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 <net/9p/9p.h>
  39 #include <net/9p/client.h>
  40
  41 #include "v9fs.h"
  42 #include "v9fs_vfs.h"
  43 #include "fid.h"
  44 #include "cache.h"
  45
  46 static const struct inode_operations v9fs_dir_inode_operations;
  47 static const struct inode_operations v9fs_dir_inode_operations_ext;
  48 static const struct inode_operations v9fs_file_inode_operations;
  49 static const struct inode_operations v9fs_symlink_inode_operations;
  50
  51 /**
  52  * unixmode2p9mode - convert unix mode bits to plan 9
  53  * @v9ses: v9fs session information
  54  * @mode: mode to convert
  55  *
  56  */
  57
  58 static int unixmode2p9mode(struct v9fs_session_info *v9ses, int mode)
  59 {
  60         int res;
  61         res = mode & 0777;
  62         if (S_ISDIR(mode))
  63                 res |= P9_DMDIR;
  64         if (v9fs_proto_dotu(v9ses)) {
  65                 if (S_ISLNK(mode))
  66                         res |= P9_DMSYMLINK;
  67                 if (v9ses->nodev == 0) {
  68                         if (S_ISSOCK(mode))
  69                                 res |= P9_DMSOCKET;
  70                         if (S_ISFIFO(mode))
  71                                 res |= P9_DMNAMEDPIPE;
  72                         if (S_ISBLK(mode))
  73                                 res |= P9_DMDEVICE;
  74                         if (S_ISCHR(mode))
  75                                 res |= P9_DMDEVICE;
  76                 }
  77
  78                 if ((mode & S_ISUID) == S_ISUID)
  79                         res |= P9_DMSETUID;
  80                 if ((mode & S_ISGID) == S_ISGID)
  81                         res |= P9_DMSETGID;
  82                 if ((mode & S_ISVTX) == S_ISVTX)
  83                         res |= P9_DMSETVTX;
  84                 if ((mode & P9_DMLINK))
  85                         res |= P9_DMLINK;
  86         }
  87
  88         return res;
  89 }
  90
  91 /**
  92  * p9mode2unixmode- convert plan9 mode bits to unix mode bits
  93  * @v9ses: v9fs session information
  94  * @mode: mode to convert
  95  *
  96  */
  97
  98 static int p9mode2unixmode(struct v9fs_session_info *v9ses, int mode)
  99 {
 100         int res;
 101
 102         res = mode & 0777;
 103
 104         if ((mode & P9_DMDIR) == P9_DMDIR)
 105                 res |= S_IFDIR;
 106         else if ((mode & P9_DMSYMLINK) && (v9fs_proto_dotu(v9ses)))
 107                 res |= S_IFLNK;
 108         else if ((mode & P9_DMSOCKET) && (v9fs_proto_dotu(v9ses))
 109                  && (v9ses->nodev == 0))
 110                 res |= S_IFSOCK;
 111         else if ((mode & P9_DMNAMEDPIPE) && (v9fs_proto_dotu(v9ses))
 112                  && (v9ses->nodev == 0))
 113                 res |= S_IFIFO;
 114         else if ((mode & P9_DMDEVICE) && (v9fs_proto_dotu(v9ses))
 115                  && (v9ses->nodev == 0))
 116                 res |= S_IFBLK;
 117         else
 118                 res |= S_IFREG;
 119
 120         if (v9fs_proto_dotu(v9ses)) {
 121                 if ((mode & P9_DMSETUID) == P9_DMSETUID)
 122                         res |= S_ISUID;
 123
 124                 if ((mode & P9_DMSETGID) == P9_DMSETGID)
 125                         res |= S_ISGID;
 126
 127                 if ((mode & P9_DMSETVTX) == P9_DMSETVTX)
 128                         res |= S_ISVTX;
 129         }
 130
 131         return res;
 132 }
 133
 134 /**
 135  * v9fs_uflags2omode- convert posix open flags to plan 9 mode bits
 136  * @uflags: flags to convert
 137  * @extended: if .u extensions are active
 138  */
 139
 140 int v9fs_uflags2omode(int uflags, int extended)
 141 {
 142         int ret;
 143
 144         ret = 0;
 145         switch (uflags&3) {
 146         default:
 147         case O_RDONLY:
 148                 ret = P9_OREAD;
 149                 break;
 150
 151         case O_WRONLY:
 152                 ret = P9_OWRITE;
 153                 break;
 154
 155         case O_RDWR:
 156                 ret = P9_ORDWR;
 157                 break;
 158         }
 159
 160         if (uflags & O_TRUNC)
 161                 ret |= P9_OTRUNC;
 162
 163         if (extended) {
 164                 if (uflags & O_EXCL)
 165                         ret |= P9_OEXCL;
 166
 167                 if (uflags & O_APPEND)
 168                         ret |= P9_OAPPEND;
 169         }
 170
 171         return ret;
 172 }
 173
 174 /**
 175  * v9fs_blank_wstat - helper function to setup a 9P stat structure
 176  * @wstat: structure to initialize
 177  *
 178  */
 179
 180 void
 181 v9fs_blank_wstat(struct p9_wstat *wstat)
 182 {
 183         wstat->type = ~0;
 184         wstat->dev = ~0;
 185         wstat->qid.type = ~0;
 186         wstat->qid.version = ~0;
 187         *((long long *)&wstat->qid.path) = ~0;
 188         wstat->mode = ~0;
 189         wstat->atime = ~0;
 190         wstat->mtime = ~0;
 191         wstat->length = ~0;
 192         wstat->name = NULL;
 193         wstat->uid = NULL;
 194         wstat->gid = NULL;
 195         wstat->muid = NULL;
 196         wstat->n_uid = ~0;
 197         wstat->n_gid = ~0;
 198         wstat->n_muid = ~0;
 199         wstat->extension = NULL;
 200 }
 201
 202 #ifdef CONFIG_9P_FSCACHE
 203 /**
 204  * v9fs_alloc_inode - helper function to allocate an inode
 205  * This callback is executed before setting up the inode so that we
 206  * can associate a vcookie with each inode.
