| Message ID | 147216792896.867.711816517859232858.stgit@birch.djwong.org (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
On Thu, Aug 25, 2016 at 04:32:09PM -0700, Darrick J. Wong wrote: > Create a helper to generate AG btree height calculator functions. > This will be used (much) later when we get to the refcount btree. > > v2: Use a helper function instead of a macro. > v3: We can (theoretically) store more than 2^32 records in a btree, so > widen the fields to accept that. > v4: Don't modify xfs_bmap_worst_indlen; the purpose of /that/ function > is to estimate the worst-case number of blocks needed for a bmbt > expansion, not to calculate the space required to store nr records. > v5: More minor tweaks to the loop control; move down to reflink patches. This should move down below the "---" line. Otherwise the patch looks fine: Reviewed-by: Christoph Hellwig <hch@lst.de>
diff --git a/fs/xfs/libxfs/xfs_btree.c b/fs/xfs/libxfs/xfs_btree.c index d1155ca..1bc483b 100644 --- a/fs/xfs/libxfs/xfs_btree.c +++ b/fs/xfs/libxfs/xfs_btree.c @@ -4801,3 +4801,27 @@ xfs_btree_query_range( return xfs_btree_overlapped_query_range(cur, &low_key, &high_key, fn, priv); } + +/* + * Calculate the number of blocks needed to store a given number of records + * in a short-format (per-AG metadata) btree. + */ +xfs_extlen_t +xfs_btree_calc_size( + struct xfs_mount *mp, + uint *limits, + unsigned long long len) +{ + int level; + int maxrecs; + xfs_extlen_t rval; + + maxrecs = limits[0]; + for (level = 0, rval = 0; len > 1; level++) { + len += maxrecs - 1; + do_div(len, maxrecs); + maxrecs = limits[1]; + rval += len; + } + return rval; +} diff --git a/fs/xfs/libxfs/xfs_btree.h b/fs/xfs/libxfs/xfs_btree.h index 870a5ab..607463a 100644 --- a/fs/xfs/libxfs/xfs_btree.h +++ b/fs/xfs/libxfs/xfs_btree.h @@ -501,6 +501,8 @@ bool xfs_btree_sblock_v5hdr_verify(struct xfs_buf *bp); bool xfs_btree_sblock_verify(struct xfs_buf *bp, unsigned int max_recs); uint xfs_btree_compute_maxlevels(struct xfs_mount *mp, uint *limits, unsigned long len); +xfs_extlen_t xfs_btree_calc_size(struct xfs_mount *mp, uint *limits, + unsigned long long len); /* return codes */ #define XFS_BTREE_QUERY_RANGE_CONTINUE 0 /* keep iterating */
Create a helper to generate AG btree height calculator functions. This will be used (much) later when we get to the refcount btree. v2: Use a helper function instead of a macro. v3: We can (theoretically) store more than 2^32 records in a btree, so widen the fields to accept that. v4: Don't modify xfs_bmap_worst_indlen; the purpose of /that/ function is to estimate the worst-case number of blocks needed for a bmbt expansion, not to calculate the space required to store nr records. v5: More minor tweaks to the loop control; move down to reflink patches. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> --- fs/xfs/libxfs/xfs_btree.c | 24 ++++++++++++++++++++++++ fs/xfs/libxfs/xfs_btree.h | 2 ++ 2 files changed, 26 insertions(+)