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 int v9fs_init_inode(struct v9fs_session_info *v9ses,
 247                     struct inode *inode, int mode)
 248 {
 249         int err = 0;
 250
 251         inode_init_owner(inode, NULL, mode);
 252         inode->i_blocks = 0;
 253         inode->i_rdev = 0;
 254         inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 255         inode->i_mapping->a_ops = &v9fs_addr_operations;
 256
 257         switch (mode & S_IFMT) {
 258         case S_IFIFO:
 259         case S_IFBLK:
 260         case S_IFCHR:
 261         case S_IFSOCK:
 262                 if (v9fs_proto_dotl(v9ses)) {
 263                         inode->i_op = &v9fs_file_inode_operations_dotl;
 264                         inode->i_fop = &v9fs_file_operations_dotl;
 265                 } else if (v9fs_proto_dotu(v9ses)) {
 266                         inode->i_op = &v9fs_file_inode_operations;
 267                         inode->i_fop = &v9fs_file_operations;
 268                 } else {
 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                 if (v9fs_proto_dotl(v9ses)) {
 278                         inode->i_op = &v9fs_file_inode_operations_dotl;
 279                         if (v9ses->cache)
 280                                 inode->i_fop =
 281                                         &v9fs_cached_file_operations_dotl;
 282                         else
 283                                 inode->i_fop = &v9fs_file_operations_dotl;
 284                 } else {
 285                         inode->i_op = &v9fs_file_inode_operations;
 286                         if (v9ses->cache)
 287                                 inode->i_fop = &v9fs_cached_file_operations;
 288                         else
 289                                 inode->i_fop = &v9fs_file_operations;
 290                 }
 291
 292                 break;
 293         case S_IFLNK:
 294                 if (!v9fs_proto_dotu(v9ses) && !v9fs_proto_dotl(v9ses)) {
 295                         P9_DPRINTK(P9_DEBUG_ERROR, "extended modes used with "
 296                                                 "legacy protocol.\n");
 297                         err = -EINVAL;
 298                         goto error;
 299                 }
 300
 301                 if (v9fs_proto_dotl(v9ses))
 302                         inode->i_op = &v9fs_symlink_inode_operations_dotl;
 303                 else
 304                         inode->i_op = &v9fs_symlink_inode_operations;
 305
 306                 break;
 307         case S_IFDIR:
 308                 inc_nlink(inode);
 309                 if (v9fs_proto_dotl(v9ses))
 310                         inode->i_op = &v9fs_dir_inode_operations_dotl;
 311                 else if (v9fs_proto_dotu(v9ses))
 312                         inode->i_op = &v9fs_dir_inode_operations_dotu;
 313                 else
 314                         inode->i_op = &v9fs_dir_inode_operations;
 315
 316                 if (v9fs_proto_dotl(v9ses))
 317                         inode->i_fop = &v9fs_dir_operations_dotl;
 318                 else
 319                         inode->i_fop = &v9fs_dir_operations;
 320
 321                 break;
 322         default:
 323                 P9_DPRINTK(P9_DEBUG_ERROR, "BAD mode 0x%x S_IFMT 0x%x\n",
 324                            mode, mode & S_IFMT);
 325                 err = -EINVAL;
 326                 goto error;
 327         }
 328 error:
 329         return err;
 330
 331 }
 332
 333 /**
 334  * v9fs_get_inode - helper function to setup an inode
 335  * @sb: superblock
 336  * @mode: mode to setup inode with
 337  *
 338  */
 339
 340 struct inode *v9fs_get_inode(struct super_block *sb, int mode)
 341 {
 342         int err;
 343         struct inode *inode;
 344         struct v9fs_session_info *v9ses = sb->s_fs_info;
 345
 346         P9_DPRINTK(P9_DEBUG_VFS, "super block: %p mode: %o\n", sb, mode);
 347
 348         inode = new_inode(sb);
 349         if (!inode) {
 350                 P9_EPRINTK(KERN_WARNING, "Problem allocating inode\n");
 351                 return ERR_PTR(-ENOMEM);
 352         }
 353         err = v9fs_init_inode(v9ses, inode, mode);
 354         if (err) {
 355                 iput(inode);
 356                 return ERR_PTR(err);
 357         }
 358         return inode;
 359 }
 360
 361 /*
 362 static struct v9fs_fid*
 363 v9fs_clone_walk(struct v9fs_session_info *v9ses, u32 fid, struct dentry *dentry)
 364 {
 365         int err;
 366         int nfid;
 367         struct v9fs_fid *ret;
 368         struct v9fs_fcall *fcall;
 369
 370         nfid = v9fs_get_idpool(&v9ses->fidpool);
 371         if (nfid < 0) {
