Commit 4d8f4246 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Carlos Maiolino
Browse files

xfs: use WRITE_ONCE/READ_ONCE for m_errortag 



There is no synchronization for updating m_errortag, which is fine as
it's just a debug tool.  It would still be nice to fully avoid the
theoretical case of torn values, so use WRITE_ONCE and READ_ONCE to
access the members.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarHans Holmberg <hans.holmberg@wdc.com>
Reviewed-by: default avatarCarlos Maiolino <cmaiolino@redhat.com>
Reviewed-by: default avatarDarrick J. Wong <djwong@kernel.org>
Signed-off-by: default avatarCarlos Maiolino <cem@kernel.org>
parent e2d62bfd

fs/xfs/xfs_error.c

+14 −9
Original line number Diff line number Diff line
@@ -50,17 +50,18 @@ xfs_errortag_attr_store( 
{

	struct xfs_mount	*mp = to_mp(kobject);

	unsigned int		error_tag = to_attr(attr)->tag;

	unsigned int		val;

	int			ret;



	if (strcmp(buf, "default") == 0) {

		mp->m_errortag[error_tag] =

			xfs_errortag_random_default[error_tag];

		val = xfs_errortag_random_default[error_tag];

	} else {

		ret = kstrtouint(buf, 0, &mp->m_errortag[error_tag]);

		ret = kstrtouint(buf, 0, &val);

		if (ret)

			return ret;

	}



	WRITE_ONCE(mp->m_errortag[error_tag], val);

	return count;

}
@@ -71,9 +72,9 @@ xfs_errortag_attr_show( 
	char			*buf)

{

	struct xfs_mount	*mp = to_mp(kobject);

	unsigned int		error_tag = to_attr(attr)->tag;



	return snprintf(buf, PAGE_SIZE, "%u\n", mp->m_errortag[error_tag]);

	return snprintf(buf, PAGE_SIZE, "%u\n",

			READ_ONCE(mp->m_errortag[to_attr(attr)->tag]));

}



static const struct sysfs_ops xfs_errortag_sysfs_ops = {
@@ -134,7 +135,7 @@ xfs_errortag_test( 
{

	unsigned int		randfactor;



	randfactor = mp->m_errortag[error_tag];

	randfactor = READ_ONCE(mp->m_errortag[error_tag]);

	if (!randfactor || get_random_u32_below(randfactor))

		return false;
@@ -151,7 +152,7 @@ xfs_errortag_delay( 
	int			line,

	unsigned int		error_tag)

{

	unsigned int		delay = mp->m_errortag[error_tag];

	unsigned int		delay = READ_ONCE(mp->m_errortag[error_tag]);



	might_sleep();
@@ -183,7 +184,8 @@ xfs_errortag_add( 
		break;

	}



	mp->m_errortag[error_tag] = xfs_errortag_random_default[error_tag];

	WRITE_ONCE(mp->m_errortag[error_tag],

		   xfs_errortag_random_default[error_tag]);

	return 0;

}
@@ -191,7 +193,10 @@ int 
xfs_errortag_clearall(

	struct xfs_mount	*mp)

{

	memset(mp->m_errortag, 0, sizeof(unsigned int) * XFS_ERRTAG_MAX);

	unsigned int		i;



	for (i = 0; i < XFS_ERRTAG_MAX; i++)

		WRITE_ONCE(mp->m_errortag[i], 0);

	return 0;

}

#endif /* DEBUG */