9_DMSOCKET;
  74                         if (S_ISFIFO(mode))
  75                                 res |= P9_DMNAMEDPIPE;
  76                         if (S_ISBLK(mode))
  77                                 res |= P9_DMDEVICE;
  78                         if (S_ISCHR(mode))
  79                                 res |= P9_DMDEVICE;
  80                 }
  81
  82                 if ((mode & S_ISUID) == S_ISUID)
  83                         res |= P9_DMSETUID;
  84                 if ((mode & S_ISGID) == S_ISGID)
  85                         res |= P9_DMSETGID;
  86                 if ((mode & S_ISVTX) == S_ISVTX)
  87                         res |= P9_DMSETVTX;
  88                 if ((mode & P9_DMLINK))
  89                         res |= P9_DMLINK;
  90         }
  91
  92         return res;
  93 }
  94
  95 /**
  96  * p9mode2unixmode- convert plan9 mode bits to unix mode bits
  97  * @v9ses: v9fs session information
  98  * @mode: mode to convert
  99  *
 100  */
 101
 102 static int p9mode2unixmode(struct v9fs_session_info *v9ses, int mode)
 103 {
 104         int res;
 105
 106         res = mode & 0777;
 107
 108         if ((mode & P9_DMDIR) == P9_DMDIR)
 109                 res |= S_IFDIR;
 110         else if ((mode & P9_DMSYMLINK) && (v9fs_proto_dotu(v9ses)))
 111                 res |= S_IFLNK;
 112         else if ((mode & P9_DMSOCKET) && (v9fs_proto_dotu(v9ses))
 113                  && (v9ses->nodev == 0))
 114                 res |= S_IFSOCK;
 115         else if ((mode & P9_DMNAMEDPIPE) && (v9fs_proto_dotu(v9ses))
 116                  && (v9ses->nodev == 0))
 117                 res |= S_IFIFO;
 118         else if ((mode & P9_DMDEVICE) && (v9fs_proto_dotu(v9ses))
 119                  && (v9ses->nodev == 0))
 120                 res |= S_IFBLK;
 121         else
 122                 res |= S_IFREG;
 123
 124         if (v9fs_proto_dotu(v9ses)) {
 125                 if ((mode & P9_DMSETUID) == P9_DMSETUID)
 126                         res |= S_ISUID;
 127
 128                 if ((mode & P9_DMSETGID) == P9_DMSETGID)
 129                         res |= S_ISGID;
 130
 131                 if ((mode & P9_DMSETVTX) == P9_DMSETVTX)
 132                         res |= S_ISVTX;
 133         }
 134
 135         return res;
 136 }
 137
 138 /**
 139  * v9fs_uflags2omode- convert posix open flags to plan 9 mode bits
 140  * @uflags: flags to convert
 141  * @extended: if .u extensions are active
 142  */
 143
 144 int v9fs_uflags2omode(int uflags, int extended)
 145 {
 146         int ret;
 147
 148         ret = 0;
 149         switch (uflags&3) {
 150         default:
 151         case O_RDONLY:
 152                 ret = P9_OREAD;
 153                 break;
 154
 155         case O_WRONLY:
 156                 ret = P9_OWRITE;
 157                 break;
 158
 159         case O_RDWR:
 160                 ret = P9_ORDWR;
 161                 break;
 162         }
 163
 164         if (uflags & O_TRUNC)
 165                 ret |= P9_OTRUNC;
 166
 167         if (extended) {
 168                 if (uflags & O_EXCL)
 169                         ret |= P9_OEXCL;
 170
 171                 if (uflags & O_APPEND)
 172                         ret |= P9_OAPPEND;
 173         }
 174
 175         return ret;
 176 }
 177
 178 /**
 179  * v9fs_blank_wstat - helper function to setup a 9P stat structure
 180  * @wstat: structure to initialize
 181  *
 182  */
 183
 184 void
 185 v9fs_blank_wstat(struct p9_wstat *wstat)
 186 {
 187         wstat->type = ~0;
 188         wstat->dev = ~0;
 189         wstat->qid.type = ~0;
 190         wstat->qid.version = ~0;
 191         *((long long *)&wstat->qid.path) = ~0;
 192         wstat->mode = ~0;
 193         wstat->atime = ~0;
 194         wstat->mtime = ~0;
 195         wstat->length = ~0;
 196         wstat->name = NULL;
 197         wstat->uid = NULL;
 198         wstat->gid = NULL;
 199         wstat->muid = NULL;
 200         wstat->n_uid = ~0;
 201         wstat->n_gid = ~0;
 202         wstat->n_muid = ~0;
 203         wstat->extension = NULL;
 204 }
 205
 206 #ifdef CONFIG_9P_FSCACHE
 207 /**
 208  * v9fs_alloc_inode - helper function to allocate an inode
 209  * This callback is executed before setting up the inode so that we
 210  * can associate a vcookie with each inode.
