fs/9p/vfs_inode.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  *  linux/fs/9p/vfs_inode.c
   4  *
   5  * This file contains vfs inode ops for the 9P2000 protocol.
   6  *
   7  *  Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
   8  *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
   9  */
  10
  11 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  12
  13 #include <linux/module.h>
  14 #include <linux/errno.h>
  15 #include <linux/fs.h>
  16 #include <linux/file.h>
  17 #include <linux/pagemap.h>
  18 #include <linux/stat.h>
  19 #include <linux/string.h>
  20 #include <linux/inet.h>
  21 #include <linux/namei.h>
  22 #include <linux/idr.h>
  23 #include <linux/sched.h>
  24 #include <linux/slab.h>
  25 #include <linux/xattr.h>
  26 #include <linux/posix_acl.h>
  27 #include <net/9p/9p.h>
  28 #include <net/9p/client.h>
  29
  30 #include "v9fs.h"
  31 #include "v9fs_vfs.h"
  32 #include "fid.h"
  33 #include "cache.h"
  34 #include "xattr.h"
  35 #include "acl.h"
  36
  37 static const struct inode_operations v9fs_dir_inode_operations;
  38 static const struct inode_operations v9fs_dir_inode_operations_dotu;
  39 static const struct inode_operations v9fs_file_inode_operations;
  40 static const struct inode_operations v9fs_symlink_inode_operations;
  41
  42 /**
  43  * unixmode2p9mode - convert unix mode bits to plan 9
  44  * @v9ses: v9fs session information
  45  * @mode: mode to convert
  46  *
  47  */
  48
  49 static u32 unixmode2p9mode(struct v9fs_session_info *v9ses, umode_t mode)
  50 {
  51         int res;
  52         res = mode & 0777;
  53         if (S_ISDIR(mode))
  54                 res |= P9_DMDIR;
  55         if (v9fs_proto_dotu(v9ses)) {
  56                 if (v9ses->nodev == 0) {
  57                         if (S_ISSOCK(mode))
  58                                 res |= P9_DMSOCKET;
  59                         if (S_ISFIFO(mode))
  60                                 res |= P9_DMNAMEDPIPE;
  61                         if (S_ISBLK(mode))
  62                                 res |= P9_DMDEVICE;
  63                         if (S_ISCHR(mode))
  64                                 res |= P9_DMDEVICE;
  65                 }
  66
  67                 if ((mode & S_ISUID) == S_ISUID)
  68                         res |= P9_DMSETUID;
  69                 if ((mode & S_ISGID) == S_ISGID)
  70                         res |= P9_DMSETGID;
  71                 if ((mode & S_ISVTX) == S_ISVTX)
  72                         res |= P9_DMSETVTX;
  73         }
  74         return res;
  75 }
  76
  77 /**
  78  * p9mode2perm- convert plan9 mode bits to unix permission bits
  79  * @v9ses: v9fs session information
  80  * @stat: p9_wstat from which mode need to be derived
  81  *
  82  */
  83 static int p9mode2perm(struct v9fs_session_info *v9ses,
  84                        struct p9_wstat *stat)
  85 {
  86         int res;
  87         int mode = stat->mode;
  88
  89         res = mode & S_IALLUGO;
  90         if (v9fs_proto_dotu(v9ses)) {
  91                 if ((mode & P9_DMSETUID) == P9_DMSETUID)
  92                         res |= S_ISUID;
  93
  94                 if ((mode & P9_DMSETGID) == P9_DMSETGID)
  95                         res |= S_ISGID;
  96
  97                 if ((mode & P9_DMSETVTX) == P9_DMSETVTX)
  98                         res |= S_ISVTX;
  99         }
 100         return res;
 101 }
 102
 103 /**
 104  * p9mode2unixmode- convert plan9 mode bits to unix mode bits
 105  * @v9ses: v9fs session information
 106  * @stat: p9_wstat from which mode need to be derived
 107  * @rdev: major number, minor number in case of device files.
 108  *
 109  */
 110 static umode_t p9mode2unixmode(struct v9fs_session_info *v9ses,
 111                                struct p9_wstat *stat, dev_t *rdev)
 112 {
 113         int res;
 114         u32 mode = stat->mode;
 115
 116         *rdev = 0;
 117         res = p9mode2perm(v9ses, stat);
 118
 119         if ((mode & P9_DMDIR) == P9_DMDIR)
 120                 res |= S_IFDIR;
 121         else if ((mode & P9_DMSYMLINK) && (v9fs_proto_dotu(v9ses)))
 122                 res |= S_IFLNK;
 123         else if ((mode & P9_DMSOCKET) && (v9fs_proto_dotu(v9ses))
 124                  && (v9ses->nodev == 0))
 125                 res |= S_IFSOCK;
 126         else if ((mode & P9_DMNAMEDPIPE) && (v9fs_proto_dotu(v9ses))
 127                  && (v9ses->nodev == 0))
 128                 res |= S_IFIFO;
 129         else if ((mode & P9_DMDEVICE) && (v9fs_proto_dotu(v9ses))
 130                  && (v9ses->nodev == 0)) {
 131                 char type = 0, ext[32];
 132                 int major = -1, minor = -1;
 133
 134                 strlcpy(ext, stat->extension, sizeof(ext));
 135                 sscanf(ext, "%c %i %i", &type, &major, &minor);
 136                 switch (type) {
 137                 case 'c':
 138                         res |= S_IFCHR;
 139                         break;
 140                 case 'b':
 141                         res |= S_IFBLK;
 142                         break;
 143                 default:
 144                         p9_debug(P9_DEBUG_ERROR, "Unknown special type %c %s\n",
 145                                  type, stat->extension);
 146                 }
 147                 *rdev = MKDEV(major, minor);
 148         } else
 149                 res |= S_IFREG;
 150
 151         return res;
 152 }
 153
 154 /**
 155  * v9fs_uflags2omode- convert posix open flags to plan 9 mode bits
 156  * @uflags: flags to convert
 157  * @extended: if .u extensions are active
 158  */
 159
 160 int v9fs_uflags2omode(int uflags, int extended)
 161 {
 162         int ret;
 163
 164         ret = 0;
 165         switch (uflags&3) {
 166         default:
 167         case O_RDONLY:
 168                 ret = P9_OREAD;
 169                 break;
 170
 171         case O_WRONLY:
 172                 ret = P9_OWRITE;
 173                 break;
 174
 175         case O_RDWR:
 176                 ret = P9_ORDWR;
 177                 break;
 178         }
 179
 180         if (extended) {
 181                 if (uflags & O_EXCL)
 182                         ret |= P9_OEXCL;
 183
 184                 if (uflags & O_APPEND)
 185                         ret |= P9_OAPPEND;
 186         }
 187
 188         return ret;
 189 }
 190
 191 /**
 192  * v9fs_blank_wstat - helper function to setup a 9P stat structure
 193  * @wstat: structure to initialize
 194  *
 195  */
 196
 197 void
 198 v9fs_blank_wstat(struct p9_wstat *wstat)
 199 {
 200         wstat->type = ~0;
 201         wstat->dev = ~0;
 202         wstat->qid.type = ~0;
 203         wstat->qid.version = ~0;
 204         *((long long *)&wstat->qid.path) = ~0;
 205         wstat->mode = ~0;
 206         wstat->atime = ~0;
 207         wstat->mtime = ~0;
 208         wstat->length = ~0;
 209         wstat->name = NULL;
