linux-kernel - Re: [PATCH] f2fs: fix to remove F2FS_COMPR_FL and tag F2FS_NOCOMP

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Message-ID: <0771b00b-e781-cd29-896a-4b6ebc948c2e@kernel.org>
Date:   Wed, 22 Jun 2022 21:42:13 +0800
From:   Chao Yu <chao@...nel.org>
To:     Chao Liu <chaoliu719@...il.com>, Jaegeuk Kim <jaegeuk@...nel.org>
Cc:     linux-f2fs-devel@...ts.sourceforge.net,
        linux-kernel@...r.kernel.org, Yue Hu <huyue2@...lpad.com>,
        Wayne Zhang <zhangwen@...lpad.com>,
        Xiaoyu Qi <qxy65535@...il.com>, Chao Liu <liuchao@...lpad.com>
Subject: Re: [PATCH] f2fs: fix to remove F2FS_COMPR_FL and tag F2FS_NOCOMP_FL
 at the same time

On 2022/6/21 14:48, Chao Liu wrote:
> From: Chao Liu <liuchao@...lpad.com>
> 
> If the inode has the compress flag, it will fail to use
> 'chattr -c +m' to remove its compress flag and tag no compress flag.
> However, the same command will be successful when executed again,
> as shown below:
> 
>    $ touch foo.txt
>    $ chattr +c foo.txt
>    $ chattr -c +m foo.txt
>    chattr: Invalid argument while setting flags on foo.txt
>    $ chattr -c +m foo.txt
>    $ f2fs_io getflags foo.txt
>    get a flag on foo.txt ret=0, flags=nocompression,inline_data
> 
> Fix this by removing some checks in f2fs_setflags_common()
> that do not affect the original logic. I go through all the
> possible scenarios, and the results are as follows. Bold is
> the only thing that has changed.
> 
> +---------------+-----------+-----------+----------+
> |               |            file flags            |
> + command       +-----------+-----------+----------+
> |               | no flag   | compr     | nocompr  |
> +---------------+-----------+-----------+----------+
> | chattr +c     | compr     | compr     | -EINVAL  |
> | chattr -c     | no flag   | no flag   | nocompr  |
> | chattr +m     | nocompr   | -EINVAL   | nocompr  |
> | chattr -m     | no flag   | compr     | no flag  |
> | chattr +c +m  | -EINVAL   | -EINVAL   | -EINVAL  |
> | chattr +c -m  | compr     | compr     | compr    |
> | chattr -c +m  | nocompr   | *nocompr* | nocompr  |
> | chattr -c -m  | no flag   | no flag   | no flag  |
> +---------------+-----------+-----------+----------+
> 
> Fixes: 4c8ff7095bef ("f2fs: support data compression")
> Signed-off-by: Chao Liu <liuchao@...lpad.com>
> ---
> 
> This patch depends on the the patch
> "f2fs: allow compression of files without blocks" sent earlier this day.
> 
>   fs/f2fs/file.c | 9 +--------
>   1 file changed, 1 insertion(+), 8 deletions(-)
> 
> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> index daaa0dfd2d2e..0c3ae5993b7a 100644
> --- a/fs/f2fs/file.c
> +++ b/fs/f2fs/file.c
> @@ -1873,10 +1873,7 @@ static int f2fs_setflags_common(struct inode *inode, u32 iflags, u32 mask)
>   		if (masked_flags & F2FS_COMPR_FL) {
>   			if (!f2fs_disable_compressed_file(inode))
>   				return -EINVAL;
> -		}
> -		if (iflags & F2FS_NOCOMP_FL)
> -			return -EINVAL;
> -		if (iflags & F2FS_COMPR_FL) {
> +		} else {
>   			if (!f2fs_may_compress(inode))
>   				return -EINVAL;
>   			if (S_ISREG(inode->i_mode) && F2FS_HAS_BLOCKS(inode))
> @@ -1885,10 +1882,6 @@ static int f2fs_setflags_common(struct inode *inode, u32 iflags, u32 mask)
>   			set_compress_context(inode);
>   		}
>   	}
> -	if ((iflags ^ masked_flags) & F2FS_NOCOMP_FL) {
> -		if (masked_flags & F2FS_COMPR_FL)
> -			return -EINVAL;
> -	}

Without above check condition, can we return -EINVAL for the case:

chattr +c on file w/ nocompr flag

|               | no flag   | compr     | nocompr  |
+---------------+-----------+-----------+----------+
| chattr +c     | compr     | compr     | *-EINVAL*  |

Thanks,

> 
>   	fi->i_flags = iflags | (fi->i_flags & ~mask);
>   	f2fs_bug_on(F2FS_I_SB(inode), (fi->i_flags & F2FS_COMPR_FL) &&
> --
> 2.36.1