On 05/08/2010 12:23 AM, Jan Kara wrote:
When rsv is the right hand side of goal, we should return NULL, because now rsv's prev is NULL, or we return rsv. Signed-off-by: Peter Pan(潘卫平)<wppan@xxxxxxxxxxxxxxxxx> --- fs/ext2/balloc.c | 6 +----- fs/ext3/balloc.c | 6 +----- 2 files changed, 2 insertions(+), 10 deletions(-) diff --git a/fs/ext2/balloc.c b/fs/ext2/balloc.c index 3cf038c..023990f 100644 --- a/fs/ext2/balloc.c +++ b/fs/ext2/balloc.c @@ -323,11 +323,7 @@ search_reserve_window(struct rb_root *root, ext2_fsblk_t goal) * side of the interval containing the goal. If it's the RHS, * we need to back up one. */ - if (rsv->rsv_start> goal) { - n = rb_prev(&rsv->rsv_node); - rsv = rb_entry(n, struct ext2_reserve_window_node, rsv_node); - } - return rsv; + return (rsv->rsv_start< goal) ? rsv : NULL;Hmm, I'm not sure I understand your reasoning. Suppose we have an RB-tree with two intervals 0-10, 20-30. Interval 0-10 is in the root. Now we search for goal 15. In the root we go to right because 10<15, in the next node we go to left because 15< 20. Then the loop terminates. Now your code would return NULL but previous code would return rb_prev of interval 20-30 which is 0-10. And that is what we want as far as I understand what we expect from the function... Honza
You got the point! Many thanks. Regards -- Peter Pan Red Flag Software Co.,Ltd -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