 372                 eprintk(KERN_WARNING, "no free fids available\n");
 373                 return ERR_PTR(-ENOSPC);
 374         }
 375
 376         err = v9fs_t_walk(v9ses, fid, nfid, (char *) dentry->d_name.name,
 377                 &fcall);
 378
 379         if (err < 0) {
 380                 if (fcall && fcall->id == RWALK)
 381                         goto clunk_fid;
 382
 383                 PRINT_FCALL_ERROR("walk error", fcall);
 384                 v9fs_put_idpool(nfid, &v9ses->fidpool);
 385                 goto error;
 386         }
 387
 388         kfree(fcall);
 389         fcall = NULL;
 390         ret = v9fs_fid_create(v9ses, nfid);
 391         if (!ret) {
 392                 err = -ENOMEM;
 393                 goto clunk_fid;
 394         }
 395
 396         err = v9fs_fid_insert(ret, dentry);
 397         if (err < 0) {
 398                 v9fs_fid_destroy(ret);
 399                 goto clunk_fid;
 400         }
 401
 402         return ret;
 403
 404 clunk_fid:
 405         v9fs_t_clunk(v9ses, nfid);
 406
 407 error:
 408         kfree(fcall);
 409         return ERR_PTR(err);
 410 }
 411 */
 412
 413
 414 /**
 415  * v9fs_clear_inode - release an inode
 416  * @inode: inode to release
 417  *
 418  */
 419 void v9fs_evict_inode(struct inode *inode)
 420 {
 421         truncate_inode_pages(inode->i_mapping, 0);
 422         end_writeback(inode);
 423         filemap_fdatawrite(inode->i_mapping);
 424
 425 #ifdef CONFIG_9P_FSCACHE
 426         v9fs_cache_inode_put_cookie(inode);
 427 #endif
 428         /* clunk the fid stashed in inode->i_private */
 429         if (inode->i_private) {
 430                 p9_client_clunk((struct p9_fid *)inode->i_private);
 431                 inode->i_private = NULL;
 432         }
 433 }
 434
 435 static struct inode *v9fs_qid_iget(struct super_block *sb,
 436                                    struct p9_qid *qid,
 437                                    struct p9_wstat *st)
 438 {
 439         int retval, umode;
 440         unsigned long i_ino;
 441         struct inode *inode;
 442         struct v9fs_session_info *v9ses = sb->s_fs_info;
 443
 444         i_ino = v9fs_qid2ino(qid);
 445         inode = iget_locked(sb, i_ino);
 446         if (!inode)
 447                 return ERR_PTR(-ENOMEM);
 448         if (!(inode->i_state & I_NEW))
 449                 return inode;
 450         /*
 451          * initialize the inode with the stat info
 452          * FIXME!! we may need support for stale inodes
 453          * later.
 454          */
 455         umode = p9mode2unixmode(v9ses, st->mode);
 456         retval = v9fs_init_inode(v9ses, inode, umode);
 457         if (retval)
 458                 goto error;
 459
 460         v9fs_stat2inode(st, inode, sb);
 461 #ifdef CONFIG_9P_FSCACHE
 462         v9fs_vcookie_set_qid(ret, &st->qid);
 463         v9fs_cache_inode_get_cookie(inode);
 464 #endif
 465         unlock_new_inode(inode);
 466         return inode;
 467 error:
 468         unlock_new_inode(inode);
 469         iput(inode);
 470         return ERR_PTR(retval);
 471
 472 }
 473
 474 struct inode *
 475 v9fs_inode(struct v9fs_session_info *v9ses, struct p9_fid *fid,
 476            struct super_block *sb)
 477 {
 478         struct p9_wstat *st;
 479         struct inode *inode = NULL;
 480
 481         st = p9_client_stat(fid);
 482         if (IS_ERR(st))
 483                 return ERR_CAST(st);
 484
 485         inode = v9fs_qid_iget(sb, &st->qid, st);
 486         p9stat_free(st);
 487         kfree(st);
 488         return inode;
 489 }
 490
 491 /**
 492  * v9fs_remove - helper function to remove files and directories
 493  * @dir: directory inode that is being deleted
 494  * @file:  dentry that is being deleted
 495  * @rmdir: removing a directory
 496  *
 497  */
 498
 499 static int v9fs_remove(struct inode *dir, struct dentry *file, int rmdir)
 500 {
 501         int retval;
 502         struct inode *file_inode;
 503         struct p9_fid *v9fid;
 504
 505         P9_DPRINTK(P9_DEBUG_VFS, "inode: %p dentry: %p rmdir: %d\n", dir, file,
 506                 rmdir);
 507
 508         file_inode = file->d_inode;
 509         v9fid = v9fs_fid_clone(file);
 510         if (IS_ERR(v9fid))
 511                 return PTR_ERR(v9fid);
 512
 513         retval = p9_client_remove(v9fid);
 514         if (!retval)
 515                 drop_nlink(file_inode);
 516         return retval;
 517 }
 518
 519 /**
 520  * v9fs_create - Create a file
 521  * @v9ses: session information
 522  * @dir: directory that dentry is being created in
 523  * @dentry:  dentry that is being created
 524  * @extension: 9p2000.u extension string to support devices, etc.
