Re: [RFC] pnfsd: Return all ROC layouts On Close

[Benny Halevy <benny@tonian.com>]

On 2011-06-10 19:00, Boaz Harrosh wrote:
> On 06/10/2011 12:56 PM, Benny Halevy wrote:
>> On 2011-05-30 13:27, Benny Halevy wrote:
>>> On 2011-05-30 18:30, Boaz Harrosh wrote:
>>>>
>>>> As talk to with Trond, when a client has sent an nfs4_close, the
>>>> server can surly assume that the given client has already forgotten
>>>> all it's ROC given layouts. And in fact the current Linux-client goes
>>>> to grate length to make sure all ROC layouts are invalidated, before
>>>> sending the close. If a new open+IO comes in and tries to get a new layout,
>>>> it will wait for the nfs4_close to return before sending the new layout_get.
>>>>
>>>> So in light of above the server should simulate layout_return and remove
>>>> any layouts marked ROC on nfs4_close.
>>>>
>>>> Current code is protocol correct, but a more fine-grained approach can be
>>>> devised to also release layouts in open_downgrade, of all unused iomodes.
>>>> But to do this I'll need the help of an expert.
>>>>
>>>> With this patch in, I'm finally able to run with the new Linux-Client together
>>>> with a Linux-Server. Before, the layouts where only released and freed on umount
>>>> and in a modest machine like the UML I use, few 10s of "git checkout linux" the
>>>> server would oom.
>>>>
>>>> Benny please submit it to the pnfs tree, so we can run with this in Bakeathone.
>>>>
>>>> So please all help me to verify and refine this code.
>>>>
>>>> Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
>>>> ---
>>>>  fs/nfsd/nfs4pnfsd.c |   44 ++++++++++++++++++++++++++++++++++++++++++--
>>>>  fs/nfsd/nfs4state.c |    3 +++
>>>>  fs/nfsd/pnfsd.h     |    3 +++
>>>>  3 files changed, 48 insertions(+), 2 deletions(-)
>>>>
>>>> diff --git a/fs/nfsd/nfs4pnfsd.c b/fs/nfsd/nfs4pnfsd.c
>>>> index 9089e6b9..d8f744e 100644
>>>> --- a/fs/nfsd/nfs4pnfsd.c
>>>> +++ b/fs/nfsd/nfs4pnfsd.c
>>>> @@ -402,7 +402,8 @@ init_layout(struct nfs4_layout_state *ls,
>>>>  	    struct nfs4_client *clp,
>>>>  	    struct svc_fh *current_fh,
>>>>  	    struct nfsd4_layout_seg *seg,
>>>> -	    stateid_t *stateid)
>>>> +	    stateid_t *stateid,
>>>> +	    bool roc)
>>>>  {
>>>>  	dprintk("pNFS %s: ls %p lp %p clp %p fp %p ino %p\n", __func__,
>>>>  		ls, lp, clp, fp, fp->fi_inode);
>>>> @@ -412,6 +413,7 @@ init_layout(struct nfs4_layout_state *ls,
>>>>  	lp->lo_file = fp;
>>>>  	get_layout_state(ls);
>>>>  	lp->lo_state = ls;
>>>> +	lp->lo_roc = roc;
>>>>  	memcpy(&lp->lo_seg, seg, sizeof(lp->lo_seg));
>>>>  	spin_lock(&layout_lock);
>>>>  	update_layout_stateid(ls, stateid);
>>>> @@ -914,7 +916,8 @@ nfs4_pnfs_get_layout(struct nfsd4_pnfs_layoutget *lgp,
>>>>  		goto out_freelayout;
>>>>  
>>>>  	/* Can't merge, so let's initialize this new layout */
>>>> -	init_layout(ls, lp, fp, clp, lgp->lg_fhp, &res.lg_seg, &lgp->lg_sid);
>>>> +	init_layout(ls, lp, fp, clp, lgp->lg_fhp, &res.lg_seg, &lgp->lg_sid,
>>>> +		    res.lg_return_on_close);
>>>>  out_unlock:
>>>>  	if (ls)
>>>>  		put_layout_state(ls);
>>>> @@ -1328,6 +1331,43 @@ nomatching_layout(struct nfs4_layoutrecall *clr)
>>>>  	iput(inode);
>>>>  }
>>>>  
>>>> +/* Return On Close:
>>>> + *   Look for all layouts of @fp that belong to @clp, if ROC is set, remove
>>>> + *   the layout and simulate a layout_return. Surly the client has forgotten
>>>> + *   these layouts or it would return them before the close.
>>>> + */
>>>> +void pnfs_roc(struct nfs4_client *clp, struct nfs4_file *fp,
>>>> +	      enum pnfs_iomode iomode)
>>>
>>> what's the iomode for?
>>>
>>> The nfs CLOSE operation is sent on the final close on the client side.
>>> otherwise you'd get an OPEN_DOWNGRADE for which return on close is not
>>> really defined.
>>
>> Ping... :)
>>
>> Benny
>>
> 
> Fine just drop the iomode param for now. But with out this patch I cannot
> run

Sure, no problem....

