On 01/21/2015 08:06 AM, Chen, Hanxiao wrote:
-----Original Message----- From: libvir-list-bounces@redhat.com [mailto:libvir-list-bounces@redhat.com] On Behalf Of Chen, Hanxiao Sent: Monday, January 19, 2015 2:26 PM To: Ján Tomko; libvir-list@redhat.com Subject: Re: [libvirt] [PATCH 1/2] Introduce btrfsCloneFile for btrfs COW copy
-----Original Message----- From: Ján Tomko [mailto:jtomko@redhat.com] Sent: Friday, January 16, 2015 10:21 PM To: Chen, Hanxiao/陈 晗霄; libvir-list@redhat.com [snip]
+#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?
I can see BTRFS_IOC_CLONE in linux/btrfs.h, which is part of kernel-headers on RHEL 7. Anyway, we should be checking for the header file via AC_CHECK_HEADER (preferably only when we're building with the storage driver that will use it), not a distro-specific package name. Jan