94 lines
1.9 KiB
C
94 lines
1.9 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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static void read_root_item(struct btrfs_path *p, struct btrfs_root_item *item)
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{
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u32 len;
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int reset = 0;
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len = btrfs_path_item_size(p);
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memcpy(item, btrfs_path_item_ptr(p, struct btrfs_root_item), len);
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btrfs_root_item_to_cpu(item);
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if (len < sizeof(*item))
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reset = 1;
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if (!reset && item->generation != item->generation_v2) {
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if (item->generation_v2 != 0)
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printf("%s: generation != generation_v2 in root item",
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__func__);
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reset = 1;
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}
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if (reset) {
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memset(&item->generation_v2, 0,
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sizeof(*item) - offsetof(struct btrfs_root_item,
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generation_v2));
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}
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}
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int btrfs_find_root(u64 objectid, struct btrfs_root *root,
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struct btrfs_root_item *root_item)
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{
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struct btrfs_path path;
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struct btrfs_root_item my_root_item;
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if (!btrfs_search_tree_key_type(&btrfs_info.tree_root, objectid,
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BTRFS_ROOT_ITEM_KEY, &path))
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return -1;
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if (!root_item)
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root_item = &my_root_item;
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read_root_item(&path, root_item);
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if (root) {
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root->objectid = objectid;
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root->bytenr = root_item->bytenr;
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root->root_dirid = root_item->root_dirid;
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}
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btrfs_free_path(&path);
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return 0;
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}
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u64 btrfs_lookup_root_ref(u64 subvolid, struct btrfs_root_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_root_ref *ref;
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u64 res = -1ULL;
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key = btrfs_search_tree_key_type(&btrfs_info.tree_root, subvolid,
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BTRFS_ROOT_BACKREF_KEY, &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_root_ref);
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btrfs_root_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_VOL_NAME_MAX) {
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printf("%s: volume 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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