In preparation for supporting degraded lvols, spdk_blob_is_degraded() is
added. To support this, bs_dev gains an optional is_degraded() callback.
spdk_blob_is_degraded() returns false so long as no bs_dev that the blob
depends on is degraded. Depended upon bs_devs include the blobstore's
device and the blob's back_bs_dev.
Signed-off-by: Mike Gerdts <mgerdts@nvidia.com>
Change-Id: Ib02227f5735b00038ed30923813e1d5b57deb1ab
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/17516
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: Ben Walker <benjamin.walker@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>
09bf2b2092