fs/xfs/libxfs/xfs_attr_remote.c

   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_bit.h"
  14 #include "xfs_mount.h"
  15 #include "xfs_defer.h"
  16 #include "xfs_da_format.h"
  17 #include "xfs_da_btree.h"
  18 #include "xfs_inode.h"
  19 #include "xfs_alloc.h"
  20 #include "xfs_trans.h"
  21 #include "xfs_inode_item.h"
  22 #include "xfs_bmap.h"
  23 #include "xfs_bmap_util.h"
  24 #include "xfs_attr.h"
  25 #include "xfs_attr_leaf.h"
  26 #include "xfs_attr_remote.h"
  27 #include "xfs_trans_space.h"
  28 #include "xfs_trace.h"
  29 #include "xfs_cksum.h"
  30 #include "xfs_buf_item.h"
  31 #include "xfs_error.h"
  32
  33 #define ATTR_RMTVALUE_MAPSIZE   1       /* # of map entries at once */
  34
  35 /*
  36  * Each contiguous block has a header, so it is not just a simple attribute
  37  * length to FSB conversion.
  38  */
  39 int
  40 xfs_attr3_rmt_blocks(
  41         struct xfs_mount *mp,
  42         int             attrlen)
  43 {
  44         if (xfs_sb_version_hascrc(&mp->m_sb)) {
  45                 int buflen = XFS_ATTR3_RMT_BUF_SPACE(mp, mp->m_sb.sb_blocksize);
  46                 return (attrlen + buflen - 1) / buflen;
  47         }
  48         return XFS_B_TO_FSB(mp, attrlen);
  49 }
  50
  51 /*
  52  * Checking of the remote attribute header is split into two parts. The verifier
  53  * does CRC, location and bounds checking, the unpacking function checks the
  54  * attribute parameters and owner.
  55  */
  56 static xfs_failaddr_t
  57 xfs_attr3_rmt_hdr_ok(
  58         void                    *ptr,
  59         xfs_ino_t               ino,
  60         uint32_t                offset,
  61         uint32_t                size,
  62         xfs_daddr_t             bno)
  63 {
  64         struct xfs_attr3_rmt_hdr *rmt = ptr;
  65
  66         if (bno != be64_to_cpu(rmt->rm_blkno))
  67                 return __this_address;
  68         if (offset != be32_to_cpu(rmt->rm_offset))
  69                 return __this_address;
  70         if (size != be32_to_cpu(rmt->rm_bytes))
  71                 return __this_address;
  72         if (ino != be64_to_cpu(rmt->rm_owner))
  73                 return __this_address;
  74
  75         /* ok */
  76         return NULL;
  77 }
  78
  79 static xfs_failaddr_t
  80 xfs_attr3_rmt_verify(
  81         struct xfs_mount        *mp,
  82         void                    *ptr,
  83         int                     fsbsize,
  84         xfs_daddr_t             bno)
  85 {
  86         struct xfs_attr3_rmt_hdr *rmt = ptr;
  87
  88         if (!xfs_sb_version_hascrc(&mp->m_sb))
  89                 return __this_address;
  90         if (rmt->rm_magic != cpu_to_be32(XFS_ATTR3_RMT_MAGIC))
  91                 return __this_address;
  92         if (!uuid_equal(&rmt->rm_uuid, &mp->m_sb.sb_meta_uuid))
  93                 return __this_address;
  94         if (be64_to_cpu(rmt->rm_blkno) != bno)
  95                 return __this_address;
  96         if (be32_to_cpu(rmt->rm_bytes) > fsbsize - sizeof(*rmt))
  97                 return __this_address;
  98         if (be32_to_cpu(rmt->rm_offset) +
  99                                 be32_to_cpu(rmt->rm_bytes) > XFS_XATTR_SIZE_MAX)
 100                 return __this_address;
 101         if (rmt->rm_owner == 0)
