bcachefs: Subvolumes, snapshots

This patch adds subvolume.c - support for the subvolumes and snapshots
btrees and related data types and on disk data structures. The next
patches will start hooking up this new code to existing code.

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

1 files changed, 77 insertions, 0 deletions

diff --git a/fs/bcachefs/subvolume.h b/fs/bcachefs/subvolume.h
new file mode 100644
index 000000000000..cea4c665af32
--- /dev/null
+++ b/fs/bcachefs/subvolume.h
@@ -0,0 +1,77 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _BCACHEFS_SUBVOLUME_H
+#define _BCACHEFS_SUBVOLUME_H
+
+void bch2_snapshot_to_text(struct printbuf *, struct bch_fs *, struct bkey_s_c);
+const char *bch2_snapshot_invalid(const struct bch_fs *, struct bkey_s_c);
+
+#define bch2_bkey_ops_snapshot (struct bkey_ops) {		\
+	.key_invalid	= bch2_snapshot_invalid,		\
+	.val_to_text	= bch2_snapshot_to_text,		\
+}
+
+int bch2_mark_snapshot(struct bch_fs *, struct bkey_s_c,
+		       struct bkey_s_c, u64, unsigned);
+
+static inline struct snapshot_t *snapshot_t(struct bch_fs *c, u32 id)
+{
+	return genradix_ptr(&c->snapshots, U32_MAX - id);
+}
+
+static inline u32 bch2_snapshot_parent(struct bch_fs *c, u32 id)
+{
+	return snapshot_t(c, id)->parent;
+}
+
+static inline u32 bch2_snapshot_internal_node(struct bch_fs *c, u32 id)
+{
+	struct snapshot_t *s = snapshot_t(c, id);
+
+	return s->children[0] || s->children[1];
+}
+
+static inline u32 bch2_snapshot_sibling(struct bch_fs *c, u32 id)
+{
+	struct snapshot_t *s;
+	u32 parent = bch2_snapshot_parent(c, id);
+
+	if (!parent)
+		return 0;
+
+	s = snapshot_t(c, bch2_snapshot_parent(c, id));
+	if (id == s->children[0])
+		return s->children[1];
+	if (id == s->children[1])
+		return s->children[0];
+	return 0;
+}
+
+static inline bool bch2_snapshot_is_ancestor(struct bch_fs *c, u32 id, u32 ancestor)
+{
+	while (id && id < ancestor)
+		id = bch2_snapshot_parent(c, id);
+
+	return id == ancestor;
+}
+
+int bch2_fs_snapshots_check(struct bch_fs *);
+void bch2_fs_snapshots_exit(struct bch_fs *);
+int bch2_fs_snapshots_start(struct bch_fs *);
+
+const char *bch2_subvolume_invalid(const struct bch_fs *, struct bkey_s_c);
+void bch2_subvolume_to_text(struct printbuf *, struct bch_fs *, struct bkey_s_c);
+
+#define bch2_bkey_ops_subvolume (struct bkey_ops) {		\
+	.key_invalid	= bch2_subvolume_invalid,		\
+	.val_to_text	= bch2_subvolume_to_text,		\
+}
+
+int bch2_subvolume_get_snapshot(struct btree_trans *, u32, u32 *);
+
+int bch2_subvolume_delete(struct btree_trans *, u32, int);
+int bch2_subvolume_create(struct btree_trans *, u64, u32,
+			  u32 *, u32 *, bool);
+
+int bch2_fs_subvolumes_init(struct bch_fs *);
+
+#endif /* _BCACHEFS_SUBVOLUME_H */