Commit f118de60 authored Aug 24, 2018 by wuzhouhui Committed by Ben Walker Sep 06, 2018

bdev: fix race condition between spdk_bdev_close and _remove_notify



When new bdev was created, the struct spdk_bdev_module::examine_disk()
may open and close bdev. On the other hand, if something goes wrong,
the creation procedure may unregister new created bdev, so race
condition appeared between _remove_notify() and spdk_bdev_close().

Add the new field "closed" and "remove_notified" in struct spdk_bdev_desc,
so _remove_notify() and spdk_bdev_close() knows how to deal with this
situation.

Change-Id: Ibfe915a4d76096796b039a13a4f49f26669eba2c
Signed-off-by: wuzhouhui <wuzhouhui@kingsoft.com>
Reviewed-on: https://review.gerrithub.io/423369


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>

parent 898739fb

lib/bdev/bdev.c

+14 −2

Original line number	Diff line number	Diff line
		@@ -263,6 +263,7 @@ struct spdk_bdev_desc {
		spdk_bdev_remove_cb_t remove_cb;
		void *remove_ctx;
		bool remove_scheduled;
		bool closed;
		bool write;
		TAILQ_ENTRY(spdk_bdev_desc) link;
		};
		@@ -3174,8 +3175,14 @@ _remove_notify(void *arg)
		{
		struct spdk_bdev_desc *desc = arg;

		desc->remove_scheduled = false;

		if (desc->closed) {
		free(desc);
		} else {
		desc->remove_cb(desc->remove_ctx);
		}
		}

		void
		spdk_bdev_unregister(struct spdk_bdev bdev, spdk_bdev_unregister_cb cb_fn, void cb_arg)
		@@ -3289,7 +3296,12 @@ spdk_bdev_close(struct spdk_bdev_desc *desc)
		pthread_mutex_lock(&bdev->internal.mutex);

		TAILQ_REMOVE(&bdev->internal.open_descs, desc, link);

		desc->closed = true;

		if (!desc->remove_scheduled) {
		free(desc);
		}

		/* If no more descriptors, kill QoS channel */
		if (bdev->internal.qos && TAILQ_EMPTY(&bdev->internal.open_descs)) {