 102                 return __this_address;
 103
 104         return NULL;
 105 }
 106
 107 static int
 108 __xfs_attr3_rmt_read_verify(
 109         struct xfs_buf  *bp,
 110         bool            check_crc,
 111         xfs_failaddr_t  *failaddr)
 112 {
 113         struct xfs_mount *mp = bp->b_target->bt_mount;
 114         char            *ptr;
 115         int             len;
 116         xfs_daddr_t     bno;
 117         int             blksize = mp->m_attr_geo->blksize;
 118
 119         /* no verification of non-crc buffers */
 120         if (!xfs_sb_version_hascrc(&mp->m_sb))
 121                 return 0;
 122
 123         ptr = bp->b_addr;
 124         bno = bp->b_bn;
 125         len = BBTOB(bp->b_length);
 126         ASSERT(len >= blksize);
 127
 128         while (len > 0) {
 129                 if (check_crc &&
 130                     !xfs_verify_cksum(ptr, blksize, XFS_ATTR3_RMT_CRC_OFF)) {
 131                         *failaddr = __this_address;
 132                         return -EFSBADCRC;
 133                 }
 134                 *failaddr = xfs_attr3_rmt_verify(mp, ptr, blksize, bno);
 135                 if (*failaddr)
 136                         return -EFSCORRUPTED;
 137                 len -= blksize;
 138                 ptr += blksize;
 139                 bno += BTOBB(blksize);
 140         }
 141
 142         if (len != 0) {
 143                 *failaddr = __this_address;
 144                 return -EFSCORRUPTED;
 145         }
 146
 147         return 0;
 148 }
 149
 150 static void
 151 xfs_attr3_rmt_read_verify(
 152         struct xfs_buf  *bp)
 153 {
 154         xfs_failaddr_t  fa;
 155         int             error;
 156
 157         error = __xfs_attr3_rmt_read_verify(bp, true, &fa);
 158         if (error)
 159                 xfs_verifier_error(bp, error, fa);
 160 }
 161
 162 static xfs_failaddr_t
 163 xfs_attr3_rmt_verify_struct(
 164         struct xfs_buf  *bp)
 165 {
 166         xfs_failaddr_t  fa;
 167         int             error;
 168
 169         error = __xfs_attr3_rmt_read_verify(bp, false, &fa);
 170         return error ? fa : NULL;
 171 }
 172
 173 static void
 174 xfs_attr3_rmt_write_verify(
 175         struct xfs_buf  *bp)
 176 {
 177         struct xfs_mount *mp = bp->b_target->bt_mount;
 178         xfs_failaddr_t  fa;
 179         int             blksize = mp->m_attr_geo->blksize;
 180         char            *ptr;
 181         int             len;
 182         xfs_daddr_t     bno;
 183
 184         /* no verification of non-crc buffers */
 185         if (!xfs_sb_version_hascrc(&mp->m_sb))
 186                 return;
 187
 188         ptr = bp->b_addr;
 189         bno = bp->b_bn;
 190         len = BBTOB(bp->b_length);
 191         ASSERT(len >= blksize);
 192
 193         while (len > 0) {
 194                 struct xfs_attr3_rmt_hdr *rmt = (struct xfs_attr3_rmt_hdr *)ptr;
 195
 196                 fa = xfs_attr3_rmt_verify(mp, ptr, blksize, bno);
 197                 if (fa) {
 198                         xfs_verifier_error(bp, -EFSCORRUPTED, fa);
 199                         return;
 200                 }
 201
 202                 /*
 203                  * Ensure we aren't writing bogus LSNs to disk. See
 204                  * xfs_attr3_rmt_hdr_set() for the explanation.
