linux/fs/xfs/xfs_dir2_data.c
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   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_types.h"
  22#include "xfs_log.h"
  23#include "xfs_trans.h"
  24#include "xfs_sb.h"
  25#include "xfs_ag.h"
  26#include "xfs_mount.h"
  27#include "xfs_da_btree.h"
  28#include "xfs_bmap_btree.h"
  29#include "xfs_dinode.h"
  30#include "xfs_inode.h"
  31#include "xfs_dir2_format.h"
  32#include "xfs_dir2_priv.h"
  33#include "xfs_error.h"
  34#include "xfs_buf_item.h"
  35#include "xfs_cksum.h"
  36
  37STATIC xfs_dir2_data_free_t *
  38xfs_dir2_data_freefind(xfs_dir2_data_hdr_t *hdr, xfs_dir2_data_unused_t *dup);
  39
  40/*
  41 * Check the consistency of the data block.
  42 * The input can also be a block-format directory.
  43 * Return 0 is the buffer is good, otherwise an error.
  44 */
  45int
  46__xfs_dir3_data_check(
  47        struct xfs_inode        *dp,            /* incore inode pointer */
  48        struct xfs_buf          *bp)            /* data block's buffer */
  49{
  50        xfs_dir2_dataptr_t      addr;           /* addr for leaf lookup */
  51        xfs_dir2_data_free_t    *bf;            /* bestfree table */
  52        xfs_dir2_block_tail_t   *btp=NULL;      /* block tail */
  53        int                     count;          /* count of entries found */
  54        xfs_dir2_data_hdr_t     *hdr;           /* data block header */
  55        xfs_dir2_data_entry_t   *dep;           /* data entry */
  56        xfs_dir2_data_free_t    *dfp;           /* bestfree entry */
  57        xfs_dir2_data_unused_t  *dup;           /* unused entry */
  58        char                    *endp;          /* end of useful data */
  59        int                     freeseen;       /* mask of bestfrees seen */
  60        xfs_dahash_t            hash;           /* hash of current name */
  61        int                     i;              /* leaf index */
  62        int                     lastfree;       /* last entry was unused */
  63        xfs_dir2_leaf_entry_t   *lep=NULL;      /* block leaf entries */
  64        xfs_mount_t             *mp;            /* filesystem mount point */
  65        char                    *p;             /* current data position */
  66        int                     stale;          /* count of stale leaves */
  67        struct xfs_name         name;
  68
  69        mp = bp->b_target->bt_mount;
  70        hdr = bp->b_addr;
  71        bf = xfs_dir3_data_bestfree_p(hdr);
  72        p = (char *)xfs_dir3_data_entry_p(hdr);
  73
  74        switch (hdr->magic) {
  75        case cpu_to_be32(XFS_DIR3_BLOCK_MAGIC):
  76        case cpu_to_be32(XFS_DIR2_BLOCK_MAGIC):
  77                btp = xfs_dir2_block_tail_p(mp, hdr);
  78                lep = xfs_dir2_block_leaf_p(btp);
  79                endp = (char *)lep;
  80                break;
  81        case cpu_to_be32(XFS_DIR3_DATA_MAGIC):
  82        case cpu_to_be32(XFS_DIR2_DATA_MAGIC):
  83                endp = (char *)hdr + mp->m_dirblksize;
  84                break;
  85        default:
  86                XFS_ERROR_REPORT("Bad Magic", XFS_ERRLEVEL_LOW, mp);
  87                return EFSCORRUPTED;
  88        }
  89
  90        count = lastfree = freeseen = 0;
  91        /*
  92         * Account for zero bestfree entries.
  93         */
  94        if (!bf[0].length) {
  95                XFS_WANT_CORRUPTED_RETURN(!bf[0].offset);
  96                freeseen |= 1 << 0;
  97        }
  98        if (!bf[1].length) {
  99                XFS_WANT_CORRUPTED_RETURN(!bf[1].offset);
 100                freeseen |= 1 << 1;
 101        }
 102        if (!bf[2].length) {
 103                XFS_WANT_CORRUPTED_RETURN(!bf[2].offset);
 104                freeseen |= 1 << 2;
 105        }
 106
 107        XFS_WANT_CORRUPTED_RETURN(be16_to_cpu(bf[0].length) >=
 108                                                be16_to_cpu(bf[1].length));
 109        XFS_WANT_CORRUPTED_RETURN(be16_to_cpu(bf[1].length) >=
 110                                                be16_to_cpu(bf[2].length));
 111        /*
 112         * Loop over the data/unused entries.
 113         */
 114        while (p < endp) {
 115                dup = (xfs_dir2_data_unused_t *)p;
 116                /*
 117                 * If it's unused, look for the space in the bestfree table.
 118                 * If we find it, account for that, else make sure it
 119                 * doesn't need to be there.
 120                 */
 121                if (be16_to_cpu(dup->freetag) == XFS_DIR2_DATA_FREE_TAG) {
 122                        XFS_WANT_CORRUPTED_RETURN(lastfree == 0);
 123                        XFS_WANT_CORRUPTED_RETURN(
 124                                be16_to_cpu(*xfs_dir2_data_unused_tag_p(dup)) ==
 125                                               (char *)dup - (char *)hdr);
 126                        dfp = xfs_dir2_data_freefind(hdr, dup);
 127                        if (dfp) {
 128                                i = (int)(dfp - bf);
 129                                XFS_WANT_CORRUPTED_RETURN(
 130                                        (freeseen & (1 << i)) == 0);
 131                                freeseen |= 1 << i;
 132                        } else {
 133                                XFS_WANT_CORRUPTED_RETURN(
 134                                        be16_to_cpu(dup->length) <=
 135                                                be16_to_cpu(bf[2].length));
 136                        }
 137                        p += be16_to_cpu(dup->length);
 138                        lastfree = 1;
 139                        continue;
 140                }
 141                /*
 142                 * It's a real entry.  Validate the fields.
