linux/fs/xfs/xfs_ialloc.c
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   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_bit.h"
  22#include "xfs_log.h"
  23#include "xfs_inum.h"
  24#include "xfs_trans.h"
  25#include "xfs_sb.h"
  26#include "xfs_ag.h"
  27#include "xfs_mount.h"
  28#include "xfs_bmap_btree.h"
  29#include "xfs_alloc_btree.h"
  30#include "xfs_ialloc_btree.h"
  31#include "xfs_dinode.h"
  32#include "xfs_inode.h"
  33#include "xfs_btree.h"
  34#include "xfs_ialloc.h"
  35#include "xfs_alloc.h"
  36#include "xfs_rtalloc.h"
  37#include "xfs_error.h"
  38#include "xfs_bmap.h"
  39
  40
  41/*
  42 * Allocation group level functions.
  43 */
  44static inline int
  45xfs_ialloc_cluster_alignment(
  46        xfs_alloc_arg_t *args)
  47{
  48        if (xfs_sb_version_hasalign(&args->mp->m_sb) &&
  49            args->mp->m_sb.sb_inoalignmt >=
  50             XFS_B_TO_FSBT(args->mp, XFS_INODE_CLUSTER_SIZE(args->mp)))
  51                return args->mp->m_sb.sb_inoalignmt;
  52        return 1;
  53}
  54
  55/*
  56 * Lookup a record by ino in the btree given by cur.
  57 */
  58int                                     /* error */
  59xfs_inobt_lookup(
  60        struct xfs_btree_cur    *cur,   /* btree cursor */
  61        xfs_agino_t             ino,    /* starting inode of chunk */
  62        xfs_lookup_t            dir,    /* <=, >=, == */
  63        int                     *stat)  /* success/failure */
  64{
  65        cur->bc_rec.i.ir_startino = ino;
  66        cur->bc_rec.i.ir_freecount = 0;
  67        cur->bc_rec.i.ir_free = 0;
  68        return xfs_btree_lookup(cur, dir, stat);
  69}
  70
  71/*
  72 * Update the record referred to by cur to the value given.
  73 * This either works (return 0) or gets an EFSCORRUPTED error.
  74 */
  75STATIC int                              /* error */
  76xfs_inobt_update(
  77        struct xfs_btree_cur    *cur,   /* btree cursor */
  78        xfs_inobt_rec_incore_t  *irec)  /* btree record */
  79{
  80        union xfs_btree_rec     rec;
  81
  82        rec.inobt.ir_startino = cpu_to_be32(irec->ir_startino);
  83        rec.inobt.ir_freecount = cpu_to_be32(irec->ir_freecount);
  84        rec.inobt.ir_free = cpu_to_be64(irec->ir_free);
  85        return xfs_btree_update(cur, &rec);
  86}
  87
  88/*
  89 * Get the data from the pointed-to record.
  90 */
  91int                                     /* error */
  92xfs_inobt_get_rec(
  93        struct xfs_btree_cur    *cur,   /* btree cursor */
  94        xfs_inobt_rec_incore_t  *irec,  /* btree record */
  95        int                     *stat)  /* output: success/failure */
  96{
  97        union xfs_btree_rec     *rec;
  98        int                     error;
  99
 100        error = xfs_btree_get_rec(cur, &rec, stat);
 101        if (!error && *stat == 1) {
 102                irec->ir_startino = be32_to_cpu(rec->inobt.ir_startino);
 103                irec->ir_freecount = be32_to_cpu(rec->inobt.ir_freecount);
 104                irec->ir_free = be64_to_cpu(rec->inobt.ir_free);
 105        }
 106        return error;
 107}
 108
 109/*
 110 * Verify that the number of free inodes in the AGI is correct.
 111 */
 112#ifdef DEBUG
 113STATIC int
 114xfs_check_agi_freecount(
 115        struct xfs_btree_cur    *cur,
 116        struct xfs_agi          *agi)
 117{
 118        if (cur->bc_nlevels == 1) {
 119                xfs_inobt_rec_incore_t rec;
 120                int             freecount = 0;
 121                int             error;
 122                int             i;
 123
 124                error = xfs_inobt_lookup(cur, 0, XFS_LOOKUP_GE, &i);
 125                if (error)
 126                        return error;
 127
 128                do {
 129                        error = xfs_inobt_get_rec(cur, &rec, &i);
 130                        if (error)
 131                                return error;
 132
 133                        if (i) {
 134                                freecount += rec.ir_freecount;
 135                                error = xfs_btree_increment(cur, 0, &i);
 136                                if (error)
 137                                        return error;
 138                        }
 139                } while (i == 1);
 140
 141                if (!XFS_FORCED_SHUTDOWN(cur->bc_mp))
 142                        ASSERT(freecount == be32_to_cpu(agi->agi_freecount));
 143        }
 144        return 0;
 145}
 146#else
 147#define xfs_check_agi_freecount(cur, agi)       0
 148#endif
 149
 150/*
 151 * Initialise a new set of inodes.
 152 */
 153STATIC int
 154xfs_ialloc_inode_init(
 155        struct xfs_mount        *mp,
 156        struct xfs_trans        *tp,
 157        xfs_agnumber_t          agno,
 158        xfs_agblock_t           agbno,
 159        xfs_agblock_t           length,
 160        unsigned int            gen)
 161{
 162        struct xfs_buf          *fbuf;
 163        struct xfs_dinode       *free;
 164        int                     blks_per_cluster, nbufs, ninodes;
 165        int                     version;
 166        int                     i, j;
 167        xfs_daddr_t             d;
 168
 169        /*
 170         * Loop over the new block(s), filling in the inodes.
 171         * For small block sizes, manipulate the inodes in buffers
 172         * which are multiples of the blocks size.
 173         */
 174        if (mp->m_sb.sb_blocksize >= XFS_INODE_CLUSTER_SIZE(mp)) {
 175                blks_per_cluster = 1;
 176                nbufs = length;
 177                ninodes = mp->m_sb.sb_inopblock;
 178        } else {
 179                blks_per_cluster = XFS_INODE_CLUSTER_SIZE(mp) /
 180                                   mp->m_sb.sb_blocksize;
 181                nbufs = length / blks_per_cluster;
 182                ninodes = blks_per_cluster * mp->m_sb.sb_inopblock;
 183        }
 184
 185        /*
 186         * Figure out what version number to use in the inodes we create.
 187         * If the superblock version has caught up to the one that supports
 188         * the new inode format, then use the new inode version.  Otherwise
 189         * use the old version so that old kernels will continue to be
 190         * able to use the file system.
 191         */
 192        if (xfs_sb_version_hasnlink(&mp->m_sb))
 193                version = 2;
 194        else
 195                version = 1;
 196
 197        for (j = 0; j < nbufs; j++) {
 198                /*
 199                 * Get the block.
 200                 */
 201                d = XFS_AGB_TO_DADDR(mp, agno, agbno + (j * blks_per_cluster));
 202                fbuf = xfs_trans_get_buf(tp, mp->m_ddev_targp, d,
 203                                         mp->m_bsize * blks_per_cluster,
 204                                         XBF_UNMAPPED);
 205                if (!fbuf)
 206                        return ENOMEM;
 207                /*
 208                 * Initialize all inodes in this buffer and then log them.
 209                 *
 210                 * XXX: It would be much better if we had just one transaction
 211                 *      to log a whole cluster of inodes instead of all the
 212                 *      individual transactions causing a lot of log traffic.
 213                 */
 214                fbuf->b_ops = &xfs_inode_buf_ops;
 215                xfs_buf_zero(fbuf, 0, ninodes << mp->m_sb.sb_inodelog);
 216                for (i = 0; i < ninodes; i++) {
 217                        int     ioffset = i << mp->m_sb.sb_inodelog;
 218                        uint    isize = sizeof(struct xfs_dinode);
 219
 220                        free = xfs_make_iptr(mp, fbuf, i);
 221                        free->di_magic = cpu_to_be16(XFS_DINODE_MAGIC);
 222                        free->di_version = version;
 223                        free->di_gen = cpu_to_be32(gen);
 224                        free->di_next_unlinked = cpu_to_be32(NULLAGINO);
 225                        xfs_trans_log_buf(tp, fbuf, ioffset, ioffset + isize - 1);
 226                }
 227                xfs_trans_inode_alloc_buf(tp, fbuf);
 228        }
 229        return 0;
 230}
 231
 232/*
 233 * Allocate new inodes in the allocation group specified by agbp.
