lib/blobfs: add the missing lock operation

Change-Id: I9d02357688a11d06c5afb3d8be90a1f3b1927333
Signed-off-by: GangCao <gang.cao@intel.com>
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/16266
Reviewed-by: Changpeng Liu <changpeng.liu@intel.com>
Reviewed-by: Aleksey Marchuk <alexeymar@nvidia.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>

lib/blobfs/blobfs.c

@@ -2457,6 +2457,7 @@ spdk_file_write(struct spdk_file *file, struct spdk_fs_thread_ctx *ctx,
 		if (extend_args.rc) {
 			return extend_args.rc;
 		}
+		pthread_spin_lock(&file->lock);
 	}
 
 	flush_req = alloc_fs_request(channel);