Message-ID: <535A6DE9.1040109@gmail.com>
Date: Fri, 25 Apr 2014 10:15:05 -0400
From: Anna Schumaker <schumaker.anna@gmail.com>
MIME-Version: 1.0
To: Weston Andros Adamson <dros@primarydata.com>,
        trond.myklebust@primarydata.com
CC: linux-nfs@vger.kernel.org
Subject: Re: [PATCH 15/18 v2] pnfs: support multiple verfs per direct req
References: <1398363328-7100-1-git-send-email-dros@primarydata.com> <1398363328-7100-16-git-send-email-dros@primarydata.com>
In-Reply-To: <1398363328-7100-16-git-send-email-dros@primarydata.com>
Content-Type: text/plain; charset=ISO-8859-1
Sender: linux-nfs-owner@vger.kernel.org

On 04/24/2014 02:15 PM, Weston Andros Adamson wrote:
> Support direct requests that span multiple pnfs data servers by
> comparing nfs_pgio_header->verf to a cached verf in pnfs_commit_bucket.
> Continue to use dreq->verf if the MDS is used / non-pNFS.
>
> Signed-off-by: Weston Andros Adamson <dros@primarydata.com>
> ---
>  fs/nfs/direct.c         | 98 ++++++++++++++++++++++++++++++++++++++++++++++---
>  fs/nfs/nfs4filelayout.c |  6 +++
>  include/linux/nfs.h     |  5 ++-
>  include/linux/nfs_xdr.h |  2 +
>  4 files changed, 105 insertions(+), 6 deletions(-)
>
> diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c
> index 2c0e08f..9349933 100644
> --- a/fs/nfs/direct.c
> +++ b/fs/nfs/direct.c
> @@ -108,6 +108,93 @@ static inline int put_dreq(struct nfs_direct_req *dreq)
>  	return atomic_dec_and_test(&dreq->io_count);
>  }
>  
> +/*
> + * nfs_direct_select_verf - select the right verifier
> + * @dreq - direct request possibly spanning multiple servers
> + * @ds_clp - nfs_client of data server or NULL if MDS / non-pnfs
> + * @ds_idx - index of data server in data server list, only valid if ds_clp set
> + *
> + * returns the correct verifier to use given the role of the server
> + */
> +static struct nfs_writeverf *
> +nfs_direct_select_verf(struct nfs_direct_req *dreq,
> +		       struct nfs_client *ds_clp,
> +		       int ds_idx)
> +{
> +	struct nfs_writeverf *verfp = &dreq->verf;
> +
> +	if (ds_clp) {
> +		/* pNFS is in use, use the DS verf */
> +		if (ds_idx >= 0 && ds_idx < dreq->ds_cinfo.nbuckets)

The struct pnfs_ds_commit_info is empty if CONFIG_NFS_V4_1=n, so this won't compile.

Anna

> +			verfp = &dreq->ds_cinfo.buckets[ds_idx].direct_verf;
> +		else
> +			WARN_ON_ONCE(1);
> +	}
> +	return verfp;
> +}
> +
> +
> +/*
> + * nfs_direct_set_hdr_verf - set the write/commit verifier
> + * @dreq - direct request possibly spanning multiple servers
> + * @hdr - pageio header to validate against previously seen verfs
> + *
> + * Set the server's (MDS or DS) "seen" verifier
> + */
> +static void nfs_direct_set_hdr_verf(struct nfs_direct_req *dreq,
> +				    struct nfs_pgio_header *hdr)
> +{
> +	struct nfs_writeverf *verfp;
> +
> +	verfp = nfs_direct_select_verf(dreq, hdr->data->ds_clp,
> +				      hdr->data->ds_idx);
> +	WARN_ON_ONCE(verfp->committed >= 0);
> +	memcpy(verfp, &hdr->verf, sizeof(struct nfs_writeverf));
> +	WARN_ON_ONCE(verfp->committed < 0);
> +}
> +
> +/*
> + * nfs_direct_cmp_hdr_verf - compare verifier for pgio header
> + * @dreq - direct request possibly spanning multiple servers
> + * @hdr - pageio header to validate against previously seen verf
> + *
> + * set the server's "seen" verf if not initialized.
