fs/xfs/libxfs/xfs_ag.c

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3  * Copyright (c) 2000-2005 Silicon Graphics, Inc.
   4  * Copyright (c) 2018 Red Hat, Inc.
   5  * All rights reserved.
   6  */
   7
   8 #include "xfs.h"
   9 #include "xfs_fs.h"
  10 #include "xfs_shared.h"
  11 #include "xfs_format.h"
  12 #include "xfs_trans_resv.h"
  13 #include "xfs_bit.h"
  14 #include "xfs_sb.h"
  15 #include "xfs_mount.h"
  16 #include "xfs_btree.h"
  17 #include "xfs_alloc_btree.h"
  18 #include "xfs_rmap_btree.h"
  19 #include "xfs_alloc.h"
  20 #include "xfs_ialloc.h"
  21 #include "xfs_rmap.h"
  22 #include "xfs_ag.h"
  23 #include "xfs_ag_resv.h"
  24 #include "xfs_health.h"
  25
  26 static int
  27 xfs_get_aghdr_buf(
  28         struct xfs_mount        *mp,
  29         xfs_daddr_t             blkno,
  30         size_t                  numblks,
  31         struct xfs_buf          **bpp,
  32         const struct xfs_buf_ops *ops)
  33 {
  34         struct xfs_buf          *bp;
  35         int                     error;
  36
  37         error = xfs_buf_get_uncached(mp->m_ddev_targp, numblks, 0, &bp);
  38         if (error)
  39                 return error;
  40
  41         xfs_buf_zero(bp, 0, BBTOB(bp->b_length));
  42         bp->b_bn = blkno;
  43         bp->b_maps[0].bm_bn = blkno;
  44         bp->b_ops = ops;
  45
  46         *bpp = bp;
  47         return 0;
  48 }
  49
  50 static inline bool is_log_ag(struct xfs_mount *mp, struct aghdr_init_data *id)
  51 {
  52         return mp->m_sb.sb_logstart > 0 &&
  53                id->agno == XFS_FSB_TO_AGNO(mp, mp->m_sb.sb_logstart);
  54 }
  55
  56 /*
  57  * Generic btree root block init function
  58  */
  59 static void
  60 xfs_btroot_init(
  61         struct xfs_mount        *mp,
  62         struct xfs_buf          *bp,
  63         struct aghdr_init_data  *id)
  64 {
  65         xfs_btree_init_block(mp, bp, id->type, 0, 0, id->agno);
  66 }
  67
  68 /* Finish initializing a free space btree. */
  69 static void
  70 xfs_freesp_init_recs(
  71         struct xfs_mount        *mp,
  72         struct xfs_buf          *bp,
  73         struct aghdr_init_data  *id)
  74 {
  75         struct xfs_alloc_rec    *arec;
  76         struct xfs_btree_block  *block = XFS_BUF_TO_BLOCK(bp);
  77
  78         arec = XFS_ALLOC_REC_ADDR(mp, XFS_BUF_TO_BLOCK(bp), 1);
  79         arec->ar_startblock = cpu_to_be32(mp->m_ag_prealloc_blocks);
  80
  81         if (is_log_ag(mp, id)) {
  82                 struct xfs_alloc_rec    *nrec;
  83                 xfs_agblock_t           start = XFS_FSB_TO_AGBNO(mp,
  84                                                         mp->m_sb.sb_logstart);
  85
  86                 ASSERT(start >= mp->m_ag_prealloc_blocks);
  87                 if (start != mp->m_ag_prealloc_blocks) {
  88                         /*
  89                          * Modify first record to pad stripe align of log
  90                          */
  91                         arec->ar_blockcount = cpu_to_be32(start -
  92                                                 mp->m_ag_prealloc_blocks);
  93                         nrec = arec + 1;
  94
  95                         /*
  96                          * Insert second record at start of internal log
  97                          * which then gets trimmed.
