Introduces btrfs file-system to read file from
volume/sub-volumes with btrload command. This
implementation has read-only support.
This btrfs implementation is based on syslinux btrfs
code, commit 269ebc845ebc8b46ef4b0be7fa0005c7fdb95b8d.

v11:     Mirro super block check.
v10:     patch problem reworked.
v5:      merged with master.
v4:      btrls command added.

Signed-off-by: Adnan Ali <adnan....@codethink.co.uk>
---
 Makefile                   |    1 +
 common/Makefile            |    1 +
 common/cmd_btr.c           |   65 +++
 fs/btrfs/Makefile          |   51 ++
 fs/btrfs/btrfs.c           | 1344 ++++++++++++++++++++++++++++++++++++++++++++
 fs/fs.c                    |   10 +
 include/btrfs.h            |  416 ++++++++++++++
 include/config_fallbacks.h |    4 +
 include/crc.h              |    8 +
 include/fs.h               |    1 +
 lib/Makefile               |    1 +
 lib/crc32_c.c              |   40 ++
 12 files changed, 1942 insertions(+)
 create mode 100644 common/cmd_btr.c
 create mode 100644 fs/btrfs/Makefile
 create mode 100644 fs/btrfs/btrfs.c
 create mode 100644 include/btrfs.h
 create mode 100644 lib/crc32_c.c

diff --git a/Makefile b/Makefile
index 55bd55c..bd7981d 100644
--- a/Makefile
+++ b/Makefile
@@ -257,6 +257,7 @@ endif
 LIBS-$(CONFIG_OF_EMBED) += dts/libdts.o
 LIBS-y += arch/$(ARCH)/lib/lib$(ARCH).o
 LIBS-y += fs/libfs.o \
+       fs/btrfs/libbtrfs.o \
        fs/cbfs/libcbfs.o \
        fs/cramfs/libcramfs.o \
        fs/ext4/libext4fs.o \
diff --git a/common/Makefile b/common/Makefile
index 719fc23..d1fae56 100644
--- a/common/Makefile
+++ b/common/Makefile
@@ -73,6 +73,7 @@ COBJS-$(CONFIG_CMD_BEDBUG) += bedbug.o cmd_bedbug.o
 COBJS-$(CONFIG_CMD_BMP) += cmd_bmp.o
 COBJS-$(CONFIG_CMD_BOOTLDR) += cmd_bootldr.o
 COBJS-$(CONFIG_CMD_BOOTSTAGE) += cmd_bootstage.o
+COBJS-$(CONFIG_CMD_BTR) += cmd_btr.o
 COBJS-$(CONFIG_CMD_CACHE) += cmd_cache.o
 COBJS-$(CONFIG_CMD_CBFS) += cmd_cbfs.o
 COBJS-$(CONFIG_CMD_CONSOLE) += cmd_console.o
diff --git a/common/cmd_btr.c b/common/cmd_btr.c
new file mode 100644
index 0000000..e22154d
--- /dev/null
+++ b/common/cmd_btr.c
@@ -0,0 +1,65 @@
+/*
+ * (C) Copyright 2013 Codethink Limited
+ * Btrfs port to Uboot by
+ * Adnan Ali <adnan....@codethink.co.uk>
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+/*
+ * Boot support
+ */
+#include <fs.h>
+#include <btrfs.h>
+
+char subvolname[BTRFS_MAX_SUBVOL_NAME];
+
+int do_btr_fsload(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
+{
+       if (argc > 5)
+               strcpy(subvolname, argv[5]);
+       else
+               subvolname[0] = '\0';
+
+       return do_load(cmdtp, flag, argc, argv, FS_TYPE_BTR, 16);
+}
+
+
+U_BOOT_CMD(
+btrload,        7,      0,      do_btr_fsload,
+       "load binary file from a btr filesystem",
+       "<interface> [<dev[:part]>]  <addr> <filename> [subvol_name]\n"
+       "    - Load binary file 'filename' from 'dev' on 'interface'\n"
+       "      to address 'addr' from better filesystem.\n"
+       "      the load stops on end of file.\n"
+       "      subvol_name is used read that file from this subvolume.\n"
+       "      All numeric parameters are assumed to be hex."
+);
+
+static int do_btr_ls(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
+{
+       return do_ls(cmdtp, flag, argc, argv, FS_TYPE_BTR);
+}
+
+U_BOOT_CMD(
+       btrls,  4,      1,      do_btr_ls,
+       "list files in a directory (default /)",
+       "<interface> [<dev[:part]>] [directory]\n"
+       "    - list files from 'dev' on 'interface' in a 'directory'"
+);
+
diff --git a/fs/btrfs/Makefile b/fs/btrfs/Makefile
new file mode 100644
index 0000000..a9e2021
--- /dev/null
+++ b/fs/btrfs/Makefile
@@ -0,0 +1,51 @@
+#
+# (C) Copyright 2006
+# Wolfgang Denk, DENX Software Engineering, w...@denx.de.
+#
+# (C) Copyright 2003
+# Pavel Bartusek, Sysgo Real-Time Solutions AG, p...@sysgo.de
+#
+#
+# See file CREDITS for list of people who contributed to this
+# project.
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License as
+# published by the Free Software Foundation; either version 2 of
+# the License, or (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+# MA 02111-1307 USA
+#
+
+include $(TOPDIR)/config.mk
+
+LIB    = $(obj)libbtrfs.o
+
+AOBJS  =
+COBJS-$(CONFIG_FS_BTR) := btrfs.o
+
+SRCS   := $(AOBJS:.o=.S) $(COBJS-y:.o=.c)
+OBJS   := $(addprefix $(obj),$(AOBJS) $(COBJS-y))
+
+
+all:   $(LIB) $(AOBJS)
+
+$(LIB):        $(obj).depend $(OBJS)
+       $(call cmd_link_o_target, $(OBJS))
+
+#########################################################################
+
+# defines $(obj).depend target
+include $(SRCTREE)/rules.mk
+
+sinclude $(obj).depend
+
+#########################################################################
diff --git a/fs/btrfs/btrfs.c b/fs/btrfs/btrfs.c
new file mode 100644
index 0000000..476585c
--- /dev/null
+++ b/fs/btrfs/btrfs.c
@@ -0,0 +1,1344 @@
+/*
+ * (C) Copyright 2013 Codethink Limited
+ * Btrfs port to Uboot by
+ * Adnan Ali <adnan....@codethink.co.uk>
+
+ * btrfs.c -- readonly btrfs support for syslinux
+ * Some data structures are derivated from btrfs-tools-0.19 ctree.h
+ * Copyright 2009 Intel Corporation; author: alek...@intel.com
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, Inc., 53 Temple Place Ste 330,
+ * Boston MA 02111-1307, USA; either version 2 of the License, or
+ * (at your option) any later version; incorporated herein by reference.
