NFSv4.1: filelayout async error handler

Use our own async error handler.
Mark the layout as failed and retry i/o through the MDS on specified errors.

Update the mds_offset in nfs_readpage_retry so that a failed short-read retry
to a DS gets correctly resent through the MDS.

Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

5 files changed, 113 insertions, 6 deletions

diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
index 5e9df992cd73..1a3228e9ea22 100644
--- a/fs/nfs/internal.h
+++ b/fs/nfs/internal.h
@@ -285,6 +285,7 @@ extern int nfs_migrate_page(struct address_space *,
 #endif
 
 /* nfs4proc.c */
+extern void nfs4_reset_read(struct rpc_task *task, struct nfs_read_data *data);
 extern int nfs4_init_client(struct nfs_client *clp,
                             const struct rpc_timeout *timeparms,
                             const char *ip_addr,
diff --git a/fs/nfs/nfs4filelayout.c b/fs/nfs/nfs4filelayout.c
index 3608411653dc..6a424c19abea 100644
--- a/fs/nfs/nfs4filelayout.c
+++ b/fs/nfs/nfs4filelayout.c
@@ -40,6 +40,8 @@ MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Dean Hildebrand <dhildebz@umich.edu>");
 MODULE_DESCRIPTION("The NFSv4 file layout driver");
 
+#define FILELAYOUT_POLL_RETRY_MAX     (15*HZ)
+
 static int
 filelayout_set_layoutdriver(struct nfs_server *nfss)
 {
@@ -100,6 +102,83 @@ filelayout_get_dserver_offset(struct pnfs_layout_segment *lseg, loff_t offset)
         BUG();
 }
 
+/* For data server errors we don't recover from */
+static void
+filelayout_set_lo_fail(struct pnfs_layout_segment *lseg)
+{
+        if (lseg->pls_range.iomode == IOMODE_RW) {
+                dprintk("%s Setting layout IOMODE_RW fail bit\n", __func__);
+                set_bit(lo_fail_bit(IOMODE_RW), &lseg->pls_layout->plh_flags);
+        } else {
+                dprintk("%s Setting layout IOMODE_READ fail bit\n", __func__);
+                set_bit(lo_fail_bit(IOMODE_READ), &lseg->pls_layout->plh_flags);
+        }
+}
+
+static int filelayout_async_handle_error(struct rpc_task *task,
+                                         struct nfs4_state *state,
+                                         struct nfs_client *clp,
+                                         int *reset)
+{
+        if (task->tk_status >= 0)
+                return 0;
+
+        *reset = 0;
+
+        switch (task->tk_status) {
+        case -NFS4ERR_BADSESSION:
+        case -NFS4ERR_BADSLOT:
+        case -NFS4ERR_BAD_HIGH_SLOT:
+        case -NFS4ERR_DEADSESSION:
+        case -NFS4ERR_CONN_NOT_BOUND_TO_SESSION:
+        case -NFS4ERR_SEQ_FALSE_RETRY:
+        case -NFS4ERR_SEQ_MISORDERED:
+                dprintk("%s ERROR %d, Reset session. Exchangeid "
+                        "flags 0x%x\n", __func__, task->tk_status,
+                        clp->cl_exchange_flags);
+                nfs4_schedule_session_recovery(clp->cl_session);
+                break;
+        case -NFS4ERR_DELAY:
+        case -NFS4ERR_GRACE:
+        case -EKEYEXPIRED:
+                rpc_delay(task, FILELAYOUT_POLL_RETRY_MAX);
+                break;
+        default:
+                dprintk("%s DS error. Retry through MDS %d\n", __func__,
+                        task->tk_status);
+                *reset = 1;
+                break;
+        }
+        task->tk_status = 0;
+        return -EAGAIN;
+}
+
+/* NFS_PROTO call done callback routines */
+
+static int filelayout_read_done_cb(struct rpc_task *task,
+                                struct nfs_read_data *data)
+{
+        struct nfs_client *clp = data->ds_clp;
+        int reset = 0;
+
+        dprintk("%s DS read\n", __func__);
+
+        if (filelayout_async_handle_error(task, data->args.context->state,
+                                          data->ds_clp, &reset) == -EAGAIN) {
+                dprintk("%s calling restart ds_clp %p ds_clp->cl_session %p\n",
+                        __func__, data->ds_clp, data->ds_clp->cl_session);
+                if (reset) {
+                        filelayout_set_lo_fail(data->lseg);
+                        nfs4_reset_read(task, data);
+                        clp = NFS_SERVER(data->inode)->nfs_client;
+                }
+                nfs_restart_rpc(task, clp);
+                return -EAGAIN;
+        }
+
+        return 0;
+}
+
 /*
  * Call ops for the async read/write cases
  * In the case of dense layouts, the offset needs to be reset to its
@@ -109,6 +188,8 @@ static void filelayout_read_prepare(struct rpc_task *task, void *data)
 {
         struct nfs_read_data *rdata = (struct nfs_read_data *)data;
 
