mirror of
https://github.com/versity/scoutfs.git
synced 2026-04-22 14:30:31 +00:00
cf278f5fa0
Prefer named to anonymous enums. This helps readability a little. Use enum as param type if possible (a couple spots). Remove unused enum in lock_server.c. Define enum spbm_flags using shift notation for consistency. Rename get_file_block()'s "gfb" parameter to "flags" for consistency. Signed-off-by: Andy Grover <agrover@versity.com>
159 lines
3.2 KiB
C
159 lines
3.2 KiB
C
/*
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* Copyright (C) 2018 Versity Software, Inc. All rights reserved.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public
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* License v2 as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*/
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#include <linux/kernel.h>
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#include <linux/slab.h>
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#include <linux/log2.h>
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#include <linux/bitmap.h>
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#include <linux/rbtree.h>
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#include "spbm.h"
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#define SPBM_BITS 128
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#define SPBM_SHIFT ilog2(SPBM_BITS)
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#define SPBM_MASK ((u64)SPBM_BITS - 1)
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#define SPBM_LONGS (SPBM_BITS / BITS_PER_LONG)
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/*
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* Maintain a sparse bitmap in an rbtree. Setting bits can allocate and
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* fail but clearing will always succeed. Locking is left up to the
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* caller.
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*/
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struct spbm_node {
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struct rb_node node;
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u64 index;
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unsigned long bits[SPBM_LONGS];
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};
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void scoutfs_spbm_init(struct scoutfs_spbm *spbm)
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{
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BUILD_BUG_ON(!is_power_of_2(SPBM_BITS));
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spbm->root = RB_ROOT;
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}
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bool scoutfs_spbm_empty(struct scoutfs_spbm *spbm)
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{
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return RB_EMPTY_ROOT(&spbm->root);
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}
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enum spbm_flags {
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/* if a node isn't found then return an allocated new node */
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SPBM_FIND_ALLOC = (1 << 0),
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};
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static struct spbm_node *find_node(struct scoutfs_spbm *spbm, u64 index,
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int flags)
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{
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struct rb_node *parent;
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struct rb_node **node;
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struct spbm_node *sn;
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node = &spbm->root.rb_node;
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parent = NULL;
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sn = NULL;
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while (*node) {
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parent = *node;
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sn = container_of(*node, struct spbm_node, node);
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if (index < sn->index) {
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node = &(*node)->rb_left;
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} else if (index > sn->index) {
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node = &(*node)->rb_right;
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} else {
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break;
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}
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sn = NULL;
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}
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if (!sn && (flags & SPBM_FIND_ALLOC)) {
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sn = kzalloc(sizeof(struct spbm_node), GFP_NOFS);
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if (sn) {
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sn->index = index;
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rb_link_node(&sn->node, parent, node);
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rb_insert_color(&sn->node, &spbm->root);
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}
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}
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return sn;
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}
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static void calc_index_nr(u64 *index, int *nr, u64 bit)
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{
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*index = bit >> SPBM_SHIFT;
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*nr = bit & SPBM_MASK;
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}
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int scoutfs_spbm_set(struct scoutfs_spbm *spbm, u64 bit)
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{
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struct spbm_node *sn;
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u64 index;
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int nr;
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calc_index_nr(&index, &nr, bit);
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sn = find_node(spbm, index, SPBM_FIND_ALLOC);
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if (!sn)
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return -ENOMEM;
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set_bit(nr, sn->bits);
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return 0;
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}
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int scoutfs_spbm_test(struct scoutfs_spbm *spbm, u64 bit)
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{
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struct spbm_node *sn;
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u64 index;
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int nr;
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calc_index_nr(&index, &nr, bit);
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sn = find_node(spbm, index, 0);
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if (sn)
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return !!test_bit(nr, sn->bits);
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return 0;
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}
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static void free_node(struct scoutfs_spbm *spbm, struct spbm_node *sn)
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{
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rb_erase(&sn->node, &spbm->root);
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kfree(sn);
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}
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void scoutfs_spbm_clear(struct scoutfs_spbm *spbm, u64 bit)
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{
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struct spbm_node *sn;
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u64 index;
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int nr;
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calc_index_nr(&index, &nr, bit);
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sn = find_node(spbm, index, 0);
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if (sn) {
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clear_bit(nr, sn->bits);
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if (bitmap_empty(sn->bits, SPBM_BITS))
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free_node(spbm, sn);
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}
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}
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void scoutfs_spbm_destroy(struct scoutfs_spbm *spbm)
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{
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struct spbm_node *sn;
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struct spbm_node *pos;
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rbtree_postorder_for_each_entry_safe(sn, pos, &spbm->root, node)
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free_node(spbm, sn);
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}
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