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 E37DEA4A for ; Thu, 11 Jan 2024 03:07:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="gnIQb8SA" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7D179C433C7; Thu, 11 Jan 2024 03:07:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1704942448; bh=rvYGrz5r6RFIIcCmbdTuHKZhgc1jaytowl3Yu/VDpEs=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=gnIQb8SAiRcMuQ/Mhy5vDEiogZqECL0yXbnYoxyP26XWU0UApDHCJlN0Ea6piO9qP bXfzLZ2IWT+xjGnJMuQ6jE066Puc4mQljlQx3lSeSrbPXmnHgKD2sbjUD4hOuTnrr+ Gakr9ceHXCdZiwfHkdgun05tvddSBjyv+hmVgjoUbe4/pDnce4+kNtPPDjeIzJ03M/ xtiWDI7dpI1x1G0R741zZBj1txCGMXESNDfOA8fR+7JnvAMLtRV6u7P2xJrjxRSN/q twyNLpvrsiXytQFf3cpAV7iYOnUhk/g8oEF/thIAVz8vKXoVd5HGNX3IkVtd+is1rL 1i/20uLpY+UBw== Message-ID: Date: Thu, 11 Jan 2024 11:07:24 +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 5/6] f2fs: fix to restrict condition of compress inode conversion Content-Language: en-US To: Jaegeuk Kim Cc: linux-f2fs-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org References: <20231210113547.3412782-1-chao@kernel.org> <20231210113547.3412782-5-chao@kernel.org> <5884e300-5384-4a49-9f8d-8cced50f4e6d@kernel.org> <19a1340f-0a0d-40a0-9d00-0faf171480f2@kernel.org> From: Chao Yu In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 2024/1/3 6:54, Jaegeuk Kim wrote: > On 12/28, Chao Yu wrote: >> On 2023/12/13 6:21, Jaegeuk Kim wrote: >>> On 12/12, Chao Yu wrote: >>>> On 2023/12/12 6:11, Jaegeuk Kim wrote: >>>>> On 12/10, Chao Yu wrote: >>>>>> This patch adds i_size check during compress inode conversion in order >>>>>> to avoid .page_mkwrite races w/ conversion. >>>>> >>>>> Which race condition do you see? >>>> >>>> Something like: >>>> >>>> - f2fs_setflags_common >>>> - check S_ISREG && F2FS_HAS_BLOCKS >>>> - mkwrite >>>> - f2fs_get_block_locked >>>> : update metadata in old inode's disk layout >>> >>> Don't we need to prevent setting this for mmapped file? >> >> Oh, we have used i_sem lock to prevent such race case, however >> we missed f2fs_disable_compressed_file(): >> >> - f2fs_disable_compressed_file >> - check inode_has_data >> - f2fs_file_mmap >> - mkwrite >> - f2fs_get_block_locked >> : update metadata in compressed >> inode's disk layout >> - fi->i_flags &= ~F2FS_COMPR_FL >> - clear_inode_flag(inode, FI_COMPRESSED_FILE); > > So, needing i_sem for disabling it on mmapped file? It seems i_size would not > be enough? Agreed, let me update the patch. Thanks, > >> >> Thanks, >> >>> >>>> - set_compress_context >>>> >>>> Thanks, >>>> >>>>> >>>>>> >>>>>> Fixes: 4c8ff7095bef ("f2fs: support data compression") >>>>>> Signed-off-by: Chao Yu >>>>>> --- >>>>>> fs/f2fs/f2fs.h | 8 +++++++- >>>>>> fs/f2fs/file.c | 5 ++--- >>>>>> 2 files changed, 9 insertions(+), 4 deletions(-) >>>>>> >>>>>> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h >>>>>> index 65294e3b0bef..c9b8a1953913 100644 >>>>>> --- a/fs/f2fs/f2fs.h >>>>>> +++ b/fs/f2fs/f2fs.h >>>>>> @@ -4397,13 +4397,19 @@ static inline int set_compress_context(struct inode *inode) >>>>>> #endif >>>>>> } >>>>>> +static inline bool inode_has_data(struct inode *inode) >>>>>> +{ >>>>>> + return (S_ISREG(inode->i_mode) && >>>>>> + (F2FS_HAS_BLOCKS(inode) || i_size_read(inode))); >>>>>> +} >>>>>> + >>>>>> static inline bool f2fs_disable_compressed_file(struct inode *inode) >>>>>> { >>>>>> struct f2fs_inode_info *fi = F2FS_I(inode); >>>>>> if (!f2fs_compressed_file(inode)) >>>>>> return true; >>>>>> - if (S_ISREG(inode->i_mode) && F2FS_HAS_BLOCKS(inode)) >>>>>> + if (inode_has_data(inode)) >>>>>> return false; >>>>>> fi->i_flags &= ~F2FS_COMPR_FL; >>>>>> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c >>>>>> index 1a3c29a9a6a0..8af4b29c3e1a 100644 >>>>>> --- a/fs/f2fs/file.c >>>>>> +++ b/fs/f2fs/file.c >>>>>> @@ -1922,8 +1922,7 @@ static int f2fs_setflags_common(struct inode *inode, u32 iflags, u32 mask) >>>>>> f2fs_down_write(&F2FS_I(inode)->i_sem); >>>>>> if (!f2fs_may_compress(inode) || >>>>>> - (S_ISREG(inode->i_mode) && >>>>>> - F2FS_HAS_BLOCKS(inode))) { >>>>>> + inode_has_data(inode)) { >>>>>> f2fs_up_write(&F2FS_I(inode)->i_sem); >>>>>> return -EINVAL; >>>>>> } >>>>>> @@ -3996,7 +3995,7 @@ static int f2fs_ioc_set_compress_option(struct file *filp, unsigned long arg) >>>>>> goto out; >>>>>> } >>>>>> - if (F2FS_HAS_BLOCKS(inode)) { >>>>>> + if (inode_has_data(inode)) { >>>>>> ret = -EFBIG; >>>>>> goto out; >>>>>> } >>>>>> -- >>>>>> 2.40.1