-----Original Message----- From: Jรกn Tomko [mailto:jtomko@redhat.com] Sent: Friday, January 16, 2015 10:21 PM To: Chen, Hanxiao/้ ๆ้; libvir-list@redhat.com Subject: Re: [libvirt] [PATCH 1/2] Introduce btrfsCloneFile for btrfs COW copy
On 01/13/2015 09:18 AM, Chen Hanxiao wrote:
Signed-off-by: Chen Hanxiao <chenhanxiao@cn.fujitsu.com> --- 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) +
Instead of redefining the constants, can we check for btrfs.h at configure time and wrap the function in #ifdef BTRFS_IOC_CLONE ?
We need to install btrfs-progs-devel for BTRFS_IOC_CLONE in <btrfs/ioctl.h>. So it should be easy to just define magic number and issue a ioctl, than add a dependency on btrfs-progs-devel. Do we need to add a LIBVIRT_CHECK_PKG for btrfs-progs-devel? Thanks, - Chen