 205                  */
 206                 if (rmt->rm_lsn != cpu_to_be64(NULLCOMMITLSN)) {
 207                         xfs_verifier_error(bp, -EFSCORRUPTED, __this_address);
 208                         return;
 209                 }
 210                 xfs_update_cksum(ptr, blksize, XFS_ATTR3_RMT_CRC_OFF);
 211
 212                 len -= blksize;
 213                 ptr += blksize;
 214                 bno += BTOBB(blksize);
 215         }
 216
 217         if (len != 0)
 218                 xfs_verifier_error(bp, -EFSCORRUPTED, __this_address);
 219 }
 220
 221 const struct xfs_buf_ops xfs_attr3_rmt_buf_ops = {
 222         .name = "xfs_attr3_rmt",
 223         .verify_read = xfs_attr3_rmt_read_verify,
 224         .verify_write = xfs_attr3_rmt_write_verify,
 225         .verify_struct = xfs_attr3_rmt_verify_struct,
 226 };
 227
 228 STATIC int
 229 xfs_attr3_rmt_hdr_set(
 230         struct xfs_mount        *mp,
 231         void                    *ptr,
 232         xfs_ino_t               ino,
 233         uint32_t                offset,
 234         uint32_t                size,
 235         xfs_daddr_t             bno)
 236 {
 237         struct xfs_attr3_rmt_hdr *rmt = ptr;
 238
 239         if (!xfs_sb_version_hascrc(&mp->m_sb))
 240                 return 0;
 241
 242         rmt->rm_magic = cpu_to_be32(XFS_ATTR3_RMT_MAGIC);
 243         rmt->rm_offset = cpu_to_be32(offset);
 244         rmt->rm_bytes = cpu_to_be32(size);
 245         uuid_copy(&rmt->rm_uuid, &mp->m_sb.sb_meta_uuid);
 246         rmt->rm_owner = cpu_to_be64(ino);
 247         rmt->rm_blkno = cpu_to_be64(bno);
 248
 249         /*
 250          * Remote attribute blocks are written synchronously, so we don't
 251          * have an LSN that we can stamp in them that makes any sense to log
 252          * recovery. To ensure that log recovery handles overwrites of these
 253          * blocks sanely (i.e. once they've been freed and reallocated as some
 254          * other type of metadata) we need to ensure that the LSN has a value
 255          * that tells log recovery to ignore the LSN and overwrite the buffer
 256          * with whatever is in it's log. To do this, we use the magic
 257          * NULLCOMMITLSN to indicate that the LSN is invalid.
 258          */
 259         rmt->rm_lsn = cpu_to_be64(NULLCOMMITLSN);
 260
 261         return sizeof(struct xfs_attr3_rmt_hdr);
 262 }
 263
 264 /*
 265  * Helper functions to copy attribute data in and out of the one disk extents
 266  */
 267 STATIC int
 268 xfs_attr_rmtval_copyout(
 269         struct xfs_mount *mp,
 270         struct xfs_buf  *bp,
 271         xfs_ino_t       ino,
 272         int             *offset,
 273         int             *valuelen,
 274         uint8_t         **dst)
 275 {
 276         char            *src = bp->b_addr;
 277         xfs_daddr_t     bno = bp->b_bn;
 278         int             len = BBTOB(bp->b_length);
 279         int             blksize = mp->m_attr_geo->blksize;
 280
 281         ASSERT(len >= blksize);
 282
 283         while (len > 0 && *valuelen > 0) {
 284                 int hdr_size = 0;
 285                 int byte_cnt = XFS_ATTR3_RMT_BUF_SPACE(mp, blksize);
 286
 287                 byte_cnt = min(*valuelen, byte_cnt);
 288
 289                 if (xfs_sb_version_hascrc(&mp->m_sb)) {
 290                         if (xfs_attr3_rmt_hdr_ok(src, ino, *offset,
 291                                                   byte_cnt, bno)) {
 292                                 xfs_alert(mp,
 293 "remote attribute header mismatch bno/off/len/owner (0x%llx/0x%x/Ox%x/0x%llx)",
 294                                         bno, *offset, byte_cnt, ino);
 295                                 return -EFSCORRUPTED;
 296                         }
 297                         hdr_size = sizeof(struct xfs_attr3_rmt_hdr);
 298                 }
 299
 300                 memcpy(*dst, src + hdr_size, byte_cnt);
 301
 302                 /* roll buffer forwards */
 303                 len -= blksize;
 304                 src += blksize;
 305                 bno += BTOBB(blksize);
 306
 307                 /* roll attribute data forwards */
 308                 *valuelen -= byte_cnt;
 309                 *dst += byte_cnt;
 310                 *offset += byte_cnt;
 311         }
 312         return 0;
 313 }
 314
 315 STATIC void
 316 xfs_attr_rmtval_copyin(
 317         struct xfs_mount *mp,
 318         struct xfs_buf  *bp,
 319         xfs_ino_t       ino,
 320         int             *offset,
 321         int             *valuelen,
 322         uint8_t         **src)
 323 {
 324         char            *dst = bp->b_addr;
 325         xfs_daddr_t     bno = bp->b_bn;
 326         int             len = BBTOB(bp->b_length);
 327         int             blksize = mp->m_attr_geo->blksize;
 328
 329         ASSERT(len >= blksize);
 330
 331         while (len > 0 && *valuelen > 0) {
 332                 int hdr_size;
 333                 int byte_cnt = XFS_ATTR3_RMT_BUF_SPACE(mp, blksize);
 334
 335                 byte_cnt = min(*valuelen, byte_cnt);
 336                 hdr_size = xfs_attr3_rmt_hdr_set(mp, dst, ino, *offset,
 337                                                  byte_cnt, bno);
 338
 339                 memcpy(dst + hdr_size, *src, byte_cnt);
 340
 341                 /*
 342                  * If this is the last block, zero the remainder of it.
