| Message ID | 146612633632.12839.13314497569643567486.stgit@birch.djwong.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Thu, Jun 16, 2016 at 06:18:56PM -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. > > Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> > --- I think this one should probably be pushed out to where it is used (easier to review with an example imo). I don't see it used anywhere up through the rmapbt stuff, anyways... > fs/xfs/libxfs/xfs_btree.c | 27 +++++++++++++++++++++++++++ > fs/xfs/libxfs/xfs_btree.h | 3 +++ > 2 files changed, 30 insertions(+) > > > diff --git a/fs/xfs/libxfs/xfs_btree.c b/fs/xfs/libxfs/xfs_btree.c > index 105979d..5eb4e40 100644 > --- a/fs/xfs/libxfs/xfs_btree.c > +++ b/fs/xfs/libxfs/xfs_btree.c > @@ -4156,3 +4156,30 @@ xfs_btree_sblock_verify( > > return true; > } > + > +/* > + * 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 > 0; level++) { len is unsigned, so len > 0 is kind of pointless. Perhaps check len > 1 and kill the check in the loop? Brian > + len += maxrecs - 1; > + do_div(len, maxrecs); > + rval += len; > + if (len == 1) > + return rval; > + if (level == 0) > + maxrecs = limits[1]; > + } > + return rval; > +} > diff --git a/fs/xfs/libxfs/xfs_btree.h b/fs/xfs/libxfs/xfs_btree.h > index 9a88839..b330f19 100644 > --- a/fs/xfs/libxfs/xfs_btree.h > +++ b/fs/xfs/libxfs/xfs_btree.h > @@ -475,4 +475,7 @@ static inline int xfs_btree_get_level(struct xfs_btree_block *block) > bool xfs_btree_sblock_v5hdr_verify(struct xfs_buf *bp); > bool xfs_btree_sblock_verify(struct xfs_buf *bp, unsigned int max_recs); > > +xfs_extlen_t xfs_btree_calc_size(struct xfs_mount *mp, uint *limits, > + unsigned long long len); > + > #endif /* __XFS_BTREE_H__ */ > > _______________________________________________ > xfs mailing list > xfs@oss.sgi.com > http://oss.sgi.com/mailman/listinfo/xfs -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Mon, Jun 20, 2016 at 10:31:49AM -0400, Brian Foster wrote: > On Thu, Jun 16, 2016 at 06:18:56PM -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. > > > > Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> > > --- > > I think this one should probably be pushed out to where it is used > (easier to review with an example imo). I don't see it used anywhere up > through the rmapbt stuff, anyways... Oh, heh, you're right. At one point I was using it for the rmapbt, but nowadays it's only used for per-AG reservations (reflink+rmap) as you point out, so it could move. > > > fs/xfs/libxfs/xfs_btree.c | 27 +++++++++++++++++++++++++++ > > fs/xfs/libxfs/xfs_btree.h | 3 +++ > > 2 files changed, 30 insertions(+) > > > > > > diff --git a/fs/xfs/libxfs/xfs_btree.c b/fs/xfs/libxfs/xfs_btree.c > > index 105979d..5eb4e40 100644 > > --- a/fs/xfs/libxfs/xfs_btree.c > > +++ b/fs/xfs/libxfs/xfs_btree.c > > @@ -4156,3 +4156,30 @@ xfs_btree_sblock_verify( > > > > return true; > > } > > + > > +/* > > + * 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 > 0; level++) { > > len is unsigned, so len > 0 is kind of pointless. Perhaps check len > 1 > and kill the check in the loop? Yup. Thank you for pointing that out. --D > > Brian > > > + len += maxrecs - 1; > > + do_div(len, maxrecs); > > + rval += len; > > + if (len == 1) > > + return rval; > > + if (level == 0) > > + maxrecs = limits[1]; > > + } > > + return rval; > > +} > > diff --git a/fs/xfs/libxfs/xfs_btree.h b/fs/xfs/libxfs/xfs_btree.h > > index 9a88839..b330f19 100644 > > --- a/fs/xfs/libxfs/xfs_btree.h > > +++ b/fs/xfs/libxfs/xfs_btree.h > > @@ -475,4 +475,7 @@ static inline int xfs_btree_get_level(struct xfs_btree_block *block) > > bool xfs_btree_sblock_v5hdr_verify(struct xfs_buf *bp); > > bool xfs_btree_sblock_verify(struct xfs_buf *bp, unsigned int max_recs); > > > > +xfs_extlen_t xfs_btree_calc_size(struct xfs_mount *mp, uint *limits, > > + unsigned long long len); > > + > > #endif /* __XFS_BTREE_H__ */ > > > > _______________________________________________ > > xfs mailing list > > xfs@oss.sgi.com > > http://oss.sgi.com/mailman/listinfo/xfs -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/fs/xfs/libxfs/xfs_btree.c b/fs/xfs/libxfs/xfs_btree.c index 105979d..5eb4e40 100644 --- a/fs/xfs/libxfs/xfs_btree.c +++ b/fs/xfs/libxfs/xfs_btree.c @@ -4156,3 +4156,30 @@ xfs_btree_sblock_verify( return true; } + +/* + * 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 > 0; level++) { + len += maxrecs - 1; + do_div(len, maxrecs); + rval += len; + if (len == 1) + return rval; + if (level == 0) + maxrecs = limits[1]; + } + return rval; +} diff --git a/fs/xfs/libxfs/xfs_btree.h b/fs/xfs/libxfs/xfs_btree.h index 9a88839..b330f19 100644 --- a/fs/xfs/libxfs/xfs_btree.h +++ b/fs/xfs/libxfs/xfs_btree.h @@ -475,4 +475,7 @@ static inline int xfs_btree_get_level(struct xfs_btree_block *block) bool xfs_btree_sblock_v5hdr_verify(struct xfs_buf *bp); bool xfs_btree_sblock_verify(struct xfs_buf *bp, unsigned int max_recs); +xfs_extlen_t xfs_btree_calc_size(struct xfs_mount *mp, uint *limits, + unsigned long long len); + #endif /* __XFS_BTREE_H__ */
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. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> --- fs/xfs/libxfs/xfs_btree.c | 27 +++++++++++++++++++++++++++ fs/xfs/libxfs/xfs_btree.h | 3 +++ 2 files changed, 30 insertions(+) -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html