nfs: have ff_layout_get_ds_cred take a reference to the cred

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@primarydata.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

diff --git a/fs/nfs/flexfilelayout/flexfilelayout.c b/fs/nfs/flexfilelayout/flexfilelayout.c
index 3b398f7b4637bce97e2cf1ecba96b9359c5b5cab..1f46043c181e4c7836bb4990c9af5874de6cd08f 100644 (file)
--- a/fs/nfs/flexfilelayout/flexfilelayout.c
+++ b/fs/nfs/flexfilelayout/flexfilelayout.c
@@ -1712,7 +1712,7 @@ ff_layout_read_pagelist(struct nfs_pgio_header *hdr)
                goto out_failed;
 
        ds_cred = ff_layout_get_ds_cred(lseg, idx, hdr->cred);
-       if (IS_ERR(ds_cred))
+       if (!ds_cred)
                goto out_failed;
 
        vers = nfs4_ff_layout_ds_version(lseg, idx);
@@ -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:
@@ -1769,7 +1769,7 @@ ff_layout_write_pagelist(struct nfs_pgio_header *hdr, int sync)
                return PNFS_NOT_ATTEMPTED;
 
        ds_cred = ff_layout_get_ds_cred(lseg, idx, hdr->cred);
-       if (IS_ERR(ds_cred))
+       if (!ds_cred)
                return PNFS_NOT_ATTEMPTED;
 
        vers = nfs4_ff_layout_ds_version(lseg, idx);
@@ -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);
@@ -1838,7 +1839,7 @@ static int ff_layout_initiate_commit(struct nfs_commit_data *data, int how)
                goto out_err;
 
        ds_cred = ff_layout_get_ds_cred(lseg, idx, data->cred);
-       if (IS_ERR(ds_cred))
+       if (!ds_cred)
                goto out_err;
 
        vers = nfs4_ff_layout_ds_version(lseg, idx);
@@ -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 a0dbf94d15ae61739e4cde6b66c7df776218cc12..baee22929174b8bd90c4d371528ba07705345c5f 100644 (file)
--- 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;
 }