Patchwork [U-Boot,v8] Introduced btrfs file-system with btrload command

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Submitter Adnan Ali
Date March 18, 2013, 1:23 p.m.
Message ID <1363613000-29473-2-git-send-email-adnan.ali@codethink.co.uk>
Download mbox | patch
Permalink /patch/228649/
State Changes Requested
Delegated to: Tom Rini
Headers show

Comments

Adnan Ali - March 18, 2013, 1:23 p.m.
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.

v8:     patch re-formated.
v7:     patch re-formated.
v6:     patch re-formated.
v5:     merged with master.
v4:     btrls command added.

Signed-off-by: Adnan Ali <adnan.ali@codethink.co.uk>
---
 Makefile                   |    1 +
 common/Makefile            |    1 +
 common/cmd_btr.c           |   65 +++
 fs/btrfs/Makefile          |   51 ++
 fs/btrfs/btrfs.c           | 1352 ++++++++++++++++++++++++++++++++++++++++++++
 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, 1950 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
Tom Rini - March 19, 2013, 2:35 p.m.
On Mon, Mar 18, 2013 at 01:23:20PM +0000, Adnan Ali wrote:

> 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.
> 
> v8:     patch re-formated.
> v7:     patch re-formated.
> v6:     patch re-formated.
> v5:     merged with master.
> v4:     btrls command added.
> 
> Signed-off-by: Adnan Ali <adnan.ali@codethink.co.uk>

I'm sorry, but there's still some pretty severe checkpatch warnings
introduced here over syslinux such as:
ERROR: do not use assignment in if condition
#525: FILE: btrfs/btrfs.c:525:
+                               if (status = btrfs_comp_keys_type(&search_key,

Please use "./tools/checkpatch.pl -f fs/btrfs/btrfs.c" and -f
/path/to/syslinux/core/fs/btrfs/btrfs.c and fix the things that are
being introduced and quite possibly bugs like the above.
Adnan Ali - March 19, 2013, 3:25 p.m.
Hi

On 19/03/13 14:35, Tom Rini wrote:
> On Mon, Mar 18, 2013 at 01:23:20PM +0000, Adnan Ali wrote:
>
>> 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.
>>
>> v8:     patch re-formated.
>> v7:     patch re-formated.
>> v6:     patch re-formated.
>> v5:     merged with master.
>> v4:     btrls command added.
>>
>> Signed-off-by: Adnan Ali <adnan.ali@codethink.co.uk>
> I'm sorry, but there's still some pretty severe checkpatch warnings
> introduced here over syslinux such as:
> ERROR: do not use assignment in if condition
> #525: FILE: btrfs/btrfs.c:525:
> +                               if (status = btrfs_comp_keys_type(&search_key,
>
> Please use "./tools/checkpatch.pl -f fs/btrfs/btrfs.c" and -f
> /path/to/syslinux/core/fs/btrfs/btrfs.c and fix the things that are
> being introduced and quite possibly bugs like the above.
>
      Thanks, I am going to remove all the errors. Do you want me to 
remove all
warnings as well or you are fine with it. This has taken quite a while now.


Thanks

Adnan Ali
Tom Rini - March 19, 2013, 3:28 p.m.
On Tue, Mar 19, 2013 at 03:25:47PM +0000, Adnan Ali wrote:
> Hi
> 
> On 19/03/13 14:35, Tom Rini wrote:
> >On Mon, Mar 18, 2013 at 01:23:20PM +0000, Adnan Ali wrote:
> >
> >>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.
> >>
> >>v8:     patch re-formated.
> >>v7:     patch re-formated.
> >>v6:     patch re-formated.
> >>v5:     merged with master.
> >>v4:     btrls command added.
> >>
> >>Signed-off-by: Adnan Ali <adnan.ali@codethink.co.uk>
> >I'm sorry, but there's still some pretty severe checkpatch warnings
> >introduced here over syslinux such as:
> >ERROR: do not use assignment in if condition
> >#525: FILE: btrfs/btrfs.c:525:
> >+                               if (status = btrfs_comp_keys_type(&search_key,
> >
> >Please use "./tools/checkpatch.pl -f fs/btrfs/btrfs.c" and -f
> >/path/to/syslinux/core/fs/btrfs/btrfs.c and fix the things that are
> >being introduced and quite possibly bugs like the above.
> >
>      Thanks, I am going to remove all the errors. Do you want me to
> remove all
> warnings as well or you are fine with it. This has taken quite a while now.

Yes please fix all of the new warnings and errors that are not found in
syslinux sources.  Thanks.

