bcachefs: Split out bpos_cmp() and bkey_cmp()

With snapshots, we're going to need to differentiate between comparisons
that should and shouldn't include the snapshot field. bpos_cmp is now
the comparison function that does include the snapshot field, used by
core btree code.

Upper level filesystem code generally does _not_ want to compare against
the snapshot field - that code wants keys to compare as equal even when
one of them is in an ancestor snapshot.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

1 files changed, 18 insertions, 0 deletions

diff --git a/fs/bcachefs/extents.h b/fs/bcachefs/extents.h
index c8069dfb90ff..ccee43a2019d 100644
--- a/fs/bcachefs/extents.h
+++ b/fs/bcachefs/extents.h
@@ -582,6 +582,24 @@ void bch2_ptr_swab(struct bkey_s);
 
 /* Generic extent code: */
 
+enum bch_extent_overlap {
+	BCH_EXTENT_OVERLAP_ALL		= 0,
+	BCH_EXTENT_OVERLAP_BACK		= 1,
+	BCH_EXTENT_OVERLAP_FRONT	= 2,
+	BCH_EXTENT_OVERLAP_MIDDLE	= 3,
+};
+
+/* Returns how k overlaps with m */
+static inline enum bch_extent_overlap bch2_extent_overlap(const struct bkey *k,
+							  const struct bkey *m)
+{
+	int cmp1 = bkey_cmp(k->p, m->p) < 0;
+	int cmp2 = bkey_cmp(bkey_start_pos(k),
+			    bkey_start_pos(m)) > 0;
+
+	return (cmp1 << 1) + cmp2;
+}
+
 int bch2_cut_front_s(struct bpos, struct bkey_s);
 int bch2_cut_back_s(struct bpos, struct bkey_s);