From cec572daccafa1e912cbed363df6f84687778c6f Mon Sep 17 00:00:00 2001 From: Nicholas D Steeves Date: Sat, 23 Apr 2016 00:41:30 +0100 Subject: btrfs-progs (4.4.1-1.1) unstable; urgency=medium * Non-maintainer upload. * New upstream release. * Rename package to btrfs-progs (Closes: #780081) * Update standards version to 3.9.7 (no changes needed). * debian/control: Add "Breaks" per Gianfranco Costamagna's suggestion * Change lintian override to reflect package rename * Switch from using postinst and postrm to using triggers per Christian Seiler's recommendation. # imported from the archive --- radix-tree.c | 849 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 849 insertions(+) create mode 100644 radix-tree.c (limited to 'radix-tree.c') diff --git a/radix-tree.c b/radix-tree.c new file mode 100644 index 00000000..f259ab56 --- /dev/null +++ b/radix-tree.c @@ -0,0 +1,849 @@ +/* + * Copyright (C) 2007 Oracle. All rights reserved. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public + * License v2 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 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 021110-1307, USA. + */ + +/* + * Copyright (C) 2001 Momchil Velikov + * Portions Copyright (C) 2001 Christoph Hellwig + * Copyright (C) 2005 SGI, Christoph Lameter + * + * 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, 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., 675 Mass Ave, Cambridge, MA 02139, USA. + */ + +#include "kerncompat.h" +#include "radix-tree.h" +#ifdef __KERNEL__ +#define RADIX_TREE_MAP_SHIFT (CONFIG_BASE_SMALL ? 4 : 6) +#else +#define RADIX_TREE_MAP_SHIFT 3 /* For more stressful testing */ +#endif + +#define RADIX_TREE_MAP_SIZE (1UL << RADIX_TREE_MAP_SHIFT) +#define RADIX_TREE_MAP_MASK (RADIX_TREE_MAP_SIZE-1) + +#define RADIX_TREE_TAG_LONGS \ + ((RADIX_TREE_MAP_SIZE + BITS_PER_LONG - 1) / BITS_PER_LONG) + +struct radix_tree_node { + unsigned int count; + void *slots[RADIX_TREE_MAP_SIZE]; + unsigned long tags[RADIX_TREE_MAX_TAGS][RADIX_TREE_TAG_LONGS]; +}; + +struct radix_tree_path { + struct radix_tree_node *node; + int offset; +}; + +#define RADIX_TREE_INDEX_BITS (8 /* CHAR_BIT */ * sizeof(unsigned long)) +#define RADIX_TREE_MAX_PATH (RADIX_TREE_INDEX_BITS/RADIX_TREE_MAP_SHIFT + 2) + +static unsigned long height_to_maxindex[RADIX_TREE_MAX_PATH] __read_mostly; + +/* + * Per-cpu pool of preloaded nodes + */ +struct radix_tree_preload { + int nr; + struct radix_tree_node *nodes[RADIX_TREE_MAX_PATH]; +}; +static struct radix_tree_preload radix_tree_preloads = { 0, }; + +static int internal_nodes = 0; +/* + * This assumes that the caller has performed appropriate preallocation, and + * that the caller has pinned this thread of control to the current CPU. + */ +static struct radix_tree_node * +radix_tree_node_alloc(struct radix_tree_root *root) +{ + struct radix_tree_node *ret; + ret = malloc(sizeof(struct radix_tree_node)); + if (ret) { + memset(ret, 0, sizeof(struct radix_tree_node)); + internal_nodes++; + } + return ret; +} + +static inline void +radix_tree_node_free(struct radix_tree_node *node) +{ + internal_nodes--; + free(node); +} + +/* + * Load up this CPU's radix_tree_node buffer with sufficient objects to + * ensure that the addition of a single element in the tree cannot fail. On + * success, return zero, with preemption disabled. On error, return -ENOMEM + * with preemption not disabled. + */ +int radix_tree_preload(gfp_t gfp_mask) +{ + struct radix_tree_preload *rtp; + struct radix_tree_node *node; + int ret = -ENOMEM; + + preempt_disable(); + rtp = &__get_cpu_var(radix_tree_preloads); + while (rtp->nr < ARRAY_SIZE(rtp->nodes)) { + preempt_enable(); + node = radix_tree_node_alloc(NULL); + if (node == NULL) + goto out; + preempt_disable(); + rtp = &__get_cpu_var(radix_tree_preloads); + if (rtp->nr < ARRAY_SIZE(rtp->nodes)) + rtp->nodes[rtp->nr++] = node; + else + radix_tree_node_free(node); + } + ret = 0; +out: + return ret; +} + +static inline void tag_set(struct radix_tree_node *node, unsigned int tag, + int offset) +{ + __set_bit(offset, node->tags[tag]); +} + +static inline void tag_clear(struct radix_tree_node *node, unsigned int tag, + int offset) +{ + __clear_bit(offset, node->tags[tag]); +} + +static inline int tag_get(struct radix_tree_node *node, unsigned int tag, + int offset) +{ + return test_bit(offset, node->tags[tag]); +} + +static inline void root_tag_set(struct radix_tree_root *root, unsigned int tag) +{ + root->gfp_mask |= (__force gfp_t)(1 << (tag + __GFP_BITS_SHIFT)); +} + + +static inline void root_tag_clear(struct radix_tree_root *root, unsigned int tag) +{ + root->gfp_mask &= (__force gfp_t)~(1 << (tag + __GFP_BITS_SHIFT)); +} + +static inline void root_tag_clear_all(struct radix_tree_root *root) +{ + root->gfp_mask &= __GFP_BITS_MASK; +} + +static inline int root_tag_get(struct radix_tree_root *root, unsigned int tag) +{ + return (__force unsigned)root->gfp_mask & (1 << (tag + __GFP_BITS_SHIFT)); +} + +/* + * Returns 1 if any slot in the node has this tag set. + * Otherwise returns 0. + */ +static inline int any_tag_set(struct radix_tree_node *node, unsigned int tag) +{ + int idx; + for (idx = 0; idx < RADIX_TREE_TAG_LONGS; idx++) { + if (node->tags[tag][idx]) + return 1; + } + return 0; +} + +/* + * Return the maximum key which can be store into a + * radix tree with height HEIGHT. + */ +static inline unsigned long radix_tree_maxindex(unsigned int height) +{ + return height_to_maxindex[height]; +} + +/* + * Extend a radix tree so it can store key @index. + */ +static int radix_tree_extend(struct radix_tree_root *root, unsigned long index) +{ + struct radix_tree_node *node; + unsigned int height; + int tag; + + /* Figure out what the height should be. */ + height = root->height + 1; + while (index > radix_tree_maxindex(height)) + height++; + + if (root->rnode == NULL) { + root->height = height; + goto out; + } + + do { + if (!(node = radix_tree_node_alloc(root))) + return -ENOMEM; + + /* Increase the height. */ + node->slots[0] = root->rnode; + + /* Propagate the aggregated tag info into the new root */ + for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) { + if (root_tag_get(root, tag)) + tag_set(node, tag, 0); + } + + node->count = 1; + root->rnode = node; + root->height++; + } while (height > root->height); +out: + return 0; +} + +/** + * radix_tree_insert - insert into a radix tree + * @root: radix tree root + * @index: index key + * @item: item to insert + * + * Insert an item into the radix tree at position @index. + */ +int radix_tree_insert(struct radix_tree_root *root, + unsigned long index, void *item) +{ + struct radix_tree_node *node = NULL, *slot; + unsigned int height, shift; + int offset; + int error; + + /* Make sure the tree is high enough. */ + if (index > radix_tree_maxindex(root->height)) { + error = radix_tree_extend(root, index); + if (error) + return error; + } + + slot = root->rnode; + height = root->height; + shift = (height-1) * RADIX_TREE_MAP_SHIFT; + + offset = 0; /* uninitialised var warning */ + while (height > 0) { + if (slot == NULL) { + /* Have to add a child node. */ + if (!