+ *
+ */
+
+#include <common.h>
+#include <btrfs.h>
+#include <command.h>
+#include <config.h>
+#include <crc.h>
+#include <fs.h>
+#include <linux/compiler.h>
+#include <linux/ctype.h>
+#include <linux/stat.h>
+#include <asm/byteorder.h>
+
+unsigned long btr_part_offset;
+static char crc_table_built;
+/* Actual file structures (we don't have malloc yet...) */
+struct file files[BTRFS_MAX_OPEN];
+static u32 btrfs_crc32_table[256];
+static block_dev_desc_t *btrfs_block_dev_desc;
+static disk_partition_t *part_info;
+struct inode parent_inode;
+
+static void btrfs_init_crc32c(void)
+{
+       /* Bit-reflected CRC32C polynomial */
+       crc32c_init(btrfs_crc32_table, 0x82F63B78);
+}
+
+static inline u32 crc32c_le(u32 crc, const char *data, size_t length)
+{
+       return crc32c_cal(crc, data, length, btrfs_crc32_table);
+}
+
+void btrfs_type(char num)
+{
+       switch (num) {
+       case BTRFS_FILE:
+               puts("<FILE>   "); break;
+       case BTRFS_DIR:
+               puts("<DIR>    "); break;
+       case BTRFS_SYMLNK:
+               puts("<SYM>    "); break;
+       default:
+               puts("<UNKNOWN>"); break;
+       }
+}
+
+static inline __le32 next_psector(__le32 psector, uint32_t skip)
+{
+       if (EXTENT_SPECIAL(psector))
+               return psector;
+       else
+               return psector + skip;
+}
+
+static inline __le32 next_pstart(const struct extent *e)
+{
+       return next_psector(e->pstart, e->len);
+}
+
+static inline struct inode *get_inode(struct inode *inode)
+{
+       inode->refcnt++;
+
+       return inode;
+}
+
+/* compare function used for bin_search */
+typedef int (*cmp_func)(void *ptr1, void *ptr2);
+
+static int bin_search(void *ptr, int item_size, void *cmp_item, cmp_func func,
+                             int min, int max, int *slot)
+{
+       int low = min;
+       int high = max;
+       int mid;
+       int ret;
+       unsigned long offset;
+       void *item;
+
+       while (low < high) {
+               mid = (low + high) / 2;
+               offset = mid * item_size;
+
+               item = ptr + offset;
+               ret = func(item, cmp_item);
+
+               if (ret < 0)
+                       low = mid + 1;
+               else if (ret > 0)
+                       high = mid;
+               else {
+                       *slot = mid;
+                       return 0;
+               }
+       }
+       *slot = low;
+
+       return 1;
+}
+
+/* XXX: these should go into the filesystem instance structure */
+static struct btrfs_chunk_map chunk_map;
+static struct btrfs_super_block sb;
+static u64 fs_tree;
+/* compare btrfs chunk map in list*/
+static int btrfs_comp_chunk_map(struct btrfs_chunk_map_item *m1,
+                               struct btrfs_chunk_map_item *m2)
+{
+       if (__le64_to_cpu(m1->logical) > __le64_to_cpu(m2->logical))
+               return 1;
+
+       if (__le64_to_cpu(m1->logical) < __le64_to_cpu(m2->logical))
+               return -1;
+
+       return 0;
+}
+
+/* insert a new chunk mapping item */
+static void insert_map(struct btrfs_chunk_map_item *item)
+{
+       int ret;
+       int slot;
+       int i;
+
+       if (chunk_map.map == NULL) { /* first item */
+               chunk_map.map_length = BTRFS_MAX_CHUNK_ENTRIES;
+               chunk_map.map = (struct btrfs_chunk_map_item *)
+                       malloc(chunk_map.map_length * sizeof(*chunk_map.map));
+               chunk_map.map[0] = *item;
+               chunk_map.cur_length = 1;
+
+               return;
+       }
+       ret = bin_search(chunk_map.map, sizeof(*item), item,
+                               (cmp_func)btrfs_comp_chunk_map, 0,
+                               chunk_map.cur_length, &slot);
+       if (ret == 0)/* already in map */
+               return;
+
+       if (chunk_map.cur_length == BTRFS_MAX_CHUNK_ENTRIES) {
+               /* should be impossible */
+               puts("too many chunk items\n");
+               return;
+       }
+       for (i = chunk_map.cur_length; i > slot; i--)
+               chunk_map.map[i] = chunk_map.map[i-1];
+       chunk_map.map[slot] = *item;
+       chunk_map.cur_length++;
+}
+
+/*
+ * from sys_chunk_array or chunk_tree, we can convert a logical address to
+ * a physical address we can not support multi device case yet
+ */
+static u64 logical_physical(u64 logical)
+{
+       struct btrfs_chunk_map_item item;
+       int slot, ret;
+
+       item.logical = logical;
+       ret = bin_search(chunk_map.map, sizeof(*chunk_map.map), &item,
+                       (cmp_func)btrfs_comp_chunk_map, 0,
+                       chunk_map.cur_length, &slot);
+       if (ret == 0)
+               slot++;
+       else if (slot == 0)
+               return -1;
+
+       if (logical >=
+               chunk_map.map[slot-1].logical + chunk_map.map[slot-1].length)
+               return -1;
+
+       return chunk_map.map[slot-1].physical + logical -
+                       chunk_map.map[slot-1].logical;
+}
+
+int btrfs_devread(int sector, int byte_offset, int byte_len, char *buf)
+{
+       ALLOC_CACHE_ALIGN_BUFFER(char, sec_buf, BTRFS_SS);
+       unsigned block_len;
+
+       /* Get the read to the beginning of a partition */
+       sector += byte_offset >> BTRFS_SECTOR_BITS;
+       byte_offset &= BTRFS_SS - 1;
+
+       if (btrfs_block_dev_desc == NULL) {
+               puts("** Invalid Block Device Descriptor (NULL)\n");
+               return 0;
+       }
+       if (byte_offset != 0) {
+               /* read first part which isn't aligned with start of sector */
+               if (btrfs_block_dev_desc->
+                               block_read(btrfs_block_dev_desc->dev,
+                                       part_info->start + sector, 1,
+                                       (unsigned long *) sec_buf) != 1) {
+                       puts(" ** btrfs_devread() read error **\n");
+                       return 0;
+               }
+               memcpy(buf, sec_buf + byte_offset,
+                       min(BTRFS_SS - byte_offset, byte_len));
+               buf += min(BTRFS_SS - byte_offset, byte_len);
+               byte_len -= min(BTRFS_SS - byte_offset, byte_len);
+               sector++;
+       }
+       /* read sector aligned part */
+
+       block_len = byte_len & ~(BTRFS_SS - 1);
+
+       if (block_len == 0) {
+               ALLOC_CACHE_ALIGN_BUFFER(u8, p, BTRFS_SS);
+
+               block_len = BTRFS_SS;
+               btrfs_block_dev_desc->block_read(btrfs_block_dev_desc->dev,
+                                               part_info->start + sector,
+                                               1, (unsigned long *)p);
+               memcpy(buf, p, byte_len);
+               return 1;
+       }
+       ALLOC_CACHE_ALIGN_BUFFER(u8, t, block_len);
+       if (btrfs_block_dev_desc->block_read(btrfs_block_dev_desc->dev,
+                                               part_info->start + sector,
+                                               block_len / BTRFS_SS,
+                                               (unsigned long *) t) !=
+                                               block_len / BTRFS_SS) {
+               debug(" ** %s read error - block\n", __func__);
+               return 0;
+       }
+
+       memcpy(buf, t, block_len);
+       block_len = byte_len & ~(BTRFS_SS - 1);
+       buf += block_len;
+       byte_len -= block_len;
+       sector += block_len / BTRFS_SS;
+       if (byte_len != 0) {
+               /* read rest of data which are not in whole sector */
+               if (btrfs_block_dev_desc->
+                       block_read(btrfs_block_dev_desc->dev,
+                               part_info->start + sector, 1,
+                               (unsigned long *) sec_buf) != 1) {
+                       debug("* %s read error - last part\n", __func__);
+                       return 0;
+               }
+               memcpy(buf, sec_buf, byte_len);
+       }
+
+       return 1;
+}
+/* btrfs has several super block mirrors, need to calculate their location */
+static inline u64 btrfs_sb_offset(int mirror)
+{
+       u64 start = 16 * 1024;
+
+       if (mirror)
+               return start << (BTRFS_SUPER_MIRROR_SHIFT * mirror);
+
+       return BTRFS_SUPER_INFO_OFFSET;
+}
+
+/* find the most recent super block */
+static int btrfs_read_super_block(struct btrfs_info *fs)
+{
+       int i;
+       int ret;
+       u8 fsid[BTRFS_FSID_SIZE];
+       u8 boots[512];
+       u64 offset;
+       u64 transid = 0;
+       struct btrfs_super_block buf;
+
+       sb.total_bytes = ~0;    /* Unknown as of yet */
+
+       /*
+        * Only first header is checked for filesystem verification
+        * mirror of this header can be used if required
+        */
+       /* find most recent super block */
+       for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
+
+               offset = btrfs_sb_offset(i);
+               if (offset >= sb.total_bytes)
+                       break;
+
+               if (btrfs_devread((offset/BTRFS_SS), 0,
+                               sizeof(struct btrfs_super_block),
+                               (char *)&buf) != 1)
+                       return -1;
+
+               if (buf.bytenr != offset ||
+                               strncmp((char *)(&buf.magic),
+                               BTRFS_MAGIC, sizeof(buf.magic)))