 525  * @perm: create permissions
 526  * @mode: open mode
 527  *
 528  */
 529 static struct p9_fid *
 530 v9fs_create(struct v9fs_session_info *v9ses, struct inode *dir,
 531                 struct dentry *dentry, char *extension, u32 perm, u8 mode)
 532 {
 533         int err;
 534         char *name;
 535         struct p9_fid *dfid, *ofid, *fid;
 536         struct inode *inode;
 537
 538         P9_DPRINTK(P9_DEBUG_VFS, "name %s\n", dentry->d_name.name);
 539
 540         err = 0;
 541         ofid = NULL;
 542         fid = NULL;
 543         name = (char *) dentry->d_name.name;
 544         dfid = v9fs_fid_lookup(dentry->d_parent);
 545         if (IS_ERR(dfid)) {
 546                 err = PTR_ERR(dfid);
 547                 P9_DPRINTK(P9_DEBUG_VFS, "fid lookup failed %d\n", err);
 548                 return ERR_PTR(err);
 549         }
 550
 551         /* clone a fid to use for creation */
 552         ofid = p9_client_walk(dfid, 0, NULL, 1);
 553         if (IS_ERR(ofid)) {
 554                 err = PTR_ERR(ofid);
 555                 P9_DPRINTK(P9_DEBUG_VFS, "p9_client_walk failed %d\n", err);
 556                 return ERR_PTR(err);
 557         }
 558
 559         err = p9_client_fcreate(ofid, name, perm, mode, extension);
 560         if (err < 0) {
 561                 P9_DPRINTK(P9_DEBUG_VFS, "p9_client_fcreate failed %d\n", err);
 562                 goto error;
 563         }
 564
 565         /* now walk from the parent so we can get unopened fid */
 566         fid = p9_client_walk(dfid, 1, &name, 1);
 567         if (IS_ERR(fid)) {
 568                 err = PTR_ERR(fid);
 569                 P9_DPRINTK(P9_DEBUG_VFS, "p9_client_walk failed %d\n", err);
 570                 fid = NULL;
 571                 goto error;
 572         }
 573
 574         /* instantiate inode and assign the unopened fid to the dentry */
 575         inode = v9fs_inode_from_fid(v9ses, fid, dir->i_sb);
 576         if (IS_ERR(inode)) {
 577                 err = PTR_ERR(inode);
 578                 P9_DPRINTK(P9_DEBUG_VFS, "inode creation failed %d\n", err);
 579                 goto error;
 580         }
 581         d_instantiate(dentry, inode);
 582         err = v9fs_fid_add(dentry, fid);
 583         if (err < 0)
 584                 goto error;
 585
 586         return ofid;
 587
 588 error:
 589         if (ofid)
 590                 p9_client_clunk(ofid);
 591
 592         if (fid)
 593                 p9_client_clunk(fid);
 594
 595         return ERR_PTR(err);
 596 }
 597
 598 /**
 599  * v9fs_vfs_create - VFS hook to create files
 600  * @dir: directory inode that is being created
 601  * @dentry:  dentry that is being deleted
 602  * @mode: create permissions
 603  * @nd: path information
 604  *
 605  */
 606
 607 static int
 608 v9fs_vfs_create(struct inode *dir, struct dentry *dentry, int mode,
 609                 struct nameidata *nd)
 610 {
 611         int err;
 612         u32 perm;
 613         int flags;
 614         struct v9fs_session_info *v9ses;
 615         struct p9_fid *fid, *inode_fid;
 616         struct file *filp;
 617
 618         err = 0;
 619         fid = NULL;
 620         v9ses = v9fs_inode2v9ses(dir);
 621         perm = unixmode2p9mode(v9ses, mode);
 622         if (nd && nd->flags & LOOKUP_OPEN)
 623                 flags = nd->intent.open.flags - 1;
 624         else
 625                 flags = O_RDWR;
 626
 627         fid = v9fs_create(v9ses, dir, dentry, NULL, perm,
 628                                 v9fs_uflags2omode(flags,
 629                                                 v9fs_proto_dotu(v9ses)));
 630         if (IS_ERR(fid)) {
 631                 err = PTR_ERR(fid);
 632                 fid = NULL;
 633                 goto error;
 634         }
 635
 636         /* if we are opening a file, assign the open fid to the file */
 637         if (nd && nd->flags & LOOKUP_OPEN) {
 638                 if (v9ses->cache && !dentry->d_inode->i_private) {
 639                         /*
 640                          * clone a fid and add it to inode->i_private
 641                          * we do it during open time instead of
 642                          * page dirty time via write_begin/page_mkwrite
 643                          * because we want write after unlink usecase
 644                          * to work.