 234 * Return 0 for success, else error code.
 235 */
 236STATIC int                              /* error code or 0 */
 237xfs_ialloc_ag_alloc(
 238        xfs_trans_t     *tp,            /* transaction pointer */
 239        xfs_buf_t       *agbp,          /* alloc group buffer */
 240        int             *alloc)
 241{
 242        xfs_agi_t       *agi;           /* allocation group header */
 243        xfs_alloc_arg_t args;           /* allocation argument structure */
 244        xfs_btree_cur_t *cur;           /* inode btree cursor */
 245        xfs_agnumber_t  agno;
 246        int             error;
 247        int             i;
 248        xfs_agino_t     newino;         /* new first inode's number */
 249        xfs_agino_t     newlen;         /* new number of inodes */
 250        xfs_agino_t     thisino;        /* current inode number, for loop */
 251        int             isaligned = 0;  /* inode allocation at stripe unit */
 252                                        /* boundary */
 253        struct xfs_perag *pag;
 254
 255        memset(&args, 0, sizeof(args));
 256        args.tp = tp;
 257        args.mp = tp->t_mountp;
 258
 259        /*
 260         * Locking will ensure that we don't have two callers in here
 261         * at one time.
 262         */
 263        newlen = XFS_IALLOC_INODES(args.mp);
 264        if (args.mp->m_maxicount &&
 265            args.mp->m_sb.sb_icount + newlen > args.mp->m_maxicount)
 266                return XFS_ERROR(ENOSPC);
 267        args.minlen = args.maxlen = XFS_IALLOC_BLOCKS(args.mp);
 268        /*
 269         * First try to allocate inodes contiguous with the last-allocated
 270         * chunk of inodes.  If the filesystem is striped, this will fill
 271         * an entire stripe unit with inodes.
 272         */
 273        agi = XFS_BUF_TO_AGI(agbp);
 274        newino = be32_to_cpu(agi->agi_newino);
 275        agno = be32_to_cpu(agi->agi_seqno);
 276        args.agbno = XFS_AGINO_TO_AGBNO(args.mp, newino) +
 277                        XFS_IALLOC_BLOCKS(args.mp);
 278        if (likely(newino != NULLAGINO &&
 279                  (args.agbno < be32_to_cpu(agi->agi_length)))) {
 280                args.fsbno = XFS_AGB_TO_FSB(args.mp, agno, args.agbno);
 281                args.type = XFS_ALLOCTYPE_THIS_BNO;
 282                args.mod = args.total = args.wasdel = args.isfl =
 283                        args.userdata = args.minalignslop = 0;
 284                args.prod = 1;
 285
 286                /*
 287                 * We need to take into account alignment here to ensure that
 288                 * we don't modify the free list if we fail to have an exact
 289                 * block. If we don't have an exact match, and every oher
 290                 * attempt allocation attempt fails, we'll end up cancelling
 291                 * a dirty transaction and shutting down.
 292                 *
 293                 * For an exact allocation, alignment must be 1,
 294                 * however we need to take cluster alignment into account when
 295                 * fixing up the freelist. Use the minalignslop field to
 296                 * indicate that extra blocks might be required for alignment,
 297                 * but not to use them in the actual exact allocation.
 298                 */
 299                args.alignment = 1;
 300                args.minalignslop = xfs_ialloc_cluster_alignment(&args) - 1;
 301
 302                /* Allow space for the inode btree to split. */
 303                args.minleft = args.mp->m_in_maxlevels - 1;
 304                if ((error = xfs_alloc_vextent(&args)))
 305                        return error;
 306        } else
 307                args.fsbno = NULLFSBLOCK;
 308
 309        if (unlikely(args.fsbno == NULLFSBLOCK)) {
 310                /*
 311                 * Set the alignment for the allocation.
 312                 * If stripe alignment is turned on then align at stripe unit
 313                 * boundary.
 314                 * If the cluster size is smaller than a filesystem block
 315                 * then we're doing I/O for inodes in filesystem block size
 316                 * pieces, so don't need alignment anyway.
 317                 */
 318                isaligned = 0;
 319                if (args.mp->m_sinoalign) {
 320                        ASSERT(!(args.mp->m_flags & XFS_MOUNT_NOALIGN));
 321                        args.alignment = args.mp->m_dalign;
 322                        isaligned = 1;
 323                } else
 324                        args.alignment = xfs_ialloc_cluster_alignment(&args);
 325                /*
 326                 * Need to figure out where to allocate the inode blocks.
 327                 * Ideally they should be spaced out through the a.g.
 328                 * For now, just allocate blocks up front.
 329                 */
 330                args.agbno = be32_to_cpu(agi->agi_root);
 331                args.fsbno = XFS_AGB_TO_FSB(args.mp, agno, args.agbno);
 332                /*
 333                 * Allocate a fixed-size extent of inodes.
 334                 */
 335                args.type = XFS_ALLOCTYPE_NEAR_BNO;
 336                args.mod = args.total = args.wasdel = args.isfl =
 337                        args.userdata = args.minalignslop = 0;
 338                args.prod = 1;
 339                /*
 340                 * Allow space for the inode btree to split.
 341                 */
 342                args.minleft = args.mp->m_in_maxlevels - 1;
 343                if ((error = xfs_alloc_vextent(&args)))
 344                        return error;
 345        }
 346
 347        /*
 348         * If stripe alignment is turned on, then try again with cluster
 349         * alignment.
 350         */
 351        if (isaligned && args.fsbno == NULLFSBLOCK) {
 352                args.type = XFS_ALLOCTYPE_NEAR_BNO;
 353                args.agbno = be32_to_cpu(agi->agi_root);
 354                args.fsbno = XFS_AGB_TO_FSB(args.mp, agno, args.agbno);
 355                args.alignment = xfs_ialloc_cluster_alignment(&args);
 356                if ((error = xfs_alloc_vextent(&args)))
 357                        return error;
 358        }
 359
 360        if (args.fsbno == NULLFSBLOCK) {
 361                *alloc = 0;
 362                return 0;
 363        }
 364        ASSERT(args.len == args.minlen);
 365
 366        /*
 367         * Stamp and write the inode buffers.
 368         *
 369         * Seed the new inode cluster with a random generation number. This
 370         * prevents short-term reuse of generation numbers if a chunk is
 371         * freed and then immediately reallocated. We use random numbers
 372         * rather than a linear progression to prevent the next generation
 373         * number from being easily guessable.
 374         */
 375        error = xfs_ialloc_inode_init(args.mp, tp, agno, args.agbno,
 376                        args.len, random32());
 377
 378        if (error)
 379                return error;
 380        /*
 381         * Convert the results.
 382         */
 383        newino = XFS_OFFBNO_TO_AGINO(args.mp, args.agbno, 0);
 384        be32_add_cpu(&agi->agi_count, newlen);
 385        be32_add_cpu(&agi->agi_freecount, newlen);
 386        pag = xfs_perag_get(args.mp, agno);
 387        pag->pagi_freecount += newlen;
 388        xfs_perag_put(pag);
 389        agi->agi_newino = cpu_to_be32(newino);
 390
 391        /*
 392         * Insert records describing the new inode chunk into the btree.