  98                          */
  99                         nrec->ar_startblock = cpu_to_be32(
 100                                         be32_to_cpu(arec->ar_startblock) +
 101                                         be32_to_cpu(arec->ar_blockcount));
 102                         arec = nrec;
 103                         be16_add_cpu(&block->bb_numrecs, 1);
 104                 }
 105                 /*
 106                  * Change record start to after the internal log
 107                  */
 108                 be32_add_cpu(&arec->ar_startblock, mp->m_sb.sb_logblocks);
 109         }
 110
 111         /*
 112          * Calculate the record block count and check for the case where
 113          * the log might have consumed all available space in the AG. If
 114          * so, reset the record count to 0 to avoid exposure of an invalid
 115          * record start block.
 116          */
 117         arec->ar_blockcount = cpu_to_be32(id->agsize -
 118                                           be32_to_cpu(arec->ar_startblock));
 119         if (!arec->ar_blockcount)
 120                 block->bb_numrecs = 0;
 121 }
 122
 123 /*
 124  * Alloc btree root block init functions
 125  */
 126 static void
 127 xfs_bnoroot_init(
 128         struct xfs_mount        *mp,
 129         struct xfs_buf          *bp,
 130         struct aghdr_init_data  *id)
 131 {
 132         xfs_btree_init_block(mp, bp, XFS_BTNUM_BNO, 0, 1, id->agno);
 133         xfs_freesp_init_recs(mp, bp, id);
 134 }
 135
 136 static void
 137 xfs_cntroot_init(
 138         struct xfs_mount        *mp,
 139         struct xfs_buf          *bp,
 140         struct aghdr_init_data  *id)
 141 {
 142         xfs_btree_init_block(mp, bp, XFS_BTNUM_CNT, 0, 1, id->agno);
 143         xfs_freesp_init_recs(mp, bp, id);
 144 }
 145
 146 /*
 147  * Reverse map root block init
 148  */
 149 static void
 150 xfs_rmaproot_init(
 151         struct xfs_mount        *mp,
 152         struct xfs_buf          *bp,
 153         struct aghdr_init_data  *id)
 154 {
 155         struct xfs_btree_block  *block = XFS_BUF_TO_BLOCK(bp);
 156         struct xfs_rmap_rec     *rrec;
 157
 158         xfs_btree_init_block(mp, bp, XFS_BTNUM_RMAP, 0, 4, id->agno);
 159
 160         /*
 161          * mark the AG header regions as static metadata The BNO
 162          * btree block is the first block after the headers, so
 163          * it's location defines the size of region the static
 164          * metadata consumes.
 165          *
 166          * Note: unlike mkfs, we never have to account for log
 167          * space when growing the data regions
 168          */
 169         rrec = XFS_RMAP_REC_ADDR(block, 1);
 170         rrec->rm_startblock = 0;
 171         rrec->rm_blockcount = cpu_to_be32(XFS_BNO_BLOCK(mp));
 172         rrec->rm_owner = cpu_to_be64(XFS_RMAP_OWN_FS);
 173         rrec->rm_offset = 0;
 174
 175         /* account freespace btree root blocks */
 176         rrec = XFS_RMAP_REC_ADDR(block, 2);
 177         rrec->rm_startblock = cpu_to_be32(XFS_BNO_BLOCK(mp));
 178         rrec->rm_blockcount = cpu_to_be32(2);
 179         rrec->rm_owner = cpu_to_be64(XFS_RMAP_OWN_AG);
 180         rrec->rm_offset = 0;
 181
 182         /* account inode btree root blocks */
 183         rrec = XFS_RMAP_REC_ADDR(block, 3);
 184         rrec->rm_startblock = cpu_to_be32(XFS_IBT_BLOCK(mp));
