From 54fe05c8243a99e16af2bff75ec157b7204e9010 Mon Sep 17 00:00:00 2001 From: Kent Overstreet Date: Fri, 25 Oct 2019 18:54:58 -0400 Subject: bcachefs: Fix an error path race On IO error, bch2_writepages_io_done() will set the page state to indicate nothing's already reserved (since the write didn't happen, we don't know what's already reserved). This can race with the buffered IO path, in between getting a disk reservation and calling bch2_set_page_dirty(). Signed-off-by: Kent Overstreet --- fs/bcachefs/fs-io.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/fs/bcachefs/fs-io.c b/fs/bcachefs/fs-io.c index fea469a4f0b8..6098ed7d8f96 100644 --- a/fs/bcachefs/fs-io.c +++ b/fs/bcachefs/fs-io.c @@ -483,7 +483,12 @@ static void bch2_set_page_dirty(struct bch_fs *c, unsigned sectors = sectors_to_reserve(&s->s[i], res->disk.nr_replicas); - BUG_ON(sectors > res->disk.sectors); + /* + * This can happen if we race with the error path in + * bch2_writepage_io_done(): + */ + sectors = min_t(unsigned, sectors, res->disk.sectors); + s->s[i].replicas_reserved += sectors; res->disk.sectors -= sectors; -- cgit v1.2.3