NFSv4.x: Allow multiple callbacks in flight
Hook the callback channel into the same session management machinery
as we use for the forward channel.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
diff --git a/fs/nfs/callback.h b/fs/nfs/callback.h
index ff8195b..5fe1cec 100644
--- a/fs/nfs/callback.h
+++ b/fs/nfs/callback.h
@@ -37,10 +37,11 @@
OP_CB_ILLEGAL = 10044,
};
+struct nfs4_slot;
struct cb_process_state {
__be32 drc_status;
struct nfs_client *clp;
- u32 slotid;
+ struct nfs4_slot *slot;
u32 minorversion;
struct net *net;
};
diff --git a/fs/nfs/callback_proc.c b/fs/nfs/callback_proc.c
index 79c93b3..efd079d 100644
--- a/fs/nfs/callback_proc.c
+++ b/fs/nfs/callback_proc.c
@@ -367,7 +367,7 @@
if (args->csa_sequenceid == slot->seq_nr) {
dprintk("%s seqid %u is a replay\n",
__func__, args->csa_sequenceid);
- if (tbl->highest_used_slotid != NFS4_NO_SLOT)
+ if (nfs4_test_locked_slot(tbl, slot->slot_nr))
return htonl(NFS4ERR_DELAY);
/* Signal process_op to set this error on next op */
if (args->csa_cachethis == 0)
@@ -476,12 +476,18 @@
goto out_unlock;
}
+ status = htonl(NFS4ERR_BADSLOT);
+ slot = nfs4_lookup_slot(tbl, args->csa_slotid);
+ if (IS_ERR(slot))
+ goto out_unlock;
status = validate_seqid(tbl, slot, args);
if (status)
goto out_unlock;
-
- cps->slotid = args->csa_slotid;
- tbl->highest_used_slotid = args->csa_slotid;
+ if (!nfs4_try_to_lock_slot(tbl, slot)) {
+ status = htonl(NFS4ERR_DELAY);
+ goto out_unlock;
+ }
+ cps->slot = slot;
memcpy(&res->csr_sessionid, &args->csa_sessionid,
sizeof(res->csr_sessionid));
diff --git a/fs/nfs/callback_xdr.c b/fs/nfs/callback_xdr.c
index 646cdac..976c906 100644
--- a/fs/nfs/callback_xdr.c
+++ b/fs/nfs/callback_xdr.c
@@ -752,7 +752,8 @@
return htonl(NFS_OK);
}
-static void nfs4_callback_free_slot(struct nfs4_session *session)
+static void nfs4_callback_free_slot(struct nfs4_session *session,
+ struct nfs4_slot *slot)
{
struct nfs4_slot_table *tbl = &session->bc_slot_table;
@@ -761,15 +762,17 @@
* Let the state manager know callback processing done.
* A single slot, so highest used slotid is either 0 or -1
*/
- tbl->highest_used_slotid = NFS4_NO_SLOT;
+ nfs4_free_slot(tbl, slot);
nfs4_slot_tbl_drain_complete(tbl);
spin_unlock(&tbl->slot_tbl_lock);
}
static void nfs4_cb_free_slot(struct cb_process_state *cps)
{
- if (cps->slotid != NFS4_NO_SLOT)
- nfs4_callback_free_slot(cps->clp->cl_session);
+ if (cps->slot) {
+ nfs4_callback_free_slot(cps->clp->cl_session, cps->slot);
+ cps->slot = NULL;
+ }
}
#else /* CONFIG_NFS_V4_1 */
@@ -893,7 +896,6 @@
struct cb_process_state cps = {
.drc_status = 0,
.clp = NULL,
- .slotid = NFS4_NO_SLOT,
.net = SVC_NET(rqstp),
};
unsigned int nops = 0;
diff --git a/fs/nfs/nfs4session.c b/fs/nfs/nfs4session.c
index e23366e..332d06e 100644
--- a/fs/nfs/nfs4session.c
+++ b/fs/nfs/nfs4session.c
@@ -135,6 +135,43 @@
return ERR_PTR(-ENOMEM);
}
+static void nfs4_lock_slot(struct nfs4_slot_table *tbl,
+ struct nfs4_slot *slot)
+{
+ u32 slotid = slot->slot_nr;
+
+ __set_bit(slotid, tbl->used_slots);
+ if (slotid > tbl->highest_used_slotid ||
+ tbl->highest_used_slotid == NFS4_NO_SLOT)
+ tbl->highest_used_slotid = slotid;
+ slot->generation = tbl->generation;
+}
+
+/*
+ * nfs4_try_to_lock_slot - Given a slot try to allocate it
+ *
+ * Note: must be called with the slot_tbl_lock held.
