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 5902E185611 for ; Tue, 9 Jul 2024 21:37:53 +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=1720561073; cv=none; b=km3glISLcBnWC8hEuWw6korna24Kl9RzBDEzFGTYDgs96CACovKd4tS96Z/yTIdQ0r3zAQjR9/ggqzbgrj15O/AkIlGTLVnOjqnyjfS886zutpUHha8ew8VSTJRQGBfJepTEqUelrN4/e5j3pn35BwHdnrV8c8aBMOBZcyQsQ/M= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720561073; c=relaxed/simple; bh=gsLdDddWkHg5lq2YwUFU5nuknJozwpUymGvYM9nQiIg=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=b2vV5fVbibA0VoGFOoTWIf+Czm9eg+8CyqAvmZNHNAE9jM6153uBgRxQ4Pnr5qz2nhMdEIy5MOFwFY+KXjwoXhjtvBCb/14+rwGvrCakwjrk+u4xtoAest8dhiPq/At9agtaH9+RvlV0T3iiJ5ysuASm3m89Xlms0TPb3FaRUs0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=u2sQbdUL; 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="u2sQbdUL" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CC2F0C32786; Tue, 9 Jul 2024 21:37:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1720561073; bh=gsLdDddWkHg5lq2YwUFU5nuknJozwpUymGvYM9nQiIg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=u2sQbdUL2DveWVPjld3UkF5xK9RsJt0/zgw/DBnaUDWI5oRY+neLWb02TwwXgQ8f8 PQWbp1O8UTT4yC4s6Va2/skbZyiLALG6N2YfsYkJpuSACpqHCSR7V0egmQX3FN21Yo 41W7jGc0Juiwu0IeT9J6YYL3CH0PcrXlr8XEitaFSFXKjiMmuagYlljioeJr4Y2lvC JSwIjbhTJcyDSDl1rrex62LjiFPG6SlsANrQrK7tVN+5CAbQyiC9+66k1lsBdAX4XQ VI9g76/9wdEsVfGbHNr50mKUoasEGmpI6DHWQm+aqQeyvT+Cm1lH19k1zDsgAWERU/ s8dxAIzFp+QVg== Date: Tue, 9 Jul 2024 21:37:51 +0000 From: Jaegeuk Kim To: Sheng Yong Cc: chao@kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org, daehojeong@google.com Subject: Re: [PATCH v2] f2fs: only fragment segment in the same section Message-ID: References: <20240625075839.3750112-1-shengyong@oppo.com> <20240625121512.3877754-1-shengyong@oppo.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240625121512.3877754-1-shengyong@oppo.com> On 06/25, Sheng Yong wrote: > When new_curseg() is allocating a new segment, if mode=fragment:xxx is > switched on in large section scenario, __get_next_segno() will select > the next segno randomly in the range of [0, maxsegno] in order to > fragment segments. > > If the candidate segno is free, get_new_segment() will use it directly > as the new segment. > > However, if the section of the candidate is not empty, and some other > segments have already been used, and have a different type (e.g NODE) > with the candidate (e.g DATA), GC will complain inconsistent segment > type later. > > This could be reproduced by the following steps: > > dd if=/dev/zero of=test.img bs=1M count=10240 > mkfs.f2fs -s 128 test.img > mount -t f2fs test.img /mnt -o mode=fragment:block > echo 1 > /sys/fs/f2fs/loop0/max_fragment_chunk > echo 512 > /sys/fs/f2fs/loop0/max_fragment_hole > dd if=/dev/zero of=/mnt/testfile bs=4K count=100 > umount /mnt > > F2FS-fs (loop0): Inconsistent segment (4377) type [0, 1] in SSA and SIT > > In order to allow simulating segment fragmentation in large section > scenario, this patch reduces the candidate range: > * if curseg is the last segment in the section, return curseg->segno > to make get_new_segment() itself find the next free segment. > * if curseg is in the middle of the secion, select candicate randomly in > the range of [curseg + 1, last_seg_in_the_same_section] to keep type > consistent. > > Signed-off-by: Sheng Yong > --- > v2: update commit msg > --- > fs/f2fs/segment.c | 15 +++++++++++++-- > 1 file changed, 13 insertions(+), 2 deletions(-) > > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c > index a0ce3d080f80a..55d474f5c2103 100644 > --- a/fs/f2fs/segment.c > +++ b/fs/f2fs/segment.c > @@ -2782,10 +2782,21 @@ static unsigned int __get_next_segno(struct f2fs_sb_info *sbi, int type) > { > struct curseg_info *curseg = CURSEG_I(sbi, type); > unsigned short seg_type = curseg->seg_type; > + unsigned int hint; > > sanity_check_seg_type(sbi, seg_type); > - if (f2fs_need_rand_seg(sbi)) > - return get_random_u32_below(MAIN_SECS(sbi) * SEGS_PER_SEC(sbi)); > + if (f2fs_need_rand_seg(sbi)) { > + if (__is_large_section(sbi)) { > + hint = GET_SEC_FROM_SEG(sbi, curseg->segno); > + if (GET_SEC_FROM_SEG(sbi, curseg->segno + 1) != hint) > + return curseg->segno; > + return get_random_u32_inclusive(curseg->segno + 1, > + GET_SEG_FROM_SEC(sbi, hint + 1) - 1); > + } else { > + return get_random_u32_below(MAIN_SECS(sbi) * > + SEGS_PER_SEC(sbi)); > + } > + } > > if (__is_large_section(sbi)) > return curseg->segno; if (__is_large_section(sbi)) { if (f2fs_need_rand_seg(sbi)) { unsigned int hint = GET_SEC_FROM_SEG(sbi, curseg->segno); if (GET_SEC_FROM_SEG(sbi, curseg->segno + 1) != hint) return curseg->segno; return get_random_u32_inclusive(curseg->segno + 1, GET_SEG_FROM_SEC(sbi, hint + 1) - 1); } return curseg->segno; } else if (f2fs_need_rand_seg(sbi)) { return get_random_u32_below(MAIN_SECS(sbi) * SEGS_PER_SEC(sbi)); } > -- > 2.40.1