From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754103Ab1HYPhJ (ORCPT ); Thu, 25 Aug 2011 11:37:09 -0400 Received: from mail09.linbit.com ([212.69.161.110]:32955 "EHLO mail09.linbit.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753216Ab1HYPJD (ORCPT ); Thu, 25 Aug 2011 11:09:03 -0400 From: Philipp Reisner To: linux-kernel@vger.kernel.org, Jens Axboe Cc: drbd-dev@lists.linbit.com Subject: [PATCH 013/118] drbd: Add interval tree data structure Date: Thu, 25 Aug 2011 17:07:09 +0200 Message-Id: <1314284934-17999-14-git-send-email-philipp.reisner@linbit.com> X-Mailer: git-send-email 1.7.4.1 In-Reply-To: <1314284934-17999-1-git-send-email-philipp.reisner@linbit.com> References: <1314284934-17999-1-git-send-email-philipp.reisner@linbit.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Andreas Gruenbacher Signed-off-by: Philipp Reisner Signed-off-by: Lars Ellenberg --- drivers/block/drbd/Makefile | 1 + drivers/block/drbd/drbd_interval.c | 156 ++++++++++++++++++++++++++++++++++++ drivers/block/drbd/drbd_interval.h | 31 +++++++ 3 files changed, 188 insertions(+), 0 deletions(-) create mode 100644 drivers/block/drbd/drbd_interval.c create mode 100644 drivers/block/drbd/drbd_interval.h diff --git a/drivers/block/drbd/Makefile b/drivers/block/drbd/Makefile index 0d3f337..cacbb04 100644 --- a/drivers/block/drbd/Makefile +++ b/drivers/block/drbd/Makefile @@ -1,5 +1,6 @@ drbd-y := drbd_bitmap.o drbd_proc.o drbd-y += drbd_worker.o drbd_receiver.o drbd_req.o drbd_actlog.o drbd-y += drbd_main.o drbd_strings.o drbd_nl.o +drbd-y += drbd_interval.o obj-$(CONFIG_BLK_DEV_DRBD) += drbd.o diff --git a/drivers/block/drbd/drbd_interval.c b/drivers/block/drbd/drbd_interval.c new file mode 100644 index 0000000..2511dd9 --- /dev/null +++ b/drivers/block/drbd/drbd_interval.c @@ -0,0 +1,156 @@ +#include "drbd_interval.h" + +/** + * interval_end - return end of @node + */ +static inline +sector_t interval_end(struct rb_node *node) +{ + struct drbd_interval *this = rb_entry(node, struct drbd_interval, rb); + return this->end; +} + +/** + * update_interval_end - recompute end of @node + * + * The end of an interval is the highest (start + (size >> 9)) value of this + * node and of its children. Called for @node and its parents whenever the end + * may have changed. + */ +static void +update_interval_end(struct rb_node *node, void *__unused) +{ + struct drbd_interval *this = rb_entry(node, struct drbd_interval, rb); + sector_t end; + + end = this->sector + (this->size >> 9); + if (node->rb_left) { + sector_t left = interval_end(node->rb_left); + if (left > end) + end = left; + } + if (node->rb_right) { + sector_t right = interval_end(node->rb_right); + if (right > end) + end = right; + } + this->end = end; +} + +/** + * drbd_insert_interval - insert a new interval into a tree + */ +bool +drbd_insert_interval(struct rb_root *root, struct drbd_interval *this) +{ + struct rb_node **new = &root->rb_node, *parent = NULL; + + BUG_ON(!IS_ALIGNED(this->size, 512)); + + while (*new) { + struct drbd_interval *here = + rb_entry(*new, struct drbd_interval, rb); + + parent = *new; + if (this->sector < here->sector) + new = &(*new)->rb_left; + else if (this->sector > here->sector) + new = &(*new)->rb_right; + else if (this < here) + new = &(*new)->rb_left; + else if (this->sector > here->sector) + new = &(*new)->rb_right; + return false; + } + + rb_link_node(&this->rb, parent, new); + rb_insert_color(&this->rb, root); + rb_augment_insert(&this->rb, update_interval_end, NULL); + return