root/fs/xfs/xfs_attr_list.c

DEFINITIONS

1. xfs_attr_shortform_compare
2. xfs_attr_shortform_list
3. xfs_attr_node_list_lookup
4. xfs_attr_node_list
5. xfs_attr3_leaf_list_int
6. xfs_attr_leaf_list
7. xfs_attr_list_int_ilocked
8. xfs_attr_list_int
9. xfs_attr_put_listent
10. xfs_attr_list

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (c) 2000-2005 Silicon Graphics, Inc.
   4  * Copyright (c) 2013 Red Hat, Inc.
   5  * All Rights Reserved.
   6  */
   7 #include "xfs.h"
   8 #include "xfs_fs.h"
   9 #include "xfs_shared.h"
  10 #include "xfs_format.h"
  11 #include "xfs_log_format.h"
  12 #include "xfs_trans_resv.h"
  13 #include "xfs_mount.h"
  14 #include "xfs_da_format.h"
  15 #include "xfs_inode.h"
  16 #include "xfs_trans.h"
  17 #include "xfs_bmap.h"
  18 #include "xfs_attr.h"
  19 #include "xfs_attr_sf.h"
  20 #include "xfs_attr_leaf.h"
  21 #include "xfs_error.h"
  22 #include "xfs_trace.h"
  23 #include "xfs_dir2.h"
  24 
  25 STATIC int
  26 xfs_attr_shortform_compare(const void *a, const void *b)
  27 {
  28         xfs_attr_sf_sort_t *sa, *sb;
  29 
  30         sa = (xfs_attr_sf_sort_t *)a;
  31         sb = (xfs_attr_sf_sort_t *)b;
  32         if (sa->hash < sb->hash) {
  33                 return -1;
  34         } else if (sa->hash > sb->hash) {
  35                 return 1;
  36         } else {
  37                 return sa->entno - sb->entno;
  38         }
  39 }
  40 
  41 #define XFS_ISRESET_CURSOR(cursor) \
  42         (!((cursor)->initted) && !((cursor)->hashval) && \
  43          !((cursor)->blkno) && !((cursor)->offset))
  44 /*
  45  * Copy out entries of shortform attribute lists for attr_list().
  46  * Shortform attribute lists are not stored in hashval sorted order.
  47  * If the output buffer is not large enough to hold them all, then we
  48  * we have to calculate each entries' hashvalue and sort them before
  49  * we can begin returning them to the user.
  50  */
  51 static int
  52 xfs_attr_shortform_list(xfs_attr_list_context_t *context)
  53 {
  54         attrlist_cursor_kern_t *cursor;
  55         xfs_attr_sf_sort_t *sbuf, *sbp;
  56         xfs_attr_shortform_t *sf;
  57         xfs_attr_sf_entry_t *sfe;
  58         xfs_inode_t *dp;
  59         int sbsize, nsbuf, count, i;
  60 
  61         ASSERT(context != NULL);
  62         dp = context->dp;
  63         ASSERT(dp != NULL);
  64         ASSERT(dp->i_afp != NULL);
  65         sf = (xfs_attr_shortform_t *)dp->i_afp->if_u1.if_data;
  66         ASSERT(sf != NULL);
  67         if (!sf->hdr.count)
  68                 return 0;
  69         cursor = context->cursor;
  70         ASSERT(cursor != NULL);
  71 
  72         trace_xfs_attr_list_sf(context);
  73 
  74         /*
  75          * If the buffer is large enough and the cursor is at the start,
  76          * do not bother with sorting since we will return everything in
  77          * one buffer and another call using the cursor won't need to be
  78          * made.
  79          * Note the generous fudge factor of 16 overhead bytes per entry.
  80          * If bufsize is zero then put_listent must be a search function
  81          * and can just scan through what we have.
  82          */
  83         if (context->bufsize == 0 ||
  84             (XFS_ISRESET_CURSOR(cursor) &&
  85              (dp->i_afp->if_bytes + sf->hdr.count * 16) < context->bufsize)) {
  86                 for (i = 0, sfe = &sf->list[0]; i < sf->hdr.count; i++) {
  87                         context->put_listent(context,
  88                                              sfe->flags,
  89                                              sfe->nameval,
  90                                              (int)sfe->namelen,
  91                                              (int)sfe->valuelen);
  92                         /*
  93                          * Either search callback finished early or
  94                          * didn't fit it all in the buffer after all.
