NFS: Cleanup of NFS read code

Same callback hierarchy inversion as for the NFS write calls. This patch is
not strictly speaking needed by the O_DIRECT code, but avoids confusing
differences between the asynchronous read and write code.

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

5 files changed, 74 insertions, 86 deletions

diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c
index fc07ce4885da..3f87a72bd137 100644
--- a/fs/nfs/direct.c
+++ b/fs/nfs/direct.c
@@ -218,14 +218,17 @@ static struct nfs_direct_req *nfs_direct_read_alloc(size_t nbytes, unsigned int
  * until the RPCs complete.  This could be long *after* we are woken up in
  * nfs_direct_read_wait (for instance, if someone hits ^C on a slow server).
  */
-static void nfs_direct_read_result(struct nfs_read_data *data, int status)
+static void nfs_direct_read_result(struct rpc_task *task, void *calldata)
 {
+        struct nfs_read_data *data = calldata;
         struct nfs_direct_req *dreq = (struct nfs_direct_req *) data->req;
 
-        if (likely(status >= 0))
+        if (nfs_readpage_result(task, data) != 0)
+                return;
+        if (likely(task->tk_status >= 0))
                 atomic_add(data->res.count, &dreq->count);
         else
-                atomic_set(&dreq->error, status);
+                atomic_set(&dreq->error, task->tk_status);
 
         if (unlikely(atomic_dec_and_test(&dreq->complete))) {
                 nfs_free_user_pages(dreq->pages, dreq->npages, 1);
@@ -234,6 +237,11 @@ static void nfs_direct_read_result(struct nfs_read_data *data, int status)
         }
 }
 
+static const struct rpc_call_ops nfs_read_direct_ops = {
+        .rpc_call_done = nfs_direct_read_result,
+        .rpc_release = nfs_readdata_release,
+};
+
 /**
  * nfs_direct_read_schedule - dispatch NFS READ operations for a direct read
  * @dreq: address of nfs_direct_req struct for this request
@@ -280,10 +288,11 @@ static void nfs_direct_read_schedule(struct nfs_direct_req *dreq,
                 data->res.eof = 0;
                 data->res.count = bytes;
 
+                rpc_init_task(&data->task, NFS_CLIENT(inode), RPC_TASK_ASYNC,
+                                &nfs_read_direct_ops, data);
                 NFS_PROTO(inode)->read_setup(data);
 
                 data->task.tk_cookie = (unsigned long) inode;
-                data->complete = nfs_direct_read_result;
 
                 lock_kernel();
                 rpc_execute(&data->task);
diff --git a/fs/nfs/nfs3proc.c b/fs/nfs/nfs3proc.c
index c4f7de8830e9..cf186f0d2b3b 100644
--- a/fs/nfs/nfs3proc.c
+++ b/fs/nfs/nfs3proc.c
@@ -811,29 +811,18 @@ nfs3_proc_pathconf(struct nfs_server *server, struct nfs_fh *fhandle,
 
 extern u32 *nfs3_decode_dirent(u32 *, struct nfs_entry *, int);
 
-static void nfs3_read_done(struct rpc_task *task, void *calldata)
+static int nfs3_read_done(struct rpc_task *task, struct nfs_read_data *data)
 {
-        struct nfs_read_data *data = calldata;
-
         if (nfs3_async_handle_jukebox(task, data->inode))
-                return;
+                return -EAGAIN;
         /* Call back common NFS readpage processing */
         if (task->tk_status >= 0)
                 nfs_refresh_inode(data->inode, &data->fattr);
-        nfs_readpage_result(task, calldata);
+        return 0;
 }
 
-static const struct rpc_call_ops nfs3_read_ops = {
-        .rpc_call_done = nfs3_read_done,
-        .rpc_release = nfs_readdata_release,
-};
-
-static void
-nfs3_proc_read_setup(struct nfs_read_data *data)
+static void nfs3_proc_read_setup(struct nfs_read_data *data)
 {
-        struct rpc_task         *task = &data->task;
-        struct inode            *inode = data->inode;
-        int                     flags;
         struct rpc_message      msg = {
                 .rpc_proc       = &nfs3_procedures[NFS3PROC_READ],
                 .rpc_argp       = &data->args,
@@ -841,12 +830,7 @@ nfs3_proc_read_setup(struct nfs_read_data *data)
                 .rpc_cred       = data->cred,
         };
 
