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From: Jan Kara <jack@suse.cz>
To: Chengguang Xu <cgxu519@mykernel.net>
Cc: miklos@szeredi.hu, jack@suse.cz, amir73il@gmail.com,
	linux-unionfs@vger.kernel.org, linux-fsdevel@vger.kernel.org
Subject: Re: [RFC PATCH v3 07/10] ovl: implement overlayfs' ->write_inode operation
Date: Tue, 10 Nov 2020 14:45:51 +0100
Message-ID: <20201110134551.GA28132@quack2.suse.cz> (raw)
In-Reply-To: <20201108140307.1385745-8-cgxu519@mykernel.net>

On Sun 08-11-20 22:03:04, Chengguang Xu wrote:
> +static int ovl_write_inode(struct inode *inode,
> +			   struct writeback_control *wbc)
> +{
> +	struct ovl_fs *ofs = inode->i_sb->s_fs_info;
> +	struct inode *upper = ovl_inode_upper(inode);
> +	unsigned long iflag = 0;
> +	int ret = 0;
> +
> +	if (!upper)
> +		return 0;
> +
> +	if (!ovl_should_sync(ofs))
> +		return 0;
> +
> +	if (upper->i_sb->s_op->write_inode)
> +		ret = upper->i_sb->s_op->write_inode(inode, wbc);
> +
> +	iflag |= upper->i_state & I_DIRTY_ALL;
> +
> +	if (mapping_writably_mapped(upper->i_mapping) ||
> +	    mapping_tagged(upper->i_mapping, PAGECACHE_TAG_WRITEBACK))
> +		iflag |= I_DIRTY_PAGES;
> +
> +	if (iflag)
> +		ovl_mark_inode_dirty(inode);

I think you didn't incorporate feedback we were speaking about in the last
version of the series. May comment in [1] still applies - you can miss
inodes dirtied through mmap when you decide to clean the inode here. So
IMHO you need something like:

	if (inode_is_open_for_write(inode))
		ovl_mark_inode_dirty(inode);

here to keep inode dirty while it is open for write (and not based on upper
inode state which is unreliable).

								Honza

[1] https://lore.kernel.org/linux-fsdevel/20201105140332.GG32718@quack2.suse.cz/

> +
> +	return ret;
> +}
> +
>  static void ovl_evict_inode(struct inode *inode)
>  {
>  	struct ovl_fs *ofs = inode->i_sb->s_fs_info;
> @@ -411,6 +440,7 @@ static const struct super_operations ovl_super_operations = {
>  	.destroy_inode	= ovl_destroy_inode,
>  	.drop_inode	= generic_delete_inode,
>  	.evict_inode	= ovl_evict_inode,
> +	.write_inode	= ovl_write_inode,
>  	.put_super	= ovl_put_super,
>  	.sync_fs	= ovl_sync_fs,
>  	.statfs		= ovl_statfs,
> -- 
> 2.26.2
> 
> 
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR

  reply index

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-08 14:02 [RFC PATCH v3 00/10] implement containerized syncfs for overlayfs Chengguang Xu
2020-11-08 14:02 ` [RFC PATCH v3 01/10] ovl: setup overlayfs' private bdi Chengguang Xu
2020-11-08 14:02 ` [RFC PATCH v3 02/10] ovl: introduce waiting list for syncfs Chengguang Xu
2020-11-08 14:03 ` [RFC PATCH v3 03/10] ovl: implement ->writepages operation Chengguang Xu
2020-11-08 14:03 ` [RFC PATCH v3 04/10] ovl: implement overlayfs' ->evict_inode operation Chengguang Xu
2020-11-08 14:03 ` [RFC PATCH v3 05/10] ovl: mark overlayfs' inode dirty on modification Chengguang Xu
2020-11-08 14:03 ` [RFC PATCH v3 06/10] ovl: mark overlayfs' inode dirty on shared mmap Chengguang Xu
2020-11-11 13:05   ` 回复:[RFC " Chengguang Xu
2020-11-11 15:20     ` [RFC " Amir Goldstein
2020-11-11 16:09       ` Chengguang Xu
2020-11-08 14:03 ` [RFC PATCH v3 07/10] ovl: implement overlayfs' ->write_inode operation Chengguang Xu
2020-11-10 13:45   ` Jan Kara [this message]
2020-11-10 15:12     ` Chengguang Xu
2020-11-11 10:54       ` Jan Kara
2020-11-10 16:18     ` Amir Goldstein
2020-11-08 14:03 ` [RFC PATCH v3 08/10] ovl: cache dirty overlayfs' inode Chengguang Xu
2020-11-08 14:03 ` [RFC PATCH v3 09/10] ovl: introduce helper of syncfs writeback inode waiting Chengguang Xu
2020-11-09  3:33   ` 回复:[RFC " Chengguang Xu
2020-11-09  7:07     ` [RFC " Amir Goldstein
2020-11-09  8:34       ` Chengguang Xu
2020-11-09 10:07         ` Amir Goldstein
2020-11-09 12:06           ` Chengguang Xu
2020-11-08 14:03 ` [RFC PATCH v3 10/10] ovl: implement containerized syncfs for overlayfs Chengguang Xu

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