From: Will Deacon <will.deacon@arm.com>
To: linux-fsdevel@vger.kernel.org
Cc: peterz@infradead.org, viro@zeniv.linux.org.uk,
willy@infradead.org, linux-kernel@vger.kernel.org,
Will Deacon <will.deacon@arm.com>
Subject: [PATCH v2 2/2] fs: dcache: Use READ_ONCE when accessing i_dir_seq
Date: Mon, 19 Feb 2018 14:55:55 +0000 [thread overview]
Message-ID: <1519052155-6361-3-git-send-email-will.deacon@arm.com> (raw)
In-Reply-To: <1519052155-6361-1-git-send-email-will.deacon@arm.com>
i_dir_seq is subject to concurrent modification by a cmpxchg or
store-release operation, so ensure that the relaxed access in
d_alloc_parallel uses READ_ONCE.
Reported-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
---
fs/dcache.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/dcache.c b/fs/dcache.c
index b243deec298c..5716ab04e1db 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -2502,7 +2502,7 @@ struct dentry *d_alloc_parallel(struct dentry *parent,
}
hlist_bl_lock(b);
- if (unlikely(parent->d_inode->i_dir_seq != seq)) {
+ if (unlikely(READ_ONCE(parent->d_inode->i_dir_seq) != seq)) {
hlist_bl_unlock(b);
rcu_read_unlock();
goto retry;
--
2.1.4
next prev parent reply other threads:[~2018-02-19 14:55 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-19 14:55 [PATCH v2 0/2] A couple of i_dir_seq fixes for fs/dcache.c Will Deacon
2018-02-19 14:55 ` [PATCH v2 1/2] fs: dcache: Avoid livelock between d_alloc_parallel and __d_add Will Deacon
2018-02-19 14:55 ` Will Deacon [this message]
2018-02-26 18:05 ` [PATCH v2 0/2] A couple of i_dir_seq fixes for fs/dcache.c Will Deacon
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