> + * returns result of comparison between @hdr->verf and the "seen"
> + * verf of the server used by @hdr (DS or MDS)
> + */
> +static int nfs_direct_set_or_cmp_hdr_verf(struct nfs_direct_req *dreq,
> +					  struct nfs_pgio_header *hdr)
> +{
> +	struct nfs_writeverf *verfp;
> +
> +	verfp = nfs_direct_select_verf(dreq, hdr->data->ds_clp,
> +					 hdr->data->ds_idx);
> +	if (verfp->committed < 0) {
> +		nfs_direct_set_hdr_verf(dreq, hdr);
> +		return 0;
> +	}
> +	return memcmp(verfp, &hdr->verf, sizeof(struct nfs_writeverf));
> +}
> +
> +/*
> + * nfs_direct_cmp_commit_data_verf - compare verifier for commit data
> + * @dreq - direct request possibly spanning multiple servers
> + * @data - commit data to validate against previously seen verf
> + *
> + * returns result of comparison between @data->verf and the verf of
> + * the server used by @data (DS or MDS)
> + */
> +static int nfs_direct_cmp_commit_data_verf(struct nfs_direct_req *dreq,
> +					   struct nfs_commit_data *data)
> +{
> +	struct nfs_writeverf *verfp;
> +
> +	verfp = nfs_direct_select_verf(dreq, data->ds_clp,
> +					 data->ds_commit_index);
> +	WARN_ON_ONCE(verfp->committed < 0);
> +	return memcmp(verfp, &data->verf, sizeof(struct nfs_writeverf));
> +}
> +
>  /**
>   * nfs_direct_IO - NFS address space operation for direct I/O
>   * @rw: direction (read or write)
> @@ -168,6 +255,7 @@ static inline struct nfs_direct_req *nfs_direct_req_alloc(void)
>  	kref_get(&dreq->kref);
>  	init_completion(&dreq->completion);
>  	INIT_LIST_HEAD(&dreq->mds_cinfo.list);
> +	dreq->verf.committed = NFS_INVALID_STABLE_HOW;	/* not set yet */
>  	INIT_WORK(&dreq->work, nfs_direct_write_schedule_work);
>  	spin_lock_init(&dreq->lock);
>  
> @@ -602,7 +690,7 @@ static void nfs_direct_commit_complete(struct nfs_commit_data *data)
>  		dprintk("NFS: %5u commit failed with error %d.\n",
>  			data->task.tk_pid, status);
>  		dreq->flags = NFS_ODIRECT_RESCHED_WRITES;
> -	} else if (memcmp(&dreq->verf, &data->verf, sizeof(data->verf))) {
> +	} else if (nfs_direct_cmp_commit_data_verf(dreq, data)) {
>  		dprintk("NFS: %5u commit verify failed\n", data->task.tk_pid);
>  		dreq->flags = NFS_ODIRECT_RESCHED_WRITES;
>  	}
> @@ -811,13 +899,13 @@ static void nfs_direct_write_completion(struct nfs_pgio_header *hdr)
>  			if (dreq->flags == NFS_ODIRECT_RESCHED_WRITES)
>  				bit = NFS_IOHDR_NEED_RESCHED;
>  			else if (dreq->flags == 0) {
> -				memcpy(&dreq->verf, &hdr->verf,
> -				       sizeof(dreq->verf));
> +				nfs_direct_set_hdr_verf(dreq, hdr);
>  				bit = NFS_IOHDR_NEED_COMMIT;
>  				dreq->flags = NFS_ODIRECT_DO_COMMIT;
>  			} else if (dreq->flags == NFS_ODIRECT_DO_COMMIT) {
> -				if (memcmp(&dreq->verf, &hdr->verf, sizeof(dreq->verf))) {
> -					dreq->flags = NFS_ODIRECT_RESCHED_WRITES;
> +				if (nfs_direct_set_or_cmp_hdr_verf(dreq, hdr)) {
