fs/xfs/xfs_attr_list.c

   1 /*
   2  * Copyright (c) 2000-2005 Silicon Graphics, Inc.
   3  * Copyright (c) 2013 Red Hat, Inc.
   4  * All Rights Reserved.
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License as
   8  * published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it would be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write the Free Software Foundation,
  17  * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  18  */
  19 #include "xfs.h"
  20 #include "xfs_fs.h"
  21 #include "xfs_log_format.h"
  22 #include "xfs_trans_resv.h"
  23 #include "xfs_bit.h"
  24 #include "xfs_sb.h"
  25 #include "xfs_ag.h"
  26 #include "xfs_mount.h"
  27 #include "xfs_da_format.h"
  28 #include "xfs_da_btree.h"
  29 #include "xfs_bmap_btree.h"
  30 #include "xfs_alloc_btree.h"
  31 #include "xfs_ialloc_btree.h"
  32 #include "xfs_alloc.h"
  33 #include "xfs_btree.h"
  34 #include "xfs_attr_sf.h"
  35 #include "xfs_attr_remote.h"
  36 #include "xfs_dinode.h"
  37 #include "xfs_inode.h"
  38 #include "xfs_trans.h"
  39 #include "xfs_inode_item.h"
  40 #include "xfs_bmap.h"
  41 #include "xfs_attr.h"
  42 #include "xfs_attr_leaf.h"
  43 #include "xfs_error.h"
  44 #include "xfs_trace.h"
  45 #include "xfs_buf_item.h"
  46 #include "xfs_cksum.h"
  47
  48 STATIC int
  49 xfs_attr_shortform_compare(const void *a, const void *b)
  50 {
  51         xfs_attr_sf_sort_t *sa, *sb;
  52
  53         sa = (xfs_attr_sf_sort_t *)a;
  54         sb = (xfs_attr_sf_sort_t *)b;
  55         if (sa->hash < sb->hash) {
  56                 return(-1);
  57         } else if (sa->hash > sb->hash) {
  58                 return(1);
  59         } else {
  60                 return(sa->entno - sb->entno);
  61         }
  62 }
  63
  64 #define XFS_ISRESET_CURSOR(cursor) \
  65         (!((cursor)->initted) && !((cursor)->hashval) && \
  66          !((cursor)->blkno) && !((cursor)->offset))
  67 /*
  68  * Copy out entries of shortform attribute lists for attr_list().
  69  * Shortform attribute lists are not stored in hashval sorted order.
  70  * If the output buffer is not large enough to hold them all, then we
  71  * we have to calculate each entries' hashvalue and sort them before
  72  * we can begin returning them to the user.
  73  */
  74 int
  75 xfs_attr_shortform_list(xfs_attr_list_context_t *context)
  76 {
  77         attrlist_cursor_kern_t *cursor;
  78         xfs_attr_sf_sort_t *sbuf, *sbp;
  79         xfs_attr_shortform_t *sf;
  80         xfs_attr_sf_entry_t *sfe;
  81         xfs_inode_t *dp;
  82         int sbsize, nsbuf, count, i;
  83         int error;
  84
  85         ASSERT(context != NULL);
  86         dp = context->dp;
  87         ASSERT(dp != NULL);
  88         ASSERT(dp->i_afp != NULL);
  89         sf = (xfs_attr_shortform_t *)dp->i_afp->if_u1.if_data;
  90         ASSERT(sf != NULL);
  91         if (!sf->hdr.count)
  92                 return(0);
  93         cursor = context->cursor;
  94         ASSERT(cursor != NULL);
  95
  96         trace_xfs_attr_list_sf(context);
  97
  98         /*
  99          * If the buffer is large enough and the cursor is at the start,
 100          * do not bother with sorting since we will return everything in
 101          * one buffer and another call using the cursor won't need to be
 102          * made.
 103          * Note the generous fudge factor of 16 overhead bytes per entry.
 104          * If bufsize is zero then put_listent must be a search function
 105          * and can just scan through what we have.
