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                         if (v9ses->cache)
 296                                 inode->i_fop =
 297                                         &v9fs_cached_file_operations_dotl;
 298                         else
 299                                 inode->i_fop = &v9fs_file_operations_dotl;
 300                 } else {
 301                         inode->i_op = &v9fs_file_inode_operations;
 302                         if (v9ses->cache)
 303                                 inode->i_fop = &v9fs_cached_file_operations;
 304                         else
 305                                 inode->i_fop = &v9fs_file_operations;
 306                 }
 307
 308                 break;
 309
 310         case S_IFLNK:
 311                 if (!v9fs_proto_dotu(v9ses) && !v9fs_proto_dotl(v9ses)) {
 312                         P9_DPRINTK(P9_DEBUG_ERROR, "extended modes used with "
 313                                                 "legacy protocol.\n");
 314                         err = -EINVAL;
 315                         goto error;
 316                 }
 317
 318                 if (v9fs_proto_dotl(v9ses))
 319                         inode->i_op = &v9fs_symlink_inode_operations_dotl;
 320                 else
 321                         inode->i_op = &v9fs_symlink_inode_operations;
 322
 323                 break;
 324         case S_IFDIR:
 325                 inc_nlink(inode);
 326                 if (v9fs_proto_dotl(v9ses))
 327                         inode->i_op = &v9fs_dir_inode_operations_dotl;
 328                 else if (v9fs_proto_dotu(v9ses))
 329                         inode->i_op = &v9fs_dir_inode_operations_dotu;
 330                 else
 331                         inode->i_op = &v9fs_dir_inode_operations;
 332
 333                 if (v9fs_proto_dotl(v9ses))
 334                         inode->i_fop = &v9fs_dir_operations_dotl;
 335                 else
 336                         inode->i_fop = &v9fs_dir_operations;
 337
 338                 break;
 339         default:
 340                 P9_DPRINTK(P9_DEBUG_ERROR, "BAD mode 0x%x S_IFMT 0x%x\n",
 341                            mode, mode & S_IFMT);
 342                 err = -EINVAL;
 343                 goto error;
 344         }
 345
 346         return inode;
 347
 348 error:
 349         iput(inode);
 350         return ERR_PTR(err);
 351 }
 352
 353 /*
 354 static struct v9fs_fid*
 355 v9fs_clone_walk(struct v9fs_session_info *v9ses, u32 fid, struct dentry *dentry)
 356 {
 357         int err;
 358         int nfid;
 359         struct v9fs_fid *ret;
 360         struct v9fs_fcall *fcall;
 361
 362         nfid = v9fs_get_idpool(&v9ses->fidpool);
 363         if (nfid < 0) {
 364                 eprintk(KERN_WARNING, "no free fids available\n");
 365                 return ERR_PTR(-ENOSPC);
 366         }
 367
 368         err = v9fs_t_walk(v9ses, fid, nfid, (char *) dentry->d_name.name,
 369                 &fcall);
 370
 371         if (err < 0) {
 372                 if (fcall && fcall->id == RWALK)
 373                         goto clunk_fid;
 374
 375                 PRINT_FCALL_ERROR("walk error", fcall);
 376                 v9fs_put_idpool(nfid, &v9ses->fidpool);
 377                 goto error;
 378         }
 379
 380         kfree(fcall);
 381         fcall = NULL;
 382         ret = v9fs_fid_create(v9ses, nfid);
 383         if (!ret) {
 384                 err = -ENOMEM;
 385                 goto clunk_fid;
 386         }
 387
 388         err = v9fs_fid_insert(ret, dentry);
 389         if (err < 0) {
 390                 v9fs_fid_destroy(ret);
 391                 goto clunk_fid;
 392         }
 393
 394         return ret;
 395
 396 clunk_fid:
 397         v9fs_t_clunk(v9ses, nfid);
 398
 399 error:
 400         kfree(fcall);
 401         return ERR_PTR(err);
 402 }
 403 */
 404
 405
 406 /**
 407  * v9fs_clear_inode - release an inode
 408  * @inode: inode to release
 409  *
 410  */
 411 void v9fs_evict_inode(struct inode *inode)
 412 {
 413         truncate_inode_pages(inode->i_mapping, 0);
 414         end_writeback(inode);
 415         filemap_fdatawrite(inode->i_mapping);
 416
 417 #ifdef CONFIG_9P_FSCACHE
 418         v9fs_cache_inode_put_cookie(inode);
 419 #endif
 420         /* clunk the fid stashed in inode->i_private */
 421         if (inode->i_private) {
