OSCL-LXR linux-6.0.1/​fs/​xfs/​libxfs/​xfs_rmap_btree.c	Source navigation Diff markup Identifier search General search
	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 // SPDX-License-Identifier: GPL-2.0
 /*
  * Copyright (c) 2014 Red Hat, Inc.
  * All Rights Reserved.
  */
 #include "xfs.h"
 #include "xfs_fs.h"
 #include "xfs_shared.h"
 #include "xfs_format.h"
 #include "xfs_log_format.h"
 #include "xfs_trans_resv.h"
 #include "xfs_mount.h"
 #include "xfs_trans.h"
 #include "xfs_alloc.h"
 #include "xfs_btree.h"
 #include "xfs_btree_staging.h"
 #include "xfs_rmap.h"
 #include "xfs_rmap_btree.h"
 #include "xfs_trace.h"
 #include "xfs_error.h"
 #include "xfs_extent_busy.h"
 #include "xfs_ag.h"
 #include "xfs_ag_resv.h"
 
 static struct kmem_cache    *xfs_rmapbt_cur_cache;
 
 /*
  * Reverse map btree.
  *
  * This is a per-ag tree used to track the owner(s) of a given extent. With
  * reflink it is possible for there to be multiple owners, which is a departure
  * from classic XFS. Owner records for data extents are inserted when the
  * extent is mapped and removed when an extent is unmapped.  Owner records for
  * all other block types (i.e. metadata) are inserted when an extent is
  * allocated and removed when an extent is freed. There can only be one owner
  * of a metadata extent, usually an inode or some other metadata structure like
  * an AG btree.
  *
  * The rmap btree is part of the free space management, so blocks for the tree
  * are sourced from the agfl. Hence we need transaction reservation support for
  * this tree so that the freelist is always large enough. This also impacts on
  * the minimum space we need to leave free in the AG.
  *
  * The tree is ordered by [ag block, owner, offset]. This is a large key size,
  * but it is the only way to enforce unique keys when a block can be owned by
  * multiple files at any offset. There's no need to order/search by extent
  * size for online updating/management of the tree. It is intended that most
  * reverse lookups will be to find the owner(s) of a particular block, or to
  * try to recover tree and file data from corrupt primary metadata.
  */
 
 static struct xfs_btree_cur *
 xfs_rmapbt_dup_cursor(
     struct xfs_btree_cur    *cur)
 {
     return xfs_rmapbt_init_cursor(cur->bc_mp, cur->bc_tp,
                 cur->bc_ag.agbp, cur->bc_ag.pag);
 }
 
 STATIC void
 xfs_rmapbt_set_root(
     struct xfs_btree_cur        *cur,
     const union xfs_btree_ptr   *ptr,
     int             inc)
 {
     struct xfs_buf      *agbp = cur->bc_ag.agbp;
     struct xfs_agf      *agf = agbp->b_addr;
     int         btnum = cur->bc_btnum;
 
     ASSERT(ptr->s != 0);
 
     agf->agf_roots[btnum] = ptr->s;
     be32_add_cpu(&agf->agf_levels[btnum], inc);
     cur->bc_ag.pag->pagf_levels[btnum] += inc;
 
     xfs_alloc_log_agf(cur->bc_tp, agbp, XFS_AGF_ROOTS | XFS_AGF_LEVELS);
 }
 
 STATIC int
 xfs_rmapbt_alloc_block(
     struct xfs_btree_cur        *cur,
     const union xfs_btree_ptr   *start,
     union xfs_btree_ptr     *new,
     int             *stat)
 {
     struct xfs_buf      *agbp = cur->bc_ag.agbp;
     struct xfs_agf      *agf = agbp->b_addr;
     struct xfs_perag    *pag = cur->bc_ag.pag;
     int         error;
     xfs_agblock_t       bno;
 
     /* Allocate the new block from the freelist. If we can't, give up.  */
     error = xfs_alloc_get_freelist(pag, cur->bc_tp, cur->bc_ag.agbp,
                        &bno, 1);
     if (error)
         return error;
 
     trace_xfs_rmapbt_alloc_block(cur->bc_mp, pag->pag_agno, bno, 1);
     if (bno == NULLAGBLOCK) {
         *stat = 0;
         return 0;
     }
 
     xfs_extent_busy_reuse(cur->bc_mp, pag, bno, 1, false);
 
     new->s = cpu_to_be32(bno);
     be32_add_cpu(&agf->agf_rmap_blocks, 1);
     xfs_alloc_log_agf(cur->bc_tp, agbp, XFS_AGF_RMAP_BLOCKS);
 
     xfs_ag_resv_rmapbt_alloc(cur->bc_mp, pag->pag_agno);
 