 393         */
 394        cur = xfs_inobt_init_cursor(args.mp, tp, agbp, agno);
 395        for (thisino = newino;
 396             thisino < newino + newlen;
 397             thisino += XFS_INODES_PER_CHUNK) {
 398                cur->bc_rec.i.ir_startino = thisino;
 399                cur->bc_rec.i.ir_freecount = XFS_INODES_PER_CHUNK;
 400                cur->bc_rec.i.ir_free = XFS_INOBT_ALL_FREE;
 401                error = xfs_btree_lookup(cur, XFS_LOOKUP_EQ, &i);
 402                if (error) {
 403                        xfs_btree_del_cursor(cur, XFS_BTREE_ERROR);
 404                        return error;
 405                }
 406                ASSERT(i == 0);
 407                error = xfs_btree_insert(cur, &i);
 408                if (error) {
 409                        xfs_btree_del_cursor(cur, XFS_BTREE_ERROR);
 410                        return error;
 411                }
 412                ASSERT(i == 1);
 413        }
 414        xfs_btree_del_cursor(cur, XFS_BTREE_NOERROR);
 415        /*
 416         * Log allocation group header fields
 417         */
 418        xfs_ialloc_log_agi(tp, agbp,
 419                XFS_AGI_COUNT | XFS_AGI_FREECOUNT | XFS_AGI_NEWINO);
 420        /*
 421         * Modify/log superblock values for inode count and inode free count.
 422         */
 423        xfs_trans_mod_sb(tp, XFS_TRANS_SB_ICOUNT, (long)newlen);
 424        xfs_trans_mod_sb(tp, XFS_TRANS_SB_IFREE, (long)newlen);
 425        *alloc = 1;
 426        return 0;
 427}
 428
 429STATIC xfs_agnumber_t
 430xfs_ialloc_next_ag(
 431        xfs_mount_t     *mp)
 432{
 433        xfs_agnumber_t  agno;
 434
 435        spin_lock(&mp->m_agirotor_lock);
 436        agno = mp->m_agirotor;
 437        if (++mp->m_agirotor >= mp->m_maxagi)
 438                mp->m_agirotor = 0;
 439        spin_unlock(&mp->m_agirotor_lock);
 440
 441        return agno;
 442}
 443
 444/*
 445 * Select an allocation group to look for a free inode in, based on the parent
 446 * inode and then mode.  Return the allocation group buffer.
 447 */
 448STATIC xfs_agnumber_t
 449xfs_ialloc_ag_select(
 450        xfs_trans_t     *tp,            /* transaction pointer */
 451        xfs_ino_t       parent,         /* parent directory inode number */
 452        umode_t         mode,           /* bits set to indicate file type */
 453        int             okalloc)        /* ok to allocate more space */
 454{
 455        xfs_agnumber_t  agcount;        /* number of ag's in the filesystem */
 456        xfs_agnumber_t  agno;           /* current ag number */
 457        int             flags;          /* alloc buffer locking flags */
 458        xfs_extlen_t    ineed;          /* blocks needed for inode allocation */
 459        xfs_extlen_t    longest = 0;    /* longest extent available */
 460        xfs_mount_t     *mp;            /* mount point structure */
 461        int             needspace;      /* file mode implies space allocated */
 462        xfs_perag_t     *pag;           /* per allocation group data */
 463        xfs_agnumber_t  pagno;          /* parent (starting) ag number */
 464        int             error;
 465
 466        /*
 467         * Files of these types need at least one block if length > 0
 468         * (and they won't fit in the inode, but that's hard to figure out).
 469         */
 470        needspace = S_ISDIR(mode) || S_ISREG(mode) || S_ISLNK(mode);
 471        mp = tp->t_mountp;
 472        agcount = mp->m_maxagi;
 473        if (S_ISDIR(mode))
 474                pagno = xfs_ialloc_next_ag(mp);
 475        else {
 476                pagno = XFS_INO_TO_AGNO(mp, parent);
 477                if (pagno >= agcount)
 478                        pagno = 0;
 479        }
 480
 481        ASSERT(pagno < agcount);
 482
 483        /*
 484         * Loop through allocation groups, looking for one with a little
 485         * free space in it.  Note we don't look for free inodes, exactly.
 486         * Instead, we include whether there is a need to allocate inodes
 487         * to mean that blocks must be allocated for them,
 488         * if none are currently free.
 489         */
 490        agno = pagno;
 491        flags = XFS_ALLOC_FLAG_TRYLOCK;
 492        for (;;) {
 493                pag = xfs_perag_get(mp, agno);
 494                if (!pag->pagi_inodeok) {
 495                        xfs_ialloc_next_ag(mp);
 496                        goto nextag;
 497                }
 498
 499                if (!pag->pagi_init) {
 500                        error = xfs_ialloc_pagi_init(mp, tp, agno);
 501                        if (error)
 502                                goto nextag;
 503                }
 504
 505                if (pag->pagi_freecount) {
 506                        xfs_perag_put(pag);
 507                        return agno;
 508                }
 509
 510                if (!okalloc)
 511                        goto nextag;
 512
 513                if (!pag->pagf_init) {
 514                        error = xfs_alloc_pagf_init(mp, tp, agno, flags);
 515                        if (error)
 516                                goto nextag;
 517                }
 518
 519                /*
 520                 * Is there enough free space for the file plus a block of
 521                 * inodes? (if we need to allocate some)?
 522                 */
 523                ineed = XFS_IALLOC_BLOCKS(mp);
 524                longest = pag->pagf_longest;
 525                if (!longest)
 526                        longest = pag->pagf_flcount > 0;
 527
 528                if (pag->pagf_freeblks >= needspace + ineed &&
 529                    longest >= ineed) {
 530                        xfs_perag_put(pag);
 531                        return agno;
 532                }
 533nextag:
 534                xfs_perag_put(pag);
 535                /*
 536                 * No point in iterating over the rest, if we're shutting
 537                 * down.
 538                 */
 539                if (XFS_FORCED_SHUTDOWN(mp))
 540                        return NULLAGNUMBER;
 541                agno++;
 542                if (agno >= agcount)
 543                        agno = 0;
 544                if (agno == pagno) {
 545                        if (flags == 0)
 546                                return NULLAGNUMBER;
 547                        flags = 0;
 548                }
 549        }
 550}
 551
 552/*
 553 * Try to retrieve the next record to the left/right from the current one.
 554 */
 555STATIC int
 556xfs_ialloc_next_rec(
 557        struct xfs_btree_cur    *cur,
 558        xfs_inobt_rec_incore_t  *rec,
 559        int                     *done,
 560        int                     left)
 561{
 562        int                     error;
 563        int                     i;
 564
 565        if (left)
 566                error = xfs_btree_decrement(cur, 0, &i);
 567        else
 568                error = xfs_btree_increment(cur, 0, &i);
 569
 570        if (error)
 571                return error;
 572        *done = !i;
 573        if (i) {
 574                error = xfs_inobt_get_rec(cur, rec, &i);
 575                if (error)
 576                        return error;
 577                XFS_WANT_CORRUPTED_RETURN(i == 1);
 578        }
 579
 580        return 0;
 581}
 582
 583STATIC int
 584xfs_ialloc_get_rec(
 585        struct xfs_btree_cur    *cur,
 586        xfs_agino_t             agino,
 587        xfs_inobt_rec_incore_t  *rec,
 588        int                     *done,
 589        int                     left)
 590{
 591        int                     error;
 592        int                     i;
 593
 594        error = xfs_inobt_lookup(cur, agino, XFS_LOOKUP_EQ, &i);
 595        if (error)
 596                return error;
 597        *done = !i;
 598        if (i) {
 599                error = xfs_inobt_get_rec(cur, rec, &i);
 600                if (error)
 601                        return error;
 602                XFS_WANT_CORRUPTED_RETURN(i == 1);
 603        }
 604
 605        return 0;
 606}
 607
 608/*
 609 * Allocate an inode.
 610 *
 611 * The caller selected an AG for us, and made sure that free inodes are
 612 * available.
