#include "scrub/scrub.h"
#include "scrub/bitmap.h"
-/* Iterate each interval of a bitmap. Do not change the bitmap. */
-#define for_each_xbitmap_extent(bex, bitmap) \
- list_for_each_entry((bex), &(bitmap)->list, list)
+#include <linux/interval_tree_generic.h>
+
+struct xbitmap_node {
+ struct rb_node bn_rbnode;
+
+ /* First set bit of this interval and subtree. */
+ uint64_t bn_start;
+
+ /* Last set bit of this interval. */
+ uint64_t bn_last;
+
+ /* Last set bit of this subtree. Do not touch this. */
+ uint64_t __bn_subtree_last;
+};
+
+/* Define our own interval tree type with uint64_t parameters. */
+
+#define START(node) ((node)->bn_start)
+#define LAST(node) ((node)->bn_last)
/*
- * Set a range of this bitmap. Caller must ensure the range is not set.
- *
- * This is the logical equivalent of bitmap |= mask(start, len).
+ * These functions are defined by the INTERVAL_TREE_DEFINE macro, but we'll
+ * forward-declare them anyway for clarity.
*/
+static inline void
+xbitmap_tree_insert(struct xbitmap_node *node, struct rb_root_cached *root);
+
+static inline void
+xbitmap_tree_remove(struct xbitmap_node *node, struct rb_root_cached *root);
+
+static inline struct xbitmap_node *
+xbitmap_tree_iter_first(struct rb_root_cached *root, uint64_t start,
+ uint64_t last);
+
+static inline struct xbitmap_node *
+xbitmap_tree_iter_next(struct xbitmap_node *node, uint64_t start,
+ uint64_t last);
+
+INTERVAL_TREE_DEFINE(struct xbitmap_node, bn_rbnode, uint64_t,
+ __bn_subtree_last, START, LAST, static inline, xbitmap_tree)
+
+/* Iterate each interval of a bitmap. Do not change the bitmap. */
+#define for_each_xbitmap_extent(bn, bitmap) \
+ for ((bn) = rb_entry_safe(rb_first(&(bitmap)->xb_root.rb_root), \
+ struct xbitmap_node, bn_rbnode); \
+ (bn) != NULL; \
+ (bn) = rb_entry_safe(rb_next(&(bn)->bn_rbnode), \
+ struct xbitmap_node, bn_rbnode))
+
+/* Clear a range of this bitmap. */
+int
+xbitmap_clear(
+ struct xbitmap *bitmap,
+ uint64_t start,
+ uint64_t len)
+{
+ struct xbitmap_node *bn;
+ struct xbitmap_node *new_bn;
+ uint64_t last = start + len - 1;
+
+ while ((bn = xbitmap_tree_iter_first(&bitmap->xb_root, start, last))) {
+ if (bn->bn_start < start && bn->bn_last > last) {
+ uint64_t old_last = bn->bn_last;
+
+ /* overlaps with the entire clearing range */
+ xbitmap_tree_remove(bn, &bitmap->xb_root);
+ bn->bn_last = start - 1;
+ xbitmap_tree_insert(bn, &bitmap->xb_root);
+
+ /* add an extent */
+ new_bn = kmalloc(sizeof(struct xbitmap_node),
+ XCHK_GFP_FLAGS);
+ if (!new_bn)
+ return -ENOMEM;
+ new_bn->bn_start = last + 1;
+ new_bn->bn_last = old_last;
+ xbitmap_tree_insert(new_bn, &bitmap->xb_root);
+ } else if (bn->bn_start < start) {
+ /* overlaps with the left side of the clearing range */
+ xbitmap_tree_remove(bn, &bitmap->xb_root);
+ bn->bn_last = start - 1;
+ xbitmap_tree_insert(bn, &bitmap->xb_root);
+ } else if (bn->bn_last > last) {
+ /* overlaps with the right side of the clearing range */
+ xbitmap_tree_remove(bn, &bitmap->xb_root);
+ bn->bn_start = last + 1;
+ xbitmap_tree_insert(bn, &bitmap->xb_root);
+ break;
+ } else {
+ /* in the middle of the clearing range */
+ xbitmap_tree_remove(bn, &bitmap->xb_root);
+ kfree(bn);
+ }
+ }
+
+ return 0;
+}
+
+/* Set a range of this bitmap. */
int
xbitmap_set(
struct xbitmap *bitmap,
uint64_t start,
uint64_t len)
{
- struct xbitmap_range *bmr;
+ struct xbitmap_node *left;
+ struct xbitmap_node *right;
+ uint64_t last = start + len - 1;
+ int error;
- bmr = kmalloc(sizeof(struct xbitmap_range), XCHK_GFP_FLAGS);
- if (!bmr)
- return -ENOMEM;
