[3.19.y-ckt stable] Patch "ovl: fix getcwd() failure after unsuccessful rmdir" has been added to the 3.19.y-ckt tree

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    ovl: fix getcwd() failure after unsuccessful rmdir

to the linux-3.19.y-queue branch of the 3.19.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.19.y-queue

This patch is scheduled to be released in version 3.19.8-ckt17.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.19.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

---8<------------------------------------------------------------

>From f9da9f69951d2dc7aeafdcc7ef736b1c465d8f3f Mon Sep 17 00:00:00 2001
From: Rui Wang <rui.y.wang at intel.com>
Date: Fri, 8 Jan 2016 23:09:59 +0800
Subject: ovl: fix getcwd() failure after unsuccessful rmdir

commit ce9113bbcbf45a57c082d6603b9a9f342be3ef74 upstream.

ovl_remove_upper() should do d_drop() only after it successfully
removes the dir, otherwise a subsequent getcwd() system call will
fail, breaking userspace programs.

This is to fix: https://bugzilla.kernel.org/show_bug.cgi?id=110491

Signed-off-by: Rui Wang <rui.y.wang at intel.com>
Reviewed-by: Konstantin Khlebnikov <koct9i at gmail.com>
Signed-off-by: Miklos Szeredi <miklos at szeredi.hu>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 fs/overlayfs/dir.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c
index 8ffc4b9..ddb1dc9 100644
--- a/fs/overlayfs/dir.c
+++ b/fs/overlayfs/dir.c
@@ -595,7 +595,8 @@ static int ovl_remove_upper(struct dentry *dentry, bool is_dir)
 	 * sole user of this dentry.  Too tricky...  Just unhash for
 	 * now.
 	 */
-	d_drop(dentry);
+	if (!err)
+		d_drop(dentry);
 	mutex_unlock(&dir->i_mutex);

 	return err;
--
2.7.0