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 68EC617728 for ; Tue, 2 Jan 2024 22:54:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="rXIgUSAJ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id AF529C433C8; Tue, 2 Jan 2024 22:54:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1704236072; bh=BDXXal94Su2uaDJCUkGS/5w9XDeM8Wk9XYBMyM7Nyy8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=rXIgUSAJIPast68Xs9QUwtAwEb5+BSCr0TB1o421tQFL8+5pnfBL1zyQa6b9v9egD 3OtmvJtck58DraxnNCz4+sbVzG/n/crMV/TeApm0tS+7MBFBEFhe+6FV7+YERN5ggb O9duCK94c/aiKjVE6EmgUCFcthIM8pEVIdrObN/JBVT9qMjkwqs3Ml1jA2A+0k5pK7 136xGm69qonnce23kOtiZjXXbpGHVSx8sLEzkGGbaLRKERbD0b19NarsLRDaogT3qI +Qdv7c6W59mlzJuzA0TsDff2dBCHdGWSVKuFgVCleyCQo6S0gxFNuPGDshRh5Qsvo/ FSVgUYqNGJ8XA== Date: Tue, 2 Jan 2024 14:54:31 -0800 From: Jaegeuk Kim To: Chao Yu Cc: linux-f2fs-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org Subject: Re: [PATCH 5/6] f2fs: fix to restrict condition of compress inode conversion Message-ID: 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> 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: <19a1340f-0a0d-40a0-9d00-0faf171480f2@kernel.org> 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? > > 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