fs/xfs/xfs_dir2_data.c

   1 /*
   2  * Copyright (c) 2000-2002,2005 Silicon Graphics, Inc.
   3  * All Rights Reserved.
   4  *
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU General Public License as
   7  * published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it would be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write the Free Software Foundation,
  16  * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  17  */
  18 #include "xfs.h"
  19 #include "xfs_fs.h"
  20 #include "xfs_types.h"
  21 #include "xfs_log.h"
  22 #include "xfs_trans.h"
  23 #include "xfs_sb.h"
  24 #include "xfs_ag.h"
  25 #include "xfs_mount.h"
  26 #include "xfs_da_btree.h"
  27 #include "xfs_bmap_btree.h"
  28 #include "xfs_dinode.h"
  29 #include "xfs_inode.h"
  30 #include "xfs_dir2_format.h"
  31 #include "xfs_dir2_priv.h"
  32 #include "xfs_error.h"
  33
  34 STATIC xfs_dir2_data_free_t *
  35 xfs_dir2_data_freefind(xfs_dir2_data_hdr_t *hdr, xfs_dir2_data_unused_t *dup);
  36
  37 /*
  38  * Check the consistency of the data block.
  39  * The input can also be a block-format directory.
  40  * Return 0 is the buffer is good, otherwise an error.
  41  */
  42 int
  43 __xfs_dir2_data_check(
  44         struct xfs_inode        *dp,            /* incore inode pointer */
  45         struct xfs_buf          *bp)            /* data block's buffer */
  46 {
  47         xfs_dir2_dataptr_t      addr;           /* addr for leaf lookup */
  48         xfs_dir2_data_free_t    *bf;            /* bestfree table */
  49         xfs_dir2_block_tail_t   *btp=NULL;      /* block tail */
  50         int                     count;          /* count of entries found */
  51         xfs_dir2_data_hdr_t     *hdr;           /* data block header */
  52         xfs_dir2_data_entry_t   *dep;           /* data entry */
  53         xfs_dir2_data_free_t    *dfp;           /* bestfree entry */
  54         xfs_dir2_data_unused_t  *dup;           /* unused entry */
  55         char                    *endp;          /* end of useful data */
  56         int                     freeseen;       /* mask of bestfrees seen */
  57         xfs_dahash_t            hash;           /* hash of current name */
  58         int                     i;              /* leaf index */
  59         int                     lastfree;       /* last entry was unused */
  60         xfs_dir2_leaf_entry_t   *lep=NULL;      /* block leaf entries */
  61         xfs_mount_t             *mp;            /* filesystem mount point */
  62         char                    *p;             /* current data position */
  63         int                     stale;          /* count of stale leaves */
  64         struct xfs_name         name;
  65
  66         mp = bp->b_target->bt_mount;
  67         hdr = bp->b_addr;
  68         bf = hdr->bestfree;
  69         p = (char *)(hdr + 1);
  70
  71         switch (hdr->magic) {
  72         case cpu_to_be32(XFS_DIR2_BLOCK_MAGIC):
  73                 btp = xfs_dir2_block_tail_p(mp, hdr);
  74                 lep = xfs_dir2_block_leaf_p(btp);
  75                 endp = (char *)lep;
  76                 break;
  77         case cpu_to_be32(XFS_DIR2_DATA_MAGIC):
  78                 endp = (char *)hdr + mp->m_dirblksize;
  79                 break;
  80         default:
  81                 XFS_ERROR_REPORT("Bad Magic", XFS_ERRLEVEL_LOW, mp);
  82                 return EFSCORRUPTED;
  83         }
  84
  85         count = lastfree = freeseen = 0;
  86         /*
  87          * Account for zero bestfree entries.
  88          */
  89         if (!bf[0].length) {
  90                 XFS_WANT_CORRUPTED_RETURN(!bf[0].offset);
  91                 freeseen |= 1 << 0;
  92         }
  93         if (!bf[1].length) {
  94                 XFS_WANT_CORRUPTED_RETURN(!bf[1].offset);
  95                 freeseen |= 1 << 1;
  96         }
  97         if (!bf[2].length) {
  98                 XFS_WANT_CORRUPTED_RETURN(!bf[2].offset);
  99                 freeseen |= 1 << 2;
 100         }
 101
 102         XFS_WANT_CORRUPTED_RETURN(be16_to_cpu(bf[0].length) >=
 103                                                 be16_to_cpu(bf[1].length));
 104         XFS_WANT_CORRUPTED_RETURN(be16_to_cpu(bf[1].length) >=
 105                                                 be16_to_cpu(bf[2].length));
 106         /*
 107          * Loop over the data/unused entries.
 108          */
 109         while (p < endp) {
 110                 dup = (xfs_dir2_data_unused_t *)p;
 111                 /*
 112                  * If it's unused, look for the space in the bestfree table.
 113                  * If we find it, account for that, else make sure it
 114                  * doesn't need to be there.
