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 <net/9p/9p.h>
  38 #include <net/9p/client.h>
  39
  40 #include "v9fs.h"
  41 #include "v9fs_vfs.h"
  42 #include "fid.h"
  43 #include "cache.h"
  44
  45 static const struct inode_operations v9fs_dir_inode_operations;
  46 static const struct inode_operations v9fs_dir_inode_operations_ext;
  47 static const struct inode_operations v9fs_file_inode_operations;
  48 static const struct inode_operations v9fs_symlink_inode_operations;
  49
  50 /**
  51  * unixmode2p9mode - convert unix mode bits to plan 9
  52  * @v9ses: v9fs session information
  53  * @mode: mode to convert
  54  *
  55  */
  56
  57 static int unixmode2p9mode(struct v9fs_session_info *v9ses, int mode)
  58 {
  59         int res;
  60         res = mode & 0777;
  61         if (S_ISDIR(mode))
  62                 res |= P9_DMDIR;
  63         if (v9fs_extended(v9ses)) {
  64                 if (S_ISLNK(mode))
  65                         res |= P9_DMSYMLINK;
  66                 if (v9ses->nodev == 0) {
  67                         if (S_ISSOCK(mode))
  68                                 res |= P9_DMSOCKET;
  69                         if (S_ISFIFO(mode))
  70                                 res |= P9_DMNAMEDPIPE;
  71                         if (S_ISBLK(mode))
  72                                 res |= P9_DMDEVICE;
  73                         if (S_ISCHR(mode))
  74                                 res |= P9_DMDEVICE;
  75                 }
  76
  77                 if ((mode & S_ISUID) == S_ISUID)
  78                         res |= P9_DMSETUID;
  79                 if ((mode & S_ISGID) == S_ISGID)
  80                         res |= P9_DMSETGID;
  81                 if ((mode & S_ISVTX) == S_ISVTX)
  82                         res |= P9_DMSETVTX;
  83                 if ((mode & P9_DMLINK))
  84                         res |= P9_DMLINK;
  85         }
  86
  87         return res;
  88 }
  89
  90 /**
  91  * p9mode2unixmode- convert plan9 mode bits to unix mode bits
  92  * @v9ses: v9fs session information
  93  * @mode: mode to convert
  94  *
  95  */
  96
  97 static int p9mode2unixmode(struct v9fs_session_info *v9ses, int mode)
  98 {
  99         int res;
 100
 101         res = mode & 0777;
 102
 103         if ((mode & P9_DMDIR) == P9_DMDIR)
 104                 res |= S_IFDIR;
 105         else if ((mode & P9_DMSYMLINK) && (v9fs_extended(v9ses)))
 106                 res |= S_IFLNK;
 107         else if ((mode & P9_DMSOCKET) && (v9fs_extended(v9ses))
 108                  && (v9ses->nodev == 0))
 109                 res |= S_IFSOCK;
 110         else if ((mode & P9_DMNAMEDPIPE) && (v9fs_extended(v9ses))
 111                  && (v9ses->nodev == 0))
 112                 res |= S_IFIFO;
 113         else if ((mode & P9_DMDEVICE) && (v9fs_extended(v9ses))
 114                  && (v9ses->nodev == 0))
 115                 res |= S_IFBLK;
 116         else
 117                 res |= S_IFREG;
 118
 119         if (v9fs_extended(v9ses)) {
 120                 if ((mode & P9_DMSETUID) == P9_DMSETUID)
 121                         res |= S_ISUID;
 122
 123                 if ((mode & P9_DMSETGID) == P9_DMSETGID)
 124                         res |= S_ISGID;
 125
 126                 if ((mode & P9_DMSETVTX) == P9_DMSETVTX)
 127                         res |= S_ISVTX;
 128         }
 129
 130         return res;
 131 }
 132
 133 /**
 134  * v9fs_uflags2omode- convert posix open flags to plan 9 mode bits
 135  * @uflags: flags to convert
 136  * @extended: if .u extensions are active
 137  */
 138
 139 int v9fs_uflags2omode(int uflags, int extended)
 140 {
 141         int ret;
 142
 143         ret = 0;
 144         switch (uflags&3) {
 145         default:
 146         case O_RDONLY:
 147                 ret = P9_OREAD;
 148                 break;
 149
 150         case O_WRONLY:
 151                 ret = P9_OWRITE;
 152                 break;
 153
 154         case O_RDWR:
 155                 ret = P9_ORDWR;
 156                 break;
 157         }
 158
 159         if (uflags & O_TRUNC)
 160                 ret |= P9_OTRUNC;
 161
 162         if (extended) {
 163                 if (uflags & O_EXCL)
 164                         ret |= P9_OEXCL;
 165
 166                 if (uflags & O_APPEND)
 167                         ret |= P9_OAPPEND;
 168         }
 169
 170         return ret;
 171 }
 172
 173 /**
 174  * v9fs_blank_wstat - helper function to setup a 9P stat structure
 175  * @wstat: structure to initialize
 176  *
 177  */
 178
 179 static void
 180 v9fs_blank_wstat(struct p9_wstat *wstat)
 181 {
 182         wstat->type = ~0;
 183         wstat->dev = ~0;
 184         wstat->qid.type = ~0;
 185         wstat->qid.version = ~0;
 186         *((long long *)&wstat->qid.path) = ~0;
 187         wstat->mode = ~0;
 188         wstat->atime = ~0;
 189         wstat->mtime = ~0;
 190         wstat->length = ~0;
 191         wstat->name = NULL;
 192         wstat->uid = NULL;
 193         wstat->gid = NULL;
 194         wstat->muid = NULL;
 195         wstat->n_uid = ~0;
 196         wstat->n_gid = ~0;
 197         wstat->n_muid = ~0;
 198         wstat->extension = NULL;
 199 }
 200
 201 #ifdef CONFIG_9P_FSCACHE
 202 /**
 203  * v9fs_alloc_inode - helper function to allocate an inode
 204  * This callback is executed before setting up the inode so that we
 205  * can associate a vcookie with each inode.