 185         rrec->rm_blockcount = cpu_to_be32(XFS_RMAP_BLOCK(mp) -
 186                                           XFS_IBT_BLOCK(mp));
 187         rrec->rm_owner = cpu_to_be64(XFS_RMAP_OWN_INOBT);
 188         rrec->rm_offset = 0;
 189
 190         /* account for rmap btree root */
 191         rrec = XFS_RMAP_REC_ADDR(block, 4);
 192         rrec->rm_startblock = cpu_to_be32(XFS_RMAP_BLOCK(mp));
 193         rrec->rm_blockcount = cpu_to_be32(1);
 194         rrec->rm_owner = cpu_to_be64(XFS_RMAP_OWN_AG);
 195         rrec->rm_offset = 0;
 196
 197         /* account for refc btree root */
 198         if (xfs_sb_version_hasreflink(&mp->m_sb)) {
 199                 rrec = XFS_RMAP_REC_ADDR(block, 5);
 200                 rrec->rm_startblock = cpu_to_be32(xfs_refc_block(mp));
 201                 rrec->rm_blockcount = cpu_to_be32(1);
 202                 rrec->rm_owner = cpu_to_be64(XFS_RMAP_OWN_REFC);
 203                 rrec->rm_offset = 0;
 204                 be16_add_cpu(&block->bb_numrecs, 1);
 205         }
 206
 207         /* account for the log space */
 208         if (is_log_ag(mp, id)) {
 209                 rrec = XFS_RMAP_REC_ADDR(block,
 210                                 be16_to_cpu(block->bb_numrecs) + 1);
 211                 rrec->rm_startblock = cpu_to_be32(
 212                                 XFS_FSB_TO_AGBNO(mp, mp->m_sb.sb_logstart));
 213                 rrec->rm_blockcount = cpu_to_be32(mp->m_sb.sb_logblocks);
 214                 rrec->rm_owner = cpu_to_be64(XFS_RMAP_OWN_LOG);
 215                 rrec->rm_offset = 0;
 216                 be16_add_cpu(&block->bb_numrecs, 1);
 217         }
 218 }
 219
 220 /*
 221  * Initialise new secondary superblocks with the pre-grow geometry, but mark
 222  * them as "in progress" so we know they haven't yet been activated. This will
 223  * get cleared when the update with the new geometry information is done after
 224  * changes to the primary are committed. This isn't strictly necessary, but we
 225  * get it for free with the delayed buffer write lists and it means we can tell
 226  * if a grow operation didn't complete properly after the fact.
 227  */
 228 static void
 229 xfs_sbblock_init(
 230         struct xfs_mount        *mp,
 231         struct xfs_buf          *bp,
 232         struct aghdr_init_data  *id)
 233 {
 234         struct xfs_dsb          *dsb = bp->b_addr;
 235
 236         xfs_sb_to_disk(dsb, &mp->m_sb);
 237         dsb->sb_inprogress = 1;
 238 }
 239
 240 static void
 241 xfs_agfblock_init(
 242         struct xfs_mount        *mp,
 243         struct xfs_buf          *bp,
 244         struct aghdr_init_data  *id)
 245 {
 246         struct xfs_agf          *agf = bp->b_addr;
 247         xfs_extlen_t            tmpsize;
 248
 249         agf->agf_magicnum = cpu_to_be32(XFS_AGF_MAGIC);
 250         agf->agf_versionnum = cpu_to_be32(XFS_AGF_VERSION);
 251         agf->agf_seqno = cpu_to_be32(id->agno);
 252         agf->agf_length = cpu_to_be32(id->agsize);
 253         agf->agf_roots[XFS_BTNUM_BNOi] = cpu_to_be32(XFS_BNO_BLOCK(mp));
 254         agf->agf_roots[XFS_BTNUM_CNTi] = cpu_to_be32(XFS_CNT_BLOCK(mp));
 255         agf->agf_levels[XFS_BTNUM_BNOi] = cpu_to_be32(1);
 256         agf->agf_levels[XFS_BTNUM_CNTi] = cpu_to_be32(1);
 257         if (xfs_sb_version_hasrmapbt(&mp->m_sb)) {
 258                 agf->agf_roots[XFS_BTNUM_RMAPi] =
 259                                         cpu_to_be32(XFS_RMAP_BLOCK(mp));
