[4.2.y-ckt stable] Patch "jffs2: reduce the breakage on recovery from halfway failed rename()" has been added to the 4.2.y-ckt tree

[Kamal Mostafa]

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

    jffs2: reduce the breakage on recovery from halfway failed rename()

to the linux-4.2.y-queue branch of the 4.2.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-4.2.y-queue

This patch is scheduled to be released in version 4.2.8-ckt6.

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

For more information about the 4.2.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

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

>From f14a7aad67afe607410831471bfc1aa37b911d02 Mon Sep 17 00:00:00 2001
From: Al Viro <viro at zeniv.linux.org.uk>
Date: Mon, 7 Mar 2016 23:07:10 -0500
Subject: jffs2: reduce the breakage on recovery from halfway failed rename()

commit f93812846f31381d35c04c6c577d724254355e7f upstream.

d_instantiate(new_dentry, old_inode) is absolutely wrong thing to
do - it will oops if new_dentry used to be positive, for starters.
What we need is d_invalidate() the target and be done with that.

Signed-off-by: Al Viro <viro at zeniv.linux.org.uk>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 fs/jffs2/dir.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/fs/jffs2/dir.c b/fs/jffs2/dir.c
index 8118002..da37f2e 100644
--- a/fs/jffs2/dir.c
+++ b/fs/jffs2/dir.c
@@ -846,9 +846,14 @@ static int jffs2_rename (struct inode *old_dir_i, struct dentry *old_dentry,

 		pr_notice("%s(): Link succeeded, unlink failed (err %d). You now have a hard link\n",
 			  __func__, ret);
-		/* Might as well let the VFS know */
-		d_instantiate(new_dentry, d_inode(old_dentry));
-		ihold(d_inode(old_dentry));
+		/*
+		 * We can't keep the target in dcache after that.
+		 * For one thing, we can't afford dentry aliases for directories.
+		 * For another, if there was a victim, we _can't_ set new inode
+		 * for that sucker and we have to trigger mount eviction - the
+		 * caller won't do it on its own since we are returning an error.
+		 */
+		d_invalidate(new_dentry);
 		new_dir_i->i_mtime = new_dir_i->i_ctime = ITIME(now);
 		return ret;
 	}
--
2.7.0