kernel/fs/xfs/libxfs/xfs_dir2_data.c

   1 /*
   2  * Copyright (c) 2000-2002,2005 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_format.h"
  22 #include "xfs_log_format.h"
  23 #include "xfs_trans_resv.h"
  24 #include "xfs_mount.h"
  25 #include "xfs_da_format.h"
  26 #include "xfs_da_btree.h"
  27 #include "xfs_inode.h"
  28 #include "xfs_dir2.h"
  29 #include "xfs_dir2_priv.h"
  30 #include "xfs_error.h"
  31 #include "xfs_trans.h"
  32 #include "xfs_buf_item.h"
  33 #include "xfs_cksum.h"
  34 #include "xfs_log.h"
  35
  36 /*
  37  * Check the consistency of the data block.
  38  * The input can also be a block-format directory.
  39  * Return 0 is the buffer is good, otherwise an error.
  40  */
  41 int
  42 __xfs_dir3_data_check(
  43         struct xfs_inode        *dp,            /* incore inode pointer */
  44         struct xfs_buf          *bp)            /* data block's buffer */
  45 {
  46         xfs_dir2_dataptr_t      addr;           /* addr for leaf lookup */
  47         xfs_dir2_data_free_t    *bf;            /* bestfree table */
  48         xfs_dir2_block_tail_t   *btp=NULL;      /* block tail */
  49         int                     count;          /* count of entries found */
  50         xfs_dir2_data_hdr_t     *hdr;           /* data block header */
  51         xfs_dir2_data_entry_t   *dep;           /* data entry */
  52         xfs_dir2_data_free_t    *dfp;           /* bestfree entry */
  53         xfs_dir2_data_unused_t  *dup;           /* unused entry */
  54         char                    *endp;          /* end of useful data */
  55         int                     freeseen;       /* mask of bestfrees seen */
  56         xfs_dahash_t            hash;           /* hash of current name */
  57         int                     i;              /* leaf index */
  58         int                     lastfree;       /* last entry was unused */
  59         xfs_dir2_leaf_entry_t   *lep=NULL;      /* block leaf entries */
  60         xfs_mount_t             *mp;            /* filesystem mount point */
  61         char                    *p;             /* current data position */
  62         int                     stale;          /* count of stale leaves */
  63         struct xfs_name         name;
  64         const struct xfs_dir_ops *ops;
  65         struct xfs_da_geometry  *geo;
  66
  67         mp = bp->b_target->bt_mount;
  68         geo = mp->m_dir_geo;
  69
  70         /*
  71          * We can be passed a null dp here from a verifier, so we need to go the
  72          * hard way to get them.
  73          */
  74         ops = xfs_dir_get_ops(mp, dp);
  75
  76         hdr = bp->b_addr;
  77         p = (char *)ops->data_entry_p(hdr);
  78
  79         switch (hdr->magic) {
  80         case cpu_to_be32(XFS_DIR3_BLOCK_MAGIC):
  81         case cpu_to_be32(XFS_DIR2_BLOCK_MAGIC):
  82                 btp = xfs_dir2_block_tail_p(geo, hdr);
  83                 lep = xfs_dir2_block_leaf_p(btp);
  84                 endp = (char *)lep;
  85
  86                 /*
  87                  * The number of leaf entries is limited by the size of the
  88                  * block and the amount of space used by the data entries.
  89                  * We don't know how much space is used by the data entries yet,
  90                  * so just ensure that the count falls somewhere inside the
  91                  * block right now.
  92                  */
  93                 XFS_WANT_CORRUPTED_RETURN(mp, be32_to_cpu(btp->count) <
  94                         ((char *)btp - p) / sizeof(struct xfs_dir2_leaf_entry));
  95                 break;
  96         case cpu_to_be32(XFS_DIR3_DATA_MAGIC):
  97         case cpu_to_be32(XFS_DIR2_DATA_MAGIC):
  98                 endp = (char *)hdr + geo->blksize;
  99                 break;
 100         default:
 101                 XFS_ERROR_REPORT("Bad Magic", XFS_ERRLEVEL_LOW, mp);
 102                 return -EFSCORRUPTED;
 103         }
 104
 105         /*
 106          * Account for zero bestfree entries.
 107          */
 108         bf = ops->data_bestfree_p(hdr);
 109         count = lastfree = freeseen = 0;
 110         if (!bf[0].length) {
 111                 XFS_WANT_CORRUPTED_RETURN(mp, !bf[0].offset);
 112                 freeseen |= 1 << 0;
 113         }
 114         if (!bf[1].length) {
 115                 XFS_WANT_CORRUPTED_RETURN(mp, !bf[1].offset);
 116                 freeseen |= 1 << 1;
 117         }
 118         if (!bf[2].length) {
 119                 XFS_WANT_CORRUPTED_RETURN(mp, !bf[2].offset);
 120                 freeseen |= 1 << 2;
 121         }
 122
 123         XFS_WANT_CORRUPTED_RETURN(mp, be16_to_cpu(bf[0].length) >=
 124                                                 be16_to_cpu(bf[1].length));
 125         XFS_WANT_CORRUPTED_RETURN(mp, be16_to_cpu(bf[1].length) >=
 126                                                 be16_to_cpu(bf[2].length));
 127         /*
 128          * Loop over the data/unused entries.
 129          */
 130         while (p < endp) {
 131                 dup = (xfs_dir2_data_unused_t *)p;
 132                 /*
 133                  * If it's unused, look for the space in the bestfree table.
 134                  * If we find it, account for that, else make sure it
 135                  * doesn't need to be there.
