From 256b74d0b034ff61709fca64d58f81746186eaef Mon Sep 17 00:00:00 2001 From: Richard Yao Date: Thu, 3 Nov 2022 12:58:14 -0400 Subject: [PATCH] Address warnings about possible division by zero from clangsa * The complaint in ztest_replay_write() is only possible if something went horribly wrong. An assertion will silence this and if it goes off, we will know that something is wrong. * The complaint in spa_estimate_metaslabs_to_flush() is not impossible, but seems very unlikely. We resolve this by passing the value from the `MIN()` that does not go to infinity when the variable is zero. There was a third report from Clang's scan-build, but that was a definite false positive and disappeared when checked again through Clang's static analyzer with Z3 refution via CodeChecker. Reviewed-by: Brian Behlendorf Signed-off-by: Richard Yao Closes #14124 --- cmd/ztest/ztest.c | 1 + module/zfs/spa_log_spacemap.c | 3 ++- 2 files changed, 3 insertions(+), 1 deletion(-) diff --git a/cmd/ztest/ztest.c b/cmd/ztest/ztest.c index a580396ebd..fb4297478c 100644 --- a/cmd/ztest/ztest.c +++ b/cmd/ztest/ztest.c @@ -2193,6 +2193,7 @@ ztest_replay_write(void *arg1, void *arg2, boolean_t byteswap) * but not always, because we also want to verify correct * behavior when the data was not recently read into cache. */ + ASSERT(doi.doi_data_block_size); ASSERT0(offset % doi.doi_data_block_size); if (ztest_random(4) != 0) { int prefetch = ztest_random(2) ? diff --git a/module/zfs/spa_log_spacemap.c b/module/zfs/spa_log_spacemap.c index 0dfe5b8395..6a27f57595 100644 --- a/module/zfs/spa_log_spacemap.c +++ b/module/zfs/spa_log_spacemap.c @@ -690,7 +690,8 @@ spa_estimate_metaslabs_to_flush(spa_t *spa) * based on the incoming rate until we exceed it. */ if (available_blocks >= 0 && available_txgs >= 0) { - uint64_t skip_txgs = MIN(available_txgs + 1, + uint64_t skip_txgs = (incoming == 0) ? + available_txgs + 1 : MIN(available_txgs + 1, (available_blocks / incoming) + 1); available_blocks -= (skip_txgs * incoming); available_txgs -= skip_txgs;