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authorDave Chinner <david@fromorbit.com>2010-01-11 11:47:45 +0000
committerAlex Elder <aelder@sgi.com>2010-01-15 15:34:04 -0600
commitaed3bb90abaf0b42e8c8747e192f7bb97f445279 (patch)
tree4619214ed42821792b05f4417cb95bde90abb562 /fs/xfs/xfs_mount.h
parent1c1c6ebcf5284aee4910f3b906ac90c20e510c82 (diff)
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 <david@fromorbit.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Alex Elder <aelder@sgi.com>
Diffstat (limited to 'fs/xfs/xfs_mount.h')
-rw-r--r--fs/xfs/xfs_mount.h11
1 files changed, 9 insertions, 2 deletions
diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h
index cfa7a5d22e7..16b22120b98 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);
}
/*