 136                  */
 137                 if (be16_to_cpu(dup->freetag) == XFS_DIR2_DATA_FREE_TAG) {
 138                         XFS_WANT_CORRUPTED_RETURN(mp, lastfree == 0);
 139                         XFS_WANT_CORRUPTED_RETURN(mp,
 140                                 be16_to_cpu(*xfs_dir2_data_unused_tag_p(dup)) ==
 141                                                (char *)dup - (char *)hdr);
 142                         dfp = xfs_dir2_data_freefind(hdr, bf, dup);
 143                         if (dfp) {
 144                                 i = (int)(dfp - bf);
 145                                 XFS_WANT_CORRUPTED_RETURN(mp,
 146                                         (freeseen & (1 << i)) == 0);
 147                                 freeseen |= 1 << i;
 148                         } else {
 149                                 XFS_WANT_CORRUPTED_RETURN(mp,
 150                                         be16_to_cpu(dup->length) <=
 151                                                 be16_to_cpu(bf[2].length));
 152                         }
 153                         p += be16_to_cpu(dup->length);
 154                         lastfree = 1;
 155                         continue;
 156                 }
 157                 /*
 158                  * It's a real entry.  Validate the fields.
 159                  * If this is a block directory then make sure it's
 160                  * in the leaf section of the block.
 161                  * The linear search is crude but this is DEBUG code.
 162                  */
 163                 dep = (xfs_dir2_data_entry_t *)p;
 164                 XFS_WANT_CORRUPTED_RETURN(mp, dep->namelen != 0);
 165                 XFS_WANT_CORRUPTED_RETURN(mp,
 166                         !xfs_dir_ino_validate(mp, be64_to_cpu(dep->inumber)));
 167                 XFS_WANT_CORRUPTED_RETURN(mp,
 168                         be16_to_cpu(*ops->data_entry_tag_p(dep)) ==
 169                                                (char *)dep - (char *)hdr);
 170                 XFS_WANT_CORRUPTED_RETURN(mp,
 171                                 ops->data_get_ftype(dep) < XFS_DIR3_FT_MAX);
 172                 count++;
 173                 lastfree = 0;
 174                 if (hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
 175                     hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC)) {
 176                         addr = xfs_dir2_db_off_to_dataptr(geo, geo->datablk,
 177                                                 (xfs_dir2_data_aoff_t)
 178                                                 ((char *)dep - (char *)hdr));
 179                         name.name = dep->name;
 180                         name.len = dep->namelen;
 181                         hash = mp->m_dirnameops->hashname(&name);
 182                         for (i = 0; i < be32_to_cpu(btp->count); i++) {
 183                                 if (be32_to_cpu(lep[i].address) == addr &&
 184                                     be32_to_cpu(lep[i].hashval) == hash)
 185                                         break;
 186                         }
 187                         XFS_WANT_CORRUPTED_RETURN(mp,
 188                                                   i < be32_to_cpu(btp->count));
 189                 }
 190                 p += ops->data_entsize(dep->namelen);
 191         }
 192         /*
 193          * Need to have seen all the entries and all the bestfree slots.
 194          */
 195         XFS_WANT_CORRUPTED_RETURN(mp, freeseen == 7);
 196         if (hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
 197             hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC)) {
 198                 for (i = stale = 0; i < be32_to_cpu(btp->count); i++) {
 199                         if (lep[i].address ==
 200                             cpu_to_be32(XFS_DIR2_NULL_DATAPTR))
 201                                 stale++;
 202                         if (i > 0)
 203                                 XFS_WANT_CORRUPTED_RETURN(mp,
 204                                         be32_to_cpu(lep[i].hashval) >=
 205                                                 be32_to_cpu(lep[i - 1].hashval));
 206                 }
 207                 XFS_WANT_CORRUPTED_RETURN(mp, count ==
 208                         be32_to_cpu(btp->count) - be32_to_cpu(btp->stale));
 209                 XFS_WANT_CORRUPTED_RETURN(mp, stale == be32_to_cpu(btp->stale));
 210         }
 211         return 0;
 212 }
 213
 214 static bool
 215 xfs_dir3_data_verify(
 216         struct xfs_buf          *bp)
 217 {
 218         struct xfs_mount        *mp = bp->b_target->bt_mount;
 219         struct xfs_dir3_blk_hdr *hdr3 = bp->b_addr;
 220
 221         if (xfs_sb_version_hascrc(&mp->m_sb)) {
 222                 if (hdr3->magic != cpu_to_be32(XFS_DIR3_DATA_MAGIC))
 223                         return false;
 224                 if (!uuid_equal(&hdr3->uuid, &mp->m_sb.sb_meta_uuid))
 225                         return false;
 226                 if (be64_to_cpu(hdr3->blkno) != bp->b_bn)
 227                         return false;
 228                 if (!xfs_log_check_lsn(mp, be64_to_cpu(hdr3->lsn)))
 229                         return false;
 230         } else {
 231                 if (hdr3->magic != cpu_to_be32(XFS_DIR2_DATA_MAGIC))
 232                         return false;
 233         }
 234         if (__xfs_dir3_data_check(NULL, bp))
 235                 return false;
 236         return true;
 237 }
 238
 239 /*
 240  * Readahead of the first block of the directory when it is opened is completely
 241  * oblivious to the format of the directory. Hence we can either get a block
 242  * format buffer or a data format buffer on readahead.
