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
 205 void
 206 xfs_dir2_data_write_verify(
 207         struct xfs_buf  *bp)
 208 {
 209         xfs_dir2_data_verify(bp);
 210 }
 211
 212 static void
 213 xfs_dir2_data_read_verify(
 214         struct xfs_buf  *bp)
 215 {
 216         xfs_dir2_data_verify(bp);
 217         bp->b_pre_io = xfs_dir2_data_write_verify;
 218         bp->b_iodone = NULL;
 219         xfs_buf_ioend(bp, 0);
 220 }
 221
 222
 223 int
 224 xfs_dir2_data_read(
 225         struct xfs_trans        *tp,
 226         struct xfs_inode        *dp,
 227         xfs_dablk_t             bno,
 228         xfs_daddr_t             mapped_bno,
 229         struct xfs_buf          **bpp)
 230 {
 231         return xfs_da_read_buf(tp, dp, bno, mapped_bno, bpp,
 232                                 XFS_DATA_FORK, xfs_dir2_data_read_verify);
 233 }
 234
 235 int
 236 xfs_dir2_data_readahead(
 237         struct xfs_trans        *tp,
 238         struct xfs_inode        *dp,
 239         xfs_dablk_t             bno,
 240         xfs_daddr_t             mapped_bno)
 241 {
 242         return xfs_da_reada_buf(tp, dp, bno, mapped_bno,
 243                                 XFS_DATA_FORK, xfs_dir2_data_read_verify);
 244 }
 245
 246 /*
 247  * Given a data block and an unused entry from that block,
 248  * return the bestfree entry if any that corresponds to it.
 249  */
 250 STATIC xfs_dir2_data_free_t *
 251 xfs_dir2_data_freefind(
 252         xfs_dir2_data_hdr_t     *hdr,           /* data block */
 253         xfs_dir2_data_unused_t  *dup)           /* data unused entry */
 254 {
 255         xfs_dir2_data_free_t    *dfp;           /* bestfree entry */
 256         xfs_dir2_data_aoff_t    off;            /* offset value needed */
 257 #if defined(DEBUG) && defined(__KERNEL__)
 258         int                     matched;        /* matched the value */
 259         int                     seenzero;       /* saw a 0 bestfree entry */
 260 #endif
 261
 262         off = (xfs_dir2_data_aoff_t)((char *)dup - (char *)hdr);
 263 #if defined(DEBUG) && defined(__KERNEL__)
 264         /*
 265          * Validate some consistency in the bestfree table.
 266          * Check order, non-overlapping entries, and if we find the
 267          * one we're looking for it has to be exact.
 268          */
 269         ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
 270                hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC));
 271         for (dfp = &hdr->bestfree[0], seenzero = matched = 0;
 272              dfp < &hdr->bestfree[XFS_DIR2_DATA_FD_COUNT];
 273              dfp++) {
 274                 if (!dfp->offset) {
 275                         ASSERT(!dfp->length);
 276                         seenzero = 1;
 277                         continue;
 278                 }
 279                 ASSERT(seenzero == 0);
 280                 if (be16_to_cpu(dfp->offset) == off) {
 281                         matched = 1;
 282                         ASSERT(dfp->length == dup->length);
 283                 } else if (off < be16_to_cpu(dfp->offset))
 284                         ASSERT(off + be16_to_cpu(dup->length) <= be16_to_cpu(dfp->offset));
 285                 else
 286                         ASSERT(be16_to_cpu(dfp->offset) + be16_to_cpu(dfp->length) <= off);
 287                 ASSERT(matched || be16_to_cpu(dfp->length) >= be16_to_cpu(dup->length));
 288                 if (dfp > &hdr->bestfree[0])
 289                         ASSERT(be16_to_cpu(dfp[-1].length) >= be16_to_cpu(dfp[0].length));
 290         }
 291 #endif
 292         /*
 293          * If this is smaller than the smallest bestfree entry,
 294          * it can't be there since they're sorted.