 260                 agf->agf_levels[XFS_BTNUM_RMAPi] = cpu_to_be32(1);
 261                 agf->agf_rmap_blocks = cpu_to_be32(1);
 262         }
 263
 264         agf->agf_flfirst = cpu_to_be32(1);
 265         agf->agf_fllast = 0;
 266         agf->agf_flcount = 0;
 267         tmpsize = id->agsize - mp->m_ag_prealloc_blocks;
 268         agf->agf_freeblks = cpu_to_be32(tmpsize);
 269         agf->agf_longest = cpu_to_be32(tmpsize);
 270         if (xfs_sb_version_hascrc(&mp->m_sb))
 271                 uuid_copy(&agf->agf_uuid, &mp->m_sb.sb_meta_uuid);
 272         if (xfs_sb_version_hasreflink(&mp->m_sb)) {
 273                 agf->agf_refcount_root = cpu_to_be32(
 274                                 xfs_refc_block(mp));
 275                 agf->agf_refcount_level = cpu_to_be32(1);
 276                 agf->agf_refcount_blocks = cpu_to_be32(1);
 277         }
 278
 279         if (is_log_ag(mp, id)) {
 280                 int64_t logblocks = mp->m_sb.sb_logblocks;
 281
 282                 be32_add_cpu(&agf->agf_freeblks, -logblocks);
 283                 agf->agf_longest = cpu_to_be32(id->agsize -
 284                         XFS_FSB_TO_AGBNO(mp, mp->m_sb.sb_logstart) - logblocks);
 285         }
 286 }
 287
 288 static void
 289 xfs_agflblock_init(
 290         struct xfs_mount        *mp,
 291         struct xfs_buf          *bp,
 292         struct aghdr_init_data  *id)
 293 {
 294         struct xfs_agfl         *agfl = XFS_BUF_TO_AGFL(bp);
 295         __be32                  *agfl_bno;
 296         int                     bucket;
 297
 298         if (xfs_sb_version_hascrc(&mp->m_sb)) {
 299                 agfl->agfl_magicnum = cpu_to_be32(XFS_AGFL_MAGIC);
 300                 agfl->agfl_seqno = cpu_to_be32(id->agno);
 301                 uuid_copy(&agfl->agfl_uuid, &mp->m_sb.sb_meta_uuid);
 302         }
 303
 304         agfl_bno = xfs_buf_to_agfl_bno(bp);
 305         for (bucket = 0; bucket < xfs_agfl_size(mp); bucket++)
 306                 agfl_bno[bucket] = cpu_to_be32(NULLAGBLOCK);
 307 }
 308
 309 static void
 310 xfs_agiblock_init(
 311         struct xfs_mount        *mp,
 312         struct xfs_buf          *bp,
 313         struct aghdr_init_data  *id)
 314 {
 315         struct xfs_agi          *agi = bp->b_addr;
 316         int                     bucket;
 317
 318         agi->agi_magicnum = cpu_to_be32(XFS_AGI_MAGIC);
 319         agi->agi_versionnum = cpu_to_be32(XFS_AGI_VERSION);
 320         agi->agi_seqno = cpu_to_be32(id->agno);
 321         agi->agi_length = cpu_to_be32(id->agsize);
 322         agi->agi_count = 0;
 323         agi->agi_root = cpu_to_be32(XFS_IBT_BLOCK(mp));
 324         agi->agi_level = cpu_to_be32(1);
 325         agi->agi_freecount = 0;
 326         agi->agi_newino = cpu_to_be32(NULLAGINO);
 327         agi->agi_dirino = cpu_to_be32(NULLAGINO);
 328         if (xfs_sb_version_hascrc(&mp->m_sb))
 329                 uuid_copy(&agi->agi_uuid, &mp->m_sb.sb_meta_uuid);
 330         if (xfs_sb_version_hasfinobt(&mp->m_sb)) {
 331                 agi->agi_free_root = cpu_to_be32(XFS_FIBT_BLOCK(mp));
 332                 agi->agi_free_level = cpu_to_be32(1);
 333         }
 334         for (bucket = 0; bucket < XFS_AGI_UNLINKED_BUCKETS; bucket++)
 335                 agi->agi_unlinked[bucket] = cpu_to_be32(NULLAGINO);
 336         if (xfs_sb_version_hasinobtcounts(&mp->m_sb)) {