 645                          */
 646                         inode_fid = v9fs_writeback_fid(dentry);
 647                         if (IS_ERR(inode_fid)) {
 648                                 err = PTR_ERR(inode_fid);
 649                                 goto error;
 650                         }
 651                         dentry->d_inode->i_private = (void *) inode_fid;
 652                 }
 653                 filp = lookup_instantiate_filp(nd, dentry, generic_file_open);
 654                 if (IS_ERR(filp)) {
 655                         err = PTR_ERR(filp);
 656                         goto error;
 657                 }
 658
 659                 filp->private_data = fid;
 660 #ifdef CONFIG_9P_FSCACHE
 661                 if (v9ses->cache)
 662                         v9fs_cache_inode_set_cookie(dentry->d_inode, filp);
 663 #endif
 664         } else
 665                 p9_client_clunk(fid);
 666
 667         return 0;
 668
 669 error:
 670         if (fid)
 671                 p9_client_clunk(fid);
 672
 673         return err;
 674 }
 675
 676 /**
 677  * v9fs_vfs_mkdir - VFS mkdir hook to create a directory
 678  * @dir:  inode that is being unlinked
 679  * @dentry: dentry that is being unlinked
 680  * @mode: mode for new directory
 681  *
 682  */
 683
 684 static int v9fs_vfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 685 {
 686         int err;
 687         u32 perm;
 688         struct v9fs_session_info *v9ses;
 689         struct p9_fid *fid;
 690
 691         P9_DPRINTK(P9_DEBUG_VFS, "name %s\n", dentry->d_name.name);
 692         err = 0;
 693         v9ses = v9fs_inode2v9ses(dir);
 694         perm = unixmode2p9mode(v9ses, mode | S_IFDIR);
 695         fid = v9fs_create(v9ses, dir, dentry, NULL, perm, P9_OREAD);
 696         if (IS_ERR(fid)) {
 697                 err = PTR_ERR(fid);
 698                 fid = NULL;
 699         }
 700
 701         if (fid)
 702                 p9_client_clunk(fid);
 703
 704         return err;
 705 }
 706
 707 /**
 708  * v9fs_vfs_lookup - VFS lookup hook to "walk" to a new inode
 709  * @dir:  inode that is being walked from
 710  * @dentry: dentry that is being walked to?
 711  * @nameidata: path data
 712  *
 713  */
 714
 715 struct dentry *v9fs_vfs_lookup(struct inode *dir, struct dentry *dentry,
 716                                       struct nameidata *nameidata)
 717 {
 718         struct super_block *sb;
 719         struct v9fs_session_info *v9ses;
 720         struct p9_fid *dfid, *fid;
 721         struct inode *inode;
 722         char *name;
 723         int result = 0;
 724
 725         P9_DPRINTK(P9_DEBUG_VFS, "dir: %p dentry: (%s) %p nameidata: %p\n",
 726                 dir, dentry->d_name.name, dentry, nameidata);
 727
 728         if (dentry->d_name.len > NAME_MAX)
 729                 return ERR_PTR(-ENAMETOOLONG);
 730
 731         sb = dir->i_sb;
 732         v9ses = v9fs_inode2v9ses(dir);
 733         /* We can walk d_parent because we hold the dir->i_mutex */
 734         dfid = v9fs_fid_lookup(dentry->d_parent);
 735         if (IS_ERR(dfid))
 736                 return ERR_CAST(dfid);
 737
 738         name = (char *) dentry->d_name.name;
 739         fid = p9_client_walk(dfid, 1, &name, 1);
 740         if (IS_ERR(fid)) {
 741                 result = PTR_ERR(fid);
 742                 if (result == -ENOENT) {
 743                         inode = NULL;
 744                         goto inst_out;
 745                 }
 746
 747                 return ERR_PTR(result);
 748         }
 749
 750         inode = v9fs_inode_from_fid(v9ses, fid, dir->i_sb);
 751         if (IS_ERR(inode)) {
 752                 result = PTR_ERR(inode);
 753                 inode = NULL;
 754                 goto error;
 755         }
 756
 757         result = v9fs_fid_add(dentry, fid);
 758         if (result < 0)
 759                 goto error_iput;
 760
 761 inst_out:
 762         d_add(dentry, inode);
 763         return NULL;
 764
 765 error_iput:
 766         iput(inode);
 767 error:
 768         p9_client_clunk(fid);
 769
 770         return ERR_PTR(result);
 771 }
 772
 773 /**
 774  * v9fs_vfs_unlink - VFS unlink hook to delete an inode
 775  * @i:  inode that is being unlinked
 776  * @d: dentry that is being unlinked
 777  *
 778  */
 779
 780 int v9fs_vfs_unlink(struct inode *i, struct dentry *d)
 781 {
 782         return v9fs_remove(i, d, 0);
 783 }
 784
 785 /**
 786  * v9fs_vfs_rmdir - VFS unlink hook to delete a directory
 787  * @i:  inode that is being unlinked
 788  * @d: dentry that is being unlinked
 789  *
 790  */
 791
 792 int v9fs_vfs_rmdir(struct inode *i, struct dentry *d)