  95                          */
  96                         if (context->seen_enough)
  97                                 break;
  98                         sfe = XFS_ATTR_SF_NEXTENTRY(sfe);
  99                 }
 100                 trace_xfs_attr_list_sf_all(context);
 101                 return 0;
 102         }
 103 
 104         /* do no more for a search callback */
 105         if (context->bufsize == 0)
 106                 return 0;
 107 
 108         /*
 109          * It didn't all fit, so we have to sort everything on hashval.
 110          */
 111         sbsize = sf->hdr.count * sizeof(*sbuf);
 112         sbp = sbuf = kmem_alloc(sbsize, KM_NOFS);
 113 
 114         /*
 115          * Scan the attribute list for the rest of the entries, storing
 116          * the relevant info from only those that match into a buffer.
 117          */
 118         nsbuf = 0;
 119         for (i = 0, sfe = &sf->list[0]; i < sf->hdr.count; i++) {
 120                 if (unlikely(
 121                     ((char *)sfe < (char *)sf) ||
 122                     ((char *)sfe >= ((char *)sf + dp->i_afp->if_bytes)))) {
 123                         XFS_CORRUPTION_ERROR("xfs_attr_shortform_list",
 124                                              XFS_ERRLEVEL_LOW,
 125                                              context->dp->i_mount, sfe,
 126                                              sizeof(*sfe));
 127                         kmem_free(sbuf);
 128                         return -EFSCORRUPTED;
 129                 }
 130 
 131                 sbp->entno = i;
 132                 sbp->hash = xfs_da_hashname(sfe->nameval, sfe->namelen);
 133                 sbp->name = sfe->nameval;
 134                 sbp->namelen = sfe->namelen;
 135                 /* These are bytes, and both on-disk, don't endian-flip */
 136                 sbp->valuelen = sfe->valuelen;
 137                 sbp->flags = sfe->flags;
 138                 sfe = XFS_ATTR_SF_NEXTENTRY(sfe);
 139                 sbp++;
 140                 nsbuf++;
 141         }
 142 
 143         /*
 144          * Sort the entries on hash then entno.
 145          */
 146         xfs_sort(sbuf, nsbuf, sizeof(*sbuf), xfs_attr_shortform_compare);
 147 
 148         /*
 149          * Re-find our place IN THE SORTED LIST.
 150          */
 151         count = 0;
 152         cursor->initted = 1;
 153         cursor->blkno = 0;
 154         for (sbp = sbuf, i = 0; i < nsbuf; i++, sbp++) {
 155                 if (sbp->hash == cursor->hashval) {
 156                         if (cursor->offset == count) {
 157                                 break;
 158                         }
 159                         count++;
 160                 } else if (sbp->hash > cursor->hashval) {
 161                         break;
 162                 }
 163         }
 164         if (i == nsbuf) {
 165                 kmem_free(sbuf);
 166                 return 0;
 167         }
 168 
 169         /*
 170          * Loop putting entries into the user buffer.
 171          */
 172         for ( ; i < nsbuf; i++, sbp++) {
 173                 if (cursor->hashval != sbp->hash) {
 174                         cursor->hashval = sbp->hash;
 175                         cursor->offset = 0;
 176                 }
 177                 context->put_listent(context,
 178                                      sbp->flags,
 179                                      sbp->name,
 180                                      sbp->namelen,
 181                                      sbp->valuelen);
 182                 if (context->seen_enough)
 183                         break;
 184                 cursor->offset++;
 185         }
 186 
 187         kmem_free(sbuf);
 188         return 0;
 189 }
 190 
 191 /*
 192  * We didn't find the block & hash mentioned in the cursor state, so
 193  * walk down the attr btree looking for the hash.