 243  */
 244 static void
 245 xfs_dir3_data_reada_verify(
 246         struct xfs_buf          *bp)
 247 {
 248         struct xfs_dir2_data_hdr *hdr = bp->b_addr;
 249
 250         switch (hdr->magic) {
 251         case cpu_to_be32(XFS_DIR2_BLOCK_MAGIC):
 252         case cpu_to_be32(XFS_DIR3_BLOCK_MAGIC):
 253                 bp->b_ops = &xfs_dir3_block_buf_ops;
 254                 bp->b_ops->verify_read(bp);
 255                 return;
 256         case cpu_to_be32(XFS_DIR2_DATA_MAGIC):
 257         case cpu_to_be32(XFS_DIR3_DATA_MAGIC):
 258                 bp->b_ops = &xfs_dir3_data_buf_ops;
 259                 bp->b_ops->verify_read(bp);
 260                 return;
 261         default:
 262                 xfs_buf_ioerror(bp, -EFSCORRUPTED);
 263                 xfs_verifier_error(bp);
 264                 break;
 265         }
 266 }
 267
 268 static void
 269 xfs_dir3_data_read_verify(
 270         struct xfs_buf  *bp)
 271 {
 272         struct xfs_mount        *mp = bp->b_target->bt_mount;
 273
 274         if (xfs_sb_version_hascrc(&mp->m_sb) &&
 275              !xfs_buf_verify_cksum(bp, XFS_DIR3_DATA_CRC_OFF))
 276                  xfs_buf_ioerror(bp, -EFSBADCRC);
 277         else if (!xfs_dir3_data_verify(bp))
 278                 xfs_buf_ioerror(bp, -EFSCORRUPTED);
 279
 280         if (bp->b_error)
 281                 xfs_verifier_error(bp);
 282 }
 283
 284 static void
 285 xfs_dir3_data_write_verify(
 286         struct xfs_buf  *bp)
 287 {
 288         struct xfs_mount        *mp = bp->b_target->bt_mount;
 289         struct xfs_buf_log_item *bip = bp->b_fspriv;
 290         struct xfs_dir3_blk_hdr *hdr3 = bp->b_addr;
 291
 292         if (!xfs_dir3_data_verify(bp)) {
 293                 xfs_buf_ioerror(bp, -EFSCORRUPTED);
 294                 xfs_verifier_error(bp);
 295                 return;
 296         }
 297
 298         if (!xfs_sb_version_hascrc(&mp->m_sb))
 299                 return;
 300
 301         if (bip)
 302                 hdr3->lsn = cpu_to_be64(bip->bli_item.li_lsn);
 303
 304         xfs_buf_update_cksum(bp, XFS_DIR3_DATA_CRC_OFF);
 305 }
 306
 307 const struct xfs_buf_ops xfs_dir3_data_buf_ops = {
 308         .name = "xfs_dir3_data",
 309         .verify_read = xfs_dir3_data_read_verify,
 310         .verify_write = xfs_dir3_data_write_verify,
 311 };
 312
 313 static const struct xfs_buf_ops xfs_dir3_data_reada_buf_ops = {
 314         .name = "xfs_dir3_data_reada",
 315         .verify_read = xfs_dir3_data_reada_verify,
 316         .verify_write = xfs_dir3_data_write_verify,
 317 };
 318
 319
 320 int
 321 xfs_dir3_data_read(
 322         struct xfs_trans        *tp,
 323         struct xfs_inode        *dp,
 324         xfs_dablk_t             bno,
 325         xfs_daddr_t             mapped_bno,
 326         struct xfs_buf          **bpp)
 327 {
 328         int                     err;
 329
 330         err = xfs_da_read_buf(tp, dp, bno, mapped_bno, bpp,
 331                                 XFS_DATA_FORK, &xfs_dir3_data_buf_ops);
 332         if (!err && tp)
 333                 xfs_trans_buf_set_type(tp, *bpp, XFS_BLFT_DIR_DATA_BUF);
 334         return err;
 335 }
 336
 337 int
 338 xfs_dir3_data_readahead(
 339         struct xfs_inode        *dp,
 340         xfs_dablk_t             bno,
 341         xfs_daddr_t             mapped_bno)
 342 {
 343         return xfs_da_reada_buf(dp, bno, mapped_bno,
 344                                 XFS_DATA_FORK, &xfs_dir3_data_reada_buf_ops);
 345 }
 346
 347 /*
 348  * Given a data block and an unused entry from that block,
 349  * return the bestfree entry if any that corresponds to it.
 350  */
 351 xfs_dir2_data_free_t *
 352 xfs_dir2_data_freefind(
 353         struct xfs_dir2_data_hdr *hdr,          /* data block header */
 354         struct xfs_dir2_data_free *bf,          /* bestfree table pointer */
 355         struct xfs_dir2_data_unused *dup)       /* unused space */
 356 {
 357         xfs_dir2_data_free_t    *dfp;           /* bestfree entry */
 358         xfs_dir2_data_aoff_t    off;            /* offset value needed */
 359 #ifdef DEBUG
 360         int                     matched;        /* matched the value */
 361         int                     seenzero;       /* saw a 0 bestfree entry */
 362 #endif
 363
 364         off = (xfs_dir2_data_aoff_t)((char *)dup - (char *)hdr);
 365
 366 #ifdef DEBUG
 367         /*
 368          * Validate some consistency in the bestfree table.
 369          * Check order, non-overlapping entries, and if we find the
 370          * one we're looking for it has to be exact.
 371          */
 372         ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
 373                hdr->magic == cpu_to_be32(XFS_DIR3_DATA_MAGIC) ||
 374                hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
 375                hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC));
 376         for (dfp = &bf[0], seenzero = matched = 0;
 377              dfp < &bf[XFS_DIR2_DATA_FD_COUNT];
 378              dfp++) {
 379                 if (!dfp->offset) {
 380                         ASSERT(!dfp->length);
 381                         seenzero = 1;
 382                         continue;
 383                 }
 384                 ASSERT(seenzero == 0);
 385                 if (be16_to_cpu(dfp->offset) == off) {
 386                         matched = 1;
 387                         ASSERT(dfp->length == dup->length);
 388                 } else if (off < be16_to_cpu(dfp->offset))
 389                         ASSERT(off + be16_to_cpu(dup->length) <= be16_to_cpu(dfp->offset));
 390                 else
 391                         ASSERT(be16_to_cpu(dfp->offset) + be16_to_cpu(dfp->length) <= off);
 392                 ASSERT(matched || be16_to_cpu(dfp->length) >= be16_to_cpu(dup->length));
 393                 if (dfp > &bf[0])
 394                         ASSERT(be16_to_cpu(dfp[-1].length) >= be16_to_cpu(dfp[0].length));
 395         }
 396 #endif
 397         /*
 398          * If this is smaller than the smallest bestfree entry,
 399          * it can't be there since they're sorted.
