Btrfs: remove unnecessary initialization and memory barrior in shrink_delalloc()

Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index fb5c767..5e0e6bc 100644 (file)
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -4034,15 +4034,14 @@ static void shrink_delalloc(struct btrfs_root *root, u64 to_reclaim, u64 orig,
        u64 delalloc_bytes;
        u64 max_reclaim;
        long time_left;
-       unsigned long nr_pages = (2 * 1024 * 1024) >> PAGE_CACHE_SHIFT;
-       int loops = 0;
+       unsigned long nr_pages;
+       int loops;
        enum btrfs_reserve_flush_enum flush;
 
        trans = (struct btrfs_trans_handle *)current->journal_info;
        block_rsv = &root->fs_info->delalloc_block_rsv;
        space_info = block_rsv->space_info;
 
-       smp_mb();
        delalloc_bytes = percpu_counter_sum_positive(
                                                &root->fs_info->delalloc_bytes);
        if (delalloc_bytes == 0) {
@@ -4052,6 +4051,7 @@ static void shrink_delalloc(struct btrfs_root *root, u64 to_reclaim, u64 orig,
                return;
        }
 
+       loops = 0;
        while (delalloc_bytes && loops < 3) {
                max_reclaim = min(delalloc_bytes, to_reclaim);
                nr_pages = max_reclaim >> PAGE_CACHE_SHIFT;
@@ -4082,7 +4082,6 @@ static void shrink_delalloc(struct btrfs_root *root, u64 to_reclaim, u64 orig,
                        if (time_left)
                                break;
                }
-               smp_mb();
                delalloc_bytes = percpu_counter_sum_positive(
                                                &root->fs_info->delalloc_bytes);
        }