[PATCH 5.10 103/104] ovl: expand warning in ovl_d_real()

Greg Kroah-Hartman
2021-02-15T16:05:03Z

From: Miklos Szeredi <mszeredi@redhat.com>

commit cef4cbff06fbc3be54d6d79ee139edecc2ee8598 upstream.

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

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
fs/overlayfs/super.c | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)

--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -79,7 +79,7 @@ static void ovl_dentry_release(struct de
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
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
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;
}