fs/ubifs/xattr.c

   1 /*
   2  * This file is part of UBIFS.
   3  *
   4  * Copyright (C) 2006-2008 Nokia Corporation.
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License version 2 as published by
   8  * the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  13  * more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along with
  16  * this program; if not, write to the Free Software Foundation, Inc., 51
  17  * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
  18  *
  19  * Authors: Artem Bityutskiy (Битюцкий Артём)
  20  *          Adrian Hunter
  21  */
  22
  23 /*
  24  * This file implements UBIFS extended attributes support.
  25  *
  26  * Extended attributes are implemented as regular inodes with attached data,
  27  * which limits extended attribute size to UBIFS block size (4KiB). Names of
  28  * extended attributes are described by extended attribute entries (xentries),
  29  * which are almost identical to directory entries, but have different key type.
  30  *
  31  * In other words, the situation with extended attributes is very similar to
  32  * directories. Indeed, any inode (but of course not xattr inodes) may have a
  33  * number of associated xentries, just like directory inodes have associated
  34  * directory entries. Extended attribute entries store the name of the extended
  35  * attribute, the host inode number, and the extended attribute inode number.
  36  * Similarly, direntries store the name, the parent and the target inode
  37  * numbers. Thus, most of the common UBIFS mechanisms may be re-used for
  38  * extended attributes.
  39  *
  40  * The number of extended attributes is not limited, but there is Linux
  41  * limitation on the maximum possible size of the list of all extended
  42  * attributes associated with an inode (%XATTR_LIST_MAX), so UBIFS makes sure
  43  * the sum of all extended attribute names of the inode does not exceed that
  44  * limit.
  45  *
  46  * Extended attributes are synchronous, which means they are written to the
  47  * flash media synchronously and there is no write-back for extended attribute
  48  * inodes. The extended attribute values are not stored in compressed form on
  49  * the media.
  50  *
  51  * Since extended attributes are represented by regular inodes, they are cached
  52  * in the VFS inode cache. The xentries are cached in the LNC cache (see
  53  * tnc.c).
  54  *
  55  * ACL support is not implemented.
  56  */
  57
  58 #include "ubifs.h"
  59 #include <linux/fs.h>
  60 #include <linux/slab.h>
  61 #include <linux/xattr.h>
  62
  63 /*
  64  * Limit the number of extended attributes per inode so that the total size
  65  * (@xattr_size) is guaranteeded to fit in an 'unsigned int'.
  66  */
  67 #define MAX_XATTRS_PER_INODE 65535
  68
  69 /*
  70  * Extended attribute type constants.
  71  *
  72  * USER_XATTR: user extended attribute ("user.*")
  73  * TRUSTED_XATTR: trusted extended attribute ("trusted.*)
  74  * SECURITY_XATTR: security extended attribute ("security.*")
  75  */
  76 enum {
  77         USER_XATTR,
  78         TRUSTED_XATTR,
  79         SECURITY_XATTR,
  80 };
  81
  82 static const struct inode_operations empty_iops;
  83 static const struct file_operations empty_fops;
  84
  85 /**
  86  * create_xattr - create an extended attribute.
  87  * @c: UBIFS file-system description object
  88  * @host: host inode
  89  * @nm: extended attribute name
  90  * @value: extended attribute value
  91  * @size: size of extended attribute value
  92  *
  93  * This is a helper function which creates an extended attribute of name @nm
  94  * and value @value for inode @host. The host inode is also updated on flash
  95  * because the ctime and extended attribute accounting data changes. This
  96  * function returns zero in case of success and a negative error code in case
  97  * of failure.
  98  */
  99 static int create_xattr(struct ubifs_info *c, struct inode *host,
 100                         const struct fscrypt_name *nm, const void *value, int size)
 101 {
 102         int err, names_len;
 103         struct inode *inode;
 104         struct ubifs_inode *ui, *host_ui = ubifs_inode(host);
 105         struct ubifs_budget_req req = { .new_ino = 1, .new_dent = 1,
 106                                 .new_ino_d = ALIGN(size, 8), .dirtied_ino = 1,
 107                                 .dirtied_ino_d = ALIGN(host_ui->data_len, 8) };
 108
 109         if (host_ui->xattr_cnt >= MAX_XATTRS_PER_INODE) {
 110                 ubifs_err(c, "inode %lu already has too many xattrs (%d), cannot create more",
 111                           host->i_ino, host_ui->xattr_cnt);
 112                 return -ENOSPC;
 113         }
 114         /*
 115          * Linux limits the maximum size of the extended attribute names list
 116          * to %XATTR_LIST_MAX. This means we should not allow creating more
 117          * extended attributes if the name list becomes larger. This limitation
 118          * is artificial for UBIFS, though.