 206  *
 207  */
 208
 209 struct inode *v9fs_alloc_inode(struct super_block *sb)
 210 {
 211         struct v9fs_cookie *vcookie;
 212         vcookie = (struct v9fs_cookie *)kmem_cache_alloc(vcookie_cache,
 213                                                          GFP_KERNEL);
 214         if (!vcookie)
 215                 return NULL;
 216
 217         vcookie->fscache = NULL;
 218         vcookie->qid = NULL;
 219         spin_lock_init(&vcookie->lock);
 220         return &vcookie->inode;
 221 }
 222
 223 /**
 224  * v9fs_destroy_inode - destroy an inode
 225  *
 226  */
 227
 228 void v9fs_destroy_inode(struct inode *inode)
 229 {
 230         kmem_cache_free(vcookie_cache, v9fs_inode2cookie(inode));
 231 }
 232 #endif
 233
 234 /**
 235  * v9fs_get_inode - helper function to setup an inode
 236  * @sb: superblock
 237  * @mode: mode to setup inode with
 238  *
 239  */
 240
 241 struct inode *v9fs_get_inode(struct super_block *sb, int mode)
 242 {
 243         int err;
 244         struct inode *inode;
 245         struct v9fs_session_info *v9ses = sb->s_fs_info;
 246
 247         P9_DPRINTK(P9_DEBUG_VFS, "super block: %p mode: %o\n", sb, mode);
 248
 249         inode = new_inode(sb);
 250         if (!inode) {
 251                 P9_EPRINTK(KERN_WARNING, "Problem allocating inode\n");
 252                 return ERR_PTR(-ENOMEM);
 253         }
 254
 255         inode->i_mode = mode;
 256         inode->i_uid = current_fsuid();
 257         inode->i_gid = current_fsgid();
 258         inode->i_blocks = 0;
 259         inode->i_rdev = 0;
 260         inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 261         inode->i_mapping->a_ops = &v9fs_addr_operations;
 262
 263         switch (mode & S_IFMT) {
 264         case S_IFIFO:
 265         case S_IFBLK:
 266         case S_IFCHR:
 267         case S_IFSOCK:
 268                 if (!v9fs_extended(v9ses)) {
 269                         P9_DPRINTK(P9_DEBUG_ERROR,
 270                                    "special files without extended mode\n");
 271                         err = -EINVAL;
 272                         goto error;
 273                 }
 274                 init_special_inode(inode, inode->i_mode, inode->i_rdev);
 275                 break;
 276         case S_IFREG:
 277                 inode->i_op = &v9fs_file_inode_operations;
 278                 inode->i_fop = &v9fs_file_operations;
 279                 break;
 280         case S_IFLNK:
 281                 if (!v9fs_extended(v9ses)) {
 282                         P9_DPRINTK(P9_DEBUG_ERROR,
 283                                    "extended modes used w/o 9P2000.u\n");
 284                         err = -EINVAL;
 285                         goto error;
 286                 }
 287                 inode->i_op = &v9fs_symlink_inode_operations;
 288                 break;
 289         case S_IFDIR:
 290                 inc_nlink(inode);
 291                 if (v9fs_extended(v9ses))
 292                         inode->i_op = &v9fs_dir_inode_operations_ext;
 293                 else
 294                         inode->i_op = &v9fs_dir_inode_operations;
 295                 inode->i_fop = &v9fs_dir_operations;
 296                 break;
 297         default:
 298                 P9_DPRINTK(P9_DEBUG_ERROR, "BAD mode 0x%x S_IFMT 0x%x\n",
 299                            mode, mode & S_IFMT);
 300                 err = -EINVAL;
 301                 goto error;
 302         }
 303
 304         return inode;
 305
 306 error:
 307         iput(inode);
 308         return ERR_PTR(err);
 309 }
 310
 311 /*
 312 static struct v9fs_fid*
 313 v9fs_clone_walk(struct v9fs_session_info *v9ses, u32 fid, struct dentry *dentry)
 314 {
 315         int err;
 316         int nfid;
 317         struct v9fs_fid *ret;
 318         struct v9fs_fcall *fcall;
 319
 320         nfid = v9fs_get_idpool(&v9ses->fidpool);
 321         if (nfid < 0) {
