From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 8476E3C1D7C for ; Wed, 19 Aug 2026 03:57:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787111835; cv=none; b=lpfah19mKPgTPAoQsVbrnUZNGcR04sV5hGH6OEY0Mri5NNl8fsh8Fd0qaK6bHrlgV/alIhKKHXoPKA9BwaVb1CnkQS6FJ8qqLyrB/wIZIhTlw50VsWJMrnF0HaXHVKOKdC1uDnEX/z4H6MlVRyCultCDYYFgizq0uX8ysIMOklk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787111835; c=relaxed/simple; bh=8n3JGqAzdWnD+JcHe/Plj4+/NhJMX2GVz7nELn5VfOU=; h=Message-ID:Date:MIME-Version:Cc:Subject:To:References:From: In-Reply-To:Content-Type; b=jjmhYZXtyvjhw+NJ5ggGw8fYeKuicePbuRrheS73076ZPw1O/4hglDi5wqv4rfGvQFqw0kK+arxkFwLg94+7SjwUW6c7zTsDBJkv+QFVuCNvObJvYKMICQ7NpxrJ9U4mQM6S+IH4opDtNaSvrC66qINwT6R2mCzCAWA+dywm7kY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=C/aDx5cX; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="C/aDx5cX" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 34CB81F000E9; Wed, 19 Aug 2026 03:57:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1787111834; bh=XnES9awESo/xusek8tO1Ts1cKIH860HVRhXuI7ZnJoY=; h=Date:Cc:Subject:To:References:From:In-Reply-To; b=C/aDx5cXDNxDkLxdhXBYBSxhW0ut8sMSbOLffqBSB0XAh+7t7HoubcN4jaxQ1w1Hr CVDxTg2y5cN48zYle3nxhLowZ0nhIPWRPerVg9d4N9XCSFSD4mRlSwU3wT59spUkgq TG2l7qcDlSitqmY+aV/6h4rrhF82R2KWJVNU107utnsc+TfrJmH1LWCBdWBBQS6oc8 yijnEMwRLXoTD0Q3a9Z12Efe7d+QQsz5NophlZqJwqSm3oRj4R92IBm3ZOv4Ksc5TW 34T2teF+o1s/uZxmv/Tls9zS1rqojkwUVsLPSICCevL8pHKaQ5PXGNkKEEfl0O99pA p+LDeXEPDNBJg== Message-ID: <0e1162de-1ad4-4c24-a5c9-cd05c5b08cc0@kernel.org> Date: Wed, 19 Aug 2026 11:57:11 +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: accurately adjust free_sections during free_segment_range To: Daeho Jeong , linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, kernel-team@android.com References: <20260818171412.3201082-1-daeho43@gmail.com> Content-Language: en-US From: Chao Yu In-Reply-To: <20260818171412.3201082-1-daeho43@gmail.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 8/19/26 01:14, Daeho Jeong wrote: > From: Daeho Jeong > > In free_segment_range(), MAIN_SECS(sbi) is temporarily reduced by `secs` > while valid blocks in the truncated range are evacuated by GC. > > However, if any sections within the truncated range were already free, > failing to deduct them from FREE_I(sbi)->free_sections leads to an > over-estimation of available space in the reduced main area, causing > inconsistent free section accounting. Can you please show me an example for above case? I didn't get it. BTW, it needs to rebase this patch on dev-test branch. Thanks, > > Fix this by calculating the number of already-free sections in the > truncated range under segmap_lock, deducting them from free_sections upon > entering free_segment_range(), and restoring them under segmap_lock on exit. > > Signed-off-by: Daeho Jeong > Signed-off-by: Sunmin Jeong > --- > fs/f2fs/gc.c | 15 ++++++++++++++- > 1 file changed, 14 insertions(+), 1 deletion(-) > > diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c > index 787133ee2eb2..f3a6fc6d08ae 100644 > --- a/fs/f2fs/gc.c > +++ b/fs/f2fs/gc.c > @@ -2200,8 +2200,9 @@ int f2fs_gc_range(struct f2fs_sb_info *sbi, > static int free_segment_range(struct f2fs_sb_info *sbi, > unsigned int secs, bool dry_run) > { > - unsigned int next_inuse, start, end; > + unsigned int secno, next_inuse, start, end, end_secno; > struct cp_control cpc = { CP_RESIZE, 0, 0, 0 }; > + unsigned int freed_secs = 0; > int gc_mode, gc_type; > int err = 0; > int type; > @@ -2210,6 +2211,7 @@ static int free_segment_range(struct f2fs_sb_info *sbi, > MAIN_SECS(sbi) -= secs; > start = MAIN_SECS(sbi) * SEGS_PER_SEC(sbi); > end = MAIN_SEGS(sbi) - 1; > + end_secno = GET_SEC_FROM_SEG(sbi, end); > > mutex_lock(&DIRTY_I(sbi)->seglist_lock); > for (gc_mode = 0; gc_mode < MAX_GC_POLICY; gc_mode++) > @@ -2221,6 +2223,14 @@ static int free_segment_range(struct f2fs_sb_info *sbi, > sbi->next_victim_seg[gc_type] = NULL_SEGNO; > mutex_unlock(&DIRTY_I(sbi)->seglist_lock); > > + spin_lock(&FREE_I(sbi)->segmap_lock); > + for (secno = MAIN_SECS(sbi); secno <= end_secno; secno++) { > + if (!test_bit(secno, FREE_I(sbi)->free_secmap)) > + freed_secs++; > + } > + FREE_I(sbi)->free_sections -= freed_secs; > + spin_unlock(&FREE_I(sbi)->segmap_lock); > + > /* Move out cursegs from the target range */ > for (type = CURSEG_HOT_DATA; type < NR_CURSEG_TYPE; type++) { > err = f2fs_allocate_segment_for_resize(sbi, type, start, end); > @@ -2245,6 +2255,9 @@ static int free_segment_range(struct f2fs_sb_info *sbi, > f2fs_bug_on(sbi, 1); > } > out: > + spin_lock(&FREE_I(sbi)->segmap_lock); > + FREE_I(sbi)->free_sections += freed_secs; > + spin_unlock(&FREE_I(sbi)->segmap_lock); > MAIN_SECS(sbi) += secs; > return err; > }