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 406E0288C0E for ; Fri, 23 Jan 2026 04:07:06 +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=1769141227; cv=none; b=mubGSuflCDv2//cOz0Bno08x+1wBtW2owdSBWtPagclUtrJxfi1qNvxgcCdoLs7DCBuiOYG+3DBxe0RHC1/YnToC65xILFSonqpjU3vl0zL18OTc+M88YGsTynPP1KytfSOxtwW1YP+4UqFGn354UZIlkd2aHJnWiMHibvK3Wtw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769141227; c=relaxed/simple; bh=oPemzsRDwcvtv2dxilZkGkwwsxrceXLp8Vv86KtzWi0=; h=Message-ID:Date:MIME-Version:Cc:Subject:To:References:From: In-Reply-To:Content-Type; b=L4m/oXZ3rz1Sa4CQ7BVgW+czAvcrs15De0yC3Y8ddWWDgdn9AMAjag4/lpgqCatEeh3C86S8owFzp3DuWyR7a1dNUFro1vottxW7WBMqo9jk62cXfs3OGi9nLYkOEabonXW9I6vXGBs7DFfVfro9kTm41/EoFdnKKEmMAMvm+N4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=NFJrBqnk; 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="NFJrBqnk" Received: by smtp.kernel.org (Postfix) with ESMTPSA id F15EFC4CEF1; Fri, 23 Jan 2026 04:07:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1769141226; bh=oPemzsRDwcvtv2dxilZkGkwwsxrceXLp8Vv86KtzWi0=; h=Date:Cc:Subject:To:References:From:In-Reply-To:From; b=NFJrBqnk1pv+aOwszIgLU12EDlgiQZmCMH4K7zUsm3WuhuO2adeKgpT2pXj7K4RR1 CIYdwQWzsBHesr+cp2W5RyAf+qrOXhmXIw8T6lmjmhE2hGM5IaoopXEpTSMWyrhcs+ jIYEwW8FyjxS2/EFVXmB6OFcB852LPuxl+PX6FwM5furxdtyGYk52ufgAU0KYXz9U2 9AJJY2v+E347ZeaTtpak7r9GuQAEKLWD/FEMkG3MKeBi7L6RStLQUBduxI7kYbgT4r 64RPQDdck9VaSutLS6mhCy0MKVgY5hTnnXOVA6dnMhoJtWa1TnVDZ+KfxqtAyx69ie OsWEZsTpPW3Ww== Message-ID: <02ef4102-f143-4939-b3db-71dbaf74b5b7@kernel.org> Date: Fri, 23 Jan 2026 12:07:04 +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, Sungjong Seo , Sunmin Jeong Subject: Re: [PATCH v2] f2fs: optimize f2fs_overwrite_io() for f2fs_iomap_begin To: Yeongjin Gil , jaegeuk@kernel.org, jyh429@gmail.com, linux-f2fs-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org References: <20260122104527.416871-1-youngjin.gil@samsung.com> Content-Language: en-US From: Chao Yu In-Reply-To: <20260122104527.416871-1-youngjin.gil@samsung.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 1/22/2026 6:45 PM, Yeongjin Gil wrote: > When overwriting already allocated blocks, f2fs_iomap_begin() calls > f2fs_overwrite_io() to check block mappings. However, > f2fs_overwrite_io() iterates through all mapped blocks in the range, > which can be inefficient for fragmented files with large I/O requests. > > This patch optimizes f2fs_overwrite_io() by adding a 'check_first' > parameter and introducing __f2fs_overwrite_io() helper. When called from > f2fs_iomap_begin(), we only check the first mapping to determine if the > range is already allocated, which is sufficient for setting > map.m_may_create. > > This optimization significantly reduces the number of f2fs_map_blocks() > calls in f2fs_overwrite_io() when called from f2fs_iomap_begin(), > especially for fragmented files with large I/O requests. > Cc: stable@kernel.org > Fixes: 351bc761338d ("f2fs: optimize f2fs DIO overwrites") > Reviewed-by: Sungjong Seo > Reviewed-by: Sunmin Jeong > Signed-off-by: Yeongjin Gil Otherwise, it looks good to me. Reviewed-by: Chao Yu Thanks, > --- > fs/f2fs/data.c | 12 ++++++++++-- > 1 file changed, 10 insertions(+), 2 deletions(-) > > diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c > index 2e133a723b99..11c262afad65 100644 > --- a/fs/f2fs/data.c > +++ b/fs/f2fs/data.c > @@ -1851,7 +1851,8 @@ int f2fs_map_blocks(struct inode *inode, struct f2fs_map_blocks *map, int flag) > return err; > } > > -bool f2fs_overwrite_io(struct inode *inode, loff_t pos, size_t len) > +static bool __f2fs_overwrite_io(struct inode *inode, loff_t pos, size_t len, > + bool check_first) > { > struct f2fs_map_blocks map; > block_t last_lblk; > @@ -1873,10 +1874,17 @@ bool f2fs_overwrite_io(struct inode *inode, loff_t pos, size_t len) > if (err || map.m_len == 0) > return false; > map.m_lblk += map.m_len; > + if (check_first) > + break; > } > return true; > } > > +bool f2fs_overwrite_io(struct inode *inode, loff_t pos, size_t len) > +{ > + return __f2fs_overwrite_io(inode, pos, len, false); > +} > + > static int f2fs_xattr_fiemap(struct inode *inode, > struct fiemap_extent_info *fieinfo) > { > @@ -4443,7 +4451,7 @@ static int f2fs_iomap_begin(struct inode *inode, loff_t offset, loff_t length, > * f2fs_map_lock and f2fs_balance_fs are not necessary. > */ > if ((flags & IOMAP_WRITE) && > - !f2fs_overwrite_io(inode, offset, length)) > + !__f2fs_overwrite_io(inode, offset, length, true)) > map.m_may_create = true; > > err = f2fs_map_blocks(inode, &map, F2FS_GET_BLOCK_DIO);