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
debug-pagealloc.c
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/highmem.h>
#include <linux/page-debug-flags.h>
#include <linux/poison.h>
#include <linux/ratelimit.h>
static inline void set_page_poison(struct page *page)
{
__set_bit(PAGE_DEBUG_FLAG_POISON, &page->debug_flags);
}
static inline void clear_page_poison(struct page *page)
{
__clear_bit(PAGE_DEBUG_FLAG_POISON, &page->debug_flags);
}
static inline bool page_poison(struct page *page)
{
return test_bit(PAGE_DEBUG_FLAG_POISON, &page->debug_flags);
}
static void poison_page(struct page *page)
{
void *addr = kmap_atomic(page);
set_page_poison(page);
memset(addr, PAGE_POISON, PAGE_SIZE);
kunmap_atomic(addr);
}
static void poison_pages(struct page *page, int n)
{
int i;
for (i = 0; i < n; i++)
poison_page(page + i);
}
static bool single_bit_flip(unsigned char a, unsigned char b)
{
unsigned char error = a ^ b;
return error && !(error & (error - 1));
}
static void check_poison_mem(unsigned char *mem, size_t bytes)
{
static DEFINE_RATELIMIT_STATE(ratelimit, 5 * HZ, 10);
unsigned char *start;
unsigned char *end;
start = memchr_inv(mem, PAGE_POISON, bytes);
if (!start)
return;
for (end = mem + bytes - 1; end > start; end--) {
if (*end != PAGE_POISON)
break;
}
if (!__ratelimit(&ratelimit))
return;
else if (start == end && single_bit_flip(*start, PAGE_POISON))
printk(KERN_ERR "pagealloc: single bit error\n");
else
printk(KERN_ERR "pagealloc: memory corruption\n");
print_hex_dump(KERN_ERR, "", DUMP_PREFIX_ADDRESS, 16, 1, start,
end - start + 1, 1);
dump_stack();
}
static void unpoison_page(struct page *page)
{
void *addr;
if (!page_poison(page))
return;
addr = kmap_atomic(page);
check_poison_mem(addr, PAGE_SIZE);
clear_page_poison(page);
kunmap_atomic(addr);
}
static void unpoison_pages(struct page *page, int n)
{
int i;
for (i = 0; i < n; i++)
unpoison_page(page + i);
}
void kernel_map_pages(struct page *page, int numpages, int enable)
{
if (enable)
unpoison_pages(page, numpages);
else
poison_pages(page, numpages);
}
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