target: Disallow changing of WRITE cache/FUA attrs after export
Now that incoming FUA=1 bit check is enforced for backends with FUA or
WCE disabled, go ahead and disallow the changing of related backend
attributes when active fabric exports exist.
This is required to avoid potential failures with existing initiator
LUN registrations that have been previously created with FUA=1.
Reported-by: Christoph Hellwig <hch@lst.de>
Cc: Doug Gilbert <dgilbert@interlog.com>
Cc: James Bottomley <JBottomley@Parallels.com>
Cc: Ronnie Sahlberg <ronniesahlberg@gmail.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
diff --git a/drivers/target/target_core_device.c b/drivers/target/target_core_device.c
index 58f49ff..37449bd 100644
--- a/drivers/target/target_core_device.c
+++ b/drivers/target/target_core_device.c
@@ -767,6 +767,16 @@
pr_err("Illegal value %d\n", flag);
return -EINVAL;
}
+ if (flag &&
+ dev->transport->get_write_cache) {
+ pr_err("emulate_fua_write not supported for this device\n");
+ return -EINVAL;
+ }
+ if (dev->export_count) {
+ pr_err("emulate_fua_write cannot be changed with active"
+ " exports: %d\n", dev->export_count);
+ return -EINVAL;
+ }
dev->dev_attrib.emulate_fua_write = flag;
pr_debug("dev[%p]: SE Device Forced Unit Access WRITEs: %d\n",
dev, dev->dev_attrib.emulate_fua_write);
@@ -801,7 +811,11 @@
pr_err("emulate_write_cache not supported for this device\n");
return -EINVAL;
}
-
+ if (dev->export_count) {
+ pr_err("emulate_write_cache cannot be changed with active"
+ " exports: %d\n", dev->export_count);
+ return -EINVAL;
+ }
dev->dev_attrib.emulate_write_cache = flag;
pr_debug("dev[%p]: SE Device WRITE_CACHE_EMULATION flag: %d\n",
dev, dev->dev_attrib.emulate_write_cache);