NFS: Ensure that the read code cleans up properly when rpc_run_task() fails

In the case of readpage() we need to ensure that the pages get unlocked,
and that the error is flagged.

In the case of O_DIRECT, we need to ensure that the pages are all released.

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

2 files changed, 46 insertions, 26 deletions

diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c
index e44200579c8..9d9085b93a3 100644
--- a/fs/nfs/direct.c
+++ b/fs/nfs/direct.c
@@ -229,14 +229,20 @@ static void nfs_direct_complete(struct nfs_direct_req *dreq)
 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 (nfs_readpage_result(task, data) != 0)
-                return;
+        nfs_readpage_result(task, data);
+}
+
+static void nfs_direct_read_release(void *calldata)
+{
+
+        struct nfs_read_data *data = calldata;
+        struct nfs_direct_req *dreq = (struct nfs_direct_req *) data->req;
+        int status = data->task.tk_status;
 
         spin_lock(&dreq->lock);
-        if (unlikely(task->tk_status < 0)) {
-                dreq->error = task->tk_status;
+        if (unlikely(status < 0)) {
+                dreq->error = status;
                 spin_unlock(&dreq->lock);
         } else {
                 dreq->count += data->res.count;
@@ -249,11 +255,12 @@ static void nfs_direct_read_result(struct rpc_task *task, void *calldata)
 
         if (put_dreq(dreq))
                 nfs_direct_complete(dreq);
+        nfs_readdata_release(calldata);
 }
 
 static const struct rpc_call_ops nfs_read_direct_ops = {
         .rpc_call_done = nfs_direct_read_result,
-        .rpc_release = nfs_readdata_release,
+        .rpc_release = nfs_direct_read_release,
 };
 
 /*
diff --git a/fs/nfs/read.c b/fs/nfs/read.c
index d333f5fedca..6f9208a549a 100644
--- a/fs/nfs/read.c
+++ b/fs/nfs/read.c
@@ -338,26 +338,25 @@ int nfs_readpage_result(struct rpc_task *task, struct nfs_read_data *data)
         return 0;
 }
 
-static int nfs_readpage_retry(struct rpc_task *task, struct nfs_read_data *data)
+static void nfs_readpage_retry(struct rpc_task *task, struct nfs_read_data *data)
 {
         struct nfs_readargs *argp = &data->args;
         struct nfs_readres *resp = &data->res;
 
         if (resp->eof || resp->count == argp->count)
-                return 0;
+                return;
 
         /* This is a short read! */
         nfs_inc_stats(data->inode, NFSIOS_SHORTREAD);
         /* Has the server at least made some progress? */
         if (resp->count == 0)
-                return 0;
+                return;
 
         /* Yes, so retry the read at the end of the data */
         argp->offset += resp->count;
         argp->pgbase += resp->count;
         argp->count -= resp->count;
         rpc_restart_call(task);
-        return -EAGAIN;
 }
 
 /*
@@ -366,29 +365,37 @@ static int nfs_readpage_retry(struct rpc_task *task, struct nfs_read_data *data)
 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 (nfs_readpage_result(task, data) != 0)
                 return;
+        if (task->tk_status < 0)
+                return;
 
-        if (likely(task->tk_status >= 0)) {
-                nfs_readpage_truncate_uninitialised_page(data);
-                if (nfs_readpage_retry(task, data) != 0)
-                        return;
-        }
-        if (unlikely(task->tk_status < 0))
+        nfs_readpage_truncate_uninitialised_page(data);
+        nfs_readpage_retry(task, data);
+}
+
+static void nfs_readpage_release_partial(void *calldata)
+{
+        struct nfs_read_data *data = calldata;
+        struct nfs_page *req = data->req;
+        struct page *page = req->wb_page;
+        int status = data->task.tk_status;
+
+        if (status < 0)
                 SetPageError(page);
+
         if (atomic_dec_and_test(&req->wb_complete)) {
                 if (!PageError(page))
                         SetPageUptodate(page);
                 nfs_readpage_release(req);
         }
+        nfs_readdata_release(calldata);
 }
 
 static const struct rpc_call_ops nfs_read_partial_ops = {
         .rpc_call_done = nfs_readpage_result_partial,
-        .rpc_release = nfs_readdata_release,
+        .rpc_release = nfs_readpage_release_partial,
 };
 
 static void nfs_readpage_set_pages_uptodate(struct nfs_read_data *data)
@@ -423,29 +430,35 @@ static void nfs_readpage_result_full(struct rpc_task *task, void *calldata)
 
         if (nfs_readpage_result(task, data) != 0)
                 return;
+        if (task->tk_status < 0)
+                return;
         /*
          * Note: nfs_readpage_retry may change the values of
          * data->args. In the multi-page case, we therefore need
          * to ensure that we call nfs_readpage_set_pages_uptodate()
          * first.
          */
-        if (likely(task->tk_status >= 0)) {
-                nfs_readpage_truncate_uninitialised_page(data);
-                nfs_readpage_set_pages_uptodate(data);
-                if (nfs_readpage_retry(task, data) != 0)
-                        return;
-        }
+        nfs_readpage_truncate_uninitialised_page(data);
+        nfs_readpage_set_pages_uptodate(data);
+        nfs_readpage_retry(task, data);
+}
+
+static void nfs_readpage_release_full(void *calldata)
+{
+        struct nfs_read_data *data = calldata;
+
         while (!list_empty(&data->pages)) {
                 struct nfs_page *req = nfs_list_entry(data->pages.next);
 
                 nfs_list_remove_request(req);
                 nfs_readpage_release(req);
         }
+        nfs_readdata_release(calldata);
 }
 
 static const struct rpc_call_ops nfs_read_full_ops = {
         .rpc_call_done = nfs_readpage_result_full,
-        .rpc_release = nfs_readdata_release,
+        .rpc_release = nfs_readpage_release_full,
 };
 
 /*