 422                 p9_client_clunk((struct p9_fid *)inode->i_private);
 423                 inode->i_private = NULL;
 424         }
 425 }
 426
 427 struct inode *
 428 v9fs_inode(struct v9fs_session_info *v9ses, struct p9_fid *fid,
 429         struct super_block *sb)
 430 {
 431         int err, umode;
 432         struct inode *ret = NULL;
 433         struct p9_wstat *st;
 434
 435         st = p9_client_stat(fid);
 436         if (IS_ERR(st))
 437                 return ERR_CAST(st);
 438
 439         umode = p9mode2unixmode(v9ses, st->mode);
 440         ret = v9fs_get_inode(sb, umode);
 441         if (IS_ERR(ret)) {
 442                 err = PTR_ERR(ret);
 443                 goto error;
 444         }
 445
 446         v9fs_stat2inode(st, ret, sb);
 447         ret->i_ino = v9fs_qid2ino(&st->qid);
 448
 449 #ifdef CONFIG_9P_FSCACHE
 450         v9fs_vcookie_set_qid(ret, &st->qid);
 451         v9fs_cache_inode_get_cookie(ret);
 452 #endif
 453         p9stat_free(st);
 454         kfree(st);
 455         return ret;
 456 error:
 457         p9stat_free(st);
 458         kfree(st);
 459         return ERR_PTR(err);
 460 }
 461
 462 /**
 463  * v9fs_remove - helper function to remove files and directories
 464  * @dir: directory inode that is being deleted
 465  * @file:  dentry that is being deleted
 466  * @rmdir: removing a directory
 467  *
 468  */
 469
 470 static int v9fs_remove(struct inode *dir, struct dentry *file, int rmdir)
 471 {
 472         int retval;
 473         struct inode *file_inode;
 474         struct p9_fid *v9fid;
 475
 476         P9_DPRINTK(P9_DEBUG_VFS, "inode: %p dentry: %p rmdir: %d\n", dir, file,
 477                 rmdir);
 478
 479         file_inode = file->d_inode;
 480         v9fid = v9fs_fid_clone(file);
 481         if (IS_ERR(v9fid))
 482                 return PTR_ERR(v9fid);
 483
 484         retval = p9_client_remove(v9fid);
 485         if (!retval)
 486                 drop_nlink(file_inode);
 487         return retval;
 488 }
 489
 490 /**
 491  * v9fs_create - Create a file
 492  * @v9ses: session information
 493  * @dir: directory that dentry is being created in
 494  * @dentry:  dentry that is being created
 495  * @extension: 9p2000.u extension string to support devices, etc.
 496  * @perm: create permissions
 497  * @mode: open mode
 498  *
 499  */
 500 static struct p9_fid *
 501 v9fs_create(struct v9fs_session_info *v9ses, struct inode *dir,
 502                 struct dentry *dentry, char *extension, u32 perm, u8 mode)
 503 {
 504         int err;
 505         char *name;
 506         struct p9_fid *dfid, *ofid, *fid;
 507         struct inode *inode;
 508
 509         P9_DPRINTK(P9_DEBUG_VFS, "name %s\n", dentry->d_name.name);
 510
 511         err = 0;
 512         ofid = NULL;
 513         fid = NULL;
 514         name = (char *) dentry->d_name.name;
 515         dfid = v9fs_fid_lookup(dentry->d_parent);
 516         if (IS_ERR(dfid)) {
 517                 err = PTR_ERR(dfid);
 518                 P9_DPRINTK(P9_DEBUG_VFS, "fid lookup failed %d\n", err);
 519                 return ERR_PTR(err);
 520         }
 521
 522         /* clone a fid to use for creation */
 523         ofid = p9_client_walk(dfid, 0, NULL, 1);
 524         if (IS_ERR(ofid)) {
 525                 err = PTR_ERR(ofid);
 526                 P9_DPRINTK(P9_DEBUG_VFS, "p9_client_walk failed %d\n", err);
 527                 return ERR_PTR(err);
 528         }
 529
 530         err = p9_client_fcreate(ofid, name, perm, mode, extension);
 531         if (err < 0) {
 532                 P9_DPRINTK(P9_DEBUG_VFS, "p9_client_fcreate failed %d\n", err);
 533                 goto error;
 534         }
 535
 536         /* now walk from the parent so we can get unopened fid */
 537         fid = p9_client_walk(dfid, 1, &name, 1);
 538         if (IS_ERR(fid)) {
 539                 err = PTR_ERR(fid);
 540                 P9_DPRINTK(P9_DEBUG_VFS, "p9_client_walk failed %d\n", err);
 541                 fid = NULL;
 542                 goto error;
 543         }
 544
 545         /* instantiate inode and assign the unopened fid to the dentry */
 546         inode = v9fs_inode_from_fid(v9ses, fid, dir->i_sb);
 547         if (IS_ERR(inode)) {
 548                 err = PTR_ERR(inode);
 549                 P9_DPRINTK(P9_DEBUG_VFS, "inode creation failed %d\n", err);
 550                 goto error;