(slot = radix_tree_node_alloc(root))) + return -ENOMEM; + if (node) { + node->slots[offset] = slot; + node->count++; + } else + root->rnode = slot; + } + + /* Go a level down */ + offset = (index >> shift) & RADIX_TREE_MAP_MASK; + node = slot; + slot = node->slots[offset]; + shift -= RADIX_TREE_MAP_SHIFT; + height--; + } + + if (slot != NULL) + return -EEXIST; + + if (node) { + node->count++; + node->slots[offset] = item; + BUG_ON(tag_get(node, 0, offset)); + BUG_ON(tag_get(node, 1, offset)); + } else { + root->rnode = item; + BUG_ON(root_tag_get(root, 0)); + BUG_ON(root_tag_get(root, 1)); + } + + return 0; +} + +static inline void **__lookup_slot(struct radix_tree_root *root, + unsigned long index) +{ + unsigned int height, shift; + struct radix_tree_node **slot; + + height = root->height; + + if (index > radix_tree_maxindex(height)) + return NULL; + + if (height == 0 && root->rnode) + return (void *)&root->rnode; + + shift = (height-1) * RADIX_TREE_MAP_SHIFT; + slot = &root->rnode; + + while (height > 0) { + if (*slot == NULL) + return NULL; + + slot = (struct radix_tree_node **) + ((*slot)->slots + + ((index >> shift) & RADIX_TREE_MAP_MASK)); + shift -= RADIX_TREE_MAP_SHIFT; + height--; + } + + return (void **)slot; +} + +/** + * radix_tree_lookup_slot - lookup a slot in a radix tree + * @root: radix tree root + * @index: index key + * + * Lookup the slot corresponding to the position @index in the radix tree + * @root. This is useful for update-if-exists operations. + */ +void **radix_tree_lookup_slot(struct radix_tree_root *root, unsigned long index) +{ + return __lookup_slot(root, index); +} + +/** + * radix_tree_lookup - perform lookup operation on a radix tree + * @root: radix tree root + * @index: index key + * + * Lookup the item at the position @index in the radix tree @root. + */ +void *radix_tree_lookup(struct radix_tree_root *root, unsigned long index) +{ + void **slot; + + slot = __lookup_slot(root, index); + return slot != NULL ? *slot : NULL; +} + +/** + * radix_tree_tag_set - set a tag on a radix tree node + * @root: radix tree root + * @index: index key + * @tag: tag index + * + * Set the search tag (which must be < RADIX_TREE_MAX_TAGS) + * corresponding to @index in the radix tree. From + * the root all the way down to the leaf node. + * + * Returns the address of the tagged item. Setting a tag on a not-present + * item is a bug. + */ +void *radix_tree_tag_set(struct radix_tree_root *root, + unsigned long index, unsigned int tag) +{ + unsigned int height, shift; + struct radix_tree_node *slot; + + height = root->height; + BUG_ON(index > radix_tree_maxindex(height)); + + slot = root->rnode; + shift = (height - 1) * RADIX_TREE_MAP_SHIFT; + + while (height > 0) { + int offset; + + offset = (index >> shift) & RADIX_TREE_MAP_MASK; + if (!tag_get(slot, tag, offset)) + tag_set(slot, tag, offset); + slot = slot->slots[offset]; + BUG_ON(slot == NULL); + shift -= RADIX_TREE_MAP_SHIFT; + height--; + } + + /* set the root's tag bit */ + if (slot && !root_tag_get(root, tag)) + root_tag_set(root, tag); + + return slot; +} + +/** + * radix_tree_tag_clear - clear a tag on a radix tree node + * @root: radix tree root + * @index: index key + * @tag: tag index + * + * Clear the search tag (which must be < RADIX_TREE_MAX_TAGS) + * corresponding to @index in the radix tree. If + * this causes the leaf node