Re: [PATCH] fs/autofs: Fix sparse warning: context imbalance in'autofs4_d_automount' - different lock contexts for basic block

From: Ian Kent
Date: Thu Jan 03 2013 - 18:53:57 EST


On Thu, 2013-01-03 at 15:52 +0100, Peter Huewe wrote:
> Sparse complains:
> + fs/autofs4/root.c:409:9: sparse: context imbalance in
> 'autofs4_d_automount' - different lock contexts for basic block
>
> This was introduced by commit
> f55fb0c243 autofs4 - dont clear DCACHE_NEED_AUTOMOUNT on rootless mount
>
> The function autofs4_d_automount can be left with the (&sbi->fs_lock)
> held if sbi->version <= 4 and simple_empty(dentry) == false so the warning seems valid.
>
> --> Add an spin_unlock in this case before we jump to done
>
> Unfortunately compile tested only.
>
> Reported-by: Fengguang Wu <fengguang.wu@xxxxxxxxx>
> Signed-off-by: Peter Huewe <peterhuewe@xxxxxx>

Yes, good catch, it looks right to me.
Acked-by: Ian Kent <raven@xxxxxxxxxx>

> ---
> fs/autofs4/root.c | 4 +++-
> 1 files changed, 3 insertions(+), 1 deletions(-)
>
> diff --git a/fs/autofs4/root.c b/fs/autofs4/root.c
> index c934476..74a299f 100644
> --- a/fs/autofs4/root.c
> +++ b/fs/autofs4/root.c
> @@ -383,8 +383,10 @@ static struct vfsmount *autofs4_d_automount(struct path *path)
> goto done;
> }
> } else {
> - if (!simple_empty(dentry))
> + if (!simple_empty(dentry)) {
> + spin_unlock(&sbi->fs_lock);
> goto done;
> + }
> }
> ino->flags |= AUTOFS_INF_PENDING;
> spin_unlock(&sbi->fs_lock);


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