From: Xin Xiong <xiongx18@fudan.edu.cn>
Date: Tue, 25 Jan 2022 21:10:45 +0800
Subject: [PATCH] NFSv4.2: fix reference count leaks in
 _nfs42_proc_copy_notify()
Git-commit: b7f114edd54326f730a754547e7cfb197b5bc132
Patch-mainline: v5.18
References: git-fixes

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The reference counting issue happens in two error paths in the
function _nfs42_proc_copy_notify(). In both error paths, the function
simply returns the error code and forgets to balance the refcount of
object `ctx`, bumped by get_nfs_open_context() earlier, which may
cause refcount leaks.

Fix it by balancing refcount of the `ctx` object before the function
returns in both error paths.

Signed-off-by: Xin Xiong <xiongx18@fudan.edu.cn>
Signed-off-by: Xiyu Yang <xiyuyang19@fudan.edu.cn>
Signed-off-by: Xin Tan <tanxin.ctf@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Acked-by: NeilBrown <neilb@suse.com>

---
 fs/nfs/nfs42proc.c |    9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

--- a/fs/nfs/nfs42proc.c
+++ b/fs/nfs/nfs42proc.c
@@ -591,8 +591,10 @@ static int _nfs42_proc_copy_notify(struc
 
 	ctx = get_nfs_open_context(nfs_file_open_context(src));
 	l_ctx = nfs_get_lock_context(ctx);
-	if (IS_ERR(l_ctx))
-		return PTR_ERR(l_ctx);
+	if (IS_ERR(l_ctx)) {
+		status = PTR_ERR(l_ctx);
+		goto out;
+	}
 
 	status = nfs4_set_rw_stateid(&args->cna_src_stateid, ctx, l_ctx,
 				     FMODE_READ);
@@ -600,7 +602,7 @@ static int _nfs42_proc_copy_notify(struc
 	if (status) {
 		if (status == -EAGAIN)
 			status = -NFS4ERR_BAD_STATEID;
-		return status;
+		goto out;
 	}
 
 	status = nfs4_call_sync(src_server->client, src_server, &msg,
@@ -608,6 +610,7 @@ static int _nfs42_proc_copy_notify(struc
 	if (status == -ENOTSUPP)
 		src_server->caps &= ~NFS_CAP_COPY_NOTIFY;
 
+out:
 	put_nfs_open_context(nfs_file_open_context(src));
 	return status;
 }