 115                  */
 116                 if (be16_to_cpu(dup->freetag) == XFS_DIR2_DATA_FREE_TAG) {
 117                         XFS_WANT_CORRUPTED_RETURN(lastfree == 0);
 118                         XFS_WANT_CORRUPTED_RETURN(
 119                                 be16_to_cpu(*xfs_dir2_data_unused_tag_p(dup)) ==
 120                                                (char *)dup - (char *)hdr);
 121                         dfp = xfs_dir2_data_freefind(hdr, dup);
 122                         if (dfp) {
 123                                 i = (int)(dfp - bf);
 124                                 XFS_WANT_CORRUPTED_RETURN(
 125                                         (freeseen & (1 << i)) == 0);
 126                                 freeseen |= 1 << i;
 127                         } else {
 128                                 XFS_WANT_CORRUPTED_RETURN(
 129                                         be16_to_cpu(dup->length) <=
 130                                                 be16_to_cpu(bf[2].length));
 131                         }
 132                         p += be16_to_cpu(dup->length);
 133                         lastfree = 1;
 134                         continue;
 135                 }
 136                 /*
 137                  * It's a real entry.  Validate the fields.
 138                  * If this is a block directory then make sure it's
 139                  * in the leaf section of the block.
 140                  * The linear search is crude but this is DEBUG code.
 141                  */
 142                 dep = (xfs_dir2_data_entry_t *)p;
 143                 XFS_WANT_CORRUPTED_RETURN(dep->namelen != 0);
 144                 XFS_WANT_CORRUPTED_RETURN(
 145                         !xfs_dir_ino_validate(mp, be64_to_cpu(dep->inumber)));
 146                 XFS_WANT_CORRUPTED_RETURN(
 147                         be16_to_cpu(*xfs_dir2_data_entry_tag_p(dep)) ==
 148                                                (char *)dep - (char *)hdr);
 149                 count++;
 150                 lastfree = 0;
 151                 if (hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC)) {
 152                         addr = xfs_dir2_db_off_to_dataptr(mp, mp->m_dirdatablk,
 153                                 (xfs_dir2_data_aoff_t)
 154                                 ((char *)dep - (char *)hdr));
 155                         name.name = dep->name;
 156                         name.len = dep->namelen;
 157                         hash = mp->m_dirnameops->hashname(&name);
 158                         for (i = 0; i < be32_to_cpu(btp->count); i++) {
 159                                 if (be32_to_cpu(lep[i].address) == addr &&
 160                                     be32_to_cpu(lep[i].hashval) == hash)
 161                                         break;
 162                         }
 163                         XFS_WANT_CORRUPTED_RETURN(i < be32_to_cpu(btp->count));
 164                 }
 165                 p += xfs_dir2_data_entsize(dep->namelen);
 166         }
 167         /*
 168          * Need to have seen all the entries and all the bestfree slots.
 169          */
 170         XFS_WANT_CORRUPTED_RETURN(freeseen == 7);
 171         if (hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC)) {
 172                 for (i = stale = 0; i < be32_to_cpu(btp->count); i++) {
 173                         if (lep[i].address ==
 174                             cpu_to_be32(XFS_DIR2_NULL_DATAPTR))
 175                                 stale++;
 176                         if (i > 0)
 177                                 XFS_WANT_CORRUPTED_RETURN(
 178                                         be32_to_cpu(lep[i].hashval) >=
 179                                                 be32_to_cpu(lep[i - 1].hashval));
 180                 }
 181                 XFS_WANT_CORRUPTED_RETURN(count ==
 182                         be32_to_cpu(btp->count) - be32_to_cpu(btp->stale));
 183                 XFS_WANT_CORRUPTED_RETURN(stale == be32_to_cpu(btp->stale));
 184         }
 185         return 0;
 186 }
 187
 188 static void
 189 xfs_dir2_data_verify(
 190         struct xfs_buf          *bp)
 191 {
 192         struct xfs_mount        *mp = bp->b_target->bt_mount;
 193         struct xfs_dir2_data_hdr *hdr = bp->b_addr;
 194         int                     block_ok = 0;
 195
 196         block_ok = hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC);
 197         block_ok = block_ok && __xfs_dir2_data_check(NULL, bp) == 0;
 198
 199         if (!block_ok) {
 200                 XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, hdr);
 201                 xfs_buf_ioerror(bp, EFSCORRUPTED);
 202         }
 203
 204         bp->b_iodone = NULL;
 205         xfs_buf_ioend(bp, 0);
 206 }
 207
 208 int
 209 xfs_dir2_data_read(
 210         struct xfs_trans        *tp,
 211         struct xfs_inode        *dp,
 212         xfs_dablk_t             bno,
 213         xfs_daddr_t             mapped_bno,
 214         struct xfs_buf          **bpp)
 215 {
 216         return xfs_da_read_buf(tp, dp, bno, mapped_bno, bpp,
 217                                         XFS_DATA_FORK, xfs_dir2_data_verify);
 218 }
 219
 220 /*
 221  * Given a data block and an unused entry from that block,
 222  * return the bestfree entry if any that corresponds to it.