 211  *
 212  */
 213
 214 struct inode *v9fs_alloc_inode(struct super_block *sb)
 215 {
 216         struct v9fs_cookie *vcookie;
 217         vcookie = (struct v9fs_cookie *)kmem_cache_alloc(vcookie_cache,
 218                                                          GFP_KERNEL);
 219         if (!vcookie)
 220                 return NULL;
 221
 222         vcookie->fscache = NULL;
 223         vcookie->qid = NULL;
 224         spin_lock_init(&vcookie->lock);
 225         return &vcookie->inode;
 226 }
 227
 228 /**
 229  * v9fs_destroy_inode - destroy an inode
 230  *
 231  */
 232
 233 static void v9fs_i_callback(struct rcu_head *head)
 234 {
 235         struct inode *inode = container_of(head, struct inode, i_rcu);
 236         INIT_LIST_HEAD(&inode->i_dentry);
 237         kmem_cache_free(vcookie_cache, v9fs_inode2cookie(inode));
 238 }
 239
 240 void v9fs_destroy_inode(struct inode *inode)
 241 {
 242         call_rcu(&inode->i_rcu, v9fs_i_callback);
 243 }
 244 #endif
 245
 246 /**
 247  * v9fs_get_inode - helper function to setup an inode
 248  * @sb: superblock
 249  * @mode: mode to setup inode with
 250  *
 251  */
 252
 253 struct inode *v9fs_get_inode(struct super_block *sb, int mode)
 254 {
 255         int err;
 256         struct inode *inode;
 257         struct v9fs_session_info *v9ses = sb->s_fs_info;
 258
 259         P9_DPRINTK(P9_DEBUG_VFS, "super block: %p mode: %o\n", sb, mode);
 260
 261         inode = new_inode(sb);
 262         if (!inode) {
 263                 P9_EPRINTK(KERN_WARNING, "Problem allocating inode\n");
 264                 return ERR_PTR(-ENOMEM);
 265         }
 266
 267         inode_init_owner(inode, NULL, mode);
 268         inode->i_blocks = 0;
 269         inode->i_rdev = 0;
 270         inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 271         inode->i_mapping->a_ops = &v9fs_addr_operations;
 272
 273         switch (mode & S_IFMT) {
 274         case S_IFIFO:
 275         case S_IFBLK:
 276         case S_IFCHR:
 277         case S_IFSOCK:
 278                 if (v9fs_proto_dotl(v9ses)) {
 279                         inode->i_op = &v9fs_file_inode_operations_dotl;
 280                         inode->i_fop = &v9fs_file_operations_dotl;
 281                 } else if (v9fs_proto_dotu(v9ses)) {
 282                         inode->i_op = &v9fs_file_inode_operations;
 283                         inode->i_fop = &v9fs_file_operations;
 284                 } else {
 285                         P9_DPRINTK(P9_DEBUG_ERROR,
 286                                    "special files without extended mode\n");
 287                         err = -EINVAL;
 288                         goto error;
 289                 }
 290                 init_special_inode(inode, inode->i_mode, inode->i_rdev);
 291                 break;
 292         case S_IFREG:
 293                 if (v9fs_proto_dotl(v9ses)) {
 294                         inode->i_op = &v9fs_file_inode_operations_dotl;
 295                         inode->i_fop = &v9fs_file_operations_dotl;
 296                 } else {
 297                         inode->i_op = &v9fs_file_inode_operations;
 298                         inode->i_fop = &v9fs_file_operations;
 299                 }
 300
 301                 break;
 302
 303         case S_IFLNK:
 304                 if (!v9fs_proto_dotu(v9ses) && !v9fs_proto_dotl(v9ses)) {
 305                         P9_DPRINTK(P9_DEBUG_ERROR, "extended modes used with "
 306                                                 "legacy protocol.\n");
 307                         err = -EINVAL;
 308                         goto error;
 309                 }
 310
 311                 if (v9fs_proto_dotl(v9ses))
 312                         inode->i_op = &v9fs_symlink_inode_operations_dotl;
 313                 else
 314                         inode->i_op = &v9fs_symlink_inode_operations;
 315
 316                 break;
 317         case S_IFDIR:
 318                 inc_nlink(inode);
 319                 if (v9fs_proto_dotl(v9ses))
 320                         inode->i_op = &v9fs_dir_inode_operations_dotl;
 321                 else if (v9fs_proto_dotu(v9ses))
 322                         inode->i_op = &v9fs_dir_inode_operations_dotu;
 323                 else
 324                         inode->i_op = &v9fs_dir_inode_operations;
 325
 326                 if (v9fs_proto_dotl(v9ses))
 327                         inode->i_fop = &v9fs_dir_operations_dotl;
 328                 else
 329                         inode->i_fop = &v9fs_dir_operations;
 330
 331                 break;
 332         default:
 333                 P9_DPRINTK(P9_DEBUG_ERROR, "BAD mode 0x%x S_IFMT 0x%x\n",
 334                            mode, mode & S_IFMT);
 335                 err = -EINVAL;
 336                 goto error;
 337         }
 338