+                       return -1;
+
+               if (i == 0)
+                       memcpy(fsid, buf.fsid, sizeof(fsid));
+               else if (memcmp(fsid, buf.fsid, sizeof(fsid))) {
+                       puts("fsid doesn't match\n");
+                       return -1;
+               }
+
+               if (buf.generation > transid) {
+                       memcpy(&sb, &buf, sizeof(sb));
+                       transid = buf.generation;
+               }
+       }
+
+       return 0;
+}
+
+static inline unsigned long btrfs_chunk_item_size(int num_stripes)
+{
+       return sizeof(struct btrfs_chunk) +
+               sizeof(struct btrfs_stripe) * (num_stripes - 1);
+}
+
+static void clear_path(struct btrfs_path *path)
+{
+       memset(path, 0, sizeof(*path));
+}
+
+static int btrfs_comp_keys(struct btrfs_disk_key *k1, struct btrfs_disk_key 
*k2)
+{
+       if (k1->objectid > k2->objectid)
+               return 1;
+       if (k1->objectid < k2->objectid)
+               return -1;
+       if (k1->type > k2->type)
+               return 1;
+       if (k1->type < k2->type)
+               return -1;
+       if (k1->offset > k2->offset)
+               return 1;
+       if (k1->offset < k2->offset)
+               return -1;
+
+       return 0;
+}
+
+/* compare keys but ignore offset, is useful to enumerate all same kind keys */
+static int btrfs_comp_keys_type(struct btrfs_disk_key *k1,
+                                       struct btrfs_disk_key *k2)
+{
+       if (k1->objectid > k2->objectid)
+               return 1;
+       if (k1->objectid < k2->objectid)
+               return -1;
+       if (k1->type > k2->type)
+               return 1;
+       if (k1->type < k2->type)
+               return -1;
+
+       return 0;
+}
+
+/* seach tree directly on disk ... */
+static int search_tree(struct btrfs_info *fs, u64 loffset,
+               struct btrfs_disk_key *key, struct btrfs_path *path)
+{
+       u8 buf[BTRFS_MAX_LEAF_SIZE];
+       struct btrfs_header *header = (struct btrfs_header *)buf;
+       struct btrfs_node *node = (struct btrfs_node *)buf;
+       struct btrfs_leaf *leaf = (struct btrfs_leaf *)buf;
+       int slot, ret;
+       u64 offset;
+
+       offset = logical_physical(loffset);
+       btrfs_devread(offset/BTRFS_SS, (offset%BTRFS_SS),
+                                       sizeof(*header), (char *)header);
+       if (header->level) { /*node*/
+               btrfs_devread(((offset+sizeof(*header))/BTRFS_SS),
+                               ((offset+sizeof(*header))%BTRFS_SS),
+                               __le32_to_cpu(sb.nodesize) - sizeof(*header),
+                               (char *)&node->ptrs[0]);
+               path->itemsnr[header->level] = header->nritems;
+               path->offsets[header->level] = loffset;
+               ret = bin_search(&node->ptrs[0], sizeof(struct btrfs_key_ptr),
+                       key, (cmp_func)btrfs_comp_keys,
+                       path->slots[header->level], header->nritems, &slot);
+               if (ret && slot > path->slots[header->level])
+                       slot--;
+               path->slots[header->level] = slot;
+               ret = search_tree(fs, node->ptrs[slot].blockptr, key, path);
+       } else { /*leaf*/
+               btrfs_devread(((offset+sizeof(*header))/BTRFS_SS),
+                               ((offset+sizeof(*header))%BTRFS_SS),
+                               (sb.leafsize) - sizeof(*header),
+                               (char *)&leaf->items);
+               path->itemsnr[header->level] = header->nritems;
+               path->offsets[0] = loffset;
+               ret = bin_search(&leaf->items[0], sizeof(struct btrfs_item),
+                       key, (cmp_func)btrfs_comp_keys, path->slots[0],
+                       header->nritems, &slot);
+               if (ret && slot > path->slots[header->level])
+                       slot--;
+               path->slots[0] = slot;
+               path->item = leaf->items[slot];
+               btrfs_devread(
+               ((offset + sizeof(*header) + leaf->items[slot].offset)
+                                                               /BTRFS_SS),
+               ((offset + sizeof(*header) + leaf->items[slot].offset)
+                                                               %BTRFS_SS),
+               leaf->items[slot].size, (char *)&path->data);
+       }
+
+       return ret;
+}
+
+/* return 0 if leaf found */
+static int next_leaf(struct btrfs_info *fs, struct btrfs_disk_key *key,
+                                               struct btrfs_path *path)
+{
+       int slot;
+       int level = 1;
+
+       while (level < BTRFS_MAX_LEVEL) {
+               if (!path->itemsnr[level]) /* no more nodes */
+                       return 1;
+
+               slot = path->slots[level] + 1;
+               if (slot >= path->itemsnr[level]) {
+                       level++;
+                       continue;
+               }
+               path->slots[level] = slot;
+               path->slots[level-1] = 0; /* reset low level slots info */
+               search_tree(fs, path->offsets[level], key, path);
+               break;
+       }
+       if (level == BTRFS_MAX_LEVEL)
+               return 1;
+
+       return 0;
+}
+
+/* return 0 if slot found */
+static int next_slot(struct btrfs_info *fs, struct btrfs_disk_key *key,
+                                               struct btrfs_path *path)
+{
+       int slot;
+
+       if (!path->itemsnr[0])
+               return 1;
+
+       slot = path->slots[0] + 1;
+       if (slot >= path->itemsnr[0])
+               return 1;
+
+       path->slots[0] = slot;
+       search_tree(fs, path->offsets[0], key, path);
+
+       return 0;
+}
+
+/*
+ * read chunk_array in super block
+ */
+static void btrfs_read_sys_chunk_array(void)
+{
+       struct btrfs_chunk_map_item item;
+       struct btrfs_disk_key *key;
+       struct btrfs_chunk *chunk;
+       int cur;
+
+       /* read chunk array in superblock */
+       cur = 0;
+
+       while (cur < __le32_to_cpu(sb.sys_chunk_array_size)) {
+               key = (struct btrfs_disk_key *)(sb.sys_chunk_array + cur);
+               cur += sizeof(*key);
+               chunk = (struct btrfs_chunk *)(sb.sys_chunk_array + cur);
+               cur += btrfs_chunk_item_size(chunk->num_stripes);
+               /* insert to mapping table, ignore multi stripes */
+               item.logical = key->offset;
+               item.length = chunk->length;
+               item.devid = chunk->stripe.devid;
+               item.physical = chunk->stripe.offset;/*ignore other stripes */
+               insert_map(&item);
+       }
+}
+
+/* read chunk items from chunk_tree and insert them to chunk map */
+static void btrfs_read_chunk_tree(struct btrfs_info *fs)
+{
+       struct btrfs_disk_key search_key;
+       struct btrfs_chunk *chunk;
+       struct btrfs_chunk_map_item item;
+       struct btrfs_path path;
+       int status;
+
+       if (!(__le64_to_cpu(sb.flags) & BTRFS_SUPER_FLAG_METADUMP)) {
+               if (__le64_to_cpu(sb.num_devices) > 1) {
+                       debug("warning: only support one btrfs device %d\n",
+                               __le64_to_cpu(sb.num_devices));
+                       return;
+               }
+               /* read chunk from chunk_tree */
+               search_key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
+               search_key.type = BTRFS_CHUNK_ITEM_KEY;
+               search_key.offset = 0;
+               clear_path(&path);
+               search_tree(fs, (sb.chunk_root), &search_key, &path);
+               do {
+                       do {
+                               if (btrfs_comp_keys_type(&search_key,
+                                                       &path.item.key))
+                                       break;
+                               chunk = (struct btrfs_chunk *)(path.data);
+                               /* insert to mapping table, ignore stripes */
+                               item.logical = path.item.key.offset;
+                               item.length = chunk->length;
+                               item.devid = chunk->stripe.devid;
+                               item.physical = chunk->stripe.offset;
+                               insert_map(&item);
+                       } while (!next_slot(fs, &search_key, &path));
+                       if (btrfs_comp_keys_type(&search_key, &path.item.key))
+                               break;
+               } while (!next_leaf(fs, &search_key, &path));
+       }
+}
+
+static inline u64 btrfs_name_hash(const char *name, int len)
+{
+       return btrfs_crc32c((u32)~1, name, len);
+}
+
+static struct inode *btrfs_iget_by_inr(struct btrfs_info *fs, u64 inr)
+{
+       struct inode *inode;
+       struct btrfs_inode_item inode_item;
+       struct btrfs_disk_key search_key;
+       struct btrfs_path path;
+       int ret;
+
+       /*
+       *FIXME: some BTRFS inode member are u64, while our logical inode
+       *is u32, we may need change them to u64 later
+       */
+       search_key.objectid = inr;
+       search_key.type = BTRFS_INODE_ITEM_KEY;
+       search_key.offset = 0;
+       clear_path(&path);
+       ret = search_tree(fs, fs_tree, &search_key, &path);
+       if (ret) {
+               debug("%s search_tree failed\n", __func__);