 613 */
 614STATIC int
 615xfs_dialloc_ag(
 616        struct xfs_trans        *tp,
 617        struct xfs_buf          *agbp,
 618        xfs_ino_t               parent,
 619        xfs_ino_t               *inop)
 620{
 621        struct xfs_mount        *mp = tp->t_mountp;
 622        struct xfs_agi          *agi = XFS_BUF_TO_AGI(agbp);
 623        xfs_agnumber_t          agno = be32_to_cpu(agi->agi_seqno);
 624        xfs_agnumber_t          pagno = XFS_INO_TO_AGNO(mp, parent);
 625        xfs_agino_t             pagino = XFS_INO_TO_AGINO(mp, parent);
 626        struct xfs_perag        *pag;
 627        struct xfs_btree_cur    *cur, *tcur;
 628        struct xfs_inobt_rec_incore rec, trec;
 629        xfs_ino_t               ino;
 630        int                     error;
 631        int                     offset;
 632        int                     i, j;
 633
 634        pag = xfs_perag_get(mp, agno);
 635
 636        ASSERT(pag->pagi_init);
 637        ASSERT(pag->pagi_inodeok);
 638        ASSERT(pag->pagi_freecount > 0);
 639
 640 restart_pagno:
 641        cur = xfs_inobt_init_cursor(mp, tp, agbp, agno);
 642        /*
 643         * If pagino is 0 (this is the root inode allocation) use newino.
 644         * This must work because we've just allocated some.
 645         */
 646        if (!pagino)
 647                pagino = be32_to_cpu(agi->agi_newino);
 648
 649        error = xfs_check_agi_freecount(cur, agi);
 650        if (error)
 651                goto error0;
 652
 653        /*
 654         * If in the same AG as the parent, try to get near the parent.
 655         */
 656        if (pagno == agno) {
 657                int             doneleft;       /* done, to the left */
 658                int             doneright;      /* done, to the right */
 659                int             searchdistance = 10;
 660
 661                error = xfs_inobt_lookup(cur, pagino, XFS_LOOKUP_LE, &i);
 662                if (error)
 663                        goto error0;
 664                XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
 665
 666                error = xfs_inobt_get_rec(cur, &rec, &j);
 667                if (error)
 668                        goto error0;
 669                XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
 670
 671                if (rec.ir_freecount > 0) {
 672                        /*
 673                         * Found a free inode in the same chunk
 674                         * as the parent, done.
 675                         */
 676                        goto alloc_inode;
 677                }
 678
 679
 680                /*
 681                 * In the same AG as parent, but parent's chunk is full.
 682                 */
 683
 684                /* duplicate the cursor, search left & right simultaneously */
 685                error = xfs_btree_dup_cursor(cur, &tcur);
 686                if (error)
 687                        goto error0;
 688
 689                /*
 690                 * Skip to last blocks looked up if same parent inode.
 691                 */
 692                if (pagino != NULLAGINO &&
 693                    pag->pagl_pagino == pagino &&
 694                    pag->pagl_leftrec != NULLAGINO &&
 695                    pag->pagl_rightrec != NULLAGINO) {
 696                        error = xfs_ialloc_get_rec(tcur, pag->pagl_leftrec,
 697                                                   &trec, &doneleft, 1);
 698                        if (error)
 699                                goto error1;
 700
 701                        error = xfs_ialloc_get_rec(cur, pag->pagl_rightrec,
 702                                                   &rec, &doneright, 0);
 703                        if (error)
 704                                goto error1;
 705                } else {
 706                        /* search left with tcur, back up 1 record */
 707                        error = xfs_ialloc_next_rec(tcur, &trec, &doneleft, 1);
 708                        if (error)
 709                                goto error1;
 710
 711                        /* search right with cur, go forward 1 record. */
 712                        error = xfs_ialloc_next_rec(cur, &rec, &doneright, 0);
 713                        if (error)
 714                                goto error1;
 715                }
 716
 717                /*
 718                 * Loop until we find an inode chunk with a free inode.
 719                 */
 720                while (!doneleft || !doneright) {
 721                        int     useleft;  /* using left inode chunk this time */
 722
 723                        if (!--searchdistance) {
 724                                /*
 725                                 * Not in range - save last search
 726                                 * location and allocate a new inode
 727                                 */
 728                                xfs_btree_del_cursor(tcur, XFS_BTREE_NOERROR);
 729                                pag->pagl_leftrec = trec.ir_startino;
 730                                pag->pagl_rightrec = rec.ir_startino;
 731                                pag->pagl_pagino = pagino;
 732                                goto newino;
 733                        }
 734
 735                        /* figure out the closer block if both are valid. */
 736                        if (!doneleft && !doneright) {
 737                                useleft = pagino -
 738                                 (trec.ir_startino + XFS_INODES_PER_CHUNK - 1) <
 739                                  rec.ir_startino - pagino;
 740                        } else {
 741                                useleft = !doneleft;
 742                        }
 743
 744                        /* free inodes to the left? */
 745                        if (useleft && trec.ir_freecount) {
 746                                rec = trec;
 747                                xfs_btree_del_cursor(cur, XFS_BTREE_NOERROR);
 748                                cur = tcur;
 749
 750                                pag->pagl_leftrec = trec.ir_startino;
 751                                pag->pagl_rightrec = rec.ir_startino;
 752                                pag->pagl_pagino = pagino;
 753                                goto alloc_inode;
 754                        }
 755
 756                        /* free inodes to the right? */
 757                        if (!useleft && rec.ir_freecount) {
 758                                xfs_btree_del_cursor(tcur, XFS_BTREE_NOERROR);
 759
 760                                pag->pagl_leftrec = trec.ir_startino;
 761                                pag->pagl_rightrec = rec.ir_startino;
 762                                pag->pagl_pagino = pagino;
 763                                goto alloc_inode;
 764                        }
 765
 766                        /* get next record to check */
 767                        if (useleft) {
 768                                error = xfs_ialloc_next_rec(tcur, &trec,
 769                                                                 &doneleft, 1);
 770                        } else {
 771                                error = xfs_ialloc_next_rec(cur, &rec,
 772                                                                 &doneright, 0);
 773                        }
 774                        if (error)
 775                                goto error1;
 776                }
 777
 778                /*
 779                 * We've reached the end of the btree. because
 780                 * we are only searching a small chunk of the
 781                 * btree each search, there is obviously free
 782                 * inodes closer to the parent inode than we
 783                 * are now. restart the search again.
 784                 */
 785                pag->pagl_pagino = NULLAGINO;
 786                pag->pagl_leftrec = NULLAGINO;
 787                pag->pagl_rightrec = NULLAGINO;
 788                xfs_btree_del_cursor(tcur, XFS_BTREE_NOERROR);
 789                xfs_btree_del_cursor(cur, XFS_BTREE_NOERROR);
 790                goto restart_pagno;
 791        }
 792
 793        /*
 794         * In a different AG from the parent.
 795         * See if the most recently allocated block has any free.
 796         */
 797newino:
 798        if (agi->agi_newino != cpu_to_be32(NULLAGINO)) {
 799                error = xfs_inobt_lookup(cur, be32_to_cpu(agi->agi_newino),
 800                                         XFS_LOOKUP_EQ, &i);
 801                if (error)
 802                        goto error0;
 803
 804                if (i == 1) {
 805                        error = xfs_inobt_get_rec(cur, &rec, &j);
 806                        if (error)
 807                                goto error0;
 808
 809                        if (j == 1 && rec.ir_freecount > 0) {
 810                                /*
 811                                 * The last chunk allocated in the group
 812                                 * still has a free inode.