+ /* Is this whole range already set? */
+ left = xbitmap_tree_iter_first(&bitmap->xb_root, start, last);
+ if (left && left->bn_start <= start && left->bn_last >= last)
+ return 0;
- INIT_LIST_HEAD(&bmr->list);
- bmr->start = start;
- bmr->len = len;
- list_add_tail(&bmr->list, &bitmap->list);
+ /* Clear out everything in the range we want to set. */
+ error = xbitmap_clear(bitmap, start, len);
+ if (error)
+ return error;
+
+ /* Do we have a left-adjacent extent? */
+ left = xbitmap_tree_iter_first(&bitmap->xb_root, start - 1, start - 1);
+ ASSERT(!left || left->bn_last + 1 == start);
+
+ /* Do we have a right-adjacent extent? */
+ right = xbitmap_tree_iter_first(&bitmap->xb_root, last + 1, last + 1);
+ ASSERT(!right || right->bn_start == last + 1);
+
+ if (left && right) {
+ /* combine left and right adjacent extent */
+ xbitmap_tree_remove(left, &bitmap->xb_root);
+ xbitmap_tree_remove(right, &bitmap->xb_root);
+ left->bn_last = right->bn_last;
+ xbitmap_tree_insert(left, &bitmap->xb_root);
+ kfree(right);
+ } else if (left) {
+ /* combine with left extent */
+ xbitmap_tree_remove(left, &bitmap->xb_root);
+ left->bn_last = last;
+ xbitmap_tree_insert(left, &bitmap->xb_root);
+ } else if (right) {
+ /* combine with right extent */
+ xbitmap_tree_remove(right, &bitmap->xb_root);
+ right->bn_start = start;
+ xbitmap_tree_insert(right, &bitmap->xb_root);
+ } else {
+ /* add an extent */
+ left = kmalloc(sizeof(struct xbitmap_node), XCHK_GFP_FLAGS);
+ if (!left)
+ return -ENOMEM;
+ left->bn_start = start;
+ left->bn_last = last;
+ xbitmap_tree_insert(left, &bitmap->xb_root);
+ }
return 0;
}
xbitmap_destroy(
struct xbitmap *bitmap)
{
- struct xbitmap_range *bmr, *n;
+ struct xbitmap_node *bn;
- list_for_each_entry_safe(bmr, n, &bitmap->list, list) {
- list_del(&bmr->list);
- kfree(bmr);
+ while ((bn = xbitmap_tree_iter_first(&bitmap->xb_root, 0, -1ULL))) {
+ xbitmap_tree_remove(bn, &bitmap->xb_root);
+ kfree(bn);
}
}
xbitmap_init(
struct xbitmap *bitmap)
{
- INIT_LIST_HEAD(&bitmap->list);
-}
-
-/* Compare two btree extents. */
-static int
-xbitmap_range_cmp(
- void *priv,
- const struct list_head *a,
- const struct list_head *b)
-{
- struct xbitmap_range *ap;
- struct xbitmap_range *bp;
-
- ap = container_of(a, struct xbitmap_range, list);
- bp = container_of(b, struct xbitmap_range, list);
-
- if (ap->start > bp->start)
- return 1;
- if (ap->start < bp->start)
- return -1;
- return 0;
+ bitmap->xb_root = RB_ROOT_CACHED;
}
/*
*
* This is the logical equivalent of bitmap &= ~sub.
*/
-#define LEFT_ALIGNED (1 << 0)
-#define RIGHT_ALIGNED (1 << 1)
int
xbitmap_disunion(
struct xbitmap *bitmap,
struct xbitmap *sub)
{
- struct list_head *lp;
- struct xbitmap_range *br;
- struct xbitmap_range *new_br;
- struct xbitmap_range *sub_br;
- uint64_t sub_start;
- uint64_t sub_len;
- int state;
- int error = 0;
+ struct xbitmap_node *bn;
+ int error;
- if (list_empty(&bitmap->list) || list_empty(&sub->list))
+ if (xbitmap_empty(bitmap) || xbitmap_empty(sub))
return 0;
- ASSERT(!list_empty(&sub->list));
-
- list_sort(NULL, &bitmap->list, xbitmap_range_cmp);
- list_sort(NULL, &sub->list, xbitmap_range_cmp);
-
- /*
- * Now that we've sorted both lists, we iterate bitmap once, rolling
- * forward through sub and/or bitmap as necessary until we find an
- * overlap or reach the end of either list. We do not reset lp to the
- * head of bitmap nor do we reset sub_br to the head of sub. The
- * list traversal is similar to merge sort, but we're deleting
- * instead. In this manner we avoid O(n^2) operations.