+               return NULL;
+       }
+
+       inode_item = *(struct btrfs_inode_item *)path.data;
+       inode = alloc_inode(fs, inr, sizeof(struct btrfs_pvt_inode));
+       if (!(inode)) {
+               debug("%s alloc_inode failed\n", __func__);
+               return NULL;
+       }
+       inode->ino = inr;
+       inode->size = inode_item.size;
+       inode->mode = BTRFS_IFTODT(inode_item.mode);
+       if (inode->mode == BTRFS_DT_REG || inode->mode == BTRFS_DT_LNK) {
+               struct btrfs_file_extent_item extent_item;
+               u64 offset;
+
+               /* get file_extent_item */
+               search_key.type = BTRFS_EXTENT_DATA_KEY;
+               search_key.offset = 0;
+               clear_path(&path);
+               ret = search_tree(fs, fs_tree, &search_key, &path);
+               if (ret)
+                       return NULL; /* impossible */
+               extent_item = *(struct btrfs_file_extent_item *)path.data;
+               if (extent_item.type == BTRFS_FILE_EXTENT_INLINE)
+                       offset = path.offsets[0] + sizeof(struct btrfs_header)
+                               + path.item.offset
+                               + offsetof(struct btrfs_file_extent_item,
+                                                               disk_bytenr);
+               else
+                       offset = extent_item.disk_bytenr;
+               PVT(inode)->offset = offset;
+       }
+
+       return inode;
+}
+
+static struct inode *btrfs_iget_root(struct btrfs_info *fs)
+{
+       /* BTRFS_FIRST_CHUNK_TREE_OBJECTID(256) actually
+        * is first OBJECTID for FS_TREE
+        */
+       return btrfs_iget_by_inr(fs, BTRFS_FIRST_CHUNK_TREE_OBJECTID);
+}
+
+static struct inode *btrfs_iget(const char *name, struct inode *parent)
+{
+       struct btrfs_info *fs = parent->fs;
+       struct btrfs_disk_key search_key;
+       struct btrfs_path path;
+       struct btrfs_dir_item dir_item;
+       int ret;
+
+       search_key.objectid = parent->ino;
+       search_key.type = BTRFS_DIR_ITEM_KEY;
+       search_key.offset = btrfs_name_hash(name, strlen(name));
+       clear_path(&path);
+       ret = search_tree(fs, fs_tree, &search_key, &path);
+       if (ret)
+               return NULL;
+
+       dir_item = *(struct btrfs_dir_item *)path.data;
+
+       return btrfs_iget_by_inr(fs, dir_item.location.objectid);
+}
+
+static int btrfs_readlink(struct inode *inode, char *buf)
+{
+       btrfs_devread((logical_physical(PVT(inode)->offset)/BTRFS_SS),
+               (logical_physical(PVT(inode)->offset)%BTRFS_SS),
+                                       inode->size, (char *)buf);
+       buf[inode->size] = '\0';
+       return inode->size;
+}
+
+static int btrfs_readdir(struct file *file, struct btrfs_dirent *btrfs_dirent)
+{
+       struct btrfs_info *fs = file->fs;
+       struct inode *inode = file->inode;
+       struct btrfs_disk_key search_key;
+       struct btrfs_path path;
+       struct btrfs_dir_item *dir_item;
+       int ret;
+
+       /*
+        * we use file->offset to store last search key.offset, will will search
+        * key that lower that offset, 0 means first search and we will search
+        * -1UL, which is the biggest possible key
+        */
+       search_key.objectid = inode->ino;
+       search_key.type = BTRFS_DIR_ITEM_KEY;
+       search_key.offset = file->offset - 1;
+       clear_path(&path);
+       ret = search_tree(fs, fs_tree, &search_key, &path);
+
+       if (ret) {
+               if (btrfs_comp_keys_type(&search_key, &path.item.key))
+                       return -1;
+       }
+
+       dir_item = (struct btrfs_dir_item *)path.data;
+       file->offset = path.item.key.offset;
+       btrfs_dirent->d_ino = dir_item->location.objectid;
+       btrfs_dirent->d_off = file->offset;
+       btrfs_dirent->d_reclen = offsetof(struct btrfs_dirent, d_name)
+               + dir_item->name_len + 1;
+       btrfs_dirent->d_type = BTRFS_IFTODT(dir_item->type);
+       memcpy(btrfs_dirent->d_name, dir_item + 1, dir_item->name_len);
+       btrfs_dirent->d_name[dir_item->name_len] = '\0';
+       btrfs_type(dir_item->type);
+       printf("   %s\n", btrfs_dirent->d_name);
+
+       return 0;
+}
+
+static int btrfs_next_extent(struct inode *inode, uint32_t lstart)
+{
+       struct btrfs_disk_key search_key;
+       struct btrfs_file_extent_item extent_item;
+       struct btrfs_path path;
+       int ret;
+       u64 offset;
+       struct btrfs_info *fs = inode->fs;
+       u32 sec_shift = BTRFS_SECTOR_BITS;
+       u32 sec_size = BTRFS_SS;
+
+       search_key.objectid = inode->ino;
+       search_key.type = BTRFS_EXTENT_DATA_KEY;
+       search_key.offset = lstart << sec_shift;
+       clear_path(&path);
+       ret = search_tree(fs, fs_tree, &search_key, &path);
+       if (ret) { /* impossible */
+               puts("btrfs: search extent data error\n");
+               return -1;
+       }
+       extent_item = *(struct btrfs_file_extent_item *)path.data;
+
+       if (extent_item.encryption) {
+               puts("btrfs: found encrypted data, cannot continue\n");
+               return -1;
+       }
+       if (extent_item.compression) {
+               puts("btrfs: found compressed data, cannot continue\n");
+               return -1;
+       }
+
+       if (extent_item.type == BTRFS_FILE_EXTENT_INLINE) {/* inline file */
+               /* we fake a extent here, and PVT of inode will tell us */
+               offset = path.offsets[0] + sizeof(struct btrfs_header)
+                       + path.item.offset
+                       + offsetof(struct btrfs_file_extent_item, disk_bytenr);
+               inode->next_extent.len =
+                       (inode->size + sec_size - 1) >> sec_shift;
+       } else {
+               offset = extent_item.disk_bytenr + extent_item.offset;
+               inode->next_extent.len =
+                       (extent_item.num_bytes + sec_size - 1) >> sec_shift;
+       }
+       inode->next_extent.pstart =
+               logical_physical(offset) >> sec_shift;
+       PVT(inode)->offset = offset;
+
+       return 0;
+}
+
+static uint32_t btrfs_getfssec(struct file *file, char *buf, int sectors,
+                                       char *have_more)
+{
+       u32 ret;
+       struct btrfs_info *fs = file->fs;
+       u32 off = PVT(file->inode)->offset % BTRFS_SS;
+       char handle_inline = 0;
+
+       if (off && !file->offset) {/* inline file first read patch */
+               file->inode->size += off;
+               handle_inline = 1;
+       }
+       ret = generic_getfssec(file, buf, sectors, have_more);
+       if (!ret)
+               return ret;
+
+       off = PVT(file->inode)->offset % BTRFS_SS;
+       if (handle_inline) {/* inline file patch */
+               ret -= off;
+               memcpy(buf, buf + off, ret);
+       }
+
+       return ret;
+}
+
+static void btrfs_get_fs_tree(struct btrfs_info *fs)
+{
+       struct btrfs_disk_key search_key;
+       struct btrfs_path path;
+       struct btrfs_root_item *tree;
+       char subvol_ok = 0;
+
+       /* check if subvol is filled by installer */
+       if (*subvolname) {
+               search_key.objectid = BTRFS_FS_TREE_OBJECTID;
+               search_key.type = BTRFS_ROOT_REF_KEY;
+               search_key.offset = 0;
+               clear_path(&path);
+               if (search_tree(fs, __le64_to_cpu(sb.root), &search_key, &path))
+                       next_slot(fs, &search_key, &path);
+               do {
+                       do {
+                               struct btrfs_root_ref *ref;
+                               int pathlen;
+
+                               if (btrfs_comp_keys_type(&search_key,
+                                                       &path.item.key))
+                                       break;
+                               ref = (struct btrfs_root_ref *)path.data;
+                               pathlen =
+                               path.item.size - sizeof(struct btrfs_root_ref);
+
+                               debug("sub_vol found %s\n", (char *)(ref+1));
+                               if (!strncmp((char *)(ref + 1),
+                                               subvolname, pathlen)) {
+                                       subvol_ok = 1;
+                                       break;
+                               }
+                       } while (!next_slot(fs, &search_key, &path));
+                       if (subvol_ok)
+                               break;
+                       if (btrfs_comp_keys_type(&search_key, &path.item.key))
+                               break;
+               } while (!next_leaf(fs, &search_key, &path));
+               if (!subvol_ok)
+                       puts("no subvol found\n");
+       }
+       /* find fs_tree from tree_root */
+       if (subvol_ok)
+               search_key.objectid = path.item.key.offset;
+       else /* "default" volume */
+               search_key.objectid = BTRFS_FS_TREE_OBJECTID;
+       search_key.type = BTRFS_ROOT_ITEM_KEY;
+       search_key.offset = -1;
+       clear_path(&path);
+       search_tree(fs, (sb.root), &search_key, &path);
+       tree = (struct btrfs_root_item *)path.data;
+       fs_tree = tree->bytenr;
+}
+
+/* init. the fs meta data, return the block size shift bits. */