 295          */
 296         if (be16_to_cpu(dup->length) <
 297             be16_to_cpu(hdr->bestfree[XFS_DIR2_DATA_FD_COUNT - 1].length))
 298                 return NULL;
 299         /*
 300          * Look at the three bestfree entries for our guy.
 301          */
 302         for (dfp = &hdr->bestfree[0];
 303              dfp < &hdr->bestfree[XFS_DIR2_DATA_FD_COUNT];
 304              dfp++) {
 305                 if (!dfp->offset)
 306                         return NULL;
 307                 if (be16_to_cpu(dfp->offset) == off)
 308                         return dfp;
 309         }
 310         /*
 311          * Didn't find it.  This only happens if there are duplicate lengths.
 312          */
 313         return NULL;
 314 }
 315
 316 /*
 317  * Insert an unused-space entry into the bestfree table.
 318  */
 319 xfs_dir2_data_free_t *                          /* entry inserted */
 320 xfs_dir2_data_freeinsert(
 321         xfs_dir2_data_hdr_t     *hdr,           /* data block pointer */
 322         xfs_dir2_data_unused_t  *dup,           /* unused space */
 323         int                     *loghead)       /* log the data header (out) */
 324 {
 325         xfs_dir2_data_free_t    *dfp;           /* bestfree table pointer */
 326         xfs_dir2_data_free_t    new;            /* new bestfree entry */
 327
 328 #ifdef __KERNEL__
 329         ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
 330                hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC));
 331 #endif
 332         dfp = hdr->bestfree;
 333         new.length = dup->length;
 334         new.offset = cpu_to_be16((char *)dup - (char *)hdr);
 335
 336         /*
 337          * Insert at position 0, 1, or 2; or not at all.
 338          */
 339         if (be16_to_cpu(new.length) > be16_to_cpu(dfp[0].length)) {
 340                 dfp[2] = dfp[1];
 341                 dfp[1] = dfp[0];
 342                 dfp[0] = new;
 343                 *loghead = 1;
 344                 return &dfp[0];
 345         }
 346         if (be16_to_cpu(new.length) > be16_to_cpu(dfp[1].length)) {
 347                 dfp[2] = dfp[1];
 348                 dfp[1] = new;
 349                 *loghead = 1;
 350                 return &dfp[1];
 351         }
 352         if (be16_to_cpu(new.length) > be16_to_cpu(dfp[2].length)) {
 353                 dfp[2] = new;
 354                 *loghead = 1;
 355                 return &dfp[2];
 356         }
 357         return NULL;
 358 }
 359
 360 /*
 361  * Remove a bestfree entry from the table.
 362  */
 363 STATIC void
 364 xfs_dir2_data_freeremove(
 365         xfs_dir2_data_hdr_t     *hdr,           /* data block header */
 366         xfs_dir2_data_free_t    *dfp,           /* bestfree entry pointer */
 367         int                     *loghead)       /* out: log data header */
 368 {
 369 #ifdef __KERNEL__
 370         ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
 371                hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC));
 372 #endif
 373         /*
 374          * It's the first entry, slide the next 2 up.
 375          */
 376         if (dfp == &hdr->bestfree[0]) {
 377                 hdr->bestfree[0] = hdr->bestfree[1];
 378                 hdr->bestfree[1] = hdr->bestfree[2];
 379         }
 380         /*
 381          * It's the second entry, slide the 3rd entry up.
 382          */
 383         else if (dfp == &hdr->bestfree[1])
 384                 hdr->bestfree[1] = hdr->bestfree[2];
 385         /*
 386          * Must be the last entry.
 387          */
 388         else
 389                 ASSERT(dfp == &hdr->bestfree[2]);
 390         /*
 391          * Clear the 3rd entry, must be zero now.
 392          */
 393         hdr->bestfree[2].length = 0;
 394         hdr->bestfree[2].offset = 0;
 395         *loghead = 1;
 396 }
 397
 398 /*
 399  * Given a data block, reconstruct its bestfree map.
