On Wed, Oct 09, 2019 at 09:48:27AM -0700, Darrick J. Wong wrote:
> From: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
>
> Add support for btree staging cursors for the per-AG btree types. This
> is needed both for online repair and also to convert xfs_repair to use
> btree bulk loading.
>
> Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
> ---
> fs/xfs/libxfs/xfs_alloc_btree.c | 93 ++++++++++++++++++++++++++++++------
> fs/xfs/libxfs/xfs_alloc_btree.h | 7 +++
> fs/xfs/libxfs/xfs_ialloc_btree.c | 91 ++++++++++++++++++++++++++++++-----
> fs/xfs/libxfs/xfs_ialloc_btree.h | 6 ++
> fs/xfs/libxfs/xfs_refcount_btree.c | 70 +++++++++++++++++++++++----
> fs/xfs/libxfs/xfs_refcount_btree.h | 7 +++
> fs/xfs/libxfs/xfs_rmap_btree.c | 67 ++++++++++++++++++++++----
> fs/xfs/libxfs/xfs_rmap_btree.h | 6 ++
> 8 files changed, 298 insertions(+), 49 deletions(-)
>
>
> diff --git a/fs/xfs/libxfs/xfs_alloc_btree.c b/fs/xfs/libxfs/xfs_alloc_btree.c
> index 2a94543857a1..c1b03f67afa0 100644
> --- a/fs/xfs/libxfs/xfs_alloc_btree.c
> +++ b/fs/xfs/libxfs/xfs_alloc_btree.c
...
> @@ -485,35 +516,67 @@ xfs_allocbt_init_cursor(
...
> +/* Create a free space btree cursor with a fake root for staging. */
> +struct xfs_btree_cur *
> +xfs_allocbt_stage_cursor(
> + struct xfs_mount *mp,
> + struct xfs_trans *tp,
> + struct xbtree_afakeroot *afake,
> + xfs_agnumber_t agno,
> + xfs_btnum_t btnum)
> +{
> + struct xfs_btree_cur *cur;
> + struct xfs_btree_ops *ops;
>
> + cur = xfs_allocbt_init_common(mp, tp, agno, btnum);
> + if (btnum == XFS_BTNUM_BNO)
> + xfs_btree_stage_afakeroot(cur, afake, &xfs_bnobt_ops, &ops);
> + else
> + xfs_btree_stage_afakeroot(cur, afake, &xfs_cntbt_ops, &ops);
FWIW, to this point it doesn't look like any caller of the above
function uses the ops output.
Also, any reason the original ->bc_ops can't be assigned by the common
init function and just copied/replaced by the staging helper (similar to
how the commit path frees and replaces the staging ops)?
Brian
> return cur;
> }
>
> +/*
> + * Install a new free space btree root. Caller is responsible for invalidating
> + * and freeing the old btree blocks.
> + */
> +void
> +xfs_allocbt_commit_staged_btree(
> + struct xfs_btree_cur *cur,
> + struct xfs_buf *agbp)
> +{
> + struct xfs_agf *agf = XFS_BUF_TO_AGF(agbp);
> + struct xbtree_afakeroot *afake = cur->bc_private.a.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);
> + xfs_alloc_log_agf(cur->bc_tp, agbp, XFS_AGF_ROOTS | XFS_AGF_LEVELS);
> +
> + if (cur->bc_btnum == XFS_BTNUM_BNO) {
> + xfs_btree_commit_afakeroot(cur, agbp, &xfs_bnobt_ops);
> + } else {
> + cur->bc_flags |= XFS_BTREE_LASTREC_UPDATE;
> + xfs_btree_commit_afakeroot(cur, agbp, &xfs_cntbt_ops);
> + }
> +}
> +
> /*
> * Calculate number of records in an alloc btree block.
