NFSv4.1: keep seq_res.sr_slot as pointer rather than an index

Having to explicitly initialize sr_slotid to NFS4_MAX_SLOT_TABLE
resulted in numerous bugs.  Keeping the current slot as a pointer
to the slot table is more straight forward and robust as it's
implicitly set up to NULL wherever the seq_res member is initialized
to zeroes.

Signed-off-by: Benny Halevy <bhalevy@panasas.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 72aa706..aee1bcc 100644 (file)
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -334,10 +334,12 @@ static void renew_lease(const struct nfs_server *server, unsigned long timestamp
  * Must be called while holding tbl->slot_tbl_lock
  */
 static void
-nfs4_free_slot(struct nfs4_slot_table *tbl, u8 free_slotid)
+nfs4_free_slot(struct nfs4_slot_table *tbl, struct nfs4_slot *free_slot)
 {
+       int free_slotid = free_slot - tbl->slots;
        int slotid = free_slotid;
 
+       BUG_ON(slotid < 0 || slotid >= NFS4_MAX_SLOT_TABLE);
        /* clear used bit in bitmap */
        __clear_bit(slotid, tbl->used_slots);
 
@@ -379,7 +381,7 @@ static void nfs41_sequence_free_slot(struct nfs4_sequence_res *res)
        struct nfs4_slot_table *tbl;
 
        tbl = &res->sr_session->fc_slot_table;
-       if (res->sr_slotid == NFS4_MAX_SLOT_TABLE) {
+       if (!res->sr_slot) {
                /* just wake up the next guy waiting since
                 * we may have not consumed a slot after all */
                dprintk("%s: No slot\n", __func__);
@@ -387,17 +389,15 @@ static void nfs41_sequence_free_slot(struct nfs4_sequence_res *res)
        }
 
        spin_lock(&tbl->slot_tbl_lock);
-       nfs4_free_slot(tbl, res->sr_slotid);
+       nfs4_free_slot(tbl, res->sr_slot);
        nfs41_check_drain_session_complete(res->sr_session);
        spin_unlock(&tbl->slot_tbl_lock);
-       res->sr_slotid = NFS4_MAX_SLOT_TABLE;
+       res->sr_slot = NULL;
 }
 
 static int nfs41_sequence_done(struct rpc_task *task, struct nfs4_sequence_res *res)
 {
        unsigned long timestamp;
-       struct nfs4_slot_table *tbl;
-       struct nfs4_slot *slot;
        struct nfs_client *clp;
 
        /*
@@ -410,17 +410,14 @@ static int nfs41_sequence_done(struct rpc_task *task, struct nfs4_sequence_res *
                res->sr_status = NFS_OK;
 
        /* -ERESTARTSYS can result in skipping nfs41_sequence_setup */
-       if (res->sr_slotid == NFS4_MAX_SLOT_TABLE)
+       if (!res->sr_slot)
                goto out;
 
-       tbl = &res->sr_session->fc_slot_table;
-       slot = tbl->slots + res->sr_slotid;
-
        /* Check the SEQUENCE operation status */
        switch (res->sr_status) {
        case 0:
                /* Update the slot's sequence and clientid lease timer */
-               ++slot->seq_nr;
+               ++res->sr_slot->seq_nr;
                timestamp = res->sr_renewal_time;
                clp = res->sr_session->clp;
                do_renew_lease(clp, timestamp);
@@ -433,12 +430,14 @@ static int nfs41_sequence_done(struct rpc_task *task, struct nfs4_sequence_res *
                 * returned NFS4ERR_DELAY as per Section 2.10.6.2
                 * of RFC5661.
                 */
-               dprintk("%s: slot=%d seq=%d: Operation in progress\n",
-                               __func__, res->sr_slotid, slot->seq_nr);
+               dprintk("%s: slot=%ld seq=%d: Operation in progress\n",
+                       __func__,
+                       res->sr_slot - res->sr_session->fc_slot_table.slots,
+                       res->sr_slot->seq_nr);
                goto out_retry;
        default:
                /* Just update the slot sequence no. */
-               ++slot->seq_nr;
+               ++res->sr_slot->seq_nr;
        }
 out:
        /* The session may be reset by one of the error handlers. */
@@ -505,10 +504,9 @@ static int nfs41_setup_sequence(struct nfs4_session *session,
 
        dprintk("--> %s\n", __func__);
        /* slot already allocated? */
-       if (res->sr_slotid != NFS4_MAX_SLOT_TABLE)
+       if (res->sr_slot != NULL)
                return 0;
 
-       res->sr_slotid = NFS4_MAX_SLOT_TABLE;
        tbl = &session->fc_slot_table;
 
        spin_lock(&tbl->slot_tbl_lock);
@@ -550,7 +548,7 @@ static int nfs41_setup_sequence(struct nfs4_session *session,
        dprintk("<-- %s slotid=%d seqid=%d\n", __func__, slotid, slot->seq_nr);
 
        res->sr_session = session;
-       res->sr_slotid = slotid;
+       res->sr_slot = slot;
        res->sr_renewal_time = jiffies;
        res->sr_status_flags = 0;
        /*
@@ -576,8 +574,9 @@ int nfs4_setup_sequence(const struct nfs_server *server,
                goto out;
        }
 