- */
- sub_br = list_first_entry(&sub->list, struct xbitmap_range,
- list);
- lp = bitmap->list.next;
- while (lp != &bitmap->list) {
- br = list_entry(lp, struct xbitmap_range, list);
-
- /*
- * Advance sub_br and/or br until we find a pair that
- * intersect or we run out of extents.
- */
- while (sub_br->start + sub_br->len <= br->start) {
- if (list_is_last(&sub_br->list, &sub->list))
- goto out;
- sub_br = list_next_entry(sub_br, list);
- }
- if (sub_br->start >= br->start + br->len) {
- lp = lp->next;
- continue;
- }
- /* trim sub_br to fit the extent we have */
- sub_start = sub_br->start;
- sub_len = sub_br->len;
- if (sub_br->start < br->start) {
- sub_len -= br->start - sub_br->start;
- sub_start = br->start;
- }
- if (sub_len > br->len)
- sub_len = br->len;
-
- state = 0;
- if (sub_start == br->start)
- state |= LEFT_ALIGNED;
- if (sub_start + sub_len == br->start + br->len)
- state |= RIGHT_ALIGNED;
- switch (state) {
- case LEFT_ALIGNED:
- /* Coincides with only the left. */
- br->start += sub_len;
- br->len -= sub_len;
- break;
- case RIGHT_ALIGNED:
- /* Coincides with only the right. */
- br->len -= sub_len;
- lp = lp->next;
- break;
- case LEFT_ALIGNED | RIGHT_ALIGNED:
- /* Total overlap, just delete ex. */
- lp = lp->next;
- list_del(&br->list);
- kfree(br);
- break;
- case 0:
- /*
- * Deleting from the middle: add the new right extent
- * and then shrink the left extent.
- */
- new_br = kmalloc(sizeof(struct xbitmap_range),
- XCHK_GFP_FLAGS);
- if (!new_br) {
- error = -ENOMEM;
- goto out;
- }
- INIT_LIST_HEAD(&new_br->list);
- new_br->start = sub_start + sub_len;
- new_br->len = br->start + br->len - new_br->start;
- list_add(&new_br->list, &br->list);
- br->len = sub_start - br->start;
- lp = lp->next;
- break;
- default:
- ASSERT(0);
- break;
- }
+ for_each_xbitmap_extent(bn, sub) {
+ error = xbitmap_clear(bitmap, bn->bn_start,
+ bn->bn_last - bn->bn_start + 1);
+ if (error)
+ return error;
}
-out:
- return error;
+ return 0;
}
-#undef LEFT_ALIGNED
-#undef RIGHT_ALIGNED
/*
* Record all btree blocks seen while iterating all records of a btree.
xbitmap_hweight(
struct xbitmap *bitmap)
{
- struct xbitmap_range *bmr;
+ struct xbitmap_node *bn;
uint64_t ret = 0;
- for_each_xbitmap_extent(bmr, bitmap)
- ret += bmr->len;
+ for_each_xbitmap_extent(bn, bitmap)
+ ret += bn->bn_last - bn->bn_start + 1;
return ret;
}
int
xbitmap_walk(
struct xbitmap *bitmap,
- xbitmap_walk_fn fn,
+ xbitmap_walk_fn fn,
void *priv)
{
- struct xbitmap_range *bex;
+ struct xbitmap_node *bn;
int error = 0;
- for_each_xbitmap_extent(bex, bitmap) {
- error = fn(bex->start, bex->len, priv);
+ for_each_xbitmap_extent(bn, bitmap) {
+ error = fn(bn->bn_start, bn->bn_last - bn->bn_start + 1, priv);
if (error)
break;
}
return xbitmap_walk(bitmap, xbitmap_walk_bits_in_run, &wb);
}
+
+/* Does this bitmap have no bits set at all? */
+bool
+xbitmap_empty(
+ struct xbitmap *bitmap)
+{
+ return bitmap->xb_root.rb_root.rb_node == NULL;
+}
projects / users / jedix / linux-maple.git / commitdiff