NFSv4: Fix a dentry leak on alias use

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@redhat.com>
Fixes: 275bb307865a3 ("NFSv4: Move dentry instantiation into the NFSv4-...")
Cc: stable@vger.kernel.org # 3.10+
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 4bfc33a..1488159 100644 (file)
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -2466,9 +2466,9 @@ static int _nfs4_open_and_get_state(struct nfs4_opendata *opendata,
                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)));