NFS: Ensure that we free the rpc_task after read and write cleanups are done
This patch ensures that we free the rpc_task after the cleanup callbacks
are done in order to avoid a deadlock problem that can be triggered if
the callback needs to wait for another workqueue item to complete.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: Weston Andros Adamson <dros@netapp.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Bruce Fields <bfields@fieldses.org>
Cc: stable@vger.kernel.org [>= 3.5]
diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index b673be3..c483cc5 100644
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -126,12 +126,16 @@
put_nfs_open_context(wdata->args.context);
if (wdata->pages.pagevec != wdata->pages.page_array)
kfree(wdata->pages.pagevec);
- if (wdata != &write_header->rpc_data)
- kfree(wdata);
- else
+ if (wdata == &write_header->rpc_data) {
wdata->header = NULL;
+ wdata = NULL;
+ }
if (atomic_dec_and_test(&hdr->refcnt))
hdr->completion_ops->completion(hdr);
+ /* Note: we only free the rpc_task after callbacks are done.
+ * See the comment in rpc_free_task() for why
+ */
+ kfree(wdata);
}
EXPORT_SYMBOL_GPL(nfs_writedata_release);