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>

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index d202e04aca942553b3f3b4fa69662c8525c2658f..b4d67feab90b679eb41245a28349f73339dbd2df 100644 (file)
--- 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:
@@ -5060,36 +5076,6 @@ static void nfs4_destroy_slot_tables(struct nfs4_session *session)
        return;
 }
 
-/*
- * 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
  */
@@ -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;
 }