 322                 eprintk(KERN_WARNING, "no free fids available\n");
 323                 return ERR_PTR(-ENOSPC);
 324         }
 325
 326         err = v9fs_t_walk(v9ses, fid, nfid, (char *) dentry->d_name.name,
 327                 &fcall);
 328
 329         if (err < 0) {
 330                 if (fcall && fcall->id == RWALK)
 331                         goto clunk_fid;
 332
 333                 PRINT_FCALL_ERROR("walk error", fcall);
 334                 v9fs_put_idpool(nfid, &v9ses->fidpool);
 335                 goto error;
 336         }
 337
 338         kfree(fcall);
 339         fcall = NULL;
 340         ret = v9fs_fid_create(v9ses, nfid);
 341         if (!ret) {
 342                 err = -ENOMEM;
 343                 goto clunk_fid;
 344         }
 345
 346         err = v9fs_fid_insert(ret, dentry);
 347         if (err < 0) {
 348                 v9fs_fid_destroy(ret);
 349                 goto clunk_fid;
 350         }
 351
 352         return ret;
 353
 354 clunk_fid:
 355         v9fs_t_clunk(v9ses, nfid);
 356
 357 error:
 358         kfree(fcall);
 359         return ERR_PTR(err);
 360 }
 361 */
 362
 363
 364 /**
 365  * v9fs_clear_inode - release an inode
 366  * @inode: inode to release
 367  *
 368  */
 369 void v9fs_clear_inode(struct inode *inode)
 370 {
 371         filemap_fdatawrite(inode->i_mapping);
 372
 373 #ifdef CONFIG_9P_FSCACHE
 374         v9fs_cache_inode_put_cookie(inode);
 375 #endif
 376 }
 377
 378 /**
 379  * v9fs_inode_from_fid - populate an inode by issuing a attribute request
 380  * @v9ses: session information
 381  * @fid: fid to issue attribute request for
 382  * @sb: superblock on which to create inode
 383  *
 384  */
 385
 386 static struct inode *
 387 v9fs_inode_from_fid(struct v9fs_session_info *v9ses, struct p9_fid *fid,
 388         struct super_block *sb)
 389 {
 390         int err, umode;
 391         struct inode *ret;
 392         struct p9_wstat *st;
 393
 394         ret = NULL;
 395         st = p9_client_stat(fid);
 396         if (IS_ERR(st))
 397                 return ERR_CAST(st);
 398
 399         umode = p9mode2unixmode(v9ses, st->mode);
 400         ret = v9fs_get_inode(sb, umode);
 401         if (IS_ERR(ret)) {
 402                 err = PTR_ERR(ret);
 403                 goto error;
 404         }
 405
 406         v9fs_stat2inode(st, ret, sb);
 407         ret->i_ino = v9fs_qid2ino(&st->qid);
 408
 409 #ifdef CONFIG_9P_FSCACHE
 410         v9fs_vcookie_set_qid(ret, &st->qid);
 411         v9fs_cache_inode_get_cookie(ret);
 412 #endif
 413         p9stat_free(st);
 414         kfree(st);
 415
 416         return ret;
 417
 418 error:
 419         p9stat_free(st);
 420         kfree(st);
 421         return ERR_PTR(err);
 422 }
 423
 424 /**
 425  * v9fs_remove - helper function to remove files and directories
 426  * @dir: directory inode that is being deleted
 427  * @file:  dentry that is being deleted
 428  * @rmdir: removing a directory
 429  *
 430  */
 431
 432 static int v9fs_remove(struct inode *dir, struct dentry *file, int rmdir)
 433 {
 434         struct inode *file_inode;
 435         struct v9fs_session_info *v9ses;
 436         struct p9_fid *v9fid;
 437
 438         P9_DPRINTK(P9_DEBUG_VFS, "inode: %p dentry: %p rmdir: %d\n", dir, file,
 439                 rmdir);
 440
 441         file_inode = file->d_inode;
 442         v9ses = v9fs_inode2v9ses(file_inode);
 443         v9fid = v9fs_fid_clone(file);
 444         if (IS_ERR(v9fid))
 445                 return PTR_ERR(v9fid);
 446
 447         return p9_client_remove(v9fid);
 448 }
 449
 450 static int
 451 v9fs_open_created(struct inode *inode, struct file *file)
 452 {
 453         return 0;
 454 }
 455
 456
 457 /**
 458  * v9fs_create - Create a file
 459  * @v9ses: session information
 460  * @dir: directory that dentry is being created in
 461  * @dentry:  dentry that is being created
 462  * @extension: 9p2000.u extension string to support devices, etc.
