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Revision 83193e5ebb0164d612aa620ceab7d3746e80e2a4 authored by Darrick J. Wong on 12 July 2021, 19:58:50 UTC, committed by Darrick J. Wong on 15 July 2021, 16:58:42 UTC 
xfs: correct the narrative around misaligned rtinherit/extszinherit dirs
 
While auditing the realtime growfs code, I realized that the GROWFSRT
ioctl (and by extension xfs_growfs) has always allowed sysadmins to
change the realtime extent size when adding a realtime section to the
filesystem.  Since we also have always allowed sysadmins to set
RTINHERIT and EXTSZINHERIT on directories even if there is no realtime
device, this invalidates the premise laid out in the comments added in
commit 603f000b15f2.

In other words, this is not a case of inadequate metadata validation.
This is a case of nearly forgotten (and apparently untested) but
supported functionality.  Update the comments to reflect what we've
learned, and remove the log message about correcting the misalignment.

Fixes: 603f000b15f2 ("xfs: validate extsz hints against rt extent size when rtinherit is set")
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
1 parent 5838d03
Raw File
test_bitops.c 
// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2020 Intel Corporation
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/init.h>
#include <linux/module.h>
#include <linux/printk.h>

/* a tiny module only meant to test
 *
 *   set/clear_bit
 *   get_count_order/long
 */

/* use an enum because that's the most common BITMAP usage */
enum bitops_fun {
	BITOPS_4 = 4,
	BITOPS_7 = 7,
	BITOPS_11 = 11,
	BITOPS_31 = 31,
	BITOPS_88 = 88,
	BITOPS_LAST = 255,
	BITOPS_LENGTH = 256
};

static DECLARE_BITMAP(g_bitmap, BITOPS_LENGTH);

static unsigned int order_comb[][2] = {
	{0x00000003,  2},
	{0x00000004,  2},
	{0x00001fff, 13},
	{0x00002000, 13},
	{0x50000000, 31},
	{0x80000000, 31},
	{0x80003000, 32},
};

#ifdef CONFIG_64BIT
static unsigned long order_comb_long[][2] = {
	{0x0000000300000000, 34},
	{0x0000000400000000, 34},
	{0x00001fff00000000, 45},
	{0x0000200000000000, 45},
	{0x5000000000000000, 63},
	{0x8000000000000000, 63},
	{0x8000300000000000, 64},
};
#endif

static int __init test_bitops_startup(void)
{
	int i, bit_set;

	pr_info("Starting bitops test\n");
	set_bit(BITOPS_4, g_bitmap);
	set_bit(BITOPS_7, g_bitmap);
	set_bit(BITOPS_11, g_bitmap);
	set_bit(BITOPS_31, g_bitmap);
	set_bit(BITOPS_88, g_bitmap);

	for (i = 0; i < ARRAY_SIZE(order_comb); i++) {
		if (order_comb[i][1] != get_count_order(order_comb[i][0]))
			pr_warn("get_count_order wrong for %x\n",
				       order_comb[i][0]);
	}

	for (i = 0; i < ARRAY_SIZE(order_comb); i++) {
		if (order_comb[i][1] != get_count_order_long(order_comb[i][0]))
			pr_warn("get_count_order_long wrong for %x\n",
				       order_comb[i][0]);
	}

#ifdef CONFIG_64BIT
	for (i = 0; i < ARRAY_SIZE(order_comb_long); i++) {
		if (order_comb_long[i][1] !=
			       get_count_order_long(order_comb_long[i][0]))
			pr_warn("get_count_order_long wrong for %lx\n",
				       order_comb_long[i][0]);
	}
#endif

	barrier();

	clear_bit(BITOPS_4, g_bitmap);
	clear_bit(BITOPS_7, g_bitmap);
	clear_bit(BITOPS_11, g_bitmap);
	clear_bit(BITOPS_31, g_bitmap);
	clear_bit(BITOPS_88, g_bitmap);

	bit_set = find_first_bit(g_bitmap, BITOPS_LAST);
	if (bit_set != BITOPS_LAST)
		pr_err("ERROR: FOUND SET BIT %d\n", bit_set);

	pr_info("Completed bitops test\n");

	return 0;
}

static void __exit test_bitops_unstartup(void)
{
}

module_init(test_bitops_startup);
module_exit(test_bitops_unstartup);

MODULE_AUTHOR("Jesse Brandeburg <jesse.brandeburg@intel.com>, Wei Yang <richard.weiyang@gmail.com>");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Bit testing module");
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