+/* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
+ * vim:expandtab:shiftwidth=8:tabstop=8:
+ *
+ * Interval tree library used by ldlm extent lock code
+ *
+ * Copyright (c) 2007 Cluster File Systems, Inc.
+ * Author: Huang Wei <huangwei@clusterfs.com>
+ * Author: Jay Xiong <jinshan.xiong@sun.com>
+ *
+ * This file is part of the Lustre file system, http://www.lustre.org
+ * Lustre is a trademark of Cluster File Systems, Inc.
+ *
+ * You may have signed or agreed to another license before downloading
+ * this software. If so, you are bound by the terms and conditions
+ * of that agreement, and the following does not apply to you. See the
+ * LICENSE file included with this distribution for more information.
+ *
+ * If you did not agree to a different license, then this copy of Lustre
+ * is open source software; you can redistribute it and/or modify it
+ * under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * In either case, Lustre is distributed in the hope that it will be
+ * useful, but WITHOUT ANY WARRANTY; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * license text for more details.
+ */
+#ifdef __KERNEL__
+# include <lustre_dlm.h>
+#else
+# include <liblustre.h>
+# include <libcfs/kp30.h>
+#endif
+#include <obd_support.h>
+#include <interval_tree.h>
+
+enum {
+ INTERVAL_RED = 0,
+ INTERVAL_BLACK = 1
+};
+
+static inline int node_is_left_child(struct interval_node *node)
+{
+ LASSERT(node->in_parent != NULL);
+ return node == node->in_parent->in_left;
+}
+
+static inline int node_is_right_child(struct interval_node *node)
+{
+ LASSERT(node->in_parent != NULL);
+ return node == node->in_parent->in_right;
+}
+
+static inline int node_is_red(struct interval_node *node)
+{
+ return node->in_color == INTERVAL_RED;
+}
+
+static inline int node_is_black(struct interval_node *node)
+{
+ return node->in_color == INTERVAL_BLACK;
+}
+
+static inline int extent_compare(struct interval_node_extent *e1,
+ struct interval_node_extent *e2)
+{
+ int rc;
+ if (e1->start == e2->start) {
+ if (e1->end < e2->end)
+ rc = -1;
+ else if (e1->end > e2->end)
+ rc = 1;
+ else
+ rc = 0;
+ } else {
+ if (e1->start < e2->start)
+ rc = -1;
+ else
+ rc = 1;
+ }
+ return rc;
+}
+
+static inline int extent_equal(struct interval_node_extent *e1,
+ struct interval_node_extent *e2)
+{
+ return (e1->start == e2->start) && (e1->end == e2->end);
+}
+
+static inline int extent_overlapped(struct interval_node_extent *e1,
+ struct interval_node_extent *e2)
+{
+ return (e1->start <= e2->end) && (e2->start <= e1->end);
+}
+
+static inline int node_compare(struct interval_node *n1,
+ struct interval_node *n2)
+{
+ return extent_compare(&n1->in_extent, &n2->in_extent);
+}
+
+static inline int node_equal(struct interval_node *n1,
+ struct interval_node *n2)
+{
+ return extent_equal(&n1->in_extent, &n2->in_extent);
+}
+
+static inline __u64 max_u64(__u64 x, __u64 y)
+{
+ return x > y ? x : y;
+}
+
+static inline __u64 min_u64(__u64 x, __u64 y)
+{
+ return x < y ? x : y;
+}
+
+#define interval_for_each(node, root) \
+for (node = interval_first(root); node != NULL; \
+ node = interval_next(node))
+
+#define interval_for_each_reverse(node, root) \
+for (node = interval_last(root); node != NULL; \
+ node = interval_prev(node))
+
+static struct interval_node *interval_first(struct interval_node *node)
+{
+ ENTRY;
+
+ if (!node)
+ RETURN(NULL);
+ while (node->in_left)
+ node = node->in_left;
+ RETURN(node);
+}
+
+static struct interval_node *interval_last(struct interval_node *node)
+{
+ ENTRY;
+
+ if (!node)
+ RETURN(NULL);
+ while (node->in_right)
+ node = node->in_right;
+ RETURN(node);
+}
+
+static struct interval_node *interval_next(struct interval_node *node)
+{
+ ENTRY;
+
+ if (!node)
+ RETURN(NULL);
+ if (node->in_right)
+ RETURN(interval_first(node->in_right));
+ while (node->in_parent && node_is_right_child(node))
+ node = node->in_parent;
+ RETURN(node->in_parent);
+}
+
