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| author | Robin Dong <hao.bigrat@gmail.com> | 2011-07-17 23:27:43 -0400 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2011-07-17 23:27:43 -0400 |
| commit | 015861badd0db43d025bbb538f8fc62dfaf3f18d (patch) | |
| tree | e1e7f6ea3f4cd41ecc030f07a4a454141dd2e158 /fs/ext4 | |
| parent | c6a0371cbefade85376bbc326d18451860632dce (diff) | |
| download | blackbird-op-linux-015861badd0db43d025bbb538f8fc62dfaf3f18d.tar.gz blackbird-op-linux-015861badd0db43d025bbb538f8fc62dfaf3f18d.zip | |
ext4: avoid wasted extent cache lookup if !PUNCH_OUT_EXT
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@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Reviewed-by: Lukas Czerner <lczerner@redhat.com>
Reviewed-by: Eric Gouriou <egouriou@google.com>
Diffstat (limited to 'fs/ext4')
| -rw-r--r-- | 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 3d8c5f50ba33..b8acfab00224 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -3320,8 +3320,8 @@ 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) { /* |
