Re: [libvirt] [PATCH 2/2] storage: try to perform btrfs COW copy if possible

We don't take advantage of clone of btrfs. So a)try to do a btrfs lightweight copy b)fall back to a standard copy if COW copy not supported. Signed-off-by: Chen Hanxiao <chenhanxiao(a)cn.fujitsu.com&gt; --- include/libvirt/libvirt-storage.h | 1 + src/storage/storage_backend.c | 39 ++++++++++++++++++++++++++++++++------- src/storage/storage_backend_fs.c | 8 ++++++-- src/storage/storage_driver.c | 4 +++- 4 files changed, 42 insertions(+), 10 deletions(-) diff --git a/include/libvirt/libvirt-storage.h b/include/libvirt/libvirt-storage.h index 1f3087b..4ae42e1 100644 --- a/include/libvirt/libvirt-storage.h +++ b/include/libvirt/libvirt-storage.h @@ -306,6 +306,7 @@ const char* virStorageVolGetKey (virStorageVolPtr vol); typedef enum { VIR_STORAGE_VOL_CREATE_PREALLOC_METADATA = 1 << 0, + VIR_STORAGE_VOL_CREATE_REFLINK = 1 << 1,

} virStorageVolCreateFlags; virStorageVolPtr virStorageVolCreateXML (virStoragePoolPtr pool, diff --git a/src/storage/storage_backend.c b/src/storage/storage_backend.c index 5ce3566..838398e 100644 --- a/src/storage/storage_backend.c +++ b/src/storage/storage_backend.c @@ -187,7 +187,8 @@ virStorageBackendCopyToFD(virStorageVolDefPtr vol, virStorageVolDefPtr inputvol, int fd, unsigned long long *total, - bool want_sparse) + bool want_sparse, + bool reflink_copy) { int inputfd = -1; int amtread = -1; @@ -226,6 +227,15 @@ virStorageBackendCopyToFD(virStorageVolDefPtr vol, goto cleanup; } + if (reflink_copy) { + if (btrfsCloneFile(fd, inputfd) == -1) { + VIR_DEBUG("btrfs clone not supported, try another way.");