[PATCH 4.4 298/342] NFSv4: Fix a dentry leak on alias use

From: Greg Kroah-Hartman
Date: Tue Mar 01 2016 - 19:14:57 EST


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

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

From: Benjamin Coddington <bcodding@xxxxxxxxxx>

commit d9dfd8d741683347ee159d25f5b50c346a0df557 upstream.

In the case where d_add_unique() finds an appropriate alias to use it will
have already incremented the reference count. An additional dget() to swap
the open context's dentry is unnecessary and will leak a reference.

Signed-off-by: Benjamin Coddington <bcodding@xxxxxxxxxx>
Fixes: 275bb307865a3 ("NFSv4: Move dentry instantiation into the NFSv4-...")
Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
fs/nfs/nfs4proc.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -2461,9 +2461,9 @@ static int _nfs4_open_and_get_state(stru
dentry = d_add_unique(dentry, igrab(state->inode));
if (dentry == NULL) {
dentry = opendata->dentry;
- } else if (dentry != ctx->dentry) {
+ } else {
dput(ctx->dentry);
- ctx->dentry = dget(dentry);
+ ctx->dentry = dentry;
}
nfs_set_verifier(dentry,
nfs_save_change_attribute(d_inode(opendata->dir)));