fs: btrfs: Add single-device read-only BTRFS implementation
This adds the proper implementation for the BTRFS filesystem.
The implementation currently supports only read-only mode and
the filesystem can be only on a single device.
Checksums of data chunks is unimplemented.
Compression is implemented (ZLIB + LZO).
Signed-off-by: Marek Behun <marek.behun@nic.cz>
create mode 100644 fs/btrfs/btrfs.h
create mode 100644 fs/btrfs/chunk-map.c
create mode 100644 fs/btrfs/compression.c
create mode 100644 fs/btrfs/ctree.c
create mode 100644 fs/btrfs/dev.c
create mode 100644 fs/btrfs/dir-item.c
create mode 100644 fs/btrfs/extent-io.c
create mode 100644 fs/btrfs/hash.c
create mode 100644 fs/btrfs/inode.c
create mode 100644 fs/btrfs/root.c
create mode 100644 fs/btrfs/subvolume.c
create mode 100644 fs/btrfs/super.c
diff --git a/fs/btrfs/dir-item.c b/fs/btrfs/dir-item.c
new file mode 100644
index 0000000..decf86e
--- /dev/null
+++ b/fs/btrfs/dir-item.c
@@ -0,0 +1,125 @@
+/*
+ * BTRFS filesystem implementation for U-Boot
+ *
+ * 2017 Marek Behun, CZ.NIC, marek.behun@nic.cz
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+
+#include "btrfs.h"
+
+static int verify_dir_item(struct btrfs_dir_item *item, u32 start, u32 total)
+{
+ u16 max_len = BTRFS_NAME_LEN;
+ u32 end;
+
+ if (item->type >= BTRFS_FT_MAX) {
+ printf("%s: invalid dir item type: %i\n", __func__, item->type);
+ return 1;
+ }
+
+ if (item->type == BTRFS_FT_XATTR)
+ max_len = 255; /* XATTR_NAME_MAX */
+
+ end = start + sizeof(*item) + item->name_len;
+ if (item->name_len > max_len || end > total) {
+ printf("%s: invalid dir item name len: %u\n", __func__,
+ item->name_len);
+ return 1;
+ }
+
+ return 0;
+}
+
+static struct btrfs_dir_item *
+btrfs_match_dir_item_name(struct btrfs_path *path, const char *name,
+ int name_len)
+{
+ struct btrfs_dir_item *item;
+ u32 total_len, cur = 0, this_len;
+ const char *name_ptr;
+
+ item = btrfs_path_item_ptr(path, struct btrfs_dir_item);
+
+ total_len = btrfs_path_item_size(path);
+
+ while (cur < total_len) {
+ btrfs_dir_item_to_cpu(item);
+ this_len = sizeof(*item) + item->name_len + item->data_len;
+ name_ptr = (const char *) (item + 1);
+
+ if (verify_dir_item(item, cur, total_len))
+ return NULL;
+ if (item->name_len == name_len && !memcmp(name_ptr, name,
+ name_len))
+ return item;
+
+ cur += this_len;
+ item = (struct btrfs_dir_item *) ((u8 *) item + this_len);
+ }
+
+ return NULL;
+}
+
+int btrfs_lookup_dir_item(const struct btrfs_root *root, u64 dir,
+ const char *name, int name_len,
+ struct btrfs_dir_item *item)
+{
+ struct btrfs_path path;
+ struct btrfs_key key;
+ struct btrfs_dir_item *res = NULL;
+
+ key.objectid = dir;
+ key.type = BTRFS_DIR_ITEM_KEY;
+ key.offset = btrfs_name_hash(name, name_len);
+
+ if (btrfs_search_tree(root, &key, &path))
+ return -1;
+
+ if (btrfs_comp_keys_type(&key, btrfs_path_leaf_key(&path)))
+ goto out;
+
+ res = btrfs_match_dir_item_name(&path, name, name_len);
+ if (res)
+ *item = *res;
+out:
+ btrfs_free_path(&path);
+ return res ? 0 : -1;
+}
+
+int btrfs_readdir(const struct btrfs_root *root, u64 dir,
+ btrfs_readdir_callback_t callback)
+{
+ struct btrfs_path path;
+ struct btrfs_key key, *found_key;
+ struct btrfs_dir_item *item;
+ int res;
+
+ key.objectid = dir;
+ key.type = BTRFS_DIR_INDEX_KEY;
+ key.offset = 0;
+
+ if (btrfs_search_tree(root, &key, &path))
+ return -1;
+
+ do {
+ found_key = btrfs_path_leaf_key(&path);
+ if (btrfs_comp_keys_type(&key, found_key))
+ break;
+
+ item = btrfs_path_item_ptr(&path, struct btrfs_dir_item);
+ btrfs_dir_item_to_cpu(item);
+
+ if (verify_dir_item(item, 0, sizeof(*item) + item->name_len))
+ continue;
+ if (item->type == BTRFS_FT_XATTR)
+ continue;
+
+ if (callback(root, item))
+ break;
+ } while (!(res = btrfs_next_slot(&path)));
+
+ btrfs_free_path(&path);
+
+ return res < 0 ? -1 : 0;
+}