kernel: add overlayfs stacking fix from upstream

Overlayfs stacking was broken in 4.1.12 but now fixed in upstream branch.
Stacking allows experimenting with configurations without the need to
reset a device to factory config.

Signed-off-by: Roman Yeryomin <roman@advem.lv>
Signed-off-by: Felix Fietkau <nbd@openwrt.org>

SVN-Revision: 47714
This commit is contained in:
Felix Fietkau 2015-12-03 13:54:33 +00:00
parent 2bcbe28580
commit b9849f286b

View file

@ -0,0 +1,33 @@
From 1c8a47df36d72ace8cf78eb6c228aa0f8027d3c2 Mon Sep 17 00:00:00 2001
From: Miklos Szeredi <miklos@szeredi.hu>
Date: Mon, 12 Oct 2015 15:56:20 +0200
Subject: ovl: fix open in stacked overlay
If two overlayfs filesystems are stacked on top of each other, then we need
recursion in ovl_d_select_inode().
I guess d_backing_inode() is supposed to do that. But currently it doesn't
and that functionality is open coded in vfs_open(). This is now copied
into ovl_d_select_inode() to fix this regression.
Reported-by: Alban Crequy <alban.crequy@gmail.com>
Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Fixes: 4bacc9c9234c ("overlayfs: Make f_path always point to the overlay...")
Cc: David Howells <dhowells@redhat.com>
Cc: <stable@vger.kernel.org> # v4.2+
---
fs/overlayfs/inode.c | 3 +++
1 file changed, 3 insertions(+)
--- a/fs/overlayfs/inode.c
+++ b/fs/overlayfs/inode.c
@@ -362,6 +362,9 @@ struct inode *ovl_d_select_inode(struct
ovl_path_upper(dentry, &realpath);
}
+ if (realpath.dentry->d_flags & DCACHE_OP_SELECT_INODE)
+ return realpath.dentry->d_op->d_select_inode(realpath.dentry, file_flags);
+
return d_backing_inode(realpath.dentry);
}