 400  */
 401 void
 402 xfs_dir2_data_freescan(
 403         xfs_mount_t             *mp,            /* filesystem mount point */
 404         xfs_dir2_data_hdr_t     *hdr,           /* data block header */
 405         int                     *loghead)       /* out: log data header */
 406 {
 407         xfs_dir2_block_tail_t   *btp;           /* block tail */
 408         xfs_dir2_data_entry_t   *dep;           /* active data entry */
 409         xfs_dir2_data_unused_t  *dup;           /* unused data entry */
 410         char                    *endp;          /* end of block's data */
 411         char                    *p;             /* current entry pointer */
 412
 413 #ifdef __KERNEL__
 414         ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
 415                hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC));
 416 #endif
 417         /*
 418          * Start by clearing the table.
 419          */
 420         memset(hdr->bestfree, 0, sizeof(hdr->bestfree));
 421         *loghead = 1;
 422         /*
 423          * Set up pointers.
 424          */
 425         p = (char *)(hdr + 1);
 426         if (hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC)) {
 427                 btp = xfs_dir2_block_tail_p(mp, hdr);
 428                 endp = (char *)xfs_dir2_block_leaf_p(btp);
 429         } else
 430                 endp = (char *)hdr + mp->m_dirblksize;
 431         /*
 432          * Loop over the block's entries.
 433          */
 434         while (p < endp) {
 435                 dup = (xfs_dir2_data_unused_t *)p;
 436                 /*
 437                  * If it's a free entry, insert it.
 438                  */
 439                 if (be16_to_cpu(dup->freetag) == XFS_DIR2_DATA_FREE_TAG) {
 440                         ASSERT((char *)dup - (char *)hdr ==
 441                                be16_to_cpu(*xfs_dir2_data_unused_tag_p(dup)));
 442                         xfs_dir2_data_freeinsert(hdr, dup, loghead);
 443                         p += be16_to_cpu(dup->length);
 444                 }
 445                 /*
 446                  * For active entries, check their tags and skip them.
 447                  */
 448                 else {
 449                         dep = (xfs_dir2_data_entry_t *)p;
 450                         ASSERT((char *)dep - (char *)hdr ==
 451                                be16_to_cpu(*xfs_dir2_data_entry_tag_p(dep)));
 452                         p += xfs_dir2_data_entsize(dep->namelen);
 453                 }
 454         }
 455 }
 456
 457 /*
 458  * Initialize a data block at the given block number in the directory.
 459  * Give back the buffer for the created block.
 460  */
 461 int                                             /* error */
 462 xfs_dir2_data_init(
 463         xfs_da_args_t           *args,          /* directory operation args */
 464         xfs_dir2_db_t           blkno,          /* logical dir block number */
 465         struct xfs_buf          **bpp)          /* output block buffer */
 466 {
 467         struct xfs_buf          *bp;            /* block buffer */
 468         xfs_dir2_data_hdr_t     *hdr;           /* data block header */
 469         xfs_inode_t             *dp;            /* incore directory inode */
 470         xfs_dir2_data_unused_t  *dup;           /* unused entry pointer */
 471         int                     error;          /* error return value */
 472         int                     i;              /* bestfree index */
 473         xfs_mount_t             *mp;            /* filesystem mount point */
 474         xfs_trans_t             *tp;            /* transaction pointer */
 475         int                     t;              /* temp */
 476
 477         dp = args->dp;
 478         mp = dp->i_mount;
 479         tp = args->trans;
 480         /*
 481          * Get the buffer set up for the block.
 482          */
 483         error = xfs_da_get_buf(tp, dp, xfs_dir2_db_to_da(mp, blkno), -1, &bp,
 484                 XFS_DATA_FORK);
 485         if (error)
 486                 return error;
 487         bp->b_pre_io = xfs_dir2_data_write_verify;
 488
 489         /*
 490          * Initialize the header.
