Date:   Mon, 1 Mar 2021 20:25:35 -0800
From:   Jaegeuk Kim <jaegeuk@...nel.org>
To:     Chao Yu <yuchao0@...wei.com>
Cc:     linux-kernel@...r.kernel.org,
        linux-f2fs-devel@...ts.sourceforge.net, zhangshiming@...o.com
Subject: Re: [f2fs-dev] [PATCH 3/3] f2fs: check if swapfile is
 section-alligned

On 03/01, Jaegeuk Kim wrote:
> On 03/01, Chao Yu wrote:
> > Hi Jianan,
> 
> Merged 1/3 and 2/3, so please post v2 on 3/3.

NVM. Found v2.

> 
> Thanks,
> 
> > 
> > On 2021/2/27 20:02, Huang Jianan via Linux-f2fs-devel wrote:
> > > If the swapfile isn't created by pin and fallocate, it cann't be
> > 
> > Typo:
> > 
> > can't
> > 
> > > guaranteed section-aligned, so it may be selected by f2fs gc. When
> > > gc_pin_file_threshold is reached, the address of swapfile may change,
> > > but won't be synchroniz to swap_extent, so swap will write to wrong
> > 
> > synchronized
> > 
> > > address, which will cause data corruption.
> > > 
> > > Signed-off-by: Huang Jianan <huangjianan@...o.com>
> > > Signed-off-by: Guo Weichao <guoweichao@...o.com>
> > > ---
> > >   fs/f2fs/data.c | 63 ++++++++++++++++++++++++++++++++++++++++++++++++++
> > >   1 file changed, 63 insertions(+)
> > > 
> > > diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> > > index 4dbc1cafc55d..3e523d6e4643 100644
> > > --- a/fs/f2fs/data.c
> > > +++ b/fs/f2fs/data.c
> > > @@ -3781,11 +3781,63 @@ int f2fs_migrate_page(struct address_space *mapping,
> > >   #endif
> > >   #ifdef CONFIG_SWAP
> > > +static int f2fs_check_file_aligned(struct inode *inode)
> > 
> > f2fs_check_file_alignment() or f2fs_is_file_aligned()?
> > 
> > > +{
> > > +	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
> > > +	block_t main_blkaddr = SM_I(sbi)->main_blkaddr;
> > > +	block_t cur_lblock;
> > > +	block_t last_lblock;
> > > +	block_t pblock;
> > > +	unsigned long len;
> > > +	unsigned long nr_pblocks;
> > > +	unsigned int blocks_per_sec = sbi->blocks_per_seg * sbi->segs_per_sec;
> > 
> > unsigned int blocks_per_sec = BLKS_PER_SEC(sbi);
> > 
> > > +	int ret;
> > > +
> > > +	cur_lblock = 0;
> > > +	last_lblock = bytes_to_blks(inode, i_size_read(inode));
> > > +	len = i_size_read(inode);
> > > +
> > > +	while (cur_lblock < last_lblock) {
> > > +		struct f2fs_map_blocks map;
> > > +		pgoff_t next_pgofs;
> > > +
> > > +		memset(&map, 0, sizeof(map));
> > > +		map.m_lblk = cur_lblock;
> > > +		map.m_len = bytes_to_blks(inode, len) - cur_lblock;
> > 
> > map.m_len = last_lblock - cur_lblock;
> > 
> > > +		map.m_next_pgofs = &next_pgofs;
> > 
> > map.m_next_pgofs = NULL;
> > map.m_next_extent = NULL;
> > 
> > > +		map.m_seg_type = NO_CHECK_TYPE;
> > 
> > map.m_may_create = false;
> > 
> > > +
> > > +		ret = f2fs_map_blocks(inode, &map, 0, F2FS_GET_BLOCK_FIEMAP);
> > > +
> > 
> > Unneeded blank line.
> > 
> > > +		if (ret)
> > > +			goto err_out;
> > > +
> > > +		/* hole */
> > > +		if (!(map.m_flags & F2FS_MAP_FLAGS))
> > 