 339         return inode;
 340
 341 error:
 342         iput(inode);
 343         return ERR_PTR(err);
 344 }
 345
 346 /*
 347 static struct v9fs_fid*
 348 v9fs_clone_walk(struct v9fs_session_info *v9ses, u32 fid, struct dentry *dentry)
 349 {
 350         int err;
 351         int nfid;
 352         struct v9fs_fid *ret;
 353         struct v9fs_fcall *fcall;
 354
 355         nfid = v9fs_get_idpool(&v9ses->fidpool);
 356         if (nfid < 0) {
 357                 eprintk(KERN_WARNING, "no free fids available\n");
 358                 return ERR_PTR(-ENOSPC);
 359         }
 360
 361         err = v9fs_t_walk(v9ses, fid, nfid, (char *) dentry->d_name.name,
 362                 &fcall);
 363
 364         if (err < 0) {
 365                 if (fcall && fcall->id == RWALK)
 366                         goto clunk_fid;
 367
 368                 PRINT_FCALL_ERROR("walk error", fcall);
 369                 v9fs_put_idpool(nfid, &v9ses->fidpool);
 370                 goto error;
 371         }
 372
 373         kfree(fcall);
 374         fcall = NULL;
 375         ret = v9fs_fid_create(v9ses, nfid);
 376         if (!ret) {
 377                 err = -ENOMEM;
 378                 goto clunk_fid;
 379         }
 380
 381         err = v9fs_fid_insert(ret, dentry);
 382         if (err < 0) {
 383                 v9fs_fid_destroy(ret);
 384                 goto clunk_fid;
 385         }
 386
 387         return ret;
 388
 389 clunk_fid:
 390         v9fs_t_clunk(v9ses, nfid);
 391
 392 error:
 393         kfree(fcall);
 394         return ERR_PTR(err);
 395 }
 396 */
 397
 398
 399 /**
 400  * v9fs_clear_inode - release an inode
 401  * @inode: inode to release
 402  *
 403  */
 404 void v9fs_evict_inode(struct inode *inode)
 405 {
 406         truncate_inode_pages(inode->i_mapping, 0);
 407         end_writeback(inode);
 408         filemap_fdatawrite(inode->i_mapping);
 409
 410 #ifdef CONFIG_9P_FSCACHE
 411         v9fs_cache_inode_put_cookie(inode);
 412 #endif
 413 }
 414
 415 struct inode *
 416 v9fs_inode(struct v9fs_session_info *v9ses, struct p9_fid *fid,
 417         struct super_block *sb)
 418 {
 419         int err, umode;
 420         struct inode *ret = NULL;
 421         struct p9_wstat *st;
 422
 423         st = p9_client_stat(fid);
 424         if (IS_ERR(st))
 425                 return ERR_CAST(st);
 426
 427         umode = p9mode2unixmode(v9ses, st->mode);
 428         ret = v9fs_get_inode(sb, umode);
 429         if (IS_ERR(ret)) {
 430                 err = PTR_ERR(ret);
 431                 goto error;
 432         }
 433
 434         v9fs_stat2inode(st, ret, sb);
 435         ret->i_ino = v9fs_qid2ino(&st->qid);
 436
 437 #ifdef CONFIG_9P_FSCACHE
 438         v9fs_vcookie_set_qid(ret, &st->qid);
 439         v9fs_cache_inode_get_cookie(ret);
 440 #endif
 441         p9stat_free(st);
 442         kfree(st);
 443         return ret;
 444 error:
 445         p9stat_free(st);
 446         kfree(st);
 447         return ERR_PTR(err);
 448 }
 449
 450 /**
 451  * v9fs_remove - helper function to remove files and directories
 452  * @dir: directory inode that is being deleted
 453  * @file:  dentry that is being deleted
 454  * @rmdir: removing a directory
 455  *
 456  */
 457
 458 static int v9fs_remove(struct inode *dir, struct dentry *file, int rmdir)
 459 {
 460         int retval;
 461         struct inode *file_inode;
 462         struct p9_fid *v9fid;
 463
 464         P9_DPRINTK(P9_DEBUG_VFS, "inode: %p dentry: %p rmdir: %d\n", dir, file,
 465                 rmdir);
 466
 467         file_inode = file->d_inode;
 468         v9fid = v9fs_fid_clone(file);
 469         if (IS_ERR(v9fid))
 470                 return PTR_ERR(v9fid);
 471
 472         retval = p9_client_remove(v9fid);
 473         if (!retval)
 474                 drop_nlink(file_inode);
 475         return retval;
 476 }
 477
 478 /**
 479  * v9fs_create - Create a file
 480  * @v9ses: session information
 481  * @dir: directory that dentry is being created in
 482  * @dentry:  dentry that is being created
 483  * @extension: 9p2000.u extension string to support devices, etc.
 484  * @perm: create permissions
 485  * @mode: open mode
 486  *
 487  */
 488 static struct p9_fid *
 489 v9fs_create(struct v9fs_session_info *v9ses, struct inode *dir,
 490                 struct dentry *dentry, char *extension, u32 perm, u8 mode)
 491 {
 492         int err;
 493         char *name;
 494         struct p9_fid *dfid, *ofid, *fid;
 495         struct inode *inode;
 496
 497         P9_DPRINTK(P9_DEBUG_VFS, "name %s\n", dentry->d_name.name);
 498
 499         err = 0;
 500         ofid = NULL;
 501         fid = NULL;
 502         name = (char *) dentry->d_name.name;
 503         dfid = v9fs_fid_lookup(dentry->d_parent);
 504         if (IS_ERR(dfid)) {
