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 18442768EF for ; Mon, 29 Jul 2024 02:54:51 +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=1722221692; cv=none; b=Xqug7gtLdSc8cRFnIwBCANw1hYgA1om0wCl23ztnIZIfy62CaOyEKyNE0owRX1vJsBnoVlL/vEer1h9a0Qz/0HWT7c/AeinKmWXPiWequIuaK5yCEQBUtVrYv+0p71RZH4hBUiNbGdSD936w/yqO1pWw6gIIGsaw9mmk3wvd8Rs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722221692; c=relaxed/simple; bh=CxoLcnEcwOVtU1sK4vdRlZkJkyUaqBQg4RZqDYGsewc=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=C6uUTU2PbSBiBcsUBMh0RQ6+rT6ZrzvbupPcQVqQEIUUv8j1qKqUTd7NjqW6eXkRC1UyJHmgRtVtccXmdFUh/T7O0I5g1CfqaBBSzch1t6TqEplrAx0HkJA0cnkqYiuCvrAanERtKMnTwhKaM2bJWGPvECiNdxhLJ5T4Vkp3bVE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=t+3HO33a; 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="t+3HO33a" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CBA7BC116B1; Mon, 29 Jul 2024 02:54:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1722221691; bh=CxoLcnEcwOVtU1sK4vdRlZkJkyUaqBQg4RZqDYGsewc=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=t+3HO33axhe4bI77zQ7MMUu9NHRW2zqAhWCzNCGNupsn9Xqru9T7dLBfxCJXuDhLg xW5vS/sN/7jlZe+hWiTzDkmBgZFOqDxM4LhoImfgz/+RTdvnfk4pif3yk0Lmzu1moW dDZQJjkDQ1juI1cWVrO4+W6ZVPGhLo34mXn53tteyCtjx1Zqb6GbWDvhnAWF9eucBY Z46hGqzKls8vSZks2XGCLNo0DEUheNEr/goct9SySfk6Q4NuXLav5hQYfbDY/aAwFu fg8Tx/R2XukD+mQQIryc6nTGSgRB3vcSoj2yf9m+7ks2Pcl9Ttqnbe6+mAFhjp4m6K IYNJNt08u7rtg== Message-ID: <74dbb5f1-1565-4971-ae5c-c176d62cfa8f@kernel.org> Date: Mon, 29 Jul 2024 10:54:46 +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 Subject: Re: [PATCH] f2fs: don't traverse directory blocks after EOF To: Jaegeuk Kim Cc: linux-f2fs-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org References: <20240712073415.227226-1-chao@kernel.org> Content-Language: en-US From: Chao Yu In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 2024/7/27 11:27, Jaegeuk Kim wrote: > On 07/26, Chao Yu wrote: >> On 2024/7/26 0:55, Jaegeuk Kim wrote: >>> On 07/12, Chao Yu wrote: >>>> All directory blocks are within the scope of i_size, so let's limit >>>> the end_block to just check valid dirent blocks. >>> >>> Do we really need this? >> >> f2fs_readdir() and f2fs_empty_dir() uses dir_blocks() for upper boundary, >> this patch aligns find_in_level() w/ them. >> >> Also, it can avoid grabbing never used page cache across EOF. >> >> So, we can consider taking this patch? > > I'm wondering whether the current code has a bug or not. I think it's not a bug, but, in corner case it may waste memory and cause a bit performance reduction. Thanks, > >> >> Thanks, >> >>> >>>> >>>> Meanwhile, it uses dir_blocks() instead of variable for cleanup in >>>> __f2fs_find_entry(). >>>> >>>> Signed-off-by: Chao Yu >>>> --- >>>> fs/f2fs/dir.c | 6 ++++-- >>>> 1 file changed, 4 insertions(+), 2 deletions(-) >>>> >>>> diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c >>>> index 02c9355176d3..d4591c215f07 100644 >>>> --- a/fs/f2fs/dir.c >>>> +++ b/fs/f2fs/dir.c >>>> @@ -305,18 +305,21 @@ static struct f2fs_dir_entry *find_in_level(struct inode *dir, >>>> int s = GET_DENTRY_SLOTS(fname->disk_name.len); >>>> unsigned int nbucket, nblock; >>>> unsigned int bidx, end_block; >>>> + unsigned long last_block; >>>> struct page *dentry_page; >>>> struct f2fs_dir_entry *de = NULL; >>>> pgoff_t next_pgofs; >>>> bool room = false; >>>> int max_slots; >>>> + last_block = dir_blocks(dir); >>>> nbucket = dir_buckets(level, F2FS_I(dir)->i_dir_level); >>>> nblock = bucket_blocks(level); >>>> bidx = dir_block_index(level, F2FS_I(dir)->i_dir_level, >>>> le32_to_cpu(fname->hash) % nbucket); >>>> end_block = bidx + nblock; >>>> + end_block = min_t(unsigned int, end_block, last_block); >>>> while (bidx < end_block) { >>>> /* no need to allocate new dentry pages to all the indices */ >>>> @@ -361,7 +364,6 @@ struct f2fs_dir_entry *__f2fs_find_entry(struct inode *dir, >>>> const struct f2fs_filename *fname, >>>> struct page **res_page) >>>> { >>>> - unsigned long npages = dir_blocks(dir); >>>> struct f2fs_dir_entry *de = NULL; >>>> unsigned int max_depth; >>>> unsigned int level; >>>> @@ -373,7 +375,7 @@ struct f2fs_dir_entry *__f2fs_find_entry(struct inode *dir, >>>> goto out; >>>> } >>>> - if (npages == 0) >>>> + if (dir_blocks(dir) == 0) >>>> goto out; >>>> max_depth = F2FS_I(dir)->i_current_depth; >>>> -- >>>> 2.40.1