fs/reiserfs/xattr.c

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This source file includes following definitions.
xattr_create
xattr_mkdir
xattr_unlink
xattr_rmdir
open_xa_root
open_xa_dir
fill_with_dentries
cleanup_dentry_buf
reiserfs_for_each_xattr
delete_one_xattr
chown_one_xattr
reiserfs_delete_xattrs
reiserfs_chown_xattrs
xattr_lookup
reiserfs_put_page
reiserfs_get_page
xattr_hash
update_ctime
lookup_and_delete_xattr
reiserfs_xattr_set_handle
reiserfs_xattr_set
reiserfs_xattr_get
find_xattr_handler_prefix
listxattr_filler
reiserfs_listxattr
create_privroot
reiserfs_xattr_register_handlers
reiserfs_xattr_unregister_handlers
create_privroot
xattr_mount_check
reiserfs_permission
xattr_hide_revalidate
reiserfs_lookup_privroot
reiserfs_xattr_init
   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * linux/fs/reiserfs/xattr.c
   4  *
   5  * Copyright (c) 2002 by Jeff Mahoney, <jeffm@suse.com>
   6  *
   7  */
   8 
   9 /*
  10  * In order to implement EA/ACLs in a clean, backwards compatible manner,
  11  * they are implemented as files in a "private" directory.
  12  * Each EA is in it's own file, with the directory layout like so (/ is assumed
  13  * to be relative to fs root). Inside the /.reiserfs_priv/xattrs directory,
  14  * directories named using the capital-hex form of the objectid and
  15  * generation number are used. Inside each directory are individual files
  16  * named with the name of the extended attribute.
  17  *
  18  * So, for objectid 12648430, we could have:
  19  * /.reiserfs_priv/xattrs/C0FFEE.0/system.posix_acl_access
  20  * /.reiserfs_priv/xattrs/C0FFEE.0/system.posix_acl_default
  21  * /.reiserfs_priv/xattrs/C0FFEE.0/user.Content-Type
  22  * .. or similar.
  23  *
  24  * The file contents are the text of the EA. The size is known based on the
  25  * stat data describing the file.
  26  *
  27  * In the case of system.posix_acl_access and system.posix_acl_default, since
  28  * these are special cases for filesystem ACLs, they are interpreted by the
  29  * kernel, in addition, they are negatively and positively cached and attached
  30  * to the inode so that unnecessary lookups are avoided.
  31  *
  32  * Locking works like so:
  33  * Directory components (xattr root, xattr dir) are protectd by their i_mutex.
  34  * The xattrs themselves are protected by the xattr_sem.
  35  */
  36 
  37 #include "reiserfs.h"
  38 #include <linux/capability.h>
  39 #include <linux/dcache.h>
  40 #include <linux/namei.h>
  41 #include <linux/errno.h>
  42 #include <linux/gfp.h>
  43 #include <linux/fs.h>
  44 #include <linux/file.h>
  45 #include <linux/pagemap.h>
  46 #include <linux/xattr.h>
  47 #include "xattr.h"
  48 #include "acl.h"
  49 #include <linux/uaccess.h>
  50 #include <net/checksum.h>
  51 #include <linux/stat.h>
  52 #include <linux/quotaops.h>
  53 #include <linux/security.h>
  54 #include <linux/posix_acl_xattr.h>
  55 
  56 #define PRIVROOT_NAME ".reiserfs_priv"
  57 #define XAROOT_NAME   "xattrs"
  58 
  59 
  60 /*
  61  * Helpers for inode ops. We do this so that we don't have all the VFS
  62  * overhead and also for proper i_mutex annotation.
  63  * dir->i_mutex must be held for all of them.
  64  */
  65 #ifdef CONFIG_REISERFS_FS_XATTR
  66 static int xattr_create(struct inode *dir, struct dentry *dentry, int mode)
  67 {
  68         BUG_ON(!inode_is_locked(dir));
  69         return dir->i_op->create(dir, dentry, mode, true);
  70 }
  71 #endif
  72 
  73 static int xattr_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
  74 {
  75         BUG_ON(!inode_is_locked(dir));
  76         return dir->i_op->mkdir(dir, dentry, mode);
  77 }
  78 
  79 /*
  80  * We use I_MUTEX_CHILD here to silence lockdep. It's safe because xattr
  81  * mutation ops aren't called during rename or splace, which are the
  82  * only other users of I_MUTEX_CHILD. It violates the ordering, but that's
  83  * better than allocating another subclass just for this code.