 106          */
 107         if (context->bufsize == 0 ||
 108             (XFS_ISRESET_CURSOR(cursor) &&
 109              (dp->i_afp->if_bytes + sf->hdr.count * 16) < context->bufsize)) {
 110                 for (i = 0, sfe = &sf->list[0]; i < sf->hdr.count; i++) {
 111                         error = context->put_listent(context,
 112                                            sfe->flags,
 113                                            sfe->nameval,
 114                                            (int)sfe->namelen,
 115                                            (int)sfe->valuelen,
 116                                            &sfe->nameval[sfe->namelen]);
 117
 118                         /*
 119                          * Either search callback finished early or
 120                          * didn't fit it all in the buffer after all.
 121                          */
 122                         if (context->seen_enough)
 123                                 break;
 124
 125                         if (error)
 126                                 return error;
 127                         sfe = XFS_ATTR_SF_NEXTENTRY(sfe);
 128                 }
 129                 trace_xfs_attr_list_sf_all(context);
 130                 return(0);
 131         }
 132
 133         /* do no more for a search callback */
 134         if (context->bufsize == 0)
 135                 return 0;
 136
 137         /*
 138          * It didn't all fit, so we have to sort everything on hashval.
 139          */
 140         sbsize = sf->hdr.count * sizeof(*sbuf);
 141         sbp = sbuf = kmem_alloc(sbsize, KM_SLEEP | KM_NOFS);
 142
 143         /*
 144          * Scan the attribute list for the rest of the entries, storing
 145          * the relevant info from only those that match into a buffer.
 146          */
 147         nsbuf = 0;
 148         for (i = 0, sfe = &sf->list[0]; i < sf->hdr.count; i++) {
 149                 if (unlikely(
 150                     ((char *)sfe < (char *)sf) ||
 151                     ((char *)sfe >= ((char *)sf + dp->i_afp->if_bytes)))) {
 152                         XFS_CORRUPTION_ERROR("xfs_attr_shortform_list",
 153                                              XFS_ERRLEVEL_LOW,
 154                                              context->dp->i_mount, sfe);
 155                         kmem_free(sbuf);
 156                         return XFS_ERROR(EFSCORRUPTED);
 157                 }
 158
 159                 sbp->entno = i;
 160                 sbp->hash = xfs_da_hashname(sfe->nameval, sfe->namelen);
 161                 sbp->name = sfe->nameval;
 162                 sbp->namelen = sfe->namelen;
 163                 /* These are bytes, and both on-disk, don't endian-flip */
 164                 sbp->valuelen = sfe->valuelen;
 165                 sbp->flags = sfe->flags;
 166                 sfe = XFS_ATTR_SF_NEXTENTRY(sfe);
 167                 sbp++;
 168                 nsbuf++;
 169         }
 170
 171         /*
 172          * Sort the entries on hash then entno.
 173          */
 174         xfs_sort(sbuf, nsbuf, sizeof(*sbuf), xfs_attr_shortform_compare);
 175
 176         /*
 177          * Re-find our place IN THE SORTED LIST.
 178          */
 179         count = 0;
 180         cursor->initted = 1;
 181         cursor->blkno = 0;
 182         for (sbp = sbuf, i = 0; i < nsbuf; i++, sbp++) {
 183                 if (sbp->hash == cursor->hashval) {
 184                         if (cursor->offset == count) {
 185                                 break;
 186                         }
 187                         count++;
 188                 } else if (sbp->hash > cursor->hashval) {
 189                         break;
 190                 }
 191         }
 192         if (i == nsbuf) {
 193                 kmem_free(sbuf);
 194                 return(0);
 195         }
 196
 197         /*
 198          * Loop putting entries into the user buffer.
 199          */
 200         for ( ; i < nsbuf; i++, sbp++) {
 201                 if (cursor->hashval != sbp->hash) {
 202                         cursor->hashval = sbp->hash;
 203                         cursor->offset = 0;
 204                 }
 205                 error = context->put_listent(context,
 206                                         sbp->flags,
 207                                         sbp->name,
 208                                         sbp->namelen,
 209                                         sbp->valuelen,
 210                                         &sbp->name[sbp->namelen]);
 211                 if (error)
 212                         return error;
 213                 if (context->seen_enough)
 214                         break;
 215                 cursor->offset++;
 216         }
 217
 218         kmem_free(sbuf);
 219         return(0);
 220 }
 221
 222 STATIC int
 223 xfs_attr_node_list(xfs_attr_list_context_t *context)
 224 {
 225         attrlist_cursor_kern_t *cursor;
 226         xfs_attr_leafblock_t *leaf;
 227         xfs_da_intnode_t *node;
 228         struct xfs_attr3_icleaf_hdr leafhdr;
 229         struct xfs_da3_icnode_hdr nodehdr;
 230         struct xfs_da_node_entry *btree;
 231         int error, i;
 232         struct xfs_buf *bp;
 233
 234         trace_xfs_attr_node_list(context);
 235
 236         cursor = context->cursor;
 237         cursor->initted = 1;
 238
 239         /*
 240          * Do all sorts of validation on the passed-in cursor structure.
