Commit 516310a5 authored by Alex Michon's avatar Alex Michon Committed by Tomasz Zawadzki
Browse files

lib/blob: Clear cluster before releasing due to unneeded allocation 



When we allocate a cluster, we may copy parent data to the new cluster.
After this copy is done, we may realize that another IO channel already
allocated the cluster so we no longer need the cluster. We need to
release it. But we need to clear the data. Otherwise, another blob may
claim the cluster and may see garbage data instead of zeroes.

Change-Id: Ib3fb9d4a264371bcaa224855ad0c3c1bbdc93979
Signed-off-by: default avatarAlex Michon <amichon@kalrayinc.com>
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/19231


Reviewed-by: default avatarTomasz Zawadzki <tomasz.zawadzki@intel.com>
Tested-by: default avatarSPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: default avatarJim Harris <jim.harris@samsung.com>
Community-CI: Mellanox Build Bot
parent b6e74c0d

lib/blob/blobstore.c

+51 −6
Original line number Diff line number Diff line
@@ -1725,10 +1725,10 @@ struct spdk_blob_persist_ctx { 
};



static void

bs_batch_clear_dev(struct spdk_blob_persist_ctx *ctx, spdk_bs_batch_t *batch, uint64_t lba,

bs_batch_clear_dev(struct spdk_blob *blob, spdk_bs_batch_t *batch, uint64_t lba,

		   uint64_t lba_count)

{

	switch (ctx->blob->clear_method) {

	switch (blob->clear_method) {

	case BLOB_CLEAR_WITH_DEFAULT:

	case BLOB_CLEAR_WITH_UNMAP:

		bs_batch_unmap_dev(batch, lba, lba_count);
@@ -1981,7 +1981,7 @@ blob_persist_clear_clusters(spdk_bs_sequence_t *seq, struct spdk_blob_persist_ct 


		/* If a run of LBAs previously existing, clear them now */

		if (lba_count > 0) {

			bs_batch_clear_dev(ctx, batch, lba, lba_count);

			bs_batch_clear_dev(ctx->blob, batch, lba, lba_count);

		}



		/* Start building the next batch */
@@ -1995,7 +1995,7 @@ blob_persist_clear_clusters(spdk_bs_sequence_t *seq, struct spdk_blob_persist_ct 


	/* If we ended with a contiguous set of LBAs, clear them now */

	if (lba_count > 0) {

		bs_batch_clear_dev(ctx, batch, lba, lba_count);

		bs_batch_clear_dev(ctx->blob, batch, lba, lba_count);

	}



	bs_batch_close(batch);
@@ -2603,6 +2603,49 @@ blob_insert_cluster_revert(struct spdk_blob_copy_cluster_ctx *ctx) 
	spdk_spin_unlock(&ctx->blob->bs->used_lock);

}



static void

blob_insert_cluster_clear_cpl(void *cb_arg, int bserrno)

{

	struct spdk_blob_copy_cluster_ctx *ctx = cb_arg;



	if (bserrno) {

		SPDK_WARNLOG("Failed to clear cluster: %d\n", bserrno);

	}



	blob_insert_cluster_revert(ctx);

	bs_sequence_finish(ctx->seq, bserrno);

}



static void

blob_insert_cluster_clear(struct spdk_blob_copy_cluster_ctx *ctx)

{

	struct spdk_bs_cpl cpl;

	spdk_bs_batch_t *batch;

	struct spdk_io_channel *ch = spdk_io_channel_from_ctx(ctx->seq->channel);



	/*

	 * We allocated a cluster and we copied data to it. But now, we realized that we don't need

	 * this cluster and we want to release it. We must ensure that we clear the data on this

	 * cluster.

	 * The cluster may later be re-allocated by a thick-provisioned blob for example. When

	 * reading from this thick-provisioned blob before writing data, we should read zeroes.

	 */



	cpl.type = SPDK_BS_CPL_TYPE_BLOB_BASIC;

	cpl.u.blob_basic.cb_fn = blob_insert_cluster_clear_cpl;

	cpl.u.blob_basic.cb_arg = ctx;



	batch = bs_batch_open(ch, &cpl, ctx->blob);

	if (!batch) {

		blob_insert_cluster_clear_cpl(ctx, -ENOMEM);

		return;

	}



	bs_batch_clear_dev(ctx->blob, batch, bs_cluster_to_lba(ctx->blob->bs, ctx->new_cluster),

			   bs_cluster_to_lba(ctx->blob->bs, 1));

	bs_batch_close(batch);

}



static void

blob_insert_cluster_cpl(void *cb_arg, int bserrno)

{
@@ -2611,10 +2654,12 @@ blob_insert_cluster_cpl(void *cb_arg, int bserrno) 
	if (bserrno) {

		if (bserrno == -EEXIST) {

			/* The metadata insert failed because another thread

			 * allocated the cluster first. Free our cluster

			 * allocated the cluster first. Clear and free our cluster

			 * but continue without error. */

			bserrno = 0;

			blob_insert_cluster_clear(ctx);

			return;

		}



		blob_insert_cluster_revert(ctx);

	}