     *stat = 1;
     return 0;
 }
 
 STATIC int
 xfs_rmapbt_free_block(
     struct xfs_btree_cur    *cur,
     struct xfs_buf      *bp)
 {
     struct xfs_buf      *agbp = cur->bc_ag.agbp;
     struct xfs_agf      *agf = agbp->b_addr;
     struct xfs_perag    *pag = cur->bc_ag.pag;
     xfs_agblock_t       bno;
     int         error;
 
     bno = xfs_daddr_to_agbno(cur->bc_mp, xfs_buf_daddr(bp));
     trace_xfs_rmapbt_free_block(cur->bc_mp, pag->pag_agno,
             bno, 1);
     be32_add_cpu(&agf->agf_rmap_blocks, -1);
     xfs_alloc_log_agf(cur->bc_tp, agbp, XFS_AGF_RMAP_BLOCKS);
     error = xfs_alloc_put_freelist(pag, cur->bc_tp, agbp, NULL, bno, 1);
     if (error)
         return error;
 
     xfs_extent_busy_insert(cur->bc_tp, pag, bno, 1,
                   XFS_EXTENT_BUSY_SKIP_DISCARD);
 
     xfs_ag_resv_free_extent(pag, XFS_AG_RESV_RMAPBT, NULL, 1);
     return 0;
 }
 
 STATIC int
 xfs_rmapbt_get_minrecs(
     struct xfs_btree_cur    *cur,
     int         level)
 {
     return cur->bc_mp->m_rmap_mnr[level != 0];
 }
 
 STATIC int
 xfs_rmapbt_get_maxrecs(
     struct xfs_btree_cur    *cur,
     int         level)
 {
     return cur->bc_mp->m_rmap_mxr[level != 0];
 }
 
 STATIC void
 xfs_rmapbt_init_key_from_rec(
     union xfs_btree_key     *key,
     const union xfs_btree_rec   *rec)
 {
     key->rmap.rm_startblock = rec->rmap.rm_startblock;
     key->rmap.rm_owner = rec->rmap.rm_owner;
     key->rmap.rm_offset = rec->rmap.rm_offset;
 }
 
 /*
  * The high key for a reverse mapping record can be computed by shifting
  * the startblock and offset to the highest value that would still map
  * to that record.  In practice this means that we add blockcount-1 to
  * the startblock for all records, and if the record is for a data/attr
  * fork mapping, we add blockcount-1 to the offset too.
  */
 STATIC void
 xfs_rmapbt_init_high_key_from_rec(
     union xfs_btree_key     *key,
     const union xfs_btree_rec   *rec)
 {
     uint64_t            off;
     int             adj;
 
     adj = be32_to_cpu(rec->rmap.rm_blockcount) - 1;
 
     key->rmap.rm_startblock = rec->rmap.rm_startblock;
     be32_add_cpu(&key->rmap.rm_startblock, adj);
     key->rmap.rm_owner = rec->rmap.rm_owner;
     key->rmap.rm_offset = rec->rmap.rm_offset;
     if (XFS_RMAP_NON_INODE_OWNER(be64_to_cpu(rec->rmap.rm_owner)) ||
         XFS_RMAP_IS_BMBT_BLOCK(be64_to_cpu(rec->rmap.rm_offset)))
         return;
     off = be64_to_cpu(key->rmap.rm_offset);
     off = (XFS_RMAP_OFF(off) + adj) | (off & ~XFS_RMAP_OFF_MASK);
     key->rmap.rm_offset = cpu_to_be64(off);
 }
 
 STATIC void
 xfs_rmapbt_init_rec_from_cur(
     struct xfs_btree_cur    *cur,
     union xfs_btree_rec *rec)
 {
     rec->rmap.rm_startblock = cpu_to_be32(cur->bc_rec.r.rm_startblock);
     rec->rmap.rm_blockcount = cpu_to_be32(cur->bc_rec.r.rm_blockcount);
     rec->rmap.rm_owner = cpu_to_be64(cur->bc_rec.r.rm_owner);
     rec->rmap.rm_offset = cpu_to_be64(
             xfs_rmap_irec_offset_pack(&cur->bc_rec.r));
 }
 
