linux-kernel - [PATCH] reiserfs: Fix softlockup while waiting on an inode

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Date:	Thu, 11 Feb 2010 19:35:22 +0100
From:	Frederic Weisbecker <fweisbec@...il.com>
To:	Alexander Beregalov <a.beregalov@...il.com>
Cc:	LKML <linux-kernel@...r.kernel.org>,
	Frederic Weisbecker <fweisbec@...il.com>,
	Christian Kujau <lists@...dbynature.de>,
	Chris Mason <chris.mason@...cle.com>
Subject: [PATCH] reiserfs: Fix softlockup while waiting on an inode

When we wait for an inode through reiserfs_iget(), we hold
the reiserfs lock. And waiting for an inode may imply waiting
for its writeback. But the inode writeback path may also require
the reiserfs lock, which leads to a deadlock.

We just need to release the reiserfs lock from reiserfs_iget()
to fix this.

Reported-by: Alexander Beregalov <a.beregalov@...il.com>
Signed-off-by: Frederic Weisbecker <fweisbec@...il.com>
Cc: Christian Kujau <lists@...dbynature.de>
Cc: Chris Mason <chris.mason@...cle.com>
---
 fs/reiserfs/inode.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/fs/reiserfs/inode.c b/fs/reiserfs/inode.c
index 9087b10..2df0f5c 100644
--- a/fs/reiserfs/inode.c
+++ b/fs/reiserfs/inode.c
@@ -1497,9 +1497,11 @@ struct inode *reiserfs_iget(struct super_block *s, const struct cpu_key *key)
 
 	args.objectid = key->on_disk_key.k_objectid;
 	args.dirid = key->on_disk_key.k_dir_id;
+	reiserfs_write_unlock(s);
 	inode = iget5_locked(s, key->on_disk_key.k_objectid,
 			     reiserfs_find_actor, reiserfs_init_locked_inode,
 			     (void *)(&args));
+	reiserfs_write_lock(s);
 	if (!inode)
 		return ERR_PTR(-ENOMEM);
 
-- 
1.6.2.3

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