 505                 err = PTR_ERR(dfid);
 506                 P9_DPRINTK(P9_DEBUG_VFS, "fid lookup failed %d\n", err);
 507                 return ERR_PTR(err);
 508         }
 509
 510         /* clone a fid to use for creation */
 511         ofid = p9_client_walk(dfid, 0, NULL, 1);
 512         if (IS_ERR(ofid)) {
 513                 err = PTR_ERR(ofid);
 514                 P9_DPRINTK(P9_DEBUG_VFS, "p9_client_walk failed %d\n", err);
 515                 return ERR_PTR(err);
 516         }
 517
 518         err = p9_client_fcreate(ofid, name, perm, mode, extension);
 519         if (err < 0) {
 520                 P9_DPRINTK(P9_DEBUG_VFS, "p9_client_fcreate failed %d\n", err);
 521                 goto error;
 522         }
 523
 524         /* now walk from the parent so we can get unopened fid */
 525         fid = p9_client_walk(dfid, 1, &name, 1);
 526         if (IS_ERR(fid)) {
 527                 err = PTR_ERR(fid);
 528                 P9_DPRINTK(P9_DEBUG_VFS, "p9_client_walk failed %d\n", err);
 529                 fid = NULL;
 530                 goto error;
 531         }
 532
 533         /* instantiate inode and assign the unopened fid to the dentry */
 534         inode = v9fs_inode_from_fid(v9ses, fid, dir->i_sb);
 535         if (IS_ERR(inode)) {
 536                 err = PTR_ERR(inode);
 537                 P9_DPRINTK(P9_DEBUG_VFS, "inode creation failed %d\n", err);
 538                 goto error;
 539         }
 540         d_instantiate(dentry, inode);
 541         err = v9fs_fid_add(dentry, fid);
 542         if (err < 0)
 543                 goto error;
 544
 545         return ofid;
 546
 547 error:
 548         if (ofid)
 549                 p9_client_clunk(ofid);
 550
 551         if (fid)
 552                 p9_client_clunk(fid);
 553
 554         return ERR_PTR(err);
 555 }
 556
 557 /**
 558  * v9fs_vfs_create - VFS hook to create files
 559  * @dir: directory inode that is being created
 560  * @dentry:  dentry that is being deleted
 561  * @mode: create permissions
 562  * @nd: path information
 563  *
 564  */
 565
 566 static int
 567 v9fs_vfs_create(struct inode *dir, struct dentry *dentry, int mode,
 568                 struct nameidata *nd)
 569 {
 570         int err;
 571         u32 perm;
 572         int flags;
 573         struct v9fs_session_info *v9ses;
 574         struct p9_fid *fid;
 575         struct file *filp;
 576
 577         err = 0;
 578         fid = NULL;
 579         v9ses = v9fs_inode2v9ses(dir);
 580         perm = unixmode2p9mode(v9ses, mode);
 581         if (nd && nd->flags & LOOKUP_OPEN)
 582                 flags = nd->intent.open.flags - 1;
 583         else
 584                 flags = O_RDWR;
 585
 586         fid = v9fs_create(v9ses, dir, dentry, NULL, perm,
 587                                 v9fs_uflags2omode(flags,
 588                                                 v9fs_proto_dotu(v9ses)));
 589         if (IS_ERR(fid)) {
 590                 err = PTR_ERR(fid);
 591                 fid = NULL;
 592                 goto error;
 593         }
 594
 595         /* if we are opening a file, assign the open fid to the file */
 596         if (nd && nd->flags & LOOKUP_OPEN) {
 597                 filp = lookup_instantiate_filp(nd, dentry, generic_file_open);
 598                 if (IS_ERR(filp)) {
 599                         err = PTR_ERR(filp);
 600                         goto error;
 601                 }
 602
 603                 filp->private_data = fid;
 604         } else
 605                 p9_client_clunk(fid);
 606
 607         return 0;
 608
 609 error:
 610         if (fid)
 611                 p9_client_clunk(fid);
 612
 613         return err;
 614 }
 615
 616 /**
 617  * v9fs_vfs_mkdir - VFS mkdir hook to create a directory
 618  * @dir:  inode that is being unlinked
 619  * @dentry: dentry that is being unlinked
 620  * @mode: mode for new directory
 621  *
 622  */
 623
 624 static int v9fs_vfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 625 {
 626         int err;
 627         u32 perm;
 628         struct v9fs_session_info *v9ses;
 629         struct p9_fid *fid;
 630
 631         P9_DPRINTK(P9_DEBUG_VFS, "name %s\n", dentry->d_name.name);
 632         err = 0;
 633         v9ses = v9fs_inode2v9ses(dir);
 634         perm = unixmode2p9mode(v9ses, mode | S_IFDIR);
 635         fid = v9fs_create(v9ses, dir, dentry, NULL, perm, P9_OREAD);
 636         if (IS_ERR(fid)) {
 637                 err = PTR_ERR(fid);
 638                 fid = NULL;
 639         }
 640
 641         if (fid)
 642                 p9_client_clunk(fid);
 643
 644         return err;
 645 }
 646
 647 /**
 648  * v9fs_vfs_lookup - VFS lookup hook to "walk" to a new inode
 649  * @dir:  inode that is being walked from
 650  * @dentry: dentry that is being walked to?
