RE: [f2fs-dev] Space leak in f2fs

[Chao Yu <chao2.yu@samsung.com>]

Hi Jaegeuk,

> -----Original Message-----
> From: Jaegeuk Kim [mailto:jaegeuk@kernel.org]
> Sent: Friday, May 15, 2015 5:14 AM
> To: hujianyang
> Cc: linux-fsdevel@vger.kernel.org; linux-f2fs-devel@lists.sourceforge.net
> Subject: Re: [f2fs-dev] Space leak in f2fs
> 
> Hi Hu,
> 
> I've been rethinking about whole this issue differently.
> And, now I'm starting to test with the below patch instead of previous one.
> 
> Thanks,
> 
> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
> ---
>  fs/f2fs/checkpoint.c | 19 +++++++++++++++++++
>  fs/f2fs/data.c       |  4 ++++
>  fs/f2fs/f2fs.h       |  1 +
>  fs/f2fs/super.c      | 15 ---------------
>  4 files changed, 24 insertions(+), 15 deletions(-)
> 
> diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
> index 7b7a9d8..74875fb 100644
> --- a/fs/f2fs/checkpoint.c
> +++ b/fs/f2fs/checkpoint.c
> @@ -378,6 +378,20 @@ static void __remove_ino_entry(struct f2fs_sb_info *sbi, nid_t ino, int
> type)
>  	spin_unlock(&im->ino_lock);
>  }
> 
> +static bool __exist_ino_entry(struct f2fs_sb_info *sbi, nid_t ino, int type)
> +{
> +	struct inode_management *im = &sbi->im[type];
> +	struct ino_entry *e;
> +	bool exist = false;
> +
> +	spin_lock(&im->ino_lock);
> +	e = radix_tree_lookup(&im->ino_root, ino);
> +	if (e)
> +		exist = true;
> +	spin_unlock(&im->ino_lock);
> +	return exist;
> +}
> +
>  void add_dirty_inode(struct f2fs_sb_info *sbi, nid_t ino, int type)
>  {
>  	/* add new dirty ino entry into list */
> @@ -458,6 +472,11 @@ void remove_orphan_inode(struct f2fs_sb_info *sbi, nid_t ino)
>  	__remove_ino_entry(sbi, ino, ORPHAN_INO);
>  }
> 
> +bool is_orphan_inode(struct f2fs_sb_info *sbi, nid_t ino)
> +{
> +	return __exist_ino_entry(sbi, ino, ORPHAN_INO);
> +}
> +
>  static void recover_orphan_inode(struct f2fs_sb_info *sbi, nid_t ino)
>  {
>  	struct inode *inode = f2fs_iget(sbi->sb, ino);
> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> index b0cc2aa..1988f5f 100644
> --- a/fs/f2fs/data.c
> +++ b/fs/f2fs/data.c
> @@ -1749,6 +1749,10 @@ write:
>  		goto out;
>  	}
> 
> +	/* if orphan inode, we don't need to write its data */
> +	if (is_orphan_inode(sbi, inode->i_ino))
> +		goto out;

When user create a temp file by invoking open with O_TMPFILE flag,
in ->tmpfile our temp file will be added into orphan list as its
nlink is zero.

If we skip writting out data for this orphan inode, later, even though
we add nlink/directory entry for orphan inode by calling linkat,
our file will contain inconsistent data between in-memory and on-disk.

So how about considering for this case?

BTW, the previous fixing patch looks good to me.

Thanks,

> +
>  	if (!wbc->for_reclaim)
>  		need_balance_fs = true;
>  	else if (has_not_enough_free_secs(sbi, 0))
> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> index 8f1f21a..697346a 100644
> --- a/fs/f2fs/f2fs.h
> +++ b/fs/f2fs/f2fs.h
> @@ -1726,6 +1726,7 @@ int acquire_orphan_inode(struct f2fs_sb_info *);
>  void release_orphan_inode(struct f2fs_sb_info *);
>  void add_orphan_inode(struct f2fs_sb_info *, nid_t);
>  void remove_orphan_inode(struct f2fs_sb_info *, nid_t);
> +bool is_orphan_inode(struct f2fs_sb_info *, nid_t);
>  void recover_orphan_inodes(struct f2fs_sb_info *);
>  int get_valid_checkpoint(struct f2fs_sb_info *);
>  void update_dirty_page(struct inode *, struct page *);
> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
> index 19438f2..1d0973a 100644
> --- a/fs/f2fs/super.c
> +++ b/fs/f2fs/super.c
> @@ -422,20 +422,6 @@ static struct inode *f2fs_alloc_inode(struct super_block *sb)
>  	return &fi->vfs_inode;
>  }
> 
> -static int f2fs_drop_inode(struct inode *inode)
> -{
> -	/*
> -	 * This is to avoid a deadlock condition like below.
> -	 * writeback_single_inode(inode)
> -	 *  - f2fs_write_data_page
> -	 *    - f2fs_gc -> iput -> evict
> -	 *       - inode_wait_for_writeback(inode)
> -	 */
> -	if (!inode_unhashed(inode) && inode->i_state & I_SYNC)
> -		return 0;
> -	return generic_drop_inode(inode);
> -}
> -
>  /*
>   * f2fs_dirty_inode() is called from __mark_inode_dirty()
>   *
> @@ -759,7 +745,6 @@ restore_opts:
> 
>  static struct super_operations f2fs_sops = {
>  	.alloc_inode	= f2fs_alloc_inode,
> -	.drop_inode	= f2fs_drop_inode,
>  	.destroy_inode	= f2fs_destroy_inode,
>  	.write_inode	= f2fs_write_inode,
>  	.dirty_inode	= f2fs_dirty_inode,
> --
> 2.1.1
> 
> 
> 
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