 210         wstat->uid = NULL;
 211         wstat->gid = NULL;
 212         wstat->muid = NULL;
 213         wstat->n_uid = INVALID_UID;
 214         wstat->n_gid = INVALID_GID;
 215         wstat->n_muid = INVALID_UID;
 216         wstat->extension = NULL;
 217 }
 218
 219 /**
 220  * v9fs_alloc_inode - helper function to allocate an inode
 221  *
 222  */
 223 struct inode *v9fs_alloc_inode(struct super_block *sb)
 224 {
 225         struct v9fs_inode *v9inode;
 226         v9inode = kmem_cache_alloc(v9fs_inode_cache, GFP_KERNEL);
 227         if (!v9inode)
 228                 return NULL;
 229 #ifdef CONFIG_9P_FSCACHE
 230         v9inode->fscache = NULL;
 231         mutex_init(&v9inode->fscache_lock);
 232 #endif
 233         v9inode->writeback_fid = NULL;
 234         v9inode->cache_validity = 0;
 235         mutex_init(&v9inode->v_mutex);
 236         return &v9inode->vfs_inode;
 237 }
 238
 239 /**
 240  * v9fs_free_inode - destroy an inode
 241  *
 242  */
 243
 244 void v9fs_free_inode(struct inode *inode)
 245 {
 246         kmem_cache_free(v9fs_inode_cache, V9FS_I(inode));
 247 }
 248
 249 int v9fs_init_inode(struct v9fs_session_info *v9ses,
 250                     struct inode *inode, umode_t mode, dev_t rdev)
 251 {
 252         int err = 0;
 253
 254         inode_init_owner(inode, NULL, mode);
 255         inode->i_blocks = 0;
 256         inode->i_rdev = rdev;
 257         inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
 258         inode->i_mapping->a_ops = &v9fs_addr_operations;
 259         inode->i_private = NULL;
 260
 261         switch (mode & S_IFMT) {
 262         case S_IFIFO:
 263         case S_IFBLK:
 264         case S_IFCHR:
 265         case S_IFSOCK:
 266                 if (v9fs_proto_dotl(v9ses)) {
 267                         inode->i_op = &v9fs_file_inode_operations_dotl;
 268                 } else if (v9fs_proto_dotu(v9ses)) {
 269                         inode->i_op = &v9fs_file_inode_operations;
 270                 } else {
 271                         p9_debug(P9_DEBUG_ERROR,
 272                                  "special files without extended mode\n");
 273                         err = -EINVAL;
 274                         goto error;
 275                 }
 276                 init_special_inode(inode, inode->i_mode, inode->i_rdev);
 277                 break;
 278         case S_IFREG:
 279                 if (v9fs_proto_dotl(v9ses)) {
 280                         inode->i_op = &v9fs_file_inode_operations_dotl;
 281                         if (v9ses->cache == CACHE_LOOSE ||
 282                             v9ses->cache == CACHE_FSCACHE)
 283                                 inode->i_fop =
 284                                         &v9fs_cached_file_operations_dotl;
 285                         else if (v9ses->cache == CACHE_MMAP)
 286                                 inode->i_fop = &v9fs_mmap_file_operations_dotl;
 287                         else
 288                                 inode->i_fop = &v9fs_file_operations_dotl;
 289                 } else {
 290                         inode->i_op = &v9fs_file_inode_operations;
 291                         if (v9ses->cache == CACHE_LOOSE ||
 292                             v9ses->cache == CACHE_FSCACHE)
 293                                 inode->i_fop =
 294                                         &v9fs_cached_file_operations;
 295                         else if (v9ses->cache == CACHE_MMAP)
 296                                 inode->i_fop = &v9fs_mmap_file_operations;
 297                         else
 298                                 inode->i_fop = &v9fs_file_operations;
 299                 }
 300
 301                 break;
 302         case S_IFLNK:
 303                 if (!v9fs_proto_dotu(v9ses) && !v9fs_proto_dotl(v9ses)) {
 304                         p9_debug(P9_DEBUG_ERROR,
 305                                  "extended modes used with legacy protocol\n");
 306                         err = -EINVAL;
 307                         goto error;
 308                 }
 309
 310                 if (v9fs_proto_dotl(v9ses))
 311                         inode->i_op = &v9fs_symlink_inode_operations_dotl;
 312                 else
 313                         inode->i_op = &v9fs_symlink_inode_operations;
 314
 315                 break;
 316         case S_IFDIR:
 317                 inc_nlink(inode);
 318                 if (v9fs_proto_dotl(v9ses))
 319                         inode->i_op = &v9fs_dir_inode_operations_dotl;
 320                 else if (v9fs_proto_dotu(v9ses))
 321                         inode->i_op = &v9fs_dir_inode_operations_dotu;
 322                 else
 323                         inode->i_op = &v9fs_dir_inode_operations;
 324
 325                 if (v9fs_proto_dotl(v9ses))
 326                         inode->i_fop = &v9fs_dir_operations_dotl;
 327                 else
 328                         inode->i_fop = &v9fs_dir_operations;
 329
 330                 break;
 331         default:
 332                 p9_debug(P9_DEBUG_ERROR, "BAD mode 0x%hx S_IFMT 0x%x\n",
 333                          mode, mode & S_IFMT);
 334                 err = -EINVAL;
 335                 goto error;
 336         }
 337 error:
 338         return err;
 339
 340 }
 341
 342 /**
 343  * v9fs_get_inode - helper function to setup an inode
 344  * @sb: superblock
 345  * @mode: mode to setup inode with
 346  *
 347  */
 348
 349 struct inode *v9fs_get_inode(struct super_block *sb, umode_t mode, dev_t rdev)
 350 {
 351         int err;
 352         struct inode *inode;
 353         struct v9fs_session_info *v9ses = sb->s_fs_info;
 354
 355         p9_debug(P9_DEBUG_VFS, "super block: %p mode: %ho\n", sb, mode);
 356
 357         inode = new_inode(sb);
 358         if (!inode) {
 359                 pr_warn("%s (%d): Problem allocating inode\n",
 360                         __func__, task_pid_nr(current));
 361                 return ERR_PTR(-ENOMEM);
 362         }
 363         err = v9fs_init_inode(v9ses, inode, mode, rdev);
 364         if (err) {
 365                 iput(inode);
 366                 return ERR_PTR(err);
 367         }
 368         return inode;
 369 }
 370
 371 /**
 372  * v9fs_clear_inode - release an inode
 373  * @inode: inode to release
 374  *
 375  */
 376 void v9fs_evict_inode(struct inode *inode)
 377 {
 378         struct v9fs_inode *v9inode = V9FS_I(inode);
 379
 380         truncate_inode_pages_final(&inode->i_data);
 381         clear_inode(inode);
 382         filemap_fdatawrite(&inode->i_data);
 383
 384         v9fs_cache_inode_put_cookie(inode);
 385         /* clunk the fid stashed in writeback_fid */
 386         if (v9inode->writeback_fid) {
 387                 p9_client_clunk(v9inode->writeback_fid);
 388                 v9inode->writeback_fid = NULL;
 389         }
 390 }
 391
 392 static int v9fs_test_inode(struct inode *inode, void *data)