 207  *
 208  */
 209
 210 struct inode *v9fs_alloc_inode(struct super_block *sb)
 211 {
 212         struct v9fs_cookie *vcookie;
 213         vcookie = (struct v9fs_cookie *)kmem_cache_alloc(vcookie_cache,
 214                                                          GFP_KERNEL);
 215         if (!vcookie)
 216                 return NULL;
 217
 218         vcookie->fscache = NULL;
 219         vcookie->qid = NULL;
 220         spin_lock_init(&vcookie->lock);
 221         return &vcookie->inode;
 222 }
 223
 224 /**
 225  * v9fs_destroy_inode - destroy an inode
 226  *
 227  */
 228
 229 void v9fs_destroy_inode(struct inode *inode)
 230 {
 231         kmem_cache_free(vcookie_cache, v9fs_inode2cookie(inode));
 232 }
 233 #endif
 234
 235 /**
 236  * v9fs_get_inode - helper function to setup an inode
 237  * @sb: superblock
 238  * @mode: mode to setup inode with
 239  *
 240  */
 241
 242 struct inode *v9fs_get_inode(struct super_block *sb, int mode)
 243 {
 244         int err;
 245         struct inode *inode;
 246         struct v9fs_session_info *v9ses = sb->s_fs_info;
 247
 248         P9_DPRINTK(P9_DEBUG_VFS, "super block: %p mode: %o\n", sb, mode);
 249
 250         inode = new_inode(sb);
 251         if (!inode) {
 252                 P9_EPRINTK(KERN_WARNING, "Problem allocating inode\n");
 253                 return ERR_PTR(-ENOMEM);
 254         }
 255
 256         inode->i_mode = mode;
 257         inode->i_uid = current_fsuid();
 258         inode->i_gid = current_fsgid();
 259         inode->i_blocks = 0;
 260         inode->i_rdev = 0;
 261         inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 262         inode->i_mapping->a_ops = &v9fs_addr_operations;
 263
 264         switch (mode & S_IFMT) {
 265         case S_IFIFO:
 266         case S_IFBLK:
 267         case S_IFCHR:
 268         case S_IFSOCK:
 269                 if (!v9fs_proto_dotu(v9ses)) {
 270                         P9_DPRINTK(P9_DEBUG_ERROR,
 271                                    "special files without extended mode\n");
 272                         err = -EINVAL;
 273                         goto error;
 274                 }
 275                 init_special_inode(inode, inode->i_mode, inode->i_rdev);
 276                 break;
 277         case S_IFREG:
 278                 inode->i_op = &v9fs_file_inode_operations;
 279                 inode->i_fop = &v9fs_file_operations;
 280                 break;
 281         case S_IFLNK:
 282                 if (!v9fs_proto_dotu(v9ses)) {
 283                         P9_DPRINTK(P9_DEBUG_ERROR,
 284                                    "extended modes used w/o 9P2000.u\n");
 285                         err = -EINVAL;
 286                         goto error;
 287                 }
 288                 inode->i_op = &v9fs_symlink_inode_operations;
 289                 break;
 290         case S_IFDIR:
 291                 inc_nlink(inode);
 292                 if (v9fs_proto_dotu(v9ses))
 293                         inode->i_op = &v9fs_dir_inode_operations_ext;
 294                 else
 295                         inode->i_op = &v9fs_dir_inode_operations;
 296                 inode->i_fop = &v9fs_dir_operations;
 297                 break;
 298         default:
 299                 P9_DPRINTK(P9_DEBUG_ERROR, "BAD mode 0x%x S_IFMT 0x%x\n",
 300                            mode, mode & S_IFMT);
 301                 err = -EINVAL;
 302                 goto error;
 303         }
 304
 305         return inode;
 306
 307 error:
 308         iput(inode);
 309         return ERR_PTR(err);
 310 }
 311
 312 /*
 313 static struct v9fs_fid*
 314 v9fs_clone_walk(struct v9fs_session_info *v9ses, u32 fid, struct dentry *dentry)
 315 {
 316         int err;
 317         int nfid;
 318         struct v9fs_fid *ret;
 319         struct v9fs_fcall *fcall;
 320
 321         nfid = v9fs_get_idpool(&v9ses->fidpool);
 322         if (nfid < 0) {
 323                 eprintk(KERN_WARNING, "no free fids available\n");
