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
CC: Haicheng Li <haicheng.li@xxxxxxxxx>
CC: Nick Piggin <npiggin@xxxxxxx>
CC: Andi Kleen <andi@xxxxxxxxxxxxxx>
Signed-off-by: Wu Fengguang <fengguang.wu@xxxxxxxxx>
---
mm/hwpoison-inject.c | 11 +++++++++
mm/internal.h | 3 ++
mm/memory-failure.c | 48 +++++++++++++++++++++++++++++++++++++++++
3 files changed, 62 insertions(+)
--- linux-mm.orig/mm/memory-failure.c 2009-11-30 20:44:31.000000000 +0800
+++ linux-mm/mm/memory-failure.c 2009-11-30 20:51:22.000000000 +0800
@@ -48,6 +48,47 @@ int sysctl_memory_failure_recovery __rea
atomic_long_t mce_bad_pages __read_mostly = ATOMIC_LONG_INIT(0);
+u32 hwpoison_filter_dev_major = ~0U;
+u32 hwpoison_filter_dev_minor = ~0U;
+
+static int hwpoison_filter_dev(struct page *p)
+{
+ struct address_space *mapping;
+ dev_t dev;
+
+ if (hwpoison_filter_dev_major == ~0U &&
+ hwpoison_filter_dev_minor == ~0U)
+ return 0;
+
+ /*
+ * page_mapping() does not accept slab page
+ */
+ if (PageSlab(p))
+ return -EINVAL;
+
+ mapping = page_mapping(p);
+ if (mapping == NULL || mapping->host == NULL)
+ return -EINVAL;
+
+ dev = mapping->host->i_sb->s_dev;
+ if (hwpoison_filter_dev_major != ~0U &&
+ hwpoison_filter_dev_major != MAJOR(dev))
+ return -EINVAL;
+ if (hwpoison_filter_dev_minor != ~0U &&
+ hwpoison_filter_dev_minor != MINOR(dev))
+ return -EINVAL;
+
+ return 0;
+}
+
+int hwpoison_filter(struct page *p)
+{
+ if (hwpoison_filter_dev(p))
+ return -EINVAL;
+
+ return 0;
+}
+
/*
* Send all the processes who have the page mapped an ``action optional''
* signal.
@@ -849,6 +890,13 @@ int __memory_failure(unsigned long pfn,
action_result(&hpc, "unpoisoned", IGNORED);
goto out;
}
+ if (hwpoison_filter(p)) {
+ if (TestClearPageHWPoison(p))
+ atomic_long_dec(&mce_bad_pages);
+ unlock_page(p);
+ put_page(p);
+ return 0;
+ }
wait_on_page_writeback(p);
--- linux-mm.orig/mm/hwpoison-inject.c 2009-11-30 20:30:55.000000000 +0800
+++ linux-mm/mm/hwpoison-inject.c 2009-11-30 20:44:41.000000000 +0800
@@ -3,6 +3,7 @@
#include <linux/debugfs.h>
#include <linux/kernel.h>
#include <linux/mm.h>
+#include "internal.h"
static struct dentry *hwpoison_dir;
@@ -49,6 +50,16 @@ static int pfn_inject_init(void)
if (!dentry)
goto fail;
+ dentry = debugfs_create_u32("corrupt-filter-dev-major", 0600,
+ hwpoison_dir, &hwpoison_filter_dev_major);
+ if (!dentry)
+ goto fail;
+
+ dentry = debugfs_create_u32("corrupt-filter-dev-minor", 0600,
+ hwpoison_dir, &hwpoison_filter_dev_minor);
+ if (!dentry)
+ goto fail;
+
return 0;
fail:
pfn_inject_exit();
--- linux-mm.orig/mm/internal.h 2009-11-30 20:06:01.000000000 +0800
+++ linux-mm/mm/internal.h 2009-11-30 20:44:41.000000000 +0800
@@ -263,3 +263,6 @@ int __get_user_pages(struct task_struct
#define ZONE_RECLAIM_SOME 0
#define ZONE_RECLAIM_SUCCESS 1
#endif
+
+extern u32 hwpoison_filter_dev_major;
+extern u32 hwpoison_filter_dev_minor;
--
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