 337                 agi->agi_iblocks = cpu_to_be32(1);
 338                 if (xfs_sb_version_hasfinobt(&mp->m_sb))
 339                         agi->agi_fblocks = cpu_to_be32(1);
 340         }
 341 }
 342
 343 typedef void (*aghdr_init_work_f)(struct xfs_mount *mp, struct xfs_buf *bp,
 344                                   struct aghdr_init_data *id);
 345 static int
 346 xfs_ag_init_hdr(
 347         struct xfs_mount        *mp,
 348         struct aghdr_init_data  *id,
 349         aghdr_init_work_f       work,
 350         const struct xfs_buf_ops *ops)
 351 {
 352         struct xfs_buf          *bp;
 353         int                     error;
 354
 355         error = xfs_get_aghdr_buf(mp, id->daddr, id->numblks, &bp, ops);
 356         if (error)
 357                 return error;
 358
 359         (*work)(mp, bp, id);
 360
 361         xfs_buf_delwri_queue(bp, &id->buffer_list);
 362         xfs_buf_relse(bp);
 363         return 0;
 364 }
 365
 366 struct xfs_aghdr_grow_data {
 367         xfs_daddr_t             daddr;
 368         size_t                  numblks;
 369         const struct xfs_buf_ops *ops;
 370         aghdr_init_work_f       work;
 371         xfs_btnum_t             type;
 372         bool                    need_init;
 373 };
 374
 375 /*
 376  * Prepare new AG headers to be written to disk. We use uncached buffers here,
 377  * as it is assumed these new AG headers are currently beyond the currently
 378  * valid filesystem address space. Using cached buffers would trip over EOFS
 379  * corruption detection alogrithms in the buffer cache lookup routines.
 380  *
 381  * This is a non-transactional function, but the prepared buffers are added to a
 382  * delayed write buffer list supplied by the caller so they can submit them to
 383  * disk and wait on them as required.
 384  */
 385 int
 386 xfs_ag_init_headers(
 387         struct xfs_mount        *mp,
 388         struct aghdr_init_data  *id)
 389
 390 {
 391         struct xfs_aghdr_grow_data aghdr_data[] = {
 392         { /* SB */
 393                 .daddr = XFS_AG_DADDR(mp, id->agno, XFS_SB_DADDR),
 394                 .numblks = XFS_FSS_TO_BB(mp, 1),
 395                 .ops = &xfs_sb_buf_ops,
 396                 .work = &xfs_sbblock_init,
 397                 .need_init = true
 398         },
 399         { /* AGF */
 400                 .daddr = XFS_AG_DADDR(mp, id->agno, XFS_AGF_DADDR(mp)),
 401                 .numblks = XFS_FSS_TO_BB(mp, 1),
 402                 .ops = &xfs_agf_buf_ops,
 403                 .work = &xfs_agfblock_init,
 404                 .need_init = true
 405         },
 406         { /* AGFL */
 407                 .daddr = XFS_AG_DADDR(mp, id->agno, XFS_AGFL_DADDR(mp)),
 408                 .numblks = XFS_FSS_TO_BB(mp, 1),
 409                 .ops = &xfs_agfl_buf_ops,
 410                 .work = &xfs_agflblock_init,
 411                 .need_init = true
 412         },
 413         { /* AGI */
 414                 .daddr = XFS_AG_DADDR(mp, id->agno, XFS_AGI_DADDR(mp)),
 415                 .numblks = XFS_FSS_TO_BB(mp, 1),
 416                 .ops = &xfs_agi_buf_ops,
 417                 .work = &xfs_agiblock_init,
 418                 .need_init = true
 419         },
 420         { /* BNO root block */
 421                 .daddr = XFS_AGB_TO_DADDR(mp, id->agno, XFS_BNO_BLOCK(mp)),
 422                 .numblks = BTOBB(mp->m_sb.sb_blocksize),
