Commit 0f515737 authored by Tomasz Zawadzki's avatar Tomasz Zawadzki
Browse files

lib/blob: merge EP of a clone when deleting a snapshot 



In general it is not possible to delete snapshot when
there are clones on top of it.
There is special case when there is just a single clone
on top that snapshot.

In such case the clone is 'merged' with snapshot.
Unallocated clusters in clone, are filled with the ones
in snapshot (if allocated there).

Similar behavior should have occurred for extent pages.

This patch adds the implementation for moving EP from
snapshot to clone along with UT.

The UT exposes the issue by allowing delete_blob
to proceed beyond just unrecoverable snapshot blob.

Fixes #1291

Signed-off-by: default avatarTomasz Zawadzki <tomasz.zawadzki@intel.com>
Change-Id: Ib2824c5737021f8e8d9b533a4cd245c12e6fe9fa
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/1163


Reviewed-by: default avatarJim Harris <james.r.harris@intel.com>
Reviewed-by: default avatarBen Walker <benjamin.walker@intel.com>
Tested-by: default avatarSPDK CI Jenkins <sys_sgci@intel.com>
parent 4f24f2ca

lib/blob/blobstore.c

+13 −0
Original line number Diff line number Diff line
@@ -6212,7 +6212,14 @@ _spdk_delete_snapshot_sync_clone_cpl(void *cb_arg, int bserrno) 
			ctx->snapshot->active.clusters[i] = 0;

		}

	}

	for (i = 0; i < ctx->snapshot->active.num_extent_pages &&

	     i < ctx->clone->active.num_extent_pages; i++) {

		if (ctx->clone->active.extent_pages[i] == ctx->snapshot->active.extent_pages[i]) {

			ctx->snapshot->active.extent_pages[i] = 0;

		}

	}



	_spdk_blob_set_thin_provision(ctx->snapshot);

	ctx->snapshot->state = SPDK_BLOB_STATE_DIRTY;



	if (ctx->parent_snapshot_entry != NULL) {
@@ -6245,6 +6252,12 @@ _spdk_delete_snapshot_sync_snapshot_xattr_cpl(void *cb_arg, int bserrno) 
			ctx->clone->active.clusters[i] = ctx->snapshot->active.clusters[i];

		}

	}

	for (i = 0; i < ctx->snapshot->active.num_extent_pages &&

	     i < ctx->clone->active.num_extent_pages; i++) {

		if (ctx->clone->active.extent_pages[i] == 0) {

			ctx->clone->active.extent_pages[i] = ctx->snapshot->active.extent_pages[i];

		}

	}



	/* Delete old backing bs_dev from clone (related to snapshot that will be removed) */

	ctx->clone->back_bs_dev->destroy(ctx->clone->back_bs_dev);

test/unit/lib/blob/blob.c/blob_ut.c

+8 −1
Original line number Diff line number Diff line
@@ -5223,6 +5223,7 @@ blob_delete_snapshot_power_failure(void) 
	spdk_blob_id ids[3] = {};

	int rc;

	bool deleted = false;

	int delete_snapshot_bserrno = -1;



	thresholds.general_threshold = 1;

	while (!deleted) {
@@ -5257,6 +5258,7 @@ blob_delete_snapshot_power_failure(void) 


		spdk_bs_delete_blob(bs, snapshotid, blob_op_complete, NULL);

		poll_threads();

		delete_snapshot_bserrno = g_bserrno;



		/* Do not shut down cleanly. Assumption is that after snapshot deletion

		 * reports success, changes to both blobs should already persisted. */
@@ -5294,8 +5296,13 @@ blob_delete_snapshot_power_failure(void) 
			CU_ASSERT(g_bserrno == 0);

		} else {

			CU_ASSERT(spdk_blob_get_parent_snapshot(bs, blobid) == SPDK_BLOBID_INVALID);

			/* Snapshot might have been left in unrecoverable state, so it does not open.

			 * Yet delete might perform further changes to the clone after that.

			 * This UT should test until snapshot is deleted and delete call succeeds. */

			if (delete_snapshot_bserrno == 0) {

				deleted = true;

			}

		}



		spdk_blob_close(blob, blob_op_complete, NULL);

		poll_threads();