GK SDK 源码库: XMIPCLinuxV100R005C00SPC030 (kernel/tools/open_source excluded)

source/bootloader/u-boot-2020.01/fs/btrfs/ctree.c

@@ -0,0 +1,290 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * BTRFS filesystem implementation for U-Boot
+ *
+ * 2017 Marek Behun, CZ.NIC, marek.behun@nic.cz
+ */
+
+#include "btrfs.h"
+#include <malloc.h>
+#include <memalign.h>
+
+int btrfs_comp_keys(struct btrfs_key *a, struct btrfs_key *b)
+{
+	if (a->objectid > b->objectid)
+		return 1;
+	if (a->objectid < b->objectid)
+		return -1;
+	if (a->type > b->type)
+		return 1;
+	if (a->type < b->type)
+		return -1;
+	if (a->offset > b->offset)
+		return 1;
+	if (a->offset < b->offset)
+		return -1;
+	return 0;
+}
+
+int btrfs_comp_keys_type(struct btrfs_key *a, struct btrfs_key *b)
+{
+	if (a->objectid > b->objectid)
+		return 1;
+	if (a->objectid < b->objectid)
+		return -1;
+	if (a->type > b->type)
+		return 1;
+	if (a->type < b->type)
+		return -1;
+	return 0;
+}
+
+static int generic_bin_search(void *addr, int item_size, struct btrfs_key *key,
+			      int max, int *slot)
+{
+	int low = 0, high = max, mid, ret;
+	struct btrfs_key *tmp;
+
+	while (low < high) {
+		mid = (low + high) / 2;
+
+		tmp = (struct btrfs_key *) ((u8 *) addr + mid*item_size);
+		ret = btrfs_comp_keys(tmp, key);
+
+		if (ret < 0) {
+			low = mid + 1;
+		} else if (ret > 0) {
+			high = mid;
+		} else {
+			*slot = mid;
+			return 0;
+		}
+	}
+
+	*slot = low;
+	return 1;
+}
+
+int btrfs_bin_search(union btrfs_tree_node *p, struct btrfs_key *key,
+		     int *slot)
+{
+	void *addr;
+	unsigned long size;
+
+	if (p->header.level) {
+		addr = p->node.ptrs;
+		size = sizeof(struct btrfs_key_ptr);
+	} else {
+		addr = p->leaf.items;
+		size = sizeof(struct btrfs_item);
+	}
+
+	return generic_bin_search(addr, size, key, p->header.nritems, slot);
+}
+
+static void clear_path(struct btrfs_path *p)
+{
+	int i;
+
+	for (i = 0; i < BTRFS_MAX_LEVEL; ++i) {
+		p->nodes[i] = NULL;
+		p->slots[i] = 0;
+	}
+}
+
+void btrfs_free_path(struct btrfs_path *p)
+{
+	int i;
+
+	for (i = 0; i < BTRFS_MAX_LEVEL; ++i) {
+		if (p->nodes[i])
+			free(p->nodes[i]);
+	}
+
+	clear_path(p);
+}
+
+static int read_tree_node(u64 physical, union btrfs_tree_node **buf)
+{
+	ALLOC_CACHE_ALIGN_BUFFER(struct btrfs_header, hdr,
+				 sizeof(struct btrfs_header));
+	unsigned long size, offset = sizeof(*hdr);
+	union btrfs_tree_node *res;
+	u32 i;
+
+	if (!btrfs_devread(physical, sizeof(*hdr), hdr))
+		return -1;
+
+	btrfs_header_to_cpu(hdr);
+
+	if (hdr->level)
+		size = sizeof(struct btrfs_node)
+		       + hdr->nritems * sizeof(struct btrfs_key_ptr);
+	else
+		size = btrfs_info.sb.nodesize;
+
+	res = malloc_cache_aligned(size);
+	if (!res) {
+		debug("%s: malloc failed\n", __func__);
+		return -1;
+	}
+
+	if (!btrfs_devread(physical + offset, size - offset,
+			   ((u8 *) res) + offset)) {
+		free(res);
+		return -1;
+	}
+
+	memcpy(&res->header, hdr, sizeof(*hdr));
+	if (hdr->level)