 813                                 */
 814                                goto alloc_inode;
 815                        }
 816                }
 817        }
 818
 819        /*
 820         * None left in the last group, search the whole AG
 821         */
 822        error = xfs_inobt_lookup(cur, 0, XFS_LOOKUP_GE, &i);
 823        if (error)
 824                goto error0;
 825        XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
 826
 827        for (;;) {
 828                error = xfs_inobt_get_rec(cur, &rec, &i);
 829                if (error)
 830                        goto error0;
 831                XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
 832                if (rec.ir_freecount > 0)
 833                        break;
 834                error = xfs_btree_increment(cur, 0, &i);
 835                if (error)
 836                        goto error0;
 837                XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
 838        }
 839
 840alloc_inode:
 841        offset = xfs_lowbit64(rec.ir_free);
 842        ASSERT(offset >= 0);
 843        ASSERT(offset < XFS_INODES_PER_CHUNK);
 844        ASSERT((XFS_AGINO_TO_OFFSET(mp, rec.ir_startino) %
 845                                   XFS_INODES_PER_CHUNK) == 0);
 846        ino = XFS_AGINO_TO_INO(mp, agno, rec.ir_startino + offset);
 847        rec.ir_free &= ~XFS_INOBT_MASK(offset);
 848        rec.ir_freecount--;
 849        error = xfs_inobt_update(cur, &rec);
 850        if (error)
 851                goto error0;
 852        be32_add_cpu(&agi->agi_freecount, -1);
 853        xfs_ialloc_log_agi(tp, agbp, XFS_AGI_FREECOUNT);
 854        pag->pagi_freecount--;
 855
 856        error = xfs_check_agi_freecount(cur, agi);
 857        if (error)
 858                goto error0;
 859
 860        xfs_btree_del_cursor(cur, XFS_BTREE_NOERROR);
 861        xfs_trans_mod_sb(tp, XFS_TRANS_SB_IFREE, -1);
 862        xfs_perag_put(pag);
 863        *inop = ino;
 864        return 0;
 865error1:
 866        xfs_btree_del_cursor(tcur, XFS_BTREE_ERROR);
 867error0:
 868        xfs_btree_del_cursor(cur, XFS_BTREE_ERROR);
 869        xfs_perag_put(pag);
 870        return error;
 871}
 872
 873/*
 874 * Allocate an inode on disk.
 875 *
 876 * Mode is used to tell whether the new inode will need space, and whether it
 877 * is a directory.
 878 *
 879 * This function is designed to be called twice if it has to do an allocation
 880 * to make more free inodes.  On the first call, *IO_agbp should be set to NULL.
 881 * If an inode is available without having to performn an allocation, an inode
 882 * number is returned.  In this case, *IO_agbp is set to NULL.  If an allocation
 883 * needs to be done, xfs_dialloc returns the current AGI buffer in *IO_agbp.
 884 * The caller should then commit the current transaction, allocate a
 885 * new transaction, and call xfs_dialloc() again, passing in the previous value
 886 * of *IO_agbp.  IO_agbp should be held across the transactions. Since the AGI
 887 * buffer is locked across the two calls, the second call is guaranteed to have
 888 * a free inode available.
 889 *
 890 * Once we successfully pick an inode its number is returned and the on-disk
 891 * data structures are updated.  The inode itself is not read in, since doing so
 892 * would break ordering constraints with xfs_reclaim.
 893 */
 894int
 895xfs_dialloc(
 896        struct xfs_trans        *tp,
 897        xfs_ino_t               parent,
 898        umode_t                 mode,
 899        int                     okalloc,
 900        struct xfs_buf          **IO_agbp,
 901        xfs_ino_t               *inop)
 902{
 903        struct xfs_mount        *mp = tp->t_mountp;
 904        struct xfs_buf          *agbp;
 905        xfs_agnumber_t          agno;
 906        int                     error;
 907        int                     ialloced;
 908        int                     noroom = 0;
 909        xfs_agnumber_t          start_agno;
 910        struct xfs_perag        *pag;
 911
 912        if (*IO_agbp) {
 913                /*
 914                 * If the caller passes in a pointer to the AGI buffer,
 915                 * continue where we left off before.  In this case, we
 916                 * know that the allocation group has free inodes.
 917                 */
 918                agbp = *IO_agbp;
 919                goto out_alloc;
 920        }
 921
 922        /*
 923         * We do not have an agbp, so select an initial allocation
 924         * group for inode allocation.
 925         */
 926        start_agno = xfs_ialloc_ag_select(tp, parent, mode, okalloc);
 927        if (start_agno == NULLAGNUMBER) {
 928                *inop = NULLFSINO;
 929                return 0;
 930        }
 931
 932        /*
 933         * If we have already hit the ceiling of inode blocks then clear
 934         * okalloc so we scan all available agi structures for a free
 935         * inode.
 936         */
 937        if (mp->m_maxicount &&
 938            mp->m_sb.sb_icount + XFS_IALLOC_INODES(mp) > mp->m_maxicount) {
 939                noroom = 1;
 940                okalloc = 0;
 941        }
 942
 943        /*
 944         * Loop until we find an allocation group that either has free inodes
 945         * or in which we can allocate some inodes.  Iterate through the
 946         * allocation groups upward, wrapping at the end.
 947         */
 948        agno = start_agno;
 949        for (;;) {
 950                pag = xfs_perag_get(mp, agno);
 951                if (!pag->pagi_inodeok) {
 952                        xfs_ialloc_next_ag(mp);
 953                        goto nextag;
 954                }
 955
 956                if (!pag->pagi_init) {
 957                        error = xfs_ialloc_pagi_init(mp, tp, agno);
 958                        if (error)
 959                                goto out_error;
 960                }
 961
 962                /*
 963                 * Do a first racy fast path check if this AG is usable.
 964                 */
 965                if (!pag->pagi_freecount && !okalloc)
 966                        goto nextag;
 967
 968                /*
 969                 * Then read in the AGI buffer and recheck with the AGI buffer
 970                 * lock held.
 971                 */
 972                error = xfs_ialloc_read_agi(mp, tp, agno, &agbp);
 973                if (error)
 974                        goto out_error;
 975
 976                if (pag->pagi_freecount) {
 977                        xfs_perag_put(pag);
 978                        goto out_alloc;
 979                }
 980
 981                if (!okalloc)
 982                        goto nextag_relse_buffer;
 983
 984
 985                error = xfs_ialloc_ag_alloc(tp, agbp, &ialloced);
 986                if (error) {
 987                        xfs_trans_brelse(tp, agbp);
 988
 989                        if (error != ENOSPC)
 990                                goto out_error;
 991
 992                        xfs_perag_put(pag);
 993                        *inop = NULLFSINO;
 994                        return 0;
 995                }
 996
 997                if (ialloced) {
 998                        /*
 999                         * We successfully allocated some inodes, return
1000                         * the current context to the caller so that it
1001                         * can commit the current transaction and call
1002                         * us again where we left off.
1003                         */
1004                        ASSERT(pag->pagi_freecount > 0);
1005                        xfs_perag_put(pag);
1006
1007                        *IO_agbp = agbp;
1008                        *inop = NULLFSINO;
1009                        return 0;
1010                }
1011
1012nextag_relse_buffer:
1013                xfs_trans_brelse(tp, agbp);
1014nextag:
1015                xfs_perag_put(pag);
1016                if (++agno == mp->m_sb.sb_agcount)
1017                        agno = 0;
1018                if (agno == start_agno) {
1019                        *inop = NULLFSINO;
1020                        return noroom ? ENOSPC : 0;
1021                }
1022        }
1023
1024out_alloc:
1025        *IO_agbp = NULL;
1026        return xfs_dialloc_ag(tp, agbp, parent, inop);
1027out_error:
1028        xfs_perag_put(pag);
1029        return XFS_ERROR(error);
1030}
1031
1032/*
1033 * Free disk inode.  Carefully avoids touching the incore inode, all
1034 * manipulations incore are the caller's responsibility.
1035 * The on-disk inode is not changed by this operation, only the
1036 * btree (free inode mask) is changed.
1037 */
1038int
1039xfs_difree(
1040        xfs_trans_t     *tp,            /* transaction pointer */
1041        xfs_ino_t       inode,          /* inode to be freed */
1042        xfs_bmap_free_t *flist,         /* extents to free */
1043        int             *delete,        /* set if inode cluster was deleted */
1044        xfs_ino_t       *first_ino)     /* first inode in deleted cluster */
1045{
1046        /* REFERENCED */
1047        xfs_agblock_t   agbno;  /* block number containing inode */
1048        xfs_buf_t       *agbp;  /* buffer containing allocation group header */
1049        xfs_agino_t     agino;  /* inode number relative to allocation group */
1050        xfs_agnumber_t  agno;   /* allocation group number */
1051        xfs_agi_t       *agi;   /* allocation group header */
1052        xfs_btree_cur_t *cur;   /* inode btree cursor */
1053        int             error;  /* error return value */
1054        int             i;      /* result code */
1055        int             ilen;   /* inodes in an inode cluster */
1056        xfs_mount_t     *mp;    /* mount structure for filesystem */
1057        int             off;    /* offset of inode in inode chunk */
1058        xfs_inobt_rec_incore_t rec;     /* btree record */
1059        struct xfs_perag *pag;
1060
1061        mp = tp->t_mountp;
1062
1063        /*
1064         * Break up inode number into its components.