 194  */
 195 STATIC int
 196 xfs_attr_node_list_lookup(
 197         struct xfs_attr_list_context    *context,
 198         struct attrlist_cursor_kern     *cursor,
 199         struct xfs_buf                  **pbp)
 200 {
 201         struct xfs_da3_icnode_hdr       nodehdr;
 202         struct xfs_da_intnode           *node;
 203         struct xfs_da_node_entry        *btree;
 204         struct xfs_inode                *dp = context->dp;
 205         struct xfs_mount                *mp = dp->i_mount;
 206         struct xfs_trans                *tp = context->tp;
 207         struct xfs_buf                  *bp;
 208         int                             i;
 209         int                             error = 0;
 210         unsigned int                    expected_level = 0;
 211         uint16_t                        magic;
 212 
 213         ASSERT(*pbp == NULL);
 214         cursor->blkno = 0;
 215         for (;;) {
 216                 error = xfs_da3_node_read(tp, dp, cursor->blkno, -1, &bp,
 217                                 XFS_ATTR_FORK);
 218                 if (error)
 219                         return error;
 220                 node = bp->b_addr;
 221                 magic = be16_to_cpu(node->hdr.info.magic);
 222                 if (magic == XFS_ATTR_LEAF_MAGIC ||
 223                     magic == XFS_ATTR3_LEAF_MAGIC)
 224                         break;
 225                 if (magic != XFS_DA_NODE_MAGIC &&
 226                     magic != XFS_DA3_NODE_MAGIC) {
 227                         XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp,
 228                                         node, sizeof(*node));
 229                         goto out_corruptbuf;
 230                 }
 231 
 232                 dp->d_ops->node_hdr_from_disk(&nodehdr, node);
 233 
 234                 /* Tree taller than we can handle; bail out! */
 235                 if (nodehdr.level >= XFS_DA_NODE_MAXDEPTH)
 236                         goto out_corruptbuf;
 237 
 238                 /* Check the level from the root node. */
 239                 if (cursor->blkno == 0)
 240                         expected_level = nodehdr.level - 1;
 241                 else if (expected_level != nodehdr.level)
 242                         goto out_corruptbuf;
 243                 else
 244                         expected_level--;
 245 
 246                 btree = dp->d_ops->node_tree_p(node);
 247                 for (i = 0; i < nodehdr.count; btree++, i++) {
 248                         if (cursor->hashval <= be32_to_cpu(btree->hashval)) {
 249                                 cursor->blkno = be32_to_cpu(btree->before);
 250                                 trace_xfs_attr_list_node_descend(context,
 251                                                 btree);
 252                                 break;
 253                         }
 254                 }
 255                 xfs_trans_brelse(tp, bp);
 256 
 257                 if (i == nodehdr.count)
 258                         return 0;
 259 
 260                 /* We can't point back to the root. */
 261                 if (cursor->blkno == 0)
 262                         return -EFSCORRUPTED;
 263         }
 264 
 265         if (expected_level != 0)
 266                 goto out_corruptbuf;
 267 
 268         *pbp = bp;
 269         return 0;
 270 
 271 out_corruptbuf:
 272         xfs_trans_brelse(tp, bp);
 273         return -EFSCORRUPTED;
 274 }
 275 
 276 STATIC int
 277 xfs_attr_node_list(
 278         struct xfs_attr_list_context    *context)
 279 {
 280         struct xfs_attr3_icleaf_hdr     leafhdr;
 281         struct attrlist_cursor_kern     *cursor;
 282         struct xfs_attr_leafblock       *leaf;
 283         struct xfs_da_intnode           *node;
 284         struct xfs_buf                  *bp;
 285         struct xfs_inode                *dp = context->dp;
 286         struct xfs_mount                *mp = dp->i_mount;
 287         int                             error;
 288 
 289         trace_xfs_attr_node_list(context);
 290 
 291         cursor = context->cursor;
 292         cursor->initted = 1;
 293 
 294         /*
 295          * Do all sorts of validation on the passed-in cursor structure.
 296          * If anything is amiss, ignore the cursor and look up the hashval
 297          * starting from the btree root.