 651  * @nameidata: path data
 652  *
 653  */
 654
 655 struct dentry *v9fs_vfs_lookup(struct inode *dir, struct dentry *dentry,
 656                                       struct nameidata *nameidata)
 657 {
 658         struct super_block *sb;
 659         struct v9fs_session_info *v9ses;
 660         struct p9_fid *dfid, *fid;
 661         struct inode *inode;
 662         char *name;
 663         int result = 0;
 664
 665         P9_DPRINTK(P9_DEBUG_VFS, "dir: %p dentry: (%s) %p nameidata: %p\n",
 666                 dir, dentry->d_name.name, dentry, nameidata);
 667
 668         if (dentry->d_name.len > NAME_MAX)
 669                 return ERR_PTR(-ENAMETOOLONG);
 670
 671         sb = dir->i_sb;
 672         v9ses = v9fs_inode2v9ses(dir);
 673         /* We can walk d_parent because we hold the dir->i_mutex */
 674         dfid = v9fs_fid_lookup(dentry->d_parent);
 675         if (IS_ERR(dfid))
 676                 return ERR_CAST(dfid);
 677
 678         name = (char *) dentry->d_name.name;
 679         fid = p9_client_walk(dfid, 1, &name, 1);
 680         if (IS_ERR(fid)) {
 681                 result = PTR_ERR(fid);
 682                 if (result == -ENOENT) {
 683                         inode = NULL;
 684                         goto inst_out;
 685                 }
 686
 687                 return ERR_PTR(result);
 688         }
 689
 690         inode = v9fs_inode_from_fid(v9ses, fid, dir->i_sb);
 691         if (IS_ERR(inode)) {
 692                 result = PTR_ERR(inode);
 693                 inode = NULL;
 694                 goto error;
 695         }
 696
 697         result = v9fs_fid_add(dentry, fid);
 698         if (result < 0)
 699                 goto error_iput;
 700
 701 inst_out:
 702         d_add(dentry, inode);
 703         return NULL;
 704
 705 error_iput:
 706         iput(inode);
 707 error:
 708         p9_client_clunk(fid);
 709
 710         return ERR_PTR(result);
 711 }
 712
 713 /**
 714  * v9fs_vfs_unlink - VFS unlink hook to delete an inode
 715  * @i:  inode that is being unlinked
 716  * @d: dentry that is being unlinked
 717  *
 718  */
 719
 720 int v9fs_vfs_unlink(struct inode *i, struct dentry *d)
 721 {
 722         return v9fs_remove(i, d, 0);
 723 }
 724
 725 /**
 726  * v9fs_vfs_rmdir - VFS unlink hook to delete a directory
 727  * @i:  inode that is being unlinked
 728  * @d: dentry that is being unlinked
 729  *
 730  */
 731
 732 int v9fs_vfs_rmdir(struct inode *i, struct dentry *d)
 733 {
 734         return v9fs_remove(i, d, 1);
 735 }
 736
 737 /**
 738  * v9fs_vfs_rename - VFS hook to rename an inode
 739  * @old_dir:  old dir inode
 740  * @old_dentry: old dentry
 741  * @new_dir: new dir inode
 742  * @new_dentry: new dentry
 743  *
 744  */
 745
 746 int
 747 v9fs_vfs_rename(struct inode *old_dir, struct dentry *old_dentry,
 748                 struct inode *new_dir, struct dentry *new_dentry)
 749 {
 750         struct inode *old_inode;
 751         struct v9fs_session_info *v9ses;
 752         struct p9_fid *oldfid;
 753         struct p9_fid *olddirfid;
 754         struct p9_fid *newdirfid;
 755         struct p9_wstat wstat;
 756         int retval;
 757
 758         P9_DPRINTK(P9_DEBUG_VFS, "\n");
 759         retval = 0;
 760         old_inode = old_dentry->d_inode;
 761         v9ses = v9fs_inode2v9ses(old_inode);
 762         oldfid = v9fs_fid_lookup(old_dentry);
 763         if (IS_ERR(oldfid))
 764                 return PTR_ERR(oldfid);
 765
 766         olddirfid = v9fs_fid_clone(old_dentry->d_parent);
 767         if (IS_ERR(olddirfid)) {
 768                 retval = PTR_ERR(olddirfid);
 769                 goto done;
 770         }
 771
 772         newdirfid = v9fs_fid_clone(new_dentry->d_parent);
 773         if (IS_ERR(newdirfid)) {
 774                 retval = PTR_ERR(newdirfid);
 775                 goto clunk_olddir;
 776         }
 777
 778         down_write(&v9ses->rename_sem);
 779         if (v9fs_proto_dotl(v9ses)) {
 780                 retval = p9_client_rename(oldfid, newdirfid,
 781                                         (char *) new_dentry->d_name.name);
 782                 if (retval != -ENOSYS)
 783                         goto clunk_newdir;
 784         }
 785         if (old_dentry->d_parent != new_dentry->d_parent) {
 786                 /*
 787                  * 9P .u can only handle file rename in the same directory
 788                  */
 789
 790                 P9_DPRINTK(P9_DEBUG_ERROR,
 791                                 "old dir and new dir are different\n");
 792                 retval = -EXDEV;
 793                 goto clunk_newdir;
 794         }
 795         v9fs_blank_wstat(&wstat);
 796         wstat.muid = v9ses->uname;
 797         wstat.name = (char *) new_dentry->d_name.name;
 798         retval = p9_client_wstat(oldfid, &wstat);
 799
 800 clunk_newdir:
 801         if (!retval)
 802                 /* successful rename */
 803                 d_move(old_dentry, new_dentry);
 804         up_write(&v9ses->rename_sem);
 805         p9_client_clunk(newdirfid);
 806
 807 clunk_olddir:
 808         p9_client_clunk(olddirfid);
 809
 810 done:
 811         return retval;
 812 }
 813
 814 /**
 815  * v9fs_vfs_getattr - retrieve file metadata
 816  * @mnt: mount information
 817  * @dentry: file to get attributes on
 818  * @stat: metadata structure to populate
 819  *
 820  */
 821
 822 static int
 823 v9fs_vfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
 824                  struct kstat *stat)
 825 {
 826         int err;
 827         struct v9fs_session_info *v9ses;
 828         struct p9_fid *fid;
 829         struct p9_wstat *st;
 830
 831         P9_DPRINTK(P9_DEBUG_VFS, "dentry: %p\n", dentry);
 832         err = -EPERM;
 833         v9ses = v9fs_inode2v9ses(dentry->d_inode);
 834         if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