 551         }
 552         d_instantiate(dentry, inode);
 553         err = v9fs_fid_add(dentry, fid);
 554         if (err < 0)
 555                 goto error;
 556
 557         return ofid;
 558
 559 error:
 560         if (ofid)
 561                 p9_client_clunk(ofid);
 562
 563         if (fid)
 564                 p9_client_clunk(fid);
 565
 566         return ERR_PTR(err);
 567 }
 568
 569 /**
 570  * v9fs_vfs_create - VFS hook to create files
 571  * @dir: directory inode that is being created
 572  * @dentry:  dentry that is being deleted
 573  * @mode: create permissions
 574  * @nd: path information
 575  *
 576  */
 577
 578 static int
 579 v9fs_vfs_create(struct inode *dir, struct dentry *dentry, int mode,
 580                 struct nameidata *nd)
 581 {
 582         int err;
 583         u32 perm;
 584         int flags;
 585         struct v9fs_session_info *v9ses;
 586         struct p9_fid *fid, *inode_fid;
 587         struct file *filp;
 588
 589         err = 0;
 590         fid = NULL;
 591         v9ses = v9fs_inode2v9ses(dir);
 592         perm = unixmode2p9mode(v9ses, mode);
 593         if (nd && nd->flags & LOOKUP_OPEN)
 594                 flags = nd->intent.open.flags - 1;
 595         else
 596                 flags = O_RDWR;
 597
 598         fid = v9fs_create(v9ses, dir, dentry, NULL, perm,
 599                                 v9fs_uflags2omode(flags,
 600                                                 v9fs_proto_dotu(v9ses)));
 601         if (IS_ERR(fid)) {
 602                 err = PTR_ERR(fid);
 603                 fid = NULL;
 604                 goto error;
 605         }
 606
 607         /* if we are opening a file, assign the open fid to the file */
 608         if (nd && nd->flags & LOOKUP_OPEN) {
 609                 if (v9ses->cache && !dentry->d_inode->i_private) {
 610                         /*
 611                          * clone a fid and add it to inode->i_private
 612                          * we do it during open time instead of
 613                          * page dirty time via write_begin/page_mkwrite
 614                          * because we want write after unlink usecase
 615                          * to work.
 616                          */
 617                         inode_fid = v9fs_writeback_fid(dentry);
 618                         if (IS_ERR(inode_fid)) {
 619                                 err = PTR_ERR(inode_fid);
 620                                 goto error;
 621                         }
 622                         dentry->d_inode->i_private = (void *) inode_fid;
 623                 }
 624                 filp = lookup_instantiate_filp(nd, dentry, generic_file_open);
 625                 if (IS_ERR(filp)) {
 626                         err = PTR_ERR(filp);
 627                         goto error;
 628                 }
 629
 630                 filp->private_data = fid;
 631 #ifdef CONFIG_9P_FSCACHE
 632                 if (v9ses->cache)
 633                         v9fs_cache_inode_set_cookie(dentry->d_inode, filp);
 634 #endif
 635         } else
 636                 p9_client_clunk(fid);
 637
 638         return 0;
 639
 640 error:
 641         if (fid)
 642                 p9_client_clunk(fid);
 643
 644         return err;
 645 }
 646
 647 /**
 648  * v9fs_vfs_mkdir - VFS mkdir hook to create a directory
 649  * @dir:  inode that is being unlinked
 650  * @dentry: dentry that is being unlinked
 651  * @mode: mode for new directory
 652  *
 653  */
 654
 655 static int v9fs_vfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 656 {
 657         int err;
 658         u32 perm;
 659         struct v9fs_session_info *v9ses;
 660         struct p9_fid *fid;
 661
 662         P9_DPRINTK(P9_DEBUG_VFS, "name %s\n", dentry->d_name.name);
 663         err = 0;
 664         v9ses = v9fs_inode2v9ses(dir);
 665         perm = unixmode2p9mode(v9ses, mode | S_IFDIR);
 666         fid = v9fs_create(v9ses, dir, dentry, NULL, perm, P9_OREAD);
 667         if (IS_ERR(fid)) {
 668                 err = PTR_ERR(fid);
 669                 fid = NULL;
 670         }
 671
 672         if (fid)
 673                 p9_client_clunk(fid);
 674
 675         return err;
 676 }
 677
 678 /**
 679  * v9fs_vfs_lookup - VFS lookup hook to "walk" to a new inode
 680  * @dir:  inode that is being walked from
 681  * @dentry: dentry that is being walked to?
