2 #include <linux/rbtree_augmented.h>
3 #include "drbd_interval.h"
6 * interval_end - return end of @node
9 sector_t interval_end(struct rb_node *node)
11 struct drbd_interval *this = rb_entry(node, struct drbd_interval, rb);
16 * compute_subtree_last - compute end of @node
18 * The end of an interval is the highest (start + (size >> 9)) value of this
19 * node and of its children. Called for @node and its parents whenever the end
22 static inline sector_t
23 compute_subtree_last(struct drbd_interval *node)
25 sector_t max = node->sector + (node->size >> 9);
27 if (node->rb.rb_left) {
28 sector_t left = interval_end(node->rb.rb_left);
32 if (node->rb.rb_right) {
33 sector_t right = interval_end(node->rb.rb_right);
40 static void augment_propagate(struct rb_node *rb, struct rb_node *stop)
43 struct drbd_interval *node = rb_entry(rb, struct drbd_interval, rb);
44 sector_t subtree_last = compute_subtree_last(node);
45 if (node->end == subtree_last)
47 node->end = subtree_last;
48 rb = rb_parent(&node->rb);
52 static void augment_copy(struct rb_node *rb_old, struct rb_node *rb_new)
54 struct drbd_interval *old = rb_entry(rb_old, struct drbd_interval, rb);
55 struct drbd_interval *new = rb_entry(rb_new, struct drbd_interval, rb);
60 static void augment_rotate(struct rb_node *rb_old, struct rb_node *rb_new)
62 struct drbd_interval *old = rb_entry(rb_old, struct drbd_interval, rb);
63 struct drbd_interval *new = rb_entry(rb_new, struct drbd_interval, rb);
66 old->end = compute_subtree_last(old);
69 static const struct rb_augment_callbacks augment_callbacks = {
76 * drbd_insert_interval - insert a new interval into a tree
79 drbd_insert_interval(struct rb_root *root, struct drbd_interval *this)
81 struct rb_node **new = &root->rb_node, *parent = NULL;
82 sector_t this_end = this->sector + (this->size >> 9);
84 BUG_ON(!IS_ALIGNED(this->size, 512));
87 struct drbd_interval *here =
88 rb_entry(*new, struct drbd_interval, rb);
91 if (here->end < this_end)
93 if (this->sector < here->sector)
94 new = &(*new)->rb_left;
95 else if (this->sector > here->sector)
96 new = &(*new)->rb_right;
98 new = &(*new)->rb_left;
100 new = &(*new)->rb_right;
105 this->end = this_end;
106 rb_link_node(&this->rb, parent, new);
107 rb_insert_augmented(&this->rb, root, &augment_callbacks);
112 * drbd_contains_interval - check if a tree contains a given interval
113 * @sector: start sector of @interval
114 * @interval: may not be a valid pointer
116 * Returns if the tree contains the node @interval with start sector @start.
117 * Does not dereference @interval until @interval is known to be a valid object
118 * in @tree. Returns %false if @interval is in the tree but with a different
122 drbd_contains_interval(struct rb_root *root, sector_t sector,
123 struct drbd_interval *interval)
125 struct rb_node *node = root->rb_node;
128 struct drbd_interval *here =
129 rb_entry(node, struct drbd_interval, rb);
131 if (sector < here->sector)
132 node = node->rb_left;
133 else if (sector > here->sector)
134 node = node->rb_right;
135 else if (interval < here)
136 node = node->rb_left;
137 else if (interval > here)
138 node = node->rb_right;
146 * drbd_remove_interval - remove an interval from a tree
149 drbd_remove_interval(struct rb_root *root, struct drbd_interval *this)
151 rb_erase_augmented(&this->rb, root, &augment_callbacks);
155 * drbd_find_overlap - search for an interval overlapping with [sector, sector + size)
156 * @sector: start sector
157 * @size: size, aligned to 512 bytes
159 * Returns an interval overlapping with [sector, sector + size), or NULL if
160 * there is none. When there is more than one overlapping interval in the
161 * tree, the interval with the lowest start sector is returned, and all other
162 * overlapping intervals will be on the right side of the tree, reachable with
165 struct drbd_interval *
166 drbd_find_overlap(struct rb_root *root, sector_t sector, unsigned int size)
168 struct rb_node *node = root->rb_node;
169 struct drbd_interval *overlap = NULL;
170 sector_t end = sector + (size >> 9);
172 BUG_ON(!IS_ALIGNED(size, 512));
175 struct drbd_interval *here =
176 rb_entry(node, struct drbd_interval, rb);
179 sector < interval_end(node->rb_left)) {
180 /* Overlap if any must be on left side */
181 node = node->rb_left;
182 } else if (here->sector < end &&
183 sector < here->sector + (here->size >> 9)) {
186 } else if (sector >= here->sector) {
187 /* Overlap if any must be on right side */
188 node = node->rb_right;
195 struct drbd_interval *
196 drbd_next_overlap(struct drbd_interval *i, sector_t sector, unsigned int size)
198 sector_t end = sector + (size >> 9);
199 struct rb_node *node;
202 node = rb_next(&i->rb);
205 i = rb_entry(node, struct drbd_interval, rb);
206 if (i->sector >= end)
208 if (sector < i->sector + (i->size >> 9))