 491          */
 492         hdr = bp->b_addr;
 493         hdr->magic = cpu_to_be32(XFS_DIR2_DATA_MAGIC);
 494         hdr->bestfree[0].offset = cpu_to_be16(sizeof(*hdr));
 495         for (i = 1; i < XFS_DIR2_DATA_FD_COUNT; i++) {
 496                 hdr->bestfree[i].length = 0;
 497                 hdr->bestfree[i].offset = 0;
 498         }
 499
 500         /*
 501          * Set up an unused entry for the block's body.
 502          */
 503         dup = (xfs_dir2_data_unused_t *)(hdr + 1);
 504         dup->freetag = cpu_to_be16(XFS_DIR2_DATA_FREE_TAG);
 505
 506         t = mp->m_dirblksize - (uint)sizeof(*hdr);
 507         hdr->bestfree[0].length = cpu_to_be16(t);
 508         dup->length = cpu_to_be16(t);
 509         *xfs_dir2_data_unused_tag_p(dup) = cpu_to_be16((char *)dup - (char *)hdr);
 510         /*
 511          * Log it and return it.
 512          */
 513         xfs_dir2_data_log_header(tp, bp);
 514         xfs_dir2_data_log_unused(tp, bp, dup);
 515         *bpp = bp;
 516         return 0;
 517 }
 518
 519 /*
 520  * Log an active data entry from the block.
 521  */
 522 void
 523 xfs_dir2_data_log_entry(
 524         struct xfs_trans        *tp,
 525         struct xfs_buf          *bp,
 526         xfs_dir2_data_entry_t   *dep)           /* data entry pointer */
 527 {
 528         xfs_dir2_data_hdr_t     *hdr = bp->b_addr;
 529
 530         ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
 531                hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC));
 532
 533         xfs_trans_log_buf(tp, bp, (uint)((char *)dep - (char *)hdr),
 534                 (uint)((char *)(xfs_dir2_data_entry_tag_p(dep) + 1) -
 535                        (char *)hdr - 1));
 536 }
 537
 538 /*
 539  * Log a data block header.
 540  */
 541 void
 542 xfs_dir2_data_log_header(
 543         struct xfs_trans        *tp,
 544         struct xfs_buf          *bp)
 545 {
 546         xfs_dir2_data_hdr_t     *hdr = bp->b_addr;
 547
 548         ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
 549                hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC));
 550
 551         xfs_trans_log_buf(tp, bp, 0, sizeof(*hdr) - 1);
 552 }
 553
 554 /*
 555  * Log a data unused entry.
 556  */
 557 void
 558 xfs_dir2_data_log_unused(
 559         struct xfs_trans        *tp,
 560         struct xfs_buf          *bp,
 561         xfs_dir2_data_unused_t  *dup)           /* data unused pointer */
 562 {
 563         xfs_dir2_data_hdr_t     *hdr = bp->b_addr;
 564
 565         ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
 566                hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC));
 567
 568         /*
 569          * Log the first part of the unused entry.
 570          */
 571         xfs_trans_log_buf(tp, bp, (uint)((char *)dup - (char *)hdr),
 572                 (uint)((char *)&dup->length + sizeof(dup->length) -
 573                        1 - (char *)hdr));
 574         /*
 575          * Log the end (tag) of the unused entry.
 576          */
 577         xfs_trans_log_buf(tp, bp,
 578                 (uint)((char *)xfs_dir2_data_unused_tag_p(dup) - (char *)hdr),
 579                 (uint)((char *)xfs_dir2_data_unused_tag_p(dup) - (char *)hdr +
 580                        sizeof(xfs_dir2_data_off_t) - 1));
 581 }
 582
 583 /*
 584  * Make a byte range in the data block unused.
 585  * Its current contents are unimportant.