> */
> diff --git a/fs/xfs/libxfs/xfs_alloc_btree.h b/fs/xfs/libxfs/xfs_alloc_btree.h
> index c9305ebb69f6..dde324609a89 100644
> --- a/fs/xfs/libxfs/xfs_alloc_btree.h
> +++ b/fs/xfs/libxfs/xfs_alloc_btree.h
> @@ -13,6 +13,7 @@
> struct xfs_buf;
> struct xfs_btree_cur;
> struct xfs_mount;
> +struct xbtree_afakeroot;
>
> /*
> * Btree block header size depends on a superblock flag.
> @@ -48,8 +49,14 @@ struct xfs_mount;
> extern struct xfs_btree_cur *xfs_allocbt_init_cursor(struct xfs_mount *,
> struct xfs_trans *, struct xfs_buf *,
> xfs_agnumber_t, xfs_btnum_t);
> +struct xfs_btree_cur *xfs_allocbt_stage_cursor(struct xfs_mount *mp,
> + struct xfs_trans *tp, struct xbtree_afakeroot *afake,
> + xfs_agnumber_t agno, xfs_btnum_t btnum);
> extern int xfs_allocbt_maxrecs(struct xfs_mount *, int, int);
> extern xfs_extlen_t xfs_allocbt_calc_size(struct xfs_mount *mp,
> unsigned long long len);
>
> +void xfs_allocbt_commit_staged_btree(struct xfs_btree_cur *cur,
> + struct xfs_buf *agbp);
> +
> #endif /* __XFS_ALLOC_BTREE_H__ */
> diff --git a/fs/xfs/libxfs/xfs_ialloc_btree.c b/fs/xfs/libxfs/xfs_ialloc_btree.c
> index b82992f795aa..f61d94daa0a1 100644
> --- a/fs/xfs/libxfs/xfs_ialloc_btree.c
> +++ b/fs/xfs/libxfs/xfs_ialloc_btree.c
> @@ -400,45 +400,108 @@ static const struct xfs_btree_ops xfs_finobt_ops = {
> };
>
> /*
> - * Allocate a new inode btree cursor.
> + * Initialize a new inode btree cursor.
> */
> -struct xfs_btree_cur * /* new inode btree cursor */
> -xfs_inobt_init_cursor(
> +static struct xfs_btree_cur *
> +xfs_inobt_init_common(
> struct xfs_mount *mp, /* file system mount point */
> struct xfs_trans *tp, /* transaction pointer */
> - struct xfs_buf *agbp, /* buffer for agi structure */
> xfs_agnumber_t agno, /* allocation group number */
> xfs_btnum_t btnum) /* ialloc or free ino btree */
> {
> - struct xfs_agi *agi = XFS_BUF_TO_AGI(agbp);
> struct xfs_btree_cur *cur;
>
> cur = kmem_zone_zalloc(xfs_btree_cur_zone, KM_NOFS);
> -
> cur->bc_tp = tp;
> cur->bc_mp = mp;
> cur->bc_btnum = btnum;
> - if (btnum == XFS_BTNUM_INO) {
> - cur->bc_nlevels = be32_to_cpu(agi->agi_level);
> - cur->bc_ops = &xfs_inobt_ops;
> + if (btnum == XFS_BTNUM_INO)
> cur->bc_statoff = XFS_STATS_CALC_INDEX(xs_ibt_2);
> - } else {
> - cur->bc_nlevels = be32_to_cpu(agi->agi_free_level);
> - cur->bc_ops = &xfs_finobt_ops;
> + else
> cur->bc_statoff = XFS_STATS_CALC_INDEX(xs_fibt_2);
> - }
>
> cur->bc_blocklog = mp->m_sb.sb_blocklog;
