[PATCH 02/10] btrfs: reada: Move is_need_to_readahead contition earlier

[Zhao Lei]

Move is_need_to_readahead contition earlier to avoid useless loop
to get relative data for readahead.

Signed-off-by: Zhao Lei <zhao...@cn.fujitsu.com>
---
 fs/btrfs/reada.c | 20 +++++++++-----------
 1 file changed, 9 insertions(+), 11 deletions(-)

diff --git a/fs/btrfs/reada.c b/fs/btrfs/reada.c
index fb21bf0..dcc5b69 100644
--- a/fs/btrfs/reada.c
+++ b/fs/btrfs/reada.c
@@ -665,7 +665,6 @@ static int reada_start_machine_dev(struct btrfs_fs_info 
*fs_info,
        u64 logical;
        int ret;
        int i;
-       int need_kick = 0;
 
        spin_lock(&fs_info->reada_lock);
        if (dev->reada_curr_zone == NULL) {
@@ -701,6 +700,15 @@ static int reada_start_machine_dev(struct btrfs_fs_info 
*fs_info,
 
        spin_unlock(&fs_info->reada_lock);
 
+       spin_lock(&re->lock);
+               if (re->scheduled_for || list_empty(&re->extctl)) {
+                       spin_unlock(&re->lock);
+                       reada_extent_put(fs_info, re);
+                       return 0;
+               }
+               re->scheduled_for = dev;
+       spin_unlock(&re->lock);
+
        /*
         * find mirror num
         */
@@ -712,18 +720,8 @@ static int reada_start_machine_dev(struct btrfs_fs_info 
*fs_info,
        }
        logical = re->logical;
 
-       spin_lock(&re->lock);
-       if (!re->scheduled_for && !list_empty(&re->extctl)) {
-               re->scheduled_for = dev;
-               need_kick = 1;
-       }
-       spin_unlock(&re->lock);
-
        reada_extent_put(fs_info, re);
 
-       if (!need_kick)
-               return 0;
-
        atomic_inc(&dev->reada_in_flight);
        ret = reada_tree_block_flagged(fs_info->extent_root, logical,
                        mirror_num, &eb);
-- 
1.8.5.1



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