true; +} + +/** + * drbd_contains_interval - check if a tree contains a given interval + * @sector: start sector of @interval + * @interval: may not be a valid pointer + * + * Returns if the tree contains the node @interval with start sector @start. + * Does not dereference @interval until @interval is known to be a valid object + * in @tree. Returns %false if @interval is in the tree but with a different + * sector number. + */ +bool +drbd_contains_interval(struct rb_root *root, sector_t sector, + struct drbd_interval *interval) +{ + struct rb_node *node = root->rb_node; + + while (node) { + struct drbd_interval *here = + rb_entry(node, struct drbd_interval, rb); + + if (sector < here->sector) + node = node->rb_left; + else if (sector > here->sector) + node = node->rb_right; + else if (interval < here) + node = node->rb_left; + else if (interval > here) + node = node->rb_right; + else + return interval->sector == sector; + } + return false; +} + +/** + * drbd_remove_interval - remove an interval from a tree + */ +void +drbd_remove_interval(struct rb_root *root, struct drbd_interval *this) +{ + struct rb_node *deepest; + + deepest = rb_augment_erase_begin(&this->rb); + rb_erase(&this->rb, root); + rb_augment_erase_end(deepest, update_interval_end, NULL); +} + +/** + * drbd_find_overlap - search for an interval overlapping with [sector, sector + size) + * @sector: start sector + * @size: size, aligned to 512 bytes + * + * Returns the interval overlapping with [sector, sector + size), or NULL. + * When there is more than one overlapping interval in the tree, the interval + * with the lowest start sector is returned. + */ +struct drbd_interval * +drbd_find_overlap(struct rb_root *root, sector_t sector, unsigned int size) +{ + struct rb_node *node = root->rb_node; + struct drbd_interval *overlap = NULL; + sector_t end = sector + (size >> 9); + + BUG_ON(!IS_ALIGNED(size, 512)); + + while (node) { + struct drbd_interval *here = + rb_entry(node, struct drbd_interval, rb); + + if (node->rb_left && + sector < interval_end(node->rb_left)) { + /* Overlap if any must be on left side */ + node = node->rb_left; + } else if (here->sector < end && + sector < here->sector + (here->size >> 9)) { + overlap = here; + break; + } else if (sector >= here->sector) { + /* Overlap if any must be on right side */ + node = node->rb_right; + } else + break; + } + return overlap; +} diff --git a/drivers/block/drbd/drbd_interval.h b/drivers/block/drbd/drbd_interval.h new file mode 100644 index 0000000..bf8dcf7 --- /dev/null +++ b/drivers/block/drbd/drbd_interval.h @@ -0,0 +1,31 @@ +#ifndef __DRBD_INTERVAL_H +#define __DRBD_INTERVAL_H + +#include +#include + +struct drbd_interval { + struct rb_node rb; + sector_t sector; /* start sector of the interval */ + unsigned int size; /* size in bytes */ + sector_t end; /* highest interval end in subtree */ +}; + +static inline void drbd_clear_interval(struct drbd_interval *i) +{ + RB_CLEAR_NODE(&i->rb); +} + +static inline bool drbd_interval_empty(struct drbd_interval *i) +{ + return RB_EMPTY_NODE(&i->rb); +} + +bool drbd_insert_interval(struct rb_root *, struct drbd_interval *); +struct drbd_interval *drbd_find_interval(struct rb_root *, sector_t, + struct drbd_interval *); +void drbd_remove_interval(struct rb_root *, struct drbd_interval *); +struct drbd_interval *drbd_find_overlap(struct rb_root *, sector_t, + unsigned int); + +#endif /* __DRBD_INTERVAL_H */ -- 1.7.4.1