dm: add log writes target
Introduce a new target that is meant for file system developers to test file
system integrity at particular points in the life of a file system. We capture
all write requests and associated data and log them to a separate device
for later replay. There is a userspace utility to do this replay. The
idea behind this is to give file system developers a tool to verify that
the file system is always consistent.
Signed-off-by: Josef Bacik <jbacik@fb.com>
Reviewed-by: Zach Brown <zab@zabbo.net>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
diff --git a/drivers/md/Kconfig b/drivers/md/Kconfig
index 109f9dc..6ddc9834 100644
--- a/drivers/md/Kconfig
+++ b/drivers/md/Kconfig
@@ -443,4 +443,20 @@
If unsure, say N.
+config DM_LOG_WRITES
+ tristate "Log writes target support"
+ depends on BLK_DEV_DM
+ ---help---
+ This device-mapper target takes two devices, one device to use
+ normally, one to log all write operations done to the first device.
+ This is for use by file system developers wishing to verify that
+ their fs is writing a consitent file system at all times by allowing
+ them to replay the log in a variety of ways and to check the
+ contents.
+
+ To compile this code as a module, choose M here: the module will
+ be called dm-log-writes.
+
+ If unsure, say N.
+
endif # MD