fs: btrfs: Add U-Boot fs handlers.

Signed-off-by: Marek Behun <marek.behun@nic.cz>

 create mode 100644 fs/btrfs/Kconfig
 create mode 100644 fs/btrfs/Makefile
 create mode 100644 fs/btrfs/btrfs.c
 create mode 100644 include/btrfs.h

3 files changed, 244 insertions, 0 deletions

diff --git a/fs/btrfs/Kconfig b/fs/btrfs/Kconfig
new file mode 100644
index 0000000000..22909d9fcc
--- /dev/null
+++ b/fs/btrfs/Kconfig
@@ -0,0 +1,9 @@
+config FS_BTRFS
+	bool "Enable BTRFS filesystem support"
+	select CRC32C
+	select LZO
+	select RBTREE
+	help
+	  This provides a single-device read-only BTRFS support. BTRFS is a
+	  next-generation Linux file system based on the copy-on-write
+	  principle.
diff --git a/fs/btrfs/Makefile b/fs/btrfs/Makefile
new file mode 100644
index 0000000000..01731557e6
--- /dev/null
+++ b/fs/btrfs/Makefile
@@ -0,0 +1,8 @@
+#
+# 2017 Marek Behun, CZ.NIC, marek.behun@nic.cz
+#
+# SPDX-License-Identifier:	GPL-2.0+
+#
+
+obj-y := btrfs.o chunk-map.o compression.o ctree.o dev.o dir-item.o \
+	extent-io.o hash.o inode.o root.o subvolume.o super.o
diff --git a/fs/btrfs/btrfs.c b/fs/btrfs/btrfs.c
new file mode 100644
index 0000000000..4140e2bc20
--- /dev/null
+++ b/fs/btrfs/btrfs.c
@@ -0,0 +1,227 @@
+/*
+ * BTRFS filesystem implementation for U-Boot
+ *
+ * 2017 Marek Behun, CZ.NIC, marek.behun@nic.cz
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include "btrfs.h"
+#include <config.h>
+#include <malloc.h>
+#include <linux/time.h>
+
+struct btrfs_info btrfs_info;
+
+static int readdir_callback(const struct btrfs_root *root,
+			    struct btrfs_dir_item *item)
+{
+	static const char typestr[BTRFS_FT_MAX][4] = {
+		[BTRFS_FT_UNKNOWN]  = " ? ",
+		[BTRFS_FT_REG_FILE] = "   ",
+		[BTRFS_FT_DIR]      = "DIR",
+		[BTRFS_FT_CHRDEV]   = "CHR",
+		[BTRFS_FT_BLKDEV]   = "BLK",
+		[BTRFS_FT_FIFO]     = "FIF",
+		[BTRFS_FT_SOCK]     = "SCK",
+		[BTRFS_FT_SYMLINK]  = "SYM",
+		[BTRFS_FT_XATTR]    = " ? ",
+	};
+	struct btrfs_inode_item inode;
+	const char *name = (const char *) (item + 1);
+	char filetime[32], *target = NULL;
+	time_t mtime;
+
+	if (btrfs_lookup_inode(root, &item->location, &inode, NULL)) {
+		printf("%s: Cannot find inode item for directory entry %.*s!\n",
+		       __func__, item->name_len, name);
+		return 0;
+	}
+
+	mtime = inode.mtime.sec;
+	ctime_r(&mtime, filetime);
+
+	if (item->type == BTRFS_FT_SYMLINK) {
+		target = malloc(min(inode.size + 1,
+				    (u64) btrfs_info.sb.sectorsize));
+
+		if (target && btrfs_readlink(root, item->location.objectid,
+					     target)) {
+			free(target);
+			target = NULL;
+		}
+
+		if (!target)
+			printf("%s: Cannot read symlink target!\n", __func__);
+	}
+
+	printf("<%s> ", typestr[item->type]);
+	if (item->type == BTRFS_FT_CHRDEV || item->type == BTRFS_FT_BLKDEV)
+		printf("%4u,%5u  ", (unsigned int) (inode.rdev >> 20),
+			(unsigned int) (inode.rdev & 0xfffff));
+	else
+		printf("%10llu  ", inode.size);
+
+	printf("%24.24s  %.*s", filetime, item->name_len, name);
+
+	if (item->type == BTRFS_FT_SYMLINK) {
+		printf(" -> %s", target ? target : "?");
+		if (target)
+			free(target);
+	}
+
+	printf("\n");
+
