diff options
Diffstat (limited to 'fs/xfs/libxfs/xfs_rmap_btree.c')
-rw-r--r-- | fs/xfs/libxfs/xfs_rmap_btree.c | 746 |
1 files changed, 746 insertions, 0 deletions
diff --git a/fs/xfs/libxfs/xfs_rmap_btree.c b/fs/xfs/libxfs/xfs_rmap_btree.c new file mode 100644 index 0000000000..6c81b20e97 --- /dev/null +++ b/fs/xfs/libxfs/xfs_rmap_btree.c @@ -0,0 +1,746 @@ +// 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]; +} + +/* + * Convert the ondisk record's offset field into the ondisk key's offset field. + * Fork and bmbt are significant parts of the rmap record key, but written + * status is merely a record attribute. + */ +static inline __be64 ondisk_rec_offset_to_key(const union xfs_btree_rec *rec) +{ + return rec->rmap.rm_offset & ~cpu_to_be64(XFS_RMAP_OFF_UNWRITTEN); +} + +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 = ondisk_rec_offset_to_key(rec); +} + +/* + * 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 = ondisk_rec_offset_to_key(rec); + 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]; +} + +/* + * Mask the appropriate parts of the ondisk key field for a key comparison. + * Fork and bmbt are significant parts of the rmap record key, but written + * status is merely a record attribute. + */ +static inline uint64_t offset_keymask(uint64_t offset) +{ + return offset & ~XFS_RMAP_OFF_UNWRITTEN; +} + +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 = offset_keymask(be64_to_cpu(kp->rm_offset)); + y = offset_keymask(xfs_rmap_irec_offset_pack(rec)); + 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 union xfs_btree_key *mask) +{ + const struct xfs_rmap_key *kp1 = &k1->rmap; + const struct xfs_rmap_key *kp2 = &k2->rmap; + int64_t d; + __u64 x, y; + + /* Doesn't make sense to mask off the physical space part */ + ASSERT(!mask || mask->rmap.rm_startblock); + + d = (int64_t)be32_to_cpu(kp1->rm_startblock) - + be32_to_cpu(kp2->rm_startblock); + if (d) + return d; + + if (!mask || mask->rmap.rm_owner) { + 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; + } + + if (!mask || mask->rmap.rm_offset) { + /* Doesn't make sense to allow offset but not owner */ + ASSERT(!mask || mask->rmap.rm_owner); + + x = offset_keymask(be64_to_cpu(kp1->rm_offset)); + y = offset_keymask(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 && xfs_perag_initialised_agf(pag)) { + 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 = offset_keymask(be64_to_cpu(k1->rmap.rm_offset)); + b = offset_keymask(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 = offset_keymask(be64_to_cpu(r1->rmap.rm_offset)); + b = offset_keymask(be64_to_cpu(r2->rmap.rm_offset)); + if (a <= b) + return 1; + return 0; +} + +STATIC enum xbtree_key_contig +xfs_rmapbt_keys_contiguous( + struct xfs_btree_cur *cur, + const union xfs_btree_key *key1, + const union xfs_btree_key *key2, + const union xfs_btree_key *mask) +{ + ASSERT(!mask || mask->rmap.rm_startblock); + + /* + * We only support checking contiguity of the physical space component. + * If any callers ever need more specificity than that, they'll have to + * implement it here. + */ + ASSERT(!mask || (!mask->rmap.rm_owner && !mask->rmap.rm_offset)); + + return xbtree_key_contig(be32_to_cpu(key1->rmap.rm_startblock), + be32_to_cpu(key2->rmap.rm_startblock)); +} + +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, + .keys_contiguous = xfs_rmapbt_keys_contiguous, +}; + +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; + + cur->bc_ag.pag = xfs_perag_hold(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; +} |