 343                  * Check that we are actually the last block, too.
 344                  */
 345                 if (byte_cnt + hdr_size < blksize) {
 346                         ASSERT(*valuelen - byte_cnt == 0);
 347                         ASSERT(len == blksize);
 348                         memset(dst + hdr_size + byte_cnt, 0,
 349                                         blksize - hdr_size - byte_cnt);
 350                 }
 351
 352                 /* roll buffer forwards */
 353                 len -= blksize;
 354                 dst += blksize;
 355                 bno += BTOBB(blksize);
 356
 357                 /* roll attribute data forwards */
 358                 *valuelen -= byte_cnt;
 359                 *src += byte_cnt;
 360                 *offset += byte_cnt;
 361         }
 362 }
 363
 364 /*
 365  * Read the value associated with an attribute from the out-of-line buffer
 366  * that we stored it in.
 367  */
 368 int
 369 xfs_attr_rmtval_get(
 370         struct xfs_da_args      *args)
 371 {
 372         struct xfs_bmbt_irec    map[ATTR_RMTVALUE_MAPSIZE];
 373         struct xfs_mount        *mp = args->dp->i_mount;
 374         struct xfs_buf          *bp;
 375         xfs_dablk_t             lblkno = args->rmtblkno;
 376         uint8_t                 *dst = args->value;
 377         int                     valuelen;
 378         int                     nmap;
 379         int                     error;
 380         int                     blkcnt = args->rmtblkcnt;
 381         int                     i;
 382         int                     offset = 0;
 383
 384         trace_xfs_attr_rmtval_get(args);
 385
 386         ASSERT(!(args->flags & ATTR_KERNOVAL));
 387         ASSERT(args->rmtvaluelen == args->valuelen);
 388
 389         valuelen = args->rmtvaluelen;
 390         while (valuelen > 0) {
 391                 nmap = ATTR_RMTVALUE_MAPSIZE;
 392                 error = xfs_bmapi_read(args->dp, (xfs_fileoff_t)lblkno,
 393                                        blkcnt, map, &nmap,
 394                                        XFS_BMAPI_ATTRFORK);
 395                 if (error)
 396                         return error;
 397                 ASSERT(nmap >= 1);
 398
 399                 for (i = 0; (i < nmap) && (valuelen > 0); i++) {
 400                         xfs_daddr_t     dblkno;
 401                         int             dblkcnt;
 402
 403                         ASSERT((map[i].br_startblock != DELAYSTARTBLOCK) &&
 404                                (map[i].br_startblock != HOLESTARTBLOCK));
 405                         dblkno = XFS_FSB_TO_DADDR(mp, map[i].br_startblock);
 406                         dblkcnt = XFS_FSB_TO_BB(mp, map[i].br_blockcount);
 407                         error = xfs_trans_read_buf(mp, args->trans,
 408                                                    mp->m_ddev_targp,
 409                                                    dblkno, dblkcnt, 0, &bp,
 410                                                    &xfs_attr3_rmt_buf_ops);
 411                         if (error)
 412                                 return error;
 413
 414                         error = xfs_attr_rmtval_copyout(mp, bp, args->dp->i_ino,
 415                                                         &offset, &valuelen,
 416                                                         &dst);
 417                         xfs_trans_brelse(args->trans, bp);
 418                         if (error)
 419                                 return error;
 420
 421                         /* roll attribute extent map forwards */
 422                         lblkno += map[i].br_blockcount;
 423                         blkcnt -= map[i].br_blockcount;
 424                 }
 425         }
 426         ASSERT(valuelen == 0);
 427         return 0;
 428 }
 429
 430 /*
 431  * Write the value associated with an attribute into the out-of-line buffer
 432  * that we have defined for it.