 393 {
 394         int umode;
 395         dev_t rdev;
 396         struct v9fs_inode *v9inode = V9FS_I(inode);
 397         struct p9_wstat *st = (struct p9_wstat *)data;
 398         struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
 399
 400         umode = p9mode2unixmode(v9ses, st, &rdev);
 401         /* don't match inode of different type */
 402         if ((inode->i_mode & S_IFMT) != (umode & S_IFMT))
 403                 return 0;
 404
 405         /* compare qid details */
 406         if (memcmp(&v9inode->qid.version,
 407                    &st->qid.version, sizeof(v9inode->qid.version)))
 408                 return 0;
 409
 410         if (v9inode->qid.type != st->qid.type)
 411                 return 0;
 412
 413         if (v9inode->qid.path != st->qid.path)
 414                 return 0;
 415         return 1;
 416 }
 417
 418 static int v9fs_test_new_inode(struct inode *inode, void *data)
 419 {
 420         return 0;
 421 }
 422
 423 static int v9fs_set_inode(struct inode *inode,  void *data)
 424 {
 425         struct v9fs_inode *v9inode = V9FS_I(inode);
 426         struct p9_wstat *st = (struct p9_wstat *)data;
 427
 428         memcpy(&v9inode->qid, &st->qid, sizeof(st->qid));
 429         return 0;
 430 }
 431
 432 static struct inode *v9fs_qid_iget(struct super_block *sb,
 433                                    struct p9_qid *qid,
 434                                    struct p9_wstat *st,
 435                                    int new)
 436 {
 437         dev_t rdev;
 438         int retval;
 439         umode_t umode;
 440         unsigned long i_ino;
 441         struct inode *inode;
 442         struct v9fs_session_info *v9ses = sb->s_fs_info;
 443         int (*test)(struct inode *, void *);
 444
 445         if (new)
 446                 test = v9fs_test_new_inode;
 447         else
 448                 test = v9fs_test_inode;
 449
 450         i_ino = v9fs_qid2ino(qid);
 451         inode = iget5_locked(sb, i_ino, test, v9fs_set_inode, st);
 452         if (!inode)
 453                 return ERR_PTR(-ENOMEM);
 454         if (!(inode->i_state & I_NEW))
 455                 return inode;
 456         /*
 457          * initialize the inode with the stat info
 458          * FIXME!! we may need support for stale inodes
 459          * later.
 460          */
 461         inode->i_ino = i_ino;
 462         umode = p9mode2unixmode(v9ses, st, &rdev);
 463         retval = v9fs_init_inode(v9ses, inode, umode, rdev);
 464         if (retval)
 465                 goto error;
 466
 467         v9fs_stat2inode(st, inode, sb, 0);
 468         v9fs_cache_inode_get_cookie(inode);
 469         unlock_new_inode(inode);
 470         return inode;
 471 error:
 472         iget_failed(inode);
 473         return ERR_PTR(retval);
 474
 475 }
 476
 477 struct inode *
 478 v9fs_inode_from_fid(struct v9fs_session_info *v9ses, struct p9_fid *fid,
 479                     struct super_block *sb, int new)
 480 {
 481         struct p9_wstat *st;
 482         struct inode *inode = NULL;
 483
 484         st = p9_client_stat(fid);
 485         if (IS_ERR(st))
 486                 return ERR_CAST(st);
 487
 488         inode = v9fs_qid_iget(sb, &st->qid, st, new);
 489         p9stat_free(st);
 490         kfree(st);
 491         return inode;
 492 }
 493
 494 /**
 495  * v9fs_at_to_dotl_flags- convert Linux specific AT flags to
 496  * plan 9 AT flag.
 497  * @flags: flags to convert
 498  */
 499 static int v9fs_at_to_dotl_flags(int flags)
 500 {
 501         int rflags = 0;
 502         if (flags & AT_REMOVEDIR)
 503                 rflags |= P9_DOTL_AT_REMOVEDIR;
 504         return rflags;
 505 }
 506
 507 /**
 508  * v9fs_dec_count - helper functon to drop i_nlink.
 509  *
 510  * If a directory had nlink <= 2 (including . and ..), then we should not drop
 511  * the link count, which indicates the underlying exported fs doesn't maintain
 512  * nlink accurately. e.g.
 513  * - overlayfs sets nlink to 1 for merged dir
 514  * - ext4 (with dir_nlink feature enabled) sets nlink to 1 if a dir has more
 515  *   than EXT4_LINK_MAX (65000) links.
 516  *
 517  * @inode: inode whose nlink is being dropped
 518  */
 519 static void v9fs_dec_count(struct inode *inode)
 520 {
 521         if (!S_ISDIR(inode->i_mode) || inode->i_nlink > 2)
 522                 drop_nlink(inode);
 523 }
 524
 525 /**
 526  * v9fs_remove - helper function to remove files and directories
 527  * @dir: directory inode that is being deleted
 528  * @dentry:  dentry that is being deleted
 529  * @flags: removing a directory
 530  *
 531  */
 532
 533 static int v9fs_remove(struct inode *dir, struct dentry *dentry, int flags)
 534 {
 535         struct inode *inode;
 536         int retval = -EOPNOTSUPP;
 537         struct p9_fid *v9fid, *dfid;
 538         struct v9fs_session_info *v9ses;
 539
 540         p9_debug(P9_DEBUG_VFS, "inode: %p dentry: %p rmdir: %x\n",
 541                  dir, dentry, flags);
 542
 543         v9ses = v9fs_inode2v9ses(dir);
 544         inode = d_inode(dentry);
 545         dfid = v9fs_parent_fid(dentry);
 546         if (IS_ERR(dfid)) {
 547                 retval = PTR_ERR(dfid);
 548                 p9_debug(P9_DEBUG_VFS, "fid lookup failed %d\n", retval);
 549                 return retval;
 550         }
 551         if (v9fs_proto_dotl(v9ses))
 552                 retval = p9_client_unlinkat(dfid, dentry->d_name.name,
 553                                             v9fs_at_to_dotl_flags(flags));
 554         p9_client_clunk(dfid);
 555         if (retval == -EOPNOTSUPP) {
 556                 /* Try the one based on path */
 557                 v9fid = v9fs_fid_clone(dentry);
 558                 if (IS_ERR(v9fid))
 559                         return PTR_ERR(v9fid);
 560                 retval = p9_client_remove(v9fid);
 561         }
 562         if (!retval) {
 563                 /*
 564                  * directories on unlink should have zero
 565                  * link count
 566                  */
 567                 if (flags & AT_REMOVEDIR) {
 568                         clear_nlink(inode);
 569                         v9fs_dec_count(dir);
 570                 } else
 571                         v9fs_dec_count(inode);
 572
 573                 v9fs_invalidate_inode_attr(inode);
 574                 v9fs_invalidate_inode_attr(dir);
 575
 576                 /* invalidate all fids associated with dentry */
 577                 /* NOTE: This will not include open fids */
 578                 dentry->d_op->d_release(dentry);
 579         }
 580         return retval;
 581 }
 582
 583 /**
 584  * v9fs_create - Create a file
 585  * @v9ses: session information
 586  * @dir: directory that dentry is being created in
 587  * @dentry:  dentry that is being created
 588  * @extension: 9p2000.u extension string to support devices, etc.
