fs/reiserfs/xattr.c

   1 /*
   2  * linux/fs/reiserfs/xattr.c
   3  *
   4  * Copyright (c) 2002 by Jeff Mahoney, <jeffm@suse.com>
   5  *
   6  */
   7
   8 /*
   9  * In order to implement EA/ACLs in a clean, backwards compatible manner,
  10  * they are implemented as files in a "private" directory.
  11  * Each EA is in it's own file, with the directory layout like so (/ is assumed
  12  * to be relative to fs root). Inside the /.reiserfs_priv/xattrs directory,
  13  * directories named using the capital-hex form of the objectid and
  14  * generation number are used. Inside each directory are individual files
  15  * named with the name of the extended attribute.
  16  *
  17  * So, for objectid 12648430, we could have:
  18  * /.reiserfs_priv/xattrs/C0FFEE.0/system.posix_acl_access
  19  * /.reiserfs_priv/xattrs/C0FFEE.0/system.posix_acl_default
  20  * /.reiserfs_priv/xattrs/C0FFEE.0/user.Content-Type
  21  * .. or similar.
  22  *
  23  * The file contents are the text of the EA. The size is known based on the
  24  * stat data describing the file.
  25  *
  26  * In the case of system.posix_acl_access and system.posix_acl_default, since
  27  * these are special cases for filesystem ACLs, they are interpreted by the
  28  * kernel, in addition, they are negatively and positively cached and attached
  29  * to the inode so that unnecessary lookups are avoided.
  30  */
  31
  32 #include <linux/reiserfs_fs.h>
  33 #include <linux/dcache.h>
  34 #include <linux/namei.h>
  35 #include <linux/errno.h>
  36 #include <linux/fs.h>
  37 #include <linux/file.h>
  38 #include <linux/pagemap.h>
  39 #include <linux/xattr.h>
  40 #include <linux/reiserfs_xattr.h>
  41 #include <linux/reiserfs_acl.h>
  42 #include <asm/uaccess.h>
  43 #include <asm/checksum.h>
  44 #include <linux/smp_lock.h>
  45 #include <linux/stat.h>
  46 #include <asm/semaphore.h>
  47
  48 #define FL_READONLY 128
  49 #define FL_DIR_SEM_HELD 256
  50 #define PRIVROOT_NAME ".reiserfs_priv"
  51 #define XAROOT_NAME   "xattrs"
  52
  53 static struct reiserfs_xattr_handler *find_xattr_handler_prefix(const char
  54                                                                 *prefix);
  55
  56 static struct dentry *create_xa_root(struct super_block *sb)
  57 {
  58         struct dentry *privroot = dget(REISERFS_SB(sb)->priv_root);
  59         struct dentry *xaroot;
  60
  61         /* This needs to be created at mount-time */
  62         if (!privroot)
  63                 return ERR_PTR(-EOPNOTSUPP);
  64
  65         xaroot = lookup_one_len(XAROOT_NAME, privroot, strlen(XAROOT_NAME));
  66         if (IS_ERR(xaroot)) {
  67                 goto out;
  68         } else if (!xaroot->d_inode) {
  69                 int err;
  70                 down(&privroot->d_inode->i_sem);
  71                 err =
  72                     privroot->d_inode->i_op->mkdir(privroot->d_inode, xaroot,
  73                                                    0700);
  74                 up(&privroot->d_inode->i_sem);
  75
  76                 if (err) {
  77                         dput(xaroot);
  78                         dput(privroot);
  79                         return ERR_PTR(err);
  80                 }
  81                 REISERFS_SB(sb)->xattr_root = dget(xaroot);
  82         }
  83
  84       out:
  85         dput(privroot);
  86         return xaroot;
  87 }
  88
  89 /* This will return a dentry, or error, refering to the xa root directory.
  90  * If the xa root doesn't exist yet, the dentry will be returned without
  91  * an associated inode. This dentry can be used with ->mkdir to create
  92  * the xa directory. */
  93 static struct dentry *__get_xa_root(struct super_block *s)
  94 {
  95         struct dentry *privroot = dget(REISERFS_SB(s)->priv_root);
  96         struct dentry *xaroot = NULL;
  97
  98         if (IS_ERR(privroot) || !privroot)
  99                 return privroot;
 100
 101         xaroot = lookup_one_len(XAROOT_NAME, privroot, strlen(XAROOT_NAME));
 102         if (IS_ERR(xaroot)) {
 103                 goto out;
 104         } else if (!xaroot->d_inode) {
 105                 dput(xaroot);
 106                 xaroot = NULL;
 107                 goto out;
 108         }
 109
 110         REISERFS_SB(s)->xattr_root = dget(xaroot);
 111
 112       out:
 113         dput(privroot);
 114         return xaroot;
 115 }
 116
 117 /* Returns the dentry (or NULL) referring to the root of the extended
 118  * attribute directory tree. If it has already been retreived, it is used.
 119  * Otherwise, we attempt to retreive it from disk. It may also return
 120  * a pointer-encoded error.
 121  */
 122 static inline struct dentry *get_xa_root(struct super_block *s)
 123 {
 124         struct dentry *dentry = dget(REISERFS_SB(s)->xattr_root);
 125
 126         if (!dentry)
 127                 dentry = __get_xa_root(s);
 128
 129         return dentry;
 130 }
 131
 132 /* Opens the directory corresponding to the inode's extended attribute store.