+static struct interval_node *interval_prev(struct interval_node *node)
+{
+ ENTRY;
+
+ if (!node)
+ RETURN(NULL);
+
+ if (node->in_left)
+ RETURN(interval_last(node->in_left));
+
+ while (node->in_parent && node_is_left_child(node))
+ node = node->in_parent;
+
+ RETURN(node->in_parent);
+}
+
+enum interval_iter interval_iterate(struct interval_node *root,
+ interval_callback_t func,
+ void *data)
+{
+ struct interval_node *node;
+ enum interval_iter rc = INTERVAL_ITER_CONT;
+ ENTRY;
+
+ interval_for_each(node, root) {
+ rc = func(node, data);
+ if (rc == INTERVAL_ITER_STOP)
+ break;
+ }
+
+ RETURN(rc);
+}
+EXPORT_SYMBOL(interval_iterate);
+
+enum interval_iter interval_iterate_reverse(struct interval_node *root,
+ interval_callback_t func,
+ void *data)
+{
+ struct interval_node *node;
+ enum interval_iter rc = INTERVAL_ITER_CONT;
+ ENTRY;
+
+ interval_for_each_reverse(node, root) {
+ rc = func(node, data);
+ if (rc == INTERVAL_ITER_STOP)
+ break;
+ }
+
+ RETURN(rc);
+}
+EXPORT_SYMBOL(interval_iterate_reverse);
+
+/* try to find a node with same interval in the tree,
+ * if found, return the pointer to the node, otherwise return NULL*/
+struct interval_node *interval_find(struct interval_node *root,
+ struct interval_node_extent *ex)
+{
+ struct interval_node *walk = root;
+ int rc;
+ ENTRY;
+
+ while (walk) {
+ rc = extent_compare(ex, &walk->in_extent);
+ if (rc == 0)
+ break;
+ else if (rc < 0)
+ walk = walk->in_left;
+ else
+ walk = walk->in_right;
+ }
+
+ RETURN(walk);
+}
+EXPORT_SYMBOL(interval_find);
+
+static void __rotate_change_maxhigh(struct interval_node *node,
+ struct interval_node *rotate)
+{
+ __u64 left_max, right_max;
+
+ rotate->in_max_high = node->in_max_high;
+ left_max = node->in_left ? node->in_left->in_max_high : 0;
+ right_max = node->in_right ? node->in_right->in_max_high : 0;
+ node->in_max_high = max_u64(interval_high(node),
+ max_u64(left_max,right_max));
+}
+
+/* The left rotation "pivots" around the link from node to node->right, and
+ * - node will be linked to node->right's left child, and
+ * - node->right's left child will be linked to node's right child. */
+static void __rotate_left(struct interval_node *node,
+ struct interval_node **root)
+{
+ struct interval_node *right = node->in_right;
+ struct interval_node *parent = node->in_parent;
+
+ node->in_right = right->in_left;
+ if (node->in_right)
+ right->in_left->in_parent = node;
+
+ right->in_left = node;
+ right->in_parent = parent;
+ if (parent) {
+ if (node_is_left_child(node))
+ parent->in_left = right;
+ else
+ parent->in_right = right;
+ } else {
+ *root = right;
+ }
+ node->in_parent = right;
+
+ /* update max_high for node and right */
+ __rotate_change_maxhigh(node, right);
+}
+
+/* The right rotation "pivots" around the link from node to node->left, and
+ * - node will be linked to node->left's right child, and
+ * - node->left's right child will be linked to node's left child. */
+static void __rotate_right(struct interval_node *node,
+ struct interval_node **root)
+{
+ struct interval_node *left = node->in_left;
+ struct interval_node *parent = node->in_parent;
+
+ node->in_left = left->in_right;
+ if (node->in_left)
+ left->in_right->in_parent = node;
+ left->in_right = node;
+
+ left->in_parent = parent;
+ if (parent) {
+ if (node_is_right_child(node))
+ parent->in_right = left;
+ else
+ parent->in_left = left;
+ } else {
+ *root = left;
+ }
+ node->in_parent = left;
+
+ /* update max_high for node and left */
+ __rotate_change_maxhigh(node, left);
+}
+
+#define interval_swap(a, b) do { \
+ struct interval_node *c = a; a = b; b = c; \
+} while (0)
+
+/*
+ * Operations INSERT and DELETE, when run on a tree with n keys,
+ * take O(logN) time.Because they modify the tree, the result
+ * may violate the red-black properties.To restore these properties,
+ * we must change the colors of some of the nodes in the tree
+ * and also change the pointer structure.