 682  * @nameidata: path data
 683  *
 684  */
 685
 686 struct dentry *v9fs_vfs_lookup(struct inode *dir, struct dentry *dentry,
 687                                       struct nameidata *nameidata)
 688 {
 689         struct super_block *sb;
 690         struct v9fs_session_info *v9ses;
 691         struct p9_fid *dfid, *fid;
 692         struct inode *inode;
 693         char *name;
 694         int result = 0;
 695
 696         P9_DPRINTK(P9_DEBUG_VFS, "dir: %p dentry: (%s) %p nameidata: %p\n",
 697                 dir, dentry->d_name.name, dentry, nameidata);
 698
 699         if (dentry->d_name.len > NAME_MAX)
 700                 return ERR_PTR(-ENAMETOOLONG);
 701
 702         sb = dir->i_sb;
 703         v9ses = v9fs_inode2v9ses(dir);
 704         /* We can walk d_parent because we hold the dir->i_mutex */
 705         dfid = v9fs_fid_lookup(dentry->d_parent);
 706         if (IS_ERR(dfid))
 707                 return ERR_CAST(dfid);
 708
 709         name = (char *) dentry->d_name.name;
 710         fid = p9_client_walk(dfid, 1, &name, 1);
 711         if (IS_ERR(fid)) {
 712                 result = PTR_ERR(fid);
 713                 if (result == -ENOENT) {
 714                         inode = NULL;
 715                         goto inst_out;
 716                 }
 717
 718                 return ERR_PTR(result);
 719         }
 720
 721         inode = v9fs_inode_from_fid(v9ses, fid, dir->i_sb);
 722         if (IS_ERR(inode)) {
 723                 result = PTR_ERR(inode);
 724                 inode = NULL;
 725                 goto error;
 726         }
 727
 728         result = v9fs_fid_add(dentry, fid);
 729         if (result < 0)
 730                 goto error_iput;
 731
 732 inst_out:
 733         d_add(dentry, inode);
 734         return NULL;
 735
 736 error_iput:
 737         iput(inode);
 738 error:
 739         p9_client_clunk(fid);
 740
 741         return ERR_PTR(result);
 742 }
 743
 744 /**
 745  * v9fs_vfs_unlink - VFS unlink hook to delete an inode
 746  * @i:  inode that is being unlinked
 747  * @d: dentry that is being unlinked
 748  *
 749  */
 750
 751 int v9fs_vfs_unlink(struct inode *i, struct dentry *d)
 752 {
 753         return v9fs_remove(i, d, 0);
 754 }
 755
 756 /**
 757  * v9fs_vfs_rmdir - VFS unlink hook to delete a directory
 758  * @i:  inode that is being unlinked
 759  * @d: dentry that is being unlinked
 760  *
 761  */
 762
 763 int v9fs_vfs_rmdir(struct inode *i, struct dentry *d)
 764 {
 765         return v9fs_remove(i, d, 1);
 766 }
 767
 768 /**
 769  * v9fs_vfs_rename - VFS hook to rename an inode
 770  * @old_dir:  old dir inode
 771  * @old_dentry: old dentry
 772  * @new_dir: new dir inode
 773  * @new_dentry: new dentry
 774  *
 775  */
 776
 777 int
 778 v9fs_vfs_rename(struct inode *old_dir, struct dentry *old_dentry,
 779                 struct inode *new_dir, struct dentry *new_dentry)
 780 {
 781         struct inode *old_inode;
 782         struct v9fs_session_info *v9ses;
 783         struct p9_fid *oldfid;
 784         struct p9_fid *olddirfid;
 785         struct p9_fid *newdirfid;
 786         struct p9_wstat wstat;
 787         int retval;
 788
 789         P9_DPRINTK(P9_DEBUG_VFS, "\n");
 790         retval = 0;
 791         old_inode = old_dentry->d_inode;
 792         v9ses = v9fs_inode2v9ses(old_inode);
 793         oldfid = v9fs_fid_lookup(old_dentry);
 794         if (IS_ERR(oldfid))
 795                 return PTR_ERR(oldfid);
 796
 797         olddirfid = v9fs_fid_clone(old_dentry->d_parent);
 798         if (IS_ERR(olddirfid)) {
 799                 retval = PTR_ERR(olddirfid);
 800                 goto done;
 801         }
 802
 803         newdirfid = v9fs_fid_clone(new_dentry->d_parent);
 804         if (IS_ERR(newdirfid)) {
 805                 retval = PTR_ERR(newdirfid);
 806                 goto clunk_olddir;
 807         }
 808