 586  */
 587 void
 588 xfs_dir2_data_make_free(
 589         struct xfs_trans        *tp,
 590         struct xfs_buf          *bp,
 591         xfs_dir2_data_aoff_t    offset,         /* starting byte offset */
 592         xfs_dir2_data_aoff_t    len,            /* length in bytes */
 593         int                     *needlogp,      /* out: log header */
 594         int                     *needscanp)     /* out: regen bestfree */
 595 {
 596         xfs_dir2_data_hdr_t     *hdr;           /* data block pointer */
 597         xfs_dir2_data_free_t    *dfp;           /* bestfree pointer */
 598         char                    *endptr;        /* end of data area */
 599         xfs_mount_t             *mp;            /* filesystem mount point */
 600         int                     needscan;       /* need to regen bestfree */
 601         xfs_dir2_data_unused_t  *newdup;        /* new unused entry */
 602         xfs_dir2_data_unused_t  *postdup;       /* unused entry after us */
 603         xfs_dir2_data_unused_t  *prevdup;       /* unused entry before us */
 604
 605         mp = tp->t_mountp;
 606         hdr = bp->b_addr;
 607
 608         /*
 609          * Figure out where the end of the data area is.
 610          */
 611         if (hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC))
 612                 endptr = (char *)hdr + mp->m_dirblksize;
 613         else {
 614                 xfs_dir2_block_tail_t   *btp;   /* block tail */
 615
 616                 ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC));
 617                 btp = xfs_dir2_block_tail_p(mp, hdr);
 618                 endptr = (char *)xfs_dir2_block_leaf_p(btp);
 619         }
 620         /*
 621          * If this isn't the start of the block, then back up to
 622          * the previous entry and see if it's free.
 623          */
 624         if (offset > sizeof(*hdr)) {
 625                 __be16                  *tagp;  /* tag just before us */
 626
 627                 tagp = (__be16 *)((char *)hdr + offset) - 1;
 628                 prevdup = (xfs_dir2_data_unused_t *)((char *)hdr + be16_to_cpu(*tagp));
 629                 if (be16_to_cpu(prevdup->freetag) != XFS_DIR2_DATA_FREE_TAG)
 630                         prevdup = NULL;
 631         } else
 632                 prevdup = NULL;
 633         /*
 634          * If this isn't the end of the block, see if the entry after
 635          * us is free.
 636          */
 637         if ((char *)hdr + offset + len < endptr) {
 638                 postdup =
 639                         (xfs_dir2_data_unused_t *)((char *)hdr + offset + len);
 640                 if (be16_to_cpu(postdup->freetag) != XFS_DIR2_DATA_FREE_TAG)
 641                         postdup = NULL;
 642         } else
 643                 postdup = NULL;
 644         ASSERT(*needscanp == 0);
 645         needscan = 0;
 646         /*
 647          * Previous and following entries are both free,
 648          * merge everything into a single free entry.
 649          */
 650         if (prevdup && postdup) {
 651                 xfs_dir2_data_free_t    *dfp2;  /* another bestfree pointer */
 652
 653                 /*
 654                  * See if prevdup and/or postdup are in bestfree table.
 655                  */
 656                 dfp = xfs_dir2_data_freefind(hdr, prevdup);
 657                 dfp2 = xfs_dir2_data_freefind(hdr, postdup);
 658                 /*
 659                  * We need a rescan unless there are exactly 2 free entries
 660                  * namely our two.  Then we know what's happening, otherwise
 661                  * since the third bestfree is there, there might be more
 662                  * entries.
 663                  */
 664                 needscan = (hdr->bestfree[2].length != 0);
 665                 /*
 666                  * Fix up the new big freespace.
 667                  */
 668                 be16_add_cpu(&prevdup->length, len + be16_to_cpu(postdup->length));
 669                 *xfs_dir2_data_unused_tag_p(prevdup) =
 670                         cpu_to_be16((char *)prevdup - (char *)hdr);
 671                 xfs_dir2_data_log_unused(tp, bp, prevdup);
 672                 if (!needscan) {
 673                         /*
 674                          * Has to be the case that entries 0 and 1 are
 675                          * dfp and dfp2 (don't know which is which), and
 676                          * entry 2 is empty.