 STATIC void
 xfs_rmapbt_init_ptr_from_cur(
     struct xfs_btree_cur    *cur,
     union xfs_btree_ptr *ptr)
 {
     struct xfs_agf      *agf = cur->bc_ag.agbp->b_addr;
 
     ASSERT(cur->bc_ag.pag->pag_agno == be32_to_cpu(agf->agf_seqno));
 
     ptr->s = agf->agf_roots[cur->bc_btnum];
 }
 
 STATIC int64_t
 xfs_rmapbt_key_diff(
     struct xfs_btree_cur        *cur,
     const union xfs_btree_key   *key)
 {
     struct xfs_rmap_irec        *rec = &cur->bc_rec.r;
     const struct xfs_rmap_key   *kp = &key->rmap;
     __u64               x, y;
     int64_t             d;
 
     d = (int64_t)be32_to_cpu(kp->rm_startblock) - rec->rm_startblock;
     if (d)
         return d;
 
     x = be64_to_cpu(kp->rm_owner);
     y = rec->rm_owner;
     if (x > y)
         return 1;
     else if (y > x)
         return -1;
 
     x = XFS_RMAP_OFF(be64_to_cpu(kp->rm_offset));
     y = rec->rm_offset;
     if (x > y)
         return 1;
     else if (y > x)
         return -1;
     return 0;
 }
 
 STATIC int64_t
 xfs_rmapbt_diff_two_keys(
     struct xfs_btree_cur        *cur,
     const union xfs_btree_key   *k1,
     const union xfs_btree_key   *k2)
 {
     const struct xfs_rmap_key   *kp1 = &k1->rmap;
     const struct xfs_rmap_key   *kp2 = &k2->rmap;
     int64_t             d;
     __u64               x, y;
 
     d = (int64_t)be32_to_cpu(kp1->rm_startblock) -
                be32_to_cpu(kp2->rm_startblock);
     if (d)
         return d;
 
     x = be64_to_cpu(kp1->rm_owner);
     y = be64_to_cpu(kp2->rm_owner);
     if (x > y)
         return 1;
     else if (y > x)
         return -1;
 
     x = XFS_RMAP_OFF(be64_to_cpu(kp1->rm_offset));
     y = XFS_RMAP_OFF(be64_to_cpu(kp2->rm_offset));
     if (x > y)
         return 1;
     else if (y > x)
         return -1;
     return 0;
 }
 
 static xfs_failaddr_t
 xfs_rmapbt_verify(
     struct xfs_buf      *bp)
 {
     struct xfs_mount    *mp = bp->b_mount;
     struct xfs_btree_block  *block = XFS_BUF_TO_BLOCK(bp);
     struct xfs_perag    *pag = bp->b_pag;
     xfs_failaddr_t      fa;
     unsigned int        level;
 
     /*
      * magic number and level verification
      *
      * During growfs operations, we can't verify the exact level or owner as
      * the perag is not fully initialised and hence not attached to the
      * buffer.  In this case, check against the maximum tree depth.
      *
      * Similarly, during log recovery we will have a perag structure
      * attached, but the agf information will not yet have been initialised
      * from the on disk AGF. Again, we can only check against maximum limits
      * in this case.
      */
     if (!xfs_verify_magic(bp, block->bb_magic))
         return __this_address;
 
     if (!xfs_has_rmapbt(mp))
         return __this_address;
     fa = xfs_btree_sblock_v5hdr_verify(bp);
     if (fa)
         return fa;
 
     level = be16_to_cpu(block->bb_level);
     if (pag && pag->pagf_init) {
         if (level >= pag->pagf_levels[XFS_BTNUM_RMAPi])
             return __this_address;
     } else if (level >= mp->m_rmap_maxlevels)
         return __this_address;
 
     return xfs_btree_sblock_verify(bp, mp->m_rmap_mxr[level != 0]);
 }
 
 static void
 xfs_rmapbt_read_verify(
     struct xfs_buf  *bp)
 {
     xfs_failaddr_t  fa;
 
     if (!xfs_btree_sblock_verify_crc(bp))
         xfs_verifier_error(bp, -EFSBADCRC, __this_address);
     else {
         fa = xfs_rmapbt_verify(bp);
         if (fa)
             xfs_verifier_error(bp, -EFSCORRUPTED, fa);
     }
 
     if (bp->b_error)
         trace_xfs_btree_corrupt(bp, _RET_IP_);
 }
 
 static void
 xfs_rmapbt_write_verify(
     struct xfs_buf  *bp)
 {
     xfs_failaddr_t  fa;
 
     fa = xfs_rmapbt_verify(bp);
     if (fa) {
         trace_xfs_btree_corrupt(bp, _RET_IP_);
         xfs_verifier_error(bp, -EFSCORRUPTED, fa);
         return;
     }
     xfs_btree_sblock_calc_crc(bp);
 
