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

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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>
This commit is contained in:
Christophe Vu-Brugier 2015-03-19 14:30:13 +01:00 committed by Nicholas Bellinger
parent 5f7da044f8
commit 9bc6548f37
4 changed files with 17 additions and 18 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
drivers/target/target_core_device.c
View File

@ -650,6 +650,18 @@ static u32 se_dev_align_max_sectors(u32 max_sectors, u32 block_size)
return aligned_max_sectors;
}
bool se_dev_check_wce(struct se_device *dev)
{
bool wce = false;
if (dev->transport->get_write_cache)
wce = dev->transport->get_write_cache(dev);
else if (dev->dev_attrib.emulate_write_cache > 0)
wce = true;
return wce;
}
int se_dev_set_max_unmap_lba_count(
struct se_device *dev,
u32 max_unmap_lba_count)

3
drivers/target/target_core_sbc.c
View File

@ -708,8 +708,7 @@ sbc_check_dpofua(struct se_device *dev, struct se_cmd *cmd, unsigned char *cdb)
}
}
if (cdb[1] & 0x8) {
if (!dev->dev_attrib.emulate_fua_write ||
!dev->dev_attrib.emulate_write_cache) {
if (!dev->dev_attrib.emulate_fua_write || !se_dev_check_wce(dev)) {
pr_err("Got CDB: 0x%02x with FUA bit set, but device"
" does not advertise support for FUA write\n",
cdb[0]);

19
drivers/target/target_core_spc.c
View File

@ -454,19 +454,6 @@ check_scsi_name:
}
EXPORT_SYMBOL(spc_emulate_evpd_83);
static bool
spc_check_dev_wce(struct se_device *dev)
{
bool wce = false;
if (dev->transport->get_write_cache)
wce = dev->transport->get_write_cache(dev);
else if (dev->dev_attrib.emulate_write_cache > 0)
wce = true;
return wce;
}
/* Extended INQUIRY Data VPD Page */
static sense_reason_t
spc_emulate_evpd_86(struct se_cmd *cmd, unsigned char *buf)
@ -490,7 +477,7 @@ spc_emulate_evpd_86(struct se_cmd *cmd, unsigned char *buf)
buf[5] = 0x07;
/* If WriteCache emulation is enabled, set V_SUP */
if (spc_check_dev_wce(dev))
if (se_dev_check_wce(dev))
buf[6] = 0x01;
/* If an LBA map is present set R_SUP */
spin_lock(&cmd->se_dev->t10_alua.lba_map_lock);
@ -897,7 +884,7 @@ static int spc_modesense_caching(struct se_cmd *cmd, u8 pc, u8 *p)
if (pc == 1)
goto out;
if (spc_check_dev_wce(dev))
if (se_dev_check_wce(dev))
p[2] = 0x04; /* Write Cache Enable */
p[12] = 0x20; /* Disabled Read Ahead */
@ -1009,7 +996,7 @@ static sense_reason_t spc_emulate_modesense(struct se_cmd *cmd)
(cmd->se_deve->lun_flags & TRANSPORT_LUNFLAGS_READ_ONLY)))
spc_modesense_write_protect(&buf[length], type);
if ((spc_check_dev_wce(dev)) &&
if ((se_dev_check_wce(dev)) &&
(dev->dev_attrib.emulate_fua_write > 0))
spc_modesense_dpofua(&buf[length], type);

1
include/target/target_core_backend.h
View File

@ -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);