 241          * If anything is amiss, ignore the cursor and look up the hashval
 242          * starting from the btree root.
 243          */
 244         bp = NULL;
 245         if (cursor->blkno > 0) {
 246                 error = xfs_da3_node_read(NULL, context->dp, cursor->blkno, -1,
 247                                               &bp, XFS_ATTR_FORK);
 248                 if ((error != 0) && (error != EFSCORRUPTED))
 249                         return(error);
 250                 if (bp) {
 251                         struct xfs_attr_leaf_entry *entries;
 252
 253                         node = bp->b_addr;
 254                         switch (be16_to_cpu(node->hdr.info.magic)) {
 255                         case XFS_DA_NODE_MAGIC:
 256                         case XFS_DA3_NODE_MAGIC:
 257                                 trace_xfs_attr_list_wrong_blk(context);
 258                                 xfs_trans_brelse(NULL, bp);
 259                                 bp = NULL;
 260                                 break;
 261                         case XFS_ATTR_LEAF_MAGIC:
 262                         case XFS_ATTR3_LEAF_MAGIC:
 263                                 leaf = bp->b_addr;
 264                                 xfs_attr3_leaf_hdr_from_disk(&leafhdr, leaf);
 265                                 entries = xfs_attr3_leaf_entryp(leaf);
 266                                 if (cursor->hashval > be32_to_cpu(
 267                                                 entries[leafhdr.count - 1].hashval)) {
 268                                         trace_xfs_attr_list_wrong_blk(context);
 269                                         xfs_trans_brelse(NULL, bp);
 270                                         bp = NULL;
 271                                 } else if (cursor->hashval <= be32_to_cpu(
 272                                                 entries[0].hashval)) {
 273                                         trace_xfs_attr_list_wrong_blk(context);
 274                                         xfs_trans_brelse(NULL, bp);
 275                                         bp = NULL;
 276                                 }
 277                                 break;
 278                         default:
 279                                 trace_xfs_attr_list_wrong_blk(context);
 280                                 xfs_trans_brelse(NULL, bp);
 281                                 bp = NULL;
 282                         }
 283                 }
 284         }
 285
 286         /*
 287          * We did not find what we expected given the cursor's contents,
 288          * so we start from the top and work down based on the hash value.
 289          * Note that start of node block is same as start of leaf block.
 290          */
 291         if (bp == NULL) {
 292                 cursor->blkno = 0;
 293                 for (;;) {
 294                         __uint16_t magic;
 295
 296                         error = xfs_da3_node_read(NULL, context->dp,
 297                                                       cursor->blkno, -1, &bp,
 298                                                       XFS_ATTR_FORK);
 299                         if (error)
 300                                 return(error);
 301                         node = bp->b_addr;
 302                         magic = be16_to_cpu(node->hdr.info.magic);
 303                         if (magic == XFS_ATTR_LEAF_MAGIC ||
 304                             magic == XFS_ATTR3_LEAF_MAGIC)
 305                                 break;
 306                         if (magic != XFS_DA_NODE_MAGIC &&
 307                             magic != XFS_DA3_NODE_MAGIC) {
 308                                 XFS_CORRUPTION_ERROR("xfs_attr_node_list(3)",
 309                                                      XFS_ERRLEVEL_LOW,
 310                                                      context->dp->i_mount,
 311                                                      node);
 312                                 xfs_trans_brelse(NULL, bp);
 313                                 return XFS_ERROR(EFSCORRUPTED);
 314                         }
 315
 316                         xfs_da3_node_hdr_from_disk(&nodehdr, node);
 317                         btree = xfs_da3_node_tree_p(node);
 318                         for (i = 0; i < nodehdr.count; btree++, i++) {
 319                                 if (cursor->hashval
 320                                                 <= be32_to_cpu(btree->hashval)) {
 321                                         cursor->blkno = be32_to_cpu(btree->before);
 322                                         trace_xfs_attr_list_node_descend(context,
 323                                                                          btree);
 324                                         break;
 325                                 }
 326                         }
 327                         if (i == nodehdr.count) {
 328                                 xfs_trans_brelse(NULL, bp);
 329                                 return 0;
 330                         }
 331                         xfs_trans_brelse(NULL, bp);
 332                 }
 333         }
 334         ASSERT(bp != NULL);
 335
 336         /*
 337          * Roll upward through the blocks, processing each leaf block in
 338          * order.  As long as there is space in the result buffer, keep
 339          * adding the information.