 809         down_write(&v9ses->rename_sem);
 810         if (v9fs_proto_dotl(v9ses)) {
 811                 retval = p9_client_rename(oldfid, newdirfid,
 812                                         (char *) new_dentry->d_name.name);
 813                 if (retval != -ENOSYS)
 814                         goto clunk_newdir;
 815         }
 816         if (old_dentry->d_parent != new_dentry->d_parent) {
 817                 /*
 818                  * 9P .u can only handle file rename in the same directory
 819                  */
 820
 821                 P9_DPRINTK(P9_DEBUG_ERROR,
 822                                 "old dir and new dir are different\n");
 823                 retval = -EXDEV;
 824                 goto clunk_newdir;
 825         }
 826         v9fs_blank_wstat(&wstat);
 827         wstat.muid = v9ses->uname;
 828         wstat.name = (char *) new_dentry->d_name.name;
 829         retval = p9_client_wstat(oldfid, &wstat);
 830
 831 clunk_newdir:
 832         if (!retval)
 833                 /* successful rename */
 834                 d_move(old_dentry, new_dentry);
 835         up_write(&v9ses->rename_sem);
 836         p9_client_clunk(newdirfid);
 837
 838 clunk_olddir:
 839         p9_client_clunk(olddirfid);
 840
 841 done:
 842         return retval;
 843 }
 844
 845 /**
 846  * v9fs_vfs_getattr - retrieve file metadata
 847  * @mnt: mount information
 848  * @dentry: file to get attributes on
 849  * @stat: metadata structure to populate
 850  *
 851  */
 852
 853 static int
 854 v9fs_vfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
 855                  struct kstat *stat)
 856 {
 857         int err;
 858         struct v9fs_session_info *v9ses;
 859         struct p9_fid *fid;
 860         struct p9_wstat *st;
 861
 862         P9_DPRINTK(P9_DEBUG_VFS, "dentry: %p\n", dentry);
 863         err = -EPERM;
 864         v9ses = v9fs_inode2v9ses(dentry->d_inode);
 865         if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
 866                 return simple_getattr(mnt, dentry, stat);
 867
 868         fid = v9fs_fid_lookup(dentry);
 869         if (IS_ERR(fid))
 870                 return PTR_ERR(fid);
 871
 872         st = p9_client_stat(fid);
 873         if (IS_ERR(st))
 874                 return PTR_ERR(st);
 875
 876         v9fs_stat2inode(st, dentry->d_inode, dentry->d_inode->i_sb);
 877                 generic_fillattr(dentry->d_inode, stat);
 878
 879         p9stat_free(st);
 880         kfree(st);
 881         return 0;
 882 }
 883
 884 /**
 885  * v9fs_vfs_setattr - set file metadata
 886  * @dentry: file whose metadata to set
 887  * @iattr: metadata assignment structure
 888  *
 889  */
 890
 891 static int v9fs_vfs_setattr(struct dentry *dentry, struct iattr *iattr)
 892 {
 893         int retval;
 894         struct v9fs_session_info *v9ses;
 895         struct p9_fid *fid;
 896         struct p9_wstat wstat;
 897
 898         P9_DPRINTK(P9_DEBUG_VFS, "\n");
 899         retval = -EPERM;
 900         v9ses = v9fs_inode2v9ses(dentry->d_inode);
 901         fid = v9fs_fid_lookup(dentry);
 902         if(IS_ERR(fid))
 903                 return PTR_ERR(fid);
 904
 905         v9fs_blank_wstat(&wstat);
 906         if (iattr->ia_valid & ATTR_MODE)
 907                 wstat.mode = unixmode2p9mode(v9ses, iattr->ia_mode);
 908
 909         if (iattr->ia_valid & ATTR_MTIME)
 910                 wstat.mtime = iattr->ia_mtime.tv_sec;
 911
 912         if (iattr->ia_valid & ATTR_ATIME)
 913                 wstat.atime = iattr->ia_atime.tv_sec;
 914
 915         if (iattr->ia_valid & ATTR_SIZE)
 916                 wstat.length = iattr->ia_size;
 917
 918         if (v9fs_proto_dotu(v9ses)) {
 919                 if (iattr->ia_valid & ATTR_UID)
 920                         wstat.n_uid = iattr->ia_uid;
 921
 922                 if (iattr->ia_valid & ATTR_GID)
 923                         wstat.n_gid = iattr->ia_gid;
