On Wed 28-05-14 09:52:19, Niu Yawei wrote:
> Remove dqptr_sem to make quota code scalable: Protect the
> Q_GETFMT by dqonoff_mutex instead of dqptr_sem.
I'd make the changelog more verbose. Otherwise the patch looks good to
me. Something like:
dqptr_sem will go away. Protect Q_GETFMT quotactl by dqonoff_mutex instead.
This is also enough to make sure quota info will not go away while we are
looking at it.
Honza
>
> Signed-off-by: Lai Siyao <lai.siyao@xxxxxxxxx>
> Signed-off-by: Niu Yawei <yawei.niu@xxxxxxxxx>
> ---
> fs/quota/quota.c | 6 +++---
> 1 files changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/fs/quota/quota.c b/fs/quota/quota.c
> index 2b363e2..e4851cb 100644
> --- a/fs/quota/quota.c
> +++ b/fs/quota/quota.c
> @@ -79,13 +79,13 @@ static int quota_getfmt(struct super_block *sb, int type, void __user *addr)
> {
> __u32 fmt;
>
> - down_read(&sb_dqopt(sb)->dqptr_sem);
> + mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
> if (!sb_has_quota_active(sb, type)) {
> - up_read(&sb_dqopt(sb)->dqptr_sem);
> + mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
> return -ESRCH;
> }
> fmt = sb_dqopt(sb)->info[type].dqi_format->qf_fmt_id;
> - up_read(&sb_dqopt(sb)->dqptr_sem);
> + mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
> if (copy_to_user(addr, &fmt, sizeof(fmt)))
> return -EFAULT;
> return 0;
> --
> 1.7.1
>
>
--
Jan Kara <jack@xxxxxxx>
SUSE Labs, CR
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