 400          */
 401         if (be16_to_cpu(dup->length) <
 402             be16_to_cpu(bf[XFS_DIR2_DATA_FD_COUNT - 1].length))
 403                 return NULL;
 404         /*
 405          * Look at the three bestfree entries for our guy.
 406          */
 407         for (dfp = &bf[0]; dfp < &bf[XFS_DIR2_DATA_FD_COUNT]; dfp++) {
 408                 if (!dfp->offset)
 409                         return NULL;
 410                 if (be16_to_cpu(dfp->offset) == off)
 411                         return dfp;
 412         }
 413         /*
 414          * Didn't find it.  This only happens if there are duplicate lengths.
 415          */
 416         return NULL;
 417 }
 418
 419 /*
 420  * Insert an unused-space entry into the bestfree table.
 421  */
 422 xfs_dir2_data_free_t *                          /* entry inserted */
 423 xfs_dir2_data_freeinsert(
 424         struct xfs_dir2_data_hdr *hdr,          /* data block pointer */
 425         struct xfs_dir2_data_free *dfp,         /* bestfree table pointer */
 426         struct xfs_dir2_data_unused *dup,       /* unused space */
 427         int                     *loghead)       /* log the data header (out) */
 428 {
 429         xfs_dir2_data_free_t    new;            /* new bestfree entry */
 430
 431         ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
 432                hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
 433                hdr->magic == cpu_to_be32(XFS_DIR3_DATA_MAGIC) ||
 434                hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC));
 435
 436         new.length = dup->length;
 437         new.offset = cpu_to_be16((char *)dup - (char *)hdr);
 438
 439         /*
 440          * Insert at position 0, 1, or 2; or not at all.
 441          */
 442         if (be16_to_cpu(new.length) > be16_to_cpu(dfp[0].length)) {
 443                 dfp[2] = dfp[1];
 444                 dfp[1] = dfp[0];
 445                 dfp[0] = new;
 446                 *loghead = 1;
 447                 return &dfp[0];
 448         }
 449         if (be16_to_cpu(new.length) > be16_to_cpu(dfp[1].length)) {
 450                 dfp[2] = dfp[1];
 451                 dfp[1] = new;
 452                 *loghead = 1;
 453                 return &dfp[1];
 454         }
 455         if (be16_to_cpu(new.length) > be16_to_cpu(dfp[2].length)) {
 456                 dfp[2] = new;
 457                 *loghead = 1;
 458                 return &dfp[2];
 459         }
 460         return NULL;
 461 }
 462
 463 /*
 464  * Remove a bestfree entry from the table.
 465  */
 466 STATIC void
 467 xfs_dir2_data_freeremove(
 468         struct xfs_dir2_data_hdr *hdr,          /* data block header */
 469         struct xfs_dir2_data_free *bf,          /* bestfree table pointer */
 470         struct xfs_dir2_data_free *dfp,         /* bestfree entry pointer */
 471         int                     *loghead)       /* out: log data header */
 472 {
 473
 474         ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
 475                hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
 476                hdr->magic == cpu_to_be32(XFS_DIR3_DATA_MAGIC) ||
 477                hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC));
 478
 479         /*
 480          * It's the first entry, slide the next 2 up.
 481          */
 482         if (dfp == &bf[0]) {
 483                 bf[0] = bf[1];
 484                 bf[1] = bf[2];
 485         }
 486         /*
 487          * It's the second entry, slide the 3rd entry up.
 488          */
 489         else if (dfp == &bf[1])
 490                 bf[1] = bf[2];
 491         /*
 492          * Must be the last entry.
 493          */
 494         else
 495                 ASSERT(dfp == &bf[2]);
 496         /*
 497          * Clear the 3rd entry, must be zero now.
 498          */
 499         bf[2].length = 0;
 500         bf[2].offset = 0;
 501         *loghead = 1;
 502 }
 503
 504 /*
 505  * Given a data block, reconstruct its bestfree map.
 506  */
 507 void
 508 xfs_dir2_data_freescan(
 509         struct xfs_inode        *dp,
 510         struct xfs_dir2_data_hdr *hdr,
 511         int                     *loghead)
 512 {
 513         xfs_dir2_block_tail_t   *btp;           /* block tail */
 514         xfs_dir2_data_entry_t   *dep;           /* active data entry */
 515         xfs_dir2_data_unused_t  *dup;           /* unused data entry */
 516         struct xfs_dir2_data_free *bf;
 517         char                    *endp;          /* end of block's data */
 518         char                    *p;             /* current entry pointer */
 519         struct xfs_da_geometry  *geo = dp->i_mount->m_dir_geo;
 520
 521         ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
 522                hdr->magic == cpu_to_be32(XFS_DIR3_DATA_MAGIC) ||
 523                hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
 524                hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC));
 525
 526         /*
 527          * Start by clearing the table.
 528          */
 529         bf = dp->d_ops->data_bestfree_p(hdr);
 530         memset(bf, 0, sizeof(*bf) * XFS_DIR2_DATA_FD_COUNT);
 531         *loghead = 1;
 532         /*
 533          * Set up pointers.
 534          */
 535         p = (char *)dp->d_ops->data_entry_p(hdr);
 536         if (hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
 537             hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC)) {
 538                 btp = xfs_dir2_block_tail_p(geo, hdr);
 539                 endp = (char *)xfs_dir2_block_leaf_p(btp);
 540         } else
 541                 endp = (char *)hdr + geo->blksize;
 542         /*
 543          * Loop over the block's entries.
 544          */
 545         while (p < endp) {
 546                 dup = (xfs_dir2_data_unused_t *)p;
 547                 /*
 548                  * If it's a free entry, insert it.