 463  * @perm: create permissions
 464  * @mode: open mode
 465  *
 466  */
 467 static struct p9_fid *
 468 v9fs_create(struct v9fs_session_info *v9ses, struct inode *dir,
 469                 struct dentry *dentry, char *extension, u32 perm, u8 mode)
 470 {
 471         int err;
 472         char *name;
 473         struct p9_fid *dfid, *ofid, *fid;
 474         struct inode *inode;
 475
 476         P9_DPRINTK(P9_DEBUG_VFS, "name %s\n", dentry->d_name.name);
 477
 478         err = 0;
 479         ofid = NULL;
 480         fid = NULL;
 481         name = (char *) dentry->d_name.name;
 482         dfid = v9fs_fid_clone(dentry->d_parent);
 483         if (IS_ERR(dfid)) {
 484                 err = PTR_ERR(dfid);
 485                 P9_DPRINTK(P9_DEBUG_VFS, "fid clone failed %d\n", err);
 486                 dfid = NULL;
 487                 goto error;
 488         }
 489
 490         /* clone a fid to use for creation */
 491         ofid = p9_client_walk(dfid, 0, NULL, 1);
 492         if (IS_ERR(ofid)) {
 493                 err = PTR_ERR(ofid);
 494                 P9_DPRINTK(P9_DEBUG_VFS, "p9_client_walk failed %d\n", err);
 495                 ofid = NULL;
 496                 goto error;
 497         }
 498
 499         err = p9_client_fcreate(ofid, name, perm, mode, extension);
 500         if (err < 0) {
 501                 P9_DPRINTK(P9_DEBUG_VFS, "p9_client_fcreate failed %d\n", err);
 502                 goto error;
 503         }
 504
 505         /* now walk from the parent so we can get unopened fid */
 506         fid = p9_client_walk(dfid, 1, &name, 0);
 507         if (IS_ERR(fid)) {
 508                 err = PTR_ERR(fid);
 509                 P9_DPRINTK(P9_DEBUG_VFS, "p9_client_walk failed %d\n", err);
 510                 fid = NULL;
 511                 goto error;
 512         } else
 513                 dfid = NULL;
 514
 515         /* instantiate inode and assign the unopened fid to the dentry */
 516         inode = v9fs_inode_from_fid(v9ses, fid, dir->i_sb);
 517         if (IS_ERR(inode)) {
 518                 err = PTR_ERR(inode);
 519                 P9_DPRINTK(P9_DEBUG_VFS, "inode creation failed %d\n", err);
 520                 goto error;
 521         }
 522
 523         if (v9ses->cache)
 524                 dentry->d_op = &v9fs_cached_dentry_operations;
 525         else
 526                 dentry->d_op = &v9fs_dentry_operations;
 527
 528         d_instantiate(dentry, inode);
 529         err = v9fs_fid_add(dentry, fid);
 530         if (err < 0)
 531                 goto error;
 532
 533         return ofid;
 534
 535 error:
 536         if (dfid)
 537                 p9_client_clunk(dfid);
 538
 539         if (ofid)
 540                 p9_client_clunk(ofid);
 541
 542         if (fid)
 543                 p9_client_clunk(fid);
 544
 545         return ERR_PTR(err);
 546 }
 547
 548 /**
 549  * v9fs_vfs_create - VFS hook to create files
 550  * @dir: directory inode that is being created
 551  * @dentry:  dentry that is being deleted
 552  * @mode: create permissions
 553  * @nd: path information
 554  *
 555  */
 556
 557 static int
 558 v9fs_vfs_create(struct inode *dir, struct dentry *dentry, int mode,
 559                 struct nameidata *nd)
 560 {
 561         int err;
 562         u32 perm;
 563         int flags;
 564         struct v9fs_session_info *v9ses;
 565         struct p9_fid *fid;
 566         struct file *filp;
 567
 568         err = 0;
 569         fid = NULL;
 570         v9ses = v9fs_inode2v9ses(dir);
 571         perm = unixmode2p9mode(v9ses, mode);
 572         if (nd && nd->flags & LOOKUP_OPEN)
 573                 flags = nd->intent.open.flags - 1;
 574         else
 575                 flags = O_RDWR;
 576
 577         fid = v9fs_create(v9ses, dir, dentry, NULL, perm,
 578                                 v9fs_uflags2omode(flags, v9fs_extended(v9ses)));
 579         if (IS_ERR(fid)) {
 580                 err = PTR_ERR(fid);
 581                 fid = NULL;
 582                 goto error;
 583         }
 584
 585         /* if we are opening a file, assign the open fid to the file */
 586         if (nd && nd->flags & LOOKUP_OPEN) {
 587                 filp = lookup_instantiate_filp(nd, dentry, v9fs_open_created);
 588                 if (IS_ERR(filp)) {
 589                         err = PTR_ERR(filp);
 590                         goto error;
 591                 }
 592
 593                 filp->private_data = fid;
 594         } else
 595                 p9_client_clunk(fid);
 596
 597         return 0;
 598
 599 error:
 600         if (fid)
 601                 p9_client_clunk(fid);
 602
 603         return err;
 604 }
 605
 606 /**
 607  * v9fs_vfs_mkdir - VFS mkdir hook to create a directory
 608  * @dir:  inode that is being unlinked
 609  * @dentry: dentry that is being unlinked
 610  * @mode: mode for new directory
 611  *
 612  */
 613
 614 static int v9fs_vfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 615 {
 616         int err;
 617         u32 perm;
 618         struct v9fs_session_info *v9ses;
 619         struct p9_fid *fid;
 620
 621         P9_DPRINTK(P9_DEBUG_VFS, "name %s\n", dentry->d_name.name);
 622         err = 0;
 623         v9ses = v9fs_inode2v9ses(dir);
 624         perm = unixmode2p9mode(v9ses, mode | S_IFDIR);
 625         fid = v9fs_create(v9ses, dir, dentry, NULL, perm, P9_OREAD);
 626         if (IS_ERR(fid)) {
 627                 err = PTR_ERR(fid);
 628                 fid = NULL;
 629         }
 630
 631         if (fid)
 632                 p9_client_clunk(fid);
 633
 634         return err;
 635 }
 636
 637 /**
 638  * v9fs_vfs_lookup - VFS lookup hook to "walk" to a new inode
 639  * @dir:  inode that is being walked from
 640  * @dentry: dentry that is being walked to?
