On Thu, 2016-04-14 at 08:37 -0400, Jeff Layton wrote:
> In later patches, we're going to want to allow the creds to be updated
> when we get a new layout with updated creds. Have this function take
> a reference to the cred that is later put once the call has been
> dispatched.
>
> Also, prepare for this change by ensuring we follow RCU rules when
> getting a reference to the cred as well.
>
> Signed-off-by: Jeff Layton <jeff.layton@xxxxxxxxxxxxxxx>
> ---
> fs/nfs/flexfilelayout/flexfilelayout.c | 9 ++++++---
> fs/nfs/flexfilelayout/flexfilelayoutdev.c | 30 ++++++++++++++++++++++++++----
> 2 files changed, 32 insertions(+), 7 deletions(-)
>
> diff --git a/fs/nfs/flexfilelayout/flexfilelayout.c b/fs/nfs/flexfilelayout/flexfilelayout.c
> index 0cb1abd535e3..ba48fdf960e0 100644
> --- a/fs/nfs/flexfilelayout/flexfilelayout.c
> +++ b/fs/nfs/flexfilelayout/flexfilelayout.c
> @@ -1737,7 +1737,7 @@ ff_layout_read_pagelist(struct nfs_pgio_header *hdr)
> vers == 3 ? &ff_layout_read_call_ops_v3 :
> &ff_layout_read_call_ops_v4,
> 0, RPC_TASK_SOFTCONN);
> -
> + put_rpccred(ds_cred);
> return PNFS_ATTEMPTED;
>
> out_failed:
> @@ -1798,6 +1798,7 @@ ff_layout_write_pagelist(struct nfs_pgio_header *hdr, int sync)
> vers == 3 ? &ff_layout_write_call_ops_v3 :
> &ff_layout_write_call_ops_v4,
> sync, RPC_TASK_SOFTCONN);
> + put_rpccred(ds_cred);
> return PNFS_ATTEMPTED;
> }
>
> @@ -1824,7 +1825,7 @@ static int ff_layout_initiate_commit(struct nfs_commit_data *data, int how)
> struct rpc_clnt *ds_clnt;
> struct rpc_cred *ds_cred;
> u32 idx;
> - int vers;
> + int vers, ret;
> struct nfs_fh *fh;
>
> idx = calc_ds_index_from_commit(lseg, data->ds_commit_index);
> @@ -1854,10 +1855,12 @@ static int ff_layout_initiate_commit(struct nfs_commit_data *data, int how)
> if (fh)
> data->args.fh = fh;
>
> - return nfs_initiate_commit(ds_clnt, data, ds->ds_clp->rpc_ops,
> + ret = nfs_initiate_commit(ds_clnt, data, ds->ds_clp->rpc_ops,
> vers == 3 ? &ff_layout_commit_call_ops_v3 :
> &ff_layout_commit_call_ops_v4,
> how, RPC_TASK_SOFTCONN);
> + put_rpccred(ds_cred);
> + return ret;
> out_err:
> pnfs_generic_prepare_to_resend_writes(data);
> pnfs_generic_commit_release(data);
> diff --git a/fs/nfs/flexfilelayout/flexfilelayoutdev.c b/fs/nfs/flexfilelayout/flexfilelayoutdev.c
> index a0dbf94d15ae..baee22929174 100644
> --- a/fs/nfs/flexfilelayout/flexfilelayoutdev.c
> +++ b/fs/nfs/flexfilelayout/flexfilelayoutdev.c
> @@ -338,6 +338,25 @@ static int ff_layout_update_mirror_cred(struct nfs4_ff_layout_mirror *mirror,
> return 0;
> }
>
> +static struct rpc_cred *
> +ff_layout_get_mirror_cred(struct nfs4_ff_layout_mirror *mirror, u32 iomode)
> +{
> + struct rpc_cred *cred, **pcred;
> +
> + pcred = &mirror->cred;
> +
> + rcu_read_lock();
> + do {
> + cred = rcu_dereference(*pcred);
> + if (!cred)
> + break;
> +
> + cred = get_rpccred_rcu(cred);
> + } while(!cred);
> + rcu_read_unlock();
> + return cred;
> +}
> +
> struct nfs_fh *
> nfs4_ff_layout_select_ds_fh(struct pnfs_layout_segment *lseg, u32 mirror_idx)
> {
> @@ -435,10 +454,13 @@ ff_layout_get_ds_cred(struct pnfs_layout_segment *lseg, u32 ds_idx,
> struct nfs4_ff_layout_mirror *mirror = FF_LAYOUT_COMP(lseg, ds_idx);
> struct rpc_cred *cred;
>
> - if (mirror && mirror->cred)
> - cred = mirror->cred;
> - else
> - cred = mdscred;
> + if (mirror) {
> + cred = ff_layout_get_mirror_cred(mirror, lseg->pls_range.iomode);
> + if (!cred)
> + cred = get_rpccred(mdscred);
> + } else {
> + cred = get_rpccred(mdscred);
> + }
> return cred;
> }
>
Oops, there's something missing in this patch. We need to fix the
callers of ff_layout_get_ds_cred to check to see if they get a NULL
pointer back. I'll fix that in the next version of the set.
--
Jeff Layton <jlayton@xxxxxxxxxxxxxxx>
--
To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
