bcachefs: Freespace, need_discard btrees

This adds two new btrees for the upcoming allocator rewrite: an extents
btree of free buckets, and a btree for buckets awaiting discards.

We also add a new trigger for alloc keys to keep the new btrees up to
date, and a compatibility path to initialize them on existing
filesystems.

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

1 files changed, 53 insertions, 0 deletions

diff --git a/fs/bcachefs/alloc_background.h b/fs/bcachefs/alloc_background.h
index b66c8cf0341e..8de109674f0f 100644
--- a/fs/bcachefs/alloc_background.h
+++ b/fs/bcachefs/alloc_background.h
@@ -13,6 +13,51 @@ extern const char * const bch2_allocator_states[];
 /* How out of date a pointer gen is allowed to be: */
 #define BUCKET_GC_GEN_MAX	96U
 
+static inline u8 alloc_gc_gen(struct bch_alloc_v4 a)
+{
+	return a.gen - a.oldest_gen;
+}
+
+enum bucket_state {
+	BUCKET_free,
+	BUCKET_need_gc_gens,
+	BUCKET_need_discard,
+	BUCKET_cached,
+	BUCKET_dirty,
+};
+
+extern const char * const bch2_bucket_states[];
+
+static inline enum bucket_state bucket_state(struct bch_alloc_v4 a)
+{
+	if (a.dirty_sectors || a.stripe)
+		return BUCKET_dirty;
+	if (a.cached_sectors)
+		return BUCKET_cached;
+	BUG_ON(a.data_type);
+	if (BCH_ALLOC_V4_NEED_DISCARD(&a))
+		return BUCKET_need_discard;
+	if (alloc_gc_gen(a) >= BUCKET_GC_GEN_MAX)
+		return BUCKET_need_gc_gens;
+	return BUCKET_free;
+}
+
+static inline u64 alloc_lru_idx(struct bch_alloc_v4 a)
+{
+	return bucket_state(a) == BUCKET_cached ? a.io_time[READ] : 0;
+}
+
+static inline u64 alloc_freespace_genbits(struct bch_alloc_v4 a)
+{
+	return ((u64) alloc_gc_gen(a) >> 4) << 56;
+}
+
+static inline struct bpos alloc_freespace_pos(struct bpos pos, struct bch_alloc_v4 a)
+{
+	pos.offset |= alloc_freespace_genbits(a);
+	return pos;
+}
+
 struct bkey_i_alloc_v4 *
 bch2_trans_start_alloc_update(struct btree_trans *, struct btree_iter *, struct bpos);
 
@@ -33,18 +78,21 @@ void bch2_alloc_to_text(struct printbuf *, struct bch_fs *, struct bkey_s_c);
 #define bch2_bkey_ops_alloc (struct bkey_ops) {		\
 	.key_invalid	= bch2_alloc_v1_invalid,	\
 	.val_to_text	= bch2_alloc_to_text,		\
+	.trans_trigger	= bch2_trans_mark_alloc,	\
 	.atomic_trigger	= bch2_mark_alloc,		\
 }
 
 #define bch2_bkey_ops_alloc_v2 (struct bkey_ops) {	\
 	.key_invalid	= bch2_alloc_v2_invalid,	\
 	.val_to_text	= bch2_alloc_to_text,		\
+	.trans_trigger	= bch2_trans_mark_alloc,	\
 	.atomic_trigger	= bch2_mark_alloc,		\
 }
 
 #define bch2_bkey_ops_alloc_v3 (struct bkey_ops) {	\
 	.key_invalid	= bch2_alloc_v3_invalid,	\
 	.val_to_text	= bch2_alloc_to_text,		\
+	.trans_trigger	= bch2_trans_mark_alloc,	\
 	.atomic_trigger	= bch2_mark_alloc,		\
 }
 
@@ -52,6 +100,7 @@ void bch2_alloc_to_text(struct printbuf *, struct bch_fs *, struct bkey_s_c);
 	.key_invalid	= bch2_alloc_v4_invalid,	\
 	.val_to_text	= bch2_alloc_to_text,		\
 	.swab		= bch2_alloc_v4_swab,		\
+	.trans_trigger	= bch2_trans_mark_alloc,	\
 	.atomic_trigger	= bch2_mark_alloc,		\
 }
 
@@ -64,6 +113,10 @@ static inline bool bkey_is_alloc(const struct bkey *k)
 
 int bch2_alloc_read(struct bch_fs *, bool, bool);
 
+int bch2_trans_mark_alloc(struct btree_trans *, struct bkey_s_c,
+			  struct bkey_i *, unsigned);
+int bch2_fs_freespace_init(struct bch_fs *);
+
 static inline void bch2_wake_allocator(struct bch_dev *ca)
 {
 	struct task_struct *p;