From aed3bb90abaf0b42e8c8747e192f7bb97f445279 Mon Sep 17 00:00:00 2001 From: Dave Chinner Date: Mon, 11 Jan 2010 11:47:45 +0000 Subject: xfs: Reference count per-ag structures Reference count the per-ag structures to ensure that we keep get/put pairs balanced. Assert that the reference counts are zero at unmount time to catch leaks. In future, reference counts will enable us to safely remove perag structures by allowing us to detect when they are no longer in use. Signed-off-by: Dave Chinner Reviewed-by: Christoph Hellwig Signed-off-by: Alex Elder --- fs/xfs/xfs_mount.h | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) (limited to 'fs/xfs/xfs_mount.h') diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h index cfa7a5d22e72..16b22120b98f 100644 --- a/fs/xfs/xfs_mount.h +++ b/fs/xfs/xfs_mount.h @@ -384,7 +384,7 @@ xfs_daddr_to_agbno(struct xfs_mount *mp, xfs_daddr_t d) } /* - * perag get/put wrappers for eventual ref counting + * perag get/put wrappers for ref counting */ static inline struct xfs_perag * xfs_perag_get(struct xfs_mount *mp, xfs_agnumber_t agno) @@ -393,6 +393,12 @@ xfs_perag_get(struct xfs_mount *mp, xfs_agnumber_t agno) spin_lock(&mp->m_perag_lock); pag = radix_tree_lookup(&mp->m_perag_tree, agno); + if (pag) { + ASSERT(atomic_read(&pag->pag_ref) >= 0); + /* catch leaks in the positive direction during testing */ + ASSERT(atomic_read(&pag->pag_ref) < 1000); + atomic_inc(&pag->pag_ref); + } spin_unlock(&mp->m_perag_lock); return pag; } @@ -400,7 +406,8 @@ xfs_perag_get(struct xfs_mount *mp, xfs_agnumber_t agno) static inline void xfs_perag_put(struct xfs_perag *pag) { - /* nothing to see here, move along */ + ASSERT(atomic_read(&pag->pag_ref) > 0); + atomic_dec(&pag->pag_ref); } /* -- cgit v1.2.3