 589  * @perm: create permissions
 590  * @mode: open mode
 591  *
 592  */
 593 static struct p9_fid *
 594 v9fs_create(struct v9fs_session_info *v9ses, struct inode *dir,
 595                 struct dentry *dentry, char *extension, u32 perm, u8 mode)
 596 {
 597         int err;
 598         const unsigned char *name;
 599         struct p9_fid *dfid, *ofid = NULL, *fid = NULL;
 600         struct inode *inode;
 601
 602         p9_debug(P9_DEBUG_VFS, "name %pd\n", dentry);
 603
 604         err = 0;
 605         name = dentry->d_name.name;
 606         dfid = v9fs_parent_fid(dentry);
 607         if (IS_ERR(dfid)) {
 608                 err = PTR_ERR(dfid);
 609                 p9_debug(P9_DEBUG_VFS, "fid lookup failed %d\n", err);
 610                 return ERR_PTR(err);
 611         }
 612
 613         /* clone a fid to use for creation */
 614         ofid = clone_fid(dfid);
 615         if (IS_ERR(ofid)) {
 616                 err = PTR_ERR(ofid);
 617                 p9_debug(P9_DEBUG_VFS, "p9_client_walk failed %d\n", err);
 618                 p9_client_clunk(dfid);
 619                 return ERR_PTR(err);
 620         }
 621
 622         err = p9_client_fcreate(ofid, name, perm, mode, extension);
 623         if (err < 0) {
 624                 p9_debug(P9_DEBUG_VFS, "p9_client_fcreate failed %d\n", err);
 625                 p9_client_clunk(dfid);
 626                 goto error;
 627         }
 628
 629         if (!(perm & P9_DMLINK)) {
 630                 /* now walk from the parent so we can get unopened fid */
 631                 fid = p9_client_walk(dfid, 1, &name, 1);
 632                 if (IS_ERR(fid)) {
 633                         err = PTR_ERR(fid);
 634                         p9_debug(P9_DEBUG_VFS,
 635                                    "p9_client_walk failed %d\n", err);
 636                         fid = NULL;
 637                         p9_client_clunk(dfid);
 638                         goto error;
 639                 }
 640                 /*
 641                  * instantiate inode and assign the unopened fid to the dentry
 642                  */
 643                 inode = v9fs_get_new_inode_from_fid(v9ses, fid, dir->i_sb);
 644                 if (IS_ERR(inode)) {
 645                         err = PTR_ERR(inode);
 646                         p9_debug(P9_DEBUG_VFS,
 647                                    "inode creation failed %d\n", err);
 648                         p9_client_clunk(dfid);
 649                         goto error;
 650                 }
 651                 v9fs_fid_add(dentry, fid);
 652                 d_instantiate(dentry, inode);
 653         }
 654         p9_client_clunk(dfid);
 655         return ofid;
 656 error:
 657         if (ofid)
 658                 p9_client_clunk(ofid);
 659
 660         if (fid)
 661                 p9_client_clunk(fid);
 662
 663         return ERR_PTR(err);
 664 }
 665
 666 /**
 667  * v9fs_vfs_create - VFS hook to create a regular file
 668  *
 669  * open(.., O_CREAT) is handled in v9fs_vfs_atomic_open().  This is only called
 670  * for mknod(2).
 671  *
 672  * @dir: directory inode that is being created
 673  * @dentry:  dentry that is being deleted
 674  * @mode: create permissions
 675  *
 676  */
 677
 678 static int
 679 v9fs_vfs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
 680                 bool excl)
 681 {
 682         struct v9fs_session_info *v9ses = v9fs_inode2v9ses(dir);
 683         u32 perm = unixmode2p9mode(v9ses, mode);
 684         struct p9_fid *fid;
 685
 686         /* P9_OEXCL? */
 687         fid = v9fs_create(v9ses, dir, dentry, NULL, perm, P9_ORDWR);
 688         if (IS_ERR(fid))
 689                 return PTR_ERR(fid);
 690
 691         v9fs_invalidate_inode_attr(dir);
 692         p9_client_clunk(fid);
 693
 694         return 0;
 695 }
 696
 697 /**
 698  * v9fs_vfs_mkdir - VFS mkdir hook to create a directory
 699  * @dir:  inode that is being unlinked
 700  * @dentry: dentry that is being unlinked
 701  * @mode: mode for new directory
 702  *
 703  */
 704
 705 static int v9fs_vfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 706 {
 707         int err;
 708         u32 perm;
 709         struct p9_fid *fid;
 710         struct v9fs_session_info *v9ses;
 711
 712         p9_debug(P9_DEBUG_VFS, "name %pd\n", dentry);
 713         err = 0;
 714         v9ses = v9fs_inode2v9ses(dir);
 715         perm = unixmode2p9mode(v9ses, mode | S_IFDIR);
 716         fid = v9fs_create(v9ses, dir, dentry, NULL, perm, P9_OREAD);
 717         if (IS_ERR(fid)) {
 718                 err = PTR_ERR(fid);
 719                 fid = NULL;
 720         } else {
 721                 inc_nlink(dir);
 722                 v9fs_invalidate_inode_attr(dir);
 723         }
 724
 725         if (fid)
 726                 p9_client_clunk(fid);
 727
 728         return err;
 729 }
 730
 731 /**
 732  * v9fs_vfs_lookup - VFS lookup hook to "walk" to a new inode
 733  * @dir:  inode that is being walked from
 734  * @dentry: dentry that is being walked to?
