target: Propigate backend read-only to core_tpg_add_lun

This patch adds a DF_READ_ONLY flag that is used by IBLOCK to
signal when a backend has been set to read-only mode, in order
to propigate read-only status up to core_tpg_add_lun() for all
future LUN fabric exports.

With this is place, existing emulation for reporting read-only
in spc_emulate_modesense() and normal transport_lookup_cmd_lun()
TCM_WRITE_PROTECTED status checking just works as expected.

Reported-by: Joeue Deng <joeue404@gmail.com>
Reported-by: Andy Grover <agrover@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

diff --git a/drivers/target/target_core_iblock.c b/drivers/target/target_core_iblock.c
index 5a9982f..0f19e11 100644 (file)
--- a/drivers/target/target_core_iblock.c
+++ b/drivers/target/target_core_iblock.c
@@ -105,6 +105,8 @@ static int iblock_configure_device(struct se_device *dev)
        mode = FMODE_READ|FMODE_EXCL;
        if (!ib_dev->ibd_readonly)
                mode |= FMODE_WRITE;
+       else
+               dev->dev_flags |= DF_READ_ONLY;
 
        bd = blkdev_get_by_path(ib_dev->ibd_udev_path, mode, ib_dev);
        if (IS_ERR(bd)) {

diff --git a/drivers/target/target_core_tpg.c b/drivers/target/target_core_tpg.c
index 2d0381d..5fb9dd7 100644 (file)
--- a/drivers/target/target_core_tpg.c
+++ b/drivers/target/target_core_tpg.c
@@ -668,7 +668,10 @@ int core_tpg_add_lun(
        list_add_tail(&lun->lun_dev_link, &dev->dev_sep_list);
        spin_unlock(&dev->se_port_lock);
 
-       lun->lun_access = lun_access;
+       if (dev->dev_flags & DF_READ_ONLY)
+               lun->lun_access = TRANSPORT_LUNFLAGS_READ_ONLY;
+       else
+               lun->lun_access = lun_access;
        if (!(dev->se_hba->hba_flags & HBA_FLAGS_INTERNAL_USE))
                hlist_add_head_rcu(&lun->link, &tpg->tpg_lun_hlist);
        mutex_unlock(&tpg->tpg_lun_mutex);

diff --git a/include/target/target_core_base.h b/include/target/target_core_base.h
index ac9bf1c..5f48754 100644 (file)
--- a/include/target/target_core_base.h
+++ b/include/target/target_core_base.h
@@ -730,6 +730,7 @@ struct se_device {
 #define DF_EMULATED_VPD_UNIT_SERIAL            0x00000004
 #define DF_USING_UDEV_PATH                     0x00000008
 #define DF_USING_ALIAS                         0x00000010
+#define DF_READ_ONLY                           0x00000020
        /* Physical device queue depth */
        u32                     queue_depth;
        /* Used for SPC-2 reservations enforce of ISIDs */