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

1 files changed, 89 insertions, 0 deletions

diff --git a/fs/btrfs/btrfs.h b/fs/btrfs/btrfs.h
new file mode 100644
index 00000000000..4247cbbb097
--- /dev/null
+++ b/fs/btrfs/btrfs.h
@@ -0,0 +1,89 @@
+/*
+ * BTRFS filesystem implementation for U-Boot
+ *
+ * 2017 Marek Behun, CZ.NIC, marek.behun@nic.cz
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#ifndef __BTRFS_BTRFS_H__
+#define __BTRFS_BTRFS_H__
+
+#include <linux/rbtree.h>
+#include "conv-funcs.h"
+
+struct btrfs_info {
+	struct btrfs_super_block sb;
+	struct btrfs_root_backup *root_backup;
+
+	struct btrfs_root tree_root;
+	struct btrfs_root fs_root;
+	struct btrfs_root chunk_root;
+
+	struct rb_root chunks_root;
+};
+
+extern struct btrfs_info btrfs_info;
+
+/* hash.c */
+void btrfs_hash_init(void);
+u32 btrfs_crc32c(u32, const void *, size_t);
+u32 btrfs_csum_data(char *, u32, size_t);
+void btrfs_csum_final(u32, void *);
+
+static inline u64 btrfs_name_hash(const char *name, int len)
+{
+	return btrfs_crc32c((u32) ~1, name, len);
+}
+
+/* dev.c */
+extern struct blk_desc *btrfs_blk_desc;
+extern disk_partition_t *btrfs_part_info;
+
+int btrfs_devread(u64, int, void *);
+
+/* chunk-map.c */
+u64 btrfs_map_logical_to_physical(u64);
+int btrfs_chunk_map_init(void);
+void btrfs_chunk_map_exit(void);
+int btrfs_read_chunk_tree(void);
+
+/* compression.c */
+u32 btrfs_decompress(u8 type, const char *, u32, char *, u32);
+
+/* super.c */
+int btrfs_read_superblock(void);
+
+/* dir-item.c */
+typedef int (*btrfs_readdir_callback_t)(const struct btrfs_root *,
+					struct btrfs_dir_item *);
+
+int btrfs_lookup_dir_item(const struct btrfs_root *, u64, const char *, int,
+			   struct btrfs_dir_item *);
+int btrfs_readdir(const struct btrfs_root *, u64, btrfs_readdir_callback_t);
+
+/* root.c */
+int btrfs_find_root(u64, struct btrfs_root *, struct btrfs_root_item *);
+u64 btrfs_lookup_root_ref(u64, struct btrfs_root_ref *, char *);
+
+/* inode.c */
+u64 btrfs_lookup_inode_ref(struct btrfs_root *, u64, struct btrfs_inode_ref *,
+			    char *);
+int btrfs_lookup_inode(const struct btrfs_root *, struct btrfs_key *,
+		        struct btrfs_inode_item *, struct btrfs_root *);
+int btrfs_readlink(const struct btrfs_root *, u64, char *);
+u64 btrfs_lookup_path(struct btrfs_root *, u64, const char *, u8 *,
+		       struct btrfs_inode_item *, int);
+u64 btrfs_file_read(const struct btrfs_root *, u64, u64, u64, char *);
+
+/* subvolume.c */
+u64 btrfs_get_default_subvol_objectid(void);
+
+/* extent-io.c */
+u64 btrfs_read_extent_inline(struct btrfs_path *,
+			      struct btrfs_file_extent_item *, u64, u64,
+			      char *);
+u64 btrfs_read_extent_reg(struct btrfs_path *, struct btrfs_file_extent_item *,
+			   u64, u64, char *);
+
+#endif /* !__BTRFS_BTRFS_H__ */