 298          */
 299         bp = NULL;
 300         if (cursor->blkno > 0) {
 301                 error = xfs_da3_node_read(context->tp, dp, cursor->blkno, -1,
 302                                               &bp, XFS_ATTR_FORK);
 303                 if ((error != 0) && (error != -EFSCORRUPTED))
 304                         return error;
 305                 if (bp) {
 306                         struct xfs_attr_leaf_entry *entries;
 307 
 308                         node = bp->b_addr;
 309                         switch (be16_to_cpu(node->hdr.info.magic)) {
 310                         case XFS_DA_NODE_MAGIC:
 311                         case XFS_DA3_NODE_MAGIC:
 312                                 trace_xfs_attr_list_wrong_blk(context);
 313                                 xfs_trans_brelse(context->tp, bp);
 314                                 bp = NULL;
 315                                 break;
 316                         case XFS_ATTR_LEAF_MAGIC:
 317                         case XFS_ATTR3_LEAF_MAGIC:
 318                                 leaf = bp->b_addr;
 319                                 xfs_attr3_leaf_hdr_from_disk(mp->m_attr_geo,
 320                                                              &leafhdr, leaf);
 321                                 entries = xfs_attr3_leaf_entryp(leaf);
 322                                 if (cursor->hashval > be32_to_cpu(
 323                                                 entries[leafhdr.count - 1].hashval)) {
 324                                         trace_xfs_attr_list_wrong_blk(context);
 325                                         xfs_trans_brelse(context->tp, bp);
 326                                         bp = NULL;
 327                                 } else if (cursor->hashval <= be32_to_cpu(
 328                                                 entries[0].hashval)) {
 329                                         trace_xfs_attr_list_wrong_blk(context);
 330                                         xfs_trans_brelse(context->tp, bp);
 331                                         bp = NULL;
 332                                 }
 333                                 break;
 334                         default:
 335                                 trace_xfs_attr_list_wrong_blk(context);
 336                                 xfs_trans_brelse(context->tp, bp);
 337                                 bp = NULL;
 338                         }
 339                 }
 340         }
 341 
 342         /*
 343          * We did not find what we expected given the cursor's contents,
 344          * so we start from the top and work down based on the hash value.
 345          * Note that start of node block is same as start of leaf block.
 346          */
 347         if (bp == NULL) {
 348                 error = xfs_attr_node_list_lookup(context, cursor, &bp);
 349                 if (error || !bp)
 350                         return error;
 351         }
 352         ASSERT(bp != NULL);
 353 
 354         /*
 355          * Roll upward through the blocks, processing each leaf block in
 356          * order.  As long as there is space in the result buffer, keep
 357          * adding the information.
 358          */
 359         for (;;) {
 360                 leaf = bp->b_addr;
 361                 xfs_attr3_leaf_list_int(bp, context);
 362                 xfs_attr3_leaf_hdr_from_disk(mp->m_attr_geo, &leafhdr, leaf);
 363                 if (context->seen_enough || leafhdr.forw == 0)
 364                         break;
 365                 cursor->blkno = leafhdr.forw;
 366                 xfs_trans_brelse(context->tp, bp);
 367                 error = xfs_attr3_leaf_read(context->tp, dp, cursor->blkno, -1, &bp);
 368                 if (error)
 369                         return error;
 370         }
 371         xfs_trans_brelse(context->tp, bp);
 372         return 0;
 373 }
 374 
 375 /*
 376  * Copy out attribute list entries for attr_list(), for leaf attribute lists.
 377  */
 378 void
 379 xfs_attr3_leaf_list_int(
 380         struct xfs_buf                  *bp,
 381         struct xfs_attr_list_context    *context)
 382 {
 383         struct attrlist_cursor_kern     *cursor;
 384         struct xfs_attr_leafblock       *leaf;
 385         struct xfs_attr3_icleaf_hdr     ichdr;
 386         struct xfs_attr_leaf_entry      *entries;
 387         struct xfs_attr_leaf_entry      *entry;
 388         int                             i;
 389         struct xfs_mount                *mp = context->dp->i_mount;
 390 
 391         trace_xfs_attr_list_leaf(context);
 392 
 393         leaf = bp->b_addr;
 394         xfs_attr3_leaf_hdr_from_disk(mp->m_attr_geo, &ichdr, leaf);
 395         entries = xfs_attr3_leaf_entryp(leaf);
 396 
 397         cursor = context->cursor;
 398         cursor->initted = 1;
 399 
 400         /*
 401          * Re-find our place in the leaf block if this is a new syscall.
 402          */
 403         if (context->resynch) {
 404                 entry = &entries[0];
 405                 for (i = 0; i < ichdr.count; entry++, i++) {
 406                         if (be32_to_cpu(entry->hashval) == cursor->hashval) {
 407                                 if (cursor->offset == context->dupcnt) {
 408                                         context->dupcnt = 0;
 409                                         break;
 410                                 }
 411                                 context->dupcnt++;
 412                         } else if (be32_to_cpu(entry->hashval) >
 413                                         cursor->hashval) {
 414                                 context->dupcnt = 0;
 415                                 break;
 416                         }
 417                 }
 418                 if (i == ichdr.count) {
 419                         trace_xfs_attr_list_notfound(context);
 420                         return;
 421                 }
 422         } else {
 423                 entry = &entries[0];
 424                 i = 0;
 425         }
 426         context->resynch = 0;
 427 
 428         /*
 429          * We have found our place, start copying out the new attributes.