1065         */
1066        agno = XFS_INO_TO_AGNO(mp, inode);
1067        if (agno >= mp->m_sb.sb_agcount)  {
1068                xfs_warn(mp, "%s: agno >= mp->m_sb.sb_agcount (%d >= %d).",
1069                        __func__, agno, mp->m_sb.sb_agcount);
1070                ASSERT(0);
1071                return XFS_ERROR(EINVAL);
1072        }
1073        agino = XFS_INO_TO_AGINO(mp, inode);
1074        if (inode != XFS_AGINO_TO_INO(mp, agno, agino))  {
1075                xfs_warn(mp, "%s: inode != XFS_AGINO_TO_INO() (%llu != %llu).",
1076                        __func__, (unsigned long long)inode,
1077                        (unsigned long long)XFS_AGINO_TO_INO(mp, agno, agino));
1078                ASSERT(0);
1079                return XFS_ERROR(EINVAL);
1080        }
1081        agbno = XFS_AGINO_TO_AGBNO(mp, agino);
1082        if (agbno >= mp->m_sb.sb_agblocks)  {
1083                xfs_warn(mp, "%s: agbno >= mp->m_sb.sb_agblocks (%d >= %d).",
1084                        __func__, agbno, mp->m_sb.sb_agblocks);
1085                ASSERT(0);
1086                return XFS_ERROR(EINVAL);
1087        }
1088        /*
1089         * Get the allocation group header.
1090         */
1091        error = xfs_ialloc_read_agi(mp, tp, agno, &agbp);
1092        if (error) {
1093                xfs_warn(mp, "%s: xfs_ialloc_read_agi() returned error %d.",
1094                        __func__, error);
1095                return error;
1096        }
1097        agi = XFS_BUF_TO_AGI(agbp);
1098        ASSERT(agi->agi_magicnum == cpu_to_be32(XFS_AGI_MAGIC));
1099        ASSERT(agbno < be32_to_cpu(agi->agi_length));
1100        /*
1101         * Initialize the cursor.
1102         */
1103        cur = xfs_inobt_init_cursor(mp, tp, agbp, agno);
1104
1105        error = xfs_check_agi_freecount(cur, agi);
1106        if (error)
1107                goto error0;
1108
1109        /*
1110         * Look for the entry describing this inode.
1111         */
1112        if ((error = xfs_inobt_lookup(cur, agino, XFS_LOOKUP_LE, &i))) {
1113                xfs_warn(mp, "%s: xfs_inobt_lookup() returned error %d.",
1114                        __func__, error);
1115                goto error0;
1116        }
1117        XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
1118        error = xfs_inobt_get_rec(cur, &rec, &i);
1119        if (error) {
1120                xfs_warn(mp, "%s: xfs_inobt_get_rec() returned error %d.",
1121                        __func__, error);
1122                goto error0;
1123        }
1124        XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
1125        /*
1126         * Get the offset in the inode chunk.
1127         */
1128        off = agino - rec.ir_startino;
1129        ASSERT(off >= 0 && off < XFS_INODES_PER_CHUNK);
1130        ASSERT(!(rec.ir_free & XFS_INOBT_MASK(off)));
1131        /*
1132         * Mark the inode free & increment the count.
1133         */
1134        rec.ir_free |= XFS_INOBT_MASK(off);
1135        rec.ir_freecount++;
1136
1137        /*
1138         * When an inode cluster is free, it becomes eligible for removal
1139         */
1140        if (!(mp->m_flags & XFS_MOUNT_IKEEP) &&
1141            (rec.ir_freecount == XFS_IALLOC_INODES(mp))) {
1142
1143                *delete = 1;
1144                *first_ino = XFS_AGINO_TO_INO(mp, agno, rec.ir_startino);
1145
1146                /*
1147                 * Remove the inode cluster from the AGI B+Tree, adjust the
1148                 * AGI and Superblock inode counts, and mark the disk space
1149                 * to be freed when the transaction is committed.
1150                 */
1151                ilen = XFS_IALLOC_INODES(mp);
1152                be32_add_cpu(&agi->agi_count, -ilen);
1153                be32_add_cpu(&agi->agi_freecount, -(ilen - 1));
1154                xfs_ialloc_log_agi(tp, agbp, XFS_AGI_COUNT | XFS_AGI_FREECOUNT);
1155                pag = xfs_perag_get(mp, agno);
1156                pag->pagi_freecount -= ilen - 1;
1157                xfs_perag_put(pag);
1158                xfs_trans_mod_sb(tp, XFS_TRANS_SB_ICOUNT, -ilen);
1159                xfs_trans_mod_sb(tp, XFS_TRANS_SB_IFREE, -(ilen - 1));
1160
1161                if ((error = xfs_btree_delete(cur, &i))) {
1162                        xfs_warn(mp, "%s: xfs_btree_delete returned error %d.",
1163                                __func__, error);
1164                        goto error0;
1165                }
1166
1167                xfs_bmap_add_free(XFS_AGB_TO_FSB(mp,
1168                                agno, XFS_INO_TO_AGBNO(mp,rec.ir_startino)),
1169                                XFS_IALLOC_BLOCKS(mp), flist, mp);
1170        } else {
1171                *delete = 0;
1172
1173                error = xfs_inobt_update(cur, &rec);
1174                if (error) {
1175                        xfs_warn(mp, "%s: xfs_inobt_update returned error %d.",
1176                                __func__, error);
1177                        goto error0;
1178                }
1179
1180                /* 
1181                 * Change the inode free counts and log the ag/sb changes.
1182                 */
1183                be32_add_cpu(&agi->agi_freecount, 1);
1184                xfs_ialloc_log_agi(tp, agbp, XFS_AGI_FREECOUNT);
1185                pag = xfs_perag_get(mp, agno);
1186                pag->pagi_freecount++;
1187                xfs_perag_put(pag);
1188                xfs_trans_mod_sb(tp, XFS_TRANS_SB_IFREE, 1);
1189        }
1190
1191        error = xfs_check_agi_freecount(cur, agi);
1192        if (error)
1193                goto error0;
1194
1195        xfs_btree_del_cursor(cur, XFS_BTREE_NOERROR);
1196        return 0;
1197
1198error0:
1199        xfs_btree_del_cursor(cur, XFS_BTREE_ERROR);
1200        return error;
1201}
1202
1203STATIC int
1204xfs_imap_lookup(
1205        struct xfs_mount        *mp,
1206        struct xfs_trans        *tp,
1207        xfs_agnumber_t          agno,
1208        xfs_agino_t             agino,
1209        xfs_agblock_t           agbno,
1210        xfs_agblock_t           *chunk_agbno,
1211        xfs_agblock_t           *offset_agbno,
1212        int                     flags)
1213{
1214        struct xfs_inobt_rec_incore rec;
1215        struct xfs_btree_cur    *cur;
1216        struct xfs_buf          *agbp;
1217        int                     error;
1218        int                     i;
1219
1220        error = xfs_ialloc_read_agi(mp, tp, agno, &agbp);
1221        if (error) {
1222                xfs_alert(mp,
1223                        "%s: xfs_ialloc_read_agi() returned error %d, agno %d",
1224                        __func__, error, agno);
1225                return error;
1226        }
1227
1228        /*
1229         * Lookup the inode record for the given agino. If the record cannot be
1230         * found, then it's an invalid inode number and we should abort. Once
1231         * we have a record, we need to ensure it contains the inode number
1232         * we are looking up.