 835                 return simple_getattr(mnt, dentry, stat);
 836
 837         fid = v9fs_fid_lookup(dentry);
 838         if (IS_ERR(fid))
 839                 return PTR_ERR(fid);
 840
 841         st = p9_client_stat(fid);
 842         if (IS_ERR(st))
 843                 return PTR_ERR(st);
 844
 845         v9fs_stat2inode(st, dentry->d_inode, dentry->d_inode->i_sb);
 846                 generic_fillattr(dentry->d_inode, stat);
 847
 848         p9stat_free(st);
 849         kfree(st);
 850         return 0;
 851 }
 852
 853 /**
 854  * v9fs_vfs_setattr - set file metadata
 855  * @dentry: file whose metadata to set
 856  * @iattr: metadata assignment structure
 857  *
 858  */
 859
 860 static int v9fs_vfs_setattr(struct dentry *dentry, struct iattr *iattr)
 861 {
 862         int retval;
 863         struct v9fs_session_info *v9ses;
 864         struct p9_fid *fid;
 865         struct p9_wstat wstat;
 866
 867         P9_DPRINTK(P9_DEBUG_VFS, "\n");
 868         retval = -EPERM;
 869         v9ses = v9fs_inode2v9ses(dentry->d_inode);
 870         fid = v9fs_fid_lookup(dentry);
 871         if(IS_ERR(fid))
 872                 return PTR_ERR(fid);
 873
 874         v9fs_blank_wstat(&wstat);
 875         if (iattr->ia_valid & ATTR_MODE)
 876                 wstat.mode = unixmode2p9mode(v9ses, iattr->ia_mode);
 877
 878         if (iattr->ia_valid & ATTR_MTIME)
 879                 wstat.mtime = iattr->ia_mtime.tv_sec;
 880
 881         if (iattr->ia_valid & ATTR_ATIME)
 882                 wstat.atime = iattr->ia_atime.tv_sec;
 883
 884         if (iattr->ia_valid & ATTR_SIZE)
 885                 wstat.length = iattr->ia_size;
 886
 887         if (v9fs_proto_dotu(v9ses)) {
 888                 if (iattr->ia_valid & ATTR_UID)
 889                         wstat.n_uid = iattr->ia_uid;
 890
 891                 if (iattr->ia_valid & ATTR_GID)
 892                         wstat.n_gid = iattr->ia_gid;
 893         }
 894
 895         retval = p9_client_wstat(fid, &wstat);
 896         if (retval < 0)
 897                 return retval;
 898
 899         if ((iattr->ia_valid & ATTR_SIZE) &&
 900             iattr->ia_size != i_size_read(dentry->d_inode)) {
 901                 retval = vmtruncate(dentry->d_inode, iattr->ia_size);
 902                 if (retval)
 903                         return retval;
 904         }
 905
 906         setattr_copy(dentry->d_inode, iattr);
 907         mark_inode_dirty(dentry->d_inode);
 908         return 0;
 909 }
 910
 911 /**
 912  * v9fs_stat2inode - populate an inode structure with mistat info
 913  * @stat: Plan 9 metadata (mistat) structure
 914  * @inode: inode to populate
 915  * @sb: superblock of filesystem
 916  *
 917  */
 918
 919 void
 920 v9fs_stat2inode(struct p9_wstat *stat, struct inode *inode,
 921         struct super_block *sb)
 922 {
 923         char ext[32];
 924         char tag_name[14];
 925         unsigned int i_nlink;
 926         struct v9fs_session_info *v9ses = sb->s_fs_info;
 927
 928         inode->i_nlink = 1;
 929
 930         inode->i_atime.tv_sec = stat->atime;
 931         inode->i_mtime.tv_sec = stat->mtime;
 932         inode->i_ctime.tv_sec = stat->mtime;
 933
 934         inode->i_uid = v9ses->dfltuid;
 935         inode->i_gid = v9ses->dfltgid;
 936
 937         if (v9fs_proto_dotu(v9ses)) {
 938                 inode->i_uid = stat->n_uid;
 939                 inode->i_gid = stat->n_gid;
 940         }
 941         if ((S_ISREG(inode->i_mode)) || (S_ISDIR(inode->i_mode))) {
 942                 if (v9fs_proto_dotu(v9ses) && (stat->extension[0] != '\0')) {
 943                         /*
 944                          * Hadlink support got added later to
 945                          * to the .u extension. So there can be
 946                          * server out there that doesn't support
 947                          * this even with .u extension. So check
 948                          * for non NULL stat->extension
 949                          */
 950                         strncpy(ext, stat->extension, sizeof(ext));
 951                         /* HARDLINKCOUNT %u */
 952                         sscanf(ext, "%13s %u", tag_name, &i_nlink);
 953                         if (!strncmp(tag_name, "HARDLINKCOUNT", 13))
 954                                 inode->i_nlink = i_nlink;
 955                 }
 956         }
 957         inode->i_mode = p9mode2unixmode(v9ses, stat->mode);
 958         if ((S_ISBLK(inode->i_mode)) || (S_ISCHR(inode->i_mode))) {
 959                 char type = 0;
 960                 int major = -1;
 961                 int minor = -1;
 962
 963                 strncpy(ext, stat->extension, sizeof(ext));
 964                 sscanf(ext, "%c %u %u", &type, &major, &minor);
 965                 switch (type) {
 966                 case 'c':
 967                         inode->i_mode &= ~S_IFBLK;
 968                         inode->i_mode |= S_IFCHR;
 969                         break;
 970                 case 'b':
 971                         break;
 972                 default:
 973                         P9_DPRINTK(P9_DEBUG_ERROR,
 974                                 "Unknown special type %c %s\n", type,
 975                                 stat->extension);
 976                 };
 977                 inode->i_rdev = MKDEV(major, minor);
 978                 init_special_inode(inode, inode->i_mode, inode->i_rdev);
 979         } else
 980                 inode->i_rdev = 0;
 981
 982         i_size_write(inode, stat->length);
 983
 984         /* not real number of blocks, but 512 byte ones ... */
 985         inode->i_blocks = (i_size_read(inode) + 512 - 1) >> 9;
 986 }
 987
 988 /**
 989  * v9fs_qid2ino - convert qid into inode number
 990  * @qid: qid to hash
 991  *
 992  * BUG: potential for inode number collisions?