 641  * @nameidata: path data
 642  *
 643  */
 644
 645 static struct dentry *v9fs_vfs_lookup(struct inode *dir, struct dentry *dentry,
 646                                       struct nameidata *nameidata)
 647 {
 648         struct super_block *sb;
 649         struct v9fs_session_info *v9ses;
 650         struct p9_fid *dfid, *fid;
 651         struct inode *inode;
 652         char *name;
 653         int result = 0;
 654
 655         P9_DPRINTK(P9_DEBUG_VFS, "dir: %p dentry: (%s) %p nameidata: %p\n",
 656                 dir, dentry->d_name.name, dentry, nameidata);
 657
 658         sb = dir->i_sb;
 659         v9ses = v9fs_inode2v9ses(dir);
 660         dfid = v9fs_fid_lookup(dentry->d_parent);
 661         if (IS_ERR(dfid))
 662                 return ERR_CAST(dfid);
 663
 664         name = (char *) dentry->d_name.name;
 665         fid = p9_client_walk(dfid, 1, &name, 1);
 666         if (IS_ERR(fid)) {
 667                 result = PTR_ERR(fid);
 668                 if (result == -ENOENT) {
 669                         d_add(dentry, NULL);
 670                         return NULL;
 671                 }
 672
 673                 return ERR_PTR(result);
 674         }
 675
 676         inode = v9fs_inode_from_fid(v9ses, fid, dir->i_sb);
 677         if (IS_ERR(inode)) {
 678                 result = PTR_ERR(inode);
 679                 inode = NULL;
 680                 goto error;
 681         }
 682
 683         result = v9fs_fid_add(dentry, fid);
 684         if (result < 0)
 685                 goto error;
 686
 687         if ((fid->qid.version) && (v9ses->cache))
 688                 dentry->d_op = &v9fs_cached_dentry_operations;
 689         else
 690                 dentry->d_op = &v9fs_dentry_operations;
 691
 692         d_add(dentry, inode);
 693         return NULL;
 694
 695 error:
 696         p9_client_clunk(fid);
 697
 698         return ERR_PTR(result);
 699 }
 700
 701 /**
 702  * v9fs_vfs_unlink - VFS unlink hook to delete an inode
 703  * @i:  inode that is being unlinked
 704  * @d: dentry that is being unlinked
 705  *
 706  */
 707
 708 static int v9fs_vfs_unlink(struct inode *i, struct dentry *d)
 709 {
 710         return v9fs_remove(i, d, 0);
 711 }
 712
 713 /**
 714  * v9fs_vfs_rmdir - VFS unlink hook to delete a directory
 715  * @i:  inode that is being unlinked
 716  * @d: dentry that is being unlinked
 717  *
 718  */
 719
 720 static int v9fs_vfs_rmdir(struct inode *i, struct dentry *d)
 721 {
 722         return v9fs_remove(i, d, 1);
 723 }
 724
 725 /**
 726  * v9fs_vfs_rename - VFS hook to rename an inode
 727  * @old_dir:  old dir inode
 728  * @old_dentry: old dentry
 729  * @new_dir: new dir inode
 730  * @new_dentry: new dentry
 731  *
 732  */
 733
 734 static int
 735 v9fs_vfs_rename(struct inode *old_dir, struct dentry *old_dentry,
 736                 struct inode *new_dir, struct dentry *new_dentry)
 737 {
 738         struct inode *old_inode;
 739         struct v9fs_session_info *v9ses;
 740         struct p9_fid *oldfid;
 741         struct p9_fid *olddirfid;
 742         struct p9_fid *newdirfid;
 743         struct p9_wstat wstat;
 744         int retval;
 745
 746         P9_DPRINTK(P9_DEBUG_VFS, "\n");
 747         retval = 0;
 748         old_inode = old_dentry->d_inode;
 749         v9ses = v9fs_inode2v9ses(old_inode);
 750         oldfid = v9fs_fid_lookup(old_dentry);
 751         if (IS_ERR(oldfid))
 752                 return PTR_ERR(oldfid);
 753
 754         olddirfid = v9fs_fid_clone(old_dentry->d_parent);
 755         if (IS_ERR(olddirfid)) {
 756                 retval = PTR_ERR(olddirfid);
 757                 goto done;
 758         }
 759
 760         newdirfid = v9fs_fid_clone(new_dentry->d_parent);
 761         if (IS_ERR(newdirfid)) {
 762                 retval = PTR_ERR(newdirfid);
 763                 goto clunk_olddir;
 764         }
 765
 766         /* 9P can only handle file rename in the same directory */
 767         if (memcmp(&olddirfid->qid, &newdirfid->qid, sizeof(newdirfid->qid))) {
 768                 P9_DPRINTK(P9_DEBUG_ERROR,
 769                                 "old dir and new dir are different\n");
 770                 retval = -EXDEV;
 771                 goto clunk_newdir;
 772         }
 773
 774         v9fs_blank_wstat(&wstat);
 775         wstat.muid = v9ses->uname;
 776         wstat.name = (char *) new_dentry->d_name.name;
 777         retval = p9_client_wstat(oldfid, &wstat);
 778
 779 clunk_newdir:
 780         p9_client_clunk(newdirfid);
 781
 782 clunk_olddir:
 783         p9_client_clunk(olddirfid);
 784
 785 done:
 786         return retval;
 787 }
 788
 789 /**
 790  * v9fs_vfs_getattr - retrieve file metadata
 791  * @mnt: mount information
 792  * @dentry: file to get attributes on
 793  * @stat: metadata structure to populate
 794  *
 795  */
 796
 797 static int