>
> if (xfs_sb_version_hascrc(&mp->m_sb))
> cur->bc_flags |= XFS_BTREE_CRC_BLOCKS;
>
> - cur->bc_private.a.agbp = agbp;
> cur->bc_private.a.agno = agno;
> + return cur;
> +}
>
> +/* Create an inode btree cursor. */
> +struct xfs_btree_cur *
> +xfs_inobt_init_cursor(
> + struct xfs_mount *mp,
> + struct xfs_trans *tp,
> + struct xfs_buf *agbp,
> + xfs_agnumber_t agno,
> + xfs_btnum_t btnum)
> +{
> + struct xfs_btree_cur *cur;
> + struct xfs_agi *agi = XFS_BUF_TO_AGI(agbp);
> +
> + cur = xfs_inobt_init_common(mp, tp, agno, btnum);
> + if (btnum == XFS_BTNUM_INO) {
> + cur->bc_nlevels = be32_to_cpu(agi->agi_level);
> + cur->bc_ops = &xfs_inobt_ops;
> + } else {
> + cur->bc_nlevels = be32_to_cpu(agi->agi_free_level);
> + cur->bc_ops = &xfs_finobt_ops;
> + }
> + cur->bc_private.a.agbp = agbp;
> + return cur;
> +}
> +
> +/* Create an inode btree cursor with a fake root for staging. */
> +struct xfs_btree_cur *
> +xfs_inobt_stage_cursor(
> + struct xfs_mount *mp,
> + struct xfs_trans *tp,
> + struct xbtree_afakeroot *afake,
> + xfs_agnumber_t agno,
> + xfs_btnum_t btnum)
> +{
> + struct xfs_btree_cur *cur;
> + struct xfs_btree_ops *ops;
> +
> + cur = xfs_inobt_init_common(mp, tp, agno, btnum);
> + if (btnum == XFS_BTNUM_INO)
> + xfs_btree_stage_afakeroot(cur, afake, &xfs_inobt_ops, &ops);
> + else
> + xfs_btree_stage_afakeroot(cur, afake, &xfs_finobt_ops, &ops);
> return cur;
> }
>
> +/*
> + * Install a new inobt btree root. Caller is responsible for invalidating
> + * and freeing the old btree blocks.
> + */
> +void
> +xfs_inobt_commit_staged_btree(
> + struct xfs_btree_cur *cur,
> + struct xfs_buf *agbp)
> +{
> + struct xfs_agi *agi = XFS_BUF_TO_AGI(agbp);
> + struct xbtree_afakeroot *afake = cur->bc_private.a.afake;
> +
> + ASSERT(cur->bc_flags & XFS_BTREE_STAGING);
> +
> + if (cur->bc_btnum == XFS_BTNUM_INO) {
> + agi->agi_root = cpu_to_be32(afake->af_root);
> + agi->agi_level = cpu_to_be32(afake->af_levels);
> + xfs_ialloc_log_agi(cur->bc_tp, agbp, XFS_AGI_ROOT |
> + XFS_AGI_LEVEL);
> + xfs_btree_commit_afakeroot(cur, agbp, &xfs_inobt_ops);
> + } else {
> + agi->agi_free_root = cpu_to_be32(afake->af_root);
> + agi->agi_free_level = cpu_to_be32(afake->af_levels);
> + xfs_ialloc_log_agi(cur->bc_tp, agbp, XFS_AGI_FREE_ROOT |
> + XFS_AGI_FREE_LEVEL);
> + xfs_btree_commit_afakeroot(cur, agbp, &xfs_finobt_ops);
> + }
> +}
> +
> /*
> * Calculate number of records in an inobt btree block.