-        /* N.B. Do we need to test? Never called for swapfile inode */
-        flags = RPC_TASK_ASYNC | (IS_SWAPFILE(inode)? NFS_RPC_SWAPFLAGS : 0);
-
-        /* Finalize the task. */
-        rpc_init_task(task, NFS_CLIENT(inode), flags, &nfs3_read_ops, data);
-        rpc_call_setup(task, &msg, 0);
+        rpc_call_setup(&data->task, &msg, 0);
 }
 
 static int nfs3_write_done(struct rpc_task *task, struct nfs_write_data *data)
@@ -935,6 +919,7 @@ struct nfs_rpc_ops	nfs_v3_clientops = {
         .pathconf       = nfs3_proc_pathconf,
         .decode_dirent  = nfs3_decode_dirent,
         .read_setup     = nfs3_proc_read_setup,
+        .read_done      = nfs3_read_done,
         .write_setup    = nfs3_proc_write_setup,
         .write_done     = nfs3_write_done,
         .commit_setup   = nfs3_proc_commit_setup,
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index ef4dc315ecc2..bad1eae5608a 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -2345,47 +2345,31 @@ static int nfs4_proc_pathconf(struct nfs_server *server, struct nfs_fh *fhandle,
         return err;
 }
 
-static void nfs4_read_done(struct rpc_task *task, void *calldata)
+static int nfs4_read_done(struct rpc_task *task, struct nfs_read_data *data)
 {
-        struct nfs_read_data *data = calldata;
-        struct inode *inode = data->inode;
+        struct nfs_server *server = NFS_SERVER(data->inode);
 
-        if (nfs4_async_handle_error(task, NFS_SERVER(inode)) == -EAGAIN) {
+        if (nfs4_async_handle_error(task, server) == -EAGAIN) {
                 rpc_restart_call(task);
-                return;
+                return -EAGAIN;
         }
         if (task->tk_status > 0)
-                renew_lease(NFS_SERVER(inode), data->timestamp);
-        /* Call back common NFS readpage processing */
-        nfs_readpage_result(task, calldata);
+                renew_lease(server, data->timestamp);
+        return 0;
 }
 
-static const struct rpc_call_ops nfs4_read_ops = {
-        .rpc_call_done = nfs4_read_done,
-        .rpc_release = nfs_readdata_release,
-};
-
-static void
-nfs4_proc_read_setup(struct nfs_read_data *data)
+static void nfs4_proc_read_setup(struct nfs_read_data *data)
 {
-        struct rpc_task *task = &data->task;
         struct rpc_message msg = {
                 .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_READ],
                 .rpc_argp = &data->args,
                 .rpc_resp = &data->res,
                 .rpc_cred = data->cred,
         };
-        struct inode *inode = data->inode;
-        int flags;
 
         data->timestamp   = jiffies;
 
-        /* N.B. Do we need to test? Never called for swapfile inode */
-        flags = RPC_TASK_ASYNC | (IS_SWAPFILE(inode)? NFS_RPC_SWAPFLAGS : 0);
-
-        /* Finalize the task. */
-        rpc_init_task(task, NFS_CLIENT(inode), flags, &nfs4_read_ops, data);
-        rpc_call_setup(task, &msg, 0);
+        rpc_call_setup(&data->task, &msg, 0);
 }
 
 static int nfs4_write_done(struct rpc_task *task, struct nfs_write_data *data)
@@ -3617,6 +3601,7 @@ struct nfs_rpc_ops	nfs_v4_clientops = {
         .pathconf       = nfs4_proc_pathconf,
         .decode_dirent  = nfs4_decode_dirent,
         .read_setup     = nfs4_proc_read_setup,
+        .read_done      = nfs4_read_done,
         .write_setup    = nfs4_proc_write_setup,
         .write_done     = nfs4_write_done,
         .commit_setup   = nfs4_proc_commit_setup,
diff --git a/fs/nfs/proc.c b/fs/nfs/proc.c
index 608aa5932a1d..9dd85cac2df0 100644
--- a/fs/nfs/proc.c
+++ b/fs/nfs/proc.c
@@ -613,10 +613,8 @@ nfs_proc_pathconf(struct nfs_server *server, struct nfs_fh *fhandle,
 
 extern u32 * nfs_decode_dirent(u32 *, struct nfs_entry *, int);
 