 549                  */
 550                 if (be16_to_cpu(dup->freetag) == XFS_DIR2_DATA_FREE_TAG) {
 551                         ASSERT((char *)dup - (char *)hdr ==
 552                                be16_to_cpu(*xfs_dir2_data_unused_tag_p(dup)));
 553                         xfs_dir2_data_freeinsert(hdr, bf, dup, loghead);
 554                         p += be16_to_cpu(dup->length);
 555                 }
 556                 /*
 557                  * For active entries, check their tags and skip them.
 558                  */
 559                 else {
 560                         dep = (xfs_dir2_data_entry_t *)p;
 561                         ASSERT((char *)dep - (char *)hdr ==
 562                                be16_to_cpu(*dp->d_ops->data_entry_tag_p(dep)));
 563                         p += dp->d_ops->data_entsize(dep->namelen);
 564                 }
 565         }
 566 }
 567
 568 /*
 569  * Initialize a data block at the given block number in the directory.
 570  * Give back the buffer for the created block.
 571  */
 572 int                                             /* error */
 573 xfs_dir3_data_init(
 574         xfs_da_args_t           *args,          /* directory operation args */
 575         xfs_dir2_db_t           blkno,          /* logical dir block number */
 576         struct xfs_buf          **bpp)          /* output block buffer */
 577 {
 578         struct xfs_buf          *bp;            /* block buffer */
 579         xfs_dir2_data_hdr_t     *hdr;           /* data block header */
 580         xfs_inode_t             *dp;            /* incore directory inode */
 581         xfs_dir2_data_unused_t  *dup;           /* unused entry pointer */
 582         struct xfs_dir2_data_free *bf;
 583         int                     error;          /* error return value */
 584         int                     i;              /* bestfree index */
 585         xfs_mount_t             *mp;            /* filesystem mount point */
 586         xfs_trans_t             *tp;            /* transaction pointer */
 587         int                     t;              /* temp */
 588
 589         dp = args->dp;
 590         mp = dp->i_mount;
 591         tp = args->trans;
 592         /*
 593          * Get the buffer set up for the block.
 594          */
 595         error = xfs_da_get_buf(tp, dp, xfs_dir2_db_to_da(args->geo, blkno),
 596                                -1, &bp, XFS_DATA_FORK);
 597         if (error)
 598                 return error;
 599         bp->b_ops = &xfs_dir3_data_buf_ops;
 600         xfs_trans_buf_set_type(tp, bp, XFS_BLFT_DIR_DATA_BUF);
 601
 602         /*
 603          * Initialize the header.
 604          */
 605         hdr = bp->b_addr;
 606         if (xfs_sb_version_hascrc(&mp->m_sb)) {
 607                 struct xfs_dir3_blk_hdr *hdr3 = bp->b_addr;
 608
 609                 memset(hdr3, 0, sizeof(*hdr3));
 610                 hdr3->magic = cpu_to_be32(XFS_DIR3_DATA_MAGIC);
 611                 hdr3->blkno = cpu_to_be64(bp->b_bn);
 612                 hdr3->owner = cpu_to_be64(dp->i_ino);
 613                 uuid_copy(&hdr3->uuid, &mp->m_sb.sb_meta_uuid);
 614
 615         } else
 616                 hdr->magic = cpu_to_be32(XFS_DIR2_DATA_MAGIC);
 617
 618         bf = dp->d_ops->data_bestfree_p(hdr);
 619         bf[0].offset = cpu_to_be16(dp->d_ops->data_entry_offset);
 620         for (i = 1; i < XFS_DIR2_DATA_FD_COUNT; i++) {
 621                 bf[i].length = 0;
 622                 bf[i].offset = 0;
 623         }
 624
 625         /*
 626          * Set up an unused entry for the block's body.
 627          */
 628         dup = dp->d_ops->data_unused_p(hdr);
 629         dup->freetag = cpu_to_be16(XFS_DIR2_DATA_FREE_TAG);
 630
 631         t = args->geo->blksize - (uint)dp->d_ops->data_entry_offset;
 632         bf[0].length = cpu_to_be16(t);
 633         dup->length = cpu_to_be16(t);
 634         *xfs_dir2_data_unused_tag_p(dup) = cpu_to_be16((char *)dup - (char *)hdr);
 635         /*
 636          * Log it and return it.
 637          */
 638         xfs_dir2_data_log_header(args, bp);
 639         xfs_dir2_data_log_unused(args, bp, dup);
 640         *bpp = bp;
 641         return 0;
 642 }
 643
 644 /*
 645  * Log an active data entry from the block.
 646  */
 647 void
 648 xfs_dir2_data_log_entry(
 649         struct xfs_da_args      *args,
 650         struct xfs_buf          *bp,
 651         xfs_dir2_data_entry_t   *dep)           /* data entry pointer */
 652 {
 653         struct xfs_dir2_data_hdr *hdr = bp->b_addr;
 654
 655         ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
 656                hdr->magic == cpu_to_be32(XFS_DIR3_DATA_MAGIC) ||
 657                hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
 658                hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC));
 659
 660         xfs_trans_log_buf(args->trans, bp, (uint)((char *)dep - (char *)hdr),
 661                 (uint)((char *)(args->dp->d_ops->data_entry_tag_p(dep) + 1) -
 662                        (char *)hdr - 1));
 663 }
 664
 665 /*
 666  * Log a data block header.
 667  */
 668 void
 669 xfs_dir2_data_log_header(
 670         struct xfs_da_args      *args,
 671         struct xfs_buf          *bp)
 672 {
 673 #ifdef DEBUG
 674         struct xfs_dir2_data_hdr *hdr = bp->b_addr;
 675
 676         ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
 677                hdr->magic == cpu_to_be32(XFS_DIR3_DATA_MAGIC) ||
 678                hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
 679                hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC));
 680 #endif
 681
 682         xfs_trans_log_buf(args->trans, bp, 0,
 683                           args->dp->d_ops->data_entry_offset - 1);
 684 }
 685
 686 /*
 687  * Log a data unused entry.
