[PATCH] dm: create error table

Add a library function dm_create_error_table() to create a table that rejects
any I/O sent to a device with EIO.

Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 6 insertions, 0 deletions

diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
index 010c8c5eeb37..61103d2bc244 100644
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -227,5 +227,11 @@ void dm_table_event(struct dm_table *t);
  */
 int dm_swap_table(struct mapped_device *md, struct dm_table *t);
 
+/*
+ * Prepare a table for a device that will error all I/O.
+ * To make it active, call dm_suspend(), dm_swap_table() then dm_resume().
+ */
+int dm_create_error_table(struct dm_table **result, struct mapped_device *md);
+
 #endif  /* __KERNEL__ */
 #endif  /* _LINUX_DEVICE_MAPPER_H */