linux-kernel - Re: [PATCH] btrfs: remove unused condition check in btrfs_page

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Message-ID: <20191203082426.GC829117@vader>
Date:   Tue, 3 Dec 2019 00:24:26 -0800
From:   Omar Sandoval <osandov@...ndov.com>
To:     Yunfeng Ye <yeyunfeng@...wei.com>
Cc:     clm@...com, josef@...icpanda.com, dsterba@...e.com,
        linux-btrfs@...r.kernel.org, linux-kernel@...r.kernel.org,
        "hushiyuan@...wei.com" <hushiyuan@...wei.com>,
        "linfeilong@...wei.com" <linfeilong@...wei.com>
Subject: Re: [PATCH] btrfs: remove unused condition check in
 btrfs_page_mkwrite()

On Tue, Dec 03, 2019 at 04:16:43PM +0800, Yunfeng Ye wrote:
> The condition '!ret2' is always true. so remove the unused condition
> check.
> 
> Signed-off-by: Yunfeng Ye <yeyunfeng@...wei.com>

For this sort of change, one should mention how the code got in this
state. In this case, commit 717beb96d969 ("Btrfs: fix regression in
btrfs_page_mkwrite() from vm_fault_t conversion") left behind the check
after moving this code out of the goto.

Ohter than that,

Reviewed-by: Omar Sandoval <osandov@...com>

> ---
>  fs/btrfs/inode.c | 11 ++++-------
>  1 file changed, 4 insertions(+), 7 deletions(-)
> 
> diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
> index 56032c518b26..eef2432597e2 100644
> --- a/fs/btrfs/inode.c
> +++ b/fs/btrfs/inode.c
> @@ -9073,7 +9073,6 @@ vm_fault_t btrfs_page_mkwrite(struct vm_fault *vmf)
>  		ret = VM_FAULT_SIGBUS;
>  		goto out_unlock;
>  	}
> -	ret2 = 0;
> 
>  	/* page is wholly or partially inside EOF */
>  	if (page_start + PAGE_SIZE > size)
> @@ -9097,12 +9096,10 @@ vm_fault_t btrfs_page_mkwrite(struct vm_fault *vmf)
> 
>  	unlock_extent_cached(io_tree, page_start, page_end, &cached_state);
> 
> -	if (!ret2) {
> -		btrfs_delalloc_release_extents(BTRFS_I(inode), PAGE_SIZE);
> -		sb_end_pagefault(inode->i_sb);
> -		extent_changeset_free(data_reserved);
> -		return VM_FAULT_LOCKED;
> -	}
> +	btrfs_delalloc_release_extents(BTRFS_I(inode), PAGE_SIZE);
> +	sb_end_pagefault(inode->i_sb);
> +	extent_changeset_free(data_reserved);
> +	return VM_FAULT_LOCKED;
> 
>  out_unlock:
>  	unlock_page(page);
> -- 
> 2.7.4
>