 223  */
 224 STATIC xfs_dir2_data_free_t *
 225 xfs_dir2_data_freefind(
 226         xfs_dir2_data_hdr_t     *hdr,           /* data block */
 227         xfs_dir2_data_unused_t  *dup)           /* data unused entry */
 228 {
 229         xfs_dir2_data_free_t    *dfp;           /* bestfree entry */
 230         xfs_dir2_data_aoff_t    off;            /* offset value needed */
 231 #if defined(DEBUG) && defined(__KERNEL__)
 232         int                     matched;        /* matched the value */
 233         int                     seenzero;       /* saw a 0 bestfree entry */
 234 #endif
 235
 236         off = (xfs_dir2_data_aoff_t)((char *)dup - (char *)hdr);
 237 #if defined(DEBUG) && defined(__KERNEL__)
 238         /*
 239          * Validate some consistency in the bestfree table.
 240          * Check order, non-overlapping entries, and if we find the
 241          * one we're looking for it has to be exact.
 242          */
 243         ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
 244                hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC));
 245         for (dfp = &hdr->bestfree[0], seenzero = matched = 0;
 246              dfp < &hdr->bestfree[XFS_DIR2_DATA_FD_COUNT];
 247              dfp++) {
 248                 if (!dfp->offset) {
 249                         ASSERT(!dfp->length);
 250                         seenzero = 1;
 251                         continue;
 252                 }
 253                 ASSERT(seenzero == 0);
 254                 if (be16_to_cpu(dfp->offset) == off) {
 255                         matched = 1;
 256                         ASSERT(dfp->length == dup->length);
 257                 } else if (off < be16_to_cpu(dfp->offset))
 258                         ASSERT(off + be16_to_cpu(dup->length) <= be16_to_cpu(dfp->offset));
 259                 else
 260                         ASSERT(be16_to_cpu(dfp->offset) + be16_to_cpu(dfp->length) <= off);
 261                 ASSERT(matched || be16_to_cpu(dfp->length) >= be16_to_cpu(dup->length));
 262                 if (dfp > &hdr->bestfree[0])
 263                         ASSERT(be16_to_cpu(dfp[-1].length) >= be16_to_cpu(dfp[0].length));
 264         }
 265 #endif
 266         /*
 267          * If this is smaller than the smallest bestfree entry,
 268          * it can't be there since they're sorted.
 269          */
 270         if (be16_to_cpu(dup->length) <
 271             be16_to_cpu(hdr->bestfree[XFS_DIR2_DATA_FD_COUNT - 1].length))
 272                 return NULL;
 273         /*
 274          * Look at the three bestfree entries for our guy.
 275          */
 276         for (dfp = &hdr->bestfree[0];
 277              dfp < &hdr->bestfree[XFS_DIR2_DATA_FD_COUNT];
 278              dfp++) {
 279                 if (!dfp->offset)
 280                         return NULL;
 281                 if (be16_to_cpu(dfp->offset) == off)
 282                         return dfp;
 283         }
 284         /*
 285          * Didn't find it.  This only happens if there are duplicate lengths.
 286          */
 287         return NULL;
 288 }
 289
 290 /*
 291  * Insert an unused-space entry into the bestfree table.
 292  */
 293 xfs_dir2_data_free_t *                          /* entry inserted */
 294 xfs_dir2_data_freeinsert(
 295         xfs_dir2_data_hdr_t     *hdr,           /* data block pointer */
 296         xfs_dir2_data_unused_t  *dup,           /* unused space */
 297         int                     *loghead)       /* log the data header (out) */
 298 {
 299         xfs_dir2_data_free_t    *dfp;           /* bestfree table pointer */
 300         xfs_dir2_data_free_t    new;            /* new bestfree entry */
 301
 302 #ifdef __KERNEL__
 303         ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
 304                hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC));
 305 #endif
 306         dfp = hdr->bestfree;
 307         new.length = dup->length;
 308         new.offset = cpu_to_be16((char *)dup - (char *)hdr);
 309
 310         /*
 311          * Insert at position 0, 1, or 2; or not at all.
 312          */
 313         if (be16_to_cpu(new.length) > be16_to_cpu(dfp[0].length)) {
 314                 dfp[2] = dfp[1];
 315                 dfp[1] = dfp[0];
 316                 dfp[0] = new;
 317                 *loghead = 1;
 318                 return &dfp[0];
 319         }
 320         if (be16_to_cpu(new.length) > be16_to_cpu(dfp[1].length)) {
 321                 dfp[2] = dfp[1];
 322                 dfp[1] = new;
 323                 *loghead = 1;
 324                 return &dfp[1];
 325         }
 326         if (be16_to_cpu(new.length) > be16_to_cpu(dfp[2].length)) {
 327                 dfp[2] = new;
 328                 *loghead = 1;
 329                 return &dfp[2];
 330         }
 331         return NULL;
 332 }
 333
 334 /*
 335  * Remove a bestfree entry from the table.
