[libvirt] [PATCH v3 2/2] Storage : Fix cloning of raw, sparse volumes

When virsh vol-clone is attempted on a raw file where capacity > allocation, the resulting cloned volume has a size that matches the virtual-size of the parent; in place of matching its actual, disk size. This patch fixes the cloned disk to have same _allocated_size_ as the parent file from which it was cloned. Ref: http://www.redhat.com/archives/libvir-list/2015-May/msg00050.html Also fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1130739 Signed-off-by: Prerna Saxena <prerna(a)linux.vnet.ibm.com&gt; --- src/storage/storage_backend.c | 23 ++++++++++------------- src/storage/storage_driver.c | 5 ----- 2 files changed, 10 insertions(+), 18 deletions(-) diff --git a/src/storage/storage_backend.c b/src/storage/storage_backend.c index ce59f63..492b344 100644 --- a/src/storage/storage_backend.c +++ b/src/storage/storage_backend.c @@ -342,7 +342,7 @@ virStorageBackendCreateBlockFrom(virConnectPtr conn ATTRIBUTE_UNUSED, goto cleanup; } - remain = vol->target.allocation; + remain = vol->target.capacity; if (inputvol) { int res = virStorageBackendCopyToFD(vol, inputvol, @@ -397,7 +397,8 @@ createRawFile(int fd, virStorageVolDefPtr vol, virStorageVolDefPtr inputvol, bool reflink_copy) { - bool need_alloc = true; + bool want_sparse = (inputvol && + (inputvol->target.capacity > vol->target.allocation)); int ret = 0; unsigned long long remain; @@ -420,10 +421,9 @@ createRawFile(int fd, virStorageVolDefPtr vol, * to writing zeroes block by block in case fallocate isn't * available, and since we're going to copy data from another * file it doesn't make sense to write the file twice. */ - if (vol->target.allocation) { - if (fallocate(fd, 0, 0, vol->target.allocation) == 0) { - need_alloc = false; - } else if (errno != ENOSYS && errno != EOPNOTSUPP) { + if (vol->target.allocation && !want_sparse) { + if ((fallocate(fd, 0, 0, vol->target.allocation) != 0) && + (errno != ENOSYS && errno != EOPNOTSUPP)) { ret = -errno; virReportSystemError(errno, _("cannot allocate %llu bytes in file '%s'"), @@ -433,22 +433,19 @@ createRawFile(int fd, virStorageVolDefPtr vol, } #endif - remain = vol->target.allocation; + remain = vol->target.capacity; if (inputvol) { /* allow zero blocks to be skipped if we've requested sparse - * allocation (allocation < capacity) or we have already - * been able to allocate the required space. */ - bool want_sparse = !need_alloc || - (vol->target.allocation < inputvol->target.capacity); - + * allocation (allocation < capacity) + */ ret = virStorageBackendCopyToFD(vol, inputvol, fd, &remain, want_sparse, reflink_copy); if (ret < 0) goto cleanup; } - if (remain && need_alloc) { + if (remain && !want_sparse) { if (safezero(fd, vol->target.allocation - remain, remain) < 0) { ret = -errno; virReportSystemError(errno, _("cannot fill file '%s'"), diff --git a/src/storage/storage_driver.c b/src/storage/storage_driver.c index 41de8df..b8ed006 100644 --- a/src/storage/storage_driver.c +++ b/src/storage/storage_driver.c @@ -1976,11 +1976,6 @@ storageVolCreateXMLFrom(virStoragePoolPtr obj, if (newvol->target.capacity < origvol->target.capacity) newvol->target.capacity = origvol->target.capacity; - /* Make sure allocation is at least as large as the destination cap, - * to make absolutely sure we copy all possible contents */ - if (newvol->target.allocation < origvol->target.capacity) - newvol->target.allocation = origvol->target.capacity; - if (!backend->buildVolFrom) { virReportError(VIR_ERR_NO_SUPPORT, "%s", _("storage pool does not support" -- 1.8.3.1 -- Prerna Saxena Linux Technology Centre, IBM Systems and Technology Lab, Bangalore, India