> +					dreq->flags =
> +						NFS_ODIRECT_RESCHED_WRITES;
>  					bit = NFS_IOHDR_NEED_RESCHED;
>  				} else
>  					bit = NFS_IOHDR_NEED_COMMIT;
> diff --git a/fs/nfs/nfs4filelayout.c b/fs/nfs/nfs4filelayout.c
> index 7a665e0..0ebc521 100644
> --- a/fs/nfs/nfs4filelayout.c
> +++ b/fs/nfs/nfs4filelayout.c
> @@ -560,6 +560,7 @@ filelayout_read_pagelist(struct nfs_pgio_data *data)
>  	/* No multipath support. Use first DS */
>  	atomic_inc(&ds->ds_clp->cl_count);
>  	data->ds_clp = ds->ds_clp;
> +	data->ds_idx = idx;
>  	fh = nfs4_fl_select_ds_fh(lseg, j);
>  	if (fh)
>  		data->args.fh = fh;
> @@ -603,6 +604,7 @@ filelayout_write_pagelist(struct nfs_pgio_data *data, int sync)
>  	data->pgio_done_cb = filelayout_write_done_cb;
>  	atomic_inc(&ds->ds_clp->cl_count);
>  	data->ds_clp = ds->ds_clp;
> +	data->ds_idx = idx;
>  	fh = nfs4_fl_select_ds_fh(lseg, j);
>  	if (fh)
>  		data->args.fh = fh;
> @@ -875,6 +877,8 @@ filelayout_alloc_commit_info(struct pnfs_layout_segment *lseg,
>  	for (i = 0; i < size; i++) {
>  		INIT_LIST_HEAD(&buckets[i].written);
>  		INIT_LIST_HEAD(&buckets[i].committing);
> +		/* mark direct verifier as unset */
> +		buckets[i].direct_verf.committed = NFS_INVALID_STABLE_HOW;
>  	}
>  
>  	spin_lock(cinfo->lock);
> @@ -885,6 +889,8 @@ filelayout_alloc_commit_info(struct pnfs_layout_segment *lseg,
>  			    &buckets[i].written);
>  		list_splice(&cinfo->ds->buckets[i].committing,
>  			    &buckets[i].committing);
> +		buckets[i].direct_verf.committed =
> +			cinfo->ds->buckets[i].direct_verf.committed;
>  		buckets[i].wlseg = cinfo->ds->buckets[i].wlseg;
>  		buckets[i].clseg = cinfo->ds->buckets[i].clseg;
>  	}
> diff --git a/include/linux/nfs.h b/include/linux/nfs.h
> index 3e794c1..610af51 100644
> --- a/include/linux/nfs.h
> +++ b/include/linux/nfs.h
> @@ -46,6 +46,9 @@ static inline void nfs_copy_fh(struct nfs_fh *target, const struct nfs_fh *sourc
>  enum nfs3_stable_how {
>  	NFS_UNSTABLE = 0,
>  	NFS_DATA_SYNC = 1,
> -	NFS_FILE_SYNC = 2
> +	NFS_FILE_SYNC = 2,
> +
> +	/* used by direct.c to mark verf as invalid */
> +	NFS_INVALID_STABLE_HOW = -1
>  };
>  #endif /* _LINUX_NFS_H */
> diff --git a/include/linux/nfs_xdr.h b/include/linux/nfs_xdr.h
> index 29828c7..bb9fb88 100644
> --- a/include/linux/nfs_xdr.h
> +++ b/include/linux/nfs_xdr.h
> @@ -1111,6 +1111,7 @@ struct pnfs_commit_bucket {
>  	struct list_head committing;
>  	struct pnfs_layout_segment *wlseg;
>  	struct pnfs_layout_segment *clseg;
> +	struct nfs_writeverf direct_verf;
>  };
>  
>  struct pnfs_ds_commit_info {
> @@ -1294,6 +1295,7 @@ struct nfs_pgio_data {
>  	__u64			mds_offset;	/* Filelayout dense stripe */
>  	struct nfs_page_array	pages;
>  	struct nfs_client	*ds_clp;	/* pNFS data server */
> +	int			ds_idx;		/* ds index if ds_clp is set */
>  };
>  
>  struct nfs_rw_header {