Re: [PATCH] nfs: fix inifinite loop at nfs4_layoutcommit_release

[Vitaliy Gusev <gusev.vitaliy@nexenta.com>]

>>> Reported-by: Vitaliy Gusev<gusev.vitaliy@nexenta.com>
>>> Signed-off-by: Peng Tao<peng_tao@emc.com>
>>> ---
>>>   fs/nfs/nfs4proc.c |    2 ++
>>>   1 files changed, 2 insertions(+), 0 deletions(-)
>>>
>>> diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
>>> index 8c77039..da7c20c 100644
>>> --- a/fs/nfs/nfs4proc.c
>>> +++ b/fs/nfs/nfs4proc.c
>>> @@ -5964,6 +5964,7 @@ static void nfs4_layoutcommit_release(void
>>> *calldata)
>>>         struct pnfs_layout_segment *lseg, *tmp;
>>>
>>>         pnfs_cleanup_layoutcommit(data);
>>> +       spin_lock(&data->args.inode->i_lock);
>>
>> I think lock over list_del_init(&lseg->pls_lc_list) is enough, because
> I put the spinlock outside of the loop because the critical section is
> short enough and it should be faster than grabbing/dropping the inode
> lock for every entry in the list, agree?

Yes, you are right.

Looked again I saw that issue is not so bad as seems.
Really, what is result of this issue? Only that lseg is in 
data->lseg_list, but without set NFS_LSEG_LAYOUTCOMMIT. The put_lseg is 
called correctly at nfs4_layoutcommit_release. So there is no any bug.