 }
 
 const struct xfs_buf_ops xfs_rmapbt_buf_ops = {
     .name           = "xfs_rmapbt",
     .magic          = { 0, cpu_to_be32(XFS_RMAP_CRC_MAGIC) },
     .verify_read        = xfs_rmapbt_read_verify,
     .verify_write       = xfs_rmapbt_write_verify,
     .verify_struct      = xfs_rmapbt_verify,
 };
 
 STATIC int
 xfs_rmapbt_keys_inorder(
     struct xfs_btree_cur        *cur,
     const union xfs_btree_key   *k1,
     const union xfs_btree_key   *k2)
 {
     uint32_t        x;
     uint32_t        y;
     uint64_t        a;
     uint64_t        b;
 
     x = be32_to_cpu(k1->rmap.rm_startblock);
     y = be32_to_cpu(k2->rmap.rm_startblock);
     if (x < y)
         return 1;
     else if (x > y)
         return 0;
     a = be64_to_cpu(k1->rmap.rm_owner);
     b = be64_to_cpu(k2->rmap.rm_owner);
     if (a < b)
         return 1;
     else if (a > b)
         return 0;
     a = XFS_RMAP_OFF(be64_to_cpu(k1->rmap.rm_offset));
     b = XFS_RMAP_OFF(be64_to_cpu(k2->rmap.rm_offset));
     if (a <= b)
         return 1;
     return 0;
 }
 
 STATIC int
 xfs_rmapbt_recs_inorder(
     struct xfs_btree_cur        *cur,
     const union xfs_btree_rec   *r1,
     const union xfs_btree_rec   *r2)
 {
     uint32_t        x;
     uint32_t        y;
     uint64_t        a;
     uint64_t        b;
 
     x = be32_to_cpu(r1->rmap.rm_startblock);
     y = be32_to_cpu(r2->rmap.rm_startblock);
     if (x < y)
         return 1;
     else if (x > y)
         return 0;
     a = be64_to_cpu(r1->rmap.rm_owner);
     b = be64_to_cpu(r2->rmap.rm_owner);
     if (a < b)
         return 1;
     else if (a > b)
         return 0;
     a = XFS_RMAP_OFF(be64_to_cpu(r1->rmap.rm_offset));
     b = XFS_RMAP_OFF(be64_to_cpu(r2->rmap.rm_offset));
     if (a <= b)
         return 1;
     return 0;
 }
 
 static const struct xfs_btree_ops xfs_rmapbt_ops = {
     .rec_len        = sizeof(struct xfs_rmap_rec),
     .key_len        = 2 * sizeof(struct xfs_rmap_key),
 
     .dup_cursor     = xfs_rmapbt_dup_cursor,
     .set_root       = xfs_rmapbt_set_root,
     .alloc_block        = xfs_rmapbt_alloc_block,
     .free_block     = xfs_rmapbt_free_block,
     .get_minrecs        = xfs_rmapbt_get_minrecs,
     .get_maxrecs        = xfs_rmapbt_get_maxrecs,
     .init_key_from_rec  = xfs_rmapbt_init_key_from_rec,
     .init_high_key_from_rec = xfs_rmapbt_init_high_key_from_rec,
     .init_rec_from_cur  = xfs_rmapbt_init_rec_from_cur,
     .init_ptr_from_cur  = xfs_rmapbt_init_ptr_from_cur,
     .key_diff       = xfs_rmapbt_key_diff,
     .buf_ops        = &xfs_rmapbt_buf_ops,
     .diff_two_keys      = xfs_rmapbt_diff_two_keys,
     .keys_inorder       = xfs_rmapbt_keys_inorder,
     .recs_inorder       = xfs_rmapbt_recs_inorder,
 };
 
 static struct xfs_btree_cur *
 xfs_rmapbt_init_common(
     struct xfs_mount    *mp,
     struct xfs_trans    *tp,
     struct xfs_perag    *pag)
 {
     struct xfs_btree_cur    *cur;
 