+int btrfs_fs_init(struct btrfs_info *fs)
+{
+       if (!crc_table_built) { /*Build crc table once*/
+               btrfs_init_crc32c();
+               crc_table_built = 1;
+       }
+
+       btrfs_read_super_block(fs);
+       if (strncmp((char *)(&sb.magic), BTRFS_MAGIC, sizeof(sb.magic)))
+               return -1;
+
+       btrfs_read_sys_chunk_array();
+       btrfs_read_chunk_tree(fs);
+       btrfs_get_fs_tree(fs);
+       fs->root = btrfs_iget_root(fs);
+       parent_inode = *(fs->root);
+
+       return 1;
+}
+static inline uint16_t file_to_handle(struct file *file)
+{
+       return file ? (file - files) + 1 : 0;
+}
+
+static inline struct file *handle_to_file(uint16_t handle)
+{
+       return handle ? &files[handle - 1] : NULL;
+}
+
+/*
+ * Free a refcounted inode
+ */
+void put_inode(struct inode *inode)
+{
+       while (inode && --inode->refcnt == 0) {
+               struct inode *dead = inode;
+               inode = inode->parent;
+               if (dead->name)
+                       free((char *)dead->name);
+               free(dead);
+       }
+}
+
+/*
+ * Get a new inode structure
+ */
+struct inode *alloc_inode(struct btrfs_info *fs, uint32_t ino, size_t data)
+{
+       struct inode *inode = malloc(sizeof(struct inode) + data);
+
+       if (inode) {
+               inode->fs = fs;
+               inode->ino = ino;
+               inode->refcnt = 1;
+       }
+
+       return inode;
+}
+
+/*
+ * Get an empty file structure
+ */
+static struct file *alloc_file(void)
+{
+       int i;
+       struct file *file = files;
+
+       for (i = 0; i < BTRFS_MAX_OPEN; i++) {
+               if (!file->fs)
+                       return file;
+
+               file++;
+       }
+
+       return NULL;
+}
+
+/*
+ * Close and free a file structure
+ */
+static inline void free_file(struct file *file)
+{
+       memset(file, 0, sizeof *file);
+}
+
+void close_file(struct file *file)
+{
+       if (file->inode) {
+               file->offset = 0;
+               put_inode(file->inode);
+       }
+}
+
+void btrfs_close_file(struct file *file)
+{
+       if (file->fs)
+               close_file(file);
+       free_file(file);
+}
+
+void btrfs_mangle_name(char *dst, const char *src)
+{
+       char *p = dst, ch, len;
+       int i = BTRFS_FILENAME_MAX-1;
+
+       len = strlen(src);
+       ch = *src;
+       while (!isspace(ch)) {
+               if (*src == '/') {
+                       if (src[1] == '/') {
+                               src++;
+                               i--;
+                               continue;
+                       }
+               }
+               if (!len)
+                       break;
+               i--;
+               len--;
+               *dst++ = *src++;
+               ch = *src;
+       }
+       while (1) {
+               if (dst == p)
+                       break;
+               if (dst[-1] != '/')
+                       break;
+               if ((dst[-1] == '/') && ((dst - 1) == p))
+                       break;
+
+               dst--;
+               i++;
+       }
+
+       i++;
+       for (; i > 0; i--)
+               *dst++ = '\0';
+
+}
+int btrfs_open_file(const char *name, struct com32_filedata *filedata)
+{
+       int rv;
+       struct file *file;
+       char mangled_name[BTRFS_FILENAME_MAX];
+
+       btrfs_mangle_name(mangled_name, name);
+       rv = searchdir(mangled_name);
+       if (rv < 0)
+               return rv;
+
+       file = handle_to_file(rv);
+       filedata->size      = file->inode->size;
+       filedata->handle    = rv;
+
+       return rv;
+}
+
+int searchdir(const char *name)
+{
+       struct inode *inode = NULL;
+       struct inode *parent = &parent_inode;
+       struct file *file;
+       char *pathbuf = NULL;
+       char *part, *p, echar;
+       int symlink_count = BTRFS_MAX_SYMLINK_CNT;
+
+       file = alloc_file();
+       if (!(file))
+               goto err_no_close;
+
+       p = pathbuf = strdup(name);
+       if (!pathbuf)
+               goto err;
+
+       do {
+got_link:
+               if (*p == '/') {
+                       put_inode(parent);
+                       parent =  &parent_inode;
+               }
+
+               do {
+                       inode = get_inode(parent);
+
+                       while (*p == '/')
+                               p++;
+
+                       if (!*p)
+                               break;
+
+                       part = p;
+                       while ((echar = *p) && echar != '/')
+                               p++;
+                       *p++ = '\0';
+                       if (part[0] == '.' && part[1] == '.' &&
+                                               part[2] == '\0') {
+                               if (inode->parent) {
+                                       put_inode(parent);
+                                       parent = get_inode(inode->parent);
+                                       put_inode(inode);
+                                       inode = NULL;
+                                       if (!echar) {
+                                               /* Terminal double dots */
+                                               inode = parent;
+                                               parent = inode->parent ?
+                                               get_inode(inode->parent) : NULL;
+                                       }
+                               }
+                       } else if (part[0] != '.' || part[1] != '\0') {
+                               inode = btrfs_iget(part, parent);
+                               if (!inode)
+                                       goto err;
+                               if (inode->mode == BTRFS_DT_LNK) {
+                                       char *linkbuf, *q;
+                                       int name_len = echar ? strlen(p) : 0;
+                                       int total_len = inode->size +
+                                                       name_len + 2;
+                                       int link_len;
+
+                                       if (--symlink_count == 0 ||
+                                       total_len > BTRFS_MAX_SYMLINK_BUF)
+                                               goto err;
+
+                                       linkbuf = malloc(total_len);
+                                       if (!linkbuf)
+                                               goto err;
+
+                                       link_len =
+                                               btrfs_readlink(inode, linkbuf);
+                                       if (link_len <= 0) {
+                                               free(linkbuf);
+                                               goto err;
+                                       }
+
+                                       q = linkbuf + link_len;
+
+                                       if (echar) {
+                                               if (link_len > 0 &&
+                                                               q[-1] != '/')
+                                                       *q++ = '/';
+                                               memcpy(q, p, name_len+1);
+                                       } else {
+                                               *q = '\0';
+                                       }
+
+                                       free(pathbuf);
+                                       p = pathbuf = linkbuf;
+                                       put_inode(inode);
+                                       inode = NULL;
+                                       goto got_link;
+                               }
+
+                               inode->name = strdup(part);
+
+                               inode->parent = parent;
+                               parent = NULL;
+
+                               if (!echar)
+                                       break;
+
+                               if (inode->mode != BTRFS_DT_DIR)
+                                       goto err;
+
+                               parent = inode;
+                               inode = NULL;
+                       }
+               } while (echar);
+       } while (0);
+
+       free(pathbuf);
+       pathbuf = NULL;
+       put_inode(parent);
+       parent = NULL;
+
+       if (!inode)
+               goto err;
+
+       file->inode  = inode;
+       file->offset = 0;
+
+       return file_to_handle(file);
+
+err:
+       put_inode(inode);
+       put_inode(parent);
+       if (pathbuf != NULL)
+               free(pathbuf);
+       btrfs_close_file(file);
+err_no_close:
+       return -1;
+}
+
+static void get_next_extent(struct inode *inode)
+{
+       /* The logical start address that we care about... */
+       uint32_t lstart = inode->this_extent.lstart + inode->this_extent.len;
+
+       if (btrfs_next_extent(inode, lstart))
+               inode->next_extent.len = 0; /* ERROR */
+       inode->next_extent.lstart = lstart;
+}
+
+int getfssec(struct com32_filedata *filedata, char * buf)
+{
+       int sectors;
+       char have_more;
+       uint32_t bytes_read;
+       struct file *file;
+       uint16_t handle;
+       if (filedata->size >= 512) {
+               sectors = filedata->size/BTRFS_SS;
+               sectors += (filedata->size%BTRFS_SS) ? 1 : 0;
+       } else
