Re: [libvirt] [PATCH 1/2] Introduce btrfsCloneFile for btrfs COW copy

Signed-off-by: Chen Hanxiao <chenhanxiao(a)cn.fujitsu.com&gt; --- src/storage/storage_backend.c | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) diff --git a/src/storage/storage_backend.c b/src/storage/storage_backend.c index b990a82..5ce3566 100644 --- a/src/storage/storage_backend.c +++ b/src/storage/storage_backend.c @@ -156,6 +156,32 @@ enum { #define READ_BLOCK_SIZE_DEFAULT (1024 * 1024) #define WRITE_BLOCK_SIZE_DEFAULT (4 * 1024) +/* + * Perform the O(1) btrfs clone operation, if possible. + * Upon success, return 0. Otherwise, return -1 and set errno. + */ +#if !defined(BTRFS_IOCTL_MAGIC) +# define BTRFS_IOCTL_MAGIC 0x94 +#endif + +#define BTRFS_IOC_CLONE _IOW (BTRFS_IOCTL_MAGIC, 9, int) +