Commit d8f5fead authored by Xiaodong Liu's avatar Xiaodong Liu Committed by Jim Harris
Browse files

nbd: avoid unlimited wait for device busy 



The ioctl NBD_SET_SOCK can return EBUSY on conditions not
only the kernel module hasn't loaded entirely yet, but
also the nbd device is setup by another process, which will
lead the poller's infinite polling.
This patch will wait only 1 second if device is busy.

Change-Id: I8b1cfab725cba180f774a57ced3fa4ba81da2037
Signed-off-by: default avatarXiaodong Liu <xiaodong.liu@intel.com>
Reviewed-on: https://review.gerrithub.io/c/444804


Tested-by: default avatarSPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: default avatarDarek Stojaczyk <dariusz.stojaczyk@intel.com>
Reviewed-by: default avatarPawel Wodkowski <pawelx.wodkowski@intel.com>
Reviewed-by: default avatarBen Walker <benjamin.walker@intel.com>
parent 968a5657

lib/nbd/nbd.c

+8 −4
Original line number Diff line number Diff line
@@ -50,6 +50,8 @@ 
#include "spdk/queue.h"



#define GET_IO_LOOP_COUNT		16

#define NBD_BUSY_WAITING_MS		1000

#define NBD_BUSY_POLLING_INTERVAL_US	20000



enum nbd_io_state_t {

	/* Receiving or ready to receive nbd request header */
@@ -842,6 +844,7 @@ struct spdk_nbd_start_ctx { 
	spdk_nbd_start_cb	cb_fn;

	void			*cb_arg;

	struct spdk_poller	*poller;

	int			polling_count;

};



static void
@@ -907,15 +910,15 @@ spdk_nbd_enable_kernel(void *arg) 


	rc = ioctl(ctx->nbd->dev_fd, NBD_SET_SOCK, ctx->nbd->kernel_sp_fd);

	if (rc == -1) {

		if (errno == EBUSY) {

		if (errno == EBUSY && ctx->polling_count-- > 0) {

			if (ctx->poller == NULL) {

				ctx->poller = spdk_poller_register(spdk_nbd_enable_kernel, ctx, 20000);

				ctx->poller = spdk_poller_register(spdk_nbd_enable_kernel, ctx,

								   NBD_BUSY_POLLING_INTERVAL_US);

			}

			/* If the kernel is busy, check back later */

			return 0;

		}





		SPDK_ERRLOG("ioctl(NBD_SET_SOCK) failed: %s\n", spdk_strerror(errno));

		if (ctx->poller) {

			spdk_poller_unregister(&ctx->poller);
@@ -976,6 +979,7 @@ spdk_nbd_start(const char *bdev_name, const char *nbd_path, 
	ctx->nbd = nbd;

	ctx->cb_fn = cb_fn;

	ctx->cb_arg = cb_arg;

	ctx->polling_count = NBD_BUSY_WAITING_MS * 1000ULL / NBD_BUSY_POLLING_INTERVAL_US;



	rc = spdk_bdev_open(bdev, true, spdk_nbd_bdev_hot_remove, nbd, &nbd->bdev_desc);

	if (rc != 0) {