nfs41: fix nfs4_proc_layoutget error handling

commit 4bd5a980de87d2b5af417485bde97b8eb3d6cf6a upstream.

nfs4_layoutget_release() drops layout hdr refcnt. Grab the refcnt
early so that it is safe to call .release in case nfs4_alloc_pages
fails.

Signed-off-by: Peng Tao <tao.peng@primarydata.com>
Fixes: a47970ff78147 ("NFSv4.1: Hold reference to layout hdr in layoutget")
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 78787948f69d75a7ff97a569fa707771ab027710..20ebcfa3c92ecd9760464d96d0cc7f133c10ccff 100644 (file)
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -6418,6 +6418,9 @@ nfs4_proc_layoutget(struct nfs4_layoutget *lgp, gfp_t gfp_flags)
 
        dprintk("--> %s\n", __func__);
 
+       /* nfs4_layoutget_release calls pnfs_put_layout_hdr */
+       pnfs_get_layout_hdr(NFS_I(inode)->layout);
+
        lgp->args.layout.pages = nfs4_alloc_pages(max_pages, gfp_flags);
        if (!lgp->args.layout.pages) {
                nfs4_layoutget_release(lgp);
@@ -6430,9 +6433,6 @@ nfs4_proc_layoutget(struct nfs4_layoutget *lgp, gfp_t gfp_flags)
        lgp->res.seq_res.sr_slot = NULL;
        nfs41_init_sequence(&lgp->args.seq_args, &lgp->res.seq_res, 0);
 
-       /* nfs4_layoutget_release calls pnfs_put_layout_hdr */
-       pnfs_get_layout_hdr(NFS_I(inode)->layout);
-
        task = rpc_run_task(&task_setup_data);
        if (IS_ERR(task))
                return ERR_CAST(task);