fs: fix do_last error case when need_reval_dot

When open(2) without O_DIRECTORY opens an existing dir, it should return
EISDIR. In do_last(), the variable 'error' is initialized EISDIR, but it
is changed by d_revalidate() which returns any positive to represent
'the target dir is valid.'

Should we keep and return the initialized 'error' in this case.

Signed-off-by: Nick Piggin <npiggin@kernel.dk>

diff --git a/fs/namei.c b/fs/namei.c
index 14c73ed..bc24894 100644 (file)
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2122,11 +2122,13 @@ static struct file *do_last(struct nameidata *nd, struct path *path,
                dir = nd->path.dentry;
        case LAST_DOT:
                if (need_reval_dot(dir)) {
-                       error = d_revalidate(nd->path.dentry, nd);
-                       if (!error)
-                               error = -ESTALE;
-                       if (error < 0)
+                       int status = d_revalidate(nd->path.dentry, nd);
+                       if (!status)
+                               status = -ESTALE;
+                       if (status < 0) {
+                               error = status;
                                goto exit;
+                       }
                }
                /* fallthrough */
        case LAST_ROOT: