NFSv4.1: Fix a NFSv4.1 session initialisation regression

Commit aacd553 (NFSv4.1: cleanup init and reset of session slot tables)
introduces a regression in the session initialisation code. New tables
now find their sequence ids initialised to 0, rather than the mandated
value of 1 (see RFC5661).

Fix the problem by merging nfs4_reset_slot_table() and nfs4_init_slot_table().
Since the tbl->max_slots is initialised to 0, the test in
nfs4_reset_slot_table for max_reqs != tbl->max_slots will automatically
pass for an empty table.

Reported-by: Vitaliy Gusev <gusev.vitaliy@nexenta.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 42 insertions, 65 deletions

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index d202e04aca94..b4d67feab90b 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -5008,37 +5008,53 @@ int nfs4_proc_get_lease_time(struct nfs_client *clp, struct nfs_fsinfo *fsinfo)
         return status;
 }
 
+static struct nfs4_slot *nfs4_alloc_slots(u32 max_slots, gfp_t gfp_flags)
+{
+        return kcalloc(max_slots, sizeof(struct nfs4_slot), gfp_flags);
+}
+
+static void nfs4_add_and_init_slots(struct nfs4_slot_table *tbl,
+                struct nfs4_slot *new,
+                u32 max_slots,
+                u32 ivalue)
+{
+        struct nfs4_slot *old = NULL;
+        u32 i;
+
+        spin_lock(&tbl->slot_tbl_lock);
+        if (new) {
+                old = tbl->slots;
+                tbl->slots = new;
+                tbl->max_slots = max_slots;
+        }
+        tbl->highest_used_slotid = -1;  /* no slot is currently used */
+        for (i = 0; i < tbl->max_slots; i++)
+                tbl->slots[i].seq_nr = ivalue;
+        spin_unlock(&tbl->slot_tbl_lock);
+        kfree(old);
+}
+
 /*
- * Reset a slot table
+ * (re)Initialise a slot table
  */
-static int nfs4_reset_slot_table(struct nfs4_slot_table *tbl, u32 max_reqs,
-                                 int ivalue)
+static int nfs4_realloc_slot_table(struct nfs4_slot_table *tbl, u32 max_reqs,
+                                 u32 ivalue)
 {
         struct nfs4_slot *new = NULL;
-        int i;
-        int ret = 0;
+        int ret = -ENOMEM;
 
         dprintk("--> %s: max_reqs=%u, tbl->max_slots %d\n", __func__,
                 max_reqs, tbl->max_slots);
 
         /* Does the newly negotiated max_reqs match the existing slot table? */
         if (max_reqs != tbl->max_slots) {
-                ret = -ENOMEM;
-                new = kmalloc(max_reqs * sizeof(struct nfs4_slot),
-                              GFP_NOFS);
+                new = nfs4_alloc_slots(max_reqs, GFP_NOFS);
                 if (!new)
                         goto out;
-                ret = 0;
-                kfree(tbl->slots);
-        }
-        spin_lock(&tbl->slot_tbl_lock);
-        if (new) {
-                tbl->slots = new;
-                tbl->max_slots = max_reqs;
         }
-        for (i = 0; i < tbl->max_slots; ++i)
-                tbl->slots[i].seq_nr = ivalue;
-        spin_unlock(&tbl->slot_tbl_lock);
+        ret = 0;
+
+        nfs4_add_and_init_slots(tbl, new, max_reqs, ivalue);
         dprintk("%s: tbl=%p slots=%p max_slots=%d\n", __func__,
                 tbl, tbl->slots, tbl->max_slots);
 out:
@@ -5061,36 +5077,6 @@ static void nfs4_destroy_slot_tables(struct nfs4_session *session)
 }
 
 /*
- * Initialize slot table
- */
-static int nfs4_init_slot_table(struct nfs4_slot_table *tbl,
-                int max_slots, int ivalue)
-{
-        struct nfs4_slot *slot;
-        int ret = -ENOMEM;
-
-        BUG_ON(max_slots > NFS4_MAX_SLOT_TABLE);
-
-        dprintk("--> %s: max_reqs=%u\n", __func__, max_slots);
-
-        slot = kcalloc(max_slots, sizeof(struct nfs4_slot), GFP_NOFS);
-        if (!slot)
-                goto out;
-        ret = 0;
-
-        spin_lock(&tbl->slot_tbl_lock);
-        tbl->max_slots = max_slots;
-        tbl->slots = slot;
-        tbl->highest_used_slotid = -1;  /* no slot is currently used */
-        spin_unlock(&tbl->slot_tbl_lock);
-        dprintk("%s: tbl=%p slots=%p max_slots=%d\n", __func__,
-                tbl, tbl->slots, tbl->max_slots);
-out:
-        dprintk("<-- %s: return %d\n", __func__, ret);
-        return ret;
-}
-
-/*
  * Initialize or reset the forechannel and backchannel tables
  */
 static int nfs4_setup_session_slot_tables(struct nfs4_session *ses)
@@ -5101,25 +5087,16 @@ static int nfs4_setup_session_slot_tables(struct nfs4_session *ses)
         dprintk("--> %s\n", __func__);
         /* Fore channel */
         tbl = &ses->fc_slot_table;
-        if (tbl->slots == NULL) {
-                status = nfs4_init_slot_table(tbl, ses->fc_attrs.max_reqs, 1);
-                if (status) /* -ENOMEM */
-                        return status;
-        } else {
-                status = nfs4_reset_slot_table(tbl, ses->fc_attrs.max_reqs, 1);
-                if (status)
-                        return status;
-        }
+        status = nfs4_realloc_slot_table(tbl, ses->fc_attrs.max_reqs, 1);
+        if (status) /* -ENOMEM */
+                return status;
         /* Back channel */
         tbl = &ses->bc_slot_table;
-        if (tbl->slots == NULL) {
-                status = nfs4_init_slot_table(tbl, ses->bc_attrs.max_reqs, 0);
-                if (status)
-                        /* Fore and back channel share a connection so get
-                         * both slot tables or neither */
-                        nfs4_destroy_slot_tables(ses);
-        } else
-                status = nfs4_reset_slot_table(tbl, ses->bc_attrs.max_reqs, 0);
+        status = nfs4_realloc_slot_table(tbl, ses->bc_attrs.max_reqs, 0);
+        if (status && tbl->slots == NULL)
+                /* Fore and back channel share a connection so get
+                 * both slot tables or neither */
+                nfs4_destroy_slot_tables(ses);
         return status;
 }