 143                 * If this is a block directory then make sure it's
 144                 * in the leaf section of the block.
 145                 * The linear search is crude but this is DEBUG code.
 146                 */
 147                dep = (xfs_dir2_data_entry_t *)p;
 148                XFS_WANT_CORRUPTED_RETURN(dep->namelen != 0);
 149                XFS_WANT_CORRUPTED_RETURN(
 150                        !xfs_dir_ino_validate(mp, be64_to_cpu(dep->inumber)));
 151                XFS_WANT_CORRUPTED_RETURN(
 152                        be16_to_cpu(*xfs_dir2_data_entry_tag_p(dep)) ==
 153                                               (char *)dep - (char *)hdr);
 154                count++;
 155                lastfree = 0;
 156                if (hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
 157                    hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC)) {
 158                        addr = xfs_dir2_db_off_to_dataptr(mp, mp->m_dirdatablk,
 159                                (xfs_dir2_data_aoff_t)
 160                                ((char *)dep - (char *)hdr));
 161                        name.name = dep->name;
 162                        name.len = dep->namelen;
 163                        hash = mp->m_dirnameops->hashname(&name);
 164                        for (i = 0; i < be32_to_cpu(btp->count); i++) {
 165                                if (be32_to_cpu(lep[i].address) == addr &&
 166                                    be32_to_cpu(lep[i].hashval) == hash)
 167                                        break;
 168                        }
 169                        XFS_WANT_CORRUPTED_RETURN(i < be32_to_cpu(btp->count));
 170                }
 171                p += xfs_dir2_data_entsize(dep->namelen);
 172        }
 173        /*
 174         * Need to have seen all the entries and all the bestfree slots.
 175         */
 176        XFS_WANT_CORRUPTED_RETURN(freeseen == 7);
 177        if (hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
 178            hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC)) {
 179                for (i = stale = 0; i < be32_to_cpu(btp->count); i++) {
 180                        if (lep[i].address ==
 181                            cpu_to_be32(XFS_DIR2_NULL_DATAPTR))
 182                                stale++;
 183                        if (i > 0)
 184                                XFS_WANT_CORRUPTED_RETURN(
 185                                        be32_to_cpu(lep[i].hashval) >=
 186                                                be32_to_cpu(lep[i - 1].hashval));
 187                }
 188                XFS_WANT_CORRUPTED_RETURN(count ==
 189                        be32_to_cpu(btp->count) - be32_to_cpu(btp->stale));
 190                XFS_WANT_CORRUPTED_RETURN(stale == be32_to_cpu(btp->stale));
 191        }
 192        return 0;
 193}
 194
 195static bool
 196xfs_dir3_data_verify(
 197        struct xfs_buf          *bp)
 198{
 199        struct xfs_mount        *mp = bp->b_target->bt_mount;
 200        struct xfs_dir3_blk_hdr *hdr3 = bp->b_addr;
 201
 202        if (xfs_sb_version_hascrc(&mp->m_sb)) {
 203                if (hdr3->magic != cpu_to_be32(XFS_DIR3_DATA_MAGIC))
 204                        return false;
 205                if (!uuid_equal(&hdr3->uuid, &mp->m_sb.sb_uuid))
 206                        return false;
 207                if (be64_to_cpu(hdr3->blkno) != bp->b_bn)
 208                        return false;
 209        } else {
 210                if (hdr3->magic != cpu_to_be32(XFS_DIR2_DATA_MAGIC))
 211                        return false;
 212        }
 213        if (__xfs_dir3_data_check(NULL, bp))
 214                return false;
 215        return true;
 216}
 217
 218/*
 219 * Readahead of the first block of the directory when it is opened is completely
 220 * oblivious to the format of the directory. Hence we can either get a block
 221 * format buffer or a data format buffer on readahead.