> */
> diff --git a/fs/xfs/libxfs/xfs_ialloc_btree.h b/fs/xfs/libxfs/xfs_ialloc_btree.h
> index 951305ecaae1..9265b3e08c69 100644
> --- a/fs/xfs/libxfs/xfs_ialloc_btree.h
> +++ b/fs/xfs/libxfs/xfs_ialloc_btree.h
> @@ -48,6 +48,9 @@ struct xfs_mount;
> extern struct xfs_btree_cur *xfs_inobt_init_cursor(struct xfs_mount *,
> struct xfs_trans *, struct xfs_buf *, xfs_agnumber_t,
> xfs_btnum_t);
> +struct xfs_btree_cur *xfs_inobt_stage_cursor(struct xfs_mount *mp,
> + struct xfs_trans *tp, struct xbtree_afakeroot *afake,
> + xfs_agnumber_t agno, xfs_btnum_t btnum);
> extern int xfs_inobt_maxrecs(struct xfs_mount *, int, int);
>
> /* ir_holemask to inode allocation bitmap conversion */
> @@ -68,4 +71,7 @@ int xfs_inobt_cur(struct xfs_mount *mp, struct xfs_trans *tp,
> xfs_agnumber_t agno, xfs_btnum_t btnum,
> struct xfs_btree_cur **curpp, struct xfs_buf **agi_bpp);
>
> +void xfs_inobt_commit_staged_btree(struct xfs_btree_cur *cur,
> + struct xfs_buf *agbp);
> +
> #endif /* __XFS_IALLOC_BTREE_H__ */
> diff --git a/fs/xfs/libxfs/xfs_refcount_btree.c b/fs/xfs/libxfs/xfs_refcount_btree.c
> index 38529dbacd55..8bf6aeee8f92 100644
> --- a/fs/xfs/libxfs/xfs_refcount_btree.c
> +++ b/fs/xfs/libxfs/xfs_refcount_btree.c
> @@ -311,41 +311,91 @@ static const struct xfs_btree_ops xfs_refcountbt_ops = {
> };
>
> /*
> - * Allocate a new refcount btree cursor.
> + * Initialize a new refcount btree cursor.
> */
> -struct xfs_btree_cur *
> -xfs_refcountbt_init_cursor(
> +static struct xfs_btree_cur *
> +xfs_refcountbt_init_common(
> struct xfs_mount *mp,
> struct xfs_trans *tp,
> - struct xfs_buf *agbp,
> xfs_agnumber_t agno)
> {
> - struct xfs_agf *agf = XFS_BUF_TO_AGF(agbp);
> struct xfs_btree_cur *cur;
>
> ASSERT(agno != NULLAGNUMBER);
> ASSERT(agno < mp->m_sb.sb_agcount);
> - cur = kmem_zone_zalloc(xfs_btree_cur_zone, KM_NOFS);
>
> + cur = kmem_zone_zalloc(xfs_btree_cur_zone, KM_NOFS);
> cur->bc_tp = tp;
> cur->bc_mp = mp;
> cur->bc_btnum = XFS_BTNUM_REFC;
> cur->bc_blocklog = mp->m_sb.sb_blocklog;
> - cur->bc_ops = &xfs_refcountbt_ops;
> cur->bc_statoff = XFS_STATS_CALC_INDEX(xs_refcbt_2);
>
> - cur->bc_nlevels = be32_to_cpu(agf->agf_refcount_level);
> -
> - cur->bc_private.a.agbp = agbp;
> cur->bc_private.a.agno = agno;
> cur->bc_flags |= XFS_BTREE_CRC_BLOCKS;
>
> cur->bc_private.a.priv.refc.nr_ops = 0;
> cur->bc_private.a.priv.refc.shape_changes = 0;
> + return cur;
> +}
> +
> +/* Create a btree cursor. */
> +struct xfs_btree_cur *
> +xfs_refcountbt_init_cursor(
> + struct xfs_mount *mp,
> + struct xfs_trans *tp,
> + struct xfs_buf *agbp,
> + xfs_agnumber_t agno)
> +{
> + struct xfs_agf *agf = XFS_BUF_TO_AGF(agbp);
> + struct xfs_btree_cur *cur;
>
> + cur = xfs_refcountbt_init_common(mp, tp, agno);
> + cur->bc_nlevels = be32_to_cpu(agf->agf_refcount_level);
> + cur->bc_private.a.agbp = agbp;
> + cur->bc_ops = &xfs_refcountbt_ops;
> return cur;
> }
>
> +/* Create a btree cursor with a fake root for staging. */
> +struct xfs_btree_cur *
> +xfs_refcountbt_stage_cursor(
> + struct xfs_mount *mp,
> + struct xfs_trans *tp,
> + struct xbtree_afakeroot *afake,
> + xfs_agnumber_t agno)
> +{
> + struct xfs_btree_cur *cur;
> + struct xfs_btree_ops *ops;
> +
> + cur = xfs_refcountbt_init_common(mp, tp, agno);
> + xfs_btree_stage_afakeroot(cur, afake, &xfs_refcountbt_ops, &ops);
> + return cur;
> +}
> +
> +/*
> + * Swap in the new btree root. Once we pass this point the newly rebuilt btree
> + * is in place and we have to kill off all the old btree blocks.
