2011/6/29 Robin Dong <hao.bigrat@xxxxxxxxx>:
> This patch avoids an extraneous lookup of the extent cache
> in ext4_ext_map_blocks() when the flag
> EXT4_GET_BLOCKS_PUNCH_OUT_EXT is absent.
>
> The existing logic was performing the lookup but not making
> use of the result. The patch simply reverses the order of evaluation
> in the condition.
>
> Since ext4_ext_in_cache() does not initialize newex on misses, bypassing
> its invocation does not introduce any new issue in this regard.
>
> Signed-off-by: Robin Dong <sanbai@xxxxxxxxxx>
> Reviewed-by: Lukas Czerner <lczerner@xxxxxxxxxx>
> Reviewed-by: Eric Gouriou <egouriou@xxxxxxxxxx>
> ---
> 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..fed2633 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) &&
> + ext4_ext_in_cache(inode, map->m_lblk, &newex)) {
> if (!newex.ee_start_lo && !newex.ee_start_hi) {
> if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
Ronbin Dong,
why donnot do this line?
if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
TO
if (!(flags & EXT4_GET_BLOCKS_CREATE) ) {
?
Acked-by: LiuQi <lingjiujianke@xxxxxxxxx>
> /*
> --
> 1.7.1
>
> --
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