btrfs-progs: Import interval tree implemenation from Linux v4.0-rc7.

While I had the chance, I compared the rbtre code in btrfs-progs to that of
the latest kernel.  No new bug fixes need importing, however rbtree.h and
rbtree_augmented.h get documentation updates

Signed-off-by: Mark Fasheh <mfasheh@suse.de>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Mark Fasheh 2016-01-20 13:49:25 -08:00 committed by David Sterba
parent 154d28dd99
commit 282dd33a43
3 changed files with 204 additions and 1 deletions

193
interval_tree_generic.h Normal file
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@ -0,0 +1,193 @@
/*
Interval Trees
(C) 2012 Michel Lespinasse <walken@google.com>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
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 for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
include/linux/interval_tree_generic.h
*/
#include <stdbool.h>
#include "rbtree_augmented.h"
/*
* Template for implementing interval trees
*
* ITSTRUCT: struct type of the interval tree nodes
* ITRB: name of struct rb_node field within ITSTRUCT
* ITTYPE: type of the interval endpoints
* ITSUBTREE: name of ITTYPE field within ITSTRUCT holding last-in-subtree
* ITSTART(n): start endpoint of ITSTRUCT node n
* ITLAST(n): last endpoint of ITSTRUCT node n
* ITSTATIC: 'static' or empty
* ITPREFIX: prefix to use for the inline tree definitions
*
* Note - before using this, please consider if non-generic version
* (interval_tree.h) would work for you...
*/
#define INTERVAL_TREE_DEFINE(ITSTRUCT, ITRB, ITTYPE, ITSUBTREE, \
ITSTART, ITLAST, ITSTATIC, ITPREFIX) \
\
/* Callbacks for augmented rbtree insert and remove */ \
\
static inline ITTYPE ITPREFIX ## _compute_subtree_last(ITSTRUCT *node) \
{ \
ITTYPE max = ITLAST(node), subtree_last; \
if (node->ITRB.rb_left) { \
subtree_last = rb_entry(node->ITRB.rb_left, \
ITSTRUCT, ITRB)->ITSUBTREE; \
if (max < subtree_last) \
max = subtree_last; \
} \
if (node->ITRB.rb_right) { \
subtree_last = rb_entry(node->ITRB.rb_right, \
ITSTRUCT, ITRB)->ITSUBTREE; \
if (max < subtree_last) \
max = subtree_last; \
} \
return max; \
} \
\
RB_DECLARE_CALLBACKS(static, ITPREFIX ## _augment, ITSTRUCT, ITRB, \
ITTYPE, ITSUBTREE, ITPREFIX ## _compute_subtree_last) \
\
/* Insert / remove interval nodes from the tree */ \
\
ITSTATIC void ITPREFIX ## _insert(ITSTRUCT *node, struct rb_root *root) \
{ \
struct rb_node **link = &root->rb_node, *rb_parent = NULL; \
ITTYPE start = ITSTART(node), last = ITLAST(node); \
ITSTRUCT *parent; \
\
while (*link) { \
rb_parent = *link; \
parent = rb_entry(rb_parent, ITSTRUCT, ITRB); \
if (parent->ITSUBTREE < last) \
parent->ITSUBTREE = last; \
if (start < ITSTART(parent)) \
link = &parent->ITRB.rb_left; \
else \
link = &parent->ITRB.rb_right; \
} \
\
node->ITSUBTREE = last; \
rb_link_node(&node->ITRB, rb_parent, link); \
rb_insert_augmented(&node->ITRB, root, &ITPREFIX ## _augment); \
} \
\
ITSTATIC void ITPREFIX ## _remove(ITSTRUCT *node, struct rb_root *root) \
{ \
rb_erase_augmented(&node->ITRB, root, &ITPREFIX ## _augment); \
} \
\
/* \
* Iterate over intervals intersecting [start;last] \
* \
* Note that a node's interval intersects [start;last] iff: \
* Cond1: ITSTART(node) <= last \
* and \
* Cond2: start <= ITLAST(node) \
*/ \
\
static ITSTRUCT * \
ITPREFIX ## _subtree_search(ITSTRUCT *node, ITTYPE start, ITTYPE last) \