+	return 0;
+}
+
+int btrfs_probe(struct blk_desc *fs_dev_desc, disk_partition_t *fs_partition)
+{
+	btrfs_blk_desc = fs_dev_desc;
+	btrfs_part_info = fs_partition;
+
+	memset(&btrfs_info, 0, sizeof(btrfs_info));
+
+	btrfs_hash_init();
+	if (btrfs_read_superblock())
+		return -1;
+
+	if (btrfs_chunk_map_init()) {
+		printf("%s: failed to init chunk map\n", __func__);
+		return -1;
+	}
+
+	btrfs_info.tree_root.objectid = 0;
+	btrfs_info.tree_root.bytenr = btrfs_info.sb.root;
+	btrfs_info.chunk_root.objectid = 0;
+	btrfs_info.chunk_root.bytenr = btrfs_info.sb.chunk_root;
+
+	if (btrfs_read_chunk_tree()) {
+		printf("%s: failed to read chunk tree\n", __func__);
+		return -1;
+	}
+
+	if (btrfs_find_root(btrfs_get_default_subvol_objectid(),
+			    &btrfs_info.fs_root, NULL)) {
+		printf("%s: failed to find default subvolume\n", __func__);
+		return -1;
+	}
+
+	return 0;
+}
+
+int btrfs_ls(const char *path)
+{
+	struct btrfs_root root = btrfs_info.fs_root;
+	u64 inr;
+	u8 type;
+
+	inr = btrfs_lookup_path(&root, root.root_dirid, path, &type, NULL, 40);
+
+	if (inr == -1ULL) {
+		printf("Cannot lookup path %s\n", path);
+		return 1;
+	}
+
+	if (type != BTRFS_FT_DIR) {
+		printf("Not a directory: %s\n", path);
+		return 1;
+	}
+
+	if (btrfs_readdir(&root, inr, readdir_callback)) {
+		printf("An error occured while listing directory %s\n", path);
+		return 1;
+	}
+
+	return 0;
+}
+
+int btrfs_exists(const char *file)
+{
+	struct btrfs_root root = btrfs_info.fs_root;
+	u64 inr;
+	u8 type;
+
+	inr = btrfs_lookup_path(&root, root.root_dirid, file, &type, NULL, 40);
+
+	return (inr != -1ULL && type == BTRFS_FT_REG_FILE);
+}
+
+int btrfs_size(const char *file, loff_t *size)
+{
+	struct btrfs_root root = btrfs_info.fs_root;
+	struct btrfs_inode_item inode;
+	u64 inr;
+	u8 type;
+
+	inr = btrfs_lookup_path(&root, root.root_dirid, file, &type, &inode,
+				40);
+
+	if (inr == -1ULL) {
+		printf("Cannot lookup file %s\n", file);
+		return 1;
+	}
+
+	if (type != BTRFS_FT_REG_FILE) {
+		printf("Not a regular file: %s\n", file);
+		return 1;
+	}
+
+	*size = inode.size;
+	return 0;
+}
+
+int btrfs_read(const char *file, void *buf, loff_t offset, loff_t len,
+	       loff_t *actread)
+{
+	struct btrfs_root root = btrfs_info.fs_root;
+	struct btrfs_inode_item inode;
+	u64 inr, rd;
+	u8 type;
+
+	inr = btrfs_lookup_path(&root, root.root_dirid, file, &type, &inode,
+				40);
+
+	if (inr == -1ULL) {
+		printf("Cannot lookup file %s\n", file);
+		return 1;
+	}
+
+	if (type != BTRFS_FT_REG_FILE) {
+		printf("Not a regular file: %s\n", file);
+		return 1;
+	}
+
+	if (!len)
+		len = inode.size;
+
+	if (len > inode.size - offset)
+		len = inode.size - offset;
+
+	rd = btrfs_file_read(&root, inr, offset, len, buf);
+	if (rd == -1ULL) {
+		printf("An error occured while reading file %s\n", file);
+		return 1;
+	}
+
+	*actread = rd;
+	return 0;
+}
+
+void btrfs_close(void)
+{
+	btrfs_chunk_map_exit();
+}
+
+int btrfs_uuid(char *uuid_str)
+{
+#ifdef CONFIG_LIB_UUID
+	uuid_bin_to_str(btrfs_info.sb.fsid, uuid_str, UUID_STR_FORMAT_STD);
+	return 0;
+#endif
+	return -ENOSYS;
+}
+
+/*
+		btrfs_list_subvols();
+*/