  84  */
  85 static int xattr_unlink(struct inode *dir, struct dentry *dentry)
  86 {
  87         int error;
  88 
  89         BUG_ON(!inode_is_locked(dir));
  90 
  91         inode_lock_nested(d_inode(dentry), I_MUTEX_CHILD);
  92         error = dir->i_op->unlink(dir, dentry);
  93         inode_unlock(d_inode(dentry));
  94 
  95         if (!error)
  96                 d_delete(dentry);
  97         return error;
  98 }
  99 
 100 static int xattr_rmdir(struct inode *dir, struct dentry *dentry)
 101 {
 102         int error;
 103 
 104         BUG_ON(!inode_is_locked(dir));
 105 
 106         inode_lock_nested(d_inode(dentry), I_MUTEX_CHILD);
 107         error = dir->i_op->rmdir(dir, dentry);
 108         if (!error)
 109                 d_inode(dentry)->i_flags |= S_DEAD;
 110         inode_unlock(d_inode(dentry));
 111         if (!error)
 112                 d_delete(dentry);
 113 
 114         return error;
 115 }
 116 
 117 #define xattr_may_create(flags) (!flags || flags & XATTR_CREATE)
 118 
 119 static struct dentry *open_xa_root(struct super_block *sb, int flags)
 120 {
 121         struct dentry *privroot = REISERFS_SB(sb)->priv_root;
 122         struct dentry *xaroot;
 123 
 124         if (d_really_is_negative(privroot))
 125                 return ERR_PTR(-EOPNOTSUPP);
 126 
 127         inode_lock_nested(d_inode(privroot), I_MUTEX_XATTR);
 128 
 129         xaroot = dget(REISERFS_SB(sb)->xattr_root);
 130         if (!xaroot)
 131                 xaroot = ERR_PTR(-EOPNOTSUPP);
 132         else if (d_really_is_negative(xaroot)) {
 133                 int err = -ENODATA;
 134 
 135                 if (xattr_may_create(flags))
 136                         err = xattr_mkdir(d_inode(privroot), xaroot, 0700);
 137                 if (err) {
 138                         dput(xaroot);
 139                         xaroot = ERR_PTR(err);
 140                 }
 141         }
 142 
 143         inode_unlock(d_inode(privroot));
 144         return xaroot;
 145 }
 146 
 147 static struct dentry *open_xa_dir(const struct inode *inode, int flags)
 148 {
 149         struct dentry *xaroot, *xadir;
 150         char namebuf[17];
 151 
 152         xaroot = open_xa_root(inode->i_sb, flags);
 153         if (IS_ERR(xaroot))
 154                 return xaroot;
 155 
 156         snprintf(namebuf, sizeof(namebuf), "%X.%X",
 157                  le32_to_cpu(INODE_PKEY(inode)->k_objectid),
 158                  inode->i_generation);
 159 
 160         inode_lock_nested(d_inode(xaroot), I_MUTEX_XATTR);
 161 
 162         xadir = lookup_one_len(namebuf, xaroot, strlen(namebuf));
 163         if (!IS_ERR(xadir) && d_really_is_negative(xadir)) {
 164                 int err = -ENODATA;
 165 
 166                 if (xattr_may_create(flags))
 167                         err = xattr_mkdir(d_inode(xaroot), xadir, 0700);
 168                 if (err) {
 169                         dput(xadir);
 170                         xadir = ERR_PTR(err);
 171                 }
 172         }
 173 
 174         inode_unlock(d_inode(xaroot));
 175         dput(xaroot);
 176         return xadir;
 177 }
 178 
 179 /*
 180  * The following are side effects of other operations that aren't explicitly
 181  * modifying extended attributes. This includes operations such as permissions
 182  * or ownership changes, object deletions, etc.
 183  */
 184 struct reiserfs_dentry_buf {
 185         struct dir_context ctx;
 186         struct dentry *xadir;
 187         int count;
 188         int err;
 189         struct dentry *dentries[8];
 190 };
 191 
 192 static int
 193 fill_with_dentries(struct dir_context *ctx, const char *name, int namelen,
 194                    loff_t offset, u64 ino, unsigned int d_type)
 195 {
 196         struct reiserfs_dentry_buf *dbuf =
 197                 container_of(ctx, struct reiserfs_dentry_buf, ctx);
 198         struct dentry *dentry;
 199 
 200         WARN_ON_ONCE(!inode_is_locked(d_inode(dbuf->xadir)));
 201 
 202         if (dbuf->count == ARRAY_SIZE(dbuf->dentries))
 203                 return -ENOSPC;
 204 
 205         if (name[0] == '.' && (namelen < 2 ||
 206                                (namelen == 2 && name[1] == '.')))
