Commit 3e72acb7 authored by Kent Overstreet's avatar Kent Overstreet
Browse files

bcachefs: Ensure btree node scan runs before checking for scanned nodes 



Previously, calling bch2_btree_has_scanned_nodes() when btree node
scan hadn't actually run would erroniously return false - causing us to
think a btree was entirely gone.

This fixes a 6.16 regression from moving the scheduling of btree node
scan out of bch2_btree_lost_data() (fixing the bug where we'd schedule
it persistently in the superblock) and only scheduling it when
check_toploogy() is asking for scanned btree nodes.

Signed-off-by: default avatarKent Overstreet <kent.overstreet@linux.dev>
parent 1dcea078

fs/bcachefs/btree_gc.c

+18 −11
Original line number Diff line number Diff line
@@ -534,32 +534,39 @@ static int bch2_btree_repair_topology_recurse(struct btree_trans *trans, struct 
	return ret;

}



static int bch2_check_root(struct btree_trans *trans, enum btree_id i,

static int bch2_check_root(struct btree_trans *trans, enum btree_id btree,

			   bool *reconstructed_root)

{

	struct bch_fs *c = trans->c;

	struct btree_root *r = bch2_btree_id_root(c, i);

	struct btree_root *r = bch2_btree_id_root(c, btree);

	struct printbuf buf = PRINTBUF;

	int ret = 0;



	bch2_btree_id_to_text(&buf, i);

	bch2_btree_id_to_text(&buf, btree);



	if (r->error) {

		bch_info(c, "btree root %s unreadable, must recover from scan", buf.buf);



		r->alive = false;

		r->error = 0;

		ret = bch2_btree_has_scanned_nodes(c, btree);

		if (ret < 0)

			goto err;



		if (!bch2_btree_has_scanned_nodes(c, i)) {

		if (!ret) {

			__fsck_err(trans,

				   FSCK_CAN_FIX|(!btree_id_important(i) ? FSCK_AUTOFIX : 0),

				   FSCK_CAN_FIX|(!btree_id_important(btree) ? FSCK_AUTOFIX : 0),

				   btree_root_unreadable_and_scan_found_nothing,

				   "no nodes found for btree %s, continue?", buf.buf);

			bch2_btree_root_alloc_fake_trans(trans, i, 0);



			r->alive = false;

			r->error = 0;

			bch2_btree_root_alloc_fake_trans(trans, btree, 0);

		} else {

			bch2_btree_root_alloc_fake_trans(trans, i, 1);

			bch2_shoot_down_journal_keys(c, i, 1, BTREE_MAX_DEPTH, POS_MIN, SPOS_MAX);

			ret = bch2_get_scanned_nodes(c, i, 0, POS_MIN, SPOS_MAX);

			r->alive = false;

			r->error = 0;

			bch2_btree_root_alloc_fake_trans(trans, btree, 1);



			bch2_shoot_down_journal_keys(c, btree, 1, BTREE_MAX_DEPTH, POS_MIN, SPOS_MAX);

			ret = bch2_get_scanned_nodes(c, btree, 0, POS_MIN, SPOS_MAX);

			if (ret)

				goto err;

		}

fs/bcachefs/btree_node_scan.c

+5 −1
Original line number Diff line number Diff line
@@ -521,8 +521,12 @@ bool bch2_btree_node_is_stale(struct bch_fs *c, struct btree *b) 
	return false;

}



bool bch2_btree_has_scanned_nodes(struct bch_fs *c, enum btree_id btree)

int bch2_btree_has_scanned_nodes(struct bch_fs *c, enum btree_id btree)

{

	int ret = bch2_run_print_explicit_recovery_pass(c, BCH_RECOVERY_PASS_scan_for_btree_nodes);

	if (ret)

		return ret;



	struct found_btree_node search = {

		.btree_id	= btree,

		.level		= 0,

fs/bcachefs/btree_node_scan.h

+1 −1
Original line number Diff line number Diff line
@@ -4,7 +4,7 @@ 


int bch2_scan_for_btree_nodes(struct bch_fs *);

bool bch2_btree_node_is_stale(struct bch_fs *, struct btree *);

bool bch2_btree_has_scanned_nodes(struct bch_fs *, enum btree_id);

int bch2_btree_has_scanned_nodes(struct bch_fs *, enum btree_id);

int bch2_get_scanned_nodes(struct bch_fs *, enum btree_id, unsigned, struct bpos, struct bpos);

void bch2_find_btree_nodes_exit(struct find_btree_nodes *);