From: Zhao Lei <[email protected]> This patch include following modify: 1: It isn't necessary to use following type of goto statement: if (cow) { if (!should_cow_block(trans, root, b)) goto cow_done; ... } cow_done: ... 2: Updating of p->nodes[level] is only necessary on cow. we move these code into if (cow) {} block. 3: Updating of level and p->locks[level] is only necessary when level is changed, so we avoid no-use operation in old code. 4: Add a unlikely() for rare case.
Signed-off-by: Zhao Lei <[email protected]> Signed-off-by: Miao Xie <[email protected]> --- fs/btrfs/ctree.c | 34 ++++++++++++++++------------------ 1 files changed, 16 insertions(+), 18 deletions(-) diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c index c4bc570..4f258ba 100644 --- a/fs/btrfs/ctree.c +++ b/fs/btrfs/ctree.c @@ -1724,15 +1724,12 @@ again: if (!p->skip_locking) p->locks[level] = 1; - if (cow) { - /* - * if we don't really need to cow this block - * then we don't want to set the path blocking, - * so we test it here - */ - if (!should_cow_block(trans, root, b)) - goto cow_done; - + /* + * if we don't really need to cow this block + * then we don't want to set the path blocking, + * so we test it here + */ + if (cow && should_cow_block(trans, root, b)) { btrfs_set_path_blocking(p); err = btrfs_cow_block(trans, root, b, @@ -1743,17 +1740,18 @@ again: ret = err; goto done; } - } -cow_done: - BUG_ON(!cow && ins_len); - if (level != btrfs_header_level(b)) - WARN_ON(1); - level = btrfs_header_level(b); - p->nodes[level] = b; - if (!p->skip_locking) - p->locks[level] = 1; + if (unlikely(level != btrfs_header_level(b))) { + WARN_ON(1); + level = btrfs_header_level(b); + if (!p->skip_locking) + p->locks[level] = 1; + } + p->nodes[level] = b; + } + + BUG_ON(!cow && ins_len); btrfs_clear_path_blocking(p, NULL); /* -- 1.6.5.2 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