 336  */
 337 STATIC void
 338 xfs_dir2_data_freeremove(
 339         xfs_dir2_data_hdr_t     *hdr,           /* data block header */
 340         xfs_dir2_data_free_t    *dfp,           /* bestfree entry pointer */
 341         int                     *loghead)       /* out: log data header */
 342 {
 343 #ifdef __KERNEL__
 344         ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
 345                hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC));
 346 #endif
 347         /*
 348          * It's the first entry, slide the next 2 up.
 349          */
 350         if (dfp == &hdr->bestfree[0]) {
 351                 hdr->bestfree[0] = hdr->bestfree[1];
 352                 hdr->bestfree[1] = hdr->bestfree[2];
 353         }
 354         /*
 355          * It's the second entry, slide the 3rd entry up.
 356          */
 357         else if (dfp == &hdr->bestfree[1])
 358                 hdr->bestfree[1] = hdr->bestfree[2];
 359         /*
 360          * Must be the last entry.
 361          */
 362         else
 363                 ASSERT(dfp == &hdr->bestfree[2]);
 364         /*
 365          * Clear the 3rd entry, must be zero now.
 366          */
 367         hdr->bestfree[2].length = 0;
 368         hdr->bestfree[2].offset = 0;
 369         *loghead = 1;
 370 }
 371
 372 /*
 373  * Given a data block, reconstruct its bestfree map.
 374  */
 375 void
 376 xfs_dir2_data_freescan(
 377         xfs_mount_t             *mp,            /* filesystem mount point */
 378         xfs_dir2_data_hdr_t     *hdr,           /* data block header */
 379         int                     *loghead)       /* out: log data header */
 380 {
 381         xfs_dir2_block_tail_t   *btp;           /* block tail */
 382         xfs_dir2_data_entry_t   *dep;           /* active data entry */
 383         xfs_dir2_data_unused_t  *dup;           /* unused data entry */
 384         char                    *endp;          /* end of block's data */
 385         char                    *p;             /* current entry pointer */
 386
 387 #ifdef __KERNEL__
 388         ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
 389                hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC));
 390 #endif
 391         /*
 392          * Start by clearing the table.
 393          */
 394         memset(hdr->bestfree, 0, sizeof(hdr->bestfree));
 395         *loghead = 1;
 396         /*
 397          * Set up pointers.
 398          */
 399         p = (char *)(hdr + 1);
 400         if (hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC)) {
 401                 btp = xfs_dir2_block_tail_p(mp, hdr);
 402                 endp = (char *)xfs_dir2_block_leaf_p(btp);
 403         } else
 404                 endp = (char *)hdr + mp->m_dirblksize;
 405         /*
 406          * Loop over the block's entries.
 407          */
 408         while (p < endp) {
 409                 dup = (xfs_dir2_data_unused_t *)p;
 410                 /*
 411                  * If it's a free entry, insert it.
 412                  */
 413                 if (be16_to_cpu(dup->freetag) == XFS_DIR2_DATA_FREE_TAG) {
 414                         ASSERT((char *)dup - (char *)hdr ==
 415                                be16_to_cpu(*xfs_dir2_data_unused_tag_p(dup)));
 416                         xfs_dir2_data_freeinsert(hdr, dup, loghead);
 417                         p += be16_to_cpu(dup->length);
 418                 }
 419                 /*
 420                  * For active entries, check their tags and skip them.
 421                  */
 422                 else {
 423                         dep = (xfs_dir2_data_entry_t *)p;
 424                         ASSERT((char *)dep - (char *)hdr ==
 425                                be16_to_cpu(*xfs_dir2_data_entry_tag_p(dep)));
 426                         p += xfs_dir2_data_entsize(dep->namelen);
 427                 }
 428         }
 429 }
 430
 431 /*
 432  * Initialize a data block at the given block number in the directory.
 433  * Give back the buffer for the created block.
 434  */
 435 int                                             /* error */
 436 xfs_dir2_data_init(
 437         xfs_da_args_t           *args,          /* directory operation args */
 438         xfs_dir2_db_t           blkno,          /* logical dir block number */
 439         struct xfs_buf          **bpp)          /* output block buffer */
 440 {
 441         struct xfs_buf          *bp;            /* block buffer */
 442         xfs_dir2_data_hdr_t     *hdr;           /* data block header */
 443         xfs_inode_t             *dp;            /* incore directory inode */
 444         xfs_dir2_data_unused_t  *dup;           /* unused entry pointer */
 445         int                     error;          /* error return value */
 446         int                     i;              /* bestfree index */
 447         xfs_mount_t             *mp;            /* filesystem mount point */
 448         xfs_trans_t             *tp;            /* transaction pointer */
 449         int                     t;              /* temp */
 450
 451         dp = args->dp;
 452         mp = dp->i_mount;
 453         tp = args->trans;
 454         /*
 455          * Get the buffer set up for the block.