 222 */
 223static void
 224xfs_dir3_data_reada_verify(
 225        struct xfs_buf          *bp)
 226{
 227        struct xfs_mount        *mp = bp->b_target->bt_mount;
 228        struct xfs_dir2_data_hdr *hdr = bp->b_addr;
 229
 230        switch (hdr->magic) {
 231        case cpu_to_be32(XFS_DIR2_BLOCK_MAGIC):
 232        case cpu_to_be32(XFS_DIR3_BLOCK_MAGIC):
 233                bp->b_ops = &xfs_dir3_block_buf_ops;
 234                bp->b_ops->verify_read(bp);
 235                return;
 236        case cpu_to_be32(XFS_DIR2_DATA_MAGIC):
 237        case cpu_to_be32(XFS_DIR3_DATA_MAGIC):
 238                xfs_dir3_data_verify(bp);
 239                return;
 240        default:
 241                XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, hdr);
 242                xfs_buf_ioerror(bp, EFSCORRUPTED);
 243                break;
 244        }
 245}
 246
 247static void
 248xfs_dir3_data_read_verify(
 249        struct xfs_buf  *bp)
 250{
 251        struct xfs_mount        *mp = bp->b_target->bt_mount;
 252
 253        if ((xfs_sb_version_hascrc(&mp->m_sb) &&
 254             !xfs_verify_cksum(bp->b_addr, BBTOB(bp->b_length),
 255                                          XFS_DIR3_DATA_CRC_OFF)) ||
 256            !xfs_dir3_data_verify(bp)) {
 257                XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, bp->b_addr);
 258                xfs_buf_ioerror(bp, EFSCORRUPTED);
 259        }
 260}
 261
 262static void
 263xfs_dir3_data_write_verify(
 264        struct xfs_buf  *bp)
 265{
 266        struct xfs_mount        *mp = bp->b_target->bt_mount;
 267        struct xfs_buf_log_item *bip = bp->b_fspriv;
 268        struct xfs_dir3_blk_hdr *hdr3 = bp->b_addr;
 269
 270        if (!xfs_dir3_data_verify(bp)) {
 271                XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, bp->b_addr);
 272                xfs_buf_ioerror(bp, EFSCORRUPTED);
 273                return;
 274        }
 275
 276        if (!xfs_sb_version_hascrc(&mp->m_sb))
 277                return;
 278
 279        if (bip)
 280                hdr3->lsn = cpu_to_be64(bip->bli_item.li_lsn);
 281
 282        xfs_update_cksum(bp->b_addr, BBTOB(bp->b_length), XFS_DIR3_DATA_CRC_OFF);
 283}
 284
 285const struct xfs_buf_ops xfs_dir3_data_buf_ops = {
 286        .verify_read = xfs_dir3_data_read_verify,
 287        .verify_write = xfs_dir3_data_write_verify,
 288};
 289
 290static const struct xfs_buf_ops xfs_dir3_data_reada_buf_ops = {
 291        .verify_read = xfs_dir3_data_reada_verify,
 292        .verify_write = xfs_dir3_data_write_verify,
 293};
 294
 295
 296int
 297xfs_dir3_data_read(
 298        struct xfs_trans        *tp,
 299        struct xfs_inode        *dp,
 300        xfs_dablk_t             bno,
 301        xfs_daddr_t             mapped_bno,
 302        struct xfs_buf          **bpp)
 303{
 304        int                     err;
 305
 306        err = xfs_da_read_buf(tp, dp, bno, mapped_bno, bpp,
 307                                XFS_DATA_FORK, &xfs_dir3_data_buf_ops);
 308        if (!err && tp)
 309                xfs_trans_buf_set_type(tp, *bpp, XFS_BLFT_DIR_DATA_BUF);
 310        return err;
 311}
 312
 313int
 314xfs_dir3_data_readahead(
 315        struct xfs_trans        *tp,
 316        struct xfs_inode        *dp,
 317        xfs_dablk_t             bno,
 318        xfs_daddr_t             mapped_bno)
 319{
 320        return xfs_da_reada_buf(tp, dp, bno, mapped_bno,
 321                                XFS_DATA_FORK, &xfs_dir3_data_reada_buf_ops);
 322}
 323
 324/*
 325 * Given a data block and an unused entry from that block,
 326 * return the bestfree entry if any that corresponds to it.
 327 */
 328STATIC xfs_dir2_data_free_t *
 329xfs_dir2_data_freefind(
 330        xfs_dir2_data_hdr_t     *hdr,           /* data block */
 331        xfs_dir2_data_unused_t  *dup)           /* data unused entry */
 332{
 333        xfs_dir2_data_free_t    *dfp;           /* bestfree entry */
 334        xfs_dir2_data_aoff_t    off;            /* offset value needed */
 335        struct xfs_dir2_data_free *bf;
 336#if defined(DEBUG) && defined(__KERNEL__)
 337        int                     matched;        /* matched the value */
 338        int                     seenzero;       /* saw a 0 bestfree entry */
 339#endif
 340
 341        off = (xfs_dir2_data_aoff_t)((char *)dup - (char *)hdr);
 342        bf = xfs_dir3_data_bestfree_p(hdr);
 343
 344#if defined(DEBUG) && defined(__KERNEL__)
 345        /*
 346         * Validate some consistency in the bestfree table.
 347         * Check order, non-overlapping entries, and if we find the
 348         * one we're looking for it has to be exact.
 349         */
 350        ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
 351               hdr->magic == cpu_to_be32(XFS_DIR3_DATA_MAGIC) ||
 352               hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
 353               hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC));
 354        for (dfp = &bf[0], seenzero = matched = 0;
 355             dfp < &bf[XFS_DIR2_DATA_FD_COUNT];
 356             dfp++) {
 357                if (!dfp->offset) {
 358                        ASSERT(!dfp->length);
 359                        seenzero = 1;
 360                        continue;
 361                }
 362                ASSERT(seenzero == 0);
 363                if (be16_to_cpu(dfp->offset) == off) {
 364                        matched = 1;
 365                        ASSERT(dfp->length == dup->length);
 366                } else if (off < be16_to_cpu(dfp->offset))
 367                        ASSERT(off + be16_to_cpu(dup->length) <= be16_to_cpu(dfp->offset));
 368                else
 369                        ASSERT(be16_to_cpu(dfp->offset) + be16_to_cpu(dfp->length) <= off);
 370                ASSERT(matched || be16_to_cpu(dfp->length) >= be16_to_cpu(dup->length));
 371                if (dfp > &bf[0])
 372                        ASSERT(be16_to_cpu(dfp[-1].length) >= be16_to_cpu(dfp[0].length));
 373        }
 374#endif
 375        /*
 376         * If this is smaller than the smallest bestfree entry,
 377         * it can't be there since they're sorted.
 378         */
 379        if (be16_to_cpu(dup->length) <
 380            be16_to_cpu(bf[XFS_DIR2_DATA_FD_COUNT - 1].length))
 381                return NULL;
 382        /*
 383         * Look at the three bestfree entries for our guy.
