[libvirt] [PATCHv4 2/2] Fix cloning of raw, sparse volumes
John Ferlan
jferlan at redhat.com
Thu Jul 9 14:42:49 UTC 2015
On 07/03/2015 09:54 AM, Ján Tomko wrote:
> From: Prerna Saxena <prerna at linux.vnet.ibm.com>
>
> 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 at linux.vnet.ibm.com>
> Signed-off-by: Ján Tomko <jtomko at redhat.com>
> ---
> src/storage/storage_backend.c | 23 ++++++++++++++---------
> src/storage/storage_driver.c | 5 -----
> 2 files changed, 14 insertions(+), 14 deletions(-)
>
> diff --git a/src/storage/storage_backend.c b/src/storage/storage_backend.c
> index c71545c..bab81e3 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,
> @@ -401,6 +401,12 @@ createRawFile(int fd, virStorageVolDefPtr vol,
> int ret = 0;
> unsigned long long pos = 0;
>
> + /* If the new allocation is lower than the capacity of the orignal file,
s/orignal/original
ACK series
John
> + * the cloned volume will be sparse */
> + if (inputvol &&
> + vol->target.allocation < inputvol->target.capacity)
> + need_alloc = false;
> +
> /* Seek to the final size, so the capacity is available upfront
> * for progress reporting */
> if (ftruncate(fd, vol->target.capacity) < 0) {
> @@ -420,7 +426,7 @@ 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 (vol->target.allocation && need_alloc) {
> if (fallocate(fd, 0, 0, vol->target.allocation) == 0) {
> need_alloc = false;
> } else if (errno != ENOSYS && errno != EOPNOTSUPP) {
> @@ -433,21 +439,20 @@ createRawFile(int fd, virStorageVolDefPtr vol,
> }
> #endif
>
> -
> if (inputvol) {
> - unsigned long long remain = vol->target.allocation;
> + unsigned long long remain = inputvol->target.capacity;
> /* 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);
> -
> ret = virStorageBackendCopyToFD(vol, inputvol, fd, &remain,
> - want_sparse, reflink_copy);
> + !need_alloc, reflink_copy);
> if (ret < 0)
> goto cleanup;
>
> - pos = vol->target.allocation - remain;
> + /* If the new allocation is greater than the original capacity,
> + * but fallocate failed, fill the rest with zeroes.
> + */
> + pos = inputvol->target.capacity - remain;
> }
>
> if (need_alloc) {
> diff --git a/src/storage/storage_driver.c b/src/storage/storage_driver.c
> index e600514..ba27acf 100644
> --- a/src/storage/storage_driver.c
> +++ b/src/storage/storage_driver.c
> @@ -1975,11 +1975,6 @@ 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"
>
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