 133  * If flags allow, the tree to the directory may be created. If creation is
 134  * prohibited, -ENODATA is returned. */
 135 static struct dentry *open_xa_dir(const struct inode *inode, int flags)
 136 {
 137         struct dentry *xaroot, *xadir;
 138         char namebuf[17];
 139
 140         xaroot = get_xa_root(inode->i_sb);
 141         if (IS_ERR(xaroot)) {
 142                 return xaroot;
 143         } else if (!xaroot) {
 144                 if (flags == 0 || flags & XATTR_CREATE) {
 145                         xaroot = create_xa_root(inode->i_sb);
 146                         if (IS_ERR(xaroot))
 147                                 return xaroot;
 148                 }
 149                 if (!xaroot)
 150                         return ERR_PTR(-ENODATA);
 151         }
 152
 153         /* ok, we have xaroot open */
 154
 155         snprintf(namebuf, sizeof(namebuf), "%X.%X",
 156                  le32_to_cpu(INODE_PKEY(inode)->k_objectid),
 157                  inode->i_generation);
 158         xadir = lookup_one_len(namebuf, xaroot, strlen(namebuf));
 159         if (IS_ERR(xadir)) {
 160                 dput(xaroot);
 161                 return xadir;
 162         }
 163
 164         if (!xadir->d_inode) {
 165                 int err;
 166                 if (flags == 0 || flags & XATTR_CREATE) {
 167                         /* Although there is nothing else trying to create this directory,
 168                          * another directory with the same hash may be created, so we need
 169                          * to protect against that */
 170                         err =
 171                             xaroot->d_inode->i_op->mkdir(xaroot->d_inode, xadir,
 172                                                          0700);
 173                         if (err) {
 174                                 dput(xaroot);
 175                                 dput(xadir);
 176                                 return ERR_PTR(err);
 177                         }
 178                 }
 179                 if (!xadir->d_inode) {
 180                         dput(xaroot);
 181                         dput(xadir);
 182                         return ERR_PTR(-ENODATA);
 183                 }
 184         }
 185
 186         dput(xaroot);
 187         return xadir;
 188 }
 189
 190 /* Returns a dentry corresponding to a specific extended attribute file
 191  * for the inode. If flags allow, the file is created. Otherwise, a
 192  * valid or negative dentry, or an error is returned. */
 193 static struct dentry *get_xa_file_dentry(const struct inode *inode,
 194                                          const char *name, int flags)
 195 {
 196         struct dentry *xadir, *xafile;
 197         int err = 0;
 198
 199         xadir = open_xa_dir(inode, flags);
 200         if (IS_ERR(xadir)) {
 201                 return ERR_PTR(PTR_ERR(xadir));
 202         } else if (xadir && !xadir->d_inode) {
 203                 dput(xadir);
 204                 return ERR_PTR(-ENODATA);
 205         }
 206
 207         xafile = lookup_one_len(name, xadir, strlen(name));
 208         if (IS_ERR(xafile)) {
 209                 dput(xadir);
 210                 return ERR_PTR(PTR_ERR(xafile));
 211         }
 212
 213         if (xafile->d_inode) {  /* file exists */
 214                 if (flags & XATTR_CREATE) {
 215                         err = -EEXIST;
 216                         dput(xafile);
 217                         goto out;
 218                 }
 219         } else if (flags & XATTR_REPLACE || flags & FL_READONLY) {
 220                 goto out;
 221         } else {
 222                 /* inode->i_sem is down, so nothing else can try to create
 223                  * the same xattr */
 224                 err = xadir->d_inode->i_op->create(xadir->d_inode, xafile,
 225                                                    0700 | S_IFREG, NULL);
 226
 227                 if (err) {
 228                         dput(xafile);
 229                         goto out;
 230                 }
 231         }
 232
 233       out:
 234         dput(xadir);
 235         if (err)
 236                 xafile = ERR_PTR(err);
 237         return xafile;
 238 }
 239
 240 /* Opens a file pointer to the attribute associated with inode */
 241 static struct file *open_xa_file(const struct inode *inode, const char *name,
 242                                  int flags)
 243 {
 244         struct dentry *xafile;
 245         struct file *fp;
 246
 247         xafile = get_xa_file_dentry(inode, name, flags);
 248         if (IS_ERR(xafile))
 249                 return ERR_PTR(PTR_ERR(xafile));
 250         else if (!xafile->d_inode) {
 251                 dput(xafile);
 252                 return ERR_PTR(-ENODATA);
 253         }
 254
 255         fp = dentry_open(xafile, NULL, O_RDWR);
 256         /* dentry_open dputs the dentry if it fails */
 257
 258         return fp;
 259 }
 260
 261 /*
 262  * this is very similar to fs/reiserfs/dir.c:reiserfs_readdir, but
 263  * we need to drop the path before calling the filldir struct.  That
 264  * would be a big performance hit to the non-xattr case, so I've copied
 265  * the whole thing for now. --clm
 266  *
 267  * the big difference is that I go backwards through the directory,
 268  * and don't mess with f->f_pos, but the idea is the same.  Do some
 269  * action on each and every entry in the directory.
 270  *
 271  * we're called with i_sem held, so there are no worries about the directory
 272  * changing underneath us.
 273  */
 274 static int __xattr_readdir(struct file *filp, void *dirent, filldir_t filldir)
 275 {
 276         struct inode *inode = filp->f_dentry->d_inode;
 277         struct cpu_key pos_key; /* key of current position in the directory (key of directory entry) */
 278         INITIALIZE_PATH(path_to_entry);
 279         struct buffer_head *bh;
 280         int entry_num;
 281         struct item_head *ih, tmp_ih;
 282         int search_res;
 283         char *local_buf;
 284         loff_t next_pos;
 285         char small_buf[32];     /* avoid kmalloc if we can */
 286         struct reiserfs_de_head *deh;
 287         int d_reclen;
 288         char *d_name;
 289         off_t d_off;
 290         ino_t d_ino;
 291         struct reiserfs_dir_entry de;
 292
 293         /* form key for search the next directory entry using f_pos field of
 294            file structure */
 295         next_pos = max_reiserfs_offset(inode);
 296
 297         while (1) {
 298               research:
 299                 if (next_pos <= DOT_DOT_OFFSET)
 300                         break;
 301                 make_cpu_key(&pos_key, inode, next_pos, TYPE_DIRENTRY, 3);
 302
 303                 search_res =
 304                     search_by_entry_key(inode->i_sb, &pos_key, &path_to_entry,
 305                                         &de);
 306                 if (search_res == IO_ERROR) {
 307                         // FIXME: we could just skip part of directory which could
 308                         // not be read