 384         */
 385        for (dfp = &bf[0]; dfp < &bf[XFS_DIR2_DATA_FD_COUNT]; dfp++) {
 386                if (!dfp->offset)
 387                        return NULL;
 388                if (be16_to_cpu(dfp->offset) == off)
 389                        return dfp;
 390        }
 391        /*
 392         * Didn't find it.  This only happens if there are duplicate lengths.
 393         */
 394        return NULL;
 395}
 396
 397/*
 398 * Insert an unused-space entry into the bestfree table.
 399 */
 400xfs_dir2_data_free_t *                          /* entry inserted */
 401xfs_dir2_data_freeinsert(
 402        xfs_dir2_data_hdr_t     *hdr,           /* data block pointer */
 403        xfs_dir2_data_unused_t  *dup,           /* unused space */
 404        int                     *loghead)       /* log the data header (out) */
 405{
 406        xfs_dir2_data_free_t    *dfp;           /* bestfree table pointer */
 407        xfs_dir2_data_free_t    new;            /* new bestfree entry */
 408
 409        ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
 410               hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
 411               hdr->magic == cpu_to_be32(XFS_DIR3_DATA_MAGIC) ||
 412               hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC));
 413
 414        dfp = xfs_dir3_data_bestfree_p(hdr);
 415        new.length = dup->length;
 416        new.offset = cpu_to_be16((char *)dup - (char *)hdr);
 417
 418        /*
 419         * Insert at position 0, 1, or 2; or not at all.
 420         */
 421        if (be16_to_cpu(new.length) > be16_to_cpu(dfp[0].length)) {
 422                dfp[2] = dfp[1];
 423                dfp[1] = dfp[0];
 424                dfp[0] = new;
 425                *loghead = 1;
 426                return &dfp[0];
 427        }
 428        if (be16_to_cpu(new.length) > be16_to_cpu(dfp[1].length)) {
 429                dfp[2] = dfp[1];
 430                dfp[1] = new;
 431                *loghead = 1;
 432                return &dfp[1];
 433        }
 434        if (be16_to_cpu(new.length) > be16_to_cpu(dfp[2].length)) {
 435                dfp[2] = new;
 436                *loghead = 1;
 437                return &dfp[2];
 438        }
 439        return NULL;
 440}
 441
 442/*
 443 * Remove a bestfree entry from the table.
 444 */
 445STATIC void
 446xfs_dir2_data_freeremove(
 447        xfs_dir2_data_hdr_t     *hdr,           /* data block header */
 448        xfs_dir2_data_free_t    *dfp,           /* bestfree entry pointer */
 449        int                     *loghead)       /* out: log data header */
 450{
 451        struct xfs_dir2_data_free *bf;
 452
 453        ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
 454               hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
 455               hdr->magic == cpu_to_be32(XFS_DIR3_DATA_MAGIC) ||
 456               hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC));
 457
 458        /*
 459         * It's the first entry, slide the next 2 up.
 460         */
 461        bf = xfs_dir3_data_bestfree_p(hdr);
 462        if (dfp == &bf[0]) {
 463                bf[0] = bf[1];
 464                bf[1] = bf[2];
 465        }
 466        /*
 467         * It's the second entry, slide the 3rd entry up.
 468         */
 469        else if (dfp == &bf[1])
 470                bf[1] = bf[2];
 471        /*
 472         * Must be the last entry.
 473         */
 474        else
 475                ASSERT(dfp == &bf[2]);
 476        /*
 477         * Clear the 3rd entry, must be zero now.
 478         */
 479        bf[2].length = 0;
 480        bf[2].offset = 0;
 481        *loghead = 1;
 482}
 483
 484/*
 485 * Given a data block, reconstruct its bestfree map.
 486 */
 487void
 488xfs_dir2_data_freescan(
 489        xfs_mount_t             *mp,            /* filesystem mount point */
 490        xfs_dir2_data_hdr_t     *hdr,           /* data block header */
 491        int                     *loghead)       /* out: log data header */
 492{
 493        xfs_dir2_block_tail_t   *btp;           /* block tail */
 494        xfs_dir2_data_entry_t   *dep;           /* active data entry */
 495        xfs_dir2_data_unused_t  *dup;           /* unused data entry */
 496        struct xfs_dir2_data_free *bf;
 497        char                    *endp;          /* end of block's data */
 498        char                    *p;             /* current entry pointer */
 499
 500        ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
 501               hdr->magic == cpu_to_be32(XFS_DIR3_DATA_MAGIC) ||
 502               hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
 503               hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC));
 504
 505        /*
 506         * Start by clearing the table.
 507         */
 508        bf = xfs_dir3_data_bestfree_p(hdr);
 509        memset(bf, 0, sizeof(*bf) * XFS_DIR2_DATA_FD_COUNT);
 510        *loghead = 1;
 511        /*
 512         * Set up pointers.
 513         */
 514        p = (char *)xfs_dir3_data_entry_p(hdr);
 515        if (hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
 516            hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC)) {
 517                btp = xfs_dir2_block_tail_p(mp, hdr);
 518                endp = (char *)xfs_dir2_block_leaf_p(btp);
 519        } else
 520                endp = (char *)hdr + mp->m_dirblksize;
 521        /*
 522         * Loop over the block's entries.
 523         */
 524        while (p < endp) {
 525                dup = (xfs_dir2_data_unused_t *)p;
 526                /*
 527                 * If it's a free entry, insert it.
 528                 */
 529                if (be16_to_cpu(dup->freetag) == XFS_DIR2_DATA_FREE_TAG) {
 530                        ASSERT((char *)dup - (char *)hdr ==
 531                               be16_to_cpu(*xfs_dir2_data_unused_tag_p(dup)));
 532                        xfs_dir2_data_freeinsert(hdr, dup, loghead);
 533                        p += be16_to_cpu(dup->length);
 534                }
 535                /*
 536                 * For active entries, check their tags and skip them.