to have no tags set then clear the tag in the + * next-to-leaf node, etc. + * + * Returns the address of the tagged item on success, else NULL. ie: + * has the same return value and semantics as radix_tree_lookup(). + */ +void *radix_tree_tag_clear(struct radix_tree_root *root, + unsigned long index, unsigned int tag) +{ + struct radix_tree_path path[RADIX_TREE_MAX_PATH], *pathp = path; + struct radix_tree_node *slot = NULL; + unsigned int height, shift; + + height = root->height; + if (index > radix_tree_maxindex(height)) + goto out; + + shift = (height - 1) * RADIX_TREE_MAP_SHIFT; + pathp->node = NULL; + slot = root->rnode; + + while (height > 0) { + int offset; + + if (slot == NULL) + goto out; + + offset = (index >> shift) & RADIX_TREE_MAP_MASK; + pathp[1].offset = offset; + pathp[1].node = slot; + slot = slot->slots[offset]; + pathp++; + shift -= RADIX_TREE_MAP_SHIFT; + height--; + } + + if (slot == NULL) + goto out; + + while (pathp->node) { + if (!tag_get(pathp->node, tag, pathp->offset)) + goto out; + tag_clear(pathp->node, tag, pathp->offset); + if (any_tag_set(pathp->node, tag)) + goto out; + pathp--; + } + + /* clear the root's tag bit */ + if (root_tag_get(root, tag)) + root_tag_clear(root, tag); + +out: + return slot; +} + +#ifndef __KERNEL__ /* Only the test harness uses this at present */ +/** + * radix_tree_tag_get - get a tag on a radix tree node + * @root: radix tree root + * @index: index key + * @tag: tag index (< RADIX_TREE_MAX_TAGS) + * + * Return values: + * + * 0: tag not present or not set + * 1: tag set + */ +int radix_tree_tag_get(struct radix_tree_root *root, + unsigned long index, unsigned int tag) +{ + unsigned int height, shift; + struct radix_tree_node *slot; + int saw_unset_tag = 0; + + height = root->height; + if (index > radix_tree_maxindex(height)) + return 0; + + /* check the root's tag bit */ + if (!root_tag_get(root, tag)) + return 0; + + if (height == 0) + return 1; + + shift = (height - 1) * RADIX_TREE_MAP_SHIFT; + slot = root->rnode; + + for ( ; ; ) { + int offset; + + if (slot == NULL) + return 0; + + offset = (index >> shift) & RADIX_TREE_MAP_MASK; + + /* + * This is just a debug check. Later, we can bale as soon as + * we see an unset tag. + */ + if (!tag_get(slot, tag, offset)) + saw_unset_tag = 1; + if (height == 1) { + int ret = tag_get(slot, tag, offset); + + BUG_ON(ret && saw_unset_tag); + return !!ret; + } + slot = slot->slots[offset]; + shift -= RADIX_TREE_MAP_SHIFT; + height--; + } +} +#endif + +static unsigned int +__lookup(struct radix_tree_root *root, void **results, unsigned long index, + unsigned int max_items, unsigned long *next_index) +{ + unsigned int nr_found = 0; + unsigned int shift, height; + struct radix_tree_node *slot; + unsigned long i; + + height = root->height; + if (height == 0) { + if (root->rnode && index == 0) + results[nr_found++] = root->rnode; + goto out; + } + + shift = (height-1) * RADIX_TREE_MAP_SHIFT; + slot = root->rnode; + + for ( ; height > 1; height--) { + + for (i = (index >> shift) & RADIX_TREE_MAP_MASK ; + i < RADIX_TREE_MAP_SIZE; i++) { + if (slot->slots[i] != NULL) + break; + index &= ~((1UL << shift) - 1); + index += 1UL << shift; + if (index == 0) + goto out; /* 32-bit wraparound */ + } + if (i == RADIX_TREE_MAP_SIZE) + goto out; + + shift -= RADIX_TREE_MAP_SHIFT; + slot = slot->slots[i]; + } + + /* Bottom level: grab some items */ + for (i = index & RADIX_TREE_MAP_MASK; i < RADIX_TREE_MAP_SIZE; i++) { + index++; + if (slot->slots[i]) { + results[nr_found++] = slot->slots[i]; + if (nr_found == max_items) + goto out; + } + } +out: + *next_index = index; + return nr_found; +} + +/** + * radix_tree_gang_lookup - perform multiple lookup on a radix tree + * @root: radix tree root + * @results: where the results of the lookup are placed + * @first_index: start the lookup from this key + * @max_items: place up to this many items at *results + * + * Performs an index-ascending scan of the tree for present items. Places + * them at *@results and returns the number of items which were placed at + * *@results. + * + * The implementation is naive. + */ +unsigned int +radix_tree_gang_lookup(struct radix_tree_root *root, void **results, + unsigned long first_index, unsigned int max_items) +{ + const unsigned long max_index = radix_tree_maxindex(root->height); + unsigned long cur_index = first_index; + unsigned int ret = 0; + + while (ret < max_items) { + unsigned int nr_found; + unsigned long next_index; /* Index of next search */ + + if (cur_index > max_index) + break; + nr_found = __lookup(root, results + ret, cur_index, + max_items - ret, &next_index); + ret += nr_found; + if (next_index == 0) + break; + cur_index = next_index; + } + return ret; +} + +/* + * FIXME: the two tag_get()s here should use find_next_bit() instead of + * open-coding the search. + */ +static unsigned int +__lookup_tag(struct radix_tree_root *root, void **results, unsigned long index, + unsigned int max_items, unsigned long *next_index, unsigned int tag) +{ + unsigned int nr_found = 0; + unsigned int shift; + unsigned int height = root->height; + struct radix_tree_node *slot; + + if (height == 0) { + if (root->rnode && index == 0) + results[nr_found++] = root->rnode; + goto out; + } + + shift = (height - 1) * RADIX_TREE_MAP_SHIFT; + slot = root->rnode; + + do { + unsigned long i = (index >> shift) & RADIX_TREE_MAP_MASK; + + for ( ; i < RADIX_TREE_MAP_SIZE; i++) { + if (tag_get(slot, tag, i)) { + BUG_ON(slot->slots[i] == NULL); + break; + } + index &= ~((1UL << shift) - 1); + index += 1UL << shift; + if (index == 0) + goto out; /* 32-bit wraparound */ + } + if (i == RADIX_TREE_MAP_SIZE) + goto out; + height--; + if (height == 0) { /* Bottom level: grab some items */ + unsigned long j = index & RADIX_TREE_MAP_MASK; + + for ( ; j < RADIX_TREE_MAP_SIZE; j++) { + index++; + if (tag_get(slot, tag, j)) { + BUG_ON(slot->slots[j] == NULL); + results[nr_found++] = slot->slots[j]; + if (nr_found == max_items) + goto out; + } + } + } + shift -= RADIX_TREE_MAP_SHIFT; + slot = slot->slots[i]; + } while (height > 0); +out: + *next_index = index; + return nr_found; +} + +/** + * radix_tree_gang_lookup_tag - perform multiple lookup on a radix tree + * based on a tag + * @root: radix tree root + * @results: where the results of the lookup are placed + * @first_index: start the lookup from this key + * @max_items: place up to this many items at *results + * @tag: the tag index (< RADIX_TREE_MAX_TAGS) + * + * Performs an index-ascending scan of the tree for present items which + * have the tag indexed by @tag set. Places the items at *@results and + * returns the number of items which were placed at *@results. + */ +unsigned int +radix_tree_gang_lookup_tag(struct radix_tree_root *root, void **results, + unsigned long first_index, unsigned int max_items, + unsigned int tag) +{ + const unsigned long max_index = radix_tree_maxindex(root->height); + unsigned long cur_index = first_index; + unsigned int ret = 0; + + /* check the