 735  * @flags: lookup flags (unused)
 736  *
 737  */
 738
 739 struct dentry *v9fs_vfs_lookup(struct inode *dir, struct dentry *dentry,
 740                                       unsigned int flags)
 741 {
 742         struct dentry *res;
 743         struct v9fs_session_info *v9ses;
 744         struct p9_fid *dfid, *fid;
 745         struct inode *inode;
 746         const unsigned char *name;
 747
 748         p9_debug(P9_DEBUG_VFS, "dir: %p dentry: (%pd) %p flags: %x\n",
 749                  dir, dentry, dentry, flags);
 750
 751         if (dentry->d_name.len > NAME_MAX)
 752                 return ERR_PTR(-ENAMETOOLONG);
 753
 754         v9ses = v9fs_inode2v9ses(dir);
 755         /* We can walk d_parent because we hold the dir->i_mutex */
 756         dfid = v9fs_parent_fid(dentry);
 757         if (IS_ERR(dfid))
 758                 return ERR_CAST(dfid);
 759
 760         /*
 761          * Make sure we don't use a wrong inode due to parallel
 762          * unlink. For cached mode create calls request for new
 763          * inode. But with cache disabled, lookup should do this.
 764          */
 765         name = dentry->d_name.name;
 766         fid = p9_client_walk(dfid, 1, &name, 1);
 767         p9_client_clunk(dfid);
 768         if (fid == ERR_PTR(-ENOENT))
 769                 inode = NULL;
 770         else if (IS_ERR(fid))
 771                 inode = ERR_CAST(fid);
 772         else if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
 773                 inode = v9fs_get_inode_from_fid(v9ses, fid, dir->i_sb);
 774         else
 775                 inode = v9fs_get_new_inode_from_fid(v9ses, fid, dir->i_sb);
 776         /*
 777          * If we had a rename on the server and a parallel lookup
 778          * for the new name, then make sure we instantiate with
 779          * the new name. ie look up for a/b, while on server somebody
 780          * moved b under k and client parallely did a lookup for
 781          * k/b.
 782          */
 783         res = d_splice_alias(inode, dentry);
 784         if (!IS_ERR(fid)) {
 785                 if (!res)
 786                         v9fs_fid_add(dentry, fid);
 787                 else if (!IS_ERR(res))
 788                         v9fs_fid_add(res, fid);
 789                 else
 790                         p9_client_clunk(fid);
 791         }
 792         return res;
 793 }
 794
 795 static int
 796 v9fs_vfs_atomic_open(struct inode *dir, struct dentry *dentry,
 797                      struct file *file, unsigned flags, umode_t mode)
 798 {
 799         int err;
 800         u32 perm;
 801         struct v9fs_inode *v9inode;
 802         struct v9fs_session_info *v9ses;
 803         struct p9_fid *fid, *inode_fid;
 804         struct dentry *res = NULL;
 805         struct inode *inode;
 806
 807         if (d_in_lookup(dentry)) {
 808                 res = v9fs_vfs_lookup(dir, dentry, 0);
 809                 if (IS_ERR(res))
 810                         return PTR_ERR(res);
 811
 812                 if (res)
 813                         dentry = res;
 814         }
 815
 816         /* Only creates */
 817         if (!(flags & O_CREAT) || d_really_is_positive(dentry))
 818                 return finish_no_open(file, res);
 819
 820         err = 0;
 821
 822         v9ses = v9fs_inode2v9ses(dir);
 823         perm = unixmode2p9mode(v9ses, mode);
 824         fid = v9fs_create(v9ses, dir, dentry, NULL, perm,
 825                                 v9fs_uflags2omode(flags,
 826                                                 v9fs_proto_dotu(v9ses)));
 827         if (IS_ERR(fid)) {
 828                 err = PTR_ERR(fid);
 829                 fid = NULL;
 830                 goto error;
 831         }
 832
 833         v9fs_invalidate_inode_attr(dir);
 834         inode = d_inode(dentry);
 835         v9inode = V9FS_I(inode);
 836         mutex_lock(&v9inode->v_mutex);
 837         if ((v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE) &&
 838             !v9inode->writeback_fid &&
 839             ((flags & O_ACCMODE) != O_RDONLY)) {
 840                 /*
 841                  * clone a fid and add it to writeback_fid
 842                  * we do it during open time instead of
 843                  * page dirty time via write_begin/page_mkwrite
 844                  * because we want write after unlink usecase
 845                  * to work.
 846                  */
 847                 inode_fid = v9fs_writeback_fid(dentry);
 848                 if (IS_ERR(inode_fid)) {
 849                         err = PTR_ERR(inode_fid);
 850                         mutex_unlock(&v9inode->v_mutex);
 851                         goto error;
 852                 }
 853                 v9inode->writeback_fid = (void *) inode_fid;
 854         }
 855         mutex_unlock(&v9inode->v_mutex);
 856         err = finish_open(file, dentry, generic_file_open);
 857         if (err)
 858                 goto error;
 859
 860         file->private_data = fid;
 861         if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
 862                 v9fs_cache_inode_set_cookie(d_inode(dentry), file);
 863         v9fs_open_fid_add(inode, fid);
 864
 865         file->f_mode |= FMODE_CREATED;
 866 out:
 867         dput(res);
 868         return err;
 869
 870 error:
 871         if (fid)
 872                 p9_client_clunk(fid);
 873         goto out;
 874 }
 875
 876 /**
 877  * v9fs_vfs_unlink - VFS unlink hook to delete an inode
 878  * @i:  inode that is being unlinked
 879  * @d: dentry that is being unlinked
 880  *
 881  */
 882
 883 int v9fs_vfs_unlink(struct inode *i, struct dentry *d)
 884 {
 885         return v9fs_remove(i, d, 0);
 886 }
 887
 888 /**
 889  * v9fs_vfs_rmdir - VFS unlink hook to delete a directory
 890  * @i:  inode that is being unlinked
 891  * @d: dentry that is being unlinked
 892  *
 893  */
 894
 895 int v9fs_vfs_rmdir(struct inode *i, struct dentry *d)
 896 {
 897         return v9fs_remove(i, d, AT_REMOVEDIR);
 898 }
 899
 900 /**
 901  * v9fs_vfs_rename - VFS hook to rename an inode
 902  * @old_dir:  old dir inode
 903  * @old_dentry: old dentry
 904  * @new_dir: new dir inode
 905  * @new_dentry: new dentry
 906  *
 907  */
 908