+               sectors = 2;
+
+       file = handle_to_file(filedata->handle);
+
+       bytes_read = btrfs_getfssec(file, buf, sectors, &have_more);
+
+       return bytes_read;
+}
+
+uint32_t generic_getfssec(struct file *file, char *buf,
+                               int sectors, char *have_more)
+{
+       struct inode *inode = file->inode;
+       struct btrfs_info *fs = file->fs;
+       uint32_t bytes_read = 0;
+       uint32_t bytes_left = inode->size - file->offset;
+       uint32_t sectors_left = (bytes_left + BTRFS_SS - 1) >> 9;
+       uint32_t lsector;
+
+       if (sectors > sectors_left)
+               sectors = sectors_left;
+
+       if (!sectors)
+               return 0;
+
+       lsector = file->offset >> 9;
+
+       if (lsector < inode->this_extent.lstart ||
+               lsector >= inode->this_extent.lstart + inode->this_extent.len) {
+               /* inode->this_extent unusable, maybe next_extent is... */
+               inode->this_extent = inode->next_extent;
+       }
+
+       if (lsector < inode->this_extent.lstart ||
+       lsector >= inode->this_extent.lstart + inode->this_extent.len) {
+               /* Still nothing useful... */
+               inode->this_extent.lstart = lsector;
+               inode->this_extent.len = 0;
+       } else {
+               /* We have some usable information */
+               uint32_t delta = lsector - inode->this_extent.lstart;
+               inode->this_extent.lstart = lsector;
+               inode->this_extent.len -= delta;
+               inode->this_extent.pstart
+                   = next_psector(inode->this_extent.pstart, delta);
+       }
+
+       while (sectors) {
+               uint32_t chunk;
+               size_t len;
+
+               while (sectors > inode->this_extent.len) {
+                       if (!inode->next_extent.len ||
+                               inode->next_extent.lstart !=
+                               inode->this_extent.lstart +
+                                               inode->this_extent.len)
+                               get_next_extent(inode);
+                       if (!inode->this_extent.len) {
+                               /* Doesn't matter if it's contiguous... */
+                               inode->this_extent = inode->next_extent;
+                               if (!inode->next_extent.len) {
+                                       sectors = 0; /* Failed to get anything*/
+                                       break;
+                               }
+                       } else if (inode->next_extent.len &&
+                               inode->next_extent.pstart ==
+                                       next_pstart(&inode->this_extent)) {
+                               /* Coalesce extents and loop */
+                               inode->this_extent.len +=
+                                               inode->next_extent.len;
+                       } else {
+                               /* Discontiguous extents */
+                               break;
+                       }
+               }
+
+               chunk = min(sectors, inode->this_extent.len);
+               len = chunk << 9;
+
+               if (inode->this_extent.pstart == BTRFS_EXTENT_ZERO) {
+                       memset(buf, 0, len);
+               } else {
+                       btrfs_block_dev_desc->block_read(
+                               btrfs_block_dev_desc->dev, part_info->start +
+                               (inode->this_extent.pstart), chunk, buf);
+                       inode->this_extent.pstart += chunk;
+               }
+
+                buf += len;
+               sectors -= chunk;
+               bytes_read += len;
+               inode->this_extent.lstart += chunk;
+               inode->this_extent.len -= chunk;
+       }
+
+       bytes_read = min(bytes_read, bytes_left);
+       file->offset += bytes_read;
+
+       if (have_more)
+               *have_more = bytes_read < bytes_left;
+
+       return bytes_read;
+}
+
+/*
+ * Open a directory
+ */
+struct _DIR_ *opendir(const char *path)
+{
+       int rv;
+       struct file *file;
+       rv = searchdir(path);
+       if (rv < 0)
+               return NULL;
+
+       file = handle_to_file(rv);
+
+       if (file->inode->mode != BTRFS_DT_DIR) {
+               btrfs_close_file(file);
+               return NULL;
+       }
+
+       return (struct _DIR_ *)file;
+}
+
+/*
+ * Read one directory entry at one time
+ */
+struct btrfs_dirent *readdir(struct _DIR_ *dir)
+{
+       static struct btrfs_dirent buf;
+       struct file *dd_dir = (struct file *)dir;
+       int rv = -1;
+
+       if (dd_dir)
+               rv = btrfs_readdir(dd_dir, &buf);
+
+       return rv < 0 ? NULL : &buf;
+}
+
+/*
+ *  Btrfs file-system Interface
+ *
+ */
+
+struct btrfs_info fs;
+
+/*
+ *  mount btrfs file-system
+ */
+int btrfs_probe(block_dev_desc_t *rbdd, disk_partition_t *info)
+{
+       btrfs_block_dev_desc = rbdd;
+       part_info = info;
+       btr_part_offset = info->start;
+       if (btrfs_fs_init(&fs) < 0) {
+               puts("btrfs probe failed\n");
+               return -1;
+       }
+
+       return 0;
+}
+
+/*
+ *  Read file data
+ */
+int btrfs_read_file(const char *filename, void *buf, int offset, int len)
+{
+       int file_len = 0;
+       int len_read;
+       struct com32_filedata filedata;
+       int handle;
+       if (offset != 0) {
+               puts("** Cannot support non-zero offset **\n");
+               return -1;
+       }
+
+       handle = btrfs_open_file(filename, &filedata);
+       if (handle < 0) {
+               debug("** File not found %s Invalid handle**\n", filename);
+               return -1;
+       }
+
+       /*file handle is valid get the size of the file*/
+       len = filedata.size;
+       if (len == 0)
+               len = file_len;
+
+       len_read = getfssec(&filedata, (char *)buf);
+       if (len_read != len) {
+               debug("** Unable to read file %s **\n", filename);
+               return -1;
+       }
+
+       return len_read;
+}
+
+/*
+ * Show directory entries
+ */
+int btrfs_ls(char *dirname)
+{
+       struct btrfs_dirent *de;
+       struct _DIR_ *dir;
+
+       if (*dirname == '/' && *(dirname+1) == 0)
+               *dirname = '.';
+
+       dir = opendir(dirname);
+       if (dir == NULL)
+               return -1;
+
+       /* readdir prints contents on media*/
+       de = readdir(dir);
+       while (de != NULL)
+               de = readdir(dir);
+
+       return 0;
+}
+
+/*
+ *  umount btrfs file-system
+ */
+void btrfs_close(void)
+{
+}
diff --git a/fs/fs.c b/fs/fs.c
index 6f5063c..b8c3603 100644
--- a/fs/fs.c
+++ b/fs/fs.c
@@ -17,6 +17,7 @@
 #include <config.h>
 #include <common.h>
 #include <part.h>
+#include <btrfs.h>
 #include <ext4fs.h>
 #include <fat.h>
 #include <fs.h>
@@ -88,6 +89,15 @@ static struct fstype_info fstypes[] = {
                .read = fs_read_sandbox,
        },
 #endif
+#ifdef CONFIG_FS_BTR
+       {
+               .fstype = FS_TYPE_BTR,
+               .probe = btrfs_probe,
+               .close = btrfs_close,
+               .ls = btrfs_ls,
+               .read = btrfs_read_file,
+       },
+#endif
        {
                .fstype = FS_TYPE_ANY,
                .probe = fs_probe_unsupported,
diff --git a/include/btrfs.h b/include/btrfs.h
new file mode 100644
index 0000000..b069a9c
--- /dev/null
+++ b/include/btrfs.h
@@ -0,0 +1,416 @@
+#ifndef _BTRFS_H_
+#define _BTRFS_H_
+
+#include <asm/byteorder.h>
+/* type that store on disk, but it is same as cpu type for i386 arch */
+
+#define BTRFS_CURRENTDIR_MAX           15
+#define BTRFS_MAX_OPEN                 5
+#define BTRFS_FILENAME_MAX             20
+#define BTRFS_MAX_SYMLINK_CNT          20
+#define BTRFS_MAX_SYMLINK_BUF          4096
+#define BTRFS_SECTOR_SHIFT(fs)         ((fs)->sector_shift)
+#define BTRFS_IFTODT(mode)             (((mode) & 0170000) >> 12)
+#define BTRFS_SECTOR_SIZE              0x200
+#define BTRFS_SECTOR_BITS              9
+#define BTRFS_EXTENT_ZERO              ((uint32_t)-1) /* All-zero extent */
+#define BTRFS_EXTENT_VOID              ((uint32_t)-2) /* Invalid information */
+#define BTRFS_DT_LNK                   10
+#define BTRFS_DT_REG                   8
+#define BTRFS_DT_DIR                   4
+#define EXTENT_SPECIAL(x)              ((x) >= BTRFS_EXTENT_VOID)
+#define BTRFS_MAX_SUBVOL_NAME          50
+
+#define BTRFS_FILE                     1
+#define BTRFS_DIR                      2
+#define BTRFS_SYMLNK                   7
+#define BTRFS_SS                       BTRFS_SECTOR_SIZE
+
+extern char subvolname[BTRFS_MAX_SUBVOL_NAME];
+struct _DIR_;
+
+struct com32_filedata {
+       size_t size;                /* File size */
+       int blocklg2;               /* log2(block size) */
+       uint16_t handle;            /* File handle */
+};
+
+struct btrfs_info {
+       const struct fs_ops *fs_ops;
+       struct device *fs_dev;
+       void *fs_info;             /* The fs-specific information */
+       int sector_shift, sector_size;
+       int block_shift, block_size;
+       struct inode *root, *cwd;           /* Root and current directories */
+       char cwd_name[BTRFS_CURRENTDIR_MAX]; /* Current directory by name */
+};
+/*
+ * Extent structure: contains the mapping of some chunk of a file
+ * that is contiguous on disk.