 430          */
 431         for (; i < ichdr.count; entry++, i++) {
 432                 char *name;
 433                 int namelen, valuelen;
 434 
 435                 if (be32_to_cpu(entry->hashval) != cursor->hashval) {
 436                         cursor->hashval = be32_to_cpu(entry->hashval);
 437                         cursor->offset = 0;
 438                 }
 439 
 440                 if ((entry->flags & XFS_ATTR_INCOMPLETE) &&
 441                     !(context->flags & ATTR_INCOMPLETE))
 442                         continue;               /* skip incomplete entries */
 443 
 444                 if (entry->flags & XFS_ATTR_LOCAL) {
 445                         xfs_attr_leaf_name_local_t *name_loc;
 446 
 447                         name_loc = xfs_attr3_leaf_name_local(leaf, i);
 448                         name = name_loc->nameval;
 449                         namelen = name_loc->namelen;
 450                         valuelen = be16_to_cpu(name_loc->valuelen);
 451                 } else {
 452                         xfs_attr_leaf_name_remote_t *name_rmt;
 453 
 454                         name_rmt = xfs_attr3_leaf_name_remote(leaf, i);
 455                         name = name_rmt->name;
 456                         namelen = name_rmt->namelen;
 457                         valuelen = be32_to_cpu(name_rmt->valuelen);
 458                 }
 459 
 460                 context->put_listent(context, entry->flags,
 461                                               name, namelen, valuelen);
 462                 if (context->seen_enough)
 463                         break;
 464                 cursor->offset++;
 465         }
 466         trace_xfs_attr_list_leaf_end(context);
 467         return;
 468 }
 469 
 470 /*
 471  * Copy out attribute entries for attr_list(), for leaf attribute lists.
 472  */
 473 STATIC int
 474 xfs_attr_leaf_list(xfs_attr_list_context_t *context)
 475 {
 476         int error;
 477         struct xfs_buf *bp;
 478 
 479         trace_xfs_attr_leaf_list(context);
 480 
 481         context->cursor->blkno = 0;
 482         error = xfs_attr3_leaf_read(context->tp, context->dp, 0, -1, &bp);
 483         if (error)
 484                 return error;
 485 
 486         xfs_attr3_leaf_list_int(bp, context);
 487         xfs_trans_brelse(context->tp, bp);
 488         return 0;
 489 }
 490 
 491 int
 492 xfs_attr_list_int_ilocked(
 493         struct xfs_attr_list_context    *context)
 494 {
 495         struct xfs_inode                *dp = context->dp;
 496 
 497         ASSERT(xfs_isilocked(dp, XFS_ILOCK_SHARED | XFS_ILOCK_EXCL));
 498 
 499         /*
 500          * Decide on what work routines to call based on the inode size.
 501          */
 502         if (!xfs_inode_hasattr(dp))
 503                 return 0;
 504         else if (dp->i_d.di_aformat == XFS_DINODE_FMT_LOCAL)
 505                 return xfs_attr_shortform_list(context);
 506         else if (xfs_bmap_one_block(dp, XFS_ATTR_FORK))
 507                 return xfs_attr_leaf_list(context);
 508         return xfs_attr_node_list(context);
 509 }
 510 
 511 int
 512 xfs_attr_list_int(
 513         xfs_attr_list_context_t *context)
 514 {
 515         int error;
 516         xfs_inode_t *dp = context->dp;
 517         uint            lock_mode;
 518 
 519         XFS_STATS_INC(dp->i_mount, xs_attr_list);
 520 
 521         if (XFS_FORCED_SHUTDOWN(dp->i_mount))
 522                 return -EIO;
 523 
 524         lock_mode = xfs_ilock_attr_map_shared(dp);
 525         error = xfs_attr_list_int_ilocked(context);
 526         xfs_iunlock(dp, lock_mode);
 527         return error;
 528 }
 529 
 530 #define ATTR_ENTBASESIZE                /* minimum bytes used by an attr */ \
 531         (((struct attrlist_ent *) 0)->a_name - (char *) 0)
 532 #define ATTR_ENTSIZE(namelen)           /* actual bytes used by an attr */ \
 533         ((ATTR_ENTBASESIZE + (namelen) + 1 + sizeof(uint32_t)-1) \
 534          & ~(sizeof(uint32_t)-1))
 535 
 536 /*
 537  * Format an attribute and copy it out to the user's buffer.
