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/root.c b/fs/btrfs/root.c
new file mode 100644
index 0000000..c405813
--- /dev/null
+++ b/fs/btrfs/root.c
@@ -0,0 +1,93 @@
+/*
+ * 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 void read_root_item(struct btrfs_path *p, struct btrfs_root_item *item)
+{
+ u32 len;
+ int reset = 0;
+
+ len = btrfs_path_item_size(p);
+ memcpy(item, btrfs_path_item_ptr(p, struct btrfs_root_item), len);
+ btrfs_root_item_to_cpu(item);
+
+ if (len < sizeof(*item))
+ reset = 1;
+ if (!reset && item->generation != item->generation_v2) {
+ if (item->generation_v2 != 0)
+ printf("%s: generation != generation_v2 in root item",
+ __func__);
+ reset = 1;
+ }
+ if (reset) {
+ memset(&item->generation_v2, 0,
+ sizeof(*item) - offsetof(struct btrfs_root_item,
+ generation_v2));
+ }
+}
+
+int btrfs_find_root(u64 objectid, struct btrfs_root *root,
+ struct btrfs_root_item *root_item)
+{
+ struct btrfs_path path;
+ struct btrfs_root_item my_root_item;
+
+ if (!btrfs_search_tree_key_type(&btrfs_info.tree_root, objectid,
+ BTRFS_ROOT_ITEM_KEY, &path))
+ return -1;
+
+ if (!root_item)
+ root_item = &my_root_item;
+ read_root_item(&path, root_item);
+
+ if (root) {
+ root->objectid = objectid;
+ root->bytenr = root_item->bytenr;
+ root->root_dirid = root_item->root_dirid;
+ }
+
+ btrfs_free_path(&path);
+ return 0;
+}
+
+u64 btrfs_lookup_root_ref(u64 subvolid, struct btrfs_root_ref *refp, char *name)
+{
+ struct btrfs_path path;
+ struct btrfs_key *key;
+ struct btrfs_root_ref *ref;
+ u64 res = -1ULL;
+
+ key = btrfs_search_tree_key_type(&btrfs_info.tree_root, subvolid,
+ BTRFS_ROOT_BACKREF_KEY, &path);
+
+ if (!key)
+ return -1ULL;
+
+ ref = btrfs_path_item_ptr(&path, struct btrfs_root_ref);
+ btrfs_root_ref_to_cpu(ref);
+
+ if (refp)
+ *refp = *ref;
+
+ if (name) {
+ if (ref->name_len > BTRFS_VOL_NAME_MAX) {
+ printf("%s: volume name too long: %u\n", __func__,
+ ref->name_len);
+ goto out;
+ }
+
+ memcpy(name, ref + 1, ref->name_len);
+ }
+
+ res = key->offset;
+out:
+ btrfs_free_path(&path);
+ return res;
+}
+