drbd: compute the end before rb_insert_augmented()

Commit 98683650 "Merge branch 'drbd-8.4_ed6' into
for-3.8-drivers-drbd-8.4_ed6" switches to the new augment API, but the
new API requires that the tree is augmented before rb_insert_augmented()
is called, which is missing.

So we add the augment-code to drbd_insert_interval() when it travels the
tree up to down before rb_insert_augmented().  See the example in
include/linux/interval_tree_generic.h or Documentation/rbtree.txt.

drbd_insert_interval() may cancel the insertion when traveling, in this
case, the just added augment-code does nothing before cancel since the
@this node is already in the subtrees in this case.

CC: Michel Lespinasse <walken@google.com>
CC: stable@kernel.org # v3.10+
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Andreas Gruenbacher <agruen@linbit.com>
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

diff --git a/drivers/block/drbd/drbd_interval.c b/drivers/block/drbd/drbd_interval.c
index 89c497c630b4ee60839571aabf59c9ad553fb229..04a14e0f887830440b307be70075b38655b4a245 100644 (file)
--- a/drivers/block/drbd/drbd_interval.c
+++ b/drivers/block/drbd/drbd_interval.c
@@ -79,6 +79,7 @@ bool
 drbd_insert_interval(struct rb_root *root, struct drbd_interval *this)
 {
        struct rb_node **new = &root->rb_node, *parent = NULL;
+       sector_t this_end = this->sector + (this->size >> 9);
 
        BUG_ON(!IS_ALIGNED(this->size, 512));
 
@@ -87,6 +88,8 @@ drbd_insert_interval(struct rb_root *root, struct drbd_interval *this)
                        rb_entry(*new, struct drbd_interval, rb);
 
                parent = *new;
+               if (here->end < this_end)
+                       here->end = this_end;
                if (this->sector < here->sector)
                        new = &(*new)->rb_left;
                else if (this->sector > here->sector)
@@ -99,6 +102,7 @@ drbd_insert_interval(struct rb_root *root, struct drbd_interval *this)
                        return false;
        }
 
+       this->end = this_end;
        rb_link_node(&this->rb, parent, new);
        rb_insert_augmented(&this->rb, root, &augment_callbacks);
        return true;