 340          */
 341         for (;;) {
 342                 leaf = bp->b_addr;
 343                 error = xfs_attr3_leaf_list_int(bp, context);
 344                 if (error) {
 345                         xfs_trans_brelse(NULL, bp);
 346                         return error;
 347                 }
 348                 xfs_attr3_leaf_hdr_from_disk(&leafhdr, leaf);
 349                 if (context->seen_enough || leafhdr.forw == 0)
 350                         break;
 351                 cursor->blkno = leafhdr.forw;
 352                 xfs_trans_brelse(NULL, bp);
 353                 error = xfs_attr3_leaf_read(NULL, context->dp, cursor->blkno, -1,
 354                                            &bp);
 355                 if (error)
 356                         return error;
 357         }
 358         xfs_trans_brelse(NULL, bp);
 359         return 0;
 360 }
 361
 362 /*
 363  * Copy out attribute list entries for attr_list(), for leaf attribute lists.
 364  */
 365 int
 366 xfs_attr3_leaf_list_int(
 367         struct xfs_buf                  *bp,
 368         struct xfs_attr_list_context    *context)
 369 {
 370         struct attrlist_cursor_kern     *cursor;
 371         struct xfs_attr_leafblock       *leaf;
 372         struct xfs_attr3_icleaf_hdr     ichdr;
 373         struct xfs_attr_leaf_entry      *entries;
 374         struct xfs_attr_leaf_entry      *entry;
 375         int                             retval;
 376         int                             i;
 377
 378         trace_xfs_attr_list_leaf(context);
 379
 380         leaf = bp->b_addr;
 381         xfs_attr3_leaf_hdr_from_disk(&ichdr, leaf);
 382         entries = xfs_attr3_leaf_entryp(leaf);
 383
 384         cursor = context->cursor;
 385         cursor->initted = 1;
 386
 387         /*
 388          * Re-find our place in the leaf block if this is a new syscall.
 389          */
 390         if (context->resynch) {
 391                 entry = &entries[0];
 392                 for (i = 0; i < ichdr.count; entry++, i++) {
 393                         if (be32_to_cpu(entry->hashval) == cursor->hashval) {
 394                                 if (cursor->offset == context->dupcnt) {
 395                                         context->dupcnt = 0;
 396                                         break;
 397                                 }
 398                                 context->dupcnt++;
 399                         } else if (be32_to_cpu(entry->hashval) >
 400                                         cursor->hashval) {
 401                                 context->dupcnt = 0;
 402                                 break;
 403                         }
 404                 }
 405                 if (i == ichdr.count) {
 406                         trace_xfs_attr_list_notfound(context);
 407                         return 0;
 408                 }
 409         } else {
 410                 entry = &entries[0];
 411                 i = 0;
 412         }
 413         context->resynch = 0;
 414
 415         /*
 416          * We have found our place, start copying out the new attributes.
