nfsd: turn on reply cache for NFSv4

It's sort of ridiculous that we've never had a working reply cache for
NFSv4.

On the other hand, we may still not: our current reply cache is likely
not very good, especially in the TCP case (which is the only case that
matters for v4).  What we really need here is some serious testing.

Anyway, here's a start.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>

1 files changed, 22 insertions, 10 deletions

diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index 7ef1b27f1125..e80777666618 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -1007,6 +1007,15 @@ struct nfsd4_operation {
 	nfsd4op_func op_func;
 	u32 op_flags;
 	char *op_name;
+	/*
+	 * We use the DRC for compounds containing non-idempotent
+	 * operations, *except* those that are 4.1-specific (since
+	 * sessions provide their own EOS), and except for stateful
+	 * operations other than setclientid and setclientid_confirm
+	 * (since sequence numbers provide EOS for open, lock, etc in
+	 * the v4.0 case).
+	 */
+	bool op_cacheresult;
 };
 
 static struct nfsd4_operation nfsd4_ops[];
@@ -1051,6 +1060,11 @@ static inline struct nfsd4_operation *OPDESC(struct nfsd4_op *op)
 	return &nfsd4_ops[op->opnum];
 }
 
+bool nfsd4_cache_this_op(struct nfsd4_op *op)
+{
+	return OPDESC(op)->op_cacheresult;
+}
+
 static bool need_wrongsec_check(struct svc_rqst *rqstp)
 {
 	struct nfsd4_compoundres *resp = rqstp->rq_resp;
@@ -1240,6 +1254,7 @@ static struct nfsd4_operation nfsd4_ops[] = {
 	[OP_CREATE] = {
 		.op_func = (nfsd4op_func)nfsd4_create,
 		.op_name = "OP_CREATE",
+		.op_cacheresult = true,
 	},
 	[OP_DELEGRETURN] = {
 		.op_func = (nfsd4op_func)nfsd4_delegreturn,
@@ -1257,6 +1272,7 @@ static struct nfsd4_operation nfsd4_ops[] = {
 	[OP_LINK] = {
 		.op_func = (nfsd4op_func)nfsd4_link,
 		.op_name = "OP_LINK",
+		.op_cacheresult = true,
 	},
 	[OP_LOCK] = {
 		.op_func = (nfsd4op_func)nfsd4_lock,
@@ -1330,10 +1346,12 @@ static struct nfsd4_operation nfsd4_ops[] = {
 	[OP_REMOVE] = {
 		.op_func = (nfsd4op_func)nfsd4_remove,
 		.op_name = "OP_REMOVE",
+		.op_cacheresult = true,
 	},
 	[OP_RENAME] = {
 		.op_name = "OP_RENAME",
 		.op_func = (nfsd4op_func)nfsd4_rename,
+		.op_cacheresult = true,
 	},
 	[OP_RENEW] = {
 		.op_func = (nfsd4op_func)nfsd4_renew,
@@ -1359,16 +1377,19 @@ static struct nfsd4_operation nfsd4_ops[] = {
 	[OP_SETATTR] = {
 		.op_func = (nfsd4op_func)nfsd4_setattr,
 		.op_name = "OP_SETATTR",
+		.op_cacheresult = true,
 	},
 	[OP_SETCLIENTID] = {
 		.op_func = (nfsd4op_func)nfsd4_setclientid,
 		.op_flags = ALLOWED_WITHOUT_FH | ALLOWED_ON_ABSENT_FS,
 		.op_name = "OP_SETCLIENTID",
+		.op_cacheresult = true,
 	},
 	[OP_SETCLIENTID_CONFIRM] = {
 		.op_func = (nfsd4op_func)nfsd4_setclientid_confirm,
 		.op_flags = ALLOWED_WITHOUT_FH | ALLOWED_ON_ABSENT_FS,
 		.op_name = "OP_SETCLIENTID_CONFIRM",
+		.op_cacheresult = true,
 	},
 	[OP_VERIFY] = {
 		.op_func = (nfsd4op_func)nfsd4_verify,
@@ -1377,6 +1398,7 @@ static struct nfsd4_operation nfsd4_ops[] = {
 	[OP_WRITE] = {
 		.op_func = (nfsd4op_func)nfsd4_write,
 		.op_name = "OP_WRITE",
+		.op_cacheresult = true,
 	},
 	[OP_RELEASE_LOCKOWNER] = {
 		.op_func = (nfsd4op_func)nfsd4_release_lockowner,
@@ -1447,16 +1469,6 @@ static const char *nfsd4_op_name(unsigned opnum)
 #define nfsd4_voidres			nfsd4_voidargs
 struct nfsd4_voidargs { int dummy; };
 
-/*
- * TODO: At the present time, the NFSv4 server does not do XID caching
- * of requests.  Implementing XID caching would not be a serious problem,
- * although it would require a mild change in interfaces since one
- * doesn't know whether an NFSv4 request is idempotent until after the
- * XDR decode.  However, XID caching totally confuses pynfs (Peter
- * Astrand's regression testsuite for NFSv4 servers), which reuses
- * XID's liberally, so I've left it unimplemented until pynfs generates
- * better XID's.
- */
 static struct svc_procedure		nfsd_procedures4[2] = {
 	[NFSPROC4_NULL] = {
 		.pc_func = (svc_procfunc) nfsd4_proc_null,