 688  */
 689 void
 690 xfs_dir2_data_log_unused(
 691         struct xfs_da_args      *args,
 692         struct xfs_buf          *bp,
 693         xfs_dir2_data_unused_t  *dup)           /* data unused pointer */
 694 {
 695         xfs_dir2_data_hdr_t     *hdr = bp->b_addr;
 696
 697         ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
 698                hdr->magic == cpu_to_be32(XFS_DIR3_DATA_MAGIC) ||
 699                hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
 700                hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC));
 701
 702         /*
 703          * Log the first part of the unused entry.
 704          */
 705         xfs_trans_log_buf(args->trans, bp, (uint)((char *)dup - (char *)hdr),
 706                 (uint)((char *)&dup->length + sizeof(dup->length) -
 707                        1 - (char *)hdr));
 708         /*
 709          * Log the end (tag) of the unused entry.
 710          */
 711         xfs_trans_log_buf(args->trans, bp,
 712                 (uint)((char *)xfs_dir2_data_unused_tag_p(dup) - (char *)hdr),
 713                 (uint)((char *)xfs_dir2_data_unused_tag_p(dup) - (char *)hdr +
 714                        sizeof(xfs_dir2_data_off_t) - 1));
 715 }
 716
 717 /*
 718  * Make a byte range in the data block unused.
 719  * Its current contents are unimportant.
 720  */
 721 void
 722 xfs_dir2_data_make_free(
 723         struct xfs_da_args      *args,
 724         struct xfs_buf          *bp,
 725         xfs_dir2_data_aoff_t    offset,         /* starting byte offset */
 726         xfs_dir2_data_aoff_t    len,            /* length in bytes */
 727         int                     *needlogp,      /* out: log header */
 728         int                     *needscanp)     /* out: regen bestfree */
 729 {
 730         xfs_dir2_data_hdr_t     *hdr;           /* data block pointer */
 731         xfs_dir2_data_free_t    *dfp;           /* bestfree pointer */
 732         char                    *endptr;        /* end of data area */
 733         int                     needscan;       /* need to regen bestfree */
 734         xfs_dir2_data_unused_t  *newdup;        /* new unused entry */
 735         xfs_dir2_data_unused_t  *postdup;       /* unused entry after us */
 736         xfs_dir2_data_unused_t  *prevdup;       /* unused entry before us */
 737         struct xfs_dir2_data_free *bf;
 738
 739         hdr = bp->b_addr;
 740
 741         /*
 742          * Figure out where the end of the data area is.
 743          */
 744         if (hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
 745             hdr->magic == cpu_to_be32(XFS_DIR3_DATA_MAGIC))
 746                 endptr = (char *)hdr + args->geo->blksize;
 747         else {
 748                 xfs_dir2_block_tail_t   *btp;   /* block tail */
 749
 750                 ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
 751                         hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC));
 752                 btp = xfs_dir2_block_tail_p(args->geo, hdr);
 753                 endptr = (char *)xfs_dir2_block_leaf_p(btp);
 754         }
 755         /*
 756          * If this isn't the start of the block, then back up to
 757          * the previous entry and see if it's free.
 758          */
 759         if (offset > args->dp->d_ops->data_entry_offset) {
 760                 __be16                  *tagp;  /* tag just before us */
 761
 762                 tagp = (__be16 *)((char *)hdr + offset) - 1;
 763                 prevdup = (xfs_dir2_data_unused_t *)((char *)hdr + be16_to_cpu(*tagp));
 764                 if (be16_to_cpu(prevdup->freetag) != XFS_DIR2_DATA_FREE_TAG)
 765                         prevdup = NULL;
 766         } else
 767                 prevdup = NULL;
 768         /*
 769          * If this isn't the end of the block, see if the entry after
 770          * us is free.
 771          */
 772         if ((char *)hdr + offset + len < endptr) {
 773                 postdup =
 774                         (xfs_dir2_data_unused_t *)((char *)hdr + offset + len);
 775                 if (be16_to_cpu(postdup->freetag) != XFS_DIR2_DATA_FREE_TAG)
 776                         postdup = NULL;
 777         } else
 778                 postdup = NULL;
 779         ASSERT(*needscanp == 0);
 780         needscan = 0;
 781         /*
 782          * Previous and following entries are both free,
 783          * merge everything into a single free entry.
 784          */
 785         bf = args->dp->d_ops->data_bestfree_p(hdr);
 786         if (prevdup && postdup) {
 787                 xfs_dir2_data_free_t    *dfp2;  /* another bestfree pointer */
 788
 789                 /*
 790                  * See if prevdup and/or postdup are in bestfree table.
 791                  */
 792                 dfp = xfs_dir2_data_freefind(hdr, bf, prevdup);
 793                 dfp2 = xfs_dir2_data_freefind(hdr, bf, postdup);
 794                 /*
 795                  * We need a rescan unless there are exactly 2 free entries
 796                  * namely our two.  Then we know what's happening, otherwise
 797                  * since the third bestfree is there, there might be more
 798                  * entries.
 799                  */
 800                 needscan = (bf[2].length != 0);
 801                 /*
 802                  * Fix up the new big freespace.
 803                  */
 804                 be16_add_cpu(&prevdup->length, len + be16_to_cpu(postdup->length));
 805                 *xfs_dir2_data_unused_tag_p(prevdup) =
 806                         cpu_to_be16((char *)prevdup - (char *)hdr);
 807                 xfs_dir2_data_log_unused(args, bp, prevdup);
 808                 if (!needscan) {
 809                         /*
 810                          * Has to be the case that entries 0 and 1 are
 811                          * dfp and dfp2 (don't know which is which), and
 812                          * entry 2 is empty.