+		for (i = 0; i < hdr->nritems; ++i)
+			btrfs_key_ptr_to_cpu(&res->node.ptrs[i]);
+	else
+		for (i = 0; i < hdr->nritems; ++i)
+			btrfs_item_to_cpu(&res->leaf.items[i]);
+
+	*buf = res;
+
+	return 0;
+}
+
+int btrfs_search_tree(const struct btrfs_root *root, struct btrfs_key *key,
+		      struct btrfs_path *p)
+{
+	u8 lvl, prev_lvl;
+	int i, slot, ret;
+	u64 logical, physical;
+	union btrfs_tree_node *buf;
+
+	clear_path(p);
+
+	logical = root->bytenr;
+
+	for (i = 0; i < BTRFS_MAX_LEVEL; ++i) {
+		physical = btrfs_map_logical_to_physical(logical);
+		if (physical == -1ULL)
+			goto err;
+
+		if (read_tree_node(physical, &buf))
+			goto err;
+
+		lvl = buf->header.level;
+		if (i && prev_lvl != lvl + 1) {
+			printf("%s: invalid level in header at %llu\n",
+			       __func__, logical);
+			goto err;
+		}
+		prev_lvl = lvl;
+
+		ret = btrfs_bin_search(buf, key, &slot);
+		if (ret < 0)
+			goto err;
+		if (ret && slot > 0 && lvl)
+			slot -= 1;
+
+		p->slots[lvl] = slot;
+		p->nodes[lvl] = buf;
+
+		if (lvl) {
+			logical = buf->node.ptrs[slot].blockptr;
+		} else {
+			/*
+			 * The path might be invalid if:
+			 *   cur leaf max < searched value < next leaf min
+			 *
+			 * Jump to the next valid element if it exists.
+			 */
+			if (slot >= buf->header.nritems)
+				if (btrfs_next_slot(p) < 0)
+					goto err;
+			break;
+		}
+	}
+
+	return 0;
+err:
+	btrfs_free_path(p);
+	return -1;
+}
+
+static int jump_leaf(struct btrfs_path *path, int dir)
+{
+	struct btrfs_path p;
+	u32 slot;
+	int level = 1, from_level, i;
+
+	dir = dir >= 0 ? 1 : -1;
+
+	p = *path;
+
+	while (level < BTRFS_MAX_LEVEL) {
+		if (!p.nodes[level])
+			return 1;
+
+		slot = p.slots[level];
+		if ((dir > 0 && slot + dir >= p.nodes[level]->header.nritems)
+		    || (dir < 0 && !slot))
+			level++;
+		else
+			break;
+	}
+
+	if (level == BTRFS_MAX_LEVEL)
+		return 1;
+
+	p.slots[level] = slot + dir;
+	level--;
+	from_level = level;
+
+	while (level >= 0) {
+		u64 logical, physical;
+
+		slot = p.slots[level + 1];
+		logical = p.nodes[level + 1]->node.ptrs[slot].blockptr;
+		physical = btrfs_map_logical_to_physical(logical);
+		if (physical == -1ULL)
+			goto err;
+
+		if (read_tree_node(physical, &p.nodes[level]))
+			goto err;
+
+		if (dir > 0)
+			p.slots[level] = 0;
+		else
+			p.slots[level] = p.nodes[level]->header.nritems - 1;
+		level--;
+	}
+
+	/* Free rewritten nodes in path */
+	for (i = 0; i <= from_level; ++i)
+		free(path->nodes[i]);
+
+	*path = p;
+	return 0;
+
+err:
+	/* Free rewritten nodes in p */
+	for (i = level + 1; i <= from_level; ++i)
+		free(p.nodes[i]);
+	return -1;
+}
+
+int btrfs_prev_slot(struct btrfs_path *p)
+{
+	if (!p->slots[0])
+		return jump_leaf(p, -1);
+
+	p->slots[0]--;
+	return 0;
+}
+
+int btrfs_next_slot(struct btrfs_path *p)
+{
+	struct btrfs_leaf *leaf = &p->nodes[0]->leaf;
+
+	if (p->slots[0] + 1 >= leaf->header.nritems)
+		return jump_leaf(p, 1);
+
+	p->slots[0]++;
+	return 0;
+}