 433  */
 434 int
 435 xfs_attr_rmtval_set(
 436         struct xfs_da_args      *args)
 437 {
 438         struct xfs_inode        *dp = args->dp;
 439         struct xfs_mount        *mp = dp->i_mount;
 440         struct xfs_bmbt_irec    map;
 441         xfs_dablk_t             lblkno;
 442         xfs_fileoff_t           lfileoff = 0;
 443         uint8_t                 *src = args->value;
 444         int                     blkcnt;
 445         int                     valuelen;
 446         int                     nmap;
 447         int                     error;
 448         int                     offset = 0;
 449
 450         trace_xfs_attr_rmtval_set(args);
 451
 452         /*
 453          * Find a "hole" in the attribute address space large enough for
 454          * us to drop the new attribute's value into. Because CRC enable
 455          * attributes have headers, we can't just do a straight byte to FSB
 456          * conversion and have to take the header space into account.
 457          */
 458         blkcnt = xfs_attr3_rmt_blocks(mp, args->rmtvaluelen);
 459         error = xfs_bmap_first_unused(args->trans, args->dp, blkcnt, &lfileoff,
 460                                                    XFS_ATTR_FORK);
 461         if (error)
 462                 return error;
 463
 464         args->rmtblkno = lblkno = (xfs_dablk_t)lfileoff;
 465         args->rmtblkcnt = blkcnt;
 466
 467         /*
 468          * Roll through the "value", allocating blocks on disk as required.
 469          */
 470         while (blkcnt > 0) {
 471                 /*
 472                  * Allocate a single extent, up to the size of the value.
 473                  *
 474                  * Note that we have to consider this a data allocation as we
 475                  * write the remote attribute without logging the contents.
 476                  * Hence we must ensure that we aren't using blocks that are on
 477                  * the busy list so that we don't overwrite blocks which have
 478                  * recently been freed but their transactions are not yet
 479                  * committed to disk. If we overwrite the contents of a busy
 480                  * extent and then crash then the block may not contain the
 481                  * correct metadata after log recovery occurs.
 482                  */
 483                 nmap = 1;
 484                 error = xfs_bmapi_write(args->trans, dp, (xfs_fileoff_t)lblkno,
 485                                   blkcnt, XFS_BMAPI_ATTRFORK, args->total, &map,
 486                                   &nmap);
 487                 if (error)
 488                         return error;
 489                 error = xfs_defer_finish(&args->trans);
 490                 if (error)
 491                         return error;
 492
 493                 ASSERT(nmap == 1);
 494                 ASSERT((map.br_startblock != DELAYSTARTBLOCK) &&
 495                        (map.br_startblock != HOLESTARTBLOCK));
 496                 lblkno += map.br_blockcount;
 497                 blkcnt -= map.br_blockcount;
 498
 499                 /*
 500                  * Start the next trans in the chain.
 501                  */
 502                 error = xfs_trans_roll_inode(&args->trans, dp);
 503                 if (error)
 504                         return error;
 505         }
 506
 507         /*
 508          * Roll through the "value", copying the attribute value to the
 509          * already-allocated blocks.  Blocks are written synchronously
 510          * so that we can know they are all on disk before we turn off
 511          * the INCOMPLETE flag.
