target: do not reject FUA CDBs when write cache is enabled but emulate_write_cache is 0

A check that rejects a CDB with FUA bit set if no write cache is
emulated was added by the following commit:

  fde9f50 target: Add sanity checks for DPO/FUA bit usage

The condition is as follows:

  if (!dev->dev_attrib.emulate_fua_write ||
      !dev->dev_attrib.emulate_write_cache)

However, this check is wrong if the backend device supports WCE but
"emulate_write_cache" is disabled.

This patch uses se_dev_check_wce() (previously named
spc_check_dev_wce) to invoke transport->get_write_cache() if the
device has a write cache or check the "emulate_write_cache" attribute
otherwise.

Reported-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christophe Vu-Brugier <cvubrugier@fastmail.fm>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/include/target/target_core_backend.h b/include/target/target_core_backend.h
index db81c65b8f48..d61be7297b2c 100644
--- a/include/target/target_core_backend.h
+++ b/include/target/target_core_backend.h
@@ -111,6 +111,7 @@ void	array_free(void *array, int n);
 void    target_core_setup_sub_cits(struct se_subsystem_api *);
 
 /* attribute helpers from target_core_device.c for backend drivers */
+bool    se_dev_check_wce(struct se_device *);
 int     se_dev_set_max_unmap_lba_count(struct se_device *, u32);
 int     se_dev_set_max_unmap_block_desc_count(struct se_device *, u32);
 int     se_dev_set_unmap_granularity(struct se_device *, u32);