 119          */
 120         names_len = host_ui->xattr_names + host_ui->xattr_cnt + fname_len(nm) + 1;
 121         if (names_len > XATTR_LIST_MAX) {
 122                 ubifs_err(c, "cannot add one more xattr name to inode %lu, total names length would become %d, max. is %d",
 123                           host->i_ino, names_len, XATTR_LIST_MAX);
 124                 return -ENOSPC;
 125         }
 126
 127         err = ubifs_budget_space(c, &req);
 128         if (err)
 129                 return err;
 130
 131         inode = ubifs_new_inode(c, host, S_IFREG | S_IRWXUGO);
 132         if (IS_ERR(inode)) {
 133                 err = PTR_ERR(inode);
 134                 goto out_budg;
 135         }
 136
 137         /* Re-define all operations to be "nothing" */
 138         inode->i_mapping->a_ops = &empty_aops;
 139         inode->i_op = &empty_iops;
 140         inode->i_fop = &empty_fops;
 141
 142         inode->i_flags |= S_SYNC | S_NOATIME | S_NOCMTIME | S_NOQUOTA;
 143         ui = ubifs_inode(inode);
 144         ui->xattr = 1;
 145         ui->flags |= UBIFS_XATTR_FL;
 146         ui->data = kmemdup(value, size, GFP_NOFS);
 147         if (!ui->data) {
 148                 err = -ENOMEM;
 149                 goto out_free;
 150         }
 151         inode->i_size = ui->ui_size = size;
 152         ui->data_len = size;
 153
 154         mutex_lock(&host_ui->ui_mutex);
 155         host->i_ctime = current_time(host);
 156         host_ui->xattr_cnt += 1;
 157         host_ui->xattr_size += CALC_DENT_SIZE(fname_len(nm));
 158         host_ui->xattr_size += CALC_XATTR_BYTES(size);
 159         host_ui->xattr_names += fname_len(nm);
 160
 161         /*
 162          * We handle UBIFS_XATTR_NAME_ENCRYPTION_CONTEXT here because we
 163          * have to set the UBIFS_CRYPT_FL flag on the host inode.
 164          * To avoid multiple updates of the same inode in the same operation,
 165          * let's do it here.
 166          */
 167         if (strcmp(fname_name(nm), UBIFS_XATTR_NAME_ENCRYPTION_CONTEXT) == 0)
 168                 host_ui->flags |= UBIFS_CRYPT_FL;
 169
 170         err = ubifs_jnl_update(c, host, nm, inode, 0, 1);
 171         if (err)
 172                 goto out_cancel;
 173         mutex_unlock(&host_ui->ui_mutex);
 174
 175         ubifs_release_budget(c, &req);
 176         insert_inode_hash(inode);
 177         iput(inode);
 178         return 0;
 179
 180 out_cancel:
 181         host_ui->xattr_cnt -= 1;
 182         host_ui->xattr_size -= CALC_DENT_SIZE(fname_len(nm));
 183         host_ui->xattr_size -= CALC_XATTR_BYTES(size);
 184         host_ui->xattr_names -= fname_len(nm);
 185         host_ui->flags &= ~UBIFS_CRYPT_FL;
 186         mutex_unlock(&host_ui->ui_mutex);
 187 out_free:
 188         make_bad_inode(inode);
 189         iput(inode);
 190 out_budg:
 191         ubifs_release_budget(c, &req);
 192         return err;
 193 }
 194
 195 /**
 196  * change_xattr - change an extended attribute.
 197  * @c: UBIFS file-system description object
 198  * @host: host inode
 199  * @inode: extended attribute inode
 200  * @value: extended attribute value
 201  * @size: size of extended attribute value
 202  *
 203  * This helper function changes the value of extended attribute @inode with new
 204  * data from @value. Returns zero in case of success and a negative error code
 205  * in case of failure.
