3.16.75-rc1 review patch. If anyone has any objections, please let me know.
------------------
From: Roman Bolshakov r.bolshakov@yadro.com
commit 5676234f20fef02f6ca9bd66c63a8860fce62645 upstream.
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") 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 [bwh: Backported to 3.16: use IBLOCK_LBA_SHIFT instead of SECTOR_SHIFT] Signed-off-by: Ben Hutchings ben@decadent.org.uk --- drivers/target/target_core_iblock.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/target/target_core_iblock.c +++ b/drivers/target/target_core_iblock.c @@ -490,7 +490,7 @@ iblock_execute_write_same(struct se_cmd
/* Always in 512 byte units for Linux/Block */ block_lba += sg->length >> IBLOCK_LBA_SHIFT; - sectors -= 1; + sectors -= sg->length >> IBLOCK_LBA_SHIFT; }
iblock_submit_bios(&list, WRITE);