 324                 return ERR_PTR(-ENOSPC);
 325         }
 326
 327         err = v9fs_t_walk(v9ses, fid, nfid, (char *) dentry->d_name.name,
 328                 &fcall);
 329
 330         if (err < 0) {
 331                 if (fcall && fcall->id == RWALK)
 332                         goto clunk_fid;
 333
 334                 PRINT_FCALL_ERROR("walk error", fcall);
 335                 v9fs_put_idpool(nfid, &v9ses->fidpool);
 336                 goto error;
 337         }
 338
 339         kfree(fcall);
 340         fcall = NULL;
 341         ret = v9fs_fid_create(v9ses, nfid);
 342         if (!ret) {
 343                 err = -ENOMEM;
 344                 goto clunk_fid;
 345         }
 346
 347         err = v9fs_fid_insert(ret, dentry);
 348         if (err < 0) {
 349                 v9fs_fid_destroy(ret);
 350                 goto clunk_fid;
 351         }
 352
 353         return ret;
 354
 355 clunk_fid:
 356         v9fs_t_clunk(v9ses, nfid);
 357
 358 error:
 359         kfree(fcall);
 360         return ERR_PTR(err);
 361 }
 362 */
 363
 364
 365 /**
 366  * v9fs_clear_inode - release an inode
 367  * @inode: inode to release
 368  *
 369  */
 370 void v9fs_clear_inode(struct inode *inode)
 371 {
 372         filemap_fdatawrite(inode->i_mapping);
 373
 374 #ifdef CONFIG_9P_FSCACHE
 375         v9fs_cache_inode_put_cookie(inode);
 376 #endif
 377 }
 378
 379 /**
 380  * v9fs_inode_from_fid - populate an inode by issuing a attribute request
 381  * @v9ses: session information
 382  * @fid: fid to issue attribute request for
 383  * @sb: superblock on which to create inode
 384  *
 385  */
 386
 387 static struct inode *
 388 v9fs_inode_from_fid(struct v9fs_session_info *v9ses, struct p9_fid *fid,
 389         struct super_block *sb)
 390 {
 391         int err, umode;
 392         struct inode *ret;
 393         struct p9_wstat *st;
 394
 395         ret = NULL;
 396         st = p9_client_stat(fid);
 397         if (IS_ERR(st))
 398                 return ERR_CAST(st);
 399
 400         umode = p9mode2unixmode(v9ses, st->mode);
 401         ret = v9fs_get_inode(sb, umode);
 402         if (IS_ERR(ret)) {
 403                 err = PTR_ERR(ret);
 404                 goto error;
 405         }
 406
 407         v9fs_stat2inode(st, ret, sb);
 408         ret->i_ino = v9fs_qid2ino(&st->qid);
 409
 410 #ifdef CONFIG_9P_FSCACHE
 411         v9fs_vcookie_set_qid(ret, &st->qid);
 412         v9fs_cache_inode_get_cookie(ret);
 413 #endif
 414         p9stat_free(st);
 415         kfree(st);
 416
 417         return ret;
 418
 419 error:
 420         p9stat_free(st);
 421         kfree(st);
 422         return ERR_PTR(err);
 423 }
 424
 425 /**
 426  * v9fs_remove - helper function to remove files and directories
 427  * @dir: directory inode that is being deleted
 428  * @file:  dentry that is being deleted
 429  * @rmdir: removing a directory
 430  *
 431  */
 432
 433 static int v9fs_remove(struct inode *dir, struct dentry *file, int rmdir)
 434 {
 435         int retval;
 436         struct inode *file_inode;
 437         struct v9fs_session_info *v9ses;
 438         struct p9_fid *v9fid;
 439
 440         P9_DPRINTK(P9_DEBUG_VFS, "inode: %p dentry: %p rmdir: %d\n", dir, file,
 441                 rmdir);
 442
 443         file_inode = file->d_inode;
 444         v9ses = v9fs_inode2v9ses(file_inode);
 445         v9fid = v9fs_fid_clone(file);
 446         if (IS_ERR(v9fid))
 447                 return PTR_ERR(v9fid);
 448
 449         retval = p9_client_remove(v9fid);
 450         if (!retval)
 451                 drop_nlink(file_inode);
 452         return retval;
 453 }
 454
 455 static int
 456 v9fs_open_created(struct inode *inode, struct file *file)
 457 {
 458         return 0;
 459 }
 460
 461
 462 /**
 463  * v9fs_create - Create a file
 464  * @v9ses: session information
 465  * @dir: directory that dentry is being created in
 466  * @dentry:  dentry that is being created
 467  * @extension: 9p2000.u extension string to support devices, etc.