-static void nfs_read_done(struct rpc_task *task, void *calldata)
+static int nfs_read_done(struct rpc_task *task, struct nfs_read_data *data)
 {
-        struct nfs_read_data *data = calldata;
-
         if (task->tk_status >= 0) {
                 nfs_refresh_inode(data->inode, data->res.fattr);
                 /* Emulate the eof flag, which isn't normally needed in NFSv2
@@ -625,20 +623,11 @@ static void nfs_read_done(struct rpc_task *task, void *calldata)
                 if (data->args.offset + data->args.count >= data->res.fattr->size)
                         data->res.eof = 1;
         }
-        nfs_readpage_result(task, calldata);
+        return 0;
 }
 
-static const struct rpc_call_ops nfs_read_ops = {
-        .rpc_call_done = nfs_read_done,
-        .rpc_release = nfs_readdata_release,
-};
-
-static void
-nfs_proc_read_setup(struct nfs_read_data *data)
+static void nfs_proc_read_setup(struct nfs_read_data *data)
 {
-        struct rpc_task         *task = &data->task;
-        struct inode            *inode = data->inode;
-        int                     flags;
         struct rpc_message      msg = {
                 .rpc_proc       = &nfs_procedures[NFSPROC_READ],
                 .rpc_argp       = &data->args,
@@ -646,12 +635,7 @@ nfs_proc_read_setup(struct nfs_read_data *data)
                 .rpc_cred       = data->cred,
         };
 
-        /* N.B. Do we need to test? Never called for swapfile inode */
-        flags = RPC_TASK_ASYNC | (IS_SWAPFILE(inode)? NFS_RPC_SWAPFLAGS : 0);
-
-        /* Finalize the task. */
-        rpc_init_task(task, NFS_CLIENT(inode), flags, &nfs_read_ops, data);
-        rpc_call_setup(task, &msg, 0);
+        rpc_call_setup(&data->task, &msg, 0);
 }
 
 static int nfs_write_done(struct rpc_task *task, struct nfs_write_data *data)
@@ -720,6 +704,7 @@ struct nfs_rpc_ops	nfs_v2_clientops = {
         .pathconf       = nfs_proc_pathconf,
         .decode_dirent  = nfs_decode_dirent,
         .read_setup     = nfs_proc_read_setup,
+        .read_done      = nfs_read_done,
         .write_setup    = nfs_proc_write_setup,
         .write_done     = nfs_write_done,
         .commit_setup   = nfs_proc_commit_setup,
diff --git a/fs/nfs/read.c b/fs/nfs/read.c
index ae3ddd24cf8f..2da255f0247f 100644
--- a/fs/nfs/read.c
+++ b/fs/nfs/read.c
@@ -36,8 +36,8 @@
 #define NFSDBG_FACILITY         NFSDBG_PAGECACHE
 
 static int nfs_pagein_one(struct list_head *, struct inode *);
-static void nfs_readpage_result_partial(struct nfs_read_data *, int);
-static void nfs_readpage_result_full(struct nfs_read_data *, int);
+static const struct rpc_call_ops nfs_read_partial_ops;
+static const struct rpc_call_ops nfs_read_full_ops;
 
 static kmem_cache_t *nfs_rdata_cachep;
 mempool_t *nfs_rdata_mempool;
@@ -200,9 +200,11 @@ static void nfs_readpage_release(struct nfs_page *req)
  * Set up the NFS read request struct
  */
 static void nfs_read_rpcsetup(struct nfs_page *req, struct nfs_read_data *data,
+                const struct rpc_call_ops *call_ops,
                 unsigned int count, unsigned int offset)
 {
         struct inode            *inode;
+        int flags;
 
         data->req         = req;
         data->inode       = inode = req->wb_context->dentry->d_inode;
@@ -220,6 +222,9 @@ static void nfs_read_rpcsetup(struct nfs_page *req, struct nfs_read_data *data,
         data->res.eof     = 0;
         nfs_fattr_init(&data->fattr);
 
+        /* Set up the initial task struct. */
+        flags = RPC_TASK_ASYNC | (IS_SWAPFILE(inode)? NFS_RPC_SWAPFLAGS : 0);
+        rpc_init_task(&data->task, NFS_CLIENT(inode), flags, call_ops, data);
         NFS_PROTO(inode)->read_setup(data);
 
         data->task.tk_cookie = (unsigned long)inode;
@@ -307,14 +312,15 @@ static int nfs_pagein_multi(struct list_head *head, struct inode *inode)
                 list_del_init(&data->pages);
 
                 data->pagevec[0] = page;
-                data->complete = nfs_readpage_result_partial;
 
                 if (nbytes > rsize) {
-                        nfs_read_rpcsetup(req, data, rsize, offset);
+                        nfs_read_rpcsetup(req, data, &nfs_read_partial_ops,
+                                        rsize, offset);
                         offset += rsize;
                         nbytes -= rsize;
                 } else {
-                        nfs_read_rpcsetup(req, data, nbytes, offset);
+                        nfs_read_rpcsetup(req, data, &nfs_read_partial_ops,
+                                        nbytes, offset);
                         nbytes = 0;
                 }
                 nfs_execute_read(data);
@@ -360,8 +366,7 @@ static int nfs_pagein_one(struct list_head *head, struct inode *inode)
         }
         req = nfs_list_entry(data->pages.next);
 
