bcachefs: Initial commit

Initially forked from drivers/md/bcache, bcachefs is a new copy-on-write
filesystem with every feature you could possibly want.

Website: https://bcachefs.org

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

1 files changed, 374 insertions, 0 deletions

diff --git a/fs/bcachefs/btree_update_interior.h b/fs/bcachefs/btree_update_interior.h
new file mode 100644
index 000000000000..7a19a52bbcff
--- /dev/null
+++ b/fs/bcachefs/btree_update_interior.h
@@ -0,0 +1,374 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _BCACHEFS_BTREE_UPDATE_INTERIOR_H
+#define _BCACHEFS_BTREE_UPDATE_INTERIOR_H
+
+#include "btree_cache.h"
+#include "btree_locking.h"
+#include "btree_update.h"
+
+struct btree_reserve {
+	struct disk_reservation	disk_res;
+	unsigned		nr;
+	struct btree		*b[BTREE_RESERVE_MAX];
+};
+
+void __bch2_btree_calc_format(struct bkey_format_state *, struct btree *);
+bool bch2_btree_node_format_fits(struct bch_fs *c, struct btree *,
+				struct bkey_format *);
+
+/* Btree node freeing/allocation: */
+
+/*
+ * Tracks a btree node that has been (or is about to be) freed in memory, but
+ * has _not_ yet been freed on disk (because the write that makes the new
+ * node(s) visible and frees the old hasn't completed yet)
+ */
+struct pending_btree_node_free {
+	bool			index_update_done;
+
+	__le64			seq;
+	enum btree_id		btree_id;
+	unsigned		level;
+	__BKEY_PADDED(key, BKEY_BTREE_PTR_VAL_U64s_MAX);
+};
+
+/*
+ * Tracks an in progress split/rewrite of a btree node and the update to the
+ * parent node:
+ *
+ * When we split/rewrite a node, we do all the updates in memory without
+ * waiting for any writes to complete - we allocate the new node(s) and update
+ * the parent node, possibly recursively up to the root.
+ *
+ * The end result is that we have one or more new nodes being written -
+ * possibly several, if there were multiple splits - and then a write (updating
+ * an interior node) which will make all these new nodes visible.
+ *
+ * Additionally, as we split/rewrite nodes we free the old nodes - but the old
+ * nodes can't be freed (their space on disk can't be reclaimed) until the
+ * update to the interior node that makes the new node visible completes -
+ * until then, the old nodes are still reachable on disk.
+ *
+ */
+struct btree_update {
+	struct closure			cl;
+	struct bch_fs			*c;
+
+	struct list_head		list;
+
+	/* What kind of update are we doing? */
+	enum {
+		BTREE_INTERIOR_NO_UPDATE,
+		BTREE_INTERIOR_UPDATING_NODE,
+		BTREE_INTERIOR_UPDATING_ROOT,
+		BTREE_INTERIOR_UPDATING_AS,
+	} mode;
+
+	unsigned			must_rewrite:1;
+	unsigned			nodes_written:1;
+
+	enum btree_id			btree_id;
+
+	struct btree_reserve		*reserve;
+
+	/*
+	 * BTREE_INTERIOR_UPDATING_NODE:
+	 * The update that made the new nodes visible was a regular update to an
+	 * existing interior node - @b. We can't write out the update to @b
+	 * until the new nodes we created are finished writing, so we block @b
+	 * from writing by putting this btree_interior update on the
+	 * @b->write_blocked list with @write_blocked_list:
+	 */
+	struct btree			*b;
+	struct list_head		write_blocked_list;
+
+	/*
+	 * BTREE_INTERIOR_UPDATING_AS: btree node we updated was freed, so now
+	 * we're now blocking another btree_update
+	 * @parent_as - btree_update that's waiting on our nodes to finish
+	 * writing, before it can make new nodes visible on disk
+	 * @wait - list of child btree_updates that are waiting on this
+	 * btree_update to make all the new nodes visible before they can free
+	 * their old btree nodes
+	 */
+	struct btree_update		*parent_as;
+	struct closure_waitlist		wait;
+
+	/*
+	 * We may be freeing nodes that were dirty, and thus had journal entries
+	 * pinned: we need to transfer the oldest of those pins to the
+	 * btree_update operation, and release it when the new node(s)
+	 * are all persistent and reachable:
