There is situation that num_extent_pages is zero and original pointer is
also NULL, the realloc() could return a Not NULL pointer.
Related UT has been added and updated.
1) In the default allocation (num_clusters == 0), the extent_pages is not allocated as expected.
2) In the thin provisioning allocation (num_clusters != 0), the extent_pages will be allocated if extent_table is used.
More related information as below:
The crux of the problem is that according to POSIX:
realloc: "If ptr is NULL, then the call is equivalent to malloc(size)"
malloc: "If size is 0, then malloc returns either NULL or a unique pointer value that can later be successfully passed to free"
blobstore was relying on realloc(NULL, 0) always return a unique pointer value, and not NULL. This is not portable behavior.
Change-Id: Ibc28d9696f15a3c0e2aa6bb2371dc23576c28954
Signed-off-by: GangCao <gang.cao@intel.com>
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/10470
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: Changpeng Liu <changpeng.liu@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>
10f32b9f19