kernel: backport upstream overlayfs fixes

First two patches weren't marked for stable but are dependencies for
laters ones. The rest of patches was marked for stable but most likely
will be backported to 4.5+ only so we need to get them on our own.

An important fix is eea2fb4851e9d ("ovl: proper cleanup of workdir") as
it allows mounting overlayfs with dirty workdir, e.g. after power cut.

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>

1 files changed, 73 insertions, 0 deletions

diff --git a/target/linux/generic/patches-4.4/051-0003-ovl-don-t-copy-up-opaqueness.patch b/target/linux/generic/patches-4.4/051-0003-ovl-don-t-copy-up-opaqueness.patch
new file mode 100644
index 0000000..da9e380
--- /dev/null
+++ b/target/linux/generic/patches-4.4/051-0003-ovl-don-t-copy-up-opaqueness.patch
@@ -0,0 +1,73 @@
+From 0956254a2d5b9e2141385514553aeef694dfe3b5 Mon Sep 17 00:00:00 2001
+From: Miklos Szeredi <mszeredi@redhat.com>
+Date: Mon, 8 Aug 2016 15:08:49 +0200
+Subject: [PATCH] ovl: don't copy up opaqueness
+
+When a copy up of a directory occurs which has the opaque xattr set, the
+xattr remains in the upper directory. The immediate behavior with overlayfs
+is that the upper directory is not treated as opaque, however after a
+remount the opaque flag is used and upper directory is treated as opaque.
+This causes files created in the lower layer to be hidden when using
+multiple lower directories.
+
+Fix by not copying up the opaque flag.
+
+To reproduce:
+
+ ----8<---------8<---------8<---------8<---------8<---------8<----
+mkdir -p l/d/s u v w mnt
+mount -t overlay overlay -olowerdir=l,upperdir=u,workdir=w mnt
+rm -rf mnt/d/
+mkdir -p mnt/d/n
+umount mnt
+mount -t overlay overlay -olowerdir=u:l,upperdir=v,workdir=w mnt
+touch mnt/d/foo
+umount mnt
+mount -t overlay overlay -olowerdir=u:l,upperdir=v,workdir=w mnt
+ls mnt/d
+ ----8<---------8<---------8<---------8<---------8<---------8<----
+
+output should be:  "foo  n"
+
+Reported-by: Derek McGowan <dmcg@drizz.net>
+Link: https://bugzilla.kernel.org/show_bug.cgi?id=151291
+Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
+Cc: <stable@vger.kernel.org>
+---
+ fs/overlayfs/copy_up.c   | 2 ++
+ fs/overlayfs/inode.c     | 2 +-
+ fs/overlayfs/overlayfs.h | 1 +
+ 3 files changed, 4 insertions(+), 1 deletion(-)
+
+--- a/fs/overlayfs/copy_up.c
++++ b/fs/overlayfs/copy_up.c
+@@ -48,6 +48,8 @@ int ovl_copy_xattr(struct dentry *old, s
+ 	}
+ 
+ 	for (name = buf; name < (buf + list_size); name += strlen(name) + 1) {
++		if (ovl_is_private_xattr(name))
++			continue;
+ retry:
+ 		size = vfs_getxattr(old, name, value, value_size);
+ 		if (size == -ERANGE)
+--- a/fs/overlayfs/inode.c
++++ b/fs/overlayfs/inode.c
+@@ -219,7 +219,7 @@ static int ovl_readlink(struct dentry *d
+ }
+ 
+ 
+-static bool ovl_is_private_xattr(const char *name)
++bool ovl_is_private_xattr(const char *name)
+ {
+ 	return strncmp(name, OVL_XATTR_PRE_NAME, OVL_XATTR_PRE_LEN) == 0;
+ }
+--- a/fs/overlayfs/overlayfs.h
++++ b/fs/overlayfs/overlayfs.h
+@@ -175,6 +175,7 @@ ssize_t ovl_getxattr(struct dentry *dent
+ ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size);
+ int ovl_removexattr(struct dentry *dentry, const char *name);
+ struct inode *ovl_d_select_inode(struct dentry *dentry, unsigned file_flags);
++bool ovl_is_private_xattr(const char *name);
+ 
+ struct inode *ovl_new_inode(struct super_block *sb, umode_t mode,
+ 			    struct ovl_entry *oe);