 206  */
 207 static int change_xattr(struct ubifs_info *c, struct inode *host,
 208                         struct inode *inode, const void *value, int size)
 209 {
 210         int err;
 211         struct ubifs_inode *host_ui = ubifs_inode(host);
 212         struct ubifs_inode *ui = ubifs_inode(inode);
 213         void *buf = NULL;
 214         int old_size;
 215         struct ubifs_budget_req req = { .dirtied_ino = 2,
 216                 .dirtied_ino_d = ALIGN(size, 8) + ALIGN(host_ui->data_len, 8) };
 217
 218         ubifs_assert(ui->data_len == inode->i_size);
 219         err = ubifs_budget_space(c, &req);
 220         if (err)
 221                 return err;
 222
 223         buf = kmemdup(value, size, GFP_NOFS);
 224         if (!buf) {
 225                 err = -ENOMEM;
 226                 goto out_free;
 227         }
 228         mutex_lock(&ui->ui_mutex);
 229         kfree(ui->data);
 230         ui->data = buf;
 231         inode->i_size = ui->ui_size = size;
 232         old_size = ui->data_len;
 233         ui->data_len = size;
 234         mutex_unlock(&ui->ui_mutex);
 235
 236         mutex_lock(&host_ui->ui_mutex);
 237         host->i_ctime = current_time(host);
 238         host_ui->xattr_size -= CALC_XATTR_BYTES(old_size);
 239         host_ui->xattr_size += CALC_XATTR_BYTES(size);
 240
 241         /*
 242          * It is important to write the host inode after the xattr inode
 243          * because if the host inode gets synchronized (via 'fsync()'), then
 244          * the extended attribute inode gets synchronized, because it goes
 245          * before the host inode in the write-buffer.
 246          */
 247         err = ubifs_jnl_change_xattr(c, inode, host);
 248         if (err)
 249                 goto out_cancel;
 250         mutex_unlock(&host_ui->ui_mutex);
 251
 252         ubifs_release_budget(c, &req);
 253         return 0;
 254
 255 out_cancel:
 256         host_ui->xattr_size -= CALC_XATTR_BYTES(size);
 257         host_ui->xattr_size += CALC_XATTR_BYTES(old_size);
 258         mutex_unlock(&host_ui->ui_mutex);
 259         make_bad_inode(inode);
 260 out_free:
 261         ubifs_release_budget(c, &req);
 262         return err;
 263 }
 264
 265 static struct inode *iget_xattr(struct ubifs_info *c, ino_t inum)
 266 {
 267         struct inode *inode;
 268
 269         inode = ubifs_iget(c->vfs_sb, inum);
 270         if (IS_ERR(inode)) {
 271                 ubifs_err(c, "dead extended attribute entry, error %d",
 272                           (int)PTR_ERR(inode));
 273                 return inode;
 274         }
 275         if (ubifs_inode(inode)->xattr)
 276                 return inode;
 277         ubifs_err(c, "corrupt extended attribute entry");
 278         iput(inode);
 279         return ERR_PTR(-EINVAL);
 280 }
 281
 282 int ubifs_xattr_set(struct inode *host, const char *name, const void *value,
 283                     size_t size, int flags, bool check_lock)
 284 {
 285         struct inode *inode;
 286         struct ubifs_info *c = host->i_sb->s_fs_info;
 287         struct fscrypt_name nm = { .disk_name = FSTR_INIT((char *)name, strlen(name))};
 288         struct ubifs_dent_node *xent;
 289         union ubifs_key key;
 290         int err;
 291
 292         if (check_lock)
 293                 ubifs_assert(inode_is_locked(host));
 294
 295         if (size > UBIFS_MAX_INO_DATA)
 296                 return -ERANGE;
 297
 298         if (fname_len(&nm) > UBIFS_MAX_NLEN)
 299                 return -ENAMETOOLONG;
 300
 301         xent = kmalloc(UBIFS_MAX_XENT_NODE_SZ, GFP_NOFS);
 302         if (!xent)
 303                 return -ENOMEM;
 304
 305         /*
 306          * The extended attribute entries are stored in LNC, so multiple
 307          * look-ups do not involve reading the flash.