root's tag bit */ + if (!root_tag_get(root, tag)) + return 0; + + while (ret < max_items) { + unsigned int nr_found; + unsigned long next_index; /* Index of next search */ + + if (cur_index > max_index) + break; + nr_found = __lookup_tag(root, results + ret, cur_index, + max_items - ret, &next_index, tag); + ret += nr_found; + if (next_index == 0) + break; + cur_index = next_index; + } + return ret; +} + +/** + * radix_tree_shrink - shrink height of a radix tree to minimal + * @root radix tree root + */ +static inline void radix_tree_shrink(struct radix_tree_root *root) +{ + /* try to shrink tree height */ + while (root->height > 0 && + root->rnode->count == 1 && + root->rnode->slots[0]) { + struct radix_tree_node *to_free = root->rnode; + + root->rnode = to_free->slots[0]; + root->height--; + /* must only free zeroed nodes into the slab */ + tag_clear(to_free, 0, 0); + tag_clear(to_free, 1, 0); + to_free->slots[0] = NULL; + to_free->count = 0; + radix_tree_node_free(to_free); + } +} + +/** + * radix_tree_delete - delete an item from a radix tree + * @root: radix tree root + * @index: index key + * + * Remove the item at @index from the radix tree rooted at @root. + * + * Returns the address of the deleted item, or NULL if it was not present. + */ +void *radix_tree_delete(struct radix_tree_root *root, unsigned long index) +{ + struct radix_tree_path path[RADIX_TREE_MAX_PATH], *pathp = path; + struct radix_tree_node *slot = NULL; + unsigned int height, shift; + int tag; + int offset; + + height = root->height; + if (index > radix_tree_maxindex(height)) + goto out; + + slot = root->rnode; + if (height == 0 && root->rnode) { + root_tag_clear_all(root); + root->rnode = NULL; + goto out; + } + + shift = (height - 1) * RADIX_TREE_MAP_SHIFT; + pathp->node = NULL; + + do { + if (slot == NULL) + goto out; + + pathp++; + offset = (index >> shift) & RADIX_TREE_MAP_MASK; + pathp->offset = offset; + pathp->node = slot; + slot = slot->slots[offset]; + shift -= RADIX_TREE_MAP_SHIFT; + height--; + } while (height > 0); + + if (slot == NULL) + goto out; + + /* + * Clear all tags associated with the just-deleted item + */ + for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) { + if (tag_get(pathp->node, tag, pathp->offset)) + radix_tree_tag_clear(root, index, tag); + } + + /* Now free the nodes we do not need anymore */ + while (pathp->node) { + pathp->node->slots[pathp->offset] = NULL; + pathp->node->count--; + + if (pathp->node->count) { + if (pathp->node == root->rnode) + radix_tree_shrink(root); + goto out; + } + + /* Node with zero slots in use so free it */ + radix_tree_node_free(pathp->node); + + pathp--; + } + root_tag_clear_all(root); + root->height = 0; + root->rnode = NULL; + +out: + return slot; +} + +/** + * radix_tree_tagged - test whether any items in the tree are tagged + * @root: radix tree root + * @tag: tag to test + */ +int radix_tree_tagged(struct radix_tree_root *root, unsigned int tag) +{ + return root_tag_get(root, tag); +} + +static unsigned long __maxindex(unsigned int height) +{ + unsigned int tmp = height * RADIX_TREE_MAP_SHIFT; + unsigned long index = ~0UL; + + if (tmp < RADIX_TREE_INDEX_BITS) + index = (index >> (RADIX_TREE_INDEX_BITS - tmp - 1)) >> 1; + return index; +} + +static void radix_tree_init_maxindex(void) +{ + unsigned int i; + + for (i = 0; i < ARRAY_SIZE(height_to_maxindex); i++) + height_to_maxindex[i] = __maxindex(i); +} + +void radix_tree_init(void) +{ + radix_tree_init_maxindex(); +} -- cgit v1.2.3