 468  * @perm: create permissions
 469  * @mode: open mode
 470  *
 471  */
 472 static struct p9_fid *
 473 v9fs_create(struct v9fs_session_info *v9ses, struct inode *dir,
 474                 struct dentry *dentry, char *extension, u32 perm, u8 mode)
 475 {
 476         int err;
 477         char *name;
 478         struct p9_fid *dfid, *ofid, *fid;
 479         struct inode *inode;
 480
 481         P9_DPRINTK(P9_DEBUG_VFS, "name %s\n", dentry->d_name.name);
 482
 483         err = 0;
 484         ofid = NULL;
 485         fid = NULL;
 486         name = (char *) dentry->d_name.name;
 487         dfid = v9fs_fid_clone(dentry->d_parent);
 488         if (IS_ERR(dfid)) {
 489                 err = PTR_ERR(dfid);
 490                 P9_DPRINTK(P9_DEBUG_VFS, "fid clone failed %d\n", err);
 491                 dfid = NULL;
 492                 goto error;
 493         }
 494
 495         /* clone a fid to use for creation */
 496         ofid = p9_client_walk(dfid, 0, NULL, 1);
 497         if (IS_ERR(ofid)) {
 498                 err = PTR_ERR(ofid);
 499                 P9_DPRINTK(P9_DEBUG_VFS, "p9_client_walk failed %d\n", err);
 500                 ofid = NULL;
 501                 goto error;
 502         }
 503
 504         err = p9_client_fcreate(ofid, name, perm, mode, extension);
 505         if (err < 0) {
 506                 P9_DPRINTK(P9_DEBUG_VFS, "p9_client_fcreate failed %d\n", err);
 507                 goto error;
 508         }
 509
 510         /* now walk from the parent so we can get unopened fid */
 511         fid = p9_client_walk(dfid, 1, &name, 0);
 512         if (IS_ERR(fid)) {
 513                 err = PTR_ERR(fid);
 514                 P9_DPRINTK(P9_DEBUG_VFS, "p9_client_walk failed %d\n", err);
 515                 fid = NULL;
 516                 goto error;
 517         } else
 518                 dfid = NULL;
 519
 520         /* instantiate inode and assign the unopened fid to the dentry */
 521         inode = v9fs_inode_from_fid(v9ses, fid, dir->i_sb);
 522         if (IS_ERR(inode)) {
 523                 err = PTR_ERR(inode);
 524                 P9_DPRINTK(P9_DEBUG_VFS, "inode creation failed %d\n", err);
 525                 goto error;
 526         }
 527
 528         if (v9ses->cache)
 529                 dentry->d_op = &v9fs_cached_dentry_operations;
 530         else
 531                 dentry->d_op = &v9fs_dentry_operations;
 532
 533         d_instantiate(dentry, inode);
 534         err = v9fs_fid_add(dentry, fid);
 535         if (err < 0)
 536                 goto error;
 537
 538         return ofid;
 539
 540 error:
 541         if (dfid)
 542                 p9_client_clunk(dfid);
 543
 544         if (ofid)
 545                 p9_client_clunk(ofid);
 546
 547         if (fid)
 548                 p9_client_clunk(fid);
 549
 550         return ERR_PTR(err);
 551 }
 552
 553 /**
 554  * v9fs_vfs_create - VFS hook to create files
 555  * @dir: directory inode that is being created
 556  * @dentry:  dentry that is being deleted
 557  * @mode: create permissions
 558  * @nd: path information
 559  *
 560  */
 561
 562 static int
 563 v9fs_vfs_create(struct inode *dir, struct dentry *dentry, int mode,
 564                 struct nameidata *nd)
 565 {
 566         int err;
 567         u32 perm;
 568         int flags;
 569         struct v9fs_session_info *v9ses;
 570         struct p9_fid *fid;
 571         struct file *filp;
 572
 573         err = 0;
 574         fid = NULL;
 575         v9ses = v9fs_inode2v9ses(dir);
 576         perm = unixmode2p9mode(v9ses, mode);
 577         if (nd && nd->flags & LOOKUP_OPEN)
 578                 flags = nd->intent.open.flags - 1;
 579         else
 580                 flags = O_RDWR;
 581
 582         fid = v9fs_create(v9ses, dir, dentry, NULL, perm,
 583                                 v9fs_uflags2omode(flags,
 584                                                 v9fs_proto_dotu(v9ses)));
 585         if (IS_ERR(fid)) {
 586                 err = PTR_ERR(fid);
 587                 fid = NULL;
 588                 goto error;
 589         }
 590
 591         /* if we are opening a file, assign the open fid to the file */
 592         if (nd && nd->flags & LOOKUP_OPEN) {
 593                 filp = lookup_instantiate_filp(nd, dentry, v9fs_open_created);
 594                 if (IS_ERR(filp)) {
 595                         err = PTR_ERR(filp);
 596                         goto error;
 597                 }
 598
 599                 filp->private_data = fid;
 600         } else
 601                 p9_client_clunk(fid);
 602
 603         return 0;
 604
 605 error:
 606         if (fid)
 607                 p9_client_clunk(fid);
 608
 609         return err;
 610 }
 611
 612 /**
 613  * v9fs_vfs_mkdir - VFS mkdir hook to create a directory
 614  * @dir:  inode that is being unlinked
 615  * @dentry: dentry that is being unlinked
 616  * @mode: mode for new directory
 617  *
 618  */
 619
 620 static int v9fs_vfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 621 {
 622         int err;
 623         u32 perm;
 624         struct v9fs_session_info *v9ses;
 625         struct p9_fid *fid;
 626
 627         P9_DPRINTK(P9_DEBUG_VFS, "name %s\n", dentry->d_name.name);
 628         err = 0;
 629         v9ses = v9fs_inode2v9ses(dir);
 630         perm = unixmode2p9mode(v9ses, mode | S_IFDIR);
 631         fid = v9fs_create(v9ses, dir, dentry, NULL, perm, P9_OREAD);
 632         if (IS_ERR(fid)) {
 633                 err = PTR_ERR(fid);
 634                 fid = NULL;
 635         }
 636
 637         if (fid)
 638                 p9_client_clunk(fid);
 639
 640         return err;
 641 }
 642
 643 /**
 644  * v9fs_vfs_lookup - VFS lookup hook to "walk" to a new inode
 645  * @dir:  inode that is being walked from
 646  * @dentry: dentry that is being walked to?