 537                 */
 538                else {
 539                        dep = (xfs_dir2_data_entry_t *)p;
 540                        ASSERT((char *)dep - (char *)hdr ==
 541                               be16_to_cpu(*xfs_dir2_data_entry_tag_p(dep)));
 542                        p += xfs_dir2_data_entsize(dep->namelen);
 543                }
 544        }
 545}
 546
 547/*
 548 * Initialize a data block at the given block number in the directory.
 549 * Give back the buffer for the created block.
 550 */
 551int                                             /* error */
 552xfs_dir3_data_init(
 553        xfs_da_args_t           *args,          /* directory operation args */
 554        xfs_dir2_db_t           blkno,          /* logical dir block number */
 555        struct xfs_buf          **bpp)          /* output block buffer */
 556{
 557        struct xfs_buf          *bp;            /* block buffer */
 558        xfs_dir2_data_hdr_t     *hdr;           /* data block header */
 559        xfs_inode_t             *dp;            /* incore directory inode */
 560        xfs_dir2_data_unused_t  *dup;           /* unused entry pointer */
 561        struct xfs_dir2_data_free *bf;
 562        int                     error;          /* error return value */
 563        int                     i;              /* bestfree index */
 564        xfs_mount_t             *mp;            /* filesystem mount point */
 565        xfs_trans_t             *tp;            /* transaction pointer */
 566        int                     t;              /* temp */
 567
 568        dp = args->dp;
 569        mp = dp->i_mount;
 570        tp = args->trans;
 571        /*
 572         * Get the buffer set up for the block.
 573         */
 574        error = xfs_da_get_buf(tp, dp, xfs_dir2_db_to_da(mp, blkno), -1, &bp,
 575                XFS_DATA_FORK);
 576        if (error)
 577                return error;
 578        bp->b_ops = &xfs_dir3_data_buf_ops;
 579        xfs_trans_buf_set_type(tp, bp, XFS_BLFT_DIR_DATA_BUF);
 580
 581        /*
 582         * Initialize the header.
 583         */
 584        hdr = bp->b_addr;
 585        if (xfs_sb_version_hascrc(&mp->m_sb)) {
 586                struct xfs_dir3_blk_hdr *hdr3 = bp->b_addr;
 587
 588                memset(hdr3, 0, sizeof(*hdr3));
 589                hdr3->magic = cpu_to_be32(XFS_DIR3_DATA_MAGIC);
 590                hdr3->blkno = cpu_to_be64(bp->b_bn);
 591                hdr3->owner = cpu_to_be64(dp->i_ino);
 592                uuid_copy(&hdr3->uuid, &mp->m_sb.sb_uuid);
 593
 594        } else
 595                hdr->magic = cpu_to_be32(XFS_DIR2_DATA_MAGIC);
 596
 597        bf = xfs_dir3_data_bestfree_p(hdr);
 598        bf[0].offset = cpu_to_be16(xfs_dir3_data_entry_offset(hdr));
 599        for (i = 1; i < XFS_DIR2_DATA_FD_COUNT; i++) {
 600                bf[i].length = 0;
 601                bf[i].offset = 0;
 602        }
 603
 604        /*
 605         * Set up an unused entry for the block's body.
 606         */
 607        dup = xfs_dir3_data_unused_p(hdr);
 608        dup->freetag = cpu_to_be16(XFS_DIR2_DATA_FREE_TAG);
 609
 610        t = mp->m_dirblksize - (uint)xfs_dir3_data_entry_offset(hdr);
 611        bf[0].length = cpu_to_be16(t);
 612        dup->length = cpu_to_be16(t);
 613        *xfs_dir2_data_unused_tag_p(dup) = cpu_to_be16((char *)dup - (char *)hdr);
 614        /*
 615         * Log it and return it.
 616         */
 617        xfs_dir2_data_log_header(tp, bp);
 618        xfs_dir2_data_log_unused(tp, bp, dup);
 619        *bpp = bp;
 620        return 0;
 621}
 622
 623/*
 624 * Log an active data entry from the block.
 625 */
 626void
 627xfs_dir2_data_log_entry(
 628        struct xfs_trans        *tp,
 629        struct xfs_buf          *bp,
 630        xfs_dir2_data_entry_t   *dep)           /* data entry pointer */
 631{
 632        xfs_dir2_data_hdr_t     *hdr = bp->b_addr;
 633
 634        ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
 635               hdr->magic == cpu_to_be32(XFS_DIR3_DATA_MAGIC) ||
 636               hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
 637               hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC));
 638
 639        xfs_trans_log_buf(tp, bp, (uint)((char *)dep - (char *)hdr),
 640                (uint)((char *)(xfs_dir2_data_entry_tag_p(dep) + 1) -
 641                       (char *)hdr - 1));
 642}
 643
 644/*
 645 * Log a data block header.
 646 */
 647void
 648xfs_dir2_data_log_header(
 649        struct xfs_trans        *tp,
 650        struct xfs_buf          *bp)
 651{
 652        xfs_dir2_data_hdr_t     *hdr = bp->b_addr;
 653
 654        ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
 655               hdr->magic == cpu_to_be32(XFS_DIR3_DATA_MAGIC) ||
 656               hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
 657               hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC));
 658
 659        xfs_trans_log_buf(tp, bp, 0, xfs_dir3_data_entry_offset(hdr) - 1);
 660}
 661
 662/*
 663 * Log a data unused entry.