 813                          * Remove entry 1 first then entry 0.
 814                          */
 815                         ASSERT(dfp && dfp2);
 816                         if (dfp == &bf[1]) {
 817                                 dfp = &bf[0];
 818                                 ASSERT(dfp2 == dfp);
 819                                 dfp2 = &bf[1];
 820                         }
 821                         xfs_dir2_data_freeremove(hdr, bf, dfp2, needlogp);
 822                         xfs_dir2_data_freeremove(hdr, bf, dfp, needlogp);
 823                         /*
 824                          * Now insert the new entry.
 825                          */
 826                         dfp = xfs_dir2_data_freeinsert(hdr, bf, prevdup,
 827                                                        needlogp);
 828                         ASSERT(dfp == &bf[0]);
 829                         ASSERT(dfp->length == prevdup->length);
 830                         ASSERT(!dfp[1].length);
 831                         ASSERT(!dfp[2].length);
 832                 }
 833         }
 834         /*
 835          * The entry before us is free, merge with it.
 836          */
 837         else if (prevdup) {
 838                 dfp = xfs_dir2_data_freefind(hdr, bf, prevdup);
 839                 be16_add_cpu(&prevdup->length, len);
 840                 *xfs_dir2_data_unused_tag_p(prevdup) =
 841                         cpu_to_be16((char *)prevdup - (char *)hdr);
 842                 xfs_dir2_data_log_unused(args, bp, prevdup);
 843                 /*
 844                  * If the previous entry was in the table, the new entry
 845                  * is longer, so it will be in the table too.  Remove
 846                  * the old one and add the new one.
 847                  */
 848                 if (dfp) {
 849                         xfs_dir2_data_freeremove(hdr, bf, dfp, needlogp);
 850                         xfs_dir2_data_freeinsert(hdr, bf, prevdup, needlogp);
 851                 }
 852                 /*
 853                  * Otherwise we need a scan if the new entry is big enough.
 854                  */
 855                 else {
 856                         needscan = be16_to_cpu(prevdup->length) >
 857                                    be16_to_cpu(bf[2].length);
 858                 }
 859         }
 860         /*
 861          * The following entry is free, merge with it.
 862          */
 863         else if (postdup) {
 864                 dfp = xfs_dir2_data_freefind(hdr, bf, postdup);
 865                 newdup = (xfs_dir2_data_unused_t *)((char *)hdr + offset);
 866                 newdup->freetag = cpu_to_be16(XFS_DIR2_DATA_FREE_TAG);
 867                 newdup->length = cpu_to_be16(len + be16_to_cpu(postdup->length));
 868                 *xfs_dir2_data_unused_tag_p(newdup) =
 869                         cpu_to_be16((char *)newdup - (char *)hdr);
 870                 xfs_dir2_data_log_unused(args, bp, newdup);
 871                 /*
 872                  * If the following entry was in the table, the new entry
 873                  * is longer, so it will be in the table too.  Remove
 874                  * the old one and add the new one.
 875                  */
 876                 if (dfp) {
 877                         xfs_dir2_data_freeremove(hdr, bf, dfp, needlogp);
 878                         xfs_dir2_data_freeinsert(hdr, bf, newdup, needlogp);
 879                 }
 880                 /*
 881                  * Otherwise we need a scan if the new entry is big enough.
 882                  */
 883                 else {
 884                         needscan = be16_to_cpu(newdup->length) >
 885                                    be16_to_cpu(bf[2].length);
 886                 }
 887         }
 888         /*
 889          * Neither neighbor is free.  Make a new entry.
 890          */
 891         else {
 892                 newdup = (xfs_dir2_data_unused_t *)((char *)hdr + offset);
 893                 newdup->freetag = cpu_to_be16(XFS_DIR2_DATA_FREE_TAG);
 894                 newdup->length = cpu_to_be16(len);
 895                 *xfs_dir2_data_unused_tag_p(newdup) =
 896                         cpu_to_be16((char *)newdup - (char *)hdr);
 897                 xfs_dir2_data_log_unused(args, bp, newdup);
 898                 xfs_dir2_data_freeinsert(hdr, bf, newdup, needlogp);
 899         }
 900         *needscanp = needscan;
 901 }
 902
 903 /*
 904  * Take a byte range out of an existing unused space and make it un-free.
 905  */
 906 void
 907 xfs_dir2_data_use_free(
 908         struct xfs_da_args      *args,
 909         struct xfs_buf          *bp,
 910         xfs_dir2_data_unused_t  *dup,           /* unused entry */
 911         xfs_dir2_data_aoff_t    offset,         /* starting offset to use */
 912         xfs_dir2_data_aoff_t    len,            /* length to use */
 913         int                     *needlogp,      /* out: need to log header */
 914         int                     *needscanp)     /* out: need regen bestfree */
 915 {
 916         xfs_dir2_data_hdr_t     *hdr;           /* data block header */
 917         xfs_dir2_data_free_t    *dfp;           /* bestfree pointer */
 918         int                     matchback;      /* matches end of freespace */
 919         int                     matchfront;     /* matches start of freespace */
 920         int                     needscan;       /* need to regen bestfree */
 921         xfs_dir2_data_unused_t  *newdup;        /* new unused entry */
 922         xfs_dir2_data_unused_t  *newdup2;       /* another new unused entry */
 923         int                     oldlen;         /* old unused entry's length */
 924         struct xfs_dir2_data_free *bf;
 925
 926         hdr = bp->b_addr;
 927         ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
 928                hdr->magic == cpu_to_be32(XFS_DIR3_DATA_MAGIC) ||
 929                hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
 930                hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC));
 931         ASSERT(be16_to_cpu(dup->freetag) == XFS_DIR2_DATA_FREE_TAG);
 932         ASSERT(offset >= (char *)dup - (char *)hdr);
 933         ASSERT(offset + len <= (char *)dup + be16_to_cpu(dup->length) - (char *)hdr);
 934         ASSERT((char *)dup - (char *)hdr == be16_to_cpu(*xfs_dir2_data_unused_tag_p(dup)));
 935         /*
 936          * Look up the entry in the bestfree table.