 677                          * Remove entry 1 first then entry 0.
 678                          */
 679                         ASSERT(dfp && dfp2);
 680                         if (dfp == &hdr->bestfree[1]) {
 681                                 dfp = &hdr->bestfree[0];
 682                                 ASSERT(dfp2 == dfp);
 683                                 dfp2 = &hdr->bestfree[1];
 684                         }
 685                         xfs_dir2_data_freeremove(hdr, dfp2, needlogp);
 686                         xfs_dir2_data_freeremove(hdr, dfp, needlogp);
 687                         /*
 688                          * Now insert the new entry.
 689                          */
 690                         dfp = xfs_dir2_data_freeinsert(hdr, prevdup, needlogp);
 691                         ASSERT(dfp == &hdr->bestfree[0]);
 692                         ASSERT(dfp->length == prevdup->length);
 693                         ASSERT(!dfp[1].length);
 694                         ASSERT(!dfp[2].length);
 695                 }
 696         }
 697         /*
 698          * The entry before us is free, merge with it.
 699          */
 700         else if (prevdup) {
 701                 dfp = xfs_dir2_data_freefind(hdr, prevdup);
 702                 be16_add_cpu(&prevdup->length, len);
 703                 *xfs_dir2_data_unused_tag_p(prevdup) =
 704                         cpu_to_be16((char *)prevdup - (char *)hdr);
 705                 xfs_dir2_data_log_unused(tp, bp, prevdup);
 706                 /*
 707                  * If the previous entry was in the table, the new entry
 708                  * is longer, so it will be in the table too.  Remove
 709                  * the old one and add the new one.
 710                  */
 711                 if (dfp) {
 712                         xfs_dir2_data_freeremove(hdr, dfp, needlogp);
 713                         xfs_dir2_data_freeinsert(hdr, prevdup, needlogp);
 714                 }
 715                 /*
 716                  * Otherwise we need a scan if the new entry is big enough.
 717                  */
 718                 else {
 719                         needscan = be16_to_cpu(prevdup->length) >
 720                                    be16_to_cpu(hdr->bestfree[2].length);
 721                 }
 722         }
 723         /*
 724          * The following entry is free, merge with it.
 725          */
 726         else if (postdup) {
 727                 dfp = xfs_dir2_data_freefind(hdr, postdup);
 728                 newdup = (xfs_dir2_data_unused_t *)((char *)hdr + offset);
 729                 newdup->freetag = cpu_to_be16(XFS_DIR2_DATA_FREE_TAG);
 730                 newdup->length = cpu_to_be16(len + be16_to_cpu(postdup->length));
 731                 *xfs_dir2_data_unused_tag_p(newdup) =
 732                         cpu_to_be16((char *)newdup - (char *)hdr);
 733                 xfs_dir2_data_log_unused(tp, bp, newdup);
 734                 /*
 735                  * If the following entry was in the table, the new entry
 736                  * is longer, so it will be in the table too.  Remove
 737                  * the old one and add the new one.
 738                  */
 739                 if (dfp) {
 740                         xfs_dir2_data_freeremove(hdr, dfp, needlogp);
 741                         xfs_dir2_data_freeinsert(hdr, newdup, needlogp);
 742                 }
 743                 /*
 744                  * Otherwise we need a scan if the new entry is big enough.
 745                  */
 746                 else {
 747                         needscan = be16_to_cpu(newdup->length) >
 748                                    be16_to_cpu(hdr->bestfree[2].length);
 749                 }
 750         }
 751         /*
 752          * Neither neighbor is free.  Make a new entry.
