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Re: [PATCH 032/119] xfs: add rmap btree operations

To: "Darrick J. Wong" <darrick.wong@xxxxxxxxxx>
Subject: Re: [PATCH 032/119] xfs: add rmap btree operations
From: Brian Foster <bfoster@xxxxxxxxxx>
Date: Fri, 8 Jul 2016 14:33:47 -0400
Cc: david@xxxxxxxxxxxxx, linux-fsdevel@xxxxxxxxxxxxxxx, vishal.l.verma@xxxxxxxxx, Dave Chinner <dchinner@xxxxxxxxxx>, xfs@xxxxxxxxxxx
Delivered-to: xfs@xxxxxxxxxxx
In-reply-to: <146612647771.12839.2301418036042118299.stgit@xxxxxxxxxxxxxxxx>
References: <146612627129.12839.3827886950949809165.stgit@xxxxxxxxxxxxxxxx> <146612647771.12839.2301418036042118299.stgit@xxxxxxxxxxxxxxxx>
User-agent: Mutt/1.6.1 (2016-04-27)
On Thu, Jun 16, 2016 at 06:21:17PM -0700, Darrick J. Wong wrote:
> From: Dave Chinner <dchinner@xxxxxxxxxx>
> 
> Implement the generic btree operations needed to manipulate rmap
> btree blocks. This is very similar to the per-ag freespace btree
> implementation, and uses the AGFL for allocation and freeing of
> blocks.
> 
> Adapt the rmap btree to store owner offsets within each rmap record,
> and to handle the primary key being redefined as the tuple
> [agblk, owner, offset].  The expansion of the primary key is crucial
> to allowing multiple owners per extent.
> 
> [darrick: adapt the btree ops to deal with offsets]
> [darrick: remove init_rec_from_key]
> [darrick: move unwritten bit to rm_offset]
> 
> Signed-off-by: Dave Chinner <dchinner@xxxxxxxxxx>
> Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
> Reviewed-by: Dave Chinner <dchinner@xxxxxxxxxx>
> Signed-off-by: Dave Chinner <david@xxxxxxxxxxxxx>
> ---
>  fs/xfs/libxfs/xfs_btree.h      |    1 
>  fs/xfs/libxfs/xfs_rmap.c       |   96 ++++++++++++++++
>  fs/xfs/libxfs/xfs_rmap_btree.c |  243 
> ++++++++++++++++++++++++++++++++++++++++
>  fs/xfs/libxfs/xfs_rmap_btree.h |    9 +
>  fs/xfs/xfs_trace.h             |    3 
>  5 files changed, 352 insertions(+)
> 
> 
> diff --git a/fs/xfs/libxfs/xfs_btree.h b/fs/xfs/libxfs/xfs_btree.h
> index 90ea2a7..9963c48 100644
> --- a/fs/xfs/libxfs/xfs_btree.h
> +++ b/fs/xfs/libxfs/xfs_btree.h
> @@ -216,6 +216,7 @@ union xfs_btree_irec {
>       xfs_alloc_rec_incore_t          a;
>       xfs_bmbt_irec_t                 b;
>       xfs_inobt_rec_incore_t          i;
> +     struct xfs_rmap_irec            r;
>  };
>  
>  /*
> diff --git a/fs/xfs/libxfs/xfs_rmap.c b/fs/xfs/libxfs/xfs_rmap.c
> index d1fd471..c6a5a0b 100644
> --- a/fs/xfs/libxfs/xfs_rmap.c
> +++ b/fs/xfs/libxfs/xfs_rmap.c
> @@ -37,6 +37,102 @@
>  #include "xfs_error.h"
>  #include "xfs_extent_busy.h"
>  
...
> +/*
> + * Update the record referred to by cur to the value given
> + * by [bno, len, owner, offset].
> + * This either works (return 0) or gets an EFSCORRUPTED error.
> + */
> +STATIC int
> +xfs_rmap_update(

This throws an unused warning, but I assume it will be used later.

