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;
83 BUG_ON(!IS_ALIGNED(this->size, 512));
86 struct drbd_interval *here =
87 rb_entry(*new, struct drbd_interval, rb);
90 if (this->sector < here->sector)
91 new = &(*new)->rb_left;
92 else if (this->sector > here->sector)
93 new = &(*new)->rb_right;
95 new = &(*new)->rb_left;
97 new = &(*new)->rb_right;
102 rb_link_node(&this->rb, parent, new);
103 rb_insert_augmented(&this->rb, root, &augment_callbacks);
108 * drbd_contains_interval - check if a tree contains a given interval
109 * @sector: start sector of @interval
110 * @interval: may not be a valid pointer
112 * Returns if the tree contains the node @interval with start sector @start.
113 * Does not dereference @interval until @interval is known to be a valid object
114 * in @tree. Returns %false if @interval is in the tree but with a different
118 drbd_contains_interval(struct rb_root *root, sector_t sector,
119 struct drbd_interval *interval)
121 struct rb_node *node = root->rb_node;
124 struct drbd_interval *here =
125 rb_entry(node, struct drbd_interval, rb);
127 if (sector < here->sector)
128 node = node->rb_left;
129 else if (sector > here->sector)
130 node = node->rb_right;
131 else if (interval < here)
132 node = node->rb_left;
133 else if (interval > here)
134 node = node->rb_right;
142 * drbd_remove_interval - remove an interval from a tree
145 drbd_remove_interval(struct rb_root *root, struct drbd_interval *this)
147 rb_erase_augmented(&this->rb, root, &augment_callbacks);
151 * drbd_find_overlap - search for an interval overlapping with [sector, sector + size)
152 * @sector: start sector
153 * @size: size, aligned to 512 bytes
155 * Returns an interval overlapping with [sector, sector + size), or NULL if
156 * there is none. When there is more than one overlapping interval in the
157 * tree, the interval with the lowest start sector is returned, and all other
158 * overlapping intervals will be on the right side of the tree, reachable with
161 struct drbd_interval *
162 drbd_find_overlap(struct rb_root *root, sector_t sector, unsigned int size)
164 struct rb_node *node = root->rb_node;
165 struct drbd_interval *overlap = NULL;
166 sector_t end = sector + (size >> 9);
168 BUG_ON(!IS_ALIGNED(size, 512));
171 struct drbd_interval *here =
172 rb_entry(node, struct drbd_interval, rb);
175 sector < interval_end(node->rb_left)) {
176 /* Overlap if any must be on left side */
177 node = node->rb_left;
178 } else if (here->sector < end &&
179 sector < here->sector + (here->size >> 9)) {
182 } else if (sector >= here->sector) {
183 /* Overlap if any must be on right side */
184 node = node->rb_right;
191 struct drbd_interval *
192 drbd_next_overlap(struct drbd_interval *i, sector_t sector, unsigned int size)
194 sector_t end = sector + (size >> 9);
195 struct rb_node *node;
198 node = rb_next(&i->rb);
201 i = rb_entry(node, struct drbd_interval, rb);
202 if (i->sector >= end)
204 if (sector < i->sector + (i->size >> 9))