 753          */
 754         else {
 755                 newdup = (xfs_dir2_data_unused_t *)((char *)hdr + offset);
 756                 newdup->freetag = cpu_to_be16(XFS_DIR2_DATA_FREE_TAG);
 757                 newdup->length = cpu_to_be16(len);
 758                 *xfs_dir2_data_unused_tag_p(newdup) =
 759                         cpu_to_be16((char *)newdup - (char *)hdr);
 760                 xfs_dir2_data_log_unused(tp, bp, newdup);
 761                 xfs_dir2_data_freeinsert(hdr, newdup, needlogp);
 762         }
 763         *needscanp = needscan;
 764 }
 765
 766 /*
 767  * Take a byte range out of an existing unused space and make it un-free.
 768  */
 769 void
 770 xfs_dir2_data_use_free(
 771         struct xfs_trans        *tp,
 772         struct xfs_buf          *bp,
 773         xfs_dir2_data_unused_t  *dup,           /* unused entry */
 774         xfs_dir2_data_aoff_t    offset,         /* starting offset to use */
 775         xfs_dir2_data_aoff_t    len,            /* length to use */
 776         int                     *needlogp,      /* out: need to log header */
 777         int                     *needscanp)     /* out: need regen bestfree */
 778 {
 779         xfs_dir2_data_hdr_t     *hdr;           /* data block header */
 780         xfs_dir2_data_free_t    *dfp;           /* bestfree pointer */
 781         int                     matchback;      /* matches end of freespace */
 782         int                     matchfront;     /* matches start of freespace */
 783         int                     needscan;       /* need to regen bestfree */
 784         xfs_dir2_data_unused_t  *newdup;        /* new unused entry */
 785         xfs_dir2_data_unused_t  *newdup2;       /* another new unused entry */
 786         int                     oldlen;         /* old unused entry's length */
 787
 788         hdr = bp->b_addr;
 789         ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
 790                hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC));
 791         ASSERT(be16_to_cpu(dup->freetag) == XFS_DIR2_DATA_FREE_TAG);
 792         ASSERT(offset >= (char *)dup - (char *)hdr);
 793         ASSERT(offset + len <= (char *)dup + be16_to_cpu(dup->length) - (char *)hdr);
 794         ASSERT((char *)dup - (char *)hdr == be16_to_cpu(*xfs_dir2_data_unused_tag_p(dup)));
 795         /*
 796          * Look up the entry in the bestfree table.
 797          */
 798         dfp = xfs_dir2_data_freefind(hdr, dup);
 799         oldlen = be16_to_cpu(dup->length);
 800         ASSERT(dfp || oldlen <= be16_to_cpu(hdr->bestfree[2].length));
 801         /*
 802          * Check for alignment with front and back of the entry.
 803          */
 804         matchfront = (char *)dup - (char *)hdr == offset;
 805         matchback = (char *)dup + oldlen - (char *)hdr == offset + len;
 806         ASSERT(*needscanp == 0);
 807         needscan = 0;
 808         /*
 809          * If we matched it exactly we just need to get rid of it from
 810          * the bestfree table.
 811          */
 812         if (matchfront && matchback) {
 813                 if (dfp) {
 814                         needscan = (hdr->bestfree[2].offset != 0);
 815                         if (!needscan)
 816                                 xfs_dir2_data_freeremove(hdr, dfp, needlogp);
 817                 }
 818         }
 819         /*
 820          * We match the first part of the entry.
 821          * Make a new entry with the remaining freespace.
 822          */
 823         else if (matchfront) {
 824                 newdup = (xfs_dir2_data_unused_t *)((char *)hdr + offset + len);
 825                 newdup->freetag = cpu_to_be16(XFS_DIR2_DATA_FREE_TAG);
 826                 newdup->length = cpu_to_be16(oldlen - len);
 827                 *xfs_dir2_data_unused_tag_p(newdup) =
 828                         cpu_to_be16((char *)newdup - (char *)hdr);
 829                 xfs_dir2_data_log_unused(tp, bp, newdup);
 830                 /*
 831                  * If it was in the table, remove it and add the new one.
