root/fs/xfs/libxfs/xfs_ag.c

DEFINITIONS

1. xfs_get_aghdr_buf
2. is_log_ag
3. xfs_btroot_init
4. xfs_freesp_init_recs
5. xfs_bnoroot_init
6. xfs_cntroot_init
7. xfs_rmaproot_init
8. xfs_sbblock_init
9. xfs_agfblock_init
10. xfs_agflblock_init
11. xfs_agiblock_init
12. xfs_ag_init_hdr
13. xfs_ag_init_headers
14. xfs_ag_extend_space
15. xfs_ag_get_geometry

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