1233         */
1234        cur = xfs_inobt_init_cursor(mp, tp, agbp, agno);
1235        error = xfs_inobt_lookup(cur, agino, XFS_LOOKUP_LE, &i);
1236        if (!error) {
1237                if (i)
1238                        error = xfs_inobt_get_rec(cur, &rec, &i);
1239                if (!error && i == 0)
1240                        error = EINVAL;
1241        }
1242
1243        xfs_trans_brelse(tp, agbp);
1244        xfs_btree_del_cursor(cur, XFS_BTREE_NOERROR);
1245        if (error)
1246                return error;
1247
1248        /* check that the returned record contains the required inode */
1249        if (rec.ir_startino > agino ||
1250            rec.ir_startino + XFS_IALLOC_INODES(mp) <= agino)
1251                return EINVAL;
1252
1253        /* for untrusted inodes check it is allocated first */
1254        if ((flags & XFS_IGET_UNTRUSTED) &&
1255            (rec.ir_free & XFS_INOBT_MASK(agino - rec.ir_startino)))
1256                return EINVAL;
1257
1258        *chunk_agbno = XFS_AGINO_TO_AGBNO(mp, rec.ir_startino);
1259        *offset_agbno = agbno - *chunk_agbno;
1260        return 0;
1261}
1262
1263/*
1264 * Return the location of the inode in imap, for mapping it into a buffer.
1265 */
1266int
1267xfs_imap(
1268        xfs_mount_t      *mp,   /* file system mount structure */
1269        xfs_trans_t      *tp,   /* transaction pointer */
1270        xfs_ino_t       ino,    /* inode to locate */
1271        struct xfs_imap *imap,  /* location map structure */
1272        uint            flags)  /* flags for inode btree lookup */
1273{
1274        xfs_agblock_t   agbno;  /* block number of inode in the alloc group */
1275        xfs_agino_t     agino;  /* inode number within alloc group */
1276        xfs_agnumber_t  agno;   /* allocation group number */
1277        int             blks_per_cluster; /* num blocks per inode cluster */
1278        xfs_agblock_t   chunk_agbno;    /* first block in inode chunk */
1279        xfs_agblock_t   cluster_agbno;  /* first block in inode cluster */
1280        int             error;  /* error code */
1281        int             offset; /* index of inode in its buffer */
1282        int             offset_agbno;   /* blks from chunk start to inode */
1283
1284        ASSERT(ino != NULLFSINO);
1285
1286        /*
1287         * Split up the inode number into its parts.
1288         */
1289        agno = XFS_INO_TO_AGNO(mp, ino);
1290        agino = XFS_INO_TO_AGINO(mp, ino);
1291        agbno = XFS_AGINO_TO_AGBNO(mp, agino);
1292        if (agno >= mp->m_sb.sb_agcount || agbno >= mp->m_sb.sb_agblocks ||
1293            ino != XFS_AGINO_TO_INO(mp, agno, agino)) {
1294#ifdef DEBUG
1295                /*
1296                 * Don't output diagnostic information for untrusted inodes
1297                 * as they can be invalid without implying corruption.
1298                 */
1299                if (flags & XFS_IGET_UNTRUSTED)
1300                        return XFS_ERROR(EINVAL);
1301                if (agno >= mp->m_sb.sb_agcount) {
1302                        xfs_alert(mp,
1303                                "%s: agno (%d) >= mp->m_sb.sb_agcount (%d)",
1304                                __func__, agno, mp->m_sb.sb_agcount);
1305                }
1306                if (agbno >= mp->m_sb.sb_agblocks) {
1307                        xfs_alert(mp,
1308                "%s: agbno (0x%llx) >= mp->m_sb.sb_agblocks (0x%lx)",
1309                                __func__, (unsigned long long)agbno,
1310                                (unsigned long)mp->m_sb.sb_agblocks);
1311                }
1312                if (ino != XFS_AGINO_TO_INO(mp, agno, agino)) {
1313                        xfs_alert(mp,
1314                "%s: ino (0x%llx) != XFS_AGINO_TO_INO() (0x%llx)",
1315                                __func__, ino,
1316                                XFS_AGINO_TO_INO(mp, agno, agino));
1317                }
1318                xfs_stack_trace();
1319#endif /* DEBUG */
1320                return XFS_ERROR(EINVAL);
1321        }
1322
1323        blks_per_cluster = XFS_INODE_CLUSTER_SIZE(mp) >> mp->m_sb.sb_blocklog;
1324
1325        /*
1326         * For bulkstat and handle lookups, we have an untrusted inode number
1327         * that we have to verify is valid. We cannot do this just by reading
1328         * the inode buffer as it may have been unlinked and removed leaving
1329         * inodes in stale state on disk. Hence we have to do a btree lookup
1330         * in all cases where an untrusted inode number is passed.
1331         */
1332        if (flags & XFS_IGET_UNTRUSTED) {
1333                error = xfs_imap_lookup(mp, tp, agno, agino, agbno,
1334                                        &chunk_agbno, &offset_agbno, flags);
1335                if (error)
1336                        return error;
1337                goto out_map;
1338        }
1339
1340        /*
1341         * If the inode cluster size is the same as the blocksize or
1342         * smaller we get to the buffer by simple arithmetics.
1343         */
1344        if (XFS_INODE_CLUSTER_SIZE(mp) <= mp->m_sb.sb_blocksize) {
1345                offset = XFS_INO_TO_OFFSET(mp, ino);
1346                ASSERT(offset < mp->m_sb.sb_inopblock);
1347
1348                imap->im_blkno = XFS_AGB_TO_DADDR(mp, agno, agbno);
1349                imap->im_len = XFS_FSB_TO_BB(mp, 1);
1350                imap->im_boffset = (ushort)(offset << mp->m_sb.sb_inodelog);
1351                return 0;
1352        }
1353
1354        /*
1355         * If the inode chunks are aligned then use simple maths to
1356         * find the location. Otherwise we have to do a btree
1357         * lookup to find the location.
1358         */
1359        if (mp->m_inoalign_mask) {
1360                offset_agbno = agbno & mp->m_inoalign_mask;
1361                chunk_agbno = agbno - offset_agbno;
1362        } else {
1363                error = xfs_imap_lookup(mp, tp, agno, agino, agbno,
1364                                        &chunk_agbno, &offset_agbno, flags);
1365                if (error)
1366                        return error;
1367        }
1368
1369out_map:
1370        ASSERT(agbno >= chunk_agbno);
1371        cluster_agbno = chunk_agbno +
1372                ((offset_agbno / blks_per_cluster) * blks_per_cluster);
1373        offset = ((agbno - cluster_agbno) * mp->m_sb.sb_inopblock) +
1374                XFS_INO_TO_OFFSET(mp, ino);
1375
1376        imap->im_blkno = XFS_AGB_TO_DADDR(mp, agno, cluster_agbno);
1377        imap->im_len = XFS_FSB_TO_BB(mp, blks_per_cluster);
1378        imap->im_boffset = (ushort)(offset << mp->m_sb.sb_inodelog);
1379
1380        /*
1381         * If the inode number maps to a block outside the bounds
1382         * of the file system then return NULL rather than calling
1383         * read_buf and panicing when we get an error from the
1384         * driver.
1385         */
1386        if ((imap->im_blkno + imap->im_len) >
1387            XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks)) {
1388                xfs_alert(mp,
1389        "%s: (im_blkno (0x%llx) + im_len (0x%llx)) > sb_dblocks (0x%llx)",
1390                        __func__, (unsigned long long) imap->im_blkno,
1391                        (unsigned long long) imap->im_len,
1392                        XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks));
1393                return XFS_ERROR(EINVAL);
1394        }
1395        return 0;
1396}
1397
1398/*
1399 * Compute and fill in value of m_in_maxlevels.