 309                         pathrelse(&path_to_entry);
 310                         return -EIO;
 311                 }
 312
 313                 if (search_res == NAME_NOT_FOUND)
 314                         de.de_entry_num--;
 315
 316                 set_de_name_and_namelen(&de);
 317                 entry_num = de.de_entry_num;
 318                 deh = &(de.de_deh[entry_num]);
 319
 320                 bh = de.de_bh;
 321                 ih = de.de_ih;
 322
 323                 if (!is_direntry_le_ih(ih)) {
 324                         reiserfs_warning(inode->i_sb, "not direntry %h", ih);
 325                         break;
 326                 }
 327                 copy_item_head(&tmp_ih, ih);
 328
 329                 /* we must have found item, that is item of this directory, */
 330                 RFALSE(COMP_SHORT_KEYS(&(ih->ih_key), &pos_key),
 331                        "vs-9000: found item %h does not match to dir we readdir %K",
 332                        ih, &pos_key);
 333
 334                 if (deh_offset(deh) <= DOT_DOT_OFFSET) {
 335                         break;
 336                 }
 337
 338                 /* look for the previous entry in the directory */
 339                 next_pos = deh_offset(deh) - 1;
 340
 341                 if (!de_visible(deh))
 342                         /* it is hidden entry */
 343                         continue;
 344
 345                 d_reclen = entry_length(bh, ih, entry_num);
 346                 d_name = B_I_DEH_ENTRY_FILE_NAME(bh, ih, deh);
 347                 d_off = deh_offset(deh);
 348                 d_ino = deh_objectid(deh);
 349
 350                 if (!d_name[d_reclen - 1])
 351                         d_reclen = strlen(d_name);
 352
 353                 if (d_reclen > REISERFS_MAX_NAME(inode->i_sb->s_blocksize)) {
 354                         /* too big to send back to VFS */
 355                         continue;
 356                 }
 357
 358                 /* Ignore the .reiserfs_priv entry */
 359                 if (reiserfs_xattrs(inode->i_sb) &&
 360                     !old_format_only(inode->i_sb) &&
 361                     deh_objectid(deh) ==
 362                     le32_to_cpu(INODE_PKEY
 363                                 (REISERFS_SB(inode->i_sb)->priv_root->d_inode)->
 364                                 k_objectid))
 365                         continue;
 366
 367                 if (d_reclen <= 32) {
 368                         local_buf = small_buf;
 369                 } else {
 370                         local_buf =
 371                             reiserfs_kmalloc(d_reclen, GFP_NOFS, inode->i_sb);
 372                         if (!local_buf) {
 373                                 pathrelse(&path_to_entry);
 374                                 return -ENOMEM;
 375                         }
 376                         if (item_moved(&tmp_ih, &path_to_entry)) {
 377                                 reiserfs_kfree(local_buf, d_reclen,
 378                                                inode->i_sb);
 379
 380                                 /* sigh, must retry.  Do this same offset again */
 381                                 next_pos = d_off;
 382                                 goto research;
 383                         }
 384                 }
 385
 386                 // Note, that we copy name to user space via temporary
 387                 // buffer (local_buf) because filldir will block if
 388                 // user space buffer is swapped out. At that time
 389                 // entry can move to somewhere else
 390                 memcpy(local_buf, d_name, d_reclen);
 391
 392                 /* the filldir function might need to start transactions,
 393                  * or do who knows what.  Release the path now that we've
 394                  * copied all the important stuff out of the deh
 395                  */
 396                 pathrelse(&path_to_entry);
 397
 398                 if (filldir(dirent, local_buf, d_reclen, d_off, d_ino,
 399                             DT_UNKNOWN) < 0) {
 400                         if (local_buf != small_buf) {
 401                                 reiserfs_kfree(local_buf, d_reclen,
 402                                                inode->i_sb);
 403                         }
 404                         goto end;
 405                 }
 406                 if (local_buf != small_buf) {
 407                         reiserfs_kfree(local_buf, d_reclen, inode->i_sb);
 408                 }
 409         }                       /* while */
 410
 411       end:
 412         pathrelse(&path_to_entry);
 413         return 0;
 414 }
 415
 416 /*
 417  * this could be done with dedicated readdir ops for the xattr files,
 418  * but I want to get something working asap
 419  * this is stolen from vfs_readdir
 420  *
 421  */
 422 static
 423 int xattr_readdir(struct file *file, filldir_t filler, void *buf)
 424 {
 425         struct inode *inode = file->f_dentry->d_inode;
 426         int res = -ENOTDIR;
 427         if (!file->f_op || !file->f_op->readdir)
 428                 goto out;
 429         down(&inode->i_sem);
 430 //        down(&inode->i_zombie);
 431         res = -ENOENT;
 432         if (!IS_DEADDIR(inode)) {
 433                 lock_kernel();
 434                 res = __xattr_readdir(file, buf, filler);
 435                 unlock_kernel();
 436         }
 437 //        up(&inode->i_zombie);
 438         up(&inode->i_sem);
 439       out:
 440         return res;
 441 }
 442
 443 /* Internal operations on file data */
 444 static inline void reiserfs_put_page(struct page *page)
 445 {
 446         kunmap(page);
 447         page_cache_release(page);
 448 }
 449
 450 static struct page *reiserfs_get_page(struct inode *dir, unsigned long n)
 451 {
 452         struct address_space *mapping = dir->i_mapping;
 453         struct page *page;
 454         /* We can deadlock if we try to free dentries,
 455            and an unlink/rmdir has just occured - GFP_NOFS avoids this */
 456         mapping->flags = (mapping->flags & ~__GFP_BITS_MASK) | GFP_NOFS;
 457         page = read_cache_page(mapping, n,
 458                                (filler_t *) mapping->a_ops->readpage, NULL);
 459         if (!IS_ERR(page)) {
 460                 wait_on_page_locked(page);
 461                 kmap(page);
 462                 if (!PageUptodate(page))
 463                         goto fail;
 464
 465                 if (PageError(page))
 466                         goto fail;
 467         }
 468         return page;
 469
 470       fail:
 471         reiserfs_put_page(page);
 472         return ERR_PTR(-EIO);
 473 }
 474
 475 static inline __u32 xattr_hash(const char *msg, int len)
 476 {
 477         return csum_partial(msg, len, 0);
 478 }
 479
 480 /* Generic extended attribute operations that can be used by xa plugins */
 481
 482 /*
 483  * inode->i_sem: down
 484  */
 485 int
 486 reiserfs_xattr_set(struct inode *inode, const char *name, const void *buffer,
 487                    size_t buffer_size, int flags)
 488 {
 489         int err = 0;
