pnfs: support for non-rpc layout drivers

Non-rpc layout driver such as for objects and blocks
implement their own I/O path and error handling logic.
Therefore bypass NFS-based error handling for these layout drivers.

[fix lseg ref-count bugs, and null de-refs]
[Fall out from: non-rpc layout drivers]
Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
[get rid of PNFS_USE_RPC_CODE]
[get rid of __nfs4_write_done_cb]
[revert useless change in nfs4_write_done_cb]
Signed-off-by: Benny Halevy <bhalevy@panasas.com>

4 files changed, 60 insertions, 4 deletions

diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
index ce118ce885dd..bcf0f0ff5eeb 100644
--- a/fs/nfs/internal.h
+++ b/fs/nfs/internal.h
@@ -310,6 +310,7 @@ extern int nfs_migrate_page(struct address_space *,
 #endif
 
 /* nfs4proc.c */
+extern void __nfs4_read_done_cb(struct nfs_read_data *);
 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,
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index cf1b339c3937..92c8bc4b5f97 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -3175,6 +3175,11 @@ static int nfs4_proc_pathconf(struct nfs_server *server, struct nfs_fh *fhandle,
         return err;
 }
 
+void __nfs4_read_done_cb(struct nfs_read_data *data)
+{
+        nfs_invalidate_atime(data->inode);
+}
+
 static int nfs4_read_done_cb(struct rpc_task *task, struct nfs_read_data *data)
 {
         struct nfs_server *server = NFS_SERVER(data->inode);
@@ -3184,7 +3189,7 @@ static int nfs4_read_done_cb(struct rpc_task *task, struct nfs_read_data *data)
                 return -EAGAIN;
         }
 
-        nfs_invalidate_atime(data->inode);
+        __nfs4_read_done_cb(data);
         if (task->tk_status > 0)
                 renew_lease(server, data->timestamp);
         return 0;
@@ -3198,7 +3203,8 @@ static int nfs4_read_done(struct rpc_task *task, struct nfs_read_data *data)
         if (!nfs4_sequence_done(task, &data->res.seq_res))
                 return -EAGAIN;
 
-        return data->read_done_cb(task, data);
+        return data->read_done_cb ? data->read_done_cb(task, data) :
+                                    nfs4_read_done_cb(task, data);
 }
 
 static void nfs4_proc_read_setup(struct nfs_read_data *data, struct rpc_message *msg)
@@ -3243,7 +3249,8 @@ static int nfs4_write_done(struct rpc_task *task, struct nfs_write_data *data)
 {
         if (!nfs4_sequence_done(task, &data->res.seq_res))
                 return -EAGAIN;
-        return data->write_done_cb(task, data);
+        return data->write_done_cb ? data->write_done_cb(task, data) :
+                nfs4_write_done_cb(task, data);
 }
 
 /* Reset the the nfs_write_data to send the write to the MDS. */
diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
index ef535f2a2c74..171662114fdd 100644
--- a/fs/nfs/pnfs.c
+++ b/fs/nfs/pnfs.c
@@ -243,7 +243,7 @@ put_lseg_common(struct pnfs_layout_segment *lseg)
 {
         struct inode *inode = lseg->pls_layout->plh_inode;
 
-        BUG_ON(test_bit(NFS_LSEG_VALID, &lseg->pls_flags));
+        WARN_ON(test_bit(NFS_LSEG_VALID, &lseg->pls_flags));
         list_del_init(&lseg->pls_list);
         if (list_empty(&lseg->pls_layout->plh_segs)) {
                 set_bit(NFS_LAYOUT_DESTROYED, &lseg->pls_layout->plh_flags);
@@ -1054,6 +1054,29 @@ pnfs_pageio_init_write(struct nfs_pageio_descriptor *pgio, struct inode *inode)
         pgio->pg_test = (ld && ld->pg_test) ? pnfs_write_pg_test : NULL;
 }
 
+/*
+ * Called by non rpc-based layout drivers
+ */
+int
+pnfs_ld_write_done(struct nfs_write_data *data)
+{
+        int status;
+
+        if (!data->pnfs_error) {
+                pnfs_set_layoutcommit(data);
+                data->mds_ops->rpc_call_done(&data->task, data);
+                data->mds_ops->rpc_release(data);
+                return 0;
+        }
+
+        dprintk("%s: pnfs_error=%d, retry via MDS\n", __func__,
+                data->pnfs_error);
+        status = nfs_initiate_write(data, NFS_CLIENT(data->inode),
+                                    data->mds_ops, NFS_FILE_SYNC);
+        return status ? : -EAGAIN;
+}
+EXPORT_SYMBOL_GPL(pnfs_ld_write_done);
+
 enum pnfs_try_status
 pnfs_try_to_write_data(struct nfs_write_data *wdata,
                         const struct rpc_call_ops *call_ops, int how)
@@ -1079,6 +1102,29 @@ pnfs_try_to_write_data(struct nfs_write_data *wdata,
 }
 
 /*
+ * Called by non rpc-based layout drivers
+ */
+int
+pnfs_ld_read_done(struct nfs_read_data *data)
+{
+        int status;
+
+        if (!data->pnfs_error) {
+                __nfs4_read_done_cb(data);
+                data->mds_ops->rpc_call_done(&data->task, data);
+                data->mds_ops->rpc_release(data);
+                return 0;
+        }
+
+        dprintk("%s: pnfs_error=%d, retry via MDS\n", __func__,
+                data->pnfs_error);
+        status = nfs_initiate_read(data, NFS_CLIENT(data->inode),
+                                   data->mds_ops);
+        return status ? : -EAGAIN;
+}
+EXPORT_SYMBOL_GPL(pnfs_ld_read_done);
+
+/*
  * Call the appropriate parallel I/O subsystem read function.
  */
 enum pnfs_try_status
diff --git a/fs/nfs/pnfs.h b/fs/nfs/pnfs.h
index 925d6ef8ba79..0383e66e71f0 100644
--- a/fs/nfs/pnfs.h
+++ b/fs/nfs/pnfs.h
@@ -165,6 +165,8 @@ void pnfs_roc_set_barrier(struct inode *ino, u32 barrier);
 bool pnfs_roc_drain(struct inode *ino, u32 *barrier);
 void pnfs_set_layoutcommit(struct nfs_write_data *wdata);
 int pnfs_layoutcommit_inode(struct inode *inode, bool sync);
+int pnfs_ld_write_done(struct nfs_write_data *);
+int pnfs_ld_read_done(struct nfs_read_data *);
 
 /* pnfs_dev.c */
 struct nfs4_deviceid_node {