+ */
+bool nfs4_try_to_lock_slot(struct nfs4_slot_table *tbl, struct nfs4_slot *slot)
+{
+ if (nfs4_test_locked_slot(tbl, slot->slot_nr))
+ return false;
+ nfs4_lock_slot(tbl, slot);
+ return true;
+}
+
+/*
+ * nfs4_lookup_slot - Find a slot but don't allocate it
+ *
+ * Note: must be called with the slot_tbl_lock held.
+ */
+struct nfs4_slot *nfs4_lookup_slot(struct nfs4_slot_table *tbl, u32 slotid)
+{
+ if (slotid <= tbl->max_slotid)
+ return nfs4_find_or_create_slot(tbl, slotid, 1, GFP_NOWAIT);
+ return ERR_PTR(-E2BIG);
+}
+
/*
* nfs4_alloc_slot - efficiently look for a free slot
*
@@ -153,18 +190,11 @@
__func__, tbl->used_slots[0], tbl->highest_used_slotid,
tbl->max_slotid + 1);
slotid = find_first_zero_bit(tbl->used_slots, tbl->max_slotid + 1);
- if (slotid > tbl->max_slotid)
- goto out;
- ret = nfs4_find_or_create_slot(tbl, slotid, 1, GFP_NOWAIT);
- if (IS_ERR(ret))
- goto out;
- __set_bit(slotid, tbl->used_slots);
- if (slotid > tbl->highest_used_slotid ||
- tbl->highest_used_slotid == NFS4_NO_SLOT)
- tbl->highest_used_slotid = slotid;
- ret->generation = tbl->generation;
-
-out:
+ if (slotid <= tbl->max_slotid) {
+ ret = nfs4_find_or_create_slot(tbl, slotid, 1, GFP_NOWAIT);
+ if (!IS_ERR(ret))
+ nfs4_lock_slot(tbl, ret);
+ }
dprintk("<-- %s used_slots=%04lx highest_used=%u slotid=%u\n",
__func__, tbl->used_slots[0], tbl->highest_used_slotid,
!IS_ERR(ret) ? ret->slot_nr : NFS4_NO_SLOT);
diff --git a/fs/nfs/nfs4session.h b/fs/nfs/nfs4session.h
index e3ea2c5..5b51298d 100644
--- a/fs/nfs/nfs4session.h
+++ b/fs/nfs/nfs4session.h
@@ -77,6 +77,8 @@
unsigned int max_reqs, const char *queue);
extern void nfs4_shutdown_slot_table(struct nfs4_slot_table *tbl);
extern struct nfs4_slot *nfs4_alloc_slot(struct nfs4_slot_table *tbl);
+extern struct nfs4_slot *nfs4_lookup_slot(struct nfs4_slot_table *tbl, u32 slotid);
+extern bool nfs4_try_to_lock_slot(struct nfs4_slot_table *tbl, struct nfs4_slot *slot);
extern void nfs4_free_slot(struct nfs4_slot_table *tbl, struct nfs4_slot *slot);
extern void nfs4_slot_tbl_drain_complete(struct nfs4_slot_table *tbl);
bool nfs41_wake_and_assign_slot(struct nfs4_slot_table *tbl,
@@ -88,6 +90,12 @@
return !!test_bit(NFS4_SLOT_TBL_DRAINING, &tbl->slot_tbl_state);
}
+static inline bool nfs4_test_locked_slot(const struct nfs4_slot_table *tbl,
+ u32 slotid)
+{
+ return !!test_bit(slotid, tbl->used_slots);
+}
+
#if defined(CONFIG_NFS_V4_1)
extern void nfs41_set_target_slotid(struct nfs4_slot_table *tbl,
u32 target_highest_slotid);