1400 */
1401void
1402xfs_ialloc_compute_maxlevels(
1403        xfs_mount_t     *mp)            /* file system mount structure */
1404{
1405        int             level;
1406        uint            maxblocks;
1407        uint            maxleafents;
1408        int             minleafrecs;
1409        int             minnoderecs;
1410
1411        maxleafents = (1LL << XFS_INO_AGINO_BITS(mp)) >>
1412                XFS_INODES_PER_CHUNK_LOG;
1413        minleafrecs = mp->m_alloc_mnr[0];
1414        minnoderecs = mp->m_alloc_mnr[1];
1415        maxblocks = (maxleafents + minleafrecs - 1) / minleafrecs;
1416        for (level = 1; maxblocks > 1; level++)
1417                maxblocks = (maxblocks + minnoderecs - 1) / minnoderecs;
1418        mp->m_in_maxlevels = level;
1419}
1420
1421/*
1422 * Log specified fields for the ag hdr (inode section)
1423 */
1424void
1425xfs_ialloc_log_agi(
1426        xfs_trans_t     *tp,            /* transaction pointer */
1427        xfs_buf_t       *bp,            /* allocation group header buffer */
1428        int             fields)         /* bitmask of fields to log */
1429{
1430        int                     first;          /* first byte number */
1431        int                     last;           /* last byte number */
1432        static const short      offsets[] = {   /* field starting offsets */
1433                                        /* keep in sync with bit definitions */
1434                offsetof(xfs_agi_t, agi_magicnum),
1435                offsetof(xfs_agi_t, agi_versionnum),
1436                offsetof(xfs_agi_t, agi_seqno),
1437                offsetof(xfs_agi_t, agi_length),
1438                offsetof(xfs_agi_t, agi_count),
1439                offsetof(xfs_agi_t, agi_root),
1440                offsetof(xfs_agi_t, agi_level),
1441                offsetof(xfs_agi_t, agi_freecount),
1442                offsetof(xfs_agi_t, agi_newino),
1443                offsetof(xfs_agi_t, agi_dirino),
1444                offsetof(xfs_agi_t, agi_unlinked),
1445                sizeof(xfs_agi_t)
1446        };
1447#ifdef DEBUG
1448        xfs_agi_t               *agi;   /* allocation group header */
1449
1450        agi = XFS_BUF_TO_AGI(bp);
1451        ASSERT(agi->agi_magicnum == cpu_to_be32(XFS_AGI_MAGIC));
1452#endif
1453        /*
1454         * Compute byte offsets for the first and last fields.
1455         */
1456        xfs_btree_offsets(fields, offsets, XFS_AGI_NUM_BITS, &first, &last);
1457        /*
1458         * Log the allocation group inode header buffer.
1459         */
1460        xfs_trans_log_buf(tp, bp, first, last);
1461}
1462
1463#ifdef DEBUG
1464STATIC void
1465xfs_check_agi_unlinked(
1466        struct xfs_agi          *agi)
1467{
1468        int                     i;
1469
1470        for (i = 0; i < XFS_AGI_UNLINKED_BUCKETS; i++)
1471                ASSERT(agi->agi_unlinked[i]);
1472}
1473#else
1474#define xfs_check_agi_unlinked(agi)
1475#endif
1476
1477static void
1478xfs_agi_verify(
1479        struct xfs_buf  *bp)
1480{
1481        struct xfs_mount *mp = bp->b_target->bt_mount;
1482        struct xfs_agi  *agi = XFS_BUF_TO_AGI(bp);
1483        int             agi_ok;
1484
1485        /*
1486         * Validate the magic number of the agi block.
1487         */
1488        agi_ok = agi->agi_magicnum == cpu_to_be32(XFS_AGI_MAGIC) &&
1489                XFS_AGI_GOOD_VERSION(be32_to_cpu(agi->agi_versionnum));
1490
1491        /*
1492         * during growfs operations, the perag is not fully initialised,
1493         * so we can't use it for any useful checking. growfs ensures we can't
1494         * use it by using uncached buffers that don't have the perag attached
1495         * so we can detect and avoid this problem.
1496         */
1497        if (bp->b_pag)
1498                agi_ok = agi_ok && be32_to_cpu(agi->agi_seqno) ==
1499                                                bp->b_pag->pag_agno;
1500
1501        if (unlikely(XFS_TEST_ERROR(!agi_ok, mp, XFS_ERRTAG_IALLOC_READ_AGI,
1502                        XFS_RANDOM_IALLOC_READ_AGI))) {
1503                XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, agi);
1504                xfs_buf_ioerror(bp, EFSCORRUPTED);
1505        }
1506        xfs_check_agi_unlinked(agi);
1507}
1508
1509static void
1510xfs_agi_read_verify(
1511        struct xfs_buf  *bp)
1512{
1513        xfs_agi_verify(bp);
1514}
1515
1516static void
1517xfs_agi_write_verify(
1518        struct xfs_buf  *bp)
1519{
1520        xfs_agi_verify(bp);
1521}
1522
1523const struct xfs_buf_ops xfs_agi_buf_ops = {
1524        .verify_read = xfs_agi_read_verify,
1525        .verify_write = xfs_agi_write_verify,
1526};
1527
1528/*
1529 * Read in the allocation group header (inode allocation section)
1530 */
1531int
1532xfs_read_agi(
1533        struct xfs_mount        *mp,    /* file system mount structure */
1534        struct xfs_trans        *tp,    /* transaction pointer */
1535        xfs_agnumber_t          agno,   /* allocation group number */
1536        struct xfs_buf          **bpp)  /* allocation group hdr buf */
1537{
1538        int                     error;
1539
1540        ASSERT(agno != NULLAGNUMBER);
1541
1542        error = xfs_trans_read_buf(mp, tp, mp->m_ddev_targp,
1543                        XFS_AG_DADDR(mp, agno, XFS_AGI_DADDR(mp)),
1544                        XFS_FSS_TO_BB(mp, 1), 0, bpp, &xfs_agi_buf_ops);
1545        if (error)
1546                return error;
1547
1548        ASSERT(!xfs_buf_geterror(*bpp));
1549        xfs_buf_set_ref(*bpp, XFS_AGI_REF);
1550        return 0;
1551}
1552
1553int
1554xfs_ialloc_read_agi(
1555        struct xfs_mount        *mp,    /* file system mount structure */
1556        struct xfs_trans        *tp,    /* transaction pointer */
1557        xfs_agnumber_t          agno,   /* allocation group number */
1558        struct xfs_buf          **bpp)  /* allocation group hdr buf */
1559{
1560        struct xfs_agi          *agi;   /* allocation group header */
1561        struct xfs_perag        *pag;   /* per allocation group data */
1562        int                     error;
1563
1564        error = xfs_read_agi(mp, tp, agno, bpp);
1565        if (error)
1566                return error;
1567
1568        agi = XFS_BUF_TO_AGI(*bpp);
1569        pag = xfs_perag_get(mp, agno);
1570        if (!pag->pagi_init) {
1571                pag->pagi_freecount = be32_to_cpu(agi->agi_freecount);
1572                pag->pagi_count = be32_to_cpu(agi->agi_count);
1573                pag->pagi_init = 1;
1574        }
1575
1576        /*
1577         * It's possible for these to be out of sync if
1578         * we are in the middle of a forced shutdown.
1579         */
1580        ASSERT(pag->pagi_freecount == be32_to_cpu(agi->agi_freecount) ||
1581                XFS_FORCED_SHUTDOWN(mp));
1582        xfs_perag_put(pag);
1583        return 0;
1584}
1585
1586/*
1587 * Read in the agi to initialise the per-ag data in the mount structure
1588 */
1589int
1590xfs_ialloc_pagi_init(
1591        xfs_mount_t     *mp,            /* file system mount structure */
1592        xfs_trans_t     *tp,            /* transaction pointer */
1593        xfs_agnumber_t  agno)           /* allocation group number */
1594{
1595        xfs_buf_t       *bp = NULL;
1596        int             error;
1597
1598        error = xfs_ialloc_read_agi(mp, tp, agno, &bp);
1599        if (error)
1600                return error;
1601        if (bp)
1602                xfs_trans_brelse(tp, bp);
1603        return 0;
1604}
1605
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