 423                 .ops = &xfs_bnobt_buf_ops,
 424                 .work = &xfs_bnoroot_init,
 425                 .need_init = true
 426         },
 427         { /* CNT root block */
 428                 .daddr = XFS_AGB_TO_DADDR(mp, id->agno, XFS_CNT_BLOCK(mp)),
 429                 .numblks = BTOBB(mp->m_sb.sb_blocksize),
 430                 .ops = &xfs_cntbt_buf_ops,
 431                 .work = &xfs_cntroot_init,
 432                 .need_init = true
 433         },
 434         { /* INO root block */
 435                 .daddr = XFS_AGB_TO_DADDR(mp, id->agno, XFS_IBT_BLOCK(mp)),
 436                 .numblks = BTOBB(mp->m_sb.sb_blocksize),
 437                 .ops = &xfs_inobt_buf_ops,
 438                 .work = &xfs_btroot_init,
 439                 .type = XFS_BTNUM_INO,
 440                 .need_init = true
 441         },
 442         { /* FINO root block */
 443                 .daddr = XFS_AGB_TO_DADDR(mp, id->agno, XFS_FIBT_BLOCK(mp)),
 444                 .numblks = BTOBB(mp->m_sb.sb_blocksize),
 445                 .ops = &xfs_finobt_buf_ops,
 446                 .work = &xfs_btroot_init,
 447                 .type = XFS_BTNUM_FINO,
 448                 .need_init =  xfs_sb_version_hasfinobt(&mp->m_sb)
 449         },
 450         { /* RMAP root block */
 451                 .daddr = XFS_AGB_TO_DADDR(mp, id->agno, XFS_RMAP_BLOCK(mp)),
 452                 .numblks = BTOBB(mp->m_sb.sb_blocksize),
 453                 .ops = &xfs_rmapbt_buf_ops,
 454                 .work = &xfs_rmaproot_init,
 455                 .need_init = xfs_sb_version_hasrmapbt(&mp->m_sb)
 456         },
 457         { /* REFC root block */
 458                 .daddr = XFS_AGB_TO_DADDR(mp, id->agno, xfs_refc_block(mp)),
 459                 .numblks = BTOBB(mp->m_sb.sb_blocksize),
 460                 .ops = &xfs_refcountbt_buf_ops,
 461                 .work = &xfs_btroot_init,
 462                 .type = XFS_BTNUM_REFC,
 463                 .need_init = xfs_sb_version_hasreflink(&mp->m_sb)
 464         },
 465         { /* NULL terminating block */
 466                 .daddr = XFS_BUF_DADDR_NULL,
 467         }
 468         };
 469         struct  xfs_aghdr_grow_data *dp;
 470         int                     error = 0;
 471
 472         /* Account for AG free space in new AG */
 473         id->nfree += id->agsize - mp->m_ag_prealloc_blocks;
 474         for (dp = &aghdr_data[0]; dp->daddr != XFS_BUF_DADDR_NULL; dp++) {
 475                 if (!dp->need_init)
 476                         continue;
 477
 478                 id->daddr = dp->daddr;
 479                 id->numblks = dp->numblks;
 480                 id->type = dp->type;
 481                 error = xfs_ag_init_hdr(mp, id, dp->work, dp->ops);
 482                 if (error)
 483                         break;
 484         }
 485         return error;
 486 }
 487
 488 /*
 489  * Extent the AG indicated by the @id by the length passed in
 490  */
 491 int
 492 xfs_ag_extend_space(
 493         struct xfs_mount        *mp,
 494         struct xfs_trans        *tp,
 495         struct aghdr_init_data  *id,
 496         xfs_extlen_t            len)
 497 {
 498         struct xfs_buf          *bp;
 499         struct xfs_agi          *agi;
 500         struct xfs_agf          *agf;
 501         int                     error;
 502
 503         /*
 504          * Change the agi length.