 793 {
 794         return v9fs_remove(i, d, 1);
 795 }
 796
 797 /**
 798  * v9fs_vfs_rename - VFS hook to rename an inode
 799  * @old_dir:  old dir inode
 800  * @old_dentry: old dentry
 801  * @new_dir: new dir inode
 802  * @new_dentry: new dentry
 803  *
 804  */
 805
 806 int
 807 v9fs_vfs_rename(struct inode *old_dir, struct dentry *old_dentry,
 808                 struct inode *new_dir, struct dentry *new_dentry)
 809 {
 810         struct inode *old_inode;
 811         struct v9fs_session_info *v9ses;
 812         struct p9_fid *oldfid;
 813         struct p9_fid *olddirfid;
 814         struct p9_fid *newdirfid;
 815         struct p9_wstat wstat;
 816         int retval;
 817
 818         P9_DPRINTK(P9_DEBUG_VFS, "\n");
 819         retval = 0;
 820         old_inode = old_dentry->d_inode;
 821         v9ses = v9fs_inode2v9ses(old_inode);
 822         oldfid = v9fs_fid_lookup(old_dentry);
 823         if (IS_ERR(oldfid))
 824                 return PTR_ERR(oldfid);
 825
 826         olddirfid = v9fs_fid_clone(old_dentry->d_parent);
 827         if (IS_ERR(olddirfid)) {
 828                 retval = PTR_ERR(olddirfid);
 829                 goto done;
 830         }
 831
 832         newdirfid = v9fs_fid_clone(new_dentry->d_parent);
 833         if (IS_ERR(newdirfid)) {
 834                 retval = PTR_ERR(newdirfid);
 835                 goto clunk_olddir;
 836         }
 837
 838         down_write(&v9ses->rename_sem);
 839         if (v9fs_proto_dotl(v9ses)) {
 840                 retval = p9_client_rename(oldfid, newdirfid,
 841                                         (char *) new_dentry->d_name.name);
 842                 if (retval != -ENOSYS)
 843                         goto clunk_newdir;
 844         }
 845         if (old_dentry->d_parent != new_dentry->d_parent) {
 846                 /*
 847                  * 9P .u can only handle file rename in the same directory
 848                  */
 849
 850                 P9_DPRINTK(P9_DEBUG_ERROR,
 851                                 "old dir and new dir are different\n");
 852                 retval = -EXDEV;
 853                 goto clunk_newdir;
 854         }
 855         v9fs_blank_wstat(&wstat);
 856         wstat.muid = v9ses->uname;
 857         wstat.name = (char *) new_dentry->d_name.name;
 858         retval = p9_client_wstat(oldfid, &wstat);
 859
 860 clunk_newdir:
 861         if (!retval)
 862                 /* successful rename */
 863                 d_move(old_dentry, new_dentry);
 864         up_write(&v9ses->rename_sem);
 865         p9_client_clunk(newdirfid);
 866
 867 clunk_olddir:
 868         p9_client_clunk(olddirfid);
 869
 870 done:
 871         return retval;
 872 }
 873
 874 /**
 875  * v9fs_vfs_getattr - retrieve file metadata
 876  * @mnt: mount information
 877  * @dentry: file to get attributes on
 878  * @stat: metadata structure to populate
 879  *
 880  */
 881
 882 static int
 883 v9fs_vfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
 884                  struct kstat *stat)
 885 {
 886         int err;
 887         struct v9fs_session_info *v9ses;
 888         struct p9_fid *fid;
 889         struct p9_wstat *st;
 890
 891         P9_DPRINTK(P9_DEBUG_VFS, "dentry: %p\n", dentry);
 892         err = -EPERM;
 893         v9ses = v9fs_inode2v9ses(dentry->d_inode);
 894         if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE) {
 895                 generic_fillattr(dentry->d_inode, stat);
 896                 return 0;
 897         }
 898         fid = v9fs_fid_lookup(dentry);
 899         if (IS_ERR(fid))
 900                 return PTR_ERR(fid);
 901
 902         st = p9_client_stat(fid);
 903         if (IS_ERR(st))
 904                 return PTR_ERR(st);
 905
 906         v9fs_stat2inode(st, dentry->d_inode, dentry->d_inode->i_sb);
 907                 generic_fillattr(dentry->d_inode, stat);
 908
 909         p9stat_free(st);
 910         kfree(st);
 911         return 0;
 912 }
 913
 914 /**
 915  * v9fs_vfs_setattr - set file metadata
 916  * @dentry: file whose metadata to set
 917  * @iattr: metadata assignment structure
 918  *
 919  */
 920
 921 static int v9fs_vfs_setattr(struct dentry *dentry, struct iattr *iattr)
 922 {
 923         int retval;
 924         struct v9fs_session_info *v9ses;
 925         struct p9_fid *fid;
 926         struct p9_wstat wstat;
 927
 928         P9_DPRINTK(P9_DEBUG_VFS, "\n");
 929         retval = -EPERM;
 930         v9ses = v9fs_inode2v9ses(dentry->d_inode);
 931         fid = v9fs_fid_lookup(dentry);
 932         if(IS_ERR(fid))
 933                 return PTR_ERR(fid);
 934
