From: Roman Bolshakov r.bolshakov@yadro.com
[ Upstream commit 5676234f20fef02f6ca9bd66c63a8860fce62645 ]
WRITE SAME corrupts data on the block device behind iblock if the command is emulated. The emulation code issues (M - 1) * N times more bios than requested, where M is the number of 512 blocks per real block size and N is the NUMBER OF LOGICAL BLOCKS specified in WRITE SAME command. So, for a device with 4k blocks, 7 * N more LBAs gets written after the requested range.
The issue happens because the number of 512 byte sectors to be written is decreased one by one while the real bios are typically from 1 to 8 512 byte sectors per bio.
Fixes: c66ac9db8d4a ("[SCSI] target: Add LIO target core v4.0.0-rc6") Cc: stable@vger.kernel.org Signed-off-by: Roman Bolshakov r.bolshakov@yadro.com Reviewed-by: Bart Van Assche bvanassche@acm.org Signed-off-by: Martin K. Petersen martin.petersen@oracle.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/target/target_core_iblock.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/target/target_core_iblock.c b/drivers/target/target_core_iblock.c index 1bc9b14236d8b..854b2bcca7c1a 100644 --- a/drivers/target/target_core_iblock.c +++ b/drivers/target/target_core_iblock.c @@ -515,7 +515,7 @@ iblock_execute_write_same(struct se_cmd *cmd)
/* Always in 512 byte units for Linux/Block */ block_lba += sg->length >> SECTOR_SHIFT; - sectors -= 1; + sectors -= sg->length >> SECTOR_SHIFT; }
iblock_submit_bios(&list);