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fs/btrfs/ctree.c
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d41ce506b Initial Release, ... |
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/* * BTRFS filesystem implementation for U-Boot * * 2017 Marek Behun, CZ.NIC, marek.behun@nic.cz * * SPDX-License-Identifier: GPL-2.0+ */ #include "btrfs.h" #include <malloc.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; if (0) { int i; printf("\tsearching %llu %i ", key->objectid, key->type); for (i = 0; i < max; ++i) { tmp = (struct btrfs_key *) ((u8 *) addr + i*item_size); printf("\t\t%llu %i ", tmp->objectid, tmp->type); } printf(" "); } 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) { struct btrfs_header hdr; 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(size); if (!res) { debug("%s: malloc failed ", __func__); return -1; } if (!btrfs_devread(physical + offset, size - offset, ((u8 *) res) + offset)) { free(res); return -1; } res->header = 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 ", __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 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] >= leaf->header.nritems) return jump_leaf(p, 1); p->slots[0]++; return 0; } |