 935         v9fs_blank_wstat(&wstat);
 936         if (iattr->ia_valid & ATTR_MODE)
 937                 wstat.mode = unixmode2p9mode(v9ses, iattr->ia_mode);
 938
 939         if (iattr->ia_valid & ATTR_MTIME)
 940                 wstat.mtime = iattr->ia_mtime.tv_sec;
 941
 942         if (iattr->ia_valid & ATTR_ATIME)
 943                 wstat.atime = iattr->ia_atime.tv_sec;
 944
 945         if (iattr->ia_valid & ATTR_SIZE)
 946                 wstat.length = iattr->ia_size;
 947
 948         if (v9fs_proto_dotu(v9ses)) {
 949                 if (iattr->ia_valid & ATTR_UID)
 950                         wstat.n_uid = iattr->ia_uid;
 951
 952                 if (iattr->ia_valid & ATTR_GID)
 953                         wstat.n_gid = iattr->ia_gid;
 954         }
 955
 956         retval = p9_client_wstat(fid, &wstat);
 957         if (retval < 0)
 958                 return retval;
 959
 960         if ((iattr->ia_valid & ATTR_SIZE) &&
 961             iattr->ia_size != i_size_read(dentry->d_inode)) {
 962                 retval = vmtruncate(dentry->d_inode, iattr->ia_size);
 963                 if (retval)
 964                         return retval;
 965         }
 966
 967         setattr_copy(dentry->d_inode, iattr);
 968         mark_inode_dirty(dentry->d_inode);
 969         return 0;
 970 }
 971
 972 /**
 973  * v9fs_stat2inode - populate an inode structure with mistat info
 974  * @stat: Plan 9 metadata (mistat) structure
 975  * @inode: inode to populate
 976  * @sb: superblock of filesystem
 977  *
 978  */
 979
 980 void
 981 v9fs_stat2inode(struct p9_wstat *stat, struct inode *inode,
 982         struct super_block *sb)
 983 {
 984         char ext[32];
 985         char tag_name[14];
 986         unsigned int i_nlink;
 987         struct v9fs_session_info *v9ses = sb->s_fs_info;
 988
 989         inode->i_nlink = 1;
 990
 991         inode->i_atime.tv_sec = stat->atime;
 992         inode->i_mtime.tv_sec = stat->mtime;
 993         inode->i_ctime.tv_sec = stat->mtime;
 994
 995         inode->i_uid = v9ses->dfltuid;
 996         inode->i_gid = v9ses->dfltgid;
 997
 998         if (v9fs_proto_dotu(v9ses)) {
 999                 inode->i_uid = stat->n_uid;
1000                 inode->i_gid = stat->n_gid;
1001         }
1002         if ((S_ISREG(inode->i_mode)) || (S_ISDIR(inode->i_mode))) {
1003                 if (v9fs_proto_dotu(v9ses) && (stat->extension[0] != '\0')) {
1004                         /*
1005                          * Hadlink support got added later to
1006                          * to the .u extension. So there can be
1007                          * server out there that doesn't support
1008                          * this even with .u extension. So check
1009                          * for non NULL stat->extension
1010                          */
1011                         strncpy(ext, stat->extension, sizeof(ext));
1012                         /* HARDLINKCOUNT %u */
1013                         sscanf(ext, "%13s %u", tag_name, &i_nlink);
1014                         if (!strncmp(tag_name, "HARDLINKCOUNT", 13))
1015                                 inode->i_nlink = i_nlink;
1016                 }
1017         }
1018         inode->i_mode = p9mode2unixmode(v9ses, stat->mode);
1019         if ((S_ISBLK(inode->i_mode)) || (S_ISCHR(inode->i_mode))) {
1020                 char type = 0;
1021                 int major = -1;
1022                 int minor = -1;
1023
1024                 strncpy(ext, stat->extension, sizeof(ext));
1025                 sscanf(ext, "%c %u %u", &type, &major, &minor);
1026                 switch (type) {
1027                 case 'c':
1028                         inode->i_mode &= ~S_IFBLK;
1029                         inode->i_mode |= S_IFCHR;
1030                         break;
1031                 case 'b':
1032                         break;
1033                 default:
1034                         P9_DPRINTK(P9_DEBUG_ERROR,
1035                                 "Unknown special type %c %s\n", type,
1036                                 stat->extension);
1037                 };
1038                 inode->i_rdev = MKDEV(major, minor);
1039                 init_special_inode(inode, inode->i_mode, inode->i_rdev);
1040         } else
1041                 inode->i_rdev = 0;
1042
1043         i_size_write(inode, stat->length);
1044
1045         /* not real number of blocks, but 512 byte ones ... */
1046         inode->i_blocks = (i_size_read(inode) + 512 - 1) >> 9;
1047 }
1048
1049 /**
1050  * v9fs_qid2ino - convert qid into inode number
1051  * @qid: qid to hash
1052  *
1053  * BUG: potential for inode number collisions?