+ */
+static void interval_insert_color(struct interval_node *node,
+ struct interval_node **root)
+{
+ struct interval_node *parent, *gparent;
+ ENTRY;
+
+ while ((parent = node->in_parent) && node_is_red(parent)) {
+ gparent = parent->in_parent;
+ /* Parent is RED, so gparent must not be NULL */
+ if (node_is_left_child(parent)) {
+ struct interval_node *uncle;
+ uncle = gparent->in_right;
+ if (uncle && node_is_red(uncle)) {
+ uncle->in_color = INTERVAL_BLACK;
+ parent->in_color = INTERVAL_BLACK;
+ gparent->in_color = INTERVAL_RED;
+ node = gparent;
+ continue;
+ }
+
+ if (parent->in_right == node) {
+ __rotate_left(parent, root);
+ interval_swap(node, parent);
+ }
+
+ parent->in_color = INTERVAL_BLACK;
+ gparent->in_color = INTERVAL_RED;
+ __rotate_right(gparent, root);
+ } else {
+ struct interval_node *uncle;
+ uncle = gparent->in_left;
+ if (uncle && node_is_red(uncle)) {
+ uncle->in_color = INTERVAL_BLACK;
+ parent->in_color = INTERVAL_BLACK;
+ gparent->in_color = INTERVAL_RED;
+ node = gparent;
+ continue;
+ }
+
+ if (node_is_left_child(node)) {
+ __rotate_right(parent, root);
+ interval_swap(node, parent);
+ }
+
+ parent->in_color = INTERVAL_BLACK;
+ gparent->in_color = INTERVAL_RED;
+ __rotate_left(gparent, root);
+ }
+ }
+
+ (*root)->in_color = INTERVAL_BLACK;
+ EXIT;
+}
+
+struct interval_node *interval_insert(struct interval_node *node,
+ struct interval_node **root)
+
+{
+ struct interval_node **p, *parent = NULL;
+ ENTRY;
+
+ p = root;
+ while (*p) {
+ parent = *p;
+ if (node_equal(parent, node))
+ RETURN(parent);
+
+ /* max_high field must be updated after each iteration */
+ if (parent->in_max_high < interval_high(node))
+ parent->in_max_high = interval_high(node);
+
+ if (node_compare(node, parent) < 0)
+ p = &parent->in_left;
+ else
+ p = &parent->in_right;
+ }
+
+ /* link node into the tree */
+ node->in_parent = parent;
+ node->in_color = INTERVAL_RED;
+ node->in_left = node->in_right = NULL;
+ *p = node;
+
+ interval_insert_color(node, root);
+
+ RETURN(NULL);
+}
+EXPORT_SYMBOL(interval_insert);
+
+static inline int node_is_black_or_0(struct interval_node *node)
+{
+ return !node || node_is_black(node);
+}
+
+static void interval_erase_color(struct interval_node *node,
+ struct interval_node *parent,
+ struct interval_node **root)
+{
+ struct interval_node *tmp;
+ ENTRY;
+
+ while (node_is_black_or_0(node) && node != *root) {
+ if (parent->in_left == node) {
+ tmp = parent->in_right;
+ if (node_is_red(tmp)) {
+ tmp->in_color = INTERVAL_BLACK;
+ parent->in_color = INTERVAL_RED;
+ __rotate_left(parent, root);
+ tmp = parent->in_right;
+ }
+ if (node_is_black_or_0(tmp->in_left) &&
+ node_is_black_or_0(tmp->in_right)) {
+ tmp->in_color = INTERVAL_RED;
+ node = parent;
+ parent = node->in_parent;
+ } else {
+ if (node_is_black_or_0(tmp->in_right)) {
+ struct interval_node *o_left;
+ if ((o_left = tmp->in_left))
+ o_left->in_color = INTERVAL_BLACK;
+ tmp->in_color = INTERVAL_RED;
+ __rotate_right(tmp, root);
+ tmp = parent->in_right;
+ }
+ tmp->in_color = parent->in_color;
+ parent->in_color = INTERVAL_BLACK;
+ if (tmp->in_right)
+ tmp->in_right->in_color = INTERVAL_BLACK;
+ __rotate_left(parent, root);
+ node = *root;
+ break;
+ }
+ } else {
+ tmp = parent->in_left;
+ if (node_is_red(tmp)) {
+ tmp->in_color = INTERVAL_BLACK;
+ parent->in_color = INTERVAL_RED;
+ __rotate_right(parent, root);
+ tmp = parent->in_left;
+ }
+ if (node_is_black_or_0(tmp->in_left) &&
+ node_is_black_or_0(tmp->in_right)) {
+ tmp->in_color = INTERVAL_RED;
+ node = parent;
+ parent = node->in_parent;
+ } else {
+ if (node_is_black_or_0(tmp->in_left)) {
+ struct interval_node *o_right;
+ if ((o_right = tmp->in_right))
+ o_right->in_color = INTERVAL_BLACK;
+ tmp->in_color = INTERVAL_RED;
+ __rotate_left(tmp, root);
+ tmp = parent->in_left;
+ }
+ tmp->in_color = parent->in_color;
+ parent->in_color = INTERVAL_BLACK;
+ if (tmp->in_left)
+ tmp->in_left->in_color = INTERVAL_BLACK;
+ __rotate_right(parent, root);
+ node = *root;
+ break;
+ }
+ }
+ }
+ if (node)
+ node->in_color = INTERVAL_BLACK;
+ EXIT;
+}
+
+/*
+ * if the @max_high value of @node is changed, this function traverse a path
+ * from node up to the root to update max_high for the whole tree.
