NFS: change access cache to use 'struct cred'.

Rather than keying the access cache with 'struct rpc_cred',
use 'struct cred'.  Then use cred_fscmp() to compare
credentials rather than comparing the raw pointer.

A benefit of this approach is that in the common case we avoid the
rpc_lookup_cred_nonblock() call which can be slow when the cred cache is large.
This also keeps many fewer items pinned in the rpc cred cache, so the
cred cache is less likely to get large.

Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

1 files changed, 12 insertions, 4 deletions

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index cafa155a053e..bf97331c02d3 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -1772,7 +1772,7 @@ static struct nfs4_state *nfs4_try_open_cached(struct nfs4_opendata *opendata)
 		rcu_read_unlock();
 		nfs_release_seqid(opendata->o_arg.seqid);
 		if (!opendata->is_recover) {
-			ret = nfs_may_open(state->inode, state->owner->so_cred, open_mode);
+			ret = nfs_may_open(state->inode, state->owner->so_cred->cr_cred, open_mode);
 			if (ret != 0)
 				goto out;
 		}
@@ -2511,7 +2511,7 @@ static int nfs4_opendata_access(struct rpc_cred *cred,
 	} else if ((fmode & FMODE_READ) && !opendata->file_created)
 		mask = NFS4_ACCESS_READ;
 
-	cache.cred = cred;
+	cache.cred = cred->cr_cred;
 	nfs_access_set_mask(&cache, opendata->o_res.access_result);
 	nfs_access_add_cache(state->inode, &cache);
 
@@ -4188,18 +4188,25 @@ static int _nfs4_proc_access(struct inode *inode, struct nfs_access_entry *entry
 	struct nfs4_accessres res = {
 		.server = server,
 	};
+	struct auth_cred acred = {
+		.cred = entry->cred,
+	};
 	struct rpc_message msg = {
 		.rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_ACCESS],
 		.rpc_argp = &args,
 		.rpc_resp = &res,
-		.rpc_cred = entry->cred,
+		.rpc_cred = rpc_lookup_generic_cred(&acred, 0, GFP_NOFS),
 	};
 	int status = 0;
 
+	if (!msg.rpc_cred)
+		return -ENOMEM;
 	if (!nfs4_have_delegation(inode, FMODE_READ)) {
 		res.fattr = nfs_alloc_fattr();
-		if (res.fattr == NULL)
+		if (res.fattr == NULL) {
+			put_rpccred(msg.rpc_cred);
 			return -ENOMEM;
+		}
 		args.bitmask = server->cache_consistency_bitmask;
 	}
 
@@ -4210,6 +4217,7 @@ static int _nfs4_proc_access(struct inode *inode, struct nfs_access_entry *entry
 			nfs_refresh_inode(inode, res.fattr);
 	}
 	nfs_free_fattr(res.fattr);
+	put_rpccred(msg.rpc_cred);
 	return status;
 }