 490         struct file *fp;
 491         struct page *page;
 492         char *data;
 493         struct address_space *mapping;
 494         size_t file_pos = 0;
 495         size_t buffer_pos = 0;
 496         struct inode *xinode;
 497         struct iattr newattrs;
 498         __u32 xahash = 0;
 499
 500         if (IS_RDONLY(inode))
 501                 return -EROFS;
 502
 503         if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
 504                 return -EPERM;
 505
 506         if (get_inode_sd_version(inode) == STAT_DATA_V1)
 507                 return -EOPNOTSUPP;
 508
 509         /* Empty xattrs are ok, they're just empty files, no hash */
 510         if (buffer && buffer_size)
 511                 xahash = xattr_hash(buffer, buffer_size);
 512
 513       open_file:
 514         fp = open_xa_file(inode, name, flags);
 515         if (IS_ERR(fp)) {
 516                 err = PTR_ERR(fp);
 517                 goto out;
 518         }
 519
 520         xinode = fp->f_dentry->d_inode;
 521         REISERFS_I(inode)->i_flags |= i_has_xattr_dir;
 522
 523         /* we need to copy it off.. */
 524         if (xinode->i_nlink > 1) {
 525                 fput(fp);
 526                 err = reiserfs_xattr_del(inode, name);
 527                 if (err < 0)
 528                         goto out;
 529                 /* We just killed the old one, we're not replacing anymore */
 530                 if (flags & XATTR_REPLACE)
 531                         flags &= ~XATTR_REPLACE;
 532                 goto open_file;
 533         }
 534
 535         /* Resize it so we're ok to write there */
 536         newattrs.ia_size = buffer_size;
 537         newattrs.ia_valid = ATTR_SIZE | ATTR_CTIME;
 538         down(&xinode->i_sem);
 539         err = notify_change(fp->f_dentry, &newattrs);
 540         if (err)
 541                 goto out_filp;
 542
 543         mapping = xinode->i_mapping;
 544         while (buffer_pos < buffer_size || buffer_pos == 0) {
 545                 size_t chunk;
 546                 size_t skip = 0;
 547                 size_t page_offset = (file_pos & (PAGE_CACHE_SIZE - 1));
 548                 if (buffer_size - buffer_pos > PAGE_CACHE_SIZE)
 549                         chunk = PAGE_CACHE_SIZE;
 550                 else
 551                         chunk = buffer_size - buffer_pos;
 552
 553                 page = reiserfs_get_page(xinode, file_pos >> PAGE_CACHE_SHIFT);
 554                 if (IS_ERR(page)) {
 555                         err = PTR_ERR(page);
 556                         goto out_filp;
 557                 }
 558
 559                 lock_page(page);
 560                 data = page_address(page);
 561
 562                 if (file_pos == 0) {
 563                         struct reiserfs_xattr_header *rxh;
 564                         skip = file_pos = sizeof(struct reiserfs_xattr_header);
 565                         if (chunk + skip > PAGE_CACHE_SIZE)
 566                                 chunk = PAGE_CACHE_SIZE - skip;
 567                         rxh = (struct reiserfs_xattr_header *)data;
 568                         rxh->h_magic = cpu_to_le32(REISERFS_XATTR_MAGIC);
 569                         rxh->h_hash = cpu_to_le32(xahash);
 570                 }
 571
 572                 err = mapping->a_ops->prepare_write(fp, page, page_offset,
 573                                                     page_offset + chunk + skip);
 574                 if (!err) {
 575                         if (buffer)
 576                                 memcpy(data + skip, buffer + buffer_pos, chunk);
 577                         err =
 578                             mapping->a_ops->commit_write(fp, page, page_offset,
 579                                                          page_offset + chunk +
 580                                                          skip);
 581                 }
 582                 unlock_page(page);
 583                 reiserfs_put_page(page);
 584                 buffer_pos += chunk;
 585                 file_pos += chunk;
 586                 skip = 0;
 587                 if (err || buffer_size == 0 || !buffer)
 588                         break;
 589         }
 590
 591         /* We can't mark the inode dirty if it's not hashed. This is the case
 592          * when we're inheriting the default ACL. If we dirty it, the inode
 593          * gets marked dirty, but won't (ever) make it onto the dirty list until
 594          * it's synced explicitly to clear I_DIRTY. This is bad. */
 595         if (!hlist_unhashed(&inode->i_hash)) {
 596                 inode->i_ctime = CURRENT_TIME_SEC;
 597                 mark_inode_dirty(inode);
 598         }
 599
 600       out_filp:
 601         up(&xinode->i_sem);
 602         fput(fp);
 603
 604       out:
 605         return err;
 606 }
 607
 608 /*
 609  * inode->i_sem: down
 610  */
 611 int
 612 reiserfs_xattr_get(const struct inode *inode, const char *name, void *buffer,
 613                    size_t buffer_size)
 614 {
 615         ssize_t err = 0;
 616         struct file *fp;
 617         size_t isize;
 618         size_t file_pos = 0;
 619         size_t buffer_pos = 0;
 620         struct page *page;
 621         struct inode *xinode;
 622         __u32 hash = 0;
 623
 624         if (name == NULL)
 625                 return -EINVAL;
 626
 627         /* We can't have xattrs attached to v1 items since they don't have
 628          * generation numbers */
 629         if (get_inode_sd_version(inode) == STAT_DATA_V1)
 630                 return -EOPNOTSUPP;
 631
 632         fp = open_xa_file(inode, name, FL_READONLY);
 633         if (IS_ERR(fp)) {
 634                 err = PTR_ERR(fp);
 635                 goto out;
 636         }
 637
 638         xinode = fp->f_dentry->d_inode;
 639         isize = xinode->i_size;
 640         REISERFS_I(inode)->i_flags |= i_has_xattr_dir;
 641
 642         /* Just return the size needed */
 643         if (buffer == NULL) {
 644                 err = isize - sizeof(struct reiserfs_xattr_header);
 645                 goto out_dput;
 646         }
 647
 648         if (buffer_size < isize - sizeof(struct reiserfs_xattr_header)) {
 649                 err = -ERANGE;
 650                 goto out_dput;
 651         }
 652
 653         while (file_pos < isize) {
 654                 size_t chunk;
 655                 char *data;
 656                 size_t skip = 0;
 657                 if (isize - file_pos > PAGE_CACHE_SIZE)
 658                         chunk = PAGE_CACHE_SIZE;
 659                 else
 660                         chunk = isize - file_pos;
 661
 662                 page = reiserfs_get_page(xinode, file_pos >> PAGE_CACHE_SHIFT);
 663                 if (IS_ERR(page)) {
 664                         err = PTR_ERR(page);
 665                         goto out_dput;
 666                 }
 667
 668                 lock_page(page);
 669                 data = page_address(page);
 670                 if (file_pos == 0) {
 671                         struct reiserfs_xattr_header *rxh =