+ */
+static void update_maxhigh(struct interval_node *node,
+ __u64 old_maxhigh)
+{
+ __u64 left_max, right_max;
+ ENTRY;
+
+ while (node) {
+ left_max = node->in_left ? node->in_left->in_max_high : 0;
+ right_max = node->in_right ? node->in_right->in_max_high : 0;
+ node->in_max_high = max_u64(interval_high(node),
+ max_u64(left_max, right_max));
+
+ if (node->in_max_high >= old_maxhigh)
+ break;
+ node = node->in_parent;
+ }
+ EXIT;
+}
+
+void interval_erase(struct interval_node *node,
+ struct interval_node **root)
+{
+ struct interval_node *child, *parent;
+ int color;
+ ENTRY;
+
+ if (!node->in_left) {
+ child = node->in_right;
+ } else if (!node->in_right) {
+ child = node->in_left;
+ } else { /* Both left and right child are not NULL */
+ struct interval_node *old = node;
+
+ node = interval_next(node);
+ child = node->in_right;
+ parent = node->in_parent;
+ color = node->in_color;
+
+ if (child)
+ child->in_parent = parent;
+ if (parent == old) {
+ parent->in_right = child;
+ parent = node;
+ } else {
+ parent->in_left = child;
+ }
+
+ node->in_color = old->in_color;
+ node->in_right = old->in_right;
+ node->in_left = old->in_left;
+ node->in_parent = old->in_parent;
+
+ if (old->in_parent) {
+ if (node_is_left_child(old))
+ old->in_parent->in_left = node;
+ else
+ old->in_parent->in_right = node;
+ } else {
+ *root = node;
+ }
+
+ old->in_left->in_parent = node;
+ if (old->in_right)
+ old->in_right->in_parent = node;
+ update_maxhigh(child, node->in_max_high);
+ update_maxhigh(node, old->in_max_high);
+ goto color;
+ }
+ parent = node->in_parent;
+ color = node->in_color;
+
+ if (child)
+ child->in_parent = parent;
+ if (parent) {
+ if (node_is_left_child(node))
+ parent->in_left = child;
+ else
+ parent->in_right = child;
+ } else {
+ *root = child;
+ }
+
+ update_maxhigh(child, node->in_max_high);
+
+color:
+ if (color == INTERVAL_BLACK)
+ interval_erase_color(child, parent, root);
+ EXIT;
+}
+EXPORT_SYMBOL(interval_erase);
+
+static inline int interval_may_overlap(struct interval_node *node,
+ struct interval_node_extent *ext)
+{
+ return (ext->start <= node->in_max_high &&
+ ext->end >= interval_low(node));
+}
+
+/*
+ * This function finds all intervals that overlap interval ext,
+ * and calls func to handle resulted intervals one by one.
+ * in lustre, this function will find all conflicting locks in
+ * the granted queue and add these locks to the ast work list.
