From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 60D1F31E846 for ; Wed, 11 Mar 2026 13:44:09 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773236649; cv=none; b=B8Vt43kk/y0WCtFn29v0gWtC7JhnTA+eB+jMqFq0exceshn22XiyWmBplqu47Dnqu3EpHU1g9vP4ap9I3QGVlwp34om+QS6ZPuHra/Stm0JhUPam0tU2aaEO+RAGnrtm+wnI8GPdVOmsErtXORKUw4qtf7e+slq7sKCNyCIcY2I= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773236649; c=relaxed/simple; bh=OD21PrssA79FIcWIFDQaYFQnABNyQry8BnIpPYlAW5k=; h=Message-ID:Date:MIME-Version:Cc:Subject:To:References:From: In-Reply-To:Content-Type; b=IiJag1v+nrbWIAidZ3DLJSzhS6kM48pyb8liNgENOb9LNazAi3OCmeuCKIVj0iFSQ11ZAHTuzB33tpKc6xuiFwKATsqqi+J8I6/deJjrDcg5cEw8dJ/xXzvKrZYVZtlpD9iiwm/el1pWY0gg+dOSU7e2hddjg+S/xRxcEWRQJVg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=dso26tIm; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="dso26tIm" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 38BEAC4CEF7; Wed, 11 Mar 2026 13:44:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1773236649; bh=OD21PrssA79FIcWIFDQaYFQnABNyQry8BnIpPYlAW5k=; h=Date:Cc:Subject:To:References:From:In-Reply-To:From; b=dso26tImuBnrdem09GdQ3Ix/mRG/Fa9tr1n3i89YtRRhgtw2QyzekfboosrH1WMmB nHeyXHVfzpWi3kVNcjUbvVG6xjQimSB2/bWbuzWz77CcDsJaBZgvMozqjp0s5i21m7 RclE4EwcliBAEqN5f1cAUlMSnGgyFeQYZSJiDKZ7asgUgcVaSWsRkXN9I15QczBxmy ofkAQfvQb8zABOdisx2+GRb1lVEcw1bhSz3M0ckiOyLrLH51o9GwU/Ec2/EGk/aC4h I+6FbLxTW+RuMmqvJ2TU8jq5wiRHs7iVxl/FPdBFVwOtoUbTF+WNsU76p7qc/D3OyG +thI2B3+88KsQ== Message-ID: Date: Wed, 11 Mar 2026 21:44:04 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Cc: chao@kernel.org, Daeho Jeong Subject: Re: [f2fs-dev] [PATCH] f2fs: fix to skip empty sections in f2fs_get_victim To: Daeho Jeong , linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, kernel-team@android.com References: <20260310175428.1156719-1-daeho43@gmail.com> Content-Language: en-US From: Chao Yu In-Reply-To: <20260310175428.1156719-1-daeho43@gmail.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 2026/3/11 01:54, Daeho Jeong wrote: > From: Daeho Jeong > > In age-based victim selection (ATGC, AT_SSR, or GC_CB), f2fs_get_victim > can encounter sections with zero valid blocks. This situation often > arises when checkpoint is disabled or due to race conditions between > SIT updates and dirty list management. > > In such cases, f2fs_get_section_mtime() returns INVALID_MTIME, which > subsequently triggers a fatal f2fs_bug_on(sbi, mtime == INVALID_MTIME) > in add_victim_entry() or get_cb_cost(). > > This patch adds a check in f2fs_get_victim's selection loop to skip > sections with no valid blocks. This prevents unnecessary age > calculations for empty sections and avoids the associated kernel panic. > This change also allows removing redundant checks in add_victim_entry(). > > Signed-off-by: Daeho Jeong > --- > fs/f2fs/gc.c | 9 +++------ > 1 file changed, 3 insertions(+), 6 deletions(-) > > diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c > index 2e0f67946914..981eac629fe9 100644 > --- a/fs/f2fs/gc.c > +++ b/fs/f2fs/gc.c > @@ -521,12 +521,6 @@ static void add_victim_entry(struct f2fs_sb_info *sbi, > struct sit_info *sit_i = SIT_I(sbi); > unsigned long long mtime = 0; > > - if (unlikely(is_sbi_flag_set(sbi, SBI_CP_DISABLED))) { > - if (p->gc_mode == GC_AT && > - get_valid_blocks(sbi, segno, true) == 0) > - return; > - } > - > mtime = f2fs_get_section_mtime(sbi, segno); > f2fs_bug_on(sbi, mtime == INVALID_MTIME); > > @@ -889,6 +883,9 @@ int f2fs_get_victim(struct f2fs_sb_info *sbi, unsigned int *result, > if (sec_usage_check(sbi, secno)) > goto next; > > + if (!get_valid_blocks(sbi, segno, true)) > + goto next; Well, for f2fs_get_victim(, AT_SSR), once there are no dirty segment, if we don't count free segment as candidates, then, we can not find any valid victim? Thanks, > + > /* Don't touch checkpointed data */ > if (unlikely(is_sbi_flag_set(sbi, SBI_CP_DISABLED))) { > if (p.alloc_mode == LFS) {