+	 */
+	struct journal_entry_pin	journal;
+
+	u64				journal_seq;
+
+	/*
+	 * Nodes being freed:
+	 * Protected by c->btree_node_pending_free_lock
+	 */
+	struct pending_btree_node_free	pending[BTREE_MAX_DEPTH + GC_MERGE_NODES];
+	unsigned			nr_pending;
+
+	/* New nodes, that will be made reachable by this update: */
+	struct btree			*new_nodes[BTREE_MAX_DEPTH * 2 + GC_MERGE_NODES];
+	unsigned			nr_new_nodes;
+
+	/* Only here to reduce stack usage on recursive splits: */
+	struct keylist			parent_keys;
+	/*
+	 * Enough room for btree_split's keys without realloc - btree node
+	 * pointers never have crc/compression info, so we only need to acount
+	 * for the pointers for three keys
+	 */
+	u64				inline_keys[BKEY_BTREE_PTR_U64s_MAX * 3];
+};
+
+#define for_each_pending_btree_node_free(c, as, p)			\
+	list_for_each_entry(as, &c->btree_interior_update_list, list)	\
+		for (p = as->pending; p < as->pending + as->nr_pending; p++)
+
+void bch2_btree_node_free_inmem(struct bch_fs *, struct btree *,
+				struct btree_iter *);
+void bch2_btree_node_free_never_inserted(struct bch_fs *, struct btree *);
+void bch2_btree_open_bucket_put(struct bch_fs *, struct btree *);
+
+struct btree *__bch2_btree_node_alloc_replacement(struct btree_update *,
+						  struct btree *,
+						  struct bkey_format);
+
+void bch2_btree_update_done(struct btree_update *);
+struct btree_update *
+bch2_btree_update_start(struct bch_fs *, enum btree_id, unsigned,
+			unsigned, struct closure *);
+
+void bch2_btree_interior_update_will_free_node(struct btree_update *,
+					       struct btree *);
+
+void bch2_btree_insert_node(struct btree_update *, struct btree *,
+			    struct btree_iter *, struct keylist *,
+			    unsigned);
+int bch2_btree_split_leaf(struct bch_fs *, struct btree_iter *, unsigned);
+
+void __bch2_foreground_maybe_merge(struct bch_fs *, struct btree_iter *,
+				   unsigned, unsigned, enum btree_node_sibling);
+
+static inline void bch2_foreground_maybe_merge_sibling(struct bch_fs *c,
+					struct btree_iter *iter,
+					unsigned level, unsigned flags,
+					enum btree_node_sibling sib)
+{
+	struct btree *b;
+
+	/*
+	 * iterators are inconsistent when they hit end of leaf, until
+	 * traversed again
+	 *
+	 * XXX inconsistent how?
+	 */
+	if (iter->flags & BTREE_ITER_AT_END_OF_LEAF)
+		return;
+
+	if (iter->uptodate >= BTREE_ITER_NEED_TRAVERSE)
+		return;
+
+	if (!bch2_btree_node_relock(iter, level))
+		return;
+
+	b = iter->l[level].b;
+	if (b->sib_u64s[sib] > c->btree_foreground_merge_threshold)
+		return;
+
+	__bch2_foreground_maybe_merge(c, iter, level, flags, sib);
+}
+
+static inline void bch2_foreground_maybe_merge(struct bch_fs *c,
+					       struct btree_iter *iter,
+					       unsigned level,
+					       unsigned flags)
+{
+	bch2_foreground_maybe_merge_sibling(c, iter, level, flags,
+					    btree_prev_sib);
+	bch2_foreground_maybe_merge_sibling(c, iter, level, flags,
+					    btree_next_sib);
+}
+
+void bch2_btree_set_root_for_read(struct bch_fs *, struct btree *);
+void bch2_btree_root_alloc(struct bch_fs *, enum btree_id);
+
+static inline unsigned btree_update_reserve_required(struct bch_fs *c,
+						     struct btree *b)
+{
+	unsigned depth = btree_node_root(c, b)->level + 1;
+
+	/*
+	 * Number of nodes we might have to allocate in a worst case btree
+	 * split operation - we split all the way up to the root, then allocate
+	 * a new root, unless we're already at max depth:
+	 */
+	if (depth < BTREE_MAX_DEPTH)
+		return (depth - b->level) * 2 + 1;
+	else
+		return (depth - b->level) * 2 - 1;
+}
+
+static inline void btree_node_reset_sib_u64s(struct btree *b)
+{
+	b->sib_u64s[0] = b->nr.live_u64s;
+	b->sib_u64s[1] = b->nr.live_u64s;
+}
+
+static inline void *btree_data_end(struct bch_fs *c, struct btree *b)
+{
+	return (void *) b->data + btree_bytes(c);
+}
+