 647  * @nameidata: path data
 648  *
 649  */
 650
 651 static struct dentry *v9fs_vfs_lookup(struct inode *dir, struct dentry *dentry,
 652                                       struct nameidata *nameidata)
 653 {
 654         struct super_block *sb;
 655         struct v9fs_session_info *v9ses;
 656         struct p9_fid *dfid, *fid;
 657         struct inode *inode;
 658         char *name;
 659         int result = 0;
 660
 661         P9_DPRINTK(P9_DEBUG_VFS, "dir: %p dentry: (%s) %p nameidata: %p\n",
 662                 dir, dentry->d_name.name, dentry, nameidata);
 663
 664         if (dentry->d_name.len > NAME_MAX)
 665                 return ERR_PTR(-ENAMETOOLONG);
 666
 667         sb = dir->i_sb;
 668         v9ses = v9fs_inode2v9ses(dir);
 669         dfid = v9fs_fid_lookup(dentry->d_parent);
 670         if (IS_ERR(dfid))
 671                 return ERR_CAST(dfid);
 672
 673         name = (char *) dentry->d_name.name;
 674         fid = p9_client_walk(dfid, 1, &name, 1);
 675         if (IS_ERR(fid)) {
 676                 result = PTR_ERR(fid);
 677                 if (result == -ENOENT) {
 678                         d_add(dentry, NULL);
 679                         return NULL;
 680                 }
 681
 682                 return ERR_PTR(result);
 683         }
 684
 685         inode = v9fs_inode_from_fid(v9ses, fid, dir->i_sb);
 686         if (IS_ERR(inode)) {
 687                 result = PTR_ERR(inode);
 688                 inode = NULL;
 689                 goto error;
 690         }
 691
 692         result = v9fs_fid_add(dentry, fid);
 693         if (result < 0)
 694                 goto error;
 695
 696         if ((fid->qid.version) && (v9ses->cache))
 697                 dentry->d_op = &v9fs_cached_dentry_operations;
 698         else
 699                 dentry->d_op = &v9fs_dentry_operations;
 700
 701         d_add(dentry, inode);
 702         return NULL;
 703
 704 error:
 705         p9_client_clunk(fid);
 706
 707         return ERR_PTR(result);
 708 }
 709
 710 /**
 711  * v9fs_vfs_unlink - VFS unlink hook to delete an inode
 712  * @i:  inode that is being unlinked
 713  * @d: dentry that is being unlinked
 714  *
 715  */
 716
 717 static int v9fs_vfs_unlink(struct inode *i, struct dentry *d)
 718 {
 719         return v9fs_remove(i, d, 0);
 720 }
 721
 722 /**
 723  * v9fs_vfs_rmdir - VFS unlink hook to delete a directory
 724  * @i:  inode that is being unlinked
 725  * @d: dentry that is being unlinked
 726  *
 727  */
 728
 729 static int v9fs_vfs_rmdir(struct inode *i, struct dentry *d)
 730 {
 731         return v9fs_remove(i, d, 1);
 732 }
 733
 734 /**
 735  * v9fs_vfs_rename - VFS hook to rename an inode
 736  * @old_dir:  old dir inode
 737  * @old_dentry: old dentry
 738  * @new_dir: new dir inode
 739  * @new_dentry: new dentry
 740  *
 741  */
 742
 743 static int
 744 v9fs_vfs_rename(struct inode *old_dir, struct dentry *old_dentry,
 745                 struct inode *new_dir, struct dentry *new_dentry)
 746 {
 747         struct inode *old_inode;
 748         struct v9fs_session_info *v9ses;
 749         struct p9_fid *oldfid;
 750         struct p9_fid *olddirfid;
 751         struct p9_fid *newdirfid;
 752         struct p9_wstat wstat;
 753         int retval;
 754
 755         P9_DPRINTK(P9_DEBUG_VFS, "\n");
 756         retval = 0;
 757         old_inode = old_dentry->d_inode;
 758         v9ses = v9fs_inode2v9ses(old_inode);
 759         oldfid = v9fs_fid_lookup(old_dentry);
 760         if (IS_ERR(oldfid))
 761                 return PTR_ERR(oldfid);
 762
 763         olddirfid = v9fs_fid_clone(old_dentry->d_parent);
 764         if (IS_ERR(olddirfid)) {
 765                 retval = PTR_ERR(olddirfid);
 766                 goto done;
 767         }
 768
 769         newdirfid = v9fs_fid_clone(new_dentry->d_parent);
 770         if (IS_ERR(newdirfid)) {
 771                 retval = PTR_ERR(newdirfid);
 772                 goto clunk_olddir;
 773         }
 774
 775         /* 9P can only handle file rename in the same directory */
 776         if (memcmp(&olddirfid->qid, &newdirfid->qid, sizeof(newdirfid->qid))) {
 777                 P9_DPRINTK(P9_DEBUG_ERROR,
 778                                 "old dir and new dir are different\n");
 779                 retval = -EXDEV;
 780                 goto clunk_newdir;
 781         }
 782
 783         v9fs_blank_wstat(&wstat);
 784         wstat.muid = v9ses->uname;
 785         wstat.name = (char *) new_dentry->d_name.name;
 786         retval = p9_client_wstat(oldfid, &wstat);
 787
 788 clunk_newdir:
 789         p9_client_clunk(newdirfid);
 790
 791 clunk_olddir:
 792         p9_client_clunk(olddirfid);
 793
 794 done:
 795         return retval;
 796 }
 797
 798 /**
 799  * v9fs_vfs_getattr - retrieve file metadata
 800  * @mnt: mount information
 801  * @dentry: file to get attributes on
 802  * @stat: metadata structure to populate
 803  *
 804  */
 805
 806 static int
 807 v9fs_vfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
 808                  struct kstat *stat)
 809 {
 810         int err;
 811         struct v9fs_session_info *v9ses;
 812         struct p9_fid *fid;
 813         struct p9_wstat *st;
 814
 815         P9_DPRINTK(P9_DEBUG_VFS, "dentry: %p\n", dentry);
 816         err = -EPERM;
 817         v9ses = v9fs_inode2v9ses(dentry->d_inode);
 818         if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