 832                  */
 833                 if (dfp) {
 834                         xfs_dir2_data_freeremove(hdr, dfp, needlogp);
 835                         dfp = xfs_dir2_data_freeinsert(hdr, newdup, needlogp);
 836                         ASSERT(dfp != NULL);
 837                         ASSERT(dfp->length == newdup->length);
 838                         ASSERT(be16_to_cpu(dfp->offset) == (char *)newdup - (char *)hdr);
 839                         /*
 840                          * If we got inserted at the last slot,
 841                          * that means we don't know if there was a better
 842                          * choice for the last slot, or not.  Rescan.
 843                          */
 844                         needscan = dfp == &hdr->bestfree[2];
 845                 }
 846         }
 847         /*
 848          * We match the last part of the entry.
 849          * Trim the allocated space off the tail of the entry.
 850          */
 851         else if (matchback) {
 852                 newdup = dup;
 853                 newdup->length = cpu_to_be16(((char *)hdr + offset) - (char *)newdup);
 854                 *xfs_dir2_data_unused_tag_p(newdup) =
 855                         cpu_to_be16((char *)newdup - (char *)hdr);
 856                 xfs_dir2_data_log_unused(tp, bp, newdup);
 857                 /*
 858                  * If it was in the table, remove it and add the new one.
 859                  */
 860                 if (dfp) {
 861                         xfs_dir2_data_freeremove(hdr, dfp, needlogp);
 862                         dfp = xfs_dir2_data_freeinsert(hdr, newdup, needlogp);
 863                         ASSERT(dfp != NULL);
 864                         ASSERT(dfp->length == newdup->length);
 865                         ASSERT(be16_to_cpu(dfp->offset) == (char *)newdup - (char *)hdr);
 866                         /*
 867                          * If we got inserted at the last slot,
 868                          * that means we don't know if there was a better
 869                          * choice for the last slot, or not.  Rescan.
 870                          */
 871                         needscan = dfp == &hdr->bestfree[2];
 872                 }
 873         }
 874         /*
 875          * Poking out the middle of an entry.
 876          * Make two new entries.
 877          */
 878         else {
 879                 newdup = dup;
 880                 newdup->length = cpu_to_be16(((char *)hdr + offset) - (char *)newdup);
 881                 *xfs_dir2_data_unused_tag_p(newdup) =
 882                         cpu_to_be16((char *)newdup - (char *)hdr);
 883                 xfs_dir2_data_log_unused(tp, bp, newdup);
 884                 newdup2 = (xfs_dir2_data_unused_t *)((char *)hdr + offset + len);
 885                 newdup2->freetag = cpu_to_be16(XFS_DIR2_DATA_FREE_TAG);
 886                 newdup2->length = cpu_to_be16(oldlen - len - be16_to_cpu(newdup->length));
 887                 *xfs_dir2_data_unused_tag_p(newdup2) =
 888                         cpu_to_be16((char *)newdup2 - (char *)hdr);
 889                 xfs_dir2_data_log_unused(tp, bp, newdup2);
 890                 /*
 891                  * If the old entry was in the table, we need to scan
 892                  * if the 3rd entry was valid, since these entries
 893                  * are smaller than the old one.
 894                  * If we don't need to scan that means there were 1 or 2
 895                  * entries in the table, and removing the old and adding
 896                  * the 2 new will work.
 897                  */
 898                 if (dfp) {
 899                         needscan = (hdr->bestfree[2].length != 0);
 900                         if (!needscan) {
 901                                 xfs_dir2_data_freeremove(hdr, dfp, needlogp);
 902                                 xfs_dir2_data_freeinsert(hdr, newdup, needlogp);
 903                                 xfs_dir2_data_freeinsert(hdr, newdup2,
 904                                                          needlogp);
 905                         }
 906                 }
 907         }
 908         *needscanp = needscan;
 909 }