--- /dev/null
+/*
+ * Copyright (C) 2018 Oracle. All Rights Reserved.
+ *
+ * Author: Darrick J. Wong <darrick.wong@oracle.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 would 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 the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
+#include <stdio.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <assert.h>
+#include <inttypes.h>
+#include <pthread.h>
+#include "platform_defs.h"
+#include "avl64.h"
+#include "list.h"
+#include "bitmap.h"
+
+/*
+ * Space Efficient Bitmap
+ *
+ * Implements a space-efficient bitmap. We use an AVL tree to manage
+ * extent records that tell us which ranges are set; the bitmap key is
+ * an arbitrary uint64_t. The usual bitmap operations (set, clear,
+ * test, test and set) are supported, plus we can iterate set ranges.
+ */
+
+#define avl_for_each_range_safe(pos, n, l, first, last) \
+ for (pos = (first), n = pos->avl_nextino, l = (last)->avl_nextino; pos != (l); \
+ pos = n, n = pos ? pos->avl_nextino : NULL)
+
+#define avl_for_each_safe(tree, pos, n) \
+ for (pos = (tree)->avl_firstino, n = pos ? pos->avl_nextino : NULL; \
+ pos != NULL; \
+ pos = n, n = pos ? pos->avl_nextino : NULL)
+
+#define avl_for_each(tree, pos) \
+ for (pos = (tree)->avl_firstino; pos != NULL; pos = pos->avl_nextino)
+
+struct bitmap_node {
+ struct avl64node btn_node;
+ uint64_t btn_start;
+ uint64_t btn_length;
+};
+
+static uint64_t
+extent_start(
+ struct avl64node *node)
+{
+ struct bitmap_node *btn;
+
+ btn = container_of(node, struct bitmap_node, btn_node);
+ return btn->btn_start;
+}
+
+static uint64_t
+extent_end(
+ struct avl64node *node)
+{
+ struct bitmap_node *btn;
+
+ btn = container_of(node, struct bitmap_node, btn_node);
+ return btn->btn_start + btn->btn_length;
+}
+
+static struct avl64ops bitmap_ops = {
+ extent_start,
+ extent_end,
+};
+
+/* Initialize a bitmap. */
+bool
+bitmap_init(
+ struct bitmap **bmapp)
+{
+ struct bitmap *bmap;
+
+ bmap = calloc(1, sizeof(struct bitmap));
+ if (!bmap)
+ return false;
+ bmap->bt_tree = malloc(sizeof(struct avl64tree_desc));
+ if (!bmap->bt_tree) {
+ free(bmap);
+ return false;
+ }
+
+ pthread_mutex_init(&bmap->bt_lock, NULL);
+ avl64_init_tree(bmap->bt_tree, &bitmap_ops);
+ *bmapp = bmap;
+
+ return true;
+}
+
+/* Free a bitmap. */
+void
+bitmap_free(
+ struct bitmap **bmapp)
+{
+ struct bitmap *bmap;
+ struct avl64node *node;
+ struct avl64node *n;
+ struct bitmap_node *ext;
+
+ bmap = *bmapp;
+ avl_for_each_safe(bmap->bt_tree, node, n) {
+ ext = container_of(node, struct bitmap_node, btn_node);
+ free(ext);
+ }
+ free(bmap->bt_tree);
+ *bmapp = NULL;
+}
+
+/* Create a new bitmap extent node. */
+static struct bitmap_node *
+bitmap_node_init(
+ uint64_t start,
+ uint64_t len)
+{
+ struct bitmap_node *ext;
+
+ ext = malloc(sizeof(struct bitmap_node));
+ if (!ext)
+ return NULL;
+
+ ext->btn_node.avl_nextino = NULL;
+ ext->btn_start = start;
+ ext->btn_length = len;
+
+ return ext;
+}
+
+/* Set a region of bits (locked). */
+static bool
+__bitmap_set(
+ struct bitmap *bmap,
+ uint64_t start,
+ uint64_t length)
+{
+ struct avl64node *firstn;
+ struct avl64node *lastn;
+ struct avl64node *pos;
+ struct avl64node *n;
+ struct avl64node *l;
+ struct bitmap_node *ext;
+ uint64_t new_start;
+ uint64_t new_length;
+ struct avl64node *node;
+ bool res = true;
+
+ /* Find any existing nodes adjacent or within that range. */
+ avl64_findranges(bmap->bt_tree, start - 1, start + length + 1,
+ &firstn, &lastn);
+
+ /* Nothing, just insert a new extent. */
+ if (firstn == NULL && lastn == NULL) {
+ ext = bitmap_node_init(start, length);
+ if (!ext)
+ return false;
+
+ node = avl64_insert(bmap->bt_tree, &ext->btn_node);
+ if (node == NULL) {
+ free(ext);
+ errno = EEXIST;
+ return false;
+ }
+
+ return true;
+ }
+
+ assert(firstn != NULL && lastn != NULL);
+ new_start = start;
+ new_length = length;
+
+ avl_for_each_range_safe(pos, n, l, firstn, lastn) {
+ ext = container_of(pos, struct bitmap_node, btn_node);
+
+ /* Bail if the new extent is contained within an old one. */
+ if (ext->btn_start <= start &&
+ ext->btn_start + ext->btn_length >= start + length)
+ return res;
+
+ /* Check for overlapping and adjacent extents. */
+ if (ext->btn_start + ext->btn_length >= start ||
+ ext->btn_start <= start + length) {
+ if (ext->btn_start < start) {
+ new_start = ext->btn_start;
+ new_length += ext->btn_length;
+ }
+
+ if (ext->btn_start + ext->btn_length >
+ new_start + new_length)
+ new_length = ext->btn_start + ext->btn_length -
+ new_start;
+
+ avl64_delete(bmap->bt_tree, pos);
+ free(ext);
+ }
+ }
+
+ ext = bitmap_node_init(new_start, new_length);
+ if (!ext)
+ return false;
+
+ node = avl64_insert(bmap->bt_tree, &ext->btn_node);
+ if (node == NULL) {
+ free(ext);
+ errno = EEXIST;
+ return false;
+ }
+
+ return res;
+}
+
+/* Set a region of bits. */
+bool
+bitmap_set(
+ struct bitmap *bmap,
+ uint64_t start,
+ uint64_t length)
+{
+ bool res;
+
+ pthread_mutex_lock(&bmap->bt_lock);
+ res = __bitmap_set(bmap, start, length);
+ pthread_mutex_unlock(&bmap->bt_lock);
+
+ return res;
+}
+
+#if 0 /* Unused, provided for completeness. */
+/* Clear a region of bits. */
+bool
+bitmap_clear(
+ struct bitmap *bmap,
+ uint64_t start,
+ uint64_t len)
+{
+ struct avl64node *firstn;
+ struct avl64node *lastn;
+ struct avl64node *pos;
+ struct avl64node *n;
+ struct avl64node *l;
+ struct bitmap_node *ext;
+ uint64_t new_start;
+ uint64_t new_length;
+ struct avl64node *node;
+ int stat;
+
+ pthread_mutex_lock(&bmap->bt_lock);
+ /* Find any existing nodes over that range. */
+ avl64_findranges(bmap->bt_tree, start, start + len, &firstn, &lastn);
+
+ /* Nothing, we're done. */
+ if (firstn == NULL && lastn == NULL) {
+ pthread_mutex_unlock(&bmap->bt_lock);
+ return true;
+ }
+
+ assert(firstn != NULL && lastn != NULL);
+
+ /* Delete or truncate everything in sight. */
+ avl_for_each_range_safe(pos, n, l, firstn, lastn) {
+ ext = container_of(pos, struct bitmap_node, btn_node);
+
+ stat = 0;
+ if (ext->btn_start < start)
+ stat |= 1;
+ if (ext->btn_start + ext->btn_length > start + len)
+ stat |= 2;
+ switch (stat) {
+ case 0:
+ /* Extent totally within range; delete. */
+ avl64_delete(bmap->bt_tree, pos);
+ free(ext);
+ break;
+ case 1:
+ /* Extent is left-adjacent; truncate. */
+ ext->btn_length = start - ext->btn_start;
+ break;
+ case 2:
+ /* Extent is right-adjacent; move it. */
+ ext->btn_length = ext->btn_start + ext->btn_length -
+ (start + len);
+ ext->btn_start = start + len;
+ break;
+ case 3:
+ /* Extent overlaps both ends. */
+ ext->btn_length = start - ext->btn_start;
+ new_start = start + len;
+ new_length = ext->btn_start + ext->btn_length -
+ new_start;
+
+ ext = bitmap_node_init(new_start, new_length);
+ if (!ext)
+ return false;
+
+ node = avl64_insert(bmap->bt_tree, &ext->btn_node);
+ if (node == NULL) {
+ errno = EEXIST;
+ return false;
+ }
+ break;
+ }
+ }
+
+ pthread_mutex_unlock(&bmap->bt_lock);
+ return true;
+}
+#endif
+
+#ifdef DEBUG
+/* Iterate the set regions of this bitmap. */
+bool
+bitmap_iterate(
+ struct bitmap *bmap,
+ bool (*fn)(uint64_t, uint64_t, void *),
+ void *arg)
+{
+ struct avl64node *node;
+ struct bitmap_node *ext;
+ bool moveon = true;
+
+ pthread_mutex_lock(&bmap->bt_lock);
+ avl_for_each(bmap->bt_tree, node) {
+ ext = container_of(node, struct bitmap_node, btn_node);
+ moveon = fn(ext->btn_start, ext->btn_length, arg);
+ if (!moveon)
+ break;
+ }
+ pthread_mutex_unlock(&bmap->bt_lock);
+
+ return moveon;
+}
+#endif
+
+/* Do any bitmap extents overlap the given one? (locked) */
+static bool
+__bitmap_test(
+ struct bitmap *bmap,
+ uint64_t start,
+ uint64_t len)
+{
+ struct avl64node *firstn;
+ struct avl64node *lastn;
+
+ /* Find any existing nodes over that range. */
+ avl64_findranges(bmap->bt_tree, start, start + len, &firstn, &lastn);
+
+ return firstn != NULL && lastn != NULL;
+}
+
+/* Is any part of this range set? */
+bool
+bitmap_test(
+ struct bitmap *bmap,
+ uint64_t start,
+ uint64_t len)
+{
+ bool res;
+
+ pthread_mutex_lock(&bmap->bt_lock);
+ res = __bitmap_test(bmap, start, len);
+ pthread_mutex_unlock(&bmap->bt_lock);
+
+ return res;
+}
+
+/* Are none of the bits set? */
+bool
+bitmap_empty(
+ struct bitmap *bmap)
+{
+ return bmap->bt_tree->avl_firstino == NULL;
+}
+
+#ifdef DEBUG
+static bool
+bitmap_dump_fn(
+ uint64_t startblock,
+ uint64_t blockcount,
+ void *arg)
+{
+ printf("%"PRIu64":%"PRIu64"\n", startblock, blockcount);
+ return true;
+}
+
+/* Dump bitmap. */
+void
+bitmap_dump(
+ struct bitmap *bmap)
+{
+ printf("BITMAP DUMP %p\n", bmap);
+ bitmap_iterate(bmap, bitmap_dump_fn, NULL);
+ printf("BITMAP DUMP DONE\n");
+}
+#endif
projects / thirdparty / xfsprogs-dev.git / commitdiff