 798 v9fs_vfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
 799                  struct kstat *stat)
 800 {
 801         int err;
 802         struct v9fs_session_info *v9ses;
 803         struct p9_fid *fid;
 804         struct p9_wstat *st;
 805
 806         P9_DPRINTK(P9_DEBUG_VFS, "dentry: %p\n", dentry);
 807         err = -EPERM;
 808         v9ses = v9fs_inode2v9ses(dentry->d_inode);
 809         if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
 810                 return simple_getattr(mnt, dentry, stat);
 811
 812         fid = v9fs_fid_lookup(dentry);
 813         if (IS_ERR(fid))
 814                 return PTR_ERR(fid);
 815
 816         st = p9_client_stat(fid);
 817         if (IS_ERR(st))
 818                 return PTR_ERR(st);
 819
 820         v9fs_stat2inode(st, dentry->d_inode, dentry->d_inode->i_sb);
 821                 generic_fillattr(dentry->d_inode, stat);
 822
 823         kfree(st);
 824         return 0;
 825 }
 826
 827 /**
 828  * v9fs_vfs_setattr - set file metadata
 829  * @dentry: file whose metadata to set
 830  * @iattr: metadata assignment structure
 831  *
 832  */
 833
 834 static int v9fs_vfs_setattr(struct dentry *dentry, struct iattr *iattr)
 835 {
 836         int retval;
 837         struct v9fs_session_info *v9ses;
 838         struct p9_fid *fid;
 839         struct p9_wstat wstat;
 840
 841         P9_DPRINTK(P9_DEBUG_VFS, "\n");
 842         retval = -EPERM;
 843         v9ses = v9fs_inode2v9ses(dentry->d_inode);
 844         fid = v9fs_fid_lookup(dentry);
 845         if(IS_ERR(fid))
 846                 return PTR_ERR(fid);
 847
 848         v9fs_blank_wstat(&wstat);
 849         if (iattr->ia_valid & ATTR_MODE)
 850                 wstat.mode = unixmode2p9mode(v9ses, iattr->ia_mode);
 851
 852         if (iattr->ia_valid & ATTR_MTIME)
 853                 wstat.mtime = iattr->ia_mtime.tv_sec;
 854
 855         if (iattr->ia_valid & ATTR_ATIME)
 856                 wstat.atime = iattr->ia_atime.tv_sec;
 857
 858         if (iattr->ia_valid & ATTR_SIZE)
 859                 wstat.length = iattr->ia_size;
 860
 861         if (v9fs_extended(v9ses)) {
 862                 if (iattr->ia_valid & ATTR_UID)
 863                         wstat.n_uid = iattr->ia_uid;
 864
 865                 if (iattr->ia_valid & ATTR_GID)
 866                         wstat.n_gid = iattr->ia_gid;
 867         }
 868
 869         retval = p9_client_wstat(fid, &wstat);
 870         if (retval >= 0)
 871                 retval = inode_setattr(dentry->d_inode, iattr);
 872
 873         return retval;
 874 }
 875
 876 /**
 877  * v9fs_stat2inode - populate an inode structure with mistat info
 878  * @stat: Plan 9 metadata (mistat) structure
 879  * @inode: inode to populate
 880  * @sb: superblock of filesystem
 881  *
 882  */
 883
 884 void
 885 v9fs_stat2inode(struct p9_wstat *stat, struct inode *inode,
 886         struct super_block *sb)
 887 {
 888         char ext[32];
 889         struct v9fs_session_info *v9ses = sb->s_fs_info;
 890
 891         inode->i_nlink = 1;
 892
 893         inode->i_atime.tv_sec = stat->atime;
 894         inode->i_mtime.tv_sec = stat->mtime;
 895         inode->i_ctime.tv_sec = stat->mtime;
 896
 897         inode->i_uid = v9ses->dfltuid;
 898         inode->i_gid = v9ses->dfltgid;
 899
 900         if (v9fs_extended(v9ses)) {
 901                 inode->i_uid = stat->n_uid;
 902                 inode->i_gid = stat->n_gid;
 903         }
 904
 905         inode->i_mode = p9mode2unixmode(v9ses, stat->mode);
 906         if ((S_ISBLK(inode->i_mode)) || (S_ISCHR(inode->i_mode))) {
 907                 char type = 0;
 908                 int major = -1;
 909                 int minor = -1;
 910
 911                 strncpy(ext, stat->extension, sizeof(ext));
 912                 sscanf(ext, "%c %u %u", &type, &major, &minor);
 913                 switch (type) {
 914                 case 'c':
 915                         inode->i_mode &= ~S_IFBLK;
 916                         inode->i_mode |= S_IFCHR;
 917                         break;
 918                 case 'b':
 919                         break;
 920                 default:
 921                         P9_DPRINTK(P9_DEBUG_ERROR,
 922                                 "Unknown special type %c %s\n", type,
 923                                 stat->extension);
 924                 };
 925                 inode->i_rdev = MKDEV(major, minor);
 926                 init_special_inode(inode, inode->i_mode, inode->i_rdev);
 927         } else
 928                 inode->i_rdev = 0;
 929
 930         i_size_write(inode, stat->length);
 931
 932         /* not real number of blocks, but 512 byte ones ... */
 933         inode->i_blocks = (i_size_read(inode) + 512 - 1) >> 9;
 934 }
 935
 936 /**
 937  * v9fs_qid2ino - convert qid into inode number
 938  * @qid: qid to hash
 939  *
 940  * BUG: potential for inode number collisions?
