diff mbox

[8/8] target: display 'write_protect' attribute for demo-mode LUNs

Message ID 1434620622-65391-9-git-send-email-hare@suse.de (mailing list archive)
State New, archived
Headers show

Commit Message

Hannes Reinecke June 18, 2015, 9:43 a.m. UTC 
When LUNs are mapped with a demo-mode initiator we're missing
the 'write_protect' attribute to set a LUN read-only.

Signed-off-by: Hannes Reinecke <hare@suse.de>
---
 drivers/target/target_core_device.c          | 27 ++++++++++++++++++
 drivers/target/target_core_fabric_configfs.c | 42 ++++++++++++++++++++++++++++
 drivers/target/target_core_internal.h        |  1 +
 3 files changed, 70 insertions(+)

Comments

Christoph Hellwig June 19, 2015, 6:51 a.m. UTC | #1 
On Thu, Jun 18, 2015 at 11:43:42AM +0200, Hannes Reinecke wrote:
> When LUNs are mapped with a demo-mode initiator we're missing
> the 'write_protect' attribute to set a LUN read-only.

I don't think it's a good idea as-is.  The target core clearly
differenciates between demo mode and production mode read only, and some
drivers already expose attributes for these.

I have a big series in progress to clean the mess around this area
up.  So for now please don't add anything here, it should become much
simpler after my changes, and I might be able to incorporate something
like this after the main series.
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Hannes Reinecke June 19, 2015, 7:05 a.m. UTC | #2 
On 06/19/2015 08:51 AM, Christoph Hellwig wrote:
> On Thu, Jun 18, 2015 at 11:43:42AM +0200, Hannes Reinecke wrote:
>> When LUNs are mapped with a demo-mode initiator we're missing
>> the 'write_protect' attribute to set a LUN read-only.
> 
> I don't think it's a good idea as-is.  The target core clearly
> differenciates between demo mode and production mode read only, and some
> drivers already expose attributes for these.
> 
> I have a big series in progress to clean the mess around this area
> up.  So for now please don't add anything here, it should become much
> simpler after my changes, and I might be able to incorporate something
> like this after the main series.
> 
I've done this particular patch to simulate write-protected LUNs via
tcm_loop. As the hooks already had been there I thought this to be
the 'cleanest' approach.

Of course, if you have other suggestions on how this should be
achieved I'm happy to try this.

Cheers,

Hannes
diff mbox

Patch

diff --git a/drivers/target/target_core_device.c b/drivers/target/target_core_device.c
index 88d6070..3e17070 100644
--- a/drivers/target/target_core_device.c
+++ b/drivers/target/target_core_device.c
@@ -271,6 +271,33 @@  void core_update_device_list_access(
 	mutex_unlock(&nacl->lun_entry_mutex);
 }
 
+void core_update_lun_access(
+	struct se_lun *lun,
+	u32 lun_access)
+{
+	struct se_dev_entry *deve;
+
+	if (lun_access == TRANSPORT_LUNFLAGS_READ_ONLY) {
+		lun->lun_access &= ~TRANSPORT_LUNFLAGS_READ_WRITE;
+		lun->lun_access |= TRANSPORT_LUNFLAGS_READ_ONLY;
+	} else {
+		lun->lun_access &= ~TRANSPORT_LUNFLAGS_READ_ONLY;
+		lun->lun_access |= TRANSPORT_LUNFLAGS_READ_WRITE;
+	}
+
+	spin_lock_bh(&lun->lun_deve_lock);
+	list_for_each_entry(deve, &lun->lun_deve_list, lun_link) {
+		if (lun_access & TRANSPORT_LUNFLAGS_READ_WRITE) {
+			deve->lun_flags &= ~TRANSPORT_LUNFLAGS_READ_ONLY;
+			deve->lun_flags |= TRANSPORT_LUNFLAGS_READ_WRITE;
+		} else {
+			deve->lun_flags &= ~TRANSPORT_LUNFLAGS_READ_WRITE;
+			deve->lun_flags |= TRANSPORT_LUNFLAGS_READ_ONLY;
+		}
+	}
+	spin_unlock_bh(&lun->lun_deve_lock);
+}
+
 /*
  * Called with rcu_read_lock or nacl->device_list_lock held.
  */
diff --git a/drivers/target/target_core_fabric_configfs.c b/drivers/target/target_core_fabric_configfs.c
index 6cfee59..299b4b5 100644
--- a/drivers/target/target_core_fabric_configfs.c
+++ b/drivers/target/target_core_fabric_configfs.c
@@ -726,12 +726,54 @@  static ssize_t target_fabric_port_store_attr_alua_tg_pt_write_md(
 
 TCM_PORT_ATTR(alua_tg_pt_write_md, S_IRUGO | S_IWUSR);
 
+static ssize_t target_fabric_port_show_attr_write_protect(
+	struct se_lun *lun,
+	char *page)
+{
+	ssize_t len = 0;
+
+	if (!lun || !lun->lun_se_dev)
+		return -ENODEV;
+
+	len = sprintf(page, "%d\n",
+		      (lun->lun_access & TRANSPORT_LUNFLAGS_READ_ONLY) ? 1 : 0);
+
+	return len;
+}
+
+static ssize_t target_fabric_port_store_attr_write_protect(
+	struct se_lun *lun,
+	const char *page,
+	size_t count)
+{
+	unsigned long op;
+	int ret;
+
+	if (!lun || !lun->lun_se_dev)
+		return -ENODEV;
+
+	ret = kstrtoul(page, 0, &op);
+	if (ret)
+		return ret;
+
+	if ((op != 1) && (op != 0))
+		return -EINVAL;
+
+	core_update_lun_access(lun, (op) ?
+			       TRANSPORT_LUNFLAGS_READ_ONLY :
+			       TRANSPORT_LUNFLAGS_READ_WRITE);
+
+	return count;
+
+}
+TCM_PORT_ATTR(write_protect, S_IRUGO | S_IWUSR);
 
 static struct configfs_attribute *target_fabric_port_attrs[] = {
 	&target_fabric_port_alua_tg_pt_gp.attr,
 	&target_fabric_port_alua_tg_pt_offline.attr,
 	&target_fabric_port_alua_tg_pt_status.attr,
 	&target_fabric_port_alua_tg_pt_write_md.attr,
+	&target_fabric_port_write_protect.attr,
 	NULL,
 };
 
diff --git a/drivers/target/target_core_internal.h b/drivers/target/target_core_internal.h
index 5111789..69a57a4 100644
--- a/drivers/target/target_core_internal.h
+++ b/drivers/target/target_core_internal.h
@@ -36,6 +36,7 @@  void	core_clear_lun_from_tpg(struct se_lun *, struct se_portal_group *);
 int	core_dev_add_lun(struct se_portal_group *, struct se_device *,
 		struct se_lun *lun);
 void	core_dev_del_lun(struct se_portal_group *, struct se_lun *);
+void	core_update_lun_access(struct se_lun *, u32);
 struct se_lun_acl *core_dev_init_initiator_node_lun_acl(struct se_portal_group *,
 		struct se_node_acl *, u64, int *);
 int	core_dev_add_initiator_node_lun_acl(struct se_portal_group *,