Patch

diff --git a/Makefile b/Makefile
index 55bd55c..b3da594 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..846c0f1
--- /dev/null
+++ b/common/cmd_btr.c
@@ -0,0 +1,65 @@ 
+/*
+ * (C) Copyright 2013 Codethink Limited
+ * Btrfs port to Uboot by
+ * Adnan Ali <adnan.ali@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
+		strcpy(subvolname, "");
+
+	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, wd@denx.de.
+#
+# (C) Copyright 2003
+# Pavel Bartusek, Sysgo Real-Time Solutions AG, pba@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..39e1300
--- /dev/null
+++ b/fs/btrfs/btrfs.c
@@ -0,0 +1,1352 @@ 
+/*
+ * (C) Copyright 2013 Codethink Limited
+ * Btrfs port to Uboot by
+ * Adnan Ali <adnan.ali@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.du@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;
+extern char subvolname[BTRFS_MAX_SUBVOL_NAME];
+
+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:
+		printf("<FILE>   "); break;
+	case BTRFS_DIR:
+		printf("<DIR>    "); break;
+	case BTRFS_SYMLNK:
+		printf("<SYM>    "); break;
+	default:
+		printf("<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 */
+		debug("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_SECTOR_SIZE);
+	unsigned block_len;
+
+	/* Get the read to the beginning of a partition */
+	sector += byte_offset >> BTRFS_SECTOR_BITS;
+	byte_offset &= BTRFS_SECTOR_SIZE - 1;
+
+	if (btrfs_block_dev_desc == NULL) {
+		debug("** 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) {
+			debug(" ** btrfs_devread() read error **\n");
+
+			return 0;
+		}
+		memcpy(buf, sec_buf + byte_offset,
+			min(BTRFS_SECTOR_SIZE - byte_offset, byte_len));
+		buf += min(BTRFS_SECTOR_SIZE - byte_offset, byte_len);
+		byte_len -= min(BTRFS_SECTOR_SIZE - byte_offset, byte_len);
+		sector++;
+	}
+	/* read sector aligned part */
+
+	block_len = byte_len & ~(BTRFS_SECTOR_SIZE - 1);
+
+	if (block_len == 0) {
+		ALLOC_CACHE_ALIGN_BUFFER(u8, p, BTRFS_SECTOR_SIZE);
+
+		block_len = BTRFS_SECTOR_SIZE;
+		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_SECTOR_SIZE,
+						(unsigned long *) t) !=
+						block_len / BTRFS_SECTOR_SIZE) {
+		debug(" ** %s read error - block\n", __func__);
+
+		return 0;
+	}
+
+	memcpy(buf, t, block_len);
+	block_len = byte_len & ~(BTRFS_SECTOR_SIZE - 1);
+	buf += block_len;
+	byte_len -= block_len;
+	sector += block_len / BTRFS_SECTOR_SIZE;
+	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
+	 */
+	offset = btrfs_sb_offset(0);
+
+	if (btrfs_devread(128, 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))) {
+		debug("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_SECTOR_SIZE, (offset%BTRFS_SECTOR_SIZE),
+						sizeof(*header), (char *)header);
+	if (header->level) { /*node*/
+		btrfs_devread(((offset+sizeof(*header))/BTRFS_SECTOR_SIZE),
+					((offset+sizeof(*header))%BTRFS_SECTOR_SIZE),
+			__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_SECTOR_SIZE),
+				((offset+sizeof(*header))%BTRFS_SECTOR_SIZE),
+				(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_SECTOR_SIZE),
+				((offset + sizeof(*header) + leaf->items[slot].offset)%BTRFS_SECTOR_SIZE),
+				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 (status = 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;
+	if (!(inode = alloc_inode(fs, inr, sizeof(struct btrfs_pvt_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) /* inline file */
+			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_SECTOR_SIZE),
+		(logical_physical(PVT(inode)->offset)%BTRFS_SECTOR_SIZE), 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_SECTOR_SIZE;
+
+	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 */
+		debug("btrfs: search extent data error\n");
+
+		return -1;
+	}
+	extent_item = *(struct btrfs_file_extent_item *)path.data;
+
+	if (extent_item.encryption) {
+		debug("btrfs: found encrypted data, cannot continue\n");
+
+		return -1;
+	}
+	if (extent_item.compression) {
+		debug("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_SECTOR_SIZE;
+	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_SECTOR_SIZE;
+	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, status;
+
+				if (status = 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)
+			debug("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;
+
+	if (!(file = alloc_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 (/*!this_fs->fs_ops->readlink ||*/
+					--symlink_count == 0       ||      /* limit check */
+					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_SECTOR_SIZE;
+		sectors += (filedata->size%BTRFS_SECTOR_SIZE) ? 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_SECTOR_SIZE - 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... we're dead */
+					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) {
+		debug("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) {
+		debug("** 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*/
+	while ((de = readdir(dir)) != NULL)
+		;
+
+	return 0;
+}
+
+/*
+ *  umount btrfs file-system
+ */
+void btrfs_close(void)
+{
+}
diff --git a/fs/fs.c b/fs/fs.c
index 6f5063c..58b155c 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..f18ecff
--- /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
+
+
+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 <herbert@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;
+	}
+}