 664 */
 665void
 666xfs_dir2_data_log_unused(
 667        struct xfs_trans        *tp,
 668        struct xfs_buf          *bp,
 669        xfs_dir2_data_unused_t  *dup)           /* data unused pointer */
 670{
 671        xfs_dir2_data_hdr_t     *hdr = bp->b_addr;
 672
 673        ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
 674               hdr->magic == cpu_to_be32(XFS_DIR3_DATA_MAGIC) ||
 675               hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
 676               hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC));
 677
 678        /*
 679         * Log the first part of the unused entry.
 680         */
 681        xfs_trans_log_buf(tp, bp, (uint)((char *)dup - (char *)hdr),
 682                (uint)((char *)&dup->length + sizeof(dup->length) -
 683                       1 - (char *)hdr));
 684        /*
 685         * Log the end (tag) of the unused entry.
 686         */
 687        xfs_trans_log_buf(tp, bp,
 688                (uint)((char *)xfs_dir2_data_unused_tag_p(dup) - (char *)hdr),
 689                (uint)((char *)xfs_dir2_data_unused_tag_p(dup) - (char *)hdr +
 690                       sizeof(xfs_dir2_data_off_t) - 1));
 691}
 692
 693/*
 694 * Make a byte range in the data block unused.
 695 * Its current contents are unimportant.
 696 */
 697void
 698xfs_dir2_data_make_free(
 699        struct xfs_trans        *tp,
 700        struct xfs_buf          *bp,
 701        xfs_dir2_data_aoff_t    offset,         /* starting byte offset */
 702        xfs_dir2_data_aoff_t    len,            /* length in bytes */
 703        int                     *needlogp,      /* out: log header */
 704        int                     *needscanp)     /* out: regen bestfree */
 705{
 706        xfs_dir2_data_hdr_t     *hdr;           /* data block pointer */
 707        xfs_dir2_data_free_t    *dfp;           /* bestfree pointer */
 708        char                    *endptr;        /* end of data area */
 709        xfs_mount_t             *mp;            /* filesystem mount point */
 710        int                     needscan;       /* need to regen bestfree */
 711        xfs_dir2_data_unused_t  *newdup;        /* new unused entry */
 712        xfs_dir2_data_unused_t  *postdup;       /* unused entry after us */
 713        xfs_dir2_data_unused_t  *prevdup;       /* unused entry before us */
 714        struct xfs_dir2_data_free *bf;
 715
 716        mp = tp->t_mountp;
 717        hdr = bp->b_addr;
 718
 719        /*
 720         * Figure out where the end of the data area is.
 721         */
 722        if (hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
 723            hdr->magic == cpu_to_be32(XFS_DIR3_DATA_MAGIC))
 724                endptr = (char *)hdr + mp->m_dirblksize;
 725        else {
 726                xfs_dir2_block_tail_t   *btp;   /* block tail */
 727
 728                ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
 729                        hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC));
 730                btp = xfs_dir2_block_tail_p(mp, hdr);
 731                endptr = (char *)xfs_dir2_block_leaf_p(btp);
 732        }
 733        /*
 734         * If this isn't the start of the block, then back up to
 735         * the previous entry and see if it's free.
 736         */
 737        if (offset > xfs_dir3_data_entry_offset(hdr)) {
 738                __be16                  *tagp;  /* tag just before us */
 739
 740                tagp = (__be16 *)((char *)hdr + offset) - 1;
 741                prevdup = (xfs_dir2_data_unused_t *)((char *)hdr + be16_to_cpu(*tagp));
 742                if (be16_to_cpu(prevdup->freetag) != XFS_DIR2_DATA_FREE_TAG)
 743                        prevdup = NULL;
 744        } else
 745                prevdup = NULL;
 746        /*
 747         * If this isn't the end of the block, see if the entry after
 748         * us is free.
 749         */
 750        if ((char *)hdr + offset + len < endptr) {
 751                postdup =
 752                        (xfs_dir2_data_unused_t *)((char *)hdr + offset + len);
 753                if (be16_to_cpu(postdup->freetag) != XFS_DIR2_DATA_FREE_TAG)
 754                        postdup = NULL;
 755        } else
 756                postdup = NULL;
 757        ASSERT(*needscanp == 0);
 758        needscan = 0;
 759        /*
 760         * Previous and following entries are both free,
 761         * merge everything into a single free entry.
 762         */
 763        bf = xfs_dir3_data_bestfree_p(hdr);
 764        if (prevdup && postdup) {
 765                xfs_dir2_data_free_t    *dfp2;  /* another bestfree pointer */
 766
 767                /*
 768                 * See if prevdup and/or postdup are in bestfree table.
 769                 */
 770                dfp = xfs_dir2_data_freefind(hdr, prevdup);
 771                dfp2 = xfs_dir2_data_freefind(hdr, postdup);
 772                /*
 773                 * We need a rescan unless there are exactly 2 free entries
 774                 * namely our two.  Then we know what's happening, otherwise
 775                 * since the third bestfree is there, there might be more
 776                 * entries.
 777                 */
 778                needscan = (bf[2].length != 0);
 779                /*
 780                 * Fix up the new big freespace.
 781                 */
 782                be16_add_cpu(&prevdup->length, len + be16_to_cpu(postdup->length));
 783                *xfs_dir2_data_unused_tag_p(prevdup) =
 784                        cpu_to_be16((char *)prevdup - (char *)hdr);
 785                xfs_dir2_data_log_unused(tp, bp, prevdup);
 786                if (!needscan) {
 787                        /*
 788                         * Has to be the case that entries 0 and 1 are
 789                         * dfp and dfp2 (don't know which is which), and
 790                         * entry 2 is empty.
 791                         * Remove entry 1 first then entry 0.