 941  */
 942
 943 ino_t v9fs_qid2ino(struct p9_qid *qid)
 944 {
 945         u64 path = qid->path + 2;
 946         ino_t i = 0;
 947
 948         if (sizeof(ino_t) == sizeof(path))
 949                 memcpy(&i, &path, sizeof(ino_t));
 950         else
 951                 i = (ino_t) (path ^ (path >> 32));
 952
 953         return i;
 954 }
 955
 956 /**
 957  * v9fs_readlink - read a symlink's location (internal version)
 958  * @dentry: dentry for symlink
 959  * @buffer: buffer to load symlink location into
 960  * @buflen: length of buffer
 961  *
 962  */
 963
 964 static int v9fs_readlink(struct dentry *dentry, char *buffer, int buflen)
 965 {
 966         int retval;
 967
 968         struct v9fs_session_info *v9ses;
 969         struct p9_fid *fid;
 970         struct p9_wstat *st;
 971
 972         P9_DPRINTK(P9_DEBUG_VFS, " %s\n", dentry->d_name.name);
 973         retval = -EPERM;
 974         v9ses = v9fs_inode2v9ses(dentry->d_inode);
 975         fid = v9fs_fid_lookup(dentry);
 976         if (IS_ERR(fid))
 977                 return PTR_ERR(fid);
 978
 979         if (!v9fs_extended(v9ses))
 980                 return -EBADF;
 981
 982         st = p9_client_stat(fid);
 983         if (IS_ERR(st))
 984                 return PTR_ERR(st);
 985
 986         if (!(st->mode & P9_DMSYMLINK)) {
 987                 retval = -EINVAL;
 988                 goto done;
 989         }
 990
 991         /* copy extension buffer into buffer */
 992         strncpy(buffer, st->extension, buflen);
 993
 994         P9_DPRINTK(P9_DEBUG_VFS,
 995                 "%s -> %s (%s)\n", dentry->d_name.name, st->extension, buffer);
 996
 997         retval = strnlen(buffer, buflen);
 998 done:
 999         kfree(st);
1000         return retval;
1001 }
1002
1003 /**
1004  * v9fs_vfs_readlink - read a symlink's location
1005  * @dentry: dentry for symlink
1006  * @buffer: buffer to load symlink location into
1007  * @buflen: length of buffer
1008  *
1009  */
1010
1011 static int v9fs_vfs_readlink(struct dentry *dentry, char __user * buffer,
1012                              int buflen)
1013 {
1014         int retval;
1015         int ret;
1016         char *link = __getname();
1017
1018         if (unlikely(!link))
1019                 return -ENOMEM;
1020
1021         if (buflen > PATH_MAX)
1022                 buflen = PATH_MAX;
1023
1024         P9_DPRINTK(P9_DEBUG_VFS, " dentry: %s (%p)\n", dentry->d_name.name,
1025                                                                         dentry);
1026
1027         retval = v9fs_readlink(dentry, link, buflen);
1028
1029         if (retval > 0) {
1030                 if ((ret = copy_to_user(buffer, link, retval)) != 0) {
1031                         P9_DPRINTK(P9_DEBUG_ERROR,
1032                                         "problem copying to user: %d\n", ret);
1033                         retval = ret;
1034                 }
1035         }
1036
1037         __putname(link);
1038         return retval;
1039 }
1040
1041 /**
1042  * v9fs_vfs_follow_link - follow a symlink path
1043  * @dentry: dentry for symlink
1044  * @nd: nameidata
1045  *
1046  */
1047
1048 static void *v9fs_vfs_follow_link(struct dentry *dentry, struct nameidata *nd)
1049 {
1050         int len = 0;
1051         char *link = __getname();
1052
1053         P9_DPRINTK(P9_DEBUG_VFS, "%s n", dentry->d_name.name);
1054
1055         if (!link)
1056                 link = ERR_PTR(-ENOMEM);
1057         else {
1058                 len = v9fs_readlink(dentry, link, PATH_MAX);
1059
1060                 if (len < 0) {
1061                         __putname(link);
1062                         link = ERR_PTR(len);
1063                 } else
1064                         link[min(len, PATH_MAX-1)] = 0;
1065         }
1066         nd_set_link(nd, link);
1067
1068         return NULL;
1069 }
1070
1071 /**
1072  * v9fs_vfs_put_link - release a symlink path
1073  * @dentry: dentry for symlink
1074  * @nd: nameidata
1075  * @p: unused
1076  *
1077  */
1078
1079 static void
1080 v9fs_vfs_put_link(struct dentry *dentry, struct nameidata *nd, void *p)
1081 {
1082         char *s = nd_get_link(nd);
1083
1084         P9_DPRINTK(P9_DEBUG_VFS, " %s %s\n", dentry->d_name.name,
1085                 IS_ERR(s) ? "<error>" : s);
1086         if (!IS_ERR(s))
1087                 __putname(s);
1088 }
1089
1090 /**
1091  * v9fs_vfs_mkspecial - create a special file
1092  * @dir: inode to create special file in
1093  * @dentry: dentry to create
1094  * @mode: mode to create special file
1095  * @extension: 9p2000.u format extension string representing special file
1096  *
1097  */
1098
1099 static int v9fs_vfs_mkspecial(struct inode *dir, struct dentry *dentry,
1100         int mode, const char *extension)
1101 {
1102         u32 perm;
1103         struct v9fs_session_info *v9ses;
1104         struct p9_fid *fid;
1105
1106         v9ses = v9fs_inode2v9ses(dir);
1107         if (!v9fs_extended(v9ses)) {
