Chris Mason wrote:
> On Thu, Mar 25, 2010 at 08:30:17PM +0800, Miao Xie wrote:
>> From: Zhao Lei <zhaolei@xxxxxxxxxxxxxx>
>>
>> num_copies's value is not changed in this function,
>> and it is not necessary to calculate its value multi-times.
>
> It is true that we don't need to calculate this multiple times, but with
> the existing code the calculation is only done when there is an IO
> error.
>
> We could use a check for num_copies == 0 before calling the calc
> function.
>
> -chris
Hello, chris
I'll modify this patch to read num_copies only in IO error.
Thanks
Zhaolei
>> Signed-off-by: Zhao Lei <zhaolei@xxxxxxxxxxxxxx>
>> Signed-off-by: Miao Xie <miaox@xxxxxxxxxxxxxx>
>> ---
>> fs/btrfs/disk-io.c | 5 ++---
>> 1 files changed, 2 insertions(+), 3 deletions(-)
>>
>> diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
>> index 11d0ad3..79d9196 100644
>> --- a/fs/btrfs/disk-io.c
>> +++ b/fs/btrfs/disk-io.c
>> @@ -301,7 +301,8 @@ static int btree_read_extent_buffer_pages(struct btrfs_root *root,
>> {
>> struct extent_io_tree *io_tree;
>> int ret;
>> - int num_copies = 0;
>> + int num_copies = btrfs_num_copies(&root->fs_info->mapping_tree,
>> + eb->start, eb->len);
>> int mirror_num = 0;
>>
>> io_tree = &BTRFS_I(root->fs_info->btree_inode)->io_tree;
>> @@ -312,8 +313,6 @@ static int btree_read_extent_buffer_pages(struct btrfs_root *root,
>> !verify_parent_transid(io_tree, eb, parent_transid))
>> return ret;
>>
>> - num_copies = btrfs_num_copies(&root->fs_info->mapping_tree,
>> - eb->start, eb->len);
>> if (num_copies == 1)
>> return ret;
>>
>> --
>> 1.6.5.2
>>
>>
>> --
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