 819                 return simple_getattr(mnt, dentry, stat);
 820
 821         fid = v9fs_fid_lookup(dentry);
 822         if (IS_ERR(fid))
 823                 return PTR_ERR(fid);
 824
 825         st = p9_client_stat(fid);
 826         if (IS_ERR(st))
 827                 return PTR_ERR(st);
 828
 829         v9fs_stat2inode(st, dentry->d_inode, dentry->d_inode->i_sb);
 830                 generic_fillattr(dentry->d_inode, stat);
 831
 832         kfree(st);
 833         return 0;
 834 }
 835
 836 /**
 837  * v9fs_vfs_setattr - set file metadata
 838  * @dentry: file whose metadata to set
 839  * @iattr: metadata assignment structure
 840  *
 841  */
 842
 843 static int v9fs_vfs_setattr(struct dentry *dentry, struct iattr *iattr)
 844 {
 845         int retval;
 846         struct v9fs_session_info *v9ses;
 847         struct p9_fid *fid;
 848         struct p9_wstat wstat;
 849
 850         P9_DPRINTK(P9_DEBUG_VFS, "\n");
 851         retval = -EPERM;
 852         v9ses = v9fs_inode2v9ses(dentry->d_inode);
 853         fid = v9fs_fid_lookup(dentry);
 854         if(IS_ERR(fid))
 855                 return PTR_ERR(fid);
 856
 857         v9fs_blank_wstat(&wstat);
 858         if (iattr->ia_valid & ATTR_MODE)
 859                 wstat.mode = unixmode2p9mode(v9ses, iattr->ia_mode);
 860
 861         if (iattr->ia_valid & ATTR_MTIME)
 862                 wstat.mtime = iattr->ia_mtime.tv_sec;
 863
 864         if (iattr->ia_valid & ATTR_ATIME)
 865                 wstat.atime = iattr->ia_atime.tv_sec;
 866
 867         if (iattr->ia_valid & ATTR_SIZE)
 868                 wstat.length = iattr->ia_size;
 869
 870         if (v9fs_proto_dotu(v9ses)) {
 871                 if (iattr->ia_valid & ATTR_UID)
 872                         wstat.n_uid = iattr->ia_uid;
 873
 874                 if (iattr->ia_valid & ATTR_GID)
 875                         wstat.n_gid = iattr->ia_gid;
 876         }
 877
 878         retval = p9_client_wstat(fid, &wstat);
 879         if (retval >= 0)
 880                 retval = inode_setattr(dentry->d_inode, iattr);
 881
 882         return retval;
 883 }
 884
 885 /**
 886  * v9fs_stat2inode - populate an inode structure with mistat info
 887  * @stat: Plan 9 metadata (mistat) structure
 888  * @inode: inode to populate
 889  * @sb: superblock of filesystem
 890  *
 891  */
 892
 893 void
 894 v9fs_stat2inode(struct p9_wstat *stat, struct inode *inode,
 895         struct super_block *sb)
 896 {
 897         char ext[32];
 898         char tag_name[14];
 899         unsigned int i_nlink;
 900         struct v9fs_session_info *v9ses = sb->s_fs_info;
 901
 902         inode->i_nlink = 1;
 903
 904         inode->i_atime.tv_sec = stat->atime;
 905         inode->i_mtime.tv_sec = stat->mtime;
 906         inode->i_ctime.tv_sec = stat->mtime;
 907
 908         inode->i_uid = v9ses->dfltuid;
 909         inode->i_gid = v9ses->dfltgid;
 910
 911         if (v9fs_proto_dotu(v9ses)) {
 912                 inode->i_uid = stat->n_uid;
 913                 inode->i_gid = stat->n_gid;
 914         }
 915         if ((S_ISREG(inode->i_mode)) || (S_ISDIR(inode->i_mode))) {
 916                 if (v9fs_proto_dotu(v9ses) && (stat->extension[0] != '\0')) {
 917                         /*
 918                          * Hadlink support got added later to
 919                          * to the .u extension. So there can be
 920                          * server out there that doesn't support
 921                          * this even with .u extension. So check
 922                          * for non NULL stat->extension
 923                          */
 924                         strncpy(ext, stat->extension, sizeof(ext));
 925                         /* HARDLINKCOUNT %u */
 926                         sscanf(ext, "%13s %u", tag_name, &i_nlink);
 927                         if (!strncmp(tag_name, "HARDLINKCOUNT", 13))
 928                                 inode->i_nlink = i_nlink;
 929                 }
 930         }
 931         inode->i_mode = p9mode2unixmode(v9ses, stat->mode);
 932         if ((S_ISBLK(inode->i_mode)) || (S_ISCHR(inode->i_mode))) {
 933                 char type = 0;
 934                 int major = -1;
 935                 int minor = -1;
 936
 937                 strncpy(ext, stat->extension, sizeof(ext));
 938                 sscanf(ext, "%c %u %u", &type, &major, &minor);
 939                 switch (type) {
 940                 case 'c':
 941                         inode->i_mode &= ~S_IFBLK;
 942                         inode->i_mode |= S_IFCHR;
 943                         break;
 944                 case 'b':
 945                         break;
 946                 default:
 947                         P9_DPRINTK(P9_DEBUG_ERROR,
 948                                 "Unknown special type %c %s\n", type,
 949                                 stat->extension);
 950                 };
 951                 inode->i_rdev = MKDEV(major, minor);
 952                 init_special_inode(inode, inode->i_mode, inode->i_rdev);
 953         } else
 954                 inode->i_rdev = 0;
 955
 956         i_size_write(inode, stat->length);
 957
 958         /* not real number of blocks, but 512 byte ones ... */
 959         inode->i_blocks = (i_size_read(inode) + 512 - 1) >> 9;
 960 }
 961
 962 /**
 963  * v9fs_qid2ino - convert qid into inode number
 964  * @qid: qid to hash
 965  *
 966  * BUG: potential for inode number collisions?
