Re: [PATCH v2] f2fs: fix to release inode page in get_new_data_page

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

Hi Jaegeuk,

How about using v3 instead of v2 since it fixes the same type issue
in f2fs_convert_inline_dir?

Thanks,

> -----Original Message-----
> From: Chao Yu [mailto:chao2.yu@samsung.com]
> Sent: Monday, August 03, 2015 9:03 PM
> To: 'Jaegeuk Kim'
> Cc: linux-kernel@vger.kernel.org; linux-f2fs-devel@lists.sourceforge.net
> Subject: Re: [f2fs-dev] [PATCH v2] f2fs: fix to release inode page in get_new_data_page
> 
> >From c0f2abda489150d5d458aaae9026f1243daea604 Mon Sep 17 00:00:00 2001
> From: Chao Yu <chao2.yu@samsung.com>
> Date: Tue, 14 Jul 2015 18:14:06 +0800
> Subject: [PATCH v3] f2fs: fix to release inode page correctly
> 
> In following call path, we will pass a locked and referenced ipage
> pointer to get_new_data_page:
>  - init_inode_metadata
>   - make_empty_dir
>    - get_new_data_page
> 
> There are two exit paths in get_new_data_page when error occurs:
> 1) grab_cache_page fails, ipage will not be released;
> 2) f2fs_reserve_block fails, ipage will be released in callee.
> 
> So, it's not consistent for error handling in get_new_data_page.
> 
> For f2fs_reserve_block, it's not very easy to change the rule
> of error handling, since it's already complicated.
> 
> Here we deside to choose an easy way to fix this issue:
> If any error occur in get_new_data_page, we will ensure releasing
> ipage in this function.
> 
> The same issue is in f2fs_convert_inline_dir, fix that too.
> 
> Signed-off-by: Chao Yu <chao2.yu@samsung.com>
> ---
> v3:
>  * fix the same issue in f2fs_convert_inline_dir.
> 
>  fs/f2fs/data.c   | 11 +++++++++--
>  fs/f2fs/inline.c | 13 ++++++++++---
>  2 files changed, 19 insertions(+), 5 deletions(-)
> 
> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> index e58562e..5da0529 100644
> --- a/fs/f2fs/data.c
> +++ b/fs/f2fs/data.c
> @@ -387,7 +387,8 @@ repeat:
>   *
>   * Also, caller should grab and release a rwsem by calling f2fs_lock_op() and
>   * f2fs_unlock_op().
> - * Note that, ipage is set only by make_empty_dir.
> + * Note that, ipage is set only by make_empty_dir, and if any error occur,
> + * ipage should be released by this function.
>   */
>  struct page *get_new_data_page(struct inode *inode,
>  		struct page *ipage, pgoff_t index, bool new_i_size)
> @@ -398,8 +399,14 @@ struct page *get_new_data_page(struct inode *inode,
>  	int err;
>  repeat:
>  	page = grab_cache_page(mapping, index);
> -	if (!page)
> +	if (!page) {
> +		/*
> +		 * before exiting, we should make sure ipage will be released
> +		 * if any error occur.
> +		 */
> +		f2fs_put_page(ipage, 1);
>  		return ERR_PTR(-ENOMEM);
> +	}
> 
>  	set_new_dnode(&dn, inode, ipage, NULL, 0);
>  	err = f2fs_reserve_block(&dn, index);
> diff --git a/fs/f2fs/inline.c b/fs/f2fs/inline.c
> index a13ffcc..79d18d5 100644
> --- a/fs/f2fs/inline.c
> +++ b/fs/f2fs/inline.c
> @@ -360,6 +360,10 @@ int make_empty_inline_dir(struct inode *inode, struct inode *parent,
>  	return 0;
>  }
> 
> +/*
> + * NOTE: ipage is grabbed by caller, but if any error occurs, we should
> + * release ipage in this function.
> + */
>  static int f2fs_convert_inline_dir(struct inode *dir, struct page *ipage,
>  				struct f2fs_inline_dentry *inline_dentry)
>  {
> @@ -369,8 +373,10 @@ static int f2fs_convert_inline_dir(struct inode *dir, struct page *ipage,
>  	int err;
> 
>  	page = grab_cache_page(dir->i_mapping, 0);
> -	if (!page)
> +	if (!page) {
> +		f2fs_put_page(ipage, 1);
>  		return -ENOMEM;
> +	}
> 
>  	set_new_dnode(&dn, dir, ipage, NULL, 0);
>  	err = f2fs_reserve_block(&dn, 0);
> @@ -434,8 +440,9 @@ int f2fs_add_inline_entry(struct inode *dir, const struct qstr *name,
>  						slots, NR_INLINE_DENTRY);
>  	if (bit_pos >= NR_INLINE_DENTRY) {
>  		err = f2fs_convert_inline_dir(dir, ipage, dentry_blk);
> -		if (!err)
> -			err = -EAGAIN;
> +		if (err)
> +			return err;
> +		err = -EAGAIN;
>  		goto out;
>  	}
> 
> --
> 2.4.2
> 
> 
> 
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