From b02113e2c46ed16855bf9dc767d333a2b54e4416 Mon Sep 17 00:00:00 2001 From: Kent Overstreet Date: Fri, 4 Mar 2022 19:16:04 -0500 Subject: bcachefs: Fix usage of six lock's percpu mode Six locks have a percpu mode, which we use for interior btree nodes, as well as btree key cache keys for the subvolumes btree. We've been switching locks back and forth between percpu and non percpu mode as needed, but it turns out this is racy - when we're reusing an existing node, other threads could be attempting to lock it while we're switching it between modes. This patch fixes this by never switching 'struct btree' between the two modes, and instead segragating them between two different freed lists. Signed-off-by: Kent Overstreet --- fs/bcachefs/debug.c | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'fs/bcachefs/debug.c') diff --git a/fs/bcachefs/debug.c b/fs/bcachefs/debug.c index 1fff03d301a9..457fcee7d8e1 100644 --- a/fs/bcachefs/debug.c +++ b/fs/bcachefs/debug.c @@ -443,6 +443,11 @@ static void bch2_cached_btree_node_to_text(struct printbuf *out, struct bch_fs * bch2_flags_to_text(out, bch2_btree_node_flags, b->flags); pr_newline(out); + pr_buf(out, "pcpu read locks: "); + pr_tab(out); + pr_buf(out, "%u", b->c.lock.readers != NULL); + pr_newline(out); + pr_buf(out, "written:"); pr_tab(out); pr_buf(out, "%u", b->written); -- cgit v1.2.3