+        rdata->read_done_cb = filelayout_read_done_cb;
+
         if (nfs41_setup_sequence(rdata->ds_clp->cl_session,
                                 &rdata->args.seq_args, &rdata->res.seq_res,
                                 0, task))
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index d09623933302..1dc809039448 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -3074,15 +3074,10 @@ static int nfs4_proc_pathconf(struct nfs_server *server, struct nfs_fh *fhandle,
         return err;
 }
 
-static int nfs4_read_done(struct rpc_task *task, struct nfs_read_data *data)
+static int nfs4_read_done_cb(struct rpc_task *task, struct nfs_read_data *data)
 {
         struct nfs_server *server = NFS_SERVER(data->inode);
 
-        dprintk("--> %s\n", __func__);
-
-        if (!nfs4_sequence_done(task, &data->res.seq_res))
-                return -EAGAIN;
-
         if (nfs4_async_handle_error(task, server, data->args.context->state) == -EAGAIN) {
                 nfs_restart_rpc(task, server->nfs_client);
                 return -EAGAIN;
@@ -3094,12 +3089,40 @@ static int nfs4_read_done(struct rpc_task *task, struct nfs_read_data *data)
         return 0;
 }
 
+static int nfs4_read_done(struct rpc_task *task, struct nfs_read_data *data)
+{
+
+        dprintk("--> %s\n", __func__);
+
+        if (!nfs4_sequence_done(task, &data->res.seq_res))
+                return -EAGAIN;
+
+        return data->read_done_cb(task, data);
+}
+
 static void nfs4_proc_read_setup(struct nfs_read_data *data, struct rpc_message *msg)
 {
         data->timestamp   = jiffies;
+        data->read_done_cb = nfs4_read_done_cb;
         msg->rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_READ];
 }
 
+/* Reset the the nfs_read_data to send the read to the MDS. */
+void nfs4_reset_read(struct rpc_task *task, struct nfs_read_data *data)
+{
+        dprintk("%s Reset task for i/o through\n", __func__);
+        put_lseg(data->lseg);
+        data->lseg = NULL;
+        /* offsets will differ in the dense stripe case */
+        data->args.offset = data->mds_offset;
+        data->ds_clp = NULL;
+        data->args.fh     = NFS_FH(data->inode);
+        data->read_done_cb = nfs4_read_done_cb;
+        task->tk_ops = data->mds_ops;
+        rpc_task_reset_client(task, NFS_CLIENT(data->inode));
+}
+EXPORT_SYMBOL_GPL(nfs4_reset_read);
+
 static int nfs4_write_done(struct rpc_task *task, struct nfs_write_data *data)
 {
         struct inode *inode = data->inode;
diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c
index 69c836373124..ab1bf5bb021f 100644
--- a/fs/nfs/nfs4state.c
+++ b/fs/nfs/nfs4state.c
@@ -1453,6 +1453,7 @@ void nfs4_schedule_session_recovery(struct nfs4_session *session)
 {
         nfs4_schedule_lease_recovery(session->clp);
 }
+EXPORT_SYMBOL_GPL(nfs4_schedule_session_recovery);
 
 void nfs41_handle_recall_slot(struct nfs_client *clp)
 {
diff --git a/fs/nfs/read.c b/fs/nfs/read.c
index f4d0fcffcb5a..f40c7f4dc16b 100644
--- a/fs/nfs/read.c
+++ b/fs/nfs/read.c
@@ -391,6 +391,7 @@ static void nfs_readpage_retry(struct rpc_task *task, struct nfs_read_data *data
                 return;
 
         /* Yes, so retry the read at the end of the data */
+        data->mds_offset += resp->count;
         argp->offset += resp->count;
         argp->pgbase += resp->count;
         argp->count -= resp->count;