385 lines
7.9 KiB
C
385 lines
7.9 KiB
C
/*
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* BTRFS filesystem implementation for U-Boot
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*
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* 2017 Marek Behun, CZ.NIC, marek.behun@nic.cz
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*
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* SPDX-License-Identifier: GPL-2.0+
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*/
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#include "btrfs.h"
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#include <malloc.h>
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u64 btrfs_lookup_inode_ref(struct btrfs_root *root, u64 inr,
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struct btrfs_inode_ref *refp, char *name)
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{
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struct btrfs_path path;
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struct btrfs_key *key;
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struct btrfs_inode_ref *ref;
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u64 res = -1ULL;
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key = btrfs_search_tree_key_type(root, inr, BTRFS_INODE_REF_KEY,
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&path);
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if (!key)
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return -1ULL;
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ref = btrfs_path_item_ptr(&path, struct btrfs_inode_ref);
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btrfs_inode_ref_to_cpu(ref);
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if (refp)
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*refp = *ref;
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if (name) {
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if (ref->name_len > BTRFS_NAME_MAX) {
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printf("%s: inode name too long: %u\n", __func__,
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ref->name_len);
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goto out;
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}
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memcpy(name, ref + 1, ref->name_len);
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}
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res = key->offset;
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out:
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btrfs_free_path(&path);
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return res;
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}
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int btrfs_lookup_inode(const struct btrfs_root *root,
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struct btrfs_key *location,
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struct btrfs_inode_item *item,
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struct btrfs_root *new_root)
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{
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struct btrfs_root tmp_root = *root;
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struct btrfs_path path;
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int res = -1;
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if (location->type == BTRFS_ROOT_ITEM_KEY) {
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if (btrfs_find_root(location->objectid, &tmp_root, NULL))
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return -1;
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location->objectid = tmp_root.root_dirid;
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location->type = BTRFS_INODE_ITEM_KEY;
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location->offset = 0;
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}
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if (btrfs_search_tree(&tmp_root, location, &path))
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return res;
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if (btrfs_comp_keys(location, btrfs_path_leaf_key(&path)))
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goto out;
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if (item) {
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*item = *btrfs_path_item_ptr(&path, struct btrfs_inode_item);
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btrfs_inode_item_to_cpu(item);
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}
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if (new_root)
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*new_root = tmp_root;
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res = 0;
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out:
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btrfs_free_path(&path);
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return res;
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}
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int btrfs_readlink(const struct btrfs_root *root, u64 inr, char *target)
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{
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struct btrfs_path path;
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struct btrfs_key key;
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struct btrfs_file_extent_item *extent;
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const char *data_ptr;
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int res = -1;
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key.objectid = inr;
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key.type = BTRFS_EXTENT_DATA_KEY;
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key.offset = 0;
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if (btrfs_search_tree(root, &key, &path))
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return -1;
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if (btrfs_comp_keys(&key, btrfs_path_leaf_key(&path)))
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goto out;
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extent = btrfs_path_item_ptr(&path, struct btrfs_file_extent_item);
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if (extent->type != BTRFS_FILE_EXTENT_INLINE) {
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printf("%s: Extent for symlink %llu not of INLINE type\n",
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__func__, inr);
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goto out;
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}
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btrfs_file_extent_item_to_cpu_inl(extent);
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if (extent->compression != BTRFS_COMPRESS_NONE) {
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printf("%s: Symlink %llu extent data compressed!\n", __func__,
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inr);
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goto out;
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} else if (extent->encryption != 0) {
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printf("%s: Symlink %llu extent data encrypted!\n", __func__,
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inr);
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goto out;
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} else if (extent->ram_bytes >= btrfs_info.sb.sectorsize) {
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printf("%s: Symlink %llu extent data too long (%llu)!\n",
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__func__, inr, extent->ram_bytes);
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goto out;
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}
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data_ptr = (const char *) extent
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+ offsetof(struct btrfs_file_extent_item, disk_bytenr);
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memcpy(target, data_ptr, extent->ram_bytes);
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target[extent->ram_bytes] = '\0';
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res = 0;
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out:
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btrfs_free_path(&path);
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return res;
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}
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/* inr must be a directory (for regular files with multiple hard links this
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function returns only one of the parents of the file) */
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static u64 get_parent_inode(struct btrfs_root *root, u64 inr,
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struct btrfs_inode_item *inode_item)
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{
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struct btrfs_key key;
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u64 res;
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if (inr == BTRFS_FIRST_FREE_OBJECTID) {
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if (root->objectid != btrfs_info.fs_root.objectid) {
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u64 parent;
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struct btrfs_root_ref ref;
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parent = btrfs_lookup_root_ref(root->objectid, &ref,
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NULL);
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if (parent == -1ULL)
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return -1ULL;
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if (btrfs_find_root(parent, root, NULL))
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return -1ULL;
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inr = ref.dirid;
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}
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if (inode_item) {
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key.objectid = inr;
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key.type = BTRFS_INODE_ITEM_KEY;
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key.offset = 0;
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if (btrfs_lookup_inode(root, &key, inode_item, NULL))
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return -1ULL;
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}
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return inr;
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}
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res = btrfs_lookup_inode_ref(root, inr, NULL, NULL);
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if (res == -1ULL)
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return -1ULL;
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if (inode_item) {
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key.objectid = res;
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key.type = BTRFS_INODE_ITEM_KEY;
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key.offset = 0;
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if (btrfs_lookup_inode(root, &key, inode_item, NULL))
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return -1ULL;
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}
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return res;
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}
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static inline int next_length(const char *path)
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{
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int res = 0;
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while (*path != '\0' && *path != '/' && res <= BTRFS_NAME_LEN)
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++res, ++path;
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return res;
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}
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static inline const char *skip_current_directories(const char *cur)
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{
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while (1) {
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if (cur[0] == '/')
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++cur;
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else if (cur[0] == '.' && cur[1] == '/')
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cur += 2;
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else
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break;
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}
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return cur;
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}
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u64 btrfs_lookup_path(struct btrfs_root *root, u64 inr, const char *path,
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u8 *type_p, struct btrfs_inode_item *inode_item_p,
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int symlink_limit)
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{
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struct btrfs_dir_item item;
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struct btrfs_inode_item inode_item;
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u8 type = BTRFS_FT_DIR;
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int len, have_inode = 0;
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const char *cur = path;
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if (*cur == '/') {
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++cur;
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inr = root->root_dirid;
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}
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do {
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cur = skip_current_directories(cur);
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len = next_length(cur);
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if (len > BTRFS_NAME_LEN) {
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printf("%s: Name too long at \"%.*s\"\n", __func__,
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BTRFS_NAME_LEN, cur);
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return -1ULL;
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}
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if (len == 1 && cur[0] == '.')
