[PATCH 3.18 20/84] nfs41: fix nfs4_proc_layoutget error handling

[Greg Kroah-Hartman]

3.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Peng Tao <tao.peng@xxxxxxxxxxxxxxx>

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@xxxxxxxxxxxxxxx>
Fixes: a47970ff78147 ("NFSv4.1: Hold reference to layout hdr in layoutget")
Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 fs/nfs/nfs4proc.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -7704,6 +7704,9 @@ nfs4_proc_layoutget(struct nfs4_layoutge
 
 	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);
@@ -7716,9 +7719,6 @@ nfs4_proc_layoutget(struct nfs4_layoutge
 	lgp->res.seq_res.sr_slot = NULL;
 	nfs4_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);


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