-        data->complete = nfs_readpage_result_full;
-        nfs_read_rpcsetup(req, data, count, 0);
+        nfs_read_rpcsetup(req, data, &nfs_read_full_ops, count, 0);
 
         nfs_execute_read(data);
         return 0;
@@ -395,12 +400,15 @@ nfs_pagein_list(struct list_head *head, int rpages)
 /*
  * Handle a read reply that fills part of a page.
  */
-static void nfs_readpage_result_partial(struct nfs_read_data *data, int status)
+static void nfs_readpage_result_partial(struct rpc_task *task, void *calldata)
 {
+        struct nfs_read_data *data = calldata;
         struct nfs_page *req = data->req;
         struct page *page = req->wb_page;
  
-        if (status >= 0) {
+        if (nfs_readpage_result(task, data) != 0)
+                return;
+        if (task->tk_status >= 0) {
                 unsigned int request = data->args.count;
                 unsigned int result = data->res.count;
 
@@ -419,20 +427,28 @@ static void nfs_readpage_result_partial(struct nfs_read_data *data, int status)
         }
 }
 
+static const struct rpc_call_ops nfs_read_partial_ops = {
+        .rpc_call_done = nfs_readpage_result_partial,
+        .rpc_release = nfs_readdata_release,
+};
+
 /*
  * This is the callback from RPC telling us whether a reply was
  * received or some error occurred (timeout or socket shutdown).
  */
-static void nfs_readpage_result_full(struct nfs_read_data *data, int status)
+static void nfs_readpage_result_full(struct rpc_task *task, void *calldata)
 {
+        struct nfs_read_data *data = calldata;
         unsigned int count = data->res.count;
 
+        if (nfs_readpage_result(task, data) != 0)
+                return;
         while (!list_empty(&data->pages)) {
                 struct nfs_page *req = nfs_list_entry(data->pages.next);
                 struct page *page = req->wb_page;
                 nfs_list_remove_request(req);
 
-                if (status >= 0) {
+                if (task->tk_status >= 0) {
                         if (count < PAGE_CACHE_SIZE) {
                                 if (count < req->wb_bytes)
                                         memclear_highpage_flush(page,
@@ -448,19 +464,27 @@ static void nfs_readpage_result_full(struct nfs_read_data *data, int status)
         }
 }
 
+static const struct rpc_call_ops nfs_read_full_ops = {
+        .rpc_call_done = nfs_readpage_result_full,
+        .rpc_release = nfs_readdata_release,
+};
+
 /*
  * This is the callback from RPC telling us whether a reply was
  * received or some error occurred (timeout or socket shutdown).
  */
-void nfs_readpage_result(struct rpc_task *task, void *calldata)
+int nfs_readpage_result(struct rpc_task *task, struct nfs_read_data *data)
 {
-        struct nfs_read_data *data = calldata;
         struct nfs_readargs *argp = &data->args;
         struct nfs_readres *resp = &data->res;
-        int status = task->tk_status;
+        int status;
 
         dprintk("NFS: %4d nfs_readpage_result, (status %d)\n",
-                task->tk_pid, status);
+                task->tk_pid, task->tk_status);
+
+        status = NFS_PROTO(data->inode)->read_done(task, data);
+        if (status != 0)
+                return status;
 
         nfs_add_stats(data->inode, NFSIOS_SERVERREADBYTES, resp->count);
 
@@ -474,14 +498,14 @@ void nfs_readpage_result(struct rpc_task *task, void *calldata)
                         argp->pgbase += resp->count;
                         argp->count -= resp->count;
                         rpc_restart_call(task);
-                        return;
+                        return -EAGAIN;
                 }
                 task->tk_status = -EIO;
         }
         spin_lock(&data->inode->i_lock);
         NFS_I(data->inode)->cache_validity |= NFS_INO_INVALID_ATIME;
         spin_unlock(&data->inode->i_lock);
-        data->complete(data, status);
+        return 0;
 }
 
 /*