The smp_rmb() guarantees that reads from reservations.counter occur before accessing cur_entry_u64s. It's paired with the atomic64_try_cmpxchg in journal_entry_open.
Signed-off-by: Alan Huang <[email protected]> --- fs/bcachefs/journal.h | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/fs/bcachefs/journal.h b/fs/bcachefs/journal.h index ab68c5c4d8d8..47828771f9c2 100644 --- a/fs/bcachefs/journal.h +++ b/fs/bcachefs/journal.h @@ -350,8 +350,10 @@ static inline int journal_res_get_fast(struct journal *j, /* * Check if there is still room in the current journal - * entry: + * entry, smp_rmb() guarantees that reads from reservations.counter + * occur before accessing cur_entry_u64s: */ + smp_rmb(); if (new.cur_entry_offset + res->u64s > j->cur_entry_u64s) return 0; -- 2.48.1
