Commit c29237a6 authored by Darrick J. Wong's avatar Darrick J. Wong
Browse files

xfs: add a lockdep class key for rtgroup inodes 



Add a dynamic lockdep class key for rtgroup inodes.  This will enable
lockdep to deduce inconsistencies in the rtgroup metadata ILOCK locking
order.  Each class can have 8 subclasses, and for now we will only have
2 inodes per group.  This enables rtgroup order and inode order checks
when nesting ILOCKs.

Signed-off-by: default avatarDarrick J. Wong <djwong@kernel.org>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
parent 0e4875b3

fs/xfs/libxfs/xfs_rtgroup.c

+52 −0
Original line number Diff line number Diff line
@@ -198,3 +198,55 @@ xfs_rtgroup_trans_join( 
	if (rtglock_flags & XFS_RTGLOCK_BITMAP)

		xfs_rtbitmap_trans_join(tp);

}



#ifdef CONFIG_PROVE_LOCKING

static struct lock_class_key xfs_rtginode_lock_class;



static int

xfs_rtginode_ilock_cmp_fn(

	const struct lockdep_map	*m1,

	const struct lockdep_map	*m2)

{

	const struct xfs_inode *ip1 =

		container_of(m1, struct xfs_inode, i_lock.dep_map);

	const struct xfs_inode *ip2 =

		container_of(m2, struct xfs_inode, i_lock.dep_map);



	if (ip1->i_projid < ip2->i_projid)

		return -1;

	if (ip1->i_projid > ip2->i_projid)

		return 1;

	return 0;

}



static inline void

xfs_rtginode_ilock_print_fn(

	const struct lockdep_map	*m)

{

	const struct xfs_inode *ip =

		container_of(m, struct xfs_inode, i_lock.dep_map);



	printk(KERN_CONT " rgno=%u", ip->i_projid);

}



/*

 * Most of the time each of the RTG inode locks are only taken one at a time.

 * But when committing deferred ops, more than one of a kind can be taken.

 * However, deferred rt ops will be committed in rgno order so there is no

 * potential for deadlocks.  The code here is needed to tell lockdep about this

 * order.

 */

static inline void

xfs_rtginode_lockdep_setup(

	struct xfs_inode	*ip,

	xfs_rgnumber_t		rgno,

	enum xfs_rtg_inodes	type)

{

	lockdep_set_class_and_subclass(&ip->i_lock, &xfs_rtginode_lock_class,

			type);

	lock_set_cmp_fn(&ip->i_lock, xfs_rtginode_ilock_cmp_fn,

			xfs_rtginode_ilock_print_fn);

}

#else

#define xfs_rtginode_lockdep_setup(ip, rgno, type)	do { } while (0)

#endif /* CONFIG_PROVE_LOCKING */