+ *
+ * {
+ * if (node == NULL)
+ * return 0;
+ * if (ext->end < interval_low(node)) {
+ * interval_search(node->in_left, ext, func, data);
+ * } else if (interval_may_overlap(node, ext)) {
+ * if (extent_overlapped(ext, &node->in_extent))
+ * func(node, data);
+ * interval_search(node->in_left, ext, func, data);
+ * interval_search(node->in_right, ext, func, data);
+ * }
+ * return 0;
+ * }
+ *
+ */
+enum interval_iter interval_search(struct interval_node *node,
+ struct interval_node_extent *ext,
+ interval_callback_t func,
+ void *data)
+{
+ struct interval_node *parent;
+ enum interval_iter rc = INTERVAL_ITER_CONT;
+
+ LASSERT(ext != NULL);
+ LASSERT(func != NULL);
+
+ while (node) {
+ if (ext->end < interval_low(node)) {
+ if (node->in_left) {
+ node = node->in_left;
+ continue;
+ }
+ } else if (interval_may_overlap(node, ext)) {
+ if (extent_overlapped(ext, &node->in_extent)) {
+ rc = func(node, data);
+ if (rc == INTERVAL_ITER_STOP)
+ break;
+ }
+
+ if (node->in_left) {
+ node = node->in_left;
+ continue;
+ }
+ if (node->in_right) {
+ node = node->in_right;
+ continue;
+ }
+ }
+
+ parent = node->in_parent;
+ while (parent) {
+ if (node_is_left_child(node) &&
+ parent->in_right) {
+ /* If we ever got the left, it means that the
+ * parent met ext->end<interval_low(parent), or
+ * may_overlap(parent). If the former is true,
+ * we needn't go back. So stop early and check
+ * may_overlap(parent) after this loop. */
+ node = parent->in_right;
+ break;
+ }
+ node = parent;
+ parent = parent->in_parent;
+ }
+ if (parent == NULL || !interval_may_overlap(parent, ext))
+ break;
+ }
+
+ return rc;
+}
+EXPORT_SYMBOL(interval_search);
+
+static enum interval_iter interval_overlap_cb(struct interval_node *n,
+ void *args)
+{
+ *(int *)args = 1;
+ return INTERVAL_ITER_STOP;
+}
+
+int interval_is_overlapped(struct interval_node *root,
+ struct interval_node_extent *ext)
+{
+ int has = 0;
+ (void)interval_search(root, ext, interval_overlap_cb, &has);
+ return has;
+}
+EXPORT_SYMBOL(interval_is_overlapped);
+
+/* Don't expand to low. Expanding downwards is expensive, and meaningless to
+ * some extents, because programs seldom do IO backward.
+ *
+ * The recursive algorithm of expanding low:
+ * expand_low {
+ * struct interval_node *tmp;
+ * static __u64 res = 0;
+ *
+ * if (root == NULL)
+ * return res;
+ * if (root->in_max_high < low) {
+ * res = max_u64(root->in_max_high + 1, res);
+ * return res;
+ * } else if (low < interval_low(root)) {
+ * interval_expand_low(root->in_left, low);
+ * return res;
+ * }
+ *
+ * if (interval_high(root) < low)
+ * res = max_u64(interval_high(root) + 1, res);
+ * interval_expand_low(root->in_left, low);
+ * interval_expand_low(root->in_right, low);
+ *
+ * return res;
+ * }
+ *
+ * It's much easy to eliminate the recursion, see interval_search for
+ * an example. -jay
+ */
+static inline __u64 interval_expand_low(struct interval_node *root, __u64 low)
+{
+ /* we only concern the empty tree right now. */
+ if (root == NULL)
+ return 0;
+ return low;
+}
+
+static inline __u64 interval_expand_high(struct interval_node *node, __u64 high)
+{
+ __u64 result = ~0;
+
+ while (node != NULL) {
+ if (node->in_max_high < high)
+ break;
+
+ if (interval_low(node) > high) {
+ result = interval_low(node) - 1;
+ node = node->in_left;
+ } else {
+ node = node->in_right;
+ }
+ }
+
+ return result;
+}
+
+/* expanding the extent based on @ext. */
+void interval_expand(struct interval_node *root,
+ struct interval_node_extent *ext,
+ struct interval_node_extent *limiter)
+{
+ /* The assertion of interval_is_overlapped is expensive because we may
+ * travel many nodes to find the overlapped node. */
+ LASSERT(interval_is_overlapped(root, ext) == 0);
+ if (!limiter || limiter->start < ext->start)
+ ext->start = interval_expand_low(root, ext->start);
+ if (!limiter || limiter->end > ext->end)
+ ext->end = interval_expand_high(root, ext->end);
+ LASSERT(interval_is_overlapped(root, ext) == 0);
+}
+EXPORT_SYMBOL(interval_expand);
git://git.whamcloud.com / fs / lustre-release.git / commitdiff