> +     struct xfs_btree_cur    *cur,
> +     struct xfs_rmap_irec    *irec)
> +{
> +     union xfs_btree_rec     rec;
> +
> +     rec.rmap.rm_startblock = cpu_to_be32(irec->rm_startblock);
> +     rec.rmap.rm_blockcount = cpu_to_be32(irec->rm_blockcount);
> +     rec.rmap.rm_owner = cpu_to_be64(irec->rm_owner);
> +     rec.rmap.rm_offset = cpu_to_be64(
> +                     xfs_rmap_irec_offset_pack(irec));
> +     return xfs_btree_update(cur, &rec);
> +}
> +
...
>  int
>  xfs_rmap_free(
>       struct xfs_trans        *tp,
> diff --git a/fs/xfs/libxfs/xfs_rmap_btree.c b/fs/xfs/libxfs/xfs_rmap_btree.c
> index 7a35c78..c50c725 100644
> --- a/fs/xfs/libxfs/xfs_rmap_btree.c
> +++ b/fs/xfs/libxfs/xfs_rmap_btree.c
...
> @@ -43,6 +68,173 @@ xfs_rmapbt_dup_cursor(
>                       cur->bc_private.a.agbp, cur->bc_private.a.agno);
>  }
>  
> +STATIC void
> +xfs_rmapbt_set_root(
> +     struct xfs_btree_cur    *cur,
> +     union xfs_btree_ptr     *ptr,
> +     int                     inc)
> +{
> +     struct xfs_buf          *agbp = cur->bc_private.a.agbp;
> +     struct xfs_agf          *agf = XFS_BUF_TO_AGF(agbp);
> +     xfs_agnumber_t          seqno = be32_to_cpu(agf->agf_seqno);
> +     int                     btnum = cur->bc_btnum;
> +     struct xfs_perag        *pag = xfs_perag_get(cur->bc_mp, seqno);
> +
> +     ASSERT(ptr->s != 0);
> +
> +     agf->agf_roots[btnum] = ptr->s;
> +     be32_add_cpu(&agf->agf_levels[btnum], inc);
> +     pag->pagf_levels[btnum] += inc;
> +     xfs_perag_put(pag);
> +
> +     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,
> +     union xfs_btree_ptr     *start,
> +     union xfs_btree_ptr     *new,
> +     int                     *stat)
> +{
> +     int                     error;
> +     xfs_agblock_t           bno;
> +
> +     XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
> +
> +     /* Allocate the new block from the freelist. If we can't, give up.  */
> +     error = xfs_alloc_get_freelist(cur->bc_tp, cur->bc_private.a.agbp,
> +                                    &bno, 1);
> +     if (error) {
> +             XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
> +             return error;
> +     }
> +
> +     trace_xfs_rmapbt_alloc_block(cur->bc_mp, cur->bc_private.a.agno,
> +                     bno, 1);
> +     if (bno == NULLAGBLOCK) {
> +             XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
> +             *stat = 0;
> +             return 0;
> +     }
> +
> +     xfs_extent_busy_reuse(cur->bc_mp, cur->bc_private.a.agno, bno, 1,
> +                     false);
> +
> +     xfs_trans_agbtree_delta(cur->bc_tp, 1);
> +     new->s = cpu_to_be32(bno);
> +
> +     XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
> +     *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_private.a.agbp;
> +     struct xfs_agf          *agf = XFS_BUF_TO_AGF(agbp);
> +     xfs_agblock_t           bno;
> +     int                     error;
> +
> +     bno = xfs_daddr_to_agbno(cur->bc_mp, XFS_BUF_ADDR(bp));
> +     trace_xfs_rmapbt_free_block(cur->bc_mp, cur->bc_private.a.agno,
> +                     bno, 1);
> +     error = xfs_alloc_put_freelist(cur->bc_tp, agbp, NULL, bno, 1);
> +     if (error)
> +             return error;
> +
> +     xfs_extent_busy_insert(cur->bc_tp, be32_to_cpu(agf->agf_seqno), bno, 1,
> +                           XFS_EXTENT_BUSY_SKIP_DISCARD);
> +     xfs_trans_agbtree_delta(cur->bc_tp, -1);
> +
> +     xfs_trans_binval(cur->bc_tp, bp);

This is handled in the generic btree code.

> +     return 0;
> +}
> +
...
> @@ -117,12 +309,63 @@ const struct xfs_buf_ops xfs_rmapbt_buf_ops = {
>       .verify_write           = xfs_rmapbt_write_verify,
>  };
>  
> +#if defined(DEBUG) || defined(XFS_WARN)
> +STATIC int
> +xfs_rmapbt_keys_inorder(
> +     struct xfs_btree_cur    *cur,
> +     union xfs_btree_key     *k1,
> +     union xfs_btree_key     *k2)
> +{
> +     if (be32_to_cpu(k1->rmap.rm_startblock) <
> +         be32_to_cpu(k2->rmap.rm_startblock))
> +             return 1;
> +     if (be64_to_cpu(k1->rmap.rm_owner) <
> +         be64_to_cpu(k2->rmap.rm_owner))
> +             return 1;
> +     if (XFS_RMAP_OFF(be64_to_cpu(k1->rmap.rm_offset)) <=
> +         XFS_RMAP_OFF(be64_to_cpu(k2->rmap.rm_offset)))
> +             return 1;
> +     return 0;

