HWPOISON: add fs/device filters

Filesystem data/metadata present the most tricky-to-isolate pages.
It requires careful code review and stress testing to get them right.

The fs/device filter helps to target the stress tests to some specific
filesystem pages. The filter condition is block device's major/minor
numbers:
        - corrupt-filter-dev-major
        - corrupt-filter-dev-minor
When specified (non -1), only page cache pages that belong to that
device will be poisoned.

The filters are checked reliably on the locked and refcounted page.

Haicheng: clear PG_hwpoison and drop bad page count if filter not OK
AK: Add documentation

CC: Haicheng Li <haicheng.li@intel.com>
CC: Nick Piggin <npiggin@suse.de>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/mm/internal.h b/mm/internal.h
index 49b2ff776b78..814da335f050 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -250,3 +250,6 @@ int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
 #define ZONE_RECLAIM_SOME       0
 #define ZONE_RECLAIM_SUCCESS    1
 #endif
+
+extern u32 hwpoison_filter_dev_major;
+extern u32 hwpoison_filter_dev_minor;