 993  */
 994
 995 ino_t v9fs_qid2ino(struct p9_qid *qid)
 996 {
 997         u64 path = qid->path + 2;
 998         ino_t i = 0;
 999
1000         if (sizeof(ino_t) == sizeof(path))
1001                 memcpy(&i, &path, sizeof(ino_t));
1002         else
1003                 i = (ino_t) (path ^ (path >> 32));
1004
1005         return i;
1006 }
1007
1008 /**
1009  * v9fs_readlink - read a symlink's location (internal version)
1010  * @dentry: dentry for symlink
1011  * @buffer: buffer to load symlink location into
1012  * @buflen: length of buffer
1013  *
1014  */
1015
1016 static int v9fs_readlink(struct dentry *dentry, char *buffer, int buflen)
1017 {
1018         int retval;
1019
1020         struct v9fs_session_info *v9ses;
1021         struct p9_fid *fid;
1022         struct p9_wstat *st;
1023
1024         P9_DPRINTK(P9_DEBUG_VFS, " %s\n", dentry->d_name.name);
1025         retval = -EPERM;
1026         v9ses = v9fs_inode2v9ses(dentry->d_inode);
1027         fid = v9fs_fid_lookup(dentry);
1028         if (IS_ERR(fid))
1029                 return PTR_ERR(fid);
1030
1031         if (!v9fs_proto_dotu(v9ses))
1032                 return -EBADF;
1033
1034         st = p9_client_stat(fid);
1035         if (IS_ERR(st))
1036                 return PTR_ERR(st);
1037
1038         if (!(st->mode & P9_DMSYMLINK)) {
1039                 retval = -EINVAL;
1040                 goto done;
1041         }
1042
1043         /* copy extension buffer into buffer */
1044         strncpy(buffer, st->extension, buflen);
1045
1046         P9_DPRINTK(P9_DEBUG_VFS,
1047                 "%s -> %s (%s)\n", dentry->d_name.name, st->extension, buffer);
1048
1049         retval = strnlen(buffer, buflen);
1050 done:
1051         p9stat_free(st);
1052         kfree(st);
1053         return retval;
1054 }
1055
1056 /**
1057  * v9fs_vfs_follow_link - follow a symlink path
1058  * @dentry: dentry for symlink
1059  * @nd: nameidata
1060  *
1061  */
1062
1063 static void *v9fs_vfs_follow_link(struct dentry *dentry, struct nameidata *nd)
1064 {
1065         int len = 0;
1066         char *link = __getname();
1067
1068         P9_DPRINTK(P9_DEBUG_VFS, "%s n", dentry->d_name.name);
1069
1070         if (!link)
1071                 link = ERR_PTR(-ENOMEM);
1072         else {
1073                 len = v9fs_readlink(dentry, link, PATH_MAX);
1074
1075                 if (len < 0) {
1076                         __putname(link);
1077                         link = ERR_PTR(len);
1078                 } else
1079                         link[min(len, PATH_MAX-1)] = 0;
1080         }
1081         nd_set_link(nd, link);
1082
1083         return NULL;
1084 }
1085
1086 /**
1087  * v9fs_vfs_put_link - release a symlink path
1088  * @dentry: dentry for symlink
1089  * @nd: nameidata
1090  * @p: unused
1091  *
1092  */
1093
1094 void
1095 v9fs_vfs_put_link(struct dentry *dentry, struct nameidata *nd, void *p)
1096 {
1097         char *s = nd_get_link(nd);
1098
1099         P9_DPRINTK(P9_DEBUG_VFS, " %s %s\n", dentry->d_name.name,
1100                 IS_ERR(s) ? "<error>" : s);
1101         if (!IS_ERR(s))
1102                 __putname(s);
1103 }
1104
1105 /**
1106  * v9fs_vfs_mkspecial - create a special file
1107  * @dir: inode to create special file in
1108  * @dentry: dentry to create
1109  * @mode: mode to create special file
1110  * @extension: 9p2000.u format extension string representing special file
1111  *
1112  */
1113
1114 static int v9fs_vfs_mkspecial(struct inode *dir, struct dentry *dentry,
1115         int mode, const char *extension)
1116 {
1117         u32 perm;
1118         struct v9fs_session_info *v9ses;
1119         struct p9_fid *fid;
1120
1121         v9ses = v9fs_inode2v9ses(dir);
1122         if (!v9fs_proto_dotu(v9ses)) {
1123                 P9_DPRINTK(P9_DEBUG_ERROR, "not extended\n");
1124                 return -EPERM;
1125         }
1126
1127         perm = unixmode2p9mode(v9ses, mode);
1128         fid = v9fs_create(v9ses, dir, dentry, (char *) extension, perm,
1129                                                                 P9_OREAD);
1130         if (IS_ERR(fid))
1131                 return PTR_ERR(fid);
1132
1133         p9_client_clunk(fid);
1134         return 0;
1135 }
1136
1137 /**
1138  * v9fs_vfs_symlink - helper function to create symlinks
1139  * @dir: directory inode containing symlink
1140  * @dentry: dentry for symlink
