From a3ea8c8ee6d01aba0d15b4619b8641376fef57e2 Mon Sep 17 00:00:00 2001 From: Rob Norris Date: Mon, 24 Jul 2023 18:02:21 +1000 Subject: [PATCH] dbuf_sync_leaf: check DB_READ in state assertions Block cloning introduced a new state transition from DB_NOFILL to DB_READ. This occurs when a block is cloned and then read on the current txg. In this case, the clone will move the dbuf to DB_NOFILL, and then the read will be issued for the overidden block pointer. If that read is still outstanding when it comes time to write, the dbuf will be in DB_READ, which is not handled by the checks in dbuf_sync_leaf, thus tripping the assertions. This updates those checks to allow DB_READ as a valid state iff the dirty record is for a BRT write and there is a override block pointer. This is a safe situation because the block already exists, so there's nothing that could change from underneath the read. Reviewed-by: Brian Behlendorf Reviewed-by: Kay Pedersen Signed-off-by: Rob Norris Original-patch-by: Kay Pedersen Sponsored-By: OpenDrives Inc. Sponsored-By: Klara Inc. Closes #15050 --- module/zfs/dbuf.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/module/zfs/dbuf.c b/module/zfs/dbuf.c index fbeac866a..b7453578a 100644 --- a/module/zfs/dbuf.c +++ b/module/zfs/dbuf.c @@ -4457,6 +4457,15 @@ dbuf_sync_leaf(dbuf_dirty_record_t *dr, dmu_tx_t *tx) } else if (db->db_state == DB_FILL) { /* This buffer was freed and is now being re-filled */ ASSERT(db->db.db_data != dr->dt.dl.dr_data); + } else if (db->db_state == DB_READ) { + /* + * This buffer has a clone we need to write, and an in-flight + * read on the BP we're about to clone. Its safe to issue the + * write here because the read has already been issued and the + * contents won't change. + */ + ASSERT(dr->dt.dl.dr_brtwrite && + dr->dt.dl.dr_override_state == DR_OVERRIDDEN); } else { ASSERT(db->db_state == DB_CACHED || db->db_state == DB_NOFILL); }