Re: [PATCH v6 01/26] NFSv4.1: use struct nfs_client to qualify deviceid

[Benny Halevy <bhalevy@panasas.com>]

On 2011-05-23 19:34, Benny Halevy wrote:
> deviceids are unique per server, per layout type.
> Therefore, in the global cache in the files layout driver
> deviceids from different servers may clash so we need
> to qualify them with a struct nfs_client that represents
> the nfs server that returned the deviceid.
> 
> Introduced in 2.6.39 commit ea8eecdd
> "NFSv4.1 move deviceid cache to filelayout driver"

Note this is required for stable 2.6.39

Benny
> 
> Signed-off-by: Benny Halevy <bhalevy@panasas.com>
> ---
>  fs/nfs/nfs4filelayout.c    |    2 +-
>  fs/nfs/nfs4filelayout.h    |    3 ++-
>  fs/nfs/nfs4filelayoutdev.c |    9 ++++-----
>  3 files changed, 7 insertions(+), 7 deletions(-)
> 
> diff --git a/fs/nfs/nfs4filelayout.c b/fs/nfs/nfs4filelayout.c
> index be79dc9..ff47fdf 100644
> --- a/fs/nfs/nfs4filelayout.c
> +++ b/fs/nfs/nfs4filelayout.c
> @@ -440,7 +440,7 @@ filelayout_check_layout(struct pnfs_layout_hdr *lo,
>  	}
>  
>  	/* find and reference the deviceid */
> -	dsaddr = nfs4_fl_find_get_deviceid(id);
> +	dsaddr = nfs4_fl_find_get_deviceid(NFS_SERVER(lo->plh_inode)->nfs_client, id);
>  	if (dsaddr == NULL) {
>  		dsaddr = get_device_info(lo->plh_inode, id, gfp_flags);
>  		if (dsaddr == NULL)
> diff --git a/fs/nfs/nfs4filelayout.h b/fs/nfs/nfs4filelayout.h
> index 2b461d7..301b955 100644
> --- a/fs/nfs/nfs4filelayout.h
> +++ b/fs/nfs/nfs4filelayout.h
> @@ -60,6 +60,7 @@ struct nfs4_pnfs_ds {
>  
>  struct nfs4_file_layout_dsaddr {
>  	struct hlist_node		node;
> +	struct nfs_client		*nfs_client;
>  	struct nfs4_deviceid		deviceid;
>  	atomic_t			ref;
>  	unsigned long			flags;
> @@ -101,7 +102,7 @@ u32 nfs4_fl_calc_ds_index(struct pnfs_layout_segment *lseg, u32 j);
>  struct nfs4_pnfs_ds *nfs4_fl_prepare_ds(struct pnfs_layout_segment *lseg,
>  					u32 ds_idx);
>  extern struct nfs4_file_layout_dsaddr *
> -nfs4_fl_find_get_deviceid(struct nfs4_deviceid *dev_id);
> +nfs4_fl_find_get_deviceid(struct nfs_client *, struct nfs4_deviceid *dev_id);
>  extern void nfs4_fl_put_deviceid(struct nfs4_file_layout_dsaddr *dsaddr);
>  struct nfs4_file_layout_dsaddr *
>  get_device_info(struct inode *inode, struct nfs4_deviceid *dev_id, gfp_t gfp_flags);
> diff --git a/fs/nfs/nfs4filelayoutdev.c b/fs/nfs/nfs4filelayoutdev.c
> index db07c7a..42e3266 100644
> --- a/fs/nfs/nfs4filelayoutdev.c
> +++ b/fs/nfs/nfs4filelayoutdev.c
> @@ -431,7 +431,7 @@ decode_device(struct inode *ino, struct pnfs_device *pdev, gfp_t gfp_flags)
>  	dsaddr->stripe_indices = stripe_indices;
>  	stripe_indices = NULL;
>  	dsaddr->ds_num = num;
> -
> +	dsaddr->nfs_client = NFS_SERVER(ino)->nfs_client;
>  	memcpy(&dsaddr->deviceid, &pdev->dev_id, sizeof(pdev->dev_id));
>  
>  	for (i = 0; i < dsaddr->ds_num; i++) {
> @@ -516,7 +516,7 @@ decode_and_add_device(struct inode *inode, struct pnfs_device *dev, gfp_t gfp_fl
>  	}
>  
>  	spin_lock(&filelayout_deviceid_lock);
> -	d = nfs4_fl_find_get_deviceid(&new->deviceid);
> +	d = nfs4_fl_find_get_deviceid(new->nfs_client, &new->deviceid);
>  	if (d) {
>  		spin_unlock(&filelayout_deviceid_lock);
>  		nfs4_fl_free_deviceid(new);
> @@ -610,16 +610,15 @@ nfs4_fl_put_deviceid(struct nfs4_file_layout_dsaddr *dsaddr)
>  }
>  
>  struct nfs4_file_layout_dsaddr *
> -nfs4_fl_find_get_deviceid(struct nfs4_deviceid *id)
> +nfs4_fl_find_get_deviceid(struct nfs_client *clp, struct nfs4_deviceid *id)
>  {
>  	struct nfs4_file_layout_dsaddr *d;
>  	struct hlist_node *n;
>  	long hash = nfs4_fl_deviceid_hash(id);
>  
> -
>  	rcu_read_lock();
>  	hlist_for_each_entry_rcu(d, n, &filelayout_deviceid_cache[hash], node) {
> -		if (!memcmp(&d->deviceid, id, sizeof(*id))) {
> +		if (d->nfs_client == clp && !memcmp(&d->deviceid, id, sizeof(*id))) {
>  			if (!atomic_inc_not_zero(&d->ref))
>  				goto fail;
>  			rcu_read_unlock();