-       dprintk("--> %s clp %p session %p sr_slotid %d\n",
-               __func__, session->clp, session, res->sr_slotid);
+       dprintk("--> %s clp %p session %p sr_slot %ld\n",
+               __func__, session->clp, session, res->sr_slot ?
+                       res->sr_slot - session->fc_slot_table.slots : -1);
 
        ret = nfs41_setup_sequence(session, args, res, cache_reply,
                                   task);
@@ -650,7 +649,7 @@ static int nfs4_call_sync_sequence(struct nfs_server *server,
                .callback_data = &data
        };
 
-       res->sr_slotid = NFS4_MAX_SLOT_TABLE;
+       res->sr_slot = NULL;
        if (privileged)
                task_setup.callback_ops = &nfs41_call_priv_sync_ops;
        task = rpc_run_task(&task_setup);
@@ -735,7 +734,6 @@ static void nfs4_init_opendata_res(struct nfs4_opendata *p)
        p->o_res.server = p->o_arg.server;
        nfs_fattr_init(&p->f_attr);
        nfs_fattr_init(&p->dir_attr);
-       p->o_res.seq_res.sr_slotid = NFS4_MAX_SLOT_TABLE;
 }
 
 static struct nfs4_opendata *nfs4_opendata_alloc(struct path *path,
@@ -1975,7 +1973,6 @@ int nfs4_do_close(struct path *path, struct nfs4_state *state, gfp_t gfp_mask, i
        calldata->res.fattr = &calldata->fattr;
        calldata->res.seqid = calldata->arg.seqid;
        calldata->res.server = server;
-       calldata->res.seq_res.sr_slotid = NFS4_MAX_SLOT_TABLE;
        path_get(path);
        calldata->path = *path;
 
@@ -2550,7 +2547,7 @@ static void nfs4_proc_unlink_setup(struct rpc_message *msg, struct inode *dir)
 
        args->bitmask = server->cache_consistency_bitmask;
        res->server = server;
-       res->seq_res.sr_slotid = NFS4_MAX_SLOT_TABLE;
+       res->seq_res.sr_slot = NULL;
        msg->rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_REMOVE];
 }
 
@@ -2576,7 +2573,6 @@ static void nfs4_proc_rename_setup(struct rpc_message *msg, struct inode *dir)
        msg->rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_RENAME];
        arg->bitmask = server->attr_bitmask;
        res->server = server;
-       res->seq_res.sr_slotid = NFS4_MAX_SLOT_TABLE;
 }
 
 static int nfs4_proc_rename_done(struct rpc_task *task, struct inode *old_dir,
@@ -3646,7 +3642,6 @@ static int _nfs4_proc_delegreturn(struct inode *inode, struct rpc_cred *cred, co
        memcpy(&data->stateid, stateid, sizeof(data->stateid));
        data->res.fattr = &data->fattr;
        data->res.server = server;
-       data->res.seq_res.sr_slotid = NFS4_MAX_SLOT_TABLE;
        nfs_fattr_init(data->res.fattr);
        data->timestamp = jiffies;
        data->rpc_status = 0;
@@ -3799,7 +3794,6 @@ static struct nfs4_unlockdata *nfs4_alloc_unlockdata(struct file_lock *fl,
        p->arg.fl = &p->fl;
        p->arg.seqid = seqid;
        p->res.seqid = seqid;
-       p->res.seq_res.sr_slotid = NFS4_MAX_SLOT_TABLE;
        p->arg.stateid = &lsp->ls_stateid;
        p->lsp = lsp;
        atomic_inc(&lsp->ls_count);
@@ -3979,7 +3973,6 @@ static struct nfs4_lockdata *nfs4_alloc_lockdata(struct file_lock *fl,
        p->arg.lock_owner.clientid = server->nfs_client->cl_clientid;
        p->arg.lock_owner.id = lsp->ls_id.id;
        p->res.lock_seqid = p->arg.lock_seqid;
-       p->res.seq_res.sr_slotid = NFS4_MAX_SLOT_TABLE;
        p->lsp = lsp;
        p->server = server;
        atomic_inc(&lsp->ls_count);
@@ -4612,7 +4605,6 @@ int nfs4_proc_get_lease_time(struct nfs_client *clp, struct nfs_fsinfo *fsinfo)
        };
        int status;
 
-       res.lr_seq_res.sr_slotid = NFS4_MAX_SLOT_TABLE;
        dprintk("--> %s\n", __func__);
        task = rpc_run_task(&task_setup);
 