 937          */
 938         oldlen = be16_to_cpu(dup->length);
 939         bf = args->dp->d_ops->data_bestfree_p(hdr);
 940         dfp = xfs_dir2_data_freefind(hdr, bf, dup);
 941         ASSERT(dfp || oldlen <= be16_to_cpu(bf[2].length));
 942         /*
 943          * Check for alignment with front and back of the entry.
 944          */
 945         matchfront = (char *)dup - (char *)hdr == offset;
 946         matchback = (char *)dup + oldlen - (char *)hdr == offset + len;
 947         ASSERT(*needscanp == 0);
 948         needscan = 0;
 949         /*
 950          * If we matched it exactly we just need to get rid of it from
 951          * the bestfree table.
 952          */
 953         if (matchfront && matchback) {
 954                 if (dfp) {
 955                         needscan = (bf[2].offset != 0);
 956                         if (!needscan)
 957                                 xfs_dir2_data_freeremove(hdr, bf, dfp,
 958                                                          needlogp);
 959                 }
 960         }
 961         /*
 962          * We match the first part of the entry.
 963          * Make a new entry with the remaining freespace.
 964          */
 965         else if (matchfront) {
 966                 newdup = (xfs_dir2_data_unused_t *)((char *)hdr + offset + len);
 967                 newdup->freetag = cpu_to_be16(XFS_DIR2_DATA_FREE_TAG);
 968                 newdup->length = cpu_to_be16(oldlen - len);
 969                 *xfs_dir2_data_unused_tag_p(newdup) =
 970                         cpu_to_be16((char *)newdup - (char *)hdr);
 971                 xfs_dir2_data_log_unused(args, bp, newdup);
 972                 /*
 973                  * If it was in the table, remove it and add the new one.
 974                  */
 975                 if (dfp) {
 976                         xfs_dir2_data_freeremove(hdr, bf, dfp, needlogp);
 977                         dfp = xfs_dir2_data_freeinsert(hdr, bf, newdup,
 978                                                        needlogp);
 979                         ASSERT(dfp != NULL);
 980                         ASSERT(dfp->length == newdup->length);
 981                         ASSERT(be16_to_cpu(dfp->offset) == (char *)newdup - (char *)hdr);
 982                         /*
 983                          * If we got inserted at the last slot,
 984                          * that means we don't know if there was a better
 985                          * choice for the last slot, or not.  Rescan.
 986                          */
 987                         needscan = dfp == &bf[2];
 988                 }
 989         }
 990         /*
 991          * We match the last part of the entry.
 992          * Trim the allocated space off the tail of the entry.
 993          */
 994         else if (matchback) {
 995                 newdup = dup;
 996                 newdup->length = cpu_to_be16(((char *)hdr + offset) - (char *)newdup);
 997                 *xfs_dir2_data_unused_tag_p(newdup) =
 998                         cpu_to_be16((char *)newdup - (char *)hdr);
 999                 xfs_dir2_data_log_unused(args, bp, newdup);
1000                 /*
1001                  * If it was in the table, remove it and add the new one.
1002                  */
1003                 if (dfp) {
1004                         xfs_dir2_data_freeremove(hdr, bf, dfp, needlogp);
1005                         dfp = xfs_dir2_data_freeinsert(hdr, bf, newdup,
1006                                                        needlogp);
1007                         ASSERT(dfp != NULL);
1008                         ASSERT(dfp->length == newdup->length);
1009                         ASSERT(be16_to_cpu(dfp->offset) == (char *)newdup - (char *)hdr);
1010                         /*
1011                          * If we got inserted at the last slot,
1012                          * that means we don't know if there was a better
1013                          * choice for the last slot, or not.  Rescan.
1014                          */
1015                         needscan = dfp == &bf[2];
1016                 }
1017         }
1018         /*
1019          * Poking out the middle of an entry.
1020          * Make two new entries.
1021          */
1022         else {
1023                 newdup = dup;
1024                 newdup->length = cpu_to_be16(((char *)hdr + offset) - (char *)newdup);
1025                 *xfs_dir2_data_unused_tag_p(newdup) =
1026                         cpu_to_be16((char *)newdup - (char *)hdr);
1027                 xfs_dir2_data_log_unused(args, bp, newdup);
1028                 newdup2 = (xfs_dir2_data_unused_t *)((char *)hdr + offset + len);
1029                 newdup2->freetag = cpu_to_be16(XFS_DIR2_DATA_FREE_TAG);
1030                 newdup2->length = cpu_to_be16(oldlen - len - be16_to_cpu(newdup->length));
1031                 *xfs_dir2_data_unused_tag_p(newdup2) =
1032                         cpu_to_be16((char *)newdup2 - (char *)hdr);
1033                 xfs_dir2_data_log_unused(args, bp, newdup2);
1034                 /*
1035                  * If the old entry was in the table, we need to scan
1036                  * if the 3rd entry was valid, since these entries
1037                  * are smaller than the old one.
1038                  * If we don't need to scan that means there were 1 or 2
1039                  * entries in the table, and removing the old and adding
1040                  * the 2 new will work.
1041                  */
1042                 if (dfp) {
1043                         needscan = (bf[2].length != 0);
1044                         if (!needscan) {
1045                                 xfs_dir2_data_freeremove(hdr, bf, dfp,
1046                                                          needlogp);
1047                                 xfs_dir2_data_freeinsert(hdr, bf, newdup,
1048                                                          needlogp);
1049                                 xfs_dir2_data_freeinsert(hdr, bf, newdup2,
1050                                                          needlogp);
1051                         }
1052                 }
1053         }
1054         *needscanp = needscan;
1055 }