1108                 P9_DPRINTK(P9_DEBUG_ERROR, "not extended\n");
1109                 return -EPERM;
1110         }
1111
1112         perm = unixmode2p9mode(v9ses, mode);
1113         fid = v9fs_create(v9ses, dir, dentry, (char *) extension, perm,
1114                                                                 P9_OREAD);
1115         if (IS_ERR(fid))
1116                 return PTR_ERR(fid);
1117
1118         p9_client_clunk(fid);
1119         return 0;
1120 }
1121
1122 /**
1123  * v9fs_vfs_symlink - helper function to create symlinks
1124  * @dir: directory inode containing symlink
1125  * @dentry: dentry for symlink
1126  * @symname: symlink data
1127  *
1128  * See Also: 9P2000.u RFC for more information
1129  *
1130  */
1131
1132 static int
1133 v9fs_vfs_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
1134 {
1135         P9_DPRINTK(P9_DEBUG_VFS, " %lu,%s,%s\n", dir->i_ino,
1136                                         dentry->d_name.name, symname);
1137
1138         return v9fs_vfs_mkspecial(dir, dentry, S_IFLNK, symname);
1139 }
1140
1141 /**
1142  * v9fs_vfs_link - create a hardlink
1143  * @old_dentry: dentry for file to link to
1144  * @dir: inode destination for new link
1145  * @dentry: dentry for link
1146  *
1147  */
1148
1149 static int
1150 v9fs_vfs_link(struct dentry *old_dentry, struct inode *dir,
1151               struct dentry *dentry)
1152 {
1153         int retval;
1154         struct p9_fid *oldfid;
1155         char *name;
1156
1157         P9_DPRINTK(P9_DEBUG_VFS,
1158                 " %lu,%s,%s\n", dir->i_ino, dentry->d_name.name,
1159                 old_dentry->d_name.name);
1160
1161         oldfid = v9fs_fid_clone(old_dentry);
1162         if (IS_ERR(oldfid))
1163                 return PTR_ERR(oldfid);
1164
1165         name = __getname();
1166         if (unlikely(!name)) {
1167                 retval = -ENOMEM;
1168                 goto clunk_fid;
1169         }
1170
1171         sprintf(name, "%d\n", oldfid->fid);
1172         retval = v9fs_vfs_mkspecial(dir, dentry, P9_DMLINK, name);
1173         __putname(name);
1174
1175 clunk_fid:
1176         p9_client_clunk(oldfid);
1177         return retval;
1178 }
1179
1180 /**
1181  * v9fs_vfs_mknod - create a special file
1182  * @dir: inode destination for new link
1183  * @dentry: dentry for file
1184  * @mode: mode for creation
1185  * @rdev: device associated with special file
1186  *
1187  */
1188
1189 static int
1190 v9fs_vfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t rdev)
1191 {
1192         int retval;
1193         char *name;
1194
1195         P9_DPRINTK(P9_DEBUG_VFS,
1196                 " %lu,%s mode: %x MAJOR: %u MINOR: %u\n", dir->i_ino,
1197                 dentry->d_name.name, mode, MAJOR(rdev), MINOR(rdev));
1198
1199         if (!new_valid_dev(rdev))
1200                 return -EINVAL;
1201
1202         name = __getname();
1203         if (!name)
1204                 return -ENOMEM;
1205         /* build extension */
1206         if (S_ISBLK(mode))
1207                 sprintf(name, "b %u %u", MAJOR(rdev), MINOR(rdev));
1208         else if (S_ISCHR(mode))
1209                 sprintf(name, "c %u %u", MAJOR(rdev), MINOR(rdev));
1210         else if (S_ISFIFO(mode))
1211                 *name = 0;
1212         else {
1213                 __putname(name);
1214                 return -EINVAL;
1215         }
1216
1217         retval = v9fs_vfs_mkspecial(dir, dentry, mode, name);
1218         __putname(name);
1219
1220         return retval;
1221 }
1222
1223 static const struct inode_operations v9fs_dir_inode_operations_ext = {
1224         .create = v9fs_vfs_create,
1225         .lookup = v9fs_vfs_lookup,
1226         .symlink = v9fs_vfs_symlink,
1227         .link = v9fs_vfs_link,
1228         .unlink = v9fs_vfs_unlink,
1229         .mkdir = v9fs_vfs_mkdir,
1230         .rmdir = v9fs_vfs_rmdir,
1231         .mknod = v9fs_vfs_mknod,
1232         .rename = v9fs_vfs_rename,
1233         .readlink = v9fs_vfs_readlink,
1234         .getattr = v9fs_vfs_getattr,
1235         .setattr = v9fs_vfs_setattr,
1236 };
1237
1238 static const struct inode_operations v9fs_dir_inode_operations = {
1239         .create = v9fs_vfs_create,
1240         .lookup = v9fs_vfs_lookup,
1241         .unlink = v9fs_vfs_unlink,
1242         .mkdir = v9fs_vfs_mkdir,
1243         .rmdir = v9fs_vfs_rmdir,
1244         .mknod = v9fs_vfs_mknod,
1245         .rename = v9fs_vfs_rename,
1246         .getattr = v9fs_vfs_getattr,
1247         .setattr = v9fs_vfs_setattr,
1248 };
1249
1250 static const struct inode_operations v9fs_file_inode_operations = {
1251         .getattr = v9fs_vfs_getattr,
1252         .setattr = v9fs_vfs_setattr,
1253 };
1254
1255 static const struct inode_operations v9fs_symlink_inode_operations = {
1256         .readlink = v9fs_vfs_readlink,
1257         .follow_link = v9fs_vfs_follow_link,
1258         .put_link = v9fs_vfs_put_link,
1259         .getattr = v9fs_vfs_getattr,
1260         .setattr = v9fs_vfs_setattr,
1261 };