linux-ext4 - Re: [PATCH] ext4: avoid redundant cache finding if flags not cantian PUNCH

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Date:	Mon, 27 Jun 2011 12:15:00 +0200 (CEST)
From:	Lukas Czerner <lczerner@...hat.com>
To:	Robin Dong <hao.bigrat@...il.com>
cc:	linux-ext4@...r.kernel.org, Robin Dong <sanbai@...bao.com>
Subject: Re: [PATCH] ext4: avoid redundant cache finding if flags not cantian
 PUNCH_OUT

On Mon, 27 Jun 2011, Robin Dong wrote:

> In old code, ext4 will find extent in cache first even flags does
> not contian PUNCH_OUT, that may waste some time.
> 
> Signed-off-by: Robin Dong <sanbai@...bao.com>
> ---
>  fs/ext4/extents.c |    4 ++--
>  1 files changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
> index eb63c7b..d583ec3 100644
> --- a/fs/ext4/extents.c
> +++ b/fs/ext4/extents.c
> @@ -3358,8 +3358,8 @@ int ext4_ext_map_blocks(handle_t *handle, struct inode *inode,
>  	trace_ext4_ext_map_blocks_enter(inode, map->m_lblk, map->m_len, flags);
>  
>  	/* check in cache */
> -	if (ext4_ext_in_cache(inode, map->m_lblk, &newex) &&
> -		((flags & EXT4_GET_BLOCKS_PUNCH_OUT_EXT) == 0)) {
> +	if (((flags & EXT4_GET_BLOCKS_PUNCH_OUT_EXT) == 0) &&
> +		ext4_ext_in_cache(inode, map->m_lblk, &newex)) {

Hi Robin,

The patch is good thanks, but I think that this:

	if (!(flags & EXT4_GET_BLOCKS_PUNCH_OUT_EXT) &&
	    ext4_ext_in_cache(inode, map->m_lblk, &newex)) {

looks better.

Thanks!
-Lukas

>  		if (!newex.ee_start_lo && !newex.ee_start_hi) {
>  			if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
>  				/*
> 
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