 792                         */
 793                        ASSERT(dfp && dfp2);
 794                        if (dfp == &bf[1]) {
 795                                dfp = &bf[0];
 796                                ASSERT(dfp2 == dfp);
 797                                dfp2 = &bf[1];
 798                        }
 799                        xfs_dir2_data_freeremove(hdr, dfp2, needlogp);
 800                        xfs_dir2_data_freeremove(hdr, dfp, needlogp);
 801                        /*
 802                         * Now insert the new entry.
 803                         */
 804                        dfp = xfs_dir2_data_freeinsert(hdr, prevdup, needlogp);
 805                        ASSERT(dfp == &bf[0]);
 806                        ASSERT(dfp->length == prevdup->length);
 807                        ASSERT(!dfp[1].length);
 808                        ASSERT(!dfp[2].length);
 809                }
 810        }
 811        /*
 812         * The entry before us is free, merge with it.
 813         */
 814        else if (prevdup) {
 815                dfp = xfs_dir2_data_freefind(hdr, prevdup);
 816                be16_add_cpu(&prevdup->length, len);
 817                *xfs_dir2_data_unused_tag_p(prevdup) =
 818                        cpu_to_be16((char *)prevdup - (char *)hdr);
 819                xfs_dir2_data_log_unused(tp, bp, prevdup);
 820                /*
 821                 * If the previous entry was in the table, the new entry
 822                 * is longer, so it will be in the table too.  Remove
 823                 * the old one and add the new one.
 824                 */
 825                if (dfp) {
 826                        xfs_dir2_data_freeremove(hdr, dfp, needlogp);
 827                        xfs_dir2_data_freeinsert(hdr, prevdup, needlogp);
 828                }
 829                /*
 830                 * Otherwise we need a scan if the new entry is big enough.
 831                 */
 832                else {
 833                        needscan = be16_to_cpu(prevdup->length) >
 834                                   be16_to_cpu(bf[2].length);
 835                }
 836        }
 837        /*
 838         * The following entry is free, merge with it.
 839         */
 840        else if (postdup) {
 841                dfp = xfs_dir2_data_freefind(hdr, postdup);
 842                newdup = (xfs_dir2_data_unused_t *)((char *)hdr + offset);
 843                newdup->freetag = cpu_to_be16(XFS_DIR2_DATA_FREE_TAG);
 844                newdup->length = cpu_to_be16(len + be16_to_cpu(postdup->length));
 845                *xfs_dir2_data_unused_tag_p(newdup) =
 846                        cpu_to_be16((char *)newdup - (char *)hdr);
 847                xfs_dir2_data_log_unused(tp, bp, newdup);
 848                /*
 849                 * If the following entry was in the table, the new entry
 850                 * is longer, so it will be in the table too.  Remove
 851                 * the old one and add the new one.
 852                 */
 853                if (dfp) {
 854                        xfs_dir2_data_freeremove(hdr, dfp, needlogp);
 855                        xfs_dir2_data_freeinsert(hdr, newdup, needlogp);
 856                }
 857                /*
 858                 * Otherwise we need a scan if the new entry is big enough.
 859                 */
 860                else {
 861                        needscan = be16_to_cpu(newdup->length) >
 862                                   be16_to_cpu(bf[2].length);
 863                }
 864        }
 865        /*
 866         * Neither neighbor is free.  Make a new entry.
 867         */
 868        else {
 869                newdup = (xfs_dir2_data_unused_t *)((char *)hdr + offset);
 870                newdup->freetag = cpu_to_be16(XFS_DIR2_DATA_FREE_TAG);
 871                newdup->length = cpu_to_be16(len);
 872                *xfs_dir2_data_unused_tag_p(newdup) =
 873                        cpu_to_be16((char *)newdup - (char *)hdr);
 874                xfs_dir2_data_log_unused(tp, bp, newdup);
 875                xfs_dir2_data_freeinsert(hdr, newdup, needlogp);
 876        }
 877        *needscanp = needscan;
 878}
 879
 880/*
 881 * Take a byte range out of an existing unused space and make it un-free.
 882 */
 883void
 884xfs_dir2_data_use_free(
 885        struct xfs_trans        *tp,
 886        struct xfs_buf          *bp,
 887        xfs_dir2_data_unused_t  *dup,           /* unused entry */
 888        xfs_dir2_data_aoff_t    offset,         /* starting offset to use */
 889        xfs_dir2_data_aoff_t    len,            /* length to use */
 890        int                     *needlogp,      /* out: need to log header */
 891        int                     *needscanp)     /* out: need regen bestfree */
 892{
 893        xfs_dir2_data_hdr_t     *hdr;           /* data block header */
 894        xfs_dir2_data_free_t    *dfp;           /* bestfree pointer */
 895        int                     matchback;      /* matches end of freespace */
 896        int                     matchfront;     /* matches start of freespace */
 897        int                     needscan;       /* need to regen bestfree */
 898        xfs_dir2_data_unused_t  *newdup;        /* new unused entry */
 899        xfs_dir2_data_unused_t  *newdup2;       /* another new unused entry */
 900        int                     oldlen;         /* old unused entry's length */
 901        struct xfs_dir2_data_free *bf;
 902
 903        hdr = bp->b_addr;
 904        ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
 905               hdr->magic == cpu_to_be32(XFS_DIR3_DATA_MAGIC) ||
 906               hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
 907               hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC));
 908        ASSERT(be16_to_cpu(dup->freetag) == XFS_DIR2_DATA_FREE_TAG);
 909        ASSERT(offset >= (char *)dup - (char *)hdr);
 910        ASSERT(offset + len <= (char *)dup + be16_to_cpu(dup->length) - (char *)hdr);
 911        ASSERT((char *)dup - (char *)hdr == be16_to_cpu(*xfs_dir2_data_unused_tag_p(dup)));
 912        /*
 913         * Look up the entry in the bestfree table.