 924         }
 925
 926         retval = p9_client_wstat(fid, &wstat);
 927         if (retval < 0)
 928                 return retval;
 929
 930         if ((iattr->ia_valid & ATTR_SIZE) &&
 931             iattr->ia_size != i_size_read(dentry->d_inode)) {
 932                 retval = vmtruncate(dentry->d_inode, iattr->ia_size);
 933                 if (retval)
 934                         return retval;
 935         }
 936
 937         setattr_copy(dentry->d_inode, iattr);
 938         mark_inode_dirty(dentry->d_inode);
 939         return 0;
 940 }
 941
 942 /**
 943  * v9fs_stat2inode - populate an inode structure with mistat info
 944  * @stat: Plan 9 metadata (mistat) structure
 945  * @inode: inode to populate
 946  * @sb: superblock of filesystem
 947  *
 948  */
 949
 950 void
 951 v9fs_stat2inode(struct p9_wstat *stat, struct inode *inode,
 952         struct super_block *sb)
 953 {
 954         char ext[32];
 955         char tag_name[14];
 956         unsigned int i_nlink;
 957         struct v9fs_session_info *v9ses = sb->s_fs_info;
 958
 959         inode->i_nlink = 1;
 960
 961         inode->i_atime.tv_sec = stat->atime;
 962         inode->i_mtime.tv_sec = stat->mtime;
 963         inode->i_ctime.tv_sec = stat->mtime;
 964
 965         inode->i_uid = v9ses->dfltuid;
 966         inode->i_gid = v9ses->dfltgid;
 967
 968         if (v9fs_proto_dotu(v9ses)) {
 969                 inode->i_uid = stat->n_uid;
 970                 inode->i_gid = stat->n_gid;
 971         }
 972         if ((S_ISREG(inode->i_mode)) || (S_ISDIR(inode->i_mode))) {
 973                 if (v9fs_proto_dotu(v9ses) && (stat->extension[0] != '\0')) {
 974                         /*
 975                          * Hadlink support got added later to
 976                          * to the .u extension. So there can be
 977                          * server out there that doesn't support
 978                          * this even with .u extension. So check
 979                          * for non NULL stat->extension
 980                          */
 981                         strncpy(ext, stat->extension, sizeof(ext));
 982                         /* HARDLINKCOUNT %u */
 983                         sscanf(ext, "%13s %u", tag_name, &i_nlink);
 984                         if (!strncmp(tag_name, "HARDLINKCOUNT", 13))
 985                                 inode->i_nlink = i_nlink;
 986                 }
 987         }
 988         inode->i_mode = p9mode2unixmode(v9ses, stat->mode);
 989         if ((S_ISBLK(inode->i_mode)) || (S_ISCHR(inode->i_mode))) {
 990                 char type = 0;
 991                 int major = -1;
 992                 int minor = -1;
 993
 994                 strncpy(ext, stat->extension, sizeof(ext));
 995                 sscanf(ext, "%c %u %u", &type, &major, &minor);
 996                 switch (type) {
 997                 case 'c':
 998                         inode->i_mode &= ~S_IFBLK;
 999                         inode->i_mode |= S_IFCHR;
1000                         break;
1001                 case 'b':
1002                         break;
1003                 default:
1004                         P9_DPRINTK(P9_DEBUG_ERROR,
1005                                 "Unknown special type %c %s\n", type,
1006                                 stat->extension);
1007                 };
1008                 inode->i_rdev = MKDEV(major, minor);
1009                 init_special_inode(inode, inode->i_mode, inode->i_rdev);
1010         } else
1011                 inode->i_rdev = 0;
1012
1013         i_size_write(inode, stat->length);
1014
1015         /* not real number of blocks, but 512 byte ones ... */
1016         inode->i_blocks = (i_size_read(inode) + 512 - 1) >> 9;
1017 }
1018
1019 /**
1020  * v9fs_qid2ino - convert qid into inode number
1021  * @qid: qid to hash
1022  *
1023  * BUG: potential for inode number collisions?