 456          */
 457         error = xfs_da_get_buf(tp, dp, xfs_dir2_db_to_da(mp, blkno), -1, &bp,
 458                 XFS_DATA_FORK);
 459         if (error) {
 460                 return error;
 461         }
 462         ASSERT(bp != NULL);
 463
 464         /*
 465          * Initialize the header.
 466          */
 467         hdr = bp->b_addr;
 468         hdr->magic = cpu_to_be32(XFS_DIR2_DATA_MAGIC);
 469         hdr->bestfree[0].offset = cpu_to_be16(sizeof(*hdr));
 470         for (i = 1; i < XFS_DIR2_DATA_FD_COUNT; i++) {
 471                 hdr->bestfree[i].length = 0;
 472                 hdr->bestfree[i].offset = 0;
 473         }
 474
 475         /*
 476          * Set up an unused entry for the block's body.
 477          */
 478         dup = (xfs_dir2_data_unused_t *)(hdr + 1);
 479         dup->freetag = cpu_to_be16(XFS_DIR2_DATA_FREE_TAG);
 480
 481         t = mp->m_dirblksize - (uint)sizeof(*hdr);
 482         hdr->bestfree[0].length = cpu_to_be16(t);
 483         dup->length = cpu_to_be16(t);
 484         *xfs_dir2_data_unused_tag_p(dup) = cpu_to_be16((char *)dup - (char *)hdr);
 485         /*
 486          * Log it and return it.
 487          */
 488         xfs_dir2_data_log_header(tp, bp);
 489         xfs_dir2_data_log_unused(tp, bp, dup);
 490         *bpp = bp;
 491         return 0;
 492 }
 493
 494 /*
 495  * Log an active data entry from the block.
 496  */
 497 void
 498 xfs_dir2_data_log_entry(
 499         struct xfs_trans        *tp,
 500         struct xfs_buf          *bp,
 501         xfs_dir2_data_entry_t   *dep)           /* data entry pointer */
 502 {
 503         xfs_dir2_data_hdr_t     *hdr = bp->b_addr;
 504
 505         ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
 506                hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC));
 507
 508         xfs_trans_log_buf(tp, bp, (uint)((char *)dep - (char *)hdr),
 509                 (uint)((char *)(xfs_dir2_data_entry_tag_p(dep) + 1) -
 510                        (char *)hdr - 1));
 511 }
 512
 513 /*
 514  * Log a data block header.
 515  */
 516 void
 517 xfs_dir2_data_log_header(
 518         struct xfs_trans        *tp,
 519         struct xfs_buf          *bp)
 520 {
 521         xfs_dir2_data_hdr_t     *hdr = bp->b_addr;
 522
 523         ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
 524                hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC));
 525
 526         xfs_trans_log_buf(tp, bp, 0, sizeof(*hdr) - 1);
 527 }
 528
 529 /*
 530  * Log a data unused entry.
 531  */
 532 void
 533 xfs_dir2_data_log_unused(
 534         struct xfs_trans        *tp,
 535         struct xfs_buf          *bp,
 536         xfs_dir2_data_unused_t  *dup)           /* data unused pointer */
 537 {
 538         xfs_dir2_data_hdr_t     *hdr = bp->b_addr;
 539
 540         ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
 541                hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC));
 542
 543         /*
 544          * Log the first part of the unused entry.
 545          */
 546         xfs_trans_log_buf(tp, bp, (uint)((char *)dup - (char *)hdr),
 547                 (uint)((char *)&dup->length + sizeof(dup->length) -
 548                        1 - (char *)hdr));
 549         /*
 550          * Log the end (tag) of the unused entry.
 551          */
 552         xfs_trans_log_buf(tp, bp,
 553                 (uint)((char *)xfs_dir2_data_unused_tag_p(dup) - (char *)hdr),
 554                 (uint)((char *)xfs_dir2_data_unused_tag_p(dup) - (char *)hdr +
 555                        sizeof(xfs_dir2_data_off_t) - 1));
 556 }
 557
 558 /*
 559  * Make a byte range in the data block unused.
 560  * Its current contents are unimportant.
 561  */
 562 void
 563 xfs_dir2_data_make_free(
 564         struct xfs_trans        *tp,
 565         struct xfs_buf          *bp,
 566         xfs_dir2_data_aoff_t    offset,         /* starting byte offset */
 567         xfs_dir2_data_aoff_t    len,            /* length in bytes */
 568         int                     *needlogp,      /* out: log header */
 569         int                     *needscanp)     /* out: regen bestfree */
 570 {
 571         xfs_dir2_data_hdr_t     *hdr;           /* data block pointer */
 572         xfs_dir2_data_free_t    *dfp;           /* bestfree pointer */
 573         char                    *endptr;        /* end of data area */
 574         xfs_mount_t             *mp;            /* filesystem mount point */
 575         int                     needscan;       /* need to regen bestfree */
 576         xfs_dir2_data_unused_t  *newdup;        /* new unused entry */
 577         xfs_dir2_data_unused_t  *postdup;       /* unused entry after us */
 578         xfs_dir2_data_unused_t  *prevdup;       /* unused entry before us */
 579
 580         mp = tp->t_mountp;
 581         hdr = bp->b_addr;
 582
 583         /*
 584          * Figure out where the end of the data area is.
