Re: [PATCH] btrfs: defrag: fix check to see if next extent can be defragged too

[Qu Wenruo <wqu@suse.com>]

在 2026/10/8 01:50, fdmanana@kernel.org 写道:
> From: Filipe Manana <fdmanana@suse.com>
> 
> We want to check if the next extent is at maximum capacity but we are
> passing the current extent map to get_extent_max_capacity() and not
> the next extent map. For example if the current extent is compressed (its
> maximum capacity is 128K) and the next extent is uncompressed (its
> maximum capacity is 128M), then we can bail out and not defrag the next
> extent too - when for example the next extent as a size of 128K, is
> uncompressed, and the extent threshold is >= 256K.
> 
> Fixes: 979b25c300db ("btrfs: defrag: don't defrag extents which are already at max capacity")
> Signed-off-by: Filipe Manana <fdmanana@suse.com>

Reviewed-by: Qu Wenruo <wqu@suse.com>

Thanks,
Qu

> ---
>   fs/btrfs/defrag.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/fs/btrfs/defrag.c b/fs/btrfs/defrag.c
> index 75c87aee5de9..7010d714cfe1 100644
> --- a/fs/btrfs/defrag.c
> +++ b/fs/btrfs/defrag.c
> @@ -811,7 +811,7 @@ static bool defrag_check_next_extent(struct inode *inode, struct extent_map *em,
>   	 * If the next extent is at its max capacity, defragging current extent
>   	 * makes no sense, as the total number of extents won't change.
>   	 */
> -	if (next->len >= get_extent_max_capacity(fs_info, em))
> +	if (next->len >= get_extent_max_capacity(fs_info, next))
>   		goto out;
>   	/* Skip older extent */
>   	if (next->generation < newer_than)