 672                             (struct reiserfs_xattr_header *)data;
 673                         skip = file_pos = sizeof(struct reiserfs_xattr_header);
 674                         chunk -= skip;
 675                         /* Magic doesn't match up.. */
 676                         if (rxh->h_magic != cpu_to_le32(REISERFS_XATTR_MAGIC)) {
 677                                 unlock_page(page);
 678                                 reiserfs_put_page(page);
 679                                 reiserfs_warning(inode->i_sb,
 680                                                  "Invalid magic for xattr (%s) "
 681                                                  "associated with %k", name,
 682                                                  INODE_PKEY(inode));
 683                                 err = -EIO;
 684                                 goto out_dput;
 685                         }
 686                         hash = le32_to_cpu(rxh->h_hash);
 687                 }
 688                 memcpy(buffer + buffer_pos, data + skip, chunk);
 689                 unlock_page(page);
 690                 reiserfs_put_page(page);
 691                 file_pos += chunk;
 692                 buffer_pos += chunk;
 693                 skip = 0;
 694         }
 695         err = isize - sizeof(struct reiserfs_xattr_header);
 696
 697         if (xattr_hash(buffer, isize - sizeof(struct reiserfs_xattr_header)) !=
 698             hash) {
 699                 reiserfs_warning(inode->i_sb,
 700                                  "Invalid hash for xattr (%s) associated "
 701                                  "with %k", name, INODE_PKEY(inode));
 702                 err = -EIO;
 703         }
 704
 705       out_dput:
 706         fput(fp);
 707
 708       out:
 709         return err;
 710 }
 711
 712 static int
 713 __reiserfs_xattr_del(struct dentry *xadir, const char *name, int namelen)
 714 {
 715         struct dentry *dentry;
 716         struct inode *dir = xadir->d_inode;
 717         int err = 0;
 718
 719         dentry = lookup_one_len(name, xadir, namelen);
 720         if (IS_ERR(dentry)) {
 721                 err = PTR_ERR(dentry);
 722                 goto out;
 723         } else if (!dentry->d_inode) {
 724                 err = -ENODATA;
 725                 goto out_file;
 726         }
 727
 728         /* Skip directories.. */
 729         if (S_ISDIR(dentry->d_inode->i_mode))
 730                 goto out_file;
 731
 732         if (!is_reiserfs_priv_object(dentry->d_inode)) {
 733                 reiserfs_warning(dir->i_sb, "OID %08x [%.*s/%.*s] doesn't have "
 734                                  "priv flag set [parent is %sset].",
 735                                  le32_to_cpu(INODE_PKEY(dentry->d_inode)->
 736                                              k_objectid), xadir->d_name.len,
 737                                  xadir->d_name.name, namelen, name,
 738                                  is_reiserfs_priv_object(xadir->
 739                                                          d_inode) ? "" :
 740                                  "not ");
 741                 dput(dentry);
 742                 return -EIO;
 743         }
 744
 745         err = dir->i_op->unlink(dir, dentry);
 746         if (!err)
 747                 d_delete(dentry);
 748
 749       out_file:
 750         dput(dentry);
 751
 752       out:
 753         return err;
 754 }
 755
 756 int reiserfs_xattr_del(struct inode *inode, const char *name)
 757 {
 758         struct dentry *dir;
 759         int err;
 760
 761         if (IS_RDONLY(inode))
 762                 return -EROFS;
 763
 764         dir = open_xa_dir(inode, FL_READONLY);
 765         if (IS_ERR(dir)) {
 766                 err = PTR_ERR(dir);
 767                 goto out;
 768         }
 769
 770         err = __reiserfs_xattr_del(dir, name, strlen(name));
 771         dput(dir);
 772
 773         if (!err) {
 774                 inode->i_ctime = CURRENT_TIME_SEC;
 775                 mark_inode_dirty(inode);
 776         }
 777
 778       out:
 779         return err;
 780 }
 781
 782 /* The following are side effects of other operations that aren't explicitly
 783  * modifying extended attributes. This includes operations such as permissions
 784  * or ownership changes, object deletions, etc. */
 785
 786 static int
 787 reiserfs_delete_xattrs_filler(void *buf, const char *name, int namelen,
 788                               loff_t offset, ino_t ino, unsigned int d_type)
 789 {
 790         struct dentry *xadir = (struct dentry *)buf;
 791
 792         return __reiserfs_xattr_del(xadir, name, namelen);
 793
 794 }
 795
 796 /* This is called w/ inode->i_sem downed */
 797 int reiserfs_delete_xattrs(struct inode *inode)
 798 {
 799         struct file *fp;
 800         struct dentry *dir, *root;
 801         int err = 0;
 802
 803         /* Skip out, an xattr has no xattrs associated with it */
 804         if (is_reiserfs_priv_object(inode) ||
 805             get_inode_sd_version(inode) == STAT_DATA_V1 ||
 806             !reiserfs_xattrs(inode->i_sb)) {
 807                 return 0;
 808         }
 809         reiserfs_read_lock_xattrs(inode->i_sb);
 810         dir = open_xa_dir(inode, FL_READONLY);
 811         reiserfs_read_unlock_xattrs(inode->i_sb);
 812         if (IS_ERR(dir)) {
 813                 err = PTR_ERR(dir);
 814                 goto out;
 815         } else if (!dir->d_inode) {
 816                 dput(dir);
 817                 return 0;
 818         }
 819
 820         fp = dentry_open(dir, NULL, O_RDWR);
 821         if (IS_ERR(fp)) {
 822                 err = PTR_ERR(fp);
 823                 /* dentry_open dputs the dentry if it fails */
 824                 goto out;
 825         }
 826
 827         lock_kernel();
 828         err = xattr_readdir(fp, reiserfs_delete_xattrs_filler, dir);
 829         if (err) {
 830                 unlock_kernel();
 831                 goto out_dir;
 832         }
 833
 834         /* Leftovers besides . and .. -- that's not good. */
 835         if (dir->d_inode->i_nlink <= 2) {
 836                 root = get_xa_root(inode->i_sb);
 837                 reiserfs_write_lock_xattrs(inode->i_sb);
 838                 err = vfs_rmdir(root->d_inode, dir);
 839                 reiserfs_write_unlock_xattrs(inode->i_sb);
 840                 dput(root);
 841         } else {
 842                 reiserfs_warning(inode->i_sb,
 843                                  "Couldn't remove all entries in directory");
 844         }
 845         unlock_kernel();
 846
 847       out_dir:
 848         fput(fp);
 849
 850       out:
 851         if (!err)
 852                 REISERFS_I(inode)->i_flags =
 853                     REISERFS_I(inode)->i_flags & ~i_has_xattr_dir;
 854         return err;
 855 }
 856
 857 struct reiserfs_chown_buf {
 858         struct inode *inode;
 859         struct dentry *xadir;
 860         struct iattr *attrs;
 861 };
 862
 863 /* XXX: If there is a better way to do this, I'd love to hear about it */
 864 static int
 865 reiserfs_chown_xattrs_filler(void *buf, const char *name, int namelen,