+ */
+struct extent {
+       uint64_t   pstart;
+       uint32_t    lstart;         /* Logical start sector */
+       uint32_t    len;            /* Number of contiguous sectors */
+} __packed;
+
+
+struct inode {
+       struct fs_info *fs;  /* The filesystem this inode is associated with */
+       struct inode *parent;       /* Parent directory, if any */
+       const u8 *name;           /* Name, valid for generic path search only */
+       uint32_t          refcnt;
+       uint32_t       mode;   /* FILE , DIR or SYMLINK */
+       uint32_t     size;
+       uint32_t     blocks; /* How many blocks the file take */
+       uint32_t     ino;    /* Inode number */
+       uint32_t     atime;  /* Access time */
+       uint32_t     mtime;  /* Modify time */
+       uint32_t     ctime;  /* Create time */
+       uint32_t     dtime;  /* Delete time */
+       uint32_t     flags;
+       uint32_t     file_acl;
+       struct extent this_extent, next_extent;
+       u8         pvt[0]; /* Private filesystem data */
+} __packed;
+struct file {
+       struct fs_info *fs;
+       uint64_t offset;            /* for next read */
+       struct inode *inode;        /* The file-specific information */
+} __packed;
+
+#define NAME_MAX 20
+struct btrfs_dirent {
+       uint32_t d_ino;
+       uint32_t d_off;
+       uint16_t d_reclen;
+       uint16_t d_type;
+       char d_name[NAME_MAX + 1];
+};
+
+#define btrfs_crc32c                   crc32c_le
+
+#define BTRFS_SUPER_INFO_OFFSET                (64 * 1024)
+#define BTRFS_SUPER_INFO_SIZE          4096
+#define BTRFS_MAX_LEAF_SIZE            4096
+#define BTRFS_BLOCK_SHIFT              12
+
+#define BTRFS_SUPER_MIRROR_MAX         3
+#define BTRFS_SUPER_MIRROR_SHIFT       12
+#define BTRFS_CSUM_SIZE                        32
+#define BTRFS_FSID_SIZE                        16
+#define BTRFS_LABEL_SIZE               256
+#define BTRFS_SYSTEM_CHUNK_ARRAY_SIZE  2048
+#define BTRFS_UUID_SIZE                        16
+
+#define BTRFS_MAGIC                    "_BHRfS_M"
+
+#define BTRFS_SUPER_FLAG_METADUMP      (1ULL << 33)
+
+#define BTRFS_DEV_ITEM_KEY             216
+#define BTRFS_CHUNK_ITEM_KEY           228
+#define BTRFS_ROOT_REF_KEY             156
+#define BTRFS_ROOT_ITEM_KEY            132
+#define BTRFS_EXTENT_DATA_KEY          108
+#define BTRFS_DIR_ITEM_KEY             84
+#define BTRFS_INODE_ITEM_KEY           1
+
+#define BTRFS_EXTENT_TREE_OBJECTID     2ULL
+#define BTRFS_FS_TREE_OBJECTID         5ULL
+
+#define BTRFS_FIRST_CHUNK_TREE_OBJECTID        256ULL
+
+#define BTRFS_FILE_EXTENT_INLINE       0
+#define BTRFS_FILE_EXTENT_REG          1
+#define BTRFS_FILE_EXTENT_PREALLOC     2
+
+#define BTRFS_MAX_LEVEL                        8
+#define BTRFS_MAX_CHUNK_ENTRIES                256
+
+#define BTRFS_FT_REG_FILE              1
+#define BTRFS_FT_DIR                   2
+#define BTRFS_FT_SYMLINK               7
+
+#define ROOT_DIR_WORD                  0x002f
+
+struct btrfs_dev_item {
+       uint64_t devid;
+       uint64_t total_bytes;
+       uint64_t bytes_used;
+       uint32_t io_align;
+       uint32_t io_width;
+       uint32_t sector_size;
+       uint64_t type;
+       uint64_t generation;
+       uint64_t start_offset;
+       uint32_t dev_group;
+       u8 seek_speed;
+       u8 bandwidth;
+       u8 uuid[BTRFS_UUID_SIZE];
+       u8 fsid[BTRFS_UUID_SIZE];
+} __packed;
+
+struct btrfs_super_block {
+       u8 csum[BTRFS_CSUM_SIZE];
+       /* the first 4 fields must match struct btrfs_header */
+       u8 fsid[BTRFS_FSID_SIZE];    /* FS specific uuid */
+       uint64_t bytenr; /* this block number */
+       uint64_t flags;
+
+       /* allowed to be different from the btrfs_header from here own down */
+       uint64_t magic;
+       uint64_t generation;
+       uint64_t root;
+       uint64_t chunk_root;
+       uint64_t log_root;
+
+       /* this will help find the new super based on the log root */
+       uint64_t log_root_transid;
+       uint64_t total_bytes;
+       uint64_t bytes_used;
+       uint64_t root_dir_objectid;
+       uint64_t num_devices;
+       uint32_t sectorsize;
+       uint32_t nodesize;
+       uint32_t leafsize;
+       uint32_t stripesize;
+       uint32_t sys_chunk_array_size;
+       uint64_t chunk_root_generation;
+       uint64_t compat_flags;
+       uint64_t compat_ro_flags;
+       uint64_t incompat_flags;
+       __le16 csum_type;
+       u8 root_level;
+       u8 chunk_root_level;
+       u8 log_root_level;
+       struct btrfs_dev_item dev_item;
+
+       char label[BTRFS_LABEL_SIZE];
+
+       uint64_t cache_generation;
+
+       /* future expansion */
+       uint64_t reserved[31];
+       u8 sys_chunk_array[BTRFS_SYSTEM_CHUNK_ARRAY_SIZE];
+} __packed;
+struct btrfs_disk_key {
+       uint64_t objectid;
+       u8 type;
+       uint64_t offset;
+} __packed;
+
+struct btrfs_stripe {
+       uint64_t devid;
+       uint64_t offset;
+       u8 dev_uuid[BTRFS_UUID_SIZE];
+} __packed;
+
+struct btrfs_chunk {
+       uint64_t length;
+       uint64_t owner;
+       uint64_t stripe_len;
+       uint64_t type;
+       uint32_t io_align;
+       uint32_t io_width;
+       uint32_t sector_size;
+       __le16 num_stripes;
+       __le16 sub_stripes;
+       struct btrfs_stripe stripe;
+} __packed;
+
+struct btrfs_header {
+       /* these first four must match the super block */
+       u8 csum[BTRFS_CSUM_SIZE];
+       u8 fsid[BTRFS_FSID_SIZE]; /* FS specific uuid */
+       uint64_t bytenr; /* which block this node is supposed to live in */
+       uint64_t flags;
+
+       /* allowed to be different from the super from here on down */
+       u8 chunk_tree_uuid[BTRFS_UUID_SIZE];
+       uint64_t generation;
+       uint64_t owner;
+       uint32_t nritems;
+       u8 level;
+} __packed;
+
+struct btrfs_item {
+       struct btrfs_disk_key key;
+       uint32_t offset;
+       uint32_t size;
+} __packed;
+
+struct btrfs_leaf {
+       struct btrfs_header header;
+       struct btrfs_item items[];
+} __packed;
+
+struct btrfs_key_ptr {
+       struct btrfs_disk_key key;
+       uint64_t blockptr;
+       uint64_t generation;
+} __packed;
+
+struct btrfs_node {
+       struct btrfs_header header;
+       struct btrfs_key_ptr ptrs[];
+} __packed;
+
+/* remember how we get to a node/leaf */
+struct btrfs_path {
+       uint64_t offsets[BTRFS_MAX_LEVEL];