1024  */
1025
1026 ino_t v9fs_qid2ino(struct p9_qid *qid)
1027 {
1028         u64 path = qid->path + 2;
1029         ino_t i = 0;
1030
1031         if (sizeof(ino_t) == sizeof(path))
1032                 memcpy(&i, &path, sizeof(ino_t));
1033         else
1034                 i = (ino_t) (path ^ (path >> 32));
1035
1036         return i;
1037 }
1038
1039 /**
1040  * v9fs_readlink - read a symlink's location (internal version)
1041  * @dentry: dentry for symlink
1042  * @buffer: buffer to load symlink location into
1043  * @buflen: length of buffer
1044  *
1045  */
1046
1047 static int v9fs_readlink(struct dentry *dentry, char *buffer, int buflen)
1048 {
1049         int retval;
1050
1051         struct v9fs_session_info *v9ses;
1052         struct p9_fid *fid;
1053         struct p9_wstat *st;
1054
1055         P9_DPRINTK(P9_DEBUG_VFS, " %s\n", dentry->d_name.name);
1056         retval = -EPERM;
1057         v9ses = v9fs_inode2v9ses(dentry->d_inode);
1058         fid = v9fs_fid_lookup(dentry);
1059         if (IS_ERR(fid))
1060                 return PTR_ERR(fid);
1061
1062         if (!v9fs_proto_dotu(v9ses))
1063                 return -EBADF;
1064
1065         st = p9_client_stat(fid);
1066         if (IS_ERR(st))
1067                 return PTR_ERR(st);
1068
1069         if (!(st->mode & P9_DMSYMLINK)) {
1070                 retval = -EINVAL;
1071                 goto done;
1072         }
1073
1074         /* copy extension buffer into buffer */
1075         strncpy(buffer, st->extension, buflen);
1076
1077         P9_DPRINTK(P9_DEBUG_VFS,
1078                 "%s -> %s (%s)\n", dentry->d_name.name, st->extension, buffer);
1079
1080         retval = strnlen(buffer, buflen);
1081 done:
1082         p9stat_free(st);
1083         kfree(st);
1084         return retval;
1085 }
1086
1087 /**
1088  * v9fs_vfs_follow_link - follow a symlink path
1089  * @dentry: dentry for symlink
1090  * @nd: nameidata
1091  *
1092  */
1093
1094 static void *v9fs_vfs_follow_link(struct dentry *dentry, struct nameidata *nd)
1095 {
1096         int len = 0;
1097         char *link = __getname();
1098
1099         P9_DPRINTK(P9_DEBUG_VFS, "%s n", dentry->d_name.name);
1100
1101         if (!link)
1102                 link = ERR_PTR(-ENOMEM);
1103         else {
1104                 len = v9fs_readlink(dentry, link, PATH_MAX);
1105
1106                 if (len < 0) {
1107                         __putname(link);
1108                         link = ERR_PTR(len);
1109                 } else
1110                         link[min(len, PATH_MAX-1)] = 0;
1111         }
1112         nd_set_link(nd, link);
1113
1114         return NULL;
1115 }
1116
1117 /**
1118  * v9fs_vfs_put_link - release a symlink path
1119  * @dentry: dentry for symlink
1120  * @nd: nameidata
1121  * @p: unused
1122  *
1123  */
1124
1125 void
1126 v9fs_vfs_put_link(struct dentry *dentry, struct nameidata *nd, void *p)
1127 {
1128         char *s = nd_get_link(nd);
1129
1130         P9_DPRINTK(P9_DEBUG_VFS, " %s %s\n", dentry->d_name.name,
1131                 IS_ERR(s) ? "<error>" : s);
1132         if (!IS_ERR(s))
1133                 __putname(s);
1134 }
1135
1136 /**
1137  * v9fs_vfs_mkspecial - create a special file
1138  * @dir: inode to create special file in
1139  * @dentry: dentry to create
1140  * @mode: mode to create special file
1141  * @extension: 9p2000.u format extension string representing special file
1142  *
1143  */
1144
1145 static int v9fs_vfs_mkspecial(struct inode *dir, struct dentry *dentry,
1146         int mode, const char *extension)
1147 {
1148         u32 perm;
1149         struct v9fs_session_info *v9ses;
1150         struct p9_fid *fid;
1151
1152         v9ses = v9fs_inode2v9ses(dir);
1153         if (!v9fs_proto_dotu(v9ses)) {
1154                 P9_DPRINTK(P9_DEBUG_ERROR, "not extended\n");
1155                 return -EPERM;
1156         }
1157
1158         perm = unixmode2p9mode(v9ses, mode);
1159         fid = v9fs_create(v9ses, dir, dentry, (char *) extension, perm,
1160                                                                 P9_OREAD);
1161         if (IS_ERR(fid))
1162                 return PTR_ERR(fid);
1163
1164         p9_client_clunk(fid);
1165         return 0;
1166 }
1167
1168 /**
1169  * v9fs_vfs_symlink - helper function to create symlinks
1170  * @dir: directory inode containing symlink
1171  * @dentry: dentry for symlink