 308          */
 309         xent_key_init(c, &key, host->i_ino, &nm);
 310         err = ubifs_tnc_lookup_nm(c, &key, xent, &nm);
 311         if (err) {
 312                 if (err != -ENOENT)
 313                         goto out_free;
 314
 315                 if (flags & XATTR_REPLACE)
 316                         /* We are asked not to create the xattr */
 317                         err = -ENODATA;
 318                 else
 319                         err = create_xattr(c, host, &nm, value, size);
 320                 goto out_free;
 321         }
 322
 323         if (flags & XATTR_CREATE) {
 324                 /* We are asked not to replace the xattr */
 325                 err = -EEXIST;
 326                 goto out_free;
 327         }
 328
 329         inode = iget_xattr(c, le64_to_cpu(xent->inum));
 330         if (IS_ERR(inode)) {
 331                 err = PTR_ERR(inode);
 332                 goto out_free;
 333         }
 334
 335         err = change_xattr(c, host, inode, value, size);
 336         iput(inode);
 337
 338 out_free:
 339         kfree(xent);
 340         return err;
 341 }
 342
 343 ssize_t ubifs_xattr_get(struct inode *host, const char *name, void *buf,
 344                         size_t size)
 345 {
 346         struct inode *inode;
 347         struct ubifs_info *c = host->i_sb->s_fs_info;
 348         struct fscrypt_name nm = { .disk_name = FSTR_INIT((char *)name, strlen(name))};
 349         struct ubifs_inode *ui;
 350         struct ubifs_dent_node *xent;
 351         union ubifs_key key;
 352         int err;
 353
 354         if (fname_len(&nm) > UBIFS_MAX_NLEN)
 355                 return -ENAMETOOLONG;
 356
 357         xent = kmalloc(UBIFS_MAX_XENT_NODE_SZ, GFP_NOFS);
 358         if (!xent)
 359                 return -ENOMEM;
 360
 361         xent_key_init(c, &key, host->i_ino, &nm);
 362         err = ubifs_tnc_lookup_nm(c, &key, xent, &nm);
 363         if (err) {
 364                 if (err == -ENOENT)
 365                         err = -ENODATA;
 366                 goto out_unlock;
 367         }
 368
 369         inode = iget_xattr(c, le64_to_cpu(xent->inum));
 370         if (IS_ERR(inode)) {
 371                 err = PTR_ERR(inode);
 372                 goto out_unlock;
 373         }
 374
 375         ui = ubifs_inode(inode);
 376         ubifs_assert(inode->i_size == ui->data_len);
 377         ubifs_assert(ubifs_inode(host)->xattr_size > ui->data_len);
 378
 379         mutex_lock(&ui->ui_mutex);
 380         if (buf) {
 381                 /* If @buf is %NULL we are supposed to return the length */
 382                 if (ui->data_len > size) {
 383                         ubifs_err(c, "buffer size %zd, xattr len %d",
 384                                   size, ui->data_len);
 385                         err = -ERANGE;
 386                         goto out_iput;
 387                 }
 388
 389                 memcpy(buf, ui->data, ui->data_len);
 390         }
 391         err = ui->data_len;
 392
 393 out_iput:
 394         mutex_unlock(&ui->ui_mutex);
 395         iput(inode);
 396 out_unlock:
 397         kfree(xent);
 398         return err;
 399 }
 400
 401 static bool xattr_visible(const char *name)
 402 {
 403         /* File encryption related xattrs are for internal use only */
 404         if (strcmp(name, UBIFS_XATTR_NAME_ENCRYPTION_CONTEXT) == 0)
 405                 return false;
 406
 407         /* Show trusted namespace only for "power" users */
 408         if (strncmp(name, XATTR_TRUSTED_PREFIX,
 409                     XATTR_TRUSTED_PREFIX_LEN) == 0 && !capable(CAP_SYS_ADMIN))
 410                 return false;
 411
 412         return true;
 413 }
 414
 415 ssize_t ubifs_listxattr(struct dentry *dentry, char *buffer, size_t size)
 416 {
 417         union ubifs_key key;
 418         struct inode *host = d_inode(dentry);
 419         struct ubifs_info *c = host->i_sb->s_fs_info;
 420         struct ubifs_inode *host_ui = ubifs_inode(host);
 421         struct ubifs_dent_node *xent, *pxent = NULL;
 422         int err, len, written = 0;
 423         struct fscrypt_name nm = {0};
 424
 425         dbg_gen("ino %lu ('%pd'), buffer size %zd", host->i_ino,
 426                 dentry, size);
 427
 428         len = host_ui->xattr_names + host_ui->xattr_cnt;
 429         if (!buffer)
 430                 /*
 431                  * We should return the minimum buffer size which will fit a
 432                  * null-terminated list of all the extended attribute names.
