Messages in this thread | | | Date | Mon, 16 Feb 2009 10:47:02 +0800 | From | Li Zefan <> | Subject | Re: [cgroup or VFS ?] WARNING: at fs/namespace.c:636 mntput_no_expire+0xac/0xf2() |
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> OK... So here's what we really want: > * we know that nobody will set cpu_writer->mnt to mnt from now on > * all changes to that sucker are done under cpu_writer->lock > * we want the laziest equivalent of > spin_lock(&cpu_writer->lock); > if (likely(cpu_writer->mnt != mnt)) { > spin_unlock(&cpu_writer->lock); > continue; > } > /* do stuff */ > that would make sure we won't miss earlier setting of ->mnt done by another > CPU. >
If this is done, I'll be available to test it.
> Anyway, for now (HEAD and all -stable starting with 2.6.26) we want this: >
And here is my:
Tested-by: Li Zefan <lizf@cn.fujitsu.com>
> --- fs/namespace.c 2009-01-25 21:45:31.000000000 -0500 > +++ fs/namespace.c 2009-02-15 21:31:14.000000000 -0500 > @@ -614,9 +614,11 @@ > */ > for_each_possible_cpu(cpu) { > struct mnt_writer *cpu_writer = &per_cpu(mnt_writers, cpu); > - if (cpu_writer->mnt != mnt) > - continue; > spin_lock(&cpu_writer->lock); > + if (cpu_writer->mnt != mnt) { > + spin_unlock(&cpu_writer->lock); > + continue; > + } > atomic_add(cpu_writer->count, &mnt->__mnt_writers); > cpu_writer->count = 0; > /*
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