 866                              loff_t offset, ino_t ino, unsigned int d_type)
 867 {
 868         struct reiserfs_chown_buf *chown_buf = (struct reiserfs_chown_buf *)buf;
 869         struct dentry *xafile, *xadir = chown_buf->xadir;
 870         struct iattr *attrs = chown_buf->attrs;
 871         int err = 0;
 872
 873         xafile = lookup_one_len(name, xadir, namelen);
 874         if (IS_ERR(xafile))
 875                 return PTR_ERR(xafile);
 876         else if (!xafile->d_inode) {
 877                 dput(xafile);
 878                 return -ENODATA;
 879         }
 880
 881         if (!S_ISDIR(xafile->d_inode->i_mode))
 882                 err = notify_change(xafile, attrs);
 883         dput(xafile);
 884
 885         return err;
 886 }
 887
 888 int reiserfs_chown_xattrs(struct inode *inode, struct iattr *attrs)
 889 {
 890         struct file *fp;
 891         struct dentry *dir;
 892         int err = 0;
 893         struct reiserfs_chown_buf buf;
 894         unsigned int ia_valid = attrs->ia_valid;
 895
 896         /* Skip out, an xattr has no xattrs associated with it */
 897         if (is_reiserfs_priv_object(inode) ||
 898             get_inode_sd_version(inode) == STAT_DATA_V1 ||
 899             !reiserfs_xattrs(inode->i_sb)) {
 900                 return 0;
 901         }
 902         reiserfs_read_lock_xattrs(inode->i_sb);
 903         dir = open_xa_dir(inode, FL_READONLY);
 904         reiserfs_read_unlock_xattrs(inode->i_sb);
 905         if (IS_ERR(dir)) {
 906                 if (PTR_ERR(dir) != -ENODATA)
 907                         err = PTR_ERR(dir);
 908                 goto out;
 909         } else if (!dir->d_inode) {
 910                 dput(dir);
 911                 goto out;
 912         }
 913
 914         fp = dentry_open(dir, NULL, O_RDWR);
 915         if (IS_ERR(fp)) {
 916                 err = PTR_ERR(fp);
 917                 /* dentry_open dputs the dentry if it fails */
 918                 goto out;
 919         }
 920
 921         lock_kernel();
 922
 923         attrs->ia_valid &= (ATTR_UID | ATTR_GID | ATTR_CTIME);
 924         buf.xadir = dir;
 925         buf.attrs = attrs;
 926         buf.inode = inode;
 927
 928         err = xattr_readdir(fp, reiserfs_chown_xattrs_filler, &buf);
 929         if (err) {
 930                 unlock_kernel();
 931                 goto out_dir;
 932         }
 933
 934         err = notify_change(dir, attrs);
 935         unlock_kernel();
 936
 937       out_dir:
 938         fput(fp);
 939
 940       out:
 941         attrs->ia_valid = ia_valid;
 942         return err;
 943 }
 944
 945 /* Actual operations that are exported to VFS-land */
 946
 947 /*
 948  * Inode operation getxattr()
 949  * Preliminary locking: we down dentry->d_inode->i_sem
 950  */
 951 ssize_t
 952 reiserfs_getxattr(struct dentry * dentry, const char *name, void *buffer,
 953                   size_t size)
 954 {
 955         struct reiserfs_xattr_handler *xah = find_xattr_handler_prefix(name);
 956         int err;
 957
 958         if (!xah || !reiserfs_xattrs(dentry->d_sb) ||
 959             get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1)
 960                 return -EOPNOTSUPP;
 961
 962         reiserfs_read_lock_xattr_i(dentry->d_inode);
 963         reiserfs_read_lock_xattrs(dentry->d_sb);
 964         err = xah->get(dentry->d_inode, name, buffer, size);
 965         reiserfs_read_unlock_xattrs(dentry->d_sb);
 966         reiserfs_read_unlock_xattr_i(dentry->d_inode);
 967         return err;
 968 }
 969
 970 /*
 971  * Inode operation setxattr()
 972  *
 973  * dentry->d_inode->i_sem down
 974  */
 975 int
 976 reiserfs_setxattr(struct dentry *dentry, const char *name, const void *value,
 977                   size_t size, int flags)
 978 {
 979         struct reiserfs_xattr_handler *xah = find_xattr_handler_prefix(name);
 980         int err;
 981         int lock;
 982
 983         if (!xah || !reiserfs_xattrs(dentry->d_sb) ||
 984             get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1)
 985                 return -EOPNOTSUPP;
 986
 987         if (IS_RDONLY(dentry->d_inode))
 988                 return -EROFS;
 989
 990         if (IS_IMMUTABLE(dentry->d_inode) || IS_APPEND(dentry->d_inode))
 991                 return -EROFS;
 992
 993         reiserfs_write_lock_xattr_i(dentry->d_inode);
 994         lock = !has_xattr_dir(dentry->d_inode);
 995         if (lock)
 996                 reiserfs_write_lock_xattrs(dentry->d_sb);
 997         else
 998                 reiserfs_read_lock_xattrs(dentry->d_sb);
 999         err = xah->set(dentry->d_inode, name, value, size, flags);
1000         if (lock)
1001                 reiserfs_write_unlock_xattrs(dentry->d_sb);
1002         else
1003                 reiserfs_read_unlock_xattrs(dentry->d_sb);
1004         reiserfs_write_unlock_xattr_i(dentry->d_inode);
1005         return err;
1006 }
1007
1008 /*
1009  * Inode operation removexattr()
1010  *
1011  * dentry->d_inode->i_sem down
1012  */
1013 int reiserfs_removexattr(struct dentry *dentry, const char *name)
1014 {
1015         int err;
1016         struct reiserfs_xattr_handler *xah = find_xattr_handler_prefix(name);
1017
1018         if (!xah || !reiserfs_xattrs(dentry->d_sb) ||
1019             get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1)
1020                 return -EOPNOTSUPP;
1021
1022         if (IS_RDONLY(dentry->d_inode))
1023                 return -EROFS;
1024
1025         if (IS_IMMUTABLE(dentry->d_inode) || IS_APPEND(dentry->d_inode))
1026                 return -EPERM;
1027
1028         reiserfs_write_lock_xattr_i(dentry->d_inode);
1029         reiserfs_read_lock_xattrs(dentry->d_sb);
1030
1031         /* Deletion pre-operation */
1032         if (xah->del) {
1033                 err = xah->del(dentry->d_inode, name);
1034                 if (err)
1035                         goto out;
1036         }
1037
1038         err = reiserfs_xattr_del(dentry->d_inode, name);
1039
1040         dentry->d_inode->i_ctime = CURRENT_TIME_SEC;
1041         mark_inode_dirty(dentry->d_inode);
1042
1043       out:
1044         reiserfs_read_unlock_xattrs(dentry->d_sb);
1045         reiserfs_write_unlock_xattr_i(dentry->d_inode);
1046         return err;
1047 }
1048
1049 /* This is what filldir will use:
1050  * r_pos will always contain the amount of space required for the entire
1051  * list. If r_pos becomes larger than r_size, we need more space and we
1052  * return an error indicating this. If r_pos is less than r_size, then we've
1053  * filled the buffer successfully and we return success */
1054 struct reiserfs_listxattr_buf {
1055         int r_pos;
1056         int r_size;
1057         char *r_buf;
1058         struct inode *r_inode;
1059 };
1060
1061 static int
1062 reiserfs_listxattr_filler(void *buf, const char *name, int namelen,
1063                           loff_t offset, ino_t ino, unsigned int d_type)
1064 {
1065         struct reiserfs_listxattr_buf *b = (struct reiserfs_listxattr_buf *)buf;
1066         int len = 0;
1067         if (name[0] != '.'
