Btrfs-progs: Add chunk recover function - using old chunk items

Add chunk-recover program to check or rebuild chunk tree when the system
chunk array or chunk tree is broken.

Due to the importance of the system chunk array and chunk tree, if one of
them is broken, the whole btrfs will be broken even other data are OK.

But we have some hint(fsid, checksum...) to salvage the old metadata.
So this function will first scan the whole file system and collect the
needed data(chunk/block group/dev extent), and check for the references
between them. If the references are OK, the chunk tree can be rebuilt and
luckily the file system will be mountable.

Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/commands.h b/commands.h
index 15c616d..65829f4 100644
--- a/commands.h
+++ b/commands.h
@@ -94,6 +94,7 @@ extern const struct cmd_group replace_cmd_group;
 extern const char * const cmd_send_usage[];
 extern const char * const cmd_receive_usage[];
 extern const char * const cmd_check_usage[];
+extern const char * const cmd_chunk_recover_usage[];
 extern const char * const cmd_restore_usage[];
 
 int cmd_subvolume(int argc, char **argv);
@@ -102,6 +103,7 @@ int cmd_balance(int argc, char **argv);
 int cmd_device(int argc, char **argv);
 int cmd_scrub(int argc, char **argv);
 int cmd_check(int argc, char **argv);
+int cmd_chunk_recover(int argc, char **argv);
 int cmd_inspect(int argc, char **argv);
 int cmd_send(int argc, char **argv);
 int cmd_receive(int argc, char **argv);