 417          */
 418         retval = 0;
 419         for (; i < ichdr.count; entry++, i++) {
 420                 if (be32_to_cpu(entry->hashval) != cursor->hashval) {
 421                         cursor->hashval = be32_to_cpu(entry->hashval);
 422                         cursor->offset = 0;
 423                 }
 424
 425                 if (entry->flags & XFS_ATTR_INCOMPLETE)
 426                         continue;               /* skip incomplete entries */
 427
 428                 if (entry->flags & XFS_ATTR_LOCAL) {
 429                         xfs_attr_leaf_name_local_t *name_loc =
 430                                 xfs_attr3_leaf_name_local(leaf, i);
 431
 432                         retval = context->put_listent(context,
 433                                                 entry->flags,
 434                                                 name_loc->nameval,
 435                                                 (int)name_loc->namelen,
 436                                                 be16_to_cpu(name_loc->valuelen),
 437                                                 &name_loc->nameval[name_loc->namelen]);
 438                         if (retval)
 439                                 return retval;
 440                 } else {
 441                         xfs_attr_leaf_name_remote_t *name_rmt =
 442                                 xfs_attr3_leaf_name_remote(leaf, i);
 443
 444                         int valuelen = be32_to_cpu(name_rmt->valuelen);
 445
 446                         if (context->put_value) {
 447                                 xfs_da_args_t args;
 448
 449                                 memset((char *)&args, 0, sizeof(args));
 450                                 args.dp = context->dp;
 451                                 args.whichfork = XFS_ATTR_FORK;
 452                                 args.valuelen = valuelen;
 453                                 args.value = kmem_alloc(valuelen, KM_SLEEP | KM_NOFS);
 454                                 args.rmtblkno = be32_to_cpu(name_rmt->valueblk);
 455                                 args.rmtblkcnt = xfs_attr3_rmt_blocks(
 456                                                         args.dp->i_mount, valuelen);
 457                                 retval = xfs_attr_rmtval_get(&args);
 458                                 if (retval)
 459                                         return retval;
 460                                 retval = context->put_listent(context,
 461                                                 entry->flags,
 462                                                 name_rmt->name,
 463                                                 (int)name_rmt->namelen,
 464                                                 valuelen,
 465                                                 args.value);
 466                                 kmem_free(args.value);
 467                         } else {
 468                                 retval = context->put_listent(context,
 469                                                 entry->flags,
 470                                                 name_rmt->name,
 471                                                 (int)name_rmt->namelen,
 472                                                 valuelen,
 473                                                 NULL);
 474                         }
 475                         if (retval)
 476                                 return retval;
 477                 }
 478                 if (context->seen_enough)
 479                         break;
 480                 cursor->offset++;
 481         }
 482         trace_xfs_attr_list_leaf_end(context);
 483         return retval;
 484 }
 485
 486 /*
 487  * Copy out attribute entries for attr_list(), for leaf attribute lists.
 488  */
 489 STATIC int
 490 xfs_attr_leaf_list(xfs_attr_list_context_t *context)
 491 {
 492         int error;
 493         struct xfs_buf *bp;
 494
 495         trace_xfs_attr_leaf_list(context);
 496
 497         context->cursor->blkno = 0;
 498         error = xfs_attr3_leaf_read(NULL, context->dp, 0, -1, &bp);
 499         if (error)
 500                 return XFS_ERROR(error);
 501
 502         error = xfs_attr3_leaf_list_int(bp, context);
 503         xfs_trans_brelse(NULL, bp);
 504         return XFS_ERROR(error);
 505 }
 506
 507 int
 508 xfs_attr_list_int(
 509         xfs_attr_list_context_t *context)
 510 {
 511         int error;
 512         xfs_inode_t *dp = context->dp;
 513
 514         XFS_STATS_INC(xs_attr_list);
 515
 516         if (XFS_FORCED_SHUTDOWN(dp->i_mount))
 517                 return EIO;
 518
 519         xfs_ilock(dp, XFS_ILOCK_SHARED);
 520
 521         /*
 522          * Decide on what work routines to call based on the inode size.
 523          */
 524         if (!xfs_inode_hasattr(dp)) {
 525                 error = 0;
 526         } else if (dp->i_d.di_aformat == XFS_DINODE_FMT_LOCAL) {
 527                 error = xfs_attr_shortform_list(context);
 528         } else if (xfs_bmap_one_block(dp, XFS_ATTR_FORK)) {
 529                 error = xfs_attr_leaf_list(context);
 530         } else {
 531                 error = xfs_attr_node_list(context);
 532         }
 533
 534         xfs_iunlock(dp, XFS_ILOCK_SHARED);
 535
 536         return error;
 537 }
 538
 539 #define ATTR_ENTBASESIZE                /* minimum bytes used by an attr */ \
 540         (((struct attrlist_ent *) 0)->a_name - (char *) 0)
 541 #define ATTR_ENTSIZE(namelen)           /* actual bytes used by an attr */ \
 542         ((ATTR_ENTBASESIZE + (namelen) + 1 + sizeof(u_int32_t)-1) \
 543          & ~(sizeof(u_int32_t)-1))
 544
 545 /*
 546  * Format an attribute and copy it out to the user's buffer.