1172  * @symname: symlink data
1173  *
1174  * See Also: 9P2000.u RFC for more information
1175  *
1176  */
1177
1178 static int
1179 v9fs_vfs_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
1180 {
1181         P9_DPRINTK(P9_DEBUG_VFS, " %lu,%s,%s\n", dir->i_ino,
1182                                         dentry->d_name.name, symname);
1183
1184         return v9fs_vfs_mkspecial(dir, dentry, S_IFLNK, symname);
1185 }
1186
1187 /**
1188  * v9fs_vfs_link - create a hardlink
1189  * @old_dentry: dentry for file to link to
1190  * @dir: inode destination for new link
1191  * @dentry: dentry for link
1192  *
1193  */
1194
1195 static int
1196 v9fs_vfs_link(struct dentry *old_dentry, struct inode *dir,
1197               struct dentry *dentry)
1198 {
1199         int retval;
1200         struct p9_fid *oldfid;
1201         char *name;
1202
1203         P9_DPRINTK(P9_DEBUG_VFS,
1204                 " %lu,%s,%s\n", dir->i_ino, dentry->d_name.name,
1205                 old_dentry->d_name.name);
1206
1207         oldfid = v9fs_fid_clone(old_dentry);
1208         if (IS_ERR(oldfid))
1209                 return PTR_ERR(oldfid);
1210
1211         name = __getname();
1212         if (unlikely(!name)) {
1213                 retval = -ENOMEM;
1214                 goto clunk_fid;
1215         }
1216
1217         sprintf(name, "%d\n", oldfid->fid);
1218         retval = v9fs_vfs_mkspecial(dir, dentry, P9_DMLINK, name);
1219         __putname(name);
1220
1221 clunk_fid:
1222         p9_client_clunk(oldfid);
1223         return retval;
1224 }
1225
1226 /**
1227  * v9fs_vfs_mknod - create a special file
1228  * @dir: inode destination for new link
1229  * @dentry: dentry for file
1230  * @mode: mode for creation
1231  * @rdev: device associated with special file
1232  *
1233  */
1234
1235 static int
1236 v9fs_vfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t rdev)
1237 {
1238         int retval;
1239         char *name;
1240
1241         P9_DPRINTK(P9_DEBUG_VFS,
1242                 " %lu,%s mode: %x MAJOR: %u MINOR: %u\n", dir->i_ino,
1243                 dentry->d_name.name, mode, MAJOR(rdev), MINOR(rdev));
1244
1245         if (!new_valid_dev(rdev))
1246                 return -EINVAL;
1247
1248         name = __getname();
1249         if (!name)
1250                 return -ENOMEM;
1251         /* build extension */
1252         if (S_ISBLK(mode))
1253                 sprintf(name, "b %u %u", MAJOR(rdev), MINOR(rdev));
1254         else if (S_ISCHR(mode))
1255                 sprintf(name, "c %u %u", MAJOR(rdev), MINOR(rdev));
1256         else if (S_ISFIFO(mode))
1257                 *name = 0;
1258         else if (S_ISSOCK(mode))
1259                 *name = 0;
1260         else {
1261                 __putname(name);
1262                 return -EINVAL;
1263         }
1264
1265         retval = v9fs_vfs_mkspecial(dir, dentry, mode, name);
1266         __putname(name);
1267
1268         return retval;
1269 }
1270
1271 static const struct inode_operations v9fs_dir_inode_operations_dotu = {
1272         .create = v9fs_vfs_create,
1273         .lookup = v9fs_vfs_lookup,
1274         .symlink = v9fs_vfs_symlink,
1275         .link = v9fs_vfs_link,
1276         .unlink = v9fs_vfs_unlink,
1277         .mkdir = v9fs_vfs_mkdir,
1278         .rmdir = v9fs_vfs_rmdir,
1279         .mknod = v9fs_vfs_mknod,
1280         .rename = v9fs_vfs_rename,
1281         .getattr = v9fs_vfs_getattr,
1282         .setattr = v9fs_vfs_setattr,
1283 };
1284
1285 static const struct inode_operations v9fs_dir_inode_operations = {
1286         .create = v9fs_vfs_create,
1287         .lookup = v9fs_vfs_lookup,
1288         .unlink = v9fs_vfs_unlink,
1289         .mkdir = v9fs_vfs_mkdir,
1290         .rmdir = v9fs_vfs_rmdir,
1291         .mknod = v9fs_vfs_mknod,
1292         .rename = v9fs_vfs_rename,
1293         .getattr = v9fs_vfs_getattr,
1294         .setattr = v9fs_vfs_setattr,
1295 };
1296
1297 static const struct inode_operations v9fs_file_inode_operations = {
1298         .getattr = v9fs_vfs_getattr,
1299         .setattr = v9fs_vfs_setattr,
1300 };
1301
1302 static const struct inode_operations v9fs_symlink_inode_operations = {
1303         .readlink = generic_readlink,
1304         .follow_link = v9fs_vfs_follow_link,
1305         .put_link = v9fs_vfs_put_link,
1306         .getattr = v9fs_vfs_getattr,
1307         .setattr = v9fs_vfs_setattr,
1308 };
1309