1068             || (namelen != 1 && (name[1] != '.' || namelen != 2))) {
1069                 struct reiserfs_xattr_handler *xah =
1070                     find_xattr_handler_prefix(name);
1071                 if (!xah)
1072                         return 0;       /* Unsupported xattr name, skip it */
1073
1074                 /* We call ->list() twice because the operation isn't required to just
1075                  * return the name back - we want to make sure we have enough space */
1076                 len += xah->list(b->r_inode, name, namelen, NULL);
1077
1078                 if (len) {
1079                         if (b->r_pos + len + 1 <= b->r_size) {
1080                                 char *p = b->r_buf + b->r_pos;
1081                                 p += xah->list(b->r_inode, name, namelen, p);
1082                                 *p++ = '\0';
1083                         }
1084                         b->r_pos += len + 1;
1085                 }
1086         }
1087
1088         return 0;
1089 }
1090
1091 /*
1092  * Inode operation listxattr()
1093  *
1094  * Preliminary locking: we down dentry->d_inode->i_sem
1095  */
1096 ssize_t reiserfs_listxattr(struct dentry * dentry, char *buffer, size_t size)
1097 {
1098         struct file *fp;
1099         struct dentry *dir;
1100         int err = 0;
1101         struct reiserfs_listxattr_buf buf;
1102
1103         if (!dentry->d_inode)
1104                 return -EINVAL;
1105
1106         if (!reiserfs_xattrs(dentry->d_sb) ||
1107             get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1)
1108                 return -EOPNOTSUPP;
1109
1110         reiserfs_read_lock_xattr_i(dentry->d_inode);
1111         reiserfs_read_lock_xattrs(dentry->d_sb);
1112         dir = open_xa_dir(dentry->d_inode, FL_READONLY);
1113         reiserfs_read_unlock_xattrs(dentry->d_sb);
1114         if (IS_ERR(dir)) {
1115                 err = PTR_ERR(dir);
1116                 if (err == -ENODATA)
1117                         err = 0;        /* Not an error if there aren't any xattrs */
1118                 goto out;
1119         }
1120
1121         fp = dentry_open(dir, NULL, O_RDWR);
1122         if (IS_ERR(fp)) {
1123                 err = PTR_ERR(fp);
1124                 /* dentry_open dputs the dentry if it fails */
1125                 goto out;
1126         }
1127
1128         buf.r_buf = buffer;
1129         buf.r_size = buffer ? size : 0;
1130         buf.r_pos = 0;
1131         buf.r_inode = dentry->d_inode;
1132
1133         REISERFS_I(dentry->d_inode)->i_flags |= i_has_xattr_dir;
1134
1135         err = xattr_readdir(fp, reiserfs_listxattr_filler, &buf);
1136         if (err)
1137                 goto out_dir;
1138
1139         if (buf.r_pos > buf.r_size && buffer != NULL)
1140                 err = -ERANGE;
1141         else
1142                 err = buf.r_pos;
1143
1144       out_dir:
1145         fput(fp);
1146
1147       out:
1148         reiserfs_read_unlock_xattr_i(dentry->d_inode);
1149         return err;
1150 }
1151
1152 /* This is the implementation for the xattr plugin infrastructure */
1153 static struct list_head xattr_handlers = LIST_HEAD_INIT(xattr_handlers);
1154 static DEFINE_RWLOCK(handler_lock);
1155
1156 static struct reiserfs_xattr_handler *find_xattr_handler_prefix(const char
1157                                                                 *prefix)
1158 {
1159         struct reiserfs_xattr_handler *xah = NULL;
1160         struct list_head *p;
1161
1162         read_lock(&handler_lock);
1163         list_for_each(p, &xattr_handlers) {
1164                 xah = list_entry(p, struct reiserfs_xattr_handler, handlers);
1165                 if (strncmp(xah->prefix, prefix, strlen(xah->prefix)) == 0)
1166                         break;
1167                 xah = NULL;
1168         }
1169
1170         read_unlock(&handler_lock);
1171         return xah;
1172 }
1173
1174 static void __unregister_handlers(void)
1175 {
1176         struct reiserfs_xattr_handler *xah;
1177         struct list_head *p, *tmp;
1178
1179         list_for_each_safe(p, tmp, &xattr_handlers) {
1180                 xah = list_entry(p, struct reiserfs_xattr_handler, handlers);
1181                 if (xah->exit)
1182                         xah->exit();
1183
1184                 list_del_init(p);
1185         }
1186         INIT_LIST_HEAD(&xattr_handlers);
1187 }
1188
1189 int __init reiserfs_xattr_register_handlers(void)
1190 {
1191         int err = 0;
1192         struct reiserfs_xattr_handler *xah;
1193         struct list_head *p;
1194
1195         write_lock(&handler_lock);
1196
1197         /* If we're already initialized, nothing to do */
1198         if (!list_empty(&xattr_handlers)) {
1199                 write_unlock(&handler_lock);
1200                 return 0;
1201         }
1202
1203         /* Add the handlers */
1204         list_add_tail(&user_handler.handlers, &xattr_handlers);
1205         list_add_tail(&trusted_handler.handlers, &xattr_handlers);
1206 #ifdef CONFIG_REISERFS_FS_SECURITY
1207         list_add_tail(&security_handler.handlers, &xattr_handlers);
1208 #endif
1209 #ifdef CONFIG_REISERFS_FS_POSIX_ACL
1210         list_add_tail(&posix_acl_access_handler.handlers, &xattr_handlers);
1211         list_add_tail(&posix_acl_default_handler.handlers, &xattr_handlers);
1212 #endif
1213
1214         /* Run initializers, if available */
1215         list_for_each(p, &xattr_handlers) {
1216                 xah = list_entry(p, struct reiserfs_xattr_handler, handlers);
1217                 if (xah->init) {
1218                         err = xah->init();
1219                         if (err) {
1220                                 list_del_init(p);
1221                                 break;
1222                         }
1223                 }
1224         }
1225
1226         /* Clean up other handlers, if any failed */
1227         if (err)
1228                 __unregister_handlers();
1229
1230         write_unlock(&handler_lock);
1231         return err;
1232 }
1233
1234 void reiserfs_xattr_unregister_handlers(void)
1235 {
1236         write_lock(&handler_lock);
1237         __unregister_handlers();
1238         write_unlock(&handler_lock);
1239 }
1240
1241 /* This will catch lookups from the fs root to .reiserfs_priv */
1242 static int
1243 xattr_lookup_poison(struct dentry *dentry, struct qstr *q1, struct qstr *name)
1244 {
1245         struct dentry *priv_root = REISERFS_SB(dentry->d_sb)->priv_root;
1246         if (name->len == priv_root->d_name.len &&
1247             name->hash == priv_root->d_name.hash &&
1248             !memcmp(name->name, priv_root->d_name.name, name->len)) {
1249                 return -ENOENT;
1250         } else if (q1->len == name->len &&
1251                    !memcmp(q1->name, name->name, name->len))
1252                 return 0;
1253         return 1;
1254 }
1255
1256 static struct dentry_operations xattr_lookup_poison_ops = {
1257         .d_compare = xattr_lookup_poison,
1258 };
1259
1260 /* We need to take a copy of the mount flags since things like
1261  * MS_RDONLY don't get set until *after* we're called.