+static inline struct bkey_packed *unwritten_whiteouts_start(struct bch_fs *c,
+							    struct btree *b)
+{
+	return (void *) ((u64 *) btree_data_end(c, b) - b->whiteout_u64s);
+}
+
+static inline struct bkey_packed *unwritten_whiteouts_end(struct bch_fs *c,
+							  struct btree *b)
+{
+	return btree_data_end(c, b);
+}
+
+static inline void *write_block(struct btree *b)
+{
+	return (void *) b->data + (b->written << 9);
+}
+
+static inline bool bset_written(struct btree *b, struct bset *i)
+{
+	return (void *) i < write_block(b);
+}
+
+static inline bool bset_unwritten(struct btree *b, struct bset *i)
+{
+	return (void *) i > write_block(b);
+}
+
+static inline ssize_t __bch_btree_u64s_remaining(struct bch_fs *c,
+						 struct btree *b,
+						 void *end)
+{
+	ssize_t used = bset_byte_offset(b, end) / sizeof(u64) +
+		b->whiteout_u64s +
+		b->uncompacted_whiteout_u64s;
+	ssize_t total = c->opts.btree_node_size << 6;
+
+	return total - used;
+}
+
+static inline size_t bch_btree_keys_u64s_remaining(struct bch_fs *c,
+						   struct btree *b)
+{
+	ssize_t remaining = __bch_btree_u64s_remaining(c, b,
+				btree_bkey_last(b, bset_tree_last(b)));
+
+	BUG_ON(remaining < 0);
+
+	if (bset_written(b, btree_bset_last(b)))
+		return 0;
+
+	return remaining;
+}
+
+static inline unsigned btree_write_set_buffer(struct btree *b)
+{
+	/*
+	 * Could buffer up larger amounts of keys for btrees with larger keys,
+	 * pending benchmarking:
+	 */
+	return 4 << 10;
+}
+
+static inline struct btree_node_entry *want_new_bset(struct bch_fs *c,
+						     struct btree *b)
+{
+	struct bset *i = btree_bset_last(b);
+	struct btree_node_entry *bne = max(write_block(b),
+			(void *) btree_bkey_last(b, bset_tree_last(b)));
+	ssize_t remaining_space =
+		__bch_btree_u64s_remaining(c, b, &bne->keys.start[0]);
+
+	if (unlikely(bset_written(b, i))) {
+		if (remaining_space > (ssize_t) (block_bytes(c) >> 3))
+			return bne;
+	} else {
+		if (unlikely(vstruct_bytes(i) > btree_write_set_buffer(b)) &&
+		    remaining_space > (ssize_t) (btree_write_set_buffer(b) >> 3))
+			return bne;
+	}
+
+	return NULL;
+}
+
+static inline void unreserve_whiteout(struct btree *b, struct bset_tree *t,
+				      struct bkey_packed *k)
+{
+	if (bset_written(b, bset(b, t))) {
+		EBUG_ON(b->uncompacted_whiteout_u64s <
+			bkeyp_key_u64s(&b->format, k));
+		b->uncompacted_whiteout_u64s -=
+			bkeyp_key_u64s(&b->format, k);
+	}
+}
+
+static inline void reserve_whiteout(struct btree *b, struct bset_tree *t,
+				    struct bkey_packed *k)
+{
+	if (bset_written(b, bset(b, t))) {
+		BUG_ON(!k->needs_whiteout);
+		b->uncompacted_whiteout_u64s +=
+			bkeyp_key_u64s(&b->format, k);
+	}
+}
+
+/*
+ * write lock must be held on @b (else the dirty bset that we were going to
+ * insert into could be written out from under us)
+ */
+static inline bool bch2_btree_node_insert_fits(struct bch_fs *c,
+					      struct btree *b, unsigned u64s)
+{
+	if (unlikely(btree_node_fake(b)))
+		return false;
+
+	if (btree_node_is_extents(b)) {
+		/* The insert key might split an existing key
+		 * (bch2_insert_fixup_extent() -> BCH_EXTENT_OVERLAP_MIDDLE case:
+		 */
+		u64s += BKEY_EXTENT_U64s_MAX;
+	}
+
+	return u64s <= bch_btree_keys_u64s_remaining(c, b);
+}
+
+static inline bool journal_res_insert_fits(struct btree_insert *trans,
+					   struct btree_insert_entry *insert)
+{
+	unsigned u64s = 0;
+	struct btree_insert_entry *i;
+
+	/*
+	 * If we didn't get a journal reservation, we're in journal replay and
+	 * we're not journalling updates:
+	 */
+	if (!trans->journal_res.ref)
+		return true;
+
+	for (i = insert; i < trans->entries + trans->nr; i++)
+		u64s += jset_u64s(i->k->k.u64s + i->extra_res);
+
+	return u64s <= trans->journal_res.u64s;
+}
+
+ssize_t bch2_btree_updates_print(struct bch_fs *, char *);
+
+size_t bch2_btree_interior_updates_nr_pending(struct bch_fs *);
+
+#endif /* _BCACHEFS_BTREE_UPDATE_INTERIOR_H */