ovl: expand warning in ovl_d_real()

There was a syzbot report with this warning but insufficient information...

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index 4717244..8cd6a45 100644 (file)
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -79,7 +79,7 @@ static void ovl_dentry_release(struct dentry *dentry)
 static struct dentry *ovl_d_real(struct dentry *dentry,
                                 const struct inode *inode)
 {
-       struct dentry *real;
+       struct dentry *real = NULL, *lower;
 
        /* It's an overlay file */
        if (inode && d_inode(dentry) == inode)
@@ -98,9 +98,10 @@ static struct dentry *ovl_d_real(struct dentry *dentry,
        if (real && !inode && ovl_has_upperdata(d_inode(dentry)))
                return real;
 
-       real = ovl_dentry_lowerdata(dentry);
-       if (!real)
+       lower = ovl_dentry_lowerdata(dentry);
+       if (!lower)
                goto bug;
+       real = lower;
 
        /* Handle recursion */
        real = d_real(real, inode);
@@ -108,8 +109,10 @@ static struct dentry *ovl_d_real(struct dentry *dentry,
        if (!inode || inode == d_inode(real))
                return real;
 bug:
-       WARN(1, "ovl_d_real(%pd4, %s:%lu): real dentry not found\n", dentry,
-            inode ? inode->i_sb->s_id : "NULL", inode ? inode->i_ino : 0);
+       WARN(1, "%s(%pd4, %s:%lu): real dentry (%p/%lu) not found\n",
+            __func__, dentry, inode ? inode->i_sb->s_id : "NULL",
+            inode ? inode->i_ino : 0, real,
+            real && d_inode(real) ? d_inode(real)->i_ino : 0);
        return dentry;
 }