     /* Overlapping btree; 2 keys per pointer. */
     cur = xfs_btree_alloc_cursor(mp, tp, XFS_BTNUM_RMAP,
             mp->m_rmap_maxlevels, xfs_rmapbt_cur_cache);
     cur->bc_flags = XFS_BTREE_CRC_BLOCKS | XFS_BTREE_OVERLAPPING;
     cur->bc_statoff = XFS_STATS_CALC_INDEX(xs_rmap_2);
     cur->bc_ops = &xfs_rmapbt_ops;
 
     /* take a reference for the cursor */
     atomic_inc(&pag->pag_ref);
     cur->bc_ag.pag = pag;
 
     return cur;
 }
 
 /* Create a new reverse mapping btree cursor. */
 struct xfs_btree_cur *
 xfs_rmapbt_init_cursor(
     struct xfs_mount    *mp,
     struct xfs_trans    *tp,
     struct xfs_buf      *agbp,
     struct xfs_perag    *pag)
 {
     struct xfs_agf      *agf = agbp->b_addr;
     struct xfs_btree_cur    *cur;
 
     cur = xfs_rmapbt_init_common(mp, tp, pag);
     cur->bc_nlevels = be32_to_cpu(agf->agf_levels[XFS_BTNUM_RMAP]);
     cur->bc_ag.agbp = agbp;
     return cur;
 }
 
 /* Create a new reverse mapping btree cursor with a fake root for staging. */
 struct xfs_btree_cur *
 xfs_rmapbt_stage_cursor(
     struct xfs_mount    *mp,
     struct xbtree_afakeroot *afake,
     struct xfs_perag    *pag)
 {
     struct xfs_btree_cur    *cur;
 
     cur = xfs_rmapbt_init_common(mp, NULL, pag);
     xfs_btree_stage_afakeroot(cur, afake);
     return cur;
 }
 
 /*
  * Install a new reverse mapping btree root.  Caller is responsible for
  * invalidating and freeing the old btree blocks.
  */
 void
 xfs_rmapbt_commit_staged_btree(
     struct xfs_btree_cur    *cur,
     struct xfs_trans    *tp,
     struct xfs_buf      *agbp)
 {
     struct xfs_agf      *agf = agbp->b_addr;
     struct xbtree_afakeroot *afake = cur->bc_ag.afake;
 
     ASSERT(cur->bc_flags & XFS_BTREE_STAGING);
 
     agf->agf_roots[cur->bc_btnum] = cpu_to_be32(afake->af_root);
     agf->agf_levels[cur->bc_btnum] = cpu_to_be32(afake->af_levels);
     agf->agf_rmap_blocks = cpu_to_be32(afake->af_blocks);
     xfs_alloc_log_agf(tp, agbp, XFS_AGF_ROOTS | XFS_AGF_LEVELS |
                     XFS_AGF_RMAP_BLOCKS);
     xfs_btree_commit_afakeroot(cur, tp, agbp, &xfs_rmapbt_ops);
 }
 
 /* Calculate number of records in a reverse mapping btree block. */
 static inline unsigned int
 xfs_rmapbt_block_maxrecs(
     unsigned int        blocklen,
     bool            leaf)
 {
     if (leaf)
         return blocklen / sizeof(struct xfs_rmap_rec);
     return blocklen /
         (2 * sizeof(struct xfs_rmap_key) + sizeof(xfs_rmap_ptr_t));
 }
 
 /*
  * Calculate number of records in an rmap btree block.
  */
 int
 xfs_rmapbt_maxrecs(
     int         blocklen,
     int         leaf)
 {
     blocklen -= XFS_RMAP_BLOCK_LEN;
     return xfs_rmapbt_block_maxrecs(blocklen, leaf);
 }
 
 /* Compute the max possible height for reverse mapping btrees. */
 unsigned int
 xfs_rmapbt_maxlevels_ondisk(void)
 {
     unsigned int        minrecs[2];
     unsigned int        blocklen;
 
     blocklen = XFS_MIN_CRC_BLOCKSIZE - XFS_BTREE_SBLOCK_CRC_LEN;
 
     minrecs[0] = xfs_rmapbt_block_maxrecs(blocklen, true) / 2;
     minrecs[1] = xfs_rmapbt_block_maxrecs(blocklen, false) / 2;
 
     /*
      * Compute the asymptotic maxlevels for an rmapbt on any reflink fs.
      *
      * On a reflink filesystem, each AG block can have up to 2^32 (per the
      * refcount record format) owners, which means that theoretically we
      * could face up to 2^64 rmap records.  However, we're likely to run
      * out of blocks in the AG long before that happens, which means that
      * we must compute the max height based on what the btree will look
      * like if it consumes almost all the blocks in the AG due to maximal
      * sharing factor.
      */
     return xfs_btree_space_to_height(minrecs, XFS_MAX_CRC_AG_BLOCKS);
 }
 
