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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
parent1c1c6ebcf5284aee4910f3b906ac90c20e510c82 (diff)
downloadop-kernel-dev-aed3bb90abaf0b42e8c8747e192f7bb97f445279.zip
op-kernel-dev-aed3bb90abaf0b42e8c8747e192f7bb97f445279.tar.gz
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>
-rw-r--r--fs/xfs/xfs_ag.h4
-rw-r--r--fs/xfs/xfs_mount.c1
-rw-r--r--fs/xfs/xfs_mount.h11
3 files changed, 12 insertions, 4 deletions
diff --git a/fs/xfs/xfs_ag.h b/fs/xfs/xfs_ag.h
index 6702bd8..18ae43f 100644
--- a/fs/xfs/xfs_ag.h
+++ b/fs/xfs/xfs_ag.h
@@ -196,8 +196,8 @@ typedef struct xfs_perag_busy {
#define XFS_PAGB_NUM_SLOTS 128
#endif
-typedef struct xfs_perag
-{
+typedef struct xfs_perag {
+ atomic_t pag_ref; /* perag reference count */
char pagf_init; /* this agf's entry is initialized */
char pagi_init; /* this agi's entry is initialized */
char pagf_metadata; /* the agf is preferred to be metadata */
diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c
index c04dd83..f241fec 100644
--- a/fs/xfs/xfs_mount.c
+++ b/fs/xfs/xfs_mount.c
@@ -215,6 +215,7 @@ xfs_free_perag(
for (agno = 0; agno < mp->m_sb.sb_agcount; agno++) {
spin_lock(&mp->m_perag_lock);
pag = radix_tree_delete(&mp->m_perag_tree, agno);
+ ASSERT(atomic_read(&pag->pag_ref) == 0);
spin_unlock(&mp->m_perag_lock);
ASSERT(pag);
kmem_free(pag->pagb_list);
diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h
index cfa7a5d..16b2212 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);
}
/*
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