 585          */
 586         if (hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC))
 587                 endptr = (char *)hdr + mp->m_dirblksize;
 588         else {
 589                 xfs_dir2_block_tail_t   *btp;   /* block tail */
 590
 591                 ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC));
 592                 btp = xfs_dir2_block_tail_p(mp, hdr);
 593                 endptr = (char *)xfs_dir2_block_leaf_p(btp);
 594         }
 595         /*
 596          * If this isn't the start of the block, then back up to
 597          * the previous entry and see if it's free.
 598          */
 599         if (offset > sizeof(*hdr)) {
 600                 __be16                  *tagp;  /* tag just before us */
 601
 602                 tagp = (__be16 *)((char *)hdr + offset) - 1;
 603                 prevdup = (xfs_dir2_data_unused_t *)((char *)hdr + be16_to_cpu(*tagp));
 604                 if (be16_to_cpu(prevdup->freetag) != XFS_DIR2_DATA_FREE_TAG)
 605                         prevdup = NULL;
 606         } else
 607                 prevdup = NULL;
 608         /*
 609          * If this isn't the end of the block, see if the entry after
 610          * us is free.
 611          */
 612         if ((char *)hdr + offset + len < endptr) {
 613                 postdup =
 614                         (xfs_dir2_data_unused_t *)((char *)hdr + offset + len);
 615                 if (be16_to_cpu(postdup->freetag) != XFS_DIR2_DATA_FREE_TAG)
 616                         postdup = NULL;
 617         } else
 618                 postdup = NULL;
 619         ASSERT(*needscanp == 0);
 620         needscan = 0;
 621         /*
 622          * Previous and following entries are both free,
 623          * merge everything into a single free entry.
 624          */
 625         if (prevdup && postdup) {
 626                 xfs_dir2_data_free_t    *dfp2;  /* another bestfree pointer */
 627
 628                 /*
 629                  * See if prevdup and/or postdup are in bestfree table.
 630                  */
 631                 dfp = xfs_dir2_data_freefind(hdr, prevdup);
 632                 dfp2 = xfs_dir2_data_freefind(hdr, postdup);
 633                 /*
 634                  * We need a rescan unless there are exactly 2 free entries
 635                  * namely our two.  Then we know what's happening, otherwise
 636                  * since the third bestfree is there, there might be more
 637                  * entries.
 638                  */
 639                 needscan = (hdr->bestfree[2].length != 0);
 640                 /*
 641                  * Fix up the new big freespace.
 642                  */
 643                 be16_add_cpu(&prevdup->length, len + be16_to_cpu(postdup->length));
 644                 *xfs_dir2_data_unused_tag_p(prevdup) =
 645                         cpu_to_be16((char *)prevdup - (char *)hdr);
 646                 xfs_dir2_data_log_unused(tp, bp, prevdup);
 647                 if (!needscan) {
 648                         /*
 649                          * Has to be the case that entries 0 and 1 are
 650                          * dfp and dfp2 (don't know which is which), and
 651                          * entry 2 is empty.
 652                          * Remove entry 1 first then entry 0.
 653                          */
 654                         ASSERT(dfp && dfp2);
 655                         if (dfp == &hdr->bestfree[1]) {
 656                                 dfp = &hdr->bestfree[0];
 657                                 ASSERT(dfp2 == dfp);
 658                                 dfp2 = &hdr->bestfree[1];
 659                         }
 660                         xfs_dir2_data_freeremove(hdr, dfp2, needlogp);
 661                         xfs_dir2_data_freeremove(hdr, dfp, needlogp);
 662                         /*
 663                          * Now insert the new entry.
 664                          */
 665                         dfp = xfs_dir2_data_freeinsert(hdr, prevdup, needlogp);
 666                         ASSERT(dfp == &hdr->bestfree[0]);
 667                         ASSERT(dfp->length == prevdup->length);
 668                         ASSERT(!dfp[1].length);
 669                         ASSERT(!dfp[2].length);
 670                 }
 671         }
 672         /*
 673          * The entry before us is free, merge with it.
 674          */
 675         else if (prevdup) {
 676                 dfp = xfs_dir2_data_freefind(hdr, prevdup);
 677                 be16_add_cpu(&prevdup->length, len);
 678                 *xfs_dir2_data_unused_tag_p(prevdup) =
 679                         cpu_to_be16((char *)prevdup - (char *)hdr);
 680                 xfs_dir2_data_log_unused(tp, bp, prevdup);
 681                 /*
 682                  * If the previous entry was in the table, the new entry
 683                  * is longer, so it will be in the table too.  Remove
 684                  * the old one and add the new one.