 207                 return 0;
 208 
 209         dentry = lookup_one_len(name, dbuf->xadir, namelen);
 210         if (IS_ERR(dentry)) {
 211                 dbuf->err = PTR_ERR(dentry);
 212                 return PTR_ERR(dentry);
 213         } else if (d_really_is_negative(dentry)) {
 214                 /* A directory entry exists, but no file? */
 215                 reiserfs_error(dentry->d_sb, "xattr-20003",
 216                                "Corrupted directory: xattr %pd listed but "
 217                                "not found for file %pd.\n",
 218                                dentry, dbuf->xadir);
 219                 dput(dentry);
 220                 dbuf->err = -EIO;
 221                 return -EIO;
 222         }
 223 
 224         dbuf->dentries[dbuf->count++] = dentry;
 225         return 0;
 226 }
 227 
 228 static void
 229 cleanup_dentry_buf(struct reiserfs_dentry_buf *buf)
 230 {
 231         int i;
 232 
 233         for (i = 0; i < buf->count; i++)
 234                 if (buf->dentries[i])
 235                         dput(buf->dentries[i]);
 236 }
 237 
 238 static int reiserfs_for_each_xattr(struct inode *inode,
 239                                    int (*action)(struct dentry *, void *),
 240                                    void *data)
 241 {
 242         struct dentry *dir;
 243         int i, err = 0;
 244         struct reiserfs_dentry_buf buf = {
 245                 .ctx.actor = fill_with_dentries,
 246         };
 247 
 248         /* Skip out, an xattr has no xattrs associated with it */
 249         if (IS_PRIVATE(inode) || get_inode_sd_version(inode) == STAT_DATA_V1)
 250                 return 0;
 251 
 252         dir = open_xa_dir(inode, XATTR_REPLACE);
 253         if (IS_ERR(dir)) {
 254                 err = PTR_ERR(dir);
 255                 goto out;
 256         } else if (d_really_is_negative(dir)) {
 257                 err = 0;
 258                 goto out_dir;
 259         }
 260 
 261         inode_lock_nested(d_inode(dir), I_MUTEX_XATTR);
 262 
 263         buf.xadir = dir;
 264         while (1) {
 265                 err = reiserfs_readdir_inode(d_inode(dir), &buf.ctx);
 266                 if (err)
 267                         break;
 268                 if (buf.err) {
 269                         err = buf.err;
 270                         break;
 271                 }
 272                 if (!buf.count)
 273                         break;
 274                 for (i = 0; !err && i < buf.count && buf.dentries[i]; i++) {
 275                         struct dentry *dentry = buf.dentries[i];
 276 
 277                         if (!d_is_dir(dentry))
 278                                 err = action(dentry, data);
 279 
 280                         dput(dentry);
 281                         buf.dentries[i] = NULL;
 282                 }
 283                 if (err)
 284                         break;
 285                 buf.count = 0;
 286         }
 287         inode_unlock(d_inode(dir));
 288 
 289         cleanup_dentry_buf(&buf);
 290 
 291         if (!err) {
 292                 /*
 293                  * We start a transaction here to avoid a ABBA situation
 294                  * between the xattr root's i_mutex and the journal lock.
 295                  * This doesn't incur much additional overhead since the
 296                  * new transaction will just nest inside the
 297                  * outer transaction.
 298                  */
 299                 int blocks = JOURNAL_PER_BALANCE_CNT * 2 + 2 +
 300                              4 * REISERFS_QUOTA_TRANS_BLOCKS(inode->i_sb);
 301                 struct reiserfs_transaction_handle th;
 302 
 303                 reiserfs_write_lock(inode->i_sb);
 304                 err = journal_begin(&th, inode->i_sb, blocks);
 305                 reiserfs_write_unlock(inode->i_sb);
 306                 if (!err) {
 307                         int jerror;
 308 
 309                         inode_lock_nested(d_inode(dir->d_parent),
 310                                           I_MUTEX_XATTR);
 311                         err = action(dir, data);
 312                         reiserfs_write_lock(inode->i_sb);
 313                         jerror = journal_end(&th);
 314                         reiserfs_write_unlock(inode->i_sb);
 315                         inode_unlock(d_inode(dir->d_parent));
 316                         err = jerror ?: err;
 317                 }
 318         }
 319 out_dir:
 320         dput(dir);
 321 out:
 322         /*
 323          * -ENODATA: this object doesn't have any xattrs
 324          * -EOPNOTSUPP: this file system doesn't have xattrs enabled on disk.
 325          * Neither are errors
 326          */
 327         if (err == -ENODATA || err == -EOPNOTSUPP)
 328                 err = 0;
 329         return err;
 330 }
 331 
 332 static int delete_one_xattr(struct dentry *dentry, void *data)
 333 {
 334         struct inode *dir = d_inode(dentry->d_parent);
 335 
 336         /* This is the xattr dir, handle specially. */
 337         if (d_is_dir(dentry))
 338                 return xattr_rmdir(dir, dentry);
 339 
 340         return xattr_unlink(dir, dentry);
 341 }
 342 
 343 static int chown_one_xattr(struct dentry *dentry, void *data)
 344 {
 345         struct iattr *attrs = data;
 346         int ia_valid = attrs->ia_valid;
 347         int err;
 348 
 349         /*
 350          * We only want the ownership bits. Otherwise, we'll do
 351          * things like change a directory to a regular file if
 352          * ATTR_MODE is set.