I might just not be familiar enough with the rmapbt ordering rules, but
this doesn't look right. If the rm_startblock values are out of order
(k1 startblock > k2 startblock), but either of the owner or offset
values are in-order, then we call the keys in order. Is that intentional
or should (k1->rmap.rm_startblock > k2->rmap.rm_startblock) always
return 0?

> +}
> +
> +STATIC int
> +xfs_rmapbt_recs_inorder(
> +     struct xfs_btree_cur    *cur,
> +     union xfs_btree_rec     *r1,
> +     union xfs_btree_rec     *r2)
> +{
> +     if (be32_to_cpu(r1->rmap.rm_startblock) <
> +         be32_to_cpu(r2->rmap.rm_startblock))
> +             return 1;
> +     if (XFS_RMAP_OFF(be64_to_cpu(r1->rmap.rm_offset)) <
> +         XFS_RMAP_OFF(be64_to_cpu(r2->rmap.rm_offset)))
> +             return 1;
> +     if (be64_to_cpu(r1->rmap.rm_owner) <=
> +         be64_to_cpu(r2->rmap.rm_owner))
> +             return 1;
> +     return 0;
> +}

Same question here.

Brian

> +#endif       /* DEBUG */
> +
>  static const struct xfs_btree_ops xfs_rmapbt_ops = {
>       .rec_len                = sizeof(struct xfs_rmap_rec),
>       .key_len                = 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_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,
> +#if defined(DEBUG) || defined(XFS_WARN)
> +     .keys_inorder           = xfs_rmapbt_keys_inorder,
> +     .recs_inorder           = xfs_rmapbt_recs_inorder,
> +#endif
>  };
>  
>  /*
> diff --git a/fs/xfs/libxfs/xfs_rmap_btree.h b/fs/xfs/libxfs/xfs_rmap_btree.h
> index 462767f..17fa383 100644
> --- a/fs/xfs/libxfs/xfs_rmap_btree.h
> +++ b/fs/xfs/libxfs/xfs_rmap_btree.h
> @@ -52,6 +52,15 @@ struct xfs_btree_cur *xfs_rmapbt_init_cursor(struct 
> xfs_mount *mp,
>  int xfs_rmapbt_maxrecs(struct xfs_mount *mp, int blocklen, int leaf);
>  extern void xfs_rmapbt_compute_maxlevels(struct xfs_mount *mp);
>  
> +int xfs_rmap_lookup_le(struct xfs_btree_cur *cur, xfs_agblock_t bno,
> +             xfs_extlen_t len, uint64_t owner, uint64_t offset,
> +             unsigned int flags, int *stat);
> +int xfs_rmap_lookup_eq(struct xfs_btree_cur *cur, xfs_agblock_t bno,
> +             xfs_extlen_t len, uint64_t owner, uint64_t offset,
> +             unsigned int flags, int *stat);
> +int xfs_rmap_get_rec(struct xfs_btree_cur *cur, struct xfs_rmap_irec *irec,
> +             int *stat);
> +
>  int xfs_rmap_alloc(struct xfs_trans *tp, struct xfs_buf *agbp,
>                  xfs_agnumber_t agno, xfs_agblock_t bno, xfs_extlen_t len,
>                  struct xfs_owner_info *oinfo);
> diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h
> index b4ee9c8..28bd991 100644
> --- a/fs/xfs/xfs_trace.h
> +++ b/fs/xfs/xfs_trace.h
> @@ -2470,6 +2470,9 @@ DEFINE_RMAP_EVENT(xfs_rmap_alloc_extent);
>  DEFINE_RMAP_EVENT(xfs_rmap_alloc_extent_done);
>  DEFINE_RMAP_EVENT(xfs_rmap_alloc_extent_error);
>  
> +DEFINE_BUSY_EVENT(xfs_rmapbt_alloc_block);
> +DEFINE_BUSY_EVENT(xfs_rmapbt_free_block);
> +
>  #endif /* _TRACE_XFS_H */
>  
>  #undef TRACE_INCLUDE_PATH
> 
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