 433                  */
 434                 return len;
 435
 436         if (len > size)
 437                 return -ERANGE;
 438
 439         lowest_xent_key(c, &key, host->i_ino);
 440         while (1) {
 441                 xent = ubifs_tnc_next_ent(c, &key, &nm);
 442                 if (IS_ERR(xent)) {
 443                         err = PTR_ERR(xent);
 444                         break;
 445                 }
 446
 447                 fname_name(&nm) = xent->name;
 448                 fname_len(&nm) = le16_to_cpu(xent->nlen);
 449
 450                 if (xattr_visible(xent->name)) {
 451                         memcpy(buffer + written, fname_name(&nm), fname_len(&nm) + 1);
 452                         written += fname_len(&nm) + 1;
 453                 }
 454
 455                 kfree(pxent);
 456                 pxent = xent;
 457                 key_read(c, &xent->key, &key);
 458         }
 459
 460         kfree(pxent);
 461         if (err != -ENOENT) {
 462                 ubifs_err(c, "cannot find next direntry, error %d", err);
 463                 return err;
 464         }
 465
 466         ubifs_assert(written <= size);
 467         return written;
 468 }
 469
 470 static int remove_xattr(struct ubifs_info *c, struct inode *host,
 471                         struct inode *inode, const struct fscrypt_name *nm)
 472 {
 473         int err;
 474         struct ubifs_inode *host_ui = ubifs_inode(host);
 475         struct ubifs_inode *ui = ubifs_inode(inode);
 476         struct ubifs_budget_req req = { .dirtied_ino = 2, .mod_dent = 1,
 477                                 .dirtied_ino_d = ALIGN(host_ui->data_len, 8) };
 478
 479         ubifs_assert(ui->data_len == inode->i_size);
 480
 481         err = ubifs_budget_space(c, &req);
 482         if (err)
 483                 return err;
 484
 485         mutex_lock(&host_ui->ui_mutex);
 486         host->i_ctime = current_time(host);
 487         host_ui->xattr_cnt -= 1;
 488         host_ui->xattr_size -= CALC_DENT_SIZE(fname_len(nm));
 489         host_ui->xattr_size -= CALC_XATTR_BYTES(ui->data_len);
 490         host_ui->xattr_names -= fname_len(nm);
 491
 492         err = ubifs_jnl_delete_xattr(c, host, inode, nm);
 493         if (err)
 494                 goto out_cancel;
 495         mutex_unlock(&host_ui->ui_mutex);
 496
 497         ubifs_release_budget(c, &req);
 498         return 0;
 499
 500 out_cancel:
 501         host_ui->xattr_cnt += 1;
 502         host_ui->xattr_size += CALC_DENT_SIZE(fname_len(nm));
 503         host_ui->xattr_size += CALC_XATTR_BYTES(ui->data_len);
 504         host_ui->xattr_names += fname_len(nm);
 505         mutex_unlock(&host_ui->ui_mutex);
 506         ubifs_release_budget(c, &req);
 507         make_bad_inode(inode);
 508         return err;
 509 }
 510
 511 /**
 512  * ubifs_evict_xattr_inode - Evict an xattr inode.
 513  * @c: UBIFS file-system description object
 514  * @xattr_inum: xattr inode number
 515  *
 516  * When an inode that hosts xattrs is being removed we have to make sure
 517  * that cached inodes of the xattrs also get removed from the inode cache
 518  * otherwise we'd waste memory. This function looks up an inode from the
 519  * inode cache and clears the link counter such that iput() will evict
 520  * the inode.
 521  */
 522 void ubifs_evict_xattr_inode(struct ubifs_info *c, ino_t xattr_inum)
 523 {
 524         struct inode *inode;
 525
 526         inode = ilookup(c->vfs_sb, xattr_inum);
 527         if (inode) {
 528                 clear_nlink(inode);
 529                 iput(inode);
 530         }
 531 }
 532
 533 static int ubifs_xattr_remove(struct inode *host, const char *name)
 534 {
 535         struct inode *inode;
 536         struct ubifs_info *c = host->i_sb->s_fs_info;
 537         struct fscrypt_name nm = { .disk_name = FSTR_INIT((char *)name, strlen(name))};
 538         struct ubifs_dent_node *xent;
 539         union ubifs_key key;
 540         int err;
 541
 542         ubifs_assert(inode_is_locked(host));
 543
 544         if (fname_len(&nm) > UBIFS_MAX_NLEN)
 545                 return -ENAMETOOLONG;
 546
 547         xent = kmalloc(UBIFS_MAX_XENT_NODE_SZ, GFP_NOFS);
 548         if (!xent)
 549                 return -ENOMEM;
 550
 551         xent_key_init(c, &key, host->i_ino, &nm);
 552         err = ubifs_tnc_lookup_nm(c, &key, xent, &nm);
 553         if (err) {
 554                 if (err == -ENOENT)
 555                         err = -ENODATA;