{ \
while (true) { \
/* \
* Loop invariant: start <= node->ITSUBTREE \
* (Cond2 is satisfied by one of the subtree nodes) \
*/ \
if (node->ITRB.rb_left) { \
ITSTRUCT *left = rb_entry(node->ITRB.rb_left, \
ITSTRUCT, ITRB); \
if (start <= left->ITSUBTREE) { \
/* \
* Some nodes in left subtree satisfy Cond2. \
* Iterate to find the leftmost such node N. \
* If it also satisfies Cond1, that's the \
* match we are looking for. Otherwise, there \
* is no matching interval as nodes to the \
* right of N can't satisfy Cond1 either. \
*/ \
node = left; \
continue; \
} \
} \
if (ITSTART(node) <= last) { /* Cond1 */ \
if (start <= ITLAST(node)) /* Cond2 */ \
return node; /* node is leftmost match */ \
if (node->ITRB.rb_right) { \
node = rb_entry(node->ITRB.rb_right, \
ITSTRUCT, ITRB); \
if (start <= node->ITSUBTREE) \
continue; \
} \
} \
return NULL; /* No match */ \
} \
} \
\
ITSTATIC ITSTRUCT * \
ITPREFIX ## _iter_first(struct rb_root *root, ITTYPE start, ITTYPE last) \
{ \
ITSTRUCT *node; \
\
if (!root->rb_node) \
return NULL; \
node = rb_entry(root->rb_node, ITSTRUCT, ITRB); \
if (node->ITSUBTREE < start) \
return NULL; \
return ITPREFIX ## _subtree_search(node, start, last); \
} \
\
ITSTATIC ITSTRUCT * \
ITPREFIX ## _iter_next(ITSTRUCT *node, ITTYPE start, ITTYPE last) \
{ \
struct rb_node *rb = node->ITRB.rb_right, *prev; \
\
while (true) { \
/* \
* Loop invariants: \
* Cond1: ITSTART(node) <= last \
* rb == node->ITRB.rb_right \
* \
* First, search right subtree if suitable \
*/ \
if (rb) { \
ITSTRUCT *right = rb_entry(rb, ITSTRUCT, ITRB); \
if (start <= right->ITSUBTREE) \
return ITPREFIX ## _subtree_search(right, \
start, last); \
} \
\
/* Move up the tree until we come from a node's left child */ \
do { \
rb = rb_parent(&node->ITRB); \
if (!rb) \
return NULL; \
prev = &node->ITRB; \
node = rb_entry(rb, ITSTRUCT, ITRB); \
rb = node->ITRB.rb_right; \
} while (prev == rb); \
\
/* Check if the node intersects [start;last] */ \
if (last < ITSTART(node)) /* !Cond1 */ \
return NULL; \
else if (start <= ITLAST(node)) /* Cond2 */ \
return node; \
} \
}

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@ -57,7 +57,7 @@ struct rb_root {
#define RB_EMPTY_ROOT(root) ((root)->rb_node == NULL)
/* 'empty' nodes are nodes that are known not to be inserted in an rbree */
/* 'empty' nodes are nodes that are known not to be inserted in an rtbree */
#define RB_EMPTY_NODE(node) \
((node)->__rb_parent_color == (unsigned long)(node))
#define RB_CLEAR_NODE(node) \

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@ -46,6 +46,16 @@ struct rb_augment_callbacks {
extern void __rb_insert_augmented(struct rb_node *node, struct rb_root *root,
void (*augment_rotate)(struct rb_node *old, struct rb_node *new));
/*
* Fixup the rbtree and update the augmented information when rebalancing.
*
* On insertion, the user must update the augmented information on the path
* leading to the inserted node, then call rb_link_node() as usual and
* rb_augment_inserted() instead of the usual rb_insert_color() call.
* If rb_augment_inserted() rebalances the rbtree, it will callback into
* a user provided function to update the augmented information on the
* affected subtrees.
*/
static inline void
rb_insert_augmented(struct rb_node *node, struct rb_root *root,
const struct rb_augment_callbacks *augment)