Re: [PATCH 4.4 48/91] ext4: fix inline data error paths

[Ben Hutchings]

On Fri, 2017-03-10 at 10:08 +0100, Greg Kroah-Hartman wrote:
> 4.4-stable review patch.ÂÂIf anyone has any objections, please let me
> know.
> 
> ------------------
> 
> From: Theodore Ts'o <tytso@xxxxxxx>
> 
> commit eb5efbcb762aee4b454b04f7115f73ccbcf8f0ef upstream.
> 
> The write_end() function must always unlock the page and drop its ref
> count, even on an error.

This looks like a theoretical rather than a real issue, because I can't
see how ext4_write_inline_data_end() ever returns an error code.

> Signed-off-by: Theodore Ts'o <tytso@xxxxxxx>
> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> 
> ---
> Âfs/ext4/inline.c |ÂÂÂÂ9 ++++++++-
> Âfs/ext4/inode.cÂÂ|ÂÂÂ20 +++++++++++++++-----
> Â2 files changed, 23 insertions(+), 6 deletions(-)
> 
> --- a/fs/ext4/inline.c
> +++ b/fs/ext4/inline.c
> @@ -933,8 +933,15 @@ int ext4_da_write_inline_data_end(struct
> > Â				ÂÂstruct page *page)
> Â{
> Â	int i_size_changed = 0;
> +	int ret;
> Â
> -	copied = ext4_write_inline_data_end(inode, pos, len, copied, page);
> +	ret = ext4_write_inline_data_end(inode, pos, len, copied, page);
> +	if (ret < 0) {
> +		unlock_page(page);
> +		put_page(page);
[...]

For 4.4 each put_page() should ideally be changed to
page_cache_release().  It makes no practical difference but would be
consistent with other paths.

Ben.

-- 
Ben Hutchings
If you seem to know what you are doing, you'll be given more to do.

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