1054  */
1055
1056 ino_t v9fs_qid2ino(struct p9_qid *qid)
1057 {
1058         u64 path = qid->path + 2;
1059         ino_t i = 0;
1060
1061         if (sizeof(ino_t) == sizeof(path))
1062                 memcpy(&i, &path, sizeof(ino_t));
1063         else
1064                 i = (ino_t) (path ^ (path >> 32));
1065
1066         return i;
1067 }
1068
1069 /**
1070  * v9fs_readlink - read a symlink's location (internal version)
1071  * @dentry: dentry for symlink
1072  * @buffer: buffer to load symlink location into
1073  * @buflen: length of buffer
1074  *
1075  */
1076
1077 static int v9fs_readlink(struct dentry *dentry, char *buffer, int buflen)
1078 {
1079         int retval;
1080
1081         struct v9fs_session_info *v9ses;
1082         struct p9_fid *fid;
1083         struct p9_wstat *st;
1084
1085         P9_DPRINTK(P9_DEBUG_VFS, " %s\n", dentry->d_name.name);
1086         retval = -EPERM;
1087         v9ses = v9fs_inode2v9ses(dentry->d_inode);
1088         fid = v9fs_fid_lookup(dentry);
1089         if (IS_ERR(fid))
1090                 return PTR_ERR(fid);
1091
1092         if (!v9fs_proto_dotu(v9ses))
1093                 return -EBADF;
1094
1095         st = p9_client_stat(fid);
1096         if (IS_ERR(st))
1097                 return PTR_ERR(st);
1098
1099         if (!(st->mode & P9_DMSYMLINK)) {
1100                 retval = -EINVAL;
1101                 goto done;
1102         }
1103
1104         /* copy extension buffer into buffer */
1105         strncpy(buffer, st->extension, buflen);
1106
1107         P9_DPRINTK(P9_DEBUG_VFS,
1108                 "%s -> %s (%s)\n", dentry->d_name.name, st->extension, buffer);
1109
1110         retval = strnlen(buffer, buflen);
1111 done:
1112         p9stat_free(st);
1113         kfree(st);
1114         return retval;
1115 }
1116
1117 /**
1118  * v9fs_vfs_follow_link - follow a symlink path
1119  * @dentry: dentry for symlink
1120  * @nd: nameidata
1121  *
1122  */
1123
1124 static void *v9fs_vfs_follow_link(struct dentry *dentry, struct nameidata *nd)
1125 {
1126         int len = 0;
1127         char *link = __getname();
1128
1129         P9_DPRINTK(P9_DEBUG_VFS, "%s n", dentry->d_name.name);
1130
1131         if (!link)
1132                 link = ERR_PTR(-ENOMEM);
1133         else {
1134                 len = v9fs_readlink(dentry, link, PATH_MAX);
1135
1136                 if (len < 0) {
1137                         __putname(link);
1138                         link = ERR_PTR(len);
1139                 } else
1140                         link[min(len, PATH_MAX-1)] = 0;
1141         }
1142         nd_set_link(nd, link);
1143
1144         return NULL;
1145 }
1146
1147 /**
1148  * v9fs_vfs_put_link - release a symlink path
1149  * @dentry: dentry for symlink
1150  * @nd: nameidata
1151  * @p: unused
1152  *
1153  */
1154
1155 void
1156 v9fs_vfs_put_link(struct dentry *dentry, struct nameidata *nd, void *p)
1157 {
1158         char *s = nd_get_link(nd);
1159
1160         P9_DPRINTK(P9_DEBUG_VFS, " %s %s\n", dentry->d_name.name,
1161                 IS_ERR(s) ? "<error>" : s);
1162         if (!IS_ERR(s))
1163                 __putname(s);
1164 }
1165
1166 /**
1167  * v9fs_vfs_mkspecial - create a special file
1168  * @dir: inode to create special file in
1169  * @dentry: dentry to create
1170  * @mode: mode to create special file
1171  * @extension: 9p2000.u format extension string representing special file
1172  *
1173  */
1174
1175 static int v9fs_vfs_mkspecial(struct inode *dir, struct dentry *dentry,
1176         int mode, const char *extension)
1177 {
1178         u32 perm;
1179         struct v9fs_session_info *v9ses;
1180         struct p9_fid *fid;
1181
1182         v9ses = v9fs_inode2v9ses(dir);
1183         if (!v9fs_proto_dotu(v9ses)) {
1184                 P9_DPRINTK(P9_DEBUG_ERROR, "not extended\n");
1185                 return -EPERM;
1186         }
1187
1188         perm = unixmode2p9mode(v9ses, mode);
1189         fid = v9fs_create(v9ses, dir, dentry, (char *) extension, perm,
1190                                                                 P9_OREAD);
1191         if (IS_ERR(fid))
1192                 return PTR_ERR(fid);
1193
1194         p9_client_clunk(fid);
1195         return 0;
1196 }
1197
1198 /**
1199  * v9fs_vfs_symlink - helper function to create symlinks
1200  * @dir: directory inode containing symlink
1201  * @dentry: dentry for symlink
