Re: [PATCH 2/2] ext4: Use EXT_MAX_BLOCKS in ext4_es_can_be_merged()

Zheng Liu
2014-04-23T07:21:08Z

On Tue, Apr 15, 2014 at 08:08:22PM +0200, Lukas Czerner wrote:
> In ext4_es_can_be_merged() when checking whether we can merge two
> extents we should use EXT_MAX_BLOCKS instead of defining it manually.
> Also if it is really the case we should notify userspace because clearly
> there is a bug in extent status tree implementation since this should
> never happen.
>
> Signed-off-by: Lukas Czerner <lczerner@redhat.com>

Thanks for fixing this. It looks good to me.
Reviewed-by: Zheng Liu <wenqing.lz@taobao.com>

- Zheng

> ---
> fs/ext4/extents_status.c | 8 +++++++-
> 1 file changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/fs/ext4/extents_status.c b/fs/ext4/extents_status.c
> index 3c47b4e..b38d71a 100644
> --- a/fs/ext4/extents_status.c
> +++ b/fs/ext4/extents_status.c
> @@ -344,8 +344,14 @@ static int ext4_es_can_be_merged(struct extent_status *es1,
> if (ext4_es_status(es1) != ext4_es_status(es2))
> return 0;
>
> - if (((__u64) es1->es_len) + es2->es_len > 0xFFFFFFFFULL)
> + if (((__u64) es1->es_len) + es2->es_len > EXT_MAX_BLOCKS) {
> + pr_warn("ES assertion failed when merging extents. "
> + "The sum of lengths of es1 (%d) and es2 (%d) "
> + "is bigger than allowed file size (%d)\n",
> + es1->es_len, es2->es_len, EXT_MAX_BLOCKS);
> + WARN_ON(1);
> return 0;
> + }
>
> if (((__u64) es1->es_lblk) + es1->es_len != es2->es_lblk)
> return 0;
> --
> 1.8.3.1
>
> --
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