Commit 7f139e54 authored by Tomasz Zawadzki's avatar Tomasz Zawadzki
Browse files

lib/blob: extent_page shall never occupy md page 0 



Search for md_page to be used as extent page started
from 0, which is completely valid md_page.

This page can be free when for example blob with id 0
was deleted and some other requested a new page for extent.

There are already existing blobs that have extents
pointing to 0, which means unallocated.
Unfortunetly it means 0 can never mean md page 0.
If that already occured for someone, this extent page was already
lost during blob/bs reload and nothing can be done.

With this in mind following assumptions are made for extent pages:
- 0 means unallocated extent page
- UINT32_MAX means we ran out of md pages, and should not be persisted
- [NEW] extent page can never occupy md page 0

That last one is new addition in this patch.
bs_allocate_cluster will now always try to find md page from 1 or higher.

Signed-off-by: default avatarTomasz Zawadzki <tomasz.zawadzki@intel.com>
Change-Id: Ia17ce5bbca2fab4fb4487e4e263f3a0aa120bf17
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/4314


Tested-by: default avatarSPDK CI Jenkins <sys_sgci@intel.com>
Community-CI: Mellanox Build Bot
Reviewed-by: default avatarBen Walker <benjamin.walker@intel.com>
Reviewed-by: default avatarJim Harris <james.r.harris@intel.com>
Reviewed-by: default avatarShuhei Matsumoto <shuhei.matsumoto.xt@hitachi.com>
parent 63e257ed

lib/blob/blobstore.c

+4 −0
Original line number Diff line number Diff line
@@ -165,6 +165,10 @@ bs_allocate_cluster(struct spdk_blob *blob, uint32_t cluster_num, 
	if (blob->use_extent_table) {

		extent_page = bs_cluster_to_extent_page(blob, cluster_num);

		if (*extent_page == 0) {

			/* Extent page shall never occupy md_page so start the search from 1 */

			if (*lowest_free_md_page == 0) {

				*lowest_free_md_page = 1;

			}

			/* No extent_page is allocated for the cluster */

			*lowest_free_md_page = spdk_bit_array_find_first_clear(blob->bs->used_md_pages,

					       *lowest_free_md_page);

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

+5 −1
Original line number Diff line number Diff line
@@ -3769,7 +3769,7 @@ blob_thin_prov_rw(void) 
{

	static const uint8_t zero[10 * 4096] = { 0 };

	struct spdk_blob_store *bs = g_bs;

	struct spdk_blob *blob;

	struct spdk_blob *blob, *blob_id0;

	struct spdk_io_channel *channel, *channel_thread1;

	struct spdk_blob_opts opts;

	uint64_t free_clusters;
@@ -3788,7 +3788,11 @@ blob_thin_prov_rw(void) 
	ut_spdk_blob_opts_init(&opts);

	opts.thin_provision = true;



	/* Create and delete blob at md page 0, so that next md page allocation

	 * for extent will use that. */

	blob_id0 = ut_blob_create_and_open(bs, &opts);

	blob = ut_blob_create_and_open(bs, &opts);

	ut_blob_close_and_delete(bs, blob_id0);

	CU_ASSERT(free_clusters == spdk_bs_free_cluster_count(bs));



	CU_ASSERT(blob->active.num_clusters == 0);