> 
> Boaz
> 
>>>
>>> Benny
>>>
>>>> +{
>>>> +	struct nfs4_layout *lo, *nextlp;
>>>> +
>>>> +	spin_lock(&layout_lock);
>>>> +	list_for_each_entry_safe (lo, nextlp, &fp->fi_layouts, lo_perfile) {
>>>> +		struct nfsd4_pnfs_layoutreturn lr;
>>>> +		bool empty;
>>>> +
>>>> +		/* Check for a match */
>>>> +		if (!lo->lo_roc ||
>>>> +		    (lo->lo_client != clp) ||
>>>> +		    ((iomode != IOMODE_ANY) && (lo->lo_seg.iomode != iomode))
>>>> +		)
>>>> +			continue;
>>>> +
>>>> +		/* Return the layout */
>>>> +		memset(&lr, 0, sizeof(lr));
>>>> +		lr.args.lr_return_type = RETURN_FILE;
>>>> +		lr.args.lr_seg = lo->lo_seg;
>>>> +		dequeue_layout(lo);
>>>> +		destroy_layout(lo); /* do not access lp after this */
>>>> +
>>>> +		empty = list_empty(&fp->fi_layouts);
>>>> +		fs_layout_return(fp->fi_inode->i_sb, fp->fi_inode, &lr,
>>>> +				 LR_FLAG_EXPIRE,
>>>> +				 empty ? PNFS_LAST_LAYOUT_NO_RECALLS : NULL);
>>>> +	}
>>>> +	spin_unlock(&layout_lock);
>>>> +}
>>>> +
>>>>  void pnfs_expire_client(struct nfs4_client *clp)
>>>>  {
>>>>  	for (;;) {
>>>> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
>>>> index 66f6f48..a116e41 100644
>>>> --- a/fs/nfsd/nfs4state.c
>>>> +++ b/fs/nfsd/nfs4state.c
>>>> @@ -3592,6 +3592,9 @@ nfsd4_close(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
>>>>  	/* release_stateid() calls nfsd_close() if needed */
>>>>  	release_open_stateid(stp);
>>>>  
>>>> +	/* RFC: what to do with IOMODE */
>>>> +	pnfs_roc(stp->st_stateowner->so_client, stp->st_file, IOMODE_ANY);
>>>> +
>>>>  	/* place unused nfs4_stateowners on so_close_lru list to be
>>>>  	 * released by the laundromat service after the lease period
>>>>  	 * to enable us to handle CLOSE replay
>>>> diff --git a/fs/nfsd/pnfsd.h b/fs/nfsd/pnfsd.h
>>>> index c11d93d..fcb16d2 100644
>>>> --- a/fs/nfsd/pnfsd.h
>>>> +++ b/fs/nfsd/pnfsd.h
>>>> @@ -59,6 +59,7 @@ struct nfs4_layout {
>>>>  	struct nfs4_client		*lo_client;
>>>>  	struct nfs4_layout_state	*lo_state;
>>>>  	struct nfsd4_layout_seg 	lo_seg;
>>>> +	bool				lo_roc;
>>>>  };
>>>>  
>>>>  struct pnfs_inval_state {
>>>> @@ -124,6 +125,8 @@ int nfs4_pnfs_cb_change_state(struct pnfs_get_state *);
>>>>  void nfs4_ds_get_verifier(stateid_t *, struct super_block *, u32 *);
>>>>  int put_layoutrecall(struct nfs4_layoutrecall *);
>>>>  void nomatching_layout(struct nfs4_layoutrecall *);
>>>> +void pnfs_roc(struct nfs4_client *clp, struct nfs4_file *fp,
>>>> +	      enum pnfs_iomode iomode);
>>>>  void *layoutrecall_done(struct nfs4_layoutrecall *);
>>>>  void nfsd4_cb_layout(struct nfs4_layoutrecall *);
>>>>  int nfsd_layout_recall_cb(struct super_block *, struct inode *,
>>>
> 
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