 685                  */
 686                 if (dfp) {
 687                         xfs_dir2_data_freeremove(hdr, dfp, needlogp);
 688                         xfs_dir2_data_freeinsert(hdr, prevdup, needlogp);
 689                 }
 690                 /*
 691                  * Otherwise we need a scan if the new entry is big enough.
 692                  */
 693                 else {
 694                         needscan = be16_to_cpu(prevdup->length) >
 695                                    be16_to_cpu(hdr->bestfree[2].length);
 696                 }
 697         }
 698         /*
 699          * The following entry is free, merge with it.
 700          */
 701         else if (postdup) {
 702                 dfp = xfs_dir2_data_freefind(hdr, postdup);
 703                 newdup = (xfs_dir2_data_unused_t *)((char *)hdr + offset);
 704                 newdup->freetag = cpu_to_be16(XFS_DIR2_DATA_FREE_TAG);
 705                 newdup->length = cpu_to_be16(len + be16_to_cpu(postdup->length));
 706                 *xfs_dir2_data_unused_tag_p(newdup) =
 707                         cpu_to_be16((char *)newdup - (char *)hdr);
 708                 xfs_dir2_data_log_unused(tp, bp, newdup);
 709                 /*
 710                  * If the following entry was in the table, the new entry
 711                  * is longer, so it will be in the table too.  Remove
 712                  * the old one and add the new one.
 713                  */
 714                 if (dfp) {
 715                         xfs_dir2_data_freeremove(hdr, dfp, needlogp);
 716                         xfs_dir2_data_freeinsert(hdr, newdup, needlogp);
 717                 }
 718                 /*
 719                  * Otherwise we need a scan if the new entry is big enough.
 720                  */
 721                 else {
 722                         needscan = be16_to_cpu(newdup->length) >
 723                                    be16_to_cpu(hdr->bestfree[2].length);
 724                 }
 725         }
 726         /*
 727          * Neither neighbor is free.  Make a new entry.
 728          */
 729         else {
 730                 newdup = (xfs_dir2_data_unused_t *)((char *)hdr + offset);
 731                 newdup->freetag = cpu_to_be16(XFS_DIR2_DATA_FREE_TAG);
 732                 newdup->length = cpu_to_be16(len);
 733                 *xfs_dir2_data_unused_tag_p(newdup) =
 734                         cpu_to_be16((char *)newdup - (char *)hdr);
 735                 xfs_dir2_data_log_unused(tp, bp, newdup);
 736                 xfs_dir2_data_freeinsert(hdr, newdup, needlogp);
 737         }
 738         *needscanp = needscan;
 739 }
 740
 741 /*
 742  * Take a byte range out of an existing unused space and make it un-free.
 743  */
 744 void
 745 xfs_dir2_data_use_free(
 746         struct xfs_trans        *tp,
 747         struct xfs_buf          *bp,
 748         xfs_dir2_data_unused_t  *dup,           /* unused entry */
 749         xfs_dir2_data_aoff_t    offset,         /* starting offset to use */
 750         xfs_dir2_data_aoff_t    len,            /* length to use */
 751         int                     *needlogp,      /* out: need to log header */
 752         int                     *needscanp)     /* out: need regen bestfree */
 753 {
 754         xfs_dir2_data_hdr_t     *hdr;           /* data block header */
 755         xfs_dir2_data_free_t    *dfp;           /* bestfree pointer */
 756         int                     matchback;      /* matches end of freespace */
 757         int                     matchfront;     /* matches start of freespace */
 758         int                     needscan;       /* need to regen bestfree */
 759         xfs_dir2_data_unused_t  *newdup;        /* new unused entry */
 760         xfs_dir2_data_unused_t  *newdup2;       /* another new unused entry */
 761         int                     oldlen;         /* old unused entry's length */
 762
 763         hdr = bp->b_addr;
 764         ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
 765                hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC));
 766         ASSERT(be16_to_cpu(dup->freetag) == XFS_DIR2_DATA_FREE_TAG);
 767         ASSERT(offset >= (char *)dup - (char *)hdr);
 768         ASSERT(offset + len <= (char *)dup + be16_to_cpu(dup->length) - (char *)hdr);
 769         ASSERT((char *)dup - (char *)hdr == be16_to_cpu(*xfs_dir2_data_unused_tag_p(dup)));
 770         /*
 771          * Look up the entry in the bestfree table.
 772          */
 773         dfp = xfs_dir2_data_freefind(hdr, dup);
 774         oldlen = be16_to_cpu(dup->length);
 775         ASSERT(dfp || oldlen <= be16_to_cpu(hdr->bestfree[2].length));
 776         /*
 777          * Check for alignment with front and back of the entry.
 778          */
 779         matchfront = (char *)dup - (char *)hdr == offset;
 780         matchback = (char *)dup + oldlen - (char *)hdr == offset + len;
 781         ASSERT(*needscanp == 0);
 782         needscan = 0;
 783         /*
 784          * If we matched it exactly we just need to get rid of it from
 785          * the bestfree table.
