[PATCH AUTOSEL 5.6 117/129] ovl: fix value of i_ino for lower hardlink corner case

Sasha Levin
2020-04-15T12:55:38Z

From: Amir Goldstein <amir73il@gmail.com>

[ Upstream commit 300b124fcf6ad2cd99a7b721e0f096785e0a3134 ]

Commit 6dde1e42f497 ("ovl: make i_ino consistent with st_ino in more
cases"), relaxed the condition nfs_export=on in order to set the value of
i_ino to xino map of real ino.

Specifically, it also relaxed the pre-condition that index=on for
consistent i_ino. This opened the corner case of lower hardlink in
ovl_get_inode(), which calls ovl_fill_inode() with ino=0 and then
ovl_init_inode() is called to set i_ino to lower real ino without the xino
mapping.

Pass the correct values of ino;fsid in this case to ovl_fill_inode(), so it
can initialize i_ino correctly.

Fixes: 6dde1e42f497 ("ovl: make i_ino consistent with st_ino in more ...")
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/overlayfs/inode.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
index 79e8994e3bc1a..3f993c114829e 100644
--- a/fs/overlayfs/inode.c
+++ b/fs/overlayfs/inode.c
@@ -891,7 +891,7 @@ struct inode *ovl_get_inode(struct super_block *sb,
struct dentry *lowerdentry = lowerpath ? lowerpath->dentry : NULL;
bool bylower = ovl_hash_bylower(sb, upperdentry, lowerdentry,
oip->index);
- int fsid = bylower ? oip->lowerpath->layer->fsid : 0;
+ int fsid = bylower ? lowerpath->layer->fsid : 0;
bool is_dir, metacopy = false;
unsigned long ino = 0;
int err = oip->newinode ? -EEXIST : -ENOMEM;
@@ -941,6 +941,8 @@ struct inode *ovl_get_inode(struct super_block *sb,
err = -ENOMEM;
goto out_err;
}
+ ino = realinode->i_ino;
+ fsid = lowerpath->layer->fsid;
}
ovl_fill_inode(inode, realinode->i_mode, realinode->i_rdev, ino, fsid);
ovl_inode_init(inode, upperdentry, lowerdentry, oip->lowerdata);
--
2.20.1