 353          */
 354         attrs->ia_valid &= (ATTR_UID|ATTR_GID);
 355         err = reiserfs_setattr(dentry, attrs);
 356         attrs->ia_valid = ia_valid;
 357 
 358         return err;
 359 }
 360 
 361 /* No i_mutex, but the inode is unconnected. */
 362 int reiserfs_delete_xattrs(struct inode *inode)
 363 {
 364         int err = reiserfs_for_each_xattr(inode, delete_one_xattr, NULL);
 365 
 366         if (err)
 367                 reiserfs_warning(inode->i_sb, "jdm-20004",
 368                                  "Couldn't delete all xattrs (%d)\n", err);
 369         return err;
 370 }
 371 
 372 /* inode->i_mutex: down */
 373 int reiserfs_chown_xattrs(struct inode *inode, struct iattr *attrs)
 374 {
 375         int err = reiserfs_for_each_xattr(inode, chown_one_xattr, attrs);
 376 
 377         if (err)
 378                 reiserfs_warning(inode->i_sb, "jdm-20007",
 379                                  "Couldn't chown all xattrs (%d)\n", err);
 380         return err;
 381 }
 382 
 383 #ifdef CONFIG_REISERFS_FS_XATTR
 384 /*
 385  * Returns a dentry corresponding to a specific extended attribute file
 386  * for the inode. If flags allow, the file is created. Otherwise, a
 387  * valid or negative dentry, or an error is returned.
 388  */
 389 static struct dentry *xattr_lookup(struct inode *inode, const char *name,
 390                                     int flags)
 391 {
 392         struct dentry *xadir, *xafile;
 393         int err = 0;
 394 
 395         xadir = open_xa_dir(inode, flags);
 396         if (IS_ERR(xadir))
 397                 return ERR_CAST(xadir);
 398 
 399         inode_lock_nested(d_inode(xadir), I_MUTEX_XATTR);
 400         xafile = lookup_one_len(name, xadir, strlen(name));
 401         if (IS_ERR(xafile)) {
 402                 err = PTR_ERR(xafile);
 403                 goto out;
 404         }
 405 
 406         if (d_really_is_positive(xafile) && (flags & XATTR_CREATE))
 407                 err = -EEXIST;
 408 
 409         if (d_really_is_negative(xafile)) {
 410                 err = -ENODATA;
 411                 if (xattr_may_create(flags))
 412                         err = xattr_create(d_inode(xadir), xafile,
 413                                               0700|S_IFREG);
 414         }
 415 
 416         if (err)
 417                 dput(xafile);
 418 out:
 419         inode_unlock(d_inode(xadir));
 420         dput(xadir);
 421         if (err)
 422                 return ERR_PTR(err);
 423         return xafile;
 424 }
 425 
 426 /* Internal operations on file data */
 427 static inline void reiserfs_put_page(struct page *page)
 428 {
 429         kunmap(page);
 430         put_page(page);
 431 }
 432 
 433 static struct page *reiserfs_get_page(struct inode *dir, size_t n)
 434 {
 435         struct address_space *mapping = dir->i_mapping;
 436         struct page *page;
 437         /*
 438          * We can deadlock if we try to free dentries,
 439          * and an unlink/rmdir has just occurred - GFP_NOFS avoids this
 440          */
 441         mapping_set_gfp_mask(mapping, GFP_NOFS);
 442         page = read_mapping_page(mapping, n >> PAGE_SHIFT, NULL);
 443         if (!IS_ERR(page)) {
 444                 kmap(page);
 445                 if (PageError(page))
 446                         goto fail;
 447         }
 448         return page;
 449 
 450 fail:
 451         reiserfs_put_page(page);
 452         return ERR_PTR(-EIO);
 453 }
 454 
 455 static inline __u32 xattr_hash(const char *msg, int len)
 456 {
 457         /*
 458          * csum_partial() gives different results for little-endian and
 459          * big endian hosts. Images created on little-endian hosts and
 460          * mounted on big-endian hosts(and vice versa) will see csum mismatches
 461          * when trying to fetch xattrs. Treating the hash as __wsum_t would
 462          * lower the frequency of mismatch.  This is an endianness bug in
 463          * reiserfs.  The return statement would result in a sparse warning. Do
 464          * not fix the sparse warning so as to not hide a reminder of the bug.