> > ret = -ENOENT;
> > 
> > > +			goto err_out;
> > > +
> > > +		pblock = map.m_pblk;
> > > +		nr_pblocks = map.m_len;
> > > +
> > > +		if ((pblock - main_blkaddr) & (blocks_per_sec - 1) ||
> > > +			nr_pblocks & (blocks_per_sec - 1))
> > 
> > ret = -EINVAL;
> > 
> > > +			goto err_out;
> > > +
> > > +		cur_lblock += nr_pblocks;
> > > +	}
> > > +
> > > +	return 0;
> > > +err_out:
> > > +	pr_err("swapon: swapfile isn't section-aligned\n");
> > 
> > We should show above message only after we fail in check condition:
> > 
> > 	if ((pblock - main_blkaddr) & (blocks_per_sec - 1) ||
> > 		nr_pblocks & (blocks_per_sec - 1)) {
> > 		f2fs_err(sbi, "Swapfile does not align to section");
> > 		goto err_out;
> > 	}
> > 
> > And please use f2fs_{err,warn,info..} macro rather than pr_{err,warn,info..}.
> > 
> > Could you please fix above related issues in check_swap_activate_fast() as well.
> > 
> > > +	return -EINVAL;
> > 
> > return ret;
> > 
> > > +}
> > > +
> > >   static int check_swap_activate_fast(struct swap_info_struct *sis,
> > >   				struct file *swap_file, sector_t *span)
> > >   {
> > >   	struct address_space *mapping = swap_file->f_mapping;
> > >   	struct inode *inode = mapping->host;
> > > +	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
> > >   	sector_t cur_lblock;
> > >   	sector_t last_lblock;
> > >   	sector_t pblock;
> > > @@ -3793,6 +3845,7 @@ static int check_swap_activate_fast(struct swap_info_struct *sis,
> > >   	sector_t highest_pblock = 0;
> > >   	int nr_extents = 0;
> > >   	unsigned long nr_pblocks;
> > > +	unsigned int blocks_per_sec = sbi->blocks_per_seg * sbi->segs_per_sec;
> > 
> > Ditto,
> > 
> > >   	u64 len;
> > >   	int ret;
> > > @@ -3827,6 +3880,13 @@ static int check_swap_activate_fast(struct swap_info_struct *sis,
> > >   		pblock = map.m_pblk;
> > >   		nr_pblocks = map.m_len;
> > > +		if ((pblock - SM_I(sbi)->main_blkaddr) & (blocks_per_sec - 1) ||
> > > +			nr_pblocks & (blocks_per_sec - 1)) {
> > > +			pr_err("swapon: swapfile isn't section-aligned\n");
> > 
> > Ditto,
> > 
> > > +			ret = -EINVAL;
> > > +			goto out;
> > > +		}
> > > +
> > >   		if (cur_lblock + nr_pblocks >= sis->max)
> > >   			nr_pblocks = sis->max - cur_lblock;
> > > @@ -3878,6 +3938,9 @@ static int check_swap_activate(struct swap_info_struct *sis,
> > >   	if (PAGE_SIZE == F2FS_BLKSIZE)
> > >   		return check_swap_activate_fast(sis, swap_file, span);
> > > +	if (f2fs_check_file_aligned(inode))
> > 
> > ret = f2fs_check_file_aligned();
> > if (ret)
> > 	return ret;
> > 
> > Thanks,
> > 
> > > +		return -EINVAL;
> > > +
> > >   	blocks_per_page = bytes_to_blks(inode, PAGE_SIZE);
> > >   	/*
> > > 
> > 
> > 
> > _______________________________________________
> > Linux-f2fs-devel mailing list
> > Linux-f2fs-devel@...ts.sourceforge.net
> > https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
> 
> 
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