[libvirt] [PATCH] rbd: Remove snapshots if the FORCED flag has been provided

[Daniel P. Berrange]

On Thu, Oct 15, 2015 at 10:28:39AM +0200, Wido den Hollander wrote:
> When a RBD volume has snapshots it can not be removed.
> 
> This patch introduces a new flag to force volume removal,
> VIR_STORAGE_VOL_DELETE_FORCED.
> 
> With this flag any existing snapshots will be removed prior
> to removing the volume.
> 
> No existing mechanism in libvirt allowed us to pass such information,
> so that's why a new flag was introduced.
> 
> Signed-off-by: Wido den Hollander <wido at widodh.nl>
> ---
>  include/libvirt/libvirt-storage.h |  1 +
>  src/storage/storage_backend_rbd.c | 58 +++++++++++++++++++++++++++++++++++++++
>  2 files changed, 59 insertions(+)
> 
> diff --git a/include/libvirt/libvirt-storage.h b/include/libvirt/libvirt-storage.h
> index 453089e..36ff979 100644
> --- a/include/libvirt/libvirt-storage.h
> +++ b/include/libvirt/libvirt-storage.h
> @@ -115,6 +115,7 @@ typedef enum {
>  typedef enum {
>      VIR_STORAGE_VOL_DELETE_NORMAL = 0, /* Delete metadata only    (fast) */
>      VIR_STORAGE_VOL_DELETE_ZEROED = 1 << 0,  /* Clear all data to zeros (slow) */
> +    VIR_STORAGE_VOL_DELETE_FORCED = 2, /* Force removal of volume, even if in use */
>  } virStorageVolDeleteFlags;
>  
>  typedef enum {
> diff --git a/src/storage/storage_backend_rbd.c b/src/storage/storage_backend_rbd.c
> index ac5085a..ca5e802 100644
> --- a/src/storage/storage_backend_rbd.c
> +++ b/src/storage/storage_backend_rbd.c
> @@ -428,9 +428,13 @@ static int virStorageBackendRBDDeleteVol(virConnectPtr conn,
>  {
>      int ret = -1;
>      int r = 0;
> +    int max_snaps = 128;
> +    int i, snap_count, protected;
>      virStorageBackendRBDState ptr;
>      ptr.cluster = NULL;
>      ptr.ioctx = NULL;
> +    rbd_snap_info_t *snaps;
> +    rbd_image_t image = NULL;
>  
>      VIR_DEBUG("Removing RBD image %s/%s", pool->def->source.name, vol->name);
>  
> @@ -443,6 +447,59 @@ static int virStorageBackendRBDDeleteVol(virConnectPtr conn,
>      if (virStorageBackendRBDOpenIoCTX(&ptr, pool) < 0)
>          goto cleanup;
>  
> +    r = rbd_open(ptr.ioctx, vol->name, &image, NULL);
> +    if (r < 0) {
> +       virReportSystemError(-r, _("failed to open the RBD image '%s'"),
> +                            vol->name);
> +       goto cleanup;
> +    }
> +
> +    do {
> +        if (VIR_ALLOC_N(snaps, max_snaps))
> +            goto cleanup;
> +
> +        snap_count = rbd_snap_list(image, snaps, &max_snaps);
> +        if (snap_count <= 0) {
> +            VIR_FREE(snaps);
> +        }
> +    } while (snap_count == -ERANGE);
> +
> +    VIR_DEBUG("Found %d snapshots for volume %s/%s", snap_count,
> +              pool->def->source.name, vol->name);
> +
> +    if (snap_count > 0 && (flags & VIR_STORAGE_VOL_DELETE_FORCED)) {
> +        for (i = 0; i < snap_count; i++) {
> +            if (rbd_snap_is_protected(image, snaps[i].name, &protected))
> +                goto cleanup;
> +
> +            if (protected == 1) {
> +                VIR_DEBUG("Snapshot %s/%s@%s is protected needs to be "
> +                          "unprotected", pool->def->source.name, vol->name,
> +                          snaps[i].name);
> +
> +                if (rbd_snap_unprotect(image, snaps[i].name) < 0)
> +                    goto cleanup;
> +            }
> +
> +            VIR_DEBUG("Removing snapshot %s/%s@%s", pool->def->source.name,
> +                      vol->name, snaps[i].name);
> +
> +            if (rbd_snap_remove(image, snaps[i].name) < 0) {
> +                virReportSystemError(-r, _("failed to remove snapshot '%s/%s@%s'"),

You're reporting '-r' as an errno, but this was last set on the
rbd_open call many lines earlier, so doesn't correspond to the
rbd_snap_remove error.


Regards,
Daniel
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