From: Dave Chinner <dchinner@redhat.com>
Date: Mon, 8 Nov 2010 08:55:04 +0000 (+0000)
Subject: xfs: fix per-ag reference counting in inode reclaim tree walking
X-Git-Tag: firefly_0821_release~7613^2~3456^2~5
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=f83282a8ef799c0bdcb0c32971487087da1bc216;p=firefly-linux-kernel-4.4.55.git

xfs: fix per-ag reference counting in inode reclaim tree walking

The walk fails to decrement the per-ag reference count when the
non-blocking walk fails to obtain the per-ag reclaim lock, leading
to an assert failure on debug kernels when unmounting a filesystem.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Alex Elder <aelder@sgi.com>
---

diff --git a/fs/xfs/linux-2.6/xfs_sync.c b/fs/xfs/linux-2.6/xfs_sync.c
index 37d33254981d..afb0d7cfad1c 100644
--- a/fs/xfs/linux-2.6/xfs_sync.c
+++ b/fs/xfs/linux-2.6/xfs_sync.c
@@ -853,6 +853,7 @@ restart:
 		if (trylock) {
 			if (!mutex_trylock(&pag->pag_ici_reclaim_lock)) {
 				skipped++;
+				xfs_perag_put(pag);
 				continue;
 			}
 			first_index = pag->pag_ici_reclaim_cursor;
diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c
index b1498ab5a399..19e9dfa1c254 100644
--- a/fs/xfs/xfs_mount.c
+++ b/fs/xfs/xfs_mount.c
@@ -275,6 +275,7 @@ xfs_free_perag(
 		pag = radix_tree_delete(&mp->m_perag_tree, agno);
 		spin_unlock(&mp->m_perag_lock);
 		ASSERT(pag);
+		ASSERT(atomic_read(&pag->pag_ref) == 0);
 		call_rcu(&pag->rcu_head, __xfs_free_perag);
 	}
 }