> + */
> +void
> +xfs_refcountbt_commit_staged_btree(
> + struct xfs_btree_cur *cur,
> + struct xfs_buf *agbp)
> +{
> + struct xfs_agf *agf = XFS_BUF_TO_AGF(agbp);
> + struct xbtree_afakeroot *afake = cur->bc_private.a.afake;
> +
> + ASSERT(cur->bc_flags & XFS_BTREE_STAGING);
> +
> + agf->agf_refcount_root = cpu_to_be32(afake->af_root);
> + agf->agf_refcount_level = cpu_to_be32(afake->af_levels);
> + agf->agf_refcount_blocks = cpu_to_be32(afake->af_blocks);
> + xfs_alloc_log_agf(cur->bc_tp, agbp, XFS_AGF_REFCOUNT_BLOCKS |
> + XFS_AGF_REFCOUNT_ROOT |
> + XFS_AGF_REFCOUNT_LEVEL);
> + xfs_btree_commit_afakeroot(cur, agbp, &xfs_refcountbt_ops);
> +}
> +
> /*
> * Calculate the number of records in a refcount btree block.
> */
> diff --git a/fs/xfs/libxfs/xfs_refcount_btree.h b/fs/xfs/libxfs/xfs_refcount_btree.h
> index ba416f71c824..978b714be9f4 100644
> --- a/fs/xfs/libxfs/xfs_refcount_btree.h
> +++ b/fs/xfs/libxfs/xfs_refcount_btree.h
> @@ -13,6 +13,7 @@
> struct xfs_buf;
> struct xfs_btree_cur;
> struct xfs_mount;
> +struct xbtree_afakeroot;
>
> /*
> * Btree block header size
> @@ -46,6 +47,9 @@ struct xfs_mount;
> extern struct xfs_btree_cur *xfs_refcountbt_init_cursor(struct xfs_mount *mp,
> struct xfs_trans *tp, struct xfs_buf *agbp,
> xfs_agnumber_t agno);
> +struct xfs_btree_cur *xfs_refcountbt_stage_cursor(struct xfs_mount *mp,
> + struct xfs_trans *tp, struct xbtree_afakeroot *afake,
> + xfs_agnumber_t agno);
> extern int xfs_refcountbt_maxrecs(int blocklen, bool leaf);
> extern void xfs_refcountbt_compute_maxlevels(struct xfs_mount *mp);
>
> @@ -58,4 +62,7 @@ extern int xfs_refcountbt_calc_reserves(struct xfs_mount *mp,
> struct xfs_trans *tp, xfs_agnumber_t agno, xfs_extlen_t *ask,
> xfs_extlen_t *used);
>
> +void xfs_refcountbt_commit_staged_btree(struct xfs_btree_cur *cur,
> + struct xfs_buf *agbp);
> +
> #endif /* __XFS_REFCOUNT_BTREE_H__ */
> diff --git a/fs/xfs/libxfs/xfs_rmap_btree.c b/fs/xfs/libxfs/xfs_rmap_btree.c
> index fc78efa52c94..8e05576dcaa1 100644
> --- a/fs/xfs/libxfs/xfs_rmap_btree.c
> +++ b/fs/xfs/libxfs/xfs_rmap_btree.c
> @@ -448,17 +448,12 @@ static const struct xfs_btree_ops xfs_rmapbt_ops = {
> .recs_inorder = xfs_rmapbt_recs_inorder,
> };
>
> -/*
> - * Allocate a new allocation btree cursor.