 465          */
 466         return csum_partial(msg, len, 0);
 467 }
 468 
 469 int reiserfs_commit_write(struct file *f, struct page *page,
 470                           unsigned from, unsigned to);
 471 
 472 static void update_ctime(struct inode *inode)
 473 {
 474         struct timespec64 now = current_time(inode);
 475 
 476         if (inode_unhashed(inode) || !inode->i_nlink ||
 477             timespec64_equal(&inode->i_ctime, &now))
 478                 return;
 479 
 480         inode->i_ctime = current_time(inode);
 481         mark_inode_dirty(inode);
 482 }
 483 
 484 static int lookup_and_delete_xattr(struct inode *inode, const char *name)
 485 {
 486         int err = 0;
 487         struct dentry *dentry, *xadir;
 488 
 489         xadir = open_xa_dir(inode, XATTR_REPLACE);
 490         if (IS_ERR(xadir))
 491                 return PTR_ERR(xadir);
 492 
 493         inode_lock_nested(d_inode(xadir), I_MUTEX_XATTR);
 494         dentry = lookup_one_len(name, xadir, strlen(name));
 495         if (IS_ERR(dentry)) {
 496                 err = PTR_ERR(dentry);
 497                 goto out_dput;
 498         }
 499 
 500         if (d_really_is_positive(dentry)) {
 501                 err = xattr_unlink(d_inode(xadir), dentry);
 502                 update_ctime(inode);
 503         }
 504 
 505         dput(dentry);
 506 out_dput:
 507         inode_unlock(d_inode(xadir));
 508         dput(xadir);
 509         return err;
 510 }
 511 
 512 
 513 /* Generic extended attribute operations that can be used by xa plugins */
 514 
 515 /*
 516  * inode->i_mutex: down
 517  */
 518 int
 519 reiserfs_xattr_set_handle(struct reiserfs_transaction_handle *th,
 520                           struct inode *inode, const char *name,
 521                           const void *buffer, size_t buffer_size, int flags)
 522 {
 523         int err = 0;
 524         struct dentry *dentry;
 525         struct page *page;
 526         char *data;
 527         size_t file_pos = 0;
 528         size_t buffer_pos = 0;
 529         size_t new_size;
 530         __u32 xahash = 0;
 531 
 532         if (get_inode_sd_version(inode) == STAT_DATA_V1)
 533                 return -EOPNOTSUPP;
 534 
 535         if (!buffer) {
 536                 err = lookup_and_delete_xattr(inode, name);
 537                 return err;
 538         }
 539 
 540         dentry = xattr_lookup(inode, name, flags);
 541         if (IS_ERR(dentry))
 542                 return PTR_ERR(dentry);
 543 
 544         down_write(&REISERFS_I(inode)->i_xattr_sem);
 545 
 546         xahash = xattr_hash(buffer, buffer_size);
 547         while (buffer_pos < buffer_size || buffer_pos == 0) {
 548                 size_t chunk;
 549                 size_t skip = 0;
 550                 size_t page_offset = (file_pos & (PAGE_SIZE - 1));
 551 
 552                 if (buffer_size - buffer_pos > PAGE_SIZE)
 553                         chunk = PAGE_SIZE;
 554                 else
 555                         chunk = buffer_size - buffer_pos;
 556 
 557                 page = reiserfs_get_page(d_inode(dentry), file_pos);
 558                 if (IS_ERR(page)) {
 559                         err = PTR_ERR(page);
 560                         goto out_unlock;
 561                 }
 562 
 563                 lock_page(page);
 564                 data = page_address(page);
 565 
 566                 if (file_pos == 0) {
 567                         struct reiserfs_xattr_header *rxh;
 568 
 569                         skip = file_pos = sizeof(struct reiserfs_xattr_header);
 570                         if (chunk + skip > PAGE_SIZE)
 571                                 chunk = PAGE_SIZE - skip;
 572                         rxh = (struct reiserfs_xattr_header *)data;
 573                         rxh->h_magic = cpu_to_le32(REISERFS_XATTR_MAGIC);
 574                         rxh->h_hash = cpu_to_le32(xahash);
 575                 }
 576 
 577                 reiserfs_write_lock(inode->i_sb);
 578                 err = __reiserfs_write_begin(page, page_offset, chunk + skip);
 579                 if (!err) {
 580                         if (buffer)
 581                                 memcpy(data + skip, buffer + buffer_pos, chunk);
 582                         err = reiserfs_commit_write(NULL, page, page_offset,
 583                                                     page_offset + chunk +
 584                                                     skip);
 585                 }
 586                 reiserfs_write_unlock(inode->i_sb);
 587                 unlock_page(page);
 588                 reiserfs_put_page(page);
 589                 buffer_pos += chunk;
 590                 file_pos += chunk;
 591                 skip = 0;
 592                 if (err || buffer_size == 0 || !buffer)
 593                         break;
 594         }
 595 
 596         new_size = buffer_size + sizeof(struct reiserfs_xattr_header);
 597         if (!err && new_size < i_size_read(d_inode(dentry))) {
 598                 struct iattr newattrs = {
 599                         .ia_ctime = current_time(inode),
 600                         .ia_size = new_size,
 601                         .ia_valid = ATTR_SIZE | ATTR_CTIME,
 602                 };
 603 
 604                 inode_lock_nested(d_inode(dentry), I_MUTEX_XATTR);
 605                 inode_dio_wait(d_inode(dentry));
 606 
 607                 err = reiserfs_setattr(dentry, &newattrs);
 608                 inode_unlock(d_inode(dentry));
 609         } else
 610                 update_ctime(inode);
 611 out_unlock:
 612         up_write(&REISERFS_I(inode)->i_xattr_sem);
 613         dput(dentry);
 614         return err;
 615 }
 616 
 617 /* We need to start a transaction to maintain lock ordering */
 618 int reiserfs_xattr_set(struct inode *inode, const char *name,