 967  */
 968
 969 ino_t v9fs_qid2ino(struct p9_qid *qid)
 970 {
 971         u64 path = qid->path + 2;
 972         ino_t i = 0;
 973
 974         if (sizeof(ino_t) == sizeof(path))
 975                 memcpy(&i, &path, sizeof(ino_t));
 976         else
 977                 i = (ino_t) (path ^ (path >> 32));
 978
 979         return i;
 980 }
 981
 982 /**
 983  * v9fs_readlink - read a symlink's location (internal version)
 984  * @dentry: dentry for symlink
 985  * @buffer: buffer to load symlink location into
 986  * @buflen: length of buffer
 987  *
 988  */
 989
 990 static int v9fs_readlink(struct dentry *dentry, char *buffer, int buflen)
 991 {
 992         int retval;
 993
 994         struct v9fs_session_info *v9ses;
 995         struct p9_fid *fid;
 996         struct p9_wstat *st;
 997
 998         P9_DPRINTK(P9_DEBUG_VFS, " %s\n", dentry->d_name.name);
 999         retval = -EPERM;
1000         v9ses = v9fs_inode2v9ses(dentry->d_inode);
1001         fid = v9fs_fid_lookup(dentry);
1002         if (IS_ERR(fid))
1003                 return PTR_ERR(fid);
1004
1005         if (!v9fs_proto_dotu(v9ses))
1006                 return -EBADF;
1007
1008         st = p9_client_stat(fid);
1009         if (IS_ERR(st))
1010                 return PTR_ERR(st);
1011
1012         if (!(st->mode & P9_DMSYMLINK)) {
1013                 retval = -EINVAL;
1014                 goto done;
1015         }
1016
1017         /* copy extension buffer into buffer */
1018         strncpy(buffer, st->extension, buflen);
1019
1020         P9_DPRINTK(P9_DEBUG_VFS,
1021                 "%s -> %s (%s)\n", dentry->d_name.name, st->extension, buffer);
1022
1023         retval = strnlen(buffer, buflen);
1024 done:
1025         kfree(st);
1026         return retval;
1027 }
1028
1029 /**
1030  * v9fs_vfs_follow_link - follow a symlink path
1031  * @dentry: dentry for symlink
1032  * @nd: nameidata
1033  *
1034  */
1035
1036 static void *v9fs_vfs_follow_link(struct dentry *dentry, struct nameidata *nd)
1037 {
1038         int len = 0;
1039         char *link = __getname();
1040
1041         P9_DPRINTK(P9_DEBUG_VFS, "%s n", dentry->d_name.name);
1042
1043         if (!link)
1044                 link = ERR_PTR(-ENOMEM);
1045         else {
1046                 len = v9fs_readlink(dentry, link, PATH_MAX);
1047
1048                 if (len < 0) {
1049                         __putname(link);
1050                         link = ERR_PTR(len);
1051                 } else
1052                         link[min(len, PATH_MAX-1)] = 0;
1053         }
1054         nd_set_link(nd, link);
1055
1056         return NULL;
1057 }
1058
1059 /**
1060  * v9fs_vfs_put_link - release a symlink path
1061  * @dentry: dentry for symlink
1062  * @nd: nameidata
1063  * @p: unused
1064  *
1065  */
1066
1067 static void
1068 v9fs_vfs_put_link(struct dentry *dentry, struct nameidata *nd, void *p)
1069 {
1070         char *s = nd_get_link(nd);
1071
1072         P9_DPRINTK(P9_DEBUG_VFS, " %s %s\n", dentry->d_name.name,
1073                 IS_ERR(s) ? "<error>" : s);
1074         if (!IS_ERR(s))
1075                 __putname(s);
1076 }
1077
1078 /**
1079  * v9fs_vfs_mkspecial - create a special file
1080  * @dir: inode to create special file in
1081  * @dentry: dentry to create
1082  * @mode: mode to create special file
1083  * @extension: 9p2000.u format extension string representing special file
1084  *
1085  */
1086
1087 static int v9fs_vfs_mkspecial(struct inode *dir, struct dentry *dentry,
1088         int mode, const char *extension)
1089 {
1090         u32 perm;
1091         struct v9fs_session_info *v9ses;
1092         struct p9_fid *fid;
1093
1094         v9ses = v9fs_inode2v9ses(dir);
1095         if (!v9fs_proto_dotu(v9ses)) {
1096                 P9_DPRINTK(P9_DEBUG_ERROR, "not extended\n");
1097                 return -EPERM;
1098         }
1099
1100         perm = unixmode2p9mode(v9ses, mode);
1101         fid = v9fs_create(v9ses, dir, dentry, (char *) extension, perm,
1102                                                                 P9_OREAD);
1103         if (IS_ERR(fid))
1104                 return PTR_ERR(fid);
1105
1106         p9_client_clunk(fid);
1107         return 0;
1108 }
1109
1110 /**
1111  * v9fs_vfs_symlink - helper function to create symlinks