> - */
> -struct xfs_btree_cur *
> -xfs_rmapbt_init_cursor(
> +static struct xfs_btree_cur *
> +xfs_rmapbt_init_common(
> struct xfs_mount *mp,
> struct xfs_trans *tp,
> - struct xfs_buf *agbp,
> xfs_agnumber_t agno)
> {
> - struct xfs_agf *agf = XFS_BUF_TO_AGF(agbp);
> struct xfs_btree_cur *cur;
>
> cur = kmem_zone_zalloc(xfs_btree_cur_zone, KM_NOFS);
> @@ -468,16 +463,68 @@ xfs_rmapbt_init_cursor(
> cur->bc_btnum = XFS_BTNUM_RMAP;
> cur->bc_flags = XFS_BTREE_CRC_BLOCKS | XFS_BTREE_OVERLAPPING;
> cur->bc_blocklog = mp->m_sb.sb_blocklog;
> - cur->bc_ops = &xfs_rmapbt_ops;
> - cur->bc_nlevels = be32_to_cpu(agf->agf_levels[XFS_BTNUM_RMAP]);
> cur->bc_statoff = XFS_STATS_CALC_INDEX(xs_rmap_2);
> + cur->bc_private.a.agno = agno;
> +
> + 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,
> + xfs_agnumber_t agno)
> +{
> + struct xfs_agf *agf = XFS_BUF_TO_AGF(agbp);
> + struct xfs_btree_cur *cur;
>
> + cur = xfs_rmapbt_init_common(mp, tp, agno);
> + cur->bc_ops = &xfs_rmapbt_ops;
> + cur->bc_nlevels = be32_to_cpu(agf->agf_levels[XFS_BTNUM_RMAP]);
> cur->bc_private.a.agbp = agbp;
> - cur->bc_private.a.agno = agno;
> + 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 xfs_trans *tp,
> + struct xbtree_afakeroot *afake,
> + xfs_agnumber_t agno)
> +{
> + struct xfs_btree_cur *cur;
> + struct xfs_btree_ops *ops;
>
> + cur = xfs_rmapbt_init_common(mp, tp, agno);
> + xfs_btree_stage_afakeroot(cur, afake, &xfs_rmapbt_ops, &ops);
> 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_buf *agbp)
> +{
> + struct xfs_agf *agf = XFS_BUF_TO_AGF(agbp);
> + struct xbtree_afakeroot *afake = cur->bc_private.a.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(cur->bc_tp, agbp, XFS_AGF_ROOTS | XFS_AGF_LEVELS |
> + XFS_AGF_RMAP_BLOCKS);
> + xfs_btree_commit_afakeroot(cur, agbp, &xfs_rmapbt_ops);
> +}
> +
> /*
> * Calculate number of records in an rmap btree block.
> */
> diff --git a/fs/xfs/libxfs/xfs_rmap_btree.h b/fs/xfs/libxfs/xfs_rmap_btree.h
> index 820d668b063d..c6785c7851a8 100644
> --- a/fs/xfs/libxfs/xfs_rmap_btree.h
> +++ b/fs/xfs/libxfs/xfs_rmap_btree.h
> @@ -9,6 +9,7 @@
> struct xfs_buf;
> struct xfs_btree_cur;
> struct xfs_mount;
> +struct xbtree_afakeroot;
>
> /* rmaps only exist on crc enabled filesystems */
> #define XFS_RMAP_BLOCK_LEN XFS_BTREE_SBLOCK_CRC_LEN
> @@ -43,6 +44,11 @@ struct xfs_mount;
> struct xfs_btree_cur *xfs_rmapbt_init_cursor(struct xfs_mount *mp,
> struct xfs_trans *tp, struct xfs_buf *bp,
> xfs_agnumber_t agno);
> +struct xfs_btree_cur *xfs_rmapbt_stage_cursor(struct xfs_mount *mp,
> + struct xfs_trans *tp, struct xbtree_afakeroot *afake,
> + xfs_agnumber_t agno);
> +void xfs_rmapbt_commit_staged_btree(struct xfs_btree_cur *cur,
> + struct xfs_buf *agbp);
> int xfs_rmapbt_maxrecs(int blocklen, int leaf);
> extern void xfs_rmapbt_compute_maxlevels(struct xfs_mount *mp);
>
>