 909 int
 910 v9fs_vfs_rename(struct inode *old_dir, struct dentry *old_dentry,
 911                 struct inode *new_dir, struct dentry *new_dentry,
 912                 unsigned int flags)
 913 {
 914         int retval;
 915         struct inode *old_inode;
 916         struct inode *new_inode;
 917         struct v9fs_session_info *v9ses;
 918         struct p9_fid *oldfid, *dfid;
 919         struct p9_fid *olddirfid;
 920         struct p9_fid *newdirfid;
 921         struct p9_wstat wstat;
 922
 923         if (flags)
 924                 return -EINVAL;
 925
 926         p9_debug(P9_DEBUG_VFS, "\n");
 927         retval = 0;
 928         old_inode = d_inode(old_dentry);
 929         new_inode = d_inode(new_dentry);
 930         v9ses = v9fs_inode2v9ses(old_inode);
 931         oldfid = v9fs_fid_lookup(old_dentry);
 932         if (IS_ERR(oldfid))
 933                 return PTR_ERR(oldfid);
 934
 935         dfid = v9fs_parent_fid(old_dentry);
 936         olddirfid = clone_fid(dfid);
 937         if (dfid && !IS_ERR(dfid))
 938                 p9_client_clunk(dfid);
 939
 940         if (IS_ERR(olddirfid)) {
 941                 retval = PTR_ERR(olddirfid);
 942                 goto done;
 943         }
 944
 945         dfid = v9fs_parent_fid(new_dentry);
 946         newdirfid = clone_fid(dfid);
 947         p9_client_clunk(dfid);
 948
 949         if (IS_ERR(newdirfid)) {
 950                 retval = PTR_ERR(newdirfid);
 951                 goto clunk_olddir;
 952         }
 953
 954         down_write(&v9ses->rename_sem);
 955         if (v9fs_proto_dotl(v9ses)) {
 956                 retval = p9_client_renameat(olddirfid, old_dentry->d_name.name,
 957                                             newdirfid, new_dentry->d_name.name);
 958                 if (retval == -EOPNOTSUPP)
 959                         retval = p9_client_rename(oldfid, newdirfid,
 960                                                   new_dentry->d_name.name);
 961                 if (retval != -EOPNOTSUPP)
 962                         goto clunk_newdir;
 963         }
 964         if (old_dentry->d_parent != new_dentry->d_parent) {
 965                 /*
 966                  * 9P .u can only handle file rename in the same directory
 967                  */
 968
 969                 p9_debug(P9_DEBUG_ERROR, "old dir and new dir are different\n");
 970                 retval = -EXDEV;
 971                 goto clunk_newdir;
 972         }
 973         v9fs_blank_wstat(&wstat);
 974         wstat.muid = v9ses->uname;
 975         wstat.name = new_dentry->d_name.name;
 976         retval = p9_client_wstat(oldfid, &wstat);
 977
 978 clunk_newdir:
 979         if (!retval) {
 980                 if (new_inode) {
 981                         if (S_ISDIR(new_inode->i_mode))
 982                                 clear_nlink(new_inode);
 983                         else
 984                                 v9fs_dec_count(new_inode);
 985                 }
 986                 if (S_ISDIR(old_inode->i_mode)) {
 987                         if (!new_inode)
 988                                 inc_nlink(new_dir);
 989                         v9fs_dec_count(old_dir);
 990                 }
 991                 v9fs_invalidate_inode_attr(old_inode);
 992                 v9fs_invalidate_inode_attr(old_dir);
 993                 v9fs_invalidate_inode_attr(new_dir);
 994
 995                 /* successful rename */
 996                 d_move(old_dentry, new_dentry);
 997         }
 998         up_write(&v9ses->rename_sem);
 999         p9_client_clunk(newdirfid);
1000
1001 clunk_olddir:
1002         p9_client_clunk(olddirfid);
1003
1004 done:
1005         p9_client_clunk(oldfid);
1006         return retval;
1007 }
1008
1009 /**
1010  * v9fs_vfs_getattr - retrieve file metadata
1011  * @path: Object to query
1012  * @stat: metadata structure to populate
1013  * @request_mask: Mask of STATX_xxx flags indicating the caller's interests
1014  * @flags: AT_STATX_xxx setting
1015  *
1016  */
1017
1018 static int
1019 v9fs_vfs_getattr(const struct path *path, struct kstat *stat,
1020                  u32 request_mask, unsigned int flags)
1021 {
1022         struct dentry *dentry = path->dentry;
1023         struct v9fs_session_info *v9ses;
1024         struct p9_fid *fid;
1025         struct p9_wstat *st;
1026
1027         p9_debug(P9_DEBUG_VFS, "dentry: %p\n", dentry);
1028         v9ses = v9fs_dentry2v9ses(dentry);
1029         if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE) {
1030                 generic_fillattr(d_inode(dentry), stat);
1031                 return 0;
1032         }
1033         fid = v9fs_fid_lookup(dentry);
1034         if (IS_ERR(fid))
1035                 return PTR_ERR(fid);
1036
1037         st = p9_client_stat(fid);
1038         p9_client_clunk(fid);
1039         if (IS_ERR(st))
1040                 return PTR_ERR(st);
1041
1042         v9fs_stat2inode(st, d_inode(dentry), dentry->d_sb, 0);
1043         generic_fillattr(d_inode(dentry), stat);
1044
1045         p9stat_free(st);
1046         kfree(st);
1047         return 0;
1048 }
1049
1050 /**
1051  * v9fs_vfs_setattr - set file metadata
1052  * @dentry: file whose metadata to set
1053  * @iattr: metadata assignment structure
1054  *
1055  */
1056
1057 static int v9fs_vfs_setattr(struct dentry *dentry, struct iattr *iattr)
1058 {
1059         int retval, use_dentry = 0;
1060         struct v9fs_session_info *v9ses;
1061         struct p9_fid *fid = NULL;
1062         struct p9_wstat wstat;
1063
1064         p9_debug(P9_DEBUG_VFS, "\n");
1065         retval = setattr_prepare(dentry, iattr);
1066         if (retval)
1067                 return retval;
1068
1069         retval = -EPERM;
1070         v9ses = v9fs_dentry2v9ses(dentry);
1071         if (iattr->ia_valid & ATTR_FILE) {
1072                 fid = iattr->ia_file->private_data;
1073                 WARN_ON(!fid);
1074         }
1075         if (!fid) {
1076                 fid = v9fs_fid_lookup(dentry);
1077                 use_dentry = 1;
1078         }
1079         if(IS_ERR(fid))
1080                 return PTR_ERR(fid);
1081
1082         v9fs_blank_wstat(&wstat);
1083         if (iattr->ia_valid & ATTR_MODE)
