https://github.com/torvalds/linux
Revision b928095b0a7cff7fb9fcf4c706348ceb8ab2c295 authored by Miklos Szeredi on 24 September 2014, 15:56:17 UTC, committed by Al Viro on 27 September 2014, 01:16:42 UTC
If overwriting an empty directory with rename, then need to drop the extra nlink. Test prog: #include <stdio.h> #include <fcntl.h> #include <err.h> #include <sys/stat.h> int main(void) { const char *test_dir1 = "test-dir1"; const char *test_dir2 = "test-dir2"; int res; int fd; struct stat statbuf; res = mkdir(test_dir1, 0777); if (res == -1) err(1, "mkdir(\"%s\")", test_dir1); res = mkdir(test_dir2, 0777); if (res == -1) err(1, "mkdir(\"%s\")", test_dir2); fd = open(test_dir2, O_RDONLY); if (fd == -1) err(1, "open(\"%s\")", test_dir2); res = rename(test_dir1, test_dir2); if (res == -1) err(1, "rename(\"%s\", \"%s\")", test_dir1, test_dir2); res = fstat(fd, &statbuf); if (res == -1) err(1, "fstat(%i)", fd); if (statbuf.st_nlink != 0) { fprintf(stderr, "nlink is %lu, should be 0\n", statbuf.st_nlink); return 1; } return 0; } Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Cc: stable@vger.kernel.org Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
1 parent 0f33be0
Tip revision: b928095b0a7cff7fb9fcf4c706348ceb8ab2c295 authored by Miklos Szeredi on 24 September 2014, 15:56:17 UTC
shmem: fix nlink for rename overwrite directory
shmem: fix nlink for rename overwrite directory
Tip revision: b928095
hwpoison-inject.c
/* Inject a hwpoison memory failure on a arbitrary pfn */
#include <linux/module.h>
#include <linux/debugfs.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/swap.h>
#include <linux/pagemap.h>
#include <linux/hugetlb.h>
#include "internal.h"
static struct dentry *hwpoison_dir;
static int hwpoison_inject(void *data, u64 val)
{
unsigned long pfn = val;
struct page *p;
struct page *hpage;
int err;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
if (!pfn_valid(pfn))
return -ENXIO;
p = pfn_to_page(pfn);
hpage = compound_head(p);
/*
* This implies unable to support free buddy pages.
*/
if (!get_page_unless_zero(hpage))
return 0;
if (!hwpoison_filter_enable)
goto inject;
if (!PageLRU(p) && !PageHuge(p))
shake_page(p, 0);
/*
* This implies unable to support non-LRU pages.
*/
if (!PageLRU(p) && !PageHuge(p))
return 0;
/*
* do a racy check with elevated page count, to make sure PG_hwpoison
* will only be set for the targeted owner (or on a free page).
* We temporarily take page lock for try_get_mem_cgroup_from_page().
* memory_failure() will redo the check reliably inside page lock.
*/
lock_page(hpage);
err = hwpoison_filter(hpage);
unlock_page(hpage);
if (err)
return 0;
inject:
pr_info("Injecting memory failure at pfn %#lx\n", pfn);
return memory_failure(pfn, 18, MF_COUNT_INCREASED);
}
static int hwpoison_unpoison(void *data, u64 val)
{
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
return unpoison_memory(val);
}
DEFINE_SIMPLE_ATTRIBUTE(hwpoison_fops, NULL, hwpoison_inject, "%lli\n");
DEFINE_SIMPLE_ATTRIBUTE(unpoison_fops, NULL, hwpoison_unpoison, "%lli\n");
static void pfn_inject_exit(void)
{
debugfs_remove_recursive(hwpoison_dir);
}
static int pfn_inject_init(void)
{
struct dentry *dentry;
hwpoison_dir = debugfs_create_dir("hwpoison", NULL);
if (hwpoison_dir == NULL)
return -ENOMEM;
/*
* Note that the below poison/unpoison interfaces do not involve
* hardware status change, hence do not require hardware support.
* They are mainly for testing hwpoison in software level.
*/
dentry = debugfs_create_file("corrupt-pfn", 0200, hwpoison_dir,
NULL, &hwpoison_fops);
if (!dentry)
goto fail;
dentry = debugfs_create_file("unpoison-pfn", 0200, hwpoison_dir,
NULL, &unpoison_fops);
if (!dentry)
goto fail;
dentry = debugfs_create_u32("corrupt-filter-enable", 0600,
hwpoison_dir, &hwpoison_filter_enable);
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;
dentry = debugfs_create_u64("corrupt-filter-flags-mask", 0600,
hwpoison_dir, &hwpoison_filter_flags_mask);
if (!dentry)
goto fail;
dentry = debugfs_create_u64("corrupt-filter-flags-value", 0600,
hwpoison_dir, &hwpoison_filter_flags_value);
if (!dentry)
goto fail;
#ifdef CONFIG_MEMCG_SWAP
dentry = debugfs_create_u64("corrupt-filter-memcg", 0600,
hwpoison_dir, &hwpoison_filter_memcg);
if (!dentry)
goto fail;
#endif
return 0;
fail:
pfn_inject_exit();
return -ENOMEM;
}
module_init(pfn_inject_init);
module_exit(pfn_inject_exit);
MODULE_LICENSE("GPL");
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