 556                 goto out_free;
 557         }
 558
 559         inode = iget_xattr(c, le64_to_cpu(xent->inum));
 560         if (IS_ERR(inode)) {
 561                 err = PTR_ERR(inode);
 562                 goto out_free;
 563         }
 564
 565         ubifs_assert(inode->i_nlink == 1);
 566         clear_nlink(inode);
 567         err = remove_xattr(c, host, inode, &nm);
 568         if (err)
 569                 set_nlink(inode, 1);
 570
 571         /* If @i_nlink is 0, 'iput()' will delete the inode */
 572         iput(inode);
 573
 574 out_free:
 575         kfree(xent);
 576         return err;
 577 }
 578
 579 #ifdef CONFIG_UBIFS_FS_SECURITY
 580 static int init_xattrs(struct inode *inode, const struct xattr *xattr_array,
 581                       void *fs_info)
 582 {
 583         const struct xattr *xattr;
 584         char *name;
 585         int err = 0;
 586
 587         for (xattr = xattr_array; xattr->name != NULL; xattr++) {
 588                 name = kmalloc(XATTR_SECURITY_PREFIX_LEN +
 589                                strlen(xattr->name) + 1, GFP_NOFS);
 590                 if (!name) {
 591                         err = -ENOMEM;
 592                         break;
 593                 }
 594                 strcpy(name, XATTR_SECURITY_PREFIX);
 595                 strcpy(name + XATTR_SECURITY_PREFIX_LEN, xattr->name);
 596                 /*
 597                  * creating a new inode without holding the inode rwsem,
 598                  * no need to check whether inode is locked.
 599                  */
 600                 err = ubifs_xattr_set(inode, name, xattr->value,
 601                                       xattr->value_len, 0, false);
 602                 kfree(name);
 603                 if (err < 0)
 604                         break;
 605         }
 606
 607         return err;
 608 }
 609
 610 int ubifs_init_security(struct inode *dentry, struct inode *inode,
 611                         const struct qstr *qstr)
 612 {
 613         int err;
 614
 615         err = security_inode_init_security(inode, dentry, qstr,
 616                                            &init_xattrs, 0);
 617         if (err) {
 618                 struct ubifs_info *c = dentry->i_sb->s_fs_info;
 619                 ubifs_err(c, "cannot initialize security for inode %lu, error %d",
 620                           inode->i_ino, err);
 621         }
 622         return err;
 623 }
 624 #endif
 625
 626 static int xattr_get(const struct xattr_handler *handler,
 627                            struct dentry *dentry, struct inode *inode,
 628                            const char *name, void *buffer, size_t size)
 629 {
 630         dbg_gen("xattr '%s', ino %lu ('%pd'), buf size %zd", name,
 631                 inode->i_ino, dentry, size);
 632
 633         name = xattr_full_name(handler, name);
 634         return ubifs_xattr_get(inode, name, buffer, size);
 635 }
 636
 637 static int xattr_set(const struct xattr_handler *handler,
 638                            struct dentry *dentry, struct inode *inode,
 639                            const char *name, const void *value,
 640                            size_t size, int flags)
 641 {
 642         dbg_gen("xattr '%s', host ino %lu ('%pd'), size %zd",
 643                 name, inode->i_ino, dentry, size);
 644
 645         name = xattr_full_name(handler, name);
 646
 647         if (value)
 648                 return ubifs_xattr_set(inode, name, value, size, flags, true);
 649         else
 650                 return ubifs_xattr_remove(inode, name);
 651 }
 652
 653 static const struct xattr_handler ubifs_user_xattr_handler = {
 654         .prefix = XATTR_USER_PREFIX,
 655         .get = xattr_get,
 656         .set = xattr_set,
 657 };
 658
 659 static const struct xattr_handler ubifs_trusted_xattr_handler = {
 660         .prefix = XATTR_TRUSTED_PREFIX,
 661         .get = xattr_get,
 662         .set = xattr_set,
 663 };
 664
 665 #ifdef CONFIG_UBIFS_FS_SECURITY
 666 static const struct xattr_handler ubifs_security_xattr_handler = {
 667         .prefix = XATTR_SECURITY_PREFIX,
 668         .get = xattr_get,
 669         .set = xattr_set,
 670 };
 671 #endif
 672
 673 const struct xattr_handler *ubifs_xattr_handlers[] = {
 674         &ubifs_user_xattr_handler,
 675         &ubifs_trusted_xattr_handler,
 676 #ifdef CONFIG_UBIFS_FS_SECURITY
 677         &ubifs_security_xattr_handler,
 678 #endif
 679         NULL
 680 };