 512          */
 513         lblkno = args->rmtblkno;
 514         blkcnt = args->rmtblkcnt;
 515         valuelen = args->rmtvaluelen;
 516         while (valuelen > 0) {
 517                 struct xfs_buf  *bp;
 518                 xfs_daddr_t     dblkno;
 519                 int             dblkcnt;
 520
 521                 ASSERT(blkcnt > 0);
 522
 523                 nmap = 1;
 524                 error = xfs_bmapi_read(dp, (xfs_fileoff_t)lblkno,
 525                                        blkcnt, &map, &nmap,
 526                                        XFS_BMAPI_ATTRFORK);
 527                 if (error)
 528                         return error;
 529                 ASSERT(nmap == 1);
 530                 ASSERT((map.br_startblock != DELAYSTARTBLOCK) &&
 531                        (map.br_startblock != HOLESTARTBLOCK));
 532
 533                 dblkno = XFS_FSB_TO_DADDR(mp, map.br_startblock),
 534                 dblkcnt = XFS_FSB_TO_BB(mp, map.br_blockcount);
 535
 536                 bp = xfs_buf_get(mp->m_ddev_targp, dblkno, dblkcnt, 0);
 537                 if (!bp)
 538                         return -ENOMEM;
 539                 bp->b_ops = &xfs_attr3_rmt_buf_ops;
 540
 541                 xfs_attr_rmtval_copyin(mp, bp, args->dp->i_ino, &offset,
 542                                        &valuelen, &src);
 543
 544                 error = xfs_bwrite(bp); /* GROT: NOTE: synchronous write */
 545                 xfs_buf_relse(bp);
 546                 if (error)
 547                         return error;
 548
 549
 550                 /* roll attribute extent map forwards */
 551                 lblkno += map.br_blockcount;
 552                 blkcnt -= map.br_blockcount;
 553         }
 554         ASSERT(valuelen == 0);
 555         return 0;
 556 }
 557
 558 /*
 559  * Remove the value associated with an attribute by deleting the
 560  * out-of-line buffer that it is stored on.
 561  */
 562 int
 563 xfs_attr_rmtval_remove(
 564         struct xfs_da_args      *args)
 565 {
 566         struct xfs_mount        *mp = args->dp->i_mount;
 567         xfs_dablk_t             lblkno;
 568         int                     blkcnt;
 569         int                     error;
 570         int                     done;
 571
 572         trace_xfs_attr_rmtval_remove(args);
 573
 574         /*
 575          * Roll through the "value", invalidating the attribute value's blocks.
 576          */
 577         lblkno = args->rmtblkno;
 578         blkcnt = args->rmtblkcnt;
 579         while (blkcnt > 0) {
 580                 struct xfs_bmbt_irec    map;
 581                 struct xfs_buf          *bp;
 582                 xfs_daddr_t             dblkno;
 583                 int                     dblkcnt;
 584                 int                     nmap;
 585
 586                 /*
 587                  * Try to remember where we decided to put the value.
 588                  */
 589                 nmap = 1;
 590                 error = xfs_bmapi_read(args->dp, (xfs_fileoff_t)lblkno,
 591                                        blkcnt, &map, &nmap, XFS_BMAPI_ATTRFORK);
 592                 if (error)
 593                         return error;
 594                 ASSERT(nmap == 1);
 595                 ASSERT((map.br_startblock != DELAYSTARTBLOCK) &&
 596                        (map.br_startblock != HOLESTARTBLOCK));
 597
 598                 dblkno = XFS_FSB_TO_DADDR(mp, map.br_startblock),
 599                 dblkcnt = XFS_FSB_TO_BB(mp, map.br_blockcount);
 600
 601                 /*
 602                  * If the "remote" value is in the cache, remove it.
 603                  */
 604                 bp = xfs_buf_incore(mp->m_ddev_targp, dblkno, dblkcnt, XBF_TRYLOCK);
 605                 if (bp) {
 606                         xfs_buf_stale(bp);
 607                         xfs_buf_relse(bp);
 608                         bp = NULL;
 609                 }
 610
 611                 lblkno += map.br_blockcount;
 612                 blkcnt -= map.br_blockcount;
 613         }
 614
 615         /*
 616          * Keep de-allocating extents until the remote-value region is gone.
 617          */
 618         lblkno = args->rmtblkno;
 619         blkcnt = args->rmtblkcnt;
 620         done = 0;
 621         while (!done) {
 622                 error = xfs_bunmapi(args->trans, args->dp, lblkno, blkcnt,
 623                                     XFS_BMAPI_ATTRFORK, 1, &done);
 624                 if (error)
 625                         return error;
 626                 error = xfs_defer_finish(&args->trans);
 627                 if (error)
 628                         return error;
 629
 630                 /*
 631                  * Close out trans and start the next one in the chain.
 632                  */
 633                 error = xfs_trans_roll_inode(&args->trans, args->dp);
 634                 if (error)
 635                         return error;
 636         }
 637         return 0;
 638 }