1141  * @symname: symlink data
1142  *
1143  * See Also: 9P2000.u RFC for more information
1144  *
1145  */
1146
1147 static int
1148 v9fs_vfs_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
1149 {
1150         P9_DPRINTK(P9_DEBUG_VFS, " %lu,%s,%s\n", dir->i_ino,
1151                                         dentry->d_name.name, symname);
1152
1153         return v9fs_vfs_mkspecial(dir, dentry, S_IFLNK, symname);
1154 }
1155
1156 /**
1157  * v9fs_vfs_link - create a hardlink
1158  * @old_dentry: dentry for file to link to
1159  * @dir: inode destination for new link
1160  * @dentry: dentry for link
1161  *
1162  */
1163
1164 static int
1165 v9fs_vfs_link(struct dentry *old_dentry, struct inode *dir,
1166               struct dentry *dentry)
1167 {
1168         int retval;
1169         struct p9_fid *oldfid;
1170         char *name;
1171
1172         P9_DPRINTK(P9_DEBUG_VFS,
1173                 " %lu,%s,%s\n", dir->i_ino, dentry->d_name.name,
1174                 old_dentry->d_name.name);
1175
1176         oldfid = v9fs_fid_clone(old_dentry);
1177         if (IS_ERR(oldfid))
1178                 return PTR_ERR(oldfid);
1179
1180         name = __getname();
1181         if (unlikely(!name)) {
1182                 retval = -ENOMEM;
1183                 goto clunk_fid;
1184         }
1185
1186         sprintf(name, "%d\n", oldfid->fid);
1187         retval = v9fs_vfs_mkspecial(dir, dentry, P9_DMLINK, name);
1188         __putname(name);
1189
1190 clunk_fid:
1191         p9_client_clunk(oldfid);
1192         return retval;
1193 }
1194
1195 /**
1196  * v9fs_vfs_mknod - create a special file
1197  * @dir: inode destination for new link
1198  * @dentry: dentry for file
1199  * @mode: mode for creation
1200  * @rdev: device associated with special file
1201  *
1202  */
1203
1204 static int
1205 v9fs_vfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t rdev)
1206 {
1207         int retval;
1208         char *name;
1209
1210         P9_DPRINTK(P9_DEBUG_VFS,
1211                 " %lu,%s mode: %x MAJOR: %u MINOR: %u\n", dir->i_ino,
1212                 dentry->d_name.name, mode, MAJOR(rdev), MINOR(rdev));
1213
1214         if (!new_valid_dev(rdev))
1215                 return -EINVAL;
1216
1217         name = __getname();
1218         if (!name)
1219                 return -ENOMEM;
1220         /* build extension */
1221         if (S_ISBLK(mode))
1222                 sprintf(name, "b %u %u", MAJOR(rdev), MINOR(rdev));
1223         else if (S_ISCHR(mode))
1224                 sprintf(name, "c %u %u", MAJOR(rdev), MINOR(rdev));
1225         else if (S_ISFIFO(mode))
1226                 *name = 0;
1227         else if (S_ISSOCK(mode))
1228                 *name = 0;
1229         else {
1230                 __putname(name);
1231                 return -EINVAL;
1232         }
1233
1234         retval = v9fs_vfs_mkspecial(dir, dentry, mode, name);
1235         __putname(name);
1236
1237         return retval;
1238 }
1239
1240 static const struct inode_operations v9fs_dir_inode_operations_dotu = {
1241         .create = v9fs_vfs_create,
1242         .lookup = v9fs_vfs_lookup,
1243         .symlink = v9fs_vfs_symlink,
1244         .link = v9fs_vfs_link,
1245         .unlink = v9fs_vfs_unlink,
1246         .mkdir = v9fs_vfs_mkdir,
1247         .rmdir = v9fs_vfs_rmdir,
1248         .mknod = v9fs_vfs_mknod,
1249         .rename = v9fs_vfs_rename,
1250         .getattr = v9fs_vfs_getattr,
1251         .setattr = v9fs_vfs_setattr,
1252 };
1253
1254 static const struct inode_operations v9fs_dir_inode_operations = {
1255         .create = v9fs_vfs_create,
1256         .lookup = v9fs_vfs_lookup,
1257         .unlink = v9fs_vfs_unlink,
1258         .mkdir = v9fs_vfs_mkdir,
1259         .rmdir = v9fs_vfs_rmdir,
1260         .mknod = v9fs_vfs_mknod,
1261         .rename = v9fs_vfs_rename,
1262         .getattr = v9fs_vfs_getattr,
1263         .setattr = v9fs_vfs_setattr,
1264 };
1265
1266 static const struct inode_operations v9fs_file_inode_operations = {
1267         .getattr = v9fs_vfs_getattr,
1268         .setattr = v9fs_vfs_setattr,
1269 };
1270
1271 static const struct inode_operations v9fs_symlink_inode_operations = {
1272         .readlink = generic_readlink,
1273         .follow_link = v9fs_vfs_follow_link,
1274         .put_link = v9fs_vfs_put_link,
1275         .getattr = v9fs_vfs_getattr,
1276         .setattr = v9fs_vfs_setattr,
1277 };
1278