dm: add emulated block size target
This new target is similar to the linear target except that it emulates
a smaller logical block size on a device with a larger logical block
size. Its main purpose is to emulate 512 byte sectors on 4K native
disks (i.e. 512e).
See Documentation/admin-guide/device-mapper/dm-ebs.rst for details.
Reviewed-by: Damien Le Moal <DamienLeMoal@wdc.com>
Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Randy Dunlap <rdunlap@infradead.org> [Kconfig fixes]
Signed-off-by: Zheng Bin <zhengbin13@huawei.com> [static fixes]
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
diff --git a/drivers/md/Kconfig b/drivers/md/Kconfig
index 8b0c646..6cb6188 100644
--- a/drivers/md/Kconfig
+++ b/drivers/md/Kconfig
@@ -337,6 +337,14 @@
The writecache target doesn't cache reads because reads are supposed
to be cached in standard RAM.
+config DM_EBS
+ tristate "Emulated block size target (EXPERIMENTAL)"
+ depends on BLK_DEV_DM
+ select DM_BUFIO
+ help
+ dm-ebs emulates smaller logical block size on backing devices
+ with larger ones (e.g. 512 byte sectors on 4K native disks).
+
config DM_ERA
tristate "Era target (EXPERIMENTAL)"
depends on BLK_DEV_DM