staging: add Lustre file system client support

Lustre is the most deployed distributed file system
in the HPC (High Performance Computing) world. The patch
adds its client side support.

The code is not very clean and needs to live in drivers/staging
for some time for continuing cleanup work. See
drivers/staging/lustre/TODO for details.

The code is based on Lustre master commit faefbfc04

commit faefbfc0460bc00f2ee4c1c1c86aa1e39b9eea49
Author: Alex Zhuravlev <alexey.zhuravlev@intel.com>
Date:   Tue Apr 30 23:05:21 2013 +0400

    LU-3244 utils: tunefs.lustre should preserve virgin label

Plus a few under-review patches on Whamcloud gerrit:
3.8 kernel support:
http://review.whamcloud.com/#change,5973
http://review.whamcloud.com/#change,5974
http://review.whamcloud.com/#change,5768
http://review.whamcloud.com/#change,5781
http://review.whamcloud.com/#change,5763
http://review.whamcloud.com/#change,5613
http://review.whamcloud.com/#change,5655

3.9 kernel support:
http://review.whamcloud.com/#change,5898
http://review.whamcloud.com/#change,5899

Kconfig/Kbuild:
http://review.whamcloud.com/#change,4646
http://review.whamcloud.com/#change,4644

libcfs cleanup:
http://review.whamcloud.com/#change,2831
http://review.whamcloud.com/#change,4775
http://review.whamcloud.com/#change,4776
http://review.whamcloud.com/#change,4777
http://review.whamcloud.com/#change,4778
http://review.whamcloud.com/#change,4779
http://review.whamcloud.com/#change,4780

All starting/trailing whitespaces are removed, to match kernel
coding style. Also ran scripts/cleanfile on all lustre source files.

[maked the Kconfig depend on BROKEN as the recent procfs changes causes
this to fail - gregkh]

Signed-off-by: Peng Tao <tao.peng@emc.com>
Signed-off-by: Andreas Dilger <andreas.dilger@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 764 insertions, 0 deletions

diff --git a/drivers/staging/lustre/lustre/ldlm/interval_tree.c b/drivers/staging/lustre/lustre/ldlm/interval_tree.c
new file mode 100644
index 0000000..ce90c7e
--- /dev/null
+++ b/drivers/staging/lustre/lustre/ldlm/interval_tree.c
@@ -0,0 +1,764 @@
+/*
+ * GPL HEADER START
+ *
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 only,
+ * as published by the Free Software Foundation.
+ *
+ * This program 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 GNU
+ * General Public License version 2 for more details (a copy is included
+ * in the LICENSE file that accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License
+ * version 2 along with this program; If not, see
+ * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
+ *
+ * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ *
+ * GPL HEADER END
+ */
+/*
+ * Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Use is subject to license terms.
+ */
+/*
+ * This file is part of Lustre, http://www.lustre.org/
+ * Lustre is a trademark of Sun Microsystems, Inc.
+ *
+ * lustre/ldlm/interval_tree.c
+ *
+ * Interval tree library used by ldlm extent lock code
+ *
+ * Author: Huang Wei <huangwei@clusterfs.com>
+ * Author: Jay Xiong <jinshan.xiong@sun.com>
+ */
+# include <lustre_dlm.h>
+#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;
+
+	LASSERT(!interval_is_intree(node));
+	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);
+	node->in_intree = 1;
+
+	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;
+
+	LASSERT(interval_is_intree(node));
+	node->in_intree = 0;
+	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;
+		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 ? : parent, node->in_max_high);
+		update_maxhigh(node, old->in_max_high);
+		if (parent == old)
+			 parent = node;
+		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 ? : parent, 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);