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Date:   Tue, 30 Apr 2019 20:22:42 -0700
From:   Jaegeuk Kim <jaegeuk@kernel.org>
To:     Chao Yu <chao@kernel.org>
Cc:     Chao Yu <yuchao0@huawei.com>,
        linux-f2fs-devel@lists.sourceforge.net,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH] f2fs: fix to do sanity with enabled features in image
Message-ID: <20190501032242.GA84420@jaegeuk-macbookpro.roam.corp.google.com>
References: <20190424094850.118323-1-yuchao0@huawei.com>
 <20190428133802.GB37346@jaegeuk-macbookpro.roam.corp.google.com>
 <373f4633-d331-5cf3-74b7-e982072bc4b4@kernel.org>
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On 04/29, Chao Yu wrote:
> On 2019-4-28 21:38, Jaegeuk Kim wrote:
> > On 04/24, Chao Yu wrote:
> >> This patch fixes to do sanity with enabled features in image, if
> >> there are features kernel can not recognize, just fail the mount.
> > 
> > We need to figure out per-feature-based rejection, since some of them can
> > be set without layout change.
> 
> So any suggestion on how to implement this?

Which features do we need to disallow? When we introduce new features, they
didn't hurt the previous flow by checking f2fs_sb_has_###().

> 
> Maybe:
> 
> if (LINUX_VERSION_CODE < KERNEL_VERSION(4, 14, 0))
> 	check 4.14+ features
> else if (LINUX_VERSION_CODE < KERNEL_VERSION(4, 9, 0))
> 	check 4.9+ features
> else if (LINUX_VERSION_CODE < KERNEL_VERSION(4, 4, 0))
> 	check 4.4+ features
> 
> Thanks,
> 
> > 
> >>
> >> Signed-off-by: Chao Yu <yuchao0@huawei.com>
> >> ---
> >>  fs/f2fs/f2fs.h  | 13 +++++++++++++
> >>  fs/f2fs/super.c |  9 +++++++++
> >>  2 files changed, 22 insertions(+)
> >>
> >> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> >> index f5ffc09705eb..15b640967e12 100644
> >> --- a/fs/f2fs/f2fs.h
> >> +++ b/fs/f2fs/f2fs.h
> >> @@ -151,6 +151,19 @@ struct f2fs_mount_info {
> >>  #define F2FS_FEATURE_VERITY		0x0400	/* reserved */
> >>  #define F2FS_FEATURE_SB_CHKSUM		0x0800
> >>  
> >> +#define F2FS_ALL_FEATURES	(F2FS_FEATURE_ENCRYPT |			\
> >> +				F2FS_FEATURE_BLKZONED |			\
> >> +				F2FS_FEATURE_ATOMIC_WRITE |		\
> >> +				F2FS_FEATURE_EXTRA_ATTR |		\
> >> +				F2FS_FEATURE_PRJQUOTA |			\
> >> +				F2FS_FEATURE_INODE_CHKSUM |		\
> >> +				F2FS_FEATURE_FLEXIBLE_INLINE_XATTR |	\
> >> +				F2FS_FEATURE_QUOTA_INO |		\
> >> +				F2FS_FEATURE_INODE_CRTIME |		\
> >> +				F2FS_FEATURE_LOST_FOUND |		\
> >> +				F2FS_FEATURE_VERITY |			\
> >> +				F2FS_FEATURE_SB_CHKSUM)
> >> +
> >>  #define __F2FS_HAS_FEATURE(raw_super, mask)				\
> >>  	((raw_super->feature & cpu_to_le32(mask)) != 0)
> >>  #define F2FS_HAS_FEATURE(sbi, mask)	__F2FS_HAS_FEATURE(sbi->raw_super, mask)
> >> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
> >> index 4f8e9ab48b26..57f2fc6d14ba 100644
> >> --- a/fs/f2fs/super.c
> >> +++ b/fs/f2fs/super.c
> >> @@ -2573,6 +2573,15 @@ static int sanity_check_raw_super(struct f2fs_sb_info *sbi,
> >>  		return 1;
> >>  	}
> >>  
> >> +	/* check whether kernel supports all features */
> >> +	if (le32_to_cpu(raw_super->feature) & (~F2FS_ALL_FEATURES)) {
> >> +		f2fs_msg(sb, KERN_INFO,
> >> +			"Unsupported feature:%u: supported:%u",
> >> +			le32_to_cpu(raw_super->feature),
> >> +			F2FS_ALL_FEATURES);
> >> +		return 1;
> >> +	}
> >> +
> >>  	/* check CP/SIT/NAT/SSA/MAIN_AREA area boundary */
> >>  	if (sanity_check_area_boundary(sbi, bh))
> >>  		return 1;
> >> -- 
> >> 2.18.0.rc1