 505          */
 506         error = xfs_ialloc_read_agi(mp, tp, id->agno, &bp);
 507         if (error)
 508                 return error;
 509
 510         agi = bp->b_addr;
 511         be32_add_cpu(&agi->agi_length, len);
 512         ASSERT(id->agno == mp->m_sb.sb_agcount - 1 ||
 513                be32_to_cpu(agi->agi_length) == mp->m_sb.sb_agblocks);
 514         xfs_ialloc_log_agi(tp, bp, XFS_AGI_LENGTH);
 515
 516         /*
 517          * Change agf length.
 518          */
 519         error = xfs_alloc_read_agf(mp, tp, id->agno, 0, &bp);
 520         if (error)
 521                 return error;
 522
 523         agf = bp->b_addr;
 524         be32_add_cpu(&agf->agf_length, len);
 525         ASSERT(agf->agf_length == agi->agi_length);
 526         xfs_alloc_log_agf(tp, bp, XFS_AGF_LENGTH);
 527
 528         /*
 529          * Free the new space.
 530          *
 531          * XFS_RMAP_OINFO_SKIP_UPDATE is used here to tell the rmap btree that
 532          * this doesn't actually exist in the rmap btree.
 533          */
 534         error = xfs_rmap_free(tp, bp, id->agno,
 535                                 be32_to_cpu(agf->agf_length) - len,
 536                                 len, &XFS_RMAP_OINFO_SKIP_UPDATE);
 537         if (error)
 538                 return error;
 539
 540         return  xfs_free_extent(tp, XFS_AGB_TO_FSB(mp, id->agno,
 541                                         be32_to_cpu(agf->agf_length) - len),
 542                                 len, &XFS_RMAP_OINFO_SKIP_UPDATE,
 543                                 XFS_AG_RESV_NONE);
 544 }
 545
 546 /* Retrieve AG geometry. */
 547 int
 548 xfs_ag_get_geometry(
 549         struct xfs_mount        *mp,
 550         xfs_agnumber_t          agno,
 551         struct xfs_ag_geometry  *ageo)
 552 {
 553         struct xfs_buf          *agi_bp;
 554         struct xfs_buf          *agf_bp;
 555         struct xfs_agi          *agi;
 556         struct xfs_agf          *agf;
 557         struct xfs_perag        *pag;
 558         unsigned int            freeblks;
 559         int                     error;
 560
 561         if (agno >= mp->m_sb.sb_agcount)
 562                 return -EINVAL;
 563
 564         /* Lock the AG headers. */
 565         error = xfs_ialloc_read_agi(mp, NULL, agno, &agi_bp);
 566         if (error)
 567                 return error;
 568         error = xfs_alloc_read_agf(mp, NULL, agno, 0, &agf_bp);
 569         if (error)
 570                 goto out_agi;
 571
 572         pag = agi_bp->b_pag;
 573
 574         /* Fill out form. */
 575         memset(ageo, 0, sizeof(*ageo));
 576         ageo->ag_number = agno;
 577
 578         agi = agi_bp->b_addr;
 579         ageo->ag_icount = be32_to_cpu(agi->agi_count);
 580         ageo->ag_ifree = be32_to_cpu(agi->agi_freecount);
 581
 582         agf = agf_bp->b_addr;
 583         ageo->ag_length = be32_to_cpu(agf->agf_length);
 584         freeblks = pag->pagf_freeblks +
 585                    pag->pagf_flcount +
 586                    pag->pagf_btreeblks -
 587                    xfs_ag_resv_needed(pag, XFS_AG_RESV_NONE);
 588         ageo->ag_freeblks = freeblks;
 589         xfs_ag_geom_health(pag, ageo);
 590
 591         /* Release resources. */
 592         xfs_buf_relse(agf_bp);
 593 out_agi:
 594         xfs_buf_relse(agi_bp);
 595         return error;
 596 }