 /* Compute the maximum height of an rmap btree. */
 void
 xfs_rmapbt_compute_maxlevels(
     struct xfs_mount        *mp)
 {
     if (!xfs_has_rmapbt(mp)) {
         mp->m_rmap_maxlevels = 0;
         return;
     }
 
     if (xfs_has_reflink(mp)) {
         /*
          * Compute the asymptotic maxlevels for an rmap btree on a
          * filesystem that supports reflink.
          *
          * On a reflink filesystem, each AG block can have up to 2^32
          * (per the refcount record format) owners, which means that
          * theoretically we could face up to 2^64 rmap records.
          * However, we're likely to run out of blocks in the AG long
          * before that happens, which means that we must compute the
          * max height based on what the btree will look like if it
          * consumes almost all the blocks in the AG due to maximal
          * sharing factor.
          */
         mp->m_rmap_maxlevels = xfs_btree_space_to_height(mp->m_rmap_mnr,
                 mp->m_sb.sb_agblocks);
     } else {
         /*
          * If there's no block sharing, compute the maximum rmapbt
          * height assuming one rmap record per AG block.
          */
         mp->m_rmap_maxlevels = xfs_btree_compute_maxlevels(
                 mp->m_rmap_mnr, mp->m_sb.sb_agblocks);
     }
     ASSERT(mp->m_rmap_maxlevels <= xfs_rmapbt_maxlevels_ondisk());
 }
 
 /* Calculate the refcount btree size for some records. */
 xfs_extlen_t
 xfs_rmapbt_calc_size(
     struct xfs_mount    *mp,
     unsigned long long  len)
 {
     return xfs_btree_calc_size(mp->m_rmap_mnr, len);
 }
 
 /*
  * Calculate the maximum refcount btree size.
  */
 xfs_extlen_t
 xfs_rmapbt_max_size(
     struct xfs_mount    *mp,
     xfs_agblock_t       agblocks)
 {
     /* Bail out if we're uninitialized, which can happen in mkfs. */
     if (mp->m_rmap_mxr[0] == 0)
         return 0;
 
     return xfs_rmapbt_calc_size(mp, agblocks);
 }
 
 /*
  * Figure out how many blocks to reserve and how many are used by this btree.
  */
 int
 xfs_rmapbt_calc_reserves(
     struct xfs_mount    *mp,
     struct xfs_trans    *tp,
     struct xfs_perag    *pag,
     xfs_extlen_t        *ask,
     xfs_extlen_t        *used)
 {
     struct xfs_buf      *agbp;
     struct xfs_agf      *agf;
     xfs_agblock_t       agblocks;
     xfs_extlen_t        tree_len;
     int         error;
 
     if (!xfs_has_rmapbt(mp))
         return 0;
 
     error = xfs_alloc_read_agf(pag, tp, 0, &agbp);
     if (error)
         return error;
 
     agf = agbp->b_addr;
     agblocks = be32_to_cpu(agf->agf_length);
     tree_len = be32_to_cpu(agf->agf_rmap_blocks);
     xfs_trans_brelse(tp, agbp);
 
     /*
      * The log is permanently allocated, so the space it occupies will
      * never be available for the kinds of things that would require btree
      * expansion.  We therefore can pretend the space isn't there.
      */
     if (xfs_ag_contains_log(mp, pag->pag_agno))
         agblocks -= mp->m_sb.sb_logblocks;
 
     /* Reserve 1% of the AG or enough for 1 block per record. */
     *ask += max(agblocks / 100, xfs_rmapbt_max_size(mp, agblocks));
     *used += tree_len;
 
     return error;
 }
 
 int __init
 xfs_rmapbt_init_cur_cache(void)
 {
     xfs_rmapbt_cur_cache = kmem_cache_create("xfs_rmapbt_cur",
             xfs_btree_cur_sizeof(xfs_rmapbt_maxlevels_ondisk()),
             0, 0, NULL);
 
     if (!xfs_rmapbt_cur_cache)
         return -ENOMEM;
     return 0;
 }
 
 void
 xfs_rmapbt_destroy_cur_cache(void)
 {
     kmem_cache_destroy(xfs_rmapbt_cur_cache);
     xfs_rmapbt_cur_cache = NULL;
 }

This page was automatically generated by the 2.1.0 LXR engine. The LXR team