Skip to main content

Browse the archive

https://github.com/torvalds/linux
23 October 2021, 00:29:24 UTC
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 
shmem: fix nlink for rename overwrite directory
 
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
Raw File
Tip revision: b928095b0a7cff7fb9fcf4c706348ceb8ab2c295 authored by Miklos Szeredi on 24 September 2014, 15:56:17 UTC
shmem: fix nlink for rename overwrite directory
Tip revision: b928095
mmu_context.c 
/* Copyright (C) 2009 Red Hat, Inc.
 *
 * See ../COPYING for licensing terms.
 */

#include <linux/mm.h>
#include <linux/mmu_context.h>
#include <linux/export.h>
#include <linux/sched.h>

#include <asm/mmu_context.h>

/*
 * use_mm
 *	Makes the calling kernel thread take on the specified
 *	mm context.
 *	(Note: this routine is intended to be called only
 *	from a kernel thread context)
 */
void use_mm(struct mm_struct *mm)
{
	struct mm_struct *active_mm;
	struct task_struct *tsk = current;

	task_lock(tsk);
	active_mm = tsk->active_mm;
	if (active_mm != mm) {
		atomic_inc(&mm->mm_count);
		tsk->active_mm = mm;
	}
	tsk->mm = mm;
	switch_mm(active_mm, mm, tsk);
	task_unlock(tsk);
#ifdef finish_arch_post_lock_switch
	finish_arch_post_lock_switch();
#endif

	if (active_mm != mm)
		mmdrop(active_mm);
}
EXPORT_SYMBOL_GPL(use_mm);

/*
 * unuse_mm
 *	Reverses the effect of use_mm, i.e. releases the
 *	specified mm context which was earlier taken on
 *	by the calling kernel thread
 *	(Note: this routine is intended to be called only
 *	from a kernel thread context)
 */
void unuse_mm(struct mm_struct *mm)
{
	struct task_struct *tsk = current;

	task_lock(tsk);
	sync_mm_rss(mm);
	tsk->mm = NULL;
	/* active_mm is still 'mm' */
	enter_lazy_tlb(mm, tsk);
	task_unlock(tsk);
}
EXPORT_SYMBOL_GPL(unuse_mm);
back to top