1084                 wstat.mode = unixmode2p9mode(v9ses, iattr->ia_mode);
1085
1086         if (iattr->ia_valid & ATTR_MTIME)
1087                 wstat.mtime = iattr->ia_mtime.tv_sec;
1088
1089         if (iattr->ia_valid & ATTR_ATIME)
1090                 wstat.atime = iattr->ia_atime.tv_sec;
1091
1092         if (iattr->ia_valid & ATTR_SIZE)
1093                 wstat.length = iattr->ia_size;
1094
1095         if (v9fs_proto_dotu(v9ses)) {
1096                 if (iattr->ia_valid & ATTR_UID)
1097                         wstat.n_uid = iattr->ia_uid;
1098
1099                 if (iattr->ia_valid & ATTR_GID)
1100                         wstat.n_gid = iattr->ia_gid;
1101         }
1102
1103         /* Write all dirty data */
1104         if (d_is_reg(dentry))
1105                 filemap_write_and_wait(d_inode(dentry)->i_mapping);
1106
1107         retval = p9_client_wstat(fid, &wstat);
1108
1109         if (use_dentry)
1110                 p9_client_clunk(fid);
1111
1112         if (retval < 0)
1113                 return retval;
1114
1115         if ((iattr->ia_valid & ATTR_SIZE) &&
1116             iattr->ia_size != i_size_read(d_inode(dentry)))
1117                 truncate_setsize(d_inode(dentry), iattr->ia_size);
1118
1119         v9fs_invalidate_inode_attr(d_inode(dentry));
1120
1121         setattr_copy(d_inode(dentry), iattr);
1122         mark_inode_dirty(d_inode(dentry));
1123         return 0;
1124 }
1125
1126 /**
1127  * v9fs_stat2inode - populate an inode structure with mistat info
1128  * @stat: Plan 9 metadata (mistat) structure
1129  * @inode: inode to populate
1130  * @sb: superblock of filesystem
1131  * @flags: control flags (e.g. V9FS_STAT2INODE_KEEP_ISIZE)
1132  *
1133  */
1134
1135 void
1136 v9fs_stat2inode(struct p9_wstat *stat, struct inode *inode,
1137                  struct super_block *sb, unsigned int flags)
1138 {
1139         umode_t mode;
1140         char ext[32];
1141         char tag_name[14];
1142         unsigned int i_nlink;
1143         struct v9fs_session_info *v9ses = sb->s_fs_info;
1144         struct v9fs_inode *v9inode = V9FS_I(inode);
1145
1146         set_nlink(inode, 1);
1147
1148         inode->i_atime.tv_sec = stat->atime;
1149         inode->i_mtime.tv_sec = stat->mtime;
1150         inode->i_ctime.tv_sec = stat->mtime;
1151
1152         inode->i_uid = v9ses->dfltuid;
1153         inode->i_gid = v9ses->dfltgid;
1154
1155         if (v9fs_proto_dotu(v9ses)) {
1156                 inode->i_uid = stat->n_uid;
1157                 inode->i_gid = stat->n_gid;
1158         }
1159         if ((S_ISREG(inode->i_mode)) || (S_ISDIR(inode->i_mode))) {
1160                 if (v9fs_proto_dotu(v9ses) && (stat->extension[0] != '\0')) {
1161                         /*
1162                          * Hadlink support got added later to
1163                          * to the .u extension. So there can be
1164                          * server out there that doesn't support
1165                          * this even with .u extension. So check
1166                          * for non NULL stat->extension
1167                          */
1168                         strlcpy(ext, stat->extension, sizeof(ext));
1169                         /* HARDLINKCOUNT %u */
1170                         sscanf(ext, "%13s %u", tag_name, &i_nlink);
1171                         if (!strncmp(tag_name, "HARDLINKCOUNT", 13))
1172                                 set_nlink(inode, i_nlink);
1173                 }
1174         }
1175         mode = p9mode2perm(v9ses, stat);
1176         mode |= inode->i_mode & ~S_IALLUGO;
1177         inode->i_mode = mode;
1178
1179         if (!(flags & V9FS_STAT2INODE_KEEP_ISIZE))
1180                 v9fs_i_size_write(inode, stat->length);
1181         /* not real number of blocks, but 512 byte ones ... */
1182         inode->i_blocks = (stat->length + 512 - 1) >> 9;
1183         v9inode->cache_validity &= ~V9FS_INO_INVALID_ATTR;
1184 }
1185
1186 /**
1187  * v9fs_qid2ino - convert qid into inode number
1188  * @qid: qid to hash
1189  *
1190  * BUG: potential for inode number collisions?
1191  */
1192
1193 ino_t v9fs_qid2ino(struct p9_qid *qid)
1194 {
1195         u64 path = qid->path + 2;
1196         ino_t i = 0;
1197
1198         if (sizeof(ino_t) == sizeof(path))
1199                 memcpy(&i, &path, sizeof(ino_t));
1200         else
1201                 i = (ino_t) (path ^ (path >> 32));
1202
1203         return i;
1204 }
1205
1206 /**
1207  * v9fs_vfs_get_link - follow a symlink path
1208  * @dentry: dentry for symlink
1209  * @inode: inode for symlink
1210  * @done: delayed call for when we are done with the return value
1211  */
1212
1213 static const char *v9fs_vfs_get_link(struct dentry *dentry,
1214                                      struct inode *inode,
1215                                      struct delayed_call *done)
1216 {
1217         struct v9fs_session_info *v9ses;
1218         struct p9_fid *fid;
1219         struct p9_wstat *st;
1220         char *res;
1221
1222         if (!dentry)
1223                 return ERR_PTR(-ECHILD);
1224
1225         v9ses = v9fs_dentry2v9ses(dentry);
1226         fid = v9fs_fid_lookup(dentry);
1227         p9_debug(P9_DEBUG_VFS, "%pd\n", dentry);
1228
1229         if (IS_ERR(fid))
1230                 return ERR_CAST(fid);
1231
1232         if (!v9fs_proto_dotu(v9ses))
1233                 return ERR_PTR(-EBADF);
1234
1235         st = p9_client_stat(fid);
1236         p9_client_clunk(fid);
1237         if (IS_ERR(st))
1238                 return ERR_CAST(st);
1239
1240         if (!(st->mode & P9_DMSYMLINK)) {
1241                 p9stat_free(st);
1242                 kfree(st);
1243                 return ERR_PTR(-EINVAL);
1244         }
1245         res = st->extension;
1246         st->extension = NULL;
1247         if (strlen(res) >= PATH_MAX)
1248                 res[PATH_MAX - 1] = '\0';
1249
1250         p9stat_free(st);
1251         kfree(st);
1252         set_delayed_call(done, kfree_link, res);
1253         return res;
1254 }
1255
1256 /**
1257  * v9fs_vfs_mkspecial - create a special file
1258  * @dir: inode to create special file in
1259  * @dentry: dentry to create
1260  * @perm: mode to create special file