 914         */
 915        dfp = xfs_dir2_data_freefind(hdr, dup);
 916        oldlen = be16_to_cpu(dup->length);
 917        bf = xfs_dir3_data_bestfree_p(hdr);
 918        ASSERT(dfp || oldlen <= be16_to_cpu(bf[2].length));
 919        /*
 920         * Check for alignment with front and back of the entry.
 921         */
 922        matchfront = (char *)dup - (char *)hdr == offset;
 923        matchback = (char *)dup + oldlen - (char *)hdr == offset + len;
 924        ASSERT(*needscanp == 0);
 925        needscan = 0;
 926        /*
 927         * If we matched it exactly we just need to get rid of it from
 928         * the bestfree table.
 929         */
 930        if (matchfront && matchback) {
 931                if (dfp) {
 932                        needscan = (bf[2].offset != 0);
 933                        if (!needscan)
 934                                xfs_dir2_data_freeremove(hdr, dfp, needlogp);
 935                }
 936        }
 937        /*
 938         * We match the first part of the entry.
 939         * Make a new entry with the remaining freespace.
 940         */
 941        else if (matchfront) {
 942                newdup = (xfs_dir2_data_unused_t *)((char *)hdr + offset + len);
 943                newdup->freetag = cpu_to_be16(XFS_DIR2_DATA_FREE_TAG);
 944                newdup->length = cpu_to_be16(oldlen - len);
 945                *xfs_dir2_data_unused_tag_p(newdup) =
 946                        cpu_to_be16((char *)newdup - (char *)hdr);
 947                xfs_dir2_data_log_unused(tp, bp, newdup);
 948                /*
 949                 * If it was in the table, remove it and add the new one.
 950                 */
 951                if (dfp) {
 952                        xfs_dir2_data_freeremove(hdr, dfp, needlogp);
 953                        dfp = xfs_dir2_data_freeinsert(hdr, newdup, needlogp);
 954                        ASSERT(dfp != NULL);
 955                        ASSERT(dfp->length == newdup->length);
 956                        ASSERT(be16_to_cpu(dfp->offset) == (char *)newdup - (char *)hdr);
 957                        /*
 958                         * If we got inserted at the last slot,
 959                         * that means we don't know if there was a better
 960                         * choice for the last slot, or not.  Rescan.
 961                         */
 962                        needscan = dfp == &bf[2];
 963                }
 964        }
 965        /*
 966         * We match the last part of the entry.
 967         * Trim the allocated space off the tail of the entry.
 968         */
 969        else if (matchback) {
 970                newdup = dup;
 971                newdup->length = cpu_to_be16(((char *)hdr + offset) - (char *)newdup);
 972                *xfs_dir2_data_unused_tag_p(newdup) =
 973                        cpu_to_be16((char *)newdup - (char *)hdr);
 974                xfs_dir2_data_log_unused(tp, bp, newdup);
 975                /*
 976                 * If it was in the table, remove it and add the new one.
 977                 */
 978                if (dfp) {
 979                        xfs_dir2_data_freeremove(hdr, dfp, needlogp);
 980                        dfp = xfs_dir2_data_freeinsert(hdr, newdup, needlogp);
 981                        ASSERT(dfp != NULL);
 982                        ASSERT(dfp->length == newdup->length);
 983                        ASSERT(be16_to_cpu(dfp->offset) == (char *)newdup - (char *)hdr);
 984                        /*
 985                         * If we got inserted at the last slot,
 986                         * that means we don't know if there was a better
 987                         * choice for the last slot, or not.  Rescan.
 988                         */
 989                        needscan = dfp == &bf[2];
 990                }
 991        }
 992        /*
 993         * Poking out the middle of an entry.
 994         * Make two new entries.
 995         */
 996        else {
 997                newdup = dup;
 998                newdup->length = cpu_to_be16(((char *)hdr + offset) - (char *)newdup);
 999                *xfs_dir2_data_unused_tag_p(newdup) =
1000                        cpu_to_be16((char *)newdup - (char *)hdr);
1001                xfs_dir2_data_log_unused(tp, bp, newdup);
1002                newdup2 = (xfs_dir2_data_unused_t *)((char *)hdr + offset + len);
1003                newdup2->freetag = cpu_to_be16(XFS_DIR2_DATA_FREE_TAG);
1004                newdup2->length = cpu_to_be16(oldlen - len - be16_to_cpu(newdup->length));
1005                *xfs_dir2_data_unused_tag_p(newdup2) =
1006                        cpu_to_be16((char *)newdup2 - (char *)hdr);
1007                xfs_dir2_data_log_unused(tp, bp, newdup2);
1008                /*
1009                 * If the old entry was in the table, we need to scan
1010                 * if the 3rd entry was valid, since these entries
1011                 * are smaller than the old one.
1012                 * If we don't need to scan that means there were 1 or 2
1013                 * entries in the table, and removing the old and adding
1014                 * the 2 new will work.
1015                 */
1016                if (dfp) {
1017                        needscan = (bf[2].length != 0);
1018                        if (!needscan) {
1019                                xfs_dir2_data_freeremove(hdr, dfp, needlogp);
1020                                xfs_dir2_data_freeinsert(hdr, newdup, needlogp);
1021                                xfs_dir2_data_freeinsert(hdr, newdup2,
1022                                                         needlogp);
1023                        }
1024                }
1025        }
1026        *needscanp = needscan;
1027}
1028
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