1262  * mount_flags != mount_options */
1263 int reiserfs_xattr_init(struct super_block *s, int mount_flags)
1264 {
1265         int err = 0;
1266
1267         /* We need generation numbers to ensure that the oid mapping is correct
1268          * v3.5 filesystems don't have them. */
1269         if (!old_format_only(s)) {
1270                 set_bit(REISERFS_XATTRS, &(REISERFS_SB(s)->s_mount_opt));
1271         } else if (reiserfs_xattrs_optional(s)) {
1272                 /* Old format filesystem, but optional xattrs have been enabled
1273                  * at mount time. Error out. */
1274                 reiserfs_warning(s, "xattrs/ACLs not supported on pre v3.6 "
1275                                  "format filesystem. Failing mount.");
1276                 err = -EOPNOTSUPP;
1277                 goto error;
1278         } else {
1279                 /* Old format filesystem, but no optional xattrs have been enabled. This
1280                  * means we silently disable xattrs on the filesystem. */
1281                 clear_bit(REISERFS_XATTRS, &(REISERFS_SB(s)->s_mount_opt));
1282         }
1283
1284         /* If we don't have the privroot located yet - go find it */
1285         if (reiserfs_xattrs(s) && !REISERFS_SB(s)->priv_root) {
1286                 struct dentry *dentry;
1287                 dentry = lookup_one_len(PRIVROOT_NAME, s->s_root,
1288                                         strlen(PRIVROOT_NAME));
1289                 if (!IS_ERR(dentry)) {
1290                         if (!(mount_flags & MS_RDONLY) && !dentry->d_inode) {
1291                                 struct inode *inode = dentry->d_parent->d_inode;
1292                                 down(&inode->i_sem);
1293                                 err = inode->i_op->mkdir(inode, dentry, 0700);
1294                                 up(&inode->i_sem);
1295                                 if (err) {
1296                                         dput(dentry);
1297                                         dentry = NULL;
1298                                 }
1299
1300                                 if (dentry && dentry->d_inode)
1301                                         reiserfs_warning(s,
1302                                                          "Created %s on %s - reserved for "
1303                                                          "xattr storage.",
1304                                                          PRIVROOT_NAME,
1305                                                          reiserfs_bdevname
1306                                                          (inode->i_sb));
1307                         } else if (!dentry->d_inode) {
1308                                 dput(dentry);
1309                                 dentry = NULL;
1310                         }
1311                 } else
1312                         err = PTR_ERR(dentry);
1313
1314                 if (!err && dentry) {
1315                         s->s_root->d_op = &xattr_lookup_poison_ops;
1316                         reiserfs_mark_inode_private(dentry->d_inode);
1317                         REISERFS_SB(s)->priv_root = dentry;
1318                 } else if (!(mount_flags & MS_RDONLY)) {        /* xattrs are unavailable */
1319                         /* If we're read-only it just means that the dir hasn't been
1320                          * created. Not an error -- just no xattrs on the fs. We'll
1321                          * check again if we go read-write */
1322                         reiserfs_warning(s, "xattrs/ACLs enabled and couldn't "
1323                                          "find/create .reiserfs_priv. Failing mount.");
1324                         err = -EOPNOTSUPP;
1325                 }
1326         }
1327
1328       error:
1329         /* This is only nonzero if there was an error initializing the xattr
1330          * directory or if there is a condition where we don't support them. */
1331         if (err) {
1332                 clear_bit(REISERFS_XATTRS, &(REISERFS_SB(s)->s_mount_opt));
1333                 clear_bit(REISERFS_XATTRS_USER, &(REISERFS_SB(s)->s_mount_opt));
1334                 clear_bit(REISERFS_POSIXACL, &(REISERFS_SB(s)->s_mount_opt));
1335         }
1336
1337         /* The super_block MS_POSIXACL must mirror the (no)acl mount option. */
1338         s->s_flags = s->s_flags & ~MS_POSIXACL;
1339         if (reiserfs_posixacl(s))
1340                 s->s_flags |= MS_POSIXACL;
1341
1342         return err;
1343 }
1344
1345 static int
1346 __reiserfs_permission(struct inode *inode, int mask, struct nameidata *nd,
1347                       int need_lock)
1348 {
1349         umode_t mode = inode->i_mode;
1350
1351         if (mask & MAY_WRITE) {
1352                 /*
1353                  * Nobody gets write access to a read-only fs.
1354                  */
1355                 if (IS_RDONLY(inode) &&
1356                     (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode)))
1357                         return -EROFS;
1358
1359                 /*
1360                  * Nobody gets write access to an immutable file.
1361                  */
1362                 if (IS_IMMUTABLE(inode))
1363                         return -EACCES;
1364         }
1365
1366         /* We don't do permission checks on the internal objects.
1367          * Permissions are determined by the "owning" object. */
1368         if (is_reiserfs_priv_object(inode))
1369                 return 0;
1370
1371         if (current->fsuid == inode->i_uid) {
1372                 mode >>= 6;
1373 #ifdef CONFIG_REISERFS_FS_POSIX_ACL
1374         } else if (reiserfs_posixacl(inode->i_sb) &&
1375                    get_inode_sd_version(inode) != STAT_DATA_V1) {
1376                 struct posix_acl *acl;
1377
1378                 /* ACL can't contain additional permissions if
1379                    the ACL_MASK entry is 0 */
1380                 if (!(mode & S_IRWXG))
1381                         goto check_groups;
1382
1383                 if (need_lock) {
1384                         reiserfs_read_lock_xattr_i(inode);
1385                         reiserfs_read_lock_xattrs(inode->i_sb);
1386                 }
1387                 acl = reiserfs_get_acl(inode, ACL_TYPE_ACCESS);
1388                 if (need_lock) {
1389                         reiserfs_read_unlock_xattrs(inode->i_sb);
1390                         reiserfs_read_unlock_xattr_i(inode);
1391                 }
1392                 if (IS_ERR(acl)) {
1393                         if (PTR_ERR(acl) == -ENODATA)
1394                                 goto check_groups;
1395                         return PTR_ERR(acl);
1396                 }
1397
1398                 if (acl) {
1399                         int err = posix_acl_permission(inode, acl, mask);
1400                         posix_acl_release(acl);
1401                         if (err == -EACCES) {
1402                                 goto check_capabilities;
1403                         }
1404                         return err;
1405                 } else {
1406                         goto check_groups;
1407                 }
1408 #endif
1409         } else {
1410               check_groups:
1411                 if (in_group_p(inode->i_gid))
1412                         mode >>= 3;
1413         }
1414
1415         /*
1416          * If the DACs are ok we don't need any capability check.
1417          */
1418         if (((mode & mask & (MAY_READ | MAY_WRITE | MAY_EXEC)) == mask))
1419                 return 0;
1420
1421       check_capabilities:
1422         /*
1423          * Read/write DACs are always overridable.
1424          * Executable DACs are overridable if at least one exec bit is set.
1425          */
1426         if (!(mask & MAY_EXEC) ||
1427             (inode->i_mode & S_IXUGO) || S_ISDIR(inode->i_mode))
1428                 if (capable(CAP_DAC_OVERRIDE))
1429                         return 0;
1430
1431         /*
1432          * Searching includes executable on directories, else just read.
1433          */
1434         if (mask == MAY_READ || (S_ISDIR(inode->i_mode) && !(mask & MAY_WRITE)))
1435                 if (capable(CAP_DAC_READ_SEARCH))
1436                         return 0;
1437
1438         return -EACCES;
1439 }
1440
1441 int reiserfs_permission(struct inode *inode, int mask, struct nameidata *nd)
1442 {
1443         return __reiserfs_permission(inode, mask, nd, 1);
1444 }
1445
1446 int
1447 reiserfs_permission_locked(struct inode *inode, int mask, struct nameidata *nd)
1448 {
1449         return __reiserfs_permission(inode, mask, nd, 0);
1450 }