NFS: Cleanup of NFS write code in preparation for asynchronous o_direct

This patch inverts the callback hierarchy for NFS write calls.

Instead of having the NFSv2/v3/v4-specific code set up the RPC callback
ops, we allow the original caller to do so. This allows for more
flexibility w.r.t. how to set up and tear down the nfs_write_data
structure while still allowing the NFSv3/v4 code to perform error
handling.

The greater flexibility is needed by the asynchronous O_DIRECT code, which
wants to be able to hold on to the original nfs_write_data structures after
the WRITE RPC call has completed in order to be able to replay them if the
COMMIT call determines that the server has rebooted.

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

1 files changed, 17 insertions, 49 deletions

diff --git a/fs/nfs/nfs3proc.c b/fs/nfs/nfs3proc.c
index 740f8b1ab04d..c4f7de8830e9 100644
--- a/fs/nfs/nfs3proc.c
+++ b/fs/nfs/nfs3proc.c
@@ -849,29 +849,17 @@ nfs3_proc_read_setup(struct nfs_read_data *data)
         rpc_call_setup(task, &msg, 0);
 }
 
-static void nfs3_write_done(struct rpc_task *task, void *calldata)
+static int nfs3_write_done(struct rpc_task *task, struct nfs_write_data *data)
 {
-        struct nfs_write_data *data = calldata;
-
         if (nfs3_async_handle_jukebox(task, data->inode))
-                return;
+                return -EAGAIN;
         if (task->tk_status >= 0)
                 nfs_post_op_update_inode(data->inode, data->res.fattr);
-        nfs_writeback_done(task, calldata);
+        return 0;
 }
 
-static const struct rpc_call_ops nfs3_write_ops = {
-        .rpc_call_done = nfs3_write_done,
-        .rpc_release = nfs_writedata_release,
-};
-
-static void
-nfs3_proc_write_setup(struct nfs_write_data *data, int how)
+static void nfs3_proc_write_setup(struct nfs_write_data *data, int how)
 {
-        struct rpc_task         *task = &data->task;
-        struct inode            *inode = data->inode;
-        int                     stable;
-        int                     flags;
         struct rpc_message      msg = {
                 .rpc_proc       = &nfs3_procedures[NFS3PROC_WRITE],
                 .rpc_argp       = &data->args,
@@ -879,45 +867,28 @@ nfs3_proc_write_setup(struct nfs_write_data *data, int how)
                 .rpc_cred       = data->cred,
         };
 
+        data->args.stable = NFS_UNSTABLE;
         if (how & FLUSH_STABLE) {
-                if (!NFS_I(inode)->ncommit)
-                        stable = NFS_FILE_SYNC;
-                else
-                        stable = NFS_DATA_SYNC;
-        } else
-                stable = NFS_UNSTABLE;
-        data->args.stable = stable;
-
-        /* Set the initial flags for the task.  */
-        flags = (how & FLUSH_SYNC) ? 0 : RPC_TASK_ASYNC;
+                data->args.stable = NFS_FILE_SYNC;
+                if (NFS_I(data->inode)->ncommit)
+                        data->args.stable = NFS_DATA_SYNC;
+        }
 
         /* Finalize the task. */
-        rpc_init_task(task, NFS_CLIENT(inode), flags, &nfs3_write_ops, data);
-        rpc_call_setup(task, &msg, 0);
+        rpc_call_setup(&data->task, &msg, 0);
 }
 
-static void nfs3_commit_done(struct rpc_task *task, void *calldata)
+static int nfs3_commit_done(struct rpc_task *task, struct nfs_write_data *data)
 {
-        struct nfs_write_data *data = calldata;
-
         if (nfs3_async_handle_jukebox(task, data->inode))
-                return;
+                return -EAGAIN;
         if (task->tk_status >= 0)
                 nfs_post_op_update_inode(data->inode, data->res.fattr);
-        nfs_commit_done(task, calldata);
+        return 0;
 }
 
-static const struct rpc_call_ops nfs3_commit_ops = {
-        .rpc_call_done = nfs3_commit_done,
-        .rpc_release = nfs_commit_release,
-};
-
-static void
-nfs3_proc_commit_setup(struct nfs_write_data *data, int how)
+static void nfs3_proc_commit_setup(struct nfs_write_data *data, int how)
 {
-        struct rpc_task         *task = &data->task;
-        struct inode            *inode = data->inode;
-        int                     flags;
         struct rpc_message      msg = {
                 .rpc_proc       = &nfs3_procedures[NFS3PROC_COMMIT],
                 .rpc_argp       = &data->args,
@@ -925,12 +896,7 @@ nfs3_proc_commit_setup(struct nfs_write_data *data, int how)
                 .rpc_cred       = data->cred,
         };
 
-        /* Set the initial flags for the task.  */
-        flags = (how & FLUSH_SYNC) ? 0 : RPC_TASK_ASYNC;
-
-        /* Finalize the task. */
-        rpc_init_task(task, NFS_CLIENT(inode), flags, &nfs3_commit_ops, data);
-        rpc_call_setup(task, &msg, 0);
+        rpc_call_setup(&data->task, &msg, 0);
 }
 
 static int
@@ -970,7 +936,9 @@ struct nfs_rpc_ops	nfs_v3_clientops = {
         .decode_dirent  = nfs3_decode_dirent,
         .read_setup     = nfs3_proc_read_setup,
         .write_setup    = nfs3_proc_write_setup,
+        .write_done     = nfs3_write_done,
         .commit_setup   = nfs3_proc_commit_setup,
+        .commit_done    = nfs3_commit_done,
         .file_open      = nfs_open,
         .file_release   = nfs_release,
         .lock           = nfs3_proc_lock,