[Ocfs2-devel] [PATCH] ocfs2: fix possible double free in ocfs2_write_begin_nolock
Joel Becker
jlbec at evilplan.org
Thu Nov 7 03:11:53 PST 2013
On Sat, Oct 26, 2013 at 05:09:52PM +0800, Xue jiufei wrote:
> When ocfs2_write_cluster_by_desc() failed in ocfs2_write_begin_nolock()
> because of ENOSPC, it goes to out_quota, freeing data_ac(meta_ac). Then
> it calls ocfs2_try_to_free_truncate_log() to free space. If enough
> space freed, it will try to write again. Unfortunately, some error
> happenes before ocfs2_lock_allocators(), it goes to out and free
> data_ac(meta_ac) again.
>
> Signed-off-by: joyce <xuejiufei at huawei.com>
Good catch. This function could use some refactoring for
understandability.
Acked-by: Joel Becker <jlbec at evilplan.org>
> ---
> fs/ocfs2/aops.c | 8 ++++++--
> 1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c
> index f37d3c0..8ad0a41 100644
> --- a/fs/ocfs2/aops.c
> +++ b/fs/ocfs2/aops.c
> @@ -1897,10 +1897,14 @@ out_commit:
> out:
> ocfs2_free_write_ctxt(wc);
>
> - if (data_ac)
> + if (data_ac) {
> ocfs2_free_alloc_context(data_ac);
> - if (meta_ac)
> + data_ac = NULL;
> + }
> + if (meta_ac) {
> ocfs2_free_alloc_context(meta_ac);
> + meta_ac = NULL;
> + }
>
> if (ret == -ENOSPC && try_free) {
> /*
> --
> 1.7.9.7
>
>
> _______________________________________________
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> Ocfs2-devel at oss.oracle.com
> https://oss.oracle.com/mailman/listinfo/ocfs2-devel
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