1202  * @symname: symlink data
1203  *
1204  * See Also: 9P2000.u RFC for more information
1205  *
1206  */
1207
1208 static int
1209 v9fs_vfs_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
1210 {
1211         P9_DPRINTK(P9_DEBUG_VFS, " %lu,%s,%s\n", dir->i_ino,
1212                                         dentry->d_name.name, symname);
1213
1214         return v9fs_vfs_mkspecial(dir, dentry, S_IFLNK, symname);
1215 }
1216
1217 /**
1218  * v9fs_vfs_link - create a hardlink
1219  * @old_dentry: dentry for file to link to
1220  * @dir: inode destination for new link
1221  * @dentry: dentry for link
1222  *
1223  */
1224
1225 static int
1226 v9fs_vfs_link(struct dentry *old_dentry, struct inode *dir,
1227               struct dentry *dentry)
1228 {
1229         int retval;
1230         struct p9_fid *oldfid;
1231         char *name;
1232
1233         P9_DPRINTK(P9_DEBUG_VFS,
1234                 " %lu,%s,%s\n", dir->i_ino, dentry->d_name.name,
1235                 old_dentry->d_name.name);
1236
1237         oldfid = v9fs_fid_clone(old_dentry);
1238         if (IS_ERR(oldfid))
1239                 return PTR_ERR(oldfid);
1240
1241         name = __getname();
1242         if (unlikely(!name)) {
1243                 retval = -ENOMEM;
1244                 goto clunk_fid;
1245         }
1246
1247         sprintf(name, "%d\n", oldfid->fid);
1248         retval = v9fs_vfs_mkspecial(dir, dentry, P9_DMLINK, name);
1249         __putname(name);
1250
1251 clunk_fid:
1252         p9_client_clunk(oldfid);
1253         return retval;
1254 }
1255
1256 /**
1257  * v9fs_vfs_mknod - create a special file
1258  * @dir: inode destination for new link
1259  * @dentry: dentry for file
1260  * @mode: mode for creation
1261  * @rdev: device associated with special file
1262  *
1263  */
1264
1265 static int
1266 v9fs_vfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t rdev)
1267 {
1268         int retval;
1269         char *name;
1270
1271         P9_DPRINTK(P9_DEBUG_VFS,
1272                 " %lu,%s mode: %x MAJOR: %u MINOR: %u\n", dir->i_ino,
1273                 dentry->d_name.name, mode, MAJOR(rdev), MINOR(rdev));
1274
1275         if (!new_valid_dev(rdev))
1276                 return -EINVAL;
1277
1278         name = __getname();
1279         if (!name)
1280                 return -ENOMEM;
1281         /* build extension */
1282         if (S_ISBLK(mode))
1283                 sprintf(name, "b %u %u", MAJOR(rdev), MINOR(rdev));
1284         else if (S_ISCHR(mode))
1285                 sprintf(name, "c %u %u", MAJOR(rdev), MINOR(rdev));
1286         else if (S_ISFIFO(mode))
1287                 *name = 0;
1288         else if (S_ISSOCK(mode))
1289                 *name = 0;
1290         else {
1291                 __putname(name);
1292                 return -EINVAL;
1293         }
1294
1295         retval = v9fs_vfs_mkspecial(dir, dentry, mode, name);
1296         __putname(name);
1297
1298         return retval;
1299 }
1300
1301 static const struct inode_operations v9fs_dir_inode_operations_dotu = {
1302         .create = v9fs_vfs_create,
1303         .lookup = v9fs_vfs_lookup,
1304         .symlink = v9fs_vfs_symlink,
1305         .link = v9fs_vfs_link,
1306         .unlink = v9fs_vfs_unlink,
1307         .mkdir = v9fs_vfs_mkdir,
1308         .rmdir = v9fs_vfs_rmdir,
1309         .mknod = v9fs_vfs_mknod,
1310         .rename = v9fs_vfs_rename,
1311         .getattr = v9fs_vfs_getattr,
1312         .setattr = v9fs_vfs_setattr,
1313 };
1314
1315 static const struct inode_operations v9fs_dir_inode_operations = {
1316         .create = v9fs_vfs_create,
1317         .lookup = v9fs_vfs_lookup,
1318         .unlink = v9fs_vfs_unlink,
1319         .mkdir = v9fs_vfs_mkdir,
1320         .rmdir = v9fs_vfs_rmdir,
1321         .mknod = v9fs_vfs_mknod,
1322         .rename = v9fs_vfs_rename,
1323         .getattr = v9fs_vfs_getattr,
1324         .setattr = v9fs_vfs_setattr,
1325 };
1326
1327 static const struct inode_operations v9fs_file_inode_operations = {
1328         .getattr = v9fs_vfs_getattr,
1329         .setattr = v9fs_vfs_setattr,
1330 };
1331
1332 static const struct inode_operations v9fs_symlink_inode_operations = {
1333         .readlink = generic_readlink,
1334         .follow_link = v9fs_vfs_follow_link,
1335         .put_link = v9fs_vfs_put_link,
1336         .getattr = v9fs_vfs_getattr,
1337         .setattr = v9fs_vfs_setattr,
1338 };
1339