1112  * @dir: directory inode containing symlink
1113  * @dentry: dentry for symlink
1114  * @symname: symlink data
1115  *
1116  * See Also: 9P2000.u RFC for more information
1117  *
1118  */
1119
1120 static int
1121 v9fs_vfs_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
1122 {
1123         P9_DPRINTK(P9_DEBUG_VFS, " %lu,%s,%s\n", dir->i_ino,
1124                                         dentry->d_name.name, symname);
1125
1126         return v9fs_vfs_mkspecial(dir, dentry, S_IFLNK, symname);
1127 }
1128
1129 /**
1130  * v9fs_vfs_link - create a hardlink
1131  * @old_dentry: dentry for file to link to
1132  * @dir: inode destination for new link
1133  * @dentry: dentry for link
1134  *
1135  */
1136
1137 static int
1138 v9fs_vfs_link(struct dentry *old_dentry, struct inode *dir,
1139               struct dentry *dentry)
1140 {
1141         int retval;
1142         struct p9_fid *oldfid;
1143         char *name;
1144
1145         P9_DPRINTK(P9_DEBUG_VFS,
1146                 " %lu,%s,%s\n", dir->i_ino, dentry->d_name.name,
1147                 old_dentry->d_name.name);
1148
1149         oldfid = v9fs_fid_clone(old_dentry);
1150         if (IS_ERR(oldfid))
1151                 return PTR_ERR(oldfid);
1152
1153         name = __getname();
1154         if (unlikely(!name)) {
1155                 retval = -ENOMEM;
1156                 goto clunk_fid;
1157         }
1158
1159         sprintf(name, "%d\n", oldfid->fid);
1160         retval = v9fs_vfs_mkspecial(dir, dentry, P9_DMLINK, name);
1161         __putname(name);
1162
1163 clunk_fid:
1164         p9_client_clunk(oldfid);
1165         return retval;
1166 }
1167
1168 /**
1169  * v9fs_vfs_mknod - create a special file
1170  * @dir: inode destination for new link
1171  * @dentry: dentry for file
1172  * @mode: mode for creation
1173  * @rdev: device associated with special file
1174  *
1175  */
1176
1177 static int
1178 v9fs_vfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t rdev)
1179 {
1180         int retval;
1181         char *name;
1182
1183         P9_DPRINTK(P9_DEBUG_VFS,
1184                 " %lu,%s mode: %x MAJOR: %u MINOR: %u\n", dir->i_ino,
1185                 dentry->d_name.name, mode, MAJOR(rdev), MINOR(rdev));
1186
1187         if (!new_valid_dev(rdev))
1188                 return -EINVAL;
1189
1190         name = __getname();
1191         if (!name)
1192                 return -ENOMEM;
1193         /* build extension */
1194         if (S_ISBLK(mode))
1195                 sprintf(name, "b %u %u", MAJOR(rdev), MINOR(rdev));
1196         else if (S_ISCHR(mode))
1197                 sprintf(name, "c %u %u", MAJOR(rdev), MINOR(rdev));
1198         else if (S_ISFIFO(mode))
1199                 *name = 0;
1200         else {
1201                 __putname(name);
1202                 return -EINVAL;
1203         }
1204
1205         retval = v9fs_vfs_mkspecial(dir, dentry, mode, name);
1206         __putname(name);
1207
1208         return retval;
1209 }
1210
1211 static const struct inode_operations v9fs_dir_inode_operations_ext = {
1212         .create = v9fs_vfs_create,
1213         .lookup = v9fs_vfs_lookup,
1214         .symlink = v9fs_vfs_symlink,
1215         .link = v9fs_vfs_link,
1216         .unlink = v9fs_vfs_unlink,
1217         .mkdir = v9fs_vfs_mkdir,
1218         .rmdir = v9fs_vfs_rmdir,
1219         .mknod = v9fs_vfs_mknod,
1220         .rename = v9fs_vfs_rename,
1221         .getattr = v9fs_vfs_getattr,
1222         .setattr = v9fs_vfs_setattr,
1223 };
1224
1225 static const struct inode_operations v9fs_dir_inode_operations = {
1226         .create = v9fs_vfs_create,
1227         .lookup = v9fs_vfs_lookup,
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         .getattr = v9fs_vfs_getattr,
1234         .setattr = v9fs_vfs_setattr,
1235 };
1236
1237 static const struct inode_operations v9fs_file_inode_operations = {
1238         .getattr = v9fs_vfs_getattr,
1239         .setattr = v9fs_vfs_setattr,
1240 };
1241
1242 static const struct inode_operations v9fs_symlink_inode_operations = {
1243         .readlink = generic_readlink,
1244         .follow_link = v9fs_vfs_follow_link,
1245         .put_link = v9fs_vfs_put_link,
1246         .getattr = v9fs_vfs_getattr,
1247         .setattr = v9fs_vfs_setattr,
1248 };