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Commit 08ba91ee authored by Doron Roberts-Kedes's avatar Doron Roberts-Kedes Committed by Jens Axboe
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nbd: Add the nbd NBD_DISCONNECT_ON_CLOSE config flag. 



If NBD_DISCONNECT_ON_CLOSE is set on a device, then the driver will
issue a disconnect from nbd_release if the device has no remaining
bdev->bd_openers.

Fix ret val so reconfigure with only setting the flag succeeds.

Reviewed-by: default avatarJosef Bacik <josef@toxicpanda.com>
Signed-off-by: default avatarDoron Roberts-Kedes <doronrk@fb.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent ce042c18

drivers/block/nbd.c

+34 −8
Original line number Diff line number Diff line
@@ -76,6 +76,7 @@ struct link_dead_args { 
#define NBD_HAS_CONFIG_REF		4

#define NBD_BOUND			5

#define NBD_DESTROY_ON_DISCONNECT	6

#define NBD_DISCONNECT_ON_CLOSE 	7



struct nbd_config {

	u32 flags;
@@ -138,6 +139,7 @@ static void nbd_config_put(struct nbd_device *nbd); 
static void nbd_connect_reply(struct genl_info *info, int index);

static int nbd_genl_status(struct sk_buff *skb, struct genl_info *info);

static void nbd_dead_link_work(struct work_struct *work);

static void nbd_disconnect_and_put(struct nbd_device *nbd);



static inline struct device *nbd_to_dev(struct nbd_device *nbd)

{
@@ -1305,6 +1307,12 @@ static int nbd_open(struct block_device *bdev, fmode_t mode) 
static void nbd_release(struct gendisk *disk, fmode_t mode)

{

	struct nbd_device *nbd = disk->private_data;

	struct block_device *bdev = bdget_disk(disk, 0);



	if (test_bit(NBD_DISCONNECT_ON_CLOSE, &nbd->config->runtime_flags) &&

			bdev->bd_openers == 0)

		nbd_disconnect_and_put(nbd);



	nbd_config_put(nbd);

	nbd_put(nbd);

}
@@ -1705,6 +1713,10 @@ static int nbd_genl_connect(struct sk_buff *skb, struct genl_info *info) 
				&config->runtime_flags);

			put_dev = true;

		}

		if (flags & NBD_CFLAG_DISCONNECT_ON_CLOSE) {

			set_bit(NBD_DISCONNECT_ON_CLOSE,

				&config->runtime_flags);

		}

	}



	if (info->attrs[NBD_ATTR_SOCKETS]) {
@@ -1749,6 +1761,17 @@ static int nbd_genl_connect(struct sk_buff *skb, struct genl_info *info) 
	return ret;

}



static void nbd_disconnect_and_put(struct nbd_device *nbd)

{

	mutex_lock(&nbd->config_lock);

	nbd_disconnect(nbd);

	nbd_clear_sock(nbd);

	mutex_unlock(&nbd->config_lock);

	if (test_and_clear_bit(NBD_HAS_CONFIG_REF,

			       &nbd->config->runtime_flags))

		nbd_config_put(nbd);

}



static int nbd_genl_disconnect(struct sk_buff *skb, struct genl_info *info)

{

	struct nbd_device *nbd;
@@ -1781,13 +1804,7 @@ static int nbd_genl_disconnect(struct sk_buff *skb, struct genl_info *info) 
		nbd_put(nbd);

		return 0;

	}

	mutex_lock(&nbd->config_lock);

	nbd_disconnect(nbd);

	nbd_clear_sock(nbd);

	mutex_unlock(&nbd->config_lock);

	if (test_and_clear_bit(NBD_HAS_CONFIG_REF,

			       &nbd->config->runtime_flags))

		nbd_config_put(nbd);

	nbd_disconnect_and_put(nbd);

	nbd_config_put(nbd);

	nbd_put(nbd);

	return 0;
@@ -1798,7 +1815,7 @@ static int nbd_genl_reconfigure(struct sk_buff *skb, struct genl_info *info) 
	struct nbd_device *nbd = NULL;

	struct nbd_config *config;

	int index;

	int ret = -EINVAL;

	int ret = 0;

	bool put_dev = false;



	if (!netlink_capable(skb, CAP_SYS_ADMIN))
@@ -1838,6 +1855,7 @@ static int nbd_genl_reconfigure(struct sk_buff *skb, struct genl_info *info) 
	    !nbd->task_recv) {

		dev_err(nbd_to_dev(nbd),

			"not configured, cannot reconfigure\n");

		ret = -EINVAL;

		goto out;

	}
@@ -1862,6 +1880,14 @@ static int nbd_genl_reconfigure(struct sk_buff *skb, struct genl_info *info) 
					       &config->runtime_flags))

				refcount_inc(&nbd->refs);

		}



		if (flags & NBD_CFLAG_DISCONNECT_ON_CLOSE) {

			set_bit(NBD_DISCONNECT_ON_CLOSE,

					&config->runtime_flags);

		} else {

			clear_bit(NBD_DISCONNECT_ON_CLOSE,

					&config->runtime_flags);

		}

	}



	if (info->attrs[NBD_ATTR_SOCKETS]) {

include/uapi/linux/nbd.h

+3 −0
Original line number Diff line number Diff line
@@ -53,6 +53,9 @@ enum { 
/* These are client behavior specific flags. */

#define NBD_CFLAG_DESTROY_ON_DISCONNECT	(1 << 0) /* delete the nbd device on

						    disconnect. */

#define NBD_CFLAG_DISCONNECT_ON_CLOSE (1 << 1) /* disconnect the nbd device on

						*  close by last opener.

						*/



/* userspace doesn't need the nbd_device structure */