 538  * Take care to check values and protect against them changing later,
 539  * we may be reading them directly out of a user buffer.
 540  */
 541 STATIC void
 542 xfs_attr_put_listent(
 543         xfs_attr_list_context_t *context,
 544         int             flags,
 545         unsigned char   *name,
 546         int             namelen,
 547         int             valuelen)
 548 {
 549         struct attrlist *alist = (struct attrlist *)context->alist;
 550         attrlist_ent_t *aep;
 551         int arraytop;
 552 
 553         ASSERT(!context->seen_enough);
 554         ASSERT(!(context->flags & ATTR_KERNOVAL));
 555         ASSERT(context->count >= 0);
 556         ASSERT(context->count < (ATTR_MAX_VALUELEN/8));
 557         ASSERT(context->firstu >= sizeof(*alist));
 558         ASSERT(context->firstu <= context->bufsize);
 559 
 560         /*
 561          * Only list entries in the right namespace.
 562          */
 563         if (((context->flags & ATTR_SECURE) == 0) !=
 564             ((flags & XFS_ATTR_SECURE) == 0))
 565                 return;
 566         if (((context->flags & ATTR_ROOT) == 0) !=
 567             ((flags & XFS_ATTR_ROOT) == 0))
 568                 return;
 569 
 570         arraytop = sizeof(*alist) +
 571                         context->count * sizeof(alist->al_offset[0]);
 572         context->firstu -= ATTR_ENTSIZE(namelen);
 573         if (context->firstu < arraytop) {
 574                 trace_xfs_attr_list_full(context);
 575                 alist->al_more = 1;
 576                 context->seen_enough = 1;
 577                 return;
 578         }
 579 
 580         aep = (attrlist_ent_t *)&context->alist[context->firstu];
 581         aep->a_valuelen = valuelen;
 582         memcpy(aep->a_name, name, namelen);
 583         aep->a_name[namelen] = 0;
 584         alist->al_offset[context->count++] = context->firstu;
 585         alist->al_count = context->count;
 586         trace_xfs_attr_list_add(context);
 587         return;
 588 }
 589 
 590 /*
 591  * Generate a list of extended attribute names and optionally
 592  * also value lengths.  Positive return value follows the XFS
 593  * convention of being an error, zero or negative return code
 594  * is the length of the buffer returned (negated), indicating
 595  * success.
 596  */
 597 int
 598 xfs_attr_list(
 599         xfs_inode_t     *dp,
 600         char            *buffer,
 601         int             bufsize,
 602         int             flags,
 603         attrlist_cursor_kern_t *cursor)
 604 {
 605         xfs_attr_list_context_t context;
 606         struct attrlist *alist;
 607         int error;
 608 
 609         /*
 610          * Validate the cursor.
 611          */
 612         if (cursor->pad1 || cursor->pad2)
 613                 return -EINVAL;
 614         if ((cursor->initted == 0) &&
 615             (cursor->hashval || cursor->blkno || cursor->offset))
 616                 return -EINVAL;
 617 
 618         /* Only internal consumers can retrieve incomplete attrs. */
 619         if (flags & ATTR_INCOMPLETE)
 620                 return -EINVAL;
 621 
 622         /*
 623          * Check for a properly aligned buffer.
 624          */
 625         if (((long)buffer) & (sizeof(int)-1))
 626                 return -EFAULT;
 627         if (flags & ATTR_KERNOVAL)
 628                 bufsize = 0;
 629 
 630         /*
 631          * Initialize the output buffer.
 632          */
 633         memset(&context, 0, sizeof(context));
 634         context.dp = dp;
 635         context.cursor = cursor;
 636         context.resynch = 1;
 637         context.flags = flags;
 638         context.alist = buffer;
 639         context.bufsize = (bufsize & ~(sizeof(int)-1));  /* align */
 640         context.firstu = context.bufsize;
 641         context.put_listent = xfs_attr_put_listent;
 642 
 643         alist = (struct attrlist *)context.alist;
 644         alist->al_count = 0;
 645         alist->al_more = 0;
 646         alist->al_offset[0] = context.bufsize;
 647 
 648         error = xfs_attr_list_int(&context);
 649         ASSERT(error <= 0);
 650         return error;
 651 }