Commit c502b5b8 authored by Kent Overstreet's avatar Kent Overstreet
Browse files

bcachefs; Fix deadlock in bch2_btree_update_start() 



BCH_TRANS_COMMIT_journal_reclaim with watermark != BCH_WATERMARK_reclaim
means nonblocking, and we need the journal_res_get() in
btree_update_start() to respect that.

In a future refactoring we'll be deleting
BCH_TRANS_COMMIT_journal_reclaim and replacing it with an explicit
BCH_TRANS_COMMIT_nonblocking.

Signed-off-by: default avatarKent Overstreet <kent.overstreet@linux.dev>
parent b38114dd

fs/bcachefs/btree_update_interior.c

+9 −4
Original line number Diff line number Diff line
@@ -1067,13 +1067,18 @@ bch2_btree_update_start(struct btree_trans *trans, struct btree_path *path, 
	flags &= ~BCH_WATERMARK_MASK;

	flags |= watermark;



	if (!(flags & BCH_TRANS_COMMIT_journal_reclaim) &&

	    watermark < c->journal.watermark) {

	if (watermark < c->journal.watermark) {

		struct journal_res res = { 0 };

		unsigned journal_flags = watermark|JOURNAL_RES_GET_CHECK;



		if ((flags & BCH_TRANS_COMMIT_journal_reclaim) &&

		    watermark != BCH_WATERMARK_reclaim)

			journal_flags |= JOURNAL_RES_GET_NONBLOCK;



		ret = drop_locks_do(trans,

			bch2_journal_res_get(&c->journal, &res, 1,

					     watermark|JOURNAL_RES_GET_CHECK));

			bch2_journal_res_get(&c->journal, &res, 1, journal_flags));

		if (bch2_err_matches(ret, BCH_ERR_operation_blocked))

			ret = -BCH_ERR_journal_reclaim_would_deadlock;

		if (ret)

			return ERR_PTR(ret);

	}