 547  * Take care to check values and protect against them changing later,
 548  * we may be reading them directly out of a user buffer.
 549  */
 550 STATIC int
 551 xfs_attr_put_listent(
 552         xfs_attr_list_context_t *context,
 553         int             flags,
 554         unsigned char   *name,
 555         int             namelen,
 556         int             valuelen,
 557         unsigned char   *value)
 558 {
 559         struct attrlist *alist = (struct attrlist *)context->alist;
 560         attrlist_ent_t *aep;
 561         int arraytop;
 562
 563         ASSERT(!(context->flags & ATTR_KERNOVAL));
 564         ASSERT(context->count >= 0);
 565         ASSERT(context->count < (ATTR_MAX_VALUELEN/8));
 566         ASSERT(context->firstu >= sizeof(*alist));
 567         ASSERT(context->firstu <= context->bufsize);
 568
 569         /*
 570          * Only list entries in the right namespace.
 571          */
 572         if (((context->flags & ATTR_SECURE) == 0) !=
 573             ((flags & XFS_ATTR_SECURE) == 0))
 574                 return 0;
 575         if (((context->flags & ATTR_ROOT) == 0) !=
 576             ((flags & XFS_ATTR_ROOT) == 0))
 577                 return 0;
 578
 579         arraytop = sizeof(*alist) +
 580                         context->count * sizeof(alist->al_offset[0]);
 581         context->firstu -= ATTR_ENTSIZE(namelen);
 582         if (context->firstu < arraytop) {
 583                 trace_xfs_attr_list_full(context);
 584                 alist->al_more = 1;
 585                 context->seen_enough = 1;
 586                 return 1;
 587         }
 588
 589         aep = (attrlist_ent_t *)&context->alist[context->firstu];
 590         aep->a_valuelen = valuelen;
 591         memcpy(aep->a_name, name, namelen);
 592         aep->a_name[namelen] = 0;
 593         alist->al_offset[context->count++] = context->firstu;
 594         alist->al_count = context->count;
 595         trace_xfs_attr_list_add(context);
 596         return 0;
 597 }
 598
 599 /*
 600  * Generate a list of extended attribute names and optionally
 601  * also value lengths.  Positive return value follows the XFS
 602  * convention of being an error, zero or negative return code
 603  * is the length of the buffer returned (negated), indicating
 604  * success.
 605  */
 606 int
 607 xfs_attr_list(
 608         xfs_inode_t     *dp,
 609         char            *buffer,
 610         int             bufsize,
 611         int             flags,
 612         attrlist_cursor_kern_t *cursor)
 613 {
 614         xfs_attr_list_context_t context;
 615         struct attrlist *alist;
 616         int error;
 617
 618         /*
 619          * Validate the cursor.
 620          */
 621         if (cursor->pad1 || cursor->pad2)
 622                 return(XFS_ERROR(EINVAL));
 623         if ((cursor->initted == 0) &&
 624             (cursor->hashval || cursor->blkno || cursor->offset))
 625                 return XFS_ERROR(EINVAL);
 626
 627         /*
 628          * Check for a properly aligned buffer.
 629          */
 630         if (((long)buffer) & (sizeof(int)-1))
 631                 return XFS_ERROR(EFAULT);
 632         if (flags & ATTR_KERNOVAL)
 633                 bufsize = 0;
 634
 635         /*
 636          * Initialize the output buffer.
 637          */
 638         memset(&context, 0, sizeof(context));
 639         context.dp = dp;
 640         context.cursor = cursor;
 641         context.resynch = 1;
 642         context.flags = flags;
 643         context.alist = buffer;
 644         context.bufsize = (bufsize & ~(sizeof(int)-1));  /* align */
 645         context.firstu = context.bufsize;
 646         context.put_listent = xfs_attr_put_listent;
 647
 648         alist = (struct attrlist *)context.alist;
 649         alist->al_count = 0;
 650         alist->al_more = 0;
 651         alist->al_offset[0] = context.bufsize;
 652
 653         error = xfs_attr_list_int(&context);
 654         ASSERT(error >= 0);
 655         return error;
 656 }