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>
This commit is contained in:
Wu Fengguang 2009-12-16 12:19:59 +01:00 committed by Andi Kleen
parent 138ce286eb
commit 7c116f2b0d
4 changed files with 72 additions and 0 deletions

View file

@ -115,6 +115,13 @@ memory failures.
Note these injection interfaces are not stable and might change between
kernel versions
corrupt-filter-dev-major
corrupt-filter-dev-minor
Only handle memory failures to pages associated with the file system defined
by block device major/minor. -1U is the wildcard value.
This should be only used for testing with artificial injection.
Architecture specific MCE injector
x86 has mce-inject, mce-test

View file

@ -3,6 +3,7 @@
#include <linux/debugfs.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include "internal.h"
static struct dentry *hwpoison_dir;
@ -54,6 +55,16 @@ 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();

View file

@ -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;

View file

@ -48,6 +48,50 @@ int sysctl_memory_failure_recovery __read_mostly = 1;
atomic_long_t mce_bad_pages __read_mostly = ATOMIC_LONG_INIT(0);
u32 hwpoison_filter_dev_major = ~0U;
u32 hwpoison_filter_dev_minor = ~0U;
EXPORT_SYMBOL_GPL(hwpoison_filter_dev_major);
EXPORT_SYMBOL_GPL(hwpoison_filter_dev_minor);
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;
}
EXPORT_SYMBOL_GPL(hwpoison_filter);
/*
* Send all the processes who have the page mapped an ``action optional''
* signal.
@ -843,6 +887,13 @@ int __memory_failure(unsigned long pfn, int trapno, int flags)
res = 0;
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);