func findPathRootId(dir *C.DIR) (uint64, error) {
fd := getDirFd(dir)
var args C.struct_btrfs_ioctl_ino_lookup_args
args.objectid = C.BTRFS_FIRST_FREE_OBJECTID
_, _, errno := syscall.Syscall(syscall.SYS_IOCTL, fd, C.BTRFS_IOC_INO_LOOKUP, uintptr(unsafe.Pointer(&args)))
if errno != 0 {
return 0, fmt.Errorf("Failed to perform the inode lookup %v", errno.Error())
}
return uint64(args.treeid), nil
}
func (ila *inodeLookupArgs) C() C.struct_btrfs_ioctl_ino_lookup_args {
var args C.struct_btrfs_ioctl_ino_lookup_args
args.objectid = C.__u64(ila.ObjectID)
args.treeid = C.__u64(ila.TreeID)
if ila.Name != "" {
str := [C.BTRFS_INO_LOOKUP_PATH_MAX]C.char{}
for i := 0; i < len(ila.Name) && i < C.BTRFS_INO_LOOKUP_PATH_MAX; i++ {
str[i] = C.char(ila.Name[i])
}
args.name = str
}
return args
}
func inodeLookup(dirpath string) (*inodeLookupArgs, error) {
dir, err := openDir(dirpath)
if err != nil {
return nil, err
}
defer closeDir(dir)
var inoArgs C.struct_btrfs_ioctl_ino_lookup_args
inoArgs.objectid = C.BTRFS_FIRST_FREE_OBJECTID
_, _, errno := syscall.Syscall(syscall.SYS_IOCTL, getDirFd(dir), C.BTRFS_IOC_INO_LOOKUP,
uintptr(unsafe.Pointer(&inoArgs)))
if errno != 0 {
return nil, fmt.Errorf("Failed to lookup btrfs inode: %v", errno.Error())
}
return newInodeLookupArgs(inoArgs), nil
}
func findRootGen(dir *C.DIR) (uint64, error) {
fd := getDirFd(dir)
var maxFound uint64 = 0
var inoArgs C.struct_btrfs_ioctl_ino_lookup_args
var args C.struct_btrfs_ioctl_search_args
var sk *C.struct_btrfs_ioctl_search_key = &args.key
var sh C.struct_btrfs_ioctl_search_header
inoArgs.objectid = C.BTRFS_FIRST_FREE_OBJECTID
_, _, errno := syscall.Syscall(syscall.SYS_IOCTL, fd, C.BTRFS_IOC_INO_LOOKUP, uintptr(unsafe.Pointer(&inoArgs)))
if errno != 0 {
return 0, fmt.Errorf("Failed to perform the inode lookup %v", errno.Error())
}
sk.tree_id = 1
sk.min_objectid = inoArgs.treeid
sk.max_objectid = inoArgs.treeid
sk.max_type = C.BTRFS_ROOT_ITEM_KEY
sk.min_type = C.BTRFS_ROOT_ITEM_KEY
sk.max_offset = math.MaxUint64
sk.max_transid = math.MaxUint64
sk.nr_items = 4096
for {
_, _, errno := syscall.Syscall(syscall.SYS_IOCTL, fd, C.BTRFS_IOC_TREE_SEARCH, uintptr(unsafe.Pointer(&args)))
if errno != 0 {
return 0, fmt.Errorf("Failed to perform the search %v", errno.Error())
}
if sk.nr_items == 0 {
break
}
var off uintptr = 0
for i := C.__u32(0); i < sk.nr_items; i++ {
var item *C.struct_btrfs_root_item
C.memcpy(unsafe.Pointer(&sh), addptr(unsafe.Pointer(&args.buf), off), C.sizeof_struct_btrfs_ioctl_search_header)
off += C.sizeof_struct_btrfs_ioctl_search_header
item = (*C.struct_btrfs_root_item)(unsafe.Pointer(&args.buf[off]))
off += uintptr(sh.len)
sk.min_objectid = sh.objectid
sk.min_type = sh._type
sk.min_offset = sh.offset
if sh.objectid > inoArgs.treeid {
break
}
if sh.objectid == inoArgs.treeid && sh._type == C.BTRFS_ROOT_ITEM_KEY {
rootGeneration := item.generation
if maxFound < uint64(rootGeneration) {
maxFound = uint64(rootGeneration)
}
}
}
if sk.min_offset < math.MaxUint64 {
sk.min_offset++
} else {
break
}
if sk.min_type != C.BTRFS_ROOT_ITEM_KEY {
break
}
if sk.min_objectid != inoArgs.treeid {
break
}
}
return maxFound, nil
}