 619                        const void *buffer, size_t buffer_size, int flags)
 620 {
 621 
 622         struct reiserfs_transaction_handle th;
 623         int error, error2;
 624         size_t jbegin_count = reiserfs_xattr_nblocks(inode, buffer_size);
 625 
 626         /* Check before we start a transaction and then do nothing. */
 627         if (!d_really_is_positive(REISERFS_SB(inode->i_sb)->priv_root))
 628                 return -EOPNOTSUPP;
 629 
 630         if (!(flags & XATTR_REPLACE))
 631                 jbegin_count += reiserfs_xattr_jcreate_nblocks(inode);
 632 
 633         reiserfs_write_lock(inode->i_sb);
 634         error = journal_begin(&th, inode->i_sb, jbegin_count);
 635         reiserfs_write_unlock(inode->i_sb);
 636         if (error) {
 637                 return error;
 638         }
 639 
 640         error = reiserfs_xattr_set_handle(&th, inode, name,
 641                                           buffer, buffer_size, flags);
 642 
 643         reiserfs_write_lock(inode->i_sb);
 644         error2 = journal_end(&th);
 645         reiserfs_write_unlock(inode->i_sb);
 646         if (error == 0)
 647                 error = error2;
 648 
 649         return error;
 650 }
 651 
 652 /*
 653  * inode->i_mutex: down
 654  */
 655 int
 656 reiserfs_xattr_get(struct inode *inode, const char *name, void *buffer,
 657                    size_t buffer_size)
 658 {
 659         ssize_t err = 0;
 660         struct dentry *dentry;
 661         size_t isize;
 662         size_t file_pos = 0;
 663         size_t buffer_pos = 0;
 664         struct page *page;
 665         __u32 hash = 0;
 666 
 667         if (name == NULL)
 668                 return -EINVAL;
 669 
 670         /*
 671          * We can't have xattrs attached to v1 items since they don't have
 672          * generation numbers
 673          */
 674         if (get_inode_sd_version(inode) == STAT_DATA_V1)
 675                 return -EOPNOTSUPP;
 676 
 677         dentry = xattr_lookup(inode, name, XATTR_REPLACE);
 678         if (IS_ERR(dentry)) {
 679                 err = PTR_ERR(dentry);
 680                 goto out;
 681         }
 682 
 683         down_read(&REISERFS_I(inode)->i_xattr_sem);
 684 
 685         isize = i_size_read(d_inode(dentry));
 686 
 687         /* Just return the size needed */
 688         if (buffer == NULL) {
 689                 err = isize - sizeof(struct reiserfs_xattr_header);
 690                 goto out_unlock;
 691         }
 692 
 693         if (buffer_size < isize - sizeof(struct reiserfs_xattr_header)) {
 694                 err = -ERANGE;
 695                 goto out_unlock;
 696         }
 697 
 698         while (file_pos < isize) {
 699                 size_t chunk;
 700                 char *data;
 701                 size_t skip = 0;
 702 
 703                 if (isize - file_pos > PAGE_SIZE)
 704                         chunk = PAGE_SIZE;
 705                 else
 706                         chunk = isize - file_pos;
 707 
 708                 page = reiserfs_get_page(d_inode(dentry), file_pos);
 709                 if (IS_ERR(page)) {
 710                         err = PTR_ERR(page);
 711                         goto out_unlock;
 712                 }
 713 
 714                 lock_page(page);
 715                 data = page_address(page);
 716                 if (file_pos == 0) {
 717                         struct reiserfs_xattr_header *rxh =
 718                             (struct reiserfs_xattr_header *)data;
 719                         skip = file_pos = sizeof(struct reiserfs_xattr_header);
 720                         chunk -= skip;
 721                         /* Magic doesn't match up.. */
 722                         if (rxh->h_magic != cpu_to_le32(REISERFS_XATTR_MAGIC)) {
 723                                 unlock_page(page);
 724                                 reiserfs_put_page(page);
 725                                 reiserfs_warning(inode->i_sb, "jdm-20001",
 726                                                  "Invalid magic for xattr (%s) "
 727                                                  "associated with %k", name,
 728                                                  INODE_PKEY(inode));
 729                                 err = -EIO;
 730                                 goto out_unlock;
 731                         }
 732                         hash = le32_to_cpu(rxh->h_hash);
 733                 }
 734                 memcpy(buffer + buffer_pos, data + skip, chunk);
 735                 unlock_page(page);
 736                 reiserfs_put_page(page);
 737                 file_pos += chunk;
 738                 buffer_pos += chunk;
 739                 skip = 0;
 740         }
 741         err = isize - sizeof(struct reiserfs_xattr_header);
 742 
 743         if (xattr_hash(buffer, isize - sizeof(struct reiserfs_xattr_header)) !=
 744             hash) {
 745                 reiserfs_warning(inode->i_sb, "jdm-20002",
 746                                  "Invalid hash for xattr (%s) associated "
 747                                  "with %k", name, INODE_PKEY(inode));
 748                 err = -EIO;
 749         }
 750 
 751 out_unlock:
 752         up_read(&REISERFS_I(inode)->i_xattr_sem);
 753         dput(dentry);
 754 
 755 out:
 756         return err;
 757 }
 758 
 759 /*
 760  * In order to implement different sets of xattr operations for each xattr
 761  * prefix with the generic xattr API, a filesystem should create a
 762  * null-terminated array of struct xattr_handler (one for each prefix) and
 763  * hang a pointer to it off of the s_xattr field of the superblock.
 764  *
 765  * The generic_fooxattr() functions will use this list to dispatch xattr
 766  * operations to the correct xattr_handler.
