On 06/23/2015 04:09 AM, Jan Kara wrote: >> @@ -1340,7 +1344,7 @@ int freeze_super(struct super_block *sb) >> printk(KERN_ERR >> "VFS:Filesystem freeze failed\n"); >> sb->s_writers.frozen = SB_UNFROZEN; >> - smp_wmb(); >> + synchronize_rcu(); > > Do we really need synchronize_rcu() here? We just need to make sure write > to sb->s_writers.frozen happens before we start waking processes...
I don't think it is necessary. We only need to be concerned in practice if someone could be inside a critical section when we are executing this. I *think* the only case that we have that really matters will be taken care of by the _first_ synchronize_rcu(). It's definitely worth adding a comment. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