@@ -5105,12 +5097,11 @@ static struct rpc_task *_nfs41_proc_sequence(struct nfs_client *clp, struct rpc_
 
        if (!atomic_inc_not_zero(&clp->cl_count))
                return ERR_PTR(-EIO);
-       calldata = kmalloc(sizeof(*calldata), GFP_NOFS);
+       calldata = kzalloc(sizeof(*calldata), GFP_NOFS);
        if (calldata == NULL) {
                nfs_put_client(clp);
                return ERR_PTR(-ENOMEM);
        }
-       calldata->res.sr_slotid = NFS4_MAX_SLOT_TABLE;
        msg.rpc_argp = &calldata->args;
        msg.rpc_resp = &calldata->res;
        calldata->clp = clp;
@@ -5242,7 +5233,6 @@ static int nfs41_proc_reclaim_complete(struct nfs_client *clp)
                goto out;
        calldata->clp = clp;
        calldata->arg.one_fs = 0;
-       calldata->res.seq_res.sr_slotid = NFS4_MAX_SLOT_TABLE;
 
        msg.rpc_argp = &calldata->arg;
        msg.rpc_resp = &calldata->res;

diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c
index 86ab69e..3feace6 100644 (file)
--- a/fs/nfs/nfs4xdr.c
+++ b/fs/nfs/nfs4xdr.c
@@ -4665,7 +4665,6 @@ static int decode_sequence(struct xdr_stream *xdr,
                           struct rpc_rqst *rqstp)
 {
 #if defined(CONFIG_NFS_V4_1)
-       struct nfs4_slot *slot;
        struct nfs4_sessionid id;
        u32 dummy;
        int status;
@@ -4697,15 +4696,14 @@ static int decode_sequence(struct xdr_stream *xdr,
                goto out_overflow;
 
        /* seqid */
-       slot = &res->sr_session->fc_slot_table.slots[res->sr_slotid];
        dummy = be32_to_cpup(p++);
-       if (dummy != slot->seq_nr) {
+       if (dummy != res->sr_slot->seq_nr) {
                dprintk("%s Invalid sequence number\n", __func__);
                goto out_err;
        }
        /* slot id */
        dummy = be32_to_cpup(p++);
-       if (dummy != res->sr_slotid) {
+       if (dummy != res->sr_slot - res->sr_session->fc_slot_table.slots) {
                dprintk("%s Invalid slot id\n", __func__);
                goto out_err;
        }

diff --git a/fs/nfs/read.c b/fs/nfs/read.c
index 87adc27..79859c8 100644 (file)
--- a/fs/nfs/read.c
+++ b/fs/nfs/read.c
@@ -46,7 +46,6 @@ struct nfs_read_data *nfs_readdata_alloc(unsigned int pagecount)
                memset(p, 0, sizeof(*p));
                INIT_LIST_HEAD(&p->pages);
                p->npages = pagecount;
-               p->res.seq_res.sr_slotid = NFS4_MAX_SLOT_TABLE;
                if (pagecount <= ARRAY_SIZE(p->page_array))
                        p->pagevec = p->page_array;
                else {

diff --git a/fs/nfs/unlink.c b/fs/nfs/unlink.c
index 47530aa..9a16bad 100644 (file)
--- a/fs/nfs/unlink.c
+++ b/fs/nfs/unlink.c
@@ -262,7 +262,6 @@ nfs_async_unlink(struct inode *dir, struct dentry *dentry)
                status = PTR_ERR(data->cred);
                goto out_free;
        }
-       data->res.seq_res.sr_slotid = NFS4_MAX_SLOT_TABLE;
        data->res.dir_attr = &data->dir_attr;
 
        status = -EBUSY;
@@ -427,7 +426,7 @@ nfs_async_rename(struct inode *old_dir, struct inode *new_dir,
                .flags = RPC_TASK_ASYNC,
        };
 
-       data = kmalloc(sizeof(*data), GFP_KERNEL);
+       data = kzalloc(sizeof(*data), GFP_KERNEL);
        if (data == NULL)
                return ERR_PTR(-ENOMEM);
        task_setup_data.callback_data = data,

diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index 874972d..4d6d35d 100644 (file)
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -55,7 +55,6 @@ struct nfs_write_data *nfs_commitdata_alloc(void)
        if (p) {
                memset(p, 0, sizeof(*p));
                INIT_LIST_HEAD(&p->pages);
-               p->res.seq_res.sr_slotid = NFS4_MAX_SLOT_TABLE;
        }
        return p;
 }
@@ -75,7 +74,6 @@ struct nfs_write_data *nfs_writedata_alloc(unsigned int pagecount)
                memset(p, 0, sizeof(*p));
                INIT_LIST_HEAD(&p->pages);
                p->npages = pagecount;
-               p->res.seq_res.sr_slotid = NFS4_MAX_SLOT_TABLE;
                if (pagecount <= ARRAY_SIZE(p->page_array))
                        p->pagevec = p->page_array;
                else {

diff --git a/include/linux/nfs_xdr.h b/include/linux/nfs_xdr.h
index 172df83..5772b2c 100644 (file)
--- a/include/linux/nfs_xdr.h
+++ b/include/linux/nfs_xdr.h
@@ -170,7 +170,7 @@ struct nfs4_sequence_args {
 
 struct nfs4_sequence_res {
        struct nfs4_session     *sr_session;
-       u8                      sr_slotid;      /* slot used to send request */
+       struct nfs4_slot        *sr_slot;       /* slot used to send request */
        int                     sr_status;      /* sequence operation status */
        unsigned long           sr_renewal_time;
        u32                     sr_status_flags;