 767  */
 768 #define for_each_xattr_handler(handlers, handler)               \
 769                 for ((handler) = *(handlers)++;                 \
 770                         (handler) != NULL;                      \
 771                         (handler) = *(handlers)++)
 772 
 773 /* This is the implementation for the xattr plugin infrastructure */
 774 static inline const struct xattr_handler *
 775 find_xattr_handler_prefix(const struct xattr_handler **handlers,
 776                            const char *name)
 777 {
 778         const struct xattr_handler *xah;
 779 
 780         if (!handlers)
 781                 return NULL;
 782 
 783         for_each_xattr_handler(handlers, xah) {
 784                 const char *prefix = xattr_prefix(xah);
 785                 if (strncmp(prefix, name, strlen(prefix)) == 0)
 786                         break;
 787         }
 788 
 789         return xah;
 790 }
 791 
 792 struct listxattr_buf {
 793         struct dir_context ctx;
 794         size_t size;
 795         size_t pos;
 796         char *buf;
 797         struct dentry *dentry;
 798 };
 799 
 800 static int listxattr_filler(struct dir_context *ctx, const char *name,
 801                             int namelen, loff_t offset, u64 ino,
 802                             unsigned int d_type)
 803 {
 804         struct listxattr_buf *b =
 805                 container_of(ctx, struct listxattr_buf, ctx);
 806         size_t size;
 807 
 808         if (name[0] != '.' ||
 809             (namelen != 1 && (name[1] != '.' || namelen != 2))) {
 810                 const struct xattr_handler *handler;
 811 
 812                 handler = find_xattr_handler_prefix(b->dentry->d_sb->s_xattr,
 813                                                     name);
 814                 if (!handler /* Unsupported xattr name */ ||
 815                     (handler->list && !handler->list(b->dentry)))
 816                         return 0;
 817                 size = namelen + 1;
 818                 if (b->buf) {
 819                         if (b->pos + size > b->size) {
 820                                 b->pos = -ERANGE;
 821                                 return -ERANGE;
 822                         }
 823                         memcpy(b->buf + b->pos, name, namelen);
 824                         b->buf[b->pos + namelen] = 0;
 825                 }
 826                 b->pos += size;
 827         }
 828         return 0;
 829 }
 830 
 831 /*
 832  * Inode operation listxattr()
 833  *
 834  * We totally ignore the generic listxattr here because it would be stupid
 835  * not to. Since the xattrs are organized in a directory, we can just
 836  * readdir to find them.
 837  */
 838 ssize_t reiserfs_listxattr(struct dentry * dentry, char *buffer, size_t size)
 839 {
 840         struct dentry *dir;
 841         int err = 0;
 842         struct listxattr_buf buf = {
 843                 .ctx.actor = listxattr_filler,
 844                 .dentry = dentry,
 845                 .buf = buffer,
 846                 .size = buffer ? size : 0,
 847         };
 848 
 849         if (d_really_is_negative(dentry))
 850                 return -EINVAL;
 851 
 852         if (get_inode_sd_version(d_inode(dentry)) == STAT_DATA_V1)
 853                 return -EOPNOTSUPP;
 854 
 855         dir = open_xa_dir(d_inode(dentry), XATTR_REPLACE);
 856         if (IS_ERR(dir)) {
 857                 err = PTR_ERR(dir);
 858                 if (err == -ENODATA)
 859                         err = 0;  /* Not an error if there aren't any xattrs */
 860                 goto out;
 861         }
 862 
 863         inode_lock_nested(d_inode(dir), I_MUTEX_XATTR);
 864         err = reiserfs_readdir_inode(d_inode(dir), &buf.ctx);
 865         inode_unlock(d_inode(dir));
 866 
 867         if (!err)
 868                 err = buf.pos;
 869 
 870         dput(dir);
 871 out:
 872         return err;
 873 }
 874 
 875 static int create_privroot(struct dentry *dentry)
 876 {
 877         int err;
 878         struct inode *inode = d_inode(dentry->d_parent);
 879 
 880         WARN_ON_ONCE(!inode_is_locked(inode));
 881 
 882         err = xattr_mkdir(inode, dentry, 0700);
 883         if (err || d_really_is_negative(dentry)) {
 884                 reiserfs_warning(dentry->d_sb, "jdm-20006",
 885                                  "xattrs/ACLs enabled and couldn't "
 886                                  "find/create .reiserfs_priv. "
 887                                  "Failing mount.");
 888                 return -EOPNOTSUPP;
 889         }
 890 
 891         d_inode(dentry)->i_flags |= S_PRIVATE;
 892         d_inode(dentry)->i_opflags &= ~IOP_XATTR;
 893         reiserfs_info(dentry->d_sb, "Created %s - reserved for xattr "
 894                       "storage.\n", PRIVROOT_NAME);
 895 
 896         return 0;
 897 }
 898 
 899 #else
 900 int __init reiserfs_xattr_register_handlers(void) { return 0; }
 901 void reiserfs_xattr_unregister_handlers(void) {}
 902 static int create_privroot(struct dentry *dentry) { return 0; }
 903 #endif
 904 
 905 /* Actual operations that are exported to VFS-land */
 906 const struct xattr_handler *reiserfs_xattr_handlers[] = {
 907 #ifdef CONFIG_REISERFS_FS_XATTR
 908         &reiserfs_xattr_user_handler,
 909         &reiserfs_xattr_trusted_handler,
 910 #endif
 911 #ifdef CONFIG_REISERFS_FS_SECURITY
 912         &reiserfs_xattr_security_handler,
 913 #endif
 914 #ifdef CONFIG_REISERFS_FS_POSIX_ACL
 915         &posix_acl_access_xattr_handler,
 916         &posix_acl_default_xattr_handler,
 917 #endif
 918         NULL
 919 };
 920 
 921 static int xattr_mount_check(struct super_block *s)
 922 {
 923         /*
 924          * We need generation numbers to ensure that the oid mapping is correct
 925          * v3.5 filesystems don't have them.