+       uint32_t itemsnr[BTRFS_MAX_LEVEL];
+       uint32_t slots[BTRFS_MAX_LEVEL];
+       /* remember last slot's item and data */
+       struct btrfs_item item;
+       u8 data[BTRFS_MAX_LEAF_SIZE];
+} __packed;
+
+/* store logical offset to physical offset mapping */
+struct btrfs_chunk_map_item {
+       uint64_t logical;
+       uint64_t length;
+       uint64_t devid;
+       uint64_t physical;
+} __packed;
+
+struct btrfs_chunk_map {
+       struct btrfs_chunk_map_item *map;
+       uint32_t map_length;
+       uint32_t cur_length;
+} __packed;
+
+struct btrfs_timespec {
+       uint64_t sec;
+       uint32_t nsec;
+} __packed;
+
+struct btrfs_inode_item {
+       /* nfs style generation number */
+       uint64_t generation;
+       /* transid that last touched this inode */
+       uint64_t transid;
+       uint64_t size;
+       uint64_t nbytes;
+       uint64_t block_group;
+       uint32_t nlink;
+       uint32_t uid;
+       uint32_t gid;
+       uint32_t mode;
+       uint64_t rdev;
+       uint64_t flags;
+
+       /* modification sequence number for NFS */
+       uint64_t sequence;
+
+       /*
+        * a little future expansion, for more than this we can
+        * just grow the inode item and version it
+        */
+       uint64_t reserved[4];
+       struct btrfs_timespec atime;
+       struct btrfs_timespec ctime;
+       struct btrfs_timespec mtime;
+       struct btrfs_timespec otime;
+} __packed;
+
+struct btrfs_root_item {
+       struct btrfs_inode_item inode;
+       uint64_t generation;
+       uint64_t root_dirid;
+       uint64_t bytenr;
+       uint64_t byte_limit;
+       uint64_t bytes_used;
+       uint64_t last_snapshot;
+       uint64_t flags;
+       uint32_t refs;
+       struct btrfs_disk_key drop_progress;
+       u8 drop_level;
+       u8 level;
+} __packed;
+
+struct btrfs_dir_item {
+       struct btrfs_disk_key location;
+       uint64_t transid;
+       __le16 data_len;
+       __le16 name_len;
+       u8 type;
+} __packed;
+
+struct btrfs_file_extent_item {
+       uint64_t generation;
+       uint64_t ram_bytes;
+       u8 compression;
+       u8 encryption;
+       __le16 other_encoding; /* spare for later use */
+       u8 type;
+       uint64_t disk_bytenr;
+       uint64_t disk_num_bytes;
+       uint64_t offset;
+       uint64_t num_bytes;
+} __packed;
+
+struct btrfs_root_ref {
+       uint64_t dirid;
+       uint64_t sequence;
+       __le16 name_len;
+} __packed;
+
+/*
+ * btrfs private inode information
+ */
+struct btrfs_pvt_inode {
+       uint64_t offset;
+} __packed;
+
+
+int btrfs_probe(block_dev_desc_t *rbdd , disk_partition_t *info);
+
+/*
+ *search through disk and mount file-system
+ */
+int btrfs_fs_init(struct btrfs_info *fs);
+
+/*
+ *save inode in list
+ */
+void put_inode(struct inode *inode);
+
+/*
+ *memory allocation for new inode
+ */
+struct inode *alloc_inode(struct btrfs_info *fs, uint32_t ino, size_t data);
+
+/*
+ * open btrfs file
+ */
+int btrfs_open_file(const char *name, struct com32_filedata *filedata);
+/*
+ * reading data from file
+ */
+int getfssec(struct com32_filedata *filedata, char *buf);
+uint32_t generic_getfssec(struct file *file, char *buf,
+                               int sectors, char *have_more);
+
+/*
+ * mount btrfs file-system
+ */
+int btrfs_probe(block_dev_desc_t *rbdd , disk_partition_t *info);
+
+/*
+ * listing file/directory on btrfs partition/disk
+ */
+int btrfs_ls(char *);
+
+/*
+ * read file data
+ */
+int btrfs_read_file(const char *filename, void *buf, int offset, int len);
+
+/*
+ * umount btrfs file-system
+ */
+void btrfs_close(void);
+
+#define PVT(i) ((struct btrfs_pvt_inode *)((i)->pvt))
+
+#endif
diff --git a/include/config_fallbacks.h b/include/config_fallbacks.h
index bfb9680..28a0a66 100644
--- a/include/config_fallbacks.h
+++ b/include/config_fallbacks.h
@@ -26,4 +26,8 @@
 #define CONFIG_EXT4_WRITE
 #endif
 
+#if defined(CONFIG_CMD_BTR) && !defined(CONFIG_FS_BTR)
+#define CONFIG_FS_BTR
+#endif
+
 #endif /* __CONFIG_FALLBACKS_H */
diff --git a/include/crc.h b/include/crc.h
index 10560c9..5e5b1f0 100644
--- a/include/crc.h
+++ b/include/crc.h
@@ -97,4 +97,12 @@ cyg_ether_crc32_accumulate(uint32_t crc, unsigned char *s, 
int len);
 
 extern uint16_t cyg_crc16(unsigned char *s, int len);
 
+/* CRC init for btrfs file-system*/
+
+void crc32c_init(u32 *crc32c_table, u32 pol);
+
+/* CRC calculate for btrfs file-system*/
+
+u32 crc32c_cal(u32 crc, const char *data, size_t length, u32 *crc32c_table);
+
 #endif /* _SERVICES_CRC_CRC_H_ */
diff --git a/include/fs.h b/include/fs.h
index b6d69e5..a8b97ea 100644
--- a/include/fs.h
+++ b/include/fs.h
@@ -22,6 +22,7 @@
 #define FS_TYPE_FAT    1
 #define FS_TYPE_EXT    2
 #define FS_TYPE_SANDBOX        3
+#define FS_TYPE_BTR    4
 
 /*
  * Tell the fs layer which block device an partition to use for future
diff --git a/lib/Makefile b/lib/Makefile
index 86ca1a6..9518b72 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -67,6 +67,7 @@ COBJS-$(CONFIG_SPL_NET_SUPPORT) += hashtable.o
 COBJS-$(CONFIG_SPL_NET_SUPPORT) += net_utils.o
 endif
 COBJS-y += crc32.o
+COBJS-y += crc32_c.o
 COBJS-y += ctype.o
 COBJS-y += div64.o
 COBJS-y += linux_string.o
diff --git a/lib/crc32_c.c b/lib/crc32_c.c
new file mode 100644
index 0000000..b97c98a
--- /dev/null
+++ b/lib/crc32_c.c
@@ -0,0 +1,40 @@
+/*
+ * Copied from Linux kernel crypto/crc32c.c
+ * Copyright (c) 2004 Cisco Systems, Inc.
+ * Copyright (c) 2008 Herbert Xu <herb...@gondor.apana.org.au>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ *
+ */
+#include <linux/stat.h>
+#include <command.h>
+#include <asm/byteorder.h>
+#include <linux/compiler.h>
+#include <common.h>
+#include <config.h>
+
+u32 crc32c_cal(u32 crc, const char *data, size_t length, u32 *crc32c_table)
+{
+       while (length--)
+               crc = crc32c_table[(u8)(crc ^ *data++)] ^ (crc >> 8);
+
+       return crc;
+}
+
+void crc32c_init(u32 *crc32c_table, u32 pol)
+{
+       int i, j;
+       u32 v;
+       const u32 poly = pol; /* Bit-reflected CRC32C polynomial */
+
+       for (i = 0; i < 256; i++) {
+               v = i;
+               for (j = 0; j < 8; j++)
+                       v = (v >> 1) ^ ((v & 1) ? poly : 0);
+
+               crc32c_table[i] = v;
+       }
+}
-- 
1.7.9.5

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