 786          */
 787         if (matchfront && matchback) {
 788                 if (dfp) {
 789                         needscan = (hdr->bestfree[2].offset != 0);
 790                         if (!needscan)
 791                                 xfs_dir2_data_freeremove(hdr, dfp, needlogp);
 792                 }
 793         }
 794         /*
 795          * We match the first part of the entry.
 796          * Make a new entry with the remaining freespace.
 797          */
 798         else if (matchfront) {
 799                 newdup = (xfs_dir2_data_unused_t *)((char *)hdr + offset + len);
 800                 newdup->freetag = cpu_to_be16(XFS_DIR2_DATA_FREE_TAG);
 801                 newdup->length = cpu_to_be16(oldlen - len);
 802                 *xfs_dir2_data_unused_tag_p(newdup) =
 803                         cpu_to_be16((char *)newdup - (char *)hdr);
 804                 xfs_dir2_data_log_unused(tp, bp, newdup);
 805                 /*
 806                  * If it was in the table, remove it and add the new one.
 807                  */
 808                 if (dfp) {
 809                         xfs_dir2_data_freeremove(hdr, dfp, needlogp);
 810                         dfp = xfs_dir2_data_freeinsert(hdr, newdup, needlogp);
 811                         ASSERT(dfp != NULL);
 812                         ASSERT(dfp->length == newdup->length);
 813                         ASSERT(be16_to_cpu(dfp->offset) == (char *)newdup - (char *)hdr);
 814                         /*
 815                          * If we got inserted at the last slot,
 816                          * that means we don't know if there was a better
 817                          * choice for the last slot, or not.  Rescan.
 818                          */
 819                         needscan = dfp == &hdr->bestfree[2];
 820                 }
 821         }
 822         /*
 823          * We match the last part of the entry.
 824          * Trim the allocated space off the tail of the entry.
 825          */
 826         else if (matchback) {
 827                 newdup = dup;
 828                 newdup->length = cpu_to_be16(((char *)hdr + offset) - (char *)newdup);
 829                 *xfs_dir2_data_unused_tag_p(newdup) =
 830                         cpu_to_be16((char *)newdup - (char *)hdr);
 831                 xfs_dir2_data_log_unused(tp, bp, newdup);
 832                 /*
 833                  * If it was in the table, remove it and add the new one.
 834                  */
 835                 if (dfp) {
 836                         xfs_dir2_data_freeremove(hdr, dfp, needlogp);
 837                         dfp = xfs_dir2_data_freeinsert(hdr, newdup, needlogp);
 838                         ASSERT(dfp != NULL);
 839                         ASSERT(dfp->length == newdup->length);
 840                         ASSERT(be16_to_cpu(dfp->offset) == (char *)newdup - (char *)hdr);
 841                         /*
 842                          * If we got inserted at the last slot,
 843                          * that means we don't know if there was a better
 844                          * choice for the last slot, or not.  Rescan.
 845                          */
 846                         needscan = dfp == &hdr->bestfree[2];
 847                 }
 848         }
 849         /*
 850          * Poking out the middle of an entry.
 851          * Make two new entries.
 852          */
 853         else {
 854                 newdup = dup;
 855                 newdup->length = cpu_to_be16(((char *)hdr + offset) - (char *)newdup);
 856                 *xfs_dir2_data_unused_tag_p(newdup) =
 857                         cpu_to_be16((char *)newdup - (char *)hdr);
 858                 xfs_dir2_data_log_unused(tp, bp, newdup);
 859                 newdup2 = (xfs_dir2_data_unused_t *)((char *)hdr + offset + len);
 860                 newdup2->freetag = cpu_to_be16(XFS_DIR2_DATA_FREE_TAG);
 861                 newdup2->length = cpu_to_be16(oldlen - len - be16_to_cpu(newdup->length));
 862                 *xfs_dir2_data_unused_tag_p(newdup2) =
 863                         cpu_to_be16((char *)newdup2 - (char *)hdr);
 864                 xfs_dir2_data_log_unused(tp, bp, newdup2);
 865                 /*
 866                  * If the old entry was in the table, we need to scan
 867                  * if the 3rd entry was valid, since these entries
 868                  * are smaller than the old one.
 869                  * If we don't need to scan that means there were 1 or 2
 870                  * entries in the table, and removing the old and adding
 871                  * the 2 new will work.
 872                  */
 873                 if (dfp) {
 874                         needscan = (hdr->bestfree[2].length != 0);
 875                         if (!needscan) {
 876                                 xfs_dir2_data_freeremove(hdr, dfp, needlogp);
 877                                 xfs_dir2_data_freeinsert(hdr, newdup, needlogp);
 878                                 xfs_dir2_data_freeinsert(hdr, newdup2,
 879                                                          needlogp);
 880                         }
 881                 }
 882         }
 883         *needscanp = needscan;
 884 }