 926          */
 927         if (old_format_only(s)) {
 928                 if (reiserfs_xattrs_optional(s)) {
 929                         /*
 930                          * Old format filesystem, but optional xattrs have
 931                          * been enabled. Error out.
 932                          */
 933                         reiserfs_warning(s, "jdm-2005",
 934                                          "xattrs/ACLs not supported "
 935                                          "on pre-v3.6 format filesystems. "
 936                                          "Failing mount.");
 937                         return -EOPNOTSUPP;
 938                 }
 939         }
 940 
 941         return 0;
 942 }
 943 
 944 int reiserfs_permission(struct inode *inode, int mask)
 945 {
 946         /*
 947          * We don't do permission checks on the internal objects.
 948          * Permissions are determined by the "owning" object.
 949          */
 950         if (IS_PRIVATE(inode))
 951                 return 0;
 952 
 953         return generic_permission(inode, mask);
 954 }
 955 
 956 static int xattr_hide_revalidate(struct dentry *dentry, unsigned int flags)
 957 {
 958         return -EPERM;
 959 }
 960 
 961 static const struct dentry_operations xattr_lookup_poison_ops = {
 962         .d_revalidate = xattr_hide_revalidate,
 963 };
 964 
 965 int reiserfs_lookup_privroot(struct super_block *s)
 966 {
 967         struct dentry *dentry;
 968         int err = 0;
 969 
 970         /* If we don't have the privroot located yet - go find it */
 971         inode_lock(d_inode(s->s_root));
 972         dentry = lookup_one_len(PRIVROOT_NAME, s->s_root,
 973                                 strlen(PRIVROOT_NAME));
 974         if (!IS_ERR(dentry)) {
 975                 REISERFS_SB(s)->priv_root = dentry;
 976                 d_set_d_op(dentry, &xattr_lookup_poison_ops);
 977                 if (d_really_is_positive(dentry)) {
 978                         d_inode(dentry)->i_flags |= S_PRIVATE;
 979                         d_inode(dentry)->i_opflags &= ~IOP_XATTR;
 980                 }
 981         } else
 982                 err = PTR_ERR(dentry);
 983         inode_unlock(d_inode(s->s_root));
 984 
 985         return err;
 986 }
 987 
 988 /*
 989  * We need to take a copy of the mount flags since things like
 990  * SB_RDONLY don't get set until *after* we're called.
 991  * mount_flags != mount_options
 992  */
 993 int reiserfs_xattr_init(struct super_block *s, int mount_flags)
 994 {
 995         int err = 0;
 996         struct dentry *privroot = REISERFS_SB(s)->priv_root;
 997 
 998         err = xattr_mount_check(s);
 999         if (err)
1000                 goto error;
1001 
1002         if (d_really_is_negative(privroot) && !(mount_flags & SB_RDONLY)) {
1003                 inode_lock(d_inode(s->s_root));
1004                 err = create_privroot(REISERFS_SB(s)->priv_root);
1005                 inode_unlock(d_inode(s->s_root));
1006         }
1007 
1008         if (d_really_is_positive(privroot)) {
1009                 inode_lock(d_inode(privroot));
1010                 if (!REISERFS_SB(s)->xattr_root) {
1011                         struct dentry *dentry;
1012 
1013                         dentry = lookup_one_len(XAROOT_NAME, privroot,
1014                                                 strlen(XAROOT_NAME));
1015                         if (!IS_ERR(dentry))
1016                                 REISERFS_SB(s)->xattr_root = dentry;
1017                         else
1018                                 err = PTR_ERR(dentry);
1019                 }
1020                 inode_unlock(d_inode(privroot));
1021         }
1022 
1023 error:
1024         if (err) {
1025                 clear_bit(REISERFS_XATTRS_USER, &REISERFS_SB(s)->s_mount_opt);
1026                 clear_bit(REISERFS_POSIXACL, &REISERFS_SB(s)->s_mount_opt);
1027         }
1028 
1029         /* The super_block SB_POSIXACL must mirror the (no)acl mount option. */
1030         if (reiserfs_posixacl(s))
1031                 s->s_flags |= SB_POSIXACL;
1032         else
1033                 s->s_flags &= ~SB_POSIXACL;
1034 
1035         return err;
1036 }
/* [<][>][^][v][top][bottom][index][help] */
root/fs/reiserfs/xattr.c

DEFINITIONS