1261  * @extension: 9p2000.u format extension string representing special file
1262  *
1263  */
1264
1265 static int v9fs_vfs_mkspecial(struct inode *dir, struct dentry *dentry,
1266         u32 perm, const char *extension)
1267 {
1268         struct p9_fid *fid;
1269         struct v9fs_session_info *v9ses;
1270
1271         v9ses = v9fs_inode2v9ses(dir);
1272         if (!v9fs_proto_dotu(v9ses)) {
1273                 p9_debug(P9_DEBUG_ERROR, "not extended\n");
1274                 return -EPERM;
1275         }
1276
1277         fid = v9fs_create(v9ses, dir, dentry, (char *) extension, perm,
1278                                                                 P9_OREAD);
1279         if (IS_ERR(fid))
1280                 return PTR_ERR(fid);
1281
1282         v9fs_invalidate_inode_attr(dir);
1283         p9_client_clunk(fid);
1284         return 0;
1285 }
1286
1287 /**
1288  * v9fs_vfs_symlink - helper function to create symlinks
1289  * @dir: directory inode containing symlink
1290  * @dentry: dentry for symlink
1291  * @symname: symlink data
1292  *
1293  * See Also: 9P2000.u RFC for more information
1294  *
1295  */
1296
1297 static int
1298 v9fs_vfs_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
1299 {
1300         p9_debug(P9_DEBUG_VFS, " %lu,%pd,%s\n",
1301                  dir->i_ino, dentry, symname);
1302
1303         return v9fs_vfs_mkspecial(dir, dentry, P9_DMSYMLINK, symname);
1304 }
1305
1306 #define U32_MAX_DIGITS 10
1307
1308 /**
1309  * v9fs_vfs_link - create a hardlink
1310  * @old_dentry: dentry for file to link to
1311  * @dir: inode destination for new link
1312  * @dentry: dentry for link
1313  *
1314  */
1315
1316 static int
1317 v9fs_vfs_link(struct dentry *old_dentry, struct inode *dir,
1318               struct dentry *dentry)
1319 {
1320         int retval;
1321         char name[1 + U32_MAX_DIGITS + 2]; /* sign + number + \n + \0 */
1322         struct p9_fid *oldfid;
1323
1324         p9_debug(P9_DEBUG_VFS, " %lu,%pd,%pd\n",
1325                  dir->i_ino, dentry, old_dentry);
1326
1327         oldfid = v9fs_fid_clone(old_dentry);
1328         if (IS_ERR(oldfid))
1329                 return PTR_ERR(oldfid);
1330
1331         sprintf(name, "%d\n", oldfid->fid);
1332         retval = v9fs_vfs_mkspecial(dir, dentry, P9_DMLINK, name);
1333         if (!retval) {
1334                 v9fs_refresh_inode(oldfid, d_inode(old_dentry));
1335                 v9fs_invalidate_inode_attr(dir);
1336         }
1337         p9_client_clunk(oldfid);
1338         return retval;
1339 }
1340
1341 /**
1342  * v9fs_vfs_mknod - create a special file
1343  * @dir: inode destination for new link
1344  * @dentry: dentry for file
1345  * @mode: mode for creation
1346  * @rdev: device associated with special file
1347  *
1348  */
1349
1350 static int
1351 v9fs_vfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t rdev)
1352 {
1353         struct v9fs_session_info *v9ses = v9fs_inode2v9ses(dir);
1354         int retval;
1355         char name[2 + U32_MAX_DIGITS + 1 + U32_MAX_DIGITS + 1];
1356         u32 perm;
1357
1358         p9_debug(P9_DEBUG_VFS, " %lu,%pd mode: %hx MAJOR: %u MINOR: %u\n",
1359                  dir->i_ino, dentry, mode,
1360                  MAJOR(rdev), MINOR(rdev));
1361
1362         /* build extension */
1363         if (S_ISBLK(mode))
1364                 sprintf(name, "b %u %u", MAJOR(rdev), MINOR(rdev));
1365         else if (S_ISCHR(mode))
1366                 sprintf(name, "c %u %u", MAJOR(rdev), MINOR(rdev));
1367         else
1368                 *name = 0;
1369
1370         perm = unixmode2p9mode(v9ses, mode);
1371         retval = v9fs_vfs_mkspecial(dir, dentry, perm, name);
1372
1373         return retval;
1374 }
1375
1376 int v9fs_refresh_inode(struct p9_fid *fid, struct inode *inode)
1377 {
1378         int umode;
1379         dev_t rdev;
1380         struct p9_wstat *st;
1381         struct v9fs_session_info *v9ses;
1382         unsigned int flags;
1383
1384         v9ses = v9fs_inode2v9ses(inode);
1385         st = p9_client_stat(fid);
1386         if (IS_ERR(st))
1387                 return PTR_ERR(st);
1388         /*
1389          * Don't update inode if the file type is different
1390          */
1391         umode = p9mode2unixmode(v9ses, st, &rdev);
1392         if ((inode->i_mode & S_IFMT) != (umode & S_IFMT))
1393                 goto out;
1394
1395         /*
1396          * We don't want to refresh inode->i_size,
1397          * because we may have cached data
1398          */
1399         flags = (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE) ?
1400                 V9FS_STAT2INODE_KEEP_ISIZE : 0;
1401         v9fs_stat2inode(st, inode, inode->i_sb, flags);
1402 out:
1403         p9stat_free(st);
1404         kfree(st);
1405         return 0;
1406 }
1407
1408 static const struct inode_operations v9fs_dir_inode_operations_dotu = {
1409         .create = v9fs_vfs_create,
1410         .lookup = v9fs_vfs_lookup,
1411         .atomic_open = v9fs_vfs_atomic_open,
1412         .symlink = v9fs_vfs_symlink,
1413         .link = v9fs_vfs_link,
1414         .unlink = v9fs_vfs_unlink,
1415         .mkdir = v9fs_vfs_mkdir,
1416         .rmdir = v9fs_vfs_rmdir,
1417         .mknod = v9fs_vfs_mknod,
1418         .rename = v9fs_vfs_rename,
1419         .getattr = v9fs_vfs_getattr,
1420         .setattr = v9fs_vfs_setattr,
1421 };
1422
1423 static const struct inode_operations v9fs_dir_inode_operations = {
1424         .create = v9fs_vfs_create,
1425         .lookup = v9fs_vfs_lookup,
1426         .atomic_open = v9fs_vfs_atomic_open,
1427         .unlink = v9fs_vfs_unlink,
1428         .mkdir = v9fs_vfs_mkdir,
1429         .rmdir = v9fs_vfs_rmdir,
1430         .mknod = v9fs_vfs_mknod,
1431         .rename = v9fs_vfs_rename,
1432         .getattr = v9fs_vfs_getattr,
1433         .setattr = v9fs_vfs_setattr,
1434 };
1435
1436 static const struct inode_operations v9fs_file_inode_operations = {
1437         .getattr = v9fs_vfs_getattr,
1438         .setattr = v9fs_vfs_setattr,
1439 };
1440
1441 static const struct inode_operations v9fs_symlink_inode_operations = {
1442         .get_link = v9fs_vfs_get_link,
1443         .getattr = v9fs_vfs_getattr,
1444         .setattr = v9fs_vfs_setattr,
1445 };
1446