Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Date:   Mon, 24 May 2021 18:45:31 -0700
From:   Jaegeuk Kim <jaegeuk@kernel.org>
To:     Chao Yu <yuchao0@huawei.com>
Cc:     linux-kernel@vger.kernel.org,
        linux-f2fs-devel@lists.sourceforge.net
Subject: Re: [f2fs-dev] [PATCH 2/2] f2fs: support RO feature
Message-ID: <YKxWu9G3GfRO+fGX@google.com>
References: <20210521190217.2484099-1-jaegeuk@kernel.org>
 <20210521190217.2484099-2-jaegeuk@kernel.org>
 <b1647bd1-f719-5796-4f99-766f0bc66d49@huawei.com>
 <YKvdQbA1+kdD3jQC@google.com>
 <52bf2f86-58c3-c012-9f73-d34fcd7dd3a8@huawei.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <52bf2f86-58c3-c012-9f73-d34fcd7dd3a8@huawei.com>
Precedence: bulk

On 05/25, Chao Yu wrote:
> On 2021/5/25 1:07, Jaegeuk Kim wrote:
> > On 05/24, Chao Yu wrote:
> > > On 2021/5/22 3:02, Jaegeuk Kim wrote:
> > > > Given RO feature in superblock, we don't need to check provisioning/reserve
> > > > spaces and SSA area.
> > > 
> > > Cool, any solution to update files of ro f2fs image if there is such
> > > scenario?
> > 
> > Hmm, overlayfs?
> 
> I mean using f2fs-tools, maybe...

sload.f2fs supports it with this patch?

https://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs-tools.git/commit/?h=dev&id=9069b6b6f17faa66c8546567882b2e66bc78b8eb

> 
> Thanks,
> 
> > 
> > > 
> > > > 
> > > > Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
> > > > ---
> > > >    fs/f2fs/f2fs.h    |  2 ++
> > > >    fs/f2fs/segment.c |  3 +++
> > > >    fs/f2fs/super.c   | 35 +++++++++++++++++++++++++++++++----
> > > >    3 files changed, 36 insertions(+), 4 deletions(-)
> > > > 
> > > > diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> > > > index c0bead0df66a..2c6913261586 100644
> > > > --- a/fs/f2fs/f2fs.h
> > > > +++ b/fs/f2fs/f2fs.h
> > > > @@ -168,6 +168,7 @@ struct f2fs_mount_info {
> > > >    #define F2FS_FEATURE_SB_CHKSUM		0x0800
> > > >    #define F2FS_FEATURE_CASEFOLD		0x1000
> > > >    #define F2FS_FEATURE_COMPRESSION	0x2000
> > > > +#define F2FS_FEATURE_RO			0x4000
> > > >    #define __F2FS_HAS_FEATURE(raw_super, mask)				\
> > > >    	((raw_super->feature & cpu_to_le32(mask)) != 0)
> > > > @@ -939,6 +940,7 @@ static inline void set_new_dnode(struct dnode_of_data *dn, struct inode *inode,
> > > >    #define	NR_CURSEG_DATA_TYPE	(3)
> > > >    #define NR_CURSEG_NODE_TYPE	(3)
> > > >    #define NR_CURSEG_INMEM_TYPE	(2)
> > > > +#define NR_CURSEG_RO_TYPE	(2)
> > > >    #define NR_CURSEG_PERSIST_TYPE	(NR_CURSEG_DATA_TYPE + NR_CURSEG_NODE_TYPE)
> > > >    #define NR_CURSEG_TYPE		(NR_CURSEG_INMEM_TYPE + NR_CURSEG_PERSIST_TYPE)
> > > > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> > > > index 8668df7870d0..67cec8f858a2 100644
> > > > --- a/fs/f2fs/segment.c
> > > > +++ b/fs/f2fs/segment.c
> > > > @@ -4674,6 +4674,9 @@ static int sanity_check_curseg(struct f2fs_sb_info *sbi)
> > > >    {
> > > >    	int i;
> > > > +	if (__F2FS_HAS_FEATURE(sbi->raw_super, F2FS_FEATURE_RO))
> > > 
> > > Why not using F2FS_HAS_FEATURE(sbi, F2FS_FEATURE_RO))?
> > 
> > Oh, updated.
> > 
> > > 
> > > Ditto for all below __F2FS_HAS_FEATURE().
> > > 
> > > Thanks,
> > > 
> > > > +		return 0;
> > > > +
> > > >    	/*
> > > >    	 * In LFS/SSR curseg, .next_blkoff should point to an unused blkaddr;
> > > >    	 * In LFS curseg, all blkaddr after .next_blkoff should be unused.
> > > > diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
> > > > index b29de80ab60e..312bfab54693 100644
> > > > --- a/fs/f2fs/super.c
> > > > +++ b/fs/f2fs/super.c
> > > > @@ -1819,7 +1819,11 @@ static int f2fs_show_options(struct seq_file *seq, struct dentry *root)
> > > >    static void default_options(struct f2fs_sb_info *sbi)
> > > >    {
> > > >    	/* init some FS parameters */
> > > > -	F2FS_OPTION(sbi).active_logs = NR_CURSEG_PERSIST_TYPE;
> > > > +	if (__F2FS_HAS_FEATURE(sbi->raw_super, F2FS_FEATURE_RO))
> > > > +		F2FS_OPTION(sbi).active_logs = NR_CURSEG_RO_TYPE;
> > > > +	else
> > > > +		F2FS_OPTION(sbi).active_logs = NR_CURSEG_PERSIST_TYPE;
> > > > +
> > > >    	F2FS_OPTION(sbi).inline_xattr_size = DEFAULT_INLINE_XATTR_ADDRS;
> > > >    	F2FS_OPTION(sbi).whint_mode = WHINT_MODE_OFF;
> > > >    	F2FS_OPTION(sbi).alloc_mode = ALLOC_MODE_DEFAULT;
> > > > @@ -1994,6 +1998,11 @@ static int f2fs_remount(struct super_block *sb, int *flags, char *data)
> > > >    	err = parse_options(sb, data, true);
> > > >    	if (err)
> > > >    		goto restore_opts;
> > > > +
> > > > +	if (__F2FS_HAS_FEATURE(sbi->raw_super, F2FS_FEATURE_RO) &&
> > > > +					!(*flags & SB_RDONLY))
> > > > +		goto restore_opts;
> > > > +
> > > >    	checkpoint_changed =
> > > >    			disable_checkpoint != test_opt(sbi, DISABLE_CHECKPOINT);
> > > > @@ -3137,16 +3146,18 @@ int f2fs_sanity_check_ckpt(struct f2fs_sb_info *sbi)
> > > >    	ovp_segments = le32_to_cpu(ckpt->overprov_segment_count);
> > > >    	reserved_segments = le32_to_cpu(ckpt->rsvd_segment_count);
> > > > +	if (__F2FS_HAS_FEATURE(sbi->raw_super, F2FS_FEATURE_RO))
> > > > +		goto no_reserved;
> > > >    	if (unlikely(fsmeta < F2FS_MIN_META_SEGMENTS ||
> > > >    			ovp_segments == 0 || reserved_segments == 0)) {
> > > >    		f2fs_err(sbi, "Wrong layout: check mkfs.f2fs version");
> > > >    		return 1;
> > > >    	}
> > > > -
> > > > +no_reserved:
> > > >    	user_block_count = le64_to_cpu(ckpt->user_block_count);
> > > >    	segment_count_main = le32_to_cpu(raw_super->segment_count_main);
> > > >    	log_blocks_per_seg = le32_to_cpu(raw_super->log_blocks_per_seg);
> > > > -	if (!user_block_count || user_block_count >=
> > > > +	if (!user_block_count || user_block_count >
> > > >    			segment_count_main << log_blocks_per_seg) {
> > > >    		f2fs_err(sbi, "Wrong user_block_count: %u",
> > > >    			 user_block_count);
> > > > @@ -3175,6 +3186,10 @@ int f2fs_sanity_check_ckpt(struct f2fs_sb_info *sbi)
> > > >    		if (le32_to_cpu(ckpt->cur_node_segno[i]) >= main_segs ||
> > > >    			le16_to_cpu(ckpt->cur_node_blkoff[i]) >= blocks_per_seg)
> > > >    			return 1;
> > > > +
> > > > +		if (__F2FS_HAS_FEATURE(sbi->raw_super, F2FS_FEATURE_RO))
> > > > +			goto check_data;
> > > > +
> > > >    		for (j = i + 1; j < NR_CURSEG_NODE_TYPE; j++) {
> > > >    			if (le32_to_cpu(ckpt->cur_node_segno[i]) ==
> > > >    				le32_to_cpu(ckpt->cur_node_segno[j])) {
> > > > @@ -3185,10 +3200,15 @@ int f2fs_sanity_check_ckpt(struct f2fs_sb_info *sbi)
> > > >    			}
> > > >    		}
> > > >    	}
> > > > +check_data:
> > > >    	for (i = 0; i < NR_CURSEG_DATA_TYPE; i++) {
> > > >    		if (le32_to_cpu(ckpt->cur_data_segno[i]) >= main_segs ||
> > > >    			le16_to_cpu(ckpt->cur_data_blkoff[i]) >= blocks_per_seg)
> > > >    			return 1;
> > > > +
> > > > +		if (__F2FS_HAS_FEATURE(sbi->raw_super, F2FS_FEATURE_RO))
> > > > +			goto skip_cross;
> > > > +
> > > >    		for (j = i + 1; j < NR_CURSEG_DATA_TYPE; j++) {
> > > >    			if (le32_to_cpu(ckpt->cur_data_segno[i]) ==
> > > >    				le32_to_cpu(ckpt->cur_data_segno[j])) {
> > > > @@ -3210,7 +3230,7 @@ int f2fs_sanity_check_ckpt(struct f2fs_sb_info *sbi)
> > > >    			}
> > > >    		}
> > > >    	}
> > > > -
> > > > +skip_cross:
> > > >    	sit_bitmap_size = le32_to_cpu(ckpt->sit_ver_bitmap_bytesize);
> > > >    	nat_bitmap_size = le32_to_cpu(ckpt->nat_ver_bitmap_bytesize);
> > > > @@ -3703,6 +3723,13 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
> > > >    	if (err)
> > > >    		goto free_options;
> > > > +	if (__F2FS_HAS_FEATURE(sbi->raw_super, F2FS_FEATURE_RO) &&
> > > > +					!f2fs_readonly(sbi->sb)) {
> > > > +		f2fs_info(sbi, "Allow to mount readonly mode only");
> > > > +		err = -EINVAL;
> > > > +		goto free_options;
> > > > +	}
> > > > +
> > > >    	sb->s_maxbytes = max_file_blocks(NULL) <<
> > > >    				le32_to_cpu(raw_super->log_blocksize);
> > > >    	sb->s_max_links = F2FS_LINK_MAX;
> > > > 
> > .
> >