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break;
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if (len == 2 && cur[0] == '.' && cur[1] == '.') {
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cur += 2;
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inr = get_parent_inode(root, inr, &inode_item);
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if (inr == -1ULL)
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return -1ULL;
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type = BTRFS_FT_DIR;
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continue;
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}
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if (!*cur)
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break;
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if (btrfs_lookup_dir_item(root, inr, cur, len, &item))
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return -1ULL;
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type = item.type;
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have_inode = 1;
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if (btrfs_lookup_inode(root, &item.location, &inode_item, root))
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return -1ULL;
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if (item.type == BTRFS_FT_SYMLINK && symlink_limit >= 0) {
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char *target;
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if (!symlink_limit) {
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printf("%s: Too much symlinks!\n", __func__);
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return -1ULL;
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}
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target = malloc(min(inode_item.size + 1,
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(u64) btrfs_info.sb.sectorsize));
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if (!target)
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return -1ULL;
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if (btrfs_readlink(root, item.location.objectid,
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target)) {
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free(target);
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return -1ULL;
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}
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inr = btrfs_lookup_path(root, inr, target, &type,
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&inode_item, symlink_limit - 1);
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free(target);
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if (inr == -1ULL)
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return -1ULL;
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} else if (item.type != BTRFS_FT_DIR && cur[len]) {
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printf("%s: \"%.*s\" not a directory\n", __func__,
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(int) (cur - path + len), path);
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return -1ULL;
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} else {
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inr = item.location.objectid;
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}
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cur += len;
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} while (*cur);
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if (type_p)
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*type_p = type;
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if (inode_item_p) {
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if (!have_inode) {
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struct btrfs_key key;
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key.objectid = inr;
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key.type = BTRFS_INODE_ITEM_KEY;
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key.offset = 0;
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if (btrfs_lookup_inode(root, &key, &inode_item, NULL))
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return -1ULL;
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}
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*inode_item_p = inode_item;
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}
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return inr;
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}
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u64 btrfs_file_read(const struct btrfs_root *root, u64 inr, u64 offset,
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u64 size, char *buf)
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{
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struct btrfs_path path;
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struct btrfs_key key;
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struct btrfs_file_extent_item *extent;
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int res = 0;
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u64 rd, rd_all = -1ULL;
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key.objectid = inr;
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key.type = BTRFS_EXTENT_DATA_KEY;
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key.offset = offset;
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if (btrfs_search_tree(root, &key, &path))
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return -1ULL;
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if (btrfs_comp_keys(&key, btrfs_path_leaf_key(&path)) < 0) {
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if (btrfs_prev_slot(&path))
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goto out;
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if (btrfs_comp_keys_type(&key, btrfs_path_leaf_key(&path)))
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goto out;
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}
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rd_all = 0;
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do {
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if (btrfs_comp_keys_type(&key, btrfs_path_leaf_key(&path)))
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break;
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extent = btrfs_path_item_ptr(&path,
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struct btrfs_file_extent_item);
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if (extent->type == BTRFS_FILE_EXTENT_INLINE) {
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btrfs_file_extent_item_to_cpu_inl(extent);
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rd = btrfs_read_extent_inline(&path, extent, offset,
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size, buf);
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} else {
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btrfs_file_extent_item_to_cpu(extent);
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rd = btrfs_read_extent_reg(&path, extent, offset, size,
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buf);
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}
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if (rd == -1ULL) {
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printf("%s: Error reading extent\n", __func__);
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rd_all = -1;
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goto out;
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}
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offset = 0;
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buf += rd;
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rd_all += rd;
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size -= rd;
